--- /dev/null
+/.idea/
+/target/
+/.classpath
+/.project
+/.settings/
+/Documentation/graphs/
+/Documentation/apidocs/
+/*.iml
+*.html
--- /dev/null
+:PROPERTIES:
+:ID: d69fec29-3842-4e10-aece-89829c522c79
+:END:
+#+TITLE: Aukio 3D Engine - Quick Reference
+#+LANGUAGE: en
+#+OPTIONS: H:20 num:20 author:nil
+
+Software-based 3D rendering engine (no OpenGL/DirectX). Pure Java
+rasterizer with texture support, lighting, CSG operations, and camera
+navigation.
+
+* Quick Lookup: "I Want To..."
+:PROPERTIES:
+:ID: 5136cb8e-4ade-4a28-91f7-3ec0ee98721c
+:END:
+
+| Task | Class (path) | Key Constructor/Method |
+|-------------------------------+-----------------------------------------------------+-----------------------------------------------------------|
+| *Create a window* | ~ViewFrame~ (~gui/ViewFrame.java~) | ~new ViewFrame()~ → ~.getViewPanel()~ |
+| *Add shapes to scene* | ~ShapeCollection~ (~raster/ShapeCollection.java~) | ~viewPanel.getRootShapeCollection().addShape(shape)~ |
+| *Position camera* | ~Camera~ (~geometry/Camera.java~) | ~camera.getTransform().setTranslation(Point3D)~ |
+| *Create a wireframe cube* | ~WireframeCube~ (~shapes/composite/wireframe/~) | ~new WireframeCube(center, halfSize, appearance)~ |
+| *Create a solid cube* | ~SolidPolygonCube~ (~shapes/composite/solid/~) | ~new SolidPolygonCube(center, halfSize, color)~ |
+| *Create a line* | ~Line~ (~shapes/basic/line/~) | ~new Line(p1, p2, color, width)~ |
+| *Create a polygon* | ~SolidPolygon~ (~shapes/basic/solidpolygon/~) | ~SolidPolygon.triangle(...)~ or ~.quad(...)~ |
+| *Create a sphere (wireframe)* | ~WireframeSphere~ (~shapes/composite/wireframe/~) | ~new WireframeSphere(center, radius, appearance)~ |
+| *Create a sphere (solid)* | ~SolidPolygonSphere~ (~shapes/composite/solid/~) | ~new SolidPolygonSphere(center, radius, segments, color)~ |
+| *Create text in 3D* | ~TextCanvas~ (~shapes/composite/textcanvas/~) | ~new TextCanvas(transform, text, fgColor, bgColor)~ |
+| *Add a light source* | ~LightSource~ (~raster/lighting/~) | ~lighting.addLight(new LightSource(pos, color))~ |
+| *Enable shading* | ~AbstractCompositeShape~ (~shapes/composite/base/~) | ~shape.setShadingEnabled(true)~ |
+| *CSG: subtract* | ~AbstractCompositeShape~ (~shapes/composite/base/~) | ~shape.subtract(otherShape)~ |
+| *CSG: union* | ~AbstractCompositeShape~ (~shapes/composite/base/~) | ~shape.union(otherShape)~ |
+| *CSG: intersect* | ~AbstractCompositeShape~ (~shapes/composite/base/~) | ~shape.intersect(otherShape)~ |
+| *Animate per-frame* | ~FrameListener~ (~gui/FrameListener.java~) | ~viewPanel.addFrameListener((panel, deltaMs) -> {...})~ |
+| *Handle mouse clicks* | ~MouseInteractionController~ (~gui/humaninput/~) | ~shape.setMouseInteractionController(controller)~ |
+| *Position/rotate shape* | ~AbstractCompositeShape~ (~shapes/composite/base/~) | ~new AbstractCompositeShape(location)~ |
+| *Hide/show shape groups* | ~ShapeCollection~ (~raster/ShapeCollection.java~) | ~.hideGroup("debug")~ / ~.showGroup("debug")~ |
+| *Create a billboard* | ~Billboard~ (~shapes/basic/~) | ~new Billboard(position, scale, texture)~ |
+| *Create a glowing point* | ~GlowingPoint~ (~shapes/basic/~) | ~new GlowingPoint(position, scale, color)~ |
+| *Render without a window* | ~Snapshot~ (~headless/Snapshot.java~) | ~Snapshot.render(scene, lighting, pose, w, h)~ |
+| *Assert pixels painted* | ~PixelAssertions~ (~headless/PixelAssertions.java~) | ~.unpaintedFraction(image, bg, x0, y0, x1, y1)~ |
+| *Compare against golden PNG* | ~GoldenImage~ (~headless/GoldenImage.java~) | ~.compare(actual, goldenFile, tolerance, maxFraction)~ |
+| *Dump scene state* | ~SceneDump~ (~headless/SceneDump.java~) | ~SceneDump.dump(scene, lighting, camera, gi)~ |
+
+* Code Examples
+:PROPERTIES:
+:ID: fdd7c315-c513-4925-8ca5-acb1f87a7380
+:END:
+
+** Basic Scene Setup
+
+#+begin_src java
+import eu.svjatoslav.aukio.e3d.gui.ViewFrame;
+import eu.svjatoslav.aukio.e3d.gui.ViewPanel;
+import eu.svjatoslav.aukio.e3d.renderer.raster.ShapeCollection;
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+
+// Create window with 3D view
+ViewFrame frame = new ViewFrame();
+ViewPanel viewPanel = frame.getViewPanel();
+ShapeCollection scene = viewPanel.getRootShapeCollection();
+
+// Position camera (behind origin, looking forward)
+viewPanel.getCamera().getTransform().setTranslation(new Point3D(0, 0, -200));
+
+// Add shapes here...
+// scene.addShape(...);
+#+end_src
+
+** Creating Shapes
+
+#+begin_src java
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.wireframe.*;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.solid.*;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.line.*;
+
+// Wireframe shapes (use LineAppearance for color/width)
+LineAppearance appearance = new LineAppearance(2.0, Color.CYAN);
+scene.addShape(new WireframeCube(new Point3D(0, 0, 200), 50, appearance));
+scene.addShape(new WireframeSphere(new Point3D(100, 0, 300), 40, appearance));
+scene.addShape(new WireframeBox(p1, p2, appearance));
+
+// Solid shapes (use Color directly)
+scene.addShape(new SolidPolygonCube(new Point3D(0, 0, 200), 50, Color.GREEN));
+scene.addShape(new SolidPolygonSphere(new Point3D(100, 0, 300), 40, 16, Color.RED));
+
+// Simple line
+scene.addShape(new Line(
+ new Point3D(-50, 0, 100),
+ new Point3D(50, 0, 100),
+ Color.YELLOW, 3.0
+));
+
+// Polygon (triangle or quad)
+scene.addShape(SolidPolygon.triangle(
+ new Point3D(0, 0, 0),
+ new Point3D(50, 0, 0),
+ new Point3D(25, 50, 0),
+ Color.BLUE
+));
+scene.addShape(SolidPolygon.quad(
+ new Point3D(-50, -50, 0),
+ new Point3D(50, -50, 0),
+ new Point3D(50, 50, 0),
+ new Point3D(-50, 50, 0),
+ Color.WHITE
+));
+#+end_src
+
+** Custom Composite Shape
+
+#+begin_src java
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape;
+
+AbstractCompositeShape myShape = new AbstractCompositeShape(new Point3D(0, 0, 200));
+myShape.addShape(new Line(p1, p2, Color.RED, 2.0));
+myShape.addShape(new SolidPolygonCube(Point3D.origin(), 10, Color.BLUE));
+scene.addShape(myShape);
+#+end_src
+
+** Lighting and Shading
+
+#+begin_src java
+import eu.svjatoslav.aukio.e3d.renderer.raster.lighting.*;
+
+LightingManager lighting = viewPanel.getLightingManager();
+lighting.addLight(new LightSource(new Point3D(100, -100, 200), Color.YELLOW));
+lighting.setAmbientLight(new Color(20, 20, 20));
+
+// Enable shading on solid shapes
+SolidPolygonSphere sphere = new SolidPolygonSphere(Point3D.origin(), 50, 16, Color.RED);
+sphere.setShadingEnabled(true);
+scene.addShape(sphere);
+#+end_src
+
+** CSG Operations (Boolean Operations)
+
+#+begin_src java
+// Create two shapes
+SolidPolygonCube box = new SolidPolygonCube(new Point3D(0, 0, 200), 50, Color.GREEN);
+SolidPolygonSphere sphere = new SolidPolygonSphere(new Point3D(0, 0, 200), 35, 16, Color.RED);
+
+// Subtract sphere from box (creates a box with spherical hole)
+box.subtract(sphere);
+scene.addShape(box);
+
+// Union: combine shapes
+// box.union(sphere);
+
+// Intersect: keep only overlapping parts
+// box.intersect(sphere);
+#+end_src
+
+** Text in 3D
+
+#+begin_src java
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.textcanvas.TextCanvas;
+import eu.svjatoslav.aukio.e3d.gui.TextPointer;
+import eu.svjatoslav.aukio.e3d.math.Transform;
+
+// Create text canvas
+Transform location = new Transform(new Point3D(0, 0, 500));
+TextCanvas canvas = new TextCanvas(location, "Hello World!", Color.WHITE, Color.BLACK);
+scene.addShape(canvas);
+
+// Or create blank canvas and write to it
+TextCanvas blank = new TextCanvas(location, new TextPointer(10, 40), Color.GREEN, Color.BLACK);
+blank.locate(0, 0); // row 0, column 0
+blank.print("Line 1");
+blank.locate(1, 0);
+blank.print("Line 2");
+blank.setForegroundColor(Color.YELLOW);
+blank.putChar('X');
+#+end_src
+
+** Animation with FrameListener
+
+#+begin_src java
+viewPanel.addFrameListener((panel, deltaMs) -> {
+ double rotationIncrement = deltaMs * 0.001; // radians per ms
+
+ // Update shape transform
+ currentAngle += rotationIncrement;
+ myShape.setTransform(new Transform(
+ myShape.getLocation(),
+ currentAngle, 0 // yaw, pitch
+ ));
+
+ return true; // return true to request repaint
+});
+#+end_src
+
+** Camera Control
+
+#+begin_src java
+import eu.svjatoslav.aukio.e3d.math.Quaternion;
+
+Camera camera = viewPanel.getCamera();
+
+// Set position
+camera.getTransform().setTranslation(new Point3D(100, -50, -300));
+
+// Set orientation (quaternion from yaw/pitch angles)
+camera.getTransform().getRotation().set(Quaternion.fromAngles(0.5, -0.3));
+
+// Look at a specific point (convenience method)
+// camera.lookAt(new Point3D(0, 0, 200));
+#+end_src
+
+** Mouse Interaction on Shapes
+
+#+begin_src java
+import eu.svjatoslav.aukio.e3d.gui.humaninput.MouseInteractionController;
+import eu.svjatoslav.aukio.e3d.gui.humaninput.MouseEvent;
+
+SolidPolygonCube clickableCube = new SolidPolygonCube(Point3D.origin(), 50, Color.BLUE);
+clickableCube.setMouseInteractionController(new MouseInteractionController() {
+ @Override
+ public void mouseClicked(final MouseEvent event) {
+ System.out.println("Cube clicked at: " + event.coordinate);
+ }
+
+ @Override
+ public void mouseEntered(final MouseEvent event) {
+ clickableCube.setColor(Color.RED);
+ }
+
+ @Override
+ public void mouseExited(final MouseEvent event) {
+ clickableCube.setColor(Color.BLUE);
+ }
+});
+scene.addShape(clickableCube);
+#+end_src
+
+* Class Catalog
+:PROPERTIES:
+:ID: 5522594a-969f-4cdb-b80e-d3d6bc732647
+:END:
+
+** Geometry (~geometry/~)
+
+| Class | File | Purpose | Key Methods |
+|-----------+----------------+---------------------------------------------------------+-------------------------------------------------------------------------------------------------------------------|
+| ~Point3D~ | ~Point3D.java~ | Mutable 3D point/vector. *Public fields:* ~x~, ~y~, ~z~ | ~.add()~, ~.subtract()~, ~.multiply()~, ~.rotate()~, ~.getDistanceTo()~, ~.clone()~, ~.withAdded()~ (returns new) |
+| ~Point2D~ | ~Point2D.java~ | 2D screen coordinate | ~.add()~, ~.subtract()~, ~.to3D()~ |
+| ~Box~ | ~Box.java~ | Axis-aligned bounding box | ~.getCenter()~, ~.enlarge()~, ~.intersectsAABB()~ |
+| ~Frustum~ | ~Frustum.java~ | View frustum (6 planes) | ~.update()~, ~.intersectsAABB()~ |
+| ~BspTree~ | ~BspTree.java~ | BSP tree for CSG | ~.addPolygons()~, ~.clipPolygons()~, ~.invert()~, ~.allPolygons()~ |
+| ~Plane~ | ~Plane.java~ | Infinite plane (Hesse normal) | ~.fromPoints()~, ~.splitPolygon()~ |
+
+** Math (~math/~)
+
+| Class | File | Purpose | Key Methods |
+|------------------+-----------------------+-------------------------------+---------------------------------------------------------------------------------|
+| ~Transform~ | ~Transform.java~ | Translation + rotation | ~.setTranslation()~, ~.transform(point)~, ~.withTransformed()~ |
+| ~TransformStack~ | ~TransformStack.java~ | Stack of transforms | ~.addTransform()~, ~.transform()~, ~.dropTransform()~ |
+| ~Quaternion~ | ~Quaternion.java~ | 3D rotation (unit quaternion) | ~.fromAngles(yaw, pitch)~, ~.multiply()~, ~.invert()~, ~.toMatrix3x3()~ |
+| ~Vertex~ | ~Vertex.java~ | Wraps Point3D + transform | ~.coordinate~, ~.transformedCoordinate~, ~.calculateLocationRelativeToViewer()~ |
+
+** Renderer Core (~renderer/raster/~)
+
+| Class | File | Purpose | Key Methods |
+|--------------------+-------------------------+----------------------------------+-----------------------------------------------------------------------------------------------------|
+| ~Color~ | ~Color.java~ | RGBA color (NOT java.awt.Color!) | ~.set(r,g,b,a)~, ~.toAwtColor()~. Constants: ~RED~, ~GREEN~, ~BLUE~, ~BLACK~, ~WHITE~, ~CYAN~, etc. |
+| ~ShapeCollection~ | ~ShapeCollection.java~ | Root scene container | ~.addShape()~, ~.hideGroup()~, ~.showGroup()~, ~.removeGroup()~ |
+| ~RenderAggregator~ | ~RenderAggregator.java~ | Collects, sorts, paints shapes | ~.queueShapeForRendering()~, ~.sort()~, ~.paint()~ |
+
+** Shapes - Base (~renderer/raster/shapes/~)
+
+| Class | File | Purpose |
+|---------------------------+---------------------------------------+-----------------------------------------------------------------|
+| ~AbstractShape~ | ~shapes/AbstractShape.java~ | Base class for all shapes. Bounding box caching. |
+| ~AbstractCoordinateShape~ | ~shapes/AbstractCoordinateShape.java~ | Base for shapes with vertices. Has ~List<Vertex>~, ~onScreenZ~. |
+
+** Shapes - Basic (~shapes/basic/~)
+
+| Class | File | Purpose | Constructor |
+|--------------------+-----------------------------------------------+------------------------------+---------------------------------------------------------|
+| ~Line~ | ~basic/line/Line.java~ | 3D line segment | ~new Line(p1, p2, color, width)~ |
+| ~LineAppearance~ | ~basic/line/LineAppearance.java~ | Factory for consistent lines | ~new LineAppearance(width, color)~ → ~.getLine(p1, p2)~ |
+| ~SolidPolygon~ | ~basic/solidpolygon/SolidPolygon.java~ | Solid convex N-gon | ~SolidPolygon.triangle(...)~ or ~.quad(...)~ |
+| ~TexturedTriangle~ | ~basic/texturedpolygon/TexturedTriangle.java~ | Textured triangle with UV | ~new TexturedTriangle(v1,v2,v3,texture)~ |
+| ~Billboard~ | ~basic/Billboard.java~ | Texture facing camera | ~new Billboard(position, scale, texture)~ |
+| ~GlowingPoint~ | ~basic/GlowingPoint.java~ | Glowing circular point | ~new GlowingPoint(position, scale, color)~ |
+
+** Shapes - Composite Wireframe (~shapes/composite/wireframe/~)
+
+| Class | Constructor |
+|---------------------+-------------------------------------------------------------|
+| ~WireframeCube~ | ~new WireframeCube(center, halfSize, appearance)~ |
+| ~WireframeBox~ | ~new WireframeBox(corner1, corner2, appearance)~ |
+| ~WireframeSphere~ | ~new WireframeSphere(center, radius, appearance)~ |
+| ~WireframeCylinder~ | ~new WireframeCylinder(center, radius, height, appearance)~ |
+| ~WireframeCone~ | ~new WireframeCone(center, radius, height, appearance)~ |
+| ~WireframeArrow~ | ~new WireframeArrow(start, end, appearance)~ |
+| ~Grid2D~ | 2D grid plane |
+| ~Grid3D~ | 3D grid in space |
+
+** Shapes - Composite Solid (~shapes/composite/solid/~)
+
+| Class | Constructor |
+|------------------------------+-----------------------------------------------------------|
+| ~SolidPolygonCube~ | ~new SolidPolygonCube(center, halfSize, color)~ |
+| ~SolidPolygonRectangularBox~ | ~new SolidPolygonRectangularBox(corner1, corner2, color)~ |
+| ~SolidPolygonSphere~ | ~new SolidPolygonSphere(center, radius, segments, color)~ |
+| ~SolidPolygonCylinder~ | Solid cylinder |
+| ~SolidPolygonCone~ | Solid cone |
+| ~SolidPolygonArrow~ | Solid arrow |
+
+** Shapes - Composite Base (~shapes/composite/base/~)
+
+| Class | File | Purpose | Key Methods |
+|--------------------------+------------------------------------+-----------------------+-------------------------------------------------------------------------------------------------|
+| ~AbstractCompositeShape~ | ~base/AbstractCompositeShape.java~ | Group shapes, CSG ops | ~.addShape()~, ~.subtract()~, ~.union()~, ~.intersect()~, ~.setShadingEnabled()~, ~.setColor()~ |
+| ~LightmappedCompositeShape~ | ~composite/LightmappedCompositeShape.java~ | Composite that fan-triangulates and optionally carries GI lightmaps | ~.setLightmappingEnabled(true)~ |
+| ~TriangleMeshBlock~ | ~basic/texturedpolygon/TriangleMeshBlock.java~ | SoA fast path for large textured triangle meshes (flat double[] arrays, one tight transform loop) | build from mesh data |
+
+** Text (~shapes/composite/textcanvas/~)
+
+| Class | File | Purpose | Key Methods |
+|--------------+------------------------------+-----------------+-----------------------------------------------------------------------------------|
+| ~TextCanvas~ | ~textcanvas/TextCanvas.java~ | Text grid in 3D | ~.print()~, ~.locate(row,col)~, ~.clear()~, ~.setForegroundColor()~, ~.putChar()~ |
+
+** Texture (~renderer/raster/texture/~)
+
+| Class | File | Purpose |
+|--------------------+---------------------------------+----------------------------------------------|
+| ~Texture~ | ~texture/Texture.java~ | 2D texture with mipmaps |
+| ~TextureBitmap~ | ~texture/TextureBitmap.java~ | Raw pixel array for one mipmap level |
+| ~TextureGenerator~ | ~texture/TextureGenerator.java~ | Factory for common textures (glows, borders) |
+
+** Lighting (~renderer/raster/lighting/~)
+
+| Class | File | Purpose | Key Methods |
+|-------------------+---------------------------------+----------------+-----------------------------------------------------------|
+| ~LightingManager~ | ~lighting/LightingManager.java~ | Manages lights | ~.addLight()~, ~.setAmbientLight()~, ~.computeLighting()~ |
+| ~LightSource~ | ~lighting/LightSource.java~ | Point light | ~new LightSource(position, color)~ → ~.setIntensity()~ |
+
+** GUI (~gui/~)
+
+| Class | File | Purpose | Key Methods |
+|-----------------+--------------------------+------------------------------+--------------------------------------------------------------------------------------------------------|
+| ~ViewPanel~ | ~gui/ViewPanel.java~ | AWT Canvas, render loop | ~.getRootShapeCollection()~, ~.getCamera()~, ~.getLightingManager()~, ~.addFrameListener()~, ~.stop()~ |
+| ~ViewFrame~ | ~gui/ViewFrame.java~ | JFrame wrapper | ~new ViewFrame()~ → ~.getViewPanel()~ |
+| ~Camera~ | ~geometry/Camera.java~ | Viewer position/orientation | ~.getTransform()~, ~.setTransform()~ |
+| ~FrameListener~ | ~gui/FrameListener.java~ | Per-frame callback interface | ~.onFrame(panel, deltaMs)~ → return true to repaint |
+
+** Input (~gui/humaninput/~)
+
+| Class | File | Purpose |
+|------------------------------+----------------------------------------------+--------------------------------|
+| ~InputManager~ | ~humaninput/InputManager.java~ | Mouse/keyboard tracking |
+| ~MouseInteractionController~ | ~humaninput/MouseInteractionController.java~ | Interface for clickable shapes |
+| ~KeyboardFocusStack~ | ~humaninput/KeyboardFocusStack.java~ | Focus management for widgets |
+
+** Octree Renderer (~renderer/octree/~)
+
+Alternative rendering path for voxel volumes with ray tracing.
+
+| Class | File | Purpose |
+|----------------+-----------------------------------+-----------------------------|
+| ~OctreeVolume~ | ~octree/OctreeVolume.java~ | Sparse voxel octree storage |
+| ~RayTracer~ | ~octree/raytracer/RayTracer.java~ | Ray tracing renderer |
+
+* Architecture & Key Concepts
+:PROPERTIES:
+:ID: 4be2246b-fcb6-4a1f-bcf8-7d657a67d957
+:END:
+
+** Coordinate System (CRITICAL)
+
+Aukio 3D uses *left-handed coordinates* matching 2D screen space:
+
+| Axis | Positive = | Example |
+|------+-------------+----------------------------------|
+| X | RIGHT | Larger X = further right |
+| Y | DOWN | Smaller Y = higher (up visually) |
+| Z | INTO screen | Negative Z = closer to camera |
+
+*To place A ABOVE B:* give A a *smaller Y* (~y - offset~)
+*To place A BELOW B:* give A a *larger Y* (~y + offset~)
+
+This is opposite to Y-up engines (OpenGL, Unity, Blender).
+
+** Shape Hierarchy
+
+#+begin_example
+AbstractShape (base)
+ ├── AbstractCoordinateShape (has vertices)
+ │ ├── Line
+ │ ├── SolidPolygon
+ │ ├── TexturedTriangle
+ │ ├── Billboard
+ │ └── GlowingPoint
+ └── AbstractCompositeShape (groups shapes)
+ ├── Wireframe shapes (WireframeCube, WireframeSphere, ...)
+ ├── Solid shapes (SolidPolygonCube, SolidPolygonSphere, ...)
+ └── TextCanvas
+#+end_example
+
+** Render Pipeline
+
+#+begin_example
+ViewPanel.renderFrame()
+ 1. ShapeCollection.transformShapes() — apply camera transform, cull, queue
+ 2. ShapeCollection.sortShapes() — radix sort by Z (back-to-front)
+ 3. ShapeCollection.paintShapes() — tiled parallel paint, two-pass z-buffer
+ (opaque front-to-back with depth writes, then alpha back-to-front)
+ 4. BufferStrategy.show() — page flip to display
+#+end_example
+
+- Shapes implement ~transform()~ to project from world to screen space
+- Shapes implement ~paint()~ to rasterize to pixel buffer
+- ~onScreenZ~ determines render order (set during transform phase)
+
+** Backface Culling
+
+Uses signed area in screen space:
+- ~signedArea < 0~ → front-facing (CCW winding)
+- ~signedArea > 0~ → back-facing (CW winding)
+
+Vertex order for front face: *top → lower-left → lower-right* (as seen from camera)
+
+* Build & Test
+:PROPERTIES:
+:ID: 7909eb6a-c9a0-45f6-b1a5-a347e469c6cf
+:END:
+
+#+begin_src bash
+# Build
+mvn clean install
+
+# Run all tests
+mvn test
+
+# Run single test class
+mvn test -Dtest=TextLineTest
+
+# Run specific test method
+mvn test -Dtest=TextLineTest#testAddIdent
+
+# Golden-image regression tests (aukio-3d-demos repo)
+cd ../aukio-3d-demos && mvn clean package
+mvn -q dependency:build-classpath -Dmdep.outputFile=cp.txt
+java -cp "target/classes:$(cat cp.txt)" \
+ eu.svjatoslav.aukio.e3d.examples.goldens.HouseGoldens # verify
+java -cp "target/classes:$(cat cp.txt)" \
+ eu.svjatoslav.aukio.e3d.examples.goldens.HouseGoldens --update # regenerate goldens
+
+# Regenerate all HTML documentation (org -> HTML, darksun theme)
+Documentation/export-docs.sh # export
+Documentation/export-docs.sh --check # export + headless-Chrome screenshots to /tmp
+#+end_src
+
+Test files: ~src/test/java/~ (JUnit 4)
+
+* Headless Testing Toolkit (~headless/~)
+:PROPERTIES:
+:ID: b1f4a2c8-headless-toolkit
+:END:
+
+Windowless rendering and verification — no Swing frame, no X display,
+no render thread. Drives the same transform/sort/paint pipeline the
+on-screen path uses. Built for tests, doc tooling and AI agents.
+
+** Rendering a snapshot
+
+#+begin_src java
+import eu.svjatoslav.aukio.e3d.headless.Snapshot;
+
+// Pose string = "x, y, z, yaw, pitch, roll" — the exact format demos
+// print and bug reports quote. Snapshot.cameraFromPose / poseString
+// convert both ways.
+BufferedImage image = Snapshot.render(scene, lighting,
+ "290.31, -35.59, -2.10, -0.58, -0.15, 0.0", 640, 480);
+Snapshot.save(image, "/tmp/snap.png");
+#+end_src
+
+~Snapshot.render(scene, lighting, camera, w, h)~ is the Camera-based
+overload; ~Snapshot.renderInto(scene, camera, ctx, backgroundArgb)~
+paints into an existing ~RenderingContext~ with a chosen background
+(sentinel color = "unpainted" for hole detection).
+
+** Pixel assertions
+
+#+begin_src java
+import eu.svjatoslav.aukio.e3d.headless.PixelAssertions;
+
+double holes = PixelAssertions.unpaintedFraction(image, 0,
+ 0.15, 0.45, 0.85, 1.0); // lower-center band, relative coords
+long red = PixelAssertions.countColor(image, 0xFF0000);
+String grid = PixelAssertions.dumpPixelGrid(image, 320, 240, 3, 8);
+#+end_src
+
+** Golden-image comparison
+
+#+begin_src java
+import eu.svjatoslav.aukio.e3d.headless.GoldenImage;
+
+GoldenImage.Result r = GoldenImage.compare(actual,
+ new File("goldens/house.png"), 4, 0.005); // channel tol, max diff fraction
+GoldenImage.saveDiff(actual, goldenFile, "/tmp/diff.png"); // red = differs
+#+end_src
+
+CLI: ~java eu.svjatoslav.aukio.e3d.headless.GoldenImage a.png b.png [tol] [maxFrac]~
+(exit 0 = match, 1 = differ).
+
+The House demo has ready-made goldens in the aukio-3d-demos repo:
+~eu.svjatoslav.aukio.e3d.examples.goldens.HouseGoldens~ checks two poses
+(default view + the near-plane straddle bug pose) against
+~aukio-3d-demos/goldens/*.png~ and asserts the floor has no holes.
+Run ~--update~ to regenerate after an intentional visual change.
+
+** Scene dump
+
+#+begin_src java
+import eu.svjatoslav.aukio.e3d.headless.SceneDump;
+
+System.out.println(SceneDump.dump(scene, lighting, camera, gi));
+// shapes: 5 top-level, 546 queued for rendering
+// lights: 4 (ambient #181818) + per-light pos/color/intensity
+// camera: 290.31, -35.59, -2.10, -0.58, -0.15, -0.00
+// GI: running, 152034 work items, converged
+#+end_src
+
+** Engine API added for headless use
+
+- ~ShapeCollection.transformShapes(Camera, RenderingContext)~ — camera-based
+ overload; the ~ViewPanel~ variant delegates to it
+- ~ShapeCollection.getRootComposite()~ — direct root access (GI snapshots)
+- ~RenderingContext.getImage()~ — the backing BufferedImage
+- ~GlobalIllumination.isRunning() / isConverged() / getWorkItemCount()~
+
+** House demo scene without a window (aukio-3d-demos)
+
+~HouseDemo.buildHouse(house)~, ~HouseDemo.addFurniture(house)~ and
+~HouseDemo.addLights(lighting, scene)~ are public: tests and tools can
+rebuild the exact demo scene headlessly.
+
+* Tips for AI Agents
+:PROPERTIES:
+:ID: 597b2b14-1ee1-440b-bd40-ab7f3ed405de
+:END:
+
+1. *Always use project Color:* ~eu.svjatoslav.aukio.e3d.renderer.raster.Color~ (NOT ~java.awt.Color~)
+2. *Point3D is mutable:* Clone before storing references: ~point.clone()~
+3. *Y is down:* Remember coordinate system when positioning elements
+4. *SolidPolygon works for quads:* Use ~SolidPolygon.quad(p1,p2,p3,p4,color)~ - automatically triangulated
+5. *CSG on AbstractCompositeShape:* Only composite shapes support ~subtract()~, ~union()~, ~intersect()~
+6. *Animations via FrameListener:* Return ~true~ from ~onFrame()~ to trigger repaint
+7. *Shading needs lighting:* ~setShadingEnabled(true)~ + add ~LightSource~ to ~LightingManager~
+8. *Wireframe shapes need LineAppearance:* ~new LineAppearance(width, Color)~ for consistent line styling
+9. *Group visibility:* Use ~.addShape(shape, "groupName")~ then ~.hideGroup()~ / ~.showGroup()~
+
+* Documentation (Org Mode)
+:PROPERTIES:
+:ID: 1d942e3b-6071-440f-bd9b-876c8f7c53de
+:END:
+
+| Path | Topic |
+|----------------------------------------------+---------------------------------------------------------------------|
+| ~Documentation/index.org~ | Main: coordinate system, shapes, CSG, developer tools |
+| ~Documentation/Rendering loop/index.org~ | 5-phase pipeline, multi-threaded paint |
+| ~Documentation/Shading/index.org~ | Lambert shading, lights, distance attenuation |
+| ~Documentation/CSG/index.org~ | Boolean ops via BSP trees |
+| ~Documentation/Frustum culling/index.org~ | View frustum culling |
+| ~Documentation/Near plane clip/index.org~ | Near-plane polygon clipping (straddling geometry) |
+| ~Documentation/Global illumination/index.org~ | Progressive GI: lightmaps, bounces, convergence |
+| ~Documentation/Perspective correct textures/index.org~ | Texture mapping math |
+| ~Documentation/Stereoscopic rendering/index.org~ | Side-by-side stereo: two passes, per-eye viewports, IPD |
+| ~Documentation/Depth buffer/index.org~ | Two-pass z-buffer, zw, depth margin, Hi-Z pyramid, determinism |
+| ~Documentation/SDF textures/index.org~ | SDF text: glyph fields, coverage window, TextCanvas |
+
+Regenerate all HTML: ~Documentation/export-docs.sh~ (add ~--check~ for rendered
+screenshots of every page).
+
+Every heading in a doc page needs a ~:CUSTOM_ID:~ property (kebab-case slug)
+right below the heading line. Without it org-html export generates
+~org<hex>~ anchors and TOC links come out as
+~#outline-container-org5fddfe7~ instead of human-readable
+~#outline-container-engine-internals~.
--- /dev/null
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+3. Public License Fallback. Should any part of the Waiver for any reason
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+partial invalidity or ineffectiveness shall not invalidate the remainder
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+will not (i) exercise any of his or her remaining Copyright and Related
+Rights in the Work or (ii) assert any associated claims and causes of
+action with respect to the Work, in either case contrary to Affirmer's
+express Statement of Purpose.
+
+4. Limitations and Disclaimers.
+
+ a. No trademark or patent rights held by Affirmer are waived, abandoned,
+ surrendered, licensed or otherwise affected by this document.
+ b. Affirmer offers the Work as-is and makes no representations or
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+ c. Affirmer disclaims responsibility for clearing rights of other persons
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+ Further, Affirmer disclaims responsibility for obtaining any necessary
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+ d. Affirmer understands and acknowledges that Creative Commons is not a
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+ this CC0 or use of the Work.
--- /dev/null
+<svg viewBox="0 0 620 190" width="620" height="190" xmlns="http://www.w3.org/2000/svg">
+ <defs>
+ <filter id="glow">
+ <feGaussianBlur stdDeviation="1.5" result="blur"/>
+ <feMerge>
+ <feMergeNode in="blur"/>
+ <feMergeNode in="SourceGraphic"/>
+ </feMerge>
+ </filter>
+ <marker id="arr" viewBox="0 0 8 8" refX="7" refY="4" markerWidth="7" markerHeight="7" orient="auto">
+ <path d="M0 0 L8 4 L0 8 Z" fill="#40b0d0"/>
+ </marker>
+ <marker id="arrRed" viewBox="0 0 8 8" refX="7" refY="4" markerWidth="7" markerHeight="7" orient="auto">
+ <path d="M0 0 L8 4 L0 8 Z" fill="#FF4444"/>
+ </marker>
+ </defs>
+
+ <rect width="620" height="190" fill="#061018"/>
+ <g stroke="#1a3a4a" stroke-width="0.5">
+ <line x1="0" y1="40" x2="620" y2="40"/><line x1="0" y1="80" x2="620" y2="80"/>
+ <line x1="0" y1="120" x2="620" y2="120"/><line x1="0" y1="160" x2="620" y2="160"/>
+ <line x1="40" y1="0" x2="40" y2="190"/><line x1="80" y1="0" x2="80" y2="190"/>
+ <line x1="120" y1="0" x2="120" y2="190"/><line x1="160" y1="0" x2="160" y2="190"/>
+ <line x1="200" y1="0" x2="200" y2="190"/><line x1="240" y1="0" x2="240" y2="190"/>
+ <line x1="280" y1="0" x2="280" y2="190"/><line x1="320" y1="0" x2="320" y2="190"/>
+ <line x1="360" y1="0" x2="360" y2="190"/><line x1="400" y1="0" x2="400" y2="190"/>
+ <line x1="440" y1="0" x2="440" y2="190"/><line x1="480" y1="0" x2="480" y2="190"/>
+ <line x1="520" y1="0" x2="520" y2="190"/><line x1="560" y1="0" x2="560" y2="190"/>
+ <line x1="600" y1="0" x2="600" y2="190"/>
+ </g>
+
+ <!-- step 1: render -->
+ <rect x="20" y="55" width="110" height="60" rx="8" fill="rgba(32,112,192,0.12)" stroke="#2070c0" stroke-width="2"/>
+ <text x="75" y="80" fill="#2070c0" font-size="10" font-family="monospace" text-anchor="middle">Snapshot.render</text>
+ <text x="75" y="97" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">scene + pose</text>
+
+ <line x1="130" y1="85" x2="158" y2="85" stroke="#40b0d0" stroke-width="2" marker-end="url(#arr)"/>
+
+ <!-- step 2: golden file -->
+ <rect x="160" y="20" width="110" height="40" rx="8" fill="rgba(192,80,136,0.12)" stroke="#c05088" stroke-width="2"/>
+ <text x="215" y="38" fill="#c05088" font-size="10" font-family="monospace" text-anchor="middle">goldens/*.png</text>
+ <text x="215" y="52" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">committed reference</text>
+ <line x1="215" y1="60" x2="215" y2="80" stroke="#c05088" stroke-width="1.5" stroke-dasharray="3 2" marker-end="url(#arr)"/>
+
+ <!-- step 3: compare decision -->
+ <polygon points="215,85 265,55 315,85 265,115" fill="rgba(64,176,208,0.12)" stroke="#40b0d0" stroke-width="2"/>
+ <text x="265" y="82" fill="#40b0d0" font-size="10" font-family="monospace" text-anchor="middle">GoldenImage</text>
+ <text x="265" y="95" fill="#40b0d0" font-size="10" font-family="monospace" text-anchor="middle">.compare</text>
+
+ <!-- PASS branch -->
+ <line x1="315" y1="85" x2="348" y2="85" stroke="#39FF14" stroke-width="2" marker-end="url(#arr)"/>
+ <rect x="350" y="60" width="90" height="50" rx="8" fill="rgba(57,255,20,0.12)" stroke="#39FF14" stroke-width="2"/>
+ <text x="395" y="82" fill="#39FF14" font-size="11" font-family="monospace" text-anchor="middle" filter="url(#glow)">PASS</text>
+ <text x="395" y="98" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">exit 0</text>
+
+ <!-- FAIL branch -->
+ <path d="M265 115 L265 140 L 348 140" stroke="#FF4444" stroke-width="2" fill="none" marker-end="url(#arrRed)"/>
+ <rect x="350" y="115" width="120" height="50" rx="8" fill="rgba(255,68,68,0.1)" stroke="#FF4444" stroke-width="2"/>
+ <text x="410" y="136" fill="#FF4444" font-size="11" font-family="monospace" text-anchor="middle" filter="url(#glow)">FAIL, exit 1</text>
+ <text x="410" y="152" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">+ diff PNG to /tmp</text>
+
+ <!-- human decision -->
+ <line x1="470" y1="140" x2="498" y2="140" stroke="#FF4444" stroke-width="2" marker-end="url(#arrRed)"/>
+ <rect x="500" y="115" width="100" height="50" rx="8" fill="rgba(255,136,51,0.1)" stroke="#FF8833" stroke-width="2"/>
+ <text x="550" y="133" fill="#FF8833" font-size="9" font-family="monospace" text-anchor="middle">bug? fix code</text>
+ <text x="550" y="146" fill="#FF8833" font-size="9" font-family="monospace" text-anchor="middle">intended? run</text>
+ <text x="550" y="158" fill="#FF8833" font-size="9" font-family="monospace" text-anchor="middle">--update</text>
+
+ <!-- update loop back to golden -->
+ <path d="M550 115 L 550 30 L 272 30" stroke="#FF8833" stroke-width="1.5" fill="none" stroke-dasharray="4 3" marker-end="url(#arr)"/>
+ <text x="420" y="22" fill="#FF8833" font-size="9" font-family="monospace" text-anchor="middle">regenerates reference</text>
+
+ <text x="310" y="182" fill="#aaa" font-size="9" font-family="monospace" text-anchor="middle">tolerance: per-channel delta + max differing-pixel fraction — shading is deterministic, keep both tight</text>
+</svg>
--- /dev/null
+<svg viewBox="0 0 640 480" width="640" height="480" xmlns="http://www.w3.org/2000/svg">
+ <defs>
+ <filter id="glow">
+ <feGaussianBlur stdDeviation="2" result="blur"/>
+ <feMerge>
+ <feMergeNode in="blur"/>
+ <feMergeNode in="SourceGraphic"/>
+ </feMerge>
+ </filter>
+ <marker id="arr" viewBox="0 0 8 8" refX="7" refY="4" markerWidth="7" markerHeight="7" orient="auto">
+ <path d="M0 0 L8 4 L0 8 Z" fill="#40b0d0"/>
+ </marker>
+ </defs>
+
+ <rect width="640" height="480" fill="#061018"/>
+ <g stroke="#1a3a4a" stroke-width="0.5">
+ <line x1="0" y1="40" x2="640" y2="40"/><line x1="0" y1="80" x2="640" y2="80"/>
+ <line x1="0" y1="120" x2="640" y2="120"/><line x1="0" y1="160" x2="640" y2="160"/>
+ <line x1="0" y1="200" x2="640" y2="200"/><line x1="0" y1="240" x2="640" y2="240"/>
+ <line x1="0" y1="280" x2="640" y2="280"/><line x1="0" y1="320" x2="640" y2="320"/>
+ <line x1="0" y1="360" x2="640" y2="360"/><line x1="0" y1="400" x2="640" y2="400"/>
+ <line x1="0" y1="440" x2="640" y2="440"/>
+ <line x1="40" y1="0" x2="40" y2="480"/><line x1="80" y1="0" x2="80" y2="480"/>
+ <line x1="120" y1="0" x2="120" y2="480"/><line x1="160" y1="0" x2="160" y2="480"/>
+ <line x1="200" y1="0" x2="200" y2="480"/><line x1="240" y1="0" x2="240" y2="480"/>
+ <line x1="280" y1="0" x2="280" y2="480"/><line x1="320" y1="0" x2="320" y2="480"/>
+ <line x1="360" y1="0" x2="360" y2="480"/><line x1="400" y1="0" x2="400" y2="480"/>
+ <line x1="440" y1="0" x2="440" y2="480"/><line x1="480" y1="0" x2="480" y2="480"/>
+ <line x1="520" y1="0" x2="520" y2="480"/><line x1="560" y1="0" x2="560" y2="480"/>
+ <line x1="600" y1="0" x2="600" y2="480"/>
+ </g>
+
+ <!-- ============ two entry lanes feeding ONE shared pipeline ============ -->
+
+ <!-- lane 1: on-screen app -->
+ <rect x="40" y="60" width="200" height="66" rx="8" fill="rgba(255,136,51,0.12)" stroke="#FF8833" stroke-width="2"/>
+ <text x="140" y="86" fill="#FF8833" font-size="12" font-family="monospace" text-anchor="middle" filter="url(#glow)">ViewPanel</text>
+ <text x="140" y="103" fill="#ccc" font-size="9" font-family="monospace" text-anchor="middle">window + render thread</text>
+ <text x="140" y="116" fill="#ccc" font-size="9" font-family="monospace" text-anchor="middle">camera from user input</text>
+
+ <!-- lane 2: headless -->
+ <rect x="40" y="354" width="200" height="66" rx="8" fill="rgba(57,255,20,0.1)" stroke="#39FF14" stroke-width="2"/>
+ <text x="140" y="380" fill="#39FF14" font-size="12" font-family="monospace" text-anchor="middle" filter="url(#glow)">Snapshot.render()</text>
+ <text x="140" y="397" fill="#ccc" font-size="9" font-family="monospace" text-anchor="middle">no window, no display</text>
+ <text x="140" y="410" fill="#ccc" font-size="9" font-family="monospace" text-anchor="middle">camera from pose string</text>
+
+ <!-- shared pipeline core -->
+ <rect x="300" y="170" width="140" height="140" rx="10" fill="rgba(32,112,192,0.12)" stroke="#2070c0" stroke-width="2.5"/>
+ <text x="370" y="196" fill="#2070c0" font-size="13" font-family="monospace" text-anchor="middle" filter="url(#glow)">SAME pipeline</text>
+ <text x="370" y="228" fill="#ccc" font-size="10" font-family="monospace" text-anchor="middle">transform</text>
+ <text x="370" y="248" fill="#ccc" font-size="10" font-family="monospace" text-anchor="middle">↓</text>
+ <text x="370" y="266" fill="#ccc" font-size="10" font-family="monospace" text-anchor="middle">sort by Z</text>
+ <text x="370" y="284" fill="#ccc" font-size="10" font-family="monospace" text-anchor="middle">↓</text>
+ <text x="370" y="302" fill="#ccc" font-size="10" font-family="monospace" text-anchor="middle">paint</text>
+
+ <!-- outputs -->
+ <rect x="500" y="60" width="110" height="50" rx="8" fill="rgba(255,136,51,0.08)" stroke="#FF8833" stroke-width="1.5"/>
+ <text x="555" y="81" fill="#FF8833" font-size="11" font-family="monospace" text-anchor="middle">screen</text>
+ <text x="555" y="97" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">BufferStrategy</text>
+
+ <rect x="490" y="330" width="130" height="90" rx="8" fill="rgba(57,255,20,0.07)" stroke="#39FF14" stroke-width="1.5"/>
+ <text x="555" y="352" fill="#39FF14" font-size="11" font-family="monospace" text-anchor="middle">BufferedImage</text>
+ <text x="555" y="370" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">→ PNG (Snapshot.save)</text>
+ <text x="555" y="385" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">→ PixelAssertions</text>
+ <text x="555" y="400" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">→ GoldenImage</text>
+
+ <!-- lane arrows converging into the core -->
+ <path d="M240 93 C 290 93, 270 210, 298 225" stroke="#40b0d0" stroke-width="2" fill="none" marker-end="url(#arr)"/>
+ <path d="M240 387 C 290 387, 270 270, 298 255" stroke="#40b0d0" stroke-width="2" fill="none" marker-end="url(#arr)"/>
+
+ <!-- output arrows -->
+ <path d="M440 210 C 480 210, 460 90, 498 88" stroke="#40b0d0" stroke-width="2" fill="none" marker-end="url(#arr)"/>
+ <path d="M440 270 C 480 270, 460 372, 488 374" stroke="#40b0d0" stroke-width="2" fill="none" marker-end="url(#arr)"/>
+
+ <!-- emphasis labels -->
+ <text x="270" y="150" fill="#40b0d0" font-size="10" font-family="monospace" text-anchor="middle">identical results</text>
+ <text x="320" y="462" fill="#aaa" font-size="10" font-family="monospace" text-anchor="middle">headless rendering drives the very same code the window uses — a test render IS the real render</text>
+</svg>
--- /dev/null
+<svg viewBox="0 0 620 300" width="620" height="300" xmlns="http://www.w3.org/2000/svg">
+ <defs>
+ <filter id="glow">
+ <feGaussianBlur stdDeviation="1.5" result="blur"/>
+ <feMerge>
+ <feMergeNode in="blur"/>
+ <feMergeNode in="SourceGraphic"/>
+ </feMerge>
+ </filter>
+ <marker id="arr" viewBox="0 0 8 8" refX="7" refY="4" markerWidth="7" markerHeight="7" orient="auto">
+ <path d="M0 0 L8 4 L0 8 Z" fill="#40b0d0"/>
+ </marker>
+ </defs>
+
+ <rect width="620" height="300" fill="#061018"/>
+ <g stroke="#1a3a4a" stroke-width="0.5">
+ <line x1="0" y1="40" x2="620" y2="40"/><line x1="0" y1="80" x2="620" y2="80"/>
+ <line x1="0" y1="120" x2="620" y2="120"/><line x1="0" y1="160" x2="620" y2="160"/>
+ <line x1="0" y1="200" x2="620" y2="200"/><line x1="0" y1="240" x2="620" y2="240"/>
+ <line x1="0" y1="280" x2="620" y2="280"/>
+ <line x1="40" y1="0" x2="40" y2="300"/><line x1="80" y1="0" x2="80" y2="300"/>
+ <line x1="120" y1="0" x2="120" y2="300"/><line x1="160" y1="0" x2="160" y2="300"/>
+ <line x1="200" y1="0" x2="200" y2="300"/><line x1="240" y1="0" x2="240" y2="300"/>
+ <line x1="280" y1="0" x2="280" y2="300"/><line x1="320" y1="0" x2="320" y2="300"/>
+ <line x1="360" y1="0" x2="360" y2="300"/><line x1="400" y1="0" x2="400" y2="300"/>
+ <line x1="440" y1="0" x2="440" y2="300"/><line x1="480" y1="0" x2="480" y2="300"/>
+ <line x1="520" y1="0" x2="520" y2="300"/><line x1="560" y1="0" x2="560" y2="300"/>
+ <line x1="600" y1="0" x2="600" y2="300"/>
+ </g>
+
+ <!-- fake rendered frame: sentinel background + painted shapes -->
+ <rect x="60" y="40" width="320" height="220" fill="#0a1520" stroke="#40b0d0" stroke-width="2"/>
+ <text x="220" y="32" fill="#40b0d0" font-size="11" font-family="monospace" text-anchor="middle">rendered frame (640×480)</text>
+
+ <!-- painted content: simple house-like blocks -->
+ <rect x="90" y="120" width="80" height="100" fill="rgba(192,80,136,0.55)" stroke="#c05088" stroke-width="1.5"/>
+ <rect x="190" y="80" width="120" height="60" fill="rgba(32,112,192,0.45)" stroke="#2070c0" stroke-width="1.5"/>
+ <rect x="190" y="160" width="150" height="80" fill="rgba(192,80,136,0.35)" stroke="#c05088" stroke-width="1.5"/>
+ <text x="130" y="175" fill="#e090b8" font-size="9" font-family="monospace" text-anchor="middle">painted</text>
+ <text x="255" y="205" fill="#e090b8" font-size="9" font-family="monospace" text-anchor="middle">painted</text>
+
+ <!-- the probed region: relative rect -->
+ <rect x="108" y="139" width="224" height="121" fill="none" stroke="#39FF14" stroke-width="2.5" stroke-dasharray="8 4"/>
+ <text x="338" y="132" fill="#39FF14" font-size="9" font-family="monospace" text-anchor="end" filter="url(#glow)">region (0.15, 0.45) → (0.85, 1.0)</text>
+
+ <!-- a hole: sentinel showing through -->
+ <rect x="225" y="200" width="45" height="30" fill="#000000" stroke="#FF4444" stroke-width="2" stroke-dasharray="4 3"/>
+ <text x="247" y="218" fill="#FF4444" font-size="9" font-family="monospace" text-anchor="middle">hole</text>
+
+ <!-- right: the assertion code and verdict -->
+ <rect x="410" y="60" width="195" height="150" rx="8" fill="rgba(64,176,208,0.08)" stroke="#40b0d0" stroke-width="1.5"/>
+ <text x="508" y="80" fill="#40b0d0" font-size="10" font-family="monospace" text-anchor="middle" filter="url(#glow)">PixelAssertions</text>
+ <text x="420" y="102" fill="#ccc" font-size="9" font-family="monospace">unpaintedFraction(img,</text>
+ <text x="420" y="116" fill="#ccc" font-size="9" font-family="monospace"> bg=0x000000,</text>
+ <text x="420" y="130" fill="#ccc" font-size="9" font-family="monospace"> 0.15, 0.45,</text>
+ <text x="420" y="144" fill="#ccc" font-size="9" font-family="monospace"> 0.85, 1.0)</text>
+ <text x="420" y="168" fill="#999" font-size="9" font-family="monospace">counts pixels that still</text>
+ <text x="420" y="181" fill="#999" font-size="9" font-family="monospace">equal the background</text>
+ <text x="420" y="200" fill="#FF4444" font-size="10" font-family="monospace">→ 0.017 > 0.01 FAIL</text>
+
+ <line x1="380" y1="150" x2="408" y2="140" stroke="#40b0d0" stroke-width="1.5" marker-end="url(#arr)"/>
+
+ <!-- bottom notes -->
+ <text x="60" y="282" fill="#999" font-size="9" font-family="monospace">sentinel background: "nothing rendered here" is unambiguous, even in dark scenes</text>
+</svg>
--- /dev/null
+<svg viewBox="0 0 620 220" width="620" height="220" xmlns="http://www.w3.org/2000/svg">
+ <defs>
+ <filter id="bsp-glow"><feGaussianBlur stdDeviation="1.5" result="b"/><feMerge><feMergeNode in="b"/><feMergeNode in="SourceGraphic"/></feMerge></filter>
+ </defs>
+ <rect width="620" height="220" fill="#061018"/>
+
+ <!-- ── Root node ── -->
+ <rect x="250" y="18" width="120" height="32" rx="4" fill="rgba(64,176,208,0.15)" stroke="#40b0d0" stroke-width="1.5"/>
+ <text x="310" y="39" fill="#40b0d0" font-size="11" font-family="monospace" text-anchor="middle" filter="url(#bsp-glow)">Plane P₁</text>
+
+ <!-- ── Connectors: root → children ── -->
+ <line x1="310" y1="50" x2="310" y2="62" stroke="#40b0d0" stroke-width="1"/>
+ <line x1="310" y1="62" x2="160" y2="62" stroke="#40b0d0" stroke-width="1"/>
+ <line x1="310" y1="62" x2="460" y2="62" stroke="#40b0d0" stroke-width="1"/>
+ <line x1="160" y1="62" x2="160" y2="72" stroke="#40b0d0" stroke-width="1"/>
+ <line x1="460" y1="62" x2="460" y2="72" stroke="#40b0d0" stroke-width="1"/>
+ <!-- Branch labels -->
+ <text x="225" y="58" fill="#30a050" font-size="8" font-family="monospace" text-anchor="middle">front</text>
+ <text x="395" y="58" fill="#d04040" font-size="8" font-family="monospace" text-anchor="middle">back</text>
+
+ <!-- ── Front child ── -->
+ <rect x="100" y="72" width="120" height="32" rx="4" fill="rgba(48,160,80,0.15)" stroke="#30a050" stroke-width="1.5"/>
+ <text x="160" y="93" fill="#30a050" font-size="11" font-family="monospace" text-anchor="middle">Front (P₂)</text>
+
+ <!-- ── Back child ── -->
+ <rect x="400" y="72" width="120" height="32" rx="4" fill="rgba(208,64,64,0.15)" stroke="#d04040" stroke-width="1.5"/>
+ <text x="460" y="93" fill="#d04040" font-size="11" font-family="monospace" text-anchor="middle">Back (P₃)</text>
+
+ <!-- ── Connectors: front child → grandchildren ── -->
+ <line x1="160" y1="104" x2="160" y2="116" stroke="#30a050" stroke-width="1"/>
+ <line x1="160" y1="116" x2="85" y2="116" stroke="#30a050" stroke-width="1"/>
+ <line x1="160" y1="116" x2="235" y2="116" stroke="#30a050" stroke-width="1"/>
+ <line x1="85" y1="116" x2="85" y2="126" stroke="#30a050" stroke-width="1"/>
+ <line x1="235" y1="116" x2="235" y2="126" stroke="#30a050" stroke-width="1"/>
+
+ <!-- ── Leaf nodes ── -->
+ <rect x="45" y="126" width="80" height="28" rx="4" fill="rgba(100,100,100,0.08)" stroke="#aaa" stroke-width="1" stroke-dasharray="3 2"/>
+ <text x="85" y="145" fill="#bbb" font-size="10" font-family="monospace" text-anchor="middle">leaf</text>
+ <rect x="195" y="126" width="80" height="28" rx="4" fill="rgba(100,100,100,0.08)" stroke="#aaa" stroke-width="1" stroke-dasharray="3 2"/>
+ <text x="235" y="145" fill="#bbb" font-size="10" font-family="monospace" text-anchor="middle">leaf</text>
+
+ <!-- ── Explanation ── -->
+ <text x="310" y="185" fill="#ccc" font-size="9" font-family="monospace" text-anchor="middle">Each plane divides space into front (normal side) and back (opposite)</text>
+ <text x="310" y="200" fill="#ccc" font-size="9" font-family="monospace" text-anchor="middle">Polygons are classified and split at each partitioning plane</text>
+</svg>
--- /dev/null
+<svg viewBox="0 0 620 170" width="620" height="170" xmlns="http://www.w3.org/2000/svg">
+ <defs>
+ <filter id="i-glow"><feGaussianBlur stdDeviation="2" result="b"/><feMerge><feMergeNode in="b"/><feMergeNode in="SourceGraphic"/></feMerge></filter>
+ <clipPath id="i-clip-rect"><rect x="370" y="35" width="80" height="80"/></clipPath>
+ <clipPath id="i-clip-circ"><circle cx="450" cy="75" r="42"/></clipPath>
+ </defs>
+ <rect width="620" height="170" fill="#061018"/>
+
+ <!-- ── Input ── -->
+ <text x="110" y="20" fill="#ccc" font-size="11" font-family="monospace" text-anchor="middle">Input</text>
+ <rect x="50" y="35" width="80" height="80" rx="2" fill="rgba(57,255,20,0.2)" stroke="#39FF14" stroke-width="2"/>
+ <text x="90" y="80" fill="#39FF14" font-size="12" font-weight="700" font-family="monospace" text-anchor="middle">A</text>
+ <circle cx="130" cy="75" r="42" fill="rgba(255,102,0,0.2)" stroke="#FF6600" stroke-width="2"/>
+ <text x="148" y="80" fill="#FF6600" font-size="12" font-weight="700" font-family="monospace" text-anchor="middle">B</text>
+
+ <!-- ── Operator ── -->
+ <text x="250" y="70" fill="#40b0d0" font-size="22" font-family="monospace" text-anchor="middle" filter="url(#i-glow)">∩</text>
+ <text x="250" y="92" fill="#40b0d0" font-size="11" font-family="monospace" text-anchor="middle">intersect</text>
+
+ <!-- ── Arrow ── -->
+ <line x1="280" y1="78" x2="330" y2="78" stroke="#40b0d0" stroke-width="1.5" stroke-dasharray="4 3"/>
+ <polygon points="330,73 340,78 330,83" fill="#40b0d0"/>
+
+ <!-- ── Result: only the overlap region ── -->
+ <text x="440" y="20" fill="#ccc" font-size="11" font-family="monospace" text-anchor="middle">Result: A ∩ B</text>
+ <!-- Ghost outlines of original shapes (faint) -->
+ <rect x="370" y="35" width="80" height="80" rx="2" fill="none" stroke="#39FF14" stroke-width="0.5" opacity="0.2" stroke-dasharray="4 3"/>
+ <circle cx="450" cy="75" r="42" fill="none" stroke="#FF6600" stroke-width="0.5" opacity="0.2" stroke-dasharray="4 3"/>
+ <!-- Intersection fill: lens shape = circle arc clipped to rect -->
+ <circle cx="450" cy="75" r="42" fill="rgba(57,255,20,0.08)" stroke="none" clip-path="url(#i-clip-rect)"/>
+ <!-- Left boundary: arc from circle (orange, from B) -->
+ <path d="M450,33 A42,42 0 0,0 450,117" fill="none" stroke="#FF6600" stroke-width="1.5" clip-path="url(#i-clip-rect)"/>
+ <!-- Right boundary: straight edge from rect (green, from A) -->
+ <line x1="450" y1="35" x2="450" y2="115" stroke="#39FF14" stroke-width="1.5" clip-path="url(#i-clip-circ)"/>
+
+ <!-- ── Descriptions ── -->
+ <text x="110" y="142" fill="#ccc" font-size="9" font-family="monospace" text-anchor="middle">Find overlap</text>
+ <text x="110" y="155" fill="#ccc" font-size="9" font-family="monospace" text-anchor="middle">between both</text>
+ <text x="440" y="142" fill="#ccc" font-size="9" font-family="monospace" text-anchor="middle">Only shared volume</text>
+ <text x="440" y="155" fill="#ccc" font-size="9" font-family="monospace" text-anchor="middle">remains</text>
+</svg>
--- /dev/null
+<svg viewBox="0 0 620 170" width="620" height="170" xmlns="http://www.w3.org/2000/svg">
+ <defs>
+ <filter id="s-glow"><feGaussianBlur stdDeviation="2" result="b"/><feMerge><feMergeNode in="b"/><feMergeNode in="SourceGraphic"/></feMerge></filter>
+ <clipPath id="s-cube"><rect x="370" y="35" width="80" height="80"/></clipPath>
+ </defs>
+ <rect width="620" height="170" fill="#061018"/>
+
+ <!-- ── Input ── -->
+ <text x="110" y="20" fill="#aaa" font-size="11" font-family="monospace" text-anchor="middle">Input</text>
+ <rect x="50" y="35" width="80" height="80" rx="2" fill="rgba(57,255,20,0.2)" stroke="#39FF14" stroke-width="2"/>
+ <text x="90" y="80" fill="#39FF14" font-size="12" font-weight="700" font-family="monospace" text-anchor="middle">A</text>
+ <circle cx="130" cy="75" r="42" fill="rgba(255,102,0,0.12)" stroke="#FF6600" stroke-width="2" stroke-dasharray="5 3"/>
+ <text x="148" y="80" fill="#FF6600" font-size="12" font-weight="700" font-family="monospace" text-anchor="middle">B</text>
+
+ <!-- ── Operator ── -->
+ <text x="250" y="70" fill="#40b0d0" font-size="22" font-family="monospace" text-anchor="middle" filter="url(#s-glow)">−</text>
+ <text x="250" y="92" fill="#40b0d0" font-size="11" font-family="monospace" text-anchor="middle">subtract</text>
+
+ <!-- ── Arrow ── -->
+ <line x1="280" y1="78" x2="330" y2="78" stroke="#40b0d0" stroke-width="1.5" stroke-dasharray="4 3"/>
+ <polygon points="330,73 340,78 330,83" fill="#40b0d0"/>
+
+ <!-- ── Result ── -->
+ <text x="440" y="20" fill="#aaa" font-size="11" font-family="monospace" text-anchor="middle">Result: A − B</text>
+ <!-- Cube body -->
+ <rect x="370" y="35" width="80" height="80" rx="2" fill="rgba(57,255,20,0.15)" stroke="#39FF14" stroke-width="1.5"/>
+ <!-- Cavity: dark hole with single solid arc edge -->
+ <circle cx="450" cy="75" r="42" fill="rgba(6,16,24,0.8)" stroke="none" clip-path="url(#s-cube)"/>
+ <path d="M450,33 A42,42 0 0,0 450,117" fill="none" stroke="#FF6600" stroke-width="1.5" clip-path="url(#s-cube)"/>
+ <text x="425" y="78" fill="#40b0d0" font-size="7" font-family="monospace" text-anchor="middle" opacity="0.7">cavity</text>
+
+ <!-- ── Descriptions ── -->
+ <text x="110" y="142" fill="#aaa" font-size="9" font-family="monospace" text-anchor="middle">B is the "cutter"</text>
+ <text x="110" y="155" fill="#aaa" font-size="9" font-family="monospace" text-anchor="middle">carves out of A</text>
+ <text x="440" y="142" fill="#aaa" font-size="9" font-family="monospace" text-anchor="middle">Cube with cavity</text>
+ <text x="440" y="155" fill="#aaa" font-size="9" font-family="monospace" text-anchor="middle">interior faces visible</text>
+</svg>
--- /dev/null
+<svg viewBox="0 0 620 170" width="620" height="170" xmlns="http://www.w3.org/2000/svg">
+ <defs>
+ <filter id="u-glow"><feGaussianBlur stdDeviation="2" result="b"/><feMerge><feMergeNode in="b"/><feMergeNode in="SourceGraphic"/></feMerge></filter>
+ </defs>
+ <rect width="620" height="170" fill="#061018"/>
+
+ <!-- ── Input ── -->
+ <text x="110" y="20" fill="#ccc" font-size="11" font-family="monospace" text-anchor="middle">Input</text>
+ <rect x="50" y="35" width="80" height="80" rx="2" fill="rgba(57,255,20,0.2)" stroke="#39FF14" stroke-width="2"/>
+ <text x="90" y="80" fill="#39FF14" font-size="12" font-weight="700" font-family="monospace" text-anchor="middle">A</text>
+ <circle cx="130" cy="75" r="42" fill="rgba(255,102,0,0.2)" stroke="#FF6600" stroke-width="2"/>
+ <text x="148" y="80" fill="#FF6600" font-size="12" font-weight="700" font-family="monospace" text-anchor="middle">B</text>
+
+ <!-- ── Operator ── -->
+ <text x="250" y="70" fill="#40b0d0" font-size="22" font-family="monospace" text-anchor="middle" filter="url(#u-glow)">+</text>
+ <text x="250" y="92" fill="#40b0d0" font-size="11" font-family="monospace" text-anchor="middle">union</text>
+
+ <!-- ── Arrow ── -->
+ <line x1="280" y1="78" x2="330" y2="78" stroke="#40b0d0" stroke-width="1.5" stroke-dasharray="4 3"/>
+ <polygon points="330,73 340,78 330,83" fill="#40b0d0"/>
+
+ <!-- ── Result ── -->
+ <text x="440" y="20" fill="#ccc" font-size="11" font-family="monospace" text-anchor="middle">Result: A + B</text>
+ <!-- Merged outer boundary: cube left + top + circle right + cube bottom -->
+ <path d="M370,35 L370,115 L450,115 L450,103 A42,42 0 0,0 450,47 L450,35 Z"
+ fill="rgba(57,255,20,0.12)" stroke="#39FF14" stroke-width="1.5"/>
+ <path d="M450,47 A42,42 0 0,1 450,103"
+ fill="rgba(255,102,0,0.12)" stroke="#FF6600" stroke-width="1.5"/>
+ <!-- Interior seam removed indicator -->
+ <line x1="450" y1="47" x2="450" y2="103" stroke="#40b0d0" stroke-width="1" stroke-dasharray="3 2" opacity="0.5"/>
+ <text x="458" y="78" fill="#40b0d0" font-size="7" font-family="monospace" opacity="0.7">removed</text>
+
+ <!-- ── Descriptions ── -->
+ <text x="110" y="142" fill="#ccc" font-size="9" font-family="monospace" text-anchor="middle">Keeps all geometry</text>
+ <text x="110" y="155" fill="#ccc" font-size="9" font-family="monospace" text-anchor="middle">from both shapes</text>
+ <text x="440" y="142" fill="#ccc" font-size="9" font-family="monospace" text-anchor="middle">Single combined volume</text>
+ <text x="440" y="155" fill="#ccc" font-size="9" font-family="monospace" text-anchor="middle">interior faces removed</text>
+</svg>
--- /dev/null
+<svg viewBox="0 0 620 190" width="620" height="190" xmlns="http://www.w3.org/2000/svg">
+ <defs>
+ <filter id="c-glow"><feGaussianBlur stdDeviation="1.5" result="b"/><feMerge><feMergeNode in="b"/><feMergeNode in="SourceGraphic"/></feMerge></filter>
+ </defs>
+ <rect width="620" height="190" fill="#061018"/>
+
+ <!-- ── Original polygon crossing a plane ── -->
+ <text x="120" y="20" fill="#ccc" font-size="11" font-family="monospace" text-anchor="middle">Polygon crosses plane</text>
+ <polygon points="60,50 180,50 120,140" fill="rgba(32,112,192,0.15)" stroke="#2070c0" stroke-width="1.5"/>
+ <line x1="30" y1="70" x2="210" y2="110" stroke="#40b0d0" stroke-width="2" filter="url(#c-glow)"/>
+ <text x="38" y="64" fill="#40b0d0" font-size="9" font-family="monospace">plane</text>
+ <circle cx="81" cy="81" r="3.5" fill="#40b0d0"/>
+ <circle cx="149" cy="96" r="3.5" fill="#40b0d0"/>
+
+ <!-- ── Arrow ── -->
+ <text x="268" y="85" fill="#40b0d0" font-size="18" font-family="monospace" text-anchor="middle" filter="url(#c-glow)">→</text>
+ <text x="268" y="105" fill="#40b0d0" font-size="10" font-family="monospace" text-anchor="middle">split</text>
+
+ <!-- ── Split result ── -->
+ <text x="460" y="20" fill="#ccc" font-size="11" font-family="monospace" text-anchor="middle">Split into fragments</text>
+ <line x1="370" y1="70" x2="550" y2="110" stroke="#40b0d0" stroke-width="0.7" opacity="0.25" stroke-dasharray="4 3"/>
+
+ <!-- Front fragment (above plane) — trapezoid -->
+ <polygon points="400,50 520,50 489,96 421,81" fill="rgba(48,160,80,0.15)" stroke="#30a050" stroke-width="1.5"/>
+ <text x="458" y="68" fill="#30a050" font-size="9" font-family="monospace" text-anchor="middle">front</text>
+
+ <!-- Back fragment (below plane) — triangle -->
+ <polygon points="421,81 489,96 460,140" fill="rgba(208,64,64,0.15)" stroke="#d04040" stroke-width="1.5"/>
+ <text x="457" y="115" fill="#d04040" font-size="9" font-family="monospace" text-anchor="middle">back</text>
+
+ <!-- New edge at split -->
+ <line x1="421" y1="81" x2="489" y2="96" stroke="#40b0d0" stroke-width="1.5" stroke-dasharray="4 2"/>
+ <circle cx="421" cy="81" r="3.5" fill="#40b0d0"/>
+ <circle cx="489" cy="96" r="3.5" fill="#40b0d0"/>
+ <text x="470" y="78" fill="#40b0d0" font-size="7" font-family="monospace" text-anchor="middle" opacity="0.8">new edge</text>
+
+ <!-- ── Explanation ── -->
+ <text x="310" y="172" fill="#ccc" font-size="9" font-family="monospace" text-anchor="middle">Spanning polygons are split; each fragment goes to its respective subtree</text>
+</svg>
--- /dev/null
+#+SETUPFILE: ~/.emacs.d/org-styles/html/darksun.theme
+#+TITLE: Constructive Solid Geometry - Aukio 3D
+#+LANGUAGE: en
+#+LATEX_HEADER: \usepackage[margin=1.0in]{geometry}
+#+LATEX_HEADER: \usepackage{parskip}
+#+LATEX_HEADER: \usepackage[none]{hyphenat}
+
+#+OPTIONS: H:20 num:20
+#+OPTIONS: author:nil
+
+#+HTML_HEAD: <link rel="stylesheet" href="../style.css"/>
+
+[[file:../index.html#outline-container-understanding-3d-engine][<- Back to index]]
+
+* What is CSG?
+:PROPERTIES:
+:CUSTOM_ID: what-is-csg
+:ID: a1b2c3d4-e5f6-7890-abcd-ef1234567890
+:END:
+
+*Constructive Solid Geometry* (CSG) is a modeling technique that builds
+complex 3D shapes by combining simpler primitives using boolean
+operations. Instead of manually creating every vertex and face, you
+define shapes as the result of operations like "merge these two cubes"
+or "carve a hole using this sphere."
+
+CSG is particularly powerful for:
+- *Procedural modeling* — generate complex geometry algorithmically
+- *CAD/CAM applications* — define parts as combinations of primitives
+- *Game development* — create architectural elements, holes, cavities
+- *Rapid prototyping* — iterate on designs by adjusting operations
+
+The three fundamental CSG operations are:
+
+| Operation | Symbol | Result |
+|-------------+--------+-------------------------------------------|
+| Subtract | A - B | A with B carved out (holes, cavities) |
+| Union | A + B | Combined volume (both shapes merged) |
+| Intersect | A ∩ B | Volume where both overlap |
+
+See the [[https://www3.svjatoslav.eu/projects/aukio-3d-demos/#csg-demo][CSG demo]] for an interactive visualization.
+
+* The Three Operations
+:PROPERTIES:
+:CUSTOM_ID: the-three-operations
+:END:
+
+#+attr_html: :class responsive-img
+#+attr_latex: :width 1000px
+[[https://www3.svjatoslav.eu/projects/aukio-3d-demos/#csg-demo][file:CSG%20demo.png]]
+
+The screenshot above shows all three operations displayed left to right:
+subtract (green cube with spherical cavity), union (merged green and
+orange shapes), and intersect (only the overlapping region in blue).
+
+The diagrams below use the same green cube (A) and orange sphere (B) as
+the screenshot above. Each operation transforms these inputs differently,
+producing the results shown from left to right in the image.
+
+** Subtract (A - B)
+:PROPERTIES:
+:CUSTOM_ID: subtract-operation
+:END:
+
+#+INCLUDE: "CSG operations.svg" export html
+
+*Subtract* removes the orange sphere (B) from the green cube (A), carving
+out a cavity. The diagram shows B acting as a "cutter" — where it overlaps
+A, a hole is created. Interior faces *are preserved* and become visible,
+allowing you to see inside the carved-out space (shown as the orange dashed
+curve in the result).
+
+This matches the leftmost shape in the screenshot: a green cube with a
+visible spherical hollow inside, showing the interior surfaces created by
+the subtraction.
+
+This operation is ideal for creating:
+- Holes and tunnels
+- Carved-out spaces
+- Hollow objects
+
+#+BEGIN_SRC java
+SolidPolygonCube cube = new SolidPolygonCube(Point3D.origin(), 80, Color.GREEN);
+SolidPolygonSphere sphere = new SolidPolygonSphere(Point3D.origin(), 60, 8, Color.ORANGE);
+
+cube.subtract(sphere); // cube now has a spherical cavity
+#+END_SRC
+
+** Union (A + B)
+:PROPERTIES:
+:CUSTOM_ID: union-operation
+:END:
+
+#+INCLUDE: "CSG union.svg" export html
+
+*Union* merges the green cube (A) and orange sphere (B) into one continuous
+volume. The diagram shows both shapes combining — the interior seam (where
+they overlap) is removed, creating a single solid surface with no internal
+boundaries (indicated by the dashed blue line labeled "removed").
+
+This corresponds to the center shape in the screenshot: both green and
+orange colors present but seamlessly joined, forming one unified object.
+
+#+BEGIN_SRC java
+SolidPolygonCube cube = new SolidPolygonCube(Point3D.origin(), 80, Color.GREEN);
+SolidPolygonSphere sphere = new SolidPolygonSphere(Point3D.origin(), 60, 8, Color.ORANGE);
+
+cube.union(sphere); // cube now contains the merged result
+#+END_SRC
+
+** Intersect (A ∩ B)
+:PROPERTIES:
+:CUSTOM_ID: intersect-operation
+:END:
+
+#+INCLUDE: "CSG intersect.svg" export html
+
+*Intersect* keeps only the volume where the green cube (A) and orange
+sphere (B) overlap — the region that is inside *both* shapes
+simultaneously. The diagram shows this as the blue-shaded area: the
+portion of the sphere that fits within the cube boundaries. Everything
+else is discarded.
+
+This is the rightmost shape in the screenshot: only the overlapping
+portion remains, showing which parts of space were occupied by both the
+cube and sphere at the same time.
+
+This operation is useful for:
+- Creating shapes constrained by multiple boundaries
+- Finding collision regions
+- Trimming geometry to fit within bounds
+
+#+BEGIN_SRC java
+SolidPolygonCube cube = new SolidPolygonCube(Point3D.origin(), 80, Color.GREEN);
+SolidPolygonSphere sphere = new SolidPolygonSphere(Point3D.origin(), 60, 8, Color.ORANGE);
+
+cube.intersect(sphere); // only the overlapping region remains
+#+END_SRC
+
+* BSP Tree Algorithm
+:PROPERTIES:
+:CUSTOM_ID: bsp-tree-algorithm
+:END:
+
+CSG boolean operations are implemented using *Binary Space Partitioning*
+(BSP) trees. A BSP tree recursively divides 3D space using planes,
+creating a hierarchical structure that enables efficient polygon clipping
+and spatial queries.
+
+** BSP Tree Structure
+:PROPERTIES:
+:CUSTOM_ID: bsp-tree-structure
+:END:
+
+#+INCLUDE: "BSP tree.svg" export html
+
+Each BSP node contains:
+- A *partitioning plane* that divides space into two half-spaces
+- *Polygons* that lie exactly on this plane (coplanar)
+- *Front* subtree — polygons on the same side as the plane's normal
+- *Back* subtree — polygons on the opposite side
+
+** Key BSP Operations
+:PROPERTIES:
+:CUSTOM_ID: key-bsp-operations
+:END:
+
+The BSP tree provides three core operations that enable CSG:
+
+| Operation | Description |
+|----------------+--------------------------------------------------|
+| =invert()= | Flip all normals, swap front/back children |
+| =clipTo(tree)= | Remove polygons inside the other tree's solid |
+| =addPolygons()= | Insert new polygons, splitting at planes |
+
+*Invert* is fundamental to CSG. By flipping inside/outside, we can
+transform subtraction and intersection into variations of clipping:
+
+- **Subtract** = invert A, clip against B, add B's clipped parts, invert back
+- **Intersect** = invert A, clip B against A, invert B, clip A against B, combine, invert A back
+
+** Polygon Clipping
+:PROPERTIES:
+:CUSTOM_ID: polygon-clipping
+:END:
+
+When a polygon crosses a partitioning plane, it's *split* into two
+fragments:
+
+#+INCLUDE: "Polygon clipping.svg" export html
+
+This recursive splitting ensures that all polygons are cleanly classified
+as entirely in front, entirely behind, or exactly on a plane — never
+"spanning" across.
+
+* Using CSG in Aukio 3D
+:PROPERTIES:
+:CUSTOM_ID: using-csg-in-aukio-3d
+:END:
+
+CSG operations are methods on [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/composite/base/AbstractCompositeShape.html][AbstractCompositeShape]]. They modify the
+shape *in-place* — the result replaces the original geometry.
+
+** Basic Usage
+:PROPERTIES:
+:CUSTOM_ID: basic-usage
+:END:
+
+#+BEGIN_SRC java
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.solid.*;
+
+// Create two shapes
+SolidPolygonCube cube = new SolidPolygonCube(Point3D.origin(), 100, Color.GREEN);
+SolidPolygonSphere sphere = new SolidPolygonSphere(Point3D.origin(), 70, 12, Color.ORANGE);
+
+// Perform CSG operations (in-place modification)
+cube.subtract(sphere); // Cube with spherical cavity
+// or
+cube.union(sphere); // Merged shape
+// or
+cube.intersect(sphere); // Only overlapping region
+
+// Add to scene
+shapes.addShape(cube.setBackfaceCulling(true));
+#+END_SRC
+
+** Child Handling Behavior
+:PROPERTIES:
+:CUSTOM_ID: child-handling
+:END:
+
+CSG operations only affect *SolidPolygon* geometry. Other children are
+preserved as objects:
+
+| Child Type | Union | Subtract | Intersect |
+|-----------------------+------------------+------------------+------------------|
+| SolidPolygon (this) | Replaced with result | Replaced with result | Replaced with result |
+| SolidPolygon (other) | Merged into result | Discarded (cutter) | Discarded |
+| Line, TextCanvas (this) | Preserved | Preserved | Preserved |
+| Line, TextCanvas (other) | Merged into this shape | Discarded | Discarded |
+| Nested composite | Preserved as object — but see below | same | same |
+
+*Nested composites are not CSG-safe.* Polygon extraction recurses into
+them, so their SolidPolygons are included in the BSP result — while the
+nested composite object itself is also preserved, duplicating that
+geometry in the render. Apply CSG to flat composites, or extract the
+nested polygons first.
+
+This allows you to attach labels, decorations, or wireframe overlays to
+shapes without them being affected by CSG operations (for union, the
+other shape's decorations are copied over too).
+
+** Important Notes
+:PROPERTIES:
+:CUSTOM_ID: important-notes
+:END:
+
+1. *Shapes are modified in-place*. The original geometry is replaced.
+ Clone shapes beforehand if you need to preserve the originals.
+
+2. *CSG works on SolidPolygon children only*. TexturedTriangle and other
+ shape types are not processed.
+
+3. *Result quality depends on mesh density*. Low-polygon inputs may
+ produce visible artifacts at intersection boundaries. Use higher
+ subdivision counts for smoother results.
+
+4. *Backface culling is recommended*. CSG results often have internal
+ faces from the cutting operation. Enable culling to hide backfaces:
+ =shape.setBackfaceCulling(true)=
+
+* Related Classes
+:PROPERTIES:
+:CUSTOM_ID: related-classes
+:END:
+
+| Class | Purpose |
+|--------------------------+------------------------------------------------------|
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/geometry/BspTree.html][BspTree]] | BSP tree for spatial partitioning and CSG operations |
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/geometry/Plane.html][Plane]] | Partitioning plane used by BSP nodes |
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/basic/solidpolygon/SolidPolygon.html][SolidPolygon]] | Polygon shape processed by CSG |
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/composite/base/AbstractCompositeShape.html][AbstractCompositeShape]] | Base class with union/subtract/intersect methods |
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/composite/solid/SolidPolygonMesh.html][SolidPolygonMesh]] | Custom polygon mesh for arbitrary geometry |
+| SolidPolygon* primitives | See [[https://www3.svjatoslav.eu/projects/aukio-3d-demos/#shape-gallery][Shape Gallery]] for all available shapes |
--- /dev/null
+<svg viewBox="0 0 640 520" width="640" height="520" xmlns="http://www.w3.org/2000/svg">
+ <rect width="640" height="520" fill="#061018"/>
+ <circle cx="280" cy="260" r="10" fill="rgba(80,96,192,0.1)" stroke="rgba(80,96,192,0.3)" stroke-width="2"/>
+ <line x1="280" y1="260" x2="560" y2="260" stroke="#d04040" stroke-width="5"/>
+ <polygon points="560,260 540,250 540,270" fill="#d04040"/>
+ <text x="568" y="268" fill="#d04040" font-size="28" font-weight="700" font-family="monospace">X</text>
+ <text x="400" y="304" fill="#bbb" font-size="18" font-family="monospace">right (+) / left (-)</text>
+ <line x1="280" y1="260" x2="280" y2="480" stroke="#30a050" stroke-width="5"/>
+ <polygon points="280,480 270,460 290,460" fill="#30a050"/>
+ <text x="292" y="504" fill="#30a050" font-size="28" font-weight="700" font-family="monospace">Y</text>
+ <text x="292" y="456" fill="#bbb" font-size="18" font-family="monospace">down (+) / up (-)</text>
+ <line x1="280" y1="260" x2="120" y2="140" stroke="#2070c0" stroke-width="5"/>
+ <polygon points="120,140 140,144 132,164" fill="#2070c0"/>
+ <text x="84" y="124" fill="#2070c0" font-size="28" font-weight="700" font-family="monospace">Z</text>
+ <text x="120" y="112" fill="#bbb" font-size="18" font-family="monospace">away (+) / towards (-)</text>
+ <text x="300" y="204" fill="#aaa" font-size="22" font-weight="600" font-family="monospace">Origin</text>
+ <text x="294" y="230" fill="#bbb" font-size="18" font-family="monospace">(0, 0, 0)</text>
+</svg>
\ No newline at end of file
--- /dev/null
+#+SETUPFILE: ~/.emacs.d/org-styles/html/darksun.theme
+#+TITLE: Depth Buffer - Aukio 3D
+#+LANGUAGE: en
+#+LATEX_HEADER: \usepackage[margin=1.0in]{geometry}
+#+LATEX_HEADER: \usepackage{parskip}
+#+LATEX_HEADER: \setlength{\parindent}{15pt}
+#+LATEX_HEADER: \usepackage{palatino}
+#+LATEX_HEADER: \usepackage{charter}
+#+HTML_HEAD: <style type="text/css">body { max-width: 100%;}</style>
+
+[[file:../index.html#outline-container-depth-buffer][<- Back to index]]
+
+* Per-pixel visibility
+:PROPERTIES:
+:CUSTOM_ID: per-pixel
+:END:
+
+The engine resolves visibility with a depth buffer, not paint order.
+Every rasterized triangle carries a per-pixel depth quantity =zw =
+1/z= (camera-space), interpolated linearly across each span — =1/z= is
+affine in screen space, so it rides the same edge interpolators as the
+texture gradients. A fragment wins a pixel only where
+
+#+BEGIN_EXAMPLE
+zw > stored - margin * zw^2 (margin = 0 by default)
+#+END_EXAMPLE
+
+Default margin 0 is *strict depth*: the nearer fragment always wins,
+regardless of paint order, so overlapping depth ranges — a floor tile
+extending under furniture, a wall seen through a doorway — come out
+correct per pixel. A nonzero margin (= RenderingContext.DEPTH_MARGIN_DZ =,
+=-Daukio.zbuffer.margin=, world units) re-opens a tolerance window
+*behind* the stored depth for near-coplanar pairs; any nonzero window
+re-imports per-triangle sort errors into per-pixel occlusion, which is
+why the default is strict.
+
+The depth buffer is allocated once per frame context
+(=RenderingContext.depth=, float per pixel) and cleared per tile
+together with the pixel buffer.
+
+* Two passes
+:PROPERTIES:
+:CUSTOM_ID: two-passes
+:END:
+
+=RenderAggregator.paintSorted= paints the sorted queue in two passes:
+
+1. *Opaque pass* — opaque-class triangles, iterated front-to-back (the
+ queue is back-to-front, so reversed), depth test + depth write.
+ Front-to-back order is a pure performance hint: hidden fragments
+ die on the depth test *before* the texture fetch (early-z).
+2. *Alpha pass* — alpha-class triangles (translucent solid polygons,
+ alpha-carrying textures, SDF text), iterated back-to-front in queue
+ order, depth test but *no depth write*. Translucency never
+ occludes, and overlapping translucent surfaces keep painter-coherent
+ mutual order.
+
+A shape's class comes from its paint color or texture: solid polygons
+with =alpha = 255= are opaque, anything translucent is alpha-class;
+textured triangles are alpha-class when the texture has alpha or is an
+SDF mask.
+
+* Which shapes carry depth
+:PROPERTIES:
+:CUSTOM_ID: shapes
+:END:
+
+- =TexturedTriangle= — opaque or alpha class by texture.
+- =SolidPolygon= — depth-tested since 2026-09-17; opaque when its
+ (possibly shaded) color is fully opaque, translucent otherwise.
+ Near-plane-clipped quads fan-triangulate with depth like any other
+ triangles.
+- =LightmappedTriangle= — a textured triangle, so the same rules.
+- =Line=, =Billboard=, =GlowingPoint= — no depth by design: they are
+ 2D overlays (wireframes, markers, sprites) and always paint on top,
+ in the alpha pass.
+
+Because every occluder writes depth, scene code no longer needs any
+ordering structure: composites just fan-triangulate their polygons.
+(=LightmappedCompositeShape= exists only to wrap polygons as lightmap
+carriers for the GI system, not to order them.)
+
+* Hi-Z occlusion pyramid
+:PROPERTIES:
+:CUSTOM_ID: hi-z
+:END:
+
+After each successful paint, =ViewPanel= builds a Hi-Z pyramid from
+the depth buffer (gui/HiZPyramid): 8-pixel tiles pooled upward,
+each tile storing the *minimum* =zw= (farthest written depth —
+max-pooling would store the nearest occluder and wrongly cull geometry
+visible between near gaps). Next frame, =TriangleMeshBlock= projects
+its world AABB's 8 corners and, when the nearest corner is still
+behind the pyramid's stored depth, skips the whole block before any
+per-triangle work.
+
+The test is conservative by construction (min-pooling plus sky pixels
+at =-inf=), so it never culls visible geometry; wrong culls under
+camera motion self-heal in one frame. Knobs: =-Daukio.hiz.margin=0.02=,
+kill switch =-Daukio.hiz=false=. Headless snapshots never build the
+pyramid, so golden renders are structurally unaffected. Stereo skips
+the test (the pyramid is mono).
+
+* Determinism and depth dumps
+:PROPERTIES:
+:CUSTOM_ID: determinism
+:END:
+
+The renderer is bit-deterministic: same scene and camera give
+bit-identical pixels across runs, which is what the golden-image
+regression tests compare. =Snapshot= (the headless toolkit) supports
+=-Daukio.zbuffer.dumpDepth=path.png= to write a grayscale depth map
+alongside the color image — useful when hunting depth-window bugs
+(bisect those with =-Daukio.zbuffer.margin=0=).
+
+* Related classes
+:PROPERTIES:
+:CUSTOM_ID: related-classes
+:END:
+
+| Class | Role |
+|----------------------+----------------------------------------------------------|
+| =RenderingContext= | =depth= buffer, =depthPass=, =DEPTH_MARGIN_DZ= constant |
+| =RenderAggregator= | =paintSorted= two-pass driver, queue sort |
+| =TexturedTriangle= | Z span writers (perspective and affine) |
+| =SolidPolygon= | flat-color Z span writer, two-pass classification |
+| =HiZPyramid= | temporal whole-block occlusion culling |
+| =ViewPanel= | per-tile depth clear, pyramid rebuild after paint |
+
+[[file:../index.html#outline-container-depth-buffer][Back to main documentation]]
--- /dev/null
+<svg viewBox="0 0 640 480" width="640" height="480" xmlns="http://www.w3.org/2000/svg">
+ <rect width="640" height="480" fill="#061018"/>
+ <polygon points="320,100 160,380 480,380" fill="rgba(100,100,200,0.04)" stroke="rgba(100,100,200,0.2)" stroke-width="2"/>
+ <line x1="320" y1="100" x2="480" y2="380" stroke="#5060c0" stroke-width="6" stroke-linecap="round"/>
+ <circle cx="320" cy="100" r="10" fill="#5060c0"/>
+ <circle cx="160" cy="380" r="8" fill="rgba(80,96,192,0.5)"/>
+ <circle cx="480" cy="380" r="10" fill="#5060c0"/>
+ <text x="300" y="80" fill="#aaa" font-size="20" font-family="monospace">V₁</text>
+ <text x="492" y="388" fill="#aaa" font-size="20" font-family="monospace">V₂</text>
+ <text x="120" y="400" fill="#bbb" font-size="20" font-family="monospace">V₃</text>
+ <text x="420" y="220" fill="#5060c0" font-size="24" font-weight="700" font-family="monospace" transform="rotate(30 420 220)">edge</text>
+</svg>
--- /dev/null
+<svg viewBox="0 0 640 480" width="640" height="480" xmlns="http://www.w3.org/2000/svg">
+ <rect width="640" height="480" fill="#061018"/>
+ <polygon points="320,80 120,400 520,400" fill="rgba(200,80,140,0.15)" stroke="#c05088" stroke-width="3"/>
+ <line x1="200" y1="280" x2="440" y2="280" stroke="rgba(200,80,140,0.1)" stroke-width="1"/>
+ <line x1="240" y1="320" x2="400" y2="320" stroke="rgba(200,80,140,0.08)" stroke-width="1"/>
+ <line x1="164" y1="360" x2="476" y2="360" stroke="rgba(200,80,140,0.06)" stroke-width="1"/>
+ <circle cx="320" cy="80" r="8" fill="#c05088"/>
+ <circle cx="120" cy="400" r="8" fill="#c05088"/>
+ <circle cx="520" cy="400" r="8" fill="#c05088"/>
+ <text x="296" y="60" fill="#c05088" font-size="20" font-weight="700" font-family="monospace">V₁</text>
+ <text x="76" y="420" fill="#c05088" font-size="20" font-weight="700" font-family="monospace">V₂</text>
+ <text x="532" y="420" fill="#c05088" font-size="20" font-weight="700" font-family="monospace">V₃</text>
+ <text x="264" y="300" fill="rgba(192,80,136,0.5)" font-size="28" font-weight="700" font-family="monospace">FACE</text>
+</svg>
--- /dev/null
+<svg viewBox="0 0 620 300" width="620" height="300" xmlns="http://www.w3.org/2000/svg">
+ <defs>
+ <filter id="f-glow"><feGaussianBlur stdDeviation="2" result="b"/><feMerge><feMergeNode in="b"/><feMergeNode in="SourceGraphic"/></feMerge></filter>
+ </defs>
+ <rect width="620" height="300" fill="#061018"/>
+
+ <!-- Z axis -->
+ <line x1="60" y1="150" x2="590" y2="150" stroke="rgba(32,112,192,0.2)" stroke-width="1" stroke-dasharray="6 3"/>
+ <text x="570" y="143" fill="#2070c0" font-size="11" font-weight="700" font-family="monospace">+Z</text>
+ <text x="530" y="163" fill="#999" font-size="8" font-family="monospace">(view direction)</text>
+
+ <!-- Camera -->
+ <circle cx="60" cy="150" r="7" fill="rgba(32,112,192,0.3)" stroke="#2070c0" stroke-width="2" filter="url(#f-glow)"/>
+ <text x="74" y="154" fill="#2070c0" font-size="12" font-weight="700" font-family="monospace">Camera</text>
+
+ <!-- Frustum edges: camera → near corners -->
+ <line x1="60" y1="150" x2="170" y2="105" stroke="rgba(48,160,80,0.3)" stroke-width="1"/>
+ <line x1="60" y1="150" x2="170" y2="195" stroke="rgba(48,160,80,0.3)" stroke-width="1"/>
+ <!-- Frustum edges: near → far corners -->
+ <line x1="170" y1="105" x2="440" y2="40" stroke="rgba(48,160,80,0.25)" stroke-width="1"/>
+ <line x1="170" y1="195" x2="440" y2="260" stroke="rgba(48,160,80,0.25)" stroke-width="1"/>
+ <!-- Extended rays behind far (faint dashed) -->
+ <line x1="440" y1="40" x2="520" y2="10" stroke="rgba(48,160,80,0.1)" stroke-width="1" stroke-dasharray="3 3"/>
+ <line x1="440" y1="260" x2="520" y2="290" stroke="rgba(48,160,80,0.1)" stroke-width="1" stroke-dasharray="3 3"/>
+
+ <!-- Near plane -->
+ <rect x="168" y="105" width="4" height="90" rx="1" fill="rgba(48,160,80,0.25)" stroke="#30a050" stroke-width="1.5"/>
+ <text x="155" y="96" fill="#30a050" font-size="10" font-family="monospace" font-weight="700">Near</text>
+
+ <!-- Far plane -->
+ <rect x="438" y="40" width="4" height="220" rx="1" fill="rgba(48,160,80,0.15)" stroke="#30a050" stroke-width="1.5"/>
+ <text x="425" y="32" fill="#30a050" font-size="10" font-family="monospace" font-weight="700">Far</text>
+
+ <!-- Frustum fill (the visible volume) -->
+ <polygon points="170,105 170,195 440,260 440,40" fill="rgba(48,160,80,0.06)" stroke="none"/>
+
+ <!-- Visible region label -->
+ <text x="290" y="145" fill="#30a050" font-size="11" font-weight="700" font-family="monospace" text-anchor="middle" opacity="0.6">visible region</text>
+
+ <!-- Plane labels along frustum edges -->
+ <text x="295" y="62" fill="#999" font-size="8" font-family="monospace" text-anchor="middle">Top plane</text>
+ <text x="295" y="242" fill="#999" font-size="8" font-family="monospace" text-anchor="middle">Bottom plane</text>
+
+ <!-- Object inside frustum (rendered) -->
+ <rect x="270" y="130" width="28" height="28" rx="2" fill="rgba(48,160,80,0.2)" stroke="#30a050" stroke-width="1.5"/>
+ <text x="276" y="150" fill="#30a050" font-size="14" font-family="monospace">✓</text>
+ <text x="258" y="172" fill="#30a050" font-size="8" font-family="monospace">rendered</text>
+
+ <!-- Object outside frustum (culled — above) -->
+ <rect x="480" y="18" width="24" height="24" rx="2" fill="rgba(208,64,64,0.12)" stroke="rgba(208,64,64,0.5)" stroke-width="1.5" stroke-dasharray="3 2"/>
+ <text x="485" y="36" fill="rgba(208,64,64,0.8)" font-size="13" font-family="monospace">✗</text>
+ <text x="470" y="52" fill="rgba(208,64,64,0.6)" font-size="8" font-family="monospace">culled</text>
+
+ <!-- Object outside frustum (culled — below) -->
+ <rect x="310" y="266" width="24" height="24" rx="2" fill="rgba(208,64,64,0.12)" stroke="rgba(208,64,64,0.5)" stroke-width="1.5" stroke-dasharray="3 2"/>
+ <text x="315" y="284" fill="rgba(208,64,64,0.8)" font-size="13" font-family="monospace">✗</text>
+ <text x="300" y="300" fill="rgba(208,64,64,0.6)" font-size="8" font-family="monospace">culled</text>
+</svg>
--- /dev/null
+<svg viewBox="0 0 520 200" width="520" height="200" xmlns="http://www.w3.org/2000/svg">
+ <defs>
+ <filter id="p-glow"><feGaussianBlur stdDeviation="1.5" result="b"/><feMerge><feMergeNode in="b"/><feMergeNode in="SourceGraphic"/></feMerge></filter>
+ </defs>
+ <rect width="520" height="200" fill="#061018"/>
+
+ <!-- Explanation text -->
+ <text x="30" y="22" fill="#aaa" font-size="10" font-family="monospace">P-vertex: corner most aligned with plane normal</text>
+ <text x="30" y="36" fill="#bbb" font-size="9" font-family="monospace">If P is behind the plane → entire AABB is outside</text>
+
+ <!-- Frustum plane (diagonal line) -->
+ <line x1="50" y1="170" x2="430" y2="55" stroke="#b09020" stroke-width="2" filter="url(#p-glow)"/>
+ <text x="432" y="52" fill="#b09020" font-size="10" font-weight="700" font-family="monospace">Plane</text>
+
+ <!-- "inside" region label -->
+ <text x="100" y="80" fill="rgba(48,160,80,0.4)" font-size="10" font-family="monospace">inside frustum</text>
+ <!-- "outside" region label -->
+ <text x="310" y="170" fill="rgba(208,64,64,0.4)" font-size="10" font-family="monospace">outside frustum</text>
+
+ <!-- Normal vector arrow -->
+ <line x1="270" y1="100" x2="230" y2="78" stroke="#b09020" stroke-width="1.5"/>
+ <polygon points="230,78 237,76 236,83" fill="#b09020"/>
+ <text x="222" y="72" fill="#b09020" font-size="9" font-family="monospace" font-weight="700">N</text>
+
+ <!-- AABB inside frustum (fully visible) -->
+ <rect x="80" y="100" width="60" height="50" rx="2" fill="rgba(48,160,80,0.15)" stroke="#30a050" stroke-width="1.5"/>
+ <text x="97" y="130" fill="#30a050" font-size="9" font-family="monospace" text-anchor="middle">inside</text>
+ <!-- P-vertex for inside box (top-right corner, closest to plane) -->
+ <circle cx="140" cy="100" r="3.5" fill="#30a050"/>
+ <text x="145" y="97" fill="#30a050" font-size="7" font-family="monospace">P</text>
+
+ <!-- AABB outside frustum (fully culled) -->
+ <rect x="340" y="110" width="60" height="50" rx="2" fill="rgba(208,64,64,0.12)" stroke="rgba(208,64,64,0.5)" stroke-width="1.5" stroke-dasharray="3 2"/>
+ <text x="356" y="140" fill="rgba(208,64,64,0.7)" font-size="9" font-family="monospace" text-anchor="middle">outside</text>
+ <!-- P-vertex for outside box (top-left corner, closest to plane) -->
+ <circle cx="340" cy="110" r="3.5" fill="rgba(208,64,64,0.8)"/>
+ <text x="327" y="107" fill="rgba(208,64,64,0.8)" font-size="7" font-family="monospace">P</text>
+</svg>
--- /dev/null
+#+SETUPFILE: ~/.emacs.d/org-styles/html/darksun.theme
+#+TITLE: Frustum & View Frustum Culling - Aukio 3D
+#+LANGUAGE: en
+#+LATEX_HEADER: \usepackage[margin=1.0in]{geometry}
+#+LATEX_HEADER: \usepackage{parskip}
+#+LATEX_HEADER: \usepackage[none]{hyphenat}
+
+#+OPTIONS: H:20 num:20
+#+OPTIONS: author:nil
+
+#+HTML_HEAD: <link rel="stylesheet" href="../style.css"/>
+
+[[file:../index.html#outline-container-understanding-3d-engine][<- Back to index]]
+
+* Frustum & View Frustum Culling
+:PROPERTIES:
+:CUSTOM_ID: frustum-view-frustum-culling
+:END:
+
+#+INCLUDE: "Frustum diagram.svg" export html
+
+The *view frustum* is a truncated pyramid-shaped volume that represents
+everything the camera can see. Objects completely outside this volume are
+skipped during rendering — a powerful optimization called *frustum culling*.
+
+** The Six Frustum Planes
+:PROPERTIES:
+:CUSTOM_ID: frustum-planes
+:END:
+
+The frustum is defined by six clipping planes:
+
+| Plane | Purpose |
+|---------+--------------------------------------------|
+| Left | Left edge of viewport |
+| Right | Right edge of viewport |
+| Top | Top edge of viewport (smaller Y in Y-down) |
+| Bottom | Bottom edge of viewport (larger Y) |
+| Near | Closest visible distance from camera |
+| Far | Farthest visible distance from camera |
+
+Each plane divides 3D space into "inside" (visible) and "outside"
+(culled). An object must pass all six plane tests to be considered
+potentially visible.
+
+** Frustum Culling vs Backface Culling
+:PROPERTIES:
+:CUSTOM_ID: frustum-vs-backface-culling
+:END:
+
+These are complementary optimizations at different levels:
+
+| Optimization | Level | What it skips |
+|-----------------+--------------+----------------------------------|
+| Frustum culling | Object level | Entire composite shapes + children |
+| Backface culling | Polygon level | Individual triangles facing away |
+
+*Frustum culling* happens first during the transform phase — entire
+object trees are skipped with a single bounding box test. *Backface
+culling* happens later during rasterization — individual triangles
+are checked before being drawn.
+
+For best performance, use both: organize your scene with composite
+shapes for effective frustum culling, and enable backface culling on
+closed meshes.
+
+* How Frustum Culling Works in Aukio 3D
+:PROPERTIES:
+:CUSTOM_ID: frustum-culling-implementation
+:END:
+
+Frustum culling is applied automatically to all [[../index.org#mesh][composite shapes]]
+during Phase 1 (transform) of the [[../Rendering loop/][rendering loop]]:
+
+1. *Update frustum*: Compute 6 planes from camera FOV and viewport size
+2. *For each composite shape*:
+ - Get its [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/geometry/Box.html][Axis-Aligned Bounding Box (AABB)]]
+ - Transform all 8 corners to view space
+ - Test against frustum using [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/geometry/Frustum.html#intersectsAABB][intersectsAABB()]]
+ - If outside: skip the entire composite and all children
+ - If inside: continue transforming children
+
+(The root composite itself is never tested — it is always rendered.)
+
+** The AABB Intersection Algorithm
+:PROPERTIES:
+:CUSTOM_ID: aabb-intersection-algorithm
+:END:
+
+The intersection test uses an optimized "P-vertex" approach:
+
+#+INCLUDE: "P-vertex AABB.svg" export html
+
+For each plane, instead of testing all 8 corners of the bounding box,
+we test only the *P-vertex* — the corner most aligned with the plane
+normal. If this "best" corner is behind the plane, the entire box must
+be outside the frustum.
+
+- Plane normal points *into* the frustum (toward visible region)
+- P-vertex: select corner based on normal direction
+ - If normal.x > 0 → use maxX (rightmost corner)
+ - If normal.x < 0 → use minX (leftmost corner)
+ - Same logic for Y and Z
+- Test: =dot(normal, P-vertex) < distance= → outside
+
+This reduces from 48 tests (8 corners × 6 planes) to just 6 tests per
+object.
+
+* Performance Benefits
+:PROPERTIES:
+:CUSTOM_ID: frustum-performance
+:END:
+
+Frustum culling can dramatically improve performance for large scenes:
+
+- *High cull % (60-90%)*: Excellent — most objects skipped entirely
+- *Medium cull % (20-60%)*: Moderate benefit
+- *Low cull % (0-20%)*: Limited benefit — most objects visible
+
+A composite shape that is culled skips:
+- Transforming all its children
+- Computing bounding boxes for children
+- All polygon-level operations (backface culling, rasterization)
+
+Open Developer Tools (F12) to see real-time [[../index.org#frustum-culling-statistics][frustum culling statistics]].
+
+* Scene Design for Effective Culling
+:PROPERTIES:
+:CUSTOM_ID: frustum-scene-design
+:END:
+
+Frustum culling works best when you organize your scene into
+well-defined composite shapes:
+
+#+BEGIN_SRC java
+// Good: Each building is a separate composite
+AbstractCompositeShape cityBlock = new AbstractCompositeShape();
+for (Building building : buildings) {
+ AbstractCompositeShape buildingComposite = new AbstractCompositeShape();
+ buildingComposite.addShape(buildingWalls);
+ buildingComposite.addShape(buildingRoof);
+ buildingComposite.addShape(buildingInterior);
+ cityBlock.addShape(buildingComposite);
+}
+
+// Less effective: Everything in one giant composite
+AbstractCompositeShape allObjects = new AbstractCompositeShape();
+allObjects.addShape(building1Walls);
+allObjects.addShape(building1Roof);
+allObjects.addShape(building2Walls);
+// ... hundreds of shapes directly in root
+#+END_SRC
+
+*Best practices:*
+
+- Use composites to group objects that occupy a bounded region of space
+- Keep bounding boxes tight (don't add distant objects to the same composite)
+- Nest composites hierarchically for multi-level culling (city → block → building)
+- Call [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/AbstractShape.html#invalidateBounds()][invalidateBounds()]] after moving shapes — the bounding box is
+ recomputed lazily on next use
+
+* Technical Details
+:PROPERTIES:
+:CUSTOM_ID: frustum-technical-details
+:END:
+
+The [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/geometry/Frustum.html][Frustum]] class:
+
+- Computes planes in *view space* (camera at origin, looking along +Z)
+- FOV derived from =projectionScale = width / 3= (≈112° horizontal FOV)
+- Default clip distances: Near = 1.0, Far = 10000.0
+- Planes stored in [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/geometry/Plane.html][Hesse normal form]]: (normal vector, distance)
+
+The frustum is updated once per render pass in
+[[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/ShapeCollection.html][ShapeCollection.transformShapesBegin()]], from the camera state and
+the stereo viewport width — in stereo mode each eye gets its own
+frustum, so the update runs twice per frame.
--- /dev/null
+<svg viewBox="0 0 640 480" width="640" height="480" xmlns="http://www.w3.org/2000/svg">
+ <defs>
+ <filter id="glow">
+ <feGaussianBlur stdDeviation="2" result="blur"/>
+ <feMerge>
+ <feMergeNode in="blur"/>
+ <feMergeNode in="SourceGraphic"/>
+ </feMerge>
+ </filter>
+ <marker id="arrowGold" markerWidth="8" markerHeight="6" refX="7" refY="3" orient="auto">
+ <polygon points="0,0 8,3 0,6" fill="#b09020"/>
+ </marker>
+ <marker id="arrowCyan" markerWidth="8" markerHeight="6" refX="7" refY="3" orient="auto">
+ <polygon points="0,0 8,3 0,6" fill="#40b0d0"/>
+ </marker>
+ <marker id="arrowGreen" markerWidth="8" markerHeight="6" refX="7" refY="3" orient="auto">
+ <polygon points="0,0 8,3 0,6" fill="#39FF14"/>
+ </marker>
+ </defs>
+ <rect width="640" height="480" fill="#061018"/>
+
+ <!-- floor -->
+ <line x1="50" y1="390" x2="600" y2="390" stroke="#30a050" stroke-width="3"/>
+ <text x="60" y="410" fill="#30a050" font-size="11" font-family="monospace">surface</text>
+
+ <!-- wall on the right -->
+ <line x1="480" y1="170" x2="480" y2="390" stroke="#30a050" stroke-width="3"/>
+
+ <!-- sample point P + normal -->
+ <circle cx="230" cy="390" r="6" fill="#c05088" filter="url(#glow)"/>
+ <text x="218" y="414" fill="#c05088" font-size="13" font-family="monospace" text-anchor="middle">P</text>
+ <line x1="230" y1="384" x2="230" y2="300" stroke="#b09020" stroke-width="2" marker-end="url(#arrowGold)"/>
+ <text x="240" y="330" fill="#b09020" font-size="11" font-family="monospace">normal</text>
+
+ <!-- cosine hemisphere dome -->
+ <path d="M 140 390 A 90 90 0 0 1 320 390" fill="none" stroke="#40b0d0" stroke-width="1.5" stroke-dasharray="6 3"/>
+ <text x="150" y="292" fill="#40b0d0" font-size="10" font-family="monospace">cosine-weighted</text>
+ <text x="150" y="306" fill="#40b0d0" font-size="10" font-family="monospace">hemisphere</text>
+
+ <!-- a few faint sample rays -->
+ <line x1="230" y1="384" x2="160" y2="310" stroke="#40b0d0" stroke-width="1" stroke-dasharray="3 2"/>
+ <line x1="230" y1="384" x2="300" y2="306" stroke="#40b0d0" stroke-width="1" stroke-dasharray="3 2"/>
+
+ <!-- THE bounce ray: P to Q on the wall -->
+ <line x1="230" y1="384" x2="472" y2="288" stroke="#40b0d0" stroke-width="2.5" marker-end="url(#arrowCyan)" filter="url(#glow)"/>
+ <circle cx="476" cy="285" r="6" fill="#40b0d0" filter="url(#glow)"/>
+ <text x="492" y="280" fill="#40b0d0" font-size="13" font-family="monospace">Q</text>
+
+ <!-- lamp -->
+ <circle cx="540" cy="70" r="14" fill="rgba(255,102,0,0.25)" stroke="#FF6600" stroke-width="2" filter="url(#glow)"/>
+ <circle cx="540" cy="70" r="5" fill="#FF6600"/>
+ <text x="540" y="104" fill="#FF8833" font-size="11" font-family="monospace" text-anchor="middle">light</text>
+
+ <!-- shadow ray P -> light (visible) -->
+ <line x1="236" y1="384" x2="528" y2="76" stroke="#39FF14" stroke-width="1.5" stroke-dasharray="8 4" marker-end="url(#arrowGreen)"/>
+ <text x="330" y="230" fill="#39FF14" font-size="10" font-family="monospace" transform="rotate(-52 330 230)">shadow ray: clear</text>
+
+ <!-- occluded shadow ray from a second point -->
+ <circle cx="400" cy="390" r="4" fill="rgba(192,80,136,0.6)"/>
+ <line x1="404" y1="384" x2="452" y2="240" stroke="#FF4444" stroke-width="1.5" stroke-dasharray="4 3"/>
+ <rect x="438" y="196" width="34" height="44" fill="rgba(255,68,68,0.15)" stroke="#FF4444" stroke-width="1.5"/>
+ <text x="455" y="188" fill="#FF4444" font-size="10" font-family="monospace" text-anchor="middle">occluder</text>
+ <text x="438" y="330" fill="#FF4444" font-size="10" font-family="monospace" transform="rotate(-62 438 330)">blocked</text>
+
+ <!-- what happens at Q -->
+ <rect x="360" y="120" width="260" height="58" rx="6" fill="rgba(32,112,192,0.1)" stroke="#2070c0" stroke-width="1.5"/>
+ <text x="372" y="142" fill="#2070c0" font-size="11" font-family="monospace">at Q: direct light (cached shadow bits)</text>
+ <text x="372" y="160" fill="#2070c0" font-size="11" font-family="monospace"> + Q's current indirect estimate</text>
+
+ <!-- P's update -->
+ <rect x="60" y="60" width="280" height="44" rx="6" fill="rgba(48,160,80,0.1)" stroke="#30a050" stroke-width="1.5"/>
+ <text x="72" y="78" fill="#39FF14" font-size="11" font-family="monospace">P's target = (albedo / π) x (direct + indirect)</text>
+ <text x="72" y="94" fill="#30a050" font-size="10" font-family="monospace">blended in with an exponential moving average</text>
+
+ <text x="320" y="462" fill="#aaa" font-size="10" font-family="monospace" text-anchor="middle">one sample per texel per visit: one shadow ray + one bounce ray — bounce light ripples deeper every sweep</text>
+</svg>
--- /dev/null
+<svg viewBox="0 0 620 170" width="620" height="170" xmlns="http://www.w3.org/2000/svg">
+ <defs>
+ <filter id="glow">
+ <feGaussianBlur stdDeviation="1.5" result="blur"/>
+ <feMerge>
+ <feMergeNode in="blur"/>
+ <feMergeNode in="SourceGraphic"/>
+ </feMerge>
+ </filter>
+ <marker id="arrowhead" markerWidth="8" markerHeight="6" refX="7" refY="3" orient="auto">
+ <polygon points="0,0 8,3 0,6" fill="#40b0d0"/>
+ </marker>
+ </defs>
+ <rect width="620" height="170" fill="#061018"/>
+
+ <!-- pipeline boxes -->
+ <rect x="10" y="45" width="104" height="64" rx="3" fill="rgba(80,96,192,0.15)" stroke="#5060c0" stroke-width="1.5"/>
+ <text x="62" y="66" fill="#5060c0" font-size="10" font-family="monospace" text-anchor="middle" font-weight="bold">scene snapshot</text>
+ <text x="62" y="80" fill="#aaa" font-size="9" font-family="monospace" text-anchor="middle">triangles + lights</text>
+ <text x="62" y="92" fill="#aaa" font-size="9" font-family="monospace" text-anchor="middle">+ BVH</text>
+
+ <rect x="136" y="45" width="104" height="64" rx="3" fill="rgba(255,102,0,0.15)" stroke="#FF6600" stroke-width="1.5"/>
+ <text x="188" y="66" fill="#FF8833" font-size="10" font-family="monospace" text-anchor="middle" font-weight="bold">GI workers</text>
+ <text x="188" y="80" fill="#aaa" font-size="9" font-family="monospace" text-anchor="middle">Monte Carlo</text>
+ <text x="188" y="92" fill="#aaa" font-size="9" font-family="monospace" text-anchor="middle">sweeps</text>
+
+ <rect x="262" y="45" width="104" height="64" rx="3" fill="rgba(48,160,80,0.15)" stroke="#30a050" stroke-width="1.5"/>
+ <text x="314" y="66" fill="#39FF14" font-size="10" font-family="monospace" text-anchor="middle" font-weight="bold">lightmaps</text>
+ <text x="314" y="80" fill="#aaa" font-size="9" font-family="monospace" text-anchor="middle">per-texel indirect</text>
+ <text x="314" y="92" fill="#aaa" font-size="9" font-family="monospace" text-anchor="middle">+ shadow bits</text>
+
+ <rect x="388" y="45" width="104" height="64" rx="3" fill="rgba(192,80,136,0.15)" stroke="#c05088" stroke-width="1.5"/>
+ <text x="440" y="60" fill="#c05088" font-size="10" font-family="monospace" text-anchor="middle" font-weight="bold">composite</text>
+ <text x="440" y="74" fill="#aaa" font-size="9" font-family="monospace" text-anchor="middle">baseColor x light</text>
+ <text x="440" y="86" fill="#aaa" font-size="9" font-family="monospace" text-anchor="middle">double-buffered</text>
+ <text x="440" y="98" fill="#aaa" font-size="9" font-family="monospace" text-anchor="middle">swap</text>
+
+ <rect x="514" y="45" width="96" height="64" rx="3" fill="rgba(64,176,208,0.15)" stroke="#40b0d0" stroke-width="1.5"/>
+ <text x="562" y="66" fill="#40b0d0" font-size="10" font-family="monospace" text-anchor="middle" font-weight="bold">painter</text>
+ <text x="562" y="80" fill="#aaa" font-size="9" font-family="monospace" text-anchor="middle">plain texture</text>
+ <text x="562" y="92" fill="#aaa" font-size="9" font-family="monospace" text-anchor="middle">lookup</text>
+
+ <!-- arrows -->
+ <line x1="114" y1="77" x2="134" y2="77" stroke="#40b0d0" stroke-width="1.5" marker-end="url(#arrowhead)"/>
+ <line x1="240" y1="77" x2="260" y2="77" stroke="#40b0d0" stroke-width="1.5" marker-end="url(#arrowhead)"/>
+ <line x1="366" y1="77" x2="386" y2="77" stroke="#40b0d0" stroke-width="1.5" marker-end="url(#arrowhead)"/>
+ <line x1="492" y1="77" x2="512" y2="77" stroke="#40b0d0" stroke-width="1.5" marker-end="url(#arrowhead)"/>
+
+ <!-- feedback arrow: lightmaps feed the next sweep's bounce targets -->
+ <path d="M 314 109 L 314 135 L 188 135 L 188 111" fill="none" stroke="#30a050" stroke-width="1.2" stroke-dasharray="4 3" marker-end="url(#arrowhead)"/>
+ <text x="251" y="147" fill="#30a050" font-size="9" font-family="monospace" text-anchor="middle">bounce reads last sweep's estimate</text>
+
+ <text x="562" y="135" fill="#666" font-size="9" font-family="monospace" text-anchor="middle">zero ray casting</text>
+ <text x="562" y="147" fill="#666" font-size="9" font-family="monospace" text-anchor="middle">on render threads</text>
+</svg>
--- /dev/null
+<svg viewBox="0 0 640 480" width="640" height="480" xmlns="http://www.w3.org/2000/svg">
+ <defs>
+ <filter id="glow">
+ <feGaussianBlur stdDeviation="1.5" result="blur"/>
+ <feMerge>
+ <feMergeNode in="blur"/>
+ <feMergeNode in="SourceGraphic"/>
+ </feMerge>
+ </filter>
+ <marker id="arrowhead2" markerWidth="8" markerHeight="6" refX="7" refY="3" orient="auto">
+ <polygon points="0,0 8,3 0,6" fill="#b09020"/>
+ </marker>
+ </defs>
+ <rect width="640" height="480" fill="#061018"/>
+
+ <!-- bounding square: the full texture; valid region is the lower-left half (u+v <= 1) -->
+ <rect x="140" y="80" width="320" height="320" fill="rgba(255,68,68,0.06)" stroke="#FF4444" stroke-width="1.5" stroke-dasharray="4 3"/>
+ <text x="372" y="110" fill="#FF4444" font-size="10" font-family="monospace" text-anchor="middle">invalid half (u+v > 1)</text>
+ <text x="372" y="126" fill="#FF4444" font-size="9" font-family="monospace" text-anchor="middle">filled from neighbors so sampling</text>
+ <text x="372" y="138" fill="#FF4444" font-size="9" font-family="monospace" text-anchor="middle">near the hypotenuse stays clean</text>
+
+ <!-- the triangle (valid region) -->
+ <polygon points="140,400 460,400 140,80" fill="rgba(48,160,80,0.12)" stroke="#39FF14" stroke-width="2" filter="url(#glow)"/>
+
+ <!-- texel grid inside the triangle (8x8) -->
+ <line x1="180" y1="360" x2="180" y2="400" stroke="#1a3a4a" stroke-width="1"/>
+ <line x1="220" y1="320" x2="220" y2="400" stroke="#1a3a4a" stroke-width="1"/>
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+ <line x1="140" y1="120" x2="180" y2="120" stroke="#1a3a4a" stroke-width="1"/>
+
+ <!-- texel center dots -->
+ <circle cx="160" cy="380" r="2" fill="#c05088"/>
+ <circle cx="200" cy="380" r="2" fill="#c05088"/>
+ <circle cx="240" cy="380" r="2" fill="#c05088"/>
+ <circle cx="160" cy="340" r="2" fill="#c05088"/>
+ <circle cx="200" cy="340" r="2" fill="#c05088"/>
+ <circle cx="160" cy="300" r="2" fill="#c05088"/>
+
+ <!-- one texel highlighted with its world position -->
+ <rect x="200" y="280" width="40" height="40" fill="rgba(255,136,51,0.2)" stroke="#FF8833" stroke-width="1.5"/>
+ <circle cx="220" cy="300" r="3.5" fill="#FF6600" filter="url(#glow)"/>
+ <text x="190" y="348" fill="#FF8833" font-size="10" font-family="monospace">one texel = one surface</text>
+ <text x="190" y="362" fill="#FF8833" font-size="10" font-family="monospace">patch, sampled at center</text>
+
+ <!-- vertices -->
+ <circle cx="140" cy="400" r="6" fill="#c05088"/>
+ <text x="128" y="420" fill="#c05088" font-size="12" font-family="monospace" text-anchor="middle">a (u=0, v=0)</text>
+ <circle cx="460" cy="400" r="6" fill="#c05088"/>
+ <text x="460" y="420" fill="#c05088" font-size="12" font-family="monospace" text-anchor="middle">b (u=1, v=0)</text>
+ <circle cx="140" cy="80" r="6" fill="#c05088"/>
+ <text x="128" y="70" fill="#c05088" font-size="12" font-family="monospace" text-anchor="middle">c (u=0, v=1)</text>
+
+ <!-- edge vectors -->
+ <line x1="140" y1="396" x2="300" y2="396" stroke="#b09020" stroke-width="1.5" marker-end="url(#arrowhead2)"/>
+ <text x="225" y="440" fill="#b09020" font-size="11" font-family="monospace" text-anchor="middle">e1 = b − a</text>
+ <line x1="144" y1="400" x2="144" y2="240" stroke="#b09020" stroke-width="1.5" marker-end="url(#arrowhead2)"/>
+ <text x="100" y="330" fill="#b09020" font-size="11" font-family="monospace" text-anchor="middle">e2 = c − a</text>
+
+ <!-- formula box -->
+ <rect x="390" y="180" width="230" height="64" rx="6" fill="rgba(32,112,192,0.1)" stroke="#2070c0" stroke-width="1.5"/>
+ <text x="402" y="204" fill="#2070c0" font-size="12" font-family="monospace">world(u,v) = a + e1·u + e2·v</text>
+ <text x="402" y="226" fill="#2070c0" font-size="10" font-family="monospace">texels = edge / unitsPerTexel</text>
+
+ <text x="320" y="462" fill="#aaa" font-size="10" font-family="monospace" text-anchor="middle">every texel owns a fixed patch of the triangle — shadows and gradients live INSIDE the surface</text>
+</svg>
--- /dev/null
+#+SETUPFILE: ~/.emacs.d/org-styles/html/darksun.theme
+#+TITLE: Global Illumination - Aukio 3D
+#+LANGUAGE: en
+#+LATEX_HEADER: \usepackage[margin=1.0in]{geometry}
+#+LATEX_HEADER: \usepackage{parskip}
+#+LATEX_HEADER: \usepackage[none]{hyphenat}
+
+#+OPTIONS: H:20 num:20
+#+OPTIONS: author:nil
+
+#+HTML_HEAD: <link rel="stylesheet" href="../style.css"/>
+
+[[file:../index.html#outline-container-understanding-3d-engine][<- Back to index]]
+
+* What global illumination adds
+:PROPERTIES:
+:CUSTOM_ID: what-gi-adds
+:END:
+
+Plain per-polygon shading lights every polygon with one flat color:
+no shadows, and surfaces that receive no direct light stay uniformly
+dark. A room corner reads as a flat silhouette instead of a corner.
+
+#+attr_html: :class responsive-img
+#+attr_latex: :width 640px
+[[file:gi-flat.png]]
+
+*Aukio 3D* can optionally compute *global illumination* progressively
+on background CPU threads: shadows appear, light pools under lamps
+with smooth falloff, and colored light *bleeds* — a red sofa tints the
+floor next to it red. All of it converges gradually over the first
+seconds of a scene, then idles.
+
+Same camera, same house: flat shading (top) versus converged GI
+(below). Note the soft shadow of the partition wall, the lamp glow on
+the ceiling, and the subtle color variation across the floor.
+
+#+attr_html: :class responsive-img
+#+attr_latex: :width 640px
+[[file:gi-converged.png]]
+
+* The big idea: GI off the render path
+:PROPERTIES:
+:CUSTOM_ID: off-the-render-path
+:END:
+
+Ray tracing is far too slow to run per frame in a software renderer,
+so it doesn't: *the render loop never traces a single ray.* Painting a
+lightmapped triangle is an ordinary texture lookup, exactly as fast as
+any textured polygon.
+
+All the expensive work happens on dedicated low-priority worker threads
+that continuously refine per-surface lighting values. Whenever the
+values have improved enough, the workers regenerate each triangle's
+*composite texture* (baseColor x total lighting) into a back buffer
+and swap it in atomically — painters never see a half-updated texture.
+
+#+INCLUDE: "GI pipeline.svg" export html
+
+Because painters only read finished textures, frame rate is completely
+decoupled from GI quality: you can crank lightmap resolution up and the
+only cost is CPU time on the worker threads, not frame time.
+
+* Lightmaps: a texture per triangle
+:PROPERTIES:
+:CUSTOM_ID: lightmaps
+:END:
+
+Flat shading can only color a polygon uniformly — shadows and gradients
+need resolution *inside* the polygon. Every lightmapped triangle
+therefore owns a small generated texture, its *lightmap*, whose texels
+map onto the triangle surface by an affine rule:
+
+#+INCLUDE: "Lightmap mapping.svg" export html
+
+The triangle's UVs are pinned to (0,0), (1,0), (0,1), so the valid
+texel region is the half where u+v <= 1; the other half of the square
+texture is flood-filled from valid neighbors so that nearest sampling
+near the hypotenuse never picks up garbage.
+
+Each texel stores two things, both written only by GI threads:
+
+- *Indirect irradiance* (RGB floats) — the accumulated bounced light.
+- *Per-light visibility bits* — whether the last shadow ray from this
+ texel reached each lamp (cached so later queries cost nothing).
+
+Resolution is set in world units per texel
+(=LightmappedCompositeShape.setLightmapUnitsPerTexel()=, default 12): a 100-unit
+wall cell gets an 8x8 lightmap. Halving the units quadruples the
+tracing work.
+
+*What you trace is what you see:* the composite texture the painter
+samples is the lightmap itself, at native texel resolution — there is
+no upscaling step. Shadow-edge smoothness comes from tracing at finer
+resolution, never from interpolation. (An earlier bilinear-upscaling
+pass produced visibly artificial results and was removed; finer texels
+cost more CPU on the GI threads but look right.)
+
+* One sample: a shadow ray and a bounce ray
+:PROPERTIES:
+:CUSTOM_ID: one-sample
+:END:
+
+The work list is flat: one item per lightmap texel (and one per plain
+polygon, see below). Worker threads walk it round-robin, and every
+visit to a texel casts exactly two rays from the texel's world
+position, nudged slightly off the surface along the normal:
+
+1. *Shadow ray* toward a lamp. Answers visible/occluded, cached in the
+ texel's visibility bits. On a texel's *first* visit all lamps are
+ tested at once, so direct light and hard shadows appear after a
+ single sweep instead of trickling in lamp by lamp; later visits
+ re-test one lamp at a time, round-robin.
+2. *Bounce ray* in a random cosine-weighted direction around the
+ normal. Wherever it lands (point Q), the sample reads Q's *direct*
+ lighting — using Q's cached shadow bits, no new shadow rays — plus
+ Q's *current indirect estimate*, and blends the sum into the texel's
+ own indirect value.
+
+#+INCLUDE: "Bounce estimator.svg" export html
+
+Reading Q's current indirect estimate instead of recursing is what
+makes bounce light propagate: sweep 1 learns "Q is directly lit",
+sweep 2 learns "P sees a lit Q", sweep 3 learns "R sees a lit P"...
+Light ripples one surface deeper with every sweep, with no recursion
+limit and no exponential ray explosion. The =1/pi= diffuse gain keeps
+the feedback loop from diverging: without it the indirect term
+amplifies itself and the scene saturates to white.
+
+* Progressive convergence
+:PROPERTIES:
+:CUSTOM_ID: convergence
+:END:
+
+Monte Carlo samples are noisy, so blending happens at *two nested
+levels*, both exponential moving averages:
+
+1. *Inner, per sample*: each texel blends every new bounce-ray result
+ into its indirect estimate with a constant weight (=alpha = 0.15=,
+ mode =fixed=). Every ray hit stays equally intensive forever — an
+ unlit area fades to darkness at the same rate a lit area brightens.
+ (The old =adaptive= mode, which decays alpha with sample count, is
+ still available; see the knobs below.)
+2. *Outer, per composite update*: the value that reaches the screen is
+ a second EMA over the COMPLETE sum =ambient + direct + indirect=.
+ The texture can only move =e3d.gi.compositeAlpha= (default 0.2) of
+ the remaining distance per 500 ms update — so direct light, shadows
+ and bounce light all glide in together over a few seconds, and no
+ single-frame jump is possible by construction.
+
+The world starts at a *uniform medium irradiance*
+(=e3d.gi.initialIrradiance=, default 128): the scene is visible from
+the very first frame, then lit areas brighten and unlit areas sink to
+darkness as the workers sweep — lights and shadows gradually become
+distinguished instead of the old pitch-black start with a sudden flash
+once the first sweep landed:
+
+#+attr_html: :class responsive-img
+#+attr_latex: :width 640px
+[[file:gi-start.png]]
+
+Consequences of the design:
+
+- *Hysteresis is free*: when a lamp moves or geometry changes, old
+ light fades out gradually instead of popping — the same pair of EMAs
+ that accumulates light also drains it.
+- *Convergence detection*: per-sample deltas are pure noise (and with a
+ constant alpha they never settle), so the system watches the average
+ per-texel movement of the on-screen estimate; after five composite
+ updates below =e3d.gi.calmThreshold= (default 1.0 light unit) the
+ workers drop to a low duty cycle (~50% of sweep time, capped) instead
+ of burning CPU. Any scene or light change rebuilds the snapshot and
+ restarts full-speed tracing.
+- *Despeckle*: at composite time the indirect channel is blended 50/50
+ with the mean of its valid 4-neighbors, killing single-texel Monte
+ Carlo spikes without blurring real gradients.
+- *Composite cadence*: textures regenerate at most every 500 ms — one
+ atomic swap per triangle, invisible to painters.
+
+* Plain polygons get GI too
+:PROPERTIES:
+:CUSTOM_ID: plain-polygons
+:END:
+
+Surfaces that are not lightmapped (ordinary =SolidPolygon= with shading
+enabled) still benefit, at per-polygon resolution, through the
+[[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/lighting/GiLightProvider.html][GiLightProvider]]
+interface that =GlobalIllumination= installs into the
+[[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/lighting/LightingManager.html][LightingManager]]:
+
+- =isLightVisible(polygon, light)= answers from cached shadow bits —
+ direct-light shadows fade in on flat-shaded geometry.
+- =addIndirectLight(polygon, baseColor, result)= adds the polygon's
+ bounced-light estimate into the flat-shaded color.
+
+Both are called from parallel render-pool threads, so they only read
+volatile caches — never trace.
+
+* Enabling GI
+:PROPERTIES:
+:CUSTOM_ID: enabling
+:END:
+
+#+BEGIN_SRC java
+// Per-texel lightmaps on composite geometry (the House demo setup):
+LightmappedCompositeShape house = new LightmappedCompositeShape();
+house.setLightmappingEnabled(true);
+house.setLightmapUnitsPerTexel(3.0); // fine texels: quality from traced rays
+
+// Start the workers (2 threads by default; more converge faster):
+viewPanel.enableGlobalIllumination(4);
+#+END_SRC
+
+Tuning knobs (system properties):
+
+| Property | Default | Effect |
+|---------------------------+---------+-----------------------------------------|
+| =e3d.gi.alphaMode= | fixed | =adaptive= decays the inner EMA alpha with sample count |
+| =e3d.gi.alphaFloor= | 0.08 | adaptive-mode floor; higher adapts faster but noisier |
+| =e3d.gi.compositeAlpha= | 0.2 | outer EMA: fade speed of the on-screen estimate per 500 ms update |
+| =e3d.gi.initialIrradiance=| 128 | uniform medium start (0..255 light units) |
+| =e3d.gi.calmThreshold= | 1.0 | convergence: avg estimate movement (light units) |
+| =e3d.gi.despeckle= | true | neighbor-smoothing of indirect at composite time |
+| =e3d.gi.debug= | false | sweep statistics to stdout |
+| =e3d.gi.dumpLightmaps= | (unset) | dump composite lightmaps as PNGs to the given dir |
+
+* Limitations
+:PROPERTIES:
+:CUSTOM_ID: limitations
+:END:
+
+- *Diffuse light only* — no specular bounce, no caustics.
+- Polygon vertices are traced in composite-local space; scenes that put
+ non-identity transforms on composites are traced incorrectly.
+- The bounce estimate is one ray deep per sample — correctness comes
+ from sweep-over-sweep propagation, so deeply indirect corners take
+ several sweeps to brighten.
+
+* Related Classes
+:PROPERTIES:
+:CUSTOM_ID: related-classes
+:END:
+
+| Class | Purpose |
+|----------------------+---------------------------------------------------------------|
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/gi/GlobalIllumination.html][GlobalIllumination]] | Progressive tracer: sweeps, EMA convergence, composite swaps |
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/gi/Lightmap.html][Lightmap]] | Per-triangle texel state + double-buffered composite textures |
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/gi/LightmappedTriangle.html][LightmappedTriangle]] | Textured triangle whose texture is the GI composite |
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/gi/TriangleBvh.html][TriangleBvh]] | BVH over world triangles: nearest-hit and any-hit ray queries (Möller–Trumbore) |
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/lighting/GiLightProvider.html][GiLightProvider]] | Cache-read interface feeding the flat-shading path |
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/composite/LightmappedCompositeShape.html][LightmappedCompositeShape]] | Wraps polygons into lightmapped triangles |
--- /dev/null
+<svg viewBox="0 0 640 480" width="640" height="480" xmlns="http://www.w3.org/2000/svg">
+ <rect width="640" height="480" fill="#061018"/>
+ <ellipse cx="320" cy="240" rx="180" ry="180" fill="none" stroke="rgba(80,96,192,0.1)" stroke-width="1"/>
+ <ellipse cx="320" cy="240" rx="180" ry="40" fill="none" stroke="rgba(80,96,192,0.25)" stroke-width="1.6"/>
+ <ellipse cx="320" cy="180" rx="150" ry="32" fill="none" stroke="rgba(80,96,192,0.2)" stroke-width="1.2"/>
+ <ellipse cx="320" cy="300" rx="150" ry="32" fill="none" stroke="rgba(80,96,192,0.2)" stroke-width="1.2"/>
+ <ellipse cx="320" cy="120" rx="90" ry="20" fill="none" stroke="rgba(80,96,192,0.15)" stroke-width="1"/>
+ <ellipse cx="320" cy="360" rx="90" ry="20" fill="none" stroke="rgba(80,96,192,0.15)" stroke-width="1"/>
+ <ellipse cx="320" cy="240" rx="40" ry="180" fill="none" stroke="rgba(80,96,192,0.2)" stroke-width="1.2"/>
+ <ellipse cx="320" cy="240" rx="110" ry="180" fill="none" stroke="rgba(80,96,192,0.15)" stroke-width="1"/>
+ <polygon points="320,60 370,116 280,110" fill="rgba(80,96,192,0.15)" stroke="#5060c0" stroke-width="2"/>
+ <polygon points="370,116 410,176 320,164" fill="rgba(80,96,192,0.1)" stroke="#5060c0" stroke-width="1.6"/>
+ <polygon points="320,164 370,116 280,110" fill="rgba(80,96,192,0.07)" stroke="rgba(80,96,192,0.5)" stroke-width="1.2"/>
+ <circle cx="320" cy="60" r="5" fill="#5060c0"/>
+ <circle cx="370" cy="116" r="5" fill="#5060c0"/>
+ <circle cx="280" cy="110" r="5" fill="#5060c0"/>
+ <circle cx="410" cy="176" r="5" fill="#5060c0"/>
+ <circle cx="320" cy="164" r="5" fill="#5060c0"/>
+ <text x="436" y="140" fill="#5060c0" font-size="20" font-weight="600" font-family="monospace">triangulated</text>
+ <text x="436" y="164" fill="#5060c0" font-size="20" font-weight="600" font-family="monospace">section</text>
+ <line x1="412" y1="150" x2="428" y2="150" stroke="#5060c0" stroke-width="1.6"/>
+</svg>
--- /dev/null
+<svg viewBox="0 0 640 480" width="640" height="480" xmlns="http://www.w3.org/2000/svg">
+ <defs>
+ <filter id="glow">
+ <feGaussianBlur stdDeviation="2" result="blur"/>
+ <feMerge>
+ <feMergeNode in="blur"/>
+ <feMergeNode in="SourceGraphic"/>
+ </feMerge>
+ </filter>
+ </defs>
+ <rect width="640" height="480" fill="#061018"/>
+
+ <!-- grid -->
+ <line x1="40" y1="120" x2="620" y2="120" stroke="#1a3a4a" stroke-width="1"/>
+ <line x1="40" y1="200" x2="620" y2="200" stroke="#1a3a4a" stroke-width="1"/>
+ <line x1="40" y1="280" x2="620" y2="280" stroke="#1a3a4a" stroke-width="1"/>
+ <line x1="40" y1="360" x2="620" y2="360" stroke="#1a3a4a" stroke-width="1"/>
+ <line x1="160" y1="60" x2="160" y2="400" stroke="#1a3a4a" stroke-width="1"/>
+ <line x1="300" y1="60" x2="300" y2="400" stroke="#1a3a4a" stroke-width="1"/>
+ <line x1="440" y1="60" x2="440" y2="400" stroke="#1a3a4a" stroke-width="1"/>
+
+ <!-- half-space labels -->
+ <text x="170" y="84" fill="#FF4444" font-size="12" font-family="monospace" text-anchor="middle">behind (z ≤ near)</text>
+ <text x="460" y="84" fill="#30a050" font-size="12" font-family="monospace" text-anchor="middle">in front (z > near)</text>
+
+ <!-- near plane -->
+ <line x1="300" y1="95" x2="300" y2="400" stroke="#40b0d0" stroke-width="2" stroke-dasharray="6 3"/>
+ <text x="310" y="110" fill="#40b0d0" font-size="12" font-family="monospace" text-anchor="start" filter="url(#glow)">near plane</text>
+
+ <!-- discarded part of the triangle -->
+ <polygon points="120,260 300,200 300,320" fill="rgba(255,68,68,0.08)" stroke="#FF4444" stroke-width="1.5" stroke-dasharray="4 3"/>
+
+ <!-- kept fragment: the clipped quad -->
+ <polygon points="480,140 480,380 300,320 300,200" fill="rgba(48,160,80,0.12)" stroke="#39FF14" stroke-width="2" filter="url(#glow)"/>
+
+ <!-- original edges continuing behind the plane (ghost) -->
+ <line x1="300" y1="200" x2="120" y2="260" stroke="#c05088" stroke-width="1.5" stroke-dasharray="3 2"/>
+ <line x1="300" y1="320" x2="120" y2="260" stroke="#c05088" stroke-width="1.5" stroke-dasharray="3 2"/>
+
+ <!-- vertices -->
+ <circle cx="480" cy="140" r="6" fill="#c05088"/>
+ <text x="496" y="144" fill="#c05088" font-size="13" font-family="monospace">v0</text>
+ <circle cx="480" cy="380" r="6" fill="#c05088"/>
+ <text x="496" y="384" fill="#c05088" font-size="13" font-family="monospace">v1</text>
+ <circle cx="120" cy="260" r="6" fill="rgba(192,80,136,0.45)"/>
+ <text x="104" y="246" fill="#c05088" font-size="13" font-family="monospace" opacity="0.7">v2</text>
+
+ <!-- intersection vertices -->
+ <circle cx="300" cy="200" r="6" fill="#39FF14" filter="url(#glow)"/>
+ <text x="284" y="190" fill="#39FF14" font-size="13" font-family="monospace" text-anchor="end">p′</text>
+ <circle cx="300" cy="320" r="6" fill="#39FF14" filter="url(#glow)"/>
+ <text x="314" y="340" fill="#39FF14" font-size="13" font-family="monospace" text-anchor="start">p″</text>
+
+ <!-- t parameter marker on edge v0-v2, with leader line -->
+ <text x="210" y="140" fill="#FF8833" font-size="11" font-family="monospace" text-anchor="middle">t = 0.5 along v0 → v2</text>
+ <line x1="280" y1="146" x2="380" y2="166" stroke="#FF8833" stroke-width="1" stroke-dasharray="3 2"/>
+
+ <!-- formula box -->
+ <rect x="50" y="320" width="210" height="86" rx="6" fill="rgba(32,112,192,0.1)" stroke="#2070c0" stroke-width="1.5"/>
+ <text x="62" y="342" fill="#2070c0" font-size="12" font-family="monospace">t = (near − z1) / (z2 − z1)</text>
+ <text x="62" y="362" fill="#2070c0" font-size="12" font-family="monospace">p = p1 + t·(p2 − p1)</text>
+ <text x="62" y="382" fill="#2070c0" font-size="12" font-family="monospace">uv = uv1 + t·(uv2 − uv1)</text>
+
+ <text x="320" y="438" fill="#aaa" font-size="10" font-family="monospace" text-anchor="middle">every edge crossing the plane spawns an interpolated vertex;</text>
+ <text x="320" y="454" fill="#aaa" font-size="10" font-family="monospace" text-anchor="middle">in-front vertices pass through unchanged</text>
+</svg>
--- /dev/null
+<svg viewBox="0 0 620 240" width="620" height="240" xmlns="http://www.w3.org/2000/svg">
+ <defs>
+ <filter id="glow">
+ <feGaussianBlur stdDeviation="1.5" result="blur"/>
+ <feMerge>
+ <feMergeNode in="blur"/>
+ <feMergeNode in="SourceGraphic"/>
+ </feMerge>
+ </filter>
+ </defs>
+ <rect width="620" height="240" fill="#061018"/>
+
+ <!-- clipped quad -->
+ <polygon points="120,50 330,50 400,180 170,180" fill="rgba(48,160,80,0.12)" stroke="#39FF14" stroke-width="2"/>
+
+ <!-- fan split from v0 -->
+ <line x1="120" y1="50" x2="400" y2="180" stroke="#FF6600" stroke-width="1.5" stroke-dasharray="6 3"/>
+
+ <!-- vertices -->
+ <circle cx="120" cy="50" r="5" fill="#c05088"/>
+ <text x="108" y="42" fill="#c05088" font-size="12" font-family="monospace" text-anchor="middle">v0</text>
+ <circle cx="330" cy="50" r="5" fill="#c05088"/>
+ <text x="330" y="42" fill="#c05088" font-size="12" font-family="monospace" text-anchor="middle">v1</text>
+ <circle cx="400" cy="180" r="5" fill="#39FF14" filter="url(#glow)"/>
+ <text x="408" y="198" fill="#39FF14" font-size="12" font-family="monospace">p″</text>
+ <circle cx="170" cy="180" r="5" fill="#39FF14" filter="url(#glow)"/>
+ <text x="162" y="198" fill="#39FF14" font-size="12" font-family="monospace" text-anchor="end">p′</text>
+
+ <!-- triangle labels -->
+ <text x="245" y="100" fill="#FF8833" font-size="12" font-family="monospace" text-anchor="middle">T1 = (v0, v1, p″)</text>
+ <text x="225" y="152" fill="#FF8833" font-size="12" font-family="monospace" text-anchor="middle">T2 = (v0, p″, p′)</text>
+
+ <!-- caption -->
+ <text x="460" y="60" fill="#aaa" font-size="11" font-family="monospace">a triangle cut once</text>
+ <text x="460" y="78" fill="#aaa" font-size="11" font-family="monospace">becomes a quad;</text>
+ <text x="460" y="96" fill="#aaa" font-size="11" font-family="monospace">the rasterizer paints it</text>
+ <text x="460" y="114" fill="#aaa" font-size="11" font-family="monospace">as a 2-triangle fan</text>
+ <text x="460" y="132" fill="#aaa" font-size="11" font-family="monospace">sharing v0</text>
+</svg>
--- /dev/null
+<svg viewBox="0 0 620 300" width="620" height="300" xmlns="http://www.w3.org/2000/svg">
+ <defs>
+ <filter id="glow">
+ <feGaussianBlur stdDeviation="2" result="blur"/>
+ <feMerge>
+ <feMergeNode in="blur"/>
+ <feMergeNode in="SourceGraphic"/>
+ </feMerge>
+ </filter>
+ </defs>
+ <rect width="620" height="300" fill="#061018"/>
+
+ <!-- grid -->
+ <line x1="40" y1="80" x2="600" y2="80" stroke="#1a3a4a" stroke-width="1"/>
+ <line x1="40" y1="140" x2="600" y2="140" stroke="#1a3a4a" stroke-width="1"/>
+ <line x1="40" y1="200" x2="600" y2="200" stroke="#1a3a4a" stroke-width="1"/>
+ <line x1="40" y1="260" x2="600" y2="260" stroke="#1a3a4a" stroke-width="1"/>
+
+ <!-- axes -->
+ <line x1="40" y1="270" x2="600" y2="270" stroke="#2070c0" stroke-width="2"/>
+ <text x="592" y="290" fill="#2070c0" font-size="12" font-family="monospace" text-anchor="end">z (depth) →</text>
+ <text x="44" y="46" fill="#d04040" font-size="12" font-family="monospace">x ↓</text>
+
+ <!-- camera eye -->
+ <circle cx="70" cy="200" r="10" fill="rgba(255,102,0,0.2)" stroke="#FF6600" stroke-width="2" filter="url(#glow)"/>
+ <circle cx="70" cy="200" r="3" fill="#FF6600"/>
+ <text x="70" y="232" fill="#FF8833" font-size="11" font-family="monospace" text-anchor="middle">camera</text>
+ <line x1="80" y1="200" x2="140" y2="200" stroke="#FF6600" stroke-width="1.5" stroke-dasharray="4 3"/>
+
+ <!-- near plane -->
+ <line x1="180" y1="55" x2="180" y2="262" stroke="#40b0d0" stroke-width="2" stroke-dasharray="6 3"/>
+ <text x="180" y="46" fill="#40b0d0" font-size="11" font-family="monospace" text-anchor="middle" filter="url(#glow)">near plane z = 1</text>
+
+ <!-- floor tiles seen edge-on (the floor is a row of quads at this x height) -->
+ <line x1="270" y1="200" x2="340" y2="200" stroke="#c05088" stroke-width="3"/>
+ <line x1="350" y1="200" x2="420" y2="200" stroke="#c05088" stroke-width="3"/>
+ <line x1="430" y1="200" x2="500" y2="200" stroke="#c05088" stroke-width="3"/>
+ <line x1="510" y1="200" x2="580" y2="200" stroke="#c05088" stroke-width="3"/>
+ <text x="460" y="186" fill="#c05088" font-size="11" font-family="monospace" text-anchor="middle">floor tiles</text>
+
+ <!-- the straddling tile: behind part discarded, front part kept -->
+ <line x1="130" y1="200" x2="180" y2="200" stroke="#FF4444" stroke-width="3" stroke-dasharray="4 3"/>
+ <line x1="180" y1="200" x2="260" y2="200" stroke="#39FF14" stroke-width="3.5" filter="url(#glow)"/>
+ <circle cx="180" cy="200" r="6" fill="#39FF14" filter="url(#glow)"/>
+ <text x="235" y="248" fill="#39FF14" font-size="11" font-family="monospace" text-anchor="middle">kept fragment</text>
+ <text x="128" y="248" fill="#FF4444" font-size="10" font-family="monospace" text-anchor="middle">cut away</text>
+
+ <!-- old behaviour callout -->
+ <text x="140" y="120" fill="#FF4444" font-size="11" font-family="monospace" text-anchor="middle">old: one vertex behind ⇒</text>
+ <text x="140" y="136" fill="#FF4444" font-size="11" font-family="monospace" text-anchor="middle">whole tile dropped</text>
+ <line x1="150" y1="142" x2="165" y2="192" stroke="#FF4444" stroke-width="1" stroke-dasharray="3 2"/>
+
+ <!-- new behaviour callout -->
+ <text x="330" y="120" fill="#39FF14" font-size="11" font-family="monospace" text-anchor="middle">new: clip at the plane,</text>
+ <text x="330" y="136" fill="#39FF14" font-size="11" font-family="monospace" text-anchor="middle">paint the surviving fragment</text>
+ <line x1="260" y1="142" x2="205" y2="192" stroke="#39FF14" stroke-width="1" stroke-dasharray="3 2"/>
+</svg>
--- /dev/null
+#+SETUPFILE: ~/.emacs.d/org-styles/html/darksun.theme
+#+TITLE: Near-Plane Clipping - Aukio 3D
+#+LANGUAGE: en
+#+LATEX_HEADER: \usepackage[margin=1.0in]{geometry}
+#+LATEX_HEADER: \usepackage{parskip}
+#+LATEX_HEADER: \usepackage[none]{hyphenat}
+
+#+OPTIONS: H:20 num:20
+#+OPTIONS: author:nil
+
+#+HTML_HEAD: <link rel="stylesheet" href="../style.css"/>
+
+[[file:../index.html#outline-container-understanding-3d-engine][<- Back to index]]
+
+* The problem
+:PROPERTIES:
+:CUSTOM_ID: the-problem
+:END:
+
+When the camera brushes against geometry — a floor tile under your
+feet, a wall you lean into — part of a polygon can end up *behind* the
+viewer while the rest stays in front. Perspective projection divides by
+depth (=screenX = x / z=), so a vertex at z ≤ 0 has no meaningful screen
+position at all.
+
+The naive way out — dropping any polygon that has even one vertex
+behind the camera — makes whole tiles vanish exactly when they are
+closest and largest on screen. Walking through the House demo, floor
+tiles blinked out of existence at the bottom of the frame:
+
+#+attr_html: :class responsive-img
+#+attr_latex: :width 640px
+[[file:near-clip-before.png]]
+
+*Aukio 3D* instead *clips the polygon against the near plane* and
+renders the surviving fragment. The same frame with clipping enabled —
+the floor is solid to the bottom edge:
+
+#+attr_html: :class responsive-img
+#+attr_latex: :width 640px
+[[file:near-clip-after.png]]
+
+Think of the camera plane as the edge of a table and the polygon as a
+sheet of paper partly hanging off it. Dropping the polygon means
+throwing away the whole sheet. Clipping takes scissors, cuts the sheet
+along the table edge, and keeps the part that lies on the table.
+
+#+INCLUDE: "Near plane straddle.svg" export html
+
+* Why not just clamp z?
+:PROPERTIES:
+:CUSTOM_ID: why-not-clamp-z
+:END:
+
+A tempting one-liner is to force every vertex to =z = max(z, epsilon)=
+and project anyway. It fails geometrically: a vertex at z = −50 clamped
+to z = 0.01 projects to a screen coordinate thousands of pixels away,
+*in the wrong direction* — the sign flip of the division mirrors it
+through the camera. The polygon smears into giant streaks across the
+frame instead of ending cleanly at the screen edge.
+
+Clipping produces the geometrically correct cut: the polygon's new edge
+lies exactly on the near plane, and everything the rasterizer receives
+has z > 0.
+
+* How the clipping works
+:PROPERTIES:
+:CUSTOM_ID: how-it-works
+:END:
+
+Clipping happens in *camera space*, after the transform stack has moved
+vertices relative to the viewer but *before* the perspective divide.
+The vertex loop is walked edge by edge (Sutherland-Hodgman style)
+against the plane =z = nearPlaneDistance=:
+
+1. An in-front vertex passes through unchanged.
+2. An edge that crosses the plane spawns a new vertex at the
+ intersection, with position, UV and normal all interpolated with the
+ same parameter =t=.
+3. A behind-plane vertex is skipped.
+
+#+INCLUDE: "Clip algorithm.svg" export html
+
+Interpolating UVs linearly along the 3D edge is exactly right for the
+perspective-correct texture mapper: the intersection vertex is a real
+point on the original edge, so its texture coordinate is the same blend
+of the endpoints' UVs. Textured fragments therefore show the correct
+texels right up to the cut, with no seam.
+
+Only a polygon with *all* vertices behind the plane is culled — the
+legitimate version of the old behavior.
+
+* From clipped loop to pixels
+:PROPERTIES:
+:CUSTOM_ID: from-clip-to-pixels
+:END:
+
+A convex N-gon crossing the plane clips to a single contiguous loop of
+at most N+1 vertices. For the triangle-based rasterizers this means a
+triangle can become a *quad*, which is painted as a two-triangle fan
+sharing the first vertex — exact, because the clip of a convex polygon
+stays convex:
+
+#+INCLUDE: "Fan triangulation.svg" export html
+
+Shape support:
+
+| Shape | Behavior when straddling |
+|--------------------+---------------------------------------------------|
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/basic/solidpolygon/SolidPolygon.html][SolidPolygon]] | Clipped loop painted as triangle fan |
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/basic/texturedpolygon/TexturedTriangle.html][TexturedTriangle]] | Fan-painted with interpolated UVs (also inherited by lightmapped GI fragments) |
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/basic/line/Line.html][Line]] | Shortened to the in-front endpoint + intersection |
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/basic/Billboard.html][Billboard]] | Single anchor point: culled when behind, as before |
+
+Implementation notes:
+
+- Clipped output is stored *per pipeline slot* on the shape
+ (=clippedVertices(ctx)=), so the triple-buffered pipeline can
+ transform frame N+1 while frame N is still painting.
+- Depth sorting and tile binning use the clipped vertices' average Z
+ and screen bounds — a clipped tile sorts as the fragment it became,
+ not as the polygon that reached behind you.
+- New intersection vertices exist only in camera space; they are
+ projected directly via
+ [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/math/Vertex.html#setCameraSpaceCoordinate(double,double,double,eu.svjatoslav.aukio.e3d.gui.RenderingContext)][Vertex.setCameraSpaceCoordinate()]],
+ bypassing the transform stack.
+
+* Configuration
+:PROPERTIES:
+:CUSTOM_ID: configuration
+:END:
+
+The near plane distance is a per-context knob, in world units:
+
+#+BEGIN_SRC java
+// Default is 1.0; smaller values let the camera press closer to
+// geometry before the scissors bite, at the cost of larger projected
+// coordinates for clipped fragments.
+viewPanel.getRenderingContext().nearPlaneDistance = 0.5;
+#+END_SRC
+
+* Related Classes
+:PROPERTIES:
+:CUSTOM_ID: related-classes
+:END:
+
+| Class | Purpose |
+|---------------------------+----------------------------------------------------------------|
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/AbstractCoordinateShape.html][AbstractCoordinateShape]] | Vertex-loop clipping in =transform()=, per-slot clip storage |
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/math/Vertex.html][Vertex]] | Camera-space projection for generated intersection vertices |
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/gui/RenderingContext.html][RenderingContext]] | Carries =nearPlaneDistance= |
--- /dev/null
+<svg viewBox="0 0 640 520" width="640" height="520" xmlns="http://www.w3.org/2000/svg">
+ <rect width="640" height="520" fill="#061018"/>
+ <polygon points="120,400 320,360 520,400 320,440" fill="rgba(180,150,30,0.1)" stroke="rgba(180,150,30,0.4)" stroke-width="2"/>
+ <line x1="180" y1="396" x2="460" y2="396" stroke="rgba(180,150,30,0.08)" stroke-width="1"/>
+ <line x1="220" y1="388" x2="420" y2="388" stroke="rgba(180,150,30,0.06)" stroke-width="1"/>
+ <line x1="320" y1="396" x2="320" y2="120" stroke="#b09020" stroke-width="5"/>
+ <polygon points="320,120 310,144 330,144" fill="#b09020"/>
+ <path d="M320,396 L320,356 L340,360" fill="none" stroke="rgba(180,150,30,0.5)" stroke-width="2"/>
+ <text x="336" y="112" fill="#b09020" font-size="26" font-weight="700" font-family="monospace">N̂</text>
+ <text x="336" y="144" fill="#bbb" font-size="18" font-family="monospace">unit normal</text>
+ <text x="336" y="172" fill="#bbb" font-size="18" font-family="monospace">(perpendicular</text>
+ <text x="336" y="196" fill="#bbb" font-size="18" font-family="monospace"> to surface)</text>
+ <circle cx="140" cy="120" r="28" fill="rgba(180,150,30,0.08)" stroke="rgba(180,150,30,0.3)" stroke-width="2"/>
+ <circle cx="140" cy="120" r="8" fill="rgba(180,150,30,0.6)"/>
+ <text x="112" y="84" fill="#bbb" font-size="18" font-family="monospace">Light</text>
+ <line x1="160" y1="136" x2="300" y2="340" stroke="rgba(180,150,30,0.2)" stroke-width="2" stroke-dasharray="8 6"/>
+ <text x="164" y="284" fill="rgba(180,150,30,0.5)" font-size="18" font-family="monospace">L · N = brightness</text>
+</svg>
--- /dev/null
+<svg viewBox="0 0 620 270" width="620" height="270" xmlns="http://www.w3.org/2000/svg">
+ <rect width="620" height="270" fill="#061018"/>
+
+ <!-- curvature curve -->
+ <polyline points="70.0,128.0 72.5,127.8 75.0,127.7 77.5,127.5 80.0,127.3 82.5,127.2 85.0,127.0 87.5,126.8 90.0,126.6 92.5,126.5 95.0,126.3 97.5,126.1 100.0,125.9 102.5,125.8 105.0,125.6 107.5,125.4 110.0,125.2 112.5,125.0 115.0,124.8 117.5,124.7 120.0,124.5 122.5,124.3 125.0,124.1 127.5,123.9 130.0,123.7 132.5,123.5 135.0,123.3 137.5,123.1 140.0,122.9 142.5,122.7 145.0,122.5 147.5,122.3 150.0,122.1 152.5,121.9 155.0,121.7 157.5,121.5 160.0,121.3 162.5,121.1 165.0,120.9 167.5,120.7 170.0,120.5 172.5,120.2 175.0,120.0 177.5,119.8 180.0,119.6 182.5,119.4 185.0,119.1 187.5,118.9 190.0,118.7 192.5,118.5 195.0,118.2 197.5,118.0 200.0,117.8 202.5,117.5 205.0,117.3 207.5,117.1 210.0,116.8 212.5,116.6 215.0,116.3 217.5,116.1 220.0,115.9 222.5,115.6 225.0,115.4 227.5,115.1 230.0,114.9 232.5,114.6 235.0,114.3 237.5,114.1 240.0,113.8 242.5,113.6 245.0,113.3 247.5,113.0 250.0,112.8 252.5,112.5 255.0,112.2 257.5,111.9 260.0,111.7 262.5,111.4 265.0,111.1 267.5,110.8 270.0,110.5 272.5,110.2 275.0,109.9 277.5,109.7 280.0,109.4 282.5,109.1 285.0,108.8 287.5,108.5 290.0,108.2 292.5,107.8 295.0,107.5 297.5,107.2 300.0,106.9 302.5,106.6 305.0,106.3 307.5,105.9 310.0,105.6 312.5,105.3 315.0,105.0 317.5,104.6 320.0,104.3 322.5,103.9 325.0,103.6 327.5,103.3 330.0,102.9 332.5,102.6 335.0,102.2 337.5,101.8 340.0,101.5 342.5,101.1 345.0,100.7 347.5,100.4 350.0,100.0 352.5,99.6 355.0,99.2 357.5,98.9 360.0,98.5 362.5,98.1 365.0,97.7 367.5,97.3 370.0,96.9 372.5,96.5 375.0,96.1 377.5,95.6 380.0,95.2 382.5,94.8 385.0,94.4 387.5,93.9 390.0,93.5 392.5,93.1 395.0,92.6 397.5,92.2 400.0,91.7 402.5,91.3 405.0,90.8 407.5,90.3 410.0,89.9 412.5,89.4 415.0,88.9 417.5,88.4 420.0,87.9 422.5,87.4 425.0,86.9 427.5,86.4 430.0,85.9 432.5,85.4 435.0,84.9 437.5,84.3 440.0,83.8 442.5,83.3 445.0,82.7 447.5,82.2 450.0,81.6 452.5,81.1 455.0,80.5 457.5,79.9 460.0,79.3 462.5,78.7 465.0,78.1 467.5,77.5 470.0,76.9 472.5,76.3 475.0,75.7 477.5,75.0 480.0,74.4 482.5,73.8 485.0,73.1 487.5,72.4 490.0,71.8 492.5,71.1 495.0,70.4 497.5,69.7 500.0,69.0 502.5,68.3 505.0,67.6 507.5,66.8 510.0,66.1 512.5,65.4 515.0,64.6 517.5,63.8 520.0,63.0 522.5,62.3 525.0,61.5 527.5,60.6 530.0,59.8 532.5,59.0 535.0,58.1 537.5,57.3 540.0,56.4 542.5,55.5 545.0,54.7 547.5,53.7 550.0,52.8 552.5,51.9 555.0,51.0 557.5,50.0 560.0,49.0 562.5,48.0 565.0,47.0 567.5,46.0 570.0,45.0" fill="none" stroke="#c05088" stroke-width="2"/>
+ <text x="80.0" y="34" fill="#c05088" font-size="10" font-family="monospace">perspective curvature → rises toward the far end</text>
+
+ <!-- span bar with adaptive blocks -->
+ <rect x="70.0" y="150" width="80.0" height="34" fill="rgba(48,160,80,0.45)" stroke="#30a050" stroke-width="1"/>
+ <rect x="150.0" y="150" width="80.0" height="34" fill="rgba(48,160,80,0.45)" stroke="#30a050" stroke-width="1"/>
+ <rect x="230.0" y="150" width="80.0" height="34" fill="rgba(48,160,80,0.45)" stroke="#30a050" stroke-width="1"/>
+ <rect x="310.0" y="150" width="40.0" height="34" fill="rgba(221,153,0,0.45)" stroke="#dd9900" stroke-width="1"/>
+ <rect x="350.0" y="150" width="40.0" height="34" fill="rgba(221,153,0,0.45)" stroke="#dd9900" stroke-width="1"/>
+ <rect x="390.0" y="150" width="20.0" height="34" fill="rgba(255,102,0,0.45)" stroke="#FF6600" stroke-width="1"/>
+ <rect x="410.0" y="150" width="20.0" height="34" fill="rgba(255,102,0,0.45)" stroke="#FF6600" stroke-width="1"/>
+ <rect x="430.0" y="150" width="10.0" height="34" fill="rgba(208,64,64,0.45)" stroke="#d04040" stroke-width="1"/>
+ <rect x="440.0" y="150" width="10.0" height="34" fill="rgba(208,64,64,0.45)" stroke="#d04040" stroke-width="1"/>
+ <rect x="450.0" y="150" width="10.0" height="34" fill="rgba(208,64,64,0.45)" stroke="#d04040" stroke-width="1"/>
+ <rect x="460.0" y="150" width="10.0" height="34" fill="rgba(208,64,64,0.45)" stroke="#d04040" stroke-width="1"/>
+ <rect x="470.0" y="150" width="10.0" height="34" fill="rgba(208,64,64,0.45)" stroke="#d04040" stroke-width="1"/>
+ <rect x="480.0" y="150" width="10.0" height="34" fill="rgba(208,64,64,0.45)" stroke="#d04040" stroke-width="1"/>
+ <rect x="490.0" y="150" width="10.0" height="34" fill="rgba(208,64,64,0.45)" stroke="#d04040" stroke-width="1"/>
+ <rect x="500.0" y="150" width="10.0" height="34" fill="rgba(208,64,64,0.45)" stroke="#d04040" stroke-width="1"/>
+ <rect x="510.0" y="150" width="10.0" height="34" fill="rgba(208,64,64,0.45)" stroke="#d04040" stroke-width="1"/>
+ <rect x="520.0" y="150" width="10.0" height="34" fill="rgba(208,64,64,0.45)" stroke="#d04040" stroke-width="1"/>
+ <rect x="530.0" y="150" width="10.0" height="34" fill="rgba(208,64,64,0.45)" stroke="#d04040" stroke-width="1"/>
+ <rect x="540.0" y="150" width="10.0" height="34" fill="rgba(208,64,64,0.45)" stroke="#d04040" stroke-width="1"/>
+ <rect x="550.0" y="150" width="10.0" height="34" fill="rgba(208,64,64,0.45)" stroke="#d04040" stroke-width="1"/>
+ <rect x="560.0" y="150" width="10.0" height="34" fill="rgba(208,64,64,0.45)" stroke="#d04040" stroke-width="1"/>
+ <line x1="70.0" y1="146" x2="70.0" y2="150" stroke="#aaa" stroke-width="1"/>
+ <line x1="150.0" y1="146" x2="150.0" y2="150" stroke="#aaa" stroke-width="1"/>
+ <line x1="230.0" y1="146" x2="230.0" y2="150" stroke="#aaa" stroke-width="1"/>
+ <line x1="310.0" y1="146" x2="310.0" y2="150" stroke="#aaa" stroke-width="1"/>
+ <line x1="350.0" y1="146" x2="350.0" y2="150" stroke="#aaa" stroke-width="1"/>
+ <line x1="390.0" y1="146" x2="390.0" y2="150" stroke="#aaa" stroke-width="1"/>
+ <line x1="410.0" y1="146" x2="410.0" y2="150" stroke="#aaa" stroke-width="1"/>
+ <line x1="430.0" y1="146" x2="430.0" y2="150" stroke="#aaa" stroke-width="1"/>
+ <line x1="440.0" y1="146" x2="440.0" y2="150" stroke="#aaa" stroke-width="1"/>
+ <line x1="450.0" y1="146" x2="450.0" y2="150" stroke="#aaa" stroke-width="1"/>
+ <line x1="460.0" y1="146" x2="460.0" y2="150" stroke="#aaa" stroke-width="1"/>
+ <line x1="470.0" y1="146" x2="470.0" y2="150" stroke="#aaa" stroke-width="1"/>
+ <line x1="480.0" y1="146" x2="480.0" y2="150" stroke="#aaa" stroke-width="1"/>
+ <line x1="490.0" y1="146" x2="490.0" y2="150" stroke="#aaa" stroke-width="1"/>
+ <line x1="500.0" y1="146" x2="500.0" y2="150" stroke="#aaa" stroke-width="1"/>
+ <line x1="510.0" y1="146" x2="510.0" y2="150" stroke="#aaa" stroke-width="1"/>
+ <line x1="520.0" y1="146" x2="520.0" y2="150" stroke="#aaa" stroke-width="1"/>
+ <line x1="530.0" y1="146" x2="530.0" y2="150" stroke="#aaa" stroke-width="1"/>
+ <line x1="540.0" y1="146" x2="540.0" y2="150" stroke="#aaa" stroke-width="1"/>
+ <line x1="550.0" y1="146" x2="550.0" y2="150" stroke="#aaa" stroke-width="1"/>
+ <line x1="560.0" y1="146" x2="560.0" y2="150" stroke="#aaa" stroke-width="1"/>
+ <line x1="570.0" y1="146" x2="570.0" y2="150" stroke="#aaa" stroke-width="1"/>
+ <text x="190.0" y="202" fill="#30a050" font-size="11" font-family="monospace" text-anchor="middle">16 px</text>
+ <text x="350.0" y="218" fill="#dd9900" font-size="11" font-family="monospace" text-anchor="middle">8 px</text>
+ <text x="410.0" y="202" fill="#FF6600" font-size="11" font-family="monospace" text-anchor="middle">4 px</text>
+ <text x="500.0" y="218" fill="#d04040" font-size="11" font-family="monospace" text-anchor="middle">2 px</text>
+
+ <text x="70" y="248" fill="#666" font-size="10" font-family="monospace">one scanline, 100 px →</text>
+ <text x="570" y="248" fill="#666" font-size="10" font-family="monospace" text-anchor="end">grazing-angle floor, far side</text>
+</svg>
--- /dev/null
+<svg viewBox="0 0 620 280" width="620" height="280" xmlns="http://www.w3.org/2000/svg">
+ <rect width="620" height="280" fill="#061018"/>
+
+ <!-- grid -->
+ <line x1="70" y1="185.0" x2="570" y2="185.0" stroke="#1a3a4a" stroke-width="1"/>
+ <line x1="70" y1="140.0" x2="570" y2="140.0" stroke="#1a3a4a" stroke-width="1"/>
+ <line x1="70" y1="95.0" x2="570" y2="95.0" stroke="#1a3a4a" stroke-width="1"/>
+ <line x1="195.0" y1="50" x2="195.0" y2="230" stroke="#1a3a4a" stroke-width="1"/>
+ <line x1="320.0" y1="50" x2="320.0" y2="230" stroke="#1a3a4a" stroke-width="1"/>
+ <line x1="445.0" y1="50" x2="445.0" y2="230" stroke="#1a3a4a" stroke-width="1"/>
+
+ <!-- axes -->
+ <line x1="70" y1="230" x2="570" y2="230" stroke="#445566" stroke-width="1.5"/>
+ <line x1="70" y1="230" x2="70" y2="50" stroke="#445566" stroke-width="1.5"/>
+ <text x="570" y="252" fill="#666" font-size="10" font-family="monospace" text-anchor="end">screen pixel →</text>
+ <text x="62" y="42" fill="#666" font-size="10" font-family="monospace" text-anchor="start">texel u ↑</text>
+
+ <!-- affine (straight, wrong) -->
+ <polyline points="70.0,230.0 570.0,50.0" fill="none" stroke="#c05088" stroke-width="2" stroke-dasharray="6 4"/>
+
+ <!-- exact perspective curve -->
+ <polyline points="70.0,230.0 72.5,229.6 75.0,229.3 77.5,228.9 80.0,228.5 82.5,228.2 85.0,227.8 87.5,227.4 90.0,227.0 92.5,226.7 95.0,226.3 97.5,225.9 100.0,225.5 102.5,225.1 105.0,224.7 107.5,224.3 110.0,223.9 112.5,223.6 115.0,223.2 117.5,222.7 120.0,222.3 122.5,221.9 125.0,221.5 127.5,221.1 130.0,220.7 132.5,220.3 135.0,219.8 137.5,219.4 140.0,219.0 142.5,218.6 145.0,218.1 147.5,217.7 150.0,217.3 152.5,216.8 155.0,216.4 157.5,215.9 160.0,215.5 162.5,215.0 165.0,214.6 167.5,214.1 170.0,213.6 172.5,213.2 175.0,212.7 177.5,212.2 180.0,211.8 182.5,211.3 185.0,210.8 187.5,210.3 190.0,209.8 192.5,209.3 195.0,208.8 197.5,208.3 200.0,207.8 202.5,207.3 205.0,206.8 207.5,206.3 210.0,205.8 212.5,205.2 215.0,204.7 217.5,204.2 220.0,203.7 222.5,203.1 225.0,202.6 227.5,202.0 230.0,201.5 232.5,200.9 235.0,200.4 237.5,199.8 240.0,199.2 242.5,198.7 245.0,198.1 247.5,197.5 250.0,196.9 252.5,196.4 255.0,195.8 257.5,195.2 260.0,194.6 262.5,194.0 265.0,193.3 267.5,192.7 270.0,192.1 272.5,191.5 275.0,190.8 277.5,190.2 280.0,189.6 282.5,188.9 285.0,188.3 287.5,187.6 290.0,187.0 292.5,186.3 295.0,185.6 297.5,184.9 300.0,184.3 302.5,183.6 305.0,182.9 307.5,182.2 310.0,181.5 312.5,180.7 315.0,180.0 317.5,179.3 320.0,178.6 322.5,177.8 325.0,177.1 327.5,176.3 330.0,175.6 332.5,174.8 335.0,174.0 337.5,173.3 340.0,172.5 342.5,171.7 345.0,170.9 347.5,170.1 350.0,169.3 352.5,168.5 355.0,167.6 357.5,166.8 360.0,166.0 362.5,165.1 365.0,164.2 367.5,163.4 370.0,162.5 372.5,161.6 375.0,160.7 377.5,159.8 380.0,158.9 382.5,158.0 385.0,157.1 387.5,156.1 390.0,155.2 392.5,154.2 395.0,153.3 397.5,152.3 400.0,151.3 402.5,150.3 405.0,149.3 407.5,148.3 410.0,147.3 412.5,146.3 415.0,145.2 417.5,144.2 420.0,143.1 422.5,142.0 425.0,140.9 427.5,139.8 430.0,138.7 432.5,137.6 435.0,136.5 437.5,135.3 440.0,134.2 442.5,133.0 445.0,131.8 447.5,130.6 450.0,129.4 452.5,128.2 455.0,127.0 457.5,125.7 460.0,124.4 462.5,123.2 465.0,121.9 467.5,120.6 470.0,119.2 472.5,117.9 475.0,116.5 477.5,115.2 480.0,113.8 482.5,112.4 485.0,111.0 487.5,109.5 490.0,108.1 492.5,106.6 495.0,105.1 497.5,103.6 500.0,102.1 502.5,100.5 505.0,99.0 507.5,97.4 510.0,95.8 512.5,94.1 515.0,92.5 517.5,90.8 520.0,89.1 522.5,87.4 525.0,85.7 527.5,83.9 530.0,82.1 532.5,80.3 535.0,78.5 537.5,76.7 540.0,74.8 542.5,72.9 545.0,70.9 547.5,69.0 550.0,67.0 552.5,65.0 555.0,62.9 557.5,60.8 560.0,58.7 562.5,56.6 565.0,54.4 567.5,52.2 570.0,50.0" fill="none" stroke="#39FF14" stroke-width="2"/>
+
+ <!-- subdivided correction -->
+ <polyline points="70.0,230.0 150.0,217.3 230.0,201.5 310.0,181.5 390.0,155.2 470.0,119.2 570.0,50.0" fill="none" stroke="#FF6600" stroke-width="2"/>
+ <circle cx="70.0" cy="230.0" r="3.5" fill="#FF6600"/>
+ <circle cx="150.0" cy="217.3" r="3.5" fill="#FF6600"/>
+ <circle cx="230.0" cy="201.5" r="3.5" fill="#FF6600"/>
+ <circle cx="310.0" cy="181.5" r="3.5" fill="#FF6600"/>
+ <circle cx="390.0" cy="155.2" r="3.5" fill="#FF6600"/>
+ <circle cx="470.0" cy="119.2" r="3.5" fill="#FF6600"/>
+ <circle cx="570.0" cy="50.0" r="3.5" fill="#FF6600"/>
+
+ <!-- legend -->
+ <line x1="380" y1="20" x2="410" y2="20" stroke="#39FF14" stroke-width="2"/>
+ <text x="416" y="24" fill="#39FF14" font-size="10" font-family="monospace">exact perspective</text>
+ <line x1="380" y1="38" x2="410" y2="38" stroke="#FF6600" stroke-width="2"/>
+ <text x="416" y="42" fill="#FF6600" font-size="10" font-family="monospace">corrected every 16 px</text>
+ <line x1="380" y1="56" x2="410" y2="56" stroke="#c05088" stroke-width="2" stroke-dasharray="6 4"/>
+ <text x="416" y="60" fill="#c05088" font-size="10" font-family="monospace">plain affine</text>
+</svg>
--- /dev/null
+#+SETUPFILE: ~/.emacs.d/org-styles/html/darksun.theme
+#+TITLE: Perspective-Correct Textures - Aukio 3D
+#+LANGUAGE: en
+#+LATEX_HEADER: \usepackage[margin=1.0in]{geometry}
+#+LATEX_HEADER: \usepackage{parskip}
+#+LATEX_HEADER: \usepackage[none]{hyphenat}
+
+#+OPTIONS: H:20 num:20
+#+OPTIONS: author:nil
+
+#+HTML_HEAD: <link rel="stylesheet" href="../style.css"/>
+
+[[file:../index.html#outline-container-understanding-3d-engine][<- Back to index]]
+
+* The problem
+:PROPERTIES:
+:CUSTOM_ID: introduction
+:ID: a2b3c4d5-e6f7-8901-bcde-f23456789012
+:END:
+
+When a textured polygon is rendered at an angle to the viewer, naive
+linear interpolation of texture coordinates produces visible
+distortion.
+
+Consider a large textured floor extending toward the horizon. Without
+perspective correction, the texture appears to "swim" or distort
+because the texture coordinates are interpolated linearly across
+screen space, not accounting for depth.
+
+#+attr_html: :class responsive-img
+#+attr_latex: :width 1000px
+[[file:Affine distortion.png]]
+
+The *Aukio 3D* engine solves this with *subdivided perspective
+correction* inside the scanline rasterizer — the same technique Quake
+used.
+
+* How perspective correction works
+:PROPERTIES:
+:CUSTOM_ID: how-perspective-correction-works
+:END:
+
+Texture coordinates (u, v) are not linear in screen space, so they
+cannot simply be stepped per pixel. But divide them by depth and they
+become linear: *(u/z, v/z, 1/z) all interpolate linearly* across the
+triangle in screen space.
+
+The rasterizer exploits this:
+
+1. Compute (u/z, v/z, 1/z) at each vertex
+2. Interpolate all three across the scanline with plain additions
+3. Every N pixels, recover the exact texture coordinate with one
+ division: =u = (u/z) / (1/z)=
+4. Between correction points, step u/v affinely toward the next exact
+ point
+
+#+INCLUDE: "Scanline correction.svg" export html
+
+The orange polyline hugs the exact green curve: within each 16-pixel
+block it is a straight line, but every block starts exactly on the
+curve. The dashed pink line is plain affine interpolation — visibly
+wrong everywhere except the endpoints.
+
+Think of it like walking with a map that is slightly distorted: you
+walk in a straight line, but every 16 steps you check a landmark and
+correct your course. The correction (a division) costs something, so
+you do it every N pixels instead of every pixel — the divide cost is
+amortized to 1/16th of a per-pixel-correct rasterizer.
+
+#+BEGIN_SRC java
+// Per scanline (simplified from drawHorizontalLinePerspective):
+while (done < span) {
+ // Advance (u/z, v/z, 1/z) to the end of this block
+ su += dsu * block; sv += dsv * block; sw += dsw * block;
+ double txNext = su / sw; // one reciprocal = exact texture position
+ double tyNext = sv / sw;
+
+ // Step affinely through the block
+ double txStep = (txNext - tx) / block;
+ double tyStep = (tyNext - ty) / block;
+ for (int i = 0; i < block; i++) {
+ plot(x++, texture.sample(tx, ty));
+ tx += txStep; ty += tyStep;
+ }
+ done += block;
+}
+#+END_SRC
+
+** Adaptive correction interval
+:PROPERTIES:
+:CUSTOM_ID: adaptive-correction-interval
+:END:
+
+Quake used a fixed 16-pixel interval. This engine keeps 16 as the
+default but *shrinks the interval when the error bound demands it*.
+
+The error of affine stepping within a block grows with both the
+texture gradient (texels per pixel) and the perspective curvature
+(how fast 1/z changes across the span). Each scanline computes
+
+#+BEGIN_EXAMPLE
+error(texels) ≈ texelRate · interval² · k / 2
+#+END_EXAMPLE
+
+where =k = |d(1/z)| / min(1/z)= is the per-pixel relative depth change,
+and picks the largest power-of-two interval from the ladder 16, 8, 4,
+2, 1 that keeps the bound under half a texel. Flat, gently angled
+spans keep the fast 16-pixel cadence; a floor tile seen at a grazing
+angle drops to shorter intervals exactly where the curvature is high.
+
+#+INCLUDE: "Adaptive interval.svg" export html
+
+** When affine is good enough
+:PROPERTIES:
+:CUSTOM_ID: when-affine-good-enough
+:END:
+
+For small or nearly flat triangles, plain affine mapping is already
+within half a texel of exact perspective, so the perspective setup is
+skipped entirely. The test compares the texture range the triangle
+covers against its depth variation:
+
+#+BEGIN_EXAMPLE
+affine is sufficient when texelSpan · (zMax/zMin − 1) < 2
+#+END_EXAMPLE
+
+Note the criterion is the *texel* span, not the pixel size — a tiny
+on-screen triangle can still map many texels into few pixels. Distant
+clusters of small triangles (a common case) all render through the
+cheaper affine path.
+
+Triangles straddling the near plane (any vertex closer than z = 0.001)
+also fall back to affine, because 1/z interpolation is invalid there.
+
+** Toggling the correction
+:PROPERTIES:
+:CUSTOM_ID: toggling-the-correction
+:END:
+
+Perspective correction can be switched off globally for A/B comparison
+or debugging:
+
+#+BEGIN_SRC java
+TexturedTriangle.setPerspectiveCorrectionEnabled(false); // plain affine everywhere
+#+END_SRC
+
+With correction disabled, large triangles at steep angles visibly warp
+— useful for demonstrating what the correction actually buys.
+
+* Mipmap selection
+:PROPERTIES:
+:CUSTOM_ID: mipmap-selection
+:END:
+
+Perspective correction fixes *where* a texel is sampled; mipmapping
+decides *which resolution* to sample from. Each triangle estimates its
+screen-pixels-per-texel ratio from edge lengths:
+
+#+BEGIN_EXAMPLE
+scaleFactor = (sum of screen edge lengths) / (sum of UV edge lengths) · 1.2
+#+END_EXAMPLE
+
+[[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/texture/Texture.html#getMipmapForScale(double)][Texture.getMipmapForScale()]]
+then picks the lazily-generated mipmap level closest to that scale:
+halved resolutions when the texture is minified, doubled when strongly
+magnified. Sampling a smaller mipmap under minification both speeds up
+rendering (better cache behavior) and reduces aliasing.
+
+* Related Classes
+:PROPERTIES:
+:CUSTOM_ID: related-classes
+:END:
+
+| Class | Purpose |
+|-------------------------------+--------------------------------------------------------------------|
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/basic/texturedpolygon/TexturedTriangle.html][TexturedTriangle]] | Textured triangle with perspective-correct and SDF rendering paths |
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/basic/texturedpolygon/PerspectiveBorderInterpolator.html][PerspectiveBorderInterpolator]] | Edge walker interpolating (u/z, v/z, 1/z) along triangle borders |
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/basic/texturedpolygon/PolygonBorderInterpolator.html][PolygonBorderInterpolator]] | Edge walker for plain affine mapping |
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/texture/Texture.html][Texture]] | Mipmap container; also carries the SDF mask and color layers |
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/texture/TextureBitmap.html][TextureBitmap]] | Raw pixel array for one mipmap level |
+
+*See also:*
+
+- [[file:../SDF textures/][SDF textures]] — signed-distance-field glyph rendering, the
+ alternative sampling path in =TexturedTriangle= that reuses the same
+ perspective-correct interpolation for crisp text at any angle.
--- /dev/null
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+
+
+<!-- Divider -->
+<line x1="340" y1="30" x2="340" y2="310" stroke="#1a2a38" stroke-width="1" mask="url(#imagine-text-gaps-eqff6y)" style="fill:rgb(0, 0, 0);stroke:rgb(26, 42, 56);color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+
+<!-- ===== LEFT: Point3D ===== -->
+<text x="170" y="36" text-anchor="middle" fill="#2070c0" font-size="15" font-weight="700" font-family="monospace" style="fill:rgb(32, 112, 192);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:15px;font-weight:700;text-anchor:middle;dominant-baseline:auto">Point3D</text>
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+<text x="186" y="144" fill="#2070c0" font-size="13" font-weight="700" font-family="monospace" style="fill:rgb(32, 112, 192);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:13px;font-weight:700;text-anchor:start;dominant-baseline:auto">(x, y, z)</text>
+
+<!-- Radial leader lines + labels — 6 directions, all consistent -->
+<!-- Top-left: distance -->
+<line x1="155" y1="132" x2="68" y2="82" stroke="#2a3a4a" stroke-width="0.5" stroke-dasharray="3 2" mask="url(#imagine-text-gaps-eqff6y)" style="fill:rgb(0, 0, 0);stroke:rgb(42, 58, 74);color:rgb(251, 251, 254);stroke-width:0.5px;stroke-dasharray:3px, 2px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+<circle cx="68" cy="82" r="1.5" fill="#2a3a4a" style="fill:rgb(42, 58, 74);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+<text x="96.23" y="78" text-anchor="end" fill="#445566" font-size="10" font-family="monospace" style="fill:rgb(68, 85, 102);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:10px;font-weight:400;text-anchor:end;dominant-baseline:auto">.getDistanceTo()</text>
+
+<!-- Top-right: rotate -->
+<line x1="188" y1="134" x2="268" y2="82" stroke="#2a3a4a" stroke-width="0.5" stroke-dasharray="3 2" mask="url(#imagine-text-gaps-eqff6y)" style="fill:rgb(0, 0, 0);stroke:rgb(42, 58, 74);color:rgb(251, 251, 254);stroke-width:0.5px;stroke-dasharray:3px, 2px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+<circle cx="268" cy="82" r="1.5" fill="#2a3a4a" style="fill:rgb(42, 58, 74);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+<text x="272" y="78" fill="#445566" font-size="10" font-family="monospace" style="fill:rgb(68, 85, 102);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:10px;font-weight:400;text-anchor:start;dominant-baseline:auto">.rotate()</text>
+
+<!-- Left: add/subtract -->
+<line x1="150" y1="148" x2="58" y2="148" stroke="#2a3a4a" stroke-width="0.5" stroke-dasharray="3 2" mask="url(#imagine-text-gaps-eqff6y)" style="fill:rgb(0, 0, 0);stroke:rgb(42, 58, 74);color:rgb(251, 251, 254);stroke-width:0.5px;stroke-dasharray:3px, 2px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+<circle cx="58" cy="148" r="1.5" fill="#2a3a4a" style="fill:rgb(42, 58, 74);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+<text x="66.16" y="144" text-anchor="end" fill="#445566" font-size="10" font-family="monospace" style="fill:rgb(68, 85, 102);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:10px;font-weight:400;text-anchor:end;dominant-baseline:auto">.add()</text>
+<text x="66.16" y="158" text-anchor="end" fill="#445566" font-size="10" font-family="monospace" style="fill:rgb(68, 85, 102);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:10px;font-weight:400;text-anchor:end;dominant-baseline:auto">.subtract()</text>
+
+<!-- Right: crossProduct -->
+<line x1="190" y1="148" x2="268" y2="148" stroke="#2a3a4a" stroke-width="0.5" stroke-dasharray="3 2" mask="url(#imagine-text-gaps-eqff6y)" style="fill:rgb(0, 0, 0);stroke:rgb(42, 58, 74);color:rgb(251, 251, 254);stroke-width:0.5px;stroke-dasharray:3px, 2px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+<circle cx="268" cy="148" r="1.5" fill="#2a3a4a" style="fill:rgb(42, 58, 74);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+<text x="272" y="152" fill="#445566" font-size="10" font-family="monospace" style="fill:rgb(68, 85, 102);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:10px;font-weight:400;text-anchor:start;dominant-baseline:auto">.crossProduct()</text>
+
+<!-- Bottom-left: unit/dot -->
+<line x1="155" y1="164" x2="68" y2="214" stroke="#2a3a4a" stroke-width="0.5" stroke-dasharray="3 2" mask="url(#imagine-text-gaps-eqff6y)" style="fill:rgb(0, 0, 0);stroke:rgb(42, 58, 74);color:rgb(251, 251, 254);stroke-width:0.5px;stroke-dasharray:3px, 2px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+<circle cx="68" cy="214" r="1.5" fill="#2a3a4a" style="fill:rgb(42, 58, 74);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+<text x="96.23" y="210" text-anchor="end" fill="#445566" font-size="10" font-family="monospace" style="fill:rgb(68, 85, 102);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:10px;font-weight:400;text-anchor:end;dominant-baseline:auto">.unit()</text>
+<text x="96.23" y="224" text-anchor="end" fill="#445566" font-size="10" font-family="monospace" style="fill:rgb(68, 85, 102);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:10px;font-weight:400;text-anchor:end;dominant-baseline:auto">.dot()</text>
+
+<!-- Bottom-right: multiply -->
+<line x1="188" y1="162" x2="268" y2="214" stroke="#2a3a4a" stroke-width="0.5" stroke-dasharray="3 2" style="fill:rgb(0, 0, 0);stroke:rgb(42, 58, 74);color:rgb(251, 251, 254);stroke-width:0.5px;stroke-dasharray:3px, 2px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+<circle cx="268" cy="214" r="1.5" fill="#2a3a4a" style="fill:rgb(42, 58, 74);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+<text x="272" y="218" fill="#445566" font-size="10" font-family="monospace" style="fill:rgb(68, 85, 102);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:10px;font-weight:400;text-anchor:start;dominant-baseline:auto">.multiply()</text>
+
+<!-- Summary -->
+<text x="170" y="280" text-anchor="middle" fill="#556677" font-size="10" font-family="monospace" style="fill:rgb(85, 102, 119);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:10px;font-weight:400;text-anchor:middle;dominant-baseline:auto">Mutable, fluent API</text>
+<text x="170" y="296" text-anchor="middle" fill="#556677" font-size="10" font-family="monospace" style="fill:rgb(85, 102, 119);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:10px;font-weight:400;text-anchor:middle;dominant-baseline:auto">Positions, vectors, math</text>
+
+<!-- ===== RIGHT: Vertex ===== -->
+<text x="510" y="36" text-anchor="middle" fill="#c05088" font-size="15" font-weight="700" font-family="monospace" style="fill:rgb(192, 80, 136);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:15px;font-weight:700;text-anchor:middle;dominant-baseline:auto">Vertex</text>
+<text x="510" y="52" text-anchor="middle" fill="#556677" font-size="10" font-family="monospace" style="fill:rgb(85, 102, 119);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:10px;font-weight:400;text-anchor:middle;dominant-baseline:auto">rendering-ready wrapper</text>
+
+<!-- Outer wrapper box -->
+<rect x="375" y="68" width="270" height="230" rx="6" fill="rgba(192,80,136,0.04)" stroke="rgba(192,80,136,0.2)" stroke-width="0.5" style="fill:rgba(192, 80, 136, 0.04);stroke:rgba(192, 80, 136, 0.2);color:rgb(251, 251, 254);stroke-width:0.5px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+
+<!-- coordinate (Point3D) -->
+<rect x="390" y="82" width="240" height="32" rx="4" fill="rgba(56,140,248,0.1)" stroke="rgba(56,140,248,0.3)" stroke-width="0.5" style="fill:rgba(56, 140, 248, 0.1);stroke:rgba(56, 140, 248, 0.3);color:rgb(251, 251, 254);stroke-width:0.5px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+<circle cx="406" cy="98" r="3" fill="#2070c0" style="fill:rgb(32, 112, 192);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+<text x="418" y="102" fill="#2070c0" font-size="11" font-weight="700" font-family="monospace" style="fill:rgb(32, 112, 192);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:11px;font-weight:700;text-anchor:start;dominant-baseline:auto">coordinate</text>
+<text x="548" y="102" fill="#445566" font-size="9" font-family="monospace" style="fill:rgb(68, 85, 102);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:9px;font-weight:400;text-anchor:start;dominant-baseline:auto">Point3D</text>
+
+<!-- "wraps" arrow -->
+<line x1="340" y1="148" x2="388" y2="98" stroke="#2a3a4a" stroke-width="0.5" stroke-dasharray="4 3" mask="url(#imagine-text-gaps-eqff6y)" style="fill:rgb(0, 0, 0);stroke:rgb(42, 58, 74);color:rgb(251, 251, 254);stroke-width:0.5px;stroke-dasharray:4px, 3px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+<text x="356" y="118" fill="#334455" font-size="8" font-family="monospace" transform="rotate(-30 356 118)" style="fill:rgb(51, 68, 85);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:8px;font-weight:400;text-anchor:start;dominant-baseline:auto">wraps</text>
+
+<!-- transformedCoordinate -->
+<rect x="390" y="122" width="240" height="32" rx="4" fill="rgba(48,160,80,0.08)" stroke="rgba(48,160,80,0.25)" stroke-width="0.5" style="fill:rgba(48, 160, 80, 0.08);stroke:rgba(48, 160, 80, 0.25);color:rgb(251, 251, 254);stroke-width:0.5px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+<text x="406" y="142" fill="#30a050" font-size="11" font-weight="700" font-family="monospace" style="fill:rgb(48, 160, 80);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:11px;font-weight:700;text-anchor:start;dominant-baseline:auto">transformedCoordinate</text>
+
+<!-- onScreenCoordinate -->
+<rect x="390" y="162" width="240" height="32" rx="4" fill="rgba(255,102,0,0.08)" stroke="rgba(255,102,0,0.25)" stroke-width="0.5" style="fill:rgba(255, 102, 0, 0.08);stroke:rgba(255, 102, 0, 0.25);color:rgb(251, 251, 254);stroke-width:0.5px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+<text x="406" y="182" fill="#FF6600" font-size="11" font-weight="700" font-family="monospace" style="fill:rgb(255, 102, 0);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:11px;font-weight:700;text-anchor:start;dominant-baseline:auto">onScreenCoordinate</text>
+
+<!-- textureCoordinate -->
+<rect x="390" y="202" width="240" height="32" rx="4" fill="rgba(176,144,32,0.08)" stroke="rgba(176,144,32,0.25)" stroke-width="0.5" style="fill:rgba(176, 144, 32, 0.08);stroke:rgba(176, 144, 32, 0.25);color:rgb(251, 251, 254);stroke-width:0.5px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+<text x="406" y="222" fill="#b09020" font-size="11" font-weight="700" font-family="monospace" style="fill:rgb(176, 144, 32);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:11px;font-weight:700;text-anchor:start;dominant-baseline:auto">textureCoordinate</text>
+<text x="598" y="222" fill="#445566" font-size="9" font-family="monospace" style="fill:rgb(68, 85, 102);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:9px;font-weight:400;text-anchor:start;dominant-baseline:auto">UV</text>
+
+<!-- normal -->
+<rect x="390" y="242" width="240" height="32" rx="4" fill="rgba(80,96,192,0.08)" stroke="rgba(80,96,192,0.25)" stroke-width="0.5" style="fill:rgba(80, 96, 192, 0.08);stroke:rgba(80, 96, 192, 0.25);color:rgb(251, 251, 254);stroke-width:0.5px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+<text x="406" y="262" fill="#5060c0" font-size="11" font-weight="700" font-family="monospace" style="fill:rgb(80, 96, 192);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:11px;font-weight:700;text-anchor:start;dominant-baseline:auto">normal</text>
+<text x="477" y="262" fill="#445566" font-size="9" font-family="monospace" style="fill:rgb(68, 85, 102);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:9px;font-weight:400;text-anchor:start;dominant-baseline:auto">for CSG</text>
+
+<!-- Right-side annotations -->
+<text x="644" y="98" fill="#334455" font-size="9" font-family="monospace" text-anchor="end" style="fill:rgb(51, 68, 85);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:9px;font-weight:400;text-anchor:end;dominant-baseline:auto">local</text>
+<text x="644" y="138" fill="#334455" font-size="9" font-family="monospace" text-anchor="end" style="fill:rgb(51, 68, 85);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:9px;font-weight:400;text-anchor:end;dominant-baseline:auto">camera</text>
+<text x="644" y="148" fill="#334455" font-size="9" font-family="monospace" text-anchor="end" style="fill:rgb(51, 68, 85);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:9px;font-weight:400;text-anchor:end;dominant-baseline:auto">space</text>
+<text x="644" y="178" fill="#334455" font-size="9" font-family="monospace" text-anchor="end" style="fill:rgb(51, 68, 85);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:9px;font-weight:400;text-anchor:end;dominant-baseline:auto">2D</text>
+<text x="644" y="188" fill="#334455" font-size="9" font-family="monospace" text-anchor="end" style="fill:rgb(51, 68, 85);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:9px;font-weight:400;text-anchor:end;dominant-baseline:auto">pixels</text>
+
+<!-- Pipeline arrow -->
+<line x1="654" y1="92" x2="654" y2="270" stroke="rgba(192,80,136,0.15)" stroke-width="1" mask="url(#imagine-text-gaps-eqff6y)" style="fill:rgb(0, 0, 0);stroke:rgba(192, 80, 136, 0.15);color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+<text x="651.09" y="90" fill="#445566" font-size="8" font-family="monospace" style="fill:rgb(68, 85, 102);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:8px;font-weight:400;text-anchor:start;dominant-baseline:auto">local</text>
+<text x="651.09" y="270" fill="#445566" font-size="8" font-family="monospace" style="fill:rgb(68, 85, 102);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:8px;font-weight:400;text-anchor:start;dominant-baseline:auto">screen</text>
+<polygon points="654,272 650,265 658,265" fill="rgba(192,80,136,0.3)" style="fill:rgba(192, 80, 136, 0.3);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+
+<!-- Summary -->
+<text x="510" y="310" text-anchor="middle" fill="#556677" font-size="10" font-family="monospace" style="fill:rgb(85, 102, 119);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:10px;font-weight:400;text-anchor:middle;dominant-baseline:auto">Tracks position across coordinate spaces</text>
+</svg>
--- /dev/null
+<svg viewBox="0 0 520 180" width="520" height="180" xmlns="http://www.w3.org/2000/svg">
+ <rect width="520" height="180" fill="#061018"/>
+
+ <!-- LEFT: Tearing -->
+ <text x="125" y="18" fill="#d04040" font-size="11" font-weight="700" font-family="monospace" text-anchor="middle">Without double-buffering</text>
+
+ <rect x="25" y="28" width="200" height="140" stroke="rgba(100,100,100,0.4)" stroke-width="1" fill="none" rx="3"/>
+ <text x="125" y="44" fill="#aaa" font-size="8" font-family="monospace" text-anchor="middle">display shows partial update</text>
+
+ <!-- Old frame top half -->
+ <rect x="45" y="52" width="160" height="45" fill="rgba(208,64,64,0.12)" stroke="rgba(208,64,64,0.4)" stroke-width="1"/>
+ <text x="125" y="79" fill="rgba(208,64,64,0.6)" font-size="9" font-family="monospace" text-anchor="middle">old frame</text>
+
+ <!-- Tear line -->
+ <line x1="45" y1="97" x2="205" y2="97" stroke="#d04040" stroke-width="2" stroke-dasharray="4,3"/>
+ <text x="228" y="100" fill="#d04040" font-size="8" font-family="monospace">← tear</text>
+
+ <!-- New frame bottom half -->
+ <rect x="45" y="97" width="160" height="55" fill="rgba(48,160,80,0.1)" stroke="rgba(48,160,80,0.4)" stroke-width="1"/>
+ <text x="125" y="130" fill="rgba(48,160,80,0.6)" font-size="9" font-family="monospace" text-anchor="middle">new frame</text>
+
+ <!-- RIGHT: Double-buffered -->
+ <text x="400" y="18" fill="#30a050" font-size="11" font-weight="700" font-family="monospace" text-anchor="middle">With double-buffering</text>
+
+ <!-- Back buffer -->
+ <rect x="295" y="35" width="90" height="130" fill="rgba(32,112,192,0.08)" stroke="rgba(32,112,192,0.5)" stroke-width="1.5" rx="2"/>
+ <text x="340" y="58" fill="#2070c0" font-size="9" font-family="monospace" text-anchor="middle">Back buffer</text>
+ <text x="340" y="72" fill="#aaa" font-size="7" font-family="monospace" text-anchor="middle">(draw here)</text>
+ <!-- Scribble lines to suggest "being drawn" -->
+ <line x1="310" y1="90" x2="365" y2="90" stroke="rgba(32,112,192,0.25)" stroke-width="1"/>
+ <line x1="310" y1="100" x2="355" y2="100" stroke="rgba(32,112,192,0.2)" stroke-width="1"/>
+ <line x1="310" y1="110" x2="345" y2="110" stroke="rgba(32,112,192,0.15)" stroke-width="1"/>
+
+ <!-- Swap arrow -->
+ <line x1="390" y1="100" x2="415" y2="100" stroke="#30a050" stroke-width="1.5"/>
+ <polygon points="415,96 423,100 415,104" fill="#30a050"/>
+ <text x="407" y="90" fill="#30a050" font-size="7" font-family="monospace" text-anchor="middle">swap</text>
+
+ <!-- Front buffer -->
+ <rect x="428" y="35" width="80" height="130" fill="rgba(48,160,80,0.1)" stroke="#30a050" stroke-width="1.5" rx="2"/>
+ <text x="468" y="58" fill="#30a050" font-size="9" font-family="monospace" text-anchor="middle">Front buffer</text>
+ <text x="468" y="72" fill="#aaa" font-size="7" font-family="monospace" text-anchor="middle">(displayed)</text>
+ <!-- Solid fill to suggest complete frame -->
+ <rect x="440" y="85" width="56" height="65" fill="rgba(48,160,80,0.08)" rx="1"/>
+ <text x="468" y="122" fill="rgba(48,160,80,0.5)" font-size="8" font-family="monospace" text-anchor="middle">complete</text>
+ <text x="468" y="133" fill="rgba(48,160,80,0.5)" font-size="8" font-family="monospace" text-anchor="middle">frame</text>
+</svg>
--- /dev/null
+<svg viewBox="0 0 400 200" width="400" height="200" xmlns="http://www.w3.org/2000/svg">
+ <rect width="400" height="200" fill="#061018"/>
+
+ <!-- Tile grid: 5 columns x 4 rows = 20 tiles over a 380x160 viewport -->
+ <g fill="#1a3a4a" stroke="#30a050" stroke-width="1">
+ <rect x="10" y="5" width="76" height="40"/>
+ <rect x="86" y="5" width="76" height="40"/>
+ <rect x="162" y="5" width="76" height="40"/>
+ <rect x="238" y="5" width="76" height="40"/>
+ <rect x="314" y="5" width="76" height="40"/>
+ <rect x="10" y="45" width="76" height="40"/>
+ <rect x="86" y="45" width="76" height="40"/>
+ <rect x="162" y="45" width="76" height="40"/>
+ <rect x="238" y="45" width="76" height="40"/>
+ <rect x="314" y="45" width="76" height="40"/>
+ <rect x="10" y="85" width="76" height="40"/>
+ <rect x="86" y="85" width="76" height="40"/>
+ <rect x="162" y="85" width="76" height="40"/>
+ <rect x="238" y="85" width="76" height="40"/>
+ <rect x="314" y="85" width="76" height="40"/>
+ <rect x="10" y="125" width="76" height="40"/>
+ <rect x="86" y="125" width="76" height="40"/>
+ <rect x="162" y="125" width="76" height="40"/>
+ <rect x="238" y="125" width="76" height="40"/>
+ <rect x="314" y="125" width="76" height="40"/>
+ </g>
+
+ <!-- A shape overlapping several tiles gets binned into each of them -->
+ <ellipse cx="200" cy="85" rx="90" ry="45" fill="rgba(255,102,0,0.25)" stroke="#FF6600" stroke-width="1.5"/>
+ <text x="200" y="89" fill="#FF6600" font-size="10" font-family="monospace" text-anchor="middle">one shape</text>
+
+ <text x="10" y="182" fill="#30a050" font-size="10" font-family="monospace">~10 tiles per thread; threads steal pending</text>
+ <text x="10" y="195" fill="#30a050" font-size="10" font-family="monospace">tiles — no fixed thread↔tile assignment</text>
+</svg>
--- /dev/null
+
+<svg viewBox="0 0 520 180" width="520" height="180" xmlns="http://www.w3.org/2000/svg">
+ <rect width="520" height="180" fill="#061018"/>
+ <!-- Far -->
+ <rect x="30" y="15" width="440" height="150" fill="rgba(48,160,80,0.06)" stroke="rgba(48,160,80,0.35)" stroke-width="1.5"/>
+ <text x="250" y="38" fill="rgba(48,160,80,0.7)" font-size="11" font-family="monospace" text-anchor="middle">Far (Z=500) — painted first</text>
+ <!-- Medium -->
+ <rect x="70" y="48" width="360" height="105" fill="rgba(32,112,192,0.10)" stroke="rgba(32,112,192,0.5)" stroke-width="1.5"/>
+ <text x="250" y="80" fill="rgba(32,112,192,0.85)" font-size="11" font-family="monospace" text-anchor="middle">Medium (Z=300) — painted second</text>
+ <!-- Near -->
+ <rect x="115" y="90" width="270" height="55" fill="rgba(200,80,140,0.18)" stroke="#c05088" stroke-width="2"/>
+ <text x="250" y="123" fill="#c05088" font-size="11" font-weight="700" font-family="monospace" text-anchor="middle">Near (Z=100) — painted last</text>
+</svg>
--- /dev/null
+<svg viewBox="0 0 620 80" width="620" height="80" xmlns="http://www.w3.org/2000/svg">
+ <defs>
+ <marker id="arrowhead" viewBox="0 0 10 10" refX="9" refY="5"
+ markerWidth="6" markerHeight="6" orient="auto">
+ <path d="M 0 0 L 10 5 L 0 10 z" fill="#30a050"/>
+ </marker>
+ </defs>
+ <rect width="620" height="80" fill="#061018"/>
+
+ <!-- Boxes -->
+ <rect x="8" y="25" width="70" height="30" rx="3" fill="rgba(48,160,80,0.15)" stroke="#30a050" stroke-width="1.5"/>
+ <text x="43" y="43" fill="#30a050" font-size="10" font-weight="700" font-family="monospace" text-anchor="middle">Shapes</text>
+
+ <rect x="96" y="25" width="90" height="30" rx="3" fill="rgba(32,112,192,0.15)" stroke="#2070c0" stroke-width="1.5"/>
+ <text x="141" y="43" fill="#2070c0" font-size="10" font-weight="700" font-family="monospace" text-anchor="middle">Transform</text>
+
+ <rect x="204" y="25" width="60" height="30" rx="3" fill="rgba(200,80,140,0.15)" stroke="#c05088" stroke-width="1.5"/>
+ <text x="234" y="43" fill="#c05088" font-size="10" font-weight="700" font-family="monospace" text-anchor="middle">Sort</text>
+
+ <rect x="282" y="25" width="60" height="30" rx="3" fill="rgba(255,170,0,0.15)" stroke="#dd9900" stroke-width="1.5"/>
+ <text x="312" y="43" fill="#dd9900" font-size="10" font-weight="700" font-family="monospace" text-anchor="middle">Bin</text>
+
+ <rect x="360" y="25" width="70" height="30" rx="3" fill="rgba(255,102,0,0.15)" stroke="#FF6600" stroke-width="1.5"/>
+ <text x="395" y="43" fill="#FF6600" font-size="10" font-weight="700" font-family="monospace" text-anchor="middle">Paint</text>
+
+ <rect x="448" y="25" width="80" height="30" rx="3" fill="rgba(57,255,20,0.15)" stroke="#39FF14" stroke-width="1.5"/>
+ <text x="488" y="43" fill="#39FF14" font-size="10" font-weight="700" font-family="monospace" text-anchor="middle">Present</text>
+
+ <rect x="546" y="25" width="66" height="30" rx="3" fill="rgba(100,100,100,0.2)" stroke="#aaa" stroke-width="1.5"/>
+ <text x="579" y="43" fill="#aaa" font-size="10" font-weight="700" font-family="monospace" text-anchor="middle">Screen</text>
+
+ <!-- Arrows -->
+ <line x1="78" y1="40" x2="92" y2="40" stroke="#30a050" stroke-width="1.5" marker-end="url(#arrowhead)"/>
+ <line x1="186" y1="40" x2="200" y2="40" stroke="#2070c0" stroke-width="1.5" marker-end="url(#arrowhead)"/>
+ <line x1="264" y1="40" x2="278" y2="40" stroke="#c05088" stroke-width="1.5" marker-end="url(#arrowhead)"/>
+ <line x1="342" y1="40" x2="356" y2="40" stroke="#dd9900" stroke-width="1.5" marker-end="url(#arrowhead)"/>
+ <line x1="430" y1="40" x2="444" y2="40" stroke="#FF6600" stroke-width="1.5" marker-end="url(#arrowhead)"/>
+ <line x1="528" y1="40" x2="542" y2="40" stroke="#39FF14" stroke-width="1.5" marker-end="url(#arrowhead)"/>
+
+ <!-- Labels below -->
+ <text x="43" y="67" fill="#666" font-size="8" font-family="monospace" text-anchor="middle">3D vertices</text>
+ <text x="141" y="67" fill="#666" font-size="8" font-family="monospace" text-anchor="middle">world→screen</text>
+ <text x="234" y="67" fill="#666" font-size="8" font-family="monospace" text-anchor="middle">back-to-front</text>
+ <text x="312" y="67" fill="#666" font-size="8" font-family="monospace" text-anchor="middle">per tile</text>
+ <text x="395" y="67" fill="#666" font-size="8" font-family="monospace" text-anchor="middle">tile grid</text>
+ <text x="488" y="67" fill="#666" font-size="8" font-family="monospace" text-anchor="middle">own thread</text>
+</svg>
--- /dev/null
+#+SETUPFILE: ~/.emacs.d/org-styles/html/darksun.theme
+#+TITLE: Rendering Loop - Aukio 3D
+#+LANGUAGE: en
+#+LATEX_HEADER: \usepackage[margin=1.0in]{geometry}
+#+LATEX_HEADER: \usepackage{parskip}
+#+LATEX_HEADER: \usepackage[none]{hyphenat}
+
+#+OPTIONS: H:20 num:20
+#+OPTIONS: author:nil
+
+#+HTML_HEAD: <link rel="stylesheet" href="../style.css"/>
+
+[[file:../index.html#outline-container-understanding-3d-engine][<- Back to index]]
+
+* Rendering loop
+:PROPERTIES:
+:CUSTOM_ID: rendering-loop
+:ID: a1b2c3d4-e5f6-7890-abcd-ef1234567890
+:END:
+
+The rendering loop is the heart of the engine, continuously generating
+frames on a dedicated background thread. It orchestrates the entire
+rendering pipeline from 3D world space to pixels on screen.
+
+** What is a render loop?
+:PROPERTIES:
+:CUSTOM_ID: what-is-a-render-loop
+:END:
+
+A *render loop* is a continuous process that generates visual frames
+from 3D data. Think of it like a movie camera: each "frame" captures
+the current state of the 3D world and converts it into a 2D image that
+can be displayed on screen.
+
+The process transforms shapes through multiple coordinate systems:
+
+#+INCLUDE: "Render pipeline.svg" export html
+
+Each step has a specific purpose:
+
+| Step | Input | Output | Purpose |
+|-----------+-------+--------+---------|
+| Shapes | 3D [[file:../index.org::#vertex][vertices]], [[file:../index.org::#mesh][meshes]] | Scene data | Objects waiting to be drawn |
+| Transform | World coordinates | Screen coordinates | Convert 3D positions to where they appear on screen (see [[file:../index.org::#coordinate-system][coordinate system]]); cull shapes outside the view frustum. Parallel: heavy subtrees fork onto the worker pool |
+| Sort | Unordered shapes | Ordered by depth | Ensure correct visibility (far objects painted first). Parallel merge sort for large scenes |
+| Bin | Sorted shapes | Per-tile shape lists | Each paint tile iterates only shapes that can touch it. Parallel over the worker pool |
+| Paint | Per-tile shape lists | Pixels in buffer | Tiles split the screen into independent work units so clearing and rasterization run in parallel across CPU cores |
+| Present | Pixel buffer | Screen image | Hand the completed frame to a dedicated thread that copies it to the display |
+
+This pipeline runs repeatedly, targeting 60 frames per second by
+default. Even if nothing moves, the loop continues running—but the
+engine [[#frame-listeners][skips unnecessary work]] when the scene is static.
+
+The steps above describe one frame *logically*, in the order data flows
+through it. In execution the engine is a software pipeline: transform
+of the next frame already runs while the previous frame is still being
+painted, and presentation happens on its own thread. See
+[[#software-pipeline][Software pipeline]].
+
+** Main loop structure
+:PROPERTIES:
+:CUSTOM_ID: main-loop-structure
+:END:
+
+The engine runs two dedicated daemon threads:
+
+- =e3d-render= — produces frames. It runs continuously:
+
+#+BEGIN_SRC java
+while (renderThreadRunning) {
+ ensureThatViewIsUpToDate(); // Produce one frame (or skip)
+ maintainTargetFps(); // Sleep if ahead of schedule
+}
+#+END_SRC
+
+- =e3d-present= — presents frames. It takes completed frames from a
+ mailbox and performs all display-path work (the multi-megabyte
+ =drawImage=, =BufferStrategy.show()= and the X server round-trip), so
+ the render thread never blocks on the display.
+
+Both threads are daemons, so they stop automatically when the JVM
+exits. You can stop them explicitly with [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/gui/ViewPanel.html#stop()][ViewPanel.stop()]].
+
+** Frame rate control
+:PROPERTIES:
+:CUSTOM_ID: frame-rate-control
+:END:
+
+The engine supports two modes:
+
+- *Target FPS mode*: Set with [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/gui/ViewPanel.html#setFrameRate(int)][setFrameRate(int)]].
+ The engine tries to maintain the target rate by sleeping between frames.
+
+ - *When rendering is slower than target*: No sleeping occurs. The engine
+ runs at maximum hardware speed. Missed frames are skipped, not
+ rendered later — the timing simply resets to current time.
+
+ - *When rendering is faster than target*: The thread sleeps to limit FPS
+ to the target rate, avoiding unnecessary CPU usage.
+
+ For example, with a 60 FPS target:
+ - If a complex scene takes 30ms per frame, you get ~33 FPS (hardware limit)
+ - If the scene later simplifies to 10ms per frame, you get exactly
+ 60 FPS (throttled by sleeping)
+
+- *Unlimited mode*: Set =setFrameRate(0)= or negative. No sleeping —
+ renders as fast as possible, and frames are produced even when the
+ scene reports no changes, so the measured rate reflects maximum
+ achievable throughput. Useful for benchmarking.
+
+*Production vs presentation.* These are measured separately:
+
+- *Production rate* (=getMeasuredFPS()=) counts frames the pipeline
+ completes per second. This is the benchmark number.
+- *Presentation rate* is how fast frames actually reach the screen. In
+ capped-FPS mode the present thread is paced to 60 blits per second
+ (override with =-Daukio3d.presentRate=N=); the cap exists because the
+ X server also dispatches input, and flooding it with blits causes
+ desktop-wide mouse/keyboard jitter. When production outruns
+ presentation, stale frames are dropped from the mailbox instead of
+ piling up latency. In unlimited (benchmark) mode presentation pacing
+ is disabled entirely, so it cannot throttle production.
+
+* Software pipeline
+:PROPERTIES:
+:CUSTOM_ID: software-pipeline
+:END:
+
+The phases below are described per frame, but consecutive frames
+*overlap*. The engine triple-buffers everything a frame writes:
+
+- 3 framebuffers (each with its own =RenderingContext=)
+- 3 projection buffer slots (per-vertex screen state)
+- 3 render aggregators (transform output, sort/bin state)
+
+A render pass P (one per frame, or one per eye in stereo) transforms
+into slot P mod 3, so it only conflicts with the paint of pass P-3.
+Before each transform the render thread *flushes* completed paint
+passes (mouse hits, frame deposit) and blocks only if paint P-3 is
+still running — which steady-state worker throughput prevents. Workers
+finishing one pass's tiles flow straight into the next pass's queued
+tiles with no idle gap.
+
+Completed frames go to a *presentation mailbox* that keeps only the
+newest frame: if the display path is slower than production, stale
+frames are dropped (and their buffers released) instead of
+accumulating latency — swapchain "mailbox mode".
+
+A per-buffer *present gate* guarantees painting frame F+3 never
+overwrites a buffer the present thread is still blitting frame F from.
+
+The goal of all this overlap is throughput: keep every CPU core busy,
+all the time. No phase waits for another phase of the same frame when
+it could already be working on the next one. The Developer Tools
+thread-activity timeline shows it working — all 18 worker rows packed
+solid with paint, bin and sort tasks from up to three frames at once,
+while the render thread (top row) and present thread tick along above
+them:
+
+#+attr_html: :class responsive-img
+[[file:CPU scheduling.png]]
+
+The pipeline can be disabled with =-Daukio3d.pipeline=false=, restoring
+strictly sequential phase order (each paint pass is awaited
+immediately). This is a kill switch for benchmarking and regression
+hunting.
+
+* Rendering phases
+:PROPERTIES:
+:CUSTOM_ID: rendering-phases
+:END:
+
+Each frame goes through 6 phases. Phases 2–4 run inside an
+asynchronous continuation on the shared worker pool, and phases of
+consecutive frames overlap as described in [[#software-pipeline][Software pipeline]].
+
+** Phase 1: Transform shapes
+:PROPERTIES:
+:CUSTOM_ID: phase-1-transform-shapes
+:END:
+
+All shapes are transformed from world space to screen space:
+
+1. Build camera-relative transform (inverse of camera position/rotation)
+2. Update the view frustum from camera state and viewport dimensions
+3. Walk the scene tree:
+ - Cull composite shapes whose bounding box misses the frustum
+ - Apply camera transform
+ - Project 3D → 2D (perspective projection)
+ - Calculate depth for sorting
+ - Queue for rendering
+
+*What is coordinate transformation?*
+
+Every shape exists in "world space" — its own position in the 3D world.
+To render it, we must convert to "screen space" — where it appears on
+your monitor. This involves:
+
+- *Translation*: Move coordinates relative to camera position
+- *Rotation*: Rotate coordinates based on camera orientation
+- *Projection*: Convert 3D (x, y, z) to 2D (x, y) screen pixels
+
+Objects further away appear smaller (perspective). The [[file:../index.org::#coordinate-system][coordinate system]]
+uses Y-down to match screen conventions, making projection straightforward.
+
+The transform is *parallel and non-blocking*: composites with enough
+children fork their render lists into chunk tasks on the shared worker
+pool (at any nesting level), and the render thread returns without
+waiting. The chunk tasks are drained and merged on a worker thread
+inside the paint continuation, while the render thread is already
+walking the next pass.
+
+*Frustum culling* happens here: composites test their bounding box
+against the frustum and skip invisible subtrees entirely, saving both
+transform and paint work. Per-frame culling statistics are collected
+for the developer tools panel.
+
+** Phase 2: Sort shapes by depth
+:PROPERTIES:
+:CUSTOM_ID: phase-2-sort-shapes
+:END:
+
+Shapes are sorted by depth in descending order (farthest first), with
+the shape id as a deterministic tiebreaker:
+
+#+BEGIN_SRC java
+// ShapesZIndexComparator: descending Z, ties broken by shape id
+if (z1 < z2) return 1; // z1 is nearer -> sort after z2
+else if (z1 > z2) return -1; // z1 is farther -> sort before z2
+return Integer.compare(o1.shapeId, o2.shapeId);
+#+END_SRC
+
+Above 8192 queued shapes the sort runs as an instrumented parallel
+merge sort on the shared worker pool; below that it is single-threaded.
+
+*Why sort back-to-front?*
+
+This implements the *painter's algorithm* — like painting a landscape:
+first paint the sky (farthest), then mountains, then trees, then the
+foreground. Each layer covers what's behind it.
+
+#+INCLUDE: "Painter's algorithm.svg" export html
+
+Without sorting, nearby objects might be painted first and then covered
+by distant ones, causing visual errors. This is especially important for
+*transparent objects* — you need to see through the near ones to what's
+behind.
+
+The Z value represents distance from the camera after transformation.
+Larger values = further away. The id tiebreaker keeps the order
+deterministic frame-to-frame, which tiled rendering relies on: every
+tile paints its shapes in the same global (Z, id) order.
+
+** Phase 3: Bin shapes into tiles
+:PROPERTIES:
+:CUSTOM_ID: phase-3-bin-shapes-into-tiles
+:END:
+
+The sorted queue is binned per paint tile by screen-space overlap:
+each tile's bin lists only the shapes whose vertex bounds (plus a
+paint margin) can touch that tile. A shape overlapping several tiles
+is added to each of their bins.
+
+This means a paint thread iterates a short local list instead of the
+whole scene, and it is what makes the tile grid scale: refining the
+grid shrinks each bin instead of just subdividing the clearing work.
+
+Binning is parallelized over the shared worker pool.
+
+** Phase 4: Clear and paint tiles (multi-threaded)
+:PROPERTIES:
+:CUSTOM_ID: phase-4-clear-paint-tiles
+:END:
+
+The viewport is divided into a grid of rectangular *tiles* — roughly
+10 tiles per render thread, split into near-squares (square tiles
+minimize boundary crossings, i.e. how many tiles each shape overlaps).
+These are *not* horizontal bands: each tile has both X and Y bounds.
+
+#+INCLUDE: "Paint tiles.svg" export html
+
+Painting is work-stolen, not pre-assigned. All tile tasks go onto a
+shared =ForkJoinPool= (sized to 75% of CPU threads by default, at most
+cores − 1, so one thread stays free for the rest of the system;
+changeable at runtime via =setNumRenderThreads(int)=). A worker that
+finishes a cheap tile immediately pulls the next queued task — another
+tile (of this or an adjacent frame's pass), a transform chunk, a sort
+piece — so cores never idle behind a busy thread.
+
+Each tile task:
+
+1. *Clear tile*: fill its rectangle with background color
+2. *Paint shapes*: rasterize the tile's bin, back-to-front, clipping
+ at tile bounds
+
+Both operations happen within the same task, so clearing always
+completes before painting on that tile. Parallel clearing across
+disjoint tiles maximizes memory bandwidth utilization.
+
+Each tile renders through a =SegmentRenderingContext= — a view of the
+frame context carrying the tile's X/Y bounds and a =Graphics2D=
+pre-clipped to the tile rectangle for thread-safe text and
+anti-aliased drawing. (The class name predates the tile grid; a
+"segment" is now a tile.) Mouse hit detection happens during painting,
+before clipping.
+
+A =CountDownLatch= tracks completion of all the pass's tiles — but the
+render thread does *not* wait for it here. The latch is awaited one
+pass later, during the flush (see [[#phase-5-flush-completed-passes][Phase 5]]).
+
+** Phase 5: Flush completed passes
+:PROPERTIES:
+:CUSTOM_ID: phase-5-flush-completed-passes
+:END:
+
+Before each new transform, the render thread flushes paint passes that
+have completed. For each flushed pass:
+
+1. Await its tile latch (blocks only when correctness demands it —
+ transform of pass P may not start before paint of pass P-3 finished)
+2. *Combine mouse results*: during painting, each tile tracked which
+ shape is under the mouse cursor. Since all tiles paint the same
+ back-to-front order, they should all report the same hit; the first
+ non-null result wins:
+
+#+BEGIN_SRC java
+for (SegmentRenderingContext ctx : segmentContexts) {
+ if (ctx.getSegmentMouseHit() != null) {
+ context.setCurrentObjectUnderMouseCursor(ctx.getSegmentMouseHit());
+ return;
+ }
+}
+#+END_SRC
+
+ In stereo mode this only runs for the eye whose viewport actually
+ contains the cursor — each eye sees a different camera position, so
+ combining for the wrong eye would overwrite a valid hit with null.
+3. If this pass completed a frame, deposit the frame into the
+ presentation mailbox (see [[#software-pipeline][Software pipeline]]). The render
+ thread never blocks on the display.
+
+Passes that finished painting are flushed without any blocking, so
+completed frames reach the mailbox as early as possible.
+
+** Phase 6: Present frame
+:PROPERTIES:
+:CUSTOM_ID: phase-6-present-frame
+:END:
+
+The =e3d-present= thread takes the newest mailbox frame (dropping any
+unshown older frame) and copies its =BufferedImage= to the screen using
+[[https://cr.openjdk.org/~iris/se/17/latestSpec/api/java.desktop/java/awt/image/BufferStrategy.html][BufferStrategy]] for tear-free page-flipping:
+
+#+BEGIN_SRC java
+do {
+ Graphics2D g = bufferStrategy.getDrawGraphics();
+ g.drawImage(context.bufferedImage, 0, 0, null);
+ g.dispose();
+} while (bufferStrategy.contentsRestored());
+
+// framebuffer released for reuse here
+bufferStrategy.show();
+Toolkit.getDefaultToolkit().sync();
+#+END_SRC
+
+The frame's buffer is released for reuse right after the =drawImage=
+loop — =show()= and =sync()= touch only the BufferStrategy's own back
+buffer and the X connection, and at high resolutions they cost more
+than the draw itself, so the next frame's painters don't wait for them.
+
+*What is double-buffering?*
+
+Without double-buffering, the screen updates while pixels are being
+written. This causes *screen tearing* — visible horizontal splits where
+the top of the frame shows old content while the bottom shows new.
+
+#+INCLUDE: "Double buffering.svg" export html
+
+Double-buffering uses two pixel buffers:
+- *Back buffer*: Where rendering happens (offscreen, invisible)
+- *Front buffer*: What's currently displayed on screen
+
+When rendering completes, the buffers *swap* in one atomic operation.
+The viewer always sees complete frames, never partial updates.
+
+The =do-while= loop handles the case where the OS recreates the back
+buffer (common during window resizing). Since our offscreen
+=BufferedImage= still has the correct pixels, we only need to re-blit,
+not re-render.
+
+* Frame listeners and smart repaint skipping
+:PROPERTIES:
+:CUSTOM_ID: frame-listeners
+:ID: e360a877-cca6-4cba-a9a4-ea40b0f1a183
+:END:
+
+A *FrameListener* is a callback that runs custom logic before each potential
+frame. Think of it as your "per-frame hook" — the engine calls all registered
+listeners, giving them a chance to update animations, physics, or game logic.
+
+** Registering a frame listener
+:PROPERTIES:
+:CUSTOM_ID: registering-frame-listener
+:END:
+
+Use [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/gui/ViewPanel.html#addFrameListener(eu.svjatoslav.aukio.e3d.gui.FrameListener)][addFrameListener()]] to register your callback:
+
+#+BEGIN_SRC java
+// This is how you register a frame listener
+viewPanel.addFrameListener((panel, deltaMs) -> {
+ // Example: simple animation listener
+ double rotationSpeed = 1.0; // radians per second
+ shape.rotate(rotationSpeed * deltaMs / 1000.0); // Framerate-independent rotation
+ return true; // Request repaint (shape moved)
+});
+#+END_SRC
+
+The listener receives two parameters:
+- =panel=: The ViewPanel that's rendering
+- =deltaMs=: Milliseconds since last frame (for framerate-independent animation)
+
+The return value controls whether the frame gets rendered:
+- =true=: "Something changed — repaint the screen"
+- =false=: "Nothing changed — can skip this frame"
+
+** Frame skipping optimization
+:PROPERTIES:
+:CUSTOM_ID: frame-skipping-optimization
+:END:
+
+The engine avoids unnecessary rendering. A frame is skipped when:
+- *All listeners return false* (nothing changed in your scene)
+- *Camera did not move* (built-in Camera listener returns false once
+ the camera comes to rest)
+- *No resize or repaint requests*
+
+This means a static scene with no animations consumes almost zero CPU.
+The render thread keeps running (checking for changes), but actual pixel
+rendering is skipped entirely. Skipped frames still flush any pending
+paint passes from earlier frames, so in-flight frames always reach the
+screen.
+
+Two exceptions force a frame regardless of listeners:
+- *Unlimited (benchmark) mode* (=targetFPS <= 0=) renders continuously,
+ so the measured rate reflects maximum throughput
+- An explicit repaint request (resize, stereo toggle,
+ =repaintDuringNextViewUpdate()=, etc.)
+
+#+BEGIN_SRC java
+// Example: listener that only requests repaint when needed
+viewPanel.addFrameListener((panel, deltaMs) -> {
+ if (gameState.hasUpdates()) {
+ gameState.processUpdates();
+ return true; // Only repaint when game state actually changed
+ }
+ return false; // Skip frame — nothing to update
+});
+#+END_SRC
+
+** Built-in listeners
+:PROPERTIES:
+:CUSTOM_ID: built-in-listeners
+:END:
+
+The engine registers these listeners by default:
+- [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/gui/Camera.html][Camera]] — applies movement velocity and friction each frame, and
+ returns true when the camera actually moved (more than a small
+ threshold), i.e. while the user is actively navigating
+- [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/gui/humaninput/InputManager.html][InputManager]] — processes mouse/keyboard events
+
+When the camera stops moving and you release all keys, the Camera listener
+returns false. If your custom listeners also return false, the frame is
+skipped until something changes.
+
+* Rendering context
+:PROPERTIES:
+:CUSTOM_ID: rendering-context
+:END:
+
+The [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/gui/RenderingContext.html][RenderingContext]] holds all state for rendering into one framebuffer:
+the pixel buffer, projection parameters, and per-frame bookkeeping.
+
+| Field | Purpose |
+|-------+---------|
+| =pixels[]= | Raw pixel buffer (int[] in RGB format) |
+| =bufferedImage= | Java2D wrapper around pixels |
+| =graphics= | Graphics2D for text, lines, shapes |
+| =width=, =height= | Full framebuffer dimensions |
+| =centerCoordinate= | Screen center of the active viewport (for projection) |
+| =projectionScale= | Perspective scale factor, derived from viewport width. Mutable: each stereo eye sets its own |
+| =renderMinX=, =renderMaxX= | X bounds of the active viewport or tile |
+| =renderMinY=, =renderMaxY= | Y bounds (full height on the frame context, tile bounds on segment views) |
+| =stereoEye=, =stereoViewportWidth=, =stereoViewportOffsetX= | Which eye this pass renders and where its viewport sits in the buffer |
+| =tilesX=, =tilesY=, =viewportCount=, =numRenderSegments= | Tile grid geometry (segments = tilesX × tilesY × viewports) |
+| =frustum= | View frustum for culling, rebuilt each pass from camera state |
+| =frameNumber= | Per-context frame counter |
+| =transformCycleId= | Globally unique transform-cycle id, safe key for per-cycle memoization |
+| =vertexSlot= | Projection buffer slot (0–2) this pass transforms into |
+
+** Triple-buffered frame contexts
+:PROPERTIES:
+:CUSTOM_ID: triple-buffered-frame-contexts
+:END:
+
+The engine keeps /three/ frame contexts, cycled by frame parity. While
+frame N is still being painted from one buffer, frame N+1 already
+transforms into the next — paint threads never idle waiting for the
+transform phase, and vice versa. A per-buffer *present gate* prevents
+painting frame F+3 into a buffer the present thread is still blitting
+frame F from.
+
+All three contexts are recreated together when the window is resized,
+when the tile grid changes (render thread count), or when stereo mode
+is toggled. Otherwise they are reused — =prepareForNewFrameRendering()=
+just resets per-frame state like mouse tracking.
+
+** Per-pass copies
+:PROPERTIES:
+:CUSTOM_ID: per-pass-copies
+:END:
+
+Each render pass (one per eye in stereo) works on a private /copy/ of
+the frame context. The copy shares the pixel buffer, graphics and
+services, but owns the projection fields (center, scale, viewport,
+vertex slot), so the next pass's setup cannot disturb a pass whose
+transform or paint is still in flight.
+
+Consequence for engine code: per-frame mutable state must be allocated
+eagerly on the frame context. Anything created lazily inside a pass
+lands on the throwaway copy and is lost.
+
+** Tile segment views
+:PROPERTIES:
+:CUSTOM_ID: tile-segment-views
+:END:
+
+Each paint tile gets a [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/gui/SegmentRenderingContext.html][SegmentRenderingContext]],
+a view that shares the framebuffer with its parent but carries its own
+X/Y tile bounds and a pre-clipped =Graphics2D= for thread-safe text and
+shape drawing. Mouse hits are tracked per tile and combined after all
+tiles finish painting.
--- /dev/null
+<svg viewBox="0 0 640 430" width="640" height="430" xmlns="http://www.w3.org/2000/svg">
+ <defs>
+ <filter id="glow">
+ <feGaussianBlur stdDeviation="2" result="blur"/>
+ <feMerge>
+ <feMergeNode in="blur"/>
+ <feMergeNode in="SourceGraphic"/>
+ </feMerge>
+ </filter>
+ </defs>
+
+ <rect width="640" height="430" fill="#061018"/>
+
+ <text x="320" y="32" fill="#40b0d0" font-size="16" font-family="monospace" text-anchor="middle" filter="url(#glow)">Why a distance field, not a bitmap</text>
+ <text x="320" y="50" fill="#999" font-size="10" font-family="monospace" text-anchor="middle">one glyph edge, magnified 8x - stored coverage vs re-derived coverage</text>
+
+ <!-- LEFT: stored bitmap coverage -->
+ <text x="160" y="86" fill="#FF8833" font-size="12" font-family="monospace" text-anchor="middle" filter="url(#glow)">BITMAP coverage</text>
+ <text x="160" y="101" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">what you store is what you get</text>
+
+ <!-- blocky stair edge -->
+ <g stroke="none">
+ <rect x="60" y="120" width="40" height="40" fill="#39FF14" opacity="0.85"/>
+ <rect x="100" y="120" width="40" height="40" fill="#39FF14" opacity="0.5"/>
+ <rect x="60" y="160" width="40" height="40" fill="#39FF14" opacity="0.85"/>
+ <rect x="100" y="160" width="40" height="40" fill="#39FF14" opacity="0.85"/>
+ <rect x="140" y="160" width="40" height="40" fill="#39FF14" opacity="0.4"/>
+ <rect x="60" y="200" width="40" height="40" fill="#39FF14" opacity="0.85"/>
+ <rect x="100" y="200" width="40" height="40" fill="#39FF14" opacity="0.85"/>
+ <rect x="140" y="200" width="40" height="40" fill="#39FF14" opacity="0.85"/>
+ <rect x="180" y="200" width="40" height="40" fill="#39FF14" opacity="0.3"/>
+ <rect x="60" y="240" width="40" height="40" fill="#39FF14" opacity="0.85"/>
+ <rect x="100" y="240" width="40" height="40" fill="#39FF14" opacity="0.85"/>
+ <rect x="140" y="240" width="40" height="40" fill="#39FF14" opacity="0.85"/>
+ <rect x="180" y="240" width="40" height="40" fill="#39FF14" opacity="0.7"/>
+ </g>
+ <g stroke="#1a3a4a" stroke-width="1" fill="none">
+ <rect x="60" y="120" width="200" height="160"/>
+ <line x1="100" y1="120" x2="100" y2="280"/>
+ <line x1="140" y1="120" x2="140" y2="280"/>
+ <line x1="180" y1="120" x2="180" y2="280"/>
+ <line x1="220" y1="120" x2="220" y2="280"/>
+ <line x1="60" y1="160" x2="260" y2="160"/>
+ <line x1="60" y1="200" x2="260" y2="200"/>
+ <line x1="60" y1="240" x2="260" y2="240"/>
+ </g>
+ <text x="160" y="305" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">texel grid IS the resolution limit:</text>
+ <text x="160" y="318" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">edges stair-step, curves become blocks</text>
+
+ <!-- RIGHT: distance field -->
+ <text x="480" y="86" fill="#39FF14" font-size="12" font-family="monospace" text-anchor="middle" filter="url(#glow)">SDF: distance to edge</text>
+ <text x="480" y="101" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">a smooth field - the edge is re-derived per pixel</text>
+
+ <!-- smooth edge line through a gradient field -->
+ <defs>
+ <linearGradient id="sdfGrad" x1="0" y1="0" x2="1" y2="1">
+ <stop offset="0" stop-color="#39FF14" stop-opacity="0.85"/>
+ <stop offset="0.42" stop-color="#39FF14" stop-opacity="0.55"/>
+ <stop offset="0.55" stop-color="#39FF14" stop-opacity="0.25"/>
+ <stop offset="0.7" stop-color="#39FF14" stop-opacity="0.06"/>
+ <stop offset="1" stop-color="#39FF14" stop-opacity="0"/>
+ </linearGradient>
+ </defs>
+ <rect x="380" y="120" width="200" height="160" fill="url(#sdfGrad)"/>
+ <rect x="380" y="120" width="200" height="160" fill="none" stroke="#1a3a4a" stroke-width="1"/>
+ <!-- the re-derived edge: crisp at any zoom -->
+ <line x1="420" y1="280" x2="530" y2="120" stroke="#40b0d0" stroke-width="2" filter="url(#glow)"/>
+ <text x="500" y="270" fill="#40b0d0" font-size="9" font-family="monospace">edge recovered at</text>
+ <text x="500" y="282" fill="#40b0d0" font-size="9" font-family="monospace">display resolution</text>
+
+ <!-- distance annotations -->
+ <text x="410" y="150" fill="#999" font-size="9" font-family="monospace">d < 0: inside ink</text>
+ <text x="520" y="140" fill="#999" font-size="9" font-family="monospace">d > 0: outside</text>
+ <text x="455" y="205" fill="#40b0d0" font-size="9" font-family="monospace" transform="rotate(-52 455 205)">d = 0: the edge</text>
+
+ <!-- bottom takeaway -->
+ <rect x="40" y="340" width="560" height="64" rx="6" fill="rgba(64,176,208,0.06)" stroke="#40b0d0" stroke-width="1"/>
+ <text x="320" y="364" fill="#40b0d0" font-size="11" font-family="monospace" text-anchor="middle" filter="url(#glow)">coverage = (127.5 - d) * aaK + 128</text>
+ <text x="320" y="382" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">aaK scales the gradient window to the pixel footprint - the same 16x32 texel field</text>
+ <text x="320" y="395" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">serves a 4-pixel label and a full-screen billboard</text>
+</svg>
--- /dev/null
+<svg viewBox="0 0 640 470" width="640" height="470" xmlns="http://www.w3.org/2000/svg">
+ <defs>
+ <filter id="glow">
+ <feGaussianBlur stdDeviation="2" result="blur"/>
+ <feMerge>
+ <feMergeNode in="blur"/>
+ <feMergeNode in="SourceGraphic"/>
+ </feMerge>
+ </filter>
+ <marker id="arr" viewBox="0 0 10 10" refX="9" refY="5" markerWidth="7" markerHeight="7" orient="auto-start-reverse">
+ <path d="M 0 0 L 10 5 L 0 10 z" fill="#40b0d0"/>
+ </marker>
+ </defs>
+
+ <rect width="640" height="470" fill="#061018"/>
+
+ <text x="320" y="30" fill="#40b0d0" font-size="16" font-family="monospace" text-anchor="middle" filter="url(#glow)">Glyph field generation (SdfGlyphCache)</text>
+ <text x="320" y="48" fill="#999" font-size="10" font-family="monospace" text-anchor="middle">once per character, then cached - stamping is a block copy</text>
+
+ <!-- step 1: hi-res rasterize -->
+ <rect x="40" y="70" width="170" height="84" rx="6" fill="rgba(57,255,20,0.07)" stroke="#39FF14" stroke-width="1.5"/>
+ <text x="125" y="90" fill="#39FF14" font-size="11" font-family="monospace" text-anchor="middle">1. rasterize glyph</text>
+ <text x="125" y="106" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">Liberation Mono Bold, AA on</text>
+ <text x="125" y="119" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">64x128 px (4x supersample)</text>
+ <text x="125" y="132" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">font auto-sized to fit cell</text>
+ <text x="125" y="148" fill="#c05088" font-size="9" font-family="monospace" text-anchor="middle">advance 0.6em (Courier-compat)</text>
+
+ <line x1="210" y1="112" x2="240" y2="112" stroke="#40b0d0" stroke-width="1.5" marker-end="url(#arr)"/>
+
+ <!-- step 2: EDT -->
+ <rect x="245" y="70" width="170" height="84" rx="6" fill="rgba(64,176,208,0.07)" stroke="#40b0d0" stroke-width="1.5"/>
+ <text x="330" y="90" fill="#40b0d0" font-size="11" font-family="monospace" text-anchor="middle">2. distance transform</text>
+ <text x="330" y="106" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">exact Euclidean EDT</text>
+ <text x="330" y="119" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">(Felzenszwalb-Huttenlocher,</text>
+ <text x="330" y="132" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">two separable 1-D passes)</text>
+ <text x="330" y="148" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">dOut to ink, dIn to background</text>
+
+ <line x1="415" y1="112" x2="445" y2="112" stroke="#40b0d0" stroke-width="1.5" marker-end="url(#arr)"/>
+
+ <!-- step 3: signed + clamp + downsample -->
+ <rect x="450" y="70" width="160" height="96" rx="6" fill="rgba(255,136,51,0.07)" stroke="#FF8833" stroke-width="1.5"/>
+ <text x="530" y="88" fill="#FF8833" font-size="11" font-family="monospace" text-anchor="middle">3. sign, clamp, average</text>
+ <text x="530" y="104" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">signed = dOut - dIn</text>
+ <text x="530" y="117" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">clamp to +/- 2 texels spread</text>
+ <text x="530" y="130" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">average FIELD down to 16x32</text>
+ <text x="530" y="148" fill="#c05088" font-size="9" font-family="monospace" text-anchor="middle">(averaging the field, not coverage,</text>
+ <text x="530" y="160" fill="#c05088" font-size="9" font-family="monospace" text-anchor="middle">preserves the edge position)</text>
+
+ <!-- down to mask encoding -->
+ <line x1="530" y1="180" x2="530" y2="196" stroke="#40b0d0" stroke-width="1.5" marker-end="url(#arr)"/>
+
+ <!-- encoding bar -->
+ <rect x="120" y="200" width="420" height="54" rx="6" fill="rgba(192,80,136,0.07)" stroke="#c05088" stroke-width="1.5"/>
+ <text x="330" y="220" fill="#c05088" font-size="11" font-family="monospace" text-anchor="middle">mask encoding (per texel, 0..255)</text>
+ <text x="330" y="236" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">0 = deep inside ink 127.5 = the edge 255 = far outside</text>
+
+ <!-- gradient strip -->
+ <defs>
+ <linearGradient id="maskBar" x1="0" y1="0" x2="1" y2="0">
+ <stop offset="0" stop-color="#000000"/>
+ <stop offset="0.5" stop-color="#808080"/>
+ <stop offset="1" stop-color="#ffffff"/>
+ </linearGradient>
+ </defs>
+ <rect x="170" y="242" width="320" height="8" fill="url(#maskBar)"/>
+
+ <!-- consumers -->
+ <line x1="240" y1="254" x2="240" y2="286" stroke="#40b0d0" stroke-width="1.5" marker-end="url(#arr)"/>
+ <line x1="430" y1="254" x2="430" y2="286" stroke="#40b0d0" stroke-width="1.5" marker-end="url(#arr)"/>
+
+ <rect x="120" y="290" width="240" height="66" rx="6" fill="rgba(57,255,20,0.06)" stroke="#39FF14" stroke-width="1"/>
+ <text x="240" y="310" fill="#39FF14" font-size="11" font-family="monospace" text-anchor="middle">TextCanvas.putChar</text>
+ <text x="240" y="326" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">stamps the cached 16x32 mask</text>
+ <text x="240" y="339" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">into the cell position of sdfMask</text>
+
+ <rect x="380" y="290" width="190" height="66" rx="6" fill="rgba(32,112,192,0.07)" stroke="#2070c0" stroke-width="1"/>
+ <text x="475" y="310" fill="#2070c0" font-size="11" font-family="monospace" text-anchor="middle">three texture layers</text>
+ <text x="475" y="326" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">sdfMask: glyph SHAPES (bilinear)</text>
+ <text x="475" y="339" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">sdfForeground + primary: colors</text>
+
+ <text x="60" y="392" fill="#999" font-size="9" font-family="monospace">why sans-serif bold: Courier's serifs and hairline strokes decay into unresolvable noise</text>
+ <text x="60" y="405" fill="#999" font-size="9" font-family="monospace">when the distance field is minified - uniform sturdy strokes survive</text>
+
+ <!-- why not mipmap note -->
+ <rect x="60" y="418" width="520" height="40" rx="6" fill="rgba(255,68,68,0.05)" stroke="#FF4444" stroke-width="1"/>
+ <text x="320" y="434" fill="#FF4444" font-size="10" font-family="monospace" text-anchor="middle">NO mipmaps on the mask: the edge gradient spans ~2 texels,</text>
+ <text x="320" y="448" fill="#FF4444" font-size="10" font-family="monospace" text-anchor="middle">half-res masks melt glyph edges - minification is analytic instead</text>
+</svg>
--- /dev/null
+<svg viewBox="0 0 640 420" width="640" height="420" xmlns="http://www.w3.org/2000/svg">
+ <defs>
+ <filter id="glow">
+ <feGaussianBlur stdDeviation="2" result="blur"/>
+ <feMerge>
+ <feMergeNode in="blur"/>
+ <feMergeNode in="SourceGraphic"/>
+ </feMerge>
+ </filter>
+ <marker id="arr2" viewBox="0 0 10 10" refX="9" refY="5" markerWidth="7" markerHeight="7" orient="auto-start-reverse">
+ <path d="M 0 0 L 10 5 L 0 10 z" fill="#40b0d0"/>
+ </marker>
+ </defs>
+
+ <rect width="640" height="420" fill="#061018"/>
+
+ <text x="320" y="30" fill="#40b0d0" font-size="16" font-family="monospace" text-anchor="middle" filter="url(#glow)">Minification: analytic coverage window</text>
+ <text x="320" y="48" fill="#999" font-size="10" font-family="monospace" text-anchor="middle">one screen pixel covering many texels still resolves the edge correctly</text>
+
+ <!-- screen pixel footprint diagram -->
+ <rect x="50" y="70" width="270" height="215" rx="6" fill="rgba(57,255,20,0.05)" stroke="#39FF14" stroke-width="1"/>
+ <text x="185" y="90" fill="#39FF14" font-size="11" font-family="monospace" text-anchor="middle">a screen pixel on the texture</text>
+
+ <!-- texel grid 6x5 -->
+ <g stroke="#1a3a4a" stroke-width="1">
+ <rect x="70" y="105" width="180" height="125"/>
+ <line x1="100" y1="105" x2="100" y2="230"/>
+ <line x1="130" y1="105" x2="130" y2="230"/>
+ <line x1="160" y1="105" x2="160" y2="230"/>
+ <line x1="190" y1="105" x2="190" y2="230"/>
+ <line x1="220" y1="105" x2="220" y2="230"/>
+ <line x1="70" y1="130" x2="250" y2="130"/>
+ <line x1="70" y1="155" x2="250" y2="155"/>
+ <line x1="70" y1="180" x2="250" y2="180"/>
+ <line x1="70" y1="205" x2="250" y2="205"/>
+ </g>
+ <!-- glyph edge crossing the grid -->
+ <line x1="90" y1="230" x2="230" y2="105" stroke="#c05088" stroke-width="2"/>
+ <!-- pixel footprint box -->
+ <rect x="115" y="130" width="90" height="75" fill="rgba(255,136,51,0.10)" stroke="#FF8833" stroke-width="2" stroke-dasharray="5 3"/>
+ <text x="160" y="245" fill="#FF8833" font-size="9" font-family="monospace" text-anchor="middle">footprint: many texels per pixel</text>
+ <text x="185" y="262" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">a bitmap would average to mush or alias;</text>
+ <text x="185" y="275" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">the field still knows where the edge is</text>
+
+ <!-- formula flow -->
+ <rect x="350" y="70" width="250" height="60" rx="6" fill="rgba(64,176,208,0.07)" stroke="#40b0d0" stroke-width="1.5"/>
+ <text x="475" y="92" fill="#40b0d0" font-size="10" font-family="monospace" text-anchor="middle">per-axis footprint from UV gradients</text>
+ <text x="475" y="106" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">footX = |dUV/dx|, footY = |dUV/dy|</text>
+ <text x="475" y="119" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">window follows the SHARPEST axis</text>
+
+ <line x1="475" y1="130" x2="475" y2="150" stroke="#40b0d0" stroke-width="1.5" marker-end="url(#arr2)"/>
+
+ <rect x="350" y="155" width="250" height="44" rx="6" fill="rgba(192,80,136,0.07)" stroke="#c05088" stroke-width="1.5"/>
+ <text x="475" y="173" fill="#c05088" font-size="10" font-family="monospace" text-anchor="middle">aaK = 2*spread / texelsPerPixel</text>
+ <text x="475" y="188" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">widens the coverage window as pixels grow</text>
+
+ <line x1="475" y1="199" x2="475" y2="219" stroke="#40b0d0" stroke-width="1.5" marker-end="url(#arr2)"/>
+
+ <rect x="350" y="224" width="250" height="66" rx="6" fill="rgba(255,136,51,0.07)" stroke="#FF8833" stroke-width="1.5"/>
+ <text x="475" y="242" fill="#FF8833" font-size="10" font-family="monospace" text-anchor="middle">perceptual corrections (minified text</text>
+ <text x="475" y="254" fill="#FF8833" font-size="10" font-family="monospace" text-anchor="middle">else reads as gray haze):</text>
+ <text x="475" y="270" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">SHARPEN x2: sub-pixel window kills halo</text>
+ <text x="475" y="283" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">coverage gamma < 1: stem darkening</text>
+
+ <!-- result strip -->
+ <rect x="60" y="310" width="520" height="90" rx="6" fill="rgba(57,255,20,0.05)" stroke="#39FF14" stroke-width="1"/>
+ <text x="320" y="332" fill="#39FF14" font-size="11" font-family="monospace" text-anchor="middle" filter="url(#glow)">result: graceful degradation</text>
+ <text x="320" y="350" fill="#999" font-size="10" font-family="monospace" text-anchor="middle">magnified: edges re-derived at display resolution - razor sharp</text>
+ <text x="320" y="365" fill="#999" font-size="10" font-family="monospace" text-anchor="middle">minified: coverage fades smoothly to clean gray, no crawling aliases</text>
+ <text x="320" y="380" fill="#999" font-size="10" font-family="monospace" text-anchor="middle">angled: the uncompressed axis keeps its sharpness</text>
+</svg>
--- /dev/null
+#+SETUPFILE: ~/.emacs.d/org-styles/html/darksun.theme
+#+TITLE: SDF Textures - Aukio 3D
+#+LANGUAGE: en
+#+LATEX_HEADER: \usepackage[margin=1.0in]{geometry}
+#+LATEX_HEADER: \usepackage{parskip}
+
+[[file:../index.html#outline-container-understanding-3d-engine][<- Back to index]]
+
+* What SDF textures are
+:PROPERTIES:
+:CUSTOM_ID: what-sdf-is
+:END:
+
+A regular texture stores *coverage*: each texel says "this much ink
+here". That is a photocopy of the glyph — resample it (magnify, minify,
+view at an angle) and the stored pixels blur or alias, because the
+information about /where the edge is/ was thrown away when the glyph
+was rasterized.
+
+A *signed distance field* (SDF) texture stores something smarter: per
+texel, the *distance to the nearest edge* — negative inside the ink,
+positive outside, zero exactly on the boundary. The rasterizer then
+re-derives coverage per screen pixel from this smooth field. The edge
+position survives resampling because the field around it is linear —
+bilinear interpolation of a linear ramp is exact.
+
+#+ATTR_HTML: :width 640
+[[file:SDF concept.svg]]
+
+In Aukio 3D the mask is a grayscale field in =texture.sdfMask=:
+
+- =0= — deep inside the ink
+- =127.5= — exactly on the edge
+- =255= — far outside any glyph
+
+The gradient spans only =SPREAD_TEXELS = 2.0= texels around the edge —
+that narrow band is all the rasterizer needs.
+
+Here is a real field, dumped straight from =SdfGlyphCache= (glyph "S",
+16x32 texels, upscaled 12x with nearest so you can see the texels):
+
+[[file:glyph-sdf-S.png]]
+
+Dark inside the strokes, bright outside, and a smooth gray ramp exactly
+two texels wide around the contour.
+
+* Generating glyph fields
+:PROPERTIES:
+:CUSTOM_ID: glyph-pipeline
+:END:
+
+=SdfGlyphCache= generates each character's distance field once and
+caches it in a =ConcurrentHashMap=; stamping a glyph into a canvas is
+then just a block copy.
+
+#+ATTR_HTML: :width 640
+[[file:SDF glyph pipeline.svg]]
+
+The steps:
+
+1. *Rasterize* the glyph with AWT at 4x the cell size (64x128 pixels)
+ with anti-aliasing on, using Liberation Mono Bold (metric-compatible
+ with Courier New, so the cell grid is unchanged). The font size is
+ auto-shrunk until the widest glyph fits the scratch without clipping
+ — a clipped glyph would corrupt the distance field at the cell edge.
+2. *Distance transform*: an exact Euclidean distance transform
+ (Felzenszwalb & Huttenlocher, two separable 1-D passes over parabola
+ envelopes) is run twice — once for distance to nearest ink pixel,
+ once for distance to nearest background pixel.
+3. *Sign, clamp, average*: signed distance = dOut - dIn, clamped to
+ +/-2 texels of spread, then the *field* (not coverage) is averaged
+ down to the 16x32 cell resolution. Averaging the field preserves the
+ edge position; averaging coverage would not.
+
+The font choice matters: Courier's serifs and hairline strokes decay
+into unresolvable noise when the field is minified. A uniform-stroke
+bold sans-serif survives.
+
+* The rendering path
+:PROPERTIES:
+:CUSTOM_ID: render-path
+:END:
+
+When =texture.isSdf()= is true (an =sdfMask= is attached),
+=TexturedTriangle.paintSdf= takes over. Three layers are involved:
+
+| Layer | Contents | Sampling |
+|------------------+-----------------------------+----------|
+| =sdfMask= | glyph shapes (the field) | bilinear |
+| =sdfForeground= | ink color, flat per cell | nearest |
+| =primaryBitmap= | background color, per cell | nearest |
+
+Per screen pixel:
+
+1. Sample the mask bilinearly (fixed-point) -> distance =d=.
+2. Convert to coverage: =cov = (127.5 - d) * aaK + 128=, clamped to
+ [0, 256]. =aaK= scales the 2-texel gradient window to the current
+ pixel footprint (see next section).
+3. Blend: =pixel = bg * (1 - cov) + fg * cov=.
+
+Perspective-correct interpolation applies to SDF triangles exactly as
+it does to regular textured triangles — same affine-sufficiency test,
+same subdivided correction. See
+[[file:../Perspective correct textures/index.org][Perspective-correct
+textures]]; only the per-pixel sampling differs.
+
+* Minification without mipmaps
+:PROPERTIES:
+:CUSTOM_ID: minification
+:END:
+
+*There is deliberately no mipmap chain for SDF layers.* A distance
+field's edge gradient spans ~2 texels; a half-resolution mask melts the
+glyph edges. Worse, the two triangles of a rectangle cross mip
+thresholds at slightly different distances, producing a hard diagonal
+quality split and sudden blur steps while dollying (observed in
+practice).
+
+Minification is instead handled *analytically*: the coverage window is
+widened by the screen-space pixel footprint, giving area-correct
+coverage straight from the primary field.
+
+#+ATTR_HTML: :width 640
+[[file:SDF minification.svg]]
+
+The footprint is computed per axis from the screen-space UV gradients —
+=text on an angled plane is minified mostly along one axis=, and an
+isotropic average would blur the axis that still has resolution to
+spare. The coverage window follows the sharpest axis.
+
+Area-correct coverage alone reads as a low-contrast gray haze, so two
+perceptual corrections (A/B-tuned on far + angled text) kick in under
+minification:
+
+- *Sharpening* (=SDF_SHARPEN=, default 2): narrows the coverage window
+ below one pixel — kills the haze halo at the cost of slight shimmer.
+- *Coverage gamma* (< 1, automatic from the footprint): darkens stems
+ like a small-size font rasterizer, keeping thin strokes present.
+
+Real output, rendered headlessly through the [[file:../index.org::#snapshot][Snapshot tool]]:
+
+Magnified — edges re-derived at display resolution, razor sharp:
+
+[[file:sdf-near.png]]
+
+At moderate distance:
+
+[[file:sdf-mid.png]]
+
+Far away — small but clean, fading to gray instead of disintegrating
+into aliases (right: 4x nearest zoom of the center):
+
+[[file:sdf-far.png]]
+
+[[file:sdf-far-zoom.png]]
+
+At an oblique angle — foreshortened along one axis, still sharp along
+the other:
+
+[[file:sdf-angled.png]]
+
+* Using it
+:PROPERTIES:
+:CUSTOM_ID: using-sdf
+:END:
+
+*TextCanvas* is the main entry point: a textured rectangle carrying a
+character grid in 3D space. World cell size 8x16 units, texture cell
+16x32 texels (2 texels per world unit).
+
+#+BEGIN_SRC java
+Transform location = new Transform(new Point3D(0, 0, 500));
+TextCanvas canvas = new TextCanvas(location, "Hello, World!",
+ Color.WHITE, Color.BLACK);
+shapeCollection.addShape(canvas);
+
+// blank canvas + cursor writing
+TextCanvas blank = new TextCanvas(location, new TextPointer(10, 40),
+ Color.GREEN, Color.BLACK);
+blank.locate(0, 0);
+blank.print("Line 1");
+blank.locate(1, 0);
+blank.print("Line 2");
+blank.setForegroundColor(Color.RED); // affects subsequent writes
+blank.setTextColor(Color.CYAN); // recolors existing ink only
+#+END_SRC
+
+Colors are per-cell: each =putChar= fills the cell's rectangle in the
+background and foreground layers, so one canvas can hold many colors.
+
+*ForwardOrientedTextBlock* renders the same pipeline onto a billboard
+that always faces the camera — for labels that must stay readable from
+any angle:
+
+#+BEGIN_SRC java
+ForwardOrientedTextBlock label = new ForwardOrientedTextBlock(
+ new Point3D(0, -50, 300), 1.0, 2, "Hello, World!", Color.RED);
+shapeCollection.addShape(label);
+#+END_SRC
+
+Real use in the demos: the life demo's help panel (=life_demo/Main.java=
+=createHelpPanel()=) and the axis labels in =CoordinateSystemDemo=.
+
+* Tuning knobs
+:PROPERTIES:
+:CUSTOM_ID: tuning
+:END:
+
+JVM properties (A/B tuning knobs in =TexturedTriangle=):
+
+| Property | Default | Effect |
+|-------------------+---------+-------------------------------------------|
+| =e3d.sdf.gamma= | 0 (auto) | fixed coverage gamma; auto derives from footprint |
+| =e3d.sdf.sharpen= | 2 | coverage window narrowing; 1 = pixel-exact |
+| =e3d.sdf.debug= | false | prints per-triangle footprints and path decisions to stderr |
+
+* Limitations
+:PROPERTIES:
+:CUSTOM_ID: limitations
+:END:
+
+- *Fixed cell grid*: TextCanvas is monospace by construction (16x32
+ texel cells). Proportional fonts would need a different stamping
+ scheme.
+- *ASCII-oriented cache*: =SdfGlyphCache= measures printable ASCII
+ (33..126) when sizing the font; exotic glyphs may fit worse.
+- *Under extreme minification* text fades to gray by design — that is
+ the correct physical answer (a sub-pixel glyph has no shape left),
+ but it means distant labels are decorative, not readable.
+- *Bandwidth under minification*: sampling the primary field (no mip
+ chain) costs more bandwidth per pixel. Text surfaces are small, so
+ this is the right trade — do not attach SDF masks to huge surfaces.
+
+* Related classes
+:PROPERTIES:
+:CUSTOM_ID: related-classes
+:END:
+
+| Class | Role |
+|-----------------------------+--------------------------------------------------|
+| [[file:../apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/composite/textcanvas/TextCanvas.html][TextCanvas]] | Character grid surface in 3D; owns the layers |
+| [[file:../apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/composite/textcanvas/SdfGlyphCache.html][SdfGlyphCache]] | Per-glyph field generation + cache (EDT inside) |
+| [[file:../apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/composite/ForwardOrientedTextBlock.html][ForwardOrientedTextBlock]] | Camera-facing text billboard |
+| [[file:../apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/basic/texturedpolygon/TexturedTriangle.html][TexturedTriangle]] | =paintSdf= — the scanline path |
+| [[file:../apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/texture/Texture.html][Texture]] | =sdfMask=, =sdfForeground=, =sdfSpreadTexels= |
+
+*See also:*
+
+- [[file:../Perspective correct textures/][Perspective-correct textures]] — the scanline texture-mapping path
+ that SDF rendering builds on; both paths live in =TexturedTriangle=
+ and share the same interpolated UVs.
+
--- /dev/null
+<svg viewBox="0 0 640 290" width="640" height="290" xmlns="http://www.w3.org/2000/svg">
+<defs>
+ <filter id="glows"><feGaussianBlur stdDeviation="1.5" result="blur"/><feMerge><feMergeNode in="blur"/><feMergeNode in="SourceGraphic"/></feMerge></filter>
+<mask id="imagine-text-gaps-2vose8" maskUnits="userSpaceOnUse"><rect x="0" y="0" width="640" height="290" fill="white"/><rect x="261.183349609375" y="6.583333969116211" width="117.63333129882812" height="20.91666603088379" fill="black" rx="2"/><rect x="110.16667175292969" y="26.25" width="419.6666564941406" height="15.083333015441895" fill="black" rx="2"/><rect x="53.083335876464844" y="223.25" width="83.83333587646484" height="15.083333015441895" fill="black" rx="2"/><rect x="54.900001525878906" y="237.6666717529297" width="80.19999694824219" height="16.25" fill="black" rx="2"/><rect x="35.608333587646484" y="252.4166717529297" width="118.78333282470703" height="13.916666984558105" fill="black" rx="2"/><rect x="257.9583435058594" y="223.25" width="100.08333587646484" height="15.083333015441895" fill="black" rx="2"/><rect x="273.9166564941406" y="237.6666717529297" width="68.16666793823242" height="16.25" fill="black" rx="2"/><rect x="267.875" y="252.4166717529297" width="80.25" height="13.916666984558105" fill="black" rx="2"/><rect x="463.8333435058594" y="223.25" width="116.33333587646484" height="15.083333015441895" fill="black" rx="2"/><rect x="487.9166564941406" y="237.6666717529297" width="68.16666793823242" height="16.25" fill="black" rx="2"/><rect x="477.058349609375" y="252.4166717529297" width="89.88333129882812" height="13.916666984558105" fill="black" rx="2"/><rect x="161.86666870117188" y="267.4166564941406" width="316.26666259765625" height="13.916666984558105" fill="black" rx="2"/></mask></defs>
+<rect width="640" height="280" fill="#061018" style="fill:rgb(6, 16, 24);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+
+<text x="320" y="22" fill="#ccc" font-size="14" font-weight="700" font-family="monospace" text-anchor="middle" filter="url(#glows)" style="fill:rgb(204, 204, 204);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:14px;font-weight:700;text-anchor:middle;dominant-baseline:auto">Ambient Light</text>
+<text x="320" y="37" fill="#3a4a5a" font-size="9" font-family="monospace" text-anchor="middle" style="fill:rgb(58, 74, 90);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:9px;font-weight:400;text-anchor:middle;dominant-baseline:auto">base illumination applied to all surfaces equally, regardless of orientation</text>
+
+<line x1="213" y1="42" x2="213" y2="268" stroke="#0c1a26" stroke-width="1.5" mask="url(#imagine-text-gaps-2vose8)" style="fill:rgb(0, 0, 0);stroke:rgb(12, 26, 38);color:rgb(251, 251, 254);stroke-width:1.5px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+<line x1="427" y1="42" x2="427" y2="268" stroke="#0c1a26" stroke-width="1.5" mask="url(#imagine-text-gaps-2vose8)" style="fill:rgb(0, 0, 0);stroke:rgb(12, 26, 38);color:rgb(251, 251, 254);stroke-width:1.5px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+<line x1="5" y1="220" x2="208" y2="220" stroke="#0c1a26" stroke-width="1" style="fill:rgb(0, 0, 0);stroke:rgb(12, 26, 38);color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
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+<line x1="432" y1="220" x2="635" y2="220" stroke="#0c1a26" stroke-width="1" style="fill:rgb(0, 0, 0);stroke:rgb(12, 26, 38);color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+
+<!-- PANEL 1: No ambient -->
+<circle cx="30" cy="57" r="7" fill="rgba(255,102,0,0.45)" stroke="#FF6600" stroke-width="1.5" style="fill:rgba(255, 102, 0, 0.45);stroke:rgb(255, 102, 0);color:rgb(251, 251, 254);stroke-width:1.5px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
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+<text x="95" y="234" fill="rgba(208,64,64,0.75)" font-size="9" font-family="monospace" text-anchor="middle" style="fill:rgba(208, 64, 64, 0.75);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:9px;font-weight:400;text-anchor:middle;dominant-baseline:auto">Color(0, 0, 0)</text>
+<text x="95" y="249" fill="rgba(208,64,64,0.9)" font-size="10" font-weight="700" font-family="monospace" text-anchor="middle" filter="url(#glows)" style="fill:rgba(208, 64, 64, 0.9);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:10px;font-weight:700;text-anchor:middle;dominant-baseline:auto">✗ pure black</text>
+<text x="95" y="262" fill="#3a4a5a" font-size="8" font-family="monospace" text-anchor="middle" style="fill:rgb(58, 74, 90);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:8px;font-weight:400;text-anchor:middle;dominant-baseline:auto">harsh shadows, no depth</text>
+
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+<line x1="243" y1="48" x2="243" y2="42" stroke="#FF6600" stroke-width="1.1" opacity="0.6" style="fill:rgb(0, 0, 0);stroke:rgb(255, 102, 0);color:rgb(251, 251, 254);stroke-width:1.1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:0.6;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
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+<line x1="236" y1="51" x2="231" y2="46" stroke="#FF6600" stroke-width="1.1" opacity="0.6" style="fill:rgb(0, 0, 0);stroke:rgb(255, 102, 0);color:rgb(251, 251, 254);stroke-width:1.1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:0.6;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
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+<text x="308" y="234" fill="#39FF14" font-size="9" font-family="monospace" text-anchor="middle" style="fill:rgb(57, 255, 20);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:9px;font-weight:400;text-anchor:middle;dominant-baseline:auto">Color(50, 50, 50)</text>
+<text x="308" y="249" fill="#39FF14" font-size="10" font-weight="700" font-family="monospace" text-anchor="middle" filter="url(#glows)" style="fill:rgb(57, 255, 20);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:10px;font-weight:700;text-anchor:middle;dominant-baseline:auto">✓ balanced</text>
+<text x="308" y="262" fill="#3a4a5a" font-size="8" font-family="monospace" text-anchor="middle" style="fill:rgb(58, 74, 90);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:8px;font-weight:400;text-anchor:middle;dominant-baseline:auto">depth preserved</text>
+
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+<line x1="464" y1="51" x2="469" y2="46" stroke="#FF6600" stroke-width="1.1" opacity="0.6" style="fill:rgb(0, 0, 0);stroke:rgb(255, 102, 0);color:rgb(251, 251, 254);stroke-width:1.1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:0.6;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+<line x1="450" y1="51" x2="445" y2="46" stroke="#FF6600" stroke-width="1.1" opacity="0.6" style="fill:rgb(0, 0, 0);stroke:rgb(255, 102, 0);color:rgb(251, 251, 254);stroke-width:1.1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:0.6;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
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+<polygon points="529,70 595,85 595,215 529,200" fill="rgba(85,145,92,0.72)" stroke="#30a050" stroke-width="1.5" style="fill:rgba(85, 145, 92, 0.72);stroke:rgb(48, 160, 80);color:rgb(251, 251, 254);stroke-width:1.5px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+<text x="522" y="234" fill="#FF6600" font-size="9" font-family="monospace" text-anchor="middle" style="fill:rgb(255, 102, 0);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:9px;font-weight:400;text-anchor:middle;dominant-baseline:auto">Color(150, 150, 150)</text>
+<text x="522" y="249" fill="#FF6600" font-size="10" font-weight="700" font-family="monospace" text-anchor="middle" filter="url(#glows)" style="fill:rgb(255, 102, 0);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:10px;font-weight:700;text-anchor:middle;dominant-baseline:auto">✗ too flat</text>
+<text x="522" y="262" fill="#3a4a5a" font-size="8" font-family="monospace" text-anchor="middle" style="fill:rgb(58, 74, 90);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:8px;font-weight:400;text-anchor:middle;dominant-baseline:auto">no depth contrast</text>
+
+<line x1="20" y1="268" x2="620" y2="268" stroke="#0c1a26" stroke-width="1" mask="url(#imagine-text-gaps-2vose8)" style="fill:rgb(0, 0, 0);stroke:rgb(12, 26, 38);color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:"Anthropic Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;font-size:16px;font-weight:400;text-anchor:start;dominant-baseline:auto"/>
+<text x="320" y="277" fill="#2a3a4a" font-size="8" font-family="monospace" text-anchor="middle" style="fill:rgb(42, 58, 74);stroke:none;color:rgb(251, 251, 254);stroke-width:1px;stroke-linecap:butt;stroke-linejoin:miter;opacity:1;font-family:monospace;font-size:8px;font-weight:400;text-anchor:middle;dominant-baseline:auto">lightingManager.setAmbientLight(new Color(50, 50, 50)) ← default</text>
+</svg>
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--- /dev/null
+<svg viewBox="0 0 640 295" width="640" height="295" xmlns="http://www.w3.org/2000/svg">
+<defs>
+ <filter id="glows"><feGaussianBlur stdDeviation="1.5" result="blur"/><feMerge><feMergeNode in="blur"/><feMergeNode in="SourceGraphic"/></feMerge></filter>
+ <marker id="ax" viewBox="0 0 8 8" refX="7" refY="4" markerWidth="5" markerHeight="5" orient="auto">
+ <path d="M 0 0 L 8 4 L 0 8 z" fill="#3a5060"/>
+ </marker>
+</defs>
+<rect width="640" height="295" fill="#061018"/>
+
+<text x="320" y="22" fill="#ccc" font-size="14" font-weight="700" font-family="monospace" text-anchor="middle" filter="url(#glows)">Distance Attenuation</text>
+<text x="320" y="37" fill="#3a4a5a" font-size="9" font-family="monospace" text-anchor="middle">light intensity falls off with distance from source</text>
+
+<line x1="400" y1="45" x2="400" y2="282" stroke="#0c1a26" stroke-width="1.5"/>
+
+<!-- Light source -->
+<circle cx="52" cy="110" r="22" fill="rgba(255,102,0,0.06)"/>
+<circle cx="52" cy="110" r="14" fill="rgba(255,102,0,0.2)" stroke="rgba(255,102,0,0.45)" stroke-width="1.5"/>
+<circle cx="52" cy="110" r="6" fill="rgba(255,102,0,0.7)" stroke="#FF6600" stroke-width="1.5"/>
+<line x1="52" y1="92" x2="52" y2="84" stroke="#FF6600" stroke-width="1.1" opacity="0.55"/>
+<line x1="65" y1="97" x2="72" y2="90" stroke="#FF6600" stroke-width="1.1" opacity="0.55"/>
+<line x1="39" y1="97" x2="32" y2="90" stroke="#FF6600" stroke-width="1.1" opacity="0.55"/>
+<line x1="70" y1="110" x2="78" y2="110" stroke="#FF6600" stroke-width="1.1" opacity="0.55"/>
+<line x1="65" y1="123" x2="72" y2="130" stroke="#FF6600" stroke-width="1.1" opacity="0.55"/>
+<text x="52" y="82" fill="#FF6600" font-size="9" font-weight="700" font-family="monospace" text-anchor="middle">Light</text>
+
+<line x1="52" y1="155" x2="380" y2="155" stroke="#1a2a3a" stroke-width="1" stroke-dasharray="4 3"/>
+
+<!-- Surface d=100, att=0.99 -->
+<line x1="65" y1="110" x2="126" y2="110" stroke="#FF6600" stroke-width="1" stroke-dasharray="4 2" opacity="0.40"/>
+<polygon points="128,77 163,77 158,148 133,148" fill="rgba(48,160,80,0.70)" stroke="#30a050" stroke-width="1.5"/>
+<text x="145" y="65" fill="#30a050" font-size="10" font-weight="700" font-family="monospace" text-anchor="middle" filter="url(#glows)">0.99</text>
+<line x1="145" y1="152" x2="145" y2="160" stroke="#2a3a4a" stroke-width="1"/>
+<text x="145" y="172" fill="#555" font-size="8" font-family="monospace" text-anchor="middle">d = 100</text>
+
+<!-- Surface d=300, att=0.52 -->
+<line x1="65" y1="110" x2="223" y2="110" stroke="#FF6600" stroke-width="1" stroke-dasharray="4 2" opacity="0.22"/>
+<polygon points="225,77 259,77 255,148 229,148" fill="rgba(48,160,80,0.36)" stroke="rgba(48,160,80,0.65)" stroke-width="1.2"/>
+<text x="242" y="65" fill="rgba(48,160,80,0.8)" font-size="10" font-weight="700" font-family="monospace" text-anchor="middle">0.52</text>
+<line x1="242" y1="152" x2="242" y2="160" stroke="#2a3a4a" stroke-width="1"/>
+<text x="242" y="172" fill="#555" font-size="8" font-family="monospace" text-anchor="middle">d = 300</text>
+
+<!-- Surface d=500, att=0.29 -->
+<line x1="65" y1="110" x2="316" y2="110" stroke="#FF6600" stroke-width="1" stroke-dasharray="4 2" opacity="0.10"/>
+<polygon points="318,77 352,77 349,148 321,148" fill="rgba(48,160,80,0.18)" stroke="rgba(48,160,80,0.38)" stroke-width="1"/>
+<text x="335" y="65" fill="rgba(48,160,80,0.55)" font-size="10" font-weight="700" font-family="monospace" text-anchor="middle">0.29</text>
+<line x1="335" y1="152" x2="335" y2="160" stroke="#2a3a4a" stroke-width="1"/>
+<text x="335" y="172" fill="#555" font-size="8" font-family="monospace" text-anchor="middle">d = 500</text>
+
+<text x="195" y="192" fill="#2a3a4a" font-size="8" font-family="monospace" text-anchor="middle">← attenuation factor shown above each surface →</text>
+
+<!-- Chart -->
+<text x="513" y="57" fill="#aaa" font-size="9" font-weight="700" font-family="monospace" text-anchor="middle">attenuation vs distance</text>
+<line x1="415" y1="210" x2="630" y2="210" stroke="#2a3a4a" stroke-width="1" marker-end="url(#ax)"/>
+<line x1="415" y1="210" x2="415" y2="67" stroke="#2a3a4a" stroke-width="1" marker-end="url(#ax)"/>
+<text x="622" y="222" fill="#3a5060" font-size="8" font-family="monospace">d</text>
+<text x="408" y="65" fill="#3a5060" font-size="8" font-family="monospace" text-anchor="end">att</text>
+<line x1="411" y1="210" x2="419" y2="210" stroke="#2a3a4a" stroke-width="1"/>
+<text x="408" y="213" fill="#3a5060" font-size="7" font-family="monospace" text-anchor="end">0</text>
+<line x1="411" y1="138" x2="419" y2="138" stroke="#2a3a4a" stroke-width="1"/>
+<line x1="415" y1="138" x2="625" y2="138" stroke="#0d1e2e" stroke-width="1"/>
+<text x="408" y="141" fill="#3a5060" font-size="7" font-family="monospace" text-anchor="end">0.5</text>
+<line x1="411" y1="67" x2="419" y2="67" stroke="#2a3a4a" stroke-width="1"/>
+<line x1="415" y1="67" x2="625" y2="67" stroke="#0d1e2e" stroke-width="1"/>
+<text x="408" y="70" fill="#3a5060" font-size="7" font-family="monospace" text-anchor="end">1.0</text>
+<line x1="450" y1="206" x2="450" y2="214" stroke="#2a3a4a" stroke-width="1"/>
+<line x1="450" y1="67" x2="450" y2="210" stroke="#0d1e2e" stroke-width="1" stroke-dasharray="2 4"/>
+<text x="450" y="222" fill="#3a5060" font-size="7" font-family="monospace" text-anchor="middle">100</text>
+<line x1="520" y1="206" x2="520" y2="214" stroke="#2a3a4a" stroke-width="1"/>
+<line x1="520" y1="67" x2="520" y2="210" stroke="#0d1e2e" stroke-width="1" stroke-dasharray="2 4"/>
+<text x="520" y="222" fill="#3a5060" font-size="7" font-family="monospace" text-anchor="middle">300</text>
+<line x1="590" y1="206" x2="590" y2="214" stroke="#2a3a4a" stroke-width="1"/>
+<line x1="590" y1="67" x2="590" y2="210" stroke="#0d1e2e" stroke-width="1" stroke-dasharray="2 4"/>
+<text x="590" y="222" fill="#3a5060" font-size="7" font-family="monospace" text-anchor="middle">500</text>
+<path d="M 415,67 C 430,67 440,68 450,68 C 468,68 492,100 520,136 C 548,170 575,175 625,178"
+ fill="none" stroke="#FF6600" stroke-width="2" opacity="0.85"/>
+<circle cx="415" cy="67" r="3" fill="#FF6600" opacity="0.70"/>
+<circle cx="450" cy="68" r="3" fill="#FF6600" opacity="0.85"/>
+<circle cx="520" cy="136" r="3" fill="#FF6600" opacity="0.85"/>
+<circle cx="590" cy="169" r="3" fill="#FF6600" opacity="0.85"/>
+<text x="453" y="62" fill="rgba(255,102,0,0.75)" font-size="7" font-family="monospace">0.99</text>
+<text x="523" y="131" fill="rgba(255,102,0,0.75)" font-size="7" font-family="monospace">0.52</text>
+<text x="593" y="164" fill="rgba(255,102,0,0.75)" font-size="7" font-family="monospace">0.29</text>
+
+<!-- Formula box -->
+<rect x="405" y="230" width="225" height="46" rx="4" fill="rgba(32,112,192,0.08)" stroke="#2070c0" stroke-width="1.5"/>
+<text x="517" y="249" fill="#2070c0" font-size="10" font-weight="700" font-family="monospace" text-anchor="middle">attenuation =</text>
+<text x="517" y="267" fill="#2070c0" font-size="11" font-family="monospace" text-anchor="middle">1 / (1 + 0.0001 · d²)</text>
+
+<line x1="20" y1="282" x2="620" y2="282" stroke="#0c1a26" stroke-width="1"/>
+<text x="320" y="291" fill="#2a3a4a" font-size="8" font-family="monospace" text-anchor="middle">coefficient 0.0001 was tuned for typical scene scales in Aukio 3D</text>
+</svg>
--- /dev/null
+<svg viewBox="0 0 640 480" width="640" height="480" xmlns="http://www.w3.org/2000/svg">
+<defs>
+ <filter id="glow"><feGaussianBlur stdDeviation="2" result="blur"/><feMerge><feMergeNode in="blur"/><feMergeNode in="SourceGraphic"/></feMerge></filter>
+ <filter id="glows"><feGaussianBlur stdDeviation="1.5" result="blur"/><feMerge><feMergeNode in="blur"/><feMergeNode in="SourceGraphic"/></feMerge></filter>
+ <marker id="an" viewBox="0 0 10 10" refX="10" refY="5" markerWidth="7" markerHeight="7" orient="auto"><path d="M 0 0 L 10 5 L 0 10 z" fill="#30a050"/></marker>
+ <marker id="al" viewBox="0 0 10 10" refX="10" refY="5" markerWidth="7" markerHeight="7" orient="auto"><path d="M 0 0 L 10 5 L 0 10 z" fill="#FF6600"/></marker>
+</defs>
+<rect width="640" height="480" fill="#061018"/>
+<text x="320" y="30" fill="#ccc" font-size="17" font-weight="700" font-family="monospace" text-anchor="middle" filter="url(#glows)">Lambert Cosine Law</text>
+<text x="320" y="48" fill="#3a4a5a" font-size="10" font-family="monospace" text-anchor="middle">how surface orientation determines light intensity</text>
+<line x1="385" y1="58" x2="385" y2="305" stroke="#0c1a26" stroke-width="1.5"/>
+<line x1="20" y1="308" x2="620" y2="308" stroke="#0c1a26" stroke-width="1.5"/>
+<polygon points="60,275 280,255 295,165 75,185" fill="none" stroke="rgba(48,160,80,0.15)" stroke-width="8"/>
+<polygon points="60,275 280,255 295,165 75,185" fill="rgba(48,160,80,0.13)" stroke="#30a050" stroke-width="2"/>
+<circle cx="178" cy="220" r="4" fill="#30a050"/>
+<line x1="178" y1="220" x2="148" y2="75" stroke="#30a050" stroke-width="2.5" marker-end="url(#an)"/>
+<text x="128" y="70" fill="#30a050" font-size="18" font-weight="700" font-family="monospace" filter="url(#glow)">N̂</text>
+<text x="130" y="84" fill="#aaa" font-size="9" font-family="monospace">normal</text>
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+<circle cx="345" cy="85" r="17" fill="rgba(255,102,0,0.2)" stroke="rgba(255,102,0,0.45)" stroke-width="1.5"/>
+<circle cx="345" cy="85" r="7" fill="rgba(255,102,0,0.7)" stroke="#FF6600" stroke-width="1.5"/>
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+<line x1="362" y1="67" x2="370" y2="60" stroke="#FF6600" stroke-width="1.2" opacity="0.55"/>
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+<line x1="368" y1="85" x2="377" y2="85" stroke="#FF6600" stroke-width="1.2" opacity="0.55"/>
+<line x1="322" y1="85" x2="313" y2="85" stroke="#FF6600" stroke-width="1.2" opacity="0.55"/>
+<text x="370" y="89" fill="#FF6600" font-size="11" font-weight="700" font-family="monospace" text-anchor="start">Light</text>
+<line x1="333" y1="97" x2="185" y2="215" stroke="#FF6600" stroke-width="2" stroke-dasharray="6 3" marker-end="url(#al)"/>
+<text x="274" y="147" fill="#FF6600" font-size="15" font-weight="700" font-family="monospace" filter="url(#glow)">L̂</text>
+<path d="M 167,166 A 55,55 0 0,1 221,185" fill="none" stroke="#b09020" stroke-width="2"/>
+<text x="213" y="160" fill="#b09020" font-size="14" font-weight="700" font-family="monospace" filter="url(#glows)">θ</text>
+<text x="178" y="244" fill="rgba(48,160,80,0.6)" font-size="10" font-family="monospace" text-anchor="middle">surface polygon</text>
+<rect x="398" y="68" width="218" height="105" rx="4" fill="rgba(32,112,192,0.08)" stroke="#2070c0" stroke-width="1.5"/>
+<text x="507" y="93" fill="#2070c0" font-size="12" font-weight="700" font-family="monospace" text-anchor="middle">brightness =</text>
+<text x="507" y="118" fill="#2070c0" font-size="16" font-weight="700" font-family="monospace" text-anchor="middle" filter="url(#glows)">dot( N̂ , L̂ )</text>
+<line x1="408" y1="127" x2="606" y2="127" stroke="#2070c0" stroke-width="1" opacity="0.3"/>
+<text x="507" y="152" fill="#2070c0" font-size="13" font-family="monospace" text-anchor="middle">= cos( θ )</text>
+<rect x="398" y="183" width="218" height="115" rx="4" fill="rgba(80,96,192,0.05)" stroke="rgba(80,96,192,0.4)" stroke-width="1"/>
+<text x="412" y="204" fill="#666" font-size="10" font-family="monospace">θ = 0°</text>
+<rect x="458" y="193" width="80" height="13" rx="2" fill="rgba(57,255,20,0.15)" stroke="#39FF14" stroke-width="1"/>
+<rect x="458" y="193" width="80" height="13" rx="2" fill="rgba(57,255,20,0.7)"/>
+<text x="548" y="204" fill="#39FF14" font-size="10" font-weight="700" font-family="monospace">1.00</text>
+<text x="412" y="225" fill="#666" font-size="10" font-family="monospace">θ = 45°</text>
+<rect x="458" y="214" width="80" height="13" rx="2" fill="rgba(48,160,80,0.08)" stroke="#30a050" stroke-width="1"/>
+<rect x="458" y="214" width="57" height="13" rx="2" fill="rgba(48,160,80,0.55)"/>
+<text x="548" y="225" fill="#bbb" font-size="10" font-family="monospace">0.71</text>
+<text x="412" y="246" fill="#666" font-size="10" font-family="monospace">θ = 90°</text>
+<rect x="458" y="235" width="80" height="13" rx="2" fill="rgba(48,160,80,0.04)" stroke="rgba(48,160,80,0.2)" stroke-width="1"/>
+<text x="548" y="246" fill="#555" font-size="10" font-family="monospace">0.00</text>
+<line x1="408" y1="255" x2="606" y2="255" stroke="rgba(80,96,192,0.3)" stroke-width="1"/>
+<text x="412" y="271" fill="#555" font-size="10" font-family="monospace">θ > 90°</text>
+<text x="460" y="271" fill="rgba(208,64,64,0.75)" font-size="10" font-family="monospace">back-face → skip</text>
+<text x="412" y="287" fill="#3a4a5a" font-size="9" font-family="monospace">dot < 0 → no contribution</text>
+<text x="320" y="326" fill="#2a3a4a" font-size="10" font-family="monospace" text-anchor="middle">— angle examples —</text>
+<g transform="translate(40,338)">
+ <rect x="10" y="78" width="100" height="13" rx="2" fill="rgba(48,160,80,0.25)" stroke="#30a050" stroke-width="1.5"/>
+ <line x1="60" y1="78" x2="60" y2="32" stroke="#30a050" stroke-width="2" marker-end="url(#an)"/>
+ <circle cx="60" cy="13" r="7" fill="rgba(255,102,0,0.5)" stroke="#FF6600" stroke-width="1.5"/>
+ <line x1="60" y1="20" x2="60" y2="34" stroke="#FF6600" stroke-width="2" marker-end="url(#al)"/>
+ <text x="60" y="103" fill="#39FF14" font-size="11" font-weight="700" font-family="monospace" text-anchor="middle">θ = 0°</text>
+ <rect x="10" y="112" width="100" height="11" rx="2" fill="rgba(48,160,80,0.15)" stroke="#30a050" stroke-width="1"/>
+ <rect x="10" y="112" width="100" height="11" rx="2" fill="#30a050"/>
+ <text x="60" y="121" fill="#061018" font-size="8" font-weight="700" font-family="monospace" text-anchor="middle">100%</text>
+</g>
+<g transform="translate(250,338)">
+ <rect x="10" y="78" width="100" height="13" rx="2" fill="rgba(48,160,80,0.15)" stroke="#30a050" stroke-width="1.5"/>
+ <line x1="60" y1="78" x2="60" y2="32" stroke="#30a050" stroke-width="2" marker-end="url(#an)"/>
+ <circle cx="104" cy="34" r="7" fill="rgba(255,102,0,0.5)" stroke="#FF6600" stroke-width="1.5"/>
+ <line x1="99" y1="39" x2="68" y2="70" stroke="#FF6600" stroke-width="2" marker-end="url(#al)"/>
+ <path d="M 60,50 A 28,28 0 0,1 80,58" fill="none" stroke="#b09020" stroke-width="1.5"/>
+ <text x="83" y="51" fill="#b09020" font-size="9" font-weight="700" font-family="monospace">45°</text>
+ <text x="60" y="103" fill="#bbb" font-size="11" font-weight="700" font-family="monospace" text-anchor="middle">θ = 45°</text>
+ <rect x="10" y="112" width="100" height="11" rx="2" fill="rgba(48,160,80,0.08)" stroke="#30a050" stroke-width="1"/>
+ <rect x="10" y="112" width="71" height="11" rx="2" fill="rgba(48,160,80,0.55)"/>
+ <text x="60" y="121" fill="#ccc" font-size="8" font-weight="700" font-family="monospace" text-anchor="middle">71%</text>
+</g>
+<g transform="translate(462,338)">
+ <rect x="10" y="78" width="100" height="13" rx="2" fill="rgba(208,64,64,0.06)" stroke="rgba(208,64,64,0.4)" stroke-width="1.5" stroke-dasharray="4 3"/>
+ <line x1="60" y1="78" x2="60" y2="32" stroke="#30a050" stroke-width="2" marker-end="url(#an)"/>
+ <circle cx="122" cy="78" r="7" fill="rgba(255,102,0,0.5)" stroke="#FF6600" stroke-width="1.5"/>
+ <line x1="115" y1="78" x2="76" y2="78" stroke="#FF6600" stroke-width="2" marker-end="url(#al)"/>
+ <path d="M 60,50 A 28,28 0 0,1 88,78" fill="none" stroke="#b09020" stroke-width="1.5"/>
+ <text x="80" y="57" fill="#b09020" font-size="9" font-weight="700" font-family="monospace">90°</text>
+ <text x="60" y="103" fill="rgba(208,64,64,0.8)" font-size="11" font-weight="700" font-family="monospace" text-anchor="middle">θ = 90°</text>
+ <rect x="10" y="112" width="100" height="11" rx="2" fill="rgba(208,64,64,0.05)" stroke="rgba(208,64,64,0.4)" stroke-width="1" stroke-dasharray="3 2"/>
+ <text x="60" y="121" fill="rgba(208,64,64,0.7)" font-size="8" font-weight="700" font-family="monospace" text-anchor="middle">0% (skip)</text>
+</g>
+<line x1="40" y1="472" x2="62" y2="472" stroke="#30a050" stroke-width="2"/>
+<text x="68" y="476" fill="#30a050" font-size="9" font-family="monospace">N̂ surface normal</text>
+<line x1="250" y1="472" x2="272" y2="472" stroke="#FF6600" stroke-width="2" stroke-dasharray="5 2"/>
+<text x="278" y="476" fill="#FF6600" font-size="9" font-family="monospace">L̂ light direction</text>
+</svg>
--- /dev/null
+<svg viewBox="0 0 620 80" width="620" height="80" xmlns="http://www.w3.org/2000/svg">
+ <defs>
+ <marker id="arrowhead2" viewBox="0 0 10 10" refX="9" refY="5"
+ markerWidth="6" markerHeight="6" orient="auto">
+ <path d="M 0 0 L 10 5 L 0 10 z" fill="#30a050"/>
+ </marker>
+ </defs>
+ <rect width="620" height="80" fill="#061018"/>
+
+ <!-- Transform phase (where shading happens) -->
+ <rect x="140" y="25" width="90" height="30" rx="3" fill="rgba(176,144,32,0.15)" stroke="#b09020" stroke-width="2"/>
+ <text x="185" y="43" fill="#b09020" font-size="10" font-weight="700" font-family="monospace" text-anchor="middle">Transform</text>
+ <text x="185" y="67" fill="#b09020" font-size="8" font-family="monospace" text-anchor="middle">compute lighting</text>
+
+ <!-- Other phases -->
+ <rect x="15" y="25" width="90" height="30" rx="3" fill="rgba(48,160,80,0.15)" stroke="#30a050" stroke-width="1.5"/>
+ <text x="60" y="43" fill="#30a050" font-size="10" font-weight="700" font-family="monospace" text-anchor="middle">Shapes</text>
+
+ <rect x="265" y="25" width="70" height="30" rx="3" fill="rgba(200,80,140,0.15)" stroke="#c05088" stroke-width="1.5"/>
+ <text x="300" y="43" fill="#c05088" font-size="10" font-weight="700" font-family="monospace" text-anchor="middle">Sort</text>
+
+ <rect x="365" y="25" width="80" height="30" rx="3" fill="rgba(255,102,0,0.15)" stroke="#FF6600" stroke-width="1.5"/>
+ <text x="405" y="43" fill="#FF6600" font-size="10" font-weight="700" font-family="monospace" text-anchor="middle">Paint</text>
+ <text x="405" y="67" fill="#bbb" font-size="8" font-family="monospace" text-anchor="middle">use cached color</text>
+
+ <rect x="480" y="25" width="60" height="30" rx="3" fill="rgba(57,255,20,0.15)" stroke="#39FF14" stroke-width="1.5"/>
+ <text x="510" y="43" fill="#39FF14" font-size="10" font-weight="700" font-family="monospace" text-anchor="middle">Blit</text>
+
+ <!-- Arrows -->
+ <line x1="105" y1="40" x2="135" y2="40" stroke="#30a050" stroke-width="1.5" marker-end="url(#arrowhead2)"/>
+ <line x1="230" y1="40" x2="260" y2="40" stroke="#2070c0" stroke-width="1.5" marker-end="url(#arrowhead2)"/>
+ <line x1="335" y1="40" x2="360" y2="40" stroke="#c05088" stroke-width="1.5" marker-end="url(#arrowhead2)"/>
+ <line x1="445" y1="40" x2="475" y2="40" stroke="#FF6600" stroke-width="1.5" marker-end="url(#arrowhead2)"/>
+ <line x1="540" y1="40" x2="565" y2="40" stroke="#39FF14" stroke-width="1.5" marker-end="url(#arrowhead2)"/>
+</svg>
--- /dev/null
+#+SETUPFILE: ~/.emacs.d/org-styles/html/darksun.theme
+#+TITLE: Shading & Lighting - Aukio 3D
+#+LANGUAGE: en
+#+LATEX_HEADER: \usepackage[margin=1.0in]{geometry}
+#+LATEX_HEADER: \usepackage{parskip}
+#+LATEX_HEADER: \usepackage[none]{hyphenat}
+
+#+OPTIONS: H:20 num:20
+#+OPTIONS: author:nil
+
+#+HTML_HEAD: <link rel="stylesheet" href="../style.css"/>
+
+[[file:../index.html#outline-container-understanding-3d-engine][<- Back to index]]
+
+* Overview
+:PROPERTIES:
+:CUSTOM_ID: shading-lighting
+:END:
+
+#+attr_html: :class responsive-img
+#+attr_latex: :width 1000px
+[[file:Shaded sphere.png]]
+
+*Aukio 3D* implements *flat shading* using the [[https://en.wikipedia.org/wiki/Lambert%27s_cosine_law][Lambert cosine
+law]]. Each polygon receives a single color based on its orientation
+relative to light sources. This is a simple yet effective lighting
+model that gives 3D objects depth and realism.
+
+** The Lighting Model: Lambert Cosine Law
+:PROPERTIES:
+:CUSTOM_ID: lambert-cosine-law
+:END:
+
+#+INCLUDE: "Lambert cosine law.svg" export html
+
+The *Lambert cosine law* determines how much light a surface receives
+based on its orientation. A surface facing directly toward a light source
+receives maximum illumination; as it tilts away, the illumination decreases
+proportionally until it reaches zero when perpendicular to the light
+direction. This fundamental principle creates the visual cues that make 3D
+objects appear solid and dimensional rather than flat.
+
+The engine implements this law through the dot product of two vectors. The
+[[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/lighting/LightingManager.html][LightingManager]] computes a unit vector pointing from the polygon's center
+to each [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/lighting/LightSource.html][LightSource]], then calculates the dot product with the surface
+normal. When the dot product equals 1.0, the surface faces the light
+directly and receives full brightness. At 0.71 (a 45-degree angle), it
+receives about 71% illumination. At zero or below, the surface faces away
+from the light and receives no direct contribution from that source. The
+implementation in [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/lighting/LightingManager.html][LightingManager.computeLighting()]] explicitly checks for
+positive dot products before adding light contributions, ensuring that
+back-facing surfaces skip unnecessary calculations.
+
+The surface normal itself is computed by [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/geometry/Plane.html#computeNormal()][Plane.computeNormal()]], which takes
+the first three vertices of a polygon and calculates their cross product to
+find the perpendicular direction. This normal, along with the polygon's
+center point calculated by [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/basic/solidpolygon/SolidPolygon.html][SolidPolygon]], is passed to the lighting manager
+during the [[file:../Rendering loop/][transform phase]] of the rendering loop. The transform phase runs
+in parallel, but each polygon is transformed by exactly one worker per
+pass, so its cached =shadedColor= field has a single writer — the
+result is reused allocation-free during the subsequent multi-threaded
+paint phase. See the
+[[file:../index.org::#normal-vector][Normal Vector]] section for more details on how normals are computed and used
+throughout the engine.
+
+* Light Sources
+:PROPERTIES:
+:CUSTOM_ID: light-sources
+:END:
+
+Each light source has three properties:
+
+| Property | Description |
+|------------+--------------------------------------|
+| Position | 3D world coordinates of the light |
+| Color | RGB color of emitted light |
+| Intensity | Brightness multiplier (1.0 = normal) |
+
+#+BEGIN_SRC java
+import eu.svjatoslav.aukio.e3d.renderer.raster.lighting.LightSource;
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+
+// Create a bright yellow light to the right
+LightSource rightLight = new LightSource(
+ new Point3D(200, -100, 0), // position: right, above, at viewer level
+ Color.YELLOW, // color
+ 2.0 // intensity: extra bright
+);
+
+// Create a dim blue light from the left
+LightSource leftLight = new LightSource(
+ new Point3D(-150, 50, 100),
+ Color.BLUE,
+ 0.5 // intensity: dim
+);
+#+END_SRC
+
+Multiple light sources add their contributions together, allowing for
+complex lighting setups like the screenshot above showing a sphere lit
+by two lights from the right.
+
+** Distance Attenuation
+:PROPERTIES:
+:CUSTOM_ID: distance-attenuation
+:END:
+
+#+INCLUDE: "Distance attenuation.svg" export html
+
+Light intensity decreases with distance using a *simplified inverse
+square law*:
+
+#+BEGIN_SRC
+attenuation = 1.0 / (1.0 + 0.0001 * distance²)
+#+END_SRC
+
+- At distance 0: attenuation = 1.0 (full intensity)
+- At distance 100: attenuation ≈ 0.99 (almost full)
+- At distance 300: attenuation ≈ 0.52 (half intensity)
+- At distance 500: attenuation ≈ 0.29 (about 30%)
+
+This simplified formula prevents harsh cutoffs while still providing
+distance-based dimming. The =0.0001= coefficient was tuned for typical
+scene scales in Aukio 3D.
+
+* Ambient Light
+:PROPERTIES:
+:CUSTOM_ID: ambient-light
+:END:
+
+#+INCLUDE: "Ambient light comparison.svg" export html
+
+*Ambient light* provides base illumination that affects all surfaces
+equally, regardless of orientation. Without ambient light, surfaces not
+directly facing a light source would be pure black.
+
+- Default ambient: =Color(50, 50, 50)= (dim gray) — set by the ViewPanel
+ constructor; a standalone =new LightingManager()= starts at
+ =Color(10, 10, 10)=
+- Configurable via =lightingManager.setAmbientLight()=
+- Too much ambient: flat appearance (no contrast)
+- Too little ambient: harsh shadows (pure black areas)
+
+#+BEGIN_SRC java
+// Increase ambient for softer shadows
+viewPanel.getLightingManager().setAmbientLight(new Color(80, 80, 80));
+
+// Reduce ambient for dramatic contrast
+viewPanel.getLightingManager().setAmbientLight(new Color(20, 20, 20));
+#+END_SRC
+
+* Using Shading in Your Scene
+:PROPERTIES:
+:CUSTOM_ID: using-shading
+:END:
+
+**Adding light sources:**
+
+#+BEGIN_SRC java
+import eu.svjatoslav.aukio.e3d.gui.ViewPanel;
+import eu.svjatoslav.aukio.e3d.renderer.raster.lighting.LightSource;
+
+ViewPanel viewPanel = new ViewPanel();
+
+// Get the lighting manager
+LightingManager lighting = viewPanel.getLightingManager();
+
+// Add light sources
+lighting.addLight(new LightSource(
+ new Point3D(200, -100, 0), // right side, above
+ Color.YELLOW,
+ 1.5 // bright
+));
+
+lighting.addLight(new LightSource(
+ new Point3D(-100, 0, 200), // left side, further away
+ new Color(255, 200, 150), // warm white
+ 1.0
+));
+
+// Configure ambient light
+lighting.setAmbientLight(new Color(40, 40, 40));
+#+END_SRC
+
+**Enabling shading on shapes:**
+
+#+BEGIN_SRC java
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.solid.SolidPolygonRectangularBox;
+
+// Create a shaded box
+SolidPolygonRectangularBox box = new SolidPolygonRectangularBox(
+ new Point3D(-50, -50, 100), // min corner
+ new Point3D(50, 50, 200), // max corner
+ Color.RED
+);
+
+// Enable shading on the box and all its sub-polygons
+box.setShadingEnabled(true);
+
+// Also enable backface culling for closed meshes
+box.setBackfaceCulling(true);
+
+// Add to scene
+viewPanel.getRootShapeCollection().addShape(box);
+#+END_SRC
+
+Shading propagates through composite shapes — calling
+[[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/composite/base/AbstractCompositeShape.html#setShadingEnabled(boolean)][setShadingEnabled(true)]] on a composite enables shading for all its
+sub-polygons.
+
+** Related Classes
+:PROPERTIES:
+:CUSTOM_ID: related-classes
+:END:
+
+| Class | Purpose |
+|-------+---------|
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/lighting/LightingManager.html][LightingManager]] | Manages light sources and computes shading |
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/lighting/LightSource.html][LightSource]] | Individual light with position, color, intensity |
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/basic/solidpolygon/SolidPolygon.html][SolidPolygon]] | Polygon shape with shading support |
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/composite/base/AbstractCompositeShape.html][AbstractCompositeShape]] | Composite shape with shading propagation |
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/gui/ViewPanel.html][ViewPanel]] | Provides access to LightingManager |
+* Implementation details
+:PROPERTIES:
+:CUSTOM_ID: implementation-details
+:END:
+
+#+INCLUDE: "Shading pipeline.svg" export html
+
+Lighting is computed during *Phase 1* (transform phase) of the
+[[file:../Rendering loop/][rendering loop]]:
+
+1. Each shaded polygon calculates its center point and surface normal
+2. [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/lighting/LightingManager.html][LightingManager]] computes lighting from all sources
+3. Result stored in reusable =shadedColor= field
+4. During *Phase 4* (paint), the cached color is used directly
+
+**Why during transform phase?**
+
+- Lighting computed *once per polygon per pass* — not per pixel
+- Each polygon is transformed by a single worker, so its cached result
+ has exactly one writer even though the transform phase runs in parallel
+- Result reused during multi-threaded paint phase — efficient
+
+** Performance Characteristics
+:PROPERTIES:
+:CUSTOM_ID: performance
+:END:
+
+| Aspect | Cost |
+|--------------+-------------------------------|
+| Computation | Per polygon, not per pixel |
+| Phase | Parallel transform (single writer per polygon) |
+| Allocation | Zero (reuses Color instance) |
+| Cache | One shadedColor per polygon |
+
+The shading implementation is optimized for CPU rendering:
+
+- *Flat shading*: One lighting calculation per polygon (N-vertex polygon = 1 calculation)
+- *Reusable Color*: Result stored in existing field, no allocation during render
+- *Thread-safe*: One writer per polygon per pass, so no synchronization needed
+- *Pre-computed*: All paint workers (tile grid, ~75% of CPU cores by default) read the same cached result
+
+This approach trades visual fidelity (no per-pixel lighting) for
+performance — essential for software rendering where per-pixel lighting
+would be prohibitively expensive.
--- /dev/null
+<svg viewBox="0 0 640 460" width="640" height="460" xmlns="http://www.w3.org/2000/svg">
+ <defs>
+ <filter id="glow">
+ <feGaussianBlur stdDeviation="2" result="blur"/>
+ <feMerge>
+ <feMergeNode in="blur"/>
+ <feMergeNode in="SourceGraphic"/>
+ </feMerge>
+ </filter>
+ </defs>
+
+ <!-- background -->
+ <rect width="640" height="460" fill="#061018"/>
+
+ <!-- faint grid -->
+ <g stroke="#1a3a4a" stroke-width="0.5">
+ <line x1="60" y1="60" x2="600" y2="60"/>
+ <line x1="60" y1="130" x2="600" y2="130"/>
+ <line x1="60" y1="200" x2="600" y2="200"/>
+ <line x1="60" y1="270" x2="600" y2="270"/>
+ <line x1="60" y1="340" x2="600" y2="340"/>
+ <line x1="60" y1="410" x2="600" y2="410"/>
+ </g>
+
+ <text x="320" y="34" fill="#40b0d0" font-size="17" font-family="monospace" text-anchor="middle" filter="url(#glow)">Two parallel cameras, one screen</text>
+ <text x="320" y="52" fill="#999" font-size="10" font-family="monospace" text-anchor="middle">top-down view of the scene (z grows downward = into the scene)</text>
+
+ <!-- projection plane line (screen) -->
+ <line x1="100" y1="140" x2="560" y2="140" stroke="#c05088" stroke-width="2" filter="url(#glow)"/>
+ <text x="560" y="130" fill="#c05088" font-size="10" font-family="monospace" text-anchor="end">screen plane (per eye)</text>
+
+ <!-- world objects -->
+ <circle cx="330" cy="240" r="8" fill="#FF8833" filter="url(#glow)"/>
+ <text x="330" y="262" fill="#FF8833" font-size="10" font-family="monospace" text-anchor="middle">near object</text>
+ <circle cx="330" cy="380" r="8" fill="#2070c0" filter="url(#glow)"/>
+ <text x="330" y="402" fill="#2070c0" font-size="10" font-family="monospace" text-anchor="middle">far object</text>
+
+ <!-- eyes -->
+ <circle cx="240" cy="70" r="7" fill="#39FF14" filter="url(#glow)"/>
+ <text x="222" y="74" fill="#39FF14" font-size="11" font-family="monospace" text-anchor="end">left eye</text>
+ <text x="222" y="88" fill="#39FF14" font-size="9" font-family="monospace" text-anchor="end">x - IPD/2</text>
+ <circle cx="420" cy="70" r="7" fill="#40b0d0" filter="url(#glow)"/>
+ <text x="438" y="74" fill="#40b0d0" font-size="11" font-family="monospace">right eye</text>
+ <text x="438" y="88" fill="#40b0d0" font-size="9" font-family="monospace">x + IPD/2</text>
+
+ <!-- IPD brace -->
+ <line x1="240" y1="98" x2="420" y2="98" stroke="#b09020" stroke-width="1.5" filter="url(#glow)"/>
+ <line x1="240" y1="92" x2="240" y2="104" stroke="#b09020" stroke-width="1.5"/>
+ <line x1="420" y1="92" x2="420" y2="104" stroke="#b09020" stroke-width="1.5"/>
+ <text x="330" y="92" fill="#b09020" font-size="11" font-family="monospace" text-anchor="middle" filter="url(#glow)">IPD = 6.5 units (cm)</text>
+
+ <!-- rays: left eye -->
+ <line x1="240" y1="70" x2="330" y2="240" stroke="#39FF14" stroke-width="1.5" stroke-opacity="0.8"/>
+ <line x1="240" y1="70" x2="330" y2="380" stroke="#39FF14" stroke-width="1" stroke-opacity="0.45" stroke-dasharray="5 3"/>
+ <!-- rays: right eye -->
+ <line x1="420" y1="70" x2="330" y2="240" stroke="#40b0d0" stroke-width="1.5" stroke-opacity="0.8"/>
+ <line x1="420" y1="70" x2="330" y2="380" stroke="#40b0d0" stroke-width="1" stroke-opacity="0.45" stroke-dasharray="5 3"/>
+
+ <!-- projections of the near object on the screen plane -->
+ <!-- left eye: ray from (240,70) to (330,240); at y=140: t=(140-70)/(240-70)=0.4118, x=240+0.4118*90=277 -->
+ <circle cx="277" cy="140" r="4" fill="#FF8833" stroke="#39FF14" stroke-width="1.5" filter="url(#glow)"/>
+ <!-- right eye: ray from (420,70) to (330,240); at y=140: x=420-0.4118*90=383 -->
+ <circle cx="383" cy="140" r="4" fill="#FF8833" stroke="#40b0d0" stroke-width="1.5" filter="url(#glow)"/>
+ <!-- projections of the far object -->
+ <!-- left: (240,70)->(330,380); t=(140-70)/(380-70)=0.2258; x=240+0.2258*90=260 -->
+ <circle cx="260" cy="140" r="3.5" fill="#2070c0" stroke="#39FF14" stroke-width="1.5"/>
+ <!-- right: x=420-0.2258*90=400 -->
+ <circle cx="400" cy="140" r="3.5" fill="#2070c0" stroke="#40b0d0" stroke-width="1.5"/>
+
+ <!-- disparity braces on the screen plane -->
+ <line x1="277" y1="152" x2="383" y2="152" stroke="#FF8833" stroke-width="1.5" filter="url(#glow)"/>
+ <line x1="277" y1="147" x2="277" y2="157" stroke="#FF8833" stroke-width="1.5"/>
+ <line x1="383" y1="147" x2="383" y2="157" stroke="#FF8833" stroke-width="1.5"/>
+ <text x="330" y="168" fill="#FF8833" font-size="10" font-family="monospace" text-anchor="middle">large disparity = close</text>
+ <line x1="260" y1="126" x2="400" y2="126" stroke="#2070c0" stroke-width="1" stroke-opacity="0.9"/>
+ <text x="330" y="120" fill="#2070c0" font-size="10" font-family="monospace" text-anchor="middle">small disparity = far</text>
+
+ <text x="60" y="446" fill="#999" font-size="10" font-family="monospace">cameras stay PARALLEL (no toe-in) - depth comes purely from the x offset</text>
+</svg>
--- /dev/null
+<svg viewBox="0 0 640 300" width="640" height="300" xmlns="http://www.w3.org/2000/svg">
+ <defs>
+ <filter id="glow">
+ <feGaussianBlur stdDeviation="1.5" result="blur"/>
+ <feMerge>
+ <feMergeNode in="blur"/>
+ <feMergeNode in="SourceGraphic"/>
+ </feMerge>
+ </filter>
+ </defs>
+
+ <!-- background -->
+ <rect width="640" height="300" fill="#061018"/>
+
+ <text x="320" y="30" fill="#40b0d0" font-size="15" font-family="monospace" text-anchor="middle" filter="url(#glow)">What changes per eye</text>
+
+ <!-- table-ish rows -->
+ <g font-family="monospace">
+ <!-- header -->
+ <text x="60" y="62" fill="#999" font-size="10">concern</text>
+ <text x="330" y="62" fill="#999" font-size="10">per-eye behavior</text>
+ <line x1="55" y1="70" x2="600" y2="70" stroke="#1a3a4a" stroke-width="1"/>
+
+ <text x="60" y="92" fill="#c05088" font-size="10">camera</text>
+ <text x="330" y="92" fill="#40b0d0" font-size="10">translation.x += ±IPD/2 (restored after the pass)</text>
+ <line x1="55" y1="100" x2="600" y2="100" stroke="#1a3a4a" stroke-width="0.5"/>
+
+ <text x="60" y="122" fill="#c05088" font-size="10">projection</text>
+ <text x="330" y="122" fill="#40b0d0" font-size="10">scale = eyeWidth/3; x += stereoViewportOffsetX</text>
+ <line x1="55" y1="130" x2="600" y2="130" stroke="#1a3a4a" stroke-width="0.5"/>
+
+ <text x="60" y="152" fill="#c05088" font-size="10">frustum culling</text>
+ <text x="330" y="152" fill="#40b0d0" font-size="10">built from stereoViewportWidth - narrower FOV per eye</text>
+ <line x1="55" y1="160" x2="600" y2="160" stroke="#1a3a4a" stroke-width="0.5"/>
+
+ <text x="60" y="182" fill="#c05088" font-size="10">painting</text>
+ <text x="330" y="182" fill="#40b0d0" font-size="10">clipped to [renderMinX, renderMaxX) = the eye's half</text>
+ <line x1="55" y1="190" x2="600" y2="190" stroke="#1a3a4a" stroke-width="0.5"/>
+
+ <text x="60" y="212" fill="#c05088" font-size="10">mouse picking</text>
+ <text x="330" y="212" fill="#40b0d0" font-size="10">hits combined only for the eye containing the cursor</text>
+ <line x1="55" y1="220" x2="600" y2="220" stroke="#1a3a4a" stroke-width="0.5"/>
+
+ <text x="60" y="242" fill="#c05088" font-size="10">HUD / overlays</text>
+ <text x="330" y="242" fill="#40b0d0" font-size="10">drawn once, spanning the full frame (zero disparity)</text>
+ </g>
+
+ <text x="60" y="282" fill="#999" font-size="9" font-family="monospace">everything else - geometry, textures, lightmaps, GI - is shared: the scene is identical, only the viewpoint moves</text>
+</svg>
--- /dev/null
+<svg viewBox="0 0 640 480" width="640" height="480" xmlns="http://www.w3.org/2000/svg">
+ <defs>
+ <filter id="glow">
+ <feGaussianBlur stdDeviation="2" result="blur"/>
+ <feMerge>
+ <feMergeNode in="blur"/>
+ <feMergeNode in="SourceGraphic"/>
+ </feMerge>
+ </filter>
+ <marker id="arrow" viewBox="0 0 10 10" refX="9" refY="5" markerWidth="7" markerHeight="7" orient="auto-start-reverse">
+ <path d="M 0 0 L 10 5 L 0 10 z" fill="#40b0d0"/>
+ </marker>
+ <marker id="arrowG" viewBox="0 0 10 10" refX="9" refY="5" markerWidth="7" markerHeight="7" orient="auto-start-reverse">
+ <path d="M 0 0 L 10 5 L 0 10 z" fill="#39FF14"/>
+ </marker>
+ </defs>
+
+ <!-- background -->
+ <rect width="640" height="480" fill="#061018"/>
+
+ <text x="320" y="32" fill="#40b0d0" font-size="17" font-family="monospace" text-anchor="middle" filter="url(#glow)">One frame = two passes</text>
+ <text x="320" y="50" fill="#999" font-size="10" font-family="monospace" text-anchor="middle">the triple-buffered pipeline runs the same phases twice, once per eye</text>
+
+ <!-- camera box -->
+ <rect x="230" y="70" width="180" height="44" rx="5" fill="rgba(176,144,32,0.08)" stroke="#b09020" stroke-width="1.5"/>
+ <text x="320" y="88" fill="#b09020" font-size="11" font-family="monospace" text-anchor="middle">camera</text>
+ <text x="320" y="104" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">translation.x nudged +/- IPD/2</text>
+
+ <!-- left pass lane -->
+ <rect x="40" y="150" width="250" height="60" rx="5" fill="rgba(57,255,20,0.06)" stroke="#39FF14" stroke-width="1.5" filter="url(#glow)"/>
+ <text x="165" y="172" fill="#39FF14" font-size="12" font-family="monospace" text-anchor="middle">pass LEFT</text>
+ <text x="165" y="188" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">transform → sort → tile-bin</text>
+ <text x="165" y="201" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">viewport [0, w/2)</text>
+
+ <!-- right pass lane -->
+ <rect x="350" y="150" width="250" height="60" rx="5" fill="rgba(64,176,208,0.06)" stroke="#40b0d0" stroke-width="1.5" filter="url(#glow)"/>
+ <text x="475" y="172" fill="#40b0d0" font-size="12" font-family="monospace" text-anchor="middle">pass RIGHT</text>
+ <text x="475" y="188" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">transform → sort → tile-bin</text>
+ <text x="475" y="201" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">viewport [w/2, w)</text>
+
+ <!-- arrows from camera -->
+ <line x1="285" y1="114" x2="180" y2="148" stroke="#39FF14" stroke-width="1.5" marker-end="url(#arrowG)"/>
+ <line x1="355" y1="114" x2="460" y2="148" stroke="#40b0d0" stroke-width="1.5" marker-end="url(#arrow)"/>
+
+ <!-- per-pass context note -->
+ <rect x="130" y="236" width="380" height="52" rx="5" fill="rgba(192,80,136,0.06)" stroke="#c05088" stroke-width="1.5"/>
+ <text x="320" y="256" fill="#c05088" font-size="10" font-family="monospace" text-anchor="middle">each pass owns a RenderingContext copy</text>
+ <text x="320" y="272" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">stereoEye, stereoViewportWidth/OffsetX, renderMinX..renderMaxX</text>
+
+ <line x1="165" y1="210" x2="250" y2="234" stroke="#39FF14" stroke-width="1.2" marker-end="url(#arrowG)"/>
+ <line x1="475" y1="210" x2="390" y2="234" stroke="#40b0d0" stroke-width="1.2" marker-end="url(#arrow)"/>
+
+ <!-- shared frame buffer -->
+ <rect x="70" y="330" width="500" height="80" rx="5" fill="rgba(255,255,255,0.03)" stroke="#b09020" stroke-width="1.5" filter="url(#glow)"/>
+ <rect x="70" y="330" width="250" height="80" fill="rgba(57,255,20,0.07)"/>
+ <rect x="320" y="330" width="250" height="80" fill="rgba(64,176,208,0.07)"/>
+ <line x1="320" y1="330" x2="320" y2="410" stroke="#c05088" stroke-width="2" stroke-dasharray="6 4"/>
+ <text x="195" y="365" fill="#39FF14" font-size="11" font-family="monospace" text-anchor="middle">left eye pixels</text>
+ <text x="195" y="382" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">painting clipped to left half</text>
+ <text x="445" y="365" fill="#40b0d0" font-size="11" font-family="monospace" text-anchor="middle">right eye pixels</text>
+ <text x="445" y="382" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">painting clipped to right half</text>
+ <text x="320" y="428" fill="#999" font-size="9" font-family="monospace" text-anchor="middle">ONE shared frame buffer → one blit to screen (side-by-side image)</text>
+
+ <line x1="250" y1="288" x2="195" y2="328" stroke="#39FF14" stroke-width="1.2" marker-end="url(#arrowG)"/>
+ <line x1="390" y1="288" x2="445" y2="328" stroke="#40b0d0" stroke-width="1.2" marker-end="url(#arrow)"/>
+
+ <text x="60" y="464" fill="#999" font-size="9" font-family="monospace">vertex buffers, aggregators and paint slots still cycle through 3 slots - the two passes overlap freely</text>
+</svg>
--- /dev/null
+#+SETUPFILE: ~/.emacs.d/org-styles/html/darksun.theme
+#+TITLE: Stereoscopic Rendering - Aukio 3D
+#+LANGUAGE: en
+#+LATEX_HEADER: \usepackage[margin=1.0in]{geometry}
+#+LATEX_HEADER: \usepackage{parskip}
+#+LATEX_HEADER: \setlength{\parindent}{15pt}
+#+LATEX_HEADER: \usepackage{palatino}
+#+LATEX_HEADER: \usepackage{charter}
+#+HTML_HEAD: <style type="text/css">body { max-width: 100%;}</style>
+
+[[file:../index.html#outline-container-understanding-3d-engine][<- Back to index]]
+
+* What stereo rendering adds
+:PROPERTIES:
+:CUSTOM_ID: what-stereo-adds
+:END:
+
+A single rendered image is flat: the brain infers depth only from
+monocular cues (occlusion, shading, perspective, motion parallax while
+you move). *Stereoscopic rendering* adds the strongest depth cue of
+all — /binocular disparity/: your two eyes see slightly different
+images, and the visual cortex turns the difference into a direct
+sensation of depth.
+
+Aukio 3D implements the simplest and most portable form: *side-by-side
+stereo*. Every frame renders the scene twice — once from the left eye
+position, once from the right — into the left and right halves of the
+same image. A VR headset, 3D TV, or a pair of XR glasses in
+side-by-side mode feeds each half to the corresponding eye, and the
+scene gains real volume.
+
+#+CAPTION: A side-by-side stereoscopic frame of the House demo, rendered headlessly with [[file:../index.org::#snapshot][the Snapshot tool]]. Left half: left eye. Right half: right eye. Compare the dark cube and the doorway between the halves — the horizontal shift is the disparity your brain reads as depth.
+[[file:stereo-side-by-side.png]]
+
+* The geometry: two parallel cameras
+:PROPERTIES:
+:CUSTOM_ID: geometry
+:END:
+
+The two eye cameras are identical to the mono camera except for one
+thing: the left eye's position is shifted by -IPD/2 and the right
+eye's by +IPD/2 along the *world* X axis (the offset is applied to the
+camera translation's =x= component directly, then restored). IPD
+(inter-pupillary distance) defaults to *6.5 world units* — the House
+demo treats 1 unit as 1 cm, and 6.5 cm is the median human IPD.
+
+Both cameras look in exactly the same direction (*parallel cameras*,
+no toe-in). Objects at different depths then land at different
+horizontal offsets between the two images — that offset is the
+disparity:
+
+#+CAPTION: Top-down view: the two eye positions and how a near and a far object project onto the screen plane. The near object separates much more between the eyes than the far one.
+[[file:Stereo geometry.svg]]
+
+- near object -> large disparity -> feels close,
+- far object -> small disparity -> feels far,
+- object at infinity -> zero disparity.
+
+Larger IPD exaggerates disparity (stronger but potentially straining
+depth); smaller IPD flattens the scene. =+=/=-= keys adjust it live in
+0.5-unit steps while stereo is active.
+
+* One frame = two passes
+:PROPERTIES:
+:CUSTOM_ID: two-passes
+:END:
+
+Stereo does not add a second pipeline — it runs the existing
+triple-buffered pipeline *twice per frame*. The render thread in
+=ViewPanel.renderFrame()= executes two render passes back to back:
+
+#+CAPTION: Per frame, the camera is nudged left, a full transform/sort/bin pass runs for the left viewport, then the camera is nudged right and a second pass runs for the right viewport. Both paint into one shared frame buffer, clipped to their half.
+[[file:Stereo pipeline.svg]]
+
+1. *Pass LEFT:* camera translation.x is temporarily decreased by
+ IPD/2, the scene is transformed, depth-sorted and tile-binned into a
+ per-pass =RenderingContext= copy whose viewport is the left half of
+ the frame (=[0, width/2)=), and the paint continuation is submitted
+ to the worker pool.
+2. *Pass RIGHT:* the same with +IPD/2 and the right viewport
+ (=[width/2, width)=). The camera offset is always restored in a
+ =finally= block, so the camera never drifts.
+3. The two paints write into *one shared frame buffer* — each clipped
+ to its half — and the completed side-by-side image is blitted to
+ the screen in one go.
+
+The triple-buffer machinery (3 vertex slots, 3 aggregator slots, 3
+framebuffers) does not change: a *pass* takes the slot =passCounter %
+3=, so left and right passes of the same frame simply occupy
+consecutive slots and overlap exactly like consecutive mono frames do.
+Workers flow from one pass's tiles straight into the next pass's tiles
+with no idle gap.
+
+* What adapts per eye
+:PROPERTIES:
+:CUSTOM_ID: per-eye
+:END:
+
+The scene itself — geometry, textures, lightmaps, global illumination
+— is shared and identical for both eyes. Only the *viewpoint* moves,
+so only view-dependent stages differ per pass:
+
+#+CAPTION: The per-eye surface area of the engine. Everything not listed here is eye-independent.
+[[file:Stereo per eye.svg]]
+
+- *Projection:* =Vertex= projects with =projectionScale = eyeWidth/3=
+ (per-eye horizontal FOV) and adds =stereoViewportOffsetX= so the
+ projected image lands in the correct half of the buffer. The same
+ offset is applied for near-plane-clip vertices created directly in
+ camera space.
+- *Frustum culling:* the frustum is rebuilt per pass from
+ =stereoViewportWidth=, so each eye culls against its own (narrower)
+ view volume — nothing leaks in from the other eye's half.
+- *Painting:* every painter clips X to =[renderMinX, renderMaxX)=,
+ which the pass set to its viewport. No eye can paint into the other
+ half, even if a polygon crosses the center line.
+- *Mouse picking:* in stereo each eye shows the same object at a
+ different screen X, so a hit can only be resolved against one eye.
+ =ViewPanel= combines mouse results only for the pass whose viewport
+ actually contains the cursor.
+- *HUD/overlays:* developer tools, crosshair and text are drawn once
+ over the finished frame, at zero disparity — they sit on the screen
+ surface, not in the world.
+
+* Enabling stereo
+:PROPERTIES:
+:CUSTOM_ID: enabling
+:END:
+
+#+BEGIN_SRC java
+ViewPanel viewPanel = ...;
+
+// Side-by-side stereo on:
+viewPanel.setStereoModeEnabled(true);
+
+// Optional: match the viewer (default 6.5 world units):
+viewPanel.setStereoIPD(6.5);
+#+END_SRC
+
+In the demos, *SHIFT+F11* toggles stereo and fullscreen together (XR
+glasses want both); plain *F11* remains fullscreen-only. With stereo
+active, *+* and *-* adjust the IPD in 0.5-unit steps (clamped at 0.5)
+so the viewer can tune comfort at runtime.
+
+#+CAPTION: The same scene rendered as a normal mono frame (for comparison with the pair above). Notice there is no horizontal offset to read depth from — the picture is flat.
+[[file:mono-comparison.png]]
+
+* Performance and limitations
+:PROPERTIES:
+:CUSTOM_ID: limitations
+:END:
+
+- Stereo *doubles the per-frame transform, sort and paint work* — two
+ full passes instead of one. The pipeline overlaps them the same way
+ it overlaps consecutive mono frames, so throughput drops less than
+ 2x on a multi-core machine, but expect a real cost.
+- Each eye gets *half the horizontal resolution* of the panel. On a
+ 1920x1080 fullscreen window each eye sees 960x1080 — pixels are
+ shared, not duplicated.
+- IPD is in *world units*: 6.5 only means "6.5 cm" if the scene is
+ modeled at 1 unit = 1 cm. In a scene with a different scale, divide
+ or multiply accordingly — or just tune with =+=/=-= until the depth
+ feels right.
+- The eye offset is applied along the *world X axis*, not the camera's
+ right vector: it is exactly correct when the camera faces along Z
+ (yaw = 0) and degrades as you turn — at yaw = 90° the eyes would be
+ offset front-to-back instead of side-to-side. For a fixed-viewing-
+ direction demo this is fine; a fully rotational stereo camera would
+ need to apply the IPD along the rotated right vector.
+- Side-by-side is a *display format*, not a headset driver: the engine
+ produces the image; an XR viewer, 3D TV or video player is
+ responsible for delivering the halves to the eyes.
+- Global illumination is unaffected: lightmaps live on the surfaces,
+ so both eyes sample the same converged lighting for free.
+
+* Related Classes
+:PROPERTIES:
+:CUSTOM_ID: related-classes
+:END:
+
+| Class | Role in stereo rendering |
+|----------------------+-----------------------------------------------------------------|
+| =ViewPanel= | owns stereoModeEnabled/stereoIPD; runs the two passes per frame |
+| =StereoEye= | NONE / LEFT / RIGHT tag carried by each pass context |
+| =RenderingContext= | per-eye viewport fields: stereoViewportWidth/OffsetX, renderMin/MaxX |
+| =Vertex= | per-eye projection: scale from eye width + viewport X offset |
+| =ShapeCollection= | rebuilds the frustum per pass from the eye's viewport width |
+| =InputManager= | SHIFT+F11 stereo toggle, +/- live IPD adjustment |
+
+[[file:../index.html#outline-container-understanding-3d-engine][Back to main documentation]]
--- /dev/null
+<svg viewBox="0 0 640 480" width="640" height="480" xmlns="http://www.w3.org/2000/svg">
+ <defs>
+ <marker id="arrow-green" viewBox="0 0 10 10" refX="10" refY="5"
+ markerWidth="8" markerHeight="8" orient="auto-start-reverse">
+ <path d="M 0 0 L 10 5 L 0 10 z" fill="#30a050"/>
+ </marker>
+ <marker id="arrow-red" viewBox="0 0 10 10" refX="10" refY="5"
+ markerWidth="8" markerHeight="8" orient="auto-start-reverse">
+ <path d="M 0 0 L 10 5 L 0 10 z" fill="rgba(208,64,64,0.5)"/>
+ </marker>
+ </defs>
+ <rect width="640" height="480" fill="#061018"/>
+
+ <!-- Green front-face triangle: V1=top, V2=bottom-left, V3=bottom-right -->
+ <polygon points="160,100 260,360 60,360" fill="rgba(48,160,80,0.15)" stroke="#30a050" stroke-width="3"/>
+ <!-- CCW arrow: arc from near V1, curves LEFT and DOWN toward V2 -->
+ <path d="M140,144 A 104,104 0 0,0 74,310" fill="none" stroke="#30a050" stroke-width="3" stroke-dasharray="8 4" marker-end="url(#arrow-green)"/>
+ <text x="68" y="240" fill="#30a050" font-size="20" font-weight="700" font-family="monospace">CCW</text>
+ <circle cx="160" cy="100" r="6" fill="#30a050"/>
+ <circle cx="60" cy="360" r="6" fill="#30a050"/>
+ <circle cx="260" cy="360" r="6" fill="#30a050"/>
+ <text x="156" y="88" fill="#aaa" font-size="18" font-family="monospace">V₁</text>
+ <text x="28" y="396" fill="#aaa" font-size="18" font-family="monospace">V₂</text>
+ <text x="264" y="396" fill="#aaa" font-size="18" font-family="monospace">V₃</text>
+ <text x="72" y="440" fill="#30a050" font-size="22" font-weight="700" font-family="monospace">FRONT FACE ✓</text>
+ <!-- Red back-face triangle -->
+ <polygon points="480,100 580,360 380,360" fill="rgba(208,64,64,0.06)" stroke="rgba(208,64,64,0.3)" stroke-width="3" stroke-dasharray="12 6"/>
+ <!-- CW arrow: arc from near V1, curves RIGHT and DOWN -->
+ <path d="M500,144 A 104,104 0 0,1 566,310" fill="none" stroke="rgba(208,64,64,0.5)" stroke-width="3" stroke-dasharray="8 4" marker-end="url(#arrow-red)"/>
+ <text x="536" y="240" fill="rgba(208,64,64,0.6)" font-size="20" font-weight="700" font-family="monospace">CW</text>
+ <line x1="456" y1="216" x2="504" y2="264" stroke="rgba(208,64,64,0.4)" stroke-width="6"/>
+ <line x1="504" y1="216" x2="456" y2="264" stroke="rgba(208,64,64,0.4)" stroke-width="6"/>
+ <text x="372" y="440" fill="rgba(208,64,64,0.7)" font-size="22" font-weight="700" font-family="monospace">BACK FACE ✗</text>
+ <text x="390" y="468" fill="#aaa" font-size="18" font-family="monospace">(culled — not drawn)</text>
+</svg>
--- /dev/null
+#!/bin/bash
+# export-docs.sh — export all org-mode documentation pages to HTML.
+#
+# Exports every Documentation/**/index.org (and Documentation/index.org)
+# with the darksun theme, using the user's Emacs configuration. Run from
+# anywhere:
+#
+# Documentation/export-docs.sh # export all pages
+# Documentation/export-docs.sh --check # export, then render every page with
+# # headless Chrome to /tmp/doc-check-*.png
+# # for visual inspection
+#
+# Requires: emacs (with ~/.emacs providing the org HTML setup),
+# google-chrome (only for --check).
+
+set -euo pipefail
+DOC_DIR="$(cd "$(dirname "$0")" && pwd)"
+
+mapfile -t PAGES < <(find "$DOC_DIR" -name index.org | sort)
+
+echo "Exporting ${#PAGES[@]} pages..."
+for page in "${PAGES[@]}"; do
+ rel="${page#"$DOC_DIR"/}"
+ if emacs --batch -l ~/.emacs --visit="$page" \
+ --funcall=org-html-export-to-html --kill 2>&1 \
+ | grep -qi "aborted\|unable to resolve link"; then
+ echo "FAIL $rel"
+ exit 1
+ fi
+ echo " ok $rel"
+done
+
+if [[ "${1:-}" == "--check" ]]; then
+ echo "Rendering pages for visual check..."
+ for page in "${PAGES[@]}"; do
+ rel="${page#"$DOC_DIR"/}"
+ html="${page%.org}.html"
+ out="/tmp/doc-check-$(echo "$rel" | tr '/ ' '__').png"
+ google-chrome --headless --disable-gpu --hide-scrollbars \
+ --virtual-time-budget=8000 --window-size=1100,2000 \
+ --screenshot="$out" "file://$html" 2>/dev/null
+ echo " shot $out"
+ done
+fi
+
+echo "Done."
--- /dev/null
+#+SETUPFILE: ~/.emacs.d/org-styles/html/darksun.theme
+#+TITLE: Aukio 3D - Realtime 3D engine
+#+LANGUAGE: en
+#+LATEX_HEADER: \usepackage[margin=1.0in]{geometry}
+#+LATEX_HEADER: \usepackage{parskip}
+#+LATEX_HEADER: \usepackage[none]{hyphenat}
+
+#+OPTIONS: H:20 num:20
+#+OPTIONS: author:nil
+
+#+HTML_HEAD: <link rel="stylesheet" href="style.css"/>
+
+* Introduction
+:PROPERTIES:
+:CUSTOM_ID: overview
+:ID: a31a1f4d-5368-4fd9-aaf8-fa6d81851187
+:END:
+
+[[file:Example.png]]
+
+*Aukio 3D* is a realtime 3D rendering engine written in pure Java. It
+runs entirely on the CPU — no GPU required, no OpenGL, no Vulkan, no
+native libraries. Just Java.
+
+The motivation is simple: GPU-based 3D is a minefield of accidental
+complexity. Drivers are buggy or missing entirely. Features you need
+aren't supported on your target hardware. You run out of GPU RAM. You
+wrestle with platform-specific interop layers, shader compilation
+quirks, and dependency hell. Every GPU API comes with its own
+ecosystem of pain — version mismatches, incomplete implementations,
+vendor-specific workarounds. I want a library that "just works".
+
+*Aukio 3D* takes a different path. By rendering everything in software
+on the CPU, the entire GPU problem space simply disappears. You add a
+Maven dependency, write some Java, and you have a 3D scene. It runs
+wherever Java runs.
+
+This approach is quite practical for many use-cases. Modern systems
+ship with many CPU cores, and those with unified memory architectures
+offer high bandwidth between CPU and RAM. Software rendering that once
+seemed wasteful is now a reasonable choice where you need good-enough
+performance without the overhead of a full GPU pipeline. Java's JIT
+compiler helps too, optimizing hot rendering paths at runtime.
+
+Beyond convenience, CPU rendering gives you complete control. You own
+every pixel. You can freely experiment with custom rendering
+algorithms, optimization strategies, and visual effects without being
+constrained by what a GPU API exposes. Instead of brute-forcing
+everything through a fixed GPU pipeline, you can implement clever,
+application-specific optimizations.
+
+*Aukio 3D* is part of the larger [[https://www3.svjatoslav.eu/projects/aukio/][Aukio project]], with the long-term goal
+of providing a platform for 3D user interfaces and interactive data
+visualization. It can also be used as a standalone 3D engine in any
+Java project. See the [[https://www3.svjatoslav.eu/projects/aukio-3d-demos/][demos]] for examples of what it can do today.
+
+*Major features:*
+** Global Illumination
+:PROPERTIES:
+:CUSTOM_ID: global-illumination
+:END:
+
+#+attr_html: :width 600px
+#+attr_latex: :width 600px
+[[file:Global illumination/Global illumination.png]]
+
+On top of flat shading, the engine computes progressive *global
+illumination* on background CPU threads: real shadows, smooth light
+falloff inside polygons (per-texel lightmaps), and indirect bounce
+light — while the render loop itself never traces a single ray.
+
+Read more about [[file:Global illumination/][global illumination]].
+
+** Side-by-side stereoscopic rendering support
+:PROPERTIES:
+:CUSTOM_ID: stereoscopic
+:END:
+
+#+attr_html: :width 600px
+#+attr_latex: :width 600px
+[[file:Stereoscopic rendering/stereo-side-by-side.png]]
+
+The engine can render every frame twice — once per eye — into the left
+and right halves of the same image, for XR glasses and 3D displays.
+The cameras stay parallel and are offset by a configurable IPD
+(inter-pupillary distance). Two render passes share one triple-buffered
+pipeline, each clipped to its half of the frame buffer; per-eye
+projection, frustum culling and mouse picking adapt automatically.
+
+See [[file:Stereoscopic%20rendering/][Stereoscopic rendering]] for the
+geometry, pipeline and tuning.
+
+** Constructive Solid Geometry
+:PROPERTIES:
+:CUSTOM_ID: constructive-solid-geometry
+:END:
+
+#+attr_html: :width 600px
+#+attr_latex: :width 600px
+[[file:CSG/CSG demo.png]]
+
+*Aukio 3D* allows performing boolean operations against geometry shapes.
+So one can subtract, unionize or intersect shapes.
+
+To understand CSG boolean operations, read more about [[file:CSG/][Constructive
+Solid Geometry]].
+
+** SDF textures for sharp text
+:PROPERTIES:
+:CUSTOM_ID: sdf-text
+:END:
+
+[[file:SDF textures/sdf-angled.png]]
+
+Text and vector-art surfaces do not store coverage; they store a
+*signed distance field* — per texel, the distance to the nearest glyph
+edge. The rasterizer re-derives coverage per screen pixel from that
+smooth field, so text stays sharp at any zoom and fades to clean gray
+under minification, all without a mipmap chain.
+
+See [[file:SDF%20textures/][SDF textures]] for the glyph pipeline, the
+render path, analytic minification and tuning knobs.
+
+* How take engine into use
+:PROPERTIES:
+:CUSTOM_ID: taking-engine-into-use
+:END:
+
+Add the *Aukio 3D* dependency to your Maven project:
+
+#+BEGIN_SRC xml
+<dependencies>
+ <dependency>
+ <groupId>eu.svjatoslav</groupId>
+ <artifactId>aukio-3d</artifactId>
+ <version>1.0.0</version>
+ </dependency>
+</dependencies>
+#+END_SRC
+
+Also add the repository (the library is not on Maven Central):
+
+#+BEGIN_SRC xml
+<repositories>
+ <repository>
+ <id>svjatoslav.eu</id>
+ <name>Svjatoslav repository</name>
+ <url>https://www3.svjatoslav.eu/maven/</url>
+ </repository>
+</repositories>
+#+END_SRC
+
+- Library requires Java 21 or newer.
+
+- Study the [[https://www3.svjatoslav.eu/projects/aukio-3d-demos/][demo applications]] for practical examples. Start with the
+ [[https://www3.svjatoslav.eu/projects/aukio-3d-demos/#minimal-example][minimal example]] to see the basic boilerplate needed to render a 3D
+ scene.
+
+- Study [[#understanding-3d-engine][how Aukio 3D engine works]].
+- Read online [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/][JavaDoc]].
+- See [[https://www3.svjatoslav.eu/projects/aukio-3d/graphs/][*Aukio 3D* class diagrams]]. (Diagrams were generated by using
+ [[https://www3.svjatoslav.eu/projects/javainspect/][JavaInspect]] utility)
+
+* Essential theory
+:PROPERTIES:
+:CUSTOM_ID: understanding-3d-engine
+:ID: 4b6c1355-0afe-40c6-86c3-14bf8a11a8d0
+:END:
+** Coordinate System (X, Y, Z)
+:PROPERTIES:
+:CUSTOM_ID: coordinate-system
+:END:
+
+#+INCLUDE: "Coordinate system.svg" export html
+
+*Aukio 3D* uses a **left-handed coordinate system with X pointing right
+and Y pointing down**, matching standard 2D screen coordinates. This
+coordinate system should feel intuitive for people with preexisting 2D
+graphics background.
+
+| Axis | Direction | Meaning |
+|------+------------------------------------+-------------------------------------------|
+| X | Horizontal, positive = RIGHT | Objects with larger X appear to the right |
+| Y | Vertical, positive = DOWN | Lower Y = higher visually (up) |
+| Z | Depth, positive = away from viewer | Negative Z = closer to camera |
+
+*Practical Examples*
+
+- A point at =(0, 0, 0)= is at the origin.
+- A point at =(100, 50, 200)= is: 100 units right, 50 units down
+ visually, 200 units away from the camera.
+- To place object A "above" object B, give A a **smaller Y value**
+ than B.
+
+Coordinates in this system are stored using the
+[[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/geometry/Point3D.html][Point3D]] class — a mutable container with public =x=, =y=, =z= fields
+supporting vector operations like distance, rotation, and translation.
+Vertices (see [[#vertex][below]]) are positioned within this coordinate system.
+
+The [[https://www3.svjatoslav.eu/projects/aukio-3d-demos/#coordinate-system][aukio-3d-demos]] project includes an interactive
+coordinate system reference showing X, Y, Z axes as colored arrows
+with a grid plane for spatial context.
+
+** Point3D and Vertex
+:PROPERTIES:
+:CUSTOM_ID: vertex
+:END:
+
+#+INCLUDE: "Point3D vertex.svg" export html
+
+Every 3D object is built from *vertices* — corner points that define
+the shape's geometry. A triangle has 3 vertices, a cube has 8, and
+complex meshes have thousands. The engine uses two related classes to
+represent points in 3D space, each serving a different purpose.
+
+
+
+*** Point3D — Raw Coordinates
+:PROPERTIES:
+:CUSTOM_ID: point3d-raw-coordinates
+:END:
+
+[[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/geometry/Point3D.html][Point3D]] is the fundamental coordinate type throughout the engine. It
+stores a position or vector with three public fields: =x=, =y=, =z=.
+The class provides vector math operations: distance calculation,
+rotation, translation, scaling, dot/cross products, and interpolation. Methods follow a fluent API convention where mutating
+operations (like =add=, =multiply=) return =this= for chaining, while
+non-mutating variants (like =withAdded=, =withMultiplied=) return new
+instances.
+
+Use =Point3D= for:
+- Storing positions, vectors, or any raw 3D coordinate
+- Distance and angle calculations between points
+- Vector math (dot product, cross product, normalization)
+- Rotating or translating positions before shape construction
+
+#+BEGIN_SRC java
+Point3D p1 = new Point3D(100, 50, 200);
+Point3D p2 = new Point3D(0, 0, 100);
+double distance = p1.getDistanceTo(p2); // Euclidean distance
+Point3D direction = p1.withSubtracted(p2).unit(); // New point: unit vector from p2 to p1
+p1.rotate(new Point3D(0,0,0), Math.PI/4, 0); // Rotate p1 in place, 45° in XZ plane
+#+END_SRC
+
+*** Vertex — Rendering-Ready Coordinates
+:PROPERTIES:
+:CUSTOM_ID: vertex-rendering-ready-coordinates
+:END:
+
+[[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/Vertex.html][Vertex]] wraps a =Point3D= and adds the coordinate spaces needed during
+rendering. As a shape transforms through the render pipeline, each
+vertex tracks its position in multiple spaces:
+
+| Field | Purpose |
+|------------------------+--------------------------------------------------------|
+| =coordinate= | Original position in local/model space |
+| =transformedCoordinate(ctx)= | Position relative to camera (after transform stack) |
+| =onScreenCoordinate(ctx)= | 2D screen pixels (after perspective projection) |
+| =textureCoordinate= | Optional UV coords in pixel units (not normalized) |
+| =normal= | Optional normal vector for CSG polygon splitting |
+
+=transformedCoordinate= and =onScreenCoordinate= are accessor methods,
+not plain fields: each vertex carries three slots for each, one per
+pipeline projection slot, and the accessor picks the slot of the
+context's current render pass. This is what lets the triple-buffered
+pipeline transform the next frame while previous frames are still
+being painted (see [[file:Rendering loop/index.org::#software-pipeline][software pipeline]]).
+
+During rendering, the vertex is transformed through all spaces: first
+applying the
+[[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/math/TransformStack.html][TransformStack]] to get the camera-relative coordinate, then
+projecting to 2D. Results are cached per frame per slot to avoid
+recomputing for vertices shared across multiple shapes.
+
+Use =Vertex= when:
+- Constructing triangles, polygons, or textured shapes
+- Your geometry needs texture UV coordinates
+- You're performing CSG boolean operations (requires =normal=)
+
+#+BEGIN_SRC java
+// Create a textured triangle (texture coordinates use pixel units)
+// For a 256x256 texture: (0,0)=top-left, (256,256)=bottom-right
+Vertex v1 = new Vertex(new Point3D(0, 0, 100), new Point2D(0, 0));
+Vertex v2 = new Vertex(new Point3D(100, 0, 100), new Point2D(256, 0));
+Vertex v3 = new Vertex(new Point3D(50, 100, 100), new Point2D(128, 256));
+TexturedTriangle triangle = new TexturedTriangle(v1, v2, v3, texture);
+#+END_SRC
+
+*** When to Use Each
+:PROPERTIES:
+:CUSTOM_ID: when-to-use-each
+:END:
+
+| Use Point3D | Use Vertex |
+|--------------------------------------+-----------------------------------------------|
+| Positioning shapes, cameras, lights | Building triangles and polygons |
+| Vector math (distances, directions) | Texture-mapped geometry |
+| Rotating or translating positions | CSG operations |
+| Temporary calculations | Shapes that render through transform pipeline |
+
+For simple shapes without textures, you can pass raw =Point3D=
+coordinates directly to constructors — the shape will internally wrap
+them in =Vertex= objects. The [[#coordinate-system][coordinate system]] above defines the
+meaning of all =x=, =y=, =z= values in both classes.
+
+** Edge
+:PROPERTIES:
+:CUSTOM_ID: edge
+:END:
+
+#+INCLUDE: "Edge.svg" export html
+
+An *edge* is a straight line segment connecting two [[#vertex][vertices]]. Edges
+form the wireframe skeleton of a 3D model — the structural framework
+visible when surfaces are not rendered. A triangle has 3 edges, a cube
+has 12 edges, and complex meshes have thousands.
+
+In *Aukio 3D*, the [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/basic/line/Line.html][Line]] class implements edges as renderable shapes. Each
+Line connects two [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/Vertex.html][Vertex]] endpoints and stores two properties: a
+[[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/basic/line/Line.html#width][width]] in world units (adjusted for perspective during rendering) and a
+[[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/basic/line/Line.html#color][color]] with alpha transparency. The rendering algorithm switches
+between two modes based on the projected screen width: thin lines below
+the threshold are drawn as single pixels with alpha-adjusted coloring,
+while thicker lines are rendered as filled rectangles with perspective-correct
+edge fading using four [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/basic/line/LineInterpolator.html][LineInterpolator]] scanline boundaries.
+
+Wireframe shapes are composite objects built from multiple Line instances.
+For example, [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/composite/wireframe/WireframeBox.html][WireframeBox]] creates 12 Line objects — four edges parallel to
+each axis — using a [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/basic/line/LineAppearance.html][LineAppearance]] factory to ensure consistent styling across
+all edges. The [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/composite/wireframe/WireframeCube.html][WireframeCube]] convenience subclass provides a center-point
+constructor. See the [[https://www3.svjatoslav.eu/projects/aukio-3d-demos/#shape-gallery][Shape Gallery demo]] for a visual comparison of
+wireframe (edges only) versus solid polygon (surfaces with lighting)
+rendering modes.
+
+** Face (Triangle)
+:PROPERTIES:
+:CUSTOM_ID: face-triangle
+:END:
+
+#+INCLUDE: "Face triangle.svg" export html
+
+A *face* is a flat surface enclosed by edges — the visible skin of a 3D
+object. While faces can theoretically have any number of sides, 3D
+engines standardize on *triangles* because three points always define a
+flat plane. A quad (4 vertices) or pentagon (5 vertices) might be
+non-planar depending on vertex positions, causing rendering artifacts.
+Triangles avoid this problem entirely.
+
+*** SolidPolygon — Solid-Color Faces
+:PROPERTIES:
+:CUSTOM_ID: solidpolygon-solid-color-faces
+:END:
+
+[[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/basic/solidpolygon/SolidPolygon.html][SolidPolygon]] is the primary face type, supporting any number of vertices
+(3 or more). Triangles render directly via scanline rasterization.
+N-vertex polygons (quads, pentagons, etc.) are triangulated using fan
+decomposition — a quad becomes 2 triangles, a pentagon 3 — but only
+when the polygon lives inside an
+[[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/composite/base/AbstractCompositeShape.html][AbstractCompositeShape]]
+(the scene graph root is one): the composite triangulates while
+building its render list. A standalone SolidPolygon with more than 3
+vertices cannot be painted directly and throws IllegalStateException.
+
+Each SolidPolygon stores a single fill color with optional alpha
+transparency. When shading is enabled, the lighting manager computes
+the polygon's illumination once during the transform phase, then
+applies the shaded color during painting. Backface culling (see
+[[#winding-order-backface-culling][Winding Order & Backface Culling]]) can be enabled per-polygon, or
+applied recursively to an entire composite shape via
+[[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/composite/base/AbstractCompositeShape.html#setBackfaceCulling(boolean)][AbstractCompositeShape.setBackfaceCulling(true)]] — this propagates the
+setting to all SolidPolygon and TexturedTriangle sub-shapes, including
+nested composites.
+
+#+BEGIN_SRC java
+// Create a red triangle
+SolidPolygon triangle = SolidPolygon.triangle(
+ new Point3D(0, 0, 100),
+ new Point3D(50, 0, 100),
+ new Point3D(25, 50, 100),
+ Color.RED
+);
+
+// Create a blue quad (internally triangulated)
+SolidPolygon quad = SolidPolygon.quad(
+ new Point3D(-50, -50, 100),
+ new Point3D(50, -50, 100),
+ new Point3D(50, 50, 100),
+ new Point3D(-50, 50, 100),
+ Color.BLUE
+);
+
+// Enable lighting and culling for a closed mesh
+quad.setShadingEnabled(true);
+quad.setBackfaceCulling(true);
+
+// Add to the scene — the root composite triangulates the quad
+viewPanel.getRootShapeCollection().addShape(quad);
+#+END_SRC
+
+*** TexturedTriangle — UV-Mapped Faces
+:PROPERTIES:
+:CUSTOM_ID: texturedtriangle-uv-mapped-faces
+:END:
+
+[[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/basic/texturedpolygon/TexturedTriangle.html][TexturedTriangle]] renders faces with image textures mapped via UV
+coordinates. Each of the three [[#vertex][vertices]] stores a =textureCoordinate=
+(a [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/geometry/Point2D.html][Point2D]] with U and V values in *pixel units* matching the texture
+dimensions). For a 256×256 texture, coordinates range from (0,0) at the
+top-left corner to (256,256) at the bottom-right. During rasterization, the
+engine interpolates these UV coordinates across the triangle's surface,
+sampling the texture at each pixel. When mipmaps are used, the [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/texture/TextureBitmap.html#multiplicationFactor][multiplicationFactor]]
+scales coordinates to match the selected mipmap resolution.
+
+The texture system supports mipmaps — pre-scaled versions of the texture
+selected based on the triangle's screen size to reduce aliasing artifacts
+on distant surfaces. Texture coordinates are mapped with
+perspective-correct interpolation inside the scanline rasterizer, so
+large triangles at steep angles render without distortion — see the
+[[file:Perspective correct textures/][perspective-correct textures]] page.
+
+#+BEGIN_SRC java
+// Create a 256x256 texture
+Texture texture = new Texture(256, 256, 2); // width, height, maxUpscale
+
+// Create a textured triangle with UV coordinates in pixel units
+Vertex v1 = new Vertex(new Point3D(0, 0, 100), new Point2D(0, 0)); // top-left
+Vertex v2 = new Vertex(new Point3D(100, 0, 100), new Point2D(256, 0)); // top-right
+Vertex v3 = new Vertex(new Point3D(50, 100, 100), new Point2D(128, 256)); // bottom-center
+
+TexturedTriangle triangle = new TexturedTriangle(v1, v2, v3, texture);
+triangle.setBackfaceCulling(true);
+#+END_SRC
+
+Both SolidPolygon and TexturedTriangle extend
+[[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/AbstractCoordinateShape.html][AbstractCoordinateShape]], which handles vertex transformation and depth
+sorting. See the [[https://www3.svjatoslav.eu/projects/aukio-3d-demos/#shape-gallery][Shape Gallery demo]] for a visual comparison of solid
+versus textured polygon rendering.
+
+** Normal Vector
+:PROPERTIES:
+:CUSTOM_ID: normal-vector
+:END:
+
+#+INCLUDE: "Normal vector.svg" export html
+
+A *normal* is a vector perpendicular to a surface. It tells the
+renderer which direction a face is pointing. Normals are critical for
+*lighting* — the angle between the light direction and the normal
+determines how bright a surface appears.
+
+**Use cases:**
+
+| Use case | API | Computation | Location |
+|----------------------+----------------------------------------------+----------------------------+-------------------|
+| BSP/CSG operations | [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/basic/solidpolygon/SolidPolygon.html#getPlane()][SolidPolygon.getPlane()]] → [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/composite/base/Plane.html#normal][Plane.normal]] | Lazy-cached once | =Plane= |
+| Per-frame shading | [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/composite/base/Plane.html#computeNormal()][Plane.computeNormal()]] → =cachedNormal= field | Recomputed every frame | =SolidPolygon= |
+| Lighting calculation | [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/lighting/LightingManager.html#computeLighting()][LightingManager.computeLighting()]] | Uses normal via =dot(L,N)= | =LightingManager= |
+
+**Implementation notes:**
+- [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/composite/base/Plane.html#computeNormal()][Plane.computeNormal()]]: shared zero-allocation helper for computing normals from three points
+- [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/composite/base/Plane.html][Plane]]: stores normals in Hesse normal form (normal + distance) for BSP spatial partitioning
+- [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/Vertex.html#normal][Vertex.normal]]: optional field for CSG polygon splitting (not used for rendering)
+
+** Mesh
+:PROPERTIES:
+:CUSTOM_ID: mesh
+:END:
+
+#+INCLUDE: "Mesh.svg" export html
+
+A *mesh* is a collection of vertices, edges, and faces that together
+define the shape of a 3D object. Even curved surfaces like spheres are
+approximated by many small triangles — more triangles means a smoother
+appearance. A cube has 8 vertices forming 12 triangular faces, while a
+smooth sphere requires hundreds or thousands of triangles depending on
+the desired quality.
+
+In *Aukio 3D*, meshes are built through composition rather than
+monolithic vertex/index buffers. The [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/AbstractCoordinateShape.html][AbstractCoordinateShape]] class is
+the foundation for primitive shapes — each instance stores its own
+[[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/AbstractCoordinateShape.html#vertices][List<Vertex>]] directly. This includes [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/basic/solidpolygon/SolidPolygon.html][SolidPolygon]] (N-vertex
+convex polygons, not limited to triangles), [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/basic/texturedpolygon/TexturedTriangle.html][TexturedTriangle]]
+(UV-mapped triangles), and [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/basic/line/Line.html][Line]] (wireframe edges). The
+[[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/composite/base/AbstractCompositeShape.html][AbstractCompositeShape]] class groups multiple shapes into a single
+object with its own position, rotation, and transform — useful for
+complex models that move or rotate together.
+
+Complex meshes are constructed procedurally by adding primitive shapes
+during initialization. For example, [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/composite/solid/SolidPolygonSphere.html][SolidPolygonSphere]] generates
+triangles using a latitude-longitude grid: with 16 segments, it
+creates 960 SolidPolygon triangles by looping through
+rings and sectors, calling [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/composite/base/AbstractCompositeShape.html#addShape(eu.svjatoslav.aukio.e3d.renderer.raster.shapes.AbstractShape)][addShape()]] for each. The generic
+[[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/composite/solid/SolidPolygonMesh.html][SolidPolygonMesh]] accepts any list of triangles, allowing custom
+geometry from procedural generation or external sources.
+
+During rendering, several automatic optimizations occur. N-vertex
+polygons (quads, pentagons, etc.) are triangulated using fan
+triangulation inside the composite's render-list builder, converting
+an N-vertex polygon into N-2 triangles. Textured triangles render with
+perspective-correct texture mapping (see [[file:Perspective correct textures/][perspective-correct textures]]).
+Composites perform view frustum culling to skip rendering when entirely
+off-screen. Sub-shapes can be organized into named groups via [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/composite/base/SubShape.html][SubShape]]
+wrappers, allowing [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/composite/base/AbstractCompositeShape.html#showGroup(java.lang.String)][showGroup()]] and [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/composite/base/AbstractCompositeShape.html#hideGroup(java.lang.String)][hideGroup()]] to toggle visibility of
+entire sections. Composite shapes also support CSG boolean operations
+— see the [[file:CSG/][Constructive Solid Geometry]] documentation for union,
+subtract, and intersect operations.
+
+The [[https://www3.svjatoslav.eu/projects/aukio-3d-demos/#shape-gallery][Shape Gallery demo]] showcases all primitive shapes available in
+*Aukio 3D*, rendered in both wireframe mode (edges only via
+[[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/composite/wireframe/WireframeBox.html][WireframeBox]] and similar) and solid polygon mode (filled surfaces with
+dynamic lighting).
+
+** Working with Colors
+:PROPERTIES:
+:CUSTOM_ID: working-with-colors
+:ID: f2c9642a-a093-444f-8992-76c97ff28c16
+:END:
+
+Aukio 3D uses its own [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/Color.html][Color class]] instead of [[https://docs.oracle.com/en/java/javase/21/docs/api/java.desktop/java/awt/Color.html][java.awt.Color]]. This
+custom implementation is designed specifically for the engine's
+software rasterizer, where avoiding object allocation during rendering
+is critical for performance. When rendering thousands of polygons per
+frame, creating new Color instances for each one would generate
+excessive garbage and trigger frequent garbage collection
+pauses. Instead, the engine's Color class uses mutable fields that can
+be reused across frames.
+
+The class stores RGBA components as public integer fields in the range
+0–255. This format matches the engine's pixel buffer layout and avoids
+costly float-to-int conversions during rasterization. The [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/Color.html#r][r]], [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/Color.html#g][g]], [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/Color.html#b][b]], and
+[[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/Color.html#a][a]] fields are accessible directly, allowing lighting calculations and
+alpha blending to modify colors in-place without allocating new
+objects. For example, the [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/basic/solidpolygon/SolidPolygon.html][SolidPolygon]] class maintains a reusable
+[[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/basic/solidpolygon/SolidPolygon.html][shadedColor]] field that gets updated during each frame's lighting
+calculation instead of creating a new Color instance per polygon.
+
+Color provides several constructors for different input formats. The
+most common approach is using hex strings via [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/Color.html#hex(java.lang.String)][Color.hex(String)]] or the
+[[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/Color.html#%3Cinit%3E(java.lang.String)][String constructor]], which support formats like ="F80"= (3-digit RGB),
+="FF8800"= (6-digit RGB), ="F808"= (4-digit RGBA), and ="FF8800CC"=
+(8-digit RGBA). You can also create colors from integer RGBA
+components (0–255) using [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/Color.html#%3Cinit%3E(int,int,int,int)][new Color(r, g, b, a)]], from floating-point
+components (0.0–1.0) via [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/Color.html#%3Cinit%3E(double,double,double,double)][new Color(double r, double g, double b,
+double a)]], or from a packed RGB integer like =0xFF8800= using [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/Color.html#%3Cinit%3E(int)][new
+Color(int rgb)]]. The class also provides predefined constants for
+common colors: [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/Color.html#RED][Color.RED]], [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/Color.html#GREEN][Color.GREEN]], [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/Color.html#BLUE][Color.BLUE]], [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/Color.html#YELLOW][Color.YELLOW]],
+[[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/Color.html#CYAN][Color.CYAN]], [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/Color.html#MAGENTA][Color.MAGENTA]], [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/Color.html#WHITE][Color.WHITE]], [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/Color.html#BLACK][Color.BLACK]], and
+[[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/Color.html#TRANSPARENT][Color.TRANSPARENT]].
+
+The [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/Color.html#set(int,int,int,int)][set(int r, int g, int b, int a)]] method modifies a Color in-place
+and returns =this= for method chaining, which is essential for
+performance during rendering. For example, the [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/lighting/LightingManager.html][LightingManager]]
+calculates lighting contributions from all light sources and stores
+the final shaded color directly into a reusable Color instance via
+=set()=, avoiding any allocation. The [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/Color.html#toAwtColor()][toAwtColor()]] method converts a
+Aukio 3D Color to a java.awt.Color when needed for Java2D graphics
+operations, caching the result to avoid repeated conversion. The
+[[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/Color.html#toInt()][toInt()]] method packs the color into an ARGB integer suitable for the
+engine's pixel buffer, used during rasterization to write pixels
+directly.
+
+#+BEGIN_SRC java
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+import static eu.svjatoslav.aukio.e3d.renderer.raster.Color.hex;
+
+// Using predefined color constants
+Color red = Color.RED;
+Color transparent = Color.TRANSPARENT;
+
+// Create from hex string (recommended for clarity)
+Color orange = hex("FF8800"); // RGB, fully opaque
+Color semiTransparent = hex("FF880080"); // RGBA, 50% transparent
+
+// Create from integer components (0-255)
+Color custom = new Color(255, 128, 64, 200);
+
+// Create from packed RGB integer
+Color packed = new Color(0xFF8800);
+
+// Modify existing color in-place (no allocation)
+Color reusable = new Color();
+reusable.set(100, 200, 50, 255);
+
+// Convert to AWT color for Java2D operations
+java.awt.Color awtColor = custom.toAwtColor();
+
+// Use in lighting calculations (LightingManager modifies in-place)
+// See the Shading & Lighting documentation for details
+#+END_SRC
+
+The alpha component controls transparency during rendering. A value of
+0 makes the color fully transparent, while 255 makes it fully
+opaque. The rasterizer implements alpha blending during the paint
+phase: when drawing a semi-transparent pixel, the engine blends the
+source color with the existing background pixel proportionally based
+on the alpha value. The [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/texture/TextureBitmap.html#drawPixel(int,int\[\],int)][TextureBitmap.drawPixel()]] method handles this
+blending, multiplying source colors by alpha and background colors by
+=(255 - alpha)=, then combining them. You can test whether a color is
+fully transparent using [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/Color.html#isTransparent()][isTransparent()]], which returns true when alpha
+equals zero.
+
+For lighting calculations, the [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/lighting/LightSource.html][LightSource]] class uses Color to
+represent the color and intensity of emitted light. Multiple light
+sources contribute to the final shaded color of each polygon, as
+described in the [[file:Shading/index.org::#shading-lighting][Shading & Lighting]] documentation. The [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/lighting/LightingManager.html#setAmbientLight(eu.svjatoslav.aukio.e3d.renderer.raster.Color)][ambient light]]
+provides base illumination that affects all surfaces equally,
+regardless of orientation. Colors are also used for wireframe
+rendering via the [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/basic/line/Line.html][Line]] class, where the color field determines the
+line's appearance.
+
+** Shading & Lighting
+:PROPERTIES:
+:CUSTOM_ID: shading-lighting
+:END:
+
+#+attr_html: :width 600px
+#+attr_latex: :width 600px
+[[file:Shading/Shaded%20sphere.png]]
+
+
+*Aukio 3D* implements *flat shading* — one normal per polygon,
+computed from the first three vertices. Each polygon receives a single
+color based on its orientation relative to light sources.
+
+To understand lighting and shading, read more about [[file:Shading/][shading & lighting]].
+
+* 3D engine internals
+:PROPERTIES:
+:CUSTOM_ID: engine-internals
+:END:
+** Main render loop
+:PROPERTIES:
+:CUSTOM_ID: main-render-loop
+:END:
+
+The rendering loop is the heart of the engine, continuously generating
+frames at a target rate (typically 60 FPS). Each frame transforms 3D
+shapes through a multi-stage pipeline before displaying them on screen.
+
+#+INCLUDE: "Rendering loop/Render pipeline.svg" export html
+
+The render loop runs on a dedicated background daemon thread managed by
+[[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/gui/ViewPanel.html][ViewPanel]], which can optionally sleep between frames to maintain a
+target FPS or run unlimited for benchmarking.
+
+For a detailed walkthrough of each phase with diagrams and code
+examples, see the dedicated page: [[file:Rendering loop/][Rendering loop]].
+
+** Near-Plane Clipping
+:PROPERTIES:
+:CUSTOM_ID: near-plane-clipping
+:END:
+
+Individual polygons that straddle the camera's near plane are not
+dropped wholesale: the vertex loop is clipped against the plane, new
+intersection vertices are generated with 3D-interpolated UVs and
+normals, and the clipped polygon — a triangle can become a quad,
+painted as a triangle fan — renders normally. Only polygons entirely
+behind the near plane are culled. This keeps floor and wall tiles
+visible when the camera brushes against them.
+
+#+INCLUDE: "Near plane clip/Near plane straddle.svg" export html
+
+Read more about [[file:Near plane clip/][near-plane clipping]].
+
+** Depth buffer
+:PROPERTIES:
+:CUSTOM_ID: depth-buffer
+:END:
+
+Visibility is resolved per pixel by a depth buffer: every triangle
+interpolates =1/z= across its spans and wins a pixel only where it is
+nearer than the surface already there. Opaque geometry — textured
+triangles, solid polygons — paints front-to-back with depth writes;
+translucent geometry paints back-to-front with depth tests but no
+writes, so it never occludes. Lines and billboards stay painter-ordered
+overlays by design.
+
+See [[file:Depth%20buffer/][Depth buffer]] for the full treatment.
+
+** Frustum & View Frustum Culling
+:PROPERTIES:
+:CUSTOM_ID: frustum-view-frustum-culling
+:END:
+
+*Aukio 3D* implements view frustum culling.
+
+#+INCLUDE: "Frustum culling/Frustum diagram.svg" export html
+
+To understand frustum culling and object-level visibility
+optimization, read more about [[file:Frustum culling/][frustum & view frustum culling.]]
+
+** Winding Order & Backface Culling
+:PROPERTIES:
+:CUSTOM_ID: winding-order-backface-culling
+:END:
+
+#+INCLUDE: "Winding order.svg" export html
+
+The order in which a triangle's vertices are listed determines its
+*winding order*. In *Aukio 3D*, screen coordinates have Y-axis pointing
+*down*, which inverts the apparent winding direction compared to
+standard mathematical convention (Y-up). *Counter-clockwise (CCW)* in
+screen space means front-facing. *Backface culling* skips rendering
+triangles that face away from the camera — a major performance
+optimization.
+
+- CCW winding (in screen space) → front face (visible)
+- CW winding (in screen space) → back face (culled)
+- When viewing a polygon from outside: define vertices in *counter-clockwise* order as seen from the camera
+- Saves ~50% of triangle rendering
+- Implementation uses signed area: =signedArea < 0= means front-facing
+ (in Y-down screen coordinates, negative signed area corresponds to
+ visually CCW winding)
+
+In *Aukio 3D*, backface culling is *optional* and disabled by default. Enable it per-shape:
+- [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/basic/solidpolygon/SolidPolygon.html#setBackfaceCulling(boolean)][SolidPolygon.setBackfaceCulling(true)]]
+- [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/basic/texturedpolygon/TexturedTriangle.html#setBackfaceCulling(boolean)][TexturedTriangle.setBackfaceCulling(true)]]
+- [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/composite/base/AbstractCompositeShape.html#setBackfaceCulling(boolean)][AbstractCompositeShape.setBackfaceCulling(true)]] (applies to all
+ sub-shapes)
+
+See the [[https://www3.svjatoslav.eu/projects/aukio-3d-demos/#winding-order][Winding Order demo]] for an interactive visualization.
+
+** Perspective correct textures
+:PROPERTIES:
+:CUSTOM_ID: perspective-correct-textures
+:END:
+
+#+attr_html: :class responsive-img
+#+attr_latex: :width 1000px
+[[file:Perspective correct textures/Affine distortion.png]]
+
+*Aukio 3D* tries to do perspective-correct texture rendering. Read more
+about [[file:Perspective correct textures/][perspective-correct texture implementation]].
+
+* Developer tools
+:PROPERTIES:
+:CUSTOM_ID: developer-tools
+:ID: 8c5e2a1f-9d3b-4f6a-b8e7-1c4d5f7a9b2e
+:END:
+
+Press *F12* anywhere in the application to open the Developer Tools
+panel:
+
+#+attr_html: :class responsive-img
+#+attr_latex: :width 1000px
+[[file:Developer tools/Developer tools.png]]
+
+This debugging interface helps you understand what the engine is doing
+internally and diagnose rendering issues. Pressing F12 again closes
+the panel.
+
+** Diagnostic toggles
+:PROPERTIES:
+:CUSTOM_ID: diagnostic-toggles
+:END:
+
+*** Show polygon borders
+:PROPERTIES:
+:CUSTOM_ID: show-polygon-borders
+:END:
+
+When enabled, each [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/shapes/basic/texturedpolygon/TexturedTriangle.html][TexturedTriangle]] draws yellow outlines around its
+three edges after rendering its texture content. This overlays the
+triangle mesh onto the final image:
+
+#+attr_html: :class responsive-img
+[[file:Developer tools/Render polygon borders.png]]
+
+Use this visualization when investigating:
+
+- Mesh structure: see the actual triangles as the rasterizer receives
+ them
+- Geometry bugs: spot T-junction gaps and overlapping geometry
+- Texture distortion: compare triangle shapes against visible warping
+
+*** Render alternate segments (overdraw debug)
+:PROPERTIES:
+:CUSTOM_ID: render-alternate-segments
+:END:
+
+Renders only even-numbered paint tiles while leaving odd-numbered ones
+black. (The screen is divided into a grid of rectangular tiles for
+parallel rendering — see [[file:Rendering loop/index.org::#phase-4-clear-paint-tiles][the rendering loop documentation]].
+"Segments" is the older name for tiles.)
+
+#+attr_html: :class responsive-img
+[[file:Developer tools/Render alternative segments.png]]
+
+This toggle helps detect overdraw: threads writing outside their
+allocated tile. If you see rendering artifacts in the black tiles, a
+paint task is writing pixels outside its assigned area — a clear sign
+of a bug.
+
+*** Show segment boundaries
+:PROPERTIES:
+:CUSTOM_ID: show-segment-boundaries
+:END:
+
+Draws red lines along the paint tile boundaries, making it easy to see
+exactly where each tile's rendered area begins and ends. In stereo
+mode each eye's viewport gets its own grid:
+
+#+attr_html: :class responsive-img
+[[file:Developer tools/Show segment boundaries.png]]
+
+Useful for:
+
+- Verifying the tile grid division
+- Debugging tile-boundary rendering issues (e.g. clipped text or
+ missing slivers at tile edges)
+- Understanding the parallel rendering architecture visually
+
+** Camera position
+:PROPERTIES:
+:CUSTOM_ID: camera-position
+:END:
+
+Displays the current camera coordinates and orientation in real-time:
+
+| Parameter | Description |
+|-----------+------------------------------------------|
+| x, y, z | Camera position in 3D world space |
+| yaw | Rotation around the Y axis (left/right) |
+| pitch | Rotation around the X axis (up/down) |
+| roll | Rotation around the Z axis (tilt) |
+
+The *Copy* button copies the full camera position string to the
+clipboard in a format ready to paste into bug reports or configuration
+files.
+
+Use this for:
+- Reporting exact camera positions when filing bugs
+- Saving interesting viewpoints for later reference
+- Understanding camera movement during navigation
+- Sharing specific views with other developers
+
+Example copied format:
+#+BEGIN_EXAMPLE
+500.00, -300.00, -800.00, 0.60, -0.50, -0.00
+#+END_EXAMPLE
+
+The six numbers map 1:1 onto
+[[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/math/Transform.html#set(double,double,double,double,double,double)][Transform.set(x, y, z, yaw, pitch, roll)]],
+so a copied viewpoint can be restored at startup — this is how the
+demo applications freeze a good camera position into code:
+
+#+BEGIN_SRC java
+// Camera position captured via Developer Tools -> Copy
+viewPanel.getCamera().getTransform().set(
+ 130.66, -65.49, -248.18, // x, y, z
+ -0.06, -0.36, -0.00); // yaw, pitch, roll
+#+END_SRC
+
+** Frustum culling statistics
+:PROPERTIES:
+:CUSTOM_ID: frustum-culling-statistics
+:END:
+
+Shows real-time statistics about composite shape frustum culling
+efficiency (see the dedicated [[file:Frustum culling/][frustum culling]] page for how
+culling itself works):
+
+| Statistic | Description |
+|-----------+----------------------------------------------------------|
+| Total | Number of composite shapes tested against the frustum |
+| Culled | Number of composites rejected (outside view frustum) |
+| Culled % | Percentage of composites that were culled (0-100%) |
+
+*How to interpret the numbers:*
+
+- *High cull % (60-90%)*: Excellent — most objects are being correctly culled
+- *Medium cull % (20-60%)*: Moderate — some optimization benefit
+- *Low cull % (0-20%)*: Limited benefit — either all objects are visible, or scene needs restructuring
+
+*Example:*
+#+BEGIN_EXAMPLE
+Total: 473 Culled: 425 (89.9%)
+#+END_EXAMPLE
+
+This means 473 composite shapes were tested, 425 were outside the view
+and skipped entirely, and only 48 composites (with all their children)
+actually needed to be rendered. This is excellent culling efficiency.
+
+The statistics update every 200ms while the panel is open. Note that
+the root composite is never frustum-tested (it's always rendered), so
+the "Total" count excludes it.
+
+** Render threads
+:PROPERTIES:
+:CUSTOM_ID: render-threads
+:END:
+
+Shows the number of active render threads versus available CPU cores.
+The engine defaults to 75% of available threads (at most cores − 1, so
+one thread always stays free for the rest of the system). The count is
+changeable at runtime via [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/gui/ViewPanel.html#setNumRenderThreads(int)][ViewPanel.setNumRenderThreads(int)]];
+the worker pool is recreated lazily on the next frame.
+
+** Frame rate
+:PROPERTIES:
+:CUSTOM_ID: frame-rate
+:END:
+
+Shows the current target FPS and the measured production rate (frames
+completed per second, averaged over a ~500 ms window). The measured
+number counts produced frames regardless of how quickly the display
+path presents them — see [[file:Rendering loop/index.org::#frame-rate-control][frame rate control]].
+
+The *Unlock FPS* toggle switches to unlimited (benchmark) mode: the
+engine renders continuously as fast as possible, even when the scene
+is static. Toggling off restores the previously locked target rate.
+
+** Thread activity timeline
+:PROPERTIES:
+:CUSTOM_ID: thread-activity-timeline
+:END:
+
+A per-thread occupancy view — the software-renderer equivalent of a
+GPU frame profiler. Each thread gets a row (the render thread and
+present thread on top, then one row per worker), time runs along the X
+axis, and each colored block is one recorded work interval. Idle time
+is black.
+
+#+attr_html: :class responsive-img
+[[file:Developer tools/Thread timeline.png]]
+
+Press *Record* to start capturing. The colors encode both the task
+kind and which frame the task belongs to — transform, paint, and
+binning come in three frame-parity variants (f0/f1/f2), so you can see
+up to three frames in flight simultaneously. Additional colors mark
+render-thread orchestration, blocked time, blits, and the sort/drain
+sub-phases.
+
+Navigation: mouse wheel scrolls, Ctrl+wheel zooms, and a scrollbar
+moves along the captured range.
+
+The legend colors, exactly as the timeline paints them:
+
+| Color | Legend label | What it shows |
+|-------+--------------+---------------|
+| @@html:<span style="display:inline-block;width:2.2em;height:0.9em;background:#2ECC40;border:1px solid #444;vertical-align:middle"></span>@@ =#2ECC40= | =transform f0= | Vertex transform chunk task, frame slot 0 |
+| @@html:<span style="display:inline-block;width:2.2em;height:0.9em;background:#B8D900;border:1px solid #444;vertical-align:middle"></span>@@ =#B8D900= | =transform f1= | Vertex transform chunk task, frame slot 1 |
+| @@html:<span style="display:inline-block;width:2.2em;height:0.9em;background:#6B8E23;border:1px solid #444;vertical-align:middle"></span>@@ =#6B8E23= | =transform f2= | Vertex transform chunk task, frame slot 2 |
+| @@html:<span style="display:inline-block;width:2.2em;height:0.9em;background:#0074D9;border:1px solid #444;vertical-align:middle"></span>@@ =#0074D9= | =paint f0= | Paint tile task (clear + rasterize one tile), frame slot 0 |
+| @@html:<span style="display:inline-block;width:2.2em;height:0.9em;background:#F012BE;border:1px solid #444;vertical-align:middle"></span>@@ =#F012BE= | =paint f1= | Paint tile task, frame slot 1 |
+| @@html:<span style="display:inline-block;width:2.2em;height:0.9em;background:#B10DC9;border:1px solid #444;vertical-align:middle"></span>@@ =#B10DC9= | =paint f2= | Paint tile task, frame slot 2 |
+| @@html:<span style="display:inline-block;width:2.2em;height:0.9em;background:#39CCCC;border:1px solid #444;vertical-align:middle"></span>@@ =#39CCCC= | =bin f0= | Tile binning task (assign sorted shapes to tiles), frame slot 0 |
+| @@html:<span style="display:inline-block;width:2.2em;height:0.9em;background:#008B8B;border:1px solid #444;vertical-align:middle"></span>@@ =#008B8B= | =bin f1= | Tile binning task, frame slot 1 |
+| @@html:<span style="display:inline-block;width:2.2em;height:0.9em;background:#007070;border:1px solid #444;vertical-align:middle"></span>@@ =#007070= | =bin f2= | Tile binning task, frame slot 2 |
+| @@html:<span style="display:inline-block;width:2.2em;height:0.9em;background:#A0A0A0;border:1px solid #444;vertical-align:middle"></span>@@ =#A0A0A0= | =render serial= | Render thread orchestration: tree walk and pass submission |
+| @@html:<span style="display:inline-block;width:2.2em;height:0.9em;background:#8B0000;border:1px solid #444;vertical-align:middle"></span>@@ =#8B0000= | =blocked= | Render thread waiting for an older paint pass or the present gate |
+| @@html:<span style="display:inline-block;width:2.2em;height:0.9em;background:#FFFFFF;border:1px solid #444;vertical-align:middle"></span>@@ =#FFFFFF= | =blit= | Present thread copying a finished frame to the screen |
+| @@html:<span style="display:inline-block;width:2.2em;height:0.9em;background:#FF851B;border:1px solid #444;vertical-align:middle"></span>@@ =#FF851B= | =sort+bin= | A pass's async continuation as a whole: drain, sort, bin, submit paint |
+| @@html:<span style="display:inline-block;width:2.2em;height:0.9em;background:#8B4513;border:1px solid #444;vertical-align:middle"></span>@@ =#8B4513= | =drain= | Continuation sub-phase: await and merge parallel transform chunks |
+| @@html:<span style="display:inline-block;width:2.2em;height:0.9em;background:#FFD700;border:1px solid #444;vertical-align:middle"></span>@@ =#FFD700= | =sort= | Continuation sub-phase: depth sort of the pass's shapes |
+
+The f0/f1/f2 suffixes are the frame's projection slot (frame number
+modulo 3) — the triple-buffering from the [[file:Rendering loop/index.org::#software-pipeline][software pipeline]].
+When the pipeline is healthy you see interleaved colors from two or
+three frames on the worker rows at once: paint tasks of an older frame
+overlapping transform and binning of the newer one. Wide =blocked=
+spans on the render row, or worker rows with black gaps, mean the
+pipeline is starved rather than busy.
+
+Recording is cheap but not free (~100 ns per task; a single volatile
+read when disabled), so leave it off during benchmarking runs. The
+captured intervals live in a fixed-size ring buffer — long recordings
+keep only the most recent history.
+
+What to look for:
+
+- *Solidly packed worker rows* mean the pipeline is keeping all cores
+ busy — the design goal (see [[file:Rendering loop/index.org::#software-pipeline][software pipeline]])
+- *Long "blocked" spans on the render row* mean the render thread is
+ waiting for paint passes — workers are the bottleneck
+- *Long "blit" spans on the present row* mean the display path
+ (X server) is the bottleneck; excess frames are being dropped from
+ the presentation mailbox
+
+** Live log viewer
+:PROPERTIES:
+:CUSTOM_ID: live-log-viewer
+:END:
+
+The scrollable text area shows captured debug output in real-time:
+- Green text on black background for readability
+- Auto-scrolls to show latest entries
+- Updates every 200ms while panel is open
+- Captures logs even when panel is closed (replays when reopened)
+
+Use the *Clear Logs* button to reset the log buffer for fresh
+diagnostic captures.
+
+** Headless & agentic tooling
+:PROPERTIES:
+:CUSTOM_ID: headless-agentic
+:END:
+
+For windowless rendering, pixel assertions, golden-image regression
+tests and scene dumps — built for automated verification and AI agents —
+see [[#agentic-development][agentic development tools]].
+
+* Agentic development
+:PROPERTIES:
+:CUSTOM_ID: agentic-development
+:END:
+
+*Aukio 3D* provides good support for automated AI coding agents
+(for example OpenCode, Hermes Agent, etc..).
+
+Thanks to facilities is =eu.svjatoslav.aukio.e3d.headless= package, an
+AI agent can render any scene from any pose, assert what got painted,
+compare against committed reference images, and dump the full scene
+state for a bug report — all without a window, a display, or the
+render thread.
+
+** One pipeline, two drivers
+:PROPERTIES:
+:CUSTOM_ID: one-pipeline
+:END:
+
+The key design decision: the headless path drives *the very same
+transform → sort → paint pipeline* the on-screen ViewPanel
+uses. Nothing is reimplemented, so a passing headless test proves the
+real render works, and a bug reproduced headlessly is the real bug.
+
+#+INCLUDE: "Agentic development/Headless lanes.svg" export html
+
+Making this possible required three small engine changes:
+
+- ~ShapeCollection.transformShapes(Camera, RenderingContext)~ — the
+ transform phase now accepts a camera directly; the ViewPanel variant
+ just forwards its camera. Headless code never touches Swing.
+- ~RenderingContext.getImage()~ — hands out the backing BufferedImage
+ the rasterizer paints into.
+- ~GlobalIllumination.isRunning()~ / ~isConverged()~ /
+ ~getWorkItemCount()~ — GI state became inspectable.
+
+** Snapshot: render without a window
+:PROPERTIES:
+:CUSTOM_ID: snapshot
+:END:
+
+#+BEGIN_SRC java
+import eu.svjatoslav.aukio.e3d.headless.Snapshot;
+
+ShapeCollection scene = new ShapeCollection();
+scene.addShape(myShape);
+LightingManager lighting = new LightingManager();
+lighting.setAmbientLight(Color.hex("181818"));
+
+// One call: build context, transform, sort, paint, return the image.
+BufferedImage image = Snapshot.render(scene, lighting,
+ "290.31, -35.59, -2.10, -0.58, -0.15, 0.0", 640, 480);
+Snapshot.save(image, "/tmp/snapshot.png");
+#+END_SRC
+
+The pose string is the *same "x, y, z, yaw, pitch, roll" format the
+demos print* and users quote in bug reports — paste the pose, reproduce
+the exact view. ~Snapshot.cameraFromPose()~ and ~Snapshot.poseString()~
+convert in both directions.
+
+For tests that need to detect *unpainted* pixels (holes), the
+~renderInto()~ variant fills the background with a caller-chosen
+sentinel color first, so "nothing was painted here" is unambiguous even
+in a pitch-black scene:
+
+#+BEGIN_SRC java
+RenderingContext ctx = new RenderingContext(640, 480, 1);
+ctx.lightingManager = lighting;
+Snapshot.renderInto(scene, camera, ctx, 0x00010203); // sentinel
+#+END_SRC
+
+A real headless render — the House demo from a bug-report pose:
+
+#+attr_html: :class responsive-img
+#+attr_latex: :width 640px
+[[file:Agentic development/snapshot-example.png]]
+
+** PixelAssertions: did this region get painted?
+:PROPERTIES:
+:CUSTOM_ID: pixel-assertions
+:END:
+
+The recurring debugging question — "did the floor actually render, or
+did clipping eat it?" — becomes a library call:
+
+#+BEGIN_SRC java
+import eu.svjatoslav.aukio.e3d.headless.PixelAssertions;
+
+// Fraction of a relative rectangle still equal to the background:
+double holes = PixelAssertions.unpaintedFraction(image, 0,
+ 0.15, 0.45, 0.85, 1.0); // lower-center band
+if (holes > 0.05)
+ throw new AssertionError("floor has holes: " + holes);
+
+long red = PixelAssertions.countColor(image, 0xFF0000); // flat-color tests
+String grid = PixelAssertions.dumpPixelGrid(image, 320, 240, 3, 8); // hex dump
+#+END_SRC
+
+#+INCLUDE: "Agentic development/Pixel assertion.svg" export html
+
+** GoldenImage: compare against a reference
+:PROPERTIES:
+:CUSTOM_ID: golden-image
+:END:
+
+A pixel counts as different when any RGB channel drifts more than a
+per-channel tolerance; the comparison fails when the fraction of
+differing pixels exceeds a threshold. Deterministic flat-shaded renders
+can use tight tolerances (4, 0.005); noisier paths relax them.
+
+#+BEGIN_SRC java
+import eu.svjatoslav.aukio.e3d.headless.GoldenImage;
+
+GoldenImage.Result r = GoldenImage.compare(actual,
+ new File("goldens/house-flat.png"), 4, 0.005);
+if (!r.passed)
+ GoldenImage.saveDiff(actual, goldenFile, "/tmp/diff.png"); // red = differs
+#+END_SRC
+
+#+INCLUDE: "Agentic development/Golden workflow.svg" export html
+
+There is also a CLI for shell scripts — exit 0 = match, 1 = differ:
+
+#+BEGIN_SRC bash
+java eu.svjatoslav.aukio.e3d.headless.GoldenImage actual.png golden.png 4 0.005
+#+END_SRC
+
+A real diff: the house rendered with the living-room lamp removed,
+compared against the golden. The red region is exactly the room that
+lost its light:
+
+#+attr_html: :class responsive-img
+#+attr_latex: :width 640px
+[[file:Agentic development/diff-example.png]]
+
+** SceneDump: the reproducible bug report
+:PROPERTIES:
+:CUSTOM_ID: scene-dump
+:END:
+
+One call produces everything needed to reproduce what a frame shows:
+
+#+BEGIN_SRC java
+System.out.println(SceneDump.dump(scene, lighting, camera, gi));
+#+END_SRC
+
+#+BEGIN_EXAMPLE
+== SceneDump ==
+shapes: 5 top-level, 546 queued for rendering
+lights: 4 (ambient #181818)
+ [0] pos=(-800.0, -240.0, 0.0) color=FFD890 intensity=6.0
+ [1] pos=(0.0, -240.0, 0.0) color=D8E4FF intensity=5.0
+ [2] pos=(800.0, -240.0, 0.0) color=FFB060 intensity=6.0
+ [3] pos=(250.0, -60.0, -250.0) color=60FF90 intensity=2.0
+camera: 290.31, -35.59, -2.10, -0.58, -0.15, -0.00
+GI: running, 152034 work items, converged
+#+END_EXAMPLE
+
+The camera line is a pose string — it feeds straight back into
+~Snapshot.render()~.
+
+** HouseGoldens: ready-made regression tests
+:PROPERTIES:
+:CUSTOM_ID: house-goldens
+:END:
+
+The aukio-3d-demos repo contains a working example of all of the above:
+~eu.svjatoslav.aukio.e3d.examples.goldens.HouseGoldens~ renders the
+House demo at two poses (the default view and the near-plane straddle
+bug pose), compares both against committed goldens, and independently
+asserts the floor has no holes.
+
+#+BEGIN_SRC bash
+cd aukio-3d-demos
+mvn clean package
+mvn -q dependency:build-classpath -Dmdep.outputFile=cp.txt
+java -cp "target/classes:$(cat cp.txt)" \
+ eu.svjatoslav.aukio.e3d.examples.goldens.HouseGoldens # verify
+java -cp "target/classes:$(cat cp.txt)" \
+ eu.svjatoslav.aukio.e3d.examples.goldens.HouseGoldens --update # regenerate goldens
+#+END_SRC
+
+Exit code 0 = all pass, 1 = any mismatch (with a diff PNG in /tmp).
+Demos that want the same treatment expose their scene construction:
+~HouseDemo.buildHouse()~, ~addFurniture()~ and ~addLights()~ are public
+for exactly this reason.
+
+** export-docs.sh: regenerate the documentation
+:PROPERTIES:
+:CUSTOM_ID: export-docs
+:END:
+
+All engine documentation (the pages you are reading) lives as org-mode
+files under =doc/=. One script exports every page to HTML with the
+darksun theme:
+
+#+BEGIN_SRC bash
+doc/export-docs.sh # export all pages
+doc/export-docs.sh --check # + render every page with headless Chrome
+ # to /tmp/doc-check-*.png for visual review
+#+END_SRC
+
+The =--check= mode is how an agent verifies its own documentation: SVG
+label collisions, broken image links and table breakage all show up in
+the rendered screenshots.
+
+** A typical agent session
+:PROPERTIES:
+:CUSTOM_ID: typical-session
+:END:
+
+#+BEGIN_EXAMPLE
+1. Reproduce: Snapshot.render(scene, lighting, bugReportPose, 640, 480)
+2. Inspect: SceneDump.dump(...) + view the PNG
+3. Fix the engine
+4. Verify: PixelAssertions.unpaintedFraction(...) == 0
+5. Regression: HouseGoldens (must stay ALL PASS)
+6. Document: edit doc pages, export-docs.sh --check, review shots
+#+END_EXAMPLE
+
+** Related Classes
+:PROPERTIES:
+:CUSTOM_ID: related-classes
+:END:
+
+| Class | Purpose |
+|-----------------+----------------------------------------------------|
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/headless/Snapshot.html][Snapshot]] | Windowless render facade + pose string conversion |
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/headless/PixelAssertions.html][PixelAssertions]] | Painted-region / color-count / hex-grid assertions |
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/headless/GoldenImage.html][GoldenImage]] | Golden-PNG comparison, diff writer, CLI |
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/headless/SceneDump.html][SceneDump]] | Scene state as a reproducible text block |
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/ShapeCollection.html][ShapeCollection]] | ~transformShapes(Camera, ...)~ headless overload |
+| [[https://www3.svjatoslav.eu/projects/aukio-3d/apidocs/eu/svjatoslav/aukio/e3d/renderer/raster/RenderingContext.html][RenderingContext]] | ~getImage()~ exposes the painted frame |
+
+* Source code
+:PROPERTIES:
+:CUSTOM_ID: source-code
+:ID: 978b7ea2-e246-45d0-be76-4d561308e9f3
+:END:
+
+*This program is free software: released under Creative Commons Zero
+(CC0) license*
+
+*Program author:*
+- Svjatoslav Agejenko
+- Homepage: https://svjatoslav.eu
+- Email: mailto://svjatoslav@svjatoslav.eu
+- See also: [[https://www.svjatoslav.eu/projects/][Other software projects hosted at svjatoslav.eu]]
+
+*Getting the source code:*
+- [[https://www2.svjatoslav.eu/gitweb/?p=aukio-3d.git;a=snapshot;h=HEAD;sf=tgz][Download latest source code snapshot in TAR GZ format]]
+- [[https://www2.svjatoslav.eu/gitweb/?p=aukio-3d.git;a=summary][Browse Git repository online]]
+- Clone Git repository using command:
+ : git clone https://www3.svjatoslav.eu/git/aukio-3d.git
--- /dev/null
+# Architecture & maintainability review — aukio-3d
+
+Scope: 152 main-source files, ~31.7k LOC at `/home/n0/workspace/Aukio/aukio-3d`.
+Read fully: ViewPanel, TexturedTriangle, AbstractCompositeShape, OctreeVolume, RenderAggregator,
+RenderingContext, AbstractCoordinateShape, ShapeCollection, SolidPolygon, LineInterpolator,
+PolygonBorderInterpolator, SegmentRenderingContext, AbstractShape; skimmed the rest.
+Dead-code claims verified by grep across aukio-3d (main+test), aukio-3d-demos, aukio,
+aukio-environment-fo4 (no reflection usage found in consumers; demos touch 64 engine classes,
+aukio 24, fo4 17 — the API surface is genuinely exercised).
+
+---
+
+## [HIGH] 1. ViewPanel is a god class — 10 distinct responsibilities
+
+`gui/ViewPanel.java` (1611 lines). Responsibilities, with evidence:
+
+1. AWT/Swing integration — `getPreferredSize/getMinimumSize/getMaximumSize` (420-432),
+ `paint/update` overrides (537-543), `initializeCanvas` (545-556), `addNotify` (558-562),
+ `ensureBufferStrategy` (564-594).
+2. Frame-loop & FPS pacing — `renderLoop` (1444-1456), `maintainTargetFps` (1464-1485),
+ `ensureThatViewIsUpToDate` (1494-1521), `noteFrameBlitted` (987-1001).
+3. Pipeline scheduling (transform/sort/bin/paint triple-buffered passes) — `renderFrame`
+ (598-652), `transformPass` (1094-1132), `submitPaintPass` (1146-1273),
+ `flushPendingPaint` (800-877), `flushCompletedPasses` (889-901), `PendingPaint`/`PresentJob`
+ (240-266).
+4. Presentation thread + mailbox — `presentFrame` (671-684), `presentLoop` (703-742),
+ `blitFrame` (744-791), mailbox fields (198-208), `PRESENT_RATE_LIMIT_FPS` (223-224).
+5. Stereo configuration & eye-offset math — fields (1029-1039), `transformPass` IPD offset
+ (1100-1104), stereo accessors (1046-1080).
+6. Thread-pool lifecycle — `getOrCreateTransformExecutor` (1295-1321),
+ `defaultRenderThreadCount` (1284-1287), plus the dead `renderExecutor` machinery
+ (see finding 7).
+7. Input device hot-plug — `initializeHeadTracking` (1346-1352), `initializeSpaceMouse`
+ (1360-1366).
+8. Developer tools integration — `showDeveloperToolsPanel` (516-535), segment-boundary
+ overlay drawn inline into the framebuffer (849-869).
+9. Lighting & GI lifecycle — `lightingManager` (145), `enableGlobalIllumination` (490-510).
+10. Raster helpers that belong to the renderer — `clearSegmentPixels` (911-926),
+ `combineMouseResults` (928-941).
+
+Refactor sketch: extract (a) `PipelineScheduler` owning renderFrame/transformPass/
+submitPaintPass/flush* + pendingPaints/passCounter/frameContexts (~550 lines), (b)
+`FramePresenter` owning mailbox/presentLoop/blitFrame/PresentJob (~150 lines), (c)
+`DeviceHotplug` for headtrack+spacemouse init/stop (~60 lines). ViewPanel keeps AWT glue,
+public API delegating to the three. The four participants communicate through
+RenderingContext fields that already exist.
+
+Risk: HIGH but contained to the engine — no rasterizer math touched, so golden pixels are
+untouched by construction. The risk is concurrency regression in the pipeline itself; mitigated
+by the `aukio3d.pipeline=false` kill switch (232-233) and the existing
+ParallelTransformTest/SegmentBinningTest. Move code verbatim first (no logic edits),
+verify with the demos' HouseGoldens + Fo4Shot runs.
+
+## [HIGH] 2. Package structure is fictional — total cycle, renderer↔gui inverted
+
+The import graph over top-level packages contains every possible cycle: gui↔renderer,
+geometry↔renderer, geometry↔gui, math↔gui, math↔geometry (computed over all 152 files).
+
+Root cause: the renderer's core types live in `gui`:
+- `gui/RenderingContext.java`, `gui/SegmentRenderingContext.java`, `gui/HiZPyramid.java`,
+ `gui/CullingStatistics.java`, `gui/ThreadActivityRecorder.java`.
+- 15 renderer files import `gui.*`, e.g. `renderer/raster/RenderAggregator.java:7`,
+ `renderer/raster/ShapeCollection.java:9-12` (imports gui.CullingStatistics, gui.Camera,
+ **gui.ViewPanel** — the renderer depends on the AWT Canvas),
+ `renderer/raster/shapes/basic/texturedpolygon/TriangleMeshBlock.java:6` (gui.HiZPyramid).
+- 5 gui files import renderer (ViewPanel:21-23, RenderingContext:11+18, GuiComponent:14-16,
+ LookAndFeel:7, TextEditComponent:13) → direct gui↔renderer cycle.
+- geometry depends upward: `geometry/BspTree.java:7` and `geometry/Plane.java:8` import
+ renderer...SolidPolygon; `geometry/Frustum.java:7` imports gui.Camera;
+ `geometry/Point3D.java:7` imports renderer.octree.IntegerPoint (for one convenience
+ constructor, Point3D.java:121).
+- `math/Vertex.java:9` imports gui.RenderingContext.
+
+Refactor sketch (mechanical, move-only): relocate RenderingContext, SegmentRenderingContext,
+HiZPyramid, CullingStatistics, ThreadActivityRecorder, StereoEye to `renderer.raster` (or a new
+`renderer.core`); move `gui.Camera`+`gui.ViewSpaceTracker` to geometry/math (Camera is pure
+transform state). Break geometry→renderer by moving BspTree to
+renderer...shapes.basic.solidpolygon (it stores SolidPolygon) or abstracting its element type.
+Fix Point3D→IntegerPoint by moving that constructor to IntegerPoint or a small adapter.
+ShapeCollection's ViewPanel dependency is only `viewPanel.getCamera()`
+(ShapeCollection.java:302-305) — the Camera overload already exists (314), so the ViewPanel
+overload is a convenience that could delegate from gui side or take a Camera.
+After moves, the intended order math ← geometry ← renderer ← gui/headless becomes real.
+
+Risk: LOW for correctness (no code changes, only moves + import updates), MEDIUM for consumers:
+three downstream repos must update imports. Public API breakage is the cost; do it in one sweep
+with a consumer-side sed. Golden tests unaffected (no FP code moves between classes in a way
+that changes execution order — class relocation has no runtime effect).
+
+## [HIGH] 3. Verified dead code — 6 classes + 2 fields (~340 lines)
+
+Grepped simple-name references across engine main+test and all three consumer repos:
+
+- `geometry/Circle.java` (30 LOC) — no references anywhere.
+- `gui/ViewUpdateTimerTask.java` (31 LOC) — no references; legacy of the pre-render-thread
+ design (its `run()` calls the now-package-private `ensureThatViewIsUpToDate`).
+- `gui/humaninput/Connexion3D.java` (48 LOC) — standalone /dev/hidraw experiment with its own
+ `main()`; superseded by `gui/spacemouse/SpaceNavigatorHid`.
+- `renderer/octree/raytracer/RayHit.java` (56 LOC) — unreferenced even inside the raytracer.
+- `renderer/raster/shapes/composite/solid/SolidPolygonMesh.java` (60 LOC) — unreferenced.
+- `renderer/raster/shapes/composite/wireframe/WireframeDrawing.java` (75 LOC) — unreferenced.
+- `ViewPanel.renderExecutor` + `ensureExecutorMatchesThreadCount()` (ViewPanel.java:121,
+ 1327-1339, 1406): created, resized, shut down — but **never used to submit a single task**;
+ `submitPaintPass` uses `getOrCreateTransformExecutor()` (1155). Legacy of the pre-ForkJoinPool
+ design. ~35 dead lines including the eager `Executors.newFixedThreadPool(...)` allocation at
+ construction time (121) — a real thread pool allocated and thrown away per ViewPanel.
+- `ViewPanel.renderFrameCount` (596, incremented at 607): static, write-only, never read.
+
+Refactor sketch: delete all of the above.
+Risk: ZERO for the classes/fields (no references exist, no reflection in consumers). Keep a
+note that Connexion3D's main() is a hardware experiment if the maintainer wants it archived.
+
+## [HIGH] 4. AbstractCompositeShape carries an embeddable CSG engine + parallel-transform machinery
+
+`renderer/raster/shapes/composite/base/AbstractCompositeShape.java` (1295 lines). Responsibilities:
+
+1. Sub-shape registry + group visibility (88-133, 179-195, 335-377, 756-764).
+2. Render-list caching & triangulation (775-821, 886-910).
+3. CSG boolean engine (~240 lines, fully self-contained): `extractSolidPolygons` (304-315),
+ `union` (549-574), `subtract` (597-631), `intersect` (654-683), `clonePolygons` (694-700),
+ `replaceSolidPolygons` (709-725), `mergeNonPolygonChildrenFrom` (735-748).
+4. Bounding-box aggregation (230-280).
+5. Frustum culling inline in `transform` (912-997; AABB corner transform at 929-971).
+6. Parallel-transform machinery (~280 lines): weight-cache fields (1026-1077),
+ `getTransformWeight` (1095-1120), `shouldForkTransform` (1132-1140),
+ `transformChildrenParallel` (1192-1275), constants (1003-1020, 1147).
+7. Bulk property fan-out via instanceof chains — 8 sites: `setColor` (397-409),
+ `setShadingEnabled` (494-504), `setBackfaceCulling` (514-526),
+ `setMouseInteractionController` (422-432), plus 254, 308-311, 478, 791-807, 851-856.
+
+Also: `transformChildrenParallel(…, aggregator, …)` takes a **dead parameter** — its own
+javadoc admits it (1187-1190: "unused in the parallel path"), and the body never uses it.
+
+Refactor sketch: (a) move the CSG block to a new `Csg` utility class in the same package —
+all methods take/return `List<SolidPolygon>` plus the registry mutations already isolated in
+`replaceSolidPolygons`/`mergeNonPolygonChildrenFrom`; AbstractCompositeShape keeps three
+one-line delegating methods for API compatibility. (b) Extract the weight/fork machinery into
+`ParallelTransformPlanner` (fields + getTransformWeight + shouldForkTransform + chunking),
+leaving `transform()` as orchestration. (c) Drop the dead `aggregator` parameter from
+`transformChildrenParallel`. Result: ~1295 → ~700 lines.
+
+Risk: LOW-MEDIUM. CSG is call-graph-isolated (only BspTree + registry), no FP-order-sensitive
+output (CSG is geometry, not rasterization — pixel risk none; geometry-identical because the
+code moves verbatim). The parallel planner touches concurrency — move verbatim, keep field
+semantics; verified by ParallelTransformTest.
+
+## [MEDIUM] 5. RenderAggregator: cohesive, but three separable machines
+
+`renderer/raster/RenderAggregator.java` (861 lines). Responsibilities:
+
+1. Shape queue + merge: `queueShapeForRendering` (703-706), `mergeFrom` (716-720),
+ `mergeAllParallel` (734-795), `reset` (831-838).
+2. Sorting with three strategies (~210 lines): `tryRadixSort` (187-228), `parallelMergeSort`
+ (235-280), `runSortTasks` (283-308), `mergeRuns` (311-322), `awaitAll` (324-334), driver
+ `sort` (131-174).
+3. Tile binning CSR (~280 lines): fields (400-418), `matchingBinIndex` (427-439), `matchAxis`
+ (452-463), `binForTiles` (500-523), `buildBins` (543-593), `binPhase` (596-634),
+ `binRangeCsr` (642-683).
+4. Two-pass paint orchestration: `paintSorted` (353-366), `paintRange` (370-397).
+
+Refactor sketch: extract `ShapeSortMachine` (sort strategies + scratch arrays) and
+`TileBinMachine` (CSR fields + build/match), aggregator keeps queue + paint and holds one of
+each. Also drop `implements Serializable` on the comparator (844) — nothing serializes it.
+Note the sort order contract (Z desc, shapeId asc) is the bit-exactness backbone for
+binning/paint; extraction must move code verbatim.
+
+Risk: LOW (pure control flow, no FP math; order preserved by construction). Verified by
+SegmentBinningTest + HouseGoldens.
+
+## [MEDIUM] 6. Rasterizer duplication: 7 span writers, 3 interpolator classes, 2 blend formulas
+
+Interpolators — three classes with byte-identical cores:
+`LineInterpolator` (solidpolygon), `PolygonBorderInterpolator` (texturedpolygon),
+`PerspectiveBorderInterpolator` (texturedpolygon). Identical: `containsY` (LineInterpolator:
+84-88 = PolygonBorderInterpolator: 85-89 = PerspectiveBorderInterpolator: 101-105), the
+`getX` formula (`round(p1.x + (width*(y-p1.y))/height)`, LineInterpolator:100-105 vs
+PolygonBorderInterpolator:129-134), `setPointsZW` (LineInterpolator:130-134 =
+PolygonBorderInterpolator:182-186 = PerspectiveBorderInterpolator:137+).
+
+Span/line writers — 7 sites: TexturedTriangle's `drawHorizontalLinePerspectiveZ` (223-405),
+`drawHorizontalLineSdf` (968-1086), `drawHorizontalLinePerspectiveSdf` (1093-1263),
+`drawHorizontalLineZ` (1312-1429); SolidPolygon's `drawHorizontalLine` (305-386); Line's two
+single-pixel painters (180-233, 242-298). Within TexturedTriangle alone:
+- the SDF bilinear-fetch + coverage block is byte-identical twice (1023-1066 vs 1197-1240, ~45 lines);
+- the adaptive-interval ladder is byte-identical twice (322-335 vs 1163-1177);
+- the edge-pair Y-scan loop appears 4× (698-708, 927-937, 950-960, 1293-1303), a 5th in
+ SolidPolygon (456-468);
+- the yTop/yBottom clamp block appears 2× in-file (467-486 vs 596-615), a 3rd in SolidPolygon
+ (425-440);
+- the swap-left/right + clamp preamble appears 4× (239-260, 986-994, 1117-1127, 1327-1346).
+
+Two *different* alpha-blend approximations exist: SolidPolygon/Line use
+`((dest*bgAlpha) + src*alpha) >> 8` (SolidPolygon:376-378, Line:223-225, 289-291);
+TexturedTriangle uses `dest + ((alpha*(src-dest) - dest) >> 8)` (386-388 and 3 more sites).
+**They are not pixel-equivalent** — unifying span writers would change golden output.
+
+Refactor sketch (ordered by safety):
+(a) SAFE: unify the three interpolators into one `EdgeInterpolator` — keep the exact FP
+expression shapes (`(width * (y - p1.y)) / height`, midpoint for `|height| < EPSILON`), only
+collapsing storage. No arithmetic changes → bit-exact.
+(b) SAFE: extract the SDF bilinear fetch + coverage evaluation into one private static helper
+called from both SDF writers — it is already byte-identical, so extraction cannot change
+output if the expression text moves verbatim (watch implicit constant folding: keep `int`
+casts and shifts identical).
+(c) SAFE: single-source the edge-pair Y-scan loop as a small static helper taking the three
+interpolators + a span callback — control-flow only.
+(d) UNSAFE without re-golden: merging the two blend formulas. Don't — instead add a comment at
+each site naming the formula and why they differ, or standardize deliberately and re-bless
+goldens as a separate, announced change.
+
+Risk: (a)-(c) LOW if done as verbatim text motion (FP op order preserved); (d) is a visible
+output change — treat as a feature, not a refactor. HouseGoldens/Fo4Shot are the gate.
+
+## [MEDIUM] 7. RenderingContext: ~45 fields in the wrong package
+
+`gui/RenderingContext.java` (707 lines). 43 instance fields + 2 statics; 22 public non-final
+(measured). Natural clusters:
+
+- Framebuffer: bufferedImage (158), pixels (91), depth (99), graphics (78), segmentGraphics
+ (85), width/height (126/131).
+- Projection: centerCoordinate (137), projectionScale (144), nearPlaneDistance (184),
+ frustum (289), viewerPosition (298).
+- Tile/viewport geometry: tilesX/tilesY/viewportCount/numRenderSegments (63-72),
+ renderMinY/MaxY (150/156, **final**), renderMinX/MaxX (274/281, **mutable** — asymmetric,
+ mutated post-construction at ViewPanel:1224-1225), stereo* (255-267).
+- Pipeline bookkeeping: vertexSlot (176), frameNumber (190), transformCycleId (166),
+ presentGate (344), depthPass (109), transformExecutor (324), transformCoordinator (333),
+ lastTransformTaskCount (350).
+- Culling: subpixelCullingThreshold/Epoch (198/208), cullingStatistics (306),
+ occlusionPyramid (316).
+- Mouse picking (~120 lines incl. methods 627-705): mouseEvent (222),
+ objectPreviouslyUnderMouseCursor (213), currentObjectUnderMouseCursor (226),
+ currentMouseTextureU/V (231-232).
+- Services smuggled through: developerTools (237), debugLogBuffer (243), lightingManager (250).
+
+Belongs elsewhere: mouse-picking state+methods → `MousePickState` (owned by context, one
+field); `presentGate` → pipeline glue owned by the scheduler/ViewPanel (it is only written at
+ViewPanel:617-619 and awaited in the paint continuation); `depthPass` → RenderAggregator
+passes it to shapes via context purely as a side-channel; `lastTransformTaskCount` →
+diagnostics bundle; `lightingManager`/`developerTools`/`debugLogBuffer` → a small
+`FrameServices` bag would cut constructor/copy-constructor duplication.
+
+Also note the two copy constructors (442-470, 482-521) enumerate fields by hand and already
+diverge (the pass copy omits frustum "by design" — comment 520 — and silently drops
+presentGate/lastTransformTaskCount). Every new field must be added in up to 3 places; this is
+where the next pipeline bug comes from.
+
+Refactor sketch: (1) move class to renderer.raster (see finding 2); (2) extract MousePickState
+(whole methods move); (3) move presentGate to the scheduler; (4) cluster remaining fields into
+final sub-objects (Framebuffer, ViewportGeometry) so the copy constructors shrink to field
+copies of immutable parts + shallow shares.
+
+Risk: LOW-MEDIUM — all mechanical, but the class is read by ~every shape; keep accessors as
+delegates so shape code (`renderBuffer.pixels`, `.depth`, `.renderMinX`…) is untouched until a
+second pass updates call sites. No FP code → goldens safe. The public-field style means
+consumers may read these fields directly; keep the same field names visible during transition.
+
+## [MEDIUM] 8. OctreeVolume: 560-line copy-paste tracer + fully public internals
+
+`renderer/octree/OctreeVolume.java` (1102 lines), used only by demos' OctreeDemo.
+
+- Raw storage exposed: `public int[] cell1..cell8` (42-56), `public int cellAllocationPointer`
+ (61), `usedCellsCount` (64), `masterCellSize` (67), plus `initWorld` (298) re-allocating the
+ arrays under any concurrent reader. Invariants (cell state encoding -1/-2, 0 = null child)
+ are unenforceable.
+- `doesIntersect` (133-248): 7 near-identical ~16-line face slabs.
+- `traceCell` (512-1100): 8 octant branches × up to 7 recursive-probe stanzas each (~12 lines
+ per stanza) — ~560 lines of mechanical copy-paste with hand-maintained visit orders
+ ("// 6 8 3 5 2 4 1", 533).
+- `getNewCellPointer` (335-350): linear-scan allocator with wraparound; infinite-loops when the
+ buffer is full (no exhaustion check) — a latent hang, not just style.
+
+Refactor sketch: (a) represent the 8 children as `int[][] children` or one `int[8]` per cell
+indexed by octant — the putCell sub-cube selection (411-461) and traceCell collapse to loops
+over octant index with a precomputed per-ray-octant visit-order table (8 orders × 8 octants,
+64 entries, generated once). That alone removes ~500 lines. (b) Encapsulate arrays; add
+exhaustion failure in getNewCellPointer (return -1 / throw) instead of an infinite loop.
+(c) Optionally extract the ray-trace half (doesIntersect/traceCell) into `OctreeRayWalker`.
+
+Risk: LOW correctness-wise for (b) and the hang fix; MEDIUM for (a) — visit order affects
+*which* cell is returned first for ties, and OctreeDemo visuals depend on it. Not covered by
+golden tests (octree is not in the golden harnesses), so verify by side-by-side OctreeDemo
+screenshots. This subsystem is demo-only; alternatively quarantine it as-is and spend effort
+elsewhere.
+
+## [LOW] 9. AbstractCoordinateShape: slot-explosion + internal duplication
+
+- 12 scalar fields + 3 lists encode "screen state × 3 slots" (83-110, 165-175); accessors
+ repeat the same 3-way ternary 7 times (218-271).
+- `setSlotScreenState` (126-148) and the write block inside `transform` (503-521) are the same
+ 3-way branch twice — `transform` could call `setSlotScreenState(slot, …)` (one-line fix).
+- Stale docs: six accessors say "slot (0 or 1)" (226, 236, 246, 256, 266, 276) though slots are
+ 0/1/2.
+
+Refactor sketch: introduce `private final ScreenState[] slots = {new ScreenState(), …}` (z,
+minY, maxY, minX, maxX, clippedVertices) — collapses 15 fields to 1 array + deletes 7 branchy
+accessors. Keep public method signatures. Risk: ZERO pixel risk (pure storage, no FP
+expressions), LOW merge risk; internal-only.
+
+## [LOW] 10. API surface & documentation drift
+
+- `ViewPanel.setFrameRate` (957) vs `getTargetFPS` (966) — setter/getter name mismatch
+ (setTargetFPS expected).
+- TexturedTriangle javadoc links to methods that no longer exist: `{@link
+ #drawHorizontalLinePerspective}` (214), `{@link #drawHorizontalLine}` (318, 1090, 1308,
+ 1354, 1381) — the class has only the …Z/…Sdf variants (verified: no `drawHorizontalLine(`
+ definition). Javadoc build emits warnings for these.
+- Stale pipeline comments on the most subtle code: "Double-buffered frame contexts" (ViewPanel
+ 160) over a 3-element array (165); "Parity (0/1)" (167) while `frameParity = (frameParity +
+ 1) % 3` (645); duplicated/orphaned javadoc stub above `getInputManager` (394-402).
+- ShapeCollection slot docs say "(0 or 1)" (428, 469); a commented-out code block + TODO
+ (336-337); slot-0-only helpers (`sortShapes()` 421, `getQueuedShapeCount` 499,
+ `getBinSizes` 520) beside slot-parameterized siblings — test-only callers, fine, but mark
+ them as such.
+- Direct field poke across classes: `AbstractCompositeShape.setColor` writes
+ `((Line) shape).color = color` (404) into Line's public field (Line.java:61) instead of a
+ setter — bypasses any future invalidation logic.
+- `RenderingContext.bufferedImageType` (48) — constant not in CONSTANT_CASE.
+- `RenderAggregator.ShapesZIndexComparator implements Serializable` (844) — nothing
+ serializes it; also `import java.io.Serializable` (10).
+
+Risk: ZERO-LOW. All are comment/name/mechanical fixes; renaming setFrameRate would break
+consumers — prefer adding a correctly-named alias and deprecating.
+
+---
+
+## Verdict
+
+**Yes — the architecture is sound for a software rasterizer of this size.** The load-bearing
+structure (transform/sort/bin/paint phases, triple-buffered pipeline with per-slot vertex
+state, painter + z-buffer two-pass visibility, Hi-Z, SoA TriangleMeshBlock) is deliberately
+designed, and unusually well documented: the comments record *measurements and dates* (e.g.
+ViewPanel:113-116, 219-221, 1299-1309; AbstractCompositeShape:1009-1012), which is exactly the
+evidence-based culture that keeps a performance codebase honest. The problems are not the
+design but **entropy concentrated in identifiable places**: ViewPanel's ten responsibilities,
+RenderingContext's 45-field blob sitting in the wrong package (which drags the whole import
+graph into cycles), and hand-maintained copy-paste in the span writers and the octree tracer.
+None of these threaten correctness today; all of them raise the cost of the *next* change.
+The recommended program is: (1) delete the verified dead code (free), (2) package relocation +
+RenderingContext/ViewPanel extraction (mechanical, no FP risk), (3) safe de-duplication only —
+interpolators, identical SDF block, scan-loop helper — leaving the two blend formulas alone,
+(4) extract CSG and the transform planner from AbstractCompositeShape. Every step except
+octree rework is gateable by the existing golden harnesses with bit-exact expectations.
--- /dev/null
+# aukio-3d performance review — what's left on the table
+
+Read-only static analysis, 2026-09-20. Scope: span writers, AoS-vs-SoA split, sort/bin/transform,
+memory layout, threading, SDF text path, GI/octree. All line numbers against current HEAD.
+
+Known-good state (verified, not re-litigated): parallel chunk transform with pooled scratch,
+radix sort over packed long keys, CSR tile bins, tiled MT paint with two-pass z-buffer,
+Hi-Z block culling, subpixel epoch cache, TriangleMeshBlock SoA transform loop.
+
+---
+
+## Tier 1 — multi-ms/frame class at 500k queued triangles
+
+### 1. Radix sort runs single-threaded; the executor handed to `sort()` is ignored in the radix path
+`RenderAggregator.sort(ExecutorService)` (`RenderAggregator.java:162-165`):
+```java
+if (executor != null && sortedCount >= PARALLEL_SORT_THRESHOLD) {
+ if (!tryRadixSort(sortedArray, sortedCount)) // <- executor NOT passed
+ parallelMergeSort(sortedArray, sortedCount, comparator, executor);
+```
+`tryRadixSort` (`RenderAggregator.java:187-228`) is one serial loop: key build
+(`:193-196`, one virtual `getZ(slot)` per shape), then `RadixLongSort.sortPairs`
+(`RadixLongSort.java:66-98`) = 8 LSD passes, each streaming 500k×(8B key + 4B idx) read +
+12B scatter-write ≈ 96 MB of traffic on ONE core, then a serial random-gather permute
+(`:224-226`) plus a full `System.arraycopy` back. This is the measured ~17 ms sort.
+Bonus: `tryRadixSort` ends `return true` unconditionally — `parallelMergeSort` is dead code.
+
+- Why slow: serial memory-bound passes on one core while 17 workers idle (sort sits between
+ drain and bin in the paint continuation — `ViewPanel.java:1200-1205` — so it directly
+ delays paint-task submission every pass).
+- Change sketch: parallel LSD radix on the same pool — per-chunk 256-bin histograms (parallel),
+ serial 256×chunks prefix, parallel stable scatter with per-(chunk,digit) offsets. Fixed chunk
+ boundaries + stability = bit-identical output to today (keys exact, equal-key order preserved,
+ tie-run shapeId fix unchanged). Also: permute into the *other* grow-only buffer and swap
+ references instead of `arraycopy` back (saves one 4 MB serial copy). Even simpler first step:
+ parallelize only the key build by folding it into `mergeAllParallel`'s already-parallel copy
+ (`RenderAggregator.java:755-790`) — compute `zSortKey` while copying each part.
+- Impact class: sort 17 ms → ~4-6 ms wall. The largest single remaining pipeline lever.
+
+### 2. Per-triangle raster setup is recomputed per overlapped tile, per frame
+`TexturedTriangle.paintFlat` (`TexturedTriangle.java:621-628`):
+```java
+final double edge12 = projectedPoint1.getDistanceTo(projectedPoint2); // sqrt
+final double edge13 = projectedPoint1.getDistanceTo(projectedPoint3); // sqrt
+final double edge23 = projectedPoint2.getDistanceTo(projectedPoint3); // sqrt
+final double scaleFactor = (totalVisibleDistance / totalTextureDistance) * 1.2d;
+final TextureBitmap mipmap = texture.getMipmapForScale(scaleFactor);
+```
+plus the perspective setup (`:673-682`, three `1d/z` divides + muls) and the per-span curvature
+ladder (`:322-335`, ~7 divides per span). All of this depends only on transform-phase outputs,
+yet `paint()` runs once per overlapped tile — a triangle in 4 tiles pays it 4×.
+Worse on the object path: `paintTriangle` (`:492-497`) computes the same three `getDistanceTo`
+values, then `paintFlat` recomputes them — 6 sqrt per tile-paint for non-SDF triangles.
+And `MeshTriangle.paint` (`MeshTriangle.java:109`) calls `block.origTtd(index)`
+(`TriangleMeshBlock.java:444-456`) = 3 sqrt over the *final, build-time* `uv[]` array,
+recomputed every paint of every tile of every frame.
+
+- Why slow: sqrt ~15-20c each; at ~150k painted triangles × ~1.5 tiles × (3-6 sqrt + divides)
+ ≈ 30-60M cycles/frame aggregate paint-side setup that is definitionally redundant.
+- Change sketch (bit-exact — same expressions, evaluated once instead of N times):
+ compute `scaleFactor`/mip level/affine-vs-perspective flag once per triangle per slot in
+ `TriangleMeshBlock.transform` (mesh path) / `AbstractCoordinateShape.transform` (object path),
+ stash in per-slot handle state, pass into `paintFlat`. Precompute `origTtd` into a
+ `double[]` at block build (uv is final). In `paintTriangle`, pass the already-computed
+ `scaleFactor` down instead of recomputing.
+- Impact class: ~1-3 ms/frame aggregate at FO4 queue sizes; larger for big-screen triangles
+ (text quads, terrain near the camera) that span tens of tiles.
+
+### 3. Scanline edge evaluation: per-getter divisions + per-scanline edge re-selection
+`PerspectiveBorderInterpolator.getSU/getSV/getSW/getZW` (`PerspectiveBorderInterpolator.java:112-148`)
+each call `interpolationT()` = `(currentY - p1.y) / height` — a **double division per getter**.
+`drawHorizontalLinePerspectiveZ` (`TexturedTriangle.java:233-259`) calls getX + 4 channel getters
+per edge per scanline: up to 10 divisions/scanline if C2 doesn't CSE them across the inlined
+getters, 4 if it does (getX's `(width * (currentY - p1.y)) / height` is a different expression
+than `width*t`, so it never shares). Same shape in `PolygonBorderInterpolator`
+(`:98-119,129-134,189-194`) and `LineInterpolator.getX/getZW` (`:100-105,144-149`).
+Additionally `containsY` (`PerspectiveBorderInterpolator.java:101-105`) recomputes
+`Math.min/max(p1.y,p2.y)` per call, and the triangle y-loop (`TexturedTriangle.java:698-708`)
+re-tests 2-3 `containsY` per scanline to re-derive which edge pair is active — when the pair
+only changes once, at the middle vertex.
+
+- Why slow: double div ~13-20c; even at the CSE-friendly 4/scanline that's 50-80c/scanline of
+ division alone. At 500k queued tris with mean height ~5-15 scanlines, several M scanlines/frame
+ → multiple ms of pure edge math, concentrated on exactly the small distant triangles that
+ dominate the FO4 scene.
+- Change sketch:
+ a) bit-exact: cache `minY/maxY` at `setPoints`; make one explicit `t = (currentY-p1.y)/height`
+ per edge per scanline and pass it to the four channel reads (identical expression →
+ identical bits, and no longer JIT-CSE-dependent).
+ b) needs-tolerance: express `x = p1.x + width*t` (removes the second div; differs by ≤1ulp
+ from `(width*dy)/height` — golden tolerance should absorb, verify).
+ c) bit-exact with care: split the y-loop into [yTop..yMid] and (yMid..yBottom] halves with the
+ edge pair fixed per half (the current inclusive `containsY` semantics pin which pair owns
+ the seam scanline — replicate). Removes ~3 containsY + min/max per scanline.
+- Impact class: ~2-5 ms/frame aggregate at small-triangle-heavy views.
+
+---
+
+## Tier 2 — ~0.5-2% frame time each, cheap and safe
+
+### 4. Depth margin costs 2 muls + 1 sub per pixel even though it defaults to 0
+All four z-buffered span writers test
+```java
+if (zw > depth[offset] - RenderingContext.DEPTH_MARGIN_DZ * zw * zw)
+```
+`TexturedTriangle.java:356` (perspective-Z), `:1386` (affine-Z), `SolidPolygon.java:354,370`.
+`DEPTH_MARGIN_DZ` (`RenderingContext.java:120-121`) parses `-Daukio.zbuffer.margin`, default `"0"`.
+It's `static final` so C2 folds the constant to 0.0, but `0.0 * zw * zw` is NOT eliminable
+(NaN semantics), so every z-tested pixel pays two dependent muls + a sub for a disabled feature.
+
+- Change sketch (bit-exact: `0.0*zw*zw == +0.0` and `d - 0.0 == d` exactly for finite zw, which
+ near-plane clipping guarantees): hoist once per span —
+ `final boolean strict = DEPTH_MARGIN_DZ == 0;` and branch to a margin-free loop copy, or
+ duplicate the pixel loops under one perfectly-predicted branch. If margin>0 is ever used,
+ the quadratic term can also be strength-reduced (`m += (2*c*dzw)*zw + c*dzw*dzw`, both
+ coefficients span-invariant) — that variant reassociates FP, so tolerance-check it.
+- Impact class: ~1-1.5c/pixel on every z-tested pixel; at 2-4M tested pixels/frame ≈ 0.5-1%
+ frame time, for near-zero code risk.
+
+### 5. Hi-Z pyramid build is a serial full-depth-buffer sweep on the render thread; `occluded()` is `synchronized`
+`ViewPanel.flushPendingPaint` (`:825-829`) calls `HiZPyramid.buildFrom` on the render thread
+after each pass. `buildFrom` (`HiZPyramid.java:61-108`) min-pools the entire float depth buffer
+(8×8 tiles) single-threaded: 8.3 MB @1080p, ~14.7 MB @1440p, ~58 MB at the 4920×2960 stereo
+buffer — ~1-2 ms, up to ~5 ms, serial, before the next transform fork can start.
+And `occluded()` (`:121`) is `synchronized` — every `TriangleMeshBlock.transform` on every
+parallel chunk thread (`TriangleMeshBlock.java:184-216`) takes the same monitor, serializing
+block tests against each other and against the multi-ms build.
+
+- Change sketch: build level 0 per tile in the paint workers' epilogue (depth just written is
+ still in L2), reduce upper levels serially (tiny); publish the pyramid as an immutable
+ per-build snapshot behind a volatile reference and drop `synchronized` from `occluded()`
+ (reads are all from the snapshot). Telemetry `AtomicLong`s → LongAdder.
+- Impact class: ~1-2% @1440p mono, ~5% at 4K-class buffers; removes a contention edge that
+ scales with block count × worker count.
+
+### 6. SDF text path: 257×Math.pow + LUT allocation + 2×hypot + 2×log per triangle **per tile** per frame
+`TexturedTriangle.paintSdf` (`:789-961`) runs per tile-paint (a text canvas quad overlapping
+N tiles paints N times). Per call:
+- `Math.hypot` ×2 for footprints (`:820-821`) — hypot pays overflow-safe scaling;
+ `sqrt(x*x+y*y)` is 3-5× cheaper (≤1ulp difference: tolerance-check),
+- auto-gamma does `Math.log` ×2 (`:863-864`),
+- when minified (any text past arm's length): `covLut = new int[257]` + 257×`Math.pow`
+ (`:865-869`). For a terminal-sized canvas (~2 triangles × 50-100 tiles) that's
+ ~200 × (257 pow + 1 KB alloc) ≈ 2M cycles per frame per canvas.
+
+- Change sketch: cache the LUT — gamma is a smooth function of `maxFootprint`; quantize gamma
+ to 1/256 steps and keep a per-thread last-LUT (or a tiny `ConcurrentHashMap<Integer,int[]>`).
+ Hoist footprint/gamma/aaK to once per triangle per frame (paint-margin-free, so it's
+ tile-invariant). This is computation caching, not allocation pooling.
+- Inner loop: the fixed-point bilinear (`:1037-1038` and `:1211-1212`) uses 8 int muls; the
+ two-lerp form `top = m00*(256-fx)+m10*fx; bot = m01*(256-fx)+m11*fx; d=(top*(256-fy)+bot*fy)>>16`
+ is **bit-identical** (integer associativity; worst case 33.4M < 2^31, no overflow) at 4 muls.
+ Halves the mask-eval multiply count on every text pixel.
+- Impact class: workspace/terminal views (aukio TerminalPanel renders through this path):
+ ~1-3 ms/frame with several text canvases; FO4: negligible.
+
+---
+
+## Tier 3 — smaller or situational
+
+### 7. Two-pass paint visits every bin entry twice
+`RenderAggregator.paintSorted` (`:353-366`) iterates each tile's bin twice;
+`paintRange` (`:370-397`) virtual-calls `paint()` on every entry in both passes and the shape
+early-outs (`TexturedTriangle.paintFlat:563-565`, `SolidPolygon.paint:703-705`) only after a
+volatile texture load + field reads. One of the two visits is always waste: ~queue×tiles
+no-op dispatches per frame (~750k at 500k×1.5 tiles ≈ 0.5-1% frame).
+- Sketch: split each bin into [opaque|alpha] segments at CSR build time (two counts per tile —
+ binning order within each class preserved, so pixels are bit-identical); pass 1 walks the
+ opaque segment reversed, pass 2 the alpha segment forward.
+
+### 8. Mip-chain lazy build races across paint threads; level selection loops per paint
+`Texture.getDownscaledBitmap` (`Texture.java:278-291`) checks `downSampled[i] == null` and
+builds unsynchronized while 18 paint threads may first-touch the same level on the same frame
+→ duplicated full box-filter chain builds per texture (startup stutter on texture-heavy loads),
+and the array-slot write has no happens-before edge. `getDownscaleMipmapLevel` (`:180-189`)
+loops ≤8 iterations per triangle per tile-paint.
+- Sketch: synchronize per-texture on build (or prebuild chains at texture-load time in the
+ FO4 `TextureSource`); publish via the array only after construction (final fields make the
+ bitmap itself safe). Replace the halving loop with an exponent-based level pick
+ (`Math.getExponent`) — verify threshold equivalence for exact powers of two.
+
+### 9. Octree ray tracer (OctreeDemo path): allocation-per-face-test and non-parametric traversal
+`OctreeVolume.doesIntersect` (`OctreeVolume.java:133-248`) allocates a `new Point3D` (or
+`clone()`) on *every* face candidate — up to 6 allocations per cell visit — and
+`traceCell` (`:512-1100`) orders children by the **origin's octant**, not by parametric
+distance along the ray. Because the first solid hit returns immediately, this is both slower
+(no near-first pruning; every level re-runs 6-division slab tests per child from scratch) and
+suspect (can return a farther voxel over a nearer one when the origin is outside the parent
+cell). `RayTracer.run` (`RayTracer.java:157-175`) allocates a `Ray` + 2 `Point3D` + `Color`
+per pixel and does 3 divides/pixel for view-plane interpolation (`(x3p * x) / width` — should
+be incremental adds); `traceRay` then fires 6 shadow rays × 2 Point3D + Ray allocations per
+light. `getNewCellPointer` (`:335-350`) is a linear scan for a free cell — O(cells) per
+allocation, so filling big voxel volumes is O(n²).
+- Sketch (only if OctreeDemo matters; nothing in FO4 touches this): slab test with precomputed
+ per-ray inverse direction, hit point computed once from the winning t (no per-face allocs),
+ Revelles-style parametric child ordering, free-list for cells.
+- Impact: background/progressive demo renderer — not frame-critical.
+
+### 10. GI package: BVH build and query constant factors
+`TriangleBvh.build` (`TriangleBvh.java:92-96`) sorts at every tree level with a comparator →
+O(n log² n) build per snapshot rebuild (median selection via quickselect is O(n log n) and
+lambda-free). `rayBox` (`:172-198`) does 6 divisionss per node visit + NaN fixup branches —
+precompute `1/dx,1/dy,1/dz` once per ray and multiply (not bit-identical to division; GI
+output feeds lightmaps, not golden pixels — still verify). `nearestNode` (`:123-140`) visits
+left before right unconditionally; ordering children by nearer-box-first makes the `hit.t`
+bound prune the far child far more often (typically ~2× fewer node visits on nearest-hit).
+`GlobalIllumination.updateComposites` (`:610-637`) fills invalid lightmap texels with a
+`while(progressed)` whole-map rescan — O(texels × map diameter); a BFS/multi-source queue is
+O(texels). Per-sample `new double[3]` returns (`:537`, `:890`) churn on the GI threads —
+background threads, so low stakes, but free to remove.
+- Impact: GI convergence latency and background CPU burn only; render path is unaffected
+ (render-side GI cost is already ~zero by design).
+
+---
+
+## Question 2 answer: how much AoS is left, and is extending SoA worth it?
+
+FO4 (the 500k-tri target): **~100% mesh blocks.** `NifSceneBuilder.java:169-222` (nif parts) and
+`WorldStreamer.java:1309-1348` (terrain cells) both emit `TriangleMeshBlock` by default
+(`aukio.fo4.meshBlocks`, default true); the `new TexturedTriangle` fallbacks
+(`NifSceneBuilder.java:244`, `WorldStreamer.java:1420`) are behind the same flag.
+`SolidPolygon` is imported in WorldStreamer but never instantiated for geometry.
+
+AoS `Vertex`-graph shapes (SolidPolygon, Line, Billboard, SDF text quads, lightmapped
+triangles) carry 8-9 heap objects per vertex with per-slot pointer chasing — they remain in:
+- demos/benchmarks: SolidCubesTest 16³ cubes ≈ 49k triangles, LitSolidCubesTest, sphere scenes;
+- the Aukio workspace UI (TerminalPanel → TextCanvas → 2 SDF triangles per panel);
+- CSG/lightmapped content where per-shape objects are semantically needed.
+
+Verdict: extending SoA to a `SolidPolygonMeshBlock` would only move the cube/sphere demos —
+not the FO4 number. **Not worth it** for the stated target; the remaining AoS cost is in
+small-N UI/demo scenes where per-shape setup, not pointer chasing, dominates anyway.
+
+## Question 4 answer: memory layout
+
+Pixel buffer and depth buffer are both row-major with identical addressing
+(`y*width + x` everywhere) — span writes are unit-stride in both, tile clears use
+`Arrays.fill` per row (intrinsic-vectorized). No column-major striding anywhere in the hot
+paths. Texture reads (`ity*texW+itx`) stride by texture row — inherent to UV mapping and
+already mitigated by the mip chain. The only structural note: pixels and depth are two
+separate arrays, so each z-tested pixel write touches two cache lines; interleaving them
+would break `BufferedImage` blit interop — not recommended.
+
+## Question 5 answer: thread utilization
+
+Tiles = 10×workers, near-square (`ViewPanel.java:1548-1552`, TILES_PER_THREAD=10) with one
+task per tile on a work-stealing ForkJoinPool (75% of cores, measured choice) — sound.
+Per-pass `CountDownLatch(segments)` is one await per frame, negligible. Two notes: the paint
+continuation (`ViewPanel.java:1177-1268`) blocks a worker on `previousGate.await`
+(`CountDownLatch` — no FJP compensation) — at most a few parked workers, fine; and the
+serial sort inside that continuation is the real utilization gap (finding 1).
+
+---
+
+## Verdict
+
+The architecture is **not** at the pure-Java ceiling. The big structural pieces are right
+(SoA transform, radix keys, CSR bins, tiled two-pass z, Hi-Z), but there is one large and
+several medium wins left, all compatible with bit-exactness or within stated tolerance:
+
+**Top 3:**
+1. **Parallelize the radix sort** (it's single-threaded inside a pool it was explicitly
+ handed): ~17 ms → ~4-6 ms at 500k shapes. `RenderAggregator.java:162-228`.
+2. **Hoist per-triangle raster setup out of per-tile paint** (mip metric sqrt×3, `origTtd`,
+ perspective divides — computed once per slot, not once per tile-overlap):
+ `TexturedTriangle.java:492-497,621-682`, `MeshTriangle.java:109`. Plus the guaranteed-safe
+ half of the scanline-divide fix (cached min/max, one explicit shared `t` per edge).
+3. **Kill the default-disabled depth-margin math in the four z-span writers**
+ (strict-loop specialization, bit-exact) — ~0.5-1% of frame for a few lines;
+ and **de-serialize the Hi-Z build + lock-free `occluded()`** — ~1-2% at 1440p, more at 4K.
+
+(3 is two cheap items bundled; if forced to pick three single items: parallel radix, setup
+hoisting, scanline edge-evaluation restructure.)
--- /dev/null
+.flex-center {
+ display: flex;
+ justify-content: center;
+}
+
+.flex-center video {
+ width: min(90%, 1000px);
+ height: auto;
+}
+
+.responsive-img {
+ width: min(100%, 1000px);
+ height: auto;
+}
+
+/* === SVG diagram theme === */
+svg > rect:first-child {
+ fill: #061018;
+}
+
+svg text[fill="#666"],
+svg text[fill="#999"] {
+ fill: #aaa !important;
+}
+
+svg line[stroke="#ccc"] {
+ stroke: #445566 !important;
+}
+
+svg {
+ background-color: #061018;
+ border-radius: 8px;
+ display: block;
+ margin: 0 auto;
+}
\ No newline at end of file
--- /dev/null
+* Demos
+:PROPERTIES:
+:CUSTOM_ID: demos
+:END:
+** Add more math formula examples to "Mathematical formulas" demo
+:PROPERTIES:
+:CUSTOM_ID: add-more-math-formula-examples
+:END:
+
+* Performance
+:PROPERTIES:
+:CUSTOM_ID: performance
+:END:
+** Group identical Vertices into one during object slicing
+Now system will need to compute each unique point in 3D only
+once. Polygons can share coordinates.
+
+** Add dynamic resolution support
+:PROPERTIES:
+:CUSTOM_ID: add-dynamic-resolution-support
+:END:
++ When there are fast-paced scenes, dynamically and temporarily reduce
+ image resolution if needed to maintain desired FPS.
+
+** Add object fading based on view distance
+:PROPERTIES:
+:CUSTOM_ID: add-object-fading-view-distance
+:END:
+Goal: make it easier to distinguish nearby objects from distant ones.
+
+** Add polygon reduction based on view distance (LOD)
+:PROPERTIES:
+:CUSTOM_ID: add-polygon-reduction-lod
+:END:
+
+** Compute global illumination at progressive resolutions
+
+At startup, initially compute global illumination using very coarse
+lightmap. Then progressively keep recomputing it with finer and finer
+level of detail. Once lightmap stabilizes, stop lightmap computation
+until there is change in the scene.
+
+* Features
+:PROPERTIES:
+:CUSTOM_ID: features
+:END:
+** Make it possible to configure field of view (FOV)
+** Add collision detection (physics engine)
+* Add clickable vertexes
+:PROPERTIES:
+:CUSTOM_ID: add-clickable-vertexes
+:END:
+
+Circular areas with radius. Can be visible, partially transparent or
+invisible.
+
+Use them in 3D graph demo. Clicking on vertexes should place marker
+and information billboard showing values at given XYZ location.
+
+Add formula textbox display on top of 3D graph.
+- Consider making separate formula explorer app where formula will be
+ editable and there will be gallery of pre-vetted formulas.
+ - make this app under Aukio parent project.
+ - Consider integrating with FriCAS or similar CAS software so that
+ formula parsing and computation happens there.
+
++ Study and apply where applicable
+
++ Read this as example, and apply improvements/fixes where applicable:
+ http://blog.rogach.org/2015/08/how-to-create-your-own-simple-3d-render.html
+
++ Improve triangulation. Read: https://ianthehenry.com/posts/delaunay/
+
+* Aukio 3D Demos
+
+** Text editors demo
+
++ Improve focus handling:
+ + Perhaps add shortcut to navigate world without exiting entire
+ stack of focus.
+ + Possibility to retain and reuse recently focused elements.
+ + Store user location in the world and view direction with the
+ focused window. So that when returning focus to far away object,
+ user is redirected also to proper location in the world.
+
++ Possibility to store recently visited locations in the world and
+ return to them.
+
--- /dev/null
+#!/bin/bash
+
+# This script launches IntelliJ IDEA with the current project
+# directory. The script is designed to be run by double-clicking it in
+# the GNOME Nautilus file manager.
+
+# First, we change the current working directory to the directory of
+# the script.
+
+# "${0%/*}" gives us the path of the script itself, without the
+# script's filename.
+
+# This command basically tells the system "change the current
+# directory to the directory containing this script".
+
+cd "${0%/*}"
+
+# Then, we move up one directory level.
+# The ".." tells the system to go to the parent directory of the current directory.
+# This is done because we assume that the project directory is one level up from the script.
+cd ..
+
+# Now, we use the 'setsid' command to start a new session and run
+# IntelliJ IDEA in the background. 'setsid' is a UNIX command that
+# runs a program in a new session.
+
+# The command 'idea .' opens IntelliJ IDEA with the current directory
+# as the project directory. The '&' at the end is a UNIX command that
+# runs the process in the background. The '> /dev/null' part tells
+# the system to redirect all output (both stdout and stderr, denoted
+# by '&') that would normally go to the terminal to go to /dev/null
+# instead, which is a special file that discards all data written to
+# it.
+
+setsid idea . &>/dev/null &
+
+# The 'disown' command is a shell built-in that removes a shell job
+# from the shell's active list. Therefore, the shell will not send a
+# SIGHUP to this particular job when the shell session is terminated.
+
+# '-h' option specifies that if the shell receives a SIGHUP, it also
+# doesn't send a SIGHUP to the job.
+
+# '$!' is a shell special parameter that expands to the process ID of
+# the most recent background job.
+disown -h $!
+
+
+sleep 2
+
+# Finally, we use the 'exit' command to terminate the shell script.
+# This command tells the system to close the terminal window after
+# IntelliJ IDEA has been opened.
+exit
--- /dev/null
+#!/bin/bash
+cd "${0%/*}"; if [ "$1" != "T" ]; then gnome-terminal -e "'$0' T"; exit; fi;
+
+cd ..
+
+# Function to export org to html using emacs in batch mode
+export_org_to_html() {
+ local org_file=$1
+ local dir=$(dirname "$org_file")
+ local base=$(basename "$org_file" .org)
+ (
+ cd "$dir" || return 1
+ local html_file="${base}.html"
+ if [ -f "$html_file" ]; then
+ rm -f "$html_file"
+ fi
+ echo "Exporting: $org_file → $dir/$html_file"
+ emacs --batch -l ~/.emacs --visit="${base}.org" --funcall=org-html-export-to-html --kill
+ if [ $? -eq 0 ]; then
+ echo "✓ Successfully exported $org_file"
+ else
+ echo "✗ Failed to export $org_file"
+ return 1
+ fi
+ )
+}
+
+export_org_files_to_html() {
+ echo "🔍 Searching for .org files in Documentation/ ..."
+ echo "======================================="
+
+ mapfile -t ORG_FILES < <(find Documentation -type f -name "*.org" | sort)
+
+ if [ ${#ORG_FILES[@]} -eq 0 ]; then
+ echo "❌ No .org files found!"
+ return 1
+ fi
+
+ echo "Found ${#ORG_FILES[@]} .org file(s):"
+ printf '%s\n' "${ORG_FILES[@]}"
+ echo "======================================="
+
+ SUCCESS_COUNT=0
+ FAILED_COUNT=0
+
+ for org_file in "${ORG_FILES[@]}"; do
+ export_org_to_html "$org_file"
+ if [ $? -eq 0 ]; then
+ ((SUCCESS_COUNT++))
+ else
+ ((FAILED_COUNT++))
+ fi
+ done
+
+ echo "======================================="
+ echo "📊 SUMMARY:"
+ echo " ✓ Successful: $SUCCESS_COUNT"
+ echo " ✗ Failed: $FAILED_COUNT"
+ echo " Total: $((SUCCESS_COUNT + FAILED_COUNT))"
+ echo ""
+}
+
+build_visualization_graphs() {
+ rm -rf Documentation/graphs/
+ mkdir -p Documentation/graphs/
+
+ javainspect -j target/aukio-3d-*-SNAPSHOT.jar -d Documentation/graphs/ -n "All classes" -t png -ho
+ javainspect -j target/aukio-3d-*-SNAPSHOT.jar -d Documentation/graphs/ -n "GUI" -t png -w "eu.svjatoslav.aukio.e3d.gui.*" -ho
+ javainspect -j target/aukio-3d-*-SNAPSHOT.jar -d Documentation/graphs/ -n "Raster engine" -t png -w "eu.svjatoslav.aukio.e3d.renderer.raster.*" -ho
+
+ meviz index -w Documentation/graphs/ -t "Aukio 3D classes"
+}
+
+# Build project jar file and JavaDocs
+mvn clean package
+
+# Put generated JavaDoc HTML files to documentation directory
+rm -rf Documentation/apidocs/
+cp -r target/apidocs/ Documentation/
+
+# Publish Emacs org-mode files into HTML format
+export_org_files_to_html
+
+# Generate nice looking code visualization diagrams
+build_visualization_graphs
+
+
+## Upload assembled documentation to server
+echo "📤 Uploading to server..."
+rsync -avz --delete -e 'ssh -p 10006' Documentation/ \
+ n0@www3.svjatoslav.eu:/mnt/big/projects/aukio-3d/
+
+if [ $? -eq 0 ]; then
+ echo "✓ Upload completed successfully!"
+else
+ echo "✗ Upload failed!"
+fi
+
+echo ""
+echo "Press ENTER to close this window."
+read
--- /dev/null
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+ <modelVersion>4.0.0</modelVersion>
+ <groupId>eu.svjatoslav</groupId>
+ <artifactId>aukio-3d</artifactId>
+ <version>1.1.0-SNAPSHOT</version>
+ <name>Aukio 3D</name>
+ <description>3D engine</description>
+
+ <properties>
+ <java.version>21</java.version>
+ <maven.compiler.source>21</maven.compiler.source>
+ <maven.compiler.target>21</maven.compiler.target>
+ <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+ <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
+ </properties>
+
+ <organization>
+ <name>svjatoslav.eu</name>
+ <url>https://svjatoslav.eu</url>
+ </organization>
+
+ <dependencies>
+ <dependency>
+ <groupId>net.java.dev.jna</groupId>
+ <artifactId>jna</artifactId>
+ <version>5.14.0</version>
+ </dependency>
+
+ <dependency>
+ <groupId>org.yaml</groupId>
+ <artifactId>snakeyaml</artifactId>
+ <version>2.3</version>
+ </dependency>
+
+ <dependency>
+ <groupId>junit</groupId>
+ <artifactId>junit</artifactId>
+ <version>4.12</version>
+ <scope>test</scope>
+ </dependency>
+
+ </dependencies>
+
+ <build>
+ <plugins>
+ <plugin>
+ <groupId>org.apache.maven.plugins</groupId>
+ <artifactId>maven-compiler-plugin</artifactId>
+ <version>3.8.1</version>
+ <configuration>
+ <source>21</source>
+ <target>21</target>
+ <optimize>true</optimize>
+ <encoding>UTF-8</encoding>
+ </configuration>
+ </plugin>
+
+ <plugin>
+ <groupId>org.apache.maven.plugins</groupId>
+ <artifactId>maven-source-plugin</artifactId>
+ <version>2.2.1</version>
+ <executions>
+ <execution>
+ <id>attach-sources</id>
+ <goals>
+ <goal>jar</goal>
+ </goals>
+ </execution>
+ </executions>
+ </plugin>
+
+ <plugin>
+ <groupId>org.apache.maven.plugins</groupId>
+ <artifactId>maven-javadoc-plugin</artifactId>
+ <version>2.10.4</version>
+ <executions>
+ <execution>
+ <id>attach-javadocs</id>
+ <goals>
+ <goal>jar</goal>
+ </goals>
+ </execution>
+ </executions>
+ <configuration>
+ <!-- workaround for https://bugs.openjdk.java.net/browse/JDK-8212233 -->
+ <javaApiLinks>
+ <property>
+ <name>foo</name>
+ <value>bar</value>
+ </property>
+ </javaApiLinks>
+ <!-- Workaround for https://stackoverflow.com/questions/49472783/maven-is-unable-to-find-javadoc-command -->
+ <javadocExecutable>${java.home}/bin/javadoc</javadocExecutable>
+ </configuration>
+ </plugin>
+
+ <plugin>
+ <groupId>org.apache.maven.plugins</groupId>
+ <artifactId>maven-resources-plugin</artifactId>
+ <version>2.4.3</version>
+ <configuration>
+ <encoding>UTF-8</encoding>
+ </configuration>
+ </plugin>
+
+ <plugin>
+ <groupId>org.apache.maven.plugins</groupId>
+ <artifactId>maven-release-plugin</artifactId>
+ <version>2.5.2</version>
+ <dependencies>
+ <dependency>
+ <groupId>org.apache.maven.scm</groupId>
+ <artifactId>maven-scm-provider-gitexe</artifactId>
+ <version>1.9.4</version>
+ </dependency>
+ </dependencies>
+ </plugin>
+ </plugins>
+
+ <extensions>
+ <extension>
+ <groupId>org.apache.maven.wagon</groupId>
+ <artifactId>wagon-ssh-external</artifactId>
+ <version>2.6</version>
+ </extension>
+ </extensions>
+ </build>
+
+
+ <distributionManagement>
+ <snapshotRepository>
+ <id>svjatoslav.eu</id>
+ <name>svjatoslav.eu</name>
+ <url>scpexe://svjatoslav.eu:10006/srv/maven</url>
+ </snapshotRepository>
+ <repository>
+ <id>svjatoslav.eu</id>
+ <name>svjatoslav.eu</name>
+ <url>scpexe://svjatoslav.eu:10006/srv/maven</url>
+ </repository>
+ </distributionManagement>
+
+ <repositories>
+ <repository>
+ <id>svjatoslav.eu</id>
+ <name>Svjatoslav repository</name>
+ <url>https://www3.svjatoslav.eu/maven/</url>
+ </repository>
+ </repositories>
+
+ <scm>
+ <connection>scm:git:ssh://n0@svjatoslav.eu:10006/home/n0/git/aukio-3d.git</connection>
+ <developerConnection>scm:git:ssh://n0@svjatoslav.eu:10006/home/n0/git/aukio-3d.git</developerConnection>
+ <tag>HEAD</tag>
+ </scm>
+
+</project>
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.cfg;
+
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.nio.channels.FileChannel;
+import java.nio.channels.FileLock;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.AtomicMoveNotSupportedException;
+import java.nio.file.Files;
+import java.nio.file.NoSuchFileException;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.StandardCopyOption;
+import java.nio.file.StandardOpenOption;
+import java.nio.file.attribute.BasicFileAttributes;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.UUID;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.TimeUnit;
+
+import org.yaml.snakeyaml.DumperOptions;
+import org.yaml.snakeyaml.Yaml;
+import org.yaml.snakeyaml.error.YAMLException;
+
+/**
+ * Shared user configuration for the whole Aukio family (engine, workspace
+ * app, environments), stored as a single YAML file.
+ *
+ * <p>Default file: {@code ~/.config/aukio/config.yaml} (override with
+ * {@code -Daukio.config=<path>}; the legacy {@code -De3d.config=<path>}
+ * is honored as a fallback for engine-only tooling). A missing file
+ * means empty configuration — every getter falls back to its caller
+ * supplied default.</p>
+ *
+ * <p>Tenancy is by YAML section, flat camelCase keys per section:
+ * {@code e3d} (engine), {@code fo4} (Fallout 4 environment), {@code app}
+ * (workspace app; its {@code state} subtree is written by the app at
+ * runtime). Unknown keys in the file are preserved verbatim.</p>
+ *
+ * <p>Freshness: every getter checks the file's (mtime, size, fileKey)
+ * stamp and re-parses only when it changed, so hand edits made while an
+ * app is running become visible on the next read. Writes
+ * ({@code setString} and friends) lock a sidecar {@code <file>.lock},
+ * re-read the file under the lock, merge the new key, and atomically
+ * rename a temp file into place — a hand edit made between the writer's
+ * read and write survives. All cooperating processes must use this
+ * class; an editor saving a stale buffer over newer YAML is the one
+ * race no file format can solve (Emacs's changed-on-disk warning is
+ * the guard).</p>
+ *
+ * <p>Known limitation: SnakeYAML rewrites the file on the first
+ * {@code set}, so human-written header comments are not preserved
+ * through app writes — conventions live in each repo's AGENTS.org, not
+ * in the file.</p>
+ *
+ * <p>Instances are cached per resolved path in a per-JVM registry:
+ * {@link #get()} returns the same instance to every caller in this
+ * JVM (engine, workspace app, environments), so the stamp cache is
+ * shared. Separate JVMs each hold their own instance.</p>
+ */
+public final class AukioConfig {
+
+ /** Registry of instances keyed by normalized absolute path. */
+ private static final ConcurrentHashMap<String, AukioConfig> REGISTRY =
+ new ConcurrentHashMap<>();
+
+ /** Instance for the default file, honoring system property overrides. */
+ public static AukioConfig get() {
+ return forFile(System.getProperty("aukio.config",
+ System.getProperty("e3d.config",
+ System.getProperty("user.home")
+ + "/.config/aukio/config.yaml")));
+ }
+
+ /** Cached instance for the given file (same path → same instance). */
+ public static AukioConfig forFile(final String path) {
+ return forFile(Paths.get(path));
+ }
+
+ /** Cached instance for the given file (same path → same instance). */
+ public static AukioConfig forFile(final Path path) {
+ final Path key = path.toAbsolutePath().normalize();
+ return REGISTRY.computeIfAbsent(key.toString(),
+ k -> new AukioConfig(key));
+ }
+
+ private final Path file;
+ private final Object refreshMonitor = new Object();
+ private final Object writeMonitor = new Object();
+ private volatile Map<String, Object> snapshot;
+ private volatile Stamp stamp;
+
+ private AukioConfig(final Path file) {
+ this.file = file;
+ }
+
+ /** The file this instance reads and writes. */
+ public Path path() {
+ return file;
+ }
+
+ /** String value at the dotted path, or {@code fallback} when absent. */
+ public String getString(final String dottedPath, final String fallback) {
+ final Object value = navigate(current(), dottedPath);
+ return value == null ? fallback : String.valueOf(value);
+ }
+
+ /** Numeric value at the dotted path, or {@code fallback} when absent/unparseable. */
+ public double getDouble(final String dottedPath, final double fallback) {
+ return parseNumber(getString(dottedPath, null), fallback);
+ }
+
+ /** Numeric value at the dotted path truncated to int. */
+ public int getInt(final String dottedPath, final int fallback) {
+ return (int) parseNumber(getString(dottedPath, null), fallback);
+ }
+
+ /** Boolean value at the dotted path, or {@code fallback} when absent. */
+ public boolean getBoolean(final String dottedPath, final boolean fallback) {
+ final String value = getString(dottedPath, null);
+ return value == null ? fallback
+ : Boolean.parseBoolean(value.trim());
+ }
+
+ /**
+ * All scalar leaves under a section, flattened to dotted keys
+ * (e.g. the {@code fo4} section's {@code path} and {@code spawnAt}
+ * entries). Non-scalar values nested deeper are flattened too;
+ * absent section yields an empty map.
+ */
+ public Map<String, String> getStringMap(final String dottedPath) {
+ final Object value = navigate(current(), dottedPath);
+ if (!(value instanceof Map))
+ return Collections.emptyMap();
+ final Map<String, String> out = new LinkedHashMap<>();
+ flatten(castMap(value), "", out);
+ return Collections.unmodifiableMap(out);
+ }
+
+ /** Sets a string value, creating intermediate sections as needed. */
+ public void setString(final String dottedPath, final String value) {
+ writeMerge(dottedPath, value);
+ }
+
+ /** Sets an int value. */
+ public void setInt(final String dottedPath, final int value) {
+ writeMerge(dottedPath, Integer.valueOf(value));
+ }
+
+ /** Sets a double value. */
+ public void setDouble(final String dottedPath, final double value) {
+ writeMerge(dottedPath, Double.valueOf(value));
+ }
+
+ /** Sets a boolean value. */
+ public void setBoolean(final String dottedPath, final boolean value) {
+ writeMerge(dottedPath, Boolean.valueOf(value));
+ }
+
+ // ------------------------------------------------------------------
+ // reads
+ // ------------------------------------------------------------------
+
+ /** Current snapshot, refreshing from disk when the stamp changed. */
+ private Map<String, Object> current() {
+ Map<String, Object> snap = snapshot;
+ Stamp st = Stamp.of(file);
+ if (snap == null || !st.equals(stamp)) {
+ synchronized (refreshMonitor) {
+ snap = snapshot;
+ st = Stamp.of(file);
+ if (snap == null || !st.equals(stamp)) {
+ snap = freeze(load(file));
+ snapshot = snap;
+ stamp = st;
+ }
+ }
+ }
+ return snap;
+ }
+
+ private static Map<String, Object> load(final Path path) {
+ if (!Files.isRegularFile(path))
+ return new LinkedHashMap<>();
+ try {
+ final Object root = new Yaml().load(
+ Files.readString(path, StandardCharsets.UTF_8));
+ if (root instanceof Map)
+ return castMap(root);
+ } catch (final IOException e) {
+ System.err.println("[CONFIG] could not read " + path + ": "
+ + e.getMessage());
+ } catch (final YAMLException e) {
+ System.err.println("[CONFIG] could not parse " + path + ": "
+ + e.getMessage());
+ }
+ return new LinkedHashMap<>();
+ }
+
+ private static Object navigate(final Map<String, Object> root,
+ final String dottedPath) {
+ final String[] segments = dottedPath.split("\\.");
+ Map<String, Object> level = root;
+ for (int i = 0; i < segments.length - 1; i++) {
+ final Object next = level.get(segments[i]);
+ if (!(next instanceof Map))
+ return null;
+ level = castMap(next);
+ }
+ return level.get(segments[segments.length - 1]);
+ }
+
+ private static void flatten(final Map<String, Object> in,
+ final String prefix,
+ final Map<String, String> out) {
+ for (final Map.Entry<String, Object> e : in.entrySet()) {
+ final String key = prefix.isEmpty() ? e.getKey()
+ : prefix + "." + e.getKey();
+ if (e.getValue() instanceof Map)
+ flatten(castMap(e.getValue()), key, out);
+ else
+ out.put(key, String.valueOf(e.getValue()));
+ }
+ }
+
+ // ------------------------------------------------------------------
+ // writes
+ // ------------------------------------------------------------------
+
+ /**
+ * Locked read-merge-write: the lock sidecar serializes writers
+ * across JVMs; the fresh read under the lock folds in any hand
+ * edits made since our last snapshot; the temp file + atomic move
+ * keeps readers (which never lock) from ever seeing torn content.
+ */
+ private void writeMerge(final String dottedPath, final Object value) {
+ final Path lockFile = file.resolveSibling(
+ file.getFileName() + ".lock");
+ try {
+ final Path parent = file.getParent();
+ if (parent != null)
+ Files.createDirectories(parent);
+ // FileLock serializes writers across JVMs but throws
+ // OverlappingFileLockException for threads of the same JVM,
+ // so writers of this instance first exclude each other here.
+ synchronized (writeMonitor) {
+ try (FileChannel channel = FileChannel.open(lockFile,
+ StandardOpenOption.CREATE, StandardOpenOption.WRITE);
+ FileLock ignored = channel.lock()) {
+ final Map<String, Object> data = load(file);
+ merge(data, dottedPath.split("\\."), 0, value);
+ final byte[] bytes = dump(data)
+ .getBytes(StandardCharsets.UTF_8);
+ final Path tmp = file.resolveSibling(
+ file.getFileName() + ".tmp-"
+ + UUID.randomUUID());
+ Files.write(tmp, bytes, StandardOpenOption.CREATE,
+ StandardOpenOption.TRUNCATE_EXISTING);
+ try {
+ Files.move(tmp, file,
+ StandardCopyOption.ATOMIC_MOVE,
+ StandardCopyOption.REPLACE_EXISTING);
+ } catch (final AtomicMoveNotSupportedException e) {
+ Files.move(tmp, file,
+ StandardCopyOption.REPLACE_EXISTING);
+ }
+ snapshot = freeze(data);
+ stamp = Stamp.of(file);
+ }
+ }
+ } catch (final IOException e) {
+ throw new UncheckedIOException("could not write " + file, e);
+ }
+ }
+
+ private static void merge(final Map<String, Object> level,
+ final String[] segments, final int index,
+ final Object value) {
+ if (index == segments.length - 1) {
+ level.put(segments[index], value);
+ return;
+ }
+ final Object next = level.get(segments[index]);
+ final Map<String, Object> child;
+ if (next instanceof Map) {
+ child = castMap(next);
+ } else {
+ child = new LinkedHashMap<>();
+ level.put(segments[index], child);
+ }
+ merge(child, segments, index + 1, value);
+ }
+
+ private static String dump(final Map<String, Object> data) {
+ final DumperOptions options = new DumperOptions();
+ options.setDefaultFlowStyle(DumperOptions.FlowStyle.BLOCK);
+ options.setPrettyFlow(true);
+ return new Yaml(options).dump(data);
+ }
+
+ // ------------------------------------------------------------------
+ // snapshot immutability
+ // ------------------------------------------------------------------
+
+ private static Map<String, Object> freeze(final Map<String, Object> in) {
+ final Map<String, Object> out = new LinkedHashMap<>();
+ for (final Map.Entry<String, Object> e : in.entrySet()) {
+ final Object value = e.getValue();
+ if (value instanceof Map)
+ out.put(e.getKey(), freeze(castMap(value)));
+ else if (value instanceof List)
+ out.put(e.getKey(), freezeList(castList(value)));
+ else
+ out.put(e.getKey(), value);
+ }
+ return Collections.unmodifiableMap(out);
+ }
+
+ private static List<Object> freezeList(final List<Object> in) {
+ final List<Object> out = new ArrayList<>(in.size());
+ for (final Object value : in) {
+ if (value instanceof Map)
+ out.add(freeze(castMap(value)));
+ else if (value instanceof List)
+ out.add(freezeList(castList(value)));
+ else
+ out.add(value);
+ }
+ return Collections.unmodifiableList(out);
+ }
+
+ // ------------------------------------------------------------------
+ // small helpers
+ // ------------------------------------------------------------------
+
+ private static double parseNumber(final String value,
+ final double fallback) {
+ if (value == null || value.isBlank())
+ return fallback;
+ try {
+ return Double.parseDouble(value.trim());
+ } catch (final NumberFormatException e) {
+ return fallback;
+ }
+ }
+
+ @SuppressWarnings("unchecked")
+ private static Map<String, Object> castMap(final Object map) {
+ return (Map<String, Object>) map;
+ }
+
+ @SuppressWarnings("unchecked")
+ private static List<Object> castList(final Object list) {
+ return (List<Object>) list;
+ }
+
+ /** Identity of a file's content for freshness checks. */
+ private static final class Stamp {
+ private static final Stamp MISSING = new Stamp(-1, -1, null);
+
+ private final long mtimeNanos;
+ private final long size;
+ private final Object fileKey;
+
+ private Stamp(final long mtimeNanos, final long size,
+ final Object fileKey) {
+ this.mtimeNanos = mtimeNanos;
+ this.size = size;
+ this.fileKey = fileKey;
+ }
+
+ static Stamp of(final Path path) {
+ try {
+ final BasicFileAttributes attrs = Files.readAttributes(path,
+ BasicFileAttributes.class);
+ return new Stamp(
+ attrs.lastModifiedTime().to(TimeUnit.NANOSECONDS),
+ attrs.size(), attrs.fileKey());
+ } catch (final NoSuchFileException e) {
+ return MISSING;
+ } catch (final IOException e) {
+ return new Stamp(-2, -2, null);
+ }
+ }
+
+ @Override
+ public boolean equals(final Object other) {
+ if (this == other)
+ return true;
+ if (!(other instanceof Stamp))
+ return false;
+ final Stamp o = (Stamp) other;
+ return mtimeNanos == o.mtimeNanos && size == o.size
+ && java.util.Objects.equals(fileKey, o.fileKey);
+ }
+
+ @Override
+ public int hashCode() {
+ return java.util.Objects.hash(mtimeNanos, size, fileKey);
+ }
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+/**
+ * Shared YAML-backed configuration for the whole Aukio family
+ * (engine, workspace app, environments): one file, per-section
+ * tenancy, mtime-checked freshness, locked atomic writes. See
+ * {@link eu.svjatoslav.aukio.cfg.AukioConfig}.
+ */
+package eu.svjatoslav.aukio.cfg;
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.diag;
+
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Circular buffer for debug log messages.
+ *
+ * <p>Captures log messages to a fixed-size circular buffer for display
+ * in the {@link eu.svjatoslav.aukio.e3d.gui.DeveloperToolsPanel}.</p>
+ *
+ * <p>This allows capturing early initialization logs before the user opens
+ * the Developer Tools panel. When the panel is opened, the buffered history
+ * becomes immediately visible.</p>
+ *
+ * @see eu.svjatoslav.aukio.e3d.gui.DeveloperToolsPanel
+ */
+public class DebugLogBuffer {
+
+ private static final DateTimeFormatter TIME_FORMATTER =
+ DateTimeFormatter.ofPattern("HH:mm:ss.SSS");
+
+ private final String[] buffer;
+ private final int capacity;
+ private volatile int head = 0;
+ private volatile int count = 0;
+
+ /**
+ * Creates a new DebugLogBuffer with the specified capacity.
+ *
+ * @param capacity the maximum number of log entries to retain
+ */
+ public DebugLogBuffer(final int capacity) {
+ this.capacity = capacity;
+ this.buffer = new String[capacity];
+ }
+
+ /**
+ * Logs a message with a timestamp prefix.
+ *
+ * @param message the message to log
+ */
+ public void log(final String message) {
+ final String timestamped = LocalDateTime.now().format(TIME_FORMATTER) + " " + message;
+
+ synchronized (this) {
+ buffer[head] = timestamped;
+ head = (head + 1) % capacity;
+ if (count < capacity) {
+ count++;
+ }
+ }
+ }
+
+ /**
+ * Returns all buffered log entries in chronological order.
+ *
+ * @return a list of timestamped log entries
+ */
+ public synchronized List<String> getEntries() {
+ final List<String> entries = new ArrayList<>(count);
+
+ if (count < capacity) {
+ for (int i = 0; i < count; i++) {
+ entries.add(buffer[i]);
+ }
+ } else {
+ for (int i = 0; i < capacity; i++) {
+ final int index = (head + i) % capacity;
+ entries.add(buffer[index]);
+ }
+ }
+
+ return entries;
+ }
+
+ /**
+ * Clears all buffered log entries.
+ */
+ public synchronized void clear() {
+ head = 0;
+ count = 0;
+ }
+
+ /**
+ * Returns the current number of log entries in the buffer.
+ *
+ * @return the number of entries
+ */
+ public synchronized int size() {
+ return count;
+ }
+}
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.diag;
+
+/**
+ * Facade that wires up Aukio diagnostics: persistent rolling log plus the
+ * periodic telemetry line.
+ *
+ * <p>Installed automatically when the first {@code ViewPanel} is created,
+ * or explicitly at application startup ({@code Diagnostics.install()} as
+ * the first statement of {@code main()}) so early boot output is captured
+ * too. Disable entirely with {@code -De3d.diagnostics=false}.</p>
+ */
+public final class Diagnostics {
+
+ private static volatile boolean installed = false;
+
+ private Diagnostics() {
+ }
+
+ /** Installs persistent logging and starts telemetry. Idempotent. */
+ public static synchronized void install() {
+ if (installed)
+ return;
+ installed = true;
+ if ("false".equalsIgnoreCase(
+ System.getProperty("e3d.diagnostics", "true"))) {
+ System.out.println("[DIAG] diagnostics disabled"
+ + " (e3d.diagnostics=false)");
+ return;
+ }
+ PersistentLog.install();
+ Telemetry.start();
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.diag;
+
+import eu.svjatoslav.aukio.cfg.AukioConfig;
+
+import java.io.File;
+
+/**
+ * User configuration for Aukio 3D engine settings. Thin facade over
+ * {@link AukioConfig}: engine keys live in the {@code e3d} section of
+ * {@code ~/.config/aukio/config.yaml} (override the file with
+ * {@code -Daukio.config=<path>}; the legacy {@code -De3d.config=<path>}
+ * is honored as a fallback). A missing file or key means built-in
+ * defaults.
+ *
+ * <p>Recognized keys (flat camelCase inside the {@code e3d} section):
+ * {@code ipdCm} — interpupillary distance in centimeters for
+ * stereoscopic (3D glasses) rendering, default 6.5; {@code bugReportDir}
+ * — directory under which bug reports are written, default
+ * {@code ~/.local/share/aukio/bugreports}; {@code logDir} — directory
+ * for persistent rolling logs, default {@code ~/.cache/aukio/logs};
+ * {@code telemetryIntervalSeconds} — how often the telemetry line is
+ * written to the log, default 5.</p>
+ *
+ * <p>Every key can also be set as a system property
+ * ({@code -De3d.ipd=6.3}, {@code -De3d.bugreport.dir=...},
+ * {@code -De3d.log.dir=...}, {@code -De3d.telemetry.interval=...});
+ * system properties win over the config file.</p>
+ */
+public final class EngineConfig {
+
+ /** Default stereo IPD in world units (centimeters). */
+ public static final double DEFAULT_IPD_CM = 6.5;
+
+ private EngineConfig() {
+ }
+
+ /**
+ * Interpupillary distance for stereo rendering, in world units
+ * (centimeters).
+ */
+ public static double getIpdCm() {
+ return parseDouble(System.getProperty("e3d.ipd",
+ AukioConfig.get().getString("e3d.ipdCm", null)),
+ DEFAULT_IPD_CM);
+ }
+
+ /** Directory under which bug reports are written. */
+ public static File getBugReportDir() {
+ return new File(expandHome(System.getProperty("e3d.bugreport.dir",
+ AukioConfig.get().getString("e3d.bugReportDir",
+ "~/.local/share/aukio/bugreports"))));
+ }
+
+ /** Directory for persistent rolling logs. */
+ public static File getLogDir() {
+ return new File(expandHome(System.getProperty("e3d.log.dir",
+ AukioConfig.get().getString("e3d.logDir",
+ "~/.cache/aukio/logs"))));
+ }
+
+ /** Telemetry write interval, seconds. */
+ public static int getTelemetryIntervalSeconds() {
+ return (int) parseDouble(System.getProperty("e3d.telemetry.interval",
+ AukioConfig.get().getString("e3d.telemetryIntervalSeconds",
+ null)), 5);
+ }
+
+ private static double parseDouble(final String value,
+ final double fallback) {
+ if (value == null || value.isBlank())
+ return fallback;
+ try {
+ return Double.parseDouble(value.trim());
+ } catch (final NumberFormatException e) {
+ return fallback;
+ }
+ }
+
+ private static String expandHome(final String path) {
+ if (path.startsWith("~/"))
+ return System.getProperty("user.home") + path.substring(1);
+ return path;
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.diag;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.PrintStream;
+import java.nio.file.Files;
+import java.nio.file.StandardCopyOption;
+
+/**
+ * Persistent rolling log: tees {@code System.out} and {@code System.err}
+ * into a log file on disk so a hung or crashed session still leaves its
+ * full output behind.
+ *
+ * <p>The file lives at {@code <logDir>/aukio.log} and is rotated to
+ * {@code aukio.log.1} (one backup kept) once it exceeds
+ * {@value #MAX_LOG_BYTES}. Writes are flushed per line so the last output
+ * before an OutOfMemory freeze is on disk even when the application can
+ * no longer react to window events.</p>
+ *
+ * @see Diagnostics
+ */
+public final class PersistentLog {
+
+ /** Rotate the log once it exceeds this size. */
+ private static final long MAX_LOG_BYTES = 4L * 1024 * 1024;
+
+ private static volatile boolean installed = false;
+ private static volatile File logFile;
+
+ private PersistentLog() {
+ }
+
+ /**
+ * Installs the tee. Idempotent; failures (unwritable directory) fall
+ * back to console-only logging and are reported on stderr.
+ */
+ public static synchronized void install() {
+ if (installed)
+ return;
+ installed = true;
+
+ final File dir = EngineConfig.getLogDir();
+ try {
+ Files.createDirectories(dir.toPath());
+ logFile = new File(dir, "aukio.log");
+ final SharedFileOutput shared = new SharedFileOutput(logFile);
+ System.setOut(new PrintStream(
+ new TeeStream(System.out, shared), true));
+ System.setErr(new PrintStream(
+ new TeeStream(System.err, shared), true));
+ System.out.println("[LOG] persistent log: "
+ + logFile.getAbsolutePath());
+ } catch (final IOException e) {
+ System.err.println("[LOG] persistent logging unavailable in "
+ + dir + ": " + e.getMessage());
+ logFile = null;
+ }
+ }
+
+ /** The current log file, or null when persistent logging failed. */
+ public static File getLogFile() {
+ return logFile;
+ }
+
+ /**
+ * Single shared append stream to the log file; both the stdout and
+ * stderr tees write through it. Rotates the file once it grows past
+ * {@link #MAX_LOG_BYTES}.
+ */
+ private static final class SharedFileOutput {
+
+ private final File file;
+ private OutputStream out;
+
+ SharedFileOutput(final File file) throws IOException {
+ this.file = file;
+ this.out = new FileOutputStream(file, true);
+ }
+
+ synchronized void write(final int b) throws IOException {
+ rotateIfNeeded();
+ out.write(b);
+ if (b == '\n')
+ out.flush();
+ }
+
+ synchronized void write(final byte[] b, final int off,
+ final int len) throws IOException {
+ rotateIfNeeded();
+ out.write(b, off, len);
+ out.flush();
+ }
+
+ private void rotateIfNeeded() throws IOException {
+ if (file.length() < MAX_LOG_BYTES)
+ return;
+ out.close();
+ final File backup = new File(file.getParentFile(),
+ file.getName() + ".1");
+ Files.move(file.toPath(), backup.toPath(),
+ StandardCopyOption.REPLACE_EXISTING);
+ out = new FileOutputStream(file, true);
+ }
+ }
+
+ /** Mirrors writes to the console and to the shared log file. */
+ private static final class TeeStream extends OutputStream {
+
+ private final PrintStream console;
+ private final SharedFileOutput file;
+
+ TeeStream(final PrintStream console, final SharedFileOutput file) {
+ this.console = console;
+ this.file = file;
+ }
+
+ @Override
+ public void write(final int b) throws IOException {
+ console.write(b);
+ file.write(b);
+ }
+
+ @Override
+ public void write(final byte[] b, final int off, final int len)
+ throws IOException {
+ console.write(b, off, len);
+ file.write(b, off, len);
+ }
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.diag;
+
+import java.lang.management.ManagementFactory;
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.function.Supplier;
+
+/**
+ * Periodic telemetry line written to the persistent log: heap usage plus
+ * whatever counters registered subsystems report (streaming caches,
+ * loaded cells, queue depths, measured FPS...).
+ *
+ * <p>Slowdown-toward-OOM issues show up here as a monotonic climb in one
+ * of the numbers across a flight, which names the leaking resource. The
+ * line is written every {@code telemetry.interval.seconds} (default 5)
+ * and goes to stdout — the {@link PersistentLog} tee puts it on disk even
+ * when the application later freezes.</p>
+ */
+public final class Telemetry {
+
+ private static final DateTimeFormatter TIME_FORMATTER =
+ DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
+
+ private static final Map<String, Supplier<String>> SOURCES =
+ new ConcurrentHashMap<>();
+
+ private static volatile boolean started = false;
+
+ private Telemetry() {
+ }
+
+ /**
+ * Registers a named telemetry source. The supplier must be fast and
+ * side-effect free; it runs on the telemetry thread. Registering the
+ * same name again replaces the previous source.
+ *
+ * @param name short subsystem name, e.g. {@code "fo4"}
+ * @param source produces a compact stats string, e.g.
+ * {@code "cells=12 tris=450000"}
+ */
+ public static void registerSource(final String name,
+ final Supplier<String> source) {
+ SOURCES.put(name, source);
+ }
+
+ /** Removes a previously registered source (subsystem shutdown). */
+ public static void unregisterSource(final String name) {
+ SOURCES.remove(name);
+ }
+
+ /** Starts the daemon telemetry thread. Idempotent. */
+ public static synchronized void start() {
+ if (started)
+ return;
+ started = true;
+ final int intervalSeconds =
+ Math.max(1, EngineConfig.getTelemetryIntervalSeconds());
+ final Thread thread = new Thread(() -> {
+ while (true) {
+ try {
+ Thread.sleep(intervalSeconds * 1000L);
+ } catch (final InterruptedException e) {
+ return;
+ }
+ try {
+ System.out.println(snapshotLine());
+ } catch (final Throwable t) {
+ // telemetry must never take the application down
+ }
+ }
+ }, "aukio-telemetry");
+ thread.setDaemon(true);
+ thread.start();
+ }
+
+ /**
+ * Builds the current telemetry line. Also used by bug reports to
+ * include a final snapshot.
+ */
+ public static String snapshotLine() {
+ final Runtime rt = Runtime.getRuntime();
+ final long used = rt.totalMemory() - rt.freeMemory();
+ final StringBuilder sb = new StringBuilder("TELEMETRY ");
+ sb.append(LocalDateTime.now().format(TIME_FORMATTER));
+ sb.append(String.format(" heap=%dM/%dM threads=%d",
+ used / (1024 * 1024), rt.maxMemory() / (1024 * 1024),
+ ManagementFactory.getThreadMXBean().getThreadCount()));
+ for (final Map.Entry<String, Supplier<String>> entry
+ : SOURCES.entrySet()) {
+ try {
+ sb.append(' ').append(entry.getKey()).append("={")
+ .append(entry.getValue().get()).append('}');
+ } catch (final Throwable t) {
+ sb.append(' ').append(entry.getKey()).append("={error}");
+ }
+ }
+ return sb.toString();
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.diag;
+
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * Low-overhead recorder of per-thread work intervals for the thread
+ * timeline display in the Developer Tools window.
+ *
+ * <p>Task submission sites (transform chunks, paint tiles, tile binning)
+ * and render-thread phases (orchestration, waiting, blit) record their
+ * [start, end) intervals here when enabled. The timeline component paints
+ * each thread as a row, time on the X axis, the interval kind as color —
+ * the software-renderer equivalent of a GPU frame-profiler occupancy
+ * view. Idle time is simply the absence of intervals (black).</p>
+ *
+ * <p>Overhead when disabled: one volatile read per task. When enabled:
+ * two {@code System.nanoTime()} calls, one atomic increment and four
+ * array stores per task (~100 ns), negligible at hundreds of tasks per
+ * frame.</p>
+ *
+ * <p>Frame parity distinguishes "current frame" work from "next frame"
+ * work in the colors: transform/paint/binning kinds come in an even and
+ * an odd variant, selected by the parity that was current when the task
+ * was SUBMITTED (captured at task creation, so overlapping frames keep
+ * their own color).</p>
+ */
+public final class ThreadActivityRecorder {
+
+ /** Kind base: vertex transform chunk (add frame parity 0..2). */
+ public static final int KIND_TRANSFORM = 0;
+ /** Kind base: paint tile task (add frame parity 0..2). */
+ public static final int KIND_PAINT = 3;
+ /** Kind base: tile binning task (add frame parity 0..2). */
+ public static final int KIND_BIN = 6;
+ /** Kind: render thread orchestration (tree walk, submission, merges). */
+ public static final int KIND_RENDER = 9;
+ /** Kind: render thread blocked waiting for worker tasks. */
+ public static final int KIND_AWAIT = 10;
+ /** Kind: render thread blitting the finished frame to screen. */
+ public static final int KIND_BLIT = 11;
+ /** Kind: a pass's asynchronous continuation (drain, sort, bin, paint submission). */
+ public static final int KIND_PREP = 12;
+ /** Kind: continuation sub-phase: draining and merging transform chunks. */
+ public static final int KIND_DRAIN = 13;
+ /** Kind: continuation sub-phase: depth sort. */
+ public static final int KIND_SORT = 14;
+
+ /** Number of distinct kinds (three parities each for transform/paint/bin, plus 9..14). */
+ public static final int KIND_COUNT = 15;
+
+ private static final int CAPACITY = 1 << 18;
+ private static final int MASK = CAPACITY - 1;
+
+ private static final long[] starts = new long[CAPACITY];
+ private static final long[] ends = new long[CAPACITY];
+ private static final byte[] kinds = new byte[CAPACITY];
+ private static final byte[] rows = new byte[CAPACITY];
+ private static final AtomicInteger cursor = new AtomicInteger();
+
+ private static volatile boolean enabled = false;
+ private static volatile int frameParity = 0;
+
+ private static final ConcurrentHashMap<String, Integer> rowByThreadName = new ConcurrentHashMap<>();
+ private static final CopyOnWriteArrayList<String> rowNames = new CopyOnWriteArrayList<>();
+ private static final AtomicInteger nextRow = new AtomicInteger();
+
+ private ThreadActivityRecorder() {
+ }
+
+ /**
+ * @return true when recording is active (checked by task submission sites)
+ */
+ public static boolean isEnabled() {
+ return enabled;
+ }
+
+ /**
+ * Enables or disables recording. Enabling starts with a clean buffer
+ * and fresh thread-row assignment.
+ *
+ * @param value true to start recording
+ */
+ public static void setEnabled(final boolean value) {
+ if (value && !enabled) {
+ clear();
+ }
+ enabled = value;
+ }
+
+ /**
+ * Drops all recorded intervals and thread-row assignments.
+ */
+ public static void clear() {
+ cursor.set(0);
+ rowByThreadName.clear();
+ rowNames.clear();
+ nextRow.set(0);
+ // starts[]==0 marks an empty slot for the timeline sweep
+ java.util.Arrays.fill(starts, 0L);
+ }
+
+ /**
+ * Sets the parity (0/1) of the frame currently being prepared.
+ * Called by the render thread at the start of each frame; task
+ * submission sites capture it into their tasks so overlapping frames
+ * keep distinct colors.
+ *
+ * @param parity frame parity, 0 or 1
+ */
+ public static void setFrameParity(final int parity) {
+ frameParity = parity;
+ }
+
+ /**
+ * @return parity of the frame currently being prepared
+ */
+ public static int frameParity() {
+ return frameParity;
+ }
+
+ /**
+ * Records one work interval on the calling thread.
+ *
+ * @param kind interval kind (one of the KIND_* bases, plus parity
+ * for transform/paint/binning)
+ * @param t0 interval start, from {@link System#nanoTime()}
+ * @param t1 interval end, from {@link System#nanoTime()}
+ */
+ public static void record(final int kind, final long t0, final long t1) {
+ // Rows are keyed by thread NAME, not Thread object: after a
+ // stop()/start() cycle the executor is recreated with fresh
+ // threads under the same names, and they must reuse the same
+ // rows — otherwise the timeline fills with dead threads' rows
+ // and pushes the live workers below the visible area.
+ final String threadName = Thread.currentThread().getName();
+ Integer row = rowByThreadName.get(threadName);
+ if (row == null) {
+ row = rowByThreadName.computeIfAbsent(threadName, t -> {
+ final int r = nextRow.getAndIncrement();
+ rowNames.add(t);
+ return r;
+ });
+ }
+ if (row > 127) {
+ return;
+ }
+ final int i = cursor.getAndIncrement() & MASK;
+ starts[i] = t0;
+ ends[i] = t1;
+ kinds[i] = (byte) kind;
+ rows[i] = (byte) (int) row;
+ }
+
+ // ---- Snapshot access for the timeline component ----
+
+ /** @return total number of intervals recorded since the last clear */
+ public static int cursor() {
+ return cursor.get();
+ }
+
+ /** @return ring buffer capacity */
+ public static int capacity() {
+ return CAPACITY;
+ }
+
+ /** @return interval start array (index space of the ring buffer) */
+ public static long[] starts() {
+ return starts;
+ }
+
+ /** @return interval end array (index space of the ring buffer) */
+ public static long[] ends() {
+ return ends;
+ }
+
+ /** @return interval kind array (index space of the ring buffer) */
+ public static byte[] kinds() {
+ return kinds;
+ }
+
+ /** @return interval thread-row array (index space of the ring buffer) */
+ public static byte[] rows() {
+ return rows;
+ }
+
+ /** @return number of distinct thread rows seen so far */
+ public static int rowCount() {
+ return nextRow.get();
+ }
+
+ /**
+ * @param row thread row index
+ * @return display name for the row ("render" for the render thread,
+ * otherwise the thread name with the e3d- prefix stripped)
+ */
+ public static String rowName(final int row) {
+ if (row >= rowNames.size()) {
+ return "?";
+ }
+ final String name = rowNames.get(row);
+ if ("e3d-render".equals(name)) {
+ return "render";
+ }
+ return name.startsWith("e3d-") ? name.substring(4) : name;
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.geometry;
+
+import static java.lang.Math.abs;
+
+/**
+ * A 3D axis-aligned bounding box defined by two corner points.
+ *
+ * <p>Also known as: 3D rectangle, rectangular box, rectangular parallelepiped,
+ * cuboid, rhomboid, hexahedron, or rectangular prism.</p>
+ *
+ * <p>The box is defined by two points ({@link #p1} and {@link #p2}) that represent
+ * opposite corners. The box does not enforce ordering of these points.</p>
+ *
+ * <p><b>Example usage:</b></p>
+ * <pre>{@code
+ * Box box = new Box(new Point3D(0, 0, 0), new Point3D(100, 50, 200));
+ * double volume = box.getWidth() * box.getHeight() * box.getDepth();
+ * box.enlarge(10); // expand by 10 units in all directions
+ * }</pre>
+ *
+ * @see Point3D
+ */
+public class Box implements Cloneable {
+
+ /**
+ * The first corner point of the box.
+ */
+ public final Point3D p1;
+ /**
+ * The second corner point of the box (opposite corner from p1).
+ */
+ public final Point3D p2;
+
+ /**
+ * Creates a new box with both corner points at the origin.
+ */
+ public Box() {
+ p1 = new Point3D();
+ p2 = new Point3D();
+ }
+
+ /**
+ * Creates a new box with the specified corner points.
+ *
+ * @param p1 the first corner point
+ * @param p2 the second corner point (opposite corner)
+ */
+ public Box(final Point3D p1, final Point3D p2) {
+ this.p1 = p1;
+ this.p2 = p2;
+ }
+
+
+ /**
+ * Enlarges the box by the specified border in all directions.
+ *
+ * @param border The border to enlarge the box by.
+ * If the border is negative, the box will be shrunk.
+ * @return The current box.
+ */
+ public Box enlarge(final double border) {
+
+ if (p1.x < p2.x) {
+ p1.translateX(-border);
+ p2.translateX(border);
+ } else {
+ p1.translateX(border);
+ p2.translateX(-border);
+ }
+
+ if (p1.y < p2.y) {
+ p1.translateY(-border);
+ p2.translateY(border);
+ } else {
+ p1.translateY(border);
+ p2.translateY(-border);
+ }
+
+ if (p1.z < p2.z) {
+ p1.translateZ(-border);
+ p2.translateZ(border);
+ } else {
+ p1.translateZ(border);
+ p2.translateZ(-border);
+ }
+
+ return this;
+ }
+
+ /**
+ * Creates a copy of this box with cloned corner points.
+ *
+ * @return a new box with the same corner coordinates
+ */
+ @Override
+ public Box clone() {
+ return new Box(p1.clone(), p2.clone());
+ }
+
+ /**
+ * Returns the depth of the box (distance along the Z-axis).
+ *
+ * @return the depth (always positive)
+ */
+ public double getDepth() {
+ return abs(p1.z - p2.z);
+ }
+
+ /**
+ * Returns the height of the box (distance along the Y-axis).
+ *
+ * @return the height (always positive)
+ */
+ public double getHeight() {
+ return abs(p1.y - p2.y);
+ }
+
+ /**
+ * Returns the width of the box (distance along the X-axis).
+ *
+ * @return the width (always positive)
+ */
+ public double getWidth() {
+ return abs(p1.x - p2.x);
+ }
+
+
+ /**
+ * Sets the size of the box. The box will be centered at the origin.
+ * Previous size and position of the box will be lost.
+ *
+ * @param size {@link Point3D} specifies box size in x, y and z axis.
+ */
+ public void setBoxSize(final Point3D size) {
+ p2.clone(size).divide(2);
+ p1.clone(p2).negate();
+ }
+
+ /**
+ * Returns the minimum X coordinate of this box.
+ * Useful for AABB intersection tests.
+ *
+ * @return the smaller X value of p1 and p2
+ */
+ public double getMinX() {
+ return Math.min(p1.x, p2.x);
+ }
+
+ /**
+ * Returns the maximum X coordinate of this box.
+ * Useful for AABB intersection tests.
+ *
+ * @return the larger X value of p1 and p2
+ */
+ public double getMaxX() {
+ return Math.max(p1.x, p2.x);
+ }
+
+ /**
+ * Returns the minimum Y coordinate of this box.
+ * Useful for AABB intersection tests.
+ *
+ * @return the smaller Y value of p1 and p2
+ */
+ public double getMinY() {
+ return Math.min(p1.y, p2.y);
+ }
+
+ /**
+ * Returns the maximum Y coordinate of this box.
+ * Useful for AABB intersection tests.
+ *
+ * @return the larger Y value of p1 and p2
+ */
+ public double getMaxY() {
+ return Math.max(p1.y, p2.y);
+ }
+
+ /**
+ * Returns the minimum Z coordinate of this box.
+ * Useful for AABB intersection tests.
+ *
+ * @return the smaller Z value of p1 and p2
+ */
+ public double getMinZ() {
+ return Math.min(p1.z, p2.z);
+ }
+
+ /**
+ * Returns the maximum Z coordinate of this box.
+ * Useful for AABB intersection tests.
+ *
+ * @return the larger Z value of p1 and p2
+ */
+ public double getMaxZ() {
+ return Math.max(p1.z, p2.z);
+ }
+
+ /**
+ * Returns the geometric center of this box.
+ *
+ * @return a new Point3D at the center of the box
+ */
+ public Point3D getCenter() {
+ return new Point3D(
+ (p1.x + p2.x) / 2.0,
+ (p1.y + p2.y) / 2.0,
+ (p1.z + p2.z) / 2.0
+ );
+ }
+
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.geometry;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.math.Matrix3x3;
+import eu.svjatoslav.aukio.e3d.math.Quaternion;
+import eu.svjatoslav.aukio.e3d.math.Transform;
+
+/**
+ * Represents the viewer's camera in the 3D world, with position, orientation, and movement.
+ *
+ * <p>The camera is the user's "eyes" in the 3D scene. It has a position (location),
+ * a looking direction (defined by a quaternion), and a movement system with
+ * velocity, acceleration, and friction for smooth camera navigation.</p>
+ *
+ * <p>By default, the user can navigate using arrow keys (handled by
+ * {@link eu.svjatoslav.aukio.e3d.gui.humaninput.WorldNavigationUserInputTracker}),
+ * and the mouse controls the look direction (handled by
+ * {@link eu.svjatoslav.aukio.e3d.gui.humaninput.InputManager}).</p>
+ *
+ * <p><b>Programmatic camera control:</b></p>
+ * <pre>{@code
+ * Camera camera = viewPanel.getCamera();
+ *
+ * // Set camera position
+ * camera.getTransform().setTranslation(new Point3D(0, -50, -200));
+ *
+ * // Set camera orientation using a quaternion
+ * camera.getTransform().getRotation().set(Quaternion.fromAngles(0.5, -0.3));
+ *
+ * // Copy camera state from another camera
+ * Camera snapshot = new Camera(camera);
+ * }</pre>
+ *
+ * @see eu.svjatoslav.aukio.e3d.gui.ViewPanel#getCamera()
+ * @see eu.svjatoslav.aukio.e3d.gui.humaninput.WorldNavigationUserInputTracker default keyboard navigation
+ */
+public class Camera {
+
+ /**
+ * Camera movement speed limit, relative to the world. When camera coordinates are
+ * updated within the world, camera orientation relative to the world is
+ * taken into account.
+ */
+ public static final double SPEED_LIMIT = 30;
+
+ /** World units moved per millisecond per unit of velocity.
+ * Public: direct-drive controllers (SpaceMouse) reuse it to match
+ * the keyboard/mouse feel. */
+ public static final double SPEED_MULTIPLIER = .02d;
+ /**
+ * Determines amount of friction user experiences every millisecond while moving around in space.
+ */
+ private static final double MILLISECOND_FRICTION = 1.005;
+ /**
+ * Camera movement speed, relative to camera itself. When camera coordinates
+ * are updated within the world, camera orientation relative to the world is
+ * taken into account.
+ */
+ private final Point3D movementVector = new Point3D();
+ private final Point3D previousLocation = new Point3D();
+ /**
+ * Camera acceleration factor for movement speed. Higher values result in faster acceleration.
+ */
+ public double cameraAcceleration = 0.1;
+ /**
+ * The transform containing camera location and orientation.
+ */
+ private final Transform transform;
+
+ /**
+ * Creates a camera at the world origin with no rotation.
+ */
+ public Camera() {
+ transform = new Transform();
+ }
+
+ /**
+ * Creates a copy of an existing camera, cloning its position and orientation.
+ *
+ * @param sourceView the camera to copy
+ */
+ public Camera(final Camera sourceView) {
+ transform = sourceView.getTransform().clone();
+ }
+
+ /**
+ * Creates a camera with the specified transform (position and orientation).
+ *
+ * @param transform the initial transform defining position and rotation
+ */
+ public Camera(final Transform transform){
+ this.transform = transform;
+ }
+
+ /**
+ * Per-frame camera physics tick (movement integration, friction).
+ * Registered on the panel via a {@code FrameListener} adapter in
+ * {@code ViewPanel} — decoupled from the gui interface so the camera
+ * stays in the geometry package.
+ *
+ * @param millisecondsSinceLastFrame frame delta in milliseconds
+ * @return true when the camera moved enough to need a repaint
+ */
+ public boolean onFrame(final int millisecondsSinceLastFrame) {
+
+ previousLocation.clone(transform.getTranslation());
+ translateCameraLocationBasedOnMovementVector(millisecondsSinceLastFrame);
+ applyFrictionToMovement(millisecondsSinceLastFrame);
+ return isFrameRepaintNeeded();
+ }
+
+ private boolean isFrameRepaintNeeded() {
+ final double distanceMoved = transform.getTranslation().getDistanceTo(previousLocation);
+ return distanceMoved > 0.03;
+ }
+
+ /**
+ * Clamps the camera's movement speed to {@link #SPEED_LIMIT}.
+ * Called after modifying the movement vector to prevent excessive velocity.
+ */
+ public void enforceSpeedLimit() {
+ final double currentSpeed = movementVector.getVectorLength();
+
+ if (currentSpeed <= SPEED_LIMIT)
+ return;
+
+ movementVector.divide(currentSpeed / SPEED_LIMIT);
+ }
+
+ /**
+ * Returns the current movement velocity vector, relative to the camera's orientation.
+ * Modify this vector to programmatically move the camera.
+ *
+ * @return the movement vector (mutable reference)
+ */
+ public Point3D getMovementVector() {
+ return movementVector;
+ }
+
+ /**
+ * Returns the current movement speed (magnitude of the movement vector).
+ *
+ * @return the scalar speed value
+ */
+ public double getMovementSpeed() {
+ return movementVector.getVectorLength();
+ }
+
+ /**
+ * Apply friction to camera movement vector.
+ *
+ * @param millisecondsPassedSinceLastFrame We want camera movement to be independent of framerate.
+ * Therefore, we take frame rendering time into account when translating
+ * camera between consecutive frames.
+ */
+ private void applyFrictionToMovement(int millisecondsPassedSinceLastFrame) {
+ for (int i = 0; i < millisecondsPassedSinceLastFrame; i++)
+ applyMillisecondFrictionToUserMovementVector();
+ }
+
+ /**
+ * Apply friction to camera movement vector.
+ */
+ private void applyMillisecondFrictionToUserMovementVector() {
+ movementVector.x /= MILLISECOND_FRICTION;
+ movementVector.y /= MILLISECOND_FRICTION;
+ movementVector.z /= MILLISECOND_FRICTION;
+ }
+
+ /**
+ * Translate coordinates based on camera movement vector and camera orientation in the world.
+ *
+ * @param millisecondsPassedSinceLastFrame We want camera movement to be independent of framerate.
+ * Therefore, we take frame rendering time into account when translating
+ * camera between consecutive frames.
+ */
+ private void translateCameraLocationBasedOnMovementVector(int millisecondsPassedSinceLastFrame) {
+ final Matrix3x3 m = transform.getRotation().toMatrix();
+
+ final double forwardX = m.m20;
+ final double forwardY = m.m21;
+ final double forwardZ = m.m22;
+
+ final double rightX = m.m00;
+ final double rightY = m.m01;
+ final double rightZ = m.m02;
+
+ final Point3D location = transform.getTranslation();
+ final double ms = millisecondsPassedSinceLastFrame;
+
+ location.x += forwardX * movementVector.z * SPEED_MULTIPLIER * ms;
+ location.y += forwardY * movementVector.z * SPEED_MULTIPLIER * ms;
+ location.z += forwardZ * movementVector.z * SPEED_MULTIPLIER * ms;
+
+ location.x += rightX * movementVector.x * SPEED_MULTIPLIER * ms;
+ location.y += rightY * movementVector.x * SPEED_MULTIPLIER * ms;
+ location.z += rightZ * movementVector.x * SPEED_MULTIPLIER * ms;
+
+ location.y += movementVector.y * SPEED_MULTIPLIER * ms;
+ }
+
+ /**
+ * Returns the transform containing this camera's location and orientation.
+ *
+ * @return the transform (mutable reference)
+ */
+ public Transform getTransform() {
+ return transform;
+ }
+
+ /**
+ * Orients the camera to look at a target point in world coordinates.
+ *
+ * <p>Calculates the required XZ and YZ rotation angles to point the camera
+ * from its current position toward the target. Useful for programmatic
+ * camera control, cinematic sequences, and following objects.</p>
+ *
+ * <p><b>Example:</b></p>
+ * <pre>{@code
+ * Camera camera = viewPanel.getCamera();
+ * camera.getTransform().setTranslation(new Point3D(100, -50, -200));
+ * camera.lookAt(new Point3D(0, 0, 0)); // Point camera at origin
+ * }</pre>
+ *
+ * @param target the world-space point to look at
+ */
+ public void lookAt(final Point3D target) {
+ final Point3D pos = transform.getTranslation();
+ final double dx = target.x - pos.x;
+ final double dy = target.y - pos.y;
+ final double dz = target.z - pos.z;
+
+ final double angleXZ = -Math.atan2(dx, dz);
+ final double horizontalDist = Math.sqrt(dx * dx + dz * dz);
+ final double angleYZ = -Math.atan2(dy, horizontalDist);
+
+ transform.getRotation().set(Quaternion.fromAngles(angleXZ, angleYZ));
+ }
+}
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.geometry;
+
+/**
+ * Point in 3D space with integer coordinates. Used for octree voxel positions.
+ */
+public class IntegerPoint
+{
+ /** X coordinate. */
+ public int x;
+ /** Y coordinate. */
+ public int y;
+ /** Z coordinate. */
+ public int z = 0;
+
+ /**
+ * Creates a point at the origin (0, 0, 0).
+ */
+ public IntegerPoint()
+ {
+ }
+
+ /**
+ * Creates a point with the specified coordinates.
+ *
+ * @param x the X coordinate
+ * @param y the Y coordinate
+ * @param z the Z coordinate
+ */
+ public IntegerPoint(final int x, final int y, final int z)
+ {
+ this.x = x;
+ this.y = y;
+ this.z = z;
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.geometry;
+
+import static java.lang.Math.sqrt;
+
+/**
+ * A mutable 2D point or vector with double-precision coordinates.
+ *
+ * <p>{@code Point2D} represents either a position in 2D space or a directional vector,
+ * with public {@code x} and {@code y} fields for direct access. It is commonly used
+ * for screen-space coordinates after 3D-to-2D projection.</p>
+ *
+ * <p>All mutation methods return {@code this} for fluent chaining:</p>
+ * <pre>{@code
+ * Point2D p = new Point2D(10, 20)
+ * .multiply(2.0)
+ * .add(new Point2D(5, 5))
+ * .negate();
+ * // p is now (-25, -45)
+ * }</pre>
+ *
+ * <p><b>Mutability convention:</b></p>
+ * <ul>
+ * <li><b>Imperative verbs</b> ({@code add}, {@code subtract}, {@code negate}, {@code multiply},
+ * {@code divide}) mutate this point and return {@code this}</li>
+ * <li><b>{@code with}-prefixed methods</b> ({@code withAdded}, {@code withSubtracted}, {@code withNegated},
+ * {@code withMultiplied}, {@code withDivided}) return a new point without modifying this one</li>
+ * </ul>
+ *
+ * <p><b>Warning:</b> This class is mutable with public fields. Clone before storing
+ * references that should not be shared:</p>
+ * <pre>{@code
+ * Point2D safeCopy = original.clone();
+ * }</pre>
+ *
+ * @see Point3D the 3D equivalent
+ */
+public class Point2D implements Cloneable {
+
+ /** X coordinate (horizontal axis). */
+ public double x;
+ /** Y coordinate (vertical axis, positive = down in screen space). */
+ public double y;
+
+ /**
+ * Creates a point at the origin (0, 0).
+ */
+ public Point2D() {
+ }
+
+ /**
+ * Creates a point with the specified coordinates.
+ *
+ * @param x the X coordinate
+ * @param y the Y coordinate
+ */
+ public Point2D(final double x, final double y) {
+ this.x = x;
+ this.y = y;
+ }
+
+ /**
+ * Creates a point by copying coordinates from another point.
+ *
+ * @param parent the point to copy from
+ */
+ public Point2D(final Point2D parent) {
+ x = parent.x;
+ y = parent.y;
+ }
+
+
+ /**
+ * Adds another point to this point in place.
+ * This point is modified, the other point is not.
+ *
+ * @param otherPoint the point to add
+ * @return this point (for chaining)
+ * @see #withAdded(Point2D) for the non-mutating version that returns a new point
+ */
+ public Point2D add(final Point2D otherPoint) {
+ x += otherPoint.x;
+ y += otherPoint.y;
+ return this;
+ }
+
+ /**
+ * Checks if both coordinates are zero.
+ *
+ * @return {@code true} if current point coordinates are equal to zero
+ */
+ public boolean isZero() {
+ return (x == 0) && (y == 0);
+ }
+
+ /**
+ * Creates a new point by copying this point's coordinates.
+ *
+ * @return a new point with the same coordinates
+ */
+ @Override
+ public Point2D clone() {
+ return new Point2D(this);
+ }
+
+ /**
+ * Copies coordinates from another point into this point.
+ *
+ * @param otherPoint the point to copy coordinates from
+ */
+ public void clone(final Point2D otherPoint) {
+ x = otherPoint.x;
+ y = otherPoint.y;
+ }
+
+ /**
+ * Sets this point to the midpoint between two other points.
+ *
+ * @param p1 the first point
+ * @param p2 the second point
+ * @return this point (for chaining)
+ */
+ public Point2D setToMiddle(final Point2D p1, final Point2D p2) {
+ x = (p1.x + p2.x) / 2d;
+ y = (p1.y + p2.y) / 2d;
+ return this;
+ }
+
+ /**
+ * Computes the angle on the X-Y plane between this point and another point.
+ *
+ * @param anotherPoint the other point
+ * @return the angle in radians
+ */
+ public double getAngleXY(final Point2D anotherPoint) {
+ return Math.atan2(x - anotherPoint.x, y - anotherPoint.y);
+ }
+
+ /**
+ * Computes the Euclidean distance from this point to another point.
+ *
+ * @param anotherPoint the point to compute distance to
+ * @return the distance between the two points
+ */
+ public double getDistanceTo(final Point2D anotherPoint) {
+ final double xDiff = x - anotherPoint.x;
+ final double yDiff = y - anotherPoint.y;
+
+ return sqrt(((xDiff * xDiff) + (yDiff * yDiff)));
+ }
+
+ /**
+ * Computes the length of this vector (magnitude).
+ *
+ * @return the vector length
+ */
+ public double getVectorLength() {
+ return sqrt(((x * x) + (y * y)));
+ }
+
+ /**
+ * Negates this point's coordinates in place.
+ * This point is modified.
+ *
+ * @return this point (for chaining)
+ * @see #withNegated() for the non-mutating version that returns a new point
+ */
+ public Point2D negate() {
+ x = -x;
+ y = -y;
+ return this;
+ }
+
+ /**
+ * Rounds this point's coordinates to integer values.
+ */
+ public void roundToInteger() {
+ x = (int) x;
+ y = (int) y;
+ }
+
+ /**
+ * Subtracts another point from this point in place.
+ * This point is modified, the other point is not.
+ *
+ * @param otherPoint the point to subtract
+ * @return this point (for chaining)
+ * @see #withSubtracted(Point2D) for the non-mutating version that returns a new point
+ */
+ public Point2D subtract(final Point2D otherPoint) {
+ x -= otherPoint.x;
+ y -= otherPoint.y;
+ return this;
+ }
+
+ /**
+ * Multiplies both coordinates by a factor.
+ * This point is modified.
+ *
+ * @param factor the multiplier
+ * @return this point (for chaining)
+ * @see #withMultiplied(double) for the non-mutating version that returns a new point
+ */
+ public Point2D multiply(final double factor) {
+ x *= factor;
+ y *= factor;
+ return this;
+ }
+
+ /**
+ * Divides both coordinates by a factor.
+ * This point is modified.
+ *
+ * @param factor the divisor
+ * @return this point (for chaining)
+ * @see #withDivided(double) for the non-mutating version that returns a new point
+ */
+ public Point2D divide(final double factor) {
+ x /= factor;
+ y /= factor;
+ return this;
+ }
+
+ /**
+ * Converts this 2D point to a 3D point with z = 0.
+ *
+ * @return a new 3D point with the same x, y and z = 0
+ */
+ public Point3D to3D() {
+ return new Point3D(x, y, 0);
+ }
+
+ /**
+ * Resets this point's coordinates to (0, 0).
+ *
+ * @return this point (for chaining)
+ */
+ public Point2D zero() {
+ x = 0;
+ y = 0;
+ return this;
+ }
+
+ @Override
+ public String toString() {
+ return "Point2D{" +
+ "x=" + x +
+ ", y=" + y +
+ '}';
+ }
+
+ /**
+ * Returns a new point that is the sum of this point and another.
+ * This point is not modified.
+ *
+ * @param other the point to add
+ * @return a new Point2D representing the sum
+ * @see #add(Point2D) for the mutating version
+ */
+ public Point2D withAdded(final Point2D other) {
+ return new Point2D(x + other.x, y + other.y);
+ }
+
+ /**
+ * Returns a new point that is this point minus another.
+ * This point is not modified.
+ *
+ * @param other the point to subtract
+ * @return a new Point2D representing the difference
+ * @see #subtract(Point2D) for the mutating version
+ */
+ public Point2D withSubtracted(final Point2D other) {
+ return new Point2D(x - other.x, y - other.y);
+ }
+
+ /**
+ * Returns a new point with negated coordinates.
+ * This point is not modified.
+ *
+ * @return a new Point2D with negated coordinates
+ * @see #negate() for the mutating version
+ */
+ public Point2D withNegated() {
+ return new Point2D(-x, -y);
+ }
+
+ /**
+ * Returns a new point with coordinates multiplied by a factor.
+ * This point is not modified.
+ *
+ * @param factor the multiplier
+ * @return a new Point2D with multiplied coordinates
+ * @see #multiply(double) for the mutating version
+ */
+ public Point2D withMultiplied(final double factor) {
+ return new Point2D(x * factor, y * factor);
+ }
+
+ /**
+ * Returns a new point with coordinates divided by a factor.
+ * This point is not modified.
+ *
+ * @param factor the divisor
+ * @return a new Point2D with divided coordinates
+ * @see #divide(double) for the mutating version
+ */
+ public Point2D withDivided(final double factor) {
+ return new Point2D(x / factor, y / factor);
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.geometry;
+
+import eu.svjatoslav.aukio.e3d.geometry.IntegerPoint;
+
+import static java.lang.Math.*;
+
+/**
+ * A mutable 3D point or vector with double-precision coordinates.
+ *
+ * <p>{@code Point3D} is the fundamental coordinate type used throughout the Aukio 3D engine.
+ * It represents either a position in 3D space or a directional vector, with public
+ * {@code x}, {@code y}, {@code z} fields for direct access.</p>
+ *
+ * <p>All mutation methods return {@code this} for fluent chaining:</p>
+ * <pre>{@code
+ * Point3D p = new Point3D(10, 20, 30)
+ * .multiply(2.0)
+ * .translateX(5)
+ * .add(new Point3D(1, 1, 1));
+ * // p is now (25, 41, 61)
+ * }</pre>
+ *
+ * <p><b>Common operations:</b></p>
+ * <pre>{@code
+ * // Create points
+ * Point3D origin = Point3D.origin(); // (0, 0, 0)
+ * Point3D pos = Point3D.point(100, 200, 300);
+ * Point3D copy = new Point3D(pos); // clone
+ *
+ * // Measure distance
+ * double dist = pos.getDistanceTo(origin);
+ *
+ * // Rotation
+ * pos.rotate(origin, Math.PI / 4, 0); // rotate 45 degrees on XZ plane
+ *
+ * // Scale
+ * pos.multiply(2.0); // double all coordinates
+ * pos.divide(2.0); // halve all coordinates
+ * }</pre>
+ *
+ * <p><b>Mutability convention:</b></p>
+ * <ul>
+ * <li><b>Imperative verbs</b> ({@code add}, {@code subtract}, {@code negate}, {@code multiply},
+ * {@code divide}) mutate this point and return {@code this}</li>
+ * <li><b>{@code with}-prefixed methods</b> ({@code withAdded}, {@code withSubtracted}, {@code withNegated},
+ * {@code withMultiplied}, {@code withDivided}) return a new point without modifying this one</li>
+ * </ul>
+ *
+ * <p><b>Warning:</b> This class is mutable with public fields. Clone before storing
+ * references that should not be shared:</p>
+ * <pre>{@code
+ * Point3D safeCopy = original.clone();
+ * }</pre>
+ *
+ * @see Point2D the 2D equivalent
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.Vertex wraps a Point3D with transform support
+ */
+public class Point3D implements Cloneable {
+
+ /** X coordinate (horizontal axis). */
+ public double x;
+ /** Y coordinate (vertical axis, positive = down in screen space). */
+ public double y;
+ /** Z coordinate (depth axis, positive = into the screen / away from viewer). */
+ public double z;
+
+ /**
+ * Creates a point at the origin (0, 0, 0).
+ */
+ public Point3D() {
+ }
+
+ /**
+ * Creates a point with the specified double-precision coordinates.
+ *
+ * @param x the X coordinate
+ * @param y the Y coordinate
+ * @param z the Z coordinate
+ */
+ public Point3D(final double x, final double y, final double z) {
+ this.x = x;
+ this.y = y;
+ this.z = z;
+ }
+
+ /**
+ * Creates a point with the specified float coordinates (widened to double).
+ *
+ * @param x the X coordinate
+ * @param y the Y coordinate
+ * @param z the Z coordinate
+ */
+ public Point3D(final float x, final float y, final float z) {
+ this.x = x;
+ this.y = y;
+ this.z = z;
+ }
+
+ /**
+ * Creates a point with the specified integer coordinates (widened to double).
+ *
+ * @param x the X coordinate
+ * @param y the Y coordinate
+ * @param z the Z coordinate
+ */
+ public Point3D(final int x, final int y, final int z) {
+ this.x = x;
+ this.y = y;
+ this.z = z;
+ }
+
+ /**
+ * Creates a point from an {@link IntegerPoint} (used by octree voxel coordinates).
+ *
+ * @param point the integer point to convert
+ */
+ public Point3D(IntegerPoint point) {
+ this.x = point.x;
+ this.y = point.y;
+ this.z = point.z;
+ }
+
+
+ /**
+ * Creates a new point by cloning coordinates from the parent point.
+ *
+ * @param parent the point to copy coordinates from
+ */
+ public Point3D(final Point3D parent) {
+ x = parent.x;
+ y = parent.y;
+ z = parent.z;
+ }
+
+ /**
+ * Returns a new point at the origin (0, 0, 0).
+ *
+ * @return a new Point3D at the origin
+ */
+ public static Point3D origin() {
+ return new Point3D();
+ }
+
+ /**
+ * Returns a new point with the specified coordinates.
+ *
+ * @param x the X coordinate
+ * @param y the Y coordinate
+ * @param z the Z coordinate
+ * @return a new Point3D with the given coordinates
+ */
+ public static Point3D point(final double x, final double y, final double z) {
+ return new Point3D(x, y, z);
+ }
+
+ /**
+ * Adds another point to this point in place.
+ * This point is modified, the other point is not.
+ *
+ * @param otherPoint the point to add
+ * @return this point (for chaining)
+ * @see #withAdded(Point3D) for the non-mutating version that returns a new point
+ */
+ public Point3D add(final Point3D otherPoint) {
+ x += otherPoint.x;
+ y += otherPoint.y;
+ z += otherPoint.z;
+ return this;
+ }
+
+ /**
+ * Adds coordinates of current point to one or more other points.
+ * The current point's coordinates are added to each target point.
+ *
+ * @param otherPoints the points to add this point's coordinates to
+ * @return this point (for chaining)
+ */
+ public Point3D addTo(final Point3D... otherPoints) {
+ for (final Point3D otherPoint : otherPoints) otherPoint.add(this);
+ return this;
+ }
+
+ /**
+ * Create new point by cloning position of current point.
+ *
+ * @return newly created clone.
+ */
+ public Point3D clone() {
+ return new Point3D(this);
+ }
+
+ /**
+ * Copies coordinates from another point into this point.
+ *
+ * @param otherPoint the point to copy coordinates from
+ * @return this point (for chaining)
+ */
+ public Point3D clone(final Point3D otherPoint) {
+ x = otherPoint.x;
+ y = otherPoint.y;
+ z = otherPoint.z;
+ return this;
+ }
+
+ /**
+ * Set current point coordinates to the middle point between two other points.
+ *
+ * @param p1 first point.
+ * @param p2 second point.
+ * @return current point.
+ */
+ public Point3D computeMiddlePoint(final Point3D p1, final Point3D p2) {
+ x = (p1.x + p2.x) / 2d;
+ y = (p1.y + p2.y) / 2d;
+ z = (p1.z + p2.z) / 2d;
+ return this;
+ }
+
+ /**
+ * Checks if all coordinates are zero.
+ *
+ * @return {@code true} if current point coordinates are equal to zero
+ */
+ public boolean isZero() {
+ return (x == 0) && (y == 0) && (z == 0);
+ }
+
+ /**
+ * Computes the angle on the X-Z plane between this point and another point.
+ *
+ * @param anotherPoint the other point
+ * @return the angle in radians
+ */
+ public double getAngleXZ(final Point3D anotherPoint) {
+ return Math.atan2(x - anotherPoint.x, z - anotherPoint.z);
+ }
+
+ /**
+ * Computes the angle on the Y-Z plane between this point and another point.
+ *
+ * @param anotherPoint the other point
+ * @return the angle in radians
+ */
+ public double getAngleYZ(final Point3D anotherPoint) {
+ return Math.atan2(y - anotherPoint.y, z - anotherPoint.z);
+ }
+
+ /**
+ * Computes the angle on the X-Y plane between this point and another point.
+ *
+ * @param anotherPoint the other point
+ * @return the angle in radians
+ */
+ public double getAngleXY(final Point3D anotherPoint) {
+ return Math.atan2(x - anotherPoint.x, y - anotherPoint.y);
+ }
+
+ /**
+ * Compute distance to another point.
+ *
+ * @param anotherPoint point to compute distance to.
+ * @return distance to another point.
+ */
+ public double getDistanceTo(final Point3D anotherPoint) {
+ final double xDelta = x - anotherPoint.x;
+ final double yDelta = y - anotherPoint.y;
+ final double zDelta = z - anotherPoint.z;
+
+ return sqrt(((xDelta * xDelta) + (yDelta * yDelta) + (zDelta * zDelta)));
+ }
+
+ /**
+ * Computes the length (magnitude) of this vector.
+ *
+ * @return the vector length
+ */
+ public double getVectorLength() {
+ return sqrt(((x * x) + (y * y) + (z * z)));
+ }
+
+ /**
+ * Negates this point's coordinates in place.
+ * This point is modified.
+ *
+ * @return this point (for chaining)
+ * @see #withNegated() for the non-mutating version that returns a new point
+ */
+ public Point3D negate() {
+ x = -x;
+ y = -y;
+ z = -z;
+ return this;
+ }
+
+ /**
+ * Rotates this point around a center point by the given XZ and YZ angles.
+ * <p>
+ * See also: <a href="https://marctenbosch.com/quaternions/">Let's remove Quaternions from every 3D Engine</a>
+ *
+ * @param center the center point to rotate around
+ * @param angleXZ the angle in the XZ plane (yaw) in radians
+ * @param angleYZ the angle in the YZ plane (pitch) in radians
+ * @return this point (for chaining)
+ */
+ public Point3D rotate(final Point3D center, final double angleXZ,
+ final double angleYZ) {
+ final double s1 = sin(angleXZ);
+ final double c1 = cos(angleXZ);
+
+ final double s2 = sin(angleYZ);
+ final double c2 = cos(angleYZ);
+
+ x -= center.x;
+ y -= center.y;
+ z -= center.z;
+
+ final double y1 = (z * s2) + (y * c2);
+ final double z1 = (z * c2) - (y * s2);
+
+ final double x1 = (z1 * s1) + (x * c1);
+ final double z2 = (z1 * c1) - (x * s1);
+
+ x = x1 + center.x;
+ y = y1 + center.y;
+ z = z2 + center.z;
+
+ return this;
+ }
+
+ /**
+ * Rotate current point around the origin by the given angles.
+ *
+ * @param angleXZ angle around the XZ plane (yaw), in radians
+ * @param angleYZ angle around the YZ plane (pitch), in radians
+ * @return this point (mutated)
+ */
+ public Point3D rotate(final double angleXZ, final double angleYZ) {
+ return rotate(new Point3D(0, 0, 0), angleXZ, angleYZ);
+ }
+
+ /**
+ * Round current point coordinates to integer values.
+ */
+ public void roundToInteger() {
+ x = (int) x;
+ y = (int) y;
+ z = (int) z;
+ }
+
+ /**
+ * Divides all coordinates by a factor.
+ * This point is modified.
+ *
+ * @param factor the divisor
+ * @return this point (for chaining)
+ * @see #withDivided(double) for the non-mutating version that returns a new point
+ */
+ public Point3D divide(final double factor) {
+ x /= factor;
+ y /= factor;
+ z /= factor;
+ return this;
+ }
+
+ /**
+ * Multiplies all coordinates by a factor.
+ * This point is modified.
+ *
+ * @param factor the multiplier
+ * @return this point (for chaining)
+ * @see #withMultiplied(double) for the non-mutating version that returns a new point
+ */
+ public Point3D multiply(final double factor) {
+ x *= factor;
+ y *= factor;
+ z *= factor;
+ return this;
+ }
+
+ /**
+ * Set current point coordinates to given values.
+ *
+ * @param x X coordinate.
+ * @param y Y coordinate.
+ * @param z Z coordinate.
+ */
+ public void setValues(final double x, final double y, final double z) {
+ this.x = x;
+ this.y = y;
+ this.z = z;
+ }
+
+ /**
+ * Subtracts another point from this point in place.
+ * This point is modified, the other point is not.
+ *
+ * @param otherPoint the point to subtract
+ * @return this point (for chaining)
+ * @see #withSubtracted(Point3D) for the non-mutating version that returns a new point
+ */
+ public Point3D subtract(final Point3D otherPoint) {
+ x -= otherPoint.x;
+ y -= otherPoint.y;
+ z -= otherPoint.z;
+ return this;
+ }
+
+ @Override
+ public String toString() {
+ return "x:" + x + " y:" + y + " z:" + z;
+ }
+
+ /**
+ * Translates this point along the X axis.
+ *
+ * @param xIncrement the amount to add to the X coordinate
+ * @return this point (for chaining)
+ */
+ public Point3D translateX(final double xIncrement) {
+ x += xIncrement;
+ return this;
+ }
+
+ /**
+ * Translates this point along the Y axis.
+ *
+ * @param yIncrement the amount to add to the Y coordinate
+ * @return this point (for chaining)
+ */
+ public Point3D translateY(final double yIncrement) {
+ y += yIncrement;
+ return this;
+ }
+
+ /**
+ * Translates this point along the Z axis.
+ *
+ * @param zIncrement the amount to add to the Z coordinate
+ * @return this point (for chaining)
+ */
+ public Point3D translateZ(final double zIncrement) {
+ z += zIncrement;
+ return this;
+ }
+
+ /**
+ * Here we assume that Z coordinate is distance to the viewer.
+ * If Z is positive, then point is in front of the viewer, and therefore it is visible.
+ *
+ * @return point visibility status.
+ */
+ public boolean isVisible() {
+ return z > 0;
+ }
+
+ /**
+ * Resets point coordinates to zero along all axes.
+ *
+ * @return current point.
+ */
+ public Point3D zero() {
+ x = 0;
+ y = 0;
+ z = 0;
+ return this;
+ }
+
+ /**
+ * Computes the dot product of this vector with another.
+ *
+ * @param other the other vector
+ * @return the dot product (scalar)
+ */
+ public double dot(final Point3D other) {
+ return x * other.x + y * other.y + z * other.z;
+ }
+
+ /**
+ * Computes the cross-product of this vector with another.
+ * Returns a new vector perpendicular to both input vectors.
+ *
+ * @param other the other vector
+ * @return a new Point3D representing the cross-product
+ */
+ public Point3D cross(final Point3D other) {
+ return new Point3D(
+ y * other.z - z * other.y,
+ z * other.x - x * other.z,
+ x * other.y - y * other.x
+ );
+ }
+
+ /**
+ * Returns a new point that is the sum of this point and another.
+ * This point is not modified.
+ *
+ * @param other the point to add
+ * @return a new Point3D representing the sum
+ * @see #add(Point3D) for the mutating version
+ */
+ public Point3D withAdded(final Point3D other) {
+ return new Point3D(x + other.x, y + other.y, z + other.z);
+ }
+
+ /**
+ * Returns a new point that is this point minus another.
+ * This point is not modified.
+ *
+ * @param other the point to subtract
+ * @return a new Point3D representing the difference
+ * @see #subtract(Point3D) for the mutating version
+ */
+ public Point3D withSubtracted(final Point3D other) {
+ return new Point3D(x - other.x, y - other.y, z - other.z);
+ }
+
+ /**
+ * Returns a new point with negated coordinates.
+ * This point is not modified.
+ *
+ * @return a new Point3D with negated coordinates
+ * @see #negate() for the mutating version
+ */
+ public Point3D withNegated() {
+ return new Point3D(-x, -y, -z);
+ }
+
+ /**
+ * Returns a new unit vector (normalized) in the same direction.
+ * This point is not modified.
+ *
+ * @return a new Point3D with unit length
+ */
+ public Point3D unit() {
+ final double len = getVectorLength();
+ if (len == 0) {
+ return new Point3D(0, 0, 0);
+ }
+ return new Point3D(x / len, y / len, z / len);
+ }
+
+ /**
+ * Returns a new point that is a linear interpolation between this point and another.
+ * When t=0, returns this point. When t=1, returns the other point.
+ *
+ * @param other the other point
+ * @param t the interpolation parameter (0 to 1)
+ * @return a new Point3D representing the interpolated position
+ */
+ public Point3D interpolate(final Point3D other, final double t) {
+ return new Point3D(
+ x + (other.x - x) * t,
+ y + (other.y - y) * t,
+ z + (other.z - z) * t
+ );
+ }
+
+ /**
+ * Returns a new point with coordinates multiplied by a factor.
+ * This point is not modified.
+ *
+ * @param factor the multiplier
+ * @return a new Point3D with multiplied coordinates
+ * @see #multiply(double) for the mutating version
+ */
+ public Point3D withMultiplied(final double factor) {
+ return new Point3D(x * factor, y * factor, z * factor);
+ }
+
+ /**
+ * Returns a new point with coordinates divided by a factor.
+ * This point is not modified.
+ *
+ * @param factor the divisor
+ * @return a new Point3D with divided coordinates
+ * @see #divide(double) for the mutating version
+ */
+ public Point3D withDivided(final double factor) {
+ return new Point3D(x / factor, y / factor, z / factor);
+ }
+
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.geometry;
+
+/**
+ * Utility class for polygon operations, primarily point-in-polygon testing.
+ *
+ * <p>Provides static methods for geometric computations on triangles and other polygons.</p>
+ *
+ * @see Point2D
+ */
+public class Polygon {
+
+ /**
+ * Creates a new Polygon utility instance.
+ */
+ public Polygon() {
+ }
+
+
+ /**
+ * Checks if a point is on the right side of a directed line segment.
+ * Used internally for ray-casting in point-in-polygon tests.
+ *
+ * @param point the point to test
+ * @param lineP1 the start point of the line segment
+ * @param lineP2 the end point of the line segment
+ * @return {@code true} if the point is on the right side of the line
+ */
+ private static boolean intersectsLine(final Point2D point, Point2D lineP1,
+ Point2D lineP2) {
+
+ // Sort line points by y coordinate.
+ if (lineP1.y > lineP2.y) {
+ final Point2D tmp = lineP1;
+ lineP1 = lineP2;
+ lineP2 = tmp;
+ }
+
+ // Check if point is within line y range.
+ if (point.y < lineP1.y || point.y > lineP2.y)
+ return false;
+
+ // Check if point is on the line.
+ final double xp = lineP2.x - lineP1.x;
+ final double yp = lineP2.y - lineP1.y;
+
+ final double crossX = lineP1.x + ((xp * (point.y - lineP1.y)) / yp);
+
+ return point.x >= crossX;
+ }
+
+ /**
+ * Tests whether a point lies inside a triangle using the ray-casting algorithm.
+ *
+ * <p>Casts a horizontal ray from the test point and counts intersections
+ * with the triangle edges. If the number of intersections is odd, the point is inside.</p>
+ *
+ * @param point the point to test
+ * @param p1 the first vertex of the triangle
+ * @param p2 the second vertex of the triangle
+ * @param p3 the third vertex of the triangle
+ * @return {@code true} if the point is inside the triangle
+ */
+ public static boolean pointWithinPolygon(final Point2D point, Point2D p1, Point2D p2, Point2D p3) {
+
+ int intersectionCount = 0;
+
+ if (intersectsLine(point, p1, p2))
+ intersectionCount++;
+
+ if (intersectsLine(point, p2, p3))
+ intersectionCount++;
+
+ if (intersectsLine(point, p3, p1))
+ intersectionCount++;
+
+ return intersectionCount == 1;
+ }
+
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.geometry;
+
+import static java.lang.Math.abs;
+import static java.lang.Math.min;
+
+/**
+ * A 2D axis-aligned rectangle defined by two corner points.
+ *
+ * <p>The rectangle is defined by two points ({@link #p1} and {@link #p2}) that represent
+ * opposite corners. The rectangle does not enforce ordering of these points.</p>
+ *
+ * @see Point2D
+ * @see Box the 3D equivalent
+ */
+public class Rectangle {
+
+ /**
+ * The corner points of the rectangle (opposite corners).
+ */
+ public Point2D p1, p2;
+
+ /**
+ * Creates a square rectangle centered at the origin with the specified size.
+ *
+ * @param size the width and height of the square
+ */
+ public Rectangle(final double size) {
+ p2 = new Point2D(size / 2, size / 2);
+ p1 = p2.clone().negate();
+ }
+
+ /**
+ * Creates a rectangle with the specified corner points.
+ *
+ * @param p1 the first corner point
+ * @param p2 the second corner point (opposite corner)
+ */
+ public Rectangle(final Point2D p1, final Point2D p2) {
+ this.p1 = p1;
+ this.p2 = p2;
+ }
+
+ /**
+ * Returns the height of the rectangle (distance along the Y-axis).
+ *
+ * @return the height (always positive)
+ */
+ public double getHeight() {
+ return abs(p1.y - p2.y);
+ }
+
+ /**
+ * Returns the leftmost X coordinate of the rectangle.
+ *
+ * @return the minimum X value
+ */
+ public double getLowerX() {
+ return min(p1.x, p2.x);
+ }
+
+ /**
+ * Returns the topmost Y coordinate of the rectangle.
+ *
+ * @return the minimum Y value
+ */
+ public double getLowerY() {
+ return min(p1.y, p2.y);
+ }
+
+ /**
+ * Returns the width of the rectangle (distance along the X-axis).
+ *
+ * @return the width (always positive)
+ */
+ public double getWidth() {
+ return abs(p1.x - p2.x);
+ }
+
+}
--- /dev/null
+/**
+ * Provides basic geometry classes for 2D and 3D coordinates and shapes.
+ *
+ * @see eu.svjatoslav.aukio.e3d.geometry.Point2D
+ * @see eu.svjatoslav.aukio.e3d.geometry.Point3D
+ */
+package eu.svjatoslav.aukio.e3d.geometry;
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui;
+import eu.svjatoslav.aukio.e3d.geometry.Camera;
+
+import eu.svjatoslav.aukio.e3d.diag.EngineConfig;
+import eu.svjatoslav.aukio.e3d.diag.PersistentLog;
+import eu.svjatoslav.aukio.e3d.diag.Telemetry;
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+
+import javax.imageio.ImageIO;
+import java.awt.GraphicsDevice;
+import java.awt.GraphicsEnvironment;
+import java.awt.image.BufferedImage;
+import java.io.File;
+import java.io.IOException;
+import java.lang.management.ManagementFactory;
+import java.nio.file.Files;
+import java.nio.file.StandardCopyOption;
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+import java.util.Map;
+
+/**
+ * Writes a self-contained bug report directory the user can point a
+ * developer (or an AI assistant) at.
+ *
+ * <p>A new directory {@code bugreport-<timestamp>} is created under the
+ * configured {@code bugreport.dir} containing:</p>
+ * <ul>
+ * <li>{@code description.txt} — what the user wrote in the popup</li>
+ * <li>{@code info.txt} — camera pose, view/screen resolution, heap,
+ * telemetry snapshot, java/os versions, effective config</li>
+ * <li>{@code screenshot.png} — a copy of the last rendered frame</li>
+ * <li>{@code aukio.log} / {@code aukio.log.1} — the persistent logs,
+ * including output from a session that froze before the report
+ * could be made</li>
+ * <li>{@code histogram.txt} — live-object histogram from
+ * {@code jcmd <pid> GC.class_histogram} (the OOM smoking gun;
+ * skipped when jcmd is unavailable)</li>
+ * <li>{@code threads.txt} — full thread dump (hang diagnosis)</li>
+ * </ul>
+ */
+public final class BugReport {
+
+ private static final DateTimeFormatter DIR_FORMATTER =
+ DateTimeFormatter.ofPattern("yyyyMMdd-HHmmss");
+
+ private BugReport() {
+ }
+
+ /**
+ * Creates a bug report for the given view.
+ *
+ * @param viewPanel the view whose camera and last frame to capture
+ * (may be null — screenshot/camera are then
+ * skipped)
+ * @param description free-form user description of the problem
+ * @return the created report directory
+ */
+ public static File create(final ViewPanel viewPanel,
+ final String description) throws IOException {
+ final File root = EngineConfig.getBugReportDir();
+ File dir = new File(root,
+ "bugreport-" + LocalDateTime.now().format(DIR_FORMATTER));
+ int suffix = 1;
+ while (dir.exists()) {
+ dir = new File(dir.getPath() + "-" + (++suffix));
+ }
+ Files.createDirectories(dir.toPath());
+
+ Files.writeString(new File(dir, "description.txt").toPath(),
+ description == null ? "" : description);
+ writeInfo(new File(dir, "info.txt"), viewPanel);
+ writeScreenshot(dir, viewPanel);
+ copyLogs(dir);
+ writeHistogram(dir);
+ writeThreadDump(new File(dir, "threads.txt"));
+
+ System.out.println("[BUGREPORT] written to "
+ + dir.getAbsolutePath());
+ return dir;
+ }
+
+ private static void writeInfo(final File file,
+ final ViewPanel viewPanel)
+ throws IOException {
+ final Runtime rt = Runtime.getRuntime();
+ final long used = rt.totalMemory() - rt.freeMemory();
+ final StringBuilder sb = new StringBuilder();
+ sb.append("time = ").append(LocalDateTime.now()).append('\n');
+
+ if (viewPanel != null) {
+ final Camera camera = viewPanel.getCamera();
+ final Point3D pos = camera.getTransform().getTranslation();
+ final double[] angles =
+ camera.getTransform().getRotation().toAngles();
+ sb.append(String.format(
+ "camera = (%.2f, %.2f, %.2f, %.2f, %.2f, %.2f)"
+ + " # x, y, z, yaw, pitch, roll%n",
+ pos.x, pos.y, pos.z,
+ angles[0], angles[1], angles[2]));
+ sb.append(String.format("view.size = %dx%d%n",
+ viewPanel.getWidth(), viewPanel.getHeight()));
+ sb.append("measured.fps = ").append(String.format("%.1f",
+ viewPanel.getMeasuredFPS())).append('\n');
+ }
+
+ try {
+ final GraphicsDevice device = GraphicsEnvironment
+ .getLocalGraphicsEnvironment()
+ .getDefaultScreenDevice();
+ sb.append(String.format("screen.resolution = %dx%d@%dHz%n",
+ device.getDisplayMode().getWidth(),
+ device.getDisplayMode().getHeight(),
+ device.getDisplayMode().getRefreshRate()));
+ } catch (final Throwable t) {
+ sb.append("screen.resolution = unavailable (")
+ .append(t.getMessage()).append(")\n");
+ }
+
+ sb.append(String.format("heap.used = %d MB%nheap.max = %d MB%n",
+ used / (1024 * 1024), rt.maxMemory() / (1024 * 1024)));
+ sb.append("telemetry = ").append(Telemetry.snapshotLine())
+ .append('\n');
+ sb.append("java.version = ")
+ .append(System.getProperty("java.version")).append('\n');
+ sb.append("os = ").append(System.getProperty("os.name"))
+ .append(' ').append(System.getProperty("os.version"))
+ .append('\n');
+ sb.append("config.ipd.cm = ").append(EngineConfig.getIpdCm())
+ .append('\n');
+ sb.append("config.bugreport.dir = ")
+ .append(EngineConfig.getBugReportDir()).append('\n');
+ sb.append("config.log.dir = ")
+ .append(EngineConfig.getLogDir()).append('\n');
+
+ Files.writeString(file.toPath(), sb.toString());
+ }
+
+ private static void writeScreenshot(final File dir,
+ final ViewPanel viewPanel)
+ throws IOException {
+ if (viewPanel == null)
+ return;
+ final BufferedImage lastFrame = viewPanel.getLastFrameImage();
+ if (lastFrame == null) {
+ Files.writeString(new File(dir, "screenshot-missing.txt")
+ .toPath(),
+ "no frame had been rendered yet\n");
+ return;
+ }
+ // the engine reuses frame buffers (triple buffering) — copy
+ final BufferedImage copy = new BufferedImage(lastFrame.getWidth(),
+ lastFrame.getHeight(), BufferedImage.TYPE_INT_RGB);
+ copy.getGraphics().drawImage(lastFrame, 0, 0, null);
+ ImageIO.write(copy, "png", new File(dir, "screenshot.png"));
+ }
+
+ private static void copyLogs(final File dir) throws IOException {
+ final File log = PersistentLog.getLogFile();
+ if (log == null || !log.isFile())
+ return;
+ Files.copy(log.toPath(),
+ new File(dir, log.getName()).toPath(),
+ StandardCopyOption.REPLACE_EXISTING);
+ final File backup = new File(log.getParentFile(),
+ log.getName() + ".1");
+ if (backup.isFile()) {
+ Files.copy(backup.toPath(),
+ new File(dir, backup.getName()).toPath(),
+ StandardCopyOption.REPLACE_EXISTING);
+ }
+ }
+
+ /**
+ * Live-object histogram: forces a full GC and lists instance counts
+ * per class — the direct answer to "what is leaking". Best effort:
+ * needs the JDK's jcmd on the PATH. Bounded by a timeout: jcmd
+ * self-attach can hang in some environments, and a bug report must
+ * still complete without it.
+ */
+ private static void writeHistogram(final File dir) {
+ final String pid = String.valueOf(ProcessHandle.current().pid());
+ final File out = new File(dir, "histogram.txt");
+ try {
+ final Process process = new ProcessBuilder("jcmd", pid,
+ "GC.class_histogram").redirectErrorStream(true)
+ .redirectOutput(out).start();
+ final boolean done = process.waitFor(30,
+ java.util.concurrent.TimeUnit.SECONDS);
+ if (done && process.exitValue() == 0) {
+ return;
+ }
+ if (!done) {
+ process.destroyForcibly();
+ }
+ out.delete();
+ Files.writeString(
+ new File(dir, "histogram-unavailable.txt").toPath(),
+ "jcmd GC.class_histogram did not finish within 30s\n");
+ } catch (final Throwable t) {
+ try {
+ Files.writeString(
+ new File(dir, "histogram-unavailable.txt").toPath(),
+ "jcmd GC.class_histogram failed: " + t + "\n");
+ } catch (final IOException ignored) {
+ }
+ }
+ }
+
+ private static void writeThreadDump(final File file)
+ throws IOException {
+ final StringBuilder sb = new StringBuilder();
+ for (final Map.Entry<Thread, StackTraceElement[]> entry
+ : Thread.getAllStackTraces().entrySet()) {
+ final Thread thread = entry.getKey();
+ sb.append('"').append(thread.getName()).append('"')
+ .append(thread.isDaemon() ? " daemon" : "")
+ .append(" state=").append(thread.getState())
+ .append('\n');
+ for (final StackTraceElement element : entry.getValue()) {
+ sb.append(" at ").append(element).append('\n');
+ }
+ sb.append('\n');
+ }
+ sb.append("vm = ").append(ManagementFactory.getRuntimeMXBean()
+ .getVmName()).append('\n');
+ Files.writeString(file.toPath(), sb.toString());
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui;
+
+/**
+ * Per-ViewPanel developer tools that control diagnostic features.
+ *
+ * <p>Each {@link ViewPanel} has its own DeveloperTools instance, allowing
+ * different views to have independent debug configurations.</p>
+ *
+ * <p>Settings can be toggled at runtime via the {@link DeveloperToolsPanel}
+ * (opened with F12 key).</p>
+ *
+ * @see ViewPanel#getDeveloperTools()
+ * @see DeveloperToolsPanel
+ */
+public class DeveloperTools {
+
+ /**
+ * If {@code true}, textured polygon borders are drawn in yellow.
+ * Useful for visualizing polygon slicing for perspective-correct rendering.
+ */
+ public volatile boolean showPolygonBorders = false;
+
+ /**
+ * If {@code true}, only render even-numbered horizontal segments (0, 2, 4, 6).
+ * Odd segments (1, 3, 5, 7) will remain black. Useful for detecting
+ * if threads render outside their allocated screen area (overdraw detection).
+ */
+ public volatile boolean renderAlternateSegments = false;
+
+ /**
+ * If {@code true}, draws red horizontal lines at segment boundaries.
+ * Useful for visualizing which thread renders which screen area.
+ * Each line marks the boundary between two adjacent rendering segments.
+ */
+ public volatile boolean showSegmentBoundaries = false;
+
+ /**
+ * Creates a new DeveloperTools instance with all debug features disabled.
+ */
+ public DeveloperTools() {
+ }
+}
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui;
+import eu.svjatoslav.aukio.e3d.diag.DebugLogBuffer;
+import eu.svjatoslav.aukio.e3d.diag.ThreadActivityRecorder;
+import eu.svjatoslav.aukio.e3d.geometry.Camera;
+import eu.svjatoslav.aukio.e3d.renderer.raster.CullingStatistics;
+import eu.svjatoslav.aukio.e3d.renderer.raster.RenderingContext;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+
+import javax.swing.*;
+import javax.swing.event.ChangeEvent;
+import javax.swing.event.ChangeListener;
+import java.awt.*;
+import java.awt.datatransfer.StringSelection;
+import java.awt.event.ActionEvent;
+import java.awt.event.ActionListener;
+import java.awt.event.WindowAdapter;
+import java.awt.event.WindowEvent;
+import java.util.List;
+
+/**
+ * Developer tools panel for toggling diagnostic features and viewing logs.
+ *
+ * <p>Opens as a popup window when F12 is pressed. Provides:</p>
+ * <ul>
+ * <li>Checkboxes to toggle debug settings</li>
+ * <li>Camera position display with copy button</li>
+ * <li>Composite shape frustum culling statistics</li>
+ * <li>A scrollable log viewer showing captured debug output</li>
+ * <li>A button to clear the log buffer</li>
+ * <li>Resizable window with native maximize support</li>
+ * </ul>
+ *
+ * @see DeveloperTools
+ * @see DebugLogBuffer
+ */
+public class DeveloperToolsPanel extends JFrame {
+
+ private static final int UPDATE_INTERVAL_MS = 200;
+
+ /**
+ * The view panel whose camera is being displayed.
+ */
+ private final ViewPanel viewPanel;
+ /**
+ * The developer tools being controlled.
+ */
+ private final DeveloperTools developerTools;
+ /**
+ * The log buffer being displayed.
+ */
+ private final DebugLogBuffer debugLogBuffer;
+ /**
+ * The text area showing log messages.
+ */
+ private final JTextArea logArea;
+ /**
+ * The label showing camera position.
+ */
+ private final JLabel cameraLabel;
+ /**
+ * The label showing total composites count.
+ */
+ private final JLabel totalCompositesLabel;
+ /**
+ * The label showing culled composites count.
+ */
+ private final JLabel culledCompositesLabel;
+ /**
+ * The label showing culled percentage.
+ */
+ private final JLabel culledPercentLabel;
+ /**
+ * The label showing current render thread count.
+ */
+ private final JLabel renderThreadsLabel;
+ /**
+ * The label showing the current target FPS.
+ */
+ private final JLabel targetFpsLabel;
+ /**
+ * The label showing the measured FPS.
+ */
+ private final JLabel measuredFpsLabel;
+ /**
+ * Toggle button switching between target FPS and unlimited FPS.
+ */
+ private final JToggleButton unlockFpsButton;
+ /**
+ * The per-thread activity timeline.
+ */
+ private final ThreadTimelineComponent threadTimeline;
+ /**
+ * Toggle button enabling thread activity recording.
+ */
+ private final JToggleButton recordTimelineButton;
+ /**
+ * Target FPS to restore when re-locking after an unlock.
+ */
+ private int lockedFPS = 60;
+ /**
+ * Timer for periodic updates.
+ */
+ private final Timer updateTimer;
+ /**
+ * Flag to prevent concurrent updates.
+ */
+ private volatile boolean updating = false;
+
+ /**
+ * Creates and displays a developer tools panel.
+ *
+ * @param parent the parent frame (for centering)
+ * @param viewPanel the view panel whose camera to display
+ * @param developerTools the developer tools to control
+ * @param debugLogBuffer the log buffer to display
+ */
+ public DeveloperToolsPanel(final Frame parent, final ViewPanel viewPanel,
+ final DeveloperTools developerTools,
+ final DebugLogBuffer debugLogBuffer) {
+ super("Developer Tools");
+ this.viewPanel = viewPanel;
+ this.developerTools = developerTools;
+ this.debugLogBuffer = debugLogBuffer;
+
+ setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
+ setLayout(new BorderLayout(8, 8));
+
+ cameraLabel = new JLabel(" ");
+ cameraLabel.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 12));
+
+ // Initialize culling statistics labels
+ totalCompositesLabel = new JLabel("0");
+ totalCompositesLabel.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 12));
+ culledCompositesLabel = new JLabel("0");
+ culledCompositesLabel.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 12));
+ culledPercentLabel = new JLabel("0.0%");
+ culledPercentLabel.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 12));
+
+ // Initialize render threads label
+ renderThreadsLabel = new JLabel(String.valueOf(viewPanel.getNumRenderThreads()));
+ renderThreadsLabel.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 12));
+
+ // Initialize frame rate display and unlock toggle
+ targetFpsLabel = new JLabel(" ");
+ targetFpsLabel.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 12));
+ measuredFpsLabel = new JLabel(" ");
+ measuredFpsLabel.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 12));
+ unlockFpsButton = new JToggleButton("Unlock FPS");
+ unlockFpsButton.setToolTipText(
+ "Disable the frame rate cap so the application renders as fast as it can (benchmark mode)");
+ unlockFpsButton.setSelected(viewPanel.getTargetFPS() <= 0);
+ unlockFpsButton.addActionListener(new ActionListener() {
+ @Override
+ public void actionPerformed(final ActionEvent e) {
+ if (unlockFpsButton.isSelected()) {
+ final int current = viewPanel.getTargetFPS();
+ if (current > 0) {
+ lockedFPS = current;
+ }
+ viewPanel.setFrameRate(0);
+ } else {
+ viewPanel.setFrameRate(lockedFPS);
+ }
+ updateFrameRateLabels();
+ }
+ });
+
+ // Thread activity timeline with record toggle
+ threadTimeline = new ThreadTimelineComponent();
+ recordTimelineButton = new JToggleButton("Record");
+ recordTimelineButton.setToolTipText(
+ "Record per-thread activity (transform/paint/binning per frame, idle = black) for the timeline below");
+ recordTimelineButton.addActionListener(new ActionListener() {
+ @Override
+ public void actionPerformed(final ActionEvent e) {
+ ThreadActivityRecorder.setEnabled(recordTimelineButton.isSelected());
+ }
+ });
+
+ final JPanel topPanel = new JPanel();
+ topPanel.setLayout(new BoxLayout(topPanel, BoxLayout.Y_AXIS));
+ topPanel.add(createSettingsPanel());
+ topPanel.add(createCameraPanel());
+ topPanel.add(createCullingPanel());
+ topPanel.add(createRenderThreadsPanel());
+ topPanel.add(createFrameRatePanel());
+ topPanel.add(createThreadTimelinePanel());
+ add(topPanel, BorderLayout.NORTH);
+
+ logArea = new JTextArea(15, 60);
+ logArea.setEditable(false);
+ logArea.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 12));
+ logArea.setBackground(Color.BLACK);
+ logArea.setForeground(Color.GREEN);
+ final JScrollPane scrollPane = new JScrollPane(logArea);
+ scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
+ add(scrollPane, BorderLayout.CENTER);
+
+ final JPanel buttonPanel = createButtonPanel();
+ add(buttonPanel, BorderLayout.SOUTH);
+
+ pack();
+ setLocationRelativeTo(parent);
+
+ updateTimer = new Timer(UPDATE_INTERVAL_MS, new ActionListener() {
+ @Override
+ public void actionPerformed(final ActionEvent e) {
+ updateDisplay();
+ }
+ });
+
+ addWindowListener(new WindowAdapter() {
+ @Override
+ public void windowOpened(final WindowEvent e) {
+ updateDisplay();
+ updateTimer.start();
+ }
+
+ @Override
+ public void windowClosed(final WindowEvent e) {
+ updateTimer.stop();
+ }
+ });
+ }
+
+ private JPanel createSettingsPanel() {
+ final JPanel panel = new JPanel(new GridLayout(0, 1, 0, 2));
+ panel.setBorder(BorderFactory.createEmptyBorder(8, 8, 0, 8));
+
+ final JCheckBox showBordersCheckbox = new JCheckBox("Show polygon borders");
+ showBordersCheckbox.setSelected(developerTools.showPolygonBorders);
+ showBordersCheckbox.addChangeListener(new ChangeListener() {
+ @Override
+ public void stateChanged(final ChangeEvent e) {
+ developerTools.showPolygonBorders = showBordersCheckbox.isSelected();
+ }
+ });
+
+ final JCheckBox alternateSegmentsCheckbox = new JCheckBox("Render alternate segments (overdraw debug)");
+ alternateSegmentsCheckbox.setSelected(developerTools.renderAlternateSegments);
+ alternateSegmentsCheckbox.addChangeListener(new ChangeListener() {
+ @Override
+ public void stateChanged(final ChangeEvent e) {
+ developerTools.renderAlternateSegments = alternateSegmentsCheckbox.isSelected();
+ }
+ });
+
+ final JCheckBox segmentBoundariesCheckbox = new JCheckBox("Show segment boundaries");
+ segmentBoundariesCheckbox.setSelected(developerTools.showSegmentBoundaries);
+ segmentBoundariesCheckbox.addChangeListener(new ChangeListener() {
+ @Override
+ public void stateChanged(final ChangeEvent e) {
+ developerTools.showSegmentBoundaries = segmentBoundariesCheckbox.isSelected();
+ }
+ });
+
+ panel.add(showBordersCheckbox);
+ panel.add(alternateSegmentsCheckbox);
+ panel.add(segmentBoundariesCheckbox);
+
+ return panel;
+ }
+
+ private JPanel createCameraPanel() {
+ final JPanel panel = new JPanel(new BorderLayout(4, 4));
+ panel.setBorder(BorderFactory.createCompoundBorder(
+ BorderFactory.createEmptyBorder(8, 8, 8, 8),
+ BorderFactory.createTitledBorder("Camera (x, y, z, yaw, pitch, roll)")
+ ));
+
+ panel.add(cameraLabel, BorderLayout.CENTER);
+
+ final JButton copyButton = new JButton("Copy");
+ copyButton.setToolTipText("Copy camera position to clipboard");
+ copyButton.addActionListener(new ActionListener() {
+ @Override
+ public void actionPerformed(final ActionEvent e) {
+ final String text = cameraLabel.getText();
+ if (text != null && !text.trim().isEmpty()) {
+ final StringSelection sel = new StringSelection(text);
+ Toolkit.getDefaultToolkit().getSystemClipboard().setContents(sel, null);
+ }
+ }
+ });
+
+ final JButton pasteButton = new JButton("Paste");
+ pasteButton.setToolTipText(
+ "Set camera position from clipboard (six comma-separated"
+ + " numbers: x, y, z, yaw, pitch, roll); does"
+ + " nothing if the clipboard holds anything else");
+ pasteButton.addActionListener(new ActionListener() {
+ @Override
+ public void actionPerformed(final ActionEvent e) {
+ pasteCameraPosition();
+ }
+ });
+
+ final JPanel buttons = new JPanel(new GridLayout(0, 1, 0, 4));
+ buttons.add(copyButton);
+ buttons.add(pasteButton);
+ panel.add(buttons, BorderLayout.EAST);
+
+ return panel;
+ }
+
+ /**
+ * Strict decimal number: rejects NaN/Infinity/hex-float spellings
+ * that {@link Double#parseDouble(String)} would otherwise accept.
+ */
+ private static final java.util.regex.Pattern NUMBER =
+ java.util.regex.Pattern.compile(
+ "[+-]?(\\d+\\.?\\d*|\\.\\d+)([eE][+-]?\\d+)?");
+
+ /**
+ * Reads the system clipboard and, if it holds exactly six
+ * comma-separated numbers (the format {@link #updateCameraLabel()}
+ * and the Copy button produce), teleports the camera to
+ * x, y, z, yaw, pitch, roll. Anything else in the clipboard is
+ * ignored silently.
+ */
+ private void pasteCameraPosition() {
+ if (viewPanel == null) {
+ return;
+ }
+ final String text;
+ try {
+ final java.awt.datatransfer.Clipboard clipboard =
+ Toolkit.getDefaultToolkit().getSystemClipboard();
+ if (!clipboard.isDataFlavorAvailable(
+ java.awt.datatransfer.DataFlavor.stringFlavor)) {
+ return;
+ }
+ text = (String) clipboard.getData(
+ java.awt.datatransfer.DataFlavor.stringFlavor);
+ } catch (final Exception ex) {
+ return;
+ }
+ if (text == null) {
+ return;
+ }
+ final String[] parts = text.trim().split(",", -1);
+ if (parts.length != 6) {
+ return;
+ }
+ final double[] values = new double[6];
+ for (int i = 0; i < 6; i++) {
+ final String token = parts[i].trim();
+ if (!NUMBER.matcher(token).matches()) {
+ return;
+ }
+ values[i] = Double.parseDouble(token);
+ }
+ viewPanel.getCamera().getTransform().set(values[0], values[1],
+ values[2], values[3], values[4], values[5]);
+ updateCameraLabel();
+ }
+
+ private JPanel createCullingPanel() {
+ final JPanel panel = new JPanel();
+ panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
+ panel.setBorder(BorderFactory.createCompoundBorder(
+ BorderFactory.createEmptyBorder(0, 8, 8, 8),
+ BorderFactory.createTitledBorder("Composite shape frustum culling")
+ ));
+
+ // Single row: total, culled, percent
+ final JPanel statsRow = new JPanel(new FlowLayout(FlowLayout.LEFT, 4, 2));
+ statsRow.add(new JLabel("Total:"));
+ statsRow.add(totalCompositesLabel);
+ statsRow.add(new JLabel(" Culled:"));
+ statsRow.add(culledCompositesLabel);
+ statsRow.add(culledPercentLabel);
+
+ panel.add(statsRow);
+
+ return panel;
+ }
+
+ private JPanel createRenderThreadsPanel() {
+ final JPanel panel = new JPanel();
+ panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
+ panel.setBorder(BorderFactory.createCompoundBorder(
+ BorderFactory.createEmptyBorder(0, 8, 8, 8),
+ BorderFactory.createTitledBorder("Render Threads")
+ ));
+
+ final JPanel statsRow = new JPanel(new FlowLayout(FlowLayout.LEFT, 4, 2));
+ statsRow.add(new JLabel("Active:"));
+ statsRow.add(renderThreadsLabel);
+ statsRow.add(new JLabel(" Available cores:"));
+ statsRow.add(new JLabel(String.valueOf(Runtime.getRuntime().availableProcessors())));
+
+ panel.add(statsRow);
+
+ return panel;
+ }
+
+ private JPanel createFrameRatePanel() {
+ final JPanel panel = new JPanel();
+ panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
+ panel.setBorder(BorderFactory.createCompoundBorder(
+ BorderFactory.createEmptyBorder(0, 8, 8, 8),
+ BorderFactory.createTitledBorder("Frame Rate")
+ ));
+
+ final JPanel statsRow = new JPanel(new FlowLayout(FlowLayout.LEFT, 4, 2));
+ statsRow.add(new JLabel("Target:"));
+ statsRow.add(targetFpsLabel);
+ statsRow.add(new JLabel(" Measured:"));
+ statsRow.add(measuredFpsLabel);
+ statsRow.add(unlockFpsButton);
+
+ panel.add(statsRow);
+
+ return panel;
+ }
+
+ private JPanel createThreadTimelinePanel() {
+ final JPanel panel = new JPanel(new BorderLayout(4, 4));
+ panel.setBorder(BorderFactory.createCompoundBorder(
+ BorderFactory.createEmptyBorder(0, 8, 8, 8),
+ BorderFactory.createTitledBorder("Thread Timeline (idle = black; wheel = scroll, ctrl+wheel = zoom)")
+ ));
+ panel.add(recordTimelineButton, BorderLayout.NORTH);
+ panel.add(threadTimeline, BorderLayout.CENTER);
+ panel.add(threadTimeline.scrollBar, BorderLayout.SOUTH);
+ return panel;
+ }
+
+ private JPanel createButtonPanel() {
+ final JPanel panel = new JPanel(new FlowLayout(FlowLayout.LEFT));
+
+ final JButton clearButton = new JButton("Clear Logs");
+ clearButton.addActionListener(new ActionListener() {
+ @Override
+ public void actionPerformed(final ActionEvent e) {
+ debugLogBuffer.clear();
+ logArea.setText("");
+ }
+ });
+
+ final JButton bugReportButton = new JButton("Make Bug Report...");
+ bugReportButton.setToolTipText(
+ "Write a bug report directory: your description, a"
+ + " screenshot, camera position, logs and memory"
+ + " statistics");
+ bugReportButton.addActionListener(new ActionListener() {
+ @Override
+ public void actionPerformed(final ActionEvent e) {
+ showBugReportDialog();
+ }
+ });
+
+ panel.add(clearButton);
+ panel.add(bugReportButton);
+
+ return panel;
+ }
+
+ /**
+ * Popup asking what happened, then writes a bug report directory
+ * (screenshot + description + logs + memory stats) and shows the
+ * resulting path.
+ */
+ private void showBugReportDialog() {
+ final JTextArea descriptionArea = new JTextArea(8, 50);
+ descriptionArea.setLineWrap(true);
+ descriptionArea.setWrapStyleWord(true);
+ final JScrollPane scroll = new JScrollPane(descriptionArea);
+ scroll.setBorder(BorderFactory.createTitledBorder(
+ "What happened / what looks wrong?"));
+
+ final int choice = JOptionPane.showConfirmDialog(this, scroll,
+ "Make Bug Report", JOptionPane.OK_CANCEL_OPTION,
+ JOptionPane.PLAIN_MESSAGE);
+ if (choice != JOptionPane.OK_OPTION)
+ return;
+
+ try {
+ final java.io.File dir = BugReport.create(viewPanel,
+ descriptionArea.getText());
+ showBugReportResultDialog(dir);
+ } catch (final Exception ex) {
+ JOptionPane.showMessageDialog(this,
+ "Bug report failed: " + ex.getMessage(),
+ "Bug Report", JOptionPane.ERROR_MESSAGE);
+ }
+ }
+
+ /**
+ * Shows the created bug report's location in a selectable text
+ * field (copy-paste with Ctrl+C works) plus explicit Copy Path and
+ * Open Folder buttons — a plain JOptionPane message is neither
+ * selectable nor actionable.
+ */
+ private void showBugReportResultDialog(final java.io.File dir) {
+ final JDialog dialog = new JDialog(this, "Bug Report", true);
+ dialog.setLayout(new BorderLayout(8, 8));
+
+ final JPanel centerPanel = new JPanel(new BorderLayout(4, 4));
+ centerPanel.setBorder(BorderFactory.createEmptyBorder(8, 8, 0, 8));
+ centerPanel.add(new JLabel(
+ "Bug report written to (point the developer at this"
+ + " directory):"), BorderLayout.NORTH);
+ final JTextField pathField = new JTextField(
+ dir.getAbsolutePath());
+ pathField.setEditable(false);
+ pathField.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 12));
+ centerPanel.add(pathField, BorderLayout.CENTER);
+ dialog.add(centerPanel, BorderLayout.CENTER);
+
+ final JPanel buttonPanel = new JPanel(
+ new FlowLayout(FlowLayout.LEFT));
+
+ final JButton copyButton = new JButton("Copy Path");
+ copyButton.setToolTipText("Copy the report path to the clipboard");
+ copyButton.addActionListener(new ActionListener() {
+ @Override
+ public void actionPerformed(final ActionEvent e) {
+ final StringSelection sel = new StringSelection(
+ dir.getAbsolutePath());
+ Toolkit.getDefaultToolkit().getSystemClipboard()
+ .setContents(sel, null);
+ }
+ });
+ buttonPanel.add(copyButton);
+
+ final boolean openSupported = Desktop.isDesktopSupported()
+ && Desktop.getDesktop()
+ .isSupported(Desktop.Action.OPEN);
+ final JButton openButton = new JButton("Open Folder");
+ openButton.setToolTipText(openSupported
+ ? "Open the report directory in the file manager"
+ : "Opening folders is not supported on this desktop");
+ openButton.setEnabled(openSupported);
+ if (openSupported) {
+ openButton.addActionListener(new ActionListener() {
+ @Override
+ public void actionPerformed(final ActionEvent e) {
+ try {
+ Desktop.getDesktop().open(dir);
+ } catch (final Exception ex) {
+ JOptionPane.showMessageDialog(dialog,
+ "Could not open folder: "
+ + ex.getMessage(),
+ "Bug Report", JOptionPane.ERROR_MESSAGE);
+ }
+ }
+ });
+ }
+ buttonPanel.add(openButton);
+
+ final JButton closeButton = new JButton("Close");
+ closeButton.addActionListener(new ActionListener() {
+ @Override
+ public void actionPerformed(final ActionEvent e) {
+ dialog.dispose();
+ }
+ });
+ buttonPanel.add(closeButton);
+
+ dialog.add(buttonPanel, BorderLayout.SOUTH);
+ dialog.pack();
+ dialog.setLocationRelativeTo(this);
+ dialog.setVisible(true);
+ }
+
+ private void updateDisplay() {
+ if (updating) {
+ return;
+ }
+ updating = true;
+ try {
+ updateCameraLabel();
+ updateCullingStatistics();
+ updateRenderThreadsLabel();
+ updateFrameRateLabels();
+ updateLogDisplay();
+ threadTimeline.repaint();
+ } finally {
+ updating = false;
+ }
+ }
+
+ private void updateCameraLabel() {
+ if (viewPanel == null) {
+ return;
+ }
+
+ final Camera camera = viewPanel.getCamera();
+ final Point3D pos = camera.getTransform().getTranslation();
+ final double[] angles = camera.getTransform().getRotation().toAngles();
+
+ cameraLabel.setText(String.format("%.2f, %.2f, %.2f, %.2f, %.2f, %.2f",
+ pos.x, pos.y, pos.z, angles[0], angles[1], angles[2]));
+ }
+
+ private void updateCullingStatistics() {
+ if (viewPanel == null) {
+ return;
+ }
+
+ // Get the current rendering context from view panel's last render
+ final RenderingContext context = viewPanel.getRenderingContext();
+ if (context == null || context.cullingStatistics == null) {
+ totalCompositesLabel.setText("-");
+ culledCompositesLabel.setText("-");
+ culledPercentLabel.setText("-");
+ return;
+ }
+
+ final CullingStatistics stats = context.cullingStatistics;
+ totalCompositesLabel.setText(String.valueOf(stats.totalComposites.get()));
+ culledCompositesLabel.setText(String.valueOf(stats.culledComposites.get()));
+ culledPercentLabel.setText(String.format(" (%.1f%%)", stats.getCulledPercentage()));
+ }
+
+ private void updateRenderThreadsLabel() {
+ if (viewPanel == null) {
+ return;
+ }
+ renderThreadsLabel.setText(String.valueOf(viewPanel.getNumRenderThreads()));
+ }
+
+ private void updateFrameRateLabels() {
+ if (viewPanel == null) {
+ return;
+ }
+ final int target = viewPanel.getTargetFPS();
+ targetFpsLabel.setText(target > 0 ? String.valueOf(target) : "unlimited");
+ measuredFpsLabel.setText(String.format("%.1f", viewPanel.getMeasuredFPS()));
+ }
+
+ private void updateLogDisplay() {
+ final List<String> entries = debugLogBuffer.getEntries();
+ final StringBuilder sb = new StringBuilder();
+ for (final String entry : entries) {
+ sb.append(entry).append('\n');
+ }
+ logArea.setText(sb.toString());
+
+ final JScrollBar vertical = ((JScrollPane) logArea.getParent().getParent())
+ .getVerticalScrollBar();
+ vertical.setValue(vertical.getMaximum());
+ }
+}
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui;
+
+import eu.svjatoslav.aukio.e3d.gui.headtrack.HeadTracker;
+import eu.svjatoslav.aukio.e3d.gui.headtrack.HeadTrackingManager;
+import eu.svjatoslav.aukio.e3d.gui.spacemouse.SpaceMouseManager;
+import eu.svjatoslav.aukio.e3d.gui.spacemouse.SpaceNavigatorHid;
+
+/**
+ * Optional input-device hot-plug for a {@link ViewPanel}: starts the
+ * RayNeo head-tracking manager and the SpaceNavigator 6DOF-mouse manager
+ * (each auto-detects its device even when plugged in after startup), and
+ * exposes the currently connected device, if any.
+ *
+ * <p>Extracted from ViewPanel to keep the panel focused on the render
+ * pipeline. Either device can be disabled with
+ * {@code -De3d.headtrack=false} / {@code -De3d.spacemouse=false}.</p>
+ */
+final class DeviceHotplug {
+
+ /** Head tracker hot-plug manager, unless disabled via e3d.headtrack=false. */
+ private HeadTrackingManager headTrackingManager;
+
+ /** SpaceNavigator hot-plug manager, unless disabled via e3d.spacemouse=false. */
+ private SpaceMouseManager spaceMouseManager;
+
+ /**
+ * Starts both hot-plug managers for the given panel (respecting the
+ * disable properties).
+ *
+ * @param viewPanel the panel whose camera the devices will drive
+ */
+ DeviceHotplug(final ViewPanel viewPanel) {
+ if (!"false".equalsIgnoreCase(
+ System.getProperty("e3d.headtrack", "true"))) {
+ headTrackingManager = new HeadTrackingManager(viewPanel);
+ headTrackingManager.start();
+ }
+ if (!"false".equalsIgnoreCase(
+ System.getProperty("e3d.spacemouse", "true"))) {
+ spaceMouseManager = new SpaceMouseManager(viewPanel);
+ spaceMouseManager.start();
+ }
+ }
+
+ /**
+ * Returns the active SpaceNavigator device, or null when no 6DOF
+ * mouse is currently connected.
+ */
+ SpaceNavigatorHid getSpaceMouse() {
+ return spaceMouseManager == null ? null
+ : spaceMouseManager.getDevice();
+ }
+
+ /**
+ * Returns the active head tracker, or null when no glasses are
+ * currently connected.
+ */
+ HeadTracker getHeadTracker() {
+ return headTrackingManager == null ? null
+ : headTrackingManager.getTracker();
+ }
+
+ /** Stops both hot-plug managers; safe to call more than once. */
+ void stop() {
+ if (headTrackingManager != null) {
+ headTrackingManager.stop();
+ headTrackingManager = null;
+ }
+ if (spaceMouseManager != null) {
+ spaceMouseManager.stop();
+ spaceMouseManager = null;
+ }
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui;
+
+/**
+ * Listener interface for per-frame callbacks before the 3D scene is rendered.
+ *
+ * <p>Implement this interface and register it with
+ * {@link ViewPanel#addFrameListener(FrameListener)} to receive a callback
+ * before each frame. This is the primary mechanism for implementing animations,
+ * physics updates, and other time-dependent behavior.</p>
+ *
+ * <p><b>Usage example - animating a shape:</b></p>
+ * <pre>{@code
+ * viewPanel.addFrameListener((panel, deltaMs) -> {
+ * // Rotate the shape a little each frame
+ * double angleIncrement = deltaMs * 0.001; // radians per millisecond
+ * myShape.setTransform(new Transform(
+ * myShape.getLocation(),
+ * currentAngle += angleIncrement, 0
+ * ));
+ * return true; // request repaint since we changed something
+ * });
+ * }</pre>
+ *
+ * <p>The engine uses the return values to optimize rendering: if no listener
+ * returns {@code true} and no other changes occurred, the frame is skipped
+ * to save CPU and energy.</p>
+ *
+ * @see ViewPanel#addFrameListener(FrameListener)
+ * @see ViewPanel#removeFrameListener(FrameListener)
+ */
+public interface FrameListener {
+
+ /**
+ * Called before each frame render, allowing the listener to update state
+ * and indicate whether a repaint is needed.
+ *
+ * <p>Each registered listener is called exactly once per frame tick.
+ * The frame is only rendered if at least one listener returns {@code true}
+ * (or if the view was explicitly marked for repaint).</p>
+ *
+ * @param viewPanel the view panel being rendered
+ * @param millisecondsSinceLastFrame time elapsed since the previous frame,
+ * for frame-rate-independent updates
+ * @return {@code true} if the view should be re-rendered this frame,
+ * {@code false} if this listener has no visual changes
+ */
+ boolean onFrame(ViewPanel viewPanel, int millisecondsSinceLastFrame);
+}
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui;
+
+import eu.svjatoslav.aukio.e3d.geometry.Box;
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.gui.humaninput.KeyboardFocusStack;
+import eu.svjatoslav.aukio.e3d.gui.humaninput.KeyboardHelper;
+import eu.svjatoslav.aukio.e3d.gui.humaninput.KeyboardInputHandler;
+import eu.svjatoslav.aukio.e3d.gui.humaninput.MouseEvent;
+import eu.svjatoslav.aukio.e3d.gui.humaninput.MouseInteractionController;
+import eu.svjatoslav.aukio.e3d.math.Transform;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.line.LineAppearance;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.wireframe.WireframeBox;
+
+import java.awt.event.KeyEvent;
+
+/**
+ * Base class for interactive GUI components rendered in 3D space.
+ *
+ * <p>{@code GuiComponent} combines a composite shape with keyboard and mouse interaction
+ * handling. When clicked, it acquires keyboard focus (via the {@link eu.svjatoslav.aukio.e3d.gui.humaninput.KeyboardFocusStack}),
+ * and a red wireframe border is displayed to indicate focus. Pressing ESC releases focus.</p>
+ *
+ * <p>This class is the foundation for interactive widgets like the
+ * {@link eu.svjatoslav.aukio.e3d.gui.textEditorComponent.TextEditComponent}.</p>
+ *
+ * <p><b>Usage example - creating a custom GUI component:</b></p>
+ * <pre>{@code
+ * GuiComponent myWidget = new GuiComponent(
+ * new Transform(new Point3D(0, 0, 300)),
+ * viewPanel,
+ * new Point3D(400, 300, 0) // width, height, depth
+ * );
+ *
+ * // Add visual content to the widget
+ * myWidget.addShape(someTextCanvas);
+ *
+ * // Add to the scene
+ * viewPanel.getRootShapeCollection().addShape(myWidget);
+ * }</pre>
+ *
+ * @see eu.svjatoslav.aukio.e3d.gui.humaninput.KeyboardFocusStack manages which component has keyboard focus
+ * @see eu.svjatoslav.aukio.e3d.gui.textEditorComponent.TextEditComponent a full text editor built on this class
+ */
+public class GuiComponent extends AbstractCompositeShape implements
+ KeyboardInputHandler, MouseInteractionController {
+
+ private static final String GROUP_GUI_FOCUS = "gui.focus";
+
+ /**
+ * The view panel this component is attached to.
+ */
+ public final ViewPanel viewPanel;
+ Box containingBox = new Box();
+ private WireframeBox borders = null;
+
+ private boolean borderShown = false;
+
+ /**
+ * Creates a GUI component with the specified transform, view panel, and bounding box size.
+ *
+ * @param transform the position and orientation of the component in 3D space
+ * @param viewPanel the view panel this component belongs to
+ * @param size the bounding box dimensions (width, height, depth)
+ */
+ public GuiComponent(final Transform transform,
+ final ViewPanel viewPanel, final Point3D size) {
+ super(transform);
+ this.viewPanel = viewPanel;
+ setDimensions(size);
+ }
+
+ private WireframeBox createBorder() {
+ final LineAppearance appearance = new LineAppearance(10,
+ new eu.svjatoslav.aukio.e3d.renderer.raster.Color(255, 0, 0, 100));
+
+ final double borderSize = 10;
+
+ final Box borderArea = containingBox.clone().enlarge(borderSize);
+
+ return new WireframeBox(borderArea, appearance);
+ }
+
+ @Override
+ public boolean focusLost(final ViewPanel viewPanel) {
+ hideBorder();
+ return true;
+ }
+
+ @Override
+ public boolean focusReceived(final ViewPanel viewPanel) {
+ showBorder();
+ return true;
+ }
+
+ /**
+ * Returns whether this component currently holds keyboard focus.
+ *
+ * @return {@code true} when focused (focus border is shown)
+ */
+ public boolean hasKeyboardFocus() {
+ return borderShown;
+ }
+
+ /**
+ * Returns the wireframe border box for this component.
+ *
+ * @return the border wireframe box
+ */
+ public WireframeBox getBorders() {
+ if (borders == null)
+ borders = createBorder();
+ return borders;
+ }
+
+ /**
+ * Returns the depth of this component's bounding box.
+ *
+ * @return the depth in pixels
+ */
+ public int getDepth() {
+ return (int) containingBox.getDepth();
+ }
+
+ /**
+ * Returns the height of this component's bounding box.
+ *
+ * @return the height in pixels
+ */
+ public int getHeight() {
+ return (int) containingBox.getHeight();
+ }
+
+ /**
+ * Returns the width of this component's bounding box.
+ *
+ * @return the width in pixels
+ */
+ public int getWidth() {
+ return (int) containingBox.getWidth();
+ }
+
+ /**
+ * Hides the focus border around this component.
+ */
+ public void hideBorder() {
+ if (!borderShown)
+ return;
+ borderShown = false;
+ removeGroup(GROUP_GUI_FOCUS);
+ }
+
+ @Override
+ public boolean keyPressed(final KeyEvent event, final ViewPanel viewPanel) {
+ if (event.getKeyChar() == KeyboardHelper.ESC)
+ viewPanel.getKeyboardFocusStack().popFocusOwner();
+ return true;
+ }
+
+ @Override
+ public boolean keyReleased(final KeyEvent event, final ViewPanel viewPanel) {
+ return false;
+ }
+
+ @Override
+ public boolean mouseClicked(int button) {
+ // Direct-call path (no dispatch, no focus stack supplied). Only
+ // works for components constructed with a live panel; headless-built
+ // components (null panel) ignore the click instead of throwing.
+ if (viewPanel == null)
+ return false;
+ return mouseClicked(button, Double.NaN, Double.NaN,
+ viewPanel.getKeyboardFocusStack());
+ }
+
+ @Override
+ public boolean mouseClicked(final int button, final double textureU,
+ final double textureV,
+ final KeyboardFocusStack focusStack) {
+ if (button == MouseEvent.BUTTON_MIDDLE) {
+ // middle click releases keyboard focus, like ESC
+ focusStack.popFocusOwner();
+ return true;
+ }
+ return focusStack.pushFocusOwner(this);
+ }
+
+ @Override
+ public boolean mouseWheelMoved(final int verticalUnits,
+ final int horizontalUnits) {
+ // a focused GUI component owns the scroll wheel (the camera must
+ // not move while a component is focused); subclasses like the
+ // terminal and browser panels forward the scroll to their app
+ return true;
+ }
+
+ @Override
+ public boolean mouseEntered() {
+ return false;
+ }
+
+ @Override
+ public boolean mouseExited() {
+ return false;
+ }
+
+ private void setDimensions(final Point3D size) {
+ containingBox.setBoxSize(size);
+ }
+
+ private void showBorder() {
+ if (borderShown)
+ return;
+ borderShown = true;
+ addShape(getBorders(), GROUP_GUI_FOCUS);
+ }
+
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui;
+
+import static java.lang.Integer.compare;
+
+/**
+ * A pointer to a character in a text using row and column.
+ * <p>
+ * It can be used to represent a cursor position in a text.
+ * Also, it can be used to represent beginning and end of a selection.
+ */
+public class TextPointer implements Comparable<TextPointer> {
+
+ /**
+ * The row of the character. Starts from 0.
+ */
+ public int row;
+
+ /**
+ * The column of the character. Starts from 0.
+ */
+ public int column;
+
+ /**
+ * Creates a text pointer at position (0, 0).
+ */
+ public TextPointer() {
+ this(0, 0);
+ }
+
+ /**
+ * Creates a text pointer at the specified row and column.
+ *
+ * @param row the row index (0-based)
+ * @param column the column index (0-based)
+ */
+ public TextPointer(final int row, final int column) {
+ this.row = row;
+ this.column = column;
+ }
+
+ /**
+ * Creates a text pointer by copying another text pointer.
+ *
+ * @param parent the text pointer to copy
+ */
+ public TextPointer(final TextPointer parent) {
+ this(parent.row, parent.column);
+ }
+
+ @Override
+ public boolean equals(final Object o) {
+ if (o == null) return false;
+
+ return o instanceof TextPointer && compareTo((TextPointer) o) == 0;
+ }
+
+ @Override
+ public int hashCode() {
+ int result = row;
+ result = 31 * result + column;
+ return result;
+ }
+
+ /**
+ * Compares this pointer to another pointer.
+ *
+ * @param textPointer The pointer to compare to.
+ * @return <ul>
+ * <li>-1 if this pointer is smaller than the argument pointer.</li>
+ * <li>0 if they are equal.</li>
+ * <li>1 if this pointer is bigger than the argument pointer.</li>
+ * </ul>
+ */
+ @Override
+ public int compareTo(final TextPointer textPointer) {
+
+ if (row < textPointer.row)
+ return -1;
+ if (row > textPointer.row)
+ return 1;
+
+ return compare(column, textPointer.column);
+ }
+
+ /**
+ * Checks if this pointer is between the argument pointers.
+ * <p>
+ * This pointer is considered to be between the pointers if it is bigger or equal to the start pointer
+ * and smaller than the end pointer.
+ *
+ * @param start The start pointer.
+ * @param end The end pointer.
+ * @return True if this pointer is between the specified pointers.
+ */
+ public boolean isBetween(final TextPointer start, final TextPointer end) {
+
+ if (start == null)
+ return false;
+
+ if (end == null)
+ return false;
+
+ // Make sure that start is smaller than end.
+ TextPointer smaller;
+ TextPointer bigger;
+
+ if (end.compareTo(start) >= 0) {
+ smaller = start;
+ bigger = end;
+ } else {
+ smaller = end;
+ bigger = start;
+ }
+
+ // Check if this pointer is between the specified pointers.
+ return (compareTo(smaller) >= 0) && (bigger.compareTo(this) > 0);
+ }
+
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui;
+import eu.svjatoslav.aukio.e3d.diag.ThreadActivityRecorder;
+
+import javax.swing.*;
+import java.awt.*;
+import java.awt.event.AdjustmentEvent;
+import java.awt.event.AdjustmentListener;
+import java.awt.event.MouseWheelEvent;
+import java.awt.event.MouseWheelListener;
+
+/**
+ * Per-thread activity timeline for the Developer Tools window — the
+ * software-renderer equivalent of a GPU frame profiler's occupancy view.
+ *
+ * <p>One row per worker thread, plus the render and present threads
+ * pinned to the top. Worker rows are labeled CPU 01..N in a stable
+ * order. Time on the X axis, interval kind as color. Black gaps are
+ * idle time — the spots
+ * where a core had no work, which is what this view exists to find. In a
+ * perfectly pipelined renderer every worker row is solid: when transform
+ * of frame N+1 (yellow-green) starts appearing inside paint of frame N
+ * (blue), the pipeline is overlapping as intended.</p>
+ *
+ * <p>While recording, the view shows a live-scrolling window of the last
+ * ~100 ms. After Record is toggled off the capture freezes and can be
+ * scrolled back through the whole retained history (the ring buffer
+ * keeps roughly the last 10+ seconds at typical task rates) with the
+ * scrollbar or the mouse wheel.</p>
+ *
+ * <p>Reads the {@link ThreadActivityRecorder} ring buffer directly on
+ * repaint; recording itself is toggled from the parent panel.</p>
+ */
+public class ThreadTimelineComponent extends JComponent {
+
+ /** Time window shown, in nanoseconds. Adjustable with ctrl+wheel. */
+ private long windowNanos = 100_000_000L;
+
+ /** Minimum and maximum zoom window, nanoseconds. */
+ private static final long MIN_WINDOW_NANOS = 5_000_000L;
+ private static final long MAX_WINDOW_NANOS = 2_000_000_000L;
+
+ private static final int ROW_HEIGHT = 11;
+ private static final int LABEL_WIDTH = 64;
+ private static final int LEGEND_HEIGHT = 16;
+ /** Rows the component reserves height for, so all workers + render fit. */
+ private static final int RESERVED_ROWS = 26;
+
+ /** Colors per recorded kind: three frame parities each for transform/paint/bin, then 9..11. */
+ private static final Color[] KIND_COLORS = {
+ new Color(0x2E, 0xCC, 0x40), // transform, frame%3=0 — green
+ new Color(0xB8, 0xD9, 0x00), // transform, frame%3=1 — yellow-green
+ new Color(0x6B, 0x8E, 0x23), // transform, frame%3=2 — olive
+ new Color(0x00, 0x74, 0xD9), // paint, frame%3=0 — blue
+ new Color(0xF0, 0x12, 0xBE), // paint, frame%3=1 — magenta
+ new Color(0xB1, 0x0D, 0xC9), // paint, frame%3=2 — purple
+ new Color(0x39, 0xCC, 0xCC), // binning, frame%3=0 — cyan
+ new Color(0x00, 0x8B, 0x8B), // binning, frame%3=1 — dark cyan
+ new Color(0x00, 0x70, 0x70), // binning, frame%3=2 — teal
+ new Color(0xA0, 0xA0, 0xA0), // render-thread serial — gray
+ new Color(0x8B, 0x00, 0x00), // render-thread waiting— dark red
+ new Color(0xFF, 0xFF, 0xFF), // blit — white
+ new Color(0xFF, 0x85, 0x1B), // continuation (drain/sort/bin) — orange
+ new Color(0x8B, 0x45, 0x13), // drain+merge — brown
+ new Color(0xFF, 0xD7, 0x00), // depth sort — gold
+ };
+
+ private static final String[] LEGEND = {
+ "transform f0", "transform f1", "transform f2",
+ "paint f0", "paint f1", "paint f2",
+ "bin f0", "bin f1", "bin f2",
+ "render serial", "blocked", "blit", "sort+bin", "drain", "sort",
+ };
+
+ /**
+ * Scrollbar for navigating a frozen capture, in milliseconds scrolled
+ * back from the latest recorded interval. Owned here so the component
+ * can keep the model in sync with the capture length; the parent
+ * panel adds it below the timeline.
+ */
+ public final JScrollBar scrollBar = new JScrollBar(JScrollBar.HORIZONTAL, 0, 100, 0, 100);
+
+ /**
+ * How far back from the latest recorded interval the window ends,
+ * nanoseconds. Always 0 (live edge) while recording; user-adjustable
+ * on a frozen capture.
+ */
+ private long scrollBackNanos = 0;
+
+ /** True while the scrollbar model is being updated programmatically. */
+ private boolean updatingScrollBar = false;
+
+ public ThreadTimelineComponent() {
+ setBackground(Color.BLACK);
+
+ scrollBar.addAdjustmentListener(new AdjustmentListener() {
+ @Override
+ public void adjustmentValueChanged(final AdjustmentEvent e) {
+ if (!updatingScrollBar) {
+ scrollBackNanos = scrollBar.getValue() * 1_000_000L;
+ repaint();
+ }
+ }
+ });
+
+ addMouseWheelListener(new MouseWheelListener() {
+ @Override
+ public void mouseWheelMoved(final MouseWheelEvent e) {
+ if (e.isControlDown()) {
+ // Zoom around the current window, x1.25 per notch
+ for (int i = 0; i < Math.abs(e.getWheelRotation()); i++) {
+ windowNanos = e.getWheelRotation() < 0
+ ? Math.max(MIN_WINDOW_NANOS, windowNanos * 4 / 5)
+ : Math.min(MAX_WINDOW_NANOS, windowNanos * 5 / 4);
+ }
+ } else {
+ if (ThreadActivityRecorder.isEnabled()) {
+ return; // live mode: nothing to scroll
+ }
+ scrollBackNanos = Math.max(0, scrollBackNanos
+ + e.getWheelRotation() * Math.max(1_000_000L, windowNanos / 10));
+ }
+ repaint();
+ }
+ });
+ }
+
+ @Override
+ public Dimension getPreferredSize() {
+ // Reserve full height up front: worker rows appear lazily as the
+ // pool starts, after the window has already been packed
+ return new Dimension(560, LEGEND_HEIGHT + RESERVED_ROWS * ROW_HEIGHT + 4);
+ }
+
+ @Override
+ protected void paintComponent(final Graphics graphics) {
+ super.paintComponent(graphics);
+ final Graphics2D g = (Graphics2D) graphics;
+ final int width = getWidth();
+ final int trackWidth = width - LABEL_WIDTH;
+
+ g.setColor(Color.BLACK);
+ g.fillRect(0, 0, width, getHeight());
+
+ // Legend
+ g.setFont(new Font(Font.MONOSPACED, Font.PLAIN, 9));
+ int legendX = 2;
+ for (int kind = 0; kind < LEGEND.length; kind++) {
+ g.setColor(KIND_COLORS[kind]);
+ g.fillRect(legendX, 3, 8, 8);
+ g.setColor(Color.LIGHT_GRAY);
+ g.drawString(LEGEND[kind], legendX + 10, 11);
+ legendX += 10 + g.getFontMetrics().stringWidth(LEGEND[kind]) + 10;
+ }
+
+ final boolean recording = ThreadActivityRecorder.isEnabled();
+ if (!recording && ThreadActivityRecorder.cursor() == 0) {
+ g.setColor(Color.GRAY);
+ g.drawString("recording off — press Record to capture thread activity",
+ LABEL_WIDTH + 8, LEGEND_HEIGHT + ROW_HEIGHT);
+ syncScrollBar(0, 0, true);
+ return;
+ }
+
+ final long[] starts = ThreadActivityRecorder.starts();
+ final long[] ends = ThreadActivityRecorder.ends();
+ final byte[] kinds = ThreadActivityRecorder.kinds();
+ final byte[] rows = ThreadActivityRecorder.rows();
+ final int capacity = ThreadActivityRecorder.capacity();
+
+ // Capture range: oldest retained interval to latest one
+ long latest = 0;
+ long oldest = Long.MAX_VALUE;
+ for (int i = 0; i < capacity; i++) {
+ if (starts[i] != 0) {
+ if (ends[i] > latest) {
+ latest = ends[i];
+ }
+ if (starts[i] < oldest) {
+ oldest = starts[i];
+ }
+ }
+ }
+ if (latest == 0) {
+ return;
+ }
+ if (oldest > latest - windowNanos) {
+ oldest = latest - windowNanos;
+ }
+
+ // Live edge while recording; frozen offset afterwards
+ if (recording) {
+ scrollBackNanos = 0;
+ }
+ final long maxScrollBack = latest - oldest - windowNanos;
+ scrollBackNanos = Math.max(0, Math.min(scrollBackNanos, Math.max(0, maxScrollBack)));
+
+ final long windowEnd = latest - scrollBackNanos;
+ final long windowStart = windowEnd - windowNanos;
+ final double nanosPerPixel = (double) windowNanos / trackWidth;
+
+ final int rowCount = ThreadActivityRecorder.rowCount();
+
+ // Visual row order: "render" and "present" pinned to the top
+ // (they answer "where is the serial time" and "where is the
+ // display time"), workers below in recorder-row order. Recorder
+ // rows are assigned once per thread name, so this order is
+ // stable for the whole capture.
+ int renderRow = -1;
+ int presentRow = -1;
+ for (int row = 0; row < rowCount; row++) {
+ final String name = ThreadActivityRecorder.rowName(row);
+ if ("render".equals(name)) {
+ renderRow = row;
+ } else if ("present".equals(name)) {
+ presentRow = row;
+ }
+ }
+ final int[] visualOf = new int[rowCount];
+ int nextVisual = 0;
+ if (renderRow >= 0) {
+ visualOf[renderRow] = nextVisual++;
+ }
+ if (presentRow >= 0) {
+ visualOf[presentRow] = nextVisual++;
+ }
+ for (int row = 0; row < rowCount; row++) {
+ if (row != renderRow && row != presentRow) {
+ visualOf[row] = nextVisual++;
+ }
+ }
+
+ // Row labels and separators. Workers get sequential CPU numbers
+ // by visual position — the thread-name suffix (worker-27 etc.)
+ // is just a pool counter and carries no meaning.
+ int cpuNumber = 0;
+ final String[] labels = new String[rowCount];
+ for (int row = 0; row < rowCount; row++) {
+ if (row == renderRow) {
+ labels[row] = "render";
+ } else if (row == presentRow) {
+ labels[row] = "present";
+ } else {
+ labels[row] = String.format("CPU %02d", ++cpuNumber);
+ }
+ }
+ g.setColor(Color.DARK_GRAY);
+ for (int row = 0; row < rowCount; row++) {
+ final int y = LEGEND_HEIGHT + visualOf[row] * ROW_HEIGHT;
+ g.drawLine(LABEL_WIDTH, y + ROW_HEIGHT - 1, width, y + ROW_HEIGHT - 1);
+ g.setColor(Color.GRAY);
+ g.drawString(labels[row], 4, y + ROW_HEIGHT - 3);
+ g.setColor(Color.DARK_GRAY);
+ }
+
+ // Intervals
+ for (int i = 0; i < capacity; i++) {
+ final long t0 = starts[i];
+ if (t0 == 0 || ends[i] < windowStart || t0 > windowEnd) {
+ continue;
+ }
+ final int kind = kinds[i];
+ if (kind < 0 || kind >= KIND_COLORS.length) {
+ continue;
+ }
+ final int x0 = LABEL_WIDTH + (int) ((Math.max(t0, windowStart) - windowStart) / nanosPerPixel);
+ final int x1 = LABEL_WIDTH + (int) ((Math.min(ends[i], windowEnd) - windowStart) / nanosPerPixel);
+ g.setColor(KIND_COLORS[kind]);
+ g.fillRect(x0, LEGEND_HEIGHT + visualOf[rows[i]] * ROW_HEIGHT + 1,
+ Math.max(1, x1 - x0), ROW_HEIGHT - 2);
+ }
+
+ // Time grid: pick a tick spacing that keeps ~10 ticks in view
+ long tickSpacing = 1_000_000L; // 1 ms
+ while (windowNanos / tickSpacing > 20) {
+ tickSpacing *= 10;
+ }
+ while (windowNanos / tickSpacing < 5 && tickSpacing > 100_000L) {
+ tickSpacing /= 10;
+ }
+ g.setColor(new Color(40, 40, 40));
+ final long firstTick = (windowStart / tickSpacing + 1) * tickSpacing;
+ for (long tick = firstTick; tick < windowEnd; tick += tickSpacing) {
+ final int x = LABEL_WIDTH + (int) ((tick - windowStart) / nanosPerPixel);
+ g.drawLine(x, LEGEND_HEIGHT, x, LEGEND_HEIGHT + rowCount * ROW_HEIGHT);
+ }
+
+ // Window size + frozen-offset readout, bottom right of the track
+ g.setColor(Color.YELLOW);
+ final String readout = (windowNanos >= 1_000_000_000L
+ ? String.format("%.1f s", windowNanos / 1e9)
+ : String.format("%.0f ms", windowNanos / 1e6))
+ + (recording ? " live" : String.format(" -%.2f s", scrollBackNanos / 1e9));
+ g.drawString(readout, width - g.getFontMetrics().stringWidth(readout) - 6,
+ LEGEND_HEIGHT + rowCount * ROW_HEIGHT - 4);
+
+ syncScrollBar((int) (scrollBackNanos / 1_000_000L),
+ (int) (Math.max(0, maxScrollBack) / 1_000_000L) + (int) (windowNanos / 1_000_000L),
+ recording);
+ }
+
+ /**
+ * Pushes the current scroll state into the scrollbar model without
+ * feeding back into the adjustment listener.
+ *
+ * @param valueMs current scroll-back offset in milliseconds
+ * @param maxMs maximum scroll-back offset plus window size
+ * @param disabled true to grey out the scrollbar (live recording)
+ */
+ private void syncScrollBar(final int valueMs, final int maxMs, final boolean disabled) {
+ final int visibleMs = Math.max(1, (int) (windowNanos / 1_000_000L));
+ updatingScrollBar = true;
+ try {
+ scrollBar.setEnabled(!disabled && maxMs > visibleMs);
+ scrollBar.setValues(Math.min(valueMs, maxMs), visibleMs, 0, Math.max(visibleMs, maxMs));
+ } finally {
+ updatingScrollBar = false;
+ }
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui;
+
+import javax.swing.*;
+import java.awt.*;
+import java.awt.event.ComponentEvent;
+import java.awt.event.ComponentListener;
+import java.awt.event.WindowEvent;
+import java.awt.event.WindowListener;
+
+/**
+ * Convenience window (JFrame) that creates and hosts a {@link ViewPanel} for 3D rendering.
+ *
+ * <p>This is the simplest way to get a 3D view up and running. The frame starts
+ * maximized, enforces a minimum size of 400x400, and handles window lifecycle
+ * events (minimizing, restoring, closing) automatically.</p>
+ *
+ * <p><b>Quick start:</b></p>
+ * <pre>{@code
+ * // Create a window with a 3D view
+ * ViewFrame frame = new ViewFrame();
+ *
+ * // Access the view panel to add shapes and configure the scene
+ * ViewPanel viewPanel = frame.getViewPanel();
+ * viewPanel.getRootShapeCollection().addShape(
+ * new WireframeCube(new Point3D(0, 0, 200), 50,
+ * new LineAppearance(5, Color.GREEN))
+ * );
+ *
+ * // To close programmatically:
+ * frame.exit();
+ * }</pre>
+ *
+ * @see ViewPanel the embedded 3D rendering panel
+ */
+public class ViewFrame extends JFrame implements WindowListener {
+
+ private static final long serialVersionUID = -7037635097739548470L;
+
+ /** The embedded 3D view panel. */
+ private final ViewPanel viewPanel;
+
+ /** Whether the frame is currently in fullscreen exclusive mode. */
+ private boolean fullscreen = false;
+
+ /** Saved window bounds before entering fullscreen, used to restore on exit. */
+ private Rectangle previousBounds;
+
+ /** Saved extended state before entering fullscreen. */
+ private int previousExtendedState;
+
+ /**
+ * Creates a new maximized window with a 3D view.
+ */
+ public ViewFrame() {
+ this("3D engine", -1, -1, true);
+ }
+
+ /**
+ * Creates a new maximized window with a 3D view and custom title.
+ *
+ * @param title the window title to display
+ */
+ public ViewFrame(final String title) {
+ this(title, -1, -1, true);
+ }
+
+ /**
+ * Creates a new window with a 3D view at the specified size.
+ *
+ * @param width window width in pixels, or -1 for default
+ * @param height window height in pixels, or -1 for default
+ */
+ public ViewFrame(final int width, final int height) {
+ this("3D engine", width, height, false);
+ }
+
+ /**
+ * Creates a new window with a 3D view at the specified size with a custom title.
+ *
+ * @param title the window title to display
+ * @param width window width in pixels, or -1 for default
+ * @param height window height in pixels, or -1 for default
+ */
+ public ViewFrame(final String title, final int width, final int height) {
+ this(title, width, height, false);
+ }
+
+ private ViewFrame(final String title, final int width, final int height, final boolean maximize) {
+ setTitle(title);
+
+ addWindowListener(new java.awt.event.WindowAdapter() {
+ @Override
+ public void windowClosing(final java.awt.event.WindowEvent e) {
+ exit();
+ }
+ });
+
+ viewPanel = new ViewPanel();
+
+ add(getViewPanel());
+
+ if (width > 0 && height > 0) {
+ setSize(width, height);
+ } else {
+ setSize(800, 600);
+ }
+
+ if (maximize) {
+ setExtendedState(JFrame.MAXIMIZED_BOTH);
+ }
+ setVisible(true);
+ validate();
+
+ addResizeListener();
+ addWindowListener(this);
+ }
+
+ private void addResizeListener() {
+ addComponentListener(new ComponentListener() {
+ // This method is called after the component's size changes
+ @Override
+ public void componentHidden(final ComponentEvent e) {
+ }
+
+ @Override
+ public void componentMoved(final ComponentEvent e) {
+ }
+
+ @Override
+ public void componentResized(final ComponentEvent evt) {
+
+ final Component c = (Component) evt.getSource();
+
+ // Get new size
+ final Dimension newSize = c.getSize();
+
+ boolean sizeFixed = false;
+
+ if (newSize.width < 400) {
+ newSize.width = 400;
+ sizeFixed = true;
+ }
+
+ if (newSize.height < 400) {
+ newSize.height = 400;
+ sizeFixed = true;
+ }
+
+ if (sizeFixed)
+ setSize(newSize);
+
+ }
+
+ @Override
+ public void componentShown(final ComponentEvent e) {
+ viewPanel.repaintDuringNextViewUpdate();
+ }
+
+ });
+ }
+
+ /**
+ * Exit the application.
+ */
+ public void exit() {
+ if (getViewPanel() != null) {
+ getViewPanel().stop();
+ getViewPanel().setEnabled(false);
+ getViewPanel().setVisible(false);
+ }
+ dispose();
+ }
+
+ @Override
+ public java.awt.Dimension getPreferredSize() {
+ return new java.awt.Dimension(640, 480);
+ }
+
+ /**
+ * Returns the embedded {@link ViewPanel} for adding shapes and configuring the scene.
+ *
+ * @return the view panel contained in this frame
+ */
+ public ViewPanel getViewPanel() {
+ return viewPanel;
+ }
+
+ /**
+ * Returns whether the frame is currently in fullscreen exclusive mode.
+ *
+ * @return {@code true} if the frame is in fullscreen exclusive mode
+ */
+ public boolean isFullscreen() {
+ return fullscreen;
+ }
+
+ /**
+ * Enters or exits fullscreen exclusive mode (FSEM).
+ *
+ * <p>Fullscreen always targets the screen the window is currently
+ * placed on (its {@link GraphicsConfiguration#getDevice()}), so a
+ * window dragged onto e.g. XR glasses goes fullscreen there, not on
+ * the primary monitor. The default screen device is only a fallback
+ * for a not-yet-displayed frame.</p>
+ *
+ * <p>When entering fullscreen, the current window bounds and extended state are
+ * saved so they can be restored on exit. The frame is passed to the screen
+ * device as the fullscreen window, which automatically removes decorations and
+ * covers the entire screen. No explicit {@code setUndecorated()} call is needed —
+ * in fact, calling it would be harmful because it requires {@code dispose()} which
+ * destroys the Canvas and its BufferStrategy.</p>
+ *
+ * <p>When exiting fullscreen, the frame is released from the screen device,
+ * decorations are restored automatically, and previous bounds/extended state
+ * are restored.</p>
+ *
+ * <p>This method is idempotent: setting fullscreen to its current value
+ * is a no-op and returns {@code true}.</p>
+ *
+ * @param on {@code true} to enter fullscreen, {@code false} to exit fullscreen
+ * @return {@code true} if the state changed or was already as requested, {@code false}
+ * if the transition could not be performed (e.g. unsupported graphics device)
+ */
+ public boolean setFullscreen(final boolean on) {
+ if (this.fullscreen == on)
+ return true;
+
+ GraphicsDevice device = null;
+ final GraphicsConfiguration configuration = getGraphicsConfiguration();
+ if (configuration != null)
+ device = configuration.getDevice();
+ if (device == null)
+ device = GraphicsEnvironment.getLocalGraphicsEnvironment()
+ .getDefaultScreenDevice();
+
+ if (!device.isFullScreenSupported())
+ return false;
+
+ try {
+ if (on) {
+ // Save current state before entering fullscreen
+ previousBounds = getBounds();
+ previousExtendedState = getExtendedState();
+
+ // GraphicsDevice.setFullScreenWindow() automatically removes
+ // decorations when entering FSEM and restores them on exit.
+ // Do NOT call setUndecorated() here — it requires the frame to be
+ // non-displayable (dispose first) which destroys the Canvas and
+ // its BufferStrategy, breaking the render thread.
+ device.setFullScreenWindow(this);
+ fullscreen = true;
+ } else {
+ // Exit fullscreen exclusive mode.
+ // Decorations are restored automatically by the graphics device.
+ device.setFullScreenWindow(null);
+
+ // Restore previous bounds and extended state
+ if (previousBounds != null) {
+ setBounds(previousBounds);
+ }
+ setExtendedState(previousExtendedState);
+
+ fullscreen = false;
+
+ // Trigger a repaint since the rendering surface changed
+ viewPanel.repaintDuringNextViewUpdate();
+ }
+ } catch (final Exception e) {
+ // Something went wrong — revert if we were trying to enter
+ if (on) {
+ try {
+ device.setFullScreenWindow(null);
+ if (previousBounds != null)
+ setBounds(previousBounds);
+ setExtendedState(previousExtendedState);
+ } catch (final Exception ignored) {
+ }
+ }
+ return false;
+ }
+
+ return true;
+ }
+
+ /**
+ * Toggles between fullscreen exclusive mode and windowed mode.
+ *
+ * <p>Equivalent to {@code setFullscreen(!isFullscreen())}.</p>
+ *
+ * @return {@code true} if the toggle succeeded
+ * @see #setFullscreen(boolean)
+ * @see #isFullscreen()
+ */
+ public boolean toggleFullscreen() {
+ return setFullscreen(!fullscreen);
+ }
+
+ @Override
+ public void windowActivated(final WindowEvent e) {
+ viewPanel.repaintDuringNextViewUpdate();
+ viewPanel.requestFocus();
+ }
+
+ @Override
+ public void windowClosed(final WindowEvent e) {
+ }
+
+ @Override
+ public void windowClosing(final WindowEvent e) {
+ }
+
+ @Override
+ public void windowDeactivated(final WindowEvent e) {
+ }
+
+ /**
+ * Repaint the view when the window is deiconified.
+ *
+ * Deiconified means that the window is restored from minimized state.
+ */
+ @Override
+ public void windowDeiconified(final WindowEvent e) {
+ viewPanel.repaintDuringNextViewUpdate();
+ }
+
+ /**
+ * Do nothing when the window is iconified.
+ *
+ * Iconified means that the window is minimized.
+ * @param e the event to be processed
+ */
+ @Override
+ public void windowIconified(final WindowEvent e) {
+ }
+
+ @Override
+ public void windowOpened(final WindowEvent e) {
+ viewPanel.repaintDuringNextViewUpdate();
+ }
+
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui;
+import eu.svjatoslav.aukio.e3d.diag.DebugLogBuffer;
+import eu.svjatoslav.aukio.e3d.diag.ThreadActivityRecorder;
+import eu.svjatoslav.aukio.e3d.geometry.Camera;
+import eu.svjatoslav.aukio.e3d.renderer.raster.StereoEye;
+import eu.svjatoslav.aukio.e3d.renderer.raster.SegmentRenderingContext;
+import eu.svjatoslav.aukio.e3d.renderer.raster.RenderingContext;
+
+import eu.svjatoslav.aukio.e3d.diag.Diagnostics;
+import eu.svjatoslav.aukio.e3d.diag.EngineConfig;
+import eu.svjatoslav.aukio.e3d.diag.Telemetry;
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.gui.headtrack.HeadLookController;
+import eu.svjatoslav.aukio.e3d.gui.headtrack.HeadTracker;
+import eu.svjatoslav.aukio.e3d.gui.headtrack.RayNeoHid;
+import eu.svjatoslav.aukio.e3d.gui.spacemouse.SpaceNavigatorHid;
+import eu.svjatoslav.aukio.e3d.gui.humaninput.InputManager;
+import eu.svjatoslav.aukio.e3d.gui.humaninput.KeyboardFocusStack;
+import eu.svjatoslav.aukio.e3d.gui.humaninput.MouseEvent;
+import eu.svjatoslav.aukio.e3d.gui.humaninput.MouseInteractionController;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+import eu.svjatoslav.aukio.e3d.renderer.raster.ShapeCollection;
+import eu.svjatoslav.aukio.e3d.renderer.raster.lighting.LightingManager;
+
+import java.awt.*;
+import java.awt.event.ComponentAdapter;
+import java.awt.event.ComponentEvent;
+import java.awt.image.BufferStrategy;
+import java.util.Arrays;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * AWT Canvas that provides a 3D rendering surface with built-in camera navigation.
+ *
+ * <p>{@code ViewPanel} is the primary entry point for embedding the Aukio 3D engine into
+ * a Java application. It manages the render loop, maintains a scene graph
+ * ({@link ShapeCollection}), and handles user input for camera navigation.</p>
+ *
+ * <p>Uses {@link BufferStrategy} for efficient page-flipping and tear-free rendering.</p>
+ *
+ * <p><b>Quick start - creating a 3D view in a window:</b></p>
+ * <pre>{@code
+ * // Option 1: Use ViewFrame (creates a maximized JFrame for you)
+ * ViewFrame frame = new ViewFrame();
+ * ViewPanel viewPanel = frame.getViewPanel();
+ *
+ * // Option 2: Embed ViewPanel in your own window
+ * JFrame frame = new JFrame("My 3D App");
+ * ViewPanel viewPanel = new ViewPanel();
+ * frame.add(viewPanel);
+ * frame.setSize(800, 600);
+ * frame.setVisible(true);
+ *
+ * // Add shapes to the scene
+ * ShapeCollection scene = viewPanel.getRootShapeCollection();
+ * scene.addShape(new WireframeCube(
+ * new Point3D(0, 0, 200), 50,
+ * new LineAppearance(5, Color.GREEN)
+ * ));
+ *
+ * // Position the camera
+ * viewPanel.getCamera().setLocation(new Point3D(0, 0, -100));
+ *
+ * // Listen for frame updates (e.g., for animations)
+ * viewPanel.addFrameListener((panel, deltaMs) -> {
+ * // Called before each frame. Return true to force repaint.
+ * return false;
+ * });
+ * }</pre>
+ *
+ * <p><b>Architecture:</b></p>
+ * <ul>
+ * <li>A background render thread continuously generates frames at the target FPS</li>
+ * <li>The engine intelligently skips rendering when no visual changes are detected</li>
+ * <li>{@link FrameListener}s are notified before each potential frame, enabling animations</li>
+ * <li>Mouse/keyboard input is managed by {@link InputManager}</li>
+ * <li>Keyboard focus is managed by {@link KeyboardFocusStack}</li>
+ * </ul>
+ *
+ * @see ViewFrame convenience window wrapper
+ * @see ShapeCollection the scene graph
+ * @see Camera the camera/viewer
+ * @see FrameListener for per-frame callbacks
+ */
+public class ViewPanel extends Canvas {
+ private static final long serialVersionUID = 1683277888885045387L;
+ private static final int NUM_BUFFERS = 2;
+
+ /** The input manager handling mouse and keyboard events. */
+ private final InputManager inputManager = new InputManager(this);
+ /** The stack managing keyboard focus for GUI components. */
+ private final KeyboardFocusStack keyboardFocusStack;
+ /** The camera representing the viewer's position and orientation. */
+ private final Camera camera = new Camera();
+ /** Optional input devices (head tracker, 6DOF mouse) with hot-plug. */
+ private DeviceHotplug deviceHotplug;
+ /** The root shape collection containing all 3D shapes in the scene. */
+ private final ShapeCollection rootShapeCollection = new ShapeCollection();
+ /** The set of frame listeners notified before each frame. */
+ private final Set<FrameListener> frameListeners = ConcurrentHashMap.newKeySet();
+ /**
+ * Number of paint tiles per render thread. Tiles (not threads) are the
+ * unit of work: threads steal tiles off a shared ticket, so more tiles
+ * than threads lets fast threads pick up remaining tiles instead of
+ * idling behind a busy one. Measured 2026-09-04 (400-sphere scene,
+ * 1920x1080, HX 370): 10x oversampling beats 4x by ~15% and also
+ * beats pure horizontal bands; 16x adds a further win only on
+ * spatially clustered scenes.
+ */
+ private static final int TILES_PER_THREAD = 10;
+
+ /** Number of render threads. Can be changed at runtime via {@link #setNumRenderThreads(int)}. */
+ private volatile int numRenderThreads = defaultRenderThreadCount();
+ /**
+ * Executor for the parallel transform phase, sized to all available cores.
+ * Created lazily on the render thread; daemon threads so it never blocks JVM exit.
+ */
+ private ExecutorService transformExecutor = null;
+ /** The background color of the view. */
+ public Color backgroundColor = Color.BLACK;
+
+ /** Developer tools for this view panel. */
+ private final DeveloperTools developerTools = new DeveloperTools();
+ /** Debug log buffer for capturing diagnostic output. */
+ private final DebugLogBuffer debugLogBuffer = new DebugLogBuffer(10000);
+ /** The developer tools panel popup, or null if not currently shown. */
+ private DeveloperToolsPanel developerToolsPanel = null;
+
+ /**
+ * Global lighting manager for the scene.
+ * Contains all light sources and ambient light settings. Shaded polygons
+ * access this via the RenderingContext during paint(). Add lights here
+ * to illuminate the world.
+ */
+ private final LightingManager lightingManager = new LightingManager();
+
+ /** Progressive GI system, created by {@link #enableGlobalIllumination()}. */
+ private eu.svjatoslav.aukio.e3d.renderer.raster.gi.GlobalIllumination globalIllumination;
+
+ /**
+ * Stores milliseconds when the last frame was updated. This is needed to calculate the time delta between frames.
+ * Time delta is used to calculate smooth animation.
+ */
+ private long lastUpdateMillis = 0;
+
+ /** The current rendering context for the active frame. */
+ private RenderingContext renderingContext = null;
+
+ /**
+ * Triple-buffered frame contexts, indexed by pass counter modulo 3.
+ * While frame N is still being painted from one buffer, frame N+1
+ * already transforms into another, so paint threads never idle waiting
+ * for the transform phase and transform threads never wait for the
+ * last tile.
+ */
+ private final RenderingContext[] frameContexts = new RenderingContext[3];
+
+ /** Slot index (0..2) of the frame context currently being prepared. */
+ private int frameParity = 0;
+
+ /**
+ * Counts render passes (one per eye in stereo). A pass's projection
+ * buffer slot is {@code passCounter % 3}: with three slots, transform
+ * of pass P only conflicts with paint of pass P-3, so it can run
+ * while the two previous passes' paints are still in flight.
+ */
+ private long passCounter = 0;
+
+ /**
+ * Paint passes that were submitted to the shared executor but not yet
+ * awaited, oldest first. Depth stays at most 2: the pass being
+ * transformed now overlaps the previously submitted one, and freed
+ * workers flow from the tail of the older pass's tiles straight into
+ * the newer pass's tiles — consecutive passes' paints overlap on
+ * purpose (they write different parity framebuffers and read
+ * different parity vertex slots, so no ordering between them is
+ * required).
+ */
+ private final java.util.ArrayDeque<PendingPaint> pendingPaints = new java.util.ArrayDeque<>();
+
+ /**
+ * Mailbox holding the newest completed frame awaiting presentation.
+ * Only the latest frame is kept: when the display path (X server at
+ * 4K, tens of MB per blit) is slower than production, stale frames
+ * are dropped instead of piling up latency — swapchain "mailbox
+ * mode". The render thread never blocks on the display: it deposits
+ * here and the dedicated present thread does the blitting.
+ */
+ private final java.util.concurrent.atomic.AtomicReference<PresentJob> mailboxFrame =
+ new java.util.concurrent.atomic.AtomicReference<>();
+
+ /** Signals the present thread that a frame was deposited. */
+ private final java.util.concurrent.Semaphore presentSignal = new java.util.concurrent.Semaphore(0);
+
+ /** Daemon thread performing all BufferStrategy blits. */
+ private Thread presentThread;
+
+ /** Run flag for the present thread. */
+ private volatile boolean presentThreadRunning = false;
+
+ /**
+ * Maximum blits per second the present thread issues IN CAPPED-FPS
+ * MODE. Exists because the X server also dispatches input: flooding
+ * it with blits causes desktop-wide mouse/keyboard jitter. Override
+ * with {@code -Daukio3d.presentRate=N} for high-refresh displays.
+ *
+ * <p>In benchmark mode (targetFPS <= 0) pacing is DISABLED: the
+ * pacing sleep delays the presented frame's gate release, and since
+ * paint(F+3) awaits that gate before reusing F's framebuffer, pacing
+ * the present thread used to cap PRODUCTION to roughly
+ * 2×PRESENT_RATE_LIMIT_FPS (measured: unlimited-FPS mode
+ * locked to ~120 FPS with 18 workers 70% idle, 2026-09-06).</p>
+ */
+ private static final int PRESENT_RATE_LIMIT_FPS =
+ Integer.parseInt(System.getProperty("aukio3d.presentRate", "60"));
+
+ /**
+ * When false, each paint pass is awaited immediately after submission,
+ * restoring the old strictly-sequential phase order. Kill switch for
+ * benchmarking and regression hunting; also toggled at runtime from
+ * developer tools if needed.
+ */
+ private volatile boolean pipelineEnabled =
+ !"false".equalsIgnoreCase(System.getProperty("aukio3d.pipeline", "true"));
+
+ /**
+ * A paint pass whose tiles are still being worked on by the render
+ * executor. Awaited one pass later (software pipeline).
+ */
+ /** A completed frame plus the gate to fire once it is presented or dropped. */
+ private static final class PresentJob {
+ RenderingContext context;
+ java.util.concurrent.CountDownLatch gate;
+ }
+
+ private static class PendingPaint {
+ volatile CountDownLatch latch;
+ RenderingContext context;
+ volatile SegmentRenderingContext[] segmentContexts;
+ int eyeOffsetX;
+ int eyeWidth;
+ /** True when this pass completes its frame (blit becomes due). */
+ boolean lastPassOfFrame;
+
+ /** Global pass index at submission time (slot = index mod 3). */
+ long passIndex;
+
+ /** The frame's own present gate, fired when it is presented or dropped. */
+ java.util.concurrent.CountDownLatch frameGate;
+
+ /**
+ * Counted down by the pass's asynchronous continuation once the
+ * paint tasks have been submitted and {@link #latch} /
+ * {@link #segmentContexts} are published.
+ */
+ final java.util.concurrent.CountDownLatch ready = new java.util.concurrent.CountDownLatch(1);
+ }
+
+ /**
+ * Currently target frames per second rate for this view. Target FPS can be changed at runtime.
+ * 3D engine tries to be smart and only repaints screen when there are visible changes.
+ * A value of 0 or less means unlimited FPS (benchmark mode).
+ */
+ private volatile int targetFPS = 60;
+
+ /** Frames blitted in the current FPS measurement window (render thread only). */
+ private int fpsWindowFrames = 0;
+
+ /** Start of the current FPS measurement window, nanoseconds (render thread only). */
+ private long fpsWindowStartNanos = 0;
+
+ /** Most recently measured display rate (frames blitted per second). */
+ private volatile double measuredFPS = 0;
+
+ /**
+ * Set to true if it is known than next frame needs to be painted. Flag is cleared
+ * immediately after frame got updated.
+ */
+ private boolean viewRepaintNeeded = true;
+
+ /**
+ * Render thread that runs the continuous frame generation loop.
+ */
+ private Thread renderThread;
+
+ /**
+ * Flag to control whether the render thread should keep running.
+ */
+ private volatile boolean renderThreadRunning = false;
+
+ /** Timestamp for the next scheduled frame. */
+ private long nextFrameTime;
+
+ /**
+ * The most recently completed frame, retained so a bug report can
+ * include a screenshot of what the user was seeing. Set by
+ * {@link #presentFrame}; the buffer is reused by the pipeline, so
+ * consumers must copy it.
+ */
+ private volatile java.awt.image.BufferedImage lastFrameImage;
+
+ /** The buffer strategy for page-flipping rendering (also read by the present thread). */
+ private BufferStrategy bufferStrategy;
+
+ /** Whether the buffer strategy has been initialized. */
+ private boolean bufferStrategyInitialized = false;
+
+ /**
+ * Creates a new view panel with default settings.
+ */
+ public ViewPanel() {
+ frameListeners.add((panel, deltaMs) -> camera.onFrame(deltaMs));
+ frameListeners.add(inputManager);
+
+ // persistent log + telemetry (idempotent); the view telemetry
+ // source reports frame production stats
+ Diagnostics.install();
+ Telemetry.registerSource("view", () -> String.format(
+ "fps=%.1f targetFps=%d size=%dx%d renderThreads=%d",
+ getMeasuredFPS(), getTargetFPS(), getWidth(), getHeight(),
+ getNumRenderThreads()));
+
+ keyboardFocusStack = new KeyboardFocusStack(this);
+
+ initializeCanvas();
+ deviceHotplug = new DeviceHotplug(this);
+
+ // Set default ambient light for the scene
+ lightingManager.setAmbientLight(new Color(50, 50, 50));
+ addComponentListener(new ComponentAdapter() {
+ @Override
+ public void componentResized(final ComponentEvent e) {
+ viewRepaintNeeded = true;
+ startRenderThreadIfReady();
+ }
+
+ @Override
+ public void componentShown(final ComponentEvent e) {
+ viewRepaintNeeded = true;
+ startRenderThreadIfReady();
+ }
+ });
+ }
+
+ private void startRenderThreadIfReady() {
+ if (isShowing() && getWidth() > 0 && getHeight() > 0)
+ startRenderThread();
+ }
+
+ /**
+ * Returns the camera representing the viewer's position and orientation.
+ *
+ * @return the camera
+ */
+ public Camera getCamera() {
+ return camera;
+ }
+
+ /**
+ * Returns the keyboard focus stack, which manages which component receives
+ * keyboard input.
+ *
+ * @return the keyboard focus stack
+ */
+ public KeyboardFocusStack getKeyboardFocusStack() {
+ return keyboardFocusStack;
+ }
+
+ /**
+ * Returns the root shape collection (scene graph). Add your 3D shapes here
+ * to make them visible in the view.
+ *
+ * <pre>{@code
+ * viewPanel.getRootShapeCollection().addShape(myShape);
+ * }</pre>
+ *
+ * @return the root shape collection
+ */
+ public ShapeCollection getRootShapeCollection() {
+ return rootShapeCollection;
+ }
+
+ /**
+ * Returns the human input device (mouse/keyboard) event tracker.
+ *
+ * @return the HID event tracker
+ */
+ /**
+ * Returns the input manager handling mouse and keyboard events for this view.
+ *
+ * @return the input manager
+ */
+ public InputManager getInputManager() {
+ return inputManager;
+ }
+
+ /**
+ * Registers a listener that will be notified before each frame render.
+ * Listeners can trigger repaints by returning {@code true} from
+ * {@link FrameListener#onFrame}.
+ *
+ * @param listener the listener to add
+ * @see #removeFrameListener(FrameListener)
+ */
+ public void addFrameListener(final FrameListener listener) {
+ frameListeners.add(listener);
+ }
+
+ @Override
+ public Dimension getPreferredSize() {
+ return new Dimension(640, 480);
+ }
+
+ @Override
+ public Dimension getMinimumSize() {
+ return getPreferredSize();
+ }
+
+ @Override
+ public Dimension getMaximumSize() {
+ return getPreferredSize();
+ }
+
+ /**
+ * Returns the current rendering context for the active frame.
+ *
+ * @return the rendering context, or null if no frame is being rendered
+ */
+ public RenderingContext getRenderingContext() {
+ return renderingContext;
+ }
+
+ /**
+ * Returns the developer tools for this view panel.
+ *
+ * @return the developer tools
+ */
+ public DeveloperTools getDeveloperTools() {
+ return developerTools;
+ }
+
+ /**
+ * Returns the debug log buffer for this view panel.
+ *
+ * @return the debug log buffer
+ */
+ public DebugLogBuffer getDebugLogBuffer() {
+ return debugLogBuffer;
+ }
+
+ /**
+ * Returns the most recently completed frame, for bug report
+ * screenshots. The buffer belongs to the render pipeline and is
+ * reused — copy it before use. Null until the first frame completes.
+ *
+ * @return the last presented frame image, or null
+ */
+ public java.awt.image.BufferedImage getLastFrameImage() {
+ return lastFrameImage;
+ }
+
+ /**
+ * Returns the global lighting manager for the scene.
+ * Add light sources here to illuminate the world.
+ *
+ * @return the lighting manager
+ */
+ public LightingManager getLightingManager() {
+ return lightingManager;
+ }
+
+ /**
+ * Enables progressive global illumination with the default of 2
+ * dedicated low-priority CPU threads. GI is opt-in: without this call
+ * lighting behaves exactly as before. Shadows and bounced light fade in
+ * over the first seconds and keep adapting to scene changes.
+ *
+ * @return the running GI system
+ */
+ public eu.svjatoslav.aukio.e3d.renderer.raster.gi.GlobalIllumination enableGlobalIllumination() {
+ return enableGlobalIllumination(2);
+ }
+
+ /**
+ * Enables progressive global illumination with the given number of
+ * dedicated low-priority CPU threads. Calling again returns the
+ * already-running system.
+ *
+ * @param threadCount worker threads for ray tracing
+ * @return the running GI system
+ */
+ public synchronized eu.svjatoslav.aukio.e3d.renderer.raster.gi.GlobalIllumination enableGlobalIllumination(
+ final int threadCount) {
+ if (globalIllumination == null) {
+ globalIllumination = new eu.svjatoslav.aukio.e3d.renderer.raster.gi.GlobalIllumination(
+ rootShapeCollection, lightingManager, threadCount);
+ globalIllumination.start();
+ }
+ return globalIllumination;
+ }
+
+ /**
+ * Shows the developer tools panel, toggling it if already open.
+ * Called when F12 is pressed.
+ */
+ public void showDeveloperToolsPanel() {
+ if (developerToolsPanel != null && developerToolsPanel.isVisible()) {
+ developerToolsPanel.dispose();
+ developerToolsPanel = null;
+ return;
+ }
+
+ Frame parentFrame = null;
+ Container parent = getParent();
+ while (parent != null) {
+ if (parent instanceof Frame) {
+ parentFrame = (Frame) parent;
+ break;
+ }
+ parent = parent.getParent();
+ }
+
+ developerToolsPanel = new DeveloperToolsPanel(parentFrame, this, developerTools, debugLogBuffer);
+ developerToolsPanel.setVisible(true);
+ }
+
+ @Override
+ public void paint(final Graphics g) {
+ }
+
+ @Override
+ public void update(final Graphics g) {
+ }
+
+ private void initializeCanvas() {
+ setBackground(java.awt.Color.BLACK);
+ setFocusable(true);
+ // The canvas is the only focusable component in the frame; AWT
+ // focus traversal is meaningless here. Without this, AWT consumes
+ // Tab/Shift+Tab (and Ctrl+Tab) as traversal keys BEFORE they reach
+ // KeyListeners, so widgets (terminal, text editor Tab-indent)
+ // never see them.
+ setFocusTraversalKeysEnabled(false);
+ setIgnoreRepaint(true);
+ setVisible(true);
+ }
+
+ @Override
+ public void addNotify() {
+ super.addNotify();
+ requestFocus();
+ }
+
+ private void ensureBufferStrategy() {
+ if (bufferStrategyInitialized && bufferStrategy != null)
+ return;
+
+ if (!isDisplayable() || getWidth() <= 0 || getHeight() <= 0)
+ return;
+
+ try {
+ createBufferStrategy(NUM_BUFFERS);
+ bufferStrategy = getBufferStrategy();
+ if (bufferStrategy != null) {
+ bufferStrategyInitialized = true;
+ // Prime the buffer strategy with an initial show() to ensure it's ready
+ Graphics2D g = null;
+ try {
+ g = (Graphics2D) bufferStrategy.getDrawGraphics();
+ if (g != null) {
+ g.setColor(java.awt.Color.BLACK);
+ g.fillRect(0, 0, getWidth(), getHeight());
+ }
+ } finally {
+ if (g != null) g.dispose();
+ }
+ bufferStrategy.show();
+ java.awt.Toolkit.getDefaultToolkit().sync();
+ }
+ } catch (final Exception e) {
+ bufferStrategy = null;
+ bufferStrategyInitialized = false;
+ }
+ }
+
+
+ private void renderFrame() {
+ ensureBufferStrategy();
+
+ if (bufferStrategy == null || renderingContext == null) {
+ debugLogBuffer.log("[VIEWPANEL] renderFrame ABORT: bufferStrategy=" + bufferStrategy + ", renderingContext=" + renderingContext);
+ return;
+ }
+
+ ThreadActivityRecorder.setFrameParity(frameParity);
+
+ // Install this frame-use's present gate and capture the previous
+ // one: this frame's paint continuation will await the previous
+ // gate before writing pixels, so painting never overwrites a
+ // buffer the present thread is still blitting from. The frame's
+ // OWN gate travels with the PendingPaint to the deposit — the
+ // context field is reset again by the next frame reusing this
+ // context, long before this frame's flush reads it.
+ final java.util.concurrent.CountDownLatch previousGate = renderingContext.presentGate;
+ final java.util.concurrent.CountDownLatch frameGate = new java.util.concurrent.CountDownLatch(1);
+ renderingContext.presentGate = frameGate;
+
+ try {
+ // Triple-buffered software pipeline, one render pass per eye.
+ // Vertex state, aggregators and framebuffers cycle through 3
+ // slots, so transform(pass P) only needs paint(P-3) to be
+ // complete — it can run while the two previous passes' paints
+ // are still on the executor. Before each transform, completed
+ // paints are flushed (mouse hits, frame blit) and the render
+ // thread blocks ONLY if the pass P-3 paint is still running,
+ // which steady-state worker throughput prevents. Workers flow
+ // from one pass's tiles straight into the next pass's tiles
+ // with no gap: the next paint is always already queued.
+ if (stereoModeEnabled) {
+ final int eyeWidth = renderingContext.width / 2;
+ flushCompletedPasses(passCounter - 3);
+ final RenderingContext leftPass = transformPass(StereoEye.LEFT, eyeWidth, 0);
+ submitPaintPass(StereoEye.LEFT, eyeWidth, 0, false, leftPass, previousGate, frameGate);
+ flushCompletedPasses(passCounter - 3);
+ final RenderingContext rightPass = transformPass(StereoEye.RIGHT, eyeWidth, eyeWidth);
+ submitPaintPass(StereoEye.RIGHT, eyeWidth, eyeWidth, true, rightPass, previousGate, frameGate);
+ } else {
+ flushCompletedPasses(passCounter - 3);
+ final RenderingContext pass = transformPass(StereoEye.NONE, renderingContext.width, 0);
+ submitPaintPass(StereoEye.NONE, renderingContext.width, 0, true, pass, previousGate, frameGate);
+ }
+ frameParity = (frameParity + 1) % 3;
+ } catch (final Exception e) {
+ debugLogBuffer.log("[VIEWPANEL] renderFrame exception: " + e.getMessage());
+ e.printStackTrace();
+ bufferStrategyInitialized = false;
+ bufferStrategy = null;
+ }
+ }
+
+ /**
+ * Blits a finished frame buffer to the screen via the buffer strategy.
+ * The re-blit loop handles OS back-buffer recreation: contentsRestored()
+ * triggers when the OS recreates the back buffer (common during window
+ * creation); since the offscreen bufferedImage still contains the
+ * correct frame data, only a re-blit is needed, never a re-render.
+ *
+ * @param context the frame context whose bufferedImage is complete
+ */
+ /**
+ * Deposits a completed frame into the presentation mailbox and wakes
+ * the present thread. If the previous deposited frame has not been
+ * shown yet, it is dropped: displaying a stale frame when a newer one
+ * exists only adds latency.
+ *
+ * @param context the frame context whose buffer is complete
+ */
+ private void presentFrame(final RenderingContext context,
+ final java.util.concurrent.CountDownLatch frameGate) {
+ noteFrameBlitted(); // counts PRODUCED frames (benchmark rate)
+ lastFrameImage = context.bufferedImage;
+ final PresentJob job = new PresentJob();
+ job.context = context;
+ job.gate = frameGate;
+ final PresentJob dropped = mailboxFrame.getAndSet(job);
+ if (dropped != null) {
+ // Never shown: release its framebuffer for reuse immediately
+ dropped.gate.countDown();
+ }
+ presentSignal.release();
+ }
+
+ /**
+ * Present thread loop: takes the newest mailbox frame and blits it.
+ * All slow display-path work (33 MB drawImage at 4K, BufferStrategy
+ * show, Toolkit.sync round-trip to the X server) happens here, never
+ * on the render thread that feeds the worker pool.
+ *
+ * <p>Paced to the display rate IN CAPPED-FPS MODE: without a cap, an
+ * unlimited-FPS pipeline floods the X server with hundreds of 33 MB
+ * blits per second, and since the X server also processes mouse and
+ * keyboard, the whole desktop gets input jitter. In benchmark mode
+ * (targetFPS <= 0) pacing is skipped: the sleep would delay the
+ * presented frame's gate release, and gate backpressure
+ * (paint(F+3) awaits blit/drop of F) would cap production to the
+ * present rate — the opposite of what benchmark mode is for. Frames
+ * the present thread cannot keep up with are dropped from the
+ * mailbox at deposit time and their gates fire immediately.</p>
+ */
+ private void presentLoop() {
+ final long presentIntervalNanos = 1_000_000_000L / PRESENT_RATE_LIMIT_FPS;
+ long nextPresent = System.nanoTime();
+ while (presentThreadRunning) {
+ try {
+ presentSignal.acquire();
+ } catch (final InterruptedException e) {
+ break;
+ }
+ final PresentJob job = mailboxFrame.getAndSet(null);
+ if (job != null) {
+ // Only pace when the user asked for a capped frame rate.
+ if (targetFPS > 0) {
+ nextPresent += presentIntervalNanos;
+ final long sleep = nextPresent - System.nanoTime();
+ if (sleep > 0) {
+ try {
+ Thread.sleep(sleep / 1_000_000L, (int) (sleep % 1_000_000L));
+ } catch (final InterruptedException e) {
+ break;
+ }
+ } else if (sleep < -presentIntervalNanos) {
+ nextPresent = System.nanoTime(); // fell behind: resync
+ }
+ }
+ try {
+ blitFrame(job.context, job.gate);
+ } catch (final Throwable t) {
+ // A blit failure must NEVER kill this thread: every
+ // frame's present gate depends on it. Drop the buffer
+ // strategy; the render thread recreates it next frame.
+ debugLogBuffer.log("[VIEWPANEL] present failed: " + t);
+ bufferStrategyInitialized = false;
+ bufferStrategy = null;
+ } finally {
+ job.gate.countDown();
+ }
+ }
+ }
+ }
+
+ private void blitFrame(final RenderingContext context,
+ final java.util.concurrent.CountDownLatch gate) {
+ if (bufferStrategy == null)
+ return;
+ final boolean trace = ThreadActivityRecorder.isEnabled();
+ final long t0 = trace ? System.nanoTime() : 0;
+ try {
+ do {
+ Graphics2D g = null;
+ try {
+ g = (Graphics2D) bufferStrategy.getDrawGraphics();
+ if (g != null) {
+ // Use image observer to ensure proper image loading
+ g.drawImage(context.bufferedImage, 0, 0, this);
+ }
+ } catch (final Exception e) {
+ debugLogBuffer.log("[VIEWPANEL] Blit exception: " + e.getMessage());
+ break;
+ } finally {
+ if (g != null) g.dispose();
+ }
+ } while (bufferStrategy.contentsRestored());
+
+ // Release the framebuffer for reuse NOW: the draw loop above is
+ // the only part that reads context.bufferedImage. show() and
+ // Toolkit.sync() below touch only the BufferStrategy's own back
+ // buffer and the X connection — at 4920x2960 they cost ~16 ms
+ // (vs ~8 ms for the draw), and holding the frame's gate across
+ // them used to stall the paint pass waiting to reuse this
+ // buffer (measured 2026-09-06: gate hold ~24 ms, production
+ // capped at ~52 FPS). The present thread's finally-block still
+ // fires the gate as a backstop (countDown is idempotent).
+ gate.countDown();
+
+ if (bufferStrategy.contentsLost()) {
+ debugLogBuffer.log("[VIEWPANEL] Buffer contents LOST, reinitializing");
+ bufferStrategyInitialized = false;
+ bufferStrategy = null;
+ } else {
+ bufferStrategy.show();
+ java.awt.Toolkit.getDefaultToolkit().sync();
+ }
+ } finally {
+ if (trace) {
+ ThreadActivityRecorder.record(ThreadActivityRecorder.KIND_BLIT, t0, System.nanoTime());
+ }
+ }
+ }
+
+ /**
+ * Awaits the oldest pending paint pass (if any), processes its mouse
+ * hits, and schedules its frame buffer for blitting when it was the
+ * frame's last pass. Newer paint passes keep running meanwhile — the
+ * await only enforces the constraints that actually exist: vertex
+ * slot reuse (transform P+2 needs paint P done) and blit ordering.
+ */
+ private void flushPendingPaint() {
+ final PendingPaint pending = pendingPaints.poll();
+ if (pending == null)
+ return;
+
+ try {
+ final boolean trace = ThreadActivityRecorder.isEnabled();
+ final long t0 = trace ? System.nanoTime() : 0;
+ pending.ready.await();
+ final CountDownLatch paintLatch = pending.latch;
+ if (paintLatch != null) {
+ paintLatch.await();
+ }
+ if (trace) {
+ ThreadActivityRecorder.record(ThreadActivityRecorder.KIND_AWAIT, t0, System.nanoTime());
+ }
+ } catch (final InterruptedException e) {
+ Thread.currentThread().interrupt();
+ return;
+ }
+
+ // Hi-Z: fold this frame's depth into the occlusion pyramid the
+ // next frame's block culling runs against. Only on successful
+ // paint (segmentContexts null = the pass failed — keep the
+ // previous pyramid rather than folding in partial depth).
+ if (pending.segmentContexts != null
+ && pending.context.occlusionPyramid != null)
+ pending.context.occlusionPyramid.buildFrom(
+ pending.context.depth,
+ pending.context.width, pending.context.height);
+
+ // Only process mouse hits for the eye whose viewport contains the
+ // cursor. In stereo mode each eye sees a different camera position,
+ // so the same object may appear at different screen X in each eye.
+ // The cursor is in absolute screen coordinates and can only be in
+ // one eye's viewport; combining for the wrong eye would overwrite
+ // the correct hit with null.
+ final MouseEvent mouseEvent = pending.context.getMouseEvent();
+ final boolean mouseInThisEye = (mouseEvent == null)
+ || (mouseEvent.coordinate.x >= pending.eyeOffsetX
+ && mouseEvent.coordinate.x < pending.eyeOffsetX + pending.eyeWidth);
+ // segmentContexts is null when the pass's paint continuation
+ // failed (e.g. a transform chunk threw): the frame is skipped,
+ // but that must not kill the render loop with an NPE here.
+ if (mouseInThisEye && pending.segmentContexts != null) {
+ combineMouseResults(pending.segmentContexts, pending.context);
+ viewRepaintNeeded = pending.context.handlePossibleComponentMouseEvent(
+ getKeyboardFocusStack());
+ }
+
+ if (developerTools.showSegmentBoundaries) {
+ final RenderingContext context = pending.context;
+ final int tilesX = context.tilesX;
+ final int tilesY = context.tilesY;
+ final int tileH = context.height / tilesY;
+ final int tileW = pending.eyeWidth / tilesX;
+ final int[] pixels = context.pixels;
+ final int width = context.width;
+ final int height = context.height;
+ final int red = (255 << 16);
+ for (int ty = 1; ty < tilesY; ty++) {
+ final int offset = ty * tileH * width;
+ Arrays.fill(pixels, offset + pending.eyeOffsetX,
+ offset + pending.eyeOffsetX + pending.eyeWidth, red);
+ }
+ for (int tx = 1; tx < tilesX; tx++) {
+ final int x = pending.eyeOffsetX + tx * tileW;
+ for (int y = 0; y < height; y++)
+ pixels[y * width + x] = red;
+ }
+ }
+
+ if (pending.lastPassOfFrame) {
+ // Hand the completed frame to the present thread (mailbox:
+ // only the newest is shown). The render thread never blocks
+ // on the display; workers stay fed from the queue meanwhile.
+ presentFrame(pending.context, pending.frameGate);
+ }
+ }
+
+ /**
+ * Flushes every pending paint that is already complete, plus — when
+ * correctness demands — awaits older passes. Transform of pass P may
+ * only start once paint(P-3) is complete (vertex slot and aggregator
+ * cycle of 3); callers pass P-3 as {@code maxPassIndex}. Passes newer
+ * than that are flushed without blocking when their latch already
+ * reached zero, so completed frames are blitted as early as possible.
+ *
+ * @param maxPassIndex passes up to this index MUST be complete on return
+ */
+ private void flushCompletedPasses(final long maxPassIndex) {
+ while (true) {
+ final PendingPaint head = pendingPaints.peek();
+ if (head == null)
+ return;
+ if (head.passIndex > maxPassIndex
+ && (head.ready.getCount() > 0
+ || head.latch == null
+ || head.latch.getCount() > 0))
+ return; // still being prepared or painted; leave it queued
+ flushPendingPaint();
+ }
+ }
+
+ /**
+ * Clears a single tile's pixel area to the background color.
+ * Called by each render thread before painting shapes.
+ * The tile context carries exact X and Y bounds (X bounds also cover
+ * the stereo per-eye viewport).
+ *
+ * @param ctx the tile rendering context with X/Y bounds
+ */
+ private void clearSegmentPixels(final SegmentRenderingContext ctx) {
+ final int rgb = (backgroundColor.r << 16) | (backgroundColor.g << 8) | backgroundColor.b;
+ final int width = ctx.width;
+ final int[] pixels = ctx.pixels;
+
+ final int minX = ctx.renderMinX;
+ final int maxX = ctx.renderMaxX;
+
+ final float[] depth = ctx.depth;
+ for (int y = ctx.renderMinY; y < ctx.renderMaxY; y++) {
+ final int rowOffset = y * width;
+ Arrays.fill(pixels, rowOffset + minX, rowOffset + maxX, rgb);
+ Arrays.fill(depth, rowOffset + minX, rowOffset + maxX,
+ Float.NEGATIVE_INFINITY);
+ }
+ }
+
+ private void combineMouseResults(final SegmentRenderingContext[] segmentContexts,
+ final RenderingContext context) {
+ // All segments paint shapes back-to-front, and mouse hit detection
+ // happens before Y-bound clipping. So each segment should report the
+ // same "last hit" (frontmost shape under mouse). Just take the first non-null.
+ for (final SegmentRenderingContext ctx : segmentContexts) {
+ final MouseInteractionController hit = ctx.getSegmentMouseHit();
+ if (hit != null) {
+ context.setCurrentObjectUnderMouseCursor(hit,
+ ctx.getSegmentMouseHitU(), ctx.getSegmentMouseHitV());
+ return;
+ }
+ }
+ }
+
+ /**
+ * Calling these methods tells 3D engine that current 3D view needs to be
+ * repainted on first opportunity.
+ */
+ public void repaintDuringNextViewUpdate() {
+ viewRepaintNeeded = true;
+ }
+
+ /**
+ * Set target frames per second rate for this view. Target FPS can be changed at runtime.
+ * Use 0 or negative value for unlimited FPS (max performance mode for benchmarking).
+ *
+ * @param frameRate target frames per second rate for this view.
+ */
+ public void setFrameRate(final int frameRate) {
+ targetFPS = frameRate;
+ }
+
+ /**
+ * Returns the current target frames per second rate.
+ *
+ * @return target FPS; 0 or less means unlimited
+ */
+ public int getTargetFPS() {
+ return targetFPS;
+ }
+
+ /**
+ * Returns the measured production rate: frames completed per second,
+ * averaged over the last ~500 ms window. This is the benchmark number:
+ * how fast the pipeline produces frames, regardless of how quickly
+ * the display path presents them (the mailbox present thread may
+ * drop stale frames when the display is slower than production).
+ *
+ * @return measured frames per second
+ */
+ public double getMeasuredFPS() {
+ return measuredFPS;
+ }
+
+ /**
+ * Counts one blitted frame into the FPS measurement window.
+ * Called by the render thread after each completed blit.
+ */
+ private void noteFrameBlitted() {
+ fpsWindowFrames++;
+ final long now = System.nanoTime();
+ if (fpsWindowStartNanos == 0) {
+ fpsWindowStartNanos = now;
+ fpsWindowFrames = 0;
+ return;
+ }
+ final long elapsed = now - fpsWindowStartNanos;
+ if (elapsed >= 500_000_000L) {
+ measuredFPS = fpsWindowFrames * 1e9 / elapsed;
+ fpsWindowStartNanos = now;
+ fpsWindowFrames = 0;
+ }
+ }
+
+ /**
+ * Returns the current number of render threads.
+ *
+ * @return the number of render threads
+ */
+ public int getNumRenderThreads() {
+ return numRenderThreads;
+ }
+
+ /**
+ * Sets the number of render threads. Takes effect on the next frame.
+ * The executor service is recreated lazily when the render loop detects the change.
+ *
+ * @param count number of render threads (must be at least 1)
+ */
+ public void setNumRenderThreads(final int count) {
+ if (count < 1)
+ throw new IllegalArgumentException("Render thread count must be at least 1, got: " + count);
+ numRenderThreads = count;
+ viewRepaintNeeded = true;
+ }
+
+ // ------------------------------------------------------------------
+ // Stereo rendering
+ // ------------------------------------------------------------------
+
+ /**
+ * Default inter-pupillary distance in world units (centimeters).
+ * Human IPD ranges from ~5.5 to ~7.5 cm; 6.5 cm is the population median.
+ */
+ private static final double DEFAULT_STEREO_IPD = 6.5;
+
+ /** Inter-pupillary distance in world units, configurable at runtime. */
+ private double stereoIPD = EngineConfig.getIpdCm();
+
+ /** Whether side-by-side stereoscopic rendering is enabled. */
+ private boolean stereoModeEnabled = false;
+
+ /**
+ * Returns whether side-by-side stereoscopic rendering is currently enabled.
+ *
+ * @return {@code true} if stereo mode is active
+ */
+ public boolean isStereoModeEnabled() {
+ return stereoModeEnabled;
+ }
+
+ /**
+ * Enables or disables side-by-side stereoscopic rendering.
+ * When enabled, each frame renders two eye views side-by-side.
+ *
+ * @param enabled {@code true} to enable stereo mode, {@code false} to disable
+ */
+ public void setStereoModeEnabled(final boolean enabled) {
+ this.stereoModeEnabled = enabled;
+ viewRepaintNeeded = true;
+ }
+
+ /**
+ * Returns the current inter-pupillary distance used for stereo rendering.
+ *
+ * @return IPD in world units (centimeters)
+ */
+ public double getStereoIPD() {
+ return stereoIPD;
+ }
+
+ /**
+ * Sets the inter-pupillary distance for stereo rendering.
+ * Human IPD ranges from ~5.5 to ~7.5 cm; for XR glasses the optical
+ * IPD may differ from the user's anatomical IPD.
+ *
+ * @param ipd the inter-pupillary distance in world units (centimeters)
+ */
+ public void setStereoIPD(final double ipd) {
+ this.stereoIPD = ipd;
+ viewRepaintNeeded = true;
+ }
+
+ /**
+ * Runs the transform phase of a single eye pass: offsets the camera for
+ * the eye, updates the frame context viewport fields, transforms, sorts
+ * and tile-bins the scene. The pass's projection slot is
+ * {@code passCounter & 1}; its paint (submitted later by
+ * {@link #submitPaintPass}) reads the same slot from copies taken while
+ * it is still current.
+ *
+ * @param eye which eye to render
+ * @param eyeWidth width of the eye viewport in pixels
+ * @param eyeOffsetX X offset of the eye viewport within the full buffer
+ */
+ private RenderingContext transformPass(final StereoEye eye, final int eyeWidth, final int eyeOffsetX) {
+ final boolean trace = ThreadActivityRecorder.isEnabled();
+ final long t0 = trace ? System.nanoTime() : 0;
+ final Camera camera = getCamera();
+ final Point3D location = camera.getTransform().getTranslation();
+
+ final double originalX = location.x;
+ if (eye != StereoEye.NONE) {
+ final double ipdOffset = (eye == StereoEye.LEFT) ? -stereoIPD / 2.0 : stereoIPD / 2.0;
+ location.x += ipdOffset;
+ }
+
+ try {
+ // Independent per-pass context: the walk, its forked chunk
+ // tasks and the asynchronous sort/bin/paint continuation all
+ // read this copy, so the NEXT pass's setup (a new copy)
+ // cannot disturb work that is still in flight.
+ final RenderingContext passContext = new RenderingContext(renderingContext);
+ passContext.stereoEye = eye;
+ passContext.stereoViewportWidth = eyeWidth;
+ passContext.stereoViewportOffsetX = eyeOffsetX;
+ passContext.renderMinX = eyeOffsetX;
+ passContext.renderMaxX = eyeOffsetX + eyeWidth;
+ passContext.centerCoordinate.x = eyeWidth / 2.0;
+ passContext.projectionScale = eyeWidth / 3.0;
+ passContext.vertexSlot = (int) (passCounter % 3);
+
+ // Walks the tree and forks heavy composites into chunk tasks,
+ // but does NOT wait for them: draining happens inside the
+ // pass's continuation on a worker thread.
+ rootShapeCollection.transformShapesBegin(getCamera(), passContext);
+ return passContext;
+ } finally {
+ location.x = originalX;
+ if (trace) {
+ ThreadActivityRecorder.record(ThreadActivityRecorder.KIND_RENDER, t0, System.nanoTime());
+ }
+ }
+ }
+
+ /**
+ * Submits the paint phase of a single eye pass to the render executor
+ * and returns immediately (unless the pipeline kill switch is off).
+ * Tiles are work-stolen off a shared ticket; output is unaffected —
+ * every tile is still painted by exactly one thread, in fixed
+ * (Z, shapeId) order.
+ *
+ * @param eye which eye this pass renders
+ * @param eyeWidth width of the eye viewport in pixels
+ * @param eyeOffsetX X offset of the eye viewport within the buffer
+ * @param lastPassOfFrame true when this pass completes its frame
+ */
+ private void submitPaintPass(final StereoEye eye, final int eyeWidth, final int eyeOffsetX,
+ final boolean lastPassOfFrame, final RenderingContext passContext,
+ final java.util.concurrent.CountDownLatch previousGate,
+ final java.util.concurrent.CountDownLatch frameGate) {
+ final RenderingContext frameContext = renderingContext;
+ final int tilesX = frameContext.tilesX;
+ final int tilesY = frameContext.tilesY;
+ final int height = frameContext.height;
+ final int slot = passContext.vertexSlot;
+ final ExecutorService executor = getOrCreateTransformExecutor();
+
+ // Enqueue the pending-paint shell synchronously so pendingPaints
+ // stays in pass order; the continuation fills in the rest.
+ final PendingPaint pending = new PendingPaint();
+ pending.context = frameContext;
+ pending.eyeOffsetX = eyeOffsetX;
+ pending.eyeWidth = eyeWidth;
+ pending.lastPassOfFrame = lastPassOfFrame;
+ pending.passIndex = passCounter;
+ pending.frameGate = frameGate;
+ pendingPaints.addLast(pending);
+
+ passCounter++;
+
+ final int tracePaintKind = ThreadActivityRecorder.KIND_PAINT + ThreadActivityRecorder.frameParity();
+
+ // The whole rest of the pass is one asynchronous continuation on
+ // the shared executor: drain the transform chunks (a ForkJoinTask
+ // get() here work-steals instead of blocking), depth-sort on the
+ // same pool, bin per tile, then submit the paint ticket tasks.
+ // The render thread never waits for any of it.
+ executor.submit(() -> {
+ final boolean trace = ThreadActivityRecorder.isEnabled();
+ final long t0 = trace ? System.nanoTime() : 0;
+ try {
+ long ts = trace ? System.nanoTime() : 0;
+ rootShapeCollection.drainTransformShapes(passContext);
+ if (trace) {
+ ThreadActivityRecorder.record(ThreadActivityRecorder.KIND_DRAIN, ts, System.nanoTime());
+ ts = System.nanoTime();
+ }
+ // Present gate: never overwrite a buffer the present
+ // thread is still blitting from (frame F-3's contents).
+ // Fires instantly unless the display is >=3 frames behind.
+ // The timeout is insurance, not control flow: a present
+ // path failure must degrade to a torn frame, never to a
+ // frozen pipeline.
+ if (!previousGate.await(2, java.util.concurrent.TimeUnit.SECONDS)) {
+ debugLogBuffer.log("[VIEWPANEL] present gate timeout — presenting may be stuck");
+ }
+ if (trace) {
+ ThreadActivityRecorder.record(ThreadActivityRecorder.KIND_AWAIT, ts, System.nanoTime());
+ }
+ ts = trace ? System.nanoTime() : 0;
+ rootShapeCollection.sortShapes(slot, executor);
+ if (trace) {
+ ThreadActivityRecorder.record(ThreadActivityRecorder.KIND_SORT, ts, System.nanoTime());
+ }
+ rootShapeCollection.binShapesForTiles(slot, tilesX, tilesY,
+ eyeOffsetX, eyeWidth, height, executor);
+
+ final int tileW = eyeWidth / tilesX;
+ final int tileH = height / tilesY;
+ final int segments = tilesX * tilesY;
+ // In stereo the right eye's segment indices follow the left eye's
+ final int eyeBase = (eye == StereoEye.RIGHT) ? segments : 0;
+
+ final SegmentRenderingContext[] segmentContexts = new SegmentRenderingContext[segments];
+ for (int ty = 0; ty < tilesY; ty++) {
+ final int minY = ty * tileH;
+ final int maxY = (ty == tilesY - 1) ? height : (ty + 1) * tileH;
+ for (int tx = 0; tx < tilesX; tx++) {
+ final int minX = eyeOffsetX + tx * tileW;
+ final int maxX = (tx == tilesX - 1) ? eyeOffsetX + eyeWidth : minX + tileW;
+ final int index = ty * tilesX + tx;
+ final SegmentRenderingContext tileContext = new SegmentRenderingContext(
+ passContext, minY, maxY, eyeBase + index);
+ tileContext.vertexSlot = slot;
+ tileContext.renderMinX = minX;
+ tileContext.renderMaxX = maxX;
+ segmentContexts[index] = tileContext;
+ }
+ }
+
+ // Per-tile paint tasks on the fork/join pool: a worker
+ // finishing one tile immediately pulls ANY next queued
+ // work — another tile (of this or an adjacent frame's
+ // pass), a transform chunk, a continuation — so cores
+ // never idle waiting for a ticket-loop task to end.
+ final CountDownLatch paintLatch = new CountDownLatch(segments);
+
+ for (int s = 0; s < segments; s++) {
+ final int segmentIndex = s;
+ if (developerTools.renderAlternateSegments && (segmentIndex % 2 == 1)) {
+ paintLatch.countDown();
+ continue;
+ }
+ executor.submit(() -> {
+ final long pt0 = trace ? System.nanoTime() : 0;
+ try {
+ clearSegmentPixels(segmentContexts[segmentIndex]);
+ rootShapeCollection.paintShapes(segmentContexts[segmentIndex]);
+ } finally {
+ if (trace) {
+ ThreadActivityRecorder.record(tracePaintKind, pt0, System.nanoTime());
+ }
+ paintLatch.countDown();
+ }
+ });
+ }
+
+ pending.segmentContexts = segmentContexts;
+ pending.latch = paintLatch;
+ } catch (final Throwable t) {
+ debugLogBuffer.log("[VIEWPANEL] paint continuation failed: " + t);
+ t.printStackTrace();
+ } finally {
+ if (trace) {
+ ThreadActivityRecorder.record(ThreadActivityRecorder.KIND_PREP, t0, System.nanoTime());
+ }
+ pending.ready.countDown();
+ }
+ });
+
+ if (!pipelineEnabled) {
+ flushCompletedPasses(Long.MAX_VALUE);
+ }
+ }
+
+ // ------------------------------------------------------------------
+
+ /**
+ * Default number of paint segment threads: 75% of available CPU
+ * threads, clamped to at least 1 and at most (CPU threads - 1), so
+ * one thread always stays free for the rest of the system.
+ *
+ * @return the default render thread count
+ */
+ private static int defaultRenderThreadCount() {
+ final int cores = Runtime.getRuntime().availableProcessors();
+ return Math.max(1, Math.min((int) Math.round(cores * 0.75), cores - 1));
+ }
+
+ /**
+ * Returns the shared transform executor, creating it on first use.
+ * Called from the render thread only (no synchronization needed).
+ *
+ * @return the transform executor
+ */
+ private ExecutorService getOrCreateTransformExecutor() {
+ if (transformExecutor == null || transformExecutor.isShutdown()) {
+ final int threads = numRenderThreads;
+ final AtomicInteger workerCounter = new AtomicInteger();
+ // ForkJoinPool, not a fixed thread pool: the instrumented
+ // parallel merge sort and bin/merge copy tasks fork onto THIS
+ // pool (never the common pool), and a worker blocked in
+ // ForkJoinTask.get() (continuation draining transform chunks)
+ // work-steals other tasks instead of idling. asyncMode = FIFO
+ // submission queues, so older frames' work is preferred.
+ // Sized to the ALLOCATED thread count (75% of cores), not all
+ // cores: measured 2026-09-05 (UtilizationBench) that 24/24
+ // threads run only ~70% busy — GC/JIT/OS threads displace
+ // workers and stretch frame tails — while 18/18 stay ~83%+
+ // busy AND deliver higher FPS.
+ transformExecutor = new java.util.concurrent.ForkJoinPool(threads,
+ pool -> {
+ final java.util.concurrent.ForkJoinWorkerThread thread =
+ java.util.concurrent.ForkJoinPool.defaultForkJoinWorkerThreadFactory
+ .newThread(pool);
+ thread.setName("e3d-worker-" + workerCounter.getAndIncrement());
+ thread.setDaemon(true);
+ return thread;
+ }, null, true);
+ }
+ return transformExecutor;
+ }
+
+ /**
+ * Returns the active SpaceNavigator device, or null when no 6DOF
+ * mouse is currently connected.
+ */
+ public SpaceNavigatorHid getSpaceMouse() {
+ return deviceHotplug == null ? null : deviceHotplug.getSpaceMouse();
+ }
+
+ /**
+ * Returns the active head tracker, or null when no glasses are
+ * currently connected.
+ */
+ public HeadTracker getHeadTracker() {
+ return deviceHotplug == null ? null : deviceHotplug.getHeadTracker();
+ }
+
+ /**
+ * Stops rendering of this view.
+ */
+ public void stop() {
+ if (deviceHotplug != null) {
+ deviceHotplug.stop();
+ deviceHotplug = null;
+ }
+ if (globalIllumination != null) {
+ // Stop the GI sweep with the view: the worker threads trace
+ // rays against THIS view's scene, so after close they are pure
+ // CPU burn (observed 2026-09-20: 4 leaked threads at ~70% duty
+ // minutes after the demo window was gone).
+ globalIllumination.stop();
+ globalIllumination = null;
+ }
+ renderThreadRunning = false;
+ presentThreadRunning = false;
+ presentSignal.release();
+ final PresentJob dropped = mailboxFrame.getAndSet(null);
+ if (dropped != null) {
+ dropped.gate.countDown();
+ }
+ if (renderThread != null) {
+ // Interrupt BEFORE any executor teardown: the render thread may
+ // be parked in flushPendingPaint's paintLatch.await(), and
+ // shutdownNow() cancels queued paint tasks — a cancelled task
+ // never runs its finally countDown(), so the latch never fires
+ // and an uninterrupted join here hangs forever (observed
+ // 2026-09-20: close button dead, EDT stuck in this join).
+ renderThread.interrupt();
+ try {
+ renderThread.join();
+ } catch (InterruptedException e) {
+ Thread.currentThread().interrupt();
+ }
+ renderThread = null;
+ }
+ // Tear down the pipeline only with the render thread dead: clearing
+ // the deque and cancelling queued tasks while it was still flushing
+ // raced its peek/poll and orphaned the latches it awaited.
+ pendingPaints.clear();
+ if (transformExecutor != null) {
+ transformExecutor.shutdownNow();
+ }
+ }
+
+ /**
+ * Starts the render thread that continuously generates frames.
+ */
+ private synchronized void startRenderThread() {
+ if (renderThread != null)
+ return;
+
+ renderThreadRunning = true;
+ renderThread = new Thread(this::renderLoop, "e3d-render");
+ renderThread.setDaemon(true);
+ renderThread.start();
+
+ if (!presentThreadRunning) {
+ presentThreadRunning = true;
+ presentThread = new Thread(this::presentLoop, "e3d-present");
+ presentThread.setDaemon(true);
+ presentThread.start();
+ }
+ }
+
+ /**
+ * Main render loop that generates frames continuously.
+ * Supports both unlimited FPS and fixed FPS modes with dynamic sleep adjustment.
+ */
+ private void renderLoop() {
+ nextFrameTime = System.currentTimeMillis();
+
+ while (renderThreadRunning) {
+ try {
+ ensureThatViewIsUpToDate();
+ } catch (final Exception e) {
+ e.printStackTrace();
+ }
+
+ if (maintainTargetFps()) break;
+ }
+ }
+
+ /**
+ * Ensures that the rendering process maintains the target frames per second (FPS)
+ * by dynamically adjusting the thread sleep duration.
+ *
+ * @return {@code true} if the thread was interrupted while sleeping, otherwise {@code false}.
+ */
+ private boolean maintainTargetFps() {
+ if (targetFPS <= 0) return false;
+
+ long now = System.currentTimeMillis();
+
+ nextFrameTime += 1000L / targetFPS;
+
+ // If we've fallen behind, reset to now instead of trying to catch up
+ if (nextFrameTime < now)
+ nextFrameTime = now;
+
+ long sleepTime = nextFrameTime - now;
+ if (sleepTime > 0) {
+ try {
+ Thread.sleep(sleepTime);
+ } catch (InterruptedException e) {
+ Thread.currentThread().interrupt();
+ return true;
+ }
+ }
+ return false;
+ }
+
+ /**
+ * This method is executed by periodic timer task, in frequency according to
+ * defined frame rate.
+ * <p>
+ * It tells view to update itself. View can decide if actual re-rendering of
+ * graphics is needed.
+ */
+ void ensureThatViewIsUpToDate() {
+ maintainRenderingContext();
+
+ final int millisecondsPassedSinceLastUpdate = getMillisecondsPassedSinceLastUpdate();
+
+ boolean renderFrame = notifyFrameListeners(millisecondsPassedSinceLastUpdate);
+
+ // Unlimited FPS is benchmark mode: render continuously even when
+ // the scene reports no changes, so the measured rate reflects
+ // maximum achievable throughput.
+ if (targetFPS <= 0) {
+ renderFrame = true;
+ }
+
+ if (viewRepaintNeeded) {
+ viewRepaintNeeded = false;
+ renderFrame = true;
+ }
+
+ // abort rendering if window size is invalid
+ if ((getWidth() > 0) && (getHeight() > 0) && renderFrame) {
+ renderFrame();
+ } else {
+ // No new frame: make sure the last submitted paint passes
+ // still get awaited, mouse-processed and blitted.
+ flushCompletedPasses(Long.MAX_VALUE);
+ }
+ }
+
+ private void maintainRenderingContext() {
+ int panelWidth = getWidth();
+ int panelHeight = getHeight();
+
+ if (panelWidth <= 0 || panelHeight <= 0) {
+ if (frameContexts[0] != null) {
+ frameContexts[0].dispose();
+ frameContexts[1].dispose();
+ frameContexts[2].dispose();
+ frameContexts[0] = null;
+ frameContexts[1] = null;
+ frameContexts[2] = null;
+ renderingContext = null;
+ pendingPaints.clear();
+ }
+ return;
+ }
+
+ // create new rendering contexts if window size has changed OR the
+ // tile grid has changed (thread count, stereo toggle)
+ final int viewportCount = stereoModeEnabled ? 2 : 1;
+ final int viewportWidth = panelWidth / viewportCount;
+ // Total tiles ~= 10x paint threads (work-stealing granularity);
+ // split into roughly square tiles: squares minimize boundary
+ // crossings, i.e. how many tiles each shape overlaps
+ final int targetTiles = Math.max(1, numRenderThreads * TILES_PER_THREAD);
+ final int tilesX = Math.max(1, Math.min(viewportWidth, (int) Math.round(
+ Math.sqrt(targetTiles * (double) viewportWidth / panelHeight))));
+ final int tilesY = Math.max(1, Math.min(panelHeight,
+ (int) Math.round((double) targetTiles / tilesX)));
+ if ((frameContexts[0] == null)
+ || (frameContexts[0].width != panelWidth)
+ || (frameContexts[0].height != panelHeight)
+ || (frameContexts[0].tilesX != tilesX)
+ || (frameContexts[0].tilesY != tilesY)
+ || (frameContexts[0].viewportCount != viewportCount)) {
+ // The pending paints still work on the old buffers; let them
+ // finish before disposing the contexts they write into.
+ flushCompletedPasses(Long.MAX_VALUE);
+ final PresentJob droppedJob = mailboxFrame.getAndSet(null);
+ if (droppedJob != null) {
+ droppedJob.gate.countDown();
+ }
+ for (int parity = 0; parity < 3; parity++) {
+ if (frameContexts[parity] != null) {
+ frameContexts[parity].dispose();
+ }
+ final RenderingContext context = new RenderingContext(panelWidth, panelHeight,
+ tilesX, tilesY, viewportCount);
+ context.developerTools = developerTools;
+ context.debugLogBuffer = debugLogBuffer;
+ context.lightingManager = lightingManager;
+ frameContexts[parity] = context;
+ }
+ }
+
+ renderingContext = frameContexts[frameParity];
+ renderingContext.transformExecutor = getOrCreateTransformExecutor();
+ renderingContext.prepareForNewFrameRendering();
+ }
+
+ private boolean notifyFrameListeners(int millisecondsPassedSinceLastUpdate) {
+ boolean reRenderFrame = false;
+ for (final FrameListener listener : frameListeners)
+ if (listener.onFrame(this, millisecondsPassedSinceLastUpdate))
+ reRenderFrame = true;
+ return reRenderFrame;
+ }
+
+ private int getMillisecondsPassedSinceLastUpdate() {
+ final long currentTime = System.currentTimeMillis();
+
+ if (lastUpdateMillis == 0)
+ lastUpdateMillis = currentTime;
+
+ final int millisecondsPassedSinceLastUpdate = (int) (currentTime - lastUpdateMillis);
+ lastUpdateMillis = currentTime;
+ return millisecondsPassedSinceLastUpdate;
+ }
+
+ /**
+ * Removes a previously registered frame listener.
+ *
+ * @param frameListener the listener to remove
+ */
+ public void removeFrameListener(FrameListener frameListener) {
+ frameListeners.remove(frameListener);
+ }
+
+}
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui;
+import eu.svjatoslav.aukio.e3d.renderer.raster.RenderingContext;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.math.TransformStack;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Vertex;
+
+/**
+ * Tracks an object's position in view/camera space for distance and angle calculations.
+ *
+ * <p>Used primarily for level-of-detail (LOD) decisions based on how far and at what
+ * angle the viewer is from an object. The tracker maintains the object's center point
+ * transformed into view space, and optionally orientation axes for angle calculations.</p>
+ *
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape
+ */
+public class ViewSpaceTracker {
+
+ /**
+ * The object's center point (0,0,0 in object space) transformed to view space.
+ */
+ public Vertex center = new Vertex();
+
+ /**
+ * Point at (10,0,0) in object space, used for XZ angle calculation.
+ * Only initialized if orientation tracking is enabled.
+ */
+ public Vertex right;
+
+ /**
+ * Point at (0,10,0) in object space, used for YZ angle calculation.
+ * Only initialized if orientation tracking is enabled.
+ */
+ public Vertex down;
+
+ /**
+ * Creates a new view space tracker.
+ */
+ public ViewSpaceTracker() {
+ }
+
+ /**
+ * Transforms the tracked points from object space to view space.
+ *
+ * @param transformPipe the current transform stack
+ * @param renderingContext the rendering context for frame info
+ */
+ public void analyze(final TransformStack transformPipe,
+ final RenderingContext renderingContext) {
+
+ center.calculateLocationRelativeToViewer(transformPipe, renderingContext);
+
+ if (right != null) {
+ right.calculateLocationRelativeToViewer(transformPipe, renderingContext);
+ down.calculateLocationRelativeToViewer(transformPipe, renderingContext);
+ }
+ }
+
+ /**
+ * Enables tracking of orientation axes for angle calculations.
+ * Disabled by default to save computation when angles are not needed.
+ */
+ public void enableOrientationTracking() {
+ right = new Vertex(new Point3D(10, 0, 0));
+ down = new Vertex(new Point3D(0, 10, 0));
+ }
+
+ /**
+ * Returns the angle between the viewer and object in the XY plane.
+ *
+ * @return the XY angle in radians
+ */
+ public double getAngleXY(final RenderingContext renderingContext) {
+ return center.transformedCoordinate(renderingContext)
+ .getAngleXY(down.transformedCoordinate(renderingContext));
+ }
+
+ /**
+ * Returns the angle between the viewer and object in the XZ plane.
+ *
+ * @return the XZ angle in radians
+ */
+ public double getAngleXZ(final RenderingContext renderingContext) {
+ return center.transformedCoordinate(renderingContext)
+ .getAngleXZ(right.transformedCoordinate(renderingContext));
+ }
+
+ /**
+ * Returns the angle between the viewer and object in the YZ plane.
+ *
+ * @return the YZ angle in radians
+ */
+ public double getAngleYZ(final RenderingContext renderingContext) {
+ return center.transformedCoordinate(renderingContext)
+ .getAngleYZ(down.transformedCoordinate(renderingContext));
+ }
+
+ /**
+ * Returns the distance from the camera to the object's center.
+ * Used for level-of-detail calculations.
+ *
+ * @return the distance in world units
+ */
+ public double getDistanceToCamera(final RenderingContext renderingContext) {
+ return center.transformedCoordinate(renderingContext).getVectorLength();
+ }
+
+}
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui.headtrack;
+
+import eu.svjatoslav.aukio.e3d.gui.FrameListener;
+import eu.svjatoslav.aukio.e3d.gui.ViewPanel;
+import eu.svjatoslav.aukio.e3d.math.Quaternion;
+
+import java.awt.event.KeyEvent;
+
+/**
+ * Applies head orientation from XR glasses to the camera, every frame:
+ * turn your head left and the view pans left, look up and the view
+ * tilts up. The virtual world stays fixed in space while the display
+ * moves with your head.
+ *
+ * <p><b>Complementary mouse look:</b> mouse drag and head tracking
+ * compose instead of fighting. Every frame the controller compares the
+ * camera rotation against what it wrote last frame; a mismatch means
+ * the mouse moved the view, and the difference is folded into the base
+ * yaw/pitch so the view stays exactly where the mouse put it —
+ * subsequent head motion then composes on top. Head movement during a
+ * drag is not lost: it re-applies as a relative delta once the drag
+ * ends.</p>
+ *
+ * <p>Press <b>Scroll Lock</b> to recenter: the current head pose becomes
+ * "straight ahead" and the camera returns to its base pose. Needed
+ * occasionally because gyro-only yaw drifts slowly.</p>
+ *
+ * <p>Arrow-key movement and wheel vertical movement are unaffected
+ * (they translate, not rotate).</p>
+ *
+ * <p>Head roll is measured but deliberately not applied — a constant
+ * world horizon reads better than a world that tilts with your neck.</p>
+ */
+public final class HeadLookController implements FrameListener {
+
+ /**
+ * Sign mapping, confirmed by live user testing: positive engine yaw
+ * turns the view left, so head-yaw is added directly; head-down
+ * integrates to positive pitch while negative engine pitch looks
+ * down, so pitch is subtracted.
+ */
+ private static final double YAW_SIGN = 1.0;
+ private static final double PITCH_SIGN = -1.0;
+
+ /** Yaw sensitivity multiplier; 2.0 = the view turns twice as far as
+ * the head (live-tuned 2026-09-10: head yaw was under-responsive). */
+ private static final double YAW_GAIN = 2.0;
+
+ /** Pitch sensitivity multiplier; 1.0 = the world stays fixed in space. */
+ private static final double PITCH_GAIN = 1.0;
+
+ /**
+ * Two rotations are "the same" below this per-component distance.
+ * A rotation this controller wrote itself compares bitwise identical;
+ * anything past this epsilon came from another writer (mouse drag).
+ */
+ private static final double SAME_ROTATION_EPSILON = 1e-9;
+
+ private final HeadTracker tracker;
+ private final ViewPanel viewPanel;
+
+ private double baseYaw, basePitch;
+
+ /** Rotation this controller wrote to the camera last frame. */
+ private Quaternion lastApplied;
+
+ private boolean recenteredOnce;
+ private boolean scrollLockWasPressed;
+
+ public HeadLookController(final HeadTracker tracker,
+ final ViewPanel viewPanel) {
+ this.tracker = tracker;
+ this.viewPanel = viewPanel;
+ }
+
+ @Override
+ public boolean onFrame(final ViewPanel viewPanel,
+ final int millisecondsSinceLastFrame) {
+ if (!tracker.isCalibrated())
+ return false;
+
+ final boolean scrollLockPressed = viewPanel.getInputManager()
+ .isKeyPressed(KeyEvent.VK_SCROLL_LOCK);
+ if (scrollLockPressed && !scrollLockWasPressed) {
+ captureBasePose();
+ tracker.recenter();
+ recenteredOnce = true;
+ lastApplied = null;
+ }
+ scrollLockWasPressed = scrollLockPressed;
+
+ if (!recenteredOnce) {
+ // Boot recenter: capture the camera pose the application
+ // configured (not the constructor-time identity) and make
+ // the current head pose "straight ahead".
+ captureBasePose();
+ tracker.recenter();
+ recenteredOnce = true;
+ }
+
+ final double lookYaw = tracker.getLookYaw();
+ final double lookPitch = tracker.getLookPitch();
+
+ if (lastApplied != null) {
+ final Quaternion current = viewPanel.getCamera()
+ .getTransform().getRotation();
+ if (!nearlyEqual(current, lastApplied)) {
+ // An external writer (mouse drag) moved the camera.
+ // Re-derive base yaw/pitch so the view stays exactly
+ // where the mouse left it — no snap-back.
+ final double[] angles = current.toAngles();
+ baseYaw = angles[0] - YAW_SIGN * YAW_GAIN * lookYaw;
+ basePitch = angles[1] - PITCH_SIGN * PITCH_GAIN * lookPitch;
+ }
+ }
+
+ final double yaw = baseYaw + YAW_SIGN * YAW_GAIN * lookYaw;
+ final double pitch = basePitch + PITCH_SIGN * PITCH_GAIN * lookPitch;
+ final Quaternion applied = Quaternion.fromAngles(yaw, pitch, 0);
+ viewPanel.getCamera().getTransform().getRotation().set(applied);
+ lastApplied = applied;
+
+ return true;
+ }
+
+ private void captureBasePose() {
+ final double[] angles = viewPanel.getCamera().getTransform()
+ .getRotation().toAngles();
+ baseYaw = angles[0];
+ basePitch = angles[1];
+ }
+
+ private static boolean nearlyEqual(final Quaternion a,
+ final Quaternion b) {
+ return Math.abs(a.w - b.w) < SAME_ROTATION_EPSILON
+ && Math.abs(a.x - b.x) < SAME_ROTATION_EPSILON
+ && Math.abs(a.y - b.y) < SAME_ROTATION_EPSILON
+ && Math.abs(a.z - b.z) < SAME_ROTATION_EPSILON;
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui.headtrack;
+
+import com.sun.jna.Memory;
+
+/**
+ * Head orientation tracker built on the RayNeo glasses IMU.
+ *
+ * <p>A daemon thread reads 500 Hz IMU frames and fuses them into yaw,
+ * pitch and roll angles with a complementary filter: gyroscope
+ * integration for responsiveness, accelerometer gravity as the long-term
+ * pitch/roll reference. Yaw has no absolute reference (the magnetometer
+ * is too noisy indoors near a laptop), so it drifts slowly — call
+ * {@link #recenter()} (Scroll Lock in {@link HeadLookController})
+ * whenever the view feels off-center.</p>
+ *
+ * <p>Sensor axes, established by calibration capture: gyro[0]/X = pitch
+ * (nod), gyro[1]/Y = yaw (left/right turn), gyro[2]/Z = roll
+ * (ear-to-shoulder tilt).</p>
+ *
+ * <p>Drift control ("standstill perceived as slow motion"):</p>
+ * <ul>
+ * <li>Startup calibration only accepts samples taken while the
+ * glasses are stationary — moving samples would poison the bias
+ * estimate with phantom rotation. Putting the glasses on a desk
+ * for the first second gives the cleanest estimate, but a held
+ * head passes the stillness gate too.</li>
+ * <li>While running, the bias is continuously re-estimated whenever
+ * the head is stationary (fast EMA, ~0.5s time constant).</li>
+ * <li>Residual rates below {@value #DEADBAND_DPS} dps after bias
+ * subtraction are integrated as exactly zero — sensor noise can
+ * never accumulate into visible rotation.</li>
+ * </ul>
+ */
+public final class HeadTracker {
+
+ /** Sensor axis indices. */
+ private static final int AXIS_PITCH = 0;
+ private static final int AXIS_YAW = 1;
+ private static final int AXIS_ROLL = 2;
+
+ private static final double DPS_TO_RAD = Math.PI / 180.0;
+
+ /** Stationary samples needed for the initial bias estimate. */
+ private static final int CALIBRATION_SAMPLES = 500;
+
+ /** Give up waiting for stillness after this long and calibrate anyway. */
+ private static final int CALIBRATION_TIMEOUT_SAMPLES = 5000;
+
+ /** Gyro magnitude below which the head counts as stationary (dps). */
+ private static final double STATIONARY_THRESHOLD_DPS = 0.5;
+
+ /**
+ * Rates below this after bias subtraction are treated as zero.
+ * Kills the slow phantom rotation that gyro noise would otherwise
+ * integrate into.
+ */
+ private static final double DEADBAND_DPS = 0.07;
+
+ /** Complementary filter weight: accel correction per sample. */
+ private static final double ACCEL_BLEND = 0.02;
+
+ /** Bias re-estimation speed while stationary (~0.5s time constant). */
+ private static final double BIAS_BLEND = 0.004;
+
+ /** Output smoothing (exponential moving average per sample). */
+ private static final double OUTPUT_SMOOTHING = 0.35;
+
+ private final RayNeoHid device;
+ private final Thread readerThread;
+ private final Memory frame = new Memory(RayNeoHid.FRAME_SIZE);
+
+ private final double[] gyroBias = new double[3];
+ private int calibrationSamples;
+ private int calibrationAttempts;
+
+ private double fusedYaw, fusedPitch, fusedRoll;
+ private double centerYaw, centerPitch;
+ private double smoothYaw, smoothPitch;
+ private int lastTick;
+ private long lastSampleNanos;
+ private boolean hasTick;
+
+ private volatile boolean running = true;
+ private volatile boolean calibrated;
+
+ // diagnostics (all written on the reader thread, read anywhere)
+ private volatile int framesReceived;
+ private volatile int lastTickValue;
+ private volatile double lastDtMillis;
+ private volatile double maxAbsGyroDps;
+
+ public HeadTracker(final RayNeoHid device) {
+ this.device = device;
+ readerThread = new Thread(this::readLoop, "rayneo-head-tracker");
+ readerThread.setDaemon(true);
+ }
+
+ public void start() {
+ device.startImu();
+ readerThread.start();
+ final Thread watchdog = new Thread(this::watchdogLoop,
+ "rayneo-imu-watchdog");
+ watchdog.setDaemon(true);
+ watchdog.start();
+ }
+
+ /**
+ * The glasses occasionally answer IMU-ON with a stream of frozen
+ * frames (tick not advancing). If frames stall or the tick freezes,
+ * re-send the enable sequence.
+ */
+ private void watchdogLoop() {
+ int lastFrames = 0;
+ int lastTickSeen = 0;
+ while (running) {
+ try {
+ Thread.sleep(2000);
+ } catch (final InterruptedException e) {
+ Thread.currentThread().interrupt();
+ return;
+ }
+ final int frames = framesReceived;
+ final int tick = lastTickValue;
+ if (frames > 10 && frames == lastFrames) {
+ System.err.println("head tracker: frame stream stalled, "
+ + "re-enabling IMU");
+ device.startImu();
+ } else if (frames > 1000 && tick == lastTickSeen) {
+ System.err.println("head tracker: tick frozen (stale "
+ + "sensor data), re-enabling IMU");
+ device.startImu();
+ }
+ lastFrames = frames;
+ lastTickSeen = tick;
+ }
+ }
+
+ /**
+ * One-line diagnostic snapshot: frame flow, tick, integration health.
+ */
+ public String getDebugString() {
+ return String.format(
+ "frames=%d tick=%d dt=%.2fms maxGyro=%.1fdps "
+ + "calibrated=%b yaw=%.2fdeg pitch=%.2fdeg",
+ framesReceived, lastTickValue, lastDtMillis,
+ maxAbsGyroDps, calibrated, Math.toDegrees(getLookYaw()),
+ Math.toDegrees(getLookPitch()));
+ }
+
+ /**
+ * Makes the current head orientation the new "straight ahead".
+ */
+ public synchronized void recenter() {
+ centerYaw = fusedYaw;
+ centerPitch = fusedPitch;
+ smoothYaw = 0;
+ smoothPitch = 0;
+ }
+
+ /** Head yaw relative to the last recenter, radians. */
+ public synchronized double getLookYaw() {
+ return smoothYaw;
+ }
+
+ /** Head pitch relative to the last recenter, radians. */
+ public synchronized double getLookPitch() {
+ return smoothPitch;
+ }
+
+ /** False until the initial gyro bias calibration has finished. */
+ public boolean isCalibrated() {
+ return calibrated;
+ }
+
+ /** True while the reader thread is alive and frames may be flowing. */
+ public boolean isRunning() {
+ return running && readerThread.isAlive();
+ }
+
+ public void stop() {
+ running = false;
+ // Close first: the reader thread is parked in a native read that no
+ // interrupt can wake; closing the fd fails the read instantly.
+ device.close();
+ try {
+ readerThread.join(500);
+ } catch (final InterruptedException e) {
+ Thread.currentThread().interrupt();
+ }
+ }
+
+ private void readLoop() {
+ while (running) {
+ final int type = device.readFrame(frame);
+ if (type < 0) {
+ if (running)
+ System.err.println("head tracker: device read failed "
+ + "(unplugged?), stopping");
+ running = false;
+ return;
+ }
+ if (type == RayNeoHid.TYPE_IMU)
+ onSample();
+ }
+ running = false;
+ }
+
+ private void onSample() {
+ final float gx = frame.getFloat(16);
+ final float gy = frame.getFloat(20);
+ final float gz = frame.getFloat(24);
+ final float ax = frame.getFloat(4);
+ final float ay = frame.getFloat(8);
+ final float az = frame.getFloat(12);
+ final int tick = frame.getInt(40);
+
+ framesReceived++;
+ lastTickValue = tick;
+ final double absGyro = Math.sqrt(gx * gx + gy * gy + gz * gz);
+ if (absGyro > maxAbsGyroDps)
+ maxAbsGyroDps = absGyro;
+
+ if (!calibrated) {
+ calibrate(gx, gy, gz, ax, ay, az, tick, absGyro);
+ return;
+ }
+
+ final double dt;
+ if (hasTick) {
+ // The device tick is NOT microseconds (measured: ~50µs per
+ // unit) — useless for integration timing, kept only as a
+ // liveness signal for the watchdog. Wall clock at 500Hz is
+ // fine; jitter is smoothed by the output EMA.
+ dt = Math.min(Math.max((System.nanoTime() - lastSampleNanos)
+ / 1_000_000_000.0, 0), 0.1);
+ } else {
+ dt = 0.002;
+ }
+ lastDtMillis = dt * 1000;
+ lastSampleNanos = System.nanoTime();
+ lastTick = tick;
+ hasTick = true;
+
+ if (absGyro < STATIONARY_THRESHOLD_DPS)
+ for (int i = 0; i < 3; i++) {
+ final double g = i == AXIS_PITCH ? gx : i == AXIS_YAW ? gy : gz;
+ gyroBias[i] += (g - gyroBias[i]) * BIAS_BLEND;
+ }
+
+ synchronized (this) {
+ fusedPitch += deadband(gx - gyroBias[AXIS_PITCH]) * DPS_TO_RAD * dt;
+ fusedYaw += deadband(gy - gyroBias[AXIS_YAW]) * DPS_TO_RAD * dt;
+ fusedRoll += deadband(gz - gyroBias[AXIS_ROLL]) * DPS_TO_RAD * dt;
+
+ // gravity reference: pitch rotates around sensor X (mixes the
+ // Y/Z gravity components), roll around sensor Z (mixes X/Y)
+ final double accelPitch = Math.atan2(az, ay);
+ final double accelRoll = Math.atan2(-ax, ay);
+ fusedPitch += (accelPitch - fusedPitch) * ACCEL_BLEND;
+ fusedRoll += (accelRoll - fusedRoll) * ACCEL_BLEND;
+
+ final double yaw = fusedYaw - centerYaw;
+ final double pitch = fusedPitch - centerPitch;
+ smoothYaw += (yaw - smoothYaw) * OUTPUT_SMOOTHING;
+ smoothPitch += (pitch - smoothPitch) * OUTPUT_SMOOTHING;
+ }
+ }
+
+ /**
+ * Gyro bias calibration: only stationary samples contribute — if
+ * the user is already turning, those samples would poison the bias
+ * with several dps of phantom drift. Give up after ~10s and accept
+ * whatever we have.
+ */
+ private void calibrate(final float gx, final float gy, final float gz,
+ final float ax, final float ay, final float az,
+ final int tick, final double absGyro) {
+ calibrationAttempts++;
+ if (absGyro < STATIONARY_THRESHOLD_DPS
+ || calibrationAttempts > CALIBRATION_TIMEOUT_SAMPLES) {
+ gyroBias[AXIS_PITCH] += gx;
+ gyroBias[AXIS_YAW] += gy;
+ gyroBias[AXIS_ROLL] += gz;
+ calibrationSamples++;
+ }
+ if (calibrationSamples >= CALIBRATION_SAMPLES) {
+ for (int i = 0; i < 3; i++)
+ gyroBias[i] /= calibrationSamples;
+ // jump-start the tilt estimate from gravity; otherwise the
+ // filter would take a second to converge and the boot
+ // recenter would capture the unconverged zero
+ fusedPitch = Math.atan2(az, ay);
+ fusedRoll = Math.atan2(-ax, ay);
+ calibrated = true;
+ lastTick = tick;
+ lastSampleNanos = System.nanoTime();
+ hasTick = true;
+ }
+ }
+
+ private static double deadband(final double rateDps) {
+ return Math.abs(rateDps) < DEADBAND_DPS ? 0 : rateDps;
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui.headtrack;
+
+import eu.svjatoslav.aukio.e3d.gui.ViewPanel;
+
+/**
+ * Hot-plug manager for XR glasses head tracking. Polls for RayNeo
+ * glasses every two seconds:
+ *
+ * <ul>
+ * <li>glasses plugged in → open the HID pipe, start a
+ * {@link HeadTracker}, attach a {@link HeadLookController} to the
+ * view's frame listeners</li>
+ * <li>glasses unplugged (tracker read fails) → stop the tracker and
+ * detach the controller, so the camera is no longer driven by a
+ * dead device</li>
+ * <li>plugged back in → fresh tracker, fresh boot recenter</li>
+ * </ul>
+ *
+ * <p>Permission failures are reported once, then retried silently —
+ * the user may install the udev rule while the application is running.</p>
+ */
+public final class HeadTrackingManager {
+
+ private static final long POLL_INTERVAL_MS = 2000;
+
+ private final ViewPanel viewPanel;
+ private final Thread thread;
+
+ private volatile boolean running = true;
+ private HeadTracker tracker;
+ private HeadLookController controller;
+ private boolean failureReported;
+
+ public HeadTrackingManager(final ViewPanel viewPanel) {
+ this.viewPanel = viewPanel;
+ thread = new Thread(this::pollLoop, "head-tracking-hotplug");
+ thread.setDaemon(true);
+ }
+
+ public void start() {
+ thread.start();
+ }
+
+ /** Active tracker, or null when no glasses are connected. */
+ public HeadTracker getTracker() {
+ return tracker;
+ }
+
+ public void stop() {
+ running = false;
+ // Wake the 2 s poll sleep; without the interrupt the join below
+ // burns its full 1 s timeout on the EDT at every window close.
+ thread.interrupt();
+ try {
+ thread.join(1000);
+ } catch (final InterruptedException e) {
+ Thread.currentThread().interrupt();
+ }
+ disconnect();
+ }
+
+ private void pollLoop() {
+ while (running) {
+ poll();
+ try {
+ Thread.sleep(POLL_INTERVAL_MS);
+ } catch (final InterruptedException e) {
+ Thread.currentThread().interrupt();
+ return;
+ }
+ }
+ }
+
+ private void poll() {
+ if (tracker != null && !tracker.isRunning()) {
+ System.out.println("head tracking: glasses disconnected");
+ disconnect();
+ }
+ if (tracker != null)
+ return;
+
+ try {
+ final RayNeoHid glasses = RayNeoHid.open();
+ if (glasses == null)
+ return;
+ tracker = new HeadTracker(glasses);
+ tracker.start();
+ controller = new HeadLookController(tracker, viewPanel);
+ viewPanel.addFrameListener(controller);
+ failureReported = false;
+ System.out.println("head tracking: RayNeo glasses detected, "
+ + "calibrating (hold still for a second)");
+ } catch (final Exception e) {
+ tracker = null;
+ if (!failureReported) {
+ failureReported = true;
+ System.err.println("head tracking unavailable: "
+ + e.getMessage());
+ }
+ }
+ }
+
+ private void disconnect() {
+ if (controller != null) {
+ viewPanel.removeFrameListener(controller);
+ controller = null;
+ }
+ if (tracker != null) {
+ tracker.stop();
+ tracker = null;
+ }
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui.headtrack;
+
+import com.sun.jna.Library;
+import com.sun.jna.Memory;
+import com.sun.jna.Native;
+
+import java.io.IOException;
+import java.nio.file.DirectoryStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+/**
+ * Raw HID transport for RayNeo AR glasses (T&A Mobile Phones,
+ * VID 1BBB, PID AF50) via Linux hidraw.
+ *
+ * <p>IMU sample layout inside a 0x65 frame (all little-endian):</p>
+ * <ul>
+ * <li>float acc[3] at offset 4 (m/s²)</li>
+ * <li>float gyro[3] at offset 16 (degrees/second)</li>
+ * <li>float temperature at 28, float magnet[0..1] at 32</li>
+ * <li>uint32 tick at 40 (NOT microseconds — ~50µs per unit; use only
+ * as a liveness signal, never for integration timing)</li>
+ * <li>float psensor at 44, float lsensor at 48, float magnet[2] at 52</li>
+ * </ul>
+ *
+ * <p>Startup sequence that yields live data: psensor enable (0x38) THEN
+ * IMU on (0x01). Without the psensor enable the glasses may stream
+ * frozen sensor values.</p>
+ *
+ * <p>Permissions: /dev/hidraw* is root-only by default. Install a udev
+ * rule (e.g. {@code 99-rayneo-glasses.rules} with MODE="0666" for
+ * VID 1BBB PID AF50) to allow user access.</p>
+ */
+public final class RayNeoHid implements AutoCloseable {
+
+ public static final int FRAME_SIZE = 64;
+
+ private static final int O_RDWR = 0x02;
+ private static final byte MAGIC_OUT = 0x66;
+ private static final byte MAGIC_IN = (byte) 0x99;
+
+ /** Frame type: IMU sample. */
+ public static final int TYPE_IMU = 0x65;
+
+ private static final int CMD_DEVICE_INFO = 0x00;
+ private static final int CMD_IMU_ON = 0x01;
+ private static final int CMD_IMU_OFF = 0x02;
+ private static final int CMD_PSENSOR_ENABLE = 0x38;
+
+ private interface CLib extends Library {
+ CLib INSTANCE = Native.load("c", CLib.class);
+
+ int open(String path, int flags);
+
+ int close(int fd);
+
+ int read(int fd, Memory buffer, int count);
+
+ int write(int fd, Memory buffer, int count);
+ }
+
+ private final int fd;
+ private final Memory frameBuffer = new Memory(FRAME_SIZE);
+
+ private RayNeoHid(final int fd) {
+ this.fd = fd;
+ }
+
+ /**
+ * Finds the hidraw node of the glasses by scanning sysfs uevent data,
+ * then opens it. Returns null when the glasses are not connected.
+ */
+ public static RayNeoHid open() throws IOException {
+ final Path hidrawDir = Path.of("/sys/class/hidraw");
+ if (!Files.isDirectory(hidrawDir))
+ return null;
+
+ try (DirectoryStream<Path> nodes = Files.newDirectoryStream(hidrawDir)) {
+ for (final Path node : nodes) {
+ final Path uevent = node.resolve("device/uevent");
+ if (!Files.isRegularFile(uevent))
+ continue;
+ final String content = Files.readString(uevent);
+ if (content.contains("00001BBB") && content.contains("0000AF50")) {
+ final Path dev = Path.of("/dev", node.getFileName().toString());
+ final int fd = CLib.INSTANCE.open(dev.toString(), O_RDWR);
+ if (fd < 0)
+ throw new IOException("cannot open " + dev
+ + " (permissions? install udev rule "
+ + "99-rayneo-glasses.rules)");
+ return new RayNeoHid(fd);
+ }
+ }
+ }
+ return null;
+ }
+
+ /**
+ * Enables the proximity sensor pipeline and starts IMU streaming.
+ * Both commands are required; psensor-first ordering matters.
+ */
+ public void startImu() {
+ sendCommand(CMD_PSENSOR_ENABLE, 0);
+ sendCommand(CMD_IMU_ON, 0);
+ }
+
+ /**
+ * Stops IMU streaming.
+ */
+ public void stopImu() {
+ sendCommand(CMD_IMU_OFF, 0);
+ }
+
+ private void sendCommand(final int command, final int value) {
+ synchronized (frameBuffer) {
+ frameBuffer.clear();
+ frameBuffer.setByte(0, MAGIC_OUT);
+ frameBuffer.setByte(1, (byte) command);
+ frameBuffer.setByte(2, (byte) value);
+ CLib.INSTANCE.write(fd, frameBuffer, FRAME_SIZE);
+ }
+ }
+
+ /**
+ * Blocking read of one 64-byte frame. Returns the frame type byte
+ * (e.g. {@link #TYPE_IMU}) or -1 on error/closed device. The frame
+ * bytes are left in the given buffer for the caller to parse.
+ */
+ public int readFrame(final Memory out) {
+ final int n = CLib.INSTANCE.read(fd, out, FRAME_SIZE);
+ if (n != FRAME_SIZE || out.getByte(0) != MAGIC_IN)
+ return -1;
+ return out.getByte(1) & 0xFF;
+ }
+
+ @Override
+ public void close() {
+ try {
+ stopImu();
+ } catch (final Exception ignored) {
+ // device may already be unplugged
+ }
+ CLib.INSTANCE.close(fd);
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui.humaninput;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point2D;
+import eu.svjatoslav.aukio.e3d.geometry.Camera;
+import eu.svjatoslav.aukio.e3d.gui.FrameListener;
+import eu.svjatoslav.aukio.e3d.gui.ViewFrame;
+import eu.svjatoslav.aukio.e3d.gui.ViewPanel;
+import eu.svjatoslav.aukio.e3d.math.Quaternion;
+
+import java.awt.*;
+import java.awt.event.*;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Manages mouse and keyboard input for the 3D view.
+ *
+ * <p>Handles mouse/keyboard events, tracks pressed keys and mouse state,
+ * and forwards events to the appropriate handlers. Also provides default camera
+ * control via mouse dragging (look around) and mouse wheel (vertical movement).</p>
+ *
+ * @see ViewPanel#getInputManager()
+ */
+public class InputManager implements
+ MouseMotionListener, KeyListener, MouseListener, MouseWheelListener, FrameListener {
+
+ private final Map<Integer, Long> pressedKeysToPressedTimeMap = new HashMap<>();
+ private final List<MouseEvent> detectedMouseEvents = new ArrayList<>();
+ private final List<KeyEvent> detectedKeyEvents = new ArrayList<>();
+ private final Point2D mouseDelta = new Point2D();
+ private final MouseEvent reusableHoverEvent = new MouseEvent(new Point2D(), 0);
+ private final Point2D reusableMouseLocation = new Point2D();
+ private final ViewPanel viewPanel;
+ private int wheelVerticalUnits = 0;
+ private int wheelHorizontalUnits = 0;
+ private Point2D oldMouseCoordinatesWhenDragging;
+ private Point2D currentMouseLocation;
+ private boolean mouseMoved;
+ private boolean mouseWithinWindow = false;
+ private double cameraYaw = 0;
+ private double cameraPitch = 0;
+ private double cameraRoll = 0;
+
+ /**
+ * Creates an input manager attached to the given view panel.
+ *
+ * @param viewPanel the view panel to receive input from
+ */
+ public InputManager(final ViewPanel viewPanel) {
+ this.viewPanel = viewPanel;
+ bind(viewPanel);
+ }
+
+ /**
+ * Processes accumulated input events and updates camera based on mouse drag/wheel.
+ *
+ * @param viewPanel the view panel
+ * @param millisecondsSinceLastFrame time since last frame (unused)
+ * @return {@code true} if a view repaint is needed
+ */
+ @Override
+ public boolean onFrame(final ViewPanel viewPanel, final int millisecondsSinceLastFrame) {
+ boolean viewUpdateNeeded = handleKeyboardEvents();
+ viewUpdateNeeded |= handleMouseClicksAndHover(viewPanel);
+ viewUpdateNeeded |= handleMouseDragging();
+ viewUpdateNeeded |= handleMouseScrolling();
+ return viewUpdateNeeded;
+ }
+
+ /**
+ * Binds this input manager to listen for events on the given component.
+ * Also registers a global {@link KeyEventDispatcher} so keyboard shortcuts
+ * (F11, F12, SHIFT+F11) work even when the ViewPanel does not have focus.
+ *
+ * @param component the component to attach listeners to
+ */
+ private void bind(final Component component) {
+ component.addMouseMotionListener(this);
+ component.addKeyListener(this);
+ component.addMouseListener(this);
+ component.addMouseWheelListener(this);
+ }
+
+ /**
+ * Processes all accumulated keyboard events and forwards them to the current focus owner.
+ *
+ * @return {@code true} if any event handler requested a repaint
+ */
+ private boolean handleKeyboardEvents() {
+ final KeyboardInputHandler currentFocusOwner = viewPanel.getKeyboardFocusStack().getCurrentFocusOwner();
+
+ if (currentFocusOwner == null)
+ return false;
+
+ boolean viewUpdateNeeded = false;
+ synchronized (detectedKeyEvents) {
+ for (int i = 0; i < detectedKeyEvents.size(); i++)
+ viewUpdateNeeded |= processKeyEvent(currentFocusOwner, detectedKeyEvents.get(i));
+ detectedKeyEvents.clear();
+ }
+ return viewUpdateNeeded;
+ }
+
+ /**
+ * Processes a single keyboard event by dispatching to the focus owner.
+ *
+ * @param currentFocusOwner the component that currently has keyboard focus
+ * @param keyEvent the keyboard event to process
+ * @return {@code true} if the handler requested a repaint
+ */
+ private boolean processKeyEvent(KeyboardInputHandler currentFocusOwner, KeyEvent keyEvent) {
+ switch (keyEvent.getID()) {
+ case KeyEvent.KEY_PRESSED:
+ return currentFocusOwner.keyPressed(keyEvent, viewPanel);
+
+ case KeyEvent.KEY_RELEASED:
+ return currentFocusOwner.keyReleased(keyEvent, viewPanel);
+ }
+ return false;
+ }
+
+ /**
+ * Handles mouse clicks and hover detection.
+ * Sets up the mouse event in the rendering context for shape hit testing.
+ *
+ * @param viewPanel the view panel
+ * @return {@code true} if a repaint is needed
+ */
+ private synchronized boolean handleMouseClicksAndHover(final ViewPanel viewPanel) {
+ boolean rerenderNeeded = false;
+ MouseEvent event = findClickLocationToTrace();
+ if (event != null) {
+ rerenderNeeded = true;
+ } else {
+ if (mouseMoved) {
+ mouseMoved = false;
+ rerenderNeeded = true;
+ }
+
+ if (currentMouseLocation != null) {
+ reusableHoverEvent.coordinate.x = currentMouseLocation.x;
+ reusableHoverEvent.coordinate.y = currentMouseLocation.y;
+ event = reusableHoverEvent;
+ }
+ }
+
+ if (viewPanel.getRenderingContext() != null)
+ viewPanel.getRenderingContext().setMouseEvent(event);
+
+ return rerenderNeeded;
+ }
+
+ private MouseEvent findClickLocationToTrace() {
+ synchronized (detectedMouseEvents) {
+ if (detectedMouseEvents.isEmpty())
+ return null;
+
+ return detectedMouseEvents.remove(0);
+ }
+ }
+
+ /**
+ * Returns whether the specified key is currently pressed.
+ *
+ * @param keyCode the key code (from {@link java.awt.event.KeyEvent})
+ * @return {@code true} if the key is currently pressed
+ */
+ public boolean isKeyPressed(final int keyCode) {
+ return pressedKeysToPressedTimeMap.containsKey(keyCode);
+ }
+
+ @Override
+ public void keyPressed(final KeyEvent evt) {
+ if (evt.getKeyCode() == java.awt.event.KeyEvent.VK_F12) {
+ viewPanel.showDeveloperToolsPanel();
+ return;
+ }
+ if (evt.getKeyCode() == java.awt.event.KeyEvent.VK_F11) {
+ final ViewFrame frame = findParentViewFrame();
+ if (frame != null) {
+ if (evt.isShiftDown()) {
+ // SHIFT+F11: toggle stereo + fullscreen together
+ final boolean stereoOn = !viewPanel.isStereoModeEnabled();
+ viewPanel.setStereoModeEnabled(stereoOn);
+ frame.setFullscreen(stereoOn);
+ } else {
+ // F11: toggle fullscreen only
+ frame.toggleFullscreen();
+ }
+ }
+ return;
+ }
+ // +/- adjusts stereo IPD (inter-pupillary distance) when stereo is active
+ if (viewPanel.isStereoModeEnabled()) {
+ final int code = evt.getKeyCode();
+ if (code == java.awt.event.KeyEvent.VK_PLUS
+ || code == java.awt.event.KeyEvent.VK_EQUALS
+ || code == java.awt.event.KeyEvent.VK_ADD) {
+ viewPanel.setStereoIPD(viewPanel.getStereoIPD() + 0.5);
+ return;
+ }
+ if (code == java.awt.event.KeyEvent.VK_MINUS
+ || code == java.awt.event.KeyEvent.VK_SUBTRACT) {
+ viewPanel.setStereoIPD(Math.max(0.5, viewPanel.getStereoIPD() - 0.5));
+ return;
+ }
+ }
+ synchronized (detectedKeyEvents) {
+ pressedKeysToPressedTimeMap.put(evt.getKeyCode(), System.currentTimeMillis());
+ detectedKeyEvents.add(evt);
+ }
+ }
+
+ @Override
+ public void keyReleased(final KeyEvent evt) {
+ synchronized (detectedKeyEvents) {
+ pressedKeysToPressedTimeMap.remove(evt.getKeyCode());
+ detectedKeyEvents.add(evt);
+ }
+ }
+
+ @Override
+ public void keyTyped(final KeyEvent e) {
+ }
+
+ @Override
+ public void mouseClicked(final java.awt.event.MouseEvent e) {
+ synchronized (detectedMouseEvents) {
+ detectedMouseEvents.add(new MouseEvent(e.getX(), e.getY(), e.getButton()));
+ }
+ }
+
+ @Override
+ public void mouseDragged(final java.awt.event.MouseEvent evt) {
+ reusableMouseLocation.x = evt.getX();
+ reusableMouseLocation.y = evt.getY();
+
+ if (oldMouseCoordinatesWhenDragging == null) {
+ oldMouseCoordinatesWhenDragging = new Point2D(reusableMouseLocation.x, reusableMouseLocation.y);
+ return;
+ }
+
+ mouseDelta.x += reusableMouseLocation.x - oldMouseCoordinatesWhenDragging.x;
+ mouseDelta.y += reusableMouseLocation.y - oldMouseCoordinatesWhenDragging.y;
+
+ oldMouseCoordinatesWhenDragging.x = reusableMouseLocation.x;
+ oldMouseCoordinatesWhenDragging.y = reusableMouseLocation.y;
+ }
+
+ @Override
+ public void mouseEntered(final java.awt.event.MouseEvent e) {
+ mouseWithinWindow = true;
+ }
+
+ @Override
+ public synchronized void mouseExited(final java.awt.event.MouseEvent e) {
+ mouseWithinWindow = false;
+ currentMouseLocation = null;
+ }
+
+ @Override
+ public synchronized void mouseMoved(final java.awt.event.MouseEvent e) {
+ if (currentMouseLocation == null)
+ currentMouseLocation = new Point2D(e.getX(), e.getY());
+ else {
+ currentMouseLocation.x = e.getX();
+ currentMouseLocation.y = e.getY();
+ }
+ mouseMoved = true;
+ }
+
+ @Override
+ public void mousePressed(final java.awt.event.MouseEvent e) {
+ // Extra buttons (mouse back/forward) never produce an AWT CLICKED
+ // event on Linux (only PRESSED/RELEASED), so they are delivered
+ // to the component already on press.
+ if (e.getButton() > 3) {
+ synchronized (detectedMouseEvents) {
+ detectedMouseEvents.add(
+ new MouseEvent(e.getX(), e.getY(), e.getButton()));
+ }
+ }
+ // Initialize camera rotation state from current camera orientation.
+ // This prevents a jump when the camera was programmatically positioned
+ // with a non-default rotation before the user started dragging.
+ final Camera camera = viewPanel.getCamera();
+ final double[] angles = camera.getTransform().getRotation().toAngles();
+ cameraYaw = angles[0];
+ cameraPitch = angles[1];
+ cameraRoll = angles[2];
+ }
+
+ @Override
+ public void mouseReleased(final java.awt.event.MouseEvent evt) {
+ oldMouseCoordinatesWhenDragging = null;
+ }
+
+ @Override
+ public void mouseWheelMoved(final java.awt.event.MouseWheelEvent evt) {
+ // horizontal wheel input arrives as shift-modified vertical
+ // rotation (AWT convention on all platforms)
+ if (evt.isShiftDown())
+ wheelHorizontalUnits += evt.getWheelRotation();
+ else
+ wheelVerticalUnits += evt.getWheelRotation();
+ }
+
+ /**
+ * Routes scroll wheel input: to the focused GUI component when it
+ * consumes it, otherwise to the camera (vertical = up/down,
+ * horizontal = strafe left/right).
+ */
+ private boolean handleMouseScrolling() {
+ final int vertical = wheelVerticalUnits;
+ final int horizontal = wheelHorizontalUnits;
+ wheelVerticalUnits = 0;
+ wheelHorizontalUnits = 0;
+ if (vertical == 0 && horizontal == 0)
+ return false;
+
+ final KeyboardInputHandler focusOwner = viewPanel
+ .getKeyboardFocusStack().getCurrentFocusOwner();
+ if (focusOwner instanceof MouseInteractionController component
+ && component.mouseWheelMoved(vertical, horizontal))
+ // consumed by the focused component
+ return true;
+
+ final Camera camera = viewPanel.getCamera();
+ final double actualAcceleration = 50 * camera.cameraAcceleration * (1 + (camera.getMovementSpeed() / 10));
+ camera.getMovementVector().y += (vertical * actualAcceleration);
+ camera.getMovementVector().x += (horizontal * actualAcceleration);
+ camera.enforceSpeedLimit();
+ return true;
+ }
+
+ private boolean handleMouseDragging() {
+ if (mouseDelta.isZero()) {
+ return false;
+ }
+
+ cameraYaw -= mouseDelta.x / 50.0;
+ cameraPitch -= mouseDelta.y / 50.0;
+
+ cameraPitch = Math.max(-Math.PI / 2 + 0.001,
+ Math.min( Math.PI / 2 - 0.001, cameraPitch));
+
+ final Camera camera = viewPanel.getCamera();
+ camera.getTransform().getRotation().set(
+ Quaternion.fromAngles(cameraYaw, cameraPitch, cameraRoll));
+
+ mouseDelta.zero();
+ return true;
+ }
+
+ /**
+ * Walks up the component hierarchy from the view panel to find the
+ * parent {@link ViewFrame}, if any.
+ *
+ * @return the parent ViewFrame, or {@code null} if the ViewPanel is
+ * not embedded in a ViewFrame
+ */
+ private ViewFrame findParentViewFrame() {
+ java.awt.Container parent = viewPanel.getParent();
+ while (parent != null) {
+ if (parent instanceof ViewFrame)
+ return (ViewFrame) parent;
+ parent = parent.getParent();
+ }
+ return null;
+ }
+
+}
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui.humaninput;
+import eu.svjatoslav.aukio.e3d.geometry.Camera;
+
+import eu.svjatoslav.aukio.e3d.gui.ViewPanel;
+
+/**
+ * Manages keyboard focus for interactive 3D components.
+ *
+ * <p>Exactly one {@link KeyboardInputHandler} has keyboard focus at a time.
+ * When a component gains focus (e.g., by being clicked), the previous focus
+ * owner is notified and forgotten. When the component releases focus (ESC or
+ * middle mouse button), focus falls back to the default handler — never to a
+ * previously focused component (there is no focus stack).</p>
+ *
+ * <p>The default handler is a {@link WorldNavigationUserInputTracker}, which
+ * handles WASD/arrow-key camera movement while no component has focus.</p>
+ *
+ * <p><b>Focus flow example:</b></p>
+ * <pre>{@code
+ * // Initial state: WorldNavigationUserInputTracker has focus (camera movement)
+ * // User clicks on a text editor:
+ * focus.pushFocusOwner(textEditor);
+ * // Now textEditor receives keyboard events
+ *
+ * // User presses ESC or middle-clicks the editor:
+ * focus.popFocusOwner();
+ * // Camera movement is active again
+ * }</pre>
+ *
+ * @see KeyboardInputHandler the interface that focus owners must implement
+ * @see WorldNavigationUserInputTracker default handler for camera navigation
+ */
+public class KeyboardFocusStack {
+
+ private final ViewPanel viewPanel;
+ private final WorldNavigationUserInputTracker defaultInputHandler = new WorldNavigationUserInputTracker();
+ private KeyboardInputHandler currentUserInputHandler;
+
+ /**
+ * Creates a new focus manager for the given view panel, with
+ * {@link WorldNavigationUserInputTracker} as the default focus owner.
+ *
+ * @param viewPanel the view panel this focus manager belongs to
+ */
+ public KeyboardFocusStack(final ViewPanel viewPanel) {
+ this.viewPanel = viewPanel;
+ currentUserInputHandler = defaultInputHandler;
+ currentUserInputHandler.focusReceived(viewPanel);
+ }
+
+ /**
+ * Returns the handler that currently has keyboard focus. When no
+ * component is focused, this is the default camera navigation handler.
+ *
+ * @return the current focus owner
+ */
+ public KeyboardInputHandler getCurrentFocusOwner() {
+ return currentUserInputHandler;
+ }
+
+ /**
+ * Releases focus from the current focus owner; focus falls back to the
+ * default camera navigation handler. No previously focused component is
+ * restored — focus is single-level, not a stack.
+ */
+ public void popFocusOwner() {
+ if (currentUserInputHandler == defaultInputHandler)
+ return;
+
+ currentUserInputHandler.focusLost(viewPanel);
+ currentUserInputHandler = defaultInputHandler;
+ currentUserInputHandler.focusReceived(viewPanel);
+ }
+
+ /**
+ * Gives keyboard focus to the given handler. The previous focus owner is
+ * notified via {@link KeyboardInputHandler#focusLost} and forgotten.
+ *
+ * <p>If the given handler is already the current focus owner, this method
+ * does nothing and returns {@code false}.</p>
+ *
+ * @param newInputHandler the handler to receive keyboard focus
+ * @return {@code true} if the view needs to be repainted as a result
+ */
+ public boolean pushFocusOwner(final KeyboardInputHandler newInputHandler) {
+ boolean updateNeeded = false;
+
+ if (currentUserInputHandler == newInputHandler)
+ return false;
+
+ if (currentUserInputHandler != null)
+ updateNeeded = currentUserInputHandler.focusLost(viewPanel);
+
+ currentUserInputHandler = newInputHandler;
+ updateNeeded |= currentUserInputHandler.focusReceived(viewPanel);
+
+ return updateNeeded;
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui.humaninput;
+
+import java.awt.event.InputEvent;
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * Utility class providing keyboard key code constants and modifier detection methods.
+ *
+ * <p>Provides named constants for common key codes and static helper methods
+ * to check whether modifier keys (Ctrl, Alt, Shift) are pressed in a given
+ * event modifier mask.</p>
+ *
+ * <p><b>Usage example:</b></p>
+ * <pre>{@code
+ * public boolean keyPressed(KeyEvent event, ViewPanel viewPanel) {
+ * if (event.getKeyCode() == KeyboardHelper.ENTER) {
+ * // Handle Enter key
+ * }
+ * if (KeyboardHelper.isCtrlPressed(event.getModifiersEx())) {
+ * // Handle Ctrl+key combination
+ * }
+ * return true;
+ * }
+ * }</pre>
+ *
+ * @see KeyboardInputHandler the interface for receiving keyboard events
+ */
+public class KeyboardHelper {
+
+ /**
+ * Private constructor to prevent instantiation of this utility class.
+ */
+ private KeyboardHelper() {
+ }
+
+ /** Key code for the Tab key. */
+ public static final int TAB = 9;
+ /** Key code for the Down arrow key. */
+ public static final int DOWN = 40;
+ /** Key code for the Up arrow key. */
+ public static final int UP = 38;
+ /** Key code for the Right arrow key. */
+ public static final int RIGHT = 39;
+ /** Key code for the Left arrow key. */
+ public static final int LEFT = 37;
+ /** Key code for the Page Down key. */
+ public static final int PGDOWN = 34;
+ /** Key code for the Page Up key. */
+ public static final int PGUP = 33;
+ /** Key code for the Home key. */
+ public static final int HOME = 36;
+ /** Key code for the End key. */
+ public static final int END = 35;
+ /** Key code for the Delete key. */
+ public static final int DEL = 127;
+ /** Key code for the Enter/Return key. */
+ public static final int ENTER = 10;
+ /** Key code for the Backspace key. */
+ public static final int BACKSPACE = 8;
+ /** Key code for the Escape key. */
+ public static final int ESC = 27;
+ /** Key code for the Shift key. */
+ public static final int SHIFT = 16;
+
+ private static final Set<Integer> nonText;
+
+ static {
+ nonText = new HashSet<>();
+ nonText.add(DOWN);
+ nonText.add(UP);
+ nonText.add(LEFT);
+ nonText.add(RIGHT);
+
+ nonText.add(SHIFT);
+ nonText.add(ESC);
+ }
+
+ /**
+ * Checks if the Alt key is pressed in the given modifier mask.
+ *
+ * @param modifiersEx the extended modifier mask from {@link java.awt.event.KeyEvent#getModifiersEx()}
+ * @return {@code true} if Alt is pressed
+ */
+ public static boolean isAltPressed(final int modifiersEx) {
+ return (modifiersEx | InputEvent.ALT_DOWN_MASK) == modifiersEx;
+ }
+
+ /**
+ * Checks if the Ctrl key is pressed in the given modifier mask.
+ *
+ * @param modifiersEx the extended modifier mask from {@link java.awt.event.KeyEvent#getModifiersEx()}
+ * @return {@code true} if Ctrl is pressed
+ */
+ public static boolean isCtrlPressed(final int modifiersEx) {
+ return (modifiersEx | InputEvent.CTRL_DOWN_MASK) == modifiersEx;
+ }
+
+ /**
+ * Checks if the Shift key is pressed in the given modifier mask.
+ *
+ * @param modifiersEx the extended modifier mask from {@link java.awt.event.KeyEvent#getModifiersEx()}
+ * @return {@code true} if Shift is pressed
+ */
+ public static boolean isShiftPressed(final int modifiersEx) {
+ return (modifiersEx | InputEvent.SHIFT_DOWN_MASK) == modifiersEx;
+ }
+
+ /**
+ * Determines whether the given key code represents a text-producing key
+ * (as opposed to navigation or modifier keys like arrows, Shift, Escape).
+ *
+ * @param keyCode the key code to check
+ * @return {@code true} if the key produces text input
+ */
+ public static boolean isText(final int keyCode) {
+ return !nonText.contains(keyCode);
+ }
+
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui.humaninput;
+
+import eu.svjatoslav.aukio.e3d.gui.ViewPanel;
+
+import java.awt.event.KeyEvent;
+
+/**
+ * This is the process:
+ * <p>
+ * 1. Component receives focus, perhaps because user clicked on it with the mouse.
+ * 2. Now component will receive user key press and release events from the keyboard.
+ * 3. Component loses focus. Perhaps user chose another component to interact with.
+ */
+public interface KeyboardInputHandler {
+
+ /**
+ * Called when the component loses keyboard focus.
+ *
+ * @param viewPanel the view panel that owns this handler
+ * @return {@code true} if view needs to be re-rendered
+ */
+ boolean focusLost(ViewPanel viewPanel);
+
+ /**
+ * Called when the component receives keyboard focus.
+ *
+ * @param viewPanel the view panel that owns this handler
+ * @return {@code true} if view needs to be re-rendered
+ */
+ boolean focusReceived(ViewPanel viewPanel);
+
+ /**
+ * Called when a key is pressed while the component has focus.
+ *
+ * @param event the key event
+ * @param viewPanel the view panel that owns this handler
+ * @return {@code true} if view needs to be re-rendered
+ */
+ boolean keyPressed(KeyEvent event, ViewPanel viewPanel);
+
+ /**
+ * Called when a key is released while the component has focus.
+ *
+ * @param event the key event
+ * @param viewPanel the view panel that owns this handler
+ * @return {@code true} if view needs to be re-rendered
+ */
+ boolean keyReleased(KeyEvent event, ViewPanel viewPanel);
+
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui.humaninput;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point2D;
+
+/**
+ * Represents mouse event.
+ */
+public class MouseEvent {
+
+ /** Mouse over (no button pressed). */
+ public static final int BUTTON_HOVER = 0;
+ /** Left mouse button. */
+ public static final int BUTTON_LEFT = 1;
+ /** Middle mouse button. */
+ public static final int BUTTON_MIDDLE = 2;
+ /** Right mouse button. */
+ public static final int BUTTON_RIGHT = 3;
+ /**
+ * Mouse back button. AWT on Linux reports X buttons 8/9 as 6/7 and
+ * delivers them only as PRESSED/RELEASED, never CLICKED; other
+ * platforms may use 4/5 — handle both.
+ */
+ public static final int BUTTON_BACK = 6;
+ /** Mouse forward button (AWT 7 on Linux = X button 9). */
+ public static final int BUTTON_FORWARD = 7;
+
+ /**
+ * Mouse coordinate in screen space (pixels) relative to top left corner of the screen
+ * when mouse button was clicked.
+ */
+ public Point2D coordinate;
+
+ /**
+ * One of {@link #BUTTON_HOVER}, {@link #BUTTON_LEFT},
+ * {@link #BUTTON_MIDDLE}, {@link #BUTTON_RIGHT}.
+ */
+ public int button;
+
+ MouseEvent(final int x, final int y, final int button) {
+ this(new Point2D(x, y), button);
+ }
+
+ MouseEvent(final Point2D coordinate, final int button) {
+ this.coordinate = coordinate;
+ this.button = button;
+ }
+
+ @Override
+ public String toString() {
+ return "MouseEvent{" +
+ "coordinate=" + coordinate +
+ ", button=" + button +
+ '}';
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui.humaninput;
+
+/**
+ * Interface that allows to handle mouse events.
+ */
+public interface MouseInteractionController {
+
+ /**
+ * Called when mouse is clicked on component.
+ *
+ * @param button the mouse button that was clicked (1 = left, 2 = middle, 3 = right)
+ * @return {@code true} if view update is needed as a consequence of this mouse click
+ */
+ boolean mouseClicked(int button);
+
+ /**
+ * Called when mouse is clicked on component, with the exact texture
+ * coordinates of the clicked point when the hit shape is textured.
+ *
+ * <p>The default implementation ignores the texture coordinates and
+ * delegates to {@link #mouseClicked(int)}. Components that need to know
+ * WHERE on their surface the click landed (e.g. to forward the click
+ * into a captured application window) override this method.</p>
+ *
+ * @param button the mouse button that was clicked (1 = left, 2 = middle, 3 = right)
+ * @param textureU texture-space X of the clicked point in primary-texture
+ * pixels, or {@link Double#NaN} when the hit shape has no texture
+ * @param textureV texture-space Y of the clicked point in primary-texture
+ * pixels, or {@link Double#NaN} when the hit shape has no texture
+ * @return {@code true} if view update is needed as a consequence of this mouse click
+ */
+ default boolean mouseClicked(final int button, final double textureU,
+ final double textureV) {
+ return mouseClicked(button);
+ }
+
+ /**
+ * Called when mouse is clicked on component, additionally carrying the
+ * keyboard focus stack of the dispatching view.
+ *
+ * <p>Components that take keyboard focus on click should override THIS
+ * method rather than reaching for a stored ViewPanel reference: scenes
+ * built headlessly (golden-image harness) construct components with a
+ * null panel, but the dispatching view always has a focus stack.</p>
+ *
+ * <p>The default implementation ignores the focus stack and delegates
+ * to {@link #mouseClicked(int, double, double)}.</p>
+ *
+ * @param button the mouse button that was clicked (1 = left, 2 = middle, 3 = right)
+ * @param textureU texture-space X of the clicked point, or {@link Double#NaN}
+ * @param textureV texture-space Y of the clicked point, or {@link Double#NaN}
+ * @param focusStack keyboard focus stack of the dispatching view
+ * @return {@code true} if view update is needed as a consequence of this mouse click
+ */
+ default boolean mouseClicked(final int button, final double textureU,
+ final double textureV,
+ final KeyboardFocusStack focusStack) {
+ return mouseClicked(button, textureU, textureV);
+ }
+
+ /**
+ * Called when the mouse wheel is turned while this component has
+ * keyboard focus. Both axes are reported: horizontal wheel input
+ * arrives from AWT as shift-modified vertical rotation and is
+ * separated by the input manager.
+ *
+ * <p>Returning {@code false} lets the wheel fall through to the
+ * default camera movement.</p>
+ *
+ * @param verticalUnits wheel notches; positive = wheel away from
+ * the user (content scrolls down)
+ * @param horizontalUnits wheel notches; positive = scroll right
+ * @return {@code true} if the component consumed the scroll
+ */
+ default boolean mouseWheelMoved(final int verticalUnits,
+ final int horizontalUnits) {
+ return false;
+ }
+
+ /**
+ * Called when the mouse hovers over this component, with the exact
+ * texture coordinates of the hovered point when the hit shape is
+ * textured (NaN otherwise). Allows components that forward input into
+ * a captured application window to track the pointer position.
+ *
+ * @return {@code true} if view update is needed
+ */
+ default boolean mouseHover(final double textureU, final double textureV) {
+ return false;
+ }
+
+ /**
+ * Called when mouse gets over given component.
+ *
+ * @return <code>true</code> if view update is needed as a consequence of this mouse enter.
+ */
+ boolean mouseEntered();
+
+ /**
+ * Called when mouse leaves screen area occupied by component.
+ *
+ * @return <code>true</code> if view update is needed as a consequence of this mouse exit.
+ */
+ boolean mouseExited();
+
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui.humaninput;
+
+import eu.svjatoslav.aukio.e3d.geometry.Camera;
+import eu.svjatoslav.aukio.e3d.gui.ViewPanel;
+import eu.svjatoslav.aukio.e3d.gui.FrameListener;
+
+import java.awt.event.KeyEvent;
+
+/**
+ * Default keyboard input handler that translates arrow key presses into camera (avatar)
+ * movement through the 3D world.
+ *
+ * <p>This handler is automatically registered as the default focus owner in the
+ * {@link KeyboardFocusStack}. It listens for arrow key presses on each frame and
+ * applies acceleration to the avatar's movement vector accordingly:</p>
+ * <ul>
+ * <li><b>Up arrow</b> - move forward (positive Z)</li>
+ * <li><b>Down arrow</b> - move backward (negative Z)</li>
+ * <li><b>Right arrow</b> - move right (positive X)</li>
+ * <li><b>Left arrow</b> - move left (negative X)</li>
+ * </ul>
+ *
+ * <p>Movement acceleration scales with the time delta between frames for smooth,
+ * frame-rate-independent navigation. It also scales with current speed for a natural
+ * acceleration curve.</p>
+ *
+ * @see KeyboardFocusStack the focus system that manages this handler
+ * @see Camera the camera/viewer that this handler moves
+ */
+public class WorldNavigationUserInputTracker implements KeyboardInputHandler, FrameListener {
+
+ /**
+ * Creates a new world navigation input tracker.
+ */
+ public WorldNavigationUserInputTracker() {
+ }
+
+ @Override
+ public boolean onFrame(final ViewPanel viewPanel,
+ final int millisecondsSinceLastFrame) {
+
+ final InputManager inputManager = viewPanel.getInputManager();
+
+ final Camera camera = viewPanel.getCamera();
+
+ final double actualAcceleration = (long) millisecondsSinceLastFrame
+ * camera.cameraAcceleration
+ * (1 + (camera.getMovementSpeed() / 10));
+
+ if (inputManager.isKeyPressed(KeyboardHelper.UP))
+ camera.getMovementVector().z += actualAcceleration;
+
+ if (inputManager.isKeyPressed(KeyboardHelper.DOWN))
+ camera.getMovementVector().z -= actualAcceleration;
+
+ if (inputManager.isKeyPressed(KeyboardHelper.RIGHT))
+ camera.getMovementVector().x += actualAcceleration;
+
+ if (inputManager.isKeyPressed(KeyboardHelper.LEFT))
+ camera.getMovementVector().x -= actualAcceleration;
+
+ camera.enforceSpeedLimit();
+
+ return false;
+ }
+
+ @Override
+ public boolean focusLost(final ViewPanel viewPanel) {
+ viewPanel.removeFrameListener(this);
+ return false;
+ }
+
+ @Override
+ public boolean focusReceived(final ViewPanel viewPanel) {
+ viewPanel.addFrameListener(this);
+ return false;
+ }
+
+ @Override
+ public boolean keyPressed(final KeyEvent event, final ViewPanel viewContext) {
+ return false;
+ }
+
+ @Override
+ public boolean keyReleased(final KeyEvent event, final ViewPanel viewContext) {
+ return false;
+ }
+
+}
--- /dev/null
+/**
+ * Provides input device tracking (keyboard, mouse) and event forwarding to virtual components.
+ *
+ * @see eu.svjatoslav.aukio.e3d.gui.humaninput.InputManager
+ * @see eu.svjatoslav.aukio.e3d.gui.humaninput.KeyboardFocusStack
+ */
+package eu.svjatoslav.aukio.e3d.gui.humaninput;
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+
+/**
+ * Graphical user interface components for the Aukio 3D engine.
+ *
+ * <p>This package provides the primary integration points for embedding 3D rendering
+ * into Java applications using Swing/AWT.</p>
+ *
+ * <p>Key classes:</p>
+ * <ul>
+ * <li>{@link eu.svjatoslav.aukio.e3d.gui.ViewPanel} - The main rendering surface (JPanel)</li>
+ * <li>{@link eu.svjatoslav.aukio.e3d.gui.ViewFrame} - A JFrame with embedded ViewPanel</li>
+ * <li>{@link eu.svjatoslav.aukio.e3d.geometry.Camera} - Represents the viewer's position and orientation</li>
+ * <li>{@link eu.svjatoslav.aukio.e3d.gui.DeveloperTools} - Debugging and profiling utilities</li>
+ * </ul>
+ *
+ * @see eu.svjatoslav.aukio.e3d.gui.ViewPanel
+ * @see eu.svjatoslav.aukio.e3d.geometry.Camera
+ */
+
+package eu.svjatoslav.aukio.e3d.gui;
+import eu.svjatoslav.aukio.e3d.geometry.Camera;
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui.spacemouse;
+
+import eu.svjatoslav.aukio.e3d.geometry.Camera;
+import eu.svjatoslav.aukio.e3d.gui.FrameListener;
+import eu.svjatoslav.aukio.e3d.gui.ViewPanel;
+import eu.svjatoslav.aukio.e3d.math.Matrix3x3;
+import eu.svjatoslav.aukio.e3d.math.Quaternion;
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+
+/**
+ * Applies SpaceNavigator 6DOF input to the camera, every frame:
+ *
+ * <ul>
+ * <li>push/pull/slide the cap → camera moves DIRECTLY, proportional
+ * to deflection (the cap senses pressure, unlike a keyboard):
+ * velocity = deflection × top speed, applied to the camera
+ * position every frame. Release the cap and movement stops
+ * instantly — no acceleration ramp, no coasting</li>
+ * <li>tilt/twist the cap → camera yaw/pitch. Applied as an
+ * incremental delta on top of the current orientation, so it
+ * composes with head tracking (HeadLookController folds the
+ * delta into its base pose, same as mouse drags) and with mouse
+ * drag look</li>
+ * <li>left button → brake (zero the keyboard/wheel movement vector)</li>
+ * </ul>
+ *
+ * <p>Cap roll is measured but deliberately not applied — consistent
+ * with head tracking, the world horizon stays level.</p>
+ */
+public final class SpaceMouseController implements FrameListener {
+
+ /**
+ * Raw-axis → camera sign mapping. Hardware conventions are
+ * documented in {@link SpaceNavigatorHid}. Camera conventions:
+ * movementVector.x+ = strafe right, .z+ = forward, .y+ = up;
+ * yaw+ = turn left, pitch+ = look up.
+ */
+ private static final double STRAFE_SIGN = 1.0; // push right → strafe right
+ private static final double FORWARD_SIGN = -1.0; // push away → forward (live-verified)
+ private static final double VERTICAL_SIGN = 1.0; // press down → move down (live-verified)
+ private static final double YAW_SIGN = -1.0; // twist clockwise → turn right
+ private static final double PITCH_SIGN = 1.0; // tilt top away → look up (live-verified)
+
+ /** Raw counts below this are treated as "hands off". */
+ private static final int DEADBAND = 1;
+
+ /** Camera speed at full cap deflection, as a multiple of the
+ * keyboard top speed ({@link Camera#SPEED_LIMIT}). 3.0 = direct
+ * drive tops out at 3x the keyboard's capped speed (2026-09-10 —
+ * keyboard cap was the hidden ceiling behind "still too slow"). */
+ private static final double TRANSLATION_SPEED_FACTOR = 5.0;
+
+ /** Degrees of view yaw per frame at full cap twist
+ * (2x pitch 2026-09-10 — twist felt under-responsive). */
+ private static final double ROTATION_YAW_DEGREES = 3.0;
+
+ /** Degrees of view pitch per frame at full cap tilt. */
+ private static final double ROTATION_PITCH_DEGREES = 1.5;
+
+ private final SpaceNavigatorHid device;
+ private final ViewPanel viewPanel;
+
+ private double sensitivity = 5.0;
+ private boolean leftButtonWasPressed;
+
+ public SpaceMouseController(final SpaceNavigatorHid device,
+ final ViewPanel viewPanel) {
+ this.device = device;
+ this.viewPanel = viewPanel;
+ }
+
+ public double getSensitivity() {
+ return sensitivity;
+ }
+
+ public void setSensitivity(final double sensitivity) {
+ this.sensitivity = sensitivity;
+ }
+
+ @Override
+ public boolean onFrame(final ViewPanel viewPanel,
+ final int millisecondsSinceLastFrame) {
+ if (!device.isRunning())
+ return false;
+
+ final Camera camera = viewPanel.getCamera();
+ boolean changed = false;
+
+ // Frame-rate independent scaling, 60 fps baseline.
+ final double dt = millisecondsSinceLastFrame / 16.6667;
+
+ final double strafe = shaped(device.getTx()) * STRAFE_SIGN;
+ final double forward = shaped(device.getTy()) * FORWARD_SIGN;
+ final double vertical = shaped(device.getTz()) * VERTICAL_SIGN;
+ if (strafe != 0 || forward != 0 || vertical != 0) {
+ // Direct proportional drive: deflection maps to velocity
+ // (full deflection = keyboard top speed), applied straight
+ // to the camera position. No movement vector, no friction —
+ // releasing the cap stops the camera this very frame.
+ final Matrix3x3 m = camera.getTransform().getRotation()
+ .toMatrix();
+ final Point3D location = camera.getTransform()
+ .getTranslation();
+ final double step = TRANSLATION_SPEED_FACTOR
+ * Camera.SPEED_LIMIT * Camera.SPEED_MULTIPLIER
+ * millisecondsSinceLastFrame * sensitivity;
+ location.x += (m.m20 * forward + m.m00 * strafe) * step;
+ location.y += (m.m21 * forward + m.m01 * strafe) * step;
+ location.z += (m.m22 * forward + m.m02 * strafe) * step;
+ location.y += vertical * step;
+ changed = true;
+ }
+
+ final double yawDelta = shaped(device.getRz()) * YAW_SIGN;
+ final double pitchDelta = shaped(device.getRx()) * PITCH_SIGN;
+ if (yawDelta != 0 || pitchDelta != 0) {
+ final double[] angles = camera.getTransform().getRotation()
+ .toAngles();
+ double yaw = angles[0] + yawDelta
+ * Math.toRadians(ROTATION_YAW_DEGREES)
+ * sensitivity * dt;
+ double pitch = angles[1] + pitchDelta
+ * Math.toRadians(ROTATION_PITCH_DEGREES)
+ * sensitivity * dt;
+ pitch = Math.max(-Math.PI / 2 + 0.001,
+ Math.min(Math.PI / 2 - 0.001, pitch));
+ camera.getTransform().getRotation().set(
+ Quaternion.fromAngles(yaw, pitch, 0));
+ changed = true;
+ }
+
+ final boolean leftPressed = (device.getButtons() & 1) != 0;
+ if (leftPressed && !leftButtonWasPressed) {
+ camera.getMovementVector().x = 0;
+ camera.getMovementVector().y = 0;
+ camera.getMovementVector().z = 0;
+ changed = true;
+ }
+ leftButtonWasPressed = leftPressed;
+
+ return changed;
+ }
+
+ /**
+ * Deadband + quadratic response: raw axis (−350..350) → −1..1.
+ * Quadratic keeps fine control near the center while preserving
+ * full speed at the rim.
+ */
+ private static double shaped(final int raw) {
+ final int magnitude = Math.abs(raw);
+ if (magnitude < DEADBAND)
+ return 0;
+ final double v = (magnitude - DEADBAND)
+ / (SpaceNavigatorHid.FULL_DEFLECTION - DEADBAND);
+ return Math.copySign(v * v, raw);
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui.spacemouse;
+
+import eu.svjatoslav.aukio.e3d.gui.ViewPanel;
+
+/**
+ * Hot-plug manager for the SpaceNavigator 6DOF mouse. Polls for the
+ * device every two seconds:
+ *
+ * <ul>
+ * <li>plugged in → open the HID pipe, attach a
+ * {@link SpaceMouseController} to the view's frame listeners</li>
+ * <li>unplugged (read error) → stop and detach</li>
+ * <li>plugged back in → fresh device instance</li>
+ * </ul>
+ *
+ * <p>Permission failures are reported once, then retried silently —
+ * the user may install the udev rule while the application runs.</p>
+ */
+public final class SpaceMouseManager {
+
+ private static final long POLL_INTERVAL_MS = 2000;
+
+ private final ViewPanel viewPanel;
+ private final Thread thread;
+
+ private volatile boolean running = true;
+ private SpaceNavigatorHid device;
+ private SpaceMouseController controller;
+ private boolean failureReported;
+
+ public SpaceMouseManager(final ViewPanel viewPanel) {
+ this.viewPanel = viewPanel;
+ thread = new Thread(this::pollLoop, "spacemouse-hotplug");
+ thread.setDaemon(true);
+ }
+
+ public void start() {
+ thread.start();
+ }
+
+ /** Active device, or null when no SpaceNavigator is connected. */
+ public SpaceNavigatorHid getDevice() {
+ return device;
+ }
+
+ /** Active controller, or null when no SpaceNavigator is connected. */
+ public SpaceMouseController getController() {
+ return controller;
+ }
+
+ public void stop() {
+ running = false;
+ // Wake the 2 s poll sleep; without the interrupt the join below
+ // burns its full 1 s timeout on the EDT at every window close.
+ thread.interrupt();
+ try {
+ thread.join(1000);
+ } catch (final InterruptedException e) {
+ Thread.currentThread().interrupt();
+ }
+ disconnect();
+ }
+
+ private void pollLoop() {
+ while (running) {
+ poll();
+ try {
+ Thread.sleep(POLL_INTERVAL_MS);
+ } catch (final InterruptedException e) {
+ Thread.currentThread().interrupt();
+ return;
+ }
+ }
+ }
+
+ private void poll() {
+ if (device != null && !device.isRunning()) {
+ System.out.println("spacemouse: disconnected");
+ disconnect();
+ }
+ if (device != null)
+ return;
+
+ try {
+ final SpaceNavigatorHid opened = SpaceNavigatorHid.open();
+ if (opened == null)
+ return;
+ opened.start();
+ device = opened;
+ controller = new SpaceMouseController(opened, viewPanel);
+ viewPanel.addFrameListener(controller);
+ failureReported = false;
+ System.out.println("spacemouse: SpaceNavigator detected — "
+ + "cap moves the camera, left button brakes");
+ } catch (final Exception e) {
+ device = null;
+ if (!failureReported) {
+ failureReported = true;
+ System.err.println("spacemouse unavailable: "
+ + e.getMessage());
+ }
+ }
+ }
+
+ private void disconnect() {
+ if (controller != null) {
+ viewPanel.removeFrameListener(controller);
+ controller = null;
+ }
+ if (device != null) {
+ device.stop();
+ device = null;
+ }
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui.spacemouse;
+
+import com.sun.jna.Library;
+import com.sun.jna.Memory;
+import com.sun.jna.Native;
+
+import java.io.File;
+
+/**
+ * HID transport for the 3Dconnexion SpaceNavigator 6DOF mouse
+ * (USB 046D:C626), read via the Linux hidraw interface using JNA —
+ * same approach as the RayNeo glasses transport.
+ *
+ * <p>Protocol (from libspnav/spacenavd documentation): the device
+ * sends 7-byte input reports, ONLY while the cap is deflected or a
+ * button changes — at rest the pipe is silent (so unlike the XR
+ * glasses there is no stream watchdog; silence is normal):</p>
+ *
+ * <ul>
+ * <li>report[0] = 1 — translation; int16 LE at [1,2]=X, [3,4]=Y,
+ * [5,6]=Z; full deflection ≈ ±350</li>
+ * <li>report[0] = 2 — rotation; int16 LE at [1,2]=RX, [3,4]=RY,
+ * [5,6]=RZ; full deflection ≈ ±350</li>
+ * <li>report[0] = 3 — buttons; report[1] bit0 = left, bit1 = right</li>
+ * </ul>
+ *
+ * <p>Raw axis sign conventions (SpaceNavigator hardware):</p>
+ * <ul>
+ * <li>TX: push cap right → positive</li>
+ * <li>TY: pull cap toward you → positive (live-verified)</li>
+ * <li>TZ: pull cap up → positive (live-verified)</li>
+ * <li>RX: tilt cap top away → positive</li>
+ * <li>RY: tilt cap top right → positive</li>
+ * <li>RZ: twist cap clockwise (seen from above) → positive</li>
+ * </ul>
+ *
+ * <p>Detection scans /sys/class/hidraw for HID_ID
+ * 0003:0000046D:0000C626 — the hidraw node changes on replug, so never
+ * cache the path. Unplug is detected by a read error (read returns
+ * <0).</p>
+ */
+public final class SpaceNavigatorHid {
+
+ private static final String HID_ID = "0003:0000046D:0000C626";
+
+ /** Full deflection of any axis, per the HID descriptor. */
+ public static final double FULL_DEFLECTION = 350.0;
+
+ /**
+ * Same JNA calling convention as the proven RayNeo glasses
+ * transport: static singleton mapping, Memory buffers (a raw
+ * byte[] mapping correlated with native heap corruption —
+ * "free(): invalid pointer" — under active report streaming).
+ */
+ private interface CLib extends Library {
+ CLib INSTANCE = Native.load("c", CLib.class);
+
+ int open(String path, int flags);
+
+ int close(int fd);
+
+ int read(int fd, Memory buffer, int count);
+
+ /** poll(2) on a single-element struct pollfd (8 bytes: fd, events, revents). */
+ int poll(Memory fds, int nfds, int timeout);
+ }
+
+ private final File deviceNode;
+ private final Memory readBuffer = new Memory(64);
+
+ private int fd = -1;
+ private Thread reader;
+ private volatile boolean running;
+
+ /** Latest axis state, in raw device units (±350). */
+ private volatile int tx, ty, tz, rx, ry, rz;
+ private volatile int buttons;
+ /** Set when a read error (typically unplug) killed the reader. */
+ private volatile boolean broken;
+
+ private SpaceNavigatorHid(final File deviceNode) {
+ this.deviceNode = deviceNode;
+ }
+
+ /**
+ * Finds and opens the first SpaceNavigator on the system, or null
+ * when none is plugged in. Throws when the device is present but
+ * cannot be opened (permissions — see
+ * /etc/udev/rules.d/99-spacenavigator.rules).
+ */
+ public static SpaceNavigatorHid open() {
+ final File hidrawDir = new File("/sys/class/hidraw");
+ final File[] entries = hidrawDir.listFiles();
+ if (entries == null)
+ return null;
+ for (final File entry : entries) {
+ final File uevent = new File(entry, "device/uevent");
+ if (!uevent.isFile())
+ continue;
+ try {
+ final String content = new String(
+ java.nio.file.Files.readAllBytes(uevent.toPath()));
+ if (!content.contains(HID_ID))
+ continue;
+ final File node = new File("/dev", entry.getName());
+ final SpaceNavigatorHid hid = new SpaceNavigatorHid(node);
+ hid.openNode();
+ return hid;
+ } catch (final Exception e) {
+ throw new RuntimeException("SpaceNavigator found at "
+ + entry.getName() + " but cannot be opened: "
+ + e.getMessage());
+ }
+ }
+ return null;
+ }
+
+ private void openNode() {
+ fd = CLib.INSTANCE.open(deviceNode.getAbsolutePath(),
+ 2 /* O_RDWR */);
+ if (fd < 0)
+ throw new RuntimeException("open(" + deviceNode
+ + ") failed: " + Native.getLastError());
+ }
+
+ public void start() {
+ running = true;
+ reader = new Thread(this::readLoop, "spacenavigator-hid");
+ reader.setDaemon(true);
+ reader.start();
+ }
+
+ private void readLoop() {
+ // Poll before reading: the device is SILENT at rest, so a plain
+ // blocking read never returns when idle — and close() from stop()
+ // does not wake a blocked read on Linux, which made every window
+ // close wait out the full 1 s join timeout.
+ final Memory pollfd = new Memory(8);
+ while (running) {
+ pollfd.clear();
+ pollfd.setInt(0, fd);
+ pollfd.setShort(4, (short) 0x1); // events = POLLIN
+ final int ready = CLib.INSTANCE.poll(pollfd, 1, 250);
+ if (ready == 0)
+ continue; // idle device: re-check running
+ if (ready < 0) {
+ if (Native.getLastError() == 4) // EINTR
+ continue;
+ broken = true;
+ return;
+ }
+ final short revents = pollfd.getShort(6);
+ if ((revents & 0x1) == 0) { // no POLLIN: ERR/HUP/NVAL = unplugged
+ broken = true;
+ return;
+ }
+ final int n = CLib.INSTANCE.read(fd, readBuffer, 64);
+ if (n < 0) {
+ broken = true; // unplugged
+ return;
+ }
+ if (n < 7)
+ continue;
+ final int reportId = readBuffer.getByte(0) & 0xFF;
+ if (reportId == 1) {
+ tx = readBuffer.getShort(1);
+ ty = readBuffer.getShort(3);
+ tz = readBuffer.getShort(5);
+ } else if (reportId == 2) {
+ rx = readBuffer.getShort(1);
+ ry = readBuffer.getShort(3);
+ rz = readBuffer.getShort(5);
+ } else if (reportId == 3) {
+ buttons = readBuffer.getByte(1) & 0xFF;
+ }
+ }
+ }
+
+ /** True while the device is connected and the reader is alive. */
+ public boolean isRunning() {
+ return running && !broken;
+ }
+
+ public int getTx() { return tx; }
+ public int getTy() { return ty; }
+ public int getTz() { return tz; }
+ public int getRx() { return rx; }
+ public int getRy() { return ry; }
+ public int getRz() { return rz; }
+ public int getButtons() { return buttons; }
+
+ public void stop() {
+ running = false;
+ // Join first: the poll loop notices the flag within 250 ms. Closing
+ // the fd before the reader is dead risks the fd number being reused
+ // under a concurrent open while the reader is mid-read.
+ if (reader != null) {
+ try {
+ reader.join(1000);
+ } catch (final InterruptedException e) {
+ Thread.currentThread().interrupt();
+ }
+ reader = null;
+ }
+ if (fd >= 0) {
+ CLib.INSTANCE.close(fd);
+ fd = -1;
+ }
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui.textEditorComponent;
+
+/**
+ * A character in a text editor.
+ */
+public class Character {
+
+ /**
+ * The character value.
+ */
+ char value;
+
+ /**
+ * Creates a character with the given value.
+ *
+ * @param value the character value
+ */
+ public Character(final char value) {
+ this.value = value;
+ }
+
+ boolean hasValue() {
+ return value != ' ';
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui.textEditorComponent;
+
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+
+/**
+ * A look and feel of a text editor.
+ */
+public class LookAndFeel {
+
+ /** Default foreground (text) color. */
+ public Color foreground = new Color(255, 255, 255);
+
+ /** Default background color. */
+ public Color background = new Color(20, 20, 20, 255);
+
+ /** Background color for tab stop positions. */
+ public Color tabStopBackground = new Color(25, 25, 25, 255);
+
+ /** Cursor foreground color. */
+ public Color cursorForeground = new Color(255, 255, 255);
+
+ /** Cursor background color. */
+ public Color cursorBackground = new Color(255, 0, 0);
+
+ /** Selection foreground color. */
+ public Color selectionForeground = new Color(255, 255, 255);
+
+ /** Selection background color. */
+ public Color selectionBackground = new Color(0, 80, 80);
+
+ /**
+ * Creates a look and feel with default colors.
+ */
+ public LookAndFeel() {
+ }
+
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui.textEditorComponent;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * A page in a text editor.
+ */
+public class Page {
+
+ /**
+ * The text lines.
+ */
+ public List<TextLine> rows = new ArrayList<>();
+
+ /**
+ * Creates a new empty page.
+ */
+ public Page() {
+ }
+
+ /**
+ * Ensures that the page has at least the specified number of lines.
+ *
+ * @param row the minimum number of lines required
+ */
+ public void ensureMaxTextLine(final int row) {
+ while (rows.size() <= row)
+ rows.add(new TextLine());
+ }
+
+ /**
+ * Returns the character at the specified location.
+ * If the location is out of bounds, returns a space.
+ *
+ * @param row the row index
+ * @param column the column index
+ * @return the character at the specified location
+ */
+ public char getChar(final int row, final int column) {
+ if (rows.size() <= row)
+ return ' ';
+ return rows.get(row).getCharForLocation(column);
+ }
+
+ /**
+ * Returns the specified line.
+ *
+ * @param row The line number.
+ * @return The line.
+ */
+ public TextLine getLine(final int row) {
+ ensureMaxTextLine(row);
+ return rows.get(row);
+ }
+
+ /**
+ * Returns the length of the specified line.
+ *
+ * @param row The line number.
+ * @return The length of the line.
+ */
+ public int getLineLength(final int row) {
+ if (rows.size() <= row)
+ return 0;
+ return rows.get(row).getLength();
+ }
+
+ /**
+ * Returns the number of lines in the page.
+ *
+ * @return The number of lines in the page.
+ */
+ public int getLinesCount() {
+ pack();
+ return rows.size();
+ }
+
+ /**
+ * Returns the text of the page.
+ *
+ * @return The text of the page.
+ */
+ public String getText() {
+ pack();
+
+ final StringBuilder result = new StringBuilder();
+ for (final TextLine textLine : rows) {
+ if (result.length() > 0)
+ result.append("\n");
+ result.append(textLine.toString());
+ }
+ return result.toString();
+ }
+
+ /**
+ * Inserts a character at the specified position.
+ *
+ * @param row the row index
+ * @param col the column index
+ * @param value the character to insert
+ */
+ public void insertCharacter(final int row, final int col, final char value) {
+ getLine(row).insertCharacter(col, value);
+ }
+
+ /**
+ * Inserts a line at the specified row.
+ *
+ * @param row the row index where to insert
+ * @param textLine the text line to insert
+ */
+ public void insertLine(final int row, final TextLine textLine) {
+ rows.add(row, textLine);
+ }
+
+ /**
+ * Removes empty lines from the end of the page.
+ */
+ private void pack() {
+ int newLength = 0;
+
+ for (int i = rows.size() - 1; i >= 0; i--)
+ if (!rows.get(i).isEmpty()) {
+ newLength = i + 1;
+ break;
+ }
+
+ if (newLength == rows.size())
+ return;
+
+ rows = rows.subList(0, newLength);
+ }
+
+ /**
+ * Removes the specified character from the page.
+ *
+ * @param row The line number.
+ * @param col The character number.
+ */
+ public void removeCharacter(final int row, final int col) {
+ if (rows.size() <= row)
+ return;
+ getLine(row).removeCharacter(col);
+ }
+
+ /**
+ * Removes the specified line from the page.
+ *
+ * @param row The line number.
+ */
+ public void removeLine(final int row) {
+ if (rows.size() <= row)
+ return;
+ rows.remove(row);
+ }
+
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui.textEditorComponent;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point2D;
+import eu.svjatoslav.aukio.e3d.gui.GuiComponent;
+import eu.svjatoslav.aukio.e3d.gui.TextPointer;
+import eu.svjatoslav.aukio.e3d.gui.ViewPanel;
+import eu.svjatoslav.aukio.e3d.gui.humaninput.KeyboardHelper;
+import eu.svjatoslav.aukio.e3d.math.Transform;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.textcanvas.TextCanvas;
+
+import java.awt.*;
+import java.awt.datatransfer.*;
+import java.awt.event.KeyEvent;
+import java.io.IOException;
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * A full-featured text editor component rendered in 3D space.
+ *
+ * <p>Extends {@link GuiComponent} to integrate keyboard focus management and mouse
+ * interaction with a multi-line text editing surface. The editor is backed by a
+ * {@link Page} model containing {@link TextLine} instances and rendered via a
+ * {@link TextCanvas}.</p>
+ *
+ * <p><b>Supported editing features:</b></p>
+ * <ul>
+ * <li>Cursor navigation with arrow keys, Home, End, Page Up, and Page Down</li>
+ * <li>Text selection via Shift + arrow keys</li>
+ * <li>Clipboard operations: Ctrl+C (copy), Ctrl+X (cut), Ctrl+V (paste), Ctrl+A (select all)</li>
+ * <li>Word-level cursor movement with Ctrl+Left and Ctrl+Right</li>
+ * <li>Tab indentation and Shift+Tab dedentation for single lines and block selections</li>
+ * <li>Backspace dedentation of selected blocks (removes 4 spaces of indentation)</li>
+ * <li>Automatic scrolling when the cursor moves beyond the visible area</li>
+ * </ul>
+ *
+ * <p><b>Usage example:</b></p>
+ * <pre>{@code
+ * // Create a look and feel (or use defaults)
+ * LookAndFeel lookAndFeel = new LookAndFeel();
+ *
+ * // Create the text editor at a position in 3D space
+ * TextEditComponent editor = new TextEditComponent(
+ * new Transform(new Point3D(0, 0, 500)), // position in world
+ * viewPanel, // the active ViewPanel
+ * new Point2D(800, 600), // size in world coordinates
+ * lookAndFeel
+ * );
+ *
+ * // Set initial content
+ * editor.setText("Hello, World!\nSecond line of text.");
+ *
+ * // Add to the scene
+ * viewPanel.getRootShapeCollection().addShape(editor);
+ * }</pre>
+ *
+ * @see GuiComponent the base class providing keyboard focus and mouse click handling
+ * @see Page the underlying text model holding all lines
+ * @see TextCanvas the rendering surface for character-based output
+ * @see LookAndFeel configurable colors for the editor's visual appearance
+ * @see TextPointer row/column pointer used for cursor and selection positions
+ */
+public class TextEditComponent extends GuiComponent implements ClipboardOwner {
+
+ private static final long serialVersionUID = -7118833957783600630L;
+
+ /**
+ * Text rows that need to be repainted.
+ */
+ private final Set<Integer> dirtyRows = new HashSet<>();
+
+
+ /**
+ * The text canvas used to render characters on screen.
+ */
+ private final TextCanvas textCanvas;
+
+ /**
+ * The number of characters the view is scrolled horizontally.
+ */
+ public int scrolledCharacters = 0;
+
+ /**
+ * The number of lines the view is scrolled vertically.
+ */
+ public int scrolledLines = 0;
+
+ /**
+ * Whether the user is currently in selection mode (Shift key held during navigation).
+ */
+ public boolean selecting = false;
+
+ /**
+ * Selection start and end pointers.
+ */
+ public TextPointer selectionStart = new TextPointer(0, 0);
+
+ /**
+ * The end position of the text selection.
+ */
+ public TextPointer selectionEnd = new TextPointer(0, 0);
+
+ /**
+ * The current cursor position in the text (row and column).
+ */
+ public TextPointer cursorLocation = new TextPointer(0, 0);
+
+ /**
+ * The page model holding all text lines.
+ */
+ Page page = new Page();
+
+ /**
+ * The look and feel configuration controlling editor colors.
+ */
+ LookAndFeel lookAndFeel;
+
+ /**
+ * If true, the page will be repainted on the next update.
+ */
+ boolean repaintPage = false;
+
+ /**
+ * Creates a new text editor component positioned in 3D space.
+ *
+ * <p>The editor dimensions in rows and columns are computed from the given world-coordinate
+ * size and the font character dimensions defined in {@link TextCanvas}. A {@link TextCanvas}
+ * is created internally and added as a child shape.</p>
+ *
+ * @param transform the position and orientation of the editor in 3D space
+ * @param viewPanel the view panel this editor belongs to
+ * @param sizeInWorldCoordinates the editor size in world coordinates (width, height);
+ * determines the number of visible columns and rows
+ * @param lookAndFeel the color configuration for the editor's visual appearance
+ */
+ public TextEditComponent(final Transform transform,
+ final ViewPanel viewPanel,
+ final Point2D sizeInWorldCoordinates,
+ LookAndFeel lookAndFeel) {
+ super(transform, viewPanel, sizeInWorldCoordinates.to3D());
+
+ this.lookAndFeel = lookAndFeel;
+ final int columns = (int) (sizeInWorldCoordinates.x / TextCanvas.FONT_CHAR_WIDTH);
+ final int rows = (int) (sizeInWorldCoordinates.y / TextCanvas.FONT_CHAR_HEIGHT);
+
+ textCanvas = new TextCanvas(
+ new Transform(),
+ new TextPointer(rows, columns),
+ lookAndFeel.foreground, lookAndFeel.background);
+
+ textCanvas.setMouseInteractionController(this);
+
+ repaintPage();
+ addShape(textCanvas);
+ }
+
+ /**
+ * Ensures the cursor stays within the visible editor area by adjusting
+ * scroll offsets when the cursor moves beyond the visible boundaries.
+ * Also clamps the cursor position so that row and column are never negative.
+ */
+ private void checkCursorBoundaries() {
+ if (cursorLocation.column < 0)
+ cursorLocation.column = 0;
+ if (cursorLocation.row < 0)
+ cursorLocation.row = 0;
+
+ // ensure chat cursor stays within vertical editor boundaries by
+ // vertical scrolling
+ if ((cursorLocation.row - scrolledLines) < 0)
+ scroll(0, cursorLocation.row - scrolledLines);
+
+ if ((((cursorLocation.row - scrolledLines) + 1)) > textCanvas.getSize().row)
+ scroll(0,
+ ((((((cursorLocation.row - scrolledLines) + 1) - textCanvas
+ .getSize().row)))));
+
+ // ensure chat cursor stays within horizontal editor boundaries by
+ // horizontal scrolling
+ if ((cursorLocation.column - scrolledCharacters) < 0)
+ scroll(cursorLocation.column - scrolledCharacters, 0);
+
+ if ((((cursorLocation.column - scrolledCharacters) + 1)) > textCanvas
+ .getSize().column)
+ scroll((((((cursorLocation.column - scrolledCharacters) + 1) - textCanvas
+ .getSize().column))), 0);
+ }
+
+ /**
+ * Clears the current text selection by setting the selection end to match
+ * the selection start, effectively making the selection empty.
+ *
+ * <p>A full page repaint is scheduled to remove the visual selection highlight.</p>
+ */
+ public void clearSelection() {
+ selectionEnd = new TextPointer(selectionStart);
+ repaintPage = true;
+ }
+
+ /**
+ * Copies the currently selected text to the system clipboard.
+ *
+ * <p>If no text is selected (i.e., selection start equals selection end),
+ * this method does nothing. Multi-line selections are joined with newline
+ * characters.</p>
+ *
+ * @see #setClipboardContents(String)
+ * @see #cutToClipboard()
+ */
+ public void copyToClipboard() {
+ if (selectionStart.compareTo(selectionEnd) == 0)
+ return;
+ // System.out.println("Copy action.");
+ final StringBuilder msg = new StringBuilder();
+
+ ensureSelectionOrder();
+
+ for (int row = selectionStart.row; row <= selectionEnd.row; row++) {
+ final TextLine textLine = page.getLine(row);
+
+ if (row == selectionStart.row) {
+ if (row == selectionEnd.row)
+ msg.append(textLine.getSubString(selectionStart.column,
+ selectionEnd.column + 1));
+ else
+ msg.append(textLine.getSubString(selectionStart.column,
+ textLine.getLength()));
+ } else {
+ msg.append('\n');
+ if (row == selectionEnd.row)
+ msg.append(textLine
+ .getSubString(0, selectionEnd.column + 1));
+ else
+ msg.append(textLine.toString());
+ }
+ }
+
+ setClipboardContents(msg.toString());
+ }
+
+ /**
+ * Cuts the currently selected text to the system clipboard.
+ *
+ * <p>This copies the selected text to the clipboard via {@link #copyToClipboard()},
+ * then deletes the selection from the page and triggers a full repaint.</p>
+ *
+ * @see #copyToClipboard()
+ * @see #deleteSelection()
+ */
+ public void cutToClipboard() {
+ copyToClipboard();
+ deleteSelection();
+ repaintPage();
+ }
+
+ /**
+ * Deletes the currently selected text from the page.
+ *
+ * <p>After deletion, the selection is cleared and the cursor is moved to
+ * the position where the selection started.</p>
+ *
+ * @see #ensureSelectionOrder()
+ */
+ public void deleteSelection() {
+ ensureSelectionOrder();
+ int ym = 0;
+
+ for (int line = selectionStart.row; line <= selectionEnd.row; line++) {
+ final TextLine currentLine = page.getLine(line - ym);
+
+ if (line == selectionStart.row) {
+ if (line == selectionEnd.row)
+
+ currentLine.cutSubString(selectionStart.column,
+ selectionEnd.column);
+ else if (selectionStart.column == 0) {
+ page.removeLine(line - ym);
+ ym++;
+ } else
+ currentLine.cutSubString(selectionStart.column,
+ currentLine.getLength() + 1);
+ } else if (line == selectionEnd.row)
+ currentLine.cutSubString(0, selectionEnd.column);
+ else {
+ page.removeLine(line - ym);
+ ym++;
+ }
+ }
+
+ clearSelection();
+ cursorLocation = new TextPointer(selectionStart);
+ }
+
+ /**
+ * Ensures that {@link #selectionStart} is smaller than
+ * {@link #selectionEnd}.
+ *
+ * <p>If the start pointer is after the end pointer (e.g., when the user
+ * selected text backwards), the two pointers are swapped so that
+ * subsequent operations can iterate from start to end.</p>
+ */
+ public void ensureSelectionOrder() {
+ if (selectionStart.compareTo(selectionEnd) > 0) {
+ final TextPointer temp = selectionEnd;
+ selectionEnd = selectionStart;
+ selectionStart = temp;
+ }
+ }
+
+ /**
+ * Retrieves the current text contents of the system clipboard.
+ *
+ * @return the clipboard text content, or an empty string if the clipboard
+ * is empty or does not contain text
+ */
+ public String getClipboardContents() {
+ String result = "";
+ final Clipboard clipboard = Toolkit.getDefaultToolkit()
+ .getSystemClipboard();
+ // odd: the Object param of getContents is not currently used
+ final Transferable contents = clipboard.getContents(null);
+ final boolean hasTransferableText = (contents != null)
+ && contents.isDataFlavorSupported(DataFlavor.stringFlavor);
+ if (hasTransferableText)
+ try {
+ result = (String) contents
+ .getTransferData(DataFlavor.stringFlavor);
+ } catch (final UnsupportedFlavorException | IOException ex) {
+ // highly unlikely since we are using a standard DataFlavor
+ System.out.println(ex);
+ }
+ // System.out.println(result);
+ return result;
+ }
+
+ /**
+ * Places the given string into the system clipboard so that it can be
+ * pasted into other applications.
+ *
+ * @param contents the text to place on the clipboard
+ * @see #getClipboardContents()
+ * @see #copyToClipboard()
+ */
+ public void setClipboardContents(final String contents) {
+ final StringSelection stringSelection = new StringSelection(contents);
+ final Clipboard clipboard = Toolkit.getDefaultToolkit()
+ .getSystemClipboard();
+ clipboard.setContents(stringSelection, stringSelection);
+ }
+
+ /**
+ * Scrolls to and positions the cursor at the beginning of the specified line.
+ *
+ * <p>The view is scrolled so the target line is visible, the cursor is placed
+ * at the start of that line (column 0), and a full repaint is triggered.</p>
+ *
+ * @param Line the zero-based line number to navigate to
+ */
+ public void goToLine(final int Line) {
+ // markNavigationLocation(Line);
+ scrolledLines = Line + 1;
+ cursorLocation.row = Line + 1;
+ cursorLocation.column = 0;
+ repaintPage();
+ }
+
+ /**
+ * Inserts the given text string at the current cursor position.
+ *
+ * <p>The text is processed character by character. Special characters are
+ * handled as editing operations:</p>
+ * <ul>
+ * <li>{@code DEL} -- deletes the character at the cursor</li>
+ * <li>{@code ENTER} -- splits the current line at the cursor</li>
+ * <li>{@code BACKSPACE} -- deletes the character before the cursor</li>
+ * </ul>
+ * <p>All other printable characters are inserted at the cursor position,
+ * advancing the cursor column by one for each character.</p>
+ *
+ * @param txt the text to insert; {@code null} values are silently ignored
+ */
+ public void insertText(final String txt) {
+ if (txt == null)
+ return;
+
+ for (final char c : txt.toCharArray()) {
+
+ if (c == KeyboardHelper.DEL) {
+ processDel();
+ continue;
+ }
+
+ if (c == KeyboardHelper.ENTER) {
+ processEnter();
+ continue;
+ }
+
+ if (c == KeyboardHelper.BACKSPACE) {
+ processBackspace();
+ continue;
+ }
+
+ // type character
+ if (KeyboardHelper.isText(c)) {
+ page.insertCharacter(cursorLocation.row, cursorLocation.column,
+ c);
+ cursorLocation.column++;
+ }
+ }
+ }
+
+ /**
+ * Handles a key press event by routing it through the editor's input processing
+ * pipeline.
+ *
+ * <p>This method delegates to the parent {@link GuiComponent#keyPressed(KeyEvent, ViewPanel)}
+ * (which handles ESC for focus release), then processes the key event for text editing,
+ * marks the affected row as dirty, adjusts scroll boundaries, and repaints as needed.</p>
+ *
+ * @param event the keyboard event
+ * @param viewPanel the view panel that dispatched this event
+ * @return always {@code true}, indicating the event was consumed
+ */
+ @Override
+ public boolean keyPressed(final KeyEvent event, final ViewPanel viewPanel) {
+ super.keyPressed(event, viewPanel);
+
+ processKeyEvent(event);
+
+ markRowDirty();
+
+ checkCursorBoundaries();
+
+ repaintWhatNeeded();
+ return true;
+ }
+
+ /**
+ * Called when this editor loses ownership of the system clipboard.
+ *
+ * <p>This is an empty implementation of the {@link ClipboardOwner} interface;
+ * no action is taken when clipboard ownership is lost.</p>
+ *
+ * @param aClipboard the clipboard that this editor previously owned
+ * @param aContents the contents that were previously placed on the clipboard
+ */
+ @Override
+ public void lostOwnership(final Clipboard aClipboard,
+ final Transferable aContents) {
+ // do nothing
+ }
+
+ /**
+ * Marks the current cursor row as dirty, scheduling it for repaint on the
+ * next rendering cycle.
+ */
+ public void markRowDirty() {
+ dirtyRows.add(cursorLocation.row);
+ }
+
+ /**
+ * Pastes text from the system clipboard at the current cursor position.
+ *
+ * @see #getClipboardContents()
+ * @see #insertText(String)
+ */
+ public void pasteFromClipboard() {
+ insertText(getClipboardContents());
+ }
+
+ /**
+ * Processes the backspace key action.
+ *
+ * <p>If there is no active selection, deletes the character before the cursor.
+ * If the cursor is at the beginning of a line, merges the current line with the
+ * previous one. If there is an active selection, dedents the selected lines by
+ * removing up to 4 leading spaces (block dedentation).</p>
+ */
+ private void processBackspace() {
+ if (selectionStart.compareTo(selectionEnd) == 0) {
+ // erase single character
+ if (cursorLocation.column > 0) {
+ cursorLocation.column--;
+ page.removeCharacter(cursorLocation.row, cursorLocation.column);
+ // System.out.println(lines.get(currentCursor.line).toString());
+ } else if (cursorLocation.row > 0) {
+ cursorLocation.row--;
+ final int currentLineLength = page
+ .getLineLength(cursorLocation.row);
+ cursorLocation.column = currentLineLength;
+ page.getLine(cursorLocation.row)
+ .insertTextLine(currentLineLength,
+ page.getLine(cursorLocation.row + 1));
+ page.removeLine(cursorLocation.row + 1);
+ repaintPage = true;
+ }
+ } else {
+ // dedent multiple lines
+ ensureSelectionOrder();
+ // scan if enough space exists
+ for (int y = selectionStart.row; y < selectionEnd.row; y++)
+ if (page.getLine(y).getIndent() < 4)
+ return;
+
+ for (int y = selectionStart.row; y < selectionEnd.row; y++)
+ page.getLine(y).cutFromBeginning(4);
+
+ repaintPage = true;
+ }
+ }
+
+ /**
+ * Processes keyboard shortcuts involving the Ctrl modifier key.
+ *
+ * <p>Supported combinations:</p>
+ * <ul>
+ * <li>Ctrl+A -- select all text</li>
+ * <li>Ctrl+X -- cut selected text to clipboard</li>
+ * <li>Ctrl+C -- copy selected text to clipboard</li>
+ * <li>Ctrl+V -- paste from clipboard</li>
+ * <li>Ctrl+Right -- skip to the beginning of the next word</li>
+ * <li>Ctrl+Left -- skip to the beginning of the previous word</li>
+ * </ul>
+ *
+ * @param keyCode the key code of the pressed key (combined with Ctrl)
+ */
+ private void processCtrlCombinations(final int keyCode) {
+
+ if ((char) keyCode == 'A') { // CTRL + A -- select all
+ final int lastLineIndex = page.getLinesCount() - 1;
+ selectionStart = new TextPointer(0, 0);
+ selectionEnd = new TextPointer(lastLineIndex,
+ page.getLineLength(lastLineIndex));
+ repaintPage();
+ }
+
+ // CTRL + X -- cut
+ if ((char) keyCode == 'X')
+ cutToClipboard();
+
+ // CTRL + C -- copy
+ if ((char) keyCode == 'C')
+ copyToClipboard();
+
+ // CTRL + V -- paste
+ if ((char) keyCode == 'V')
+ pasteFromClipboard();
+
+ if (keyCode == 39) { // RIGHT
+ // skip to the beginning of the next word
+
+ for (int x = cursorLocation.column; x < (page
+ .getLineLength(cursorLocation.row) - 1); x++)
+ if ((page.getChar(cursorLocation.row, x) == ' ')
+ && (page.getChar(cursorLocation.row, x + 1) != ' ')) {
+ // beginning of the next word is found
+ cursorLocation.column = x + 1;
+ return;
+ }
+
+ cursorLocation.column = page.getLineLength(cursorLocation.row);
+ return;
+ }
+
+ if (keyCode == 37) { // Left
+
+ // skip to the beginning of the previous word
+ for (int x = cursorLocation.column - 2; x >= 0; x--)
+ if ((page.getChar(cursorLocation.row, x) == ' ')
+ & (page.getChar(cursorLocation.row, x + 1) != ' ')) {
+ cursorLocation.column = x + 1;
+ return;
+ }
+
+ cursorLocation.column = 0;
+ }
+ }
+
+ /**
+ * Processes the Delete key action.
+ *
+ * <p>If there is no active selection, deletes the character at the cursor position.
+ * If the cursor is at the end of the line, the next line is merged into the current one.
+ * If there is an active selection, the entire selection is deleted.</p>
+ */
+ public void processDel() {
+ if (selectionStart.compareTo(selectionEnd) == 0) {
+ // is there still some text right to the cursor ?
+ if (cursorLocation.column < page.getLineLength(cursorLocation.row))
+ page.removeCharacter(cursorLocation.row, cursorLocation.column);
+ else {
+ page.getLine(cursorLocation.row).insertTextLine(
+ cursorLocation.column,
+ page.getLine(cursorLocation.row + 1));
+ page.removeLine(cursorLocation.row + 1);
+ repaintPage = true;
+ }
+ } else {
+ deleteSelection();
+ repaintPage = true;
+ }
+ }
+
+ /**
+ * Processes the Enter key action by splitting the current line at the cursor position.
+ *
+ * <p>Everything to the right of the cursor is moved to a new line inserted
+ * below. The cursor moves to the beginning of the new line.</p>
+ */
+ private void processEnter() {
+ final TextLine currentLine = page.getLine(cursorLocation.row);
+ // move everything right to the cursor into new line
+ final TextLine newLine = currentLine.getSubLine(cursorLocation.column,
+ currentLine.getLength());
+ page.insertLine(cursorLocation.row + 1, newLine);
+
+ // trim existing line
+ page.getLine(cursorLocation.row).cutUntilEnd(cursorLocation.column);
+ repaintPage = true;
+
+ cursorLocation.row++;
+ cursorLocation.column = 0;
+ }
+
+ /**
+ * Routes a keyboard event to the appropriate handler based on modifier keys
+ * and key codes.
+ *
+ * <p>Handles Ctrl combinations, Tab/Shift+Tab, text input, Shift-based selection,
+ * and cursor navigation keys (Home, End, arrows, Page Up/Down). Alt key events
+ * are ignored.</p>
+ *
+ * @param event the keyboard event to process
+ */
+ private void processKeyEvent(final KeyEvent event) {
+ final int modifiers = event.getModifiersEx();
+ final int keyCode = event.getKeyCode();
+ final char keyChar = event.getKeyChar();
+
+ // System.out.println("Keycode:" + keyCode s+ ", keychar:" + keyChar);
+
+ if (KeyboardHelper.isAltPressed(modifiers))
+ return;
+
+ if (KeyboardHelper.isCtrlPressed(modifiers)) {
+ processCtrlCombinations(keyCode);
+ return;
+ }
+
+ if (keyCode == KeyboardHelper.TAB) {
+ processTab(modifiers);
+ return;
+ }
+
+ clearSelection();
+
+ if (KeyboardHelper.isText(keyCode)) {
+ insertText(String.valueOf(keyChar));
+ return;
+ }
+
+ if (KeyboardHelper.isShiftPressed(modifiers)) {
+ if (!selecting)
+ attemptSelectionStart:{
+
+ if (keyChar == 65535)
+ if (keyCode == 16)
+ break attemptSelectionStart;
+ if (((keyChar >= 32) & (keyChar <= 128)) | (keyChar == 10)
+ | (keyChar == 8) | (keyChar == 9))
+ break attemptSelectionStart;
+
+ selectionStart = new TextPointer(cursorLocation);
+ selectionEnd = selectionStart;
+ selecting = true;
+ repaintPage();
+ }
+ } else
+ selecting = false;
+
+ if (keyCode == KeyboardHelper.HOME) {
+ cursorLocation.column = 0;
+ return;
+ }
+ if (keyCode == KeyboardHelper.END) {
+ cursorLocation.column = page.getLineLength(cursorLocation.row);
+ return;
+ }
+
+ // process cursor keys
+ if (keyCode == KeyboardHelper.DOWN) {
+ markRowDirty();
+ cursorLocation.row++;
+ return;
+ }
+
+ if (keyCode == KeyboardHelper.UP) {
+ markRowDirty();
+ cursorLocation.row--;
+ return;
+ }
+
+ if (keyCode == KeyboardHelper.RIGHT) {
+ cursorLocation.column++;
+ return;
+ }
+
+ if (keyCode == KeyboardHelper.LEFT) {
+ cursorLocation.column--;
+ return;
+ }
+
+ if (keyCode == KeyboardHelper.PGDOWN) {
+ cursorLocation.row += textCanvas.getSize().row;
+ repaintPage();
+ return;
+ }
+
+ if (keyCode == KeyboardHelper.PGUP) {
+ cursorLocation.row -= textCanvas.getSize().row;
+ repaintPage = true;
+ }
+
+ }
+
+ /**
+ * Processes the Tab key action for indentation and dedentation.
+ *
+ * <p>Behavior depends on modifiers and selection state:</p>
+ * <ul>
+ * <li><strong>Shift+Tab with selection:</strong> dedents all selected lines by
+ * removing up to 4 leading spaces, if all lines have sufficient indentation</li>
+ * <li><strong>Shift+Tab without selection:</strong> dedents the current line by
+ * removing 4 leading spaces and moving the cursor back</li>
+ * <li><strong>Tab with selection:</strong> indents all selected lines by adding
+ * 4 leading spaces</li>
+ * </ul>
+ *
+ * @param modifiers the keyboard modifier flags from the key event
+ */
+ private void processTab(final int modifiers) {
+ if (KeyboardHelper.isShiftPressed(modifiers)) {
+ if (selectionStart.compareTo(selectionEnd) != 0) {
+ // dedent multiple lines
+ ensureSelectionOrder();
+
+ identSelection:
+ {
+ // check that indentation is possible
+ for (int y = selectionStart.row; y < selectionEnd.row; y++) {
+ final TextLine textLine = page.getLine(y);
+
+ if (!textLine.isEmpty())
+ if (textLine.getIndent() < 4)
+ break identSelection;
+ }
+
+ for (int y = selectionStart.row; y < selectionEnd.row; y++)
+ page.getLine(y).cutFromBeginning(4);
+ }
+ } else {
+ // dedent current line
+ final TextLine textLine = page.getLine(cursorLocation.row);
+
+ if (cursorLocation.column >= 4)
+ if (textLine.isEmpty())
+ cursorLocation.column -= 4;
+ else if (textLine.getIndent() >= 4) {
+ cursorLocation.column -= 4;
+ textLine.cutFromBeginning(4);
+ }
+
+ }
+
+ repaintPage();
+
+ } else if (selectionStart.compareTo(selectionEnd) != 0) {
+ // indent multiple lines
+ ensureSelectionOrder();
+ for (int y = selectionStart.row; y < selectionEnd.row; y++)
+ page.getLine(y).addIndent(4);
+
+ repaintPage();
+ }
+ }
+
+ /**
+ * Repaints the entire visible page area onto the text canvas.
+ *
+ * <p>Iterates over every visible cell (row and column), applying the appropriate
+ * foreground and background colors based on whether the cell is the cursor position,
+ * part of a selection, or a tab stop margin. Characters are read from the underlying
+ * {@link Page} model with scroll offsets applied.</p>
+ */
+ public void repaintPage() {
+
+ final int columnCount = textCanvas.getSize().column + 2;
+ final int rowCount = textCanvas.getSize().row + 2;
+
+ for (int row = 0; row < rowCount; row++)
+ for (int column = 0; column < columnCount; column++) {
+ final boolean isTabMargin = ((column + scrolledCharacters) % 4) == 0;
+
+ if ((column == (cursorLocation.column - scrolledCharacters))
+ & (row == (cursorLocation.row - scrolledLines))) {
+ // cursor
+ textCanvas.setBackgroundColor(lookAndFeel.cursorBackground);
+ textCanvas.setForegroundColor(lookAndFeel.cursorForeground);
+ } else if (new TextPointer(row + scrolledLines, column).isBetween(
+ selectionStart, selectionEnd)) {
+ // selected text
+ textCanvas.setBackgroundColor(lookAndFeel.selectionBackground);
+ textCanvas.setForegroundColor(lookAndFeel.selectionForeground);
+ } else {
+ // normal text
+ textCanvas.setBackgroundColor(lookAndFeel.background);
+ textCanvas.setForegroundColor(lookAndFeel.foreground);
+
+ if (isTabMargin)
+ textCanvas
+ .setBackgroundColor(lookAndFeel.tabStopBackground);
+
+ }
+
+ final char charUnderCursor = page.getChar(row + scrolledLines,
+ column + scrolledCharacters);
+
+ textCanvas.putChar(row, column, charUnderCursor);
+ }
+
+ }
+
+ /**
+ * Repaints a single row of the editor.
+ *
+ * <p><strong>Note:</strong> the current implementation delegates to
+ * {@link #repaintPage()} and repaints the entire page. This is a candidate
+ * for optimization.</p>
+ *
+ * @param rowNumber the zero-based row index to repaint
+ */
+ public void repaintRow(final int rowNumber) {
+ // TODO: Optimize this. No need to repaint entire page.
+ repaintPage();
+ }
+
+ /**
+ * Repaints only the portions of the editor that have been marked as dirty.
+ *
+ * <p>If {@link #repaintPage} is set, the entire page is repainted and all
+ * dirty row tracking is cleared. Otherwise, only the individually dirty rows
+ * are repainted.</p>
+ */
+ private void repaintWhatNeeded() {
+ if (repaintPage) {
+ dirtyRows.clear();
+ repaintPage();
+ return;
+ }
+
+ dirtyRows.forEach(this::repaintRow);
+ dirtyRows.clear();
+ }
+
+ /**
+ * Scrolls the visible editor area by the specified number of characters and lines.
+ *
+ * <p>Scroll offsets are clamped so they never go below zero. A full page
+ * repaint is scheduled after scrolling.</p>
+ *
+ * @param charactersToScroll the number of characters to scroll horizontally
+ * (positive = right, negative = left)
+ * @param linesToScroll the number of lines to scroll vertically
+ * (positive = down, negative = up)
+ */
+ public void scroll(final int charactersToScroll, final int linesToScroll) {
+ scrolledLines += linesToScroll;
+ scrolledCharacters += charactersToScroll;
+
+ if (scrolledLines < 0)
+ scrolledLines = 0;
+
+ if (scrolledCharacters < 0)
+ scrolledCharacters = 0;
+
+ repaintPage = true;
+ }
+
+ /**
+ * Replaces the entire editor content with the given text.
+ *
+ * <p>Resets the cursor to position (0, 0), clears all scroll offsets and
+ * selections, creates a fresh {@link Page}, inserts the text, and triggers
+ * a full repaint.</p>
+ *
+ * @param text the new text content for the editor; may contain newline
+ * characters to create multiple lines
+ */
+ public void setText(final String text) {
+ // System.out.println("Set text:" + text);
+ cursorLocation = new TextPointer(0, 0);
+ scrolledCharacters = 0;
+ scrolledLines = 0;
+ selectionStart = new TextPointer(0, 0);
+ selectionEnd = new TextPointer(0, 0);
+ page = new Page();
+ insertText(text);
+ repaintPage();
+ }
+
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.gui.textEditorComponent;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Represents a single line of text in the text editor.
+ *
+ * <p>Internally stores a mutable list of {@link Character} objects, one per character in
+ * the line. Provides operations for inserting, cutting, and copying substrings, as well
+ * as indentation manipulation (adding or removing leading spaces).</p>
+ *
+ * <p>Lines automatically trim trailing whitespace via the internal {@code pack()} method,
+ * which is invoked after most mutating operations. This ensures that lines never store
+ * unnecessary trailing space characters.</p>
+ *
+ * @see Character the wrapper for individual character values in a line
+ * @see Page the container that holds multiple {@code TextLine} instances
+ * @see TextEditComponent the text editor component that uses lines for editing
+ */
+public class TextLine {
+
+ private List<Character> chars = new ArrayList<>();
+
+ /**
+ * Creates an empty text line with no characters.
+ */
+ public TextLine() {
+ }
+
+ /**
+ * Creates a text line from an existing list of {@link Character} objects.
+ *
+ * <p>Trailing whitespace is automatically trimmed via {@code pack()}.</p>
+ *
+ * @param value the list of characters to initialize this line with
+ */
+ public TextLine(final List<Character> value) {
+ chars = value;
+ pack();
+ }
+
+ /**
+ * Creates a text line initialized with the given string.
+ *
+ * <p>Each character in the string is converted to a {@link Character} object.
+ * Trailing whitespace is automatically trimmed.</p>
+ *
+ * @param value the string to initialize this line with
+ */
+ public TextLine(final String value) {
+ setValue(value);
+ }
+
+ /**
+ * Adds indentation (leading spaces) to the beginning of this line.
+ *
+ * <p>If the line is empty, no indentation is added. Otherwise, the specified
+ * number of space characters are prepended to the line.</p>
+ *
+ * @param amount the number of space characters to prepend
+ */
+ public void addIndent(final int amount) {
+ if (isEmpty())
+ return;
+
+ for (int i = 0; i < amount; i++)
+ chars.add(0, new Character(' '));
+ }
+
+ /**
+ * Removes characters from the specified range and returns them as a string.
+ *
+ * <p>This is a destructive operation: the characters in the range
+ * [{@code from}, {@code until}) are removed from this line. If the line is
+ * shorter than {@code until}, it is padded with spaces before extraction.
+ * Trailing whitespace is trimmed after removal.</p>
+ *
+ * @param from the start index (inclusive) of the range to extract
+ * @param until the end index (exclusive) of the range to extract
+ * @return the extracted characters as a string
+ */
+ public String copySubString(final int from, final int until) {
+ final StringBuilder result = new StringBuilder();
+
+ ensureLength(until);
+
+ for (int i = from; i < until; i++)
+ result.append(chars.remove(from).value);
+
+ pack();
+ return result.toString();
+ }
+
+
+ /**
+ * Removes the specified number of characters from the beginning of this line.
+ *
+ * <p>If {@code charactersToCut} exceeds the line length, the entire line is cleared.
+ * If {@code charactersToCut} is zero, no changes are made.</p>
+ *
+ * @param charactersToCut the number of leading characters to remove
+ */
+ public void cutFromBeginning(int charactersToCut) {
+
+ if (charactersToCut > chars.size())
+ charactersToCut = chars.size();
+
+ if (charactersToCut == 0)
+ return;
+
+ chars = chars.subList(charactersToCut, chars.size());
+ }
+
+ /**
+ * Extracts a substring from this line, removing those characters and returning them.
+ *
+ * <p>Characters in the range [{@code from}, {@code until}) are removed from this
+ * line and returned as a string. Characters outside the range are retained. If the
+ * line is shorter than {@code until}, it is padded with spaces before extraction.
+ * Trailing whitespace is trimmed after the cut.</p>
+ *
+ * @param from the start index (inclusive) of the range to cut
+ * @param until the end index (exclusive) of the range to cut
+ * @return the cut characters as a string
+ */
+ public String cutSubString(final int from, final int until) {
+ final StringBuilder result = new StringBuilder();
+
+ final List<Character> reminder = new ArrayList<>();
+
+ ensureLength(until);
+
+ for (int i = 0; i < chars.size(); i++)
+ if ((i >= from) && (i < until))
+ result.append(chars.get(i).value);
+ else
+ reminder.add(chars.get(i));
+
+ chars = reminder;
+
+ pack();
+ return result.toString();
+ }
+
+ /**
+ * Truncates this line at the specified column, discarding all characters from
+ * that position to the end.
+ *
+ * <p>If {@code col} is greater than or equal to the current line length,
+ * no changes are made.</p>
+ *
+ * @param col the column index at which to truncate (exclusive; characters at
+ * indices 0 through {@code col - 1} are kept)
+ */
+ public void cutUntilEnd(final int col) {
+ if (col >= chars.size())
+ return;
+
+ chars = chars.subList(0, col);
+ }
+
+ /**
+ * Ensures the internal character list is at least the given length,
+ * padding with space characters as needed.
+ */
+ private void ensureLength(final int length) {
+ while (chars.size() < length)
+ chars.add(new Character(' '));
+ }
+
+ /**
+ * Returns the character at the specified column position.
+ *
+ * <p>If the column is beyond the end of this line, a space character is returned.</p>
+ *
+ * @param col the zero-based column index
+ * @return the character at the given column, or {@code ' '} if out of bounds
+ */
+ public char getCharForLocation(final int col) {
+
+ if (col >= chars.size())
+ return ' ';
+
+ return chars.get(col).value;
+ }
+
+ /**
+ * Returns the internal list of {@link Character} objects backing this line.
+ *
+ * <p><strong>Note:</strong> the returned list is the live internal list. Modifications
+ * to the returned list will directly affect this line.</p>
+ *
+ * @return the mutable list of characters in this line
+ */
+ public List<Character> getChars() {
+ return chars;
+ }
+
+ /**
+ * Returns the indentation level of this line, measured as the number of
+ * leading space characters before the first non-space character.
+ *
+ * <p>If the line is empty, returns {@code 0}.</p>
+ *
+ * @return the number of leading space characters
+ * @throws RuntimeException if the line is non-empty but contains only spaces
+ * (should not occur due to trailing whitespace trimming by {@code pack()})
+ */
+ public int getIndent() {
+ if (isEmpty())
+ return 0;
+
+ for (int i = 0; i < chars.size(); i++)
+ if (chars.get(i).hasValue())
+ return i;
+
+ throw new RuntimeException("This code shall never execute");
+ }
+
+ /**
+ * Returns the length of this line (number of characters, excluding trimmed
+ * trailing whitespace).
+ *
+ * @return the number of characters in this line
+ */
+ public int getLength() {
+ return chars.size();
+ }
+
+ /**
+ * Returns a new {@code TextLine} containing the characters from this line
+ * in the range [{@code from}, {@code until}).
+ *
+ * <p>If {@code until} exceeds the line length, only the available characters
+ * are included. The returned line is an independent copy.</p>
+ *
+ * @param from the start index (inclusive)
+ * @param until the end index (exclusive)
+ * @return a new {@code TextLine} with the specified sub-range of characters
+ */
+ public TextLine getSubLine(final int from, final int until) {
+ final List<Character> result = new ArrayList<>();
+
+ for (int i = from; i < until; i++) {
+ if (i >= chars.size())
+ break;
+ result.add(chars.get(i));
+ }
+
+ return new TextLine(result);
+ }
+
+ /**
+ * Returns a substring of this line from column {@code from} (inclusive) to
+ * column {@code until} (exclusive).
+ *
+ * <p>If the requested range extends beyond the line length, space characters
+ * are used for positions past the end of the line.</p>
+ *
+ * @param from the start column (inclusive)
+ * @param until the end column (exclusive)
+ * @return the substring in the specified range
+ */
+ public String getSubString(final int from, final int until) {
+ final StringBuilder result = new StringBuilder();
+
+ for (int i = from; i < until; i++)
+ result.append(getCharForLocation(i));
+
+ return result.toString();
+ }
+
+ /**
+ * Inserts a single character at the specified column position.
+ *
+ * <p>If the column is beyond the current line length, the line is padded
+ * with spaces up to that position. Trailing whitespace is trimmed after
+ * insertion.</p>
+ *
+ * @param col the zero-based column at which to insert
+ * @param value the character to insert
+ */
+ public void insertCharacter(final int col, final char value) {
+ ensureLength(col);
+ chars.add(col, new Character(value));
+ pack();
+ }
+
+ /**
+ * Inserts a string at the specified column position.
+ *
+ * <p>Each character in the string is inserted sequentially starting at
+ * {@code col}. If the column is beyond the current line length, the line
+ * is padded with spaces. Trailing whitespace is trimmed after insertion.</p>
+ *
+ * @param col the zero-based column at which to start inserting
+ * @param value the string to insert
+ */
+ public void insertString(final int col, final String value) {
+ ensureLength(col);
+ int i = 0;
+ for (final char c : value.toCharArray()) {
+ chars.add(col + i, new Character(c));
+ i++;
+ }
+ pack();
+ }
+
+ /**
+ * Inserts all characters from another {@code TextLine} at the specified column.
+ *
+ * <p>If the column is beyond the current line length, the line is padded with
+ * spaces. Trailing whitespace is trimmed after insertion.</p>
+ *
+ * @param col the zero-based column at which to start inserting
+ * @param textLine the text line whose characters will be inserted
+ */
+ public void insertTextLine(final int col, final TextLine textLine) {
+ ensureLength(col);
+ int i = 0;
+ for (final Character c : textLine.getChars()) {
+ chars.add(col + i, c);
+ i++;
+ }
+ pack();
+ }
+
+ /**
+ * Returns whether this line contains no characters.
+ *
+ * <p>Because trailing whitespace is trimmed, an empty line means there are
+ * no visible characters on this line.</p>
+ *
+ * @return {@code true} if the line has no characters, {@code false} otherwise
+ */
+ public boolean isEmpty() {
+ return chars.isEmpty();
+ }
+
+ /**
+ * Trims trailing whitespace from this line by removing trailing space
+ * characters that have no visible content.
+ */
+ private void pack() {
+ int newLength = 0;
+
+ for (int i = chars.size() - 1; i >= 0; i--)
+ if (chars.get(i).hasValue()) {
+ newLength = i + 1;
+ break;
+ }
+
+ if (newLength == chars.size())
+ return;
+
+ chars = chars.subList(0, newLength);
+ }
+
+ /**
+ * Removes the character at the specified column position.
+ *
+ * <p>If the column is beyond the end of the line, no changes are made.</p>
+ *
+ * @param col the zero-based column of the character to remove
+ */
+ public void removeCharacter(final int col) {
+ if (col >= chars.size())
+ return;
+
+ chars.remove(col);
+ }
+
+ /**
+ * Replaces the entire contents of this line with the given string.
+ *
+ * <p>The existing characters are cleared, and each character from the string
+ * is added as a new {@link Character} object. Trailing whitespace is trimmed.</p>
+ *
+ * @param string the new text content for this line
+ */
+ public void setValue(final String string) {
+ chars.clear();
+ for (final char c : string.toCharArray())
+ chars.add(new Character(c));
+
+ pack();
+ }
+
+ /**
+ * Returns the string representation of this line by concatenating
+ * all character values.
+ *
+ * @return the text content of this line as a {@code String}
+ */
+ @Override
+ public String toString() {
+ final StringBuilder buffer = new StringBuilder();
+
+ for (final Character character : chars)
+ buffer.append(character.value);
+
+ return buffer.toString();
+ }
+
+}
--- /dev/null
+/**
+ * Provides a simple text editor component rendered in 3D space.
+ *
+ * @see eu.svjatoslav.aukio.e3d.gui.textEditorComponent.TextEditComponent
+ */
+package eu.svjatoslav.aukio.e3d.gui.textEditorComponent;
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.headless;
+
+import javax.imageio.ImageIO;
+import java.awt.image.BufferedImage;
+import java.io.File;
+import java.io.IOException;
+import java.util.Locale;
+
+/**
+ * Golden-image comparison: render a scene, compare against a committed
+ * reference PNG, fail when the picture drifts.
+ *
+ * <p>A pixel counts as different when any RGB channel differs by more than
+ * a per-channel tolerance; a comparison fails when the fraction of
+ * differing pixels exceeds a threshold. Both are parameters — shading and
+ * antialiasing make exact matches fragile, but "the floor lost 30% of its
+ * pixels" must not pass.</p>
+ *
+ * <p><b>Example:</b></p>
+ * <pre>{@code
+ * BufferedImage actual = Snapshot.render(scene, lighting, pose, 640, 480);
+ * GoldenImage.Result r = GoldenImage.compare(actual, new File("goldens/house.png"), 8, 0.01);
+ * if (!r.passed) {
+ * GoldenImage.saveDiff(actual, new File("goldens/house.png"), "/tmp/diff.png");
+ * throw new AssertionError(r.toString());
+ * }
+ * }</pre>
+ *
+ * <p>Command line (for scripts):</p>
+ * <pre>
+ * java eu.svjatoslav.aukio.e3d.headless.GoldenImage actual.png golden.png [tolerance] [maxDiffFraction]
+ * exit code 0 = match, 1 = differ, 2 = usage/io error
+ * </pre>
+ *
+ * @see Snapshot
+ */
+public final class GoldenImage {
+
+ private GoldenImage() {
+ // utility class
+ }
+
+ /** Outcome of one comparison. */
+ public static final class Result {
+ /** True when the images match within tolerance. */
+ public final boolean passed;
+ /** Fraction of pixels that differ (0..1). */
+ public final double diffFraction;
+ /** Absolute count of differing pixels. */
+ public final int diffPixels;
+ /** Total pixels compared. */
+ public final int totalPixels;
+
+ Result(final boolean passed, final double diffFraction,
+ final int diffPixels, final int totalPixels) {
+ this.passed = passed;
+ this.diffFraction = diffFraction;
+ this.diffPixels = diffPixels;
+ this.totalPixels = totalPixels;
+ }
+
+ @Override
+ public String toString() {
+ return String.format(Locale.ROOT, "%s: %d/%d pixels differ (%.4f)",
+ passed ? "PASS" : "FAIL", diffPixels, totalPixels, diffFraction);
+ }
+ }
+
+ /**
+ * Compares an image against a golden PNG file.
+ *
+ * @param actual the rendered image
+ * @param goldenFile the reference PNG
+ * @param channelTolerance per-channel (R/G/B) tolerance, 0 = exact
+ * @param maxDiffFraction maximum allowed fraction of differing pixels (0..1)
+ * @return the comparison result
+ * @throws IOException on read failure or size mismatch
+ */
+ public static Result compare(final BufferedImage actual, final File goldenFile,
+ final int channelTolerance, final double maxDiffFraction)
+ throws IOException {
+ final BufferedImage golden = ImageIO.read(goldenFile);
+ if (golden == null)
+ throw new IOException("cannot read golden image: " + goldenFile);
+ if (golden.getWidth() != actual.getWidth() || golden.getHeight() != actual.getHeight())
+ throw new IOException("size mismatch: actual " + actual.getWidth() + "x" + actual.getHeight()
+ + " vs golden " + golden.getWidth() + "x" + golden.getHeight());
+
+ int diff = 0;
+ final int width = actual.getWidth();
+ final int height = actual.getHeight();
+ for (int y = 0; y < height; y++) {
+ for (int x = 0; x < width; x++) {
+ if (differs(actual.getRGB(x, y), golden.getRGB(x, y), channelTolerance))
+ diff++;
+ }
+ }
+ final int total = width * height;
+ final double fraction = (double) diff / total;
+ return new Result(fraction <= maxDiffFraction, fraction, diff, total);
+ }
+
+ /**
+ * Writes a visual diff image: matching pixels dimmed, differing pixels
+ * highlighted red. Handy for inspecting a failed comparison.
+ *
+ * @param actual the rendered image
+ * @param goldenFile the reference PNG
+ * @param outPath where to write the diff PNG
+ * @throws IOException on read/write failure or size mismatch
+ */
+ public static void saveDiff(final BufferedImage actual, final File goldenFile,
+ final String outPath) throws IOException {
+ final BufferedImage golden = ImageIO.read(goldenFile);
+ final BufferedImage diff = new BufferedImage(actual.getWidth(), actual.getHeight(),
+ BufferedImage.TYPE_INT_RGB);
+ for (int y = 0; y < actual.getHeight(); y++) {
+ for (int x = 0; x < actual.getWidth(); x++) {
+ final int a = actual.getRGB(x, y);
+ if (differs(a, golden.getRGB(x, y), 0)) {
+ diff.setRGB(x, y, 0xFF0000);
+ } else {
+ // dimmed original: quarter brightness
+ diff.setRGB(x, y, ((a >> 2) & 0x3F3F3F));
+ }
+ }
+ }
+ ImageIO.write(diff, "png", new File(outPath));
+ }
+
+ /** True when any channel of the two RGB values differs by more than tolerance. */
+ private static boolean differs(final int rgb1, final int rgb2, final int tolerance) {
+ for (int shift = 16; shift >= 0; shift -= 8) {
+ final int c1 = (rgb1 >> shift) & 0xFF;
+ final int c2 = (rgb2 >> shift) & 0xFF;
+ if (Math.abs(c1 - c2) > tolerance)
+ return true;
+ }
+ return false;
+ }
+
+ /**
+ * CLI: compares two PNGs. Exit 0 = match, 1 = differ, 2 = error.
+ *
+ * @param args actual.png golden.png [channelTolerance] [maxDiffFraction]
+ */
+ public static void main(final String[] args) {
+ if (args.length < 2) {
+ System.err.println("usage: GoldenImage actual.png golden.png [channelTolerance] [maxDiffFraction]");
+ System.exit(2);
+ }
+ try {
+ final int tolerance = args.length > 2 ? Integer.parseInt(args[2]) : 0;
+ final double maxFraction = args.length > 3 ? Double.parseDouble(args[3]) : 0.0;
+ final BufferedImage actual = ImageIO.read(new File(args[0]));
+ final Result result = compare(actual, new File(args[1]), tolerance, maxFraction);
+ System.out.println(result);
+ System.exit(result.passed ? 0 : 1);
+ } catch (final Exception e) {
+ System.err.println("error: " + e.getMessage());
+ System.exit(2);
+ }
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.headless;
+
+import java.awt.image.BufferedImage;
+
+/**
+ * Pixel-level assertions for headless render verification.
+ *
+ * <p>The recurring question in rasterizer debugging is "did this region of
+ * the screen actually get painted?" These helpers answer it against a
+ * {@link BufferedImage} produced by {@link Snapshot}, treating one chosen
+ * background color as "unpainted". All methods are static and return data
+ * rather than throwing, so callers decide how to report failures.</p>
+ *
+ * <p><b>Example — assert the floor rendered (no holes from clipping):</b></p>
+ * <pre>{@code
+ * BufferedImage image = Snapshot.render(scene, lighting, pose, 640, 480);
+ * double holes = PixelAssertions.unpaintedFraction(image, 0x00000000,
+ * 0.15, 0.45, 0.85, 1.0); // lower-center band
+ * if (holes > 0.05)
+ * throw new AssertionError("floor has holes: " + holes);
+ * }</pre>
+ *
+ * @see Snapshot
+ * @see GoldenImage
+ */
+public final class PixelAssertions {
+
+ private PixelAssertions() {
+ // utility class
+ }
+
+ /**
+ * Fraction of pixels in the whole image that still equal the background
+ * color (i.e. nothing was painted there).
+ *
+ * @param image the rendered image
+ * @param backgroundRgb the background color (RGB, alpha ignored)
+ * @return fraction in [0, 1]
+ */
+ public static double unpaintedFraction(final BufferedImage image, final int backgroundRgb) {
+ return unpaintedFraction(image, backgroundRgb, 0, 0, 1, 1);
+ }
+
+ /**
+ * Fraction of pixels inside a relative rectangle that still equal the
+ * background color.
+ *
+ * @param image the rendered image
+ * @param backgroundRgb the background color (RGB, alpha ignored)
+ * @param x0 left edge, fraction of width (0..1)
+ * @param y0 top edge, fraction of height (0..1)
+ * @param x1 right edge, fraction of width (0..1)
+ * @param y1 bottom edge, fraction of height (0..1)
+ * @return fraction in [0, 1]
+ */
+ public static double unpaintedFraction(final BufferedImage image, final int backgroundRgb,
+ final double x0, final double y0,
+ final double x1, final double y1) {
+ final int width = image.getWidth();
+ final int height = image.getHeight();
+ final int bg = backgroundRgb & 0xFFFFFF;
+
+ int total = 0;
+ int unpainted = 0;
+ for (int y = (int) (height * y0); y < (int) (height * y1); y++) {
+ for (int x = (int) (width * x0); x < (int) (width * x1); x++) {
+ total++;
+ if ((image.getRGB(x, y) & 0xFFFFFF) == bg)
+ unpainted++;
+ }
+ }
+ return total == 0 ? 0 : (double) unpainted / total;
+ }
+
+ /**
+ * Counts pixels in the whole image that differ from the background color.
+ *
+ * @param image the rendered image
+ * @param backgroundRgb the background color (RGB, alpha ignored)
+ * @return number of painted pixels
+ */
+ public static long countPainted(final BufferedImage image, final int backgroundRgb) {
+ final int bg = backgroundRgb & 0xFFFFFF;
+ long painted = 0;
+ for (int y = 0; y < image.getHeight(); y++)
+ for (int x = 0; x < image.getWidth(); x++)
+ if ((image.getRGB(x, y) & 0xFFFFFF) != bg)
+ painted++;
+ return painted;
+ }
+
+ /**
+ * Counts pixels equal (in RGB) to the given color. Useful with flat
+ * test colors: "how much of the red triangle made it to the screen?"
+ *
+ * @param image the rendered image
+ * @param rgb the color to count (alpha ignored)
+ * @return number of matching pixels
+ */
+ public static long countColor(final BufferedImage image, final int rgb) {
+ final int wanted = rgb & 0xFFFFFF;
+ long count = 0;
+ for (int y = 0; y < image.getHeight(); y++)
+ for (int x = 0; x < image.getWidth(); x++)
+ if ((image.getRGB(x, y) & 0xFFFFFF) == wanted)
+ count++;
+ return count;
+ }
+
+ /**
+ * Dumps a grid of pixel colors around a point as text, for eyeballing
+ * gradients/edges in a failing render. Samples every {@code stride}
+ * pixels, formatted as RRGGBB hex, one row per line.
+ *
+ * @param image the rendered image
+ * @param cx center X in pixels
+ * @param cy center Y in pixels
+ * @param radius grid extends this many samples in each direction
+ * @param stride pixels between samples
+ * @return multi-line hex grid string
+ */
+ public static String dumpPixelGrid(final BufferedImage image,
+ final int cx, final int cy,
+ final int radius, final int stride) {
+ final StringBuilder sb = new StringBuilder();
+ for (int dy = -radius; dy <= radius; dy++) {
+ for (int dx = -radius; dx <= radius; dx++) {
+ final int x = cx + dx * stride;
+ final int y = cy + dy * stride;
+ if (x < 0 || y < 0 || x >= image.getWidth() || y >= image.getHeight()) {
+ sb.append(" ---- ");
+ } else {
+ sb.append(String.format("%06X", image.getRGB(x, y) & 0xFFFFFF));
+ }
+ if (dx < radius)
+ sb.append(' ');
+ }
+ sb.append('\n');
+ }
+ return sb.toString();
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.headless;
+
+import eu.svjatoslav.aukio.e3d.renderer.raster.gi.GlobalIllumination;
+import eu.svjatoslav.aukio.e3d.renderer.raster.lighting.LightSource;
+import eu.svjatoslav.aukio.e3d.renderer.raster.lighting.LightingManager;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.AbstractShape;
+import eu.svjatoslav.aukio.e3d.renderer.raster.ShapeCollection;
+import eu.svjatoslav.aukio.e3d.geometry.Camera;
+
+import java.util.Locale;
+
+/**
+ * Text dump of everything that determines what a frame looks like: shape
+ * counts, lights, camera pose, GI status. One call, one string — paste it
+ * into a bug report and the scene is reproducible.
+ *
+ * <p><b>Example:</b></p>
+ * <pre>{@code
+ * System.out.println(SceneDump.dump(scene, lighting, camera, gi));
+ * }</pre>
+ *
+ * <p>Sample output:</p>
+ * <pre>
+ * == SceneDump ==
+ * shapes: 214 top-level, 1892 queued for rendering
+ * lights: 4 (ambient #181818)
+ * [0] pos=(-800.0, -240.0, 0.0) color=FFD890 intensity=6.0
+ * ...
+ * camera: 290.31, -35.59, -2.10, -0.58, -0.15, -0.00
+ * GI: running, 152034 work items, converged
+ * </pre>
+ *
+ * @see Snapshot#poseString(Camera)
+ */
+public final class SceneDump {
+
+ private SceneDump() {
+ // utility class
+ }
+
+ /**
+ * Dumps scene state to a human-readable string.
+ *
+ * @param scene the scene (may be null to skip shape counts)
+ * @param lighting the lighting manager (may be null to skip lights)
+ * @param camera the camera (may be null to skip the pose)
+ * @param gi the GI system, or null when GI is not in use
+ * @return the dump, one fact per line
+ */
+ public static String dump(final ShapeCollection scene,
+ final LightingManager lighting,
+ final Camera camera,
+ final GlobalIllumination gi) {
+ final StringBuilder sb = new StringBuilder("== SceneDump ==\n");
+
+ if (scene != null) {
+ int topLevel = 0;
+ for (final AbstractShape ignored : scene.getShapes())
+ topLevel++;
+ sb.append("shapes: ").append(topLevel)
+ .append(" top-level, ").append(scene.getQueuedShapeCount())
+ .append(" queued for rendering\n");
+ }
+
+ if (lighting != null) {
+ sb.append("lights: ").append(lighting.getLights().size())
+ .append(" (ambient #")
+ .append(String.format("%06X", rgbOf(lighting.getAmbientLight())))
+ .append(")\n");
+ int i = 0;
+ for (final LightSource light : lighting.getLights()) {
+ sb.append(String.format(Locale.ROOT,
+ " [%d] pos=(%.1f, %.1f, %.1f) color=%06X intensity=%.1f%n",
+ i++, light.getPosition().x, light.getPosition().y, light.getPosition().z,
+ rgbOf(light.getColor()), light.getIntensity()));
+ }
+ }
+
+ if (camera != null)
+ sb.append("camera: ").append(Snapshot.poseString(camera)).append('\n');
+
+ if (gi != null) {
+ sb.append("GI: ");
+ if (!gi.isRunning()) {
+ sb.append("stopped\n");
+ } else {
+ sb.append("running, ").append(gi.getWorkItemCount()).append(" work items, ")
+ .append(gi.isConverged() ? "converged" : "converging").append('\n');
+ }
+ }
+
+ return sb.toString();
+ }
+
+ /** Packs an engine Color's r/g/b fields into a 0xRRGGBB int. */
+ private static int rgbOf(final eu.svjatoslav.aukio.e3d.renderer.raster.Color color) {
+ return ((color.r & 0xFF) << 16) | ((color.g & 0xFF) << 8) | (color.b & 0xFF);
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.headless;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.geometry.Camera;
+import eu.svjatoslav.aukio.e3d.renderer.raster.RenderingContext;
+import eu.svjatoslav.aukio.e3d.renderer.raster.ShapeCollection;
+import eu.svjatoslav.aukio.e3d.renderer.raster.lighting.LightingManager;
+
+import javax.imageio.ImageIO;
+import java.awt.image.BufferedImage;
+import java.io.File;
+import java.io.IOException;
+import java.util.Arrays;
+
+/**
+ * One-call facade for rendering a scene to an image without a window.
+ *
+ * <p>Assembles the same transform → sort → paint pipeline that
+ * {@code ViewPanel} drives on screen, but into an off-screen
+ * {@link RenderingContext} pixel buffer. No Swing frame, no X display, no
+ * render thread — safe to use from tests, doc tooling and batch jobs.</p>
+ *
+ * <p><b>Example:</b></p>
+ * <pre>{@code
+ * ShapeCollection scene = new ShapeCollection();
+ * scene.addShape(myShape);
+ *
+ * LightingManager lighting = new LightingManager();
+ * lighting.setAmbientLight(Color.hex("181818"));
+ *
+ * BufferedImage image = Snapshot.render(scene, lighting,
+ * "290.31, -35.59, -2.10, -0.58, -0.15, 0.0", 640, 480);
+ * Snapshot.save(image, "/tmp/snapshot.png");
+ * }</pre>
+ *
+ * <p>The pose string is the same "x, y, z, yaw, pitch, roll" format the
+ * demos print for camera positions, so a pose copy-pasted from a bug
+ * report reproduces the exact view.</p>
+ *
+ * @see PixelAssertions for checking what got painted
+ * @see GoldenImage for comparing against a reference PNG
+ * @see SceneDump for inspecting the scene state behind an image
+ */
+public final class Snapshot {
+
+ private Snapshot() {
+ // utility class
+ }
+
+ /**
+ * Renders the scene once from the given pose string.
+ *
+ * @param scene the scene to render
+ * @param lighting lighting for the frame (may be null for unlit scenes)
+ * @param pose "x, y, z, yaw, pitch, roll" — same format demos print
+ * @param width image width in pixels
+ * @param height image height in pixels
+ * @return the rendered frame (background is black)
+ */
+ public static BufferedImage render(final ShapeCollection scene,
+ final LightingManager lighting,
+ final String pose,
+ final int width, final int height) {
+ return render(scene, lighting, cameraFromPose(pose), width, height);
+ }
+
+ /**
+ * Renders the scene once from the given camera.
+ *
+ * @param scene the scene to render
+ * @param lighting lighting for the frame (may be null for unlit scenes)
+ * @param camera positioned camera
+ * @param width image width in pixels
+ * @param height image height in pixels
+ * @return the rendered frame (background is black)
+ */
+ public static BufferedImage render(final ShapeCollection scene,
+ final LightingManager lighting,
+ final Camera camera,
+ final int width, final int height) {
+ final RenderingContext ctx = new RenderingContext(width, height, 1);
+ ctx.lightingManager = lighting;
+ renderInto(scene, camera, ctx, 0);
+ return ctx.getImage();
+ }
+
+ /**
+ * Renders one frame into an existing context, filling the background
+ * with the given ARGB color first. Use a unique sentinel color when the
+ * caller needs to distinguish "nothing painted here" from "painted
+ * black" (e.g. hole detection in clipping tests).
+ *
+ * @param scene the scene to render
+ * @param camera positioned camera
+ * @param ctx target context (its {@code pixels} buffer is painted)
+ * @param backgroundArgb background fill applied before painting
+ */
+ public static void renderInto(final ShapeCollection scene,
+ final Camera camera,
+ final RenderingContext ctx,
+ final int backgroundArgb) {
+ final Point3D location = camera.getTransform().getTranslation();
+ ctx.viewerPosition.x = location.x;
+ ctx.viewerPosition.y = location.y;
+ ctx.viewerPosition.z = location.z;
+
+ Arrays.fill(ctx.pixels, backgroundArgb);
+ Arrays.fill(ctx.depth, Float.NEGATIVE_INFINITY);
+ scene.transformShapes(camera, ctx);
+ scene.sortShapes(ctx.vertexSlot);
+ scene.paintShapes(ctx);
+ if (System.getProperty("aukio.zbuffer.dumpDepth") != null)
+ dumpDepth(ctx, System.getProperty("aukio.zbuffer.dumpDepth"));
+ ctx.frameNumber++;
+ }
+
+ /**
+ * Debug helper: saves the depth buffer as a grayscale PNG (z = 1/w,
+ * log-scaled; untouched pixels black). Enabled per render via
+ * {@code -Daukio.zbuffer.dumpDepth=/path.png}.
+ */
+ private static void dumpDepth(final RenderingContext ctx,
+ final String path) {
+ final int w = ctx.width;
+ final int h = ctx.height;
+ final BufferedImage img = new BufferedImage(w, h,
+ BufferedImage.TYPE_BYTE_GRAY);
+ final byte[] out = ((java.awt.image.DataBufferByte)
+ img.getRaster().getDataBuffer()).getData();
+ double maxLog = 1;
+ for (int i = 0; i < w * h; i++) {
+ final float dw = ctx.depth[i];
+ if (dw > 0)
+ maxLog = Math.max(maxLog, Math.log(1d / dw));
+ }
+ for (int i = 0; i < w * h; i++) {
+ final float dw = ctx.depth[i];
+ if (dw > 0) {
+ final double z = 1d / dw;
+ out[i] = (byte) (255 * Math.log(z) / maxLog);
+ }
+ }
+ try {
+ javax.imageio.ImageIO.write(img, "png",
+ new java.io.File(path));
+ } catch (final java.io.IOException e) {
+ System.out.println("depth dump failed: " + e.getMessage());
+ }
+ }
+
+ /**
+ * Builds a camera from a "x, y, z, yaw, pitch, roll" pose string, as
+ * printed by demos (see {@link #poseString(Camera)}).
+ *
+ * @param pose the pose string; commas and extra whitespace tolerated
+ * @return a camera at that pose
+ */
+ public static Camera cameraFromPose(final String pose) {
+ final String[] parts = pose.split(",");
+ if (parts.length != 6)
+ throw new IllegalArgumentException(
+ "pose must have 6 comma-separated values (x, y, z, yaw, pitch, roll), got: " + pose);
+ final double[] v = new double[6];
+ for (int i = 0; i < 6; i++)
+ v[i] = Double.parseDouble(parts[i].trim());
+ final Camera camera = new Camera();
+ camera.getTransform().set(v[0], v[1], v[2], v[3], v[4], v[5]);
+ return camera;
+ }
+
+ /**
+ * Formats a camera's pose as "x, y, z, yaw, pitch, roll" — the exact
+ * string {@link #cameraFromPose(String)} parses back. Intended for bug
+ * reports: paste the pose, reproduce the view.
+ *
+ * @param camera the camera to describe
+ * @return the pose string
+ */
+ public static String poseString(final Camera camera) {
+ final Point3D p = camera.getTransform().getTranslation();
+ final double[] angles = camera.getTransform().getRotation().toAngles();
+ return String.format(java.util.Locale.ROOT, "%.2f, %.2f, %.2f, %.2f, %.2f, %.2f",
+ p.x, p.y, p.z, angles[0], angles[1], angles[2]);
+ }
+
+ /**
+ * Saves an image as PNG.
+ *
+ * @param image the image to save
+ * @param path target file path
+ * @throws IOException on write failure
+ */
+ public static void save(final BufferedImage image, final String path) throws IOException {
+ ImageIO.write(image, "png", new File(path));
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+
+/**
+ * Headless rendering toolkit: windowless snapshots, pixel assertions,
+ * golden-image comparison and scene-state dumps.
+ *
+ * <p>Everything here works without a display, a Swing frame or a render
+ * thread, driving the same transform/sort/paint pipeline the on-screen
+ * path uses. Built for automated verification (tests, doc tooling, AI
+ * agents), but equally useful for batch thumbnail generation.</p>
+ *
+ * <ul>
+ * <li>{@link eu.svjatoslav.aukio.e3d.headless.Snapshot} — render a scene to a BufferedImage; pose strings</li>
+ * <li>{@link eu.svjatoslav.aukio.e3d.headless.PixelAssertions} — "did this region get painted?"</li>
+ * <li>{@link eu.svjatoslav.aukio.e3d.headless.GoldenImage} — compare against a reference PNG</li>
+ * <li>{@link eu.svjatoslav.aukio.e3d.headless.SceneDump} — shapes/lights/camera/GI state as text</li>
+ * </ul>
+ */
+package eu.svjatoslav.aukio.e3d.headless;
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+
+package eu.svjatoslav.aukio.e3d.math;
+
+import java.util.Random;
+
+/**
+ * Diamond-square algorithm for procedural noise generation.
+ * <p>
+ * Generates realistic fractal noise suitable for terrain, textures,
+ * and other procedural content. The algorithm produces a 2D map
+ * where each value falls within the specified [min, max] range.
+ * <p>
+ * Grid size must be 2^n + 1 (e.g., 3, 5, 9, 17, 33, 65, 129, 257).
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Diamond-square_algorithm">Diamond-square algorithm</a>
+ */
+public final class DiamondSquare {
+
+ private static final double DEFAULT_ROUGHNESS = 0.6;
+
+ private DiamondSquare() {
+ }
+
+ /**
+ * Generates a fractal noise map using the diamond-square algorithm.
+ *
+ * @param gridSize the size of the grid (must be 2^n + 1)
+ * @param min the minimum value in the output
+ * @param max the maximum value in the output
+ * @param seed random seed for reproducible results
+ * @return a 2D array of values in range [min, max]
+ * @throws IllegalArgumentException if gridSize is not 2^n + 1
+ */
+ public static double[][] generateMap(int gridSize, double min, double max, long seed) {
+ return generateMap(gridSize, min, max, DEFAULT_ROUGHNESS, seed);
+ }
+
+ /**
+ * Generates a fractal noise map using the diamond-square algorithm with custom roughness.
+ *
+ * @param gridSize the size of the grid (must be 2^n + 1)
+ * @param min the minimum value in the output
+ * @param max the maximum value in the output
+ * @param roughness the roughness factor (0.0 to 1.0), higher values produce more variation
+ * @param seed random seed for reproducible results
+ * @return a 2D array of values in range [min, max]
+ * @throws IllegalArgumentException if gridSize is not 2^n + 1
+ */
+ public static double[][] generateMap(int gridSize, double min, double max, double roughness, long seed) {
+ if (!isValidGridSize(gridSize)) {
+ throw new IllegalArgumentException("Grid size must be 2^n + 1 (e.g., 65, 129, 257)");
+ }
+
+ Random random = new Random(seed);
+ double[][] map = new double[gridSize][gridSize];
+
+ map[0][0] = random.nextDouble();
+ map[0][gridSize - 1] = random.nextDouble();
+ map[gridSize - 1][0] = random.nextDouble();
+ map[gridSize - 1][gridSize - 1] = random.nextDouble();
+
+ int stepSize = gridSize - 1;
+ double currentScale = roughness;
+
+ while (stepSize > 1) {
+ int halfStep = stepSize / 2;
+
+ for (int y = 0; y < gridSize - 1; y += stepSize) {
+ for (int x = 0; x < gridSize - 1; x += stepSize) {
+ double avg = (map[y][x] +
+ map[y][x + stepSize] +
+ map[y + stepSize][x] +
+ map[y + stepSize][x + stepSize]) / 4.0;
+ map[y + halfStep][x + halfStep] =
+ avg + (random.nextDouble() - 0.5) * currentScale;
+ }
+ }
+
+ for (int y = 0; y < gridSize; y += stepSize) {
+ for (int x = 0; x < gridSize; x += stepSize) {
+ if (x + halfStep < gridSize) {
+ double avg = map[y][x];
+ if (x - halfStep >= 0) {
+ avg += map[y][x - halfStep];
+ }
+ if (x + stepSize < gridSize) {
+ avg += map[y][x + stepSize];
+ }
+ if (y + halfStep < gridSize) {
+ avg += map[y + halfStep][x + halfStep];
+ } else if (y - halfStep >= 0) {
+ avg += map[y - halfStep][x + halfStep];
+ }
+ map[y][x + halfStep] =
+ avg / 4.0 + (random.nextDouble() - 0.5) * currentScale;
+ }
+
+ if (y + halfStep < gridSize) {
+ double avg = map[y][x];
+ if (y - halfStep >= 0) {
+ avg += map[y - halfStep][x];
+ }
+ if (y + stepSize < gridSize) {
+ avg += map[y + stepSize][x];
+ }
+ if (x + halfStep < gridSize) {
+ avg += map[y + halfStep][x + halfStep];
+ } else if (x - halfStep >= 0) {
+ avg += map[y + halfStep][x - halfStep];
+ }
+ map[y + halfStep][x] =
+ avg / 4.0 + (random.nextDouble() - 0.5) * currentScale;
+ }
+ }
+ }
+
+ stepSize = halfStep;
+ currentScale *= roughness;
+ }
+
+ normalize(map, min, max);
+ return map;
+ }
+
+ private static void normalize(double[][] map, double min, double max) {
+ double actualMin = Double.MAX_VALUE;
+ double actualMax = Double.MIN_VALUE;
+
+ for (double[] row : map) {
+ for (double value : row) {
+ if (value < actualMin) actualMin = value;
+ if (value > actualMax) actualMax = value;
+ }
+ }
+
+ double range = actualMax - actualMin;
+ double targetRange = max - min;
+
+ if (range == 0) {
+ for (int y = 0; y < map.length; y++) {
+ for (int x = 0; x < map[y].length; x++) {
+ map[y][x] = min;
+ }
+ }
+ return;
+ }
+
+ for (int y = 0; y < map.length; y++) {
+ for (int x = 0; x < map[y].length; x++) {
+ map[y][x] = min + (map[y][x] - actualMin) / range * targetRange;
+ }
+ }
+ }
+
+ /**
+ * Checks if the grid size is valid for the diamond-square algorithm.
+ * Valid sizes are 2^n + 1 (e.g., 3, 5, 9, 17, 33, 65, 129, 257).
+ *
+ * @param size the grid size to validate
+ * @return true if the size is valid
+ */
+ public static boolean isValidGridSize(int size) {
+ if (size < 3) return false;
+ int value = size - 1;
+ return (value & (value - 1)) == 0;
+ }
+}
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.math;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+
+/**
+ * A 3x3 matrix for 3D transformations.
+ *
+ * <p>Matrix elements are stored in row-major order:</p>
+ * <pre>
+ * | m00 m01 m02 |
+ * | m10 m11 m12 |
+ * | m20 m21 m22 |
+ * </pre>
+ *
+ * @see Point3D
+ */
+public class Matrix3x3 {
+
+ public double m00;
+ public double m01;
+ public double m02;
+ public double m10;
+ public double m11;
+ public double m12;
+ public double m20;
+ public double m21;
+ public double m22;
+
+ /**
+ * Creates a zero matrix.
+ */
+ public Matrix3x3() {
+ }
+
+ /**
+ * Returns an identity matrix.
+ *
+ * @return a new identity matrix
+ */
+ public static Matrix3x3 identity() {
+ final Matrix3x3 m = new Matrix3x3();
+ m.m00 = 1;
+ m.m11 = 1;
+ m.m22 = 1;
+ return m;
+ }
+
+ /**
+ * Applies this matrix transformation to a point.
+ *
+ * @param in the input point (not modified)
+ * @param out the output point (will be modified)
+ */
+ public void transform(final Point3D in, final Point3D out) {
+ final double x = m00 * in.x + m01 * in.y + m02 * in.z;
+ final double y = m10 * in.x + m11 * in.y + m12 * in.z;
+ final double z = m20 * in.x + m21 * in.y + m22 * in.z;
+ out.x = x;
+ out.y = y;
+ out.z = z;
+ }
+
+}
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.math;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+
+import static java.lang.Math.cos;
+import static java.lang.Math.sin;
+
+/**
+ * A unit quaternion representing a 3D rotation.
+ *
+ * <p>Quaternions provide a compact representation of rotations that avoids
+ * gimbal lock and enables smooth interpolation (slerp).</p>
+ *
+ * <p>Usage example:</p>
+ * <pre>{@code
+ * // Create a rotation from yaw and pitch angles
+ * Quaternion rotation = Quaternion.fromAngles(0.5, -0.3);
+ *
+ * // Apply rotation to a point
+ * Point3D point = new Point3D(1, 0, 0);
+ * rotation.rotate(point);
+ *
+ * // Combine rotations
+ * Quaternion combined = rotation.multiply(otherRotation);
+ * }</pre>
+ *
+ * @see Matrix3x3
+ * @see Transform
+ */
+public class Quaternion {
+
+ /**
+ * The scalar (real) component of the quaternion.
+ */
+ public double w;
+
+ /**
+ * The i component (x-axis rotation factor).
+ */
+ public double x;
+
+ /**
+ * The j component (y-axis rotation factor).
+ */
+ public double y;
+
+ /**
+ * The k component (z-axis rotation factor).
+ */
+ public double z;
+
+ /**
+ * Creates an identity quaternion representing no rotation.
+ * Equivalent to Quaternion(1, 0, 0, 0).
+ */
+ public Quaternion() {
+ this.w = 1;
+ this.x = 0;
+ this.y = 0;
+ this.z = 0;
+ }
+
+ /**
+ * Creates a quaternion with the specified components.
+ *
+ * @param w the scalar component
+ * @param x the i component
+ * @param y the j component
+ * @param z the k component
+ */
+ public Quaternion(final double w, final double x, final double y, final double z) {
+ this.w = w;
+ this.x = x;
+ this.y = y;
+ this.z = z;
+ }
+
+ /**
+ * Returns the identity quaternion representing no rotation.
+ *
+ * @return the identity quaternion (1, 0, 0, 0)
+ */
+ public static Quaternion identity() {
+ return new Quaternion(1, 0, 0, 0);
+ }
+
+ /**
+ * Creates a quaternion from an axis-angle representation.
+ *
+ * @param axis the rotation axis (must be normalized)
+ * @param angle the rotation angle in radians
+ * @return a quaternion representing the rotation
+ */
+ public static Quaternion fromAxisAngle(final Point3D axis, final double angle) {
+ final double halfAngle = angle / 2;
+ final double s = sin(halfAngle);
+ final double c = cos(halfAngle);
+ return new Quaternion(c, axis.x * s, axis.y * s, axis.z * s);
+ }
+
+ /**
+ * Creates a quaternion from XZ (yaw) and YZ (pitch) Euler angles.
+ *
+ * <p>The rotation is composed as yaw (around Y axis) followed by
+ * pitch (around X axis). No roll rotation is applied.</p>
+ *
+ * <p>For full 3-axis rotation, use {@link #fromAngles(double, double, double)}.</p>
+ *
+ * @param angleXZ the angle around the XZ axis (yaw) in radians
+ * @param angleYZ the angle around the YZ axis (pitch) in radians
+ * @return a quaternion representing the combined rotation
+ */
+ public static Quaternion fromAngles(final double angleXZ, final double angleYZ) {
+ return fromAngles(angleXZ, angleYZ, 0);
+ }
+
+ /**
+ * Creates a quaternion from full Euler angles (yaw, pitch, roll).
+ *
+ * <p>Rotation order: yaw (Y) → pitch (X) → roll (Z). This is the standard
+ * Y-X-Z Euler order commonly used for object placement in 3D scenes.</p>
+ *
+ * <p><b>Performance note:</b> This method uses a direct Euler-to-quaternion
+ * formula to avoid intermediate allocations.</p>
+ *
+ * @param yaw rotation around Y axis (horizontal heading) in radians
+ * @param pitch rotation around X axis (vertical tilt) in radians;
+ * positive values tilt upward
+ * @param roll rotation around Z axis (bank/tilt) in radians;
+ * positive values rotate clockwise when looking along +Z
+ * @return a quaternion representing the combined rotation
+ */
+ public static Quaternion fromAngles(final double yaw, final double pitch, final double roll) {
+ // Half angles for the Euler-to-quaternion conversion
+ final double cy = cos(yaw * 0.5);
+ final double sy = sin(yaw * 0.5);
+ final double cp = cos(pitch * 0.5);
+ final double sp = sin(pitch * 0.5);
+ final double cr = cos(roll * 0.5);
+ final double sr = sin(roll * 0.5);
+
+ // Direct formula for Y-X-Z Euler order with negated pitch
+ // Equivalent to: qRoll * qPitch(−pitch) * qYaw
+ return new Quaternion(
+ cr * cp * cy + sr * sp * sy, // w
+ -cr * sp * cy - sr * cp * sy, // x
+ cr * cp * sy - sr * sp * cy, // y
+ -cr * sp * sy + sr * cp * cy // z
+ );
+ }
+
+ /**
+ * Creates a copy of this quaternion.
+ *
+ * @return a new quaternion with the same component values
+ */
+ public Quaternion clone() {
+ return new Quaternion(w, x, y, z);
+ }
+
+ /**
+ * Copies the values from another quaternion into this one.
+ *
+ * @param other the quaternion to copy from
+ */
+ public void set(final Quaternion other) {
+ this.w = other.w;
+ this.x = other.x;
+ this.y = other.y;
+ this.z = other.z;
+ }
+
+ /**
+ * Multiplies this quaternion by another (Hamilton product).
+ *
+ * @param other the quaternion to multiply by
+ * @return a new quaternion representing the combined rotation
+ */
+ public Quaternion multiply(final Quaternion other) {
+ return new Quaternion(
+ w * other.w - x * other.x - y * other.y - z * other.z,
+ w * other.x + x * other.w + y * other.z - z * other.y,
+ w * other.y - x * other.z + y * other.w + z * other.x,
+ w * other.z + x * other.y - y * other.x + z * other.w
+ );
+ }
+
+ /**
+ * Normalizes this quaternion to unit length.
+ *
+ * @return this quaternion (for chaining)
+ */
+ public Quaternion normalize() {
+ final double len = Math.sqrt(w * w + x * x + y * y + z * z);
+ if (len > 0) {
+ w /= len;
+ x /= len;
+ y /= len;
+ z /= len;
+ }
+ return this;
+ }
+
+ /**
+ * Returns the inverse (conjugate) of this unit quaternion.
+ *
+ * <p>For a unit quaternion, the inverse equals the conjugate: (w, -x, -y, -z).
+ * This represents the opposite rotation.</p>
+ *
+ * @return a new quaternion representing the inverse rotation
+ */
+ public Quaternion invert() {
+ return new Quaternion(w, -x, -y, -z);
+ }
+
+ /**
+ * Converts this quaternion to a 3x3 rotation matrix.
+ *
+ * @return a new matrix representing this rotation
+ */
+ public Matrix3x3 toMatrix3x3() {
+ final Matrix3x3 m = new Matrix3x3();
+ copyToMatrix(m);
+ return m;
+ }
+
+ /**
+ * Copies this quaternion's rotation to an existing 3x3 matrix.
+ *
+ * <p>This method avoids allocation by reusing an existing Matrix3x3 instance.
+ * Used by Transform to avoid per-vertex allocation during rotation.</p>
+ *
+ * @param m the matrix to receive the rotation (modified in place)
+ */
+ public void copyToMatrix(final Matrix3x3 m) {
+ m.m00 = 1 - 2 * (y * y + z * z);
+ m.m01 = 2 * (x * y - w * z);
+ m.m02 = 2 * (x * z + w * y);
+
+ m.m10 = 2 * (x * y + w * z);
+ m.m11 = 1 - 2 * (x * x + z * z);
+ m.m12 = 2 * (y * z - w * x);
+
+ m.m20 = 2 * (x * z - w * y);
+ m.m21 = 2 * (y * z + w * x);
+ m.m22 = 1 - 2 * (x * x + y * y);
+ }
+
+ /**
+ * Converts this quaternion to a 3x3 rotation matrix.
+ * Alias for {@link #toMatrix3x3()} for API convenience.
+ *
+ * @return a new matrix representing this rotation
+ */
+ public Matrix3x3 toMatrix() {
+ return toMatrix3x3();
+ }
+
+ /**
+ * Extracts Euler angles (yaw, pitch, roll) from this quaternion.
+ *
+ * <p>This is the inverse of {@link #fromAngles(double, double, double)}.
+ * Returns angles in the Y-X-Z Euler order used by this engine.</p>
+ *
+ * @return array of {yaw, pitch, roll} in radians
+ */
+ public double[] toAngles() {
+ final Matrix3x3 m = toMatrix3x3();
+
+ final double pitch = -Math.asin(Math.max(-1, Math.min(1, m.m21)));
+ final double yaw = -Math.atan2(m.m20, m.m22);
+ final double roll = -Math.atan2(m.m01, m.m11);
+
+ return new double[]{yaw, pitch, roll};
+ }
+
+}
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.math;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+
+/**
+ * Represents a transformation in 3D space combining translation and rotation.
+ *
+ * <p>Transformations are applied in order: rotation first, then translation.</p>
+ *
+ * <p><b>Performance optimization:</b> The rotation matrix is cached and only
+ * recomputed when the rotation quaternion changes. This avoids allocating a
+ * new Matrix3x3 on every transform() call and avoids redundant quaternion-to-matrix
+ * conversions for vertices sharing the same transform.</p>
+ *
+ * <p><b>Mutability convention:</b></p>
+ * <ul>
+ * <li><b>Imperative verbs</b> ({@code set}, {@code setTranslation}, {@code transform})
+ * mutate this transform or the input point</li>
+ * <li><b>{@code with}-prefixed methods</b> ({@code withTransformed})
+ * return a new instance without modifying the original</li>
+ * </ul>
+ *
+ * <p><b>Thread safety:</b> The transform phase is single-threaded (synchronized in
+ * ShapeCollection.transformShapes()), so no synchronization is needed for the cached matrix.
+ * The matrix is computed once per Transform per frame and reused for all vertices.</p>
+ *
+ * @see Quaternion
+ * @see Point3D
+ */
+public class Transform implements Cloneable {
+
+ /**
+ * The translation applied after rotation.
+ */
+ private final Point3D translation;
+
+ /**
+ * The rotation applied before translation.
+ */
+ private final Quaternion rotation;
+
+ /**
+ * Cached rotation matrix for performance.
+ * Lazily computed when first needed and reused for subsequent transform() calls.
+ */
+ private Matrix3x3 cachedMatrix;
+
+ /**
+ * Flag indicating whether the cached matrix needs to be recomputed.
+ * Set to true when rotation is modified via set() or invalidateCache().
+ */
+ private boolean matrixDirty = true;
+
+ /**
+ * Creates a transform with no translation or rotation (identity transform).
+ */
+ public Transform() {
+ translation = new Point3D();
+ rotation = new Quaternion();
+ }
+
+ /**
+ * Creates a transform with the specified translation and no rotation.
+ *
+ * @param translation the translation
+ */
+ public Transform(final Point3D translation) {
+ this.translation = translation;
+ rotation = new Quaternion();
+ }
+
+ /**
+ * Creates a transform with the specified translation and rotation from Euler angles.
+ *
+ * @param translation the translation
+ * @param yaw the angle around the Y axis (horizontal heading) in radians
+ * @param pitch the angle around the X axis (vertical tilt) in radians
+ * @return a new transform with the specified translation and rotation
+ */
+ public static Transform fromAngles(final Point3D translation, final double yaw, final double pitch) {
+ return fromAngles(translation.x, translation.y, translation.z, yaw, pitch, 0);
+ }
+
+ /**
+ * Creates a transform with translation and full Euler rotation.
+ *
+ * <p>Rotation order: yaw (Y) → pitch (X) → roll (Z). This is the standard
+ * Y-X-Z Euler order commonly used for object placement in 3D scenes.</p>
+ *
+ * @param x translation X coordinate
+ * @param y translation Y coordinate
+ * @param z translation Z coordinate
+ * @param yaw rotation around Y axis (horizontal heading) in radians
+ * @param pitch rotation around X axis (vertical tilt) in radians
+ * @param roll rotation around Z axis (bank/tilt) in radians
+ * @return a new transform with the specified translation and rotation
+ */
+ public static Transform fromAngles(final double x, final double y, final double z,
+ final double yaw, final double pitch, final double roll) {
+ final Transform t = new Transform(new Point3D(x, y, z));
+ t.rotation.set(Quaternion.fromAngles(yaw, pitch, roll));
+ return t;
+ }
+
+ /**
+ * Creates a transform with the specified translation and rotation.
+ *
+ * @param translation the translation
+ * @param rotation the rotation (will be cloned)
+ */
+ public Transform(final Point3D translation, final Quaternion rotation) {
+ this.translation = translation;
+ this.rotation = rotation.clone();
+ }
+
+ /**
+ * Creates a copy of this transform with cloned translation and rotation.
+ *
+ * @return a new transform with the same translation and rotation values
+ */
+ @Override
+ public Transform clone() {
+ return new Transform(translation, rotation);
+ }
+
+ /**
+ * Returns the rotation component of this transform.
+ *
+ * <p><b>Warning:</b> If you modify the returned quaternion directly, you must
+ * call {@link #invalidateCache()} afterwards to ensure the cached rotation matrix
+ * is recomputed on the next call to {@link #transform(Point3D)}.</p>
+ *
+ * @return the rotation quaternion (mutable reference)
+ */
+ public Quaternion getRotation() {
+ return rotation;
+ }
+
+ /**
+ * Invalidates the cached rotation matrix.
+ *
+ * <p>Call this method after directly modifying the rotation quaternion
+ * (obtained via {@link #getRotation()}) to ensure the matrix is recomputed
+ * on the next call to {@link #transform(Point3D)}.</p>
+ *
+ * <p>This method is automatically called by {@link #set(double, double, double, double, double, double)}.</p>
+ *
+ * @return this transform (for chaining)
+ */
+ public Transform invalidateCache() {
+ matrixDirty = true;
+ return this;
+ }
+
+ /**
+ * Returns the translation component of this transform.
+ *
+ * @return the translation point (mutable reference)
+ */
+ public Point3D getTranslation() {
+ return translation;
+ }
+
+ /**
+ * Applies this transform to a point: rotation followed by translation.
+ *
+ * <p>Uses a cached rotation matrix to avoid allocation and redundant computation.
+ * The matrix is computed once (lazily) and reused for all subsequent calls
+ * until {@link #invalidateCache()} is called.</p>
+ *
+ * @param point the point to transform (modified in place)
+ * @see #withTransformed(Point3D) for the non-mutating version that returns a new point
+ */
+ public void transform(final Point3D point) {
+ getRotationMatrix().transform(point, point);
+ point.add(translation);
+ }
+
+ /**
+ * Returns the cached rotation matrix, computing it first if the cache
+ * is dirty or not yet initialized.
+ *
+ * <p>Package-private for internal use by {@link TransformStack}.
+ * Callers must not modify the returned matrix.</p>
+ *
+ * @return the cached rotation matrix
+ */
+ Matrix3x3 getRotationMatrix() {
+ // Lazily create and cache the rotation matrix
+ if (matrixDirty || cachedMatrix == null) {
+ if (cachedMatrix == null) {
+ cachedMatrix = new Matrix3x3();
+ }
+ rotation.copyToMatrix(cachedMatrix);
+ matrixDirty = false;
+ }
+ return cachedMatrix;
+ }
+
+ /**
+ * Returns a new point with this transform applied.
+ * The original point is not modified.
+ *
+ * @param point the point to transform
+ * @return a new Point3D with the transform applied
+ * @see #transform(Point3D) for the mutating version
+ */
+ public Point3D withTransformed(final Point3D point) {
+ final Point3D result = new Point3D(point);
+ transform(result);
+ return result;
+ }
+
+ /**
+ * Sets the translation for this transform by copying the values from the given point.
+ *
+ * @param translation the translation values to copy
+ * @return this transform (for chaining)
+ */
+ public Transform setTranslation(final Point3D translation) {
+ this.translation.x = translation.x;
+ this.translation.y = translation.y;
+ this.translation.z = translation.z;
+ return this;
+ }
+
+/**
+ * Sets both translation and rotation from Euler angles.
+ *
+ * <p>Rotation order: yaw (Y) → pitch (X) → roll (Z). This is the standard
+ * Y-X-Z Euler order commonly used for object placement in 3D scenes.</p>
+ *
+ * <p>This method invalidates the cached rotation matrix.</p>
+ *
+ * @param x translation X coordinate
+ * @param y translation Y coordinate
+ * @param z translation Z coordinate
+ * @param yaw rotation around Y axis (horizontal heading) in radians
+ * @param pitch rotation around X axis (vertical tilt) in radians
+ * @param roll rotation around Z axis (bank/tilt) in radians
+ * @return this transform for chaining
+ */
+ public Transform set(final double x, final double y, final double z,
+ final double yaw, final double pitch, final double roll) {
+ translation.x = x;
+ translation.y = y;
+ translation.z = z;
+ rotation.set(Quaternion.fromAngles(yaw, pitch, roll));
+ matrixDirty = true;
+ return this;
+ }
+
+}
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.math;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+
+/**
+ * Stack of transforms applied to points during rendering.
+ *
+ * <p>Transforms are applied in reverse order (last added is applied first).
+ * This supports hierarchical scene graphs where child objects are positioned
+ * relative to their parent objects.</p>
+ *
+ * <p><b>Example:</b></p>
+ * <pre>
+ * There is a ship in the sea. The ship moves along the sea, and every object
+ * on the ship moves with it. Inside the ship there is a car. The car moves
+ * along the ship, and every object on the car moves with it.
+ *
+ * To calculate the world position of an object inside the car:
+ * 1. Apply an object's position relative to the car
+ * 2. Apply the car's position relative to the ship
+ * 3. Apply ship's position relative to the world
+ * </pre>
+ *
+ * <p><b>Implementation: eager composition.</b> Every transform is a rigid
+ * motion (rotation then translation), and compositions of rigid motions are
+ * closed and associative, so the whole stack collapses into a single
+ * equivalent transform. The stack maintains the composed rotation matrix and
+ * translation for each level: {@link #addTransform} composes the pushed
+ * transform with the previous level's composite, and {@link #transform}
+ * applies only the top-level composite. Per-point cost is one 3x3
+ * matrix-vector multiply plus one addition, independent of stack depth.
+ * {@link #dropTransform} restores the parent composite for free.</p>
+ *
+ * <p><b>Contract:</b> composition is a snapshot taken at push time. Mutating
+ * a transform after pushing it has no effect on the stack until it is
+ * dropped and pushed again. The traversal rebuilds the stack every frame,
+ * so frame-to-frame changes are always picked up.</p>
+ *
+ * @see Transform
+ */
+public class TransformStack {
+
+ /**
+ * Maximum nesting depth of transforms.
+ * Fixed size for efficiency to avoid memory allocation during rendering.
+ */
+ private static final int MAX_DEPTH = 100;
+
+ /**
+ * Composed row-major 3x3 rotation matrices, 9 doubles per stack level.
+ * Level i holds the composition of all transforms pushed so far, in
+ * application order (level i's own transform applied first, level 0 last).
+ */
+ private final double[] rotations = new double[MAX_DEPTH * 9];
+
+ /**
+ * Composed translations, 3 doubles per stack level.
+ */
+ private final double[] translations = new double[MAX_DEPTH * 3];
+
+ /**
+ * The current number of transforms in the stack.
+ */
+ private int transformsCount = 0;
+
+ /**
+ * Creates a new empty transform stack.
+ */
+ public TransformStack() {
+ }
+
+ /**
+ * Creates a copy of another transform stack, duplicating its composed
+ * per-level transforms. Used to give each parallel transform worker its
+ * own stack preloaded with the same camera/parent state.
+ *
+ * @param source the stack to copy
+ */
+ public TransformStack(final TransformStack source) {
+ loadFrom(source);
+ }
+
+ /**
+ * Reinitializes this stack as a copy of {@code source} without
+ * allocating: the fixed-size arrays are reused. Used by the parallel
+ * transform coordinator to hand pooled stacks to chunk tasks.
+ *
+ * @param source the stack to copy
+ */
+ public void loadFrom(final TransformStack source) {
+ transformsCount = source.transformsCount;
+ System.arraycopy(source.rotations, 0, rotations, 0, transformsCount * 9);
+ System.arraycopy(source.translations, 0, translations, 0, transformsCount * 3);
+ }
+
+ /**
+ * Pushes a transform onto the stack, composing it with the current
+ * top-level composite.
+ *
+ * <p>If the previous composite is (Rp, tp) and the pushed transform is
+ * (Rn, tn), the new composite is R' = Rp * Rn, t' = Rp * tn + tp —
+ * the pushed transform applies first, then the previous composite.</p>
+ *
+ * @param transform the transform to push (snapshotted at push time)
+ */
+ public void addTransform(final Transform transform) {
+ final int i = transformsCount;
+ final int r = i * 9;
+ final int v = i * 3;
+
+ final Matrix3x3 rm = transform.getRotationMatrix();
+ final Point3D t = transform.getTranslation();
+
+ if (i == 0) {
+ rotations[r] = rm.m00;
+ rotations[r + 1] = rm.m01;
+ rotations[r + 2] = rm.m02;
+ rotations[r + 3] = rm.m10;
+ rotations[r + 4] = rm.m11;
+ rotations[r + 5] = rm.m12;
+ rotations[r + 6] = rm.m20;
+ rotations[r + 7] = rm.m21;
+ rotations[r + 8] = rm.m22;
+ translations[v] = t.x;
+ translations[v + 1] = t.y;
+ translations[v + 2] = t.z;
+ } else {
+ final int pr = r - 9;
+ final int pv = v - 3;
+
+ final double a00 = rotations[pr];
+ final double a01 = rotations[pr + 1];
+ final double a02 = rotations[pr + 2];
+ final double a10 = rotations[pr + 3];
+ final double a11 = rotations[pr + 4];
+ final double a12 = rotations[pr + 5];
+ final double a20 = rotations[pr + 6];
+ final double a21 = rotations[pr + 7];
+ final double a22 = rotations[pr + 8];
+
+ rotations[r] = a00 * rm.m00 + a01 * rm.m10 + a02 * rm.m20;
+ rotations[r + 1] = a00 * rm.m01 + a01 * rm.m11 + a02 * rm.m21;
+ rotations[r + 2] = a00 * rm.m02 + a01 * rm.m12 + a02 * rm.m22;
+ rotations[r + 3] = a10 * rm.m00 + a11 * rm.m10 + a12 * rm.m20;
+ rotations[r + 4] = a10 * rm.m01 + a11 * rm.m11 + a12 * rm.m21;
+ rotations[r + 5] = a10 * rm.m02 + a11 * rm.m12 + a12 * rm.m22;
+ rotations[r + 6] = a20 * rm.m00 + a21 * rm.m10 + a22 * rm.m20;
+ rotations[r + 7] = a20 * rm.m01 + a21 * rm.m11 + a22 * rm.m21;
+ rotations[r + 8] = a20 * rm.m02 + a21 * rm.m12 + a22 * rm.m22;
+
+ translations[v] = a00 * t.x + a01 * t.y + a02 * t.z + translations[pv];
+ translations[v + 1] = a10 * t.x + a11 * t.y + a12 * t.z + translations[pv + 1];
+ translations[v + 2] = a20 * t.x + a21 * t.y + a22 * t.z + translations[pv + 2];
+ }
+ transformsCount++;
+ }
+
+ /**
+ * Clears all transforms from the stack.
+ */
+ public void clear() {
+ transformsCount = 0;
+ }
+
+ /**
+ * Pops the most recently added transform from the stack. The parent
+ * level's composite is restored automatically.
+ */
+ public void dropTransform() {
+ transformsCount--;
+ }
+
+ /**
+ * Transforms a point through the whole stack by applying the top-level
+ * composed transform. Cost is independent of stack depth.
+ *
+ * @param coordinate the input coordinate (not modified)
+ * @param result the output coordinate (receives transformed result)
+ */
+ public void transform(final Point3D coordinate, final Point3D result) {
+ if (transformsCount == 0) {
+ result.clone(coordinate);
+ return;
+ }
+ final int r = (transformsCount - 1) * 9;
+ final int v = (transformsCount - 1) * 3;
+ final double x = coordinate.x;
+ final double y = coordinate.y;
+ final double z = coordinate.z;
+ result.x = rotations[r] * x + rotations[r + 1] * y + rotations[r + 2] * z + translations[v];
+ result.y = rotations[r + 3] * x + rotations[r + 4] * y + rotations[r + 5] * z + translations[v + 1];
+ result.z = rotations[r + 6] * x + rotations[r + 7] * y + rotations[r + 8] * z + translations[v + 2];
+ }
+
+ /**
+ * Copies the fully composed top-level transform (rotations 0..8, then
+ * translations 0..2) into {@code out} (length ≥ 12), for bulk
+ * loops that apply the same matrix to thousands of vertices
+ * ({@code TriangleMeshBlock}). Identity when the stack is empty.
+ * Applying it with the same expression order as
+ * {@link #transform(Point3D, Point3D)} yields bit-identical results.
+ *
+ * @param out destination array, length at least 12
+ */
+ public void getTopTransform(final double[] out) {
+ if (transformsCount == 0) {
+ out[0] = 1; out[1] = 0; out[2] = 0;
+ out[3] = 0; out[4] = 1; out[5] = 0;
+ out[6] = 0; out[7] = 0; out[8] = 1;
+ out[9] = 0; out[10] = 0; out[11] = 0;
+ return;
+ }
+ final int r = (transformsCount - 1) * 9;
+ final int v = (transformsCount - 1) * 3;
+ System.arraycopy(rotations, r, out, 0, 9);
+ System.arraycopy(translations, v, out, 9, 3);
+ }
+}
--- /dev/null
+/**
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ * <p>
+ * Math that is needed for the project.
+ */
+
+package eu.svjatoslav.aukio.e3d.math;
+
--- /dev/null
+/**
+ * This is root package for 3D engine. Since package name cannot start with a digit, it is named "e3d" instead,
+ * which stands for "Engine 3D".
+ */
+
+package eu.svjatoslav.aukio.e3d;
+
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.octree;
+import eu.svjatoslav.aukio.e3d.geometry.IntegerPoint;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.octree.raytracer.Ray;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+
+import static java.lang.Integer.max;
+import static java.lang.Integer.min;
+
+/**
+ * Sparse voxel octree for 3D volume storage and ray tracing.
+ *
+ * <p>The octree represents a 3D volume with three cell types:</p>
+ * <ul>
+ * <li><b>UNUSED</b> - Empty cell, not yet allocated</li>
+ * <li><b>SOLID</b> - Contains color and illumination data</li>
+ * <li><b>CLUSTER</b> - Contains pointers to 8 child cells (for subdivision)</li>
+ * </ul>
+ *
+ * <p>Cell data is stored in parallel arrays ({@code cell1} through {@code cell8})
+ * for memory efficiency. Each array stores different aspects of cell data.</p>
+ *
+ * <p><b>Status:</b> demo-only subsystem (used by {@code OctreeDemo}).
+ * The ray-traversal core ({@code traceCell}, ~590 lines of per-octant
+ * code) has no unit coverage and is exercised only through the demo's
+ * golden image; treat changes there as unverified by anything except the
+ * golden. The cell-pool capacity is fixed at construction —
+ * {@link #getNewCellPointer()} throws {@link IllegalStateException} when
+ * the pool is exhausted (it used to hang in an infinite rescan loop).</p>
+ *
+ * @see eu.svjatoslav.aukio.e3d.renderer.octree.raytracer.RayTracer
+ * @see eu.svjatoslav.aukio.e3d.renderer.octree.raytracer.Ray
+ */
+public class OctreeVolume {
+
+ /** Return value indicating no intersection during ray tracing. */
+ public static final int TRACE_NO_HIT = -1;
+
+ /** Cell state marker for solid cells. */
+ private static final int CELL_STATE_SOLID = -2;
+
+ /** Cell state marker for unused/empty cells. */
+ private static final int CELL_STATE_UNUSED = -1;
+
+ /** Cell data array 1: stores cell state and first child pointer. */
+ public int[] cell1;
+ /** Cell data array 2: stores color values. */
+ public int[] cell2;
+ /** Cell data array 3: stores illumination values. */
+ public int[] cell3;
+ /** Cell data array 4: stores child pointer 4. */
+ public int[] cell4;
+ /** Cell data array 5: stores child pointer 5. */
+ public int[] cell5;
+ /** Cell data array 6: stores child pointer 6. */
+ public int[] cell6;
+ /** Cell data array 7: stores child pointer 7. */
+ public int[] cell7;
+ /** Cell data array 8: stores child pointer 8. */
+ public int[] cell8;
+
+ /**
+ * Pointer to the next unused cell in the allocation buffer.
+ */
+ public int cellAllocationPointer = 0;
+
+ /** Number of currently allocated cells. */
+ public int usedCellsCount = 0;
+
+ /** Size of the root (master) cell in world units. */
+ public int masterCellSize;
+
+ /**
+ * Creates a new octree volume with default buffer size (1.5M cells)
+ * and master cell size of 256*64 units.
+ */
+ public OctreeVolume() {
+ initWorld(1500000, 256 * 64);
+ }
+
+ /**
+ * Subdivides a solid cell into 8 child cells, each with the same color and illumination.
+ *
+ * @param pointer the cell to break up
+ */
+ public void breakSolidCell(final int pointer) {
+ final int color = getCellColor(pointer);
+ final int illumination = getCellIllumination(pointer);
+
+ cell1[pointer] = makeNewCell(color, illumination);
+ cell2[pointer] = makeNewCell(color, illumination);
+ cell3[pointer] = makeNewCell(color, illumination);
+ cell4[pointer] = makeNewCell(color, illumination);
+ cell5[pointer] = makeNewCell(color, illumination);
+ cell6[pointer] = makeNewCell(color, illumination);
+ cell7[pointer] = makeNewCell(color, illumination);
+ cell8[pointer] = makeNewCell(color, illumination);
+ }
+
+ /**
+ * Clears the cell.
+ * @param pointer Pointer to the cell.
+ */
+ public void clearCell(final int pointer) {
+ cell1[pointer] = 0;
+ cell2[pointer] = 0;
+ cell3[pointer] = 0;
+ cell4[pointer] = 0;
+
+ cell5[pointer] = 0;
+ cell6[pointer] = 0;
+ cell7[pointer] = 0;
+ cell8[pointer] = 0;
+ }
+
+ /**
+ * Marks a cell as deleted and returns it to the unused pool.
+ *
+ * @param cellPointer the cell to delete
+ */
+ public void deleteCell(final int cellPointer) {
+ clearCell(cellPointer);
+ cell1[cellPointer] = CELL_STATE_UNUSED;
+ usedCellsCount--;
+ }
+
+ /**
+ * Tests whether a ray intersects with a cubic region.
+ *
+ * @param cubeX the X center of the cube
+ * @param cubeY the Y center of the cube
+ * @param cubeZ the Z center of the cube
+ * @param cubeSize the half-size of the cube
+ * @param r the ray to test
+ * @return intersection type code, or 0 if no intersection
+ */
+ public int doesIntersect(final int cubeX, final int cubeY, final int cubeZ,
+ final int cubeSize, final Ray r) {
+
+ // ray starts inside the cube
+ if ((cubeX - cubeSize) < r.origin.x)
+ if ((cubeX + cubeSize) > r.origin.x)
+ if ((cubeY - cubeSize) < r.origin.y)
+ if ((cubeY + cubeSize) > r.origin.y)
+ if ((cubeZ - cubeSize) < r.origin.z)
+ if ((cubeZ + cubeSize) > r.origin.z) {
+ r.hitPoint = r.origin.clone();
+ return 1;
+ }
+ // back face
+ if (r.direction.z > 0)
+ if ((cubeZ - cubeSize) > r.origin.z) {
+ final double mult = ((cubeZ - cubeSize) - r.origin.z) / r.direction.z;
+ final double hitX = (r.direction.x * mult) + r.origin.x;
+ if ((cubeX - cubeSize) < hitX)
+ if ((cubeX + cubeSize) > hitX) {
+ final double hitY = (r.direction.y * mult) + r.origin.y;
+ if ((cubeY - cubeSize) < hitY)
+ if ((cubeY + cubeSize) > hitY) {
+ r.hitPoint = new Point3D(hitX, hitY, cubeZ
+ - cubeSize);
+ return 2;
+ }
+ }
+ }
+
+ // up face
+ if (r.direction.y > 0)
+ if ((cubeY - cubeSize) > r.origin.y) {
+ final double mult = ((cubeY - cubeSize) - r.origin.y) / r.direction.y;
+ final double hitX = (r.direction.x * mult) + r.origin.x;
+ if ((cubeX - cubeSize) < hitX)
+ if ((cubeX + cubeSize) > hitX) {
+ final double hitZ = (r.direction.z * mult) + r.origin.z;
+ if ((cubeZ - cubeSize) < hitZ)
+ if ((cubeZ + cubeSize) > hitZ) {
+ r.hitPoint = new Point3D(hitX, cubeY - cubeSize,
+ hitZ);
+ return 3;
+ }
+ }
+ }
+
+ // left face
+ if (r.direction.x > 0)
+ if ((cubeX - cubeSize) > r.origin.x) {
+ final double mult = ((cubeX - cubeSize) - r.origin.x) / r.direction.x;
+ final double hitY = (r.direction.y * mult) + r.origin.y;
+ if ((cubeY - cubeSize) < hitY)
+ if ((cubeY + cubeSize) > hitY) {
+ final double hitZ = (r.direction.z * mult) + r.origin.z;
+ if ((cubeZ - cubeSize) < hitZ)
+ if ((cubeZ + cubeSize) > hitZ) {
+ r.hitPoint = new Point3D(cubeX - cubeSize, hitY,
+ hitZ);
+ return 4;
+ }
+ }
+ }
+
+ // front face
+ if (r.direction.z < 0)
+ if ((cubeZ + cubeSize) < r.origin.z) {
+ final double mult = ((cubeZ + cubeSize) - r.origin.z) / r.direction.z;
+ final double hitX = (r.direction.x * mult) + r.origin.x;
+ if ((cubeX - cubeSize) < hitX)
+ if ((cubeX + cubeSize) > hitX) {
+ final double hitY = (r.direction.y * mult) + r.origin.y;
+ if ((cubeY - cubeSize) < hitY)
+ if ((cubeY + cubeSize) > hitY) {
+ r.hitPoint = new Point3D(hitX, hitY, cubeZ
+ + cubeSize);
+ return 5;
+ }
+ }
+ }
+
+ // down face
+ if (r.direction.y < 0)
+ if ((cubeY + cubeSize) < r.origin.y) {
+ final double mult = ((cubeY + cubeSize) - r.origin.y) / r.direction.y;
+ final double hitX = (r.direction.x * mult) + r.origin.x;
+ if ((cubeX - cubeSize) < hitX)
+ if ((cubeX + cubeSize) > hitX) {
+ final double hitZ = (r.direction.z * mult) + r.origin.z;
+ if ((cubeZ - cubeSize) < hitZ)
+ if ((cubeZ + cubeSize) > hitZ) {
+ r.hitPoint = new Point3D(hitX, cubeY + cubeSize,
+ hitZ);
+ return 6;
+ }
+ }
+ }
+
+ // right face
+ if (r.direction.x < 0)
+ if ((cubeX + cubeSize) < r.origin.x) {
+ final double mult = ((cubeX + cubeSize) - r.origin.x) / r.direction.x;
+ final double hitY = (r.direction.y * mult) + r.origin.y;
+ if ((cubeY - cubeSize) < hitY)
+ if ((cubeY + cubeSize) > hitY) {
+ final double hitZ = (r.direction.z * mult) + r.origin.z;
+ if ((cubeZ - cubeSize) < hitZ)
+ if ((cubeZ + cubeSize) > hitZ) {
+ r.hitPoint = new Point3D(cubeX + cubeSize, hitY,
+ hitZ);
+ return 7;
+ }
+ }
+ }
+ return 0;
+ }
+
+ /**
+ * Fills a 3D rectangular region with solid cells of the given color.
+ *
+ * @param p1 one corner of the rectangle
+ * @param p2 the opposite corner of the rectangle
+ * @param color the color to fill with
+ */
+ public void fillRectangle(IntegerPoint p1, IntegerPoint p2, Color color) {
+
+ int x1 = min(p1.x, p2.x);
+ int x2 = max(p1.x, p2.x);
+ int y1 = min(p1.y, p2.y);
+ int y2 = max(p1.y, p2.y);
+ int z1 = min(p1.z, p2.z);
+ int z2 = max(p1.z, p2.z);
+
+ for (int x = x1; x <= x2; x++)
+ for (int y = y1; y <= y2; y++)
+ for (int z = z1; z <= z2; z++)
+ putCell(x, y, z, 0, 0, 0, masterCellSize, 0, color);
+ }
+
+ /**
+ * Returns the color value stored in a solid cell.
+ *
+ * @param pointer the cell pointer
+ * @return the packed RGB color value
+ */
+ public int getCellColor(final int pointer) {
+ return cell2[pointer];
+ }
+
+ /**
+ * Returns the illumination value stored in a solid cell.
+ *
+ * @param pointer the cell pointer
+ * @return the packed RGB illumination value
+ */
+ public int getCellIllumination(final int pointer) {
+ return cell3[pointer];
+ }
+
+ /**
+ * Initializes the octree storage arrays with the specified buffer size and root cell size.
+ *
+ * @param bufferLength the number of cells to allocate space for
+ * @param masterCellSize the size of the root cell in world units
+ */
+ public void initWorld(final int bufferLength, final int masterCellSize) {
+ // System.out.println("Initializing new world");
+
+ // initialize world storage buffer
+ this.masterCellSize = masterCellSize;
+
+ cell1 = new int[bufferLength];
+ cell2 = new int[bufferLength];
+ cell3 = new int[bufferLength];
+ cell4 = new int[bufferLength];
+
+ cell5 = new int[bufferLength];
+ cell6 = new int[bufferLength];
+ cell7 = new int[bufferLength];
+ cell8 = new int[bufferLength];
+
+ for (int i = 0; i < bufferLength; i++)
+ cell1[i] = CELL_STATE_UNUSED;
+
+ // initialize master cell (occupies index 0 without being
+ // CELL_STATE_UNUSED — count it so usedCellsCount stays honest)
+ clearCell(0);
+ usedCellsCount = 1;
+ }
+
+ /**
+ * Checks if the cell at the given pointer is a solid (leaf) cell.
+ *
+ * @param pointer the cell pointer to check
+ * @return {@code true} if the cell is solid
+ */
+ public boolean isCellSolid(final int pointer) {
+ return cell1[pointer] == CELL_STATE_SOLID;
+ }
+
+ /**
+ * Scans cells arrays and returns pointer to found unused cell.
+ *
+ * <p>Fails loudly on pool exhaustion — the previous version looped
+ * forever, rescanning the full pool on every wrap. The authoritative
+ * check is a full scan cycle back to the start position (the
+ * {@code usedCellsCount} fast path alone is insufficient: the master
+ * cell at index 0 occupies a slot without being counted).</p>
+ *
+ * @return pointer to found unused cell
+ * @throws IllegalStateException when the cell pool is full
+ */
+ public int getNewCellPointer() {
+ if (usedCellsCount >= cell1.length)
+ throw poolExhausted();
+
+ final int start = cellAllocationPointer;
+ while (true) {
+ // ensure that cell allocation pointer is in bounds
+ if (cellAllocationPointer >= cell1.length)
+ cellAllocationPointer = 0;
+
+ if (cell1[cellAllocationPointer] == CELL_STATE_UNUSED) {
+ // unused cell found
+ clearCell(cellAllocationPointer);
+
+ usedCellsCount++;
+ return cellAllocationPointer;
+ }
+
+ cellAllocationPointer++;
+ if (cellAllocationPointer == start)
+ throw poolExhausted();
+ }
+ }
+
+ /** Builds the pool-exhaustion exception (shared by both guards). */
+ private IllegalStateException poolExhausted() {
+ return new IllegalStateException(
+ "Octree cell pool exhausted: all " + cell1.length
+ + " cells are in use. Increase the pool size"
+ + " at OctreeVolume construction or reduce"
+ + " scene voxel density.");
+ }
+
+ /**
+ * Allocates a new solid cell with the given color and illumination.
+ *
+ * @param color the color value for the new cell
+ * @param illumination the illumination value for the new cell
+ * @return the pointer to the newly allocated cell
+ */
+ public int makeNewCell(final int color, final int illumination) {
+ final int pointer = getNewCellPointer();
+ markCellAsSolid(pointer);
+ setCellColor(pointer, color);
+ setCellIllumination(pointer, illumination);
+ return pointer;
+ }
+
+ /**
+ * Mark cell as solid.
+ *
+ * @param pointer pointer to cell
+ */
+ public void markCellAsSolid(final int pointer) {
+ cell1[pointer] = CELL_STATE_SOLID;
+ }
+
+ /**
+ * Stores a voxel at the given world coordinates with the specified color.
+ *
+ * @param x the X coordinate
+ * @param y the Y coordinate
+ * @param z the Z coordinate
+ * @param color the color of the voxel
+ */
+ public void putCell(final int x, final int y, final int z, final Color color) {
+ putCell(x, y, z, 0, 0, 0, masterCellSize, 0, color);
+ }
+
+ private void putCell(final int x, final int y, final int z,
+ final int cellX, final int cellY, final int cellZ,
+ final int cellSize, final int cellPointer, final Color color) {
+
+ if (cellSize > 1) {
+
+ // if case of big cell
+ if (isCellSolid(cellPointer)) {
+
+ // if cell is already a needed color, do nothing
+ if (getCellColor(cellPointer) == color.toInt())
+ return;
+
+ // otherwise break cell up
+ breakSolidCell(cellPointer);
+
+ // continue, as if it is cluster now
+ }
+
+ // decide which subcube to use
+ int[] subCubeArray;
+ int subX, subY, subZ;
+
+ if (x > cellX) {
+ subX = (cellSize / 2) + cellX;
+ if (y > cellY) {
+ subY = (cellSize / 2) + cellY;
+ if (z > cellZ) {
+ subZ = (cellSize / 2) + cellZ;
+ // 7
+ subCubeArray = cell7;
+ } else {
+ subZ = (-cellSize / 2) + cellZ;
+ // 3
+ subCubeArray = cell3;
+ }
+ } else {
+ subY = (-cellSize / 2) + cellY;
+ if (z > cellZ) {
+ subZ = (cellSize / 2) + cellZ;
+ // 6
+ subCubeArray = cell6;
+ } else {
+ subZ = (-cellSize / 2) + cellZ;
+ // 2
+ subCubeArray = cell2;
+ }
+ }
+ } else {
+ subX = (-cellSize / 2) + cellX;
+ if (y > cellY) {
+ subY = (cellSize / 2) + cellY;
+ if (z > cellZ) {
+ subZ = (cellSize / 2) + cellZ;
+ // 8
+ subCubeArray = cell8;
+ } else {
+ subZ = (-cellSize / 2) + cellZ;
+ // 4
+ subCubeArray = cell4;
+ }
+ } else {
+ subY = (-cellSize / 2) + cellY;
+ if (z > cellZ) {
+ subZ = (cellSize / 2) + cellZ;
+ // 5
+ subCubeArray = cell5;
+ } else {
+ subZ = (-cellSize / 2) + cellZ;
+ // 1
+ subCubeArray = cell1;
+ }
+ }
+ }
+
+ int subCubePointer;
+ if (subCubeArray[cellPointer] == 0) {
+ // create empty cluster
+ subCubePointer = getNewCellPointer();
+ subCubeArray[cellPointer] = subCubePointer;
+ } else
+ subCubePointer = subCubeArray[cellPointer];
+
+ putCell(x, y, z, subX, subY, subZ, cellSize / 2, subCubePointer,
+ color);
+ } else {
+ cell1[cellPointer] = CELL_STATE_SOLID;
+ cell2[cellPointer] = color.toInt();
+ cell3[cellPointer] = CELL_STATE_UNUSED;
+ // System.out.println("Cell written!");
+ }
+ }
+
+ /**
+ * Sets the color value for the cell at the given pointer.
+ *
+ * @param pointer the cell pointer
+ * @param color the color value to set
+ */
+ public void setCellColor(final int pointer, final int color) {
+ cell2[pointer] = color;
+ }
+
+ /**
+ * Sets the illumination value for the cell at the given pointer.
+ *
+ * @param pointer the cell pointer
+ * @param illumination the illumination value to set
+ */
+ public void setCellIllumination(final int pointer, final int illumination) {
+ cell3[pointer] = illumination;
+ }
+
+ /**
+ * Traces a ray through the octree to find an intersecting solid cell.
+ *
+ * @param cellX the X coordinate of the current cell center
+ * @param cellY the Y coordinate of the current cell center
+ * @param cellZ the Z coordinate of the current cell center
+ * @param cellSize the size of the current cell
+ * @param pointer the pointer to the current cell
+ * @param ray the ray to trace
+ * @return pointer to intersecting cell or TRACE_NO_HIT if no intersection
+ */
+ public int traceCell(final int cellX, final int cellY, final int cellZ,
+ final int cellSize, final int pointer, final Ray ray) {
+ if (isCellSolid(pointer)) {
+ // solid cell
+ if (doesIntersect(cellX, cellY, cellZ, cellSize, ray) != 0) {
+ ray.hitCellSize = cellSize;
+ ray.hitCellX = cellX;
+ ray.hitCellY = cellY;
+ ray.hitCellZ = cellZ;
+ return pointer;
+ }
+ return TRACE_NO_HIT;
+ } else // cluster
+ if (doesIntersect(cellX, cellY, cellZ, cellSize, ray) != 0) {
+ final int halfOfCellSize = cellSize / 2;
+ int rayIntersectionResult;
+
+ if (ray.origin.x > cellX) {
+ if (ray.origin.y > cellY) {
+ if (ray.origin.z > cellZ) {
+ // 7
+ // 6 8 3 5 2 4 1
+
+ if (cell7[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ + halfOfCellSize, cellY + halfOfCellSize,
+ cellZ + halfOfCellSize, halfOfCellSize,
+ cell7[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+ if (cell6[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ + halfOfCellSize, cellY - halfOfCellSize,
+ cellZ + halfOfCellSize, halfOfCellSize,
+ cell6[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+ if (cell8[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ - halfOfCellSize, cellY + halfOfCellSize,
+ cellZ + halfOfCellSize, halfOfCellSize,
+ cell8[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+ if (cell3[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ + halfOfCellSize, cellY + halfOfCellSize,
+ cellZ - halfOfCellSize, halfOfCellSize,
+ cell3[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell2[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ + halfOfCellSize, cellY - halfOfCellSize,
+ cellZ - halfOfCellSize, halfOfCellSize,
+ cell2[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+ if (cell4[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ - halfOfCellSize, cellY + halfOfCellSize,
+ cellZ - halfOfCellSize, halfOfCellSize,
+ cell4[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell5[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ - halfOfCellSize, cellY - halfOfCellSize,
+ cellZ + halfOfCellSize, halfOfCellSize,
+ cell5[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell1[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ - halfOfCellSize, cellY - halfOfCellSize,
+ cellZ - halfOfCellSize, halfOfCellSize,
+ cell1[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ } else {
+ // 3
+ // 2 4 7 1 6 8 5
+ if (cell3[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ + halfOfCellSize, cellY + halfOfCellSize,
+ cellZ - halfOfCellSize, halfOfCellSize,
+ cell3[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell2[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ + halfOfCellSize, cellY - halfOfCellSize,
+ cellZ - halfOfCellSize, halfOfCellSize,
+ cell2[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+ if (cell4[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ - halfOfCellSize, cellY + halfOfCellSize,
+ cellZ - halfOfCellSize, halfOfCellSize,
+ cell4[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell7[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ + halfOfCellSize, cellY + halfOfCellSize,
+ cellZ + halfOfCellSize, halfOfCellSize,
+ cell7[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+ if (cell6[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ + halfOfCellSize, cellY - halfOfCellSize,
+ cellZ + halfOfCellSize, halfOfCellSize,
+ cell6[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+ if (cell8[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ - halfOfCellSize, cellY + halfOfCellSize,
+ cellZ + halfOfCellSize, halfOfCellSize,
+ cell8[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell1[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ - halfOfCellSize, cellY - halfOfCellSize,
+ cellZ - halfOfCellSize, halfOfCellSize,
+ cell1[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell5[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ - halfOfCellSize, cellY - halfOfCellSize,
+ cellZ + halfOfCellSize, halfOfCellSize,
+ cell5[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ }
+ } else if (ray.origin.z > cellZ) {
+ // 6
+ // 5 2 7 8 1 3 4
+ if (cell6[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ + halfOfCellSize, cellY - halfOfCellSize, cellZ
+ + halfOfCellSize, halfOfCellSize, cell6[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell7[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ + halfOfCellSize, cellY + halfOfCellSize, cellZ
+ + halfOfCellSize, halfOfCellSize, cell7[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+ if (cell2[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ + halfOfCellSize, cellY - halfOfCellSize, cellZ
+ - halfOfCellSize, halfOfCellSize, cell2[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+ if (cell5[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ - halfOfCellSize, cellY - halfOfCellSize, cellZ
+ + halfOfCellSize, halfOfCellSize, cell5[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+ if (cell8[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ - halfOfCellSize, cellY + halfOfCellSize, cellZ
+ + halfOfCellSize, halfOfCellSize, cell8[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+ if (cell3[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ + halfOfCellSize, cellY + halfOfCellSize, cellZ
+ - halfOfCellSize, halfOfCellSize, cell3[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell1[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ - halfOfCellSize, cellY - halfOfCellSize, cellZ
+ - halfOfCellSize, halfOfCellSize, cell1[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+ if (cell4[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ - halfOfCellSize, cellY + halfOfCellSize, cellZ
+ - halfOfCellSize, halfOfCellSize, cell4[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ } else {
+ // 2
+ // 1 3 6 5 4 7 8
+ if (cell2[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ + halfOfCellSize, cellY - halfOfCellSize, cellZ
+ - halfOfCellSize, halfOfCellSize, cell2[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell3[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ + halfOfCellSize, cellY + halfOfCellSize, cellZ
+ - halfOfCellSize, halfOfCellSize, cell3[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell1[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ - halfOfCellSize, cellY - halfOfCellSize, cellZ
+ - halfOfCellSize, halfOfCellSize, cell1[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+ if (cell6[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ + halfOfCellSize, cellY - halfOfCellSize, cellZ
+ + halfOfCellSize, halfOfCellSize, cell6[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell7[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ + halfOfCellSize, cellY + halfOfCellSize, cellZ
+ + halfOfCellSize, halfOfCellSize, cell7[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+ if (cell5[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ - halfOfCellSize, cellY - halfOfCellSize, cellZ
+ + halfOfCellSize, halfOfCellSize, cell5[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+ if (cell4[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ - halfOfCellSize, cellY + halfOfCellSize, cellZ
+ - halfOfCellSize, halfOfCellSize, cell4[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+ if (cell8[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ - halfOfCellSize, cellY + halfOfCellSize, cellZ
+ + halfOfCellSize, halfOfCellSize, cell8[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ }
+ } else if (ray.origin.y > cellY) {
+ if (ray.origin.z > cellZ) {
+ // 8
+ // 5 7 4 1 6 3 2
+
+ if (cell8[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ - halfOfCellSize, cellY + halfOfCellSize, cellZ
+ + halfOfCellSize, halfOfCellSize, cell8[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+ if (cell7[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ + halfOfCellSize, cellY + halfOfCellSize, cellZ
+ + halfOfCellSize, halfOfCellSize, cell7[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+ if (cell5[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ - halfOfCellSize, cellY - halfOfCellSize, cellZ
+ + halfOfCellSize, halfOfCellSize, cell5[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+ if (cell4[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ - halfOfCellSize, cellY + halfOfCellSize, cellZ
+ - halfOfCellSize, halfOfCellSize, cell4[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell3[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ + halfOfCellSize, cellY + halfOfCellSize, cellZ
+ - halfOfCellSize, halfOfCellSize, cell3[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell1[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ - halfOfCellSize, cellY - halfOfCellSize, cellZ
+ - halfOfCellSize, halfOfCellSize, cell1[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+ if (cell6[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ + halfOfCellSize, cellY - halfOfCellSize, cellZ
+ + halfOfCellSize, halfOfCellSize, cell6[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell2[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ + halfOfCellSize, cellY - halfOfCellSize, cellZ
+ - halfOfCellSize, halfOfCellSize, cell2[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ } else {
+ // 4
+ // 1 3 8 5 7 2 6
+
+ if (cell4[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ - halfOfCellSize, cellY + halfOfCellSize, cellZ
+ - halfOfCellSize, halfOfCellSize, cell4[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell8[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ - halfOfCellSize, cellY + halfOfCellSize, cellZ
+ + halfOfCellSize, halfOfCellSize, cell8[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+ if (cell3[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ + halfOfCellSize, cellY + halfOfCellSize, cellZ
+ - halfOfCellSize, halfOfCellSize, cell3[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell1[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ - halfOfCellSize, cellY - halfOfCellSize, cellZ
+ - halfOfCellSize, halfOfCellSize, cell1[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+ if (cell7[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ + halfOfCellSize, cellY + halfOfCellSize, cellZ
+ + halfOfCellSize, halfOfCellSize, cell7[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+ if (cell5[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ - halfOfCellSize, cellY - halfOfCellSize, cellZ
+ + halfOfCellSize, halfOfCellSize, cell5[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell2[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ + halfOfCellSize, cellY - halfOfCellSize, cellZ
+ - halfOfCellSize, halfOfCellSize, cell2[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+ if (cell6[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX
+ + halfOfCellSize, cellY - halfOfCellSize, cellZ
+ + halfOfCellSize, halfOfCellSize, cell6[pointer],
+ ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ }
+ } else if (ray.origin.z > cellZ) {
+ // 5
+ // 1 6 8 4 2 7 3
+
+ if (cell5[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX - halfOfCellSize,
+ cellY - halfOfCellSize, cellZ + halfOfCellSize,
+ halfOfCellSize, cell5[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell1[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX - halfOfCellSize,
+ cellY - halfOfCellSize, cellZ - halfOfCellSize,
+ halfOfCellSize, cell1[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell6[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX + halfOfCellSize,
+ cellY - halfOfCellSize, cellZ + halfOfCellSize,
+ halfOfCellSize, cell6[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell8[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX - halfOfCellSize,
+ cellY + halfOfCellSize, cellZ + halfOfCellSize,
+ halfOfCellSize, cell8[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell4[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX - halfOfCellSize,
+ cellY + halfOfCellSize, cellZ - halfOfCellSize,
+ halfOfCellSize, cell4[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell7[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX + halfOfCellSize,
+ cellY + halfOfCellSize, cellZ + halfOfCellSize,
+ halfOfCellSize, cell7[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell2[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX + halfOfCellSize,
+ cellY - halfOfCellSize, cellZ - halfOfCellSize,
+ halfOfCellSize, cell2[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell3[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX + halfOfCellSize,
+ cellY + halfOfCellSize, cellZ - halfOfCellSize,
+ halfOfCellSize, cell3[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ } else {
+ // 1
+ // 5 2 4 8 6 3 7
+
+ if (cell1[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX - halfOfCellSize,
+ cellY - halfOfCellSize, cellZ - halfOfCellSize,
+ halfOfCellSize, cell1[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell5[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX - halfOfCellSize,
+ cellY - halfOfCellSize, cellZ + halfOfCellSize,
+ halfOfCellSize, cell5[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+ if (cell2[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX + halfOfCellSize,
+ cellY - halfOfCellSize, cellZ - halfOfCellSize,
+ halfOfCellSize, cell2[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell4[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX - halfOfCellSize,
+ cellY + halfOfCellSize, cellZ - halfOfCellSize,
+ halfOfCellSize, cell4[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell6[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX + halfOfCellSize,
+ cellY - halfOfCellSize, cellZ + halfOfCellSize,
+ halfOfCellSize, cell6[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell8[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX - halfOfCellSize,
+ cellY + halfOfCellSize, cellZ + halfOfCellSize,
+ halfOfCellSize, cell8[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+
+ if (cell3[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX + halfOfCellSize,
+ cellY + halfOfCellSize, cellZ - halfOfCellSize,
+ halfOfCellSize, cell3[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+ if (cell7[pointer] != 0) {
+ rayIntersectionResult = traceCell(cellX + halfOfCellSize,
+ cellY + halfOfCellSize, cellZ + halfOfCellSize,
+ halfOfCellSize, cell7[pointer], ray);
+ if (rayIntersectionResult >= 0)
+ return rayIntersectionResult;
+ }
+ }
+ }
+ return TRACE_NO_HIT;
+ }
+
+}
--- /dev/null
+/**
+ * Octree-based voxel volume representation and rendering for the Aukio 3D engine.
+ *
+ * <p>This package provides a volumetric data structure based on an octree, which enables
+ * efficient storage and rendering of voxel data. The octree recursively subdivides 3D space
+ * into eight octants, achieving significant data compression for sparse or repetitive volumes.</p>
+ *
+ * <p>Key classes:</p>
+ * <ul>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.octree.OctreeVolume} - the main octree data structure
+ * for storing and querying voxel cells</li>
+ * <li>{@link eu.svjatoslav.aukio.e3d.geometry.IntegerPoint} - integer 3D coordinate used
+ * for voxel addressing</li>
+ * </ul>
+ *
+ * @see eu.svjatoslav.aukio.e3d.renderer.octree.raytracer ray tracing through octree volumes
+ */
+
+package eu.svjatoslav.aukio.e3d.renderer.octree;
+import eu.svjatoslav.aukio.e3d.geometry.IntegerPoint;
+
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.octree.raytracer;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.geometry.Camera;
+import eu.svjatoslav.aukio.e3d.math.Matrix3x3;
+
+import static eu.svjatoslav.aukio.e3d.renderer.octree.raytracer.RaytracingCamera.SIZE;
+
+/**
+ * Represents camera view. Used to compute direction of rays during ray tracing.
+ */
+public class CameraView {
+
+ /**
+ * Camera view coordinates.
+ */
+ Point3D cameraCenter, topLeft, topRight, bottomLeft, bottomRight;
+
+ /**
+ * Creates a camera view for ray tracing from the given camera and zoom level.
+ *
+ * @param camera the camera to create a view for
+ * @param zoom the zoom level (scales the view frustum)
+ */
+ public CameraView(final Camera camera, final double zoom) {
+ final float viewAngle = (float) .6;
+ cameraCenter = new Point3D();
+ topLeft = new Point3D(0, 0, SIZE).rotate(-viewAngle, -viewAngle);
+ topRight = new Point3D(0, 0, SIZE).rotate(viewAngle, -viewAngle);
+ bottomLeft = new Point3D(0, 0, SIZE).rotate(-viewAngle, viewAngle);
+ bottomRight = new Point3D(0, 0, SIZE).rotate(viewAngle, viewAngle);
+
+ final Matrix3x3 m = camera.getTransform().getRotation().invert().toMatrix3x3();
+ final Point3D temp = new Point3D();
+
+ temp.clone(topLeft);
+ m.transform(temp, topLeft);
+
+ temp.clone(topRight);
+ m.transform(temp, topRight);
+
+ temp.clone(bottomLeft);
+ m.transform(temp, bottomLeft);
+
+ temp.clone(bottomRight);
+ m.transform(temp, bottomRight);
+
+ camera.getTransform().getTranslation().clone().divide(zoom).addTo(cameraCenter, topLeft, topRight, bottomLeft, bottomRight);
+ }
+
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.octree.raytracer;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+
+/**
+ * Represents light source.
+ */
+public class LightSource {
+
+ /**
+ * Light source color.
+ */
+ public Color color;
+ /**
+ * Light source brightness.
+ */
+ public float brightness;
+ /**
+ * Light source location.
+ */
+ Point3D location;
+
+ /**
+ * Creates a light source at the given location with the specified color and brightness.
+ *
+ * @param location the position of the light source in world space
+ * @param color the color of the light
+ * @param Brightness the brightness multiplier (0.0 = off, 1.0 = full)
+ */
+ public LightSource(final Point3D location, final Color color,
+ final float Brightness) {
+ this.location = location;
+ this.color = color;
+ brightness = Brightness;
+ }
+
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.octree.raytracer;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+
+/**
+ * Represents a ray used for tracing through an {@link eu.svjatoslav.aukio.e3d.renderer.octree.OctreeVolume}.
+ *
+ * <p>A ray is defined by an {@link #origin} point and a {@link #direction} vector.
+ * After tracing through the octree, the intersection results are stored in the
+ * {@link #hitPoint}, {@link #hitCellSize}, and {@link #hitCellX}/{@link #hitCellY}/{@link #hitCellZ}
+ * fields, which are populated by the octree traversal algorithm.</p>
+ *
+ * @see RayTracer
+ * @see eu.svjatoslav.aukio.e3d.renderer.octree.OctreeVolume#traceCell(int, int, int, int, int, Ray)
+ */
+public class Ray {
+
+ /**
+ * The origin point of the ray (the starting position in world space).
+ */
+ public Point3D origin;
+
+ /**
+ * The direction vector of the ray. Does not need to be normalized;
+ * the octree traversal handles arbitrary direction magnitudes.
+ */
+ public Point3D direction;
+
+ /**
+ * The point in world space where the ray intersected an octree cell.
+ * Set by the octree traversal algorithm after a successful intersection.
+ */
+ public Point3D hitPoint;
+
+ /**
+ * The size (side length) of the octree cell that was hit.
+ * A value of 1 indicates a leaf cell at the finest resolution.
+ */
+ public int hitCellSize;
+
+ /**
+ * The x coordinate of the octree cell that was hit.
+ */
+ public int hitCellX;
+
+ /**
+ * The y coordinate of the octree cell that was hit.
+ */
+ public int hitCellY;
+
+ /**
+ * The z coordinate of the octree cell that was hit.
+ */
+ public int hitCellZ;
+
+ /**
+ * Creates a new ray with the specified origin and direction.
+ *
+ * @param origin the starting point of the ray
+ * @param direction the direction vector of the ray
+ */
+ public Ray(Point3D origin, Point3D direction) {
+ this.origin = origin;
+ this.direction = direction;
+ }
+
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.octree.raytracer;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.gui.ViewPanel;
+import eu.svjatoslav.aukio.e3d.renderer.octree.OctreeVolume;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+import eu.svjatoslav.aukio.e3d.renderer.raster.texture.Texture;
+
+import java.util.Vector;
+
+/**
+ * Ray tracing engine for rendering {@link OctreeVolume} scenes onto a {@link Texture}.
+ *
+ * <p>{@code RayTracer} implements {@link Runnable} and is designed to execute as a background
+ * task. It casts one ray per pixel through the camera's view frustum, tracing each ray
+ * into the octree volume to find intersections with solid cells. When a hit is found, the
+ * ray tracer computes per-pixel lighting by casting shadow rays from the hit point toward
+ * each {@link LightSource} along multiple surface-normal-offset directions (6 directions:
+ * +X, -X, +Y, -Y, +Z, -Z) to approximate diffuse illumination with soft shadows.</p>
+ *
+ * <p><b>Rendering pipeline</b></p>
+ * <ol>
+ * <li>The camera's view frustum corners are obtained via {@link RaytracingCamera#getCameraView()}.</li>
+ * <li>For each pixel, a primary ray is constructed from the camera center through the
+ * interpolated position on the view plane.</li>
+ * <li>The ray is traced through the octree using
+ * {@link OctreeVolume#traceCell(int, int, int, int, int, Ray)}.</li>
+ * <li>If a solid cell is hit, up to 6 shadow rays are cast toward each light source.
+ * If no shadow ray is occluded, the light's contribution is accumulated.</li>
+ * <li>The final pixel color is the cell's base color modulated by the accumulated light.</li>
+ * <li>Computed lighting is cached in the octree cell data ({@code cell3}) for reuse.</li>
+ * </ol>
+ *
+ * <p>Progress is reported periodically by invalidating the texture's mipmap cache and
+ * requesting a repaint on the {@link ViewPanel}, allowing partial results to be displayed
+ * while rendering continues.</p>
+ *
+ * @see OctreeVolume
+ * @see Ray
+ * @see LightSource
+ * @see RaytracingCamera
+ */
+public class RayTracer implements Runnable {
+
+ /**
+ * Minimum interval in milliseconds between progress updates (texture refresh and repaint).
+ */
+ private static final int PROGRESS_UPDATE_FREQUENCY_MILLIS = 1000;
+
+ /**
+ * The raytracing camera defining the viewpoint and view frustum for ray generation.
+ */
+ private final RaytracingCamera raytracingCamera;
+
+ /**
+ * The target texture where rendered pixels are written.
+ */
+ private final Texture texture;
+
+ /**
+ * The view panel used for triggering display repaints during progressive rendering.
+ */
+ private final ViewPanel viewPanel;
+
+ /**
+ * The octree volume to be ray-traced.
+ */
+ private final OctreeVolume octreeVolume;
+
+ /**
+ * The list of light sources used for illumination calculations.
+ */
+ private final Vector<LightSource> lights;
+
+ /**
+ * Counter tracking the number of light computations performed during the current render pass.
+ */
+ private int computedLights;
+
+ /**
+ * Creates a new ray tracer for the given scene configuration.
+ *
+ * @param texture the texture to render into; its primary bitmap dimensions
+ * determine the output resolution
+ * @param octreeVolume the octree volume containing the scene geometry
+ * @param lights the light sources to use for illumination
+ * @param raytracingCamera the raytracing camera defining the viewpoint
+ * @param viewPanel the view panel for triggering progress repaints
+ */
+ public RayTracer(final Texture texture, final OctreeVolume octreeVolume,
+ final Vector<LightSource> lights, final RaytracingCamera raytracingCamera,
+ final ViewPanel viewPanel) {
+
+ this.texture = texture;
+ this.octreeVolume = octreeVolume;
+ this.lights = lights;
+ this.raytracingCamera = raytracingCamera;
+ this.viewPanel = viewPanel;
+ }
+
+ /**
+ * Executes the ray tracing render pass.
+ *
+ * <p>Iterates over every pixel of the target texture, constructs a primary ray
+ * from the camera center through the view plane, traces it into the octree volume,
+ * and writes the resulting color. The texture is periodically refreshed to show
+ * progressive results.</p>
+ */
+ @Override
+ public void run() {
+ computedLights = 0;
+
+ // create camera
+
+ // Camera cam = new Camera(camCenter, upLeft, upRight, downLeft,
+ // downRight);
+
+ // add camera to the raytracing point
+ // Main.mainWorld.geometryCollection.addObject(cam);
+ // Main.mainWorld.compiledGeometry.compileGeometry(Main.mainWorld.geometryCollection);
+
+ final int width = texture.primaryBitmap.width;
+ final int height = texture.primaryBitmap.height;
+
+ final CameraView cameraView = raytracingCamera.getCameraView();
+
+ // calculate vertical vectors
+ final double x1p = cameraView.bottomLeft.x - cameraView.topLeft.x;
+ final double y1p = cameraView.bottomLeft.y - cameraView.topLeft.y;
+ final double z1p = cameraView.bottomLeft.z - cameraView.topLeft.z;
+
+ final double x2p = cameraView.bottomRight.x - cameraView.topRight.x;
+ final double y2p = cameraView.bottomRight.y - cameraView.topRight.y;
+ final double z2p = cameraView.bottomRight.z - cameraView.topRight.z;
+
+ long nextBitmapUpdate = System.currentTimeMillis()
+ + PROGRESS_UPDATE_FREQUENCY_MILLIS;
+
+ for (int y = 0; y < height; y++) {
+ final double cx1 = cameraView.topLeft.x + ((x1p * y) / height);
+ final double cy1 = cameraView.topLeft.y + ((y1p * y) / height);
+ final double cz1 = cameraView.topLeft.z + ((z1p * y) / height);
+
+ final double cx2 = cameraView.topRight.x + ((x2p * y) / height);
+ final double cy2 = cameraView.topRight.y + ((y2p * y) / height);
+ final double cz2 = cameraView.topRight.z + ((z2p * y) / height);
+
+ // calculate horizontal vector
+ final double x3p = cx2 - cx1;
+ final double y3p = cy2 - cy1;
+ final double z3p = cz2 - cz1;
+
+ for (int x = 0; x < width; x++) {
+ final double cx3 = cx1 + ((x3p * x) / width);
+ final double cy3 = cy1 + ((y3p * x) / width);
+ final double cz3 = cz1 + ((z3p * x) / width);
+
+ final Ray r = new Ray(
+ new Point3D(cameraView.cameraCenter.x,
+ cameraView.cameraCenter.y,
+ cameraView.cameraCenter.z),
+ new Point3D(
+ cx3 - cameraView.cameraCenter.x, cy3
+ - cameraView.cameraCenter.y, cz3
+ - cameraView.cameraCenter.z)
+ );
+ final int c = traceRay(r);
+
+ final Color color = new Color(c);
+ texture.primaryBitmap.drawPixel(x, y, color);
+ }
+
+ if (System.currentTimeMillis() > nextBitmapUpdate) {
+ nextBitmapUpdate = System.currentTimeMillis()
+ + PROGRESS_UPDATE_FREQUENCY_MILLIS;
+ texture.resetResampledBitmapCache();
+ viewPanel.repaintDuringNextViewUpdate();
+ }
+ }
+
+ texture.resetResampledBitmapCache();
+ viewPanel.repaintDuringNextViewUpdate();
+ }
+
+ /**
+ * Traces a single ray into the octree volume and computes the resulting pixel color.
+ *
+ * <p>If the ray intersects a solid cell, the method computes diffuse lighting by
+ * casting shadow rays from 6 surface-offset positions toward each light source.
+ * The lighting result is cached in the octree's {@code cell3} array to avoid
+ * redundant computation for the same cell.</p>
+ *
+ * @param ray the ray to trace (origin and direction must be set)
+ * @return the packed RGB color value (0xRRGGBB), or 0 if the ray hits nothing
+ */
+ private int traceRay(final Ray ray) {
+
+ final int intersectingCell = octreeVolume.traceCell(0, 0, 0,
+ octreeVolume.masterCellSize, 0, ray);
+
+ if (intersectingCell != -1) {
+ // if lighting not computed, compute it
+ if (octreeVolume.cell3[intersectingCell] == -1)
+ // if cell is larger than 1
+ if (ray.hitCellSize > 1) {
+ // break it up
+ octreeVolume.breakSolidCell(intersectingCell);
+ return traceRay(ray);
+ } else {
+ computedLights++;
+ float red = 30, green = 30, blue = 30;
+
+ for (final LightSource l : lights) {
+ final double xDist = (l.location.x - ray.hitCellX);
+ final double yDist = (l.location.y - ray.hitCellY);
+ final double zDist = (l.location.z - ray.hitCellZ);
+
+ double newRed = 0, newGreen = 0, newBlue = 0;
+ double tempRed, tempGreen, tempBlue;
+
+ double distance = Math.sqrt((xDist * xDist)
+ + (yDist * yDist) + (zDist * zDist));
+ distance = (distance / 3) + 1;
+
+ final Ray r1 = new Ray(
+ new Point3D(
+ ray.hitCellX,
+ ray.hitCellY - (float) 1.5,
+ ray.hitCellZ),
+
+ new Point3D((float) l.location.x - (float) ray.hitCellX, l.location.y
+ - (ray.hitCellY - (float) 1.5), (float) l.location.z
+ - (float) ray.hitCellZ)
+ );
+
+ final int rt1 = octreeVolume.traceCell(0, 0, 0,
+ octreeVolume.masterCellSize, 0, r1);
+
+ if (rt1 == -1) {
+ newRed = (l.color.r * l.brightness) / distance;
+ newGreen = (l.color.g * l.brightness) / distance;
+ newBlue = (l.color.b * l.brightness) / distance;
+ }
+
+ final Ray r2 = new Ray(
+ new Point3D(
+ ray.hitCellX - (float) 1.5,
+ ray.hitCellY, ray.hitCellZ),
+
+ new Point3D(
+ l.location.x - (ray.hitCellX - (float) 1.5), (float) l.location.y
+ - (float) ray.hitCellY, (float) l.location.z
+ - (float) ray.hitCellZ)
+ );
+
+ final int rt2 = octreeVolume.traceCell(0, 0, 0,
+ octreeVolume.masterCellSize, 0, r2);
+
+ if (rt2 == -1) {
+ tempRed = (l.color.r * l.brightness) / distance;
+ tempGreen = (l.color.g * l.brightness) / distance;
+ tempBlue = (l.color.b * l.brightness) / distance;
+
+ if (tempRed > newRed)
+ newRed = tempRed;
+ if (tempGreen > newGreen)
+ newGreen = tempGreen;
+ if (tempBlue > newBlue)
+ newBlue = tempBlue;
+ }
+
+ final Ray r3 = new Ray(
+ new Point3D(
+ ray.hitCellX, ray.hitCellY,
+ ray.hitCellZ - (float) 1.5),
+ new Point3D(
+ (float) l.location.x - (float) ray.hitCellX, (float) l.location.y
+ - (float) ray.hitCellY, l.location.z
+ - (ray.hitCellZ - (float) 1.5))
+ );
+
+ final int rt3 = octreeVolume.traceCell(0, 0, 0,
+ octreeVolume.masterCellSize, 0, r3);
+
+ if (rt3 == -1) {
+ tempRed = (l.color.r * l.brightness) / distance;
+ tempGreen = (l.color.g * l.brightness) / distance;
+ tempBlue = (l.color.b * l.brightness) / distance;
+ if (tempRed > newRed)
+ newRed = tempRed;
+ if (tempGreen > newGreen)
+ newGreen = tempGreen;
+ if (tempBlue > newBlue)
+ newBlue = tempBlue;
+ }
+
+ final Ray r4 = new Ray(
+ new Point3D(
+ ray.hitCellX,
+ ray.hitCellY + (float) 1.5,
+ ray.hitCellZ),
+
+ new Point3D(
+ (float) l.location.x - (float) ray.hitCellX, l.location.y
+ - (ray.hitCellY + (float) 1.5), (float) l.location.z
+ - (float) ray.hitCellZ)
+ );
+
+ final int rt4 = octreeVolume.traceCell(0, 0, 0,
+ octreeVolume.masterCellSize, 0, r4);
+
+ if (rt4 == -1) {
+ tempRed = (l.color.r * l.brightness) / distance;
+ tempGreen = (l.color.g * l.brightness) / distance;
+ tempBlue = (l.color.b * l.brightness) / distance;
+ if (tempRed > newRed)
+ newRed = tempRed;
+ if (tempGreen > newGreen)
+ newGreen = tempGreen;
+ if (tempBlue > newBlue)
+ newBlue = tempBlue;
+ }
+
+ final Ray r5 = new Ray(
+ new Point3D(
+ ray.hitCellX + (float) 1.5,
+ ray.hitCellY, ray.hitCellZ),
+
+ new Point3D(
+ l.location.x - (ray.hitCellX + (float) 1.5), (float) l.location.y
+ - (float) ray.hitCellY, (float) l.location.z
+ - (float) ray.hitCellZ)
+ );
+
+ final int rt5 = octreeVolume.traceCell(0, 0, 0,
+ octreeVolume.masterCellSize, 0, r5);
+
+ if (rt5 == -1) {
+ tempRed = (l.color.r * l.brightness) / distance;
+ tempGreen = (l.color.g * l.brightness) / distance;
+ tempBlue = (l.color.b * l.brightness) / distance;
+ if (tempRed > newRed)
+ newRed = tempRed;
+ if (tempGreen > newGreen)
+ newGreen = tempGreen;
+ if (tempBlue > newBlue)
+ newBlue = tempBlue;
+ }
+
+ final Ray r6 = new Ray(
+ new Point3D(
+ ray.hitCellX, ray.hitCellY,
+ ray.hitCellZ + (float) 1.5),
+
+ new Point3D(
+
+ (float) l.location.x - (float) ray.hitCellX, (float) l.location.y
+ - (float) ray.hitCellY, l.location.z
+ - (ray.hitCellZ + (float) 1.5)));
+
+ final int rt6 = octreeVolume.traceCell(0, 0, 0,
+ octreeVolume.masterCellSize, 0, r6);
+
+ if (rt6 == -1) {
+ tempRed = (l.color.r * l.brightness) / distance;
+ tempGreen = (l.color.g * l.brightness) / distance;
+ tempBlue = (l.color.b * l.brightness) / distance;
+ if (tempRed > newRed)
+ newRed = tempRed;
+ if (tempGreen > newGreen)
+ newGreen = tempGreen;
+ if (tempBlue > newBlue)
+ newBlue = tempBlue;
+ }
+ red += newRed;
+ green += newGreen;
+ blue += newBlue;
+
+ }
+
+ final int cellColor = octreeVolume.cell2[intersectingCell];
+
+ red = (red * ((cellColor & 0xFF0000) >> 16)) / 255;
+ green = (green * ((cellColor & 0xFF00) >> 8)) / 255;
+ blue = (blue * (cellColor & 0xFF)) / 255;
+
+ if (red > 255)
+ red = 255;
+ if (green > 255)
+ green = 255;
+ if (blue > 255)
+ blue = 255;
+
+ octreeVolume.cell3[intersectingCell] = (((int) red) << 16)
+ + (((int) green) << 8) + ((int) blue);
+
+ }
+ if (octreeVolume.cell3[intersectingCell] == 0)
+ return octreeVolume.cell2[intersectingCell];
+ return octreeVolume.cell3[intersectingCell];
+ }
+
+ // return (200 << 16) + (200 << 8) + 255;
+ return 0;
+ }
+
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.octree.raytracer;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.geometry.Camera;
+import eu.svjatoslav.aukio.e3d.math.Matrix3x3;
+import eu.svjatoslav.aukio.e3d.math.Transform;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.line.LineAppearance;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.TexturedRectangle;
+import eu.svjatoslav.aukio.e3d.renderer.raster.texture.Texture;
+
+import javax.imageio.ImageIO;
+import java.awt.*;
+import java.awt.image.BufferedImage;
+import java.io.IOException;
+import java.net.URL;
+
+/**
+ * Raytracing camera that renders a scene to a texture.
+ * It is represented on the scene as a textured rectangle showing the raytraced view.
+ */
+public class RaytracingCamera extends TexturedRectangle {
+
+ /** Size of the camera view in world units. */
+ public static final int SIZE = 100;
+ /** Size of the rendered image in pixels. */
+ public static final int IMAGE_SIZE = 500;
+ private final CameraView cameraView;
+
+ /**
+ * Creates a raytracing camera at the specified camera position.
+ *
+ * @param camera the camera to use for the view
+ * @param zoom the zoom level
+ */
+ public RaytracingCamera(final Camera camera, final double zoom) {
+ super(new Transform(camera.getTransform().getTranslation().clone()));
+ cameraView = new CameraView(camera, zoom);
+
+ computeCameraCoordinates(camera);
+
+ addWaitNotification(getTexture());
+ }
+
+ private void addWaitNotification(final Texture texture) {
+ // add hourglass icon
+ try {
+ final BufferedImage sprite = getSprite("eu/svjatoslav/aukio/e3d/examples/hourglass.png");
+ texture.graphics.drawImage(sprite, IMAGE_SIZE / 2,
+ (IMAGE_SIZE / 2) - 30, null);
+ } catch (final Exception ignored) {
+ }
+
+ // add "Please wait..." message
+ texture.graphics.setColor(java.awt.Color.WHITE);
+ texture.graphics.setFont(new Font("Monospaced", Font.PLAIN, 10));
+ texture.graphics.drawString("Please wait...", (IMAGE_SIZE / 2) - 20,
+ (IMAGE_SIZE / 2) + 30);
+ }
+
+ private void computeCameraCoordinates(final Camera camera) {
+ initialize(SIZE, SIZE, IMAGE_SIZE, IMAGE_SIZE, 3);
+
+ Point3D cameraCenter = new Point3D();
+
+ topLeft.setValues(cameraCenter.x, cameraCenter.y, cameraCenter.z + SIZE);
+ topRight.clone(topLeft);
+ bottomLeft.clone(topLeft);
+ bottomRight.clone(topLeft);
+
+ final float viewAngle = (float) .6;
+
+ topLeft.rotate(cameraCenter, -viewAngle, -viewAngle);
+ topRight.rotate(cameraCenter, viewAngle, -viewAngle);
+ bottomLeft.rotate(cameraCenter, -viewAngle, viewAngle);
+ bottomRight.rotate(cameraCenter, viewAngle, viewAngle);
+
+ final Matrix3x3 m = camera.getTransform().getRotation().invert().toMatrix3x3();
+ final Point3D temp = new Point3D();
+
+ temp.clone(topLeft);
+ temp.subtract(cameraCenter);
+ m.transform(temp, topLeft);
+ topLeft.add(cameraCenter);
+
+ temp.clone(topRight);
+ temp.subtract(cameraCenter);
+ m.transform(temp, topRight);
+ topRight.add(cameraCenter);
+
+ temp.clone(bottomLeft);
+ temp.subtract(cameraCenter);
+ m.transform(temp, bottomLeft);
+ bottomLeft.add(cameraCenter);
+
+ temp.clone(bottomRight);
+ temp.subtract(cameraCenter);
+ m.transform(temp, bottomRight);
+ bottomRight.add(cameraCenter);
+
+ final Color cameraColor = new Color(255, 255, 0, 255);
+ final LineAppearance appearance = new LineAppearance(2, cameraColor);
+
+ addShape(appearance.getLine(topLeft, topRight));
+ addShape(appearance.getLine(bottomLeft, bottomRight));
+ addShape(appearance.getLine(topLeft, bottomLeft));
+ addShape(appearance.getLine(topRight, bottomRight));
+
+ }
+
+ /**
+ * Returns the camera view used for ray tracing.
+ *
+ * @return the camera view
+ */
+ public CameraView getCameraView() {
+ return cameraView;
+ }
+
+ /**
+ * Loads a sprite image from the classpath.
+ *
+ * @param ref the resource path
+ * @return the loaded image
+ * @throws IOException if the image cannot be loaded
+ */
+ public BufferedImage getSprite(final String ref) throws IOException {
+ final URL url = this.getClass().getClassLoader().getResource(ref);
+ return ImageIO.read(url);
+ }
+
+}
--- /dev/null
+/**
+ * Ray tracer for rendering voxel data stored in an octree structure.
+ *
+ * <p>This package implements a ray tracing renderer that casts rays through an
+ * {@link eu.svjatoslav.aukio.e3d.renderer.octree.OctreeVolume} to produce rendered images
+ * of volumetric data. The ray tracer traverses the octree hierarchy for efficient
+ * intersection testing, skipping empty regions of space.</p>
+ *
+ * <p>Key classes:</p>
+ * <ul>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.octree.raytracer.RayTracer} - main ray tracing engine</li>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.octree.raytracer.RaytracingCamera} - camera configuration for ray generation</li>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.octree.raytracer.Ray} - represents a single ray cast through the volume</li>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.octree.raytracer.LightSource} - defines a light source for shading</li>
+ * </ul>
+ *
+ * @see eu.svjatoslav.aukio.e3d.renderer.octree.OctreeVolume the voxel data structure
+ */
+
+package eu.svjatoslav.aukio.e3d.renderer.octree.raytracer;
+
--- /dev/null
+/**
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ * <p>
+ *
+ * Various 3D renderers utilizing different rendering approaches.
+ *
+ */
+
+package eu.svjatoslav.aukio.e3d.renderer;
+
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster;
+
+/**
+ * RGBA color representation for the Aukio 3D engine.
+ *
+ * <p>This is the engine's own color class (not {@link java.awt.Color}). All color values
+ * use integer components in the range 0-255. The class provides predefined constants
+ * for common colors and several constructors for creating colors from different formats.</p>
+ *
+ * <p><b>Mutability:</b> Color fields are mutable to enable reuse during rendering
+ * (e.g., lighting calculations). This avoids allocating new Color instances per polygon.</p>
+ *
+ * <p><b>Usage examples:</b></p>
+ * <pre>{@code
+ * // Use predefined color constants
+ * Color red = Color.RED;
+ * Color semiTransparent = Color.hex("FF000080");
+ *
+ * // Create from hex string (recommended)
+ * Color hex6 = Color.hex("FF8800"); // RGB, fully opaque
+ * Color hex8 = Color.hex("FF880080"); // RGBA with alpha
+ * Color hex3 = Color.hex("F80"); // Short RGB format
+ *
+ * // Create from integer RGBA components (0-255)
+ * Color custom = new Color(100, 200, 50, 255);
+ *
+ * // Create from packed RGB integer
+ * Color packed = new Color(0xFF8800);
+ *
+ * // Modify existing color (avoids allocation)
+ * color.set(255, 128, 0, 255);
+ * }</pre>
+ *
+ * <p><b>Important:</b> Always use this class instead of {@link java.awt.Color} when
+ * working with the Aukio 3D engine's rendering pipeline.</p>
+ *
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon.SolidPolygon
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.line.Line
+ */
+public final class Color {
+
+ /**
+ * Fully opaque red (255, 0, 0).
+ */
+ public static final Color RED = new Color(255, 0, 0, 255);
+ /**
+ * Fully opaque green (0, 255, 0).
+ */
+ public static final Color GREEN = new Color(0, 255, 0, 255);
+ /**
+ * Fully opaque blue (0, 0, 255).
+ */
+ public static final Color BLUE = new Color(0, 0, 255, 255);
+ /**
+ * Fully opaque yellow (255, 255, 0).
+ */
+ public static final Color YELLOW = new Color(255, 255, 0, 255);
+ /**
+ * Fully opaque cyan (0, 255, 255).
+ */
+ public static final Color CYAN = new Color(0, 255, 255, 255);
+ /**
+ * Fully opaque magenta/purple (255, 0, 255).
+ */
+ public static final Color MAGENTA = new Color(255, 0, 255, 255);
+ /**
+ * Fully opaque white (255, 255, 255).
+ */
+ public static final Color WHITE = new Color(255, 255, 255, 255);
+ /**
+ * Fully opaque black (0, 0, 0).
+ */
+ public static final Color BLACK = new Color(0, 0, 0, 255);
+ /**
+ * Fully opaque purple/magenta (255, 0, 255).
+ */
+ public static final Color PURPLE = new Color(255, 0, 255, 255);
+ /**
+ * Fully transparent (alpha = 0).
+ */
+ public static final Color TRANSPARENT = new Color(0, 0, 0, 0);
+ /**
+ * Red component. 0-255.
+ */
+ public int r;
+ /**
+ * Green component. 0-255.
+ */
+ public int g;
+ /**
+ * Blue component. 0-255.
+ */
+ public int b;
+ /**
+ * Alpha component.
+ * 0 - transparent.
+ * 255 - opaque.
+ */
+ public int a;
+ private java.awt.Color cachedAwtColor;
+
+ /**
+ * Creates a black, fully opaque color (0, 0, 0, 255).
+ */
+ public Color() {
+ this.r = 0;
+ this.g = 0;
+ this.b = 0;
+ this.a = 255;
+ }
+
+ /**
+ * Creates a copy of the given color.
+ *
+ * @param parentColor the color to copy
+ */
+ public Color(final Color parentColor) {
+ r = parentColor.r;
+ g = parentColor.g;
+ b = parentColor.b;
+ a = parentColor.a;
+ }
+
+ /**
+ * Creates a color from floating-point RGBA components in the range 0.0 to 1.0.
+ * Values are internally converted to 0-255 integer range and clamped.
+ *
+ * @param r red component (0.0 = none, 1.0 = full)
+ * @param g green component (0.0 = none, 1.0 = full)
+ * @param b blue component (0.0 = none, 1.0 = full)
+ * @param a alpha component (0.0 = transparent, 1.0 = opaque)
+ */
+ public Color(final double r, final double g, final double b, final double a) {
+ this.r = clamp((int) (r * 255d));
+ this.g = clamp((int) (g * 255d));
+ this.b = clamp((int) (b * 255d));
+ this.a = clamp((int) (a * 255d));
+ }
+
+ /**
+ * Creates a color from a hexadecimal string.
+ *
+ * @param colorHexCode color code in hex format.
+ * Supported formats are:
+ * <pre>
+ * RGB
+ * RGBA
+ * RRGGBB
+ * RRGGBBAA
+ * </pre>
+ */
+ public Color(String colorHexCode) {
+ switch (colorHexCode.length()) {
+ case 3:
+ r = parseHexSegment(colorHexCode, 0, 1) * 16;
+ g = parseHexSegment(colorHexCode, 1, 1) * 16;
+ b = parseHexSegment(colorHexCode, 2, 1) * 16;
+ a = 255;
+ return;
+
+ case 4:
+ r = parseHexSegment(colorHexCode, 0, 1) * 16;
+ g = parseHexSegment(colorHexCode, 1, 1) * 16;
+ b = parseHexSegment(colorHexCode, 2, 1) * 16;
+ a = parseHexSegment(colorHexCode, 3, 1) * 16;
+ return;
+
+ case 6:
+ r = parseHexSegment(colorHexCode, 0, 2);
+ g = parseHexSegment(colorHexCode, 2, 2);
+ b = parseHexSegment(colorHexCode, 4, 2);
+ a = 255;
+ return;
+
+ case 8:
+ r = parseHexSegment(colorHexCode, 0, 2);
+ g = parseHexSegment(colorHexCode, 2, 2);
+ b = parseHexSegment(colorHexCode, 4, 2);
+ a = parseHexSegment(colorHexCode, 6, 2);
+ return;
+ default:
+ throw new IllegalArgumentException("Unsupported color code: " + colorHexCode);
+ }
+ }
+
+ /**
+ * Creates a fully opaque color from a packed RGB integer.
+ *
+ * <p>The integer is interpreted as {@code 0xRRGGBB}, where the upper 8 bits
+ * are the red channel, the middle 8 bits are green, and the lower 8 bits are blue.</p>
+ *
+ * @param rgb packed RGB value (e.g. {@code 0xFF8800} for orange)
+ */
+ public Color(final int rgb) {
+ r = (rgb & 0xFF0000) >> 16;
+ g = (rgb & 0xFF00) >> 8;
+ b = rgb & 0xFF;
+ a = 255;
+ }
+
+ /**
+ * Creates a fully opaque color from RGB integer components (0-255).
+ *
+ * @param r red component (0-255)
+ * @param g green component (0-255)
+ * @param b blue component (0-255)
+ */
+ public Color(final int r, final int g, final int b) {
+ this(r, g, b, 255);
+ }
+
+ /**
+ * Creates a color from RGBA integer components (0-255).
+ * Values outside 0-255 are clamped.
+ *
+ * @param r red component (0-255)
+ * @param g green component (0-255)
+ * @param b blue component (0-255)
+ * @param a alpha component (0 = transparent, 255 = opaque)
+ */
+ public Color(final int r, final int g, final int b, final int a) {
+ this.r = clamp(r);
+ this.g = clamp(g);
+ this.b = clamp(b);
+ this.a = clamp(a);
+ }
+
+ /**
+ * Creates a color from a hexadecimal string.
+ *
+ * <p>Supported formats:</p>
+ * <ul>
+ * <li>{@code RGB} - 3 hex digits, fully opaque</li>
+ * <li>{@code RGBA} - 4 hex digits</li>
+ * <li>{@code RRGGBB} - 6 hex digits, fully opaque</li>
+ * <li>{@code RRGGBBAA} - 8 hex digits</li>
+ * </ul>
+ *
+ * @param hex hex color code
+ * @return a new Color instance
+ */
+ public static Color hex(final String hex) {
+ return new Color(hex);
+ }
+
+ /**
+ * Clamps a value to the valid color component range (0-255).
+ *
+ * @param value the value to clamp
+ * @return the clamped value
+ */
+ public static int clamp(final int value) {
+ if (value < 0) return 0;
+ if (value > 255) return 255;
+ return value;
+ }
+
+ private int parseHexSegment(String hexString, int start, int length) {
+ return Integer.parseInt(hexString.substring(start, start + length), 16);
+ }
+
+ /**
+ * Returns {@code true} if this color is fully transparent (alpha = 0).
+ *
+ * @return {@code true} if the alpha component is zero
+ */
+ public boolean isTransparent() {
+ return a == 0;
+ }
+
+ /**
+ * Sets all color components at once.
+ *
+ * <p>Values outside 0-255 are clamped. This method invalidates any cached
+ * AWT color, so the next call to {@link #toAwtColor()} will create a new one.</p>
+ *
+ * @param r red component (0-255)
+ * @param g green component (0-255)
+ * @param b blue component (0-255)
+ * @param a alpha component (0-255)
+ * @return this Color for chaining
+ */
+ public Color set(final int r, final int g, final int b, final int a) {
+ this.r = clamp(r);
+ this.g = clamp(g);
+ this.b = clamp(b);
+ this.a = clamp(a);
+ cachedAwtColor = null;
+ return this;
+ }
+
+ /**
+ * Copies values from another color.
+ *
+ * @param other the color to copy from
+ * @return this Color for chaining
+ */
+ public Color set(final Color other) {
+ this.r = other.r;
+ this.g = other.g;
+ this.b = other.b;
+ this.a = other.a;
+ cachedAwtColor = null;
+ return this;
+ }
+
+ /**
+ * Converts this color to a {@link java.awt.Color} instance for use with
+ * Java AWT/Swing graphics APIs.
+ *
+ * @return the equivalent {@link java.awt.Color}
+ */
+ public java.awt.Color toAwtColor() {
+ if (cachedAwtColor == null)
+ cachedAwtColor = new java.awt.Color(r, g, b, a);
+ return cachedAwtColor;
+ }
+
+ /**
+ * Converts this color to a packed ARGB integer as used by {@link java.awt.Color#getRGB()}.
+ *
+ * @return packed ARGB integer representation
+ */
+ public int toInt() {
+ return (a << 24) | (r << 16) | (g << 8) | b;
+ }
+
+ @Override
+ public boolean equals(Object o) {
+ if (this == o) return true;
+ if (o == null || getClass() != o.getClass()) return false;
+
+ Color color = (Color) o;
+
+ if (r != color.r) return false;
+ if (g != color.g) return false;
+ if (b != color.b) return false;
+ return a == color.a;
+ }
+
+ @Override
+ public int hashCode() {
+ int result = r;
+ result = 31 * result + g;
+ result = 31 * result + b;
+ result = 31 * result + a;
+ return result;
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster;
+
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * Statistics for frustum culling, tracking composite-level culling efficiency.
+ *
+ * <p>Updated each frame during the rendering pipeline:</p>
+ * <ul>
+ * <li>{@link #totalComposites} - incremented before each composite's frustum test</li>
+ * <li>{@link #culledComposites} - incremented when a composite fails the frustum test</li>
+ * </ul>
+ *
+ * <p>Thread safety: counters are {@link AtomicInteger} because the parallel
+ * transform phase increments them from multiple worker threads.</p>
+ *
+ * <p>Displayed in the {@link eu.svjatoslav.aukio.e3d.gui.DeveloperToolsPanel} to help developers understand
+ * culling efficiency and optimize scene graphs.</p>
+ *
+ * @see eu.svjatoslav.aukio.e3d.gui.DeveloperToolsPanel
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.Frustum
+ */
+public class CullingStatistics {
+
+ /**
+ * Total number of composite shapes tested against the frustum this frame.
+ * Incremented before each composite's AABB frustum test.
+ * Does not include the root composite (which is never frustum-tested).
+ */
+ public final AtomicInteger totalComposites = new AtomicInteger(0);
+
+ /**
+ * Number of composite shapes that were entirely outside the frustum and skipped.
+ * When a composite is culled, all its children (shapes and nested composites)
+ * are skipped without individual testing.
+ */
+ public final AtomicInteger culledComposites = new AtomicInteger(0);
+
+ /**
+ * Resets all statistics to zero.
+ * Called at the start of each frame before computing new statistics.
+ */
+ public void reset() {
+ totalComposites.set(0);
+ culledComposites.set(0);
+ }
+
+ /**
+ * Returns the percentage of composites that were culled.
+ *
+ * @return the culled percentage (0-100), or 0 if there are no composites
+ */
+ public double getCulledPercentage() {
+ final int total = totalComposites.get();
+ if (total == 0) {
+ return 0.0;
+ }
+ return 100.0 * culledComposites.get() / total;
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster;
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.geometry.Box;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.Plane;
+
+import eu.svjatoslav.aukio.e3d.geometry.Camera;
+
+/**
+ * View frustum for frustum culling - eliminates objects outside the camera's view.
+ *
+ * <p>The frustum is a truncated pyramid-shaped volume that represents everything
+ * the camera can see. Objects completely outside this volume can be skipped
+ * during rendering, significantly improving performance for large scenes.</p>
+ *
+ * <p><b>Frustum planes:</b></p>
+ * <ul>
+ * <li>Left, Right, Top, Bottom - define the viewport edges</li>
+ * <li>Near - closest visible distance from camera</li>
+ * <li>Far - farthest visible distance from camera</li>
+ * </ul>
+ *
+ * <p><b>Usage:</b></p>
+ * <pre>{@code
+ * Frustum frustum = new Frustum();
+ * frustum.update(camera, screenWidth, screenHeight);
+ *
+ * Box objectBounds = shape.getBoundingBox();
+ * if (frustum.intersectsAABB(objectBounds)) {
+ * // Object is potentially visible - render it
+ * } else {
+ * // Object outside frustum - skip rendering
+ * }
+ * }</pre>
+ *
+ * <p><b>AABB intersection algorithm:</b></p>
+ * <p>Uses the optimized "P-vertex" approach: for each plane, we test only
+ * the AABB corner most aligned with the plane normal. If this corner is
+ * behind the plane, the entire AABB is outside the frustum.</p>
+ *
+ * @see Box axis-aligned bounding box for culling tests
+ * @see Camera provides position and orientation for frustum computation
+ */
+public class Frustum {
+
+ /**
+ * Index for the left clipping plane.
+ */
+ public static final int LEFT = 0;
+ /**
+ * Index for the right clipping plane.
+ */
+ public static final int RIGHT = 1;
+ /**
+ * Index for the top clipping plane.
+ */
+ public static final int TOP = 2;
+ /**
+ * Index for the bottom clipping plane.
+ */
+ public static final int BOTTOM = 3;
+ /**
+ * Index for the near clipping plane.
+ */
+ public static final int NEAR = 4;
+ /**
+ * Index for the far clipping plane.
+ */
+ public static final int FAR = 5;
+
+ /**
+ * The six clipping planes defining the frustum volume.
+ * Each plane is stored as (normal, distance) in Hesse normal form.
+ * Planes are in world space coordinates.
+ */
+ private final Plane[] planes = new Plane[6];
+
+ /**
+ * Default near plane distance from camera (in world units).
+ * Objects closer than this are culled.
+ */
+ private double nearDistance = 1.0;
+
+ /**
+ * Default far plane distance from camera (in world units).
+ * Objects farther than this are culled.
+ */
+ private double farDistance = 10000.0;
+
+ /**
+ * Creates a new frustum with uninitialized planes.
+ * Call {@link #update} before using for culling.
+ */
+ public Frustum() {
+ for (int i = 0; i < 6; i++) {
+ planes[i] = new Plane(new Point3D(0, 0, 1), 0);
+ }
+ }
+
+ /**
+ * Updates the frustum planes in view space (camera at origin, looking along +Z).
+ *
+ * <p>This method should be called once per frame before rendering, after the
+ * camera position and orientation have been updated.</p>
+ *
+ * <p><b>View space coordinate system:</b></p>
+ * <ul>
+ * <li>Camera at origin (0, 0, 0)</li>
+ * <li>Forward = +Z axis (looking into the screen)</li>
+ * <li>Right = +X axis</li>
+ * <li>Up = -Y axis (since Y-down means smaller Y is higher visually)</li>
+ * </ul>
+ *
+ * <p><b>Plane normals point INTO the frustum</b> (toward the visible volume).
+ * A point is inside if dot(normal, point) >= distance for all planes.</p>
+ *
+ * <p><b>FOV calculation:</b> The Aukio 3D engine uses projectionScale = width/3.
+ * This means tan(halfHFOV) = (width/2) / projectionScale = 1.5, giving a
+ * horizontal FOV of approximately 112 degrees.</p>
+ *
+ * @param camera the camera (used only for aspect ratio derivation from width/height)
+ * @param width the viewport width in pixels (defines projectionScale)
+ * @param height the viewport height in pixels (used for vertical FOV)
+ */
+ public void update(final Camera camera, final int width, final int height) {
+ // Frustum is computed in VIEW SPACE (camera at origin, looking along +Z)
+ // This matches the coordinate system after applying camera transforms
+
+ // Aukio 3D uses projectionScale = width/3
+ // tan(halfFOV) = (halfSize) / projectionScale
+ final double projectionScale = width / 3.0;
+ final double tanHalfHFOV = (width / 2.0) / projectionScale; // = 1.5 (very wide FOV)
+ final double tanHalfVFOV = (height / 2.0) / projectionScale; // depends on aspect ratio
+
+ // Compute cosine and sine of half-FOV angles
+ // cosHalfFOV = 1 / sqrt(1 + tanHalfFOV^2)
+ // sinHalfFOV = tanHalfFOV * cosHalfFOV
+ final double cosHalfHFOV = 1.0 / Math.sqrt(1.0 + tanHalfHFOV * tanHalfHFOV);
+ final double sinHalfHFOV = tanHalfHFOV * cosHalfHFOV;
+ final double cosHalfVFOV = 1.0 / Math.sqrt(1.0 + tanHalfVFOV * tanHalfVFOV);
+ final double sinHalfVFOV = tanHalfVFOV * cosHalfVFOV;
+
+ // Near and far distances
+ nearDistance = 1.0;
+ farDistance = 10000.0;
+
+ // All side planes pass through origin (camera position in view space)
+ // Plane equation: dot(normal, point) >= distance means inside
+
+ // Left plane: inward normal pointing right-forward
+ // Bounds: x >= -tanHalfHFOV * z (to the right of left edge)
+ planes[LEFT].normal = new Point3D(cosHalfHFOV, 0, sinHalfHFOV);
+ planes[LEFT].distance = 0;
+
+ // Right plane: inward normal pointing left-forward
+ // Bounds: x <= tanHalfHFOV * z (to the left of right edge)
+ planes[RIGHT].normal = new Point3D(-cosHalfHFOV, 0, sinHalfHFOV);
+ planes[RIGHT].distance = 0;
+
+ // Top plane: inward normal pointing down-forward (Y-down system, top is smaller Y)
+ // Bounds: y <= tanHalfVFOV * z (below top edge, smaller Y)
+ planes[TOP].normal = new Point3D(0, -cosHalfVFOV, sinHalfVFOV);
+ planes[TOP].distance = 0;
+
+ // Bottom plane: inward normal pointing up-forward (larger Y is below)
+ // Bounds: y >= -tanHalfVFOV * z (above bottom edge, larger Y)
+ planes[BOTTOM].normal = new Point3D(0, cosHalfVFOV, sinHalfVFOV);
+ planes[BOTTOM].distance = 0;
+
+ // Near plane: inward normal pointing forward (+Z)
+ // Bounds: z >= nearDistance (in front of near plane)
+ planes[NEAR].normal = new Point3D(0, 0, 1);
+ planes[NEAR].distance = nearDistance;
+
+ // Far plane: inward normal pointing backward (-Z)
+ // Bounds: z <= farDistance (behind far plane)
+ planes[FAR].normal = new Point3D(0, 0, -1);
+ planes[FAR].distance = -farDistance;
+ }
+
+ /**
+ * Tests whether an axis-aligned bounding box intersects the frustum.
+ *
+ * <p>This is a conservative test: returns {@code true} if the box is
+ * potentially visible (inside or partially inside the frustum), and
+ * {@code false} only if the box is completely outside all frustum planes.</p>
+ *
+ * <p><b>Optimized algorithm:</b></p>
+ * <p>For each plane, we test only the AABB corner most aligned with the
+ * plane normal (the "P-vertex"). If this corner is behind the plane,
+ * the entire AABB must be outside the frustum.</p>
+ *
+ * @param box the axis-aligned bounding box to test (in view space coordinates)
+ * @return {@code true} if the box intersects or is inside the frustum,
+ * {@code false} if completely outside
+ */
+ public boolean intersectsAABB(final Box box) {
+ // Get box min/max for each axis
+ final double minX = box.getMinX();
+ final double maxX = box.getMaxX();
+ final double minY = box.getMinY();
+ final double maxY = box.getMaxY();
+ final double minZ = box.getMinZ();
+ final double maxZ = box.getMaxZ();
+
+ for (int i = 0; i < 6; i++) {
+ final Plane plane = planes[i];
+ final Point3D n = plane.normal;
+ final double d = plane.distance;
+
+ // Find the P-vertex: the corner most aligned with the plane normal
+ // If normal component is positive, use max; if negative, use min
+ final double px = (n.x > 0) ? maxX : minX;
+ final double py = (n.y > 0) ? maxY : minY;
+ final double pz = (n.z > 0) ? maxZ : minZ;
+
+ // Test if P-vertex is outside the frustum (behind the plane)
+ // For inward-pointing normals: inside = dot(N,P) >= distance
+ // So outside = dot(N,P) < distance
+ if (n.x * px + n.y * py + n.z * pz < d) {
+ return false; // AABB entirely outside this plane
+ }
+ }
+
+ return true; // AABB intersects or inside all planes
+ }
+
+ /**
+ * Returns the near clipping plane distance.
+ *
+ * @return the near distance in world units
+ */
+ public double getNearDistance() {
+ return nearDistance;
+ }
+
+ /**
+ * Returns the far clipping plane distance.
+ *
+ * @return the far distance in world units
+ */
+ public double getFarDistance() {
+ return farDistance;
+ }
+
+ /**
+ * Sets the near and far clipping distances.
+ *
+ * @param near the near plane distance (objects closer are culled)
+ * @param far the far plane distance (objects farther are culled)
+ */
+ public void setClipDistances(final double near, final double far) {
+ this.nearDistance = near;
+ this.farDistance = far;
+ }
+
+ /**
+ * Returns a specific frustum plane for debugging or advanced usage.
+ *
+ * @param planeIndex one of LEFT, RIGHT, TOP, BOTTOM, NEAR, FAR
+ * @return the plane at the specified index
+ */
+ public Plane getPlane(final int planeIndex) {
+ return planes[planeIndex];
+ }
+}
\ No newline at end of file
--- /dev/null
+package eu.svjatoslav.aukio.e3d.renderer.raster;
+
+import java.util.Arrays;
+import java.util.concurrent.atomic.AtomicLong;
+
+/**
+ * Hierarchical depth pyramid for whole-block occlusion culling
+ * (Hi-Z). Built from the just-painted frame's depth buffer; queried
+ * during the NEXT frame's transform to skip blocks that are fully
+ * hidden behind what was drawn last frame.
+ *
+ * <p>Semantics: each tile stores the MINIMUM w (= 1/z, i.e. the
+ * FARTHEST written depth) over its pixels. A block whose nearest
+ * possible point (max w over its AABB corners) is farther than a
+ * tile's farthest written depth is behind something at every written
+ * pixel of that tile — and tiles with any unwritten (sky) pixel hold
+ * -infinity and never occlude. That makes the test conservative: it
+ * may keep a hidden block, it never culls a visible one — under a
+ * static camera. (The first version max-pooled, storing the NEAREST
+ * depth per tile; that culled houses visible BETWEEN nearer tree
+ * trunks — per-pixel gaps inside a tile are invisible to a max.)
+ * Camera motion reuses the stale pyramid, which can cull a
+ * newly-visible block wrongly; the block's pixels then contain far
+ * background depth, so the next frame's pyramid no longer occludes
+ * it — wrong culls self-heal in one frame (sanctioned design
+ * concession), and the query margin absorbs small-motion
+ * parallax.</p>
+ *
+ * <p>Empty tiles (never depth-written) store -infinity and never
+ * occlude, so the first frame after startup (or after any pass that
+ * leaves the pyramid unbuilt) culls nothing.</p>
+ *
+ * <p>Knobs: {@code -Daukio.hiz=false} disables culling (build still
+ * happens — it is cheap — so flipping the flag needs no warm-up);
+ * {@code -Daukio.hiz.margin=0.02} sets the relative w-space safety
+ * margin against parallax between frames.</p>
+ */
+public final class HiZPyramid {
+
+ /** Level-0 tile edge in pixels; level i tiles cover TILE*2^i px. */
+ private static final int TILE = 8;
+
+ private static final boolean ENABLED = Boolean.parseBoolean(
+ System.getProperty("aukio.hiz", "true"));
+ private static final double MARGIN = Double.parseDouble(
+ System.getProperty("aukio.hiz.margin", "0.02"));
+
+ /** Blocks occlusion-tested this process (telemetry). */
+ public final AtomicLong blocksTested = new AtomicLong();
+ /** Blocks culled as fully occluded (telemetry). */
+ public final AtomicLong blocksCulled = new AtomicLong();
+
+ private float[] tiles = new float[0];
+ private int[] levelOff = new int[0];
+ private int[] levelW = new int[0];
+ private int[] levelH = new int[0];
+ private int levels;
+ private int bufW = -1, bufH = -1;
+
+ /** Rebuilds the pyramid from a freshly painted depth buffer. */
+ public synchronized void buildFrom(final float[] depth,
+ final int width, final int height) {
+ if (width != bufW || height != bufH) {
+ allocate(width, height);
+ }
+
+ // Level 0: min-pool depth into TILE x TILE tiles. Depth
+ // outside the painted area is -infinity (cleared), so a tile
+ // with any unpainted pixel never occludes.
+ final int w0 = levelW[0], h0 = levelH[0];
+ final int off0 = levelOff[0];
+ for (int ty = 0; ty < h0; ty++) {
+ final int yEnd = Math.min((ty + 1) * TILE, height);
+ for (int tx = 0; tx < w0; tx++) {
+ final int xEnd = Math.min((tx + 1) * TILE, width);
+ float m = Float.POSITIVE_INFINITY;
+ for (int y = ty * TILE; y < yEnd; y++) {
+ final int row = y * width;
+ for (int x = tx * TILE; x < xEnd; x++)
+ if (depth[row + x] < m)
+ m = depth[row + x];
+ }
+ tiles[off0 + ty * w0 + tx] = m;
+ }
+ }
+
+ // Higher levels: min of 2x2 children.
+ for (int l = 1; l < levels; l++) {
+ final int pw = levelW[l - 1], ph = levelH[l - 1];
+ final int poff = levelOff[l - 1];
+ final int cw = levelW[l], ch = levelH[l];
+ final int coff = levelOff[l];
+ for (int ty = 0; ty < ch; ty++)
+ for (int tx = 0; tx < cw; tx++) {
+ float m = Float.POSITIVE_INFINITY;
+ for (int dy = 0; dy < 2; dy++)
+ for (int dx = 0; dx < 2; dx++) {
+ final int sx = tx * 2 + dx, sy = ty * 2 + dy;
+ if (sx < pw && sy < ph) {
+ final float v = tiles[poff + sy * pw + sx];
+ if (v < m)
+ m = v;
+ }
+ }
+ tiles[coff + ty * cw + tx] = m;
+ }
+ }
+ }
+
+ /**
+ * Conservative whole-block occlusion test.
+ *
+ * @param x1..y2 screen-space AABB of the block (will be clamped
+ * to the buffer; a fully off-screen box returns
+ * false)
+ * @param nearestW the block's nearest possible depth = MAX 1/z
+ * over its corners
+ * @return true when the block is certainly hidden behind last
+ * frame's occluders (within the parallax margin)
+ */
+ public synchronized boolean occluded(final double x1, final double y1,
+ final double x2, final double y2,
+ final double nearestW) {
+ if (!ENABLED || levels == 0)
+ return false;
+
+ int bx1 = (int) Math.floor(x1), by1 = (int) Math.floor(y1);
+ int bx2 = (int) Math.ceil(x2), by2 = (int) Math.ceil(y2);
+ if (bx1 < 0) bx1 = 0;
+ if (by1 < 0) by1 = 0;
+ if (bx2 >= bufW) bx2 = bufW - 1;
+ if (by2 >= bufH) by2 = bufH - 1;
+ if (bx1 > bx2 || by1 > by2)
+ return false;
+
+ // Coarsest level where the box still covers <= 2 tiles per axis.
+ int level = 0;
+ while (level + 1 < levels) {
+ final int s = TILE << (level + 1);
+ final int tw = (bx2 / s) - (bx1 / s) + 1;
+ final int th = (by2 / s) - (by1 / s) + 1;
+ if (tw > 2 || th > 2)
+ break;
+ level++;
+ }
+
+ final int s = TILE << level;
+ final int tx1 = bx1 / s, ty1 = by1 / s;
+ final int tx2 = bx2 / s, ty2 = by2 / s;
+ final int w = levelW[level], off = levelOff[level];
+
+ float minStored = Float.POSITIVE_INFINITY;
+ for (int ty = ty1; ty <= ty2; ty++)
+ for (int tx = tx1; tx <= tx2; tx++) {
+ final float v = tiles[off + ty * w + tx];
+ if (v < minStored)
+ minStored = v;
+ }
+
+ // Occluded only when the block's nearest point is clearly
+ // behind the farthest written depth in the range; the
+ // relative margin absorbs parallax between frames.
+ return nearestW < minStored * (1.0 - MARGIN);
+ }
+
+ private void allocate(final int width, final int height) {
+ bufW = width;
+ bufH = height;
+ int lw = (width + TILE - 1) / TILE;
+ int lh = (height + TILE - 1) / TILE;
+ int count = 0;
+ levels = 0;
+ while (true) {
+ levels++;
+ count += lw * lh;
+ if (lw == 1 && lh == 1)
+ break;
+ lw = Math.max(1, (lw + 1) / 2);
+ lh = Math.max(1, (lh + 1) / 2);
+ }
+ tiles = new float[count];
+ levelOff = new int[levels];
+ levelW = new int[levels];
+ levelH = new int[levels];
+ lw = (width + TILE - 1) / TILE;
+ lh = (height + TILE - 1) / TILE;
+ int off = 0;
+ for (int l = 0; l < levels; l++) {
+ levelOff[l] = off;
+ levelW[l] = lw;
+ levelH[l] = lh;
+ off += lw * lh;
+ lw = Math.max(1, (lw + 1) / 2);
+ lh = Math.max(1, (lh + 1) / 2);
+ }
+ Arrays.fill(tiles, Float.NEGATIVE_INFINITY);
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster;
+
+import java.util.Queue;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ConcurrentLinkedQueue;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Future;
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * Coordinates the non-blocking parallel transform fork for one frame.
+ *
+ * <p>Every composite whose render list exceeds the parallel threshold (at
+ * ANY nesting level, not just the root) splits its children into chunks and
+ * submits chunk tasks here instead of transforming them serially. Chunk
+ * tasks never block on other tasks, so a fixed-size pool cannot starve;
+ * only the orchestrating render thread waits, in {@link #drainAndMergeInto}.
+ * This is what makes recursive decomposition safe: a nested heavy composite
+ * reached inside a chunk task forks its own children into the same queue
+ * and returns immediately.</p>
+ *
+ * <p>Merge order is irrelevant: the depth sort that follows the transform
+ * phase is deterministic on (Z, shapeId).</p>
+ *
+ * <p>Lifecycle: created by {@code ShapeCollection.transformShapes()} when a
+ * transform executor is available, published on the rendering context for
+ * the duration of the root transform, drained and discarded before the
+ * sort phase.</p>
+ */
+public final class ParallelTransformCoordinator {
+
+ private final ExecutorService executor;
+ private final Queue<Future<RenderAggregator>> futures = new ConcurrentLinkedQueue<>();
+ private final AtomicInteger submittedTaskCount = new AtomicInteger();
+
+ /**
+ * Shared pools of chunk-task scratch objects. Coordinators are
+ * created per render pass, so the pools are static — otherwise
+ * reuse would never survive the next pass. A pooled aggregator's
+ * queue list keeps its capacity (reset() does not shrink), and a
+ * pooled TransformStack keeps its fixed arrays, so steady-state
+ * frames allocate neither the 9.6 KB stack per chunk nor the
+ * doubling-copy chain of every chunk's queue.
+ */
+ private static final Queue<eu.svjatoslav.aukio.e3d.math.TransformStack>
+ STACK_POOL = new ConcurrentLinkedQueue<>();
+ private static final Queue<RenderAggregator>
+ AGGREGATOR_POOL = new ConcurrentLinkedQueue<>();
+
+ /**
+ * Borrows a pooled transform stack preloaded with {@code source}'s
+ * composed state. Must be returned with {@link #returnStack} when
+ * the chunk task finishes.
+ *
+ * @param source stack to copy into the borrowed instance
+ * @return a stack, possibly reused from a previous frame
+ */
+ public eu.svjatoslav.aukio.e3d.math.TransformStack borrowStack(
+ final eu.svjatoslav.aukio.e3d.math.TransformStack source) {
+ eu.svjatoslav.aukio.e3d.math.TransformStack stack = STACK_POOL.poll();
+ if (stack == null)
+ stack = new eu.svjatoslav.aukio.e3d.math.TransformStack();
+ stack.loadFrom(source);
+ return stack;
+ }
+
+ /**
+ * Returns a borrowed stack to the pool. The caller must not touch
+ * it afterwards.
+ *
+ * @param stack the borrowed stack
+ */
+ public void returnStack(
+ final eu.svjatoslav.aukio.e3d.math.TransformStack stack) {
+ STACK_POOL.offer(stack);
+ }
+
+ /**
+ * Borrows a pooled chunk aggregator (reset, but with its queue
+ * capacity intact from previous frames).
+ *
+ * @return an aggregator, possibly reused from a previous frame
+ */
+ public RenderAggregator borrowAggregator() {
+ final RenderAggregator aggregator = AGGREGATOR_POOL.poll();
+ return aggregator != null ? aggregator : new RenderAggregator();
+ }
+
+ /**
+ * Frame parity captured at construction, stamped onto recorded
+ * timeline intervals so overlapping frames keep distinct colors.
+ */
+ private final int traceParity = eu.svjatoslav.aukio.e3d.diag.ThreadActivityRecorder.frameParity();
+
+ /**
+ * Frame-wide cap on chunk tasks. Deep hierarchies of heavy composites
+ * would otherwise fork geometrically (each fork targets cores*4 tasks);
+ * past the cap, composites transform serially inline. The cap is
+ * generous enough that realistic scenes never hit it.
+ */
+ private final int maxTasks = Runtime.getRuntime().availableProcessors() * 64;
+
+ public ParallelTransformCoordinator(final ExecutorService executor) {
+ this.executor = executor;
+ }
+
+ /**
+ * Reserves budget for {@code count} chunk tasks. Returns false when the
+ * frame-wide cap would be exceeded; the caller must then transform
+ * serially instead of forking.
+ *
+ * @param count number of chunk tasks the caller intends to submit
+ * @return true when the reservation was granted
+ */
+ public boolean tryReserveTasks(final int count) {
+ if (submittedTaskCount.addAndGet(count) > maxTasks) {
+ submittedTaskCount.addAndGet(-count);
+ return false;
+ }
+ return true;
+ }
+
+ /**
+ * Submits one chunk task. May be called from the orchestrating thread
+ * (root fork) or from inside a running chunk task (nested fork).
+ * Callers must have reserved budget via {@link #tryReserveTasks(int)}.
+ *
+ * @param task transforms a chunk of children into a private aggregator
+ */
+ public void submit(final Callable<RenderAggregator> task) {
+ if (eu.svjatoslav.aukio.e3d.diag.ThreadActivityRecorder.isEnabled()) {
+ final int parity = traceParity;
+ futures.add(executor.submit(() -> {
+ final long t0 = System.nanoTime();
+ try {
+ return task.call();
+ } finally {
+ eu.svjatoslav.aukio.e3d.diag.ThreadActivityRecorder.record(
+ eu.svjatoslav.aukio.e3d.diag.ThreadActivityRecorder.KIND_TRANSFORM + parity,
+ t0, System.nanoTime());
+ }
+ }));
+ return;
+ }
+ futures.add(executor.submit(task));
+ }
+
+ /**
+ * Total chunk tasks submitted to this coordinator, across all nesting
+ * levels. Diagnostics for tests and profiling.
+ *
+ * @return number of submitted chunk tasks
+ */
+ public int getSubmittedTaskCount() {
+ return submittedTaskCount.get();
+ }
+
+ /**
+ * Waits for all submitted chunk tasks, including tasks submitted by
+ * other tasks (nested forks), and merges their aggregators into
+ * {@code target}. Must be called from the single orchestrating render
+ * thread after the root composite's {@code transform()} returns.
+ *
+ * <p>Termination is guaranteed: a task enqueues all its own submissions
+ * before completing, so once every future polled so far has completed
+ * and the queue is empty, no further submissions can arrive.</p>
+ *
+ * @param target the root aggregator to merge results into
+ */
+ public void drainAndMergeInto(final RenderAggregator target) {
+ final boolean trace = eu.svjatoslav.aukio.e3d.diag.ThreadActivityRecorder.isEnabled();
+ final java.util.List<RenderAggregator> parts = new java.util.ArrayList<>();
+ Future<RenderAggregator> future;
+ while ((future = futures.poll()) != null) {
+ try {
+ final long t0 = trace ? System.nanoTime() : 0;
+ parts.add(future.get());
+ if (trace) {
+ eu.svjatoslav.aukio.e3d.diag.ThreadActivityRecorder.record(
+ eu.svjatoslav.aukio.e3d.diag.ThreadActivityRecorder.KIND_AWAIT,
+ t0, System.nanoTime());
+ }
+ } catch (final InterruptedException e) {
+ Thread.currentThread().interrupt();
+ throw new RuntimeException("Interrupted during parallel transform", e);
+ } catch (final ExecutionException e) {
+ throw new RuntimeException("Parallel transform task failed", e.getCause());
+ }
+ }
+ target.mergeAllParallel(parts, executor);
+ // Return chunk aggregators to the pool: reset() keeps their
+ // queue capacity, so next frame's chunks start at steady-state
+ // size instead of re-growing by doubling copies.
+ for (final RenderAggregator part : parts) {
+ part.reset();
+ AGGREGATOR_POOL.offer(part);
+ }
+ }
+}
--- /dev/null
+package eu.svjatoslav.aukio.e3d.renderer.raster;
+
+/**
+ * Stable LSD radix sort over parallel (key, index) arrays, plus the
+ * Z-to-sortable-key mapping used by {@link RenderAggregator}'s fast sort
+ * path. Byte-wise LSD passes make the sort stable, so equal keys keep
+ * their original relative order; the caller resolves remaining ties
+ * explicitly (by shapeId) afterwards.
+ *
+ * <p>Keys are interpreted as unsigned 64-bit values (digit extraction is
+ * unsigned); {@link #zSortKey(double)} returns keys pre-biased so that
+ * unsigned key order equals the comparator's paint order.</p>
+ */
+final class RadixLongSort {
+
+ private RadixLongSort() {
+ }
+
+ /**
+ * Maps a camera-space Z (already depth-bias adjusted) to a 64-bit key
+ * whose unsigned order is DESCENDING in z — i.e. the painter's
+ * back-to-front order. Matches the comparator's contract:
+ *
+ * <ul>
+ * <li>{@code z1 > z2} (double semantics) iff key1 unsigned< key2;</li>
+ * <li>{@code -0.0} is normalized to {@code +0.0} — the comparator
+ * compares with {@code <}/{@code >}, which treats them equal,
+ * so they must share one key;</li>
+ * <li>NaN (never expected: queued shapes passed the near-plane
+ * cull) maps to one canonical key, making all-NaN ties resolve
+ * deterministically by shapeId.</li>
+ * </ul>
+ */
+ static long zSortKey(final double zIn) {
+ double z = zIn;
+ if (z == 0.0d)
+ z = 0.0d; // normalize -0.0 -> +0.0
+ long bits = Double.doubleToRawLongBits(z);
+ // IEEE 754 -> monotone signed long (negatives flip magnitude bits)
+ bits ^= (bits >> 63) & 0x7fffffffffffffffL;
+ // descending order + unsigned-digit friendliness
+ return ~bits ^ Long.MIN_VALUE;
+ }
+
+ /**
+ * Ascending-Z variant for z-buffer mode: the opaque pass paints
+ * front-to-back for early-z rejection (correctness comes from the
+ * depth test, so order is purely a performance heuristic). Ties map
+ * to equal keys exactly like {@link #zSortKey}.
+ */
+ static long zSortKeyAscending(final double zIn) {
+ double z = zIn;
+ if (z == 0.0d)
+ z = 0.0d;
+ long bits = Double.doubleToRawLongBits(z);
+ bits ^= (bits >> 63) & 0x7fffffffffffffffL;
+ return bits ^ Long.MIN_VALUE;
+ }
+
+ /**
+ * Stable LSD radix sort of pairs {@code (keys[i], idx[i])}, ascending
+ * by unsigned key interpretation. Eight 8-bit counting passes; the
+ * even pass count leaves the result back in {@code keys}/{@code idx}
+ * (no final copy). Scratch arrays must be at least n long.
+ */
+ static void sortPairs(final long[] keys, final int[] idx, final int n,
+ final long[] keyTmp, final int[] idxTmp) {
+ long[] srcK = keys;
+ long[] dstK = keyTmp;
+ int[] srcI = idx;
+ int[] dstI = idxTmp;
+ final int[] count = new int[256];
+ for (int shift = 0; shift < 64; shift += 8) {
+ java.util.Arrays.fill(count, 0);
+ for (int i = 0; i < n; i++)
+ count[(int) ((srcK[i] >>> shift) & 0xFF)]++;
+ int sum = 0;
+ for (int d = 0; d < 256; d++) {
+ final int c = count[d];
+ count[d] = sum;
+ sum += c;
+ }
+ for (int i = 0; i < n; i++) {
+ final int d = (int) ((srcK[i] >>> shift) & 0xFF);
+ final int p = count[d]++;
+ dstK[p] = srcK[i];
+ dstI[p] = srcI[i];
+ }
+ final long[] tk = srcK;
+ srcK = dstK;
+ dstK = tk;
+ final int[] ti = srcI;
+ srcI = dstI;
+ dstI = ti;
+ }
+ // 8 passes: after the final swap the sorted pairs are back in the
+ // caller's keys/idx arrays.
+ }
+
+ /**
+ * Parallel variant of {@link #sortPairs}: each pass builds per-chunk
+ * histograms concurrently, then computes scatter offsets digit-major /
+ * chunk-minor (chunk t's elements precede chunk t+1's within a digit),
+ * then scatters per chunk concurrently. That offset order preserves
+ * LSD stability exactly, so the result is IDENTICAL to the serial
+ * sort for any chunk count — the work partitioning is invisible to
+ * the output. Tasks are recorded on the thread-activity timeline like
+ * the rest of the sort machinery.
+ *
+ * @param histScratch scratch for per-chunk histograms and scatter
+ * offsets, length ≥ {@code threads * 512}
+ * @param threads chunk count (1 = fall back to the serial sort)
+ */
+ static void sortPairsParallel(final long[] keys, final int[] idx, final int n,
+ final long[] keyTmp, final int[] idxTmp,
+ final int[] histScratch,
+ final java.util.concurrent.ExecutorService executor,
+ final int threads) {
+ if (threads <= 1 || executor == null) {
+ sortPairs(keys, idx, n, keyTmp, idxTmp);
+ return;
+ }
+ long[] srcK = keys;
+ long[] dstK = keyTmp;
+ int[] srcI = idx;
+ int[] dstI = idxTmp;
+ final int chunk = (n + threads - 1) / threads;
+ for (int shift = 0; shift < 64; shift += 8) {
+ final int s = shift;
+ final long[] sk = srcK;
+ final long[] dk = dstK;
+ final int[] si = srcI;
+ final int[] di = dstI;
+
+ // Phase A: per-chunk histograms (concurrent)
+ runChunks(executor, n, chunk, (t, from, to) -> {
+ java.util.Arrays.fill(histScratch, t * 256, t * 256 + 256, 0);
+ for (int i = from; i < to; i++)
+ histScratch[t * 256 + (int) ((sk[i] >>> s) & 0xFF)]++;
+ });
+
+ // Serial combine: digit-major, chunk-minor offsets — this is
+ // what keeps the parallel sort stable and bit-identical to
+ // the serial one.
+ int pos = 0;
+ final int offsetsBase = threads * 256;
+ for (int d = 0; d < 256; d++)
+ for (int t = 0; t < threads; t++) {
+ final int c = histScratch[t * 256 + d];
+ histScratch[offsetsBase + t * 256 + d] = pos;
+ pos += c;
+ }
+
+ // Phase B: per-chunk scatter (concurrent; each chunk owns its
+ // private offset row)
+ runChunks(executor, n, chunk, (t, from, to) -> {
+ final int base = offsetsBase + t * 256;
+ for (int i = from; i < to; i++) {
+ final int d = (int) ((sk[i] >>> s) & 0xFF);
+ final int p = histScratch[base + d]++;
+ dk[p] = sk[i];
+ di[p] = si[i];
+ }
+ });
+
+ final long[] tk = srcK;
+ srcK = dstK;
+ dstK = tk;
+ final int[] ti = srcI;
+ srcI = dstI;
+ dstI = ti;
+ }
+ }
+
+ /** One unit of chunk work: chunk index t and its [from, to) range. */
+ interface ChunkWork {
+ void run(int t, int from, int to);
+ }
+
+ /**
+ * Runs {@code work} for every non-empty chunk concurrently on
+ * {@code executor} and awaits completion; each task is recorded as
+ * KIND_SORT on the thread-activity timeline. Package-visible: the
+ * aggregator reuses it for the parallel key-build and permute.
+ */
+ static void runChunks(final java.util.concurrent.ExecutorService executor,
+ final int n, final int chunk,
+ final ChunkWork work) {
+ final java.util.List<java.util.concurrent.Future<?>> futures =
+ new java.util.ArrayList<>();
+ for (int t = 0, from = 0; from < n; t++, from += chunk) {
+ final int ti = t;
+ final int f = from;
+ final int to = Math.min(n, from + chunk);
+ futures.add(executor.submit(() -> {
+ final boolean trace =
+ eu.svjatoslav.aukio.e3d.diag.ThreadActivityRecorder.isEnabled();
+ final long t0 = trace ? System.nanoTime() : 0;
+ try {
+ work.run(ti, f, to);
+ } finally {
+ if (trace)
+ eu.svjatoslav.aukio.e3d.diag.ThreadActivityRecorder.record(
+ eu.svjatoslav.aukio.e3d.diag.ThreadActivityRecorder.KIND_SORT,
+ t0, System.nanoTime());
+ }
+ }));
+ }
+ try {
+ for (final java.util.concurrent.Future<?> future : futures)
+ future.get();
+ } catch (final InterruptedException e) {
+ Thread.currentThread().interrupt();
+ throw new RuntimeException("Interrupted during parallel radix sort", e);
+ } catch (final java.util.concurrent.ExecutionException e) {
+ throw new RuntimeException("Task failed during parallel radix sort",
+ e.getCause());
+ }
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster;
+
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.AbstractCoordinateShape;
+
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.List;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Future;
+
+/**
+ * Collects transformed shapes during a render frame and paints them in depth-sorted order.
+ *
+ * <p>Shapes are sorted from back to front (highest Z-depth first). Under the
+ * (unconditional) z-buffer, occlusion correctness comes from the per-pixel
+ * depth test; the queue order is a performance and coherence heuristic:
+ * pass 1 paints opaque shapes front-to-back (queue reversed) so the depth
+ * test rejects hidden fragments before the texture fetch, pass 2 paints
+ * alpha shapes back-to-front without depth writes so translucent overlap
+ * stays painter-coherent.</p>
+ *
+ * <p>When two shapes have the same Z-depth, their unique {@link AbstractCoordinateShape#shapeId}
+ * is used as a tiebreaker to guarantee deterministic rendering order.</p>
+ *
+ * <p>This class is used internally by {@link ShapeCollection} during the render pipeline.
+ * You typically do not need to interact with it directly.</p>
+ *
+ * @see ShapeCollection#paintShapes(RenderingContext)
+ * @see AbstractCoordinateShape#getZ(int)
+ */
+public class RenderAggregator {
+
+ /**
+ * Creates a new render aggregator.
+ */
+ public RenderAggregator() {
+ this(0);
+ }
+
+ /**
+ * Creates an aggregator bound to a projection buffer slot. Sorting and
+ * tile binning read the shapes' screen state for this slot, so the
+ * triple-buffered pipeline can fill one slot's aggregator while the
+ * other slots' aggregators are still being painted.
+ *
+ * @param slot the buffer slot (0..2) this aggregator serves
+ */
+ public RenderAggregator(final int slot) {
+ this.slot = slot;
+ }
+
+ /** Buffer slot whose screen state this aggregator sorts and bins by. */
+ private final int slot;
+
+ private final ArrayList<AbstractCoordinateShape> shapes = new ArrayList<>();
+ private final ShapesZIndexComparator comparator = new ShapesZIndexComparator();
+ private boolean sorted = false;
+
+ /**
+ * The sorted queue as a flat array, produced by {@link #sort()}.
+ * Paint and binning iterate this instead of the list: sorting works
+ * on the array in place, so the queue is copied exactly once.
+ * The backing array is REUSED across frames (grow-only); only the
+ * first {@link #sortedCount} entries are valid.
+ */
+ private AbstractCoordinateShape[] sortedArray;
+ /** Valid entries of {@link #sortedArray} (it is oversized by reuse). */
+ private int sortedCount;
+
+ /**
+ * Reusable flat queue storage (grow-only). {@link #sort()} fills it
+ * either from the shape list or from {@link #mergeAllParallel}.
+ */
+ private AbstractCoordinateShape[] queueArray;
+ /** Valid entries of {@link #queueArray} after a merge. */
+ private int pendingMergeCount;
+
+ /** Reusable permutation scratch (grow-only), see tryRadixSort. */
+ private AbstractCoordinateShape[] sortScratch;
+
+ /** Radix-sort scratch (grow-only): keys, indices, and their swap
+ * buffers, plus the tie-run pack array. See tryRadixSort. */
+ private long[] radixKeys;
+ private long[] radixKeysTmp;
+ private long[] tiePack;
+ private int[] radixIdx;
+ private int[] radixIdxTmp;
+ /** Per-chunk histogram/offset scratch for the parallel radix passes. */
+ private int[] radixHist;
+
+ private static long[] ensureCapacity(final long[] array, final int capacity) {
+ return (array != null && array.length >= capacity)
+ ? array : new long[capacity];
+ }
+
+ private static int[] ensureCapacity(final int[] array, final int capacity) {
+ return (array != null && array.length >= capacity)
+ ? array : new int[capacity];
+ }
+
+ /** Grow-only capacity helper: returns {@code array} or a bigger one. */
+ private static AbstractCoordinateShape[] ensureCapacity(
+ final AbstractCoordinateShape[] array, final int capacity) {
+ return array != null && array.length >= capacity
+ ? array : new AbstractCoordinateShape[capacity];
+ }
+
+ /**
+ * Sorts all queued shapes by Z-depth (back to front) and paints them.
+ *
+ * @param renderBuffer the rendering context to paint shapes into
+ */
+ public void paint(final RenderingContext renderBuffer) {
+ ensureSorted();
+ paintSorted(renderBuffer);
+ }
+
+ /**
+ * Above this many queued shapes, {@link #sort()} uses the radix path
+ * (parallel when an executor is available) instead of a comparator sort.
+ */
+ private static final int PARALLEL_SORT_THRESHOLD = 8192;
+
+ /**
+ * Sorts all queued shapes by Z-depth (back to front).
+ * Must be called after all shapes are queued and before paintSorted.
+ * Uses a parallel sort for large queues.
+ */
+ public void sort() {
+ sort(null);
+ }
+
+ /**
+ * Sorts the queue by (Z, shapeId). Large queues go through the radix
+ * path (see {@link #tryRadixSort}), which is parallel when an executor
+ * is given; small queues use a plain comparator sort. Deterministic:
+ * (Z, shapeId) is a total order, so every path yields the same result.
+ *
+ * @param executor executor for parallel sorting, or null for serial
+ */
+ public void sort(final ExecutorService executor) {
+ if (!sorted) {
+ comparator.sortSlot = slot;
+ if (pendingMergeCount > 0) {
+ // Merge already produced a flat array: sort it in place,
+ // no list copy at all
+ sortedArray = queueArray;
+ sortedCount = pendingMergeCount;
+ pendingMergeCount = 0;
+ } else {
+ // toArray(target) reuses the target when it fits:
+ // zero-allocation queue copy at steady state
+ sortedCount = shapes.size();
+ sortedArray = shapes.toArray(
+ ensureCapacity(queueArray, sortedCount));
+ queueArray = sortedArray;
+ }
+ if (sortedCount >= PARALLEL_SORT_THRESHOLD) {
+ tryRadixSort(sortedArray, sortedCount, executor);
+ } else {
+ Arrays.sort(sortedArray, 0, sortedCount, comparator);
+ }
+ sorted = true;
+ }
+ }
+
+ /**
+ * Fast sort: maps Z-depth to unsigned-ordered long keys, stable-sorts
+ * (key, queueIndex) pairs with an LSD radix sort, then fixes equal-key
+ * runs to ascending shapeId — reproducing the comparator's total order
+ * (Z descending, shapeId ascending) exactly, without a single
+ * comparator call. Sequential memory throughout: key build and the
+ * final permute stream the queue array, the radix passes stream
+ * long/int arrays. With an executor the key build, radix passes and
+ * permute run chunked in parallel (bit-identical to serial: stability
+ * makes the partitioning invisible).
+ */
+ private void tryRadixSort(final AbstractCoordinateShape[] array,
+ final int length,
+ final ExecutorService executor) {
+ radixKeys = ensureCapacity(radixKeys, length);
+ radixKeysTmp = ensureCapacity(radixKeysTmp, length);
+ radixIdx = ensureCapacity(radixIdx, length);
+ radixIdxTmp = ensureCapacity(radixIdxTmp, length);
+
+ // Sweet spot measured on a 24-core desktop (450k pairs, SortSweep
+ // harness): ~16-24 chunks; below ~4 chunks bandwidth stays
+ // underutilized, and every chunk costs 2 task submissions per pass.
+ final int threads = executor == null ? 1
+ : Math.max(1, Math.min(
+ Runtime.getRuntime().availableProcessors(),
+ length / 16384));
+
+ final long[] keys = radixKeys;
+ final int[] idx = radixIdx;
+ if (threads > 1) {
+ RadixLongSort.runChunks(executor, length, (length + threads - 1) / threads,
+ (t, from, to) -> {
+ for (int i = from; i < to; i++) {
+ keys[i] = RadixLongSort.zSortKey(array[i].getZ(slot));
+ idx[i] = i;
+ }
+ });
+ } else {
+ for (int i = 0; i < length; i++) {
+ radixKeys[i] = RadixLongSort.zSortKey(array[i].getZ(slot));
+ radixIdx[i] = i;
+ }
+ }
+
+ if (threads > 1) {
+ radixHist = ensureCapacity(radixHist, threads * 512);
+ RadixLongSort.sortPairsParallel(radixKeys, radixIdx, length,
+ radixKeysTmp, radixIdxTmp, radixHist, executor, threads);
+ } else {
+ RadixLongSort.sortPairs(radixKeys, radixIdx, length,
+ radixKeysTmp, radixIdxTmp);
+ }
+
+ // Equal-key runs must resolve by ascending shapeId (the
+ // comparator's tie-break; queue order is NOT construction order).
+ // Runs are almost always singletons — the pack array only
+ // materializes for actual ties.
+ int runStart = 0;
+ while (runStart < length) {
+ int runEnd = runStart + 1;
+ final long key = radixKeys[runStart];
+ while (runEnd < length && radixKeys[runEnd] == key)
+ runEnd++;
+ if (runEnd - runStart > 1) {
+ final int runLength = runEnd - runStart;
+ tiePack = ensureCapacity(tiePack, runLength);
+ for (int i = 0; i < runLength; i++)
+ tiePack[i] =
+ ((array[radixIdx[runStart + i]].shapeId
+ & 0xffffffffL) << 32)
+ | (radixIdx[runStart + i] & 0xffffffffL);
+ java.util.Arrays.sort(tiePack, 0, runLength);
+ for (int i = 0; i < runLength; i++)
+ radixIdx[runStart + i] = (int) tiePack[i];
+ }
+ runStart = runEnd;
+ }
+ sortScratch = ensureCapacity(sortScratch, length);
+ final AbstractCoordinateShape[] scratch = sortScratch;
+ if (threads > 1) {
+ RadixLongSort.runChunks(executor, length, (length + threads - 1) / threads,
+ (t, from, to) -> {
+ for (int i = from; i < to; i++)
+ scratch[i] = array[radixIdx[i]];
+ });
+ } else {
+ for (int i = 0; i < length; i++)
+ sortScratch[i] = array[radixIdx[i]];
+ }
+ System.arraycopy(sortScratch, 0, array, 0, length);
+ }
+
+ private static void awaitAll(final java.util.List<Future<?>> futures, final String what) {
+ try {
+ for (final Future<?> future : futures)
+ future.get();
+ } catch (final InterruptedException e) {
+ Thread.currentThread().interrupt();
+ throw new RuntimeException("Interrupted during " + what, e);
+ } catch (final ExecutionException e) {
+ throw new RuntimeException("Task failed during " + what, e.getCause());
+ }
+ }
+
+ private void ensureSorted() {
+ sort();
+ }
+
+ /**
+ * Paints all shapes that have already been sorted.
+ * This method can be called multiple times with different segment contexts
+ * for multi-threaded rendering.
+ *
+ * <p>If {@link #binForTiles} was called and the given context's bounds
+ * exactly match one tile, only that tile's bin is iterated — shapes
+ * that cannot touch the tile are skipped entirely. Otherwise the full
+ * sorted queue is iterated (every shape clips itself to the context
+ * bounds, so the painted result is identical).</p>
+ *
+ * @param renderBuffer the rendering context to paint shapes into
+ */
+ public void paintSorted(final RenderingContext renderBuffer) {
+ // Two passes. Opaque class first, front-to-back (the queue is
+ // back-to-front, so iterate it in reverse) with depth test +
+ // write — early-z rejects hidden surfaces before texturing.
+ // Alpha class second, in queue order (back-to-front):
+ // depth-tested against the opaque result but never
+ // depth-written, so cutout foliage keeps painter-coherent
+ // overlap among itself.
+ renderBuffer.depthPass = 1;
+ paintRange(renderBuffer, true);
+ renderBuffer.depthPass = 2;
+ paintRange(renderBuffer, false);
+ renderBuffer.depthPass = 0;
+ }
+
+ /** Iterates the matching bin (or the full sorted queue), optionally
+ * in reverse. */
+ private void paintRange(final RenderingContext renderBuffer,
+ final boolean reverse) {
+ final int bin = matchingBinIndex(renderBuffer);
+ if (bin >= 0) {
+ final int start = binStart[bin];
+ final int end = start + binCount[bin];
+ if (reverse) {
+ for (int i = end - 1; i >= start; i--)
+ binEntries[i].paint(renderBuffer);
+ } else {
+ for (int i = start; i < end; i++)
+ binEntries[i].paint(renderBuffer);
+ }
+ return;
+ }
+ if (sortedArray != null) {
+ if (reverse) {
+ for (int i = sortedCount - 1; i >= 0; i--)
+ sortedArray[i].paint(renderBuffer);
+ } else {
+ for (int i = 0; i < sortedCount; i++)
+ sortedArray[i].paint(renderBuffer);
+ }
+ } else {
+ for (int i = 0; i < shapes.size(); i++)
+ shapes.get(i).paint(renderBuffer);
+ }
+ }
+
+ /**
+ * Tile bins in CSR (compressed-sparse-row) form: one flat,
+ * grow-only entry array plus per-tile start/count. Built fresh
+ * each frame into REUSED arrays — the previous design allocated a
+ * fresh ArrayList per tile per chunk per frame (thousands of list
+ * objects plus their backing arrays at FO4 queue sizes).
+ */
+ private AbstractCoordinateShape[] binEntries;
+ private int[] binStart;
+ private int[] binCount;
+ /** Per-(chunk × tile) scratch: counts in phase 1, write offsets in phase 3. */
+ private int[] binScratch;
+ private int binTilesX;
+ private int binTilesY;
+ private int binOriginX;
+ private int binTileW;
+ private int binTileH;
+ private int binWidth;
+ private int binHeight;
+ private boolean binsActive;
+
+ /**
+ * Returns the bin matching the given context's X/Y bounds, or -1
+ * when the context does not correspond to exactly one binned tile.
+ *
+ * @param renderBuffer the rendering context to match
+ * @return the bin index, or -1 for full-queue iteration
+ */
+ private int matchingBinIndex(final RenderingContext renderBuffer) {
+ if (!binsActive)
+ return -1;
+ final int tx = matchAxis(renderBuffer.renderMinX, renderBuffer.renderMaxX,
+ binOriginX, binTileW, binTilesX, binWidth);
+ if (tx < 0)
+ return -1;
+ final int ty = matchAxis(renderBuffer.renderMinY, renderBuffer.renderMaxY,
+ 0, binTileH, binTilesY, binHeight);
+ if (ty < 0)
+ return -1;
+ return ty * binTilesX + tx;
+ }
+
+ /**
+ * Matches one axis of a context against the tile grid.
+ *
+ * @param min context minimum coordinate on this axis
+ * @param max context maximum coordinate (exclusive) on this axis
+ * @param origin grid origin on this axis
+ * @param tileSize tile size on this axis
+ * @param count tile count on this axis
+ * @param total total grid extent on this axis (last tile reaches it)
+ * @return the tile index on this axis, or -1 when no exact match
+ */
+ private static int matchAxis(final int min, final int max, final int origin,
+ final int tileSize, final int count, final int total) {
+ final int rel = min - origin;
+ if (rel < 0 || rel % tileSize != 0)
+ return -1;
+ final int index = rel / tileSize;
+ if (index >= count)
+ return -1;
+ final int expectedMax = (index == count - 1)
+ ? origin + total : origin + (index + 1) * tileSize;
+ return max == expectedMax ? index : -1;
+ }
+
+ /**
+ * Below this many queued shapes the bin build runs serially; the
+ * fork/join overhead would dominate.
+ */
+ private static final int PARALLEL_BIN_MIN_SHAPES = 8192;
+
+ /**
+ * Bins the sorted queue per rectangular paint tile by screen-space
+ * overlap. Must be called after {@link #sort()} and before tile
+ * painting. Built once per frame (per eye, in stereo) on the render
+ * thread; the bins are read-only during parallel painting.
+ *
+ * <p>Each bin preserves the global (Z, shapeId) sort order, so painting
+ * a bin produces exactly the same pixels as painting the full queue
+ * into that tile. Shapes are assigned with their
+ * {@link AbstractCoordinateShape#onScreenMinY} / {@code onScreenMaxY} /
+ * {@code onScreenMinX} / {@code onScreenMaxX} bounds, which include a
+ * per-shape margin for paint output extending past the vertices
+ * (thick lines, billboards, text glyphs).</p>
+ *
+ * <p>Mouse hit detection is unaffected: a hit requires the cursor to be
+ * inside the shape, so the shape always overlaps the tile containing
+ * the cursor.</p>
+ *
+ * <p>When an executor is given and the queue is large, the sorted list
+ * is scanned in per-core chunks concurrently and the per-chunk bins are
+ * concatenated in chunk order, preserving the global sort order.</p>
+ *
+ * @param tilesX tile columns across the viewport
+ * @param tilesY tile rows down the viewport
+ * @param originX X origin of the tiled viewport (eye offset in stereo)
+ * @param width tiled viewport width in pixels
+ * @param height full render height in pixels
+ * @param executor executor for parallel binning, or null for serial
+ */
+ public void binForTiles(final int tilesX, final int tilesY,
+ final int originX, final int width, final int height,
+ final ExecutorService executor) {
+ ensureSorted();
+
+ binsActive = false;
+ final int tileW = width / tilesX;
+ final int tileH = height / tilesY;
+ if (tilesX < 1 || tilesY < 1 || tileW <= 0 || tileH <= 0
+ || sortedCount == 0)
+ return;
+
+ buildBins(tilesX, tilesY, originX, tileW, tileH,
+ tilesX * tilesY, executor);
+
+ binsActive = true;
+ binTilesX = tilesX;
+ binTilesY = tilesY;
+ binOriginX = originX;
+ binTileW = tileW;
+ binTileH = tileH;
+ binWidth = width;
+ binHeight = height;
+ }
+
+ /**
+ * Floor of {@code value} as an int. The {@code (int)} cast truncates
+ * toward zero; decrement when the truncated value overshoots to get
+ * floor semantics for negatives.
+ */
+ private static int floorInt(final double value) {
+ final int result = (int) value;
+ return result > value ? result - 1 : result;
+ }
+
+ /**
+ * Builds the CSR bins in three phases over grow-only reused arrays:
+ * per-chunk counting (parallel), a tiny serial prefix pass, then
+ * per-chunk fill (parallel). Per-bin order is preserved exactly as
+ * with the old per-chunk-ArrayList concatenation: chunks cut the
+ * sorted queue contiguously and each bin's slices are laid down in
+ * chunk order.
+ */
+ private void buildBins(final int tilesX, final int tilesY,
+ final int originX, final int tileW, final int tileH,
+ final int tileCount,
+ final ExecutorService executor) {
+ final AbstractCoordinateShape[] queue = sortedArray;
+ final int size = sortedCount;
+ final int targetTasks = Runtime.getRuntime().availableProcessors() * 4;
+ final int chunkSize = Math.max(1024, (size + targetTasks - 1) / targetTasks);
+ final int chunkCount = (size + chunkSize - 1) / chunkSize;
+ final double invTileW = 1.0 / tileW;
+ final double invTileH = 1.0 / tileH;
+
+ if (binStart == null || binStart.length < tileCount) {
+ binStart = new int[tileCount];
+ binCount = new int[tileCount];
+ }
+ if (binScratch == null || binScratch.length < chunkCount * tileCount) {
+ binScratch = new int[chunkCount * tileCount];
+ } else {
+ java.util.Arrays.fill(binScratch, 0, chunkCount * tileCount, 0);
+ }
+
+ final boolean parallel = executor != null
+ && size >= PARALLEL_BIN_MIN_SHAPES && chunkCount > 1;
+
+ // Phase 1: count shapes per (chunk, tile)
+ binPhase(queue, tilesX, tilesY, originX, invTileW, invTileH,
+ chunkCount, chunkSize, tileCount, true, parallel, executor);
+
+ // Phase 2 (serial, tiny): per-tile prefix over chunks -> each
+ // chunk's write offset within the tile; per-tile totals ->
+ // binStart/binCount; overall capacity for the flat entries array
+ int total = 0;
+ for (int t = 0; t < tileCount; t++) {
+ int tileTotal = 0;
+ for (int c = 0; c < chunkCount; c++) {
+ final int idx = c * tileCount + t;
+ final int n = binScratch[idx];
+ binScratch[idx] = tileTotal;
+ tileTotal += n;
+ }
+ binStart[t] = total;
+ binCount[t] = tileTotal;
+ total += tileTotal;
+ }
+ binEntries = ensureCapacity(binEntries, total);
+
+ // Phase 3: fill; each chunk bumps only its own scratch row
+ binPhase(queue, tilesX, tilesY, originX, invTileW, invTileH,
+ chunkCount, chunkSize, tileCount, false, parallel, executor);
+ }
+
+ /** Runs one bin phase over all chunks, inline or on the executor. */
+ private void binPhase(final AbstractCoordinateShape[] queue,
+ final int tilesX, final int tilesY,
+ final int originX,
+ final double invTileW, final double invTileH,
+ final int chunkCount, final int chunkSize,
+ final int tileCount,
+ final boolean countMode,
+ final boolean parallel,
+ final ExecutorService executor) {
+ final int size = sortedCount;
+ final boolean trace = eu.svjatoslav.aukio.e3d.diag.ThreadActivityRecorder.isEnabled();
+ final int traceKind = eu.svjatoslav.aukio.e3d.diag.ThreadActivityRecorder.KIND_BIN
+ + eu.svjatoslav.aukio.e3d.diag.ThreadActivityRecorder.frameParity();
+ final java.util.List<Future<?>> futures =
+ parallel ? new java.util.ArrayList<>(chunkCount) : null;
+ for (int c = 0; c < chunkCount; c++) {
+ final int chunk = c;
+ final int from = c * chunkSize;
+ final int to = Math.min(size, from + chunkSize);
+ final Runnable body = () -> {
+ final long t0 = trace ? System.nanoTime() : 0;
+ try {
+ binRangeCsr(queue, tilesX, tilesY, originX,
+ invTileW, invTileH, from, to,
+ chunk * tileCount, countMode);
+ } finally {
+ if (trace)
+ eu.svjatoslav.aukio.e3d.diag.ThreadActivityRecorder.record(
+ traceKind, t0, System.nanoTime());
+ }
+ };
+ if (parallel)
+ futures.add(executor.submit(body));
+ else
+ body.run();
+ }
+ if (parallel)
+ awaitAll(futures, "parallel binning");
+ }
+
+ /**
+ * Assigns shapes[from..to) to tile bins by X/Y overlap. In count
+ * mode, increments binScratch per (chunk, tile); in fill mode,
+ * writes entries at binStart[tile] + running chunk offset. Both
+ * modes iterate in queue order, preserving (Z, shapeId) within bins.
+ */
+ private void binRangeCsr(final AbstractCoordinateShape[] queue,
+ final int tilesX, final int tilesY,
+ final int originX,
+ final double invTileW, final double invTileH,
+ final int from, final int to,
+ final int scratchBase,
+ final boolean countMode) {
+ for (int i = from; i < to; i++) {
+ final AbstractCoordinateShape shape = queue[i];
+
+ int firstY = floorInt(shape.onScreenMinY(slot) * invTileH);
+ int lastY = floorInt(shape.onScreenMaxY(slot) * invTileH);
+ if (lastY < 0 || firstY >= tilesY)
+ continue;
+ if (firstY < 0)
+ firstY = 0;
+ if (lastY >= tilesY)
+ lastY = tilesY - 1;
+
+ int firstX = floorInt((shape.onScreenMinX(slot) - originX) * invTileW);
+ int lastX = floorInt((shape.onScreenMaxX(slot) - originX) * invTileW);
+ if (lastX < 0 || firstX >= tilesX)
+ continue;
+ if (firstX < 0)
+ firstX = 0;
+ if (lastX >= tilesX)
+ lastX = tilesX - 1;
+
+ for (int ty = firstY; ty <= lastY; ty++) {
+ final int rowBase = ty * tilesX;
+ for (int tx = firstX; tx <= lastX; tx++) {
+ final int tile = rowBase + tx;
+ if (countMode) {
+ binScratch[scratchBase + tile]++;
+ } else {
+ binEntries[binStart[tile]
+ + binScratch[scratchBase + tile]++] = shape;
+ }
+ }
+ }
+ }
+ }
+
+ /**
+ * Returns the number of shapes currently queued.
+ *
+ * @return the shape count
+ */
+ public int size() {
+ if (sortedArray != null)
+ return sortedCount;
+ if (pendingMergeCount > 0)
+ return pendingMergeCount;
+ return shapes.size();
+ }
+
+ /**
+ * Queues a shape for rendering. Called during the transform phase.
+ *
+ * @param shape the shape to queue
+ */
+ public void queueShapeForRendering(final AbstractCoordinateShape shape) {
+ shapes.add(shape);
+ binsActive = false;
+ }
+
+ /**
+ * Merges all shapes queued in another aggregator into this one.
+ * Used to combine the per-task queues produced by the parallel
+ * transform phase. Merge order does not affect the final render order:
+ * {@link #sort()} is deterministic on (Z, shapeId).
+ *
+ * @param other the aggregator whose queued shapes are moved into this one
+ */
+ public void mergeFrom(final RenderAggregator other) {
+ shapes.addAll(other.shapes);
+ sorted = false;
+ binsActive = false;
+ }
+
+ /**
+ * Merges many chunk aggregators into this one, producing a flat
+ * array that {@link #sort()} consumes directly. The per-chunk lists
+ * are copied into the merged array by parallel copy tasks on the
+ * given executor — the old per-chunk {@code addAll} chain
+ * (reallocating the target list serially) is gone. Merge order is
+ * irrelevant: the following sort re-establishes deterministic
+ * (Z, shapeId) order.
+ *
+ * @param parts chunk aggregators to merge
+ * @param executor executor for the parallel copy, or null for serial
+ */
+ public void mergeAllParallel(final List<RenderAggregator> parts,
+ final ExecutorService executor) {
+ final int ownSize = shapes.size();
+ int total = ownSize;
+ for (final RenderAggregator part : parts)
+ total += part.shapes.size();
+
+ // Reused flat storage (grow-only); lists are copied out with
+ // plain indexed loops — no per-part toArray copies
+ queueArray = ensureCapacity(queueArray, total);
+ final AbstractCoordinateShape[] merged = queueArray;
+ final int partCount = parts.size();
+ final int[] offsets = new int[partCount + 1];
+ offsets[0] = ownSize;
+ for (int i = 0; i < partCount; i++)
+ offsets[i + 1] = offsets[i] + parts.get(i).shapes.size();
+
+ for (int j = 0; j < ownSize; j++)
+ merged[j] = shapes.get(j);
+ shapes.clear();
+
+ if (executor == null || partCount < 2 || total < 8192) {
+ for (int i = 0; i < partCount; i++) {
+ final ArrayList<AbstractCoordinateShape> partShapes = parts.get(i).shapes;
+ for (int j = 0; j < partShapes.size(); j++)
+ merged[offsets[i] + j] = partShapes.get(j);
+ }
+ } else {
+ final int copyTasks = Math.min(partCount,
+ Runtime.getRuntime().availableProcessors());
+ final int perTask = (partCount + copyTasks - 1) / copyTasks;
+ final List<Future<?>> futures = new ArrayList<>(copyTasks);
+ for (int t = 0; t < copyTasks; t++) {
+ final int from = t * perTask;
+ final int to = Math.min(partCount, from + perTask);
+ if (from >= to)
+ break;
+ futures.add(executor.submit(() -> {
+ for (int i = from; i < to; i++) {
+ final ArrayList<AbstractCoordinateShape> partShapes =
+ parts.get(i).shapes;
+ final int partSize = partShapes.size();
+ for (int j = 0; j < partSize; j++)
+ merged[offsets[i] + j] = partShapes.get(j);
+ }
+ }));
+ }
+ try {
+ for (final Future<?> future : futures)
+ future.get();
+ } catch (final InterruptedException e) {
+ Thread.currentThread().interrupt();
+ throw new RuntimeException("Interrupted during parallel merge", e);
+ } catch (final ExecutionException e) {
+ throw new RuntimeException("Parallel merge task failed", e.getCause());
+ }
+ }
+
+ pendingMergeCount = total;
+ sorted = false;
+ binsActive = false;
+ }
+
+ /**
+ * Returns the live list of queued shapes, in current queue order.
+ * Package-private: exposed for pipeline verification tests.
+ *
+ * @return the queued shapes
+ */
+ List<AbstractCoordinateShape> getQueuedShapes() {
+ if (sortedArray != null)
+ return java.util.Collections.unmodifiableList(
+ Arrays.asList(sortedArray).subList(0, sortedCount));
+ if (pendingMergeCount > 0)
+ return java.util.Collections.unmodifiableList(
+ Arrays.asList(queueArray).subList(0, pendingMergeCount));
+ return shapes;
+ }
+
+ /**
+ * Returns the number of shapes in each segment bin, or null when no
+ * binning is active. Package-private: exposed for pipeline
+ * verification tests.
+ *
+ * @return per-segment bin sizes, or null
+ */
+ int[] getBinSizes() {
+ if (!binsActive)
+ return null;
+ return Arrays.copyOf(binCount, binTilesX * binTilesY);
+ }
+
+ /**
+ * Clears all queued shapes, preparing for a new render frame. The
+ * reusable backing arrays (queue, sort scratch, bin storage) are
+ * kept, so steady-state frames do not reallocate them.
+ */
+ public void reset() {
+ shapes.clear();
+ sortedArray = null;
+ sortedCount = 0;
+ pendingMergeCount = 0;
+ sorted = false;
+ binsActive = false;
+ }
+
+ /**
+ * Comparator that sorts shapes by Z-depth in descending order (farthest first)
+ * for the render queue. Uses shape ID as a tiebreaker.
+ */
+ static class ShapesZIndexComparator implements Comparator<AbstractCoordinateShape>, Serializable {
+
+ /** Buffer slot the in-progress sort reads Z-depths from. */
+ int sortSlot;
+
+ @Override
+ public int compare(final AbstractCoordinateShape o1, final AbstractCoordinateShape o2) {
+ final double z1 = o1.getZ(sortSlot);
+ final double z2 = o2.getZ(sortSlot);
+ if (z1 < z2)
+ return 1;
+ else if (z1 > z2)
+ return -1;
+
+ return Integer.compare(o1.shapeId, o2.shapeId);
+ }
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster;
+import eu.svjatoslav.aukio.e3d.diag.DebugLogBuffer;
+import eu.svjatoslav.aukio.e3d.gui.DeveloperTools;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point2D;
+import eu.svjatoslav.aukio.e3d.gui.humaninput.KeyboardFocusStack;
+import eu.svjatoslav.aukio.e3d.gui.humaninput.MouseEvent;
+import eu.svjatoslav.aukio.e3d.gui.humaninput.MouseInteractionController;
+import eu.svjatoslav.aukio.e3d.renderer.raster.lighting.LightingManager;
+
+import java.awt.*;
+import java.awt.image.BufferedImage;
+import java.awt.image.DataBufferInt;
+import java.awt.image.WritableRaster;
+import java.util.concurrent.ExecutorService;
+import eu.svjatoslav.aukio.e3d.renderer.raster.ParallelTransformCoordinator;
+import java.util.function.Consumer;
+
+/**
+ * Contains all state needed to render a single frame: the pixel buffer, graphics context,
+ * screen dimensions, and mouse event tracking.
+ *
+ * <p>A new {@code RenderingContext} is created whenever the view panel is resized.
+ * During rendering, shapes use this context to:</p>
+ * <ul>
+ * <li>Access the raw pixel array ({@link #pixels}) for direct pixel manipulation</li>
+ * <li>Access the {@link Graphics2D} context ({@link #graphics}) for Java2D drawing</li>
+ * <li>Read screen dimensions ({@link #width}, {@link #height}) and the
+ * {@link #centerCoordinate} for coordinate projection</li>
+ * <li>Use the {@link #projectionScale} factor for perspective projection</li>
+ * </ul>
+ *
+ * <p>The context also manages mouse interaction detection: as shapes are painted
+ * back-to-front, each shape can report itself as the object under the mouse cursor.
+ * After painting completes, the topmost shape receives the mouse event.</p>
+ *
+ * @see eu.svjatoslav.aukio.e3d.gui.ViewPanel the panel that creates and manages this context
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.shapes.AbstractCoordinateShape#paint(RenderingContext)
+ */
+public class RenderingContext {
+
+ /**
+ * The {@link BufferedImage} pixel format used for the rendering buffer.
+ * TYPE_INT_RGB provides optimal performance for Java2D blitting.
+ */
+ public static final int bufferedImageType = BufferedImage.TYPE_INT_RGB;
+
+ /**
+ * Number of horizontal segments (bands) for parallel rendering.
+ * Bands are finer than the paint thread count: paint threads steal
+ * bands off a shared ticket until all bands are done, so a thread
+ * that finishes a cheap band immediately picks up more work.
+ * Derived from the render thread count via
+ * {@link eu.svjatoslav.aukio.e3d.gui.ViewPanel#setNumRenderThreads(int)}.
+ *
+ * <p>Equals {@code tilesX * tilesY * viewportCount}: the tile grid
+ * covers one viewport, and in stereo mode a second grid covers the
+ * other eye (segment indices for the right eye start at
+ * {@code tilesX * tilesY}).</p>
+ */
+ public final int numRenderSegments;
+
+ /** Tile columns per viewport (1 = horizontal bands only). */
+ public final int tilesX;
+
+ /** Tile rows per viewport. */
+ public final int tilesY;
+
+ /** Number of side-by-side viewports (2 in stereo mode, else 1). */
+ public final int viewportCount;
+
+ /**
+ * Java2D graphics context for drawing text, anti-aliased shapes, and other
+ * high-level graphics operations onto the render buffer.
+ */
+ public final Graphics2D graphics;
+
+ /**
+ * Segment-specific Graphics2D contexts, each pre-clipped to a horizontal band.
+ * Used for thread-safe text and shape rendering without synchronization.
+ * Only initialized in the main RenderingContext; null in segment views.
+ */
+ private Graphics2D[] segmentGraphics;
+
+ /**
+ * Pixels of the rendering area.
+ * Each pixel is a single int in RGB format: {@code (r << 16) | (g << 8) | b}.
+ */
+ public final int[] pixels;
+
+ /**
+ * Per-pixel depth (biased 1/z, larger = nearer), always allocated —
+ * the painter path was deleted 2026-09-17 and the z-buffer is the
+ * only visibility mechanism. Shared with segment/pass copies like
+ * {@link #pixels}. Cleared per tile by the paint workers.
+ */
+ public float[] depth;
+
+ /**
+ * Active paint pass, set internally by
+ * {@code RenderAggregator.paintSorted}: 0 = not painting, 1 =
+ * opaque pass (opaque-class triangles only, depth test + write),
+ * 2 = alpha pass (alpha-carrying
+ * triangles only, depth test, no depth write). Shapes read it to
+ * decide whether they belong to the current pass.
+ */
+ public int depthPass;
+
+ /**
+ * Depth tolerance in world units for the z-buffer test, in the form
+ * {@code zw > stored - DEPTH_MARGIN_DZ * zw * zw} (tolerance behind
+ * stored, per-pixel at fragment depth). Default 0 = strict depth: any
+ * nonzero window exports per-triangle painter-sort errors into
+ * per-pixel occlusion errors (dirt whose triangles sort late beats
+ * road pavement that strictly wins at margin 0 — user bugreport
+ * 2026-09-16, road pose). Tunable via -Daukio.zbuffer.margin.
+ */
+ public static final double DEPTH_MARGIN_DZ =
+ Double.parseDouble(System.getProperty("aukio.zbuffer.margin", "0"));
+
+ /**
+ * Width of the rendering area in pixels.
+ */
+ public final int width;
+
+ /**
+ * Height of the rendering area in pixels.
+ */
+ public final int height;
+
+ /**
+ * Center of the screen in screen space (pixels).
+ * This is the point where (0,0) coordinate of the world space is rendered.
+ */
+ public final Point2D centerCoordinate;
+
+ /**
+ * Scale factor for perspective projection, derived from screen width.
+ * Used to convert normalized device coordinates to screen pixels.
+ * This is mutable to support stereo rendering where each eye has a different viewport width.
+ */
+ public double projectionScale;
+
+ /**
+ * Minimum Y coordinate (inclusive) to render. Used for multi-threaded rendering
+ * where each thread renders a horizontal segment.
+ */
+ public final int renderMinY;
+
+ /**
+ * Maximum Y coordinate (exclusive) to render. Used for multi-threaded rendering
+ * where each thread renders a horizontal segment.
+ */
+ public final int renderMaxY;
+
+ /** The backing image (public: the AWT shell in {@code gui} blits it directly). */
+ public final BufferedImage bufferedImage;
+ /**
+ * Unique id of the current transform cycle, assigned by
+ * {@code ShapeCollection.transformShapes()} from a global counter.
+ * Unlike {@link #frameNumber} (per-context, can repeat across context
+ * instances), this never collides, so per-cycle memoization such as
+ * composite subtree weights can safely key on it.
+ */
+ public long transformCycleId;
+
+ /**
+ * Which projection buffer slot this context writes/reads: 0, 1 or 2.
+ * Cycles per render pass (per eye in stereo) when the
+ * triple-buffered pipeline is active, so the transform phase of a
+ * pass never overwrites the vertex state either of the two previous
+ * passes' paints may still be reading. Always 0 when the pipeline is
+ * off (tests, single-pass rendering).
+ */
+ public int vertexSlot = 0;
+
+ /**
+ * Near-plane distance in camera-space Z units. Polygons whose vertices
+ * straddle this plane are clipped against it (new intersection vertices
+ * are generated with interpolated UVs); polygons fully behind it are
+ * culled. Must be > 0 so the perspective divide stays safe.
+ */
+ public double nearPlaneDistance = 1.0;
+
+ /**
+ * Number of frame that is currently being rendered.
+ * Every frame has its own number.
+ */
+ public int frameNumber = 0;
+
+ /**
+ * Projected-size cull threshold in screen pixels: shapes whose screen
+ * bounds span less than this in both axes are not queued for
+ * rendering. 0 (the default) disables the cull. Set globally with
+ * {@code -Daukio.cull.subpixel=<px>}.
+ */
+ public double subpixelCullingThreshold = Double.parseDouble(
+ System.getProperty("aukio.cull.subpixel", "0"));
+
+ /**
+ * Epoch of the subpixel-culling verdict cache, stamped per frame by
+ * {@code ShapeCollection.transformShapesBegin}: the epoch advances
+ * when the camera moves significantly (or after a bounded number of
+ * frames), which invalidates all cached skip verdicts and forces one
+ * re-evaluation pass. Meaningless when the cull is off.
+ */
+ public int subpixelCullingEpoch;
+
+ /**
+ * UI component that mouse is currently hovering over.
+ */
+ private MouseInteractionController objectPreviouslyUnderMouseCursor;
+ /**
+ * Mouse click event that needs to be processed.
+ * This event is processed only once per frame.
+ * If there are multiple objects under the mouse cursor, the top-most object will receive the event.
+ * If there are no objects under the mouse cursor, the event will be ignored.
+ * If there is no event, this field will be null.
+ * This field is set to null after the event is processed.
+ */
+ private MouseEvent mouseEvent;
+ /**
+ * UI component that mouse is currently hovering over.
+ */
+ private MouseInteractionController currentObjectUnderMouseCursor;
+ /**
+ * Texture coordinates of the mouse cursor on the hit shape (primary
+ * texture pixels), or NaN when the hit shape has no texture.
+ */
+ private double currentMouseTextureU = Double.NaN;
+ private double currentMouseTextureV = Double.NaN;
+ /**
+ * Developer tools for this rendering context.
+ * Controls diagnostic features like logging and visualization.
+ */
+ public DeveloperTools developerTools;
+
+ /**
+ * Debug log buffer for capturing diagnostic output.
+ * Shapes can log messages here that appear in the Developer Tools panel.
+ */
+ public DebugLogBuffer debugLogBuffer;
+
+ /**
+ * Global lighting manager for the scene.
+ * All shaded polygons use this to calculate lighting. Contains all light sources
+ * and ambient light settings for the world.
+ */
+ public LightingManager lightingManager;
+
+ /**
+ * Which eye is being rendered in stereo mode. NONE for normal single-view rendering.
+ */
+ public StereoEye stereoEye = StereoEye.NONE;
+
+ /**
+ * Width of the viewport for the current eye in stereo mode.
+ * Equals {@link #width} when not in stereo mode.
+ */
+ public int stereoViewportWidth;
+
+ /**
+ * X offset of the current eye's viewport within the full buffer.
+ * 0 for left eye, width/2 for right eye, 0 in normal mode.
+ */
+ public int stereoViewportOffsetX;
+
+ /**
+ * Minimum X coordinate (inclusive) for rendering.
+ * In stereo mode, this is {@link #stereoViewportOffsetX}.
+ * In normal mode, this is 0.
+ */
+ public int renderMinX;
+
+ /**
+ * Maximum X coordinate (exclusive) for rendering.
+ * In stereo mode, this is {@link #stereoViewportOffsetX} + {@link #stereoViewportWidth}.
+ * In normal mode, this is {@link #width}.
+ */
+ public int renderMaxX;
+
+ /**
+ * View frustum for frustum culling.
+ * Updated each frame from camera state and screen dimensions.
+ * Shapes can test their bounding boxes against this frustum to determine
+ * if they are potentially visible before expensive vertex transformations.
+ */
+ public Frustum frustum;
+
+ /**
+ * World-space position of the viewer for this pass, copied from the
+ * camera in {@link eu.svjatoslav.aukio.e3d.renderer.raster.ShapeCollection#transformShapesBegin}.
+ * Used by BSP painter ordering (viewpoint for tree traversal).
+ * Fresh instance per context, including per-pass copies, so overlapping
+ * pipeline passes each see their own viewpoint.
+ */
+ public final eu.svjatoslav.aukio.e3d.geometry.Point3D viewerPosition =
+ new eu.svjatoslav.aukio.e3d.geometry.Point3D();
+
+ /**
+ * Statistics for frustum culling performance tracking.
+ * Updated each frame: total shapes counted at start, visible shapes
+ * incremented during rendering, culled composites tracked during transform.
+ */
+ public CullingStatistics cullingStatistics;
+
+ /**
+ * Hi-Z occlusion pyramid, rebuilt from the depth buffer after every
+ * painted frame (live {@code ViewPanel} path only — headless
+ * {@code Snapshot} renders leave it empty so golden renders never
+ * cull). Read during the next frame's transform by
+ * {@code TriangleMeshBlock} to skip fully occluded blocks. Shared
+ * with pass/segment copies like {@link #depth}.
+ */
+ public HiZPyramid occlusionPyramid;
+
+ /**
+ * Executor for the parallel transform phase. When non-null, composites
+ * with enough children split their render lists into chunks transformed
+ * concurrently. When null, the transform phase runs serially on the
+ * render thread.
+ */
+ public ExecutorService transformExecutor;
+
+ /**
+ * Per-frame coordinator for the non-blocking parallel transform fork.
+ * Set by {@code ShapeCollection.transformShapes()} for the duration of
+ * the root transform when {@link #transformExecutor} is available;
+ * composites at any nesting level submit chunk tasks to it. Null outside
+ * the transform phase and when transforming serially.
+ */
+ public ParallelTransformCoordinator transformCoordinator;
+
+ /**
+ * Present gate for this framebuffer: fires when the frame currently
+ * held in this buffer has been presented to the display (or dropped
+ * from the presentation mailbox). The render thread installs a fresh
+ * gate at the start of each frame that reuses the buffer, and the
+ * frame's paint continuation awaits the PREVIOUS gate before writing
+ * pixels — without it, painting frame F+3 would overwrite the buffer
+ * while the present thread is still blitting frame F from it.
+ */
+ public volatile java.util.concurrent.CountDownLatch presentGate = new java.util.concurrent.CountDownLatch(0);
+
+ /**
+ * Chunk tasks submitted during the last transform phase, across all
+ * nesting levels. Diagnostics: proves nested composites forked.
+ */
+ public int lastTransformTaskCount;
+
+ /**
+ * Creates a new rendering context for full-screen rendering.
+ *
+ * <p>Equivalent to {@code RenderingContext(width, height, 0, height, numRenderSegments)}.</p>
+ *
+ * @param width the rendering area width in pixels
+ * @param height the rendering area height in pixels
+ * @param numRenderSegments number of parallel render segments (threads)
+ */
+ public RenderingContext(final int width, final int height, final int numRenderSegments) {
+ this(width, height, 0, height, 1, numRenderSegments, 1);
+ }
+
+ /**
+ * Creates a new rendering context with a rectangular tile grid.
+ *
+ * <p>Equivalent to the band-only constructors when {@code tilesX == 1}.
+ * In stereo mode ({@code viewportCount == 2}) each viewport gets its own
+ * tile grid; segment indices for viewport v start at
+ * {@code v * tilesX * tilesY}.</p>
+ *
+ * @param width the rendering area width in pixels
+ * @param height the rendering area height in pixels
+ * @param tilesX tile columns per viewport (1 = bands only)
+ * @param tilesY tile rows per viewport
+ * @param viewportCount number of side-by-side viewports (2 = stereo)
+ */
+ public RenderingContext(final int width, final int height,
+ final int tilesX, final int tilesY,
+ final int viewportCount) {
+ this(width, height, 0, height, tilesX, tilesY, viewportCount);
+ }
+
+ private RenderingContext(final int width, final int height,
+ final int renderMinY, final int renderMaxY,
+ final int tilesX, final int tilesY,
+ final int viewportCount) {
+ this.width = width;
+ this.height = height;
+ this.renderMinY = renderMinY;
+ this.renderMaxY = renderMaxY;
+ this.tilesX = tilesX;
+ this.tilesY = tilesY;
+ this.viewportCount = viewportCount;
+ this.numRenderSegments = tilesX * tilesY * viewportCount;
+ this.centerCoordinate = new Point2D(width / 2d, height / 2d);
+ this.projectionScale = width / 3d;
+ this.stereoViewportWidth = width;
+ this.stereoViewportOffsetX = 0;
+ this.renderMinX = 0;
+ this.renderMaxX = width;
+
+ // Eagerly allocated so the developer-tools panel always finds it:
+ // transformPass() hands the pipeline a per-pass COPY of this context,
+ // and the copy constructor shares this reference. Lazy creation in
+ // ShapeCollection.transformShapesBegin() would only ever populate the
+ // throwaway pass copy, leaving this frame context null forever
+ // (the culling display then showed "-" permanently).
+ this.cullingStatistics = new CullingStatistics();
+ this.occlusionPyramid = new HiZPyramid();
+
+ bufferedImage = new BufferedImage(width, height, bufferedImageType);
+
+ final WritableRaster raster = bufferedImage.getRaster();
+ final DataBufferInt dbi = (DataBufferInt) raster.getDataBuffer();
+ pixels = dbi.getData();
+
+ // Z-buffer: one w-depth (biased 1/z) value per pixel, cleared per
+ // tile in the paint workers. Depth turns the queue order into a
+ // performance heuristic only; correctness comes from the per-pixel
+ // test. (The queue itself stays painter back-to-front — Z
+ // descending, see RenderAggregator.) Always allocated: the
+ // z-buffer path is the only renderer.
+ depth = new float[width * height];
+
+ graphics = (Graphics2D) bufferedImage.getGraphics();
+ graphics.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
+ graphics.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
+
+ segmentGraphics = createSegmentGraphics();
+ }
+
+ /**
+ * Protected constructor for creating segment views.
+ * Shares the pixel buffer and graphics context with the parent.
+ *
+ * @param parent the parent rendering context
+ * @param renderMinY minimum Y coordinate (inclusive) for this segment
+ * @param renderMaxY maximum Y coordinate (exclusive) for this segment
+ */
+ protected RenderingContext(final RenderingContext parent,
+ final int renderMinY, final int renderMaxY) {
+ this.width = parent.width;
+ this.height = parent.height;
+ this.renderMinY = renderMinY;
+ this.renderMaxY = renderMaxY;
+ this.tilesX = parent.tilesX;
+ this.tilesY = parent.tilesY;
+ this.viewportCount = parent.viewportCount;
+ this.numRenderSegments = parent.numRenderSegments;
+ this.centerCoordinate = parent.centerCoordinate;
+ this.projectionScale = parent.projectionScale;
+ this.stereoViewportWidth = parent.stereoViewportWidth;
+ this.stereoViewportOffsetX = parent.stereoViewportOffsetX;
+ this.stereoEye = parent.stereoEye;
+ this.renderMinX = parent.renderMinX;
+ this.renderMaxX = parent.renderMaxX;
+ this.bufferedImage = parent.bufferedImage;
+ this.pixels = parent.pixels;
+ this.depth = parent.depth;
+ this.graphics = parent.graphics;
+ this.vertexSlot = parent.vertexSlot;
+ this.nearPlaneDistance = parent.nearPlaneDistance;
+ this.developerTools = parent.developerTools;
+ this.debugLogBuffer = parent.debugLogBuffer;
+ this.lightingManager = parent.lightingManager;
+ this.occlusionPyramid = parent.occlusionPyramid;
+ this.segmentGraphics = null;
+ }
+
+ /**
+ * Creates an independent pass context for one pipeline pass (one eye
+ * in stereo): shares the frame's pixel buffer, graphics and services,
+ * but owns the per-pass projection fields (center, scale, stereo
+ * viewport, slot, frame/cycle stamps). The next pass's setup writes
+ * to its own copy, so it cannot disturb this pass's in-flight
+ * transform chunks or its asynchronous sort/bin/paint continuation.
+ *
+ * @param parent the frame rendering context to copy from
+ */
+ public RenderingContext(final RenderingContext parent) {
+ this.width = parent.width;
+ this.height = parent.height;
+ this.renderMinY = parent.renderMinY;
+ this.renderMaxY = parent.renderMaxY;
+ this.tilesX = parent.tilesX;
+ this.tilesY = parent.tilesY;
+ this.viewportCount = parent.viewportCount;
+ this.numRenderSegments = parent.numRenderSegments;
+ this.centerCoordinate = new Point2D(parent.centerCoordinate.x, parent.centerCoordinate.y);
+ this.projectionScale = parent.projectionScale;
+ this.stereoViewportWidth = parent.stereoViewportWidth;
+ this.stereoViewportOffsetX = parent.stereoViewportOffsetX;
+ this.stereoEye = parent.stereoEye;
+ this.renderMinX = parent.renderMinX;
+ this.renderMaxX = parent.renderMaxX;
+ this.bufferedImage = parent.bufferedImage;
+ this.pixels = parent.pixels;
+ this.depth = parent.depth;
+ this.graphics = parent.graphics;
+ this.vertexSlot = parent.vertexSlot;
+ this.nearPlaneDistance = parent.nearPlaneDistance;
+ this.frameNumber = parent.frameNumber;
+ this.transformCycleId = parent.transformCycleId;
+ this.transformExecutor = parent.transformExecutor;
+ this.developerTools = parent.developerTools;
+ this.debugLogBuffer = parent.debugLogBuffer;
+ this.lightingManager = parent.lightingManager;
+ this.cullingStatistics = parent.cullingStatistics;
+ this.occlusionPyramid = parent.occlusionPyramid;
+ this.subpixelCullingThreshold = parent.subpixelCullingThreshold;
+ this.subpixelCullingEpoch = parent.subpixelCullingEpoch;
+ this.setMouseEvent(parent.getMouseEvent());
+ // Share the pre-clipped per-tile graphics: glyph rendering
+ // (user-facing text) draws through them by segment index. Null
+ // here made every glyph paint die with an NPE mid-tile (broken
+ // tiles whenever text faced the reader).
+ this.segmentGraphics = parent.segmentGraphics;
+ // frustum stays null: created fresh per pass in transformShapesBegin
+ }
+
+ /**
+ * Resets per-frame state in preparation for rendering a new frame.
+ * Increments the frame number and clears the mouse event state.
+ */
+ public void prepareForNewFrameRendering() {
+ frameNumber++;
+ mouseEvent = null;
+ currentObjectUnderMouseCursor = null;
+ }
+
+ /**
+ * Creates Graphics2D contexts for each render segment, pre-clipped to
+ * its tile rectangle. Segment index layout: viewport v, tile row ty,
+ * tile column tx -> v * tilesX * tilesY + ty * tilesX + tx.
+ *
+ * @return array of Graphics2D objects, one per segment
+ */
+ private Graphics2D[] createSegmentGraphics() {
+ final Graphics2D[] contexts = new Graphics2D[numRenderSegments];
+ final int viewportWidth = width / viewportCount;
+ final int tileW = viewportWidth / tilesX;
+ final int tileH = height / tilesY;
+
+ for (int v = 0; v < viewportCount; v++) {
+ final int viewportX = v * viewportWidth;
+ for (int ty = 0; ty < tilesY; ty++) {
+ final int minY = ty * tileH;
+ final int maxY = (ty == tilesY - 1) ? height : (ty + 1) * tileH;
+ for (int tx = 0; tx < tilesX; tx++) {
+ final int minX = viewportX + tx * tileW;
+ final int maxX = (tx == tilesX - 1)
+ ? viewportX + viewportWidth : minX + tileW;
+
+ final Graphics2D g = bufferedImage.createGraphics();
+ g.setClip(minX, minY, maxX - minX, maxY - minY);
+ g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
+ g.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
+ contexts[v * tilesX * tilesY + ty * tilesX + tx] = g;
+ }
+ }
+ }
+
+ return contexts;
+ }
+
+ /**
+ * Returns the backing image whose pixel buffer the rasterizer paints into.
+ *
+ * <p>Exposed for headless rendering: after a transform/sort/paint pass the
+ * image holds the finished frame and can be saved or compared directly.</p>
+ *
+ * @return the backing buffered image
+ */
+ public BufferedImage getImage() {
+ return bufferedImage;
+ }
+
+ /**
+ * Returns the Graphics2D context for a specific render segment.
+ * Each segment's Graphics2D is pre-clipped to its Y bounds.
+ *
+ * @param segmentIndex the segment index (0 to numRenderSegments-1)
+ * @return the Graphics2D for that segment
+ * @throws NullPointerException if called on a segment view (not the main context)
+ */
+ public Graphics2D getSegmentGraphics(final int segmentIndex) {
+ return segmentGraphics[segmentIndex];
+ }
+
+ /**
+ * Disposes all Graphics2D resources associated with this context.
+ * Should be called when the context is no longer needed (e.g., on resize).
+ */
+ public void dispose() {
+ if (segmentGraphics != null) {
+ for (final Graphics2D g : segmentGraphics) {
+ if (g != null) {
+ g.dispose();
+ }
+ }
+ }
+ if (graphics != null) {
+ graphics.dispose();
+ }
+ }
+
+ /**
+ * Executes a graphics operation in a thread-safe manner.
+ * This must be used for all Graphics2D operations (text, lines, etc.)
+ * during multi-threaded rendering.
+ *
+ * @param operation the graphics operation to execute
+ */
+ public void executeWithGraphics(final Consumer<Graphics2D> operation) {
+ synchronized (graphics) {
+ operation.accept(graphics);
+ }
+ }
+
+ /**
+ * Returns the pending mouse event for this frame, or {@code null} if none.
+ *
+ * @return the mouse event to process, or {@code null}
+ */
+ public MouseEvent getMouseEvent() {
+ return mouseEvent;
+ }
+
+ /**
+ * Sets the mouse event to be processed during this frame's rendering.
+ *
+ * @param mouseEvent the mouse event with position and button information
+ */
+ public void setMouseEvent(MouseEvent mouseEvent) {
+ this.mouseEvent = mouseEvent;
+ }
+
+ /**
+ * Called when given object was detected under mouse cursor, while processing {@link #mouseEvent}.
+ * Because objects are rendered back to front. The last method caller will set the top-most object, if
+ * there are multiple objects under mouse cursor.
+ *
+ * @param currentObjectUnderMouseCursor the object that is currently under the mouse cursor
+ */
+ public synchronized void setCurrentObjectUnderMouseCursor(MouseInteractionController currentObjectUnderMouseCursor) {
+ setCurrentObjectUnderMouseCursor(currentObjectUnderMouseCursor,
+ Double.NaN, Double.NaN);
+ }
+
+ /**
+ * Called when given object was detected under mouse cursor, with the
+ * texture coordinates of the hit point (for textured shapes).
+ *
+ * @param currentObjectUnderMouseCursor the object under the mouse cursor
+ * @param textureU texture-space X of the hit point in primary-texture pixels
+ * @param textureV texture-space Y of the hit point in primary-texture pixels
+ */
+ public synchronized void setCurrentObjectUnderMouseCursor(
+ final MouseInteractionController currentObjectUnderMouseCursor,
+ final double textureU, final double textureV) {
+ this.currentObjectUnderMouseCursor = currentObjectUnderMouseCursor;
+ this.currentMouseTextureU = textureU;
+ this.currentMouseTextureV = textureV;
+ }
+
+ /**
+ * Returns the current object under the mouse cursor.
+ * Used by segment rendering to collect mouse results.
+ *
+ * @return the current object under mouse cursor, or null
+ */
+ public synchronized MouseInteractionController getCurrentObjectUnderMouseCursor() {
+ return currentObjectUnderMouseCursor;
+ }
+
+ /**
+ * Handles mouse events for components and returns whether a view repaint is needed.
+ *
+ * @param focusStack keyboard focus stack of the dispatching view, handed
+ * to clicked components so they can acquire focus
+ * without holding a ViewPanel reference
+ * @return {@code true} if view update is needed as a consequence of this mouse event
+ */
+ public boolean handlePossibleComponentMouseEvent(final KeyboardFocusStack focusStack) {
+ if (mouseEvent == null) return false;
+
+ boolean viewRepaintNeeded = false;
+
+ if (objectPreviouslyUnderMouseCursor != currentObjectUnderMouseCursor) {
+ // Mouse cursor has just entered or left component.
+ viewRepaintNeeded = objectPreviouslyUnderMouseCursor != null && objectPreviouslyUnderMouseCursor.mouseExited();
+ viewRepaintNeeded |= currentObjectUnderMouseCursor != null && currentObjectUnderMouseCursor.mouseEntered();
+ objectPreviouslyUnderMouseCursor = currentObjectUnderMouseCursor;
+ }
+
+ if (mouseEvent.button != 0 && currentObjectUnderMouseCursor != null) {
+ // Mouse button was clicked on some component.
+ viewRepaintNeeded |= currentObjectUnderMouseCursor.mouseClicked(
+ mouseEvent.button, currentMouseTextureU, currentMouseTextureV,
+ focusStack);
+ } else if (currentObjectUnderMouseCursor != null)
+ // hover: let the component track the pointer position
+ viewRepaintNeeded |= currentObjectUnderMouseCursor.mouseHover(
+ currentMouseTextureU, currentMouseTextureV);
+
+ return viewRepaintNeeded;
+ }
+
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster;
+
+import eu.svjatoslav.aukio.e3d.gui.humaninput.MouseEvent;
+import eu.svjatoslav.aukio.e3d.gui.humaninput.MouseInteractionController;
+
+import java.awt.*;
+import java.util.function.Consumer;
+
+/**
+ * A view of a RenderingContext for rendering a horizontal screen segment.
+ *
+ * <p>This class wraps a parent RenderingContext and provides its own Y-bounds
+ * for multi-threaded rendering. All operations delegate to the parent context,
+ * but with segment-specific Y bounds for pixel operations.</p>
+ *
+ * <p>Mouse tracking is local to each segment and must be combined after all
+ * segments complete rendering.</p>
+ *
+ * @see RenderingContext
+ */
+public class SegmentRenderingContext extends RenderingContext {
+
+ private final RenderingContext parent;
+ private final int segmentIndex;
+ private MouseInteractionController segmentMouseHit;
+ private double segmentMouseHitU = Double.NaN;
+ private double segmentMouseHitV = Double.NaN;
+
+ /**
+ * Creates a segment view of a parent rendering context.
+ *
+ * @param parent the parent rendering context to delegate to
+ * @param renderMinY minimum Y coordinate (inclusive) for this segment
+ * @param renderMaxY maximum Y coordinate (exclusive) for this segment
+ * @param segmentIndex the index of this segment (0 to numRenderSegments-1)
+ */
+ public SegmentRenderingContext(final RenderingContext parent,
+ final int renderMinY, final int renderMaxY,
+ final int segmentIndex) {
+ super(parent, renderMinY, renderMaxY);
+ this.parent = parent;
+ this.segmentIndex = segmentIndex;
+ }
+
+ @Override
+ public void executeWithGraphics(final Consumer<Graphics2D> operation) {
+ operation.accept(parent.getSegmentGraphics(segmentIndex));
+ }
+
+ @Override
+ public MouseEvent getMouseEvent() {
+ return parent.getMouseEvent();
+ }
+
+ @Override
+ public void setMouseEvent(final MouseEvent mouseEvent) {
+ parent.setMouseEvent(mouseEvent);
+ }
+
+ @Override
+ public synchronized void setCurrentObjectUnderMouseCursor(final MouseInteractionController controller) {
+ setCurrentObjectUnderMouseCursor(controller, Double.NaN, Double.NaN);
+ }
+
+ @Override
+ public synchronized void setCurrentObjectUnderMouseCursor(
+ final MouseInteractionController controller,
+ final double textureU, final double textureV) {
+ this.segmentMouseHit = controller;
+ this.segmentMouseHitU = textureU;
+ this.segmentMouseHitV = textureV;
+ }
+
+ /**
+ * Returns the mouse hit detected in this segment.
+ *
+ * @return the MouseInteractionController that was under the mouse in this segment, or null
+ */
+ public MouseInteractionController getSegmentMouseHit() {
+ return segmentMouseHit;
+ }
+
+ /**
+ * Texture-space X of the hit point (primary texture pixels), NaN if none.
+ */
+ public double getSegmentMouseHitU() {
+ return segmentMouseHitU;
+ }
+
+ /**
+ * Texture-space Y of the hit point (primary texture pixels), NaN if none.
+ */
+ public double getSegmentMouseHitV() {
+ return segmentMouseHitV;
+ }
+
+ @Override
+ public synchronized MouseInteractionController getCurrentObjectUnderMouseCursor() {
+ return segmentMouseHit;
+ }
+}
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.geometry.Camera;
+import eu.svjatoslav.aukio.e3d.math.Quaternion;
+import eu.svjatoslav.aukio.e3d.math.Transform;
+import eu.svjatoslav.aukio.e3d.math.TransformStack;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.AbstractCoordinateShape;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.AbstractShape;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.SubShape;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.concurrent.ExecutorService;
+
+/**
+ * Root container that holds all 3D shapes in a scene and orchestrates their rendering.
+ *
+ * <p>{@code ShapeCollection} is the top-level scene graph. You add shapes to it, and during
+ * each render frame it transforms all shapes from world space to screen space (relative to the
+ * camera), sorts them by depth, and paints them back-to-front.</p>
+ *
+ * <p><b>Architecture:</b></p>
+ * <p>The collection contains a single {@link AbstractCompositeShape} as its root container.
+ * This root composite:</p>
+ * <ul>
+ * <li>Stores all scene shapes in its sub-shapes registry</li>
+ * <li>Triangulates N-vertex polygons (quads, etc.) into triangles during rendering</li>
+ * <li>Provides group-based visibility management (show/hide groups)</li>
+ * <li>Applies camera transform (position and rotation) to all shapes</li>
+ * </ul>
+ *
+ * <p><b>Usage example:</b></p>
+ * <pre>{@code
+ * // Get the root shape collection from the view panel
+ * ShapeCollection scene = viewPanel.getRootShapeCollection();
+ *
+ * // Add shapes to the scene
+ * scene.addShape(new Line(
+ * new Point3D(0, 0, 100),
+ * new Point3D(100, 0, 100),
+ * Color.RED, 2.0
+ * ));
+ *
+ * // Add shapes with group identifier for visibility control
+ * scene.addShape(debugShape, "debug");
+ * scene.hideGroup("debug"); // hide all debug shapes
+ * scene.showGroup("debug"); // show them again
+ *
+ * // Add N-vertex polygons (quads, etc.) - automatically triangulated
+ * scene.addShape(SolidPolygon.quad(p1, p2, p3, p4, color));
+ * }</pre>
+ *
+ * <p>The {@link #addShape} method is synchronized, making it safe to add shapes from
+ * any thread while the rendering loop is active.</p>
+ *
+ * @see eu.svjatoslav.aukio.e3d.gui.ViewPanel#getRootShapeCollection()
+ * @see AbstractShape the base class for all shapes
+ * @see AbstractCompositeShape the root composite that stores and processes all shapes
+ * @see RenderAggregator handles depth sorting and painting
+ */
+public class ShapeCollection {
+
+ /**
+ * Render aggregators that collect transformed shapes, sort by depth, and
+ * paint — one per projection buffer slot. The double-buffered pipeline
+ * fills one slot's aggregator during transform while the other slot's
+ * aggregator is still being painted. Slot 0 serves all single-buffered
+ * (serial) rendering.
+ */
+ private final RenderAggregator[] aggregators = { new RenderAggregator(0), new RenderAggregator(1),
+ new RenderAggregator(2) };
+
+ /**
+ * The transform stack used during the rendering pipeline.
+ */
+ private final TransformStack transformStack = new TransformStack();
+
+ /**
+ * Global transform-cycle counter; each transform pass gets a unique id
+ * for per-cycle memoization (composite subtree weights).
+ */
+ private long transformCycleCounter;
+
+ // Subpixel-culling verdict cache state (only advanced when the cull
+ // is enabled on the pass context): the epoch bumps on significant
+ // camera change, and unconditionally every CULL_MAX_FRAMES frames so
+ // shape-side transform changes cannot hide behind a stale verdict.
+ private static final double CULL_TRANSLATE_DELTA = Double.parseDouble(
+ System.getProperty("aukio.cull.subpixel.translate", "25"));
+ private static final double CULL_ROTATE_DELTA = Double.parseDouble(
+ System.getProperty("aukio.cull.subpixel.rotate", "0.01"));
+ private static final int CULL_MAX_FRAMES = Integer.parseInt(
+ System.getProperty("aukio.cull.subpixel.frames", "30"));
+ private int subpixelCullingEpoch;
+ private int cullEpochAge;
+ private double cullCamX = Double.NaN;
+ private double cullCamY;
+ private double cullCamZ;
+ private double cullCamQw;
+ private double cullCamQx;
+ private double cullCamQy;
+ private double cullCamQz;
+
+
+ // Camera rotation. We reuse this object for every frame render to avoid garbage collections.
+ private final Transform cameraRotationTransform = new Transform();
+
+ // Camera rotation. We reuse this object for every frame render to avoid garbage collections.
+ private final Transform cameraTranslationTransform = new Transform();
+
+ /**
+ * Root composite shape containing all scene shapes.
+ *
+ * <p>Handles:</p>
+ * <ul>
+ * <li>N-gon triangulation (quads → triangles)</li>
+ * <li>Group-based visibility management</li>
+ * <li>Camera transform application</li>
+ * <li>LOD slicing for nested composites</li>
+ * </ul>
+ *
+ * <p>The transform is updated each frame to match the camera position and rotation.</p>
+ */
+ private final AbstractCompositeShape rootComposite;
+
+ /**
+ * Creates a new empty shape collection with a root composite.
+ */
+ public ShapeCollection() {
+ rootComposite = new AbstractCompositeShape();
+ rootComposite.setRootComposite(true);
+ }
+
+ /**
+ * Adds a shape to this collection without a group identifier. This method is thread-safe.
+ *
+ * @param shape the shape to add to the scene
+ */
+ public synchronized void addShape(final AbstractShape shape) {
+ rootComposite.addShape(shape);
+ }
+
+ /**
+ * Collects the triangles currently rendered for this collection (render
+ * lists of all composites, recursively). Used by derived structures like
+ * the global-illumination scene snapshot. Render lists build lazily
+ * during transform, so the result may be empty until the first frame.
+ *
+ * @param out list receiving the polygons
+ */
+ public void collectRenderTriangles(final List<eu.svjatoslav.aukio.e3d.renderer.raster.shapes.AbstractCoordinateShape> out) {
+ rootComposite.collectRenderTriangles(out);
+ }
+
+ /**
+ * Adds a shape to this collection with a group identifier for visibility control. This method is thread-safe.
+ *
+ * <p>Grouped shapes can be shown, hidden, or removed together using
+ * {@link #showGroup}, {@link #hideGroup}, and {@link #removeGroup}.</p>
+ *
+ * @param shape the shape to add
+ * @param groupId the group identifier, or {@code null} for ungrouped shapes
+ */
+ public synchronized void addShape(final AbstractShape shape, final String groupId) {
+ rootComposite.addShape(shape, groupId);
+ }
+
+ /**
+ * Returns all shapes currently in this collection (including hidden ones).
+ *
+ * <p>This returns the sub-shapes from the registry, unwrapped from their {@link SubShape}
+ * containers. For access to group and visibility metadata, use {@link #getSubShapesRegistry()}.</p>
+ *
+ * @return a collection of all shapes in the scene
+ */
+ public Collection<AbstractShape> getShapes() {
+ final List<AbstractShape> result = new ArrayList<>();
+ for (final SubShape subShape : rootComposite.getSubShapesRegistry()) {
+ result.add(subShape.getShape());
+ }
+ return result;
+ }
+
+ /**
+ * Returns the sub-shapes registry with group and visibility metadata.
+ *
+ * <p>This provides direct access to the registry for advanced operations
+ * like inspecting group assignments or visibility states.</p>
+ *
+ * @return the list of sub-shapes with their metadata
+ */
+ public List<SubShape> getSubShapesRegistry() {
+ return rootComposite.getSubShapesRegistry();
+ }
+
+ /**
+ * Removes all shapes from this collection. This method is thread-safe.
+ */
+ public synchronized void clear() {
+ rootComposite.getSubShapesRegistry().clear();
+ rootComposite.setCacheNeedsRebuild(true);
+ }
+
+ /**
+ * Shows all shapes belonging to the specified group.
+ *
+ * @param groupId the group identifier to show
+ */
+ public void showGroup(final String groupId) {
+ rootComposite.showGroup(groupId);
+ }
+
+ /**
+ * Hides all shapes belonging to the specified group.
+ * Hidden shapes are not rendered but remain in the collection.
+ *
+ * @param groupId the group identifier to hide
+ */
+ public void hideGroup(final String groupId) {
+ rootComposite.hideGroup(groupId);
+ }
+
+ /**
+ * Permanently removes all shapes belonging to the specified group.
+ *
+ * @param groupId the group identifier to remove
+ */
+ public void removeGroup(final String groupId) {
+ rootComposite.removeGroup(groupId);
+ }
+
+ /**
+ * Returns all sub-shapes belonging to the specified group.
+ *
+ * @param groupId the group identifier to match
+ * @return list of matching sub-shapes
+ */
+ public List<SubShape> getGroup(final String groupId) {
+ return rootComposite.getGroup(groupId);
+ }
+
+ /**
+ * Transforms all shapes to screen space and queues them for rendering.
+ * This is phase 1 of the multi-threaded render pipeline.
+ *
+ * <p>Updates the root composite's transform to match the camera position and rotation,
+ * then delegates to the root composite's transform method which handles all shapes.</p>
+ *
+ * <p><b>Frustum culling:</b> The view frustum is computed from camera state and
+ * screen dimensions before transforming shapes. Composite shapes can test their
+ * bounding boxes against this frustum to skip invisible objects.</p>
+ *
+ * <p><b>Culling statistics:</b> Statistics are reset and total shape count computed
+ * at the start of each frame. Visible shapes are counted as they are queued.</p>
+ *
+ * @param viewPanel the view panel providing the camera state
+ * @param renderingContext the rendering context with frame metadata
+ */
+ /**
+ * Camera-based variant of {@link #transformShapes(Camera, RenderingContext)}
+ * for headless rendering without a {@link eu.svjatoslav.aukio.e3d.gui.ViewPanel} (off-screen snapshots,
+ * golden-image tests, GI scene setup).
+ *
+ * @param camera the camera providing position and orientation
+ * @param renderingContext the rendering context with frame metadata
+ */
+ public synchronized void transformShapes(final Camera camera,
+ final RenderingContext renderingContext) {
+ transformShapesBegin(camera, renderingContext);
+ drainTransformShapes(renderingContext);
+ }
+
+ /**
+ * Camera-based variant of {@link #transformShapesBegin(Camera, RenderingContext)}
+ * for headless rendering without a {@link eu.svjatoslav.aukio.e3d.gui.ViewPanel}.
+ *
+ * @param camera the camera providing position and orientation
+ * @param renderingContext the pass rendering context
+ */
+ public synchronized void transformShapesBegin(final Camera camera,
+ final RenderingContext renderingContext) {
+
+ final RenderAggregator aggregator = aggregators[renderingContext.vertexSlot];
+ aggregator.reset();
+ transformStack.clear();
+ renderingContext.transformCycleId = ++transformCycleCounter;
+
+ // Update frustum for this frame (used for frustum culling)
+ if (renderingContext.frustum == null) {
+ renderingContext.frustum = new Frustum();
+ }
+ renderingContext.frustum.update(camera, renderingContext.stereoViewportWidth, renderingContext.height);
+
+ // Initialize culling statistics for this frame
+ if (renderingContext.cullingStatistics == null) {
+ renderingContext.cullingStatistics = new CullingStatistics();
+ }
+ renderingContext.cullingStatistics.reset();
+ // Note: totalShapes will be counted during rendering as shapes are queued
+ // This ensures we count actual rendered primitives (after triangulation/slicing)
+
+ // final Transform rootTransform = rootComposite.getTransform();
+ // TODO: Investigate if this transform can be reused instead of solution below
+
+ cameraRotationTransform.getRotation().set(camera.getTransform().getRotation());
+ cameraRotationTransform.invalidateCache();
+ transformStack.addTransform(cameraRotationTransform);
+
+ final Point3D cameraLocation = camera.getTransform().getTranslation();
+ renderingContext.viewerPosition.x = cameraLocation.x;
+ renderingContext.viewerPosition.y = cameraLocation.y;
+ renderingContext.viewerPosition.z = cameraLocation.z;
+
+ // Advance the subpixel-culling verdict epoch when the camera has
+ // moved significantly since the last bump (translation in world
+ // units; rotation compared on quaternion components, 0.01 ~ 1.1
+ // degrees), or periodically. While the epoch holds, culled shapes
+ // skip their entire transform setup.
+ if (renderingContext.subpixelCullingThreshold > 0) {
+ final Quaternion camRot = camera.getTransform().getRotation();
+ final boolean moved = Double.isNaN(cullCamX)
+ || Math.abs(cameraLocation.x - cullCamX) > CULL_TRANSLATE_DELTA
+ || Math.abs(cameraLocation.y - cullCamY) > CULL_TRANSLATE_DELTA
+ || Math.abs(cameraLocation.z - cullCamZ) > CULL_TRANSLATE_DELTA
+ || Math.abs(camRot.w - cullCamQw) > CULL_ROTATE_DELTA
+ || Math.abs(camRot.x - cullCamQx) > CULL_ROTATE_DELTA
+ || Math.abs(camRot.y - cullCamQy) > CULL_ROTATE_DELTA
+ || Math.abs(camRot.z - cullCamQz) > CULL_ROTATE_DELTA;
+ if (moved || ++cullEpochAge >= CULL_MAX_FRAMES) {
+ subpixelCullingEpoch++;
+ cullEpochAge = 0;
+ cullCamX = cameraLocation.x;
+ cullCamY = cameraLocation.y;
+ cullCamZ = cameraLocation.z;
+ cullCamQw = camRot.w;
+ cullCamQx = camRot.x;
+ cullCamQy = camRot.y;
+ cullCamQz = camRot.z;
+ }
+ renderingContext.subpixelCullingEpoch = subpixelCullingEpoch;
+ }
+ cameraTranslationTransform.getTranslation().x = -cameraLocation.x;
+ cameraTranslationTransform.getTranslation().y = -cameraLocation.y;
+ cameraTranslationTransform.getTranslation().z = -cameraLocation.z;
+ transformStack.addTransform(cameraTranslationTransform);
+
+ // Non-blocking parallel fork: composites with enough children (at
+ // any nesting level) submit chunk tasks to the coordinator instead
+ // of transforming serially. The orchestrating thread (this one) is
+ // the only one allowed to block on task completion.
+ if (renderingContext.transformExecutor != null) {
+ renderingContext.transformCoordinator =
+ new ParallelTransformCoordinator(renderingContext.transformExecutor);
+ }
+ try {
+ rootComposite.transform(transformStack, aggregator, renderingContext);
+ } catch (final RuntimeException e) {
+ drainTransformShapes(renderingContext);
+ throw e;
+ }
+ }
+
+ /**
+ * Second half of {@link #transformShapes}: waits for all transform
+ * chunk tasks and merges their aggregators into the frame's root
+ * aggregator. Safe to call from a worker thread while the render
+ * thread already walks the NEXT pass: chunk tasks capture their own
+ * transform-stack snapshots, and the aggregator is addressed by the
+ * pass's projection slot, so passes never touch the same state.
+ *
+ * @param renderingContext the pass rendering context
+ */
+ public void drainTransformShapes(final RenderingContext renderingContext) {
+ if (renderingContext.transformCoordinator != null) {
+ renderingContext.transformCoordinator.drainAndMergeInto(
+ aggregators[renderingContext.vertexSlot]);
+ renderingContext.lastTransformTaskCount =
+ renderingContext.transformCoordinator.getSubmittedTaskCount();
+ renderingContext.transformCoordinator = null;
+ }
+ }
+
+ /**
+ * Sorts all queued shapes by Z-depth (back to front).
+ * This is phase 2 of the multi-threaded render pipeline.
+ */
+ public void sortShapes() {
+ aggregators[0].sort();
+ }
+
+ /**
+ * Sorts the given buffer slot's queued shapes by Z-depth.
+ *
+ * @param slot buffer slot to sort (0..2)
+ */
+ public void sortShapes(final int slot) {
+ aggregators[slot].sort();
+ }
+
+ /**
+ * Sorts the given buffer slot's queued shapes by Z-depth, parallelized
+ * over the given executor (instrumented parallel merge sort).
+ *
+ * @param slot buffer slot to sort
+ * @param executor executor for parallel sorting
+ */
+ public void sortShapes(final int slot, final java.util.concurrent.ExecutorService executor) {
+ aggregators[slot].sort(executor);
+ }
+
+ /**
+ * Bins the sorted render queue per rectangular paint tile by
+ * screen-space overlap, so each paint thread iterates only the
+ * shapes that can touch its tile instead of the whole queue.
+ * Call after {@link #sortShapes()}, before tile painting.
+ *
+ * @param tilesX tile columns across the viewport
+ * @param tilesY tile rows down the viewport
+ * @param originX X origin of the tiled viewport (eye offset in stereo)
+ * @param width tiled viewport width in pixels
+ * @param height full render height in pixels
+ * @param executor executor for parallel binning, or null for serial
+ */
+ public void binShapesForTiles(final int tilesX, final int tilesY,
+ final int originX, final int width, final int height,
+ final ExecutorService executor) {
+ aggregators[0].binForTiles(tilesX, tilesY, originX, width, height, executor);
+ }
+
+ /**
+ * Slot-selecting variant of
+ * {@link #binShapesForTiles(int, int, int, int, int, ExecutorService)}
+ * for the triple-buffered pipeline.
+ *
+ * @param slot buffer slot whose queue gets binned (0..2)
+ * @param tilesX tile columns across the viewport
+ * @param tilesY tile rows down the viewport
+ * @param originX X origin of the tiled viewport (eye offset in stereo)
+ * @param width tiled viewport width in pixels
+ * @param height full render height in pixels
+ * @param executor executor for parallel binning, or null for serial
+ */
+ public void binShapesForTiles(final int slot, final int tilesX, final int tilesY,
+ final int originX, final int width, final int height,
+ final ExecutorService executor) {
+ aggregators[slot].binForTiles(tilesX, tilesY, originX, width, height, executor);
+ }
+
+ /**
+ * Paints all already-sorted shapes to the rendering context.
+ * This is phase 3 of the multi-threaded render pipeline.
+ * Can be called multiple times with different segment contexts.
+ *
+ * @param renderingContext the rendering context to paint into
+ */
+ public void paintShapes(final RenderingContext renderingContext) {
+ aggregators[renderingContext.vertexSlot].paintSorted(renderingContext);
+ }
+
+ /**
+ * Returns the number of shapes queued for rendering.
+ *
+ * @return the shape count
+ */
+ public int getQueuedShapeCount() {
+ return aggregators[0].size();
+ }
+
+ /**
+ * Returns the live list of shapes queued in the aggregator.
+ * Package-private: exposed for pipeline verification tests.
+ *
+ * @return the queued shapes
+ */
+ List<AbstractCoordinateShape> getQueuedShapes() {
+ return aggregators[0].getQueuedShapes();
+ }
+
+ /**
+ * Returns the number of shapes in each paint-segment bin, or null when
+ * no binning is active. Package-private: exposed for pipeline
+ * verification tests.
+ *
+ * @return per-segment bin sizes, or null
+ */
+ int[] getBinSizes() {
+ return aggregators[0].getBinSizes();
+ }
+
+ /**
+ * Returns the root composite shape containing all scene shapes.
+ *
+ * <p>Useful for headless setups that must transform the scene without
+ * going through the full collection pipeline (e.g. pre-building render
+ * lists before a GI snapshot reads them via
+ * {@link #collectRenderTriangles}).</p>
+ *
+ * @return the root composite (never null)
+ */
+ public AbstractCompositeShape getRootComposite() {
+ return rootComposite;
+ }
+
+ /**
+ * Sets the cache rebuild flag on the root composite.
+ *
+ * <p>Used internally to force a render-list rebuild. Public for advanced use cases.</p>
+ *
+ * @param needsRebuild {@code true} to force cache rebuild
+ */
+ public void setCacheNeedsRebuild(final boolean needsRebuild) {
+ rootComposite.setCacheNeedsRebuild(needsRebuild);
+ }
+}
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster;
+
+/**
+ * Identifies which eye is being rendered in stereoscopic mode.
+ *
+ * @see RenderingContext#stereoEye
+ */
+public enum StereoEye {
+ /** Normal single-view rendering (no stereo). */
+ NONE,
+ /** Left eye view in side-by-side stereo mode. */
+ LEFT,
+ /** Right eye view in side-by-side stereo mode. */
+ RIGHT
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster;
+import eu.svjatoslav.aukio.e3d.math.TransformStack;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point2D;
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+
+/**
+ * A vertex in 3D space with transformation and screen projection support.
+ *
+ * <p>A vertex represents a corner point of a polygon or polyhedron. In addition to
+ * the 3D coordinate, it stores the transformed position (relative to viewer) and
+ * the projected screen coordinates for rendering.</p>
+ *
+ * <p><b>Coordinate spaces:</b></p>
+ * <ul>
+ * <li>{@link #coordinate} - Original position in local/model space</li>
+ * <li>{@link #transformedCoordinate} - Position relative to viewer (camera space)</li>
+ * <li>{@link #onScreenCoordinate} - 2D screen position after perspective projection</li>
+ * </ul>
+ *
+ * <p><b>Example:</b></p>
+ * <pre>{@code
+ * Vertex v = new Vertex(new Point3D(10, 20, 30));
+ * v.calculateLocationRelativeToViewer(transformStack, renderContext);
+ * if (v.transformedCoordinate.z > 0) {
+ * // Vertex is in front of the camera
+ * }
+ * }</pre>
+ *
+ * @see Point3D
+ * @see TransformStack
+ */
+public class Vertex {
+
+ /**
+ * Vertex coordinate in local/model 3D space.
+ */
+ public Point3D coordinate;
+
+ /**
+ * Vertex coordinate relative to the viewer after transformation (camera
+ * space), per buffer slot. Slot parity lets the transform phase of the
+ * NEXT frame write slot B while the paint phase of the current frame
+ * still reads slot A (double-buffered pipeline). Never access directly:
+ * use {@link #transformedCoordinate(RenderingContext)}.
+ */
+ private final Point3D transformedCoordinate0 = new Point3D();
+ private final Point3D transformedCoordinate1 = new Point3D();
+ private final Point3D transformedCoordinate2 = new Point3D();
+
+ /**
+ * Vertex position on screen in pixels, per buffer slot.
+ * Use {@link #onScreenCoordinate(RenderingContext)}.
+ */
+ private final Point2D onScreenCoordinate0 = new Point2D();
+ private final Point2D onScreenCoordinate1 = new Point2D();
+ private final Point2D onScreenCoordinate2 = new Point2D();
+
+ /**
+ * Texture coordinate for UV mapping (optional).
+ */
+ public Point2D textureCoordinate;
+
+ /**
+ * Normal vector for this vertex (optional).
+ * Used by CSG operations for smooth interpolation during polygon splitting.
+ * Null for non-CSG usage; existing rendering code ignores this field.
+ */
+ public Point3D normal;
+
+
+ /**
+ * The transform cycle when each slot was last transformed (for
+ * caching). Keyed by {@link RenderingContext#transformCycleId}, NOT
+ * by frameNumber: in stereo mode both eye passes share the same
+ * parity context and therefore the same frameNumber, while using
+ * different slots — a frameNumber-based key lets one eye's pass
+ * falsely hit the cache entry the other eye wrote for the same slot
+ * an odd number of passes earlier, leaving opposite-eye (wrong
+ * viewport-offset) screen coordinates in the slot: the affected eye
+ * paints fully off-viewport, i.e. a black half-frame (observed as
+ * violent left/right flashing, 2026-09-09). transformCycleId is
+ * unique per pass, so a hit always means "already transformed within
+ * THIS pass" — the only correct dedupe semantics.
+ */
+ private long lastTransformCycle0 = -1;
+ private long lastTransformCycle1 = -1;
+ private long lastTransformCycle2 = -1;
+
+ /**
+ * Creates a vertex at the origin (0, 0, 0) with no texture coordinate.
+ */
+ public Vertex() {
+ this(new Point3D());
+ }
+
+ /**
+ * Creates a vertex at the specified position with no texture coordinate.
+ *
+ * @param coordinate the 3D position of this vertex
+ */
+ public Vertex(final Point3D coordinate) {
+ this(coordinate, null);
+ }
+
+ /**
+ * Creates a vertex at the specified position with an optional texture coordinate.
+ *
+ * @param coordinate the 3D position of this vertex
+ * @param textureCoordinate the UV texture coordinate, or {@code null} for none
+ */
+ public Vertex(final Point3D coordinate, final Point2D textureCoordinate) {
+ this.coordinate = coordinate;
+ this.textureCoordinate = textureCoordinate;
+ }
+
+ /**
+ * Returns the camera-space coordinate for the rendering context's buffer
+ * slot. Valid only after this vertex was transformed for that slot's
+ * current frame.
+ *
+ * @param renderContext the rendering context (selects the buffer slot)
+ * @return the transformed coordinate (camera space) for the active slot
+ */
+ public Point3D transformedCoordinate(final RenderingContext renderContext) {
+ // Dual fields, not a slot array: measured 2026-09-05 (400-sphere
+ // scene) that array indexing adds a second dependent load per access
+ // and cost ~60% of transform phase time; a perfectly-predicted
+ // branch + direct field load is free.
+ final int slot = renderContext.vertexSlot;
+ return slot == 0 ? transformedCoordinate0
+ : slot == 1 ? transformedCoordinate1 : transformedCoordinate2;
+ }
+
+ /**
+ * Returns the screen-space position for the rendering context's buffer
+ * slot.
+ *
+ * @param renderContext the rendering context (selects the buffer slot)
+ * @return the on-screen coordinate (pixels) for the active slot
+ */
+ public Point2D onScreenCoordinate(final RenderingContext renderContext) {
+ final int slot = renderContext.vertexSlot;
+ return slot == 0 ? onScreenCoordinate0
+ : slot == 1 ? onScreenCoordinate1 : onScreenCoordinate2;
+ }
+
+
+ /**
+ * Transforms this vertex from model space to screen space.
+ *
+ * <p>This method applies the transform stack to compute the vertex position
+ * relative to the viewer, then projects it to 2D screen coordinates.
+ * Results are cached per-frame per-slot to avoid redundant calculations.</p>
+ *
+ * @param transforms the transform stack to apply (world-to-camera transforms)
+ * @param renderContext the rendering context providing projection parameters
+ */
+ public void calculateLocationRelativeToViewer(final TransformStack transforms,
+ final RenderingContext renderContext) {
+
+ final Point3D transformedCoordinate;
+ final Point2D onScreenCoordinate;
+ switch (renderContext.vertexSlot) {
+ case 0:
+ if (lastTransformCycle0 == renderContext.transformCycleId)
+ return;
+ lastTransformCycle0 = renderContext.transformCycleId;
+ transformedCoordinate = transformedCoordinate0;
+ onScreenCoordinate = onScreenCoordinate0;
+ break;
+ case 1:
+ if (lastTransformCycle1 == renderContext.transformCycleId)
+ return;
+ lastTransformCycle1 = renderContext.transformCycleId;
+ transformedCoordinate = transformedCoordinate1;
+ onScreenCoordinate = onScreenCoordinate1;
+ break;
+ default:
+ if (lastTransformCycle2 == renderContext.transformCycleId)
+ return;
+ lastTransformCycle2 = renderContext.transformCycleId;
+ transformedCoordinate = transformedCoordinate2;
+ onScreenCoordinate = onScreenCoordinate2;
+ break;
+ }
+ transforms.transform(coordinate, transformedCoordinate);
+ onScreenCoordinate.x = ((transformedCoordinate.x / transformedCoordinate.z) * renderContext.projectionScale);
+ onScreenCoordinate.y = ((transformedCoordinate.y / transformedCoordinate.z) * renderContext.projectionScale);
+ onScreenCoordinate.add(renderContext.centerCoordinate);
+ onScreenCoordinate.x += renderContext.stereoViewportOffsetX;
+ }
+
+ /**
+ * Writes a camera-space position directly into this vertex's slot state
+ * and projects it to screen coordinates, bypassing the transform stack.
+ *
+ * <p>Used by near-plane clipping ({@code AbstractCoordinateShape}), which
+ * creates intersection vertices that exist ONLY in camera space — there
+ * is no model-space coordinate to transform. The given z must be > 0
+ * (clip against the near plane guarantees z == nearPlaneDistance).</p>
+ *
+ * @param x camera-space X
+ * @param y camera-space Y
+ * @param z camera-space Z (depth in front of viewer, > 0)
+ * @param renderContext the rendering context (selects the buffer slot and
+ * provides projection parameters)
+ */
+ public void setCameraSpaceCoordinate(final double x, final double y, final double z,
+ final RenderingContext renderContext) {
+ final Point3D transformedCoordinate;
+ final Point2D onScreenCoordinate;
+ switch (renderContext.vertexSlot) {
+ case 0:
+ transformedCoordinate = transformedCoordinate0;
+ onScreenCoordinate = onScreenCoordinate0;
+ break;
+ case 1:
+ transformedCoordinate = transformedCoordinate1;
+ onScreenCoordinate = onScreenCoordinate1;
+ break;
+ default:
+ transformedCoordinate = transformedCoordinate2;
+ onScreenCoordinate = onScreenCoordinate2;
+ break;
+ }
+ transformedCoordinate.x = x;
+ transformedCoordinate.y = y;
+ transformedCoordinate.z = z;
+ onScreenCoordinate.x = ((x / z) * renderContext.projectionScale);
+ onScreenCoordinate.y = ((y / z) * renderContext.projectionScale);
+ onScreenCoordinate.add(renderContext.centerCoordinate);
+ onScreenCoordinate.x += renderContext.stereoViewportOffsetX;
+ }
+
+ // ========== CSG support methods ==========
+
+ /**
+ * Creates a deep copy of this vertex.
+ * Clones the coordinate, normal (if present), and texture coordinate (if present).
+ * The transformedCoordinate and onScreenCoordinate are not cloned (they are computed per-frame).
+ *
+ * @return a new Vertex with cloned data
+ */
+ public Vertex clone() {
+ final Vertex result = new Vertex(new Point3D(coordinate),
+ textureCoordinate != null ? new Point2D(textureCoordinate) : null);
+ if (normal != null) {
+ result.normal = new Point3D(normal);
+ }
+ return result;
+ }
+
+ /**
+ * Flips the orientation of this vertex by negating the normal vector.
+ * Called when the orientation of a polygon is flipped during CSG operations.
+ * If normal is null, this method does nothing.
+ */
+ public void flip() {
+ if (normal != null) {
+ normal = normal.withNegated();
+ }
+ }
+
+ /**
+ * Creates a new vertex between this vertex and another by linearly interpolating
+ * all properties using parameter t.
+ *
+ * <p>Interpolates: position, normal (if present), and texture coordinate (if present).</p>
+ *
+ * @param other the other vertex to interpolate towards
+ * @param t the interpolation parameter (0 = this vertex, 1 = other vertex)
+ * @return a new Vertex representing the interpolated position
+ */
+ public Vertex interpolate(final Vertex other, final double t) {
+ final Vertex result = new Vertex(
+ coordinate.interpolate(other.coordinate, t),
+ (textureCoordinate != null && other.textureCoordinate != null)
+ ? new Point2D(
+ textureCoordinate.x + (other.textureCoordinate.x - textureCoordinate.x) * t,
+ textureCoordinate.y + (other.textureCoordinate.y - textureCoordinate.y) * t)
+ : null
+ );
+ if (normal != null && other.normal != null) {
+ result.normal = normal.interpolate(other.normal, t);
+ }
+ return result;
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.gi;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+import eu.svjatoslav.aukio.e3d.renderer.raster.ShapeCollection;
+import eu.svjatoslav.aukio.e3d.renderer.raster.lighting.GiLightProvider;
+import eu.svjatoslav.aukio.e3d.renderer.raster.lighting.LightSource;
+import eu.svjatoslav.aukio.e3d.renderer.raster.lighting.LightingManager;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.AbstractCoordinateShape;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon.SolidPolygon;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape;
+import eu.svjatoslav.aukio.e3d.renderer.raster.texture.Texture;
+
+import java.util.ArrayList;
+import java.util.IdentityHashMap;
+import java.util.List;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ThreadLocalRandom;
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * Progressive CPU global illumination, running on dedicated low-priority
+ * threads (never on the render ForkJoinPool).
+ *
+ * <p><b>Two sampling resolutions:</b></p>
+ * <ul>
+ * <li><b>Lightmapped triangles</b> ({@link LightmappedShape}, e.g. the
+ * wrapped polygons of a lightmapping-enabled
+ * {@link eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.LightmappedCompositeShape}):
+ * per-texel sampling. Shadows and gradients live INSIDE the polygon
+ * surface; the painted texture is the premultiplied composite
+ * (baseColor x ambient+direct+indirect), regenerated on GI threads
+ * and swapped in double-buffered — painters never see a half-updated
+ * texture.</li>
+ * <li><b>Plain solid polygons</b>: per-polygon sampling; the result feeds
+ * the flat-shading path through {@link GiLightProvider} (shadow tests
+ * + indirect add). Polygons stay single-colored.</li>
+ * </ul>
+ *
+ * <p><b>Estimator:</b> each sample casts one cosine-weighted hemisphere ray
+ * from the surface. At the hit it evaluates direct light with cached shadow
+ * tests (next-event estimation) plus the hit surface's current indirect
+ * estimate, so bounce light propagates deeper over sweeps without an
+ * explicit recursion limit. Two nested exponential moving averages shape
+ * what the user sees: the inner per-sample EMA smooths Monte Carlo noise in
+ * the indirect term, and the outer per-composite-update EMA wraps the
+ * complete sum ambient+direct+indirect with a fixed alpha — lightmaps start
+ * at a uniform medium irradiance and glide to the traced solution (lit
+ * areas brighten, unlit areas sink to darkness), so no black-to-lit flash
+ * or shadow pop is possible. Scene or light changes rebuild the
+ * snapshot and restart convergence. When converged, workers idle at a low
+ * cadence instead of burning CPU.</p>
+ *
+ * <p><b>Render-side cost:</b> zero ray casting. Lightmapped triangles paint
+ * from their current composite texture; the flat-shading path only reads
+ * cached per-polygon values. Frame rate is unaffected by GI quality.</p>
+ *
+ * <p><b>Limitations:</b> diffuse light only; polygon vertices are used in
+ * composite-local space, so scenes combining composites with non-identity
+ * transforms are traced incorrectly.</p>
+ *
+ * <p><b>Usage:</b></p>
+ * <pre>{@code
+ * GlobalIllumination gi = viewPanel.enableGlobalIllumination(); // 2 threads
+ * }</pre>
+ */
+public class GlobalIllumination implements GiLightProvider {
+
+ /**
+ * Diffuse bounce gain: outgoing radiance is albedo/pi times irradiance
+ * (the pi comes from cosine-weighted hemisphere integration). Without it
+ * the indirect feedback loop converges to several times the direct
+ * energy and the scene saturates.
+ */
+ private static final double BOUNCE_GAIN = 1.0 / Math.PI;
+
+ /** Origin offset along the surface normal to avoid self-intersection. */
+ private static final double ORIGIN_EPSILON = 0.5;
+
+ /** Shadow ray segments end this far before the light to avoid grazing hits. */
+ private static final double LIGHT_EPSILON = 1.0;
+
+ /** Minimum sleep between sweeps once the solution has converged. */
+ private static final long IDLE_SLEEP_MS = 250;
+
+ /** Maximum converged-state sleep: edits restart tracing at this latency. */
+ private static final long IDLE_SLEEP_MAX_MS = 2000;
+
+ /** Minimum interval between composite texture updates. */
+ private static final long COMPOSITE_INTERVAL_MS = 500;
+
+ /** Per-light visibility is tracked for at most this many lights. */
+ private static final int MAX_TRACKED_LIGHTS = 16;
+
+ /** Debug statistics with {@code -De3d.gi.debug}. */
+ private static final boolean DEBUG = Boolean.getBoolean("e3d.gi.debug");
+
+ /** Albedo for snapshot entries that carry no flat color (textured triangles). */
+ private static final Color FALLBACK_ALBEDO = new Color(128, 128, 128);
+
+ /**
+ * EMA policy for the inner per-sample indirect blend: "fixed" (default,
+ * 0.15) keeps every ray hit equally intensive forever — fading toward
+ * darkness stays as alive as brightening. "adaptive" decays alpha with
+ * sample count (lower final noise, but late-time adaptation nearly
+ * stops). {@code -De3d.gi.alphaMode}.
+ */
+ private static final String ALPHA_MODE = System.getProperty("e3d.gi.alphaMode", "fixed");
+ /** Adaptive alpha floor: keeps post-change fade alive. */
+ private static final double ALPHA_FLOOR = Double.parseDouble(System.getProperty("e3d.gi.alphaFloor", "0.08"));
+ /** Spatial despeckle of indirect at composite time. */
+ private static final boolean DESPECKLE = Boolean.parseBoolean(System.getProperty("e3d.gi.despeckle", "true"));
+
+ /**
+ * Outer EMA: fraction of the freshly computed total irradiance blended
+ * into the on-screen composite estimate per update. Lower = slower,
+ * calmer fade (and less visible Monte Carlo noise); higher = faster
+ * reaction. At the default 0.2 and 500 ms update cadence the scene
+ * reaches its true lighting in roughly 5 seconds.
+ * {@code -De3d.gi.compositeAlpha}.
+ */
+ private static final double COMPOSITE_ALPHA =
+ Double.parseDouble(System.getProperty("e3d.gi.compositeAlpha", "0.2"));
+
+ /**
+ * Convergence: declared after five consecutive composite updates whose
+ * average per-texel estimate movement falls below this many light
+ * units. With a constant alpha the estimate never freezes completely
+ * (Monte Carlo jitter), so this judges the VISIBLE movement, not the
+ * per-sample deltas. {@code -De3d.gi.calmThreshold}.
+ */
+ private static final double CALM_THRESHOLD =
+ Double.parseDouble(System.getProperty("e3d.gi.calmThreshold", "1.0"));
+
+ private final ShapeCollection shapes;
+ private final LightingManager lightingManager;
+ private final int threadCount;
+
+ private final List<Thread> threads = new ArrayList<>();
+ private volatile boolean running;
+
+ // --- Snapshot (rebuilt on scene/light change; published via volatile) ---
+
+ private volatile Snapshot snapshot;
+
+ /** Per-polygon state for PLAIN solid polygons, read by render threads. */
+ private final ConcurrentHashMap<AbstractCoordinateShape, GiState> states = new ConcurrentHashMap<>();
+
+ private int lastSeenRenderListVersion = -1;
+ private double lastLightSignature = Double.NaN;
+ private final AtomicInteger workIndex = new AtomicInteger();
+ private volatile int calmSweeps;
+ private volatile long lastCompositeUpdate;
+ private final java.util.concurrent.atomic.AtomicBoolean compositeUpdateInFlight =
+ new java.util.concurrent.atomic.AtomicBoolean();
+
+ private static class Snapshot {
+ List<TriangleBvh.Entry> entries;
+ TriangleBvh bvh;
+ List<LightSource> lights;
+ IdentityHashMap<LightSource, Integer> lightIndex;
+ double ambientR, ambientG, ambientB;
+ /** Flattened work list: one item per lightmap texel / plain polygon. */
+ WorkItem[] workItems;
+ /** All lightmaps in the snapshot (for composite updates). */
+ List<Lightmap> lightmaps;
+ }
+
+ /** One unit of GI work: a lightmap texel, or a whole plain polygon. */
+ private static class WorkItem {
+ TriangleBvh.Entry entry;
+ int texel; // -1 = plain polygon
+ }
+
+ /** Progressive per-polygon GI state for plain solid polygons. */
+ private static class GiState {
+ volatile float indirectR, indirectG, indirectB; // irradiance, light units
+ volatile long visibleBits; // per-light: shadow ray says visible
+ volatile long knownBits; // per-light: visibility computed at least once
+ int nextLight; // round-robin cursor (GI threads only)
+ int samples; // adaptive EMA counter (GI threads only)
+ }
+
+ /**
+ * Creates the GI system. Call {@link #start()} to begin tracing.
+ *
+ * @param shapes the scene to trace
+ * @param lightingManager the lights to sample
+ * @param threadCount dedicated worker threads (2 is a good default)
+ */
+ public GlobalIllumination(final ShapeCollection shapes,
+ final LightingManager lightingManager,
+ final int threadCount) {
+ this.shapes = shapes;
+ this.lightingManager = lightingManager;
+ this.threadCount = Math.max(1, threadCount);
+ }
+
+ /** Registers the GI provider and starts the worker threads. */
+ public void start() {
+ if (running)
+ return;
+ running = true;
+ lightingManager.setGiProvider(this);
+ for (int i = 0; i < threadCount; i++) {
+ final Thread thread = new Thread(this::workLoop, "e3d-gi-" + i);
+ thread.setDaemon(true);
+ thread.setPriority(Thread.MIN_PRIORITY);
+ threads.add(thread);
+ thread.start();
+ }
+ }
+
+ /** Stops the worker threads and unregisters the provider. */
+ public void stop() {
+ running = false;
+ lightingManager.setGiProvider(null);
+ for (final Thread thread : threads)
+ thread.interrupt();
+ threads.clear();
+ }
+
+ /**
+ * Returns whether the GI worker threads are running.
+ *
+ * @return {@code true} after {@link #start()} and before {@link #stop()}
+ */
+ public boolean isRunning() {
+ return running;
+ }
+
+ /**
+ * Returns whether the solution has converged (workers idling at a low
+ * duty cycle). Convergence is declared after five consecutive composite
+ * updates whose average per-texel estimate movement is below
+ * {@code e3d.gi.calmThreshold} (default 1.0 light unit).
+ *
+ * @return {@code true} when converged
+ */
+ public boolean isConverged() {
+ return calmSweeps >= 5;
+ }
+
+ /**
+ * Returns the number of work items in the current scene snapshot
+ * (one per lightmap texel plus one per plain polygon), or 0 when no
+ * snapshot has been built yet.
+ *
+ * @return the work item count
+ */
+ public int getWorkItemCount() {
+ final Snapshot snap = snapshot;
+ return snap == null || snap.workItems == null ? 0 : snap.workItems.length;
+ }
+
+ // ------------------------------------------------------------------
+ // GiLightProvider — plain-polygon path, called from parallel
+ // render-pool threads. Must be fast, thread-safe, allocation-free.
+ // ------------------------------------------------------------------
+
+ @Override
+ public boolean isLightVisible(final SolidPolygon polygon, final LightSource light) {
+ final Snapshot snap = snapshot;
+ if (snap == null)
+ return true;
+ final Integer index = snap.lightIndex.get(light);
+ if (index == null || index >= 64)
+ return true;
+ final GiState state = states.get(polygon);
+ if (state == null)
+ return true; // not computed yet: shadows fade in, never pop out
+ final long bit = 1L << index;
+ if ((state.knownBits & bit) == 0)
+ return true;
+ return (state.visibleBits & bit) != 0;
+ }
+
+ @Override
+ public void addIndirectLight(final SolidPolygon polygon, final Color baseColor, final Color result) {
+ final GiState state = states.get(polygon);
+ if (state == null)
+ return;
+ final int r = result.r + (int) (state.indirectR * baseColor.r / 255f);
+ final int g = result.g + (int) (state.indirectG * baseColor.g / 255f);
+ final int b = result.b + (int) (state.indirectB * baseColor.b / 255f);
+ result.set(Math.min(255, r), Math.min(255, g), Math.min(255, b), result.a);
+ }
+
+ // ------------------------------------------------------------------
+ // Worker threads
+ // ------------------------------------------------------------------
+
+ private void workLoop() {
+ final TriangleBvh.Hit hit = new TriangleBvh.Hit();
+ final double[] pos = new double[3];
+ while (running) {
+ try {
+ maybeRebuildSnapshot();
+ final Snapshot snap = snapshot;
+ if (snap == null || snap.workItems.length == 0) {
+ Thread.sleep(100);
+ continue;
+ }
+
+ // One sweep over all work items. Convergence is judged by
+ // composite-estimate movement inside updateComposites()
+ // (per-sample deltas are Monte Carlo noise and, with the
+ // fixed alpha, never settle).
+ final long sweepStart = System.currentTimeMillis();
+ final int size = snap.workItems.length;
+ double deltaSum = 0;
+ for (int i = 0; i < size && running; i++) {
+ final int index = Math.floorMod(workIndex.getAndIncrement(), size);
+ deltaSum += sample(snap, snap.workItems[index], hit, pos);
+ }
+ final double avgDelta = deltaSum / size;
+
+ // Regenerate composite textures at most every
+ // COMPOSITE_INTERVAL_MS; a paint pass is one texture swap
+ // per triangle, invisible to the render threads. Also
+ // advances the convergence counter.
+ final long now = System.currentTimeMillis();
+ if (now - lastCompositeUpdate >= COMPOSITE_INTERVAL_MS) {
+ updateComposites(snap);
+ lastCompositeUpdate = now;
+ }
+
+ if (DEBUG)
+ System.out.println("[GI] sweep done, avgDelta=" + String.format("%.2f", avgDelta)
+ + ", calmSweeps=" + calmSweeps);
+
+ if (isConverged()) {
+ // Converged: cap duty cycle at ~50% of sweep time
+ // (a big scene's sweep takes seconds; a flat 250ms
+ // sleep would barely throttle it). Hard cap keeps
+ // post-edit re-convergence prompt.
+ final long sweepMillis = System.currentTimeMillis() - sweepStart;
+ Thread.sleep(Math.min(IDLE_SLEEP_MAX_MS,
+ Math.max(IDLE_SLEEP_MS, sweepMillis)));
+ }
+ } catch (final InterruptedException e) {
+ return;
+ } catch (final Exception e) {
+ e.printStackTrace();
+ try {
+ Thread.sleep(500);
+ } catch (final InterruptedException ie) {
+ return;
+ }
+ }
+ }
+ }
+
+ /** One progressive sample: one shadow ray + one bounce ray. */
+ private double sample(final Snapshot snap, final WorkItem item,
+ final TriangleBvh.Hit hit, final double[] pos) {
+ final TriangleBvh.Entry entry = item.entry;
+ final Lightmap lightmap = entry.lightmap;
+
+ final double ox, oy, oz, nx, ny, nz;
+ if (lightmap != null) {
+ lightmap.texelWorldPosition(item.texel, pos);
+ nx = lightmap.normalX;
+ ny = lightmap.normalY;
+ nz = lightmap.normalZ;
+ ox = pos[0] + nx * ORIGIN_EPSILON;
+ oy = pos[1] + ny * ORIGIN_EPSILON;
+ oz = pos[2] + nz * ORIGIN_EPSILON;
+ } else {
+ nx = entry.normal[0];
+ ny = entry.normal[1];
+ nz = entry.normal[2];
+ ox = entry.centroidX + nx * ORIGIN_EPSILON;
+ oy = entry.centroidY + ny * ORIGIN_EPSILON;
+ oz = entry.centroidZ + nz * ORIGIN_EPSILON;
+ }
+
+ // 1. Shadow rays. First visit per texel: test ALL lights, so direct
+ // light + hard shadows appear after one sweep instead of trickling
+ // in over lightCount sweeps. Afterwards: one light, round-robin.
+ final int lightCount = snap.lights.size();
+ if (lightCount > 0) {
+ if (lightmap != null) {
+ lightmap.ensureLightCapacity(lightCount);
+ final boolean firstVisit = lightmap.sampleCounts[item.texel] == 0;
+ if (firstVisit) {
+ for (int i = 0; i < lightCount && i < MAX_TRACKED_LIGHTS; i++)
+ lightmap.lightVisibility[item.texel * lightCount + i] =
+ shadowTest(snap, ox, oy, oz, nx, ny, nz, snap.lights.get(i))
+ ? Lightmap.VISIBILITY_VISIBLE : Lightmap.VISIBILITY_OCCLUDED;
+ } else {
+ final int lightIdx = lightmap.nextLight++ % lightCount;
+ lightmap.lightVisibility[item.texel * lightCount + lightIdx] =
+ shadowTest(snap, ox, oy, oz, nx, ny, nz, snap.lights.get(lightIdx))
+ ? Lightmap.VISIBILITY_VISIBLE : Lightmap.VISIBILITY_OCCLUDED;
+ }
+ } else {
+ final GiState state = states.computeIfAbsent(entry.polygon, p -> new GiState());
+ final int lightIdx = state.nextLight++ % lightCount;
+ final boolean visible = shadowTest(snap, ox, oy, oz, nx, ny, nz, snap.lights.get(lightIdx));
+ final long bit = 1L << lightIdx;
+ synchronized (state) {
+ state.visibleBits = visible ? (state.visibleBits | bit) : (state.visibleBits & ~bit);
+ state.knownBits |= bit;
+ }
+ }
+ }
+
+ // 2. Bounce ray: cosine-weighted hemisphere around the normal.
+ final double[] dir = cosineHemisphere(nx, ny, nz, ThreadLocalRandom.current());
+
+ double targetR = 0, targetG = 0, targetB = 0;
+ if (snap.bvh.nearest(ox, oy, oz, dir[0], dir[1], dir[2], hit)) {
+ // Direct irradiance at the hit point (clamped to display range)
+ // plus the hit surface's current indirect estimate.
+ final double[] irr = directIrradiance(snap, hit);
+ final Color hitColor = colorOf(hit.entry);
+ final float hiR, hiG, hiB;
+ if (hit.entry.lightmap != null) {
+ final int hitTexel = hit.entry.lightmap.texelAt(hit.pointX, hit.pointY, hit.pointZ);
+ hiR = hit.entry.lightmap.indirectR[hitTexel];
+ hiG = hit.entry.lightmap.indirectG[hitTexel];
+ hiB = hit.entry.lightmap.indirectB[hitTexel];
+ } else {
+ final GiState hitState = states.get(hit.entry.polygon);
+ hiR = hitState == null ? 0 : hitState.indirectR;
+ hiG = hitState == null ? 0 : hitState.indirectG;
+ hiB = hitState == null ? 0 : hitState.indirectB;
+ }
+ targetR = BOUNCE_GAIN * hitColor.r * (irr[0] + hiR) / 255.0;
+ targetG = BOUNCE_GAIN * hitColor.g * (irr[1] + hiG) / 255.0;
+ targetB = BOUNCE_GAIN * hitColor.b * (irr[2] + hiB) / 255.0;
+ }
+
+ // Inner EMA update. "fixed" mode (default): every ray hit lands
+ // with the same weight forever, so unlit areas keep fading to
+ // darkness at the same rate lit areas brighten. "adaptive" mode:
+ // alpha starts at ~1 and decays with sample count (floored).
+ if (lightmap != null) {
+ final int count = Math.min(32000, ++lightmap.sampleCounts[item.texel]);
+ final float alpha = "fixed".equals(ALPHA_MODE) ? 0.15f
+ : (float) Math.max(ALPHA_FLOOR, 2f / (2f + count));
+ final float dR = (float) (targetR - lightmap.indirectR[item.texel]);
+ final float dG = (float) (targetG - lightmap.indirectG[item.texel]);
+ final float dB = (float) (targetB - lightmap.indirectB[item.texel]);
+ lightmap.indirectR[item.texel] += alpha * dR;
+ lightmap.indirectG[item.texel] += alpha * dG;
+ lightmap.indirectB[item.texel] += alpha * dB;
+ return Math.max(Math.abs(dR), Math.max(Math.abs(dG), Math.abs(dB))) * alpha;
+ } else {
+ final GiState state = states.computeIfAbsent(entry.polygon, p -> new GiState());
+ synchronized (state) {
+ final int count = Math.min(32000, ++state.samples);
+ final float alpha = "fixed".equals(ALPHA_MODE) ? 0.15f
+ : (float) Math.max(ALPHA_FLOOR, 2f / (2f + count));
+ final float dR = (float) (targetR - state.indirectR);
+ final float dG = (float) (targetG - state.indirectG);
+ final float dB = (float) (targetB - state.indirectB);
+ state.indirectR += alpha * dR;
+ state.indirectG += alpha * dG;
+ state.indirectB += alpha * dB;
+ return Math.max(Math.abs(dR), Math.max(Math.abs(dG), Math.abs(dB))) * alpha;
+ }
+ }
+ }
+
+ /** Shadow ray from a surface point toward a light. */
+ private boolean shadowTest(final Snapshot snap,
+ final double ox, final double oy, final double oz,
+ final double nx, final double ny, final double nz,
+ final LightSource light) {
+ final Point3D lightPos = light.getPosition();
+ final double dx = lightPos.x - ox;
+ final double dy = lightPos.y - oy;
+ final double dz = lightPos.z - oz;
+ final double dist = Math.sqrt(dx * dx + dy * dy + dz * dz);
+ if (dist < 1.0)
+ return true;
+
+ // Light behind the surface never illuminates it.
+ if ((dx * nx + dy * ny + dz * nz) / dist <= 0)
+ return false;
+
+ final double maxT = dist - LIGHT_EPSILON;
+ if (maxT <= 0)
+ return true;
+ return !snap.bvh.occluded(ox, oy, oz, dx / dist, dy / dist, dz / dist, maxT);
+ }
+
+ /**
+ * Direct irradiance at a ray hit point, same scale as LightingManager,
+ * clamped to display range: light units near a lamp can sum far beyond
+ * 255 and feeding unbounded energy into the bounce loop saturates the
+ * scene. Uses the hit surface's CACHED visibility (no new shadow rays).
+ */
+ private double[] directIrradiance(final Snapshot snap, final TriangleBvh.Hit hit) {
+ final TriangleBvh.Entry entry = hit.entry;
+ final Lightmap lightmap = entry.lightmap;
+
+ double r = snap.ambientR, g = snap.ambientG, b = snap.ambientB;
+ final int lightCount = snap.lights.size();
+ final int hitTexel = lightmap != null
+ ? lightmap.texelAt(hit.pointX, hit.pointY, hit.pointZ) : -1;
+ final GiState hitState = lightmap == null ? states.get(entry.polygon) : null;
+
+ for (int i = 0; i < lightCount && i < MAX_TRACKED_LIGHTS; i++) {
+ final LightSource light = snap.lights.get(i);
+
+ if (lightmap != null) {
+ if (lightmap.lightVisibility != null
+ && lightmap.lightVisibility[hitTexel * lightCount + i] == Lightmap.VISIBILITY_OCCLUDED)
+ continue;
+ } else if (hitState != null) {
+ final long bit = 1L << i;
+ if ((hitState.knownBits & bit) != 0 && (hitState.visibleBits & bit) == 0)
+ continue;
+ }
+
+ final Point3D lightPos = light.getPosition();
+ final double dx = lightPos.x - hit.pointX;
+ final double dy = lightPos.y - hit.pointY;
+ final double dz = lightPos.z - hit.pointZ;
+ final double dist = Math.sqrt(dx * dx + dy * dy + dz * dz);
+ if (dist < 0.0001)
+ continue;
+ final double dot = (entry.normal[0] * dx + entry.normal[1] * dy + entry.normal[2] * dz) / dist;
+ if (dot <= 0)
+ continue;
+ final double attenuation = 1.0 / (1.0 + 0.0001 * dist * dist);
+ final double intensity = dot * attenuation * light.getIntensity();
+ final Color lightColor = light.getColor();
+ r += lightColor.r * intensity;
+ g += lightColor.g * intensity;
+ b += lightColor.b * intensity;
+ }
+ return new double[]{Math.min(255, r), Math.min(255, g), Math.min(255, b)};
+ }
+
+ /** Surface color of a snapshot entry (albedo source). */
+ private static Color colorOf(final TriangleBvh.Entry entry) {
+ if (entry.lightmap != null)
+ return entry.lightmap.baseColor;
+ if (entry.polygon instanceof SolidPolygon)
+ return ((SolidPolygon) entry.polygon).getColor();
+ // Snapshot triangles are not all SolidPolygons (e.g. textured
+ // triangles from a TextCanvas in a GI scene carry no flat color) —
+ // a neutral gray albedo keeps bounce light plausible instead of
+ // throwing ClassCastException into the worker loop.
+ return FALLBACK_ALBEDO;
+ }
+
+ // ------------------------------------------------------------------
+ // Composite textures: baseColor x (ambient + direct with shadows +
+ // indirect), regenerated into the back buffer and swapped in.
+ // ------------------------------------------------------------------
+
+ private void updateComposites(final Snapshot snap) {
+ // Single flight: both workers finish sweeps concurrently and must
+ // not write the same back buffers simultaneously.
+ if (!compositeUpdateInFlight.compareAndSet(false, true))
+ return;
+ try {
+ final int lightCount = snap.lights.size();
+ final double[] pos = new double[3];
+ double movementSum = 0;
+ long texelTotal = 0;
+ for (final Lightmap lightmap : snap.lightmaps) {
+ lightmap.ensureLightCapacity(lightCount);
+ final int width = lightmap.width;
+ final int height = lightmap.height;
+ final int texelCount = width * height;
+
+ // 1. Total irradiance per valid texel (float, no clamping yet).
+ final float[] irrR = new float[texelCount];
+ final float[] irrG = new float[texelCount];
+ final float[] irrB = new float[texelCount];
+ for (final int texel : lightmap.validTexels) {
+ lightmap.texelWorldPosition(texel, pos);
+ double r = snap.ambientR, g = snap.ambientG, b = snap.ambientB;
+ for (int i = 0; i < lightCount && i < MAX_TRACKED_LIGHTS; i++) {
+ if (lightmap.lightVisibility[texel * lightCount + i] == Lightmap.VISIBILITY_OCCLUDED)
+ continue;
+ final LightSource light = snap.lights.get(i);
+ final Point3D lightPos = light.getPosition();
+ final double dx = lightPos.x - pos[0];
+ final double dy = lightPos.y - pos[1];
+ final double dz = lightPos.z - pos[2];
+ final double dist = Math.sqrt(dx * dx + dy * dy + dz * dz);
+ if (dist < 0.0001)
+ continue;
+ final double dot = (lightmap.normalX * dx + lightmap.normalY * dy
+ + lightmap.normalZ * dz) / dist;
+ if (dot <= 0)
+ continue;
+ final double attenuation = 1.0 / (1.0 + 0.0001 * dist * dist);
+ final double intensity = dot * attenuation * light.getIntensity();
+ final Color lightColor = light.getColor();
+ r += lightColor.r * intensity;
+ g += lightColor.g * intensity;
+ b += lightColor.b * intensity;
+ }
+ // Indirect, lightly blended with valid 4-neighbors:
+ // single-texel Monte Carlo spikes are smoothed without
+ // blurring real gradients (texels are sub-pixel at 4K).
+ final float smoothedR = DESPECKLE ? smoothedIndirect(lightmap.indirectR, lightmap, texel) : lightmap.indirectR[texel];
+ final float smoothedG = DESPECKLE ? smoothedIndirect(lightmap.indirectG, lightmap, texel) : lightmap.indirectG[texel];
+ final float smoothedB = DESPECKLE ? smoothedIndirect(lightmap.indirectB, lightmap, texel) : lightmap.indirectB[texel];
+ irrR[texel] = (float) Math.min(255, r) + smoothedR;
+ irrG[texel] = (float) Math.min(255, g) + smoothedG;
+ irrB[texel] = (float) Math.min(255, b) + smoothedB;
+ }
+
+ // 2. Fill the invalid half (u+v > 1) from nearest valid
+ // neighbors, so bilinear upsampling never reads garbage.
+ final boolean[] filled = new boolean[texelCount];
+ for (final int texel : lightmap.validTexels)
+ filled[texel] = true;
+ boolean progressed = true;
+ while (progressed) {
+ progressed = false;
+ for (int t = 0; t < texelCount; t++) {
+ if (filled[t])
+ continue;
+ final int i = t % width;
+ final int j = t / width;
+ final int left = i > 0 ? t - 1 : -1;
+ final int right = i < width - 1 ? t + 1 : -1;
+ final int up = j > 0 ? t - width : -1;
+ final int down = j < height - 1 ? t + width : -1;
+ final int source = left >= 0 && filled[left] ? left
+ : right >= 0 && filled[right] ? right
+ : up >= 0 && filled[up] ? up
+ : down >= 0 && filled[down] ? down : -1;
+ if (source >= 0) {
+ irrR[t] = irrR[source];
+ irrG[t] = irrG[source];
+ irrB[t] = irrB[source];
+ filled[t] = true;
+ progressed = true;
+ }
+ }
+ }
+
+ // 3. Blend the computed irradiance into the persistent
+ // per-texel estimate (the outer EMA), then write the
+ // composite texture 1:1 from the ESTIMATE — the texture
+ // can only move COMPOSITE_ALPHA of the remaining
+ // distance per update, so direct light, shadows and
+ // indirect all fade in/out gradually.
+ final Texture back = lightmap.backTexture();
+ final int[] pixels = back.primaryBitmap.pixels;
+ for (int j = 0; j < height; j++)
+ for (int i = 0; i < width; i++) {
+ final int t = j * width + i;
+ final float dR = (float) (COMPOSITE_ALPHA * (irrR[t] - lightmap.estimateR[t]));
+ final float dG = (float) (COMPOSITE_ALPHA * (irrG[t] - lightmap.estimateG[t]));
+ final float dB = (float) (COMPOSITE_ALPHA * (irrB[t] - lightmap.estimateB[t]));
+ lightmap.estimateR[t] += dR;
+ lightmap.estimateG[t] += dG;
+ lightmap.estimateB[t] += dB;
+ movementSum += Math.max(Math.abs(dR), Math.max(Math.abs(dG), Math.abs(dB)));
+ texelTotal++;
+ pixels[t] = compositePixel(lightmap,
+ lightmap.estimateR[t], lightmap.estimateG[t], lightmap.estimateB[t]);
+ }
+
+ back.resetResampledBitmapCache();
+ if (lightmap.owner != null) {
+ lightmap.owner.setTexture(back);
+ lightmap.swapBuffers();
+ }
+
+ // Debug: -De3d.gi.dumpLightmaps=/tmp/lm dumps composites as PNGs.
+ if (DUMP_DIR != null)
+ dumpLightmap(lightmap, pixels);
+ }
+
+ // Convergence: average per-texel movement of the on-screen
+ // estimate. With a constant alpha the estimate never fully
+ // freezes (Monte Carlo jitter), so CALM_THRESHOLD judges the
+ // VISIBLE movement; five calm updates in a row -> idle.
+ final double avgMovement = texelTotal > 0 ? movementSum / texelTotal : 0;
+ if (avgMovement < CALM_THRESHOLD)
+ calmSweeps++;
+ else
+ calmSweeps = 0;
+ if (DEBUG)
+ System.out.println("[GI] composite update, avgMovement="
+ + String.format("%.2f", avgMovement));
+ } finally {
+ compositeUpdateInFlight.set(false);
+ }
+ }
+
+ private static final String DUMP_DIR = System.getProperty("e3d.gi.dumpLightmaps");
+ private static int dumpCounter;
+
+ private static void dumpLightmap(final Lightmap lightmap, final int[] pixels) {
+ if (dumpCounter++ % 173 != 0) // spread dumps across lightmaps
+ return;
+ try {
+ final int scale = 8;
+ final int w = lightmap.width;
+ final int h = lightmap.height;
+ final java.awt.image.BufferedImage image = new java.awt.image.BufferedImage(
+ w * scale, h * scale, java.awt.image.BufferedImage.TYPE_INT_RGB);
+ for (int j = 0; j < h * scale; j++)
+ for (int i = 0; i < w * scale; i++)
+ image.setRGB(i, j, pixels[(j / scale) * w + (i / scale)]);
+ final java.io.File dir = new java.io.File(DUMP_DIR);
+ dir.mkdirs();
+ final String name = String.format("%s/lm-%03d-%dx%d-(%.0f,%.0f,%.0f).png", DUMP_DIR,
+ dumpCounter, w, h,
+ lightmap.originX, lightmap.originY, lightmap.originZ);
+ javax.imageio.ImageIO.write(image, "png", new java.io.File(name));
+ } catch (final Exception e) {
+ e.printStackTrace();
+ }
+ }
+
+ /**
+ * Indirect value blended 50/50 with the mean of valid 4-neighbors.
+ * Kills single-texel Monte Carlo spikes (bright speckles in shadows).
+ */
+ private static float smoothedIndirect(final float[] indirect, final Lightmap lightmap, final int texel) {
+ final int width = lightmap.width;
+ final int height = lightmap.height;
+ final int i = texel % width;
+ final int j = texel / width;
+ float sum = 0;
+ int count = 0;
+ if (i > 0 && isValid(lightmap, texel - 1)) { sum += indirect[texel - 1]; count++; }
+ if (i < width - 1 && isValid(lightmap, texel + 1)) { sum += indirect[texel + 1]; count++; }
+ if (j > 0 && isValid(lightmap, texel - width)) { sum += indirect[texel - width]; count++; }
+ if (j < height - 1 && isValid(lightmap, texel + width)) { sum += indirect[texel + width]; count++; }
+ if (count == 0)
+ return indirect[texel];
+ return 0.5f * indirect[texel] + 0.5f * sum / count;
+ }
+
+ private static boolean isValid(final Lightmap lightmap, final int texel) {
+ final double u = ((texel % lightmap.width) + 0.5) / lightmap.width;
+ final double v = ((texel / lightmap.width) + 0.5) / lightmap.height;
+ return u + v <= 1.0;
+ }
+
+ /** Composite texel: baseColor scaled by total irradiance, clamped. */
+ private static int compositePixel(final Lightmap lightmap,
+ final double irrR, final double irrG, final double irrB) {
+ final int r = Math.min(255, (int) (irrR * lightmap.baseColor.r / 255));
+ final int g = Math.min(255, (int) (irrG * lightmap.baseColor.g / 255));
+ final int b = Math.min(255, (int) (irrB * lightmap.baseColor.b / 255));
+ return 0xFF000000 | (r << 16) | (g << 8) | b;
+ }
+
+ // ------------------------------------------------------------------
+ // Snapshot management
+ // ------------------------------------------------------------------
+
+ private void maybeRebuildSnapshot() {
+ final int version = AbstractCompositeShape.getGlobalRenderListVersion();
+ final double lightSignature = lightSignature();
+ if (version == lastSeenRenderListVersion && lightSignature == lastLightSignature)
+ return;
+
+ final List<AbstractCoordinateShape> triangles = new ArrayList<>();
+ shapes.collectRenderTriangles(triangles);
+
+ final Snapshot snap = new Snapshot();
+ snap.entries = new ArrayList<>(triangles.size());
+ snap.lightmaps = new ArrayList<>();
+ for (final AbstractCoordinateShape triangle : triangles) {
+ if (triangle.vertices.size() < 3)
+ continue;
+ final TriangleBvh.Entry entry = buildEntry(triangle);
+ snap.entries.add(entry);
+ if (entry.lightmap != null)
+ snap.lightmaps.add(entry.lightmap);
+ }
+ if (!snap.entries.isEmpty())
+ snap.bvh = new TriangleBvh(snap.entries);
+ snap.lights = new ArrayList<>(lightingManager.getLights());
+ snap.lightIndex = new IdentityHashMap<>();
+ for (int i = 0; i < snap.lights.size(); i++)
+ snap.lightIndex.put(snap.lights.get(i), i);
+ final Color ambient = lightingManager.getAmbientLight();
+ snap.ambientR = ambient.r;
+ snap.ambientG = ambient.g;
+ snap.ambientB = ambient.b;
+
+ // Flattened work list: one item per valid lightmap texel,
+ // one per plain polygon.
+ final List<WorkItem> workItems = new ArrayList<>();
+ for (final TriangleBvh.Entry entry : snap.entries) {
+ if (entry.lightmap != null) {
+ for (final int texel : entry.lightmap.validTexels) {
+ final WorkItem item = new WorkItem();
+ item.entry = entry;
+ item.texel = texel;
+ workItems.add(item);
+ }
+ } else {
+ final WorkItem item = new WorkItem();
+ item.entry = entry;
+ item.texel = -1;
+ workItems.add(item);
+ }
+ }
+ snap.workItems = workItems.toArray(new WorkItem[0]);
+
+ snapshot = snap;
+ states.clear();
+ lastSeenRenderListVersion = version;
+ lastLightSignature = lightSignature;
+ calmSweeps = 0; // scene changed: back to full-speed tracing
+
+ if (DEBUG)
+ System.out.println("[GI] snapshot: " + snap.entries.size() + " triangles, "
+ + snap.workItems.length + " work items, "
+ + snap.lightmaps.size() + " lightmaps, "
+ + snap.lights.size() + " lights");
+ }
+
+ private double lightSignature() {
+ double signature = 0;
+ for (final LightSource light : lightingManager.getLights()) {
+ final Point3D p = light.getPosition();
+ final Color c = light.getColor();
+ signature += p.x + p.y + p.z + c.r + c.g + c.b + light.getIntensity() * 31.0;
+ }
+ return signature;
+ }
+
+ private TriangleBvh.Entry buildEntry(final AbstractCoordinateShape triangle) {
+ final TriangleBvh.Entry entry = new TriangleBvh.Entry(triangle);
+ if (triangle instanceof LightmappedShape)
+ entry.lightmap = ((LightmappedShape) triangle).getLightmap();
+
+ final Point3D a = triangle.vertices.get(0).coordinate;
+ final Point3D b = triangle.vertices.get(1).coordinate;
+ final Point3D c = triangle.vertices.get(2).coordinate;
+ entry.v[0] = (float) a.x; entry.v[1] = (float) a.y; entry.v[2] = (float) a.z;
+ entry.v[3] = (float) b.x; entry.v[4] = (float) b.y; entry.v[5] = (float) b.z;
+ entry.v[6] = (float) c.x; entry.v[7] = (float) c.y; entry.v[8] = (float) c.z;
+ entry.centroidX = (float) ((a.x + b.x + c.x) / 3);
+ entry.centroidY = (float) ((a.y + b.y + c.y) / 3);
+ entry.centroidZ = (float) ((a.z + b.z + c.z) / 3);
+ entry.minX = Math.min(entry.v[0], Math.min(entry.v[3], entry.v[6]));
+ entry.maxX = Math.max(entry.v[0], Math.max(entry.v[3], entry.v[6]));
+ entry.minY = Math.min(entry.v[1], Math.min(entry.v[4], entry.v[7]));
+ entry.maxY = Math.max(entry.v[1], Math.max(entry.v[4], entry.v[7]));
+ entry.minZ = Math.min(entry.v[2], Math.min(entry.v[5], entry.v[8]));
+ entry.maxZ = Math.max(entry.v[2], Math.max(entry.v[5], entry.v[8]));
+ // Normal: right-handed cross(b-a, c-a), matching Plane.computeNormal.
+ final double e1x = b.x - a.x, e1y = b.y - a.y, e1z = b.z - a.z;
+ final double e2x = c.x - a.x, e2y = c.y - a.y, e2z = c.z - a.z;
+ double nx = e1y * e2z - e1z * e2y;
+ double ny = e1z * e2x - e1x * e2z;
+ double nz = e1x * e2y - e1y * e2x;
+ final double len = Math.sqrt(nx * nx + ny * ny + nz * nz);
+ if (len > 0) {
+ nx /= len;
+ ny /= len;
+ nz /= len;
+ }
+ entry.normal = new float[]{(float) nx, (float) ny, (float) nz};
+ return entry;
+ }
+
+ /** Cosine-weighted hemisphere direction around a normal. */
+ private double[] cosineHemisphere(final double nx, final double ny, final double nz,
+ final ThreadLocalRandom random) {
+ final double u = random.nextDouble();
+ final double v = random.nextDouble();
+ final double r = Math.sqrt(u);
+ final double theta = 2 * Math.PI * v;
+ final double x = r * Math.cos(theta);
+ final double y = r * Math.sin(theta);
+ final double z = Math.sqrt(Math.max(0, 1 - u));
+
+ // Orthonormal basis around the normal.
+ final double upX = Math.abs(ny) < 0.9 ? 0 : 1;
+ final double upY = Math.abs(ny) < 0.9 ? 1 : 0;
+ double tx = upY * nz;
+ double ty = -upX * nz;
+ double tz = upX * ny - upY * nx;
+ final double tLen = Math.sqrt(tx * tx + ty * ty + tz * tz);
+ tx /= tLen;
+ ty /= tLen;
+ tz /= tLen;
+ final double bx = ny * tz - nz * ty;
+ final double by = nz * tx - nx * tz;
+ final double bz = nx * ty - ny * tx;
+
+ return new double[]{
+ tx * x + bx * y + nx * z,
+ ty * x + by * y + ny * z,
+ tz * x + bz * y + nz * z
+ };
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.gi;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+import eu.svjatoslav.aukio.e3d.renderer.raster.texture.Texture;
+
+/**
+ * Per-triangle lightmap: a small generated texture whose texels map onto the
+ * triangle surface. The triangle's UVs (in texture pixel units) are
+ * (0,0), (width,0), (0,height), so the valid texel region is the half
+ * where u+v <= 1 in normalized coordinates; the other half is filled
+ * by mirroring to keep mipmaps and edge sampling clean.
+ *
+ * <p>What you trace is what you see: the composite texture the painter
+ * samples IS the lightmap, at native texel resolution. Shadow-edge
+ * smoothness comes from tracing at finer resolution (smaller
+ * unitsPerTexel), never from upsampling.</p>
+ *
+ * <p>The GI system stores per-texel indirect irradiance and per-texel
+ * per-light visibility here, and periodically regenerates the premultiplied
+ * composite texture (baseColor x lighting) into the back buffer, then swaps
+ * it onto the rendered triangle — painters never see a half-updated
+ * texture.</p>
+ *
+ * <p><b>Gradual convergence:</b> what reaches the texture is never the raw
+ * computed irradiance but a persistent per-texel exponential moving average
+ * ({@link #estimateR}/{@link #estimateG}/{@link #estimateB}) over the
+ * complete sum ambient+direct+indirect. The estimate starts at a uniform
+ * medium value ({@link #INITIAL_IRRADIANCE}), so the world is visible from
+ * frame one; lit areas then brighten and unlit areas sink to darkness
+ * gradually — no black-to-lit flash is possible, since the texture can only
+ * move a fixed alpha fraction per composite update.</p>
+ *
+ * <p>Threading: texel state arrays are written by GI worker threads and read
+ * by whoever holds the snapshot; element-wise racy access is benign for
+ * progressive refinement. Texture buffer swaps are volatile/atomic via
+ * {@link LightmappedTriangle#setTexture}.</p>
+ */
+public class Lightmap {
+
+ /** Visibility value: not yet computed. */
+ public static final byte VISIBILITY_UNKNOWN = 0;
+ /** Visibility value: shadow ray reached the light. */
+ public static final byte VISIBILITY_VISIBLE = 1;
+ /** Visibility value: shadow ray was blocked. */
+ public static final byte VISIBILITY_OCCLUDED = 2;
+
+ /** Texture size limits, power of two. */
+ private static final int MIN_SIZE = 4;
+ private static final int MAX_SIZE = 128;
+
+ /**
+ * Uniform irradiance the composite estimate starts at (light units,
+ * display scale 0..255): the world begins medium-lit and visible, then
+ * fades toward the traced solution. {@code -De3d.gi.initialIrradiance}.
+ */
+ public static final double INITIAL_IRRADIANCE =
+ Double.parseDouble(System.getProperty("e3d.gi.initialIrradiance", "128"));
+
+ public final int width;
+ public final int height;
+
+ /** Unlit surface color of the triangle. */
+ public final Color baseColor;
+
+ // World mapping: p(u,v) = origin + e1*u + e2*v.
+ public final double originX, originY, originZ;
+ public final double edge1X, edge1Y, edge1Z;
+ public final double edge2X, edge2Y, edge2Z;
+ /** Unit surface normal. */
+ public final double normalX, normalY, normalZ;
+
+ /** Valid (u+v <= 1) texel indices, for round-robin sampling. */
+ public final int[] validTexels;
+
+ /** Per-texel indirect irradiance (light units, pre-albedo). */
+ public final float[] indirectR;
+ public final float[] indirectG;
+ public final float[] indirectB;
+
+ /**
+ * Per-texel EMA estimate of TOTAL irradiance (ambient + direct +
+ * indirect), the only value ever written to the composite texture.
+ * Initialized to {@link #INITIAL_IRRADIANCE} (uniform medium start);
+ * each composite update blends the freshly computed irradiance in with
+ * a fixed alpha, so both brightening and fading to darkness stay alive
+ * forever and no single-frame jump can occur.
+ */
+ public final float[] estimateR;
+ public final float[] estimateG;
+ public final float[] estimateB;
+
+ /**
+ * Per-texel sample counters. In "adaptive" alpha mode they drive the
+ * decaying EMA weight; in the default "fixed" mode they only mark
+ * first-visit texels (all-lights shadow test on the first sweep).
+ */
+ public final short[] sampleCounts;
+
+ /** Per-texel per-light visibility: texelCount * lightCount bytes. */
+ public byte[] lightVisibility;
+ public int lightCount;
+
+ /** Double-buffered composite textures; the triangle shows one, GI fills the other. */
+ private final Texture[] buffers = new Texture[2];
+ private int shownBuffer;
+
+ /** The triangle currently displaying this lightmap (for texture swaps). */
+ public volatile LightmappedTriangle owner;
+
+ /** Round-robin light cursor for shadow sampling (GI threads only). */
+ public int nextLight;
+
+ /**
+ * Creates a lightmap for a triangle.
+ *
+ * @param a first vertex (UV 0,0)
+ * @param b second vertex (UV 1,0)
+ * @param c third vertex (UV 0,1)
+ * @param baseColor unlit surface color
+ * @param unitsPerTexel world units per lightmap texel (resolution knob)
+ * @param normalX unit normal x
+ * @param normalY unit normal y
+ * @param normalZ unit normal z
+ */
+ public Lightmap(final Point3D a, final Point3D b, final Point3D c,
+ final Color baseColor, final double unitsPerTexel,
+ final double normalX, final double normalY, final double normalZ) {
+ this.baseColor = baseColor;
+ originX = a.x;
+ originY = a.y;
+ originZ = a.z;
+ edge1X = b.x - a.x;
+ edge1Y = b.y - a.y;
+ edge1Z = b.z - a.z;
+ edge2X = c.x - a.x;
+ edge2Y = c.y - a.y;
+ edge2Z = c.z - a.z;
+ this.normalX = normalX;
+ this.normalY = normalY;
+ this.normalZ = normalZ;
+
+ final double len1 = Math.sqrt(edge1X * edge1X + edge1Y * edge1Y + edge1Z * edge1Z);
+ final double len2 = Math.sqrt(edge2X * edge2X + edge2Y * edge2Y + edge2Z * edge2Z);
+ width = powerOfTwo(len1 / unitsPerTexel);
+ height = powerOfTwo(len2 / unitsPerTexel);
+
+ indirectR = new float[width * height];
+ indirectG = new float[width * height];
+ indirectB = new float[width * height];
+ estimateR = new float[width * height];
+ estimateG = new float[width * height];
+ estimateB = new float[width * height];
+ java.util.Arrays.fill(estimateR, (float) INITIAL_IRRADIANCE);
+ java.util.Arrays.fill(estimateG, (float) INITIAL_IRRADIANCE);
+ java.util.Arrays.fill(estimateB, (float) INITIAL_IRRADIANCE);
+ sampleCounts = new short[width * height];
+
+ final int[] valid = new int[width * height];
+ int count = 0;
+ for (int j = 0; j < height; j++)
+ for (int i = 0; i < width; i++) {
+ final double u = (i + 0.5) / width;
+ final double v = (j + 0.5) / height;
+ if (u + v <= 1.0)
+ valid[count++] = j * width + i;
+ }
+ validTexels = new int[count];
+ System.arraycopy(valid, 0, validTexels, 0, count);
+
+ // Both buffers start at the uniform medium INITIAL_IRRADIANCE:
+ // the world is visible from frame one and fades toward the traced
+ // solution (lit areas brighten, unlit areas sink to darkness).
+ buffers[0] = createTexture();
+ buffers[1] = createTexture();
+ }
+
+ private static int powerOfTwo(final double size) {
+ int result = MIN_SIZE;
+ while (result < size && result < MAX_SIZE)
+ result <<= 1;
+ return result;
+ }
+
+ private Texture createTexture() {
+ final Texture texture = new Texture(width, height, 0);
+ final int r = Math.min(255, (int) (INITIAL_IRRADIANCE * baseColor.r / 255));
+ final int g = Math.min(255, (int) (INITIAL_IRRADIANCE * baseColor.g / 255));
+ final int b = Math.min(255, (int) (INITIAL_IRRADIANCE * baseColor.b / 255));
+ final int pixel = 0xFF000000 | (r << 16) | (g << 8) | b;
+ java.util.Arrays.fill(texture.primaryBitmap.pixels, pixel);
+ return texture;
+ }
+
+ /**
+ * World position of a texel center.
+ *
+ * @param texel texel index (j * width + i)
+ * @param out receives x, y, z
+ */
+ public void texelWorldPosition(final int texel, final double[] out) {
+ final double u = ((texel % width) + 0.5) / width;
+ final double v = ((texel / width) + 0.5) / height;
+ out[0] = originX + edge1X * u + edge2X * v;
+ out[1] = originY + edge1Y * u + edge2Y * v;
+ out[2] = originZ + edge1Z * u + edge2Z * v;
+ }
+
+ /**
+ * Texel index nearest to a world point on the triangle plane.
+ *
+ * @param px world x
+ * @param py world y
+ * @param pz world z
+ * @return texel index, clamped into the texture
+ */
+ public int texelAt(final double px, final double py, final double pz) {
+ final double dx = px - originX;
+ final double dy = py - originY;
+ final double dz = pz - originZ;
+ final double d11 = edge1X * edge1X + edge1Y * edge1Y + edge1Z * edge1Z;
+ final double d22 = edge2X * edge2X + edge2Y * edge2Y + edge2Z * edge2Z;
+ final double d12 = edge1X * edge2X + edge1Y * edge2Y + edge1Z * edge2Z;
+ final double dp1 = dx * edge1X + dy * edge1Y + dz * edge1Z;
+ final double dp2 = dx * edge2X + dy * edge2Y + dz * edge2Z;
+ final double denom = d11 * d22 - d12 * d12;
+ if (denom < 1e-12)
+ return 0;
+ final double u = (dp1 * d22 - dp2 * d12) / denom;
+ final double v = (dp2 * d11 - dp1 * d12) / denom;
+ int i = (int) (u * width);
+ int j = (int) (v * height);
+ if (i < 0) i = 0;
+ if (i >= width) i = width - 1;
+ if (j < 0) j = 0;
+ if (j >= height) j = height - 1;
+ return j * width + i;
+ }
+
+ /**
+ * Ensures the per-texel visibility array matches the light count.
+ * Called from GI threads during sampling.
+ *
+ * @param lights number of lights in the snapshot
+ */
+ public void ensureLightCapacity(final int lights) {
+ if (lightVisibility == null || lightCount != lights) {
+ lightVisibility = new byte[width * height * lights];
+ lightCount = lights;
+ }
+ }
+
+ /**
+ * The texture the triangle should show right now.
+ *
+ * @return the front composite texture
+ */
+ public Texture shownTexture() {
+ return buffers[shownBuffer];
+ }
+
+ /**
+ * The texture GI should write the next composite into.
+ *
+ * @return the back composite texture
+ */
+ public Texture backTexture() {
+ return buffers[1 - shownBuffer];
+ }
+
+ /** Flips the buffers after the back texture has been regenerated. */
+ public void swapBuffers() {
+ shownBuffer = 1 - shownBuffer;
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.gi;
+
+/**
+ * A shape carrying a {@link Lightmap}. The global illumination system
+ * detects this interface in its scene snapshot and samples GI per lightmap
+ * texel instead of per polygon.
+ */
+public interface LightmappedShape {
+
+ /**
+ * Returns the lightmap for this shape.
+ *
+ * @return the lightmap
+ */
+ Lightmap getLightmap();
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.gi;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point2D;
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Vertex;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.texturedpolygon.TexturedTriangle;
+
+/**
+ * A textured triangle whose texture is a GI-generated lightmap composite
+ * (baseColor x lighting). UVs are fixed at (0,0), (width,0), (0,height)
+ * (engine UVs are in texture pixel units): the whole triangle is covered by
+ * its own lightmap, valid region u+v <= 1 in normalized coordinates.
+ *
+ * <p>Shading via {@code LightingManager} does not apply — all light (ambient,
+ * direct with shadows, indirect) lives in the composite texture, which the
+ * GI system regenerates and swaps in every few sweeps.</p>
+ */
+public class LightmappedTriangle extends TexturedTriangle implements LightmappedShape {
+
+ private final Lightmap lightmap;
+
+ /**
+ * Creates a lightmapped triangle.
+ *
+ * @param a first vertex (shared coordinate reference is fine)
+ * @param b second vertex
+ * @param c third vertex
+ * @param baseColor unlit surface color
+ * @param unitsPerTexel world units per lightmap texel
+ * @param normalX unit normal x
+ * @param normalY unit normal y
+ * @param normalZ unit normal z
+ */
+ public LightmappedTriangle(final Point3D a, final Point3D b, final Point3D c,
+ final Color baseColor, final double unitsPerTexel,
+ final double normalX, final double normalY, final double normalZ) {
+ super(new Vertex(a, new Point2D(0, 0)),
+ new Vertex(b, new Point2D(1, 0)),
+ new Vertex(c, new Point2D(0, 1)),
+ null);
+ lightmap = new Lightmap(a, b, c, baseColor, unitsPerTexel,
+ normalX, normalY, normalZ);
+ lightmap.owner = this;
+
+ // UVs are in PRIMARY TEXTURE PIXELS in this engine (multiplication
+ // factor scales them into the selected mip level), so the triangle
+ // corners map to the lightmap corners directly.
+ vertices.get(0).textureCoordinate = new Point2D(0, 0);
+ vertices.get(1).textureCoordinate = new Point2D(lightmap.width, 0);
+ vertices.get(2).textureCoordinate = new Point2D(0, lightmap.height);
+ refreshTextureDistance();
+
+ setTexture(lightmap.shownTexture());
+ }
+
+ @Override
+ public Lightmap getLightmap() {
+ return lightmap;
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.gi;
+
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon.SolidPolygon;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.AbstractCoordinateShape;
+
+import java.util.List;
+
+/**
+ * Bounding volume hierarchy over world-space triangles for fast ray queries.
+ * Used by the global illumination system; deliberately separate from the
+ * voxel octree (which serves voxel tracing and stays untouched).
+ *
+ * <p>Build: top-down median split along the longest AABB axis.
+ * Queries: nearest-hit for bounce rays, any-hit with early out for shadow
+ * rays. Intersection is Möller–Trumbore, two-sided (walls are single quads
+ * that must occlude from both sides). Not thread-safe to build, safe to
+ * query concurrently once published via a volatile/atomic reference.</p>
+ */
+public class TriangleBvh {
+
+ /** One ray-traced triangle with cached data. */
+ public static class Entry {
+ public final AbstractCoordinateShape polygon;
+ /** Lightmap when the polygon is a {@link LightmappedShape}, else null. */
+ public Lightmap lightmap;
+ /** Triangle vertices, world space: x0,y0,z0, x1,y1,z1, x2,y2,z2. */
+ public final float[] v = new float[9];
+ public float centroidX, centroidY, centroidZ;
+ public float minX, minY, minZ, maxX, maxY, maxZ;
+ /** Unit surface normal, world space. */
+ public volatile float[] normal;
+
+ public Entry(final AbstractCoordinateShape polygon) {
+ this.polygon = polygon;
+ }
+ }
+
+ /** Nearest-hit query result. */
+ public static class Hit {
+ public Entry entry;
+ public double t;
+ public double pointX, pointY, pointZ;
+ }
+
+ private static class Node {
+ double minX, minY, minZ, maxX, maxY, maxZ;
+ Node left, right;
+ Entry[] entries; // leaf only
+ }
+
+ private static final int LEAF_SIZE = 4;
+ private static final double EPSILON = 0.01;
+
+ private final Node root;
+
+ /**
+ * Builds the tree over the given triangle entries.
+ *
+ * @param entries triangles to index (must not be empty)
+ */
+ public TriangleBvh(final List<Entry> entries) {
+ root = build(entries.toArray(new Entry[0]), 0, entries.size());
+ }
+
+ private Node build(final Entry[] entries, final int from, final int to) {
+ final Node node = new Node();
+ double minX = Double.MAX_VALUE, minY = Double.MAX_VALUE, minZ = Double.MAX_VALUE;
+ double maxX = -Double.MAX_VALUE, maxY = -Double.MAX_VALUE, maxZ = -Double.MAX_VALUE;
+ for (int i = from; i < to; i++) {
+ final Entry e = entries[i];
+ minX = Math.min(minX, e.minX); maxX = Math.max(maxX, e.maxX);
+ minY = Math.min(minY, e.minY); maxY = Math.max(maxY, e.maxY);
+ minZ = Math.min(minZ, e.minZ); maxZ = Math.max(maxZ, e.maxZ);
+ }
+ node.minX = minX; node.minY = minY; node.minZ = minZ;
+ node.maxX = maxX; node.maxY = maxY; node.maxZ = maxZ;
+
+ final int count = to - from;
+ if (count <= LEAF_SIZE) {
+ node.entries = new Entry[count];
+ System.arraycopy(entries, from, node.entries, 0, count);
+ return node;
+ }
+
+ // Split along the longest axis at the median centroid.
+ final double dx = maxX - minX, dy = maxY - minY, dz = maxZ - minZ;
+ final int axis = (dx >= dy && dx >= dz) ? 0 : (dy >= dz ? 1 : 2);
+ java.util.Arrays.sort(entries, from, to, (a, b) -> {
+ final double ca = axis == 0 ? a.centroidX : axis == 1 ? a.centroidY : a.centroidZ;
+ final double cb = axis == 0 ? b.centroidX : axis == 1 ? b.centroidY : b.centroidZ;
+ return Double.compare(ca, cb);
+ });
+ final int mid = from + count / 2;
+ node.left = build(entries, from, mid);
+ node.right = build(entries, mid, to);
+ return node;
+ }
+
+ /**
+ * Finds the nearest triangle hit along the ray, or null.
+ *
+ * @param hit reusable result object, filled on hit
+ * @return true on hit
+ */
+ public boolean nearest(final double ox, final double oy, final double oz,
+ final double dx, final double dy, final double dz,
+ final Hit hit) {
+ hit.t = Double.MAX_VALUE;
+ hit.entry = null;
+ nearestNode(root, ox, oy, oz, dx, dy, dz, hit);
+ if (hit.entry == null)
+ return false;
+ hit.pointX = ox + dx * hit.t;
+ hit.pointY = oy + dy * hit.t;
+ hit.pointZ = oz + dz * hit.t;
+ return true;
+ }
+
+ private void nearestNode(final Node node, final double ox, final double oy, final double oz,
+ final double dx, final double dy, final double dz, final Hit hit) {
+ if (!rayBox(node, ox, oy, oz, dx, dy, dz, hit.t))
+ return;
+
+ if (node.entries != null) {
+ for (final Entry e : node.entries) {
+ final double t = rayTriangle(ox, oy, oz, dx, dy, dz, e.v);
+ if (t > EPSILON && t < hit.t) {
+ hit.t = t;
+ hit.entry = e;
+ }
+ }
+ return;
+ }
+ nearestNode(node.left, ox, oy, oz, dx, dy, dz, hit);
+ nearestNode(node.right, ox, oy, oz, dx, dy, dz, hit);
+ }
+
+ /**
+ * Any-hit shadow query: is the segment from the origin to
+ * {@code maxT} along the direction blocked?
+ *
+ * @return true if any triangle intersects the segment
+ */
+ public boolean occluded(final double ox, final double oy, final double oz,
+ final double dx, final double dy, final double dz,
+ final double maxT) {
+ return occludedNode(root, ox, oy, oz, dx, dy, dz, maxT);
+ }
+
+ private boolean occludedNode(final Node node, final double ox, final double oy, final double oz,
+ final double dx, final double dy, final double dz, final double maxT) {
+ if (!rayBox(node, ox, oy, oz, dx, dy, dz, maxT))
+ return false;
+
+ if (node.entries != null) {
+ for (final Entry e : node.entries) {
+ final double t = rayTriangle(ox, oy, oz, dx, dy, dz, e.v);
+ if (t > EPSILON && t < maxT)
+ return true;
+ }
+ return false;
+ }
+ return occludedNode(node.left, ox, oy, oz, dx, dy, dz, maxT)
+ || occludedNode(node.right, ox, oy, oz, dx, dy, dz, maxT);
+ }
+
+ /** Slab test: does the ray hit the node box before limitT? */
+ private boolean rayBox(final Node node, final double ox, final double oy, final double oz,
+ final double dx, final double dy, final double dz, final double limitT) {
+ double tMin = 0, tMax = limitT;
+
+ double t1 = (node.minX - ox) / dx;
+ double t2 = (node.maxX - ox) / dx;
+ if (Double.isNaN(t1)) t1 = Double.NEGATIVE_INFINITY;
+ if (Double.isNaN(t2)) t2 = Double.POSITIVE_INFINITY;
+ tMin = Math.max(tMin, Math.min(t1, t2));
+ tMax = Math.min(tMax, Math.max(t1, t2));
+
+ t1 = (node.minY - oy) / dy;
+ t2 = (node.maxY - oy) / dy;
+ if (Double.isNaN(t1)) t1 = Double.NEGATIVE_INFINITY;
+ if (Double.isNaN(t2)) t2 = Double.POSITIVE_INFINITY;
+ tMin = Math.max(tMin, Math.min(t1, t2));
+ tMax = Math.min(tMax, Math.max(t1, t2));
+
+ t1 = (node.minZ - oz) / dz;
+ t2 = (node.maxZ - oz) / dz;
+ if (Double.isNaN(t1)) t1 = Double.NEGATIVE_INFINITY;
+ if (Double.isNaN(t2)) t2 = Double.POSITIVE_INFINITY;
+ tMin = Math.max(tMin, Math.min(t1, t2));
+ tMax = Math.min(tMax, Math.max(t1, t2));
+
+ return tMax >= tMin && tMax > EPSILON;
+ }
+
+ /** Möller–Trumbore, two-sided. Returns t or -1. */
+ private double rayTriangle(final double ox, final double oy, final double oz,
+ final double dx, final double dy, final double dz,
+ final float[] v) {
+ final double e1x = v[3] - v[0], e1y = v[4] - v[1], e1z = v[5] - v[2];
+ final double e2x = v[6] - v[0], e2y = v[7] - v[1], e2z = v[8] - v[2];
+
+ final double px = dy * e2z - dz * e2y;
+ final double py = dz * e2x - dx * e2z;
+ final double pz = dx * e2y - dy * e2x;
+
+ final double det = e1x * px + e1y * py + e1z * pz;
+ if (det > -1e-12 && det < 1e-12)
+ return -1;
+
+ final double invDet = 1.0 / det;
+ final double tx = ox - v[0], ty = oy - v[1], tz = oz - v[2];
+ final double u = (tx * px + ty * py + tz * pz) * invDet;
+ if (u < 0 || u > 1)
+ return -1;
+
+ final double qx = ty * e1z - tz * e1y;
+ final double qy = tz * e1x - tx * e1z;
+ final double qz = tx * e1y - ty * e1x;
+ final double vv = (dx * qx + dy * qy + dz * qz) * invDet;
+ if (vv < 0 || u + vv > 1)
+ return -1;
+
+ final double t = (e2x * qx + e2y * qy + e2z * qz) * invDet;
+ return t > 0 ? t : -1;
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+
+/**
+ * Progressive CPU global illumination.
+ *
+ * <p>{@link eu.svjatoslav.aukio.e3d.renderer.raster.gi.GlobalIllumination}
+ * runs Monte Carlo ray casting on dedicated low-priority threads against a
+ * {@link eu.svjatoslav.aukio.e3d.renderer.raster.gi.TriangleBvh} built over
+ * the rendered polygons, and feeds per-polygon direct-light visibility
+ * (shadows) and indirect irradiance (bounced light) into the shading path
+ * through
+ * {@link eu.svjatoslav.aukio.e3d.renderer.raster.lighting.GiLightProvider}.
+ * Rendering itself never casts rays; illumination converges progressively
+ * and adapts to scene changes over time.</p>
+ *
+ * <p>GI is strictly opt-in: enable it with
+ * {@code viewPanel.enableGlobalIllumination()}.</p>
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.gi;
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.lighting;
+
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon.SolidPolygon;
+
+/**
+ * Optional provider of global-illumination data for
+ * {@link LightingManager}. When a provider is installed, the per-polygon
+ * lighting computation additionally:
+ *
+ * <ul>
+ * <li>asks the provider whether each light source is occluded from the
+ * polygon (direct-light shadows), and</li>
+ * <li>adds the provider's indirect (bounced light) contribution.</li>
+ * </ul>
+ *
+ * <p>Implementations are called from parallel render-pool threads: all
+ * methods must be thread-safe, fast and allocation-free. Providers are
+ * expected to answer from progressively updated caches.</p>
+ *
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.gi.GlobalIllumination the progressive CPU global illumination system
+ */
+public interface GiLightProvider {
+
+ /**
+ * Tells whether a light source currently has an unobstructed path to
+ * the polygon. Until the provider has computed the answer, it should
+ * return {@code true} (light visible): shadows then fade in gradually
+ * instead of popping out.
+ *
+ * @param polygon the shaded polygon
+ * @param light the light source being evaluated
+ * @return true if the light reaches the polygon
+ */
+ boolean isLightVisible(SolidPolygon polygon, LightSource light);
+
+ /**
+ * Adds the polygon's indirect (bounced light) contribution to an
+ * already computed direct-lighting color, in place.
+ *
+ * @param polygon the shaded polygon
+ * @param baseColor the polygon's unlit color (for albedo scaling)
+ * @param result the direct-lighted color to augment (modified in place)
+ */
+ void addIndirectLight(SolidPolygon polygon, Color baseColor, Color result);
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.lighting;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+
+/**
+ * Represents a light source in the 3D scene with position, color, and intensity.
+ *
+ * <p>Light sources emit colored light that illuminates polygons based on their
+ * orientation relative to the light. The intensity of illumination follows the
+ * Lambert cosine law - surfaces facing the light receive full intensity, while
+ * surfaces at an angle receive proportionally less light.</p>
+ *
+ * <p><b>Usage example:</b></p>
+ * <pre>{@code
+ * // Create a yellow light source at position (100, -50, 200)
+ * LightSource light = new LightSource(
+ * new Point3D(100, -50, 200),
+ * Color.YELLOW,
+ * 1.5
+ * );
+ *
+ * // Move the light source
+ * light.setPosition(new Point3D(0, 0, 300));
+ *
+ * // Change the light color
+ * light.setColor(new Color(255, 100, 50));
+ *
+ * // Adjust intensity
+ * light.setIntensity(2.0);
+ * }</pre>
+ *
+ * @see LightingManager manages multiple light sources and calculates shading
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon.SolidPolygon
+ */
+public class LightSource {
+
+ /**
+ * Position of the light source in 3D world space.
+ */
+ private Point3D position;
+
+ /**
+ * Color of the light emitted by this source.
+ */
+ private Color color;
+
+ /**
+ * Intensity multiplier for this light source.
+ * Values greater than 1.0 make the light brighter, values less than 1.0 make it dimmer.
+ * High intensity values can cause surfaces to appear white (clamped at 255).
+ */
+ private double intensity;
+
+ /**
+ * Creates a new light source at the specified position with the given color and intensity.
+ *
+ * @param position the position of the light in world space
+ * @param color the color of the light
+ * @param intensity the intensity multiplier (1.0 = normal brightness)
+ */
+ public LightSource(final Point3D position, final Color color, final double intensity) {
+ this.position = position;
+ this.color = color;
+ this.intensity = intensity;
+ }
+
+ /**
+ * Creates a new light source at the specified position with the given color.
+ * Default intensity is 1.0.
+ *
+ * @param position the position of the light in world space
+ * @param color the color of the light
+ */
+ public LightSource(final Point3D position, final Color color) {
+ this(position, color, 1.0);
+ }
+
+ /**
+ * Returns the color of this light source.
+ *
+ * @return the light color
+ */
+ public Color getColor() {
+ return color;
+ }
+
+ /**
+ * Returns the intensity multiplier of this light source.
+ *
+ * @return the intensity multiplier
+ */
+ public double getIntensity() {
+ return intensity;
+ }
+
+ /**
+ * Returns the position of this light source.
+ *
+ * @return the position in world space
+ */
+ public Point3D getPosition() {
+ return position;
+ }
+
+ /**
+ * Sets the color of this light source.
+ *
+ * @param color the new light color
+ */
+ public void setColor(final Color color) {
+ this.color = color;
+ }
+
+ /**
+ * Sets the intensity multiplier of this light source.
+ *
+ * @param intensity the new intensity multiplier (1.0 = normal brightness)
+ */
+ public void setIntensity(final double intensity) {
+ this.intensity = intensity;
+ }
+
+ /**
+ * Sets the position of this light source.
+ *
+ * @param position the new position in world space
+ */
+ public void setPosition(final Point3D position) {
+ this.position = position;
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.lighting;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon.SolidPolygon;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Manages light sources in the scene and calculates lighting for polygons.
+ *
+ * <p>This class implements flat shading using the Lambert cosine law. For each
+ * polygon face, it calculates the surface normal and determines how much light
+ * each source contributes based on the angle between the normal and the light
+ * direction.</p>
+ *
+ * <p>The lighting calculation considers:</p>
+ * <ul>
+ * <li>Distance from polygon center to each light source</li>
+ * <li>Angle between surface normal and light direction</li>
+ * <li>Color and intensity of each light source</li>
+ * </ul>
+ *
+ * <p><b>Usage example:</b></p>
+ * <pre>{@code
+ * LightingManager lighting = new LightingManager();
+ *
+ * // Add light sources
+ * lighting.addLight(new LightSource(new Point3D(100, -50, 200), Color.YELLOW));
+ * lighting.addLight(new LightSource(new Point3D(-100, 50, 200), Color.BLUE));
+ *
+ * // Set ambient light (base illumination)
+ * lighting.setAmbientLight(new Color(30, 30, 30));
+ *
+ * // Calculate shaded color for a polygon (reusing result Color to avoid allocation)
+ * Color result = new Color();
+ * lighting.computeLighting(polygonCenter, surfaceNormal, baseColor, result);
+ * }</pre>
+ *
+ * @see LightSource represents a single light source
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon.SolidPolygon
+ */
+public class LightingManager {
+
+ private final List<LightSource> lights = new ArrayList<>();
+ private Color ambientLight = new Color(10, 10, 10);
+
+ /**
+ * Optional global-illumination provider. When set, the polygon-aware
+ * {@link #computeLighting(SolidPolygon, Point3D, Point3D, Color, Color)}
+ * overload adds shadow tests and indirect light. Null by default:
+ * lighting behaves exactly as before (no occlusion, no indirect).
+ */
+ private volatile GiLightProvider giProvider;
+
+ /**
+ * Creates a new lighting manager with no light sources.
+ */
+ public LightingManager() {
+ }
+
+ /**
+ * Adds a light source to the scene.
+ *
+ * @param light the light source to add
+ */
+ public void addLight(final LightSource light) {
+ lights.add(light);
+ }
+
+ /**
+ * Computes lighting for a polygon and stores the result in an existing Color.
+ *
+ * <p>This method avoids allocation by reusing an existing Color instance.
+ * Safe to call from multiple threads on the same result Color - the computation
+ * is deterministic (same polygon, same lights = same result).</p>
+ *
+ * @param polygonCenter the center point of the polygon in world space
+ * @param normal the surface normal vector (should be normalized)
+ * @param baseColor the original color of the polygon
+ * @param result the Color to receive the shaded result (modified in place)
+ */
+ public void computeLighting(final Point3D polygonCenter,
+ final Point3D normal,
+ final Color baseColor,
+ final Color result) {
+ // Start with ambient light contribution
+ int totalR = ambientLight.r;
+ int totalG = ambientLight.g;
+ int totalB = ambientLight.b;
+
+ // Calculate contribution from each light source
+ for (final LightSource light : lights) {
+ final Point3D lightPos = light.getPosition();
+ final Color lightColor = light.getColor();
+ final double lightIntensity = light.getIntensity();
+
+ // Calculate vector from polygon to light
+ final double lightDirX = lightPos.x - polygonCenter.x;
+ final double lightDirY = lightPos.y - polygonCenter.y;
+ final double lightDirZ = lightPos.z - polygonCenter.z;
+
+ // Normalize the light direction
+ final double lightDist = Math.sqrt(
+ lightDirX * lightDirX +
+ lightDirY * lightDirY +
+ lightDirZ * lightDirZ
+ );
+
+ if (lightDist < 0.0001)
+ continue;
+
+ final double invLightDist = 1.0 / lightDist;
+ final double normLightDirX = lightDirX * invLightDist;
+ final double normLightDirY = lightDirY * invLightDist;
+ final double normLightDirZ = lightDirZ * invLightDist;
+
+ // Calculate dot product (Lambert cosine law)
+ final double dotProduct = normal.x * normLightDirX +
+ normal.y * normLightDirY +
+ normal.z * normLightDirZ;
+
+ // Only add light if surface faces the light
+ if (dotProduct > 0) {
+ // Apply distance attenuation (inverse square law, simplified)
+ final double attenuation = 1.0 / (1.0 + 0.0001 * lightDist * lightDist);
+ final double intensity = dotProduct * attenuation * lightIntensity;
+
+ // Add light color contribution
+ totalR += (int) (lightColor.r * intensity);
+ totalG += (int) (lightColor.g * intensity);
+ totalB += (int) (lightColor.b * intensity);
+ }
+ }
+
+ // Clamp values to valid range and apply to base color
+ final int r = Math.min(255, (totalR * baseColor.r) / 255);
+ final int g = Math.min(255, (totalG * baseColor.g) / 255);
+ final int b = Math.min(255, (totalB * baseColor.b) / 255);
+
+ result.set(r, g, b, baseColor.a);
+ }
+
+ /**
+ * GI-aware lighting computation: identical to
+ * {@link #computeLighting(Point3D, Point3D, Color, Color)} when no
+ * {@link GiLightProvider} is installed. With a provider, lights occluded
+ * from the polygon are skipped (direct shadows) and the provider's
+ * indirect contribution is added on top.
+ *
+ * @param polygon the polygon being shaded (provider key)
+ * @param polygonCenter the center point of the polygon in world space
+ * @param normal the surface normal vector (should be normalized)
+ * @param baseColor the original color of the polygon
+ * @param result the Color to receive the shaded result (modified in place)
+ */
+ public void computeLighting(final SolidPolygon polygon,
+ final Point3D polygonCenter,
+ final Point3D normal,
+ final Color baseColor,
+ final Color result) {
+ final GiLightProvider gi = giProvider;
+ if (gi == null) {
+ computeLighting(polygonCenter, normal, baseColor, result);
+ return;
+ }
+
+ int totalR = ambientLight.r;
+ int totalG = ambientLight.g;
+ int totalB = ambientLight.b;
+
+ for (final LightSource light : lights) {
+ if (!gi.isLightVisible(polygon, light))
+ continue;
+
+ final Point3D lightPos = light.getPosition();
+ final Color lightColor = light.getColor();
+ final double lightIntensity = light.getIntensity();
+
+ final double lightDirX = lightPos.x - polygonCenter.x;
+ final double lightDirY = lightPos.y - polygonCenter.y;
+ final double lightDirZ = lightPos.z - polygonCenter.z;
+
+ final double lightDist = Math.sqrt(
+ lightDirX * lightDirX +
+ lightDirY * lightDirY +
+ lightDirZ * lightDirZ
+ );
+
+ if (lightDist < 0.0001)
+ continue;
+
+ final double invLightDist = 1.0 / lightDist;
+ final double dotProduct = normal.x * lightDirX * invLightDist +
+ normal.y * lightDirY * invLightDist +
+ normal.z * lightDirZ * invLightDist;
+
+ if (dotProduct > 0) {
+ final double attenuation = 1.0 / (1.0 + 0.0001 * lightDist * lightDist);
+ final double intensity = dotProduct * attenuation * lightIntensity;
+
+ totalR += (int) (lightColor.r * intensity);
+ totalG += (int) (lightColor.g * intensity);
+ totalB += (int) (lightColor.b * intensity);
+ }
+ }
+
+ final int r = Math.min(255, (totalR * baseColor.r) / 255);
+ final int g = Math.min(255, (totalG * baseColor.g) / 255);
+ final int b = Math.min(255, (totalB * baseColor.b) / 255);
+
+ result.set(r, g, b, baseColor.a);
+ gi.addIndirectLight(polygon, baseColor, result);
+ }
+
+ /**
+ * Installs (or clears, with null) the global-illumination provider used
+ * by the polygon-aware computeLighting overload.
+ *
+ * @param giProvider the provider, or null to disable GI
+ */
+ public void setGiProvider(final GiLightProvider giProvider) {
+ this.giProvider = giProvider;
+ }
+
+ /**
+ * Returns the installed global-illumination provider, or null.
+ *
+ * @return the GI provider or null
+ */
+ public GiLightProvider getGiProvider() {
+ return giProvider;
+ }
+
+ /**
+ * Returns the ambient light color.
+ *
+ * @return the ambient light color
+ */
+ public Color getAmbientLight() {
+ return ambientLight;
+ }
+
+ /**
+ * Sets the ambient light color for the scene.
+ *
+ * <p>Ambient light provides base illumination that affects all surfaces
+ * equally, regardless of their orientation.</p>
+ *
+ * @param ambientLight the ambient light color
+ */
+ public void setAmbientLight(final Color ambientLight) {
+ this.ambientLight = ambientLight;
+ }
+
+ /**
+ * Returns all light sources in the scene.
+ *
+ * @return list of light sources
+ */
+ public List<LightSource> getLights() {
+ return lights;
+ }
+
+ /**
+ * Removes a light source from the scene.
+ *
+ * @param light the light source to remove
+ */
+ public void removeLight(final LightSource light) {
+ lights.remove(light);
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+
+/**
+ * Lighting system for flat-shaded polygon rendering.
+ *
+ * <p>This package implements a simple Lambertian lighting model for shading
+ * solid polygons based on their surface normals relative to light sources.</p>
+ *
+ * <p>Key classes:</p>
+ * <ul>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.raster.lighting.LightingManager} - Manages lights and calculates shading</li>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.raster.lighting.LightSource} - Represents a point light source</li>
+ * </ul>
+ *
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.lighting.LightingManager
+ */
+
+package eu.svjatoslav.aukio.e3d.renderer.raster.lighting;
\ No newline at end of file
--- /dev/null
+/**
+ * Rasterization-based real-time software renderer for the Aukio 3D engine.
+ *
+ * <p>This package provides a complete rasterization pipeline that renders 3D scenes
+ * to a 2D pixel buffer using traditional approaches:</p>
+ * <ul>
+ * <li><b>Wireframe rendering</b> - lines and wireframe shapes</li>
+ * <li><b>Solid polygon rendering</b> - filled polygons with flat shading</li>
+ * <li><b>Textured polygon rendering</b> - polygons with texture mapping and mipmap support</li>
+ * <li><b>Depth sorting</b> - back-to-front Z-index ordering feeding the two-pass z-buffer paint</li>
+ * </ul>
+ *
+ * <p>Key classes in this package:</p>
+ * <ul>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.raster.ShapeCollection} - root container for all 3D shapes in a scene</li>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.raster.RenderAggregator} - collects and depth-sorts shapes for rendering</li>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.raster.Color} - RGBA color representation with predefined constants</li>
+ * </ul>
+ *
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic basic shape primitives (lines, polygons)
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite composite shapes (boxes, grids, text)
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.texture texture and mipmap support
+ */
+
+package eu.svjatoslav.aukio.e3d.renderer.raster;
+
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes;
+
+import eu.svjatoslav.aukio.e3d.geometry.Box;
+import eu.svjatoslav.aukio.e3d.geometry.Point2D;
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.RenderingContext;
+import eu.svjatoslav.aukio.e3d.math.TransformStack;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Vertex;
+import eu.svjatoslav.aukio.e3d.renderer.raster.RenderAggregator;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * Base class for shapes defined by a list of vertex coordinates.
+ *
+ * <p>This is the foundation for all primitive renderable shapes such as lines,
+ * solid polygons, and textured polygons. Each shape has a list of vertices
+ * ({@link Vertex} objects) that define its geometry in 3D space.</p>
+ *
+ * <p>During each render frame, the {@link #transform} method projects all vertices
+ * from world space to screen space. If all vertices are visible (in front of the camera),
+ * the shape is queued in the {@link RenderAggregator} for depth-sorted painting via
+ * the {@link #paint} method.</p>
+ *
+ * <p><b>Creating a custom coordinate shape:</b></p>
+ * <pre>{@code
+ * public class Triangle extends AbstractCoordinateShape {
+ * private final Color color;
+ *
+ * public Triangle(Point3D p1, Point3D p2, Point3D p3, Color color) {
+ * super(new Vertex(p1), new Vertex(p2), new Vertex(p3));
+ * this.color = color;
+ * }
+ *
+ * public void paint(RenderingContext ctx) {
+ * // Custom painting logic using ctx.graphics and
+ * // vertices.get(i).transformedCoordinate for screen positions
+ * }
+ * }
+ * }</pre>
+ *
+ * @see AbstractShape the parent class for all shapes
+ * @see Vertex wraps a 3D coordinate with its transformed (screen-space) position
+ * @see RenderAggregator collects and depth-sorts shapes before painting
+ */
+public abstract class AbstractCoordinateShape extends AbstractShape {
+
+ /**
+ * Global counter used to assign unique IDs to shapes, ensuring deterministic
+ * rendering order for shapes at the same depth.
+ */
+ private static final AtomicInteger lastShapeId = new AtomicInteger();
+
+ /**
+ * Unique identifier for this shape instance, used as a tiebreaker when
+ * sorting shapes with identical Z-depth values.
+ */
+ public final int shapeId;
+
+ /**
+ * The vertex coordinates that define this shape's geometry.
+ * Each vertex contains both the original world-space coordinate and
+ * a transformed screen-space coordinate computed during {@link #transform}.
+ *
+ * <p>Stored as a mutable list to support CSG operations that modify
+ * polygon vertices in place (splitting, flipping).</p>
+ */
+ public final List<Vertex> vertices;
+
+ /**
+ * Average Z-depth of this shape in screen space after transformation,
+ * per buffer slot. Used by the {@link RenderAggregator} to sort shapes
+ * back-to-front (the queue order the two-pass z-buffer paint consumes).
+ * Access via {@link #getZ(RenderingContext)} / {@link #getZ(int)}.
+ */
+ private double onScreenZ0;
+ private double onScreenZ1;
+ private double onScreenZ2;
+
+ /**
+ * Screen-space Y bounds of this shape after transformation, per buffer
+ * slot, expanded by {@link #getScreenYMargin(RenderingContext)} so they
+ * cover every pixel {@link #paint} can touch. Valid only in frames where
+ * this shape was queued for rendering. Used by {@link RenderAggregator}
+ * to bin shapes per paint tile by overlap.
+ */
+ private double onScreenMinY0;
+ private double onScreenMaxY0;
+ private double onScreenMinY1;
+ private double onScreenMaxY1;
+ private double onScreenMinY2;
+ private double onScreenMaxY2;
+
+ /**
+ * Screen-space X bounds of this shape after transformation, per buffer
+ * slot, expanded by {@link #getScreenXMargin(RenderingContext)}.
+ */
+ private double onScreenMinX0;
+ private double onScreenMaxX0;
+ private double onScreenMinX1;
+ private double onScreenMaxX1;
+ private double onScreenMinX2;
+ private double onScreenMaxX2;
+
+ /**
+ * Writes this shape's screen state for one buffer slot in one call.
+ * Used by bulk transform paths ({@code TriangleMeshBlock}) whose
+ * triangles carry no per-vertex objects: the handle exposes the same
+ * per-slot values an object-backed transform would have written, so
+ * the Z comparator and tile binning keep reading plain fields.
+ *
+ * @param slot buffer slot (0, 1 or 2)
+ * @param z average camera-space Z
+ * @param minY screen-space minimum Y (with paint margins)
+ * @param maxY screen-space maximum Y
+ * @param minX screen-space minimum X (with paint margins)
+ * @param maxX screen-space maximum X
+ */
+ protected final void setSlotScreenState(final int slot, final double z,
+ final double minY, final double maxY,
+ final double minX, final double maxX) {
+ if (slot == 0) {
+ onScreenZ0 = z;
+ onScreenMinY0 = minY;
+ onScreenMaxY0 = maxY;
+ onScreenMinX0 = minX;
+ onScreenMaxX0 = maxX;
+ } else if (slot == 1) {
+ onScreenZ1 = z;
+ onScreenMinY1 = minY;
+ onScreenMaxY1 = maxY;
+ onScreenMinX1 = minX;
+ onScreenMaxX1 = maxX;
+ } else {
+ onScreenZ2 = z;
+ onScreenMinY2 = minY;
+ onScreenMaxY2 = maxY;
+ onScreenMinX2 = minX;
+ onScreenMaxX2 = maxX;
+ }
+ }
+
+ /**
+ * Near-plane-clipped vertex loop for this shape, per buffer slot.
+ * Null when the shape was NOT clipped this frame (all original vertices
+ * in front of the near plane) or when the shape was culled. When set,
+ * {@link #paint} must iterate THIS list instead of {@link #vertices}:
+ * the original vertices contain behind-camera positions whose projected
+ * screen coordinates are garbage (divide by z <= 0 flips signs).
+ *
+ * <p>The list holds a mix of original {@link Vertex} objects (their
+ * per-slot state was filled by the normal transform) and freshly
+ * created intersection vertices (filled via
+ * {@link Vertex#setCameraSpaceCoordinate}). Stored per slot so the
+ * double-buffered pipeline can transform frame N+1 into slot B while
+ * frame N is still painting from slot A.</p>
+ */
+ private List<Vertex> clippedVertices0;
+
+ /**
+ * Cached subpixel-cull verdict (see the size check in
+ * {@link #transform}): while {@link #subpixelCulledEpoch} matches the
+ * context's epoch, transform returns immediately without any setup.
+ */
+ private boolean subpixelCulled;
+ private int subpixelCulledEpoch = -1;
+ private List<Vertex> clippedVertices1;
+ private List<Vertex> clippedVertices2;
+
+ /**
+ * Creates a shape with the specified number of vertices, each initialized
+ * to the origin (0, 0, 0).
+ *
+ * @param vertexCount the number of vertices in this shape
+ */
+ public AbstractCoordinateShape(final int vertexCount) {
+ vertices = new ArrayList<>(vertexCount);
+ for (int i = 0; i < vertexCount; i++) {
+ vertices.add(new Vertex());
+ }
+ shapeId = lastShapeId.getAndIncrement();
+ }
+
+ /**
+ * Creates a shape from the given vertices.
+ *
+ * @param vertices the vertices defining this shape's geometry
+ */
+ public AbstractCoordinateShape(final Vertex... vertices) {
+ this.vertices = new ArrayList<>(Arrays.asList(vertices));
+ shapeId = lastShapeId.getAndIncrement();
+ }
+
+ /**
+ * Creates a shape from a list of vertices.
+ *
+ * @param vertices the list of vertices defining this shape's geometry
+ */
+ public AbstractCoordinateShape(final List<Vertex> vertices) {
+ this.vertices = vertices;
+ shapeId = lastShapeId.getAndIncrement();
+ }
+
+ /**
+ * Returns the average Z-depth of this shape in screen space for the
+ * context's buffer slot.
+ *
+ * @param renderingContext the rendering context (selects the buffer slot)
+ * @return the average Z-depth value, used for depth sorting
+ */
+ public double getZ(final RenderingContext renderingContext) {
+ final int slot = renderingContext.vertexSlot;
+ return slot == 0 ? onScreenZ0 : slot == 1 ? onScreenZ1 : onScreenZ2;
+ }
+
+ /**
+ * Returns the average Z-depth of this shape for an explicit buffer slot.
+ *
+ * @param slot buffer slot (0 or 1)
+ * @return the average Z-depth value, used for depth sorting
+ */
+ public double getZ(final int slot) {
+ return slot == 0 ? onScreenZ0 : slot == 1 ? onScreenZ1 : onScreenZ2;
+ }
+
+ /**
+ * Screen-space minimum Y bound (pixels) for the given buffer slot.
+ *
+ * @param slot buffer slot (0 or 1)
+ * @return minimum Y this shape's paint can touch
+ */
+ public double onScreenMinY(final int slot) {
+ return slot == 0 ? onScreenMinY0 : slot == 1 ? onScreenMinY1 : onScreenMinY2;
+ }
+
+ /**
+ * Screen-space maximum Y bound (pixels) for the given buffer slot.
+ *
+ * @param slot buffer slot (0 or 1)
+ * @return maximum Y this shape's paint can touch
+ */
+ public double onScreenMaxY(final int slot) {
+ return slot == 0 ? onScreenMaxY0 : slot == 1 ? onScreenMaxY1 : onScreenMaxY2;
+ }
+
+ /**
+ * Screen-space minimum X bound (pixels) for the given buffer slot.
+ *
+ * @param slot buffer slot (0 or 1)
+ * @return minimum X this shape's paint can touch
+ */
+ public double onScreenMinX(final int slot) {
+ return slot == 0 ? onScreenMinX0 : slot == 1 ? onScreenMinX1 : onScreenMinX2;
+ }
+
+ /**
+ * Screen-space maximum X bound (pixels) for the given buffer slot.
+ *
+ * @param slot buffer slot (0 or 1)
+ * @return maximum X this shape's paint can touch
+ */
+ public double onScreenMaxX(final int slot) {
+ return slot == 0 ? onScreenMaxX0 : slot == 1 ? onScreenMaxX1 : onScreenMaxX2;
+ }
+
+ /**
+ * Sets the average Z-depth for the given buffer slot.
+ *
+ * @param slot buffer slot (0 or 1)
+ * @param z average Z-depth value
+ */
+ public void setZ(final int slot, final double z) {
+ if (slot == 0)
+ onScreenZ0 = z;
+ else if (slot == 1)
+ onScreenZ1 = z;
+ else
+ onScreenZ2 = z;
+ }
+
+ /**
+ * Returns the axis-aligned bounding box computed from vertex coordinates.
+ *
+ * <p>The bounding box encompasses all vertices in this shape, computed
+ * by finding the minimum and maximum coordinates along each axis.</p>
+ *
+ * <p><b>Caching:</b> The bounding box is cached after first computation.
+ * If vertices change, call {@link #invalidateBounds()} before calling
+ * this method to trigger recomputation.</p>
+ *
+ * @return the axis-aligned bounding box in local coordinates
+ */
+ @Override
+ public Box getBoundingBox() {
+ if (cachedBoundingBox == null && !vertices.isEmpty()) {
+ // Compute bounds from vertex coordinates
+ double minX = Double.MAX_VALUE;
+ double maxX = -Double.MAX_VALUE;
+ double minY = Double.MAX_VALUE;
+ double maxY = -Double.MAX_VALUE;
+ double minZ = Double.MAX_VALUE;
+ double maxZ = -Double.MAX_VALUE;
+
+ for (final Vertex vertex : vertices) {
+ final Point3D coord = vertex.coordinate;
+ minX = Math.min(minX, coord.x);
+ maxX = Math.max(maxX, coord.x);
+ minY = Math.min(minY, coord.y);
+ maxY = Math.max(maxY, coord.y);
+ minZ = Math.min(minZ, coord.z);
+ maxZ = Math.max(maxZ, coord.z);
+ }
+
+ cachedBoundingBox = new Box(
+ new Point3D(minX, minY, minZ),
+ new Point3D(maxX, maxY, maxZ)
+ );
+ }
+ return cachedBoundingBox != null ? cachedBoundingBox : super.getBoundingBox();
+ }
+
+ /**
+ * Translates all vertices by the specified offsets.
+ *
+ * <p>This method moves the entire shape by modifying each vertex's
+ * world-space coordinate. It also invalidates the cached bounding box
+ * so that frustum culling uses the correct bounds after movement.</p>
+ *
+ * <p><b>Usage example:</b></p>
+ * <pre>{@code
+ * // Move shape 10 units up (Y decreases in Aukio 3D's coordinate system)
+ * shape.translate(0, -10, 0);
+ *
+ * // Move shape diagonally
+ * shape.translate(5, 0, 5);
+ * }</pre>
+ *
+ * @param dx offset along the X axis (positive = right)
+ * @param dy offset along the Y axis (positive = down, negative = up)
+ * @param dz offset along the Z axis (positive = away from camera)
+ */
+ public void translate(final double dx, final double dy, final double dz) {
+ for (final Vertex vertex : vertices) {
+ vertex.coordinate.x += dx;
+ vertex.coordinate.y += dy;
+ vertex.coordinate.z += dz;
+ }
+ invalidateBounds();
+ }
+
+ /**
+ * Paints this shape onto the rendering context's pixel buffer.
+ *
+ * <p>This method is called after all shapes have been transformed and sorted
+ * by depth. Implementations should use the transformed screen-space coordinates
+ * from {@link Vertex#transformedCoordinate} to draw pixels.</p>
+ *
+ * @param renderBuffer the rendering context containing the pixel buffer and graphics context
+ */
+ public abstract void paint(RenderingContext renderBuffer);
+
+ /**
+ * Extra screen-space Y distance beyond the vertex bounds that
+ * {@link #paint} can touch. Shapes whose paint output extends past the
+ * vertex positions (thick lines, billboards, text glyphs) must override
+ * this so tile binning does not drop them from tiles they
+ * partially overlap.
+ *
+ * @param renderingContext the rendering context (provides projection
+ * parameters for size computation)
+ * @return the Y margin in screen pixels (0 = vertex bounds are exact)
+ */
+ protected double getScreenYMargin(final RenderingContext renderingContext) {
+ return 0;
+ }
+
+ /**
+ * Extra screen-space X distance beyond the vertex bounds that
+ * {@link #paint} can touch. Same contract as
+ * {@link #getScreenYMargin(RenderingContext)}, for the X axis.
+ *
+ * @param renderingContext the rendering context (provides projection
+ * parameters for size computation)
+ * @return the X margin in screen pixels (0 = vertex bounds are exact)
+ */
+ protected double getScreenXMargin(final RenderingContext renderingContext) {
+ return 0;
+ }
+
+ /**
+ * {@inheritDoc}
+ *
+ * <p>Transforms all vertices to screen space by applying the current transform stack.
+ * If ALL vertices are behind the near plane the shape is culled; if SOME are,
+ * the vertex loop is clipped against the near plane (see
+ * {@link #clipToNearPlane(RenderingContext)}) and the clipped loop — not the
+ * original vertices — is queued for rendering. Computes the average Z-depth
+ * and screen bounds from the active (possibly clipped) vertices and queues
+ * this shape for rendering.</p>
+ */
+ @Override
+ public void transform(final TransformStack transforms,
+ final RenderAggregator aggregator,
+ final RenderingContext renderingContext) {
+
+ // Cached subpixel-cull verdict: skip the entire setup (vertex
+ // transforms, clipping, bounds) while the verdict is fresh. The
+ // epoch advances on significant camera movement, so a culled
+ // shape is re-evaluated whenever it could have grown on screen.
+ if (subpixelCulled
+ && subpixelCulledEpoch == renderingContext.subpixelCullingEpoch)
+ return;
+
+ final int slot = renderingContext.vertexSlot;
+ final double near = renderingContext.nearPlaneDistance;
+ boolean anyBehind = false;
+ boolean allBehind = true;
+
+ // Indexed loops, not enhanced-for: an iterator per shape per
+ // frame was a measurable share of render-time allocation
+ // (~26 MB sampled over 8 frames at the FO4 spawn view).
+ for (int vi = 0; vi < vertices.size(); vi++) {
+ final Vertex geometryPoint = vertices.get(vi);
+ geometryPoint.calculateLocationRelativeToViewer(transforms, renderingContext);
+ if (geometryPoint.transformedCoordinate(renderingContext).z > near)
+ allBehind = false;
+ else
+ anyBehind = true;
+ }
+
+ if (allBehind) {
+ setClippedVertices(slot, null);
+ return;
+ }
+
+ final List<Vertex> active;
+ if (anyBehind) {
+ active = clipToNearPlane(renderingContext);
+ // Degenerate sliver (fewer points than a renderable primitive):
+ // a line needs 2, a polygon needs 3.
+ if (active.size() < Math.min(vertices.size(), 3)) {
+ setClippedVertices(slot, null);
+ return;
+ }
+ setClippedVertices(slot, active);
+ } else {
+ setClippedVertices(slot, null);
+ active = vertices;
+ }
+
+ double accumulatedZ = 0;
+ double minY = Double.POSITIVE_INFINITY;
+ double maxY = Double.NEGATIVE_INFINITY;
+ double minX = Double.POSITIVE_INFINITY;
+ double maxX = Double.NEGATIVE_INFINITY;
+
+ for (int vi = 0; vi < active.size(); vi++) {
+ final Vertex geometryPoint = active.get(vi);
+
+ final Point3D transformed = geometryPoint.transformedCoordinate(renderingContext);
+ final Point2D onScreen = geometryPoint.onScreenCoordinate(renderingContext);
+
+ accumulatedZ += transformed.z;
+
+ if (onScreen.y < minY)
+ minY = onScreen.y;
+ if (onScreen.y > maxY)
+ maxY = onScreen.y;
+ if (onScreen.x < minX)
+ minX = onScreen.x;
+ if (onScreen.x > maxX)
+ maxX = onScreen.x;
+ }
+
+ // Subpixel culling: raw projected span (before paint margins)
+ // below the threshold on both axes means the shape cannot cover
+ // even a fraction of one pixel. Cache the verdict so frames with
+ // a barely-moved camera skip this shape's whole transform setup.
+ final double cullThreshold = renderingContext.subpixelCullingThreshold;
+ if (cullThreshold > 0
+ && maxX - minX < cullThreshold
+ && maxY - minY < cullThreshold) {
+ subpixelCulled = true;
+ subpixelCulledEpoch = renderingContext.subpixelCullingEpoch;
+ return;
+ }
+ subpixelCulled = false;
+
+ final double z = accumulatedZ / active.size();
+ final double marginY = getScreenYMargin(renderingContext);
+ final double loY = minY - marginY;
+ final double hiY = maxY + marginY;
+ final double marginX = getScreenXMargin(renderingContext);
+ final double loX = minX - marginX;
+ final double hiX = maxX + marginX;
+ if (slot == 0) {
+ onScreenZ0 = z;
+ onScreenMinY0 = loY;
+ onScreenMaxY0 = hiY;
+ onScreenMinX0 = loX;
+ onScreenMaxX0 = hiX;
+ } else if (slot == 1) {
+ onScreenZ1 = z;
+ onScreenMinY1 = loY;
+ onScreenMaxY1 = hiY;
+ onScreenMinX1 = loX;
+ onScreenMaxX1 = hiX;
+ } else {
+ onScreenZ2 = z;
+ onScreenMinY2 = loY;
+ onScreenMaxY2 = hiY;
+ onScreenMinX2 = loX;
+ onScreenMaxX2 = hiX;
+ }
+ // Screen-space culling: composite frustum culling skips whole
+ // invisible cells, but a visible cell still queues every one of
+ // its triangles — including those behind the camera or past the
+ // viewport edge. Bounds (with paint margins) are already computed
+ // above, so drop shapes that cannot touch the viewport: on dense
+ // scenes this shrinks the sort/paint queues several-fold. The
+ // test mirrors RenderAggregator tile binning, which uses the same
+ // margined bounds, so nothing paintable is ever dropped.
+ if (hiX < renderingContext.renderMinX
+ || loX >= renderingContext.renderMaxX
+ || hiY < renderingContext.renderMinY
+ || loY >= renderingContext.renderMaxY) {
+ return;
+ }
+ aggregator.queueShapeForRendering(this);
+ }
+
+ /**
+ * Returns the near-plane-clipped vertex loop for the context's buffer
+ * slot, or null if this shape was not clipped (or was culled) this
+ * frame. Paint implementations must use this list when non-null.
+ *
+ * @param renderingContext the rendering context (selects the buffer slot)
+ * @return the clipped vertex loop, or null
+ */
+ public List<Vertex> clippedVertices(final RenderingContext renderingContext) {
+ final int slot = renderingContext.vertexSlot;
+ return slot == 0 ? clippedVertices0
+ : slot == 1 ? clippedVertices1 : clippedVertices2;
+ }
+
+ /**
+ * Stores the clipped vertex loop for the given buffer slot.
+ *
+ * @param slot buffer slot (0, 1 or 2)
+ * @param clipped the clipped loop, or null to clear
+ */
+ private void setClippedVertices(final int slot, final List<Vertex> clipped) {
+ if (slot == 0)
+ clippedVertices0 = clipped;
+ else if (slot == 1)
+ clippedVertices1 = clipped;
+ else
+ clippedVertices2 = clipped;
+ }
+
+ /**
+ * Clips this shape's vertex loop against the near plane
+ * (camera-space z == {@code renderingContext.nearPlaneDistance}),
+ * Sutherland-Hodgman style. Assumes at least one vertex is in front and
+ * at least one is behind (checked by {@link #transform}).
+ *
+ * <p>For every edge crossing the plane a new intersection vertex is
+ * created with linearly interpolated position, UV and normal, and its
+ * per-slot screen position is computed immediately via
+ * {@link Vertex#setCameraSpaceCoordinate}. In-front original vertices
+ * pass through by reference.</p>
+ *
+ * <p>A convex N-gon crossing the plane clips to a single contiguous
+ * loop of 3..N+1 vertices (a triangle can become a quad). Two-vertex
+ * shapes (lines) are clipped as a single open edge, yielding the
+ * in-front endpoint plus the intersection point.</p>
+ *
+ * @param renderingContext the rendering context (provides the near
+ * distance and projection parameters)
+ * @return the clipped vertex loop in original winding order
+ */
+ private List<Vertex> clipToNearPlane(final RenderingContext renderingContext) {
+ final double near = renderingContext.nearPlaneDistance;
+ final int n = vertices.size();
+ // Lines (2 vertices) form one open edge, not a closed loop:
+ // iterating n edges would emit the intersection point twice.
+ final int edgeCount = n == 2 ? 1 : n;
+ final List<Vertex> result = new ArrayList<>(n + 1);
+
+ for (int i = 0; i < edgeCount; i++) {
+ final Vertex current = vertices.get(i);
+ final Vertex next = vertices.get((i + 1) % n);
+ final Point3D c = current.transformedCoordinate(renderingContext);
+ final Point3D p = next.transformedCoordinate(renderingContext);
+ final boolean currentIn = c.z > near;
+ final boolean nextIn = p.z > near;
+
+ if (currentIn)
+ result.add(current);
+
+ if (currentIn != nextIn) {
+ final double t = (near - c.z) / (p.z - c.z);
+ result.add(interpolateAtPlane(current, next, c, p, t, renderingContext));
+ }
+ }
+ return result;
+ }
+
+ /**
+ * Creates the vertex where edge a->b crosses the near plane.
+ * Position, texture coordinate and normal are interpolated with the
+ * same parameter t (linear in 3D, which is exactly what
+ * perspective-correct texturing expects of a point on the edge).
+ */
+ private static Vertex interpolateAtPlane(final Vertex a, final Vertex b,
+ final Point3D ca, final Point3D cb,
+ final double t,
+ final RenderingContext renderingContext) {
+ final double x = ca.x + (cb.x - ca.x) * t;
+ final double y = ca.y + (cb.y - ca.y) * t;
+ final double z = ca.z + (cb.z - ca.z) * t;
+
+ final Point2D uv = (a.textureCoordinate != null && b.textureCoordinate != null)
+ ? new Point2D(
+ a.textureCoordinate.x + (b.textureCoordinate.x - a.textureCoordinate.x) * t,
+ a.textureCoordinate.y + (b.textureCoordinate.y - a.textureCoordinate.y) * t)
+ : null;
+
+ final Vertex clipped = new Vertex(new Point3D(x, y, z), uv);
+ if (a.normal != null && b.normal != null)
+ clipped.normal = a.normal.interpolate(b.normal, t);
+ clipped.setCameraSpaceCoordinate(x, y, z, renderingContext);
+ return clipped;
+ }
+
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes;
+
+import eu.svjatoslav.aukio.e3d.geometry.Box;
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.RenderingContext;
+import eu.svjatoslav.aukio.e3d.gui.humaninput.MouseInteractionController;
+import eu.svjatoslav.aukio.e3d.math.TransformStack;
+import eu.svjatoslav.aukio.e3d.renderer.raster.RenderAggregator;
+
+/**
+ * Base class for all renderable shapes in the Aukio 3D engine.
+ *
+ * <p>Every shape that can be rendered must extend this class and implement the
+ * {@link #transform(TransformStack, RenderAggregator, RenderingContext)} method,
+ * which projects the shape from world space into screen space during each render frame.</p>
+ *
+ * <p>Shapes can optionally have a {@link MouseInteractionController} attached to receive
+ * mouse click and hover events when the user interacts with the shape in the 3D view.</p>
+ *
+ * <p><b>Shape hierarchy overview:</b></p>
+ * <pre>
+ * AbstractShape
+ * +-- AbstractCoordinateShape (shapes with vertex coordinates: lines, polygons)
+ * +-- AbstractCompositeShape (groups of sub-shapes: boxes, grids, text canvases)
+ * </pre>
+ *
+ * @see AbstractCoordinateShape for shapes defined by vertex coordinates
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape for compound shapes
+ * @see MouseInteractionController for handling mouse events on shapes
+ */
+public abstract class AbstractShape {
+
+ /**
+ * Default constructor for abstract shape.
+ */
+ public AbstractShape() {
+ }
+
+ /**
+ * Optional controller that receives mouse interaction events (click, enter, exit)
+ * when the user interacts with this shape in the 3D view.
+ * Set to {@code null} if mouse interaction is not needed.
+ */
+ public MouseInteractionController mouseInteractionController;
+
+ /**
+ * Cached bounding box in local coordinates.
+ * Lazily computed on first call to {@link #getBoundingBox()}.
+ * Subclasses should set this to null when geometry changes to trigger recomputation.
+ */
+ protected Box cachedBoundingBox = null;
+
+ /**
+ * Returns the axis-aligned bounding box for this shape in local coordinates.
+ *
+ * <p>The bounding box is used for frustum culling to determine if the shape
+ * is potentially visible before expensive vertex transformations.</p>
+ *
+ * <p><b>Conservative default:</b> Returns a very large box that ensures
+ * the shape is always considered visible. Subclasses should override to
+ * provide tight bounds computed from their geometry.</p>
+ *
+ * <p><b>Caching:</b> The bounding box is cached after first computation.
+ * If geometry changes, call {@link #invalidateBounds()} to trigger
+ * recomputation on next call.</p>
+ *
+ * @return the axis-aligned bounding box in local coordinates
+ */
+ public Box getBoundingBox() {
+ if (cachedBoundingBox == null) {
+ // Conservative default: very large box (shape always visible)
+ cachedBoundingBox = new Box(
+ new Point3D(-1e10, -1e10, -1e10),
+ new Point3D(1e10, 1e10, 1e10)
+ );
+ }
+ return cachedBoundingBox;
+ }
+
+ /**
+ * Invalidates the cached bounding box, forcing recomputation on next call
+ * to {@link #getBoundingBox()}.
+ *
+ * <p>Call this method whenever the shape's geometry changes to ensure
+ * frustum culling uses up-to-date bounds. This is critical for shapes
+ * that move or deform after creation.</p>
+ *
+ * <p><b>Usage example:</b></p>
+ * <pre>{@code
+ * // After modifying vertex coordinates directly:
+ * vertex.coordinate.translate(0, 10, 0);
+ * shape.invalidateBounds();
+ *
+ * // Or use translate() on AbstractCoordinateShape which handles this automatically
+ * }</pre>
+ */
+ public void invalidateBounds() {
+ cachedBoundingBox = null;
+ }
+
+ /**
+ * Assigns a mouse interaction controller to this shape.
+ *
+ * <p>Example usage:</p>
+ * <pre>{@code
+ * shape.setMouseInteractionController(new MouseInteractionController() {
+ * public boolean mouseClicked(int button) {
+ * System.out.println("Shape clicked!");
+ * return true;
+ * }
+ * public boolean mouseEntered() { return false; }
+ * public boolean mouseExited() { return false; }
+ * });
+ * }</pre>
+ *
+ * @param mouseInteractionController the controller to handle mouse events,
+ * or {@code null} to disable mouse interaction
+ */
+ public void setMouseInteractionController(
+ final MouseInteractionController mouseInteractionController) {
+ this.mouseInteractionController = mouseInteractionController;
+ }
+
+ /**
+ * Transforms this shape from world space to screen space and queues it for rendering.
+ *
+ * <p>This method is called once per frame for each shape in the scene. Implementations
+ * should apply the current transform stack to their vertices, compute screen-space
+ * coordinates, and if the shape is visible, add it to the {@link RenderAggregator}
+ * for depth-sorted painting.</p>
+ *
+ * @param transforms the current stack of transforms (world-to-camera transformations)
+ * @param aggregator collects transformed shapes for depth-sorted rendering
+ * @param renderingContext provides frame dimensions, graphics context, and frame metadata
+ */
+ public abstract void transform(final TransformStack transforms,
+ final RenderAggregator aggregator,
+ final RenderingContext renderingContext);
+
+ /**
+ * Estimated cost of transforming this shape, in arbitrary units where
+ * a leaf primitive counts 1. Composites override this with their total
+ * subtree weight. Used by the parallel transform fork to decide where
+ * splitting pays off.
+ *
+ * @param renderingContext the rendering context (frame identity for caching)
+ * @return transform weight, always at least 1
+ */
+ public int getTransformWeight(final RenderingContext renderingContext) {
+ return 1;
+ }
+
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point2D;
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.RenderingContext;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Vertex;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.AbstractCoordinateShape;
+import eu.svjatoslav.aukio.e3d.renderer.raster.texture.Texture;
+import eu.svjatoslav.aukio.e3d.renderer.raster.texture.TextureBitmap;
+
+/**
+ * A billboard: a texture that always faces the viewer.
+ *
+ * <p>This class implements the "billboard" rendering technique where the texture
+ * remains oriented towards the camera regardless of 3D position. The visible size
+ * is calculated based on distance from viewer (z-coordinate) and scale factor.</p>
+ *
+ * <p><b>Texture mapping algorithm:</b></p>
+ * <ol>
+ * <li>Calculates screen coverage based on perspective</li>
+ * <li>Clips to viewport boundaries</li>
+ * <li>Maps texture pixels to screen pixels using proportional scaling</li>
+ * </ol>
+ *
+ * @see GlowingPoint a billboard with a circular gradient texture
+ * @see Texture
+ */
+public class Billboard extends AbstractCoordinateShape {
+
+ private static final double SCALE_MULTIPLIER = 0.005;
+
+ /**
+ * The texture to display on this billboard.
+ */
+ public final Texture texture;
+
+ /**
+ * Scale factor for the billboard's visible size.
+ * <ul>
+ * <li>0 means infinitely small</li>
+ * <li>1 is recommended to maintain texture sharpness</li>
+ * </ul>
+ */
+ private double scale;
+
+ /**
+ * Creates a billboard at the specified position with the given scale and texture.
+ *
+ * @param point the 3D position of the billboard center
+ * @param scale the scale factor (1.0 is recommended for sharpness)
+ * @param texture the texture to display
+ */
+ public Billboard(final Point3D point, final double scale,
+ final Texture texture) {
+ super(new Vertex(point));
+ this.texture = texture;
+ setScale(scale);
+ }
+
+ /**
+ * The screen-aligned quad extends this far above and below the center
+ * vertex, well beyond the (single-vertex) Y range.
+ */
+ @Override
+ protected double getScreenYMargin(final RenderingContext renderingContext) {
+ return (renderingContext.width * scale * texture.primaryBitmap.height)
+ / vertices.get(0).transformedCoordinate(renderingContext).z;
+ }
+
+ /**
+ * Same story on the X axis: the quad extends half its screen width
+ * to either side of the center vertex.
+ */
+ @Override
+ protected double getScreenXMargin(final RenderingContext renderingContext) {
+ return (renderingContext.width * scale * texture.primaryBitmap.width)
+ / vertices.get(0).transformedCoordinate(renderingContext).z;
+ }
+
+ /**
+ * Renders this billboard to the screen.
+ *
+ * <p>The billboard is rendered as a screen-aligned quad centered on the projected
+ * position. The size is computed based on distance and scale factor.</p>
+ *
+ * <p><b>Performance optimization:</b> Uses fixed-point incremental stepping to avoid
+ * per-pixel division, and inlines alpha blending to avoid method call overhead.
+ * This provides 50-70% better performance than the previous division-based approach.</p>
+ *
+ * @param targetRenderingArea the rendering context containing the pixel buffer
+ */
+ @Override
+ public void paint(final RenderingContext targetRenderingArea) {
+ // Sprites paint only in the alpha pass: they blend, depth-TEST
+ // against the opaque z-buffer (solid geometry occludes them),
+ // and never depth-WRITE. The sprite is screen-aligned, so 1/z
+ // is constant across the quad — one depth value for all pixels.
+ if (targetRenderingArea.depthPass == 1)
+ return;
+
+ // distance from camera/viewer to center of the texture
+ final double z = vertices.get(0).transformedCoordinate(targetRenderingArea).z;
+ final double zw = 1d / z;
+
+ // compute forward oriented texture visible distance from center
+ final double visibleHorizontalDistanceFromCenter = (targetRenderingArea.width
+ * scale * texture.primaryBitmap.width) / z;
+
+ final double visibleVerticalDistanceFromCenter = (targetRenderingArea.width
+ * scale * texture.primaryBitmap.height) / z;
+
+ // compute visible pixel density, and get appropriate bitmap
+ final double scale = (visibleHorizontalDistanceFromCenter * 2)
+ / texture.primaryBitmap.width;
+
+ final TextureBitmap textureBitmap = texture.getMipmapForScale(scale);
+
+ final Point2D onScreenCoordinate = vertices.get(0).onScreenCoordinate(targetRenderingArea);
+
+ // compute Y
+ final int onScreenUncappedYStart = (int) (onScreenCoordinate.y - visibleVerticalDistanceFromCenter);
+ final int onScreenUncappedYEnd = (int) (onScreenCoordinate.y + visibleVerticalDistanceFromCenter);
+ final int onScreenUncappedHeight = onScreenUncappedYEnd - onScreenUncappedYStart;
+
+ int onScreenCappedYStart = onScreenUncappedYStart;
+ int onScreenCappedYEnd = onScreenUncappedYEnd;
+
+ // cap Y to upper screen border
+ if (onScreenCappedYStart < 0)
+ onScreenCappedYStart = 0;
+
+ // cap Y to lower screen border
+ if (onScreenCappedYEnd > targetRenderingArea.height)
+ onScreenCappedYEnd = targetRenderingArea.height;
+
+ // clamp to render Y bounds
+ onScreenCappedYStart = Math.max(onScreenCappedYStart, targetRenderingArea.renderMinY);
+ onScreenCappedYEnd = Math.min(onScreenCappedYEnd, targetRenderingArea.renderMaxY);
+ if (onScreenCappedYStart >= onScreenCappedYEnd)
+ return;
+
+ // compute X
+ final int onScreenUncappedXStart = (int) (onScreenCoordinate.x - visibleHorizontalDistanceFromCenter);
+ final int onScreenUncappedXEnd = (int) (onScreenCoordinate.x + visibleHorizontalDistanceFromCenter);
+ final int onScreenUncappedWidth = onScreenUncappedXEnd - onScreenUncappedXStart;
+
+ // cap X to left viewport border (supports stereo per-eye clipping)
+ int onScreenCappedXStart = onScreenUncappedXStart;
+ if (onScreenCappedXStart < targetRenderingArea.renderMinX)
+ onScreenCappedXStart = targetRenderingArea.renderMinX;
+
+ // cap X to right viewport border (supports stereo per-eye clipping)
+ int onScreenCappedXEnd = onScreenUncappedXEnd;
+ if (onScreenCappedXEnd > targetRenderingArea.renderMaxX)
+ onScreenCappedXEnd = targetRenderingArea.renderMaxX;
+
+ if (onScreenCappedXStart >= onScreenCappedXEnd)
+ return;
+
+ final int[] targetPixels = targetRenderingArea.pixels;
+ final float[] targetDepth = targetRenderingArea.depth;
+ final int[] sourcePixels = textureBitmap.pixels;
+ final int textureWidth = textureBitmap.width;
+ final int textureHeight = textureBitmap.height;
+ final double depthMargin = RenderingContext.DEPTH_MARGIN_DZ * zw * zw;
+ final int targetWidth = targetRenderingArea.width;
+
+ // Fixed-point (16.16) texture stepping values - eliminates per-pixel division
+ // Source X advances by textureWidth / onScreenUncappedWidth per screen pixel
+ final int sourceXStep = (textureWidth << 16) / onScreenUncappedWidth;
+ // Source Y advances by textureHeight / onScreenUncappedHeight per screen scanline
+ final int sourceYStep = (textureHeight << 16) / onScreenUncappedHeight;
+
+ // Initialize source Y position (fixed-point) at the first capped scanline
+ int sourceY = ((onScreenCappedYStart - onScreenUncappedYStart) * sourceYStep);
+
+ for (int y = onScreenCappedYStart; y < onScreenCappedYEnd; y++) {
+
+ // Convert fixed-point Y to integer scanline base address
+ final int sourceYInt = sourceY >> 16;
+ final int scanlineBase = sourceYInt * textureWidth;
+
+ // Initialize source X position (fixed-point) at the first capped pixel
+ int sourceX = ((onScreenCappedXStart - onScreenUncappedXStart) * sourceXStep);
+
+ int targetOffset = (y * targetWidth) + onScreenCappedXStart;
+
+ for (int x = onScreenCappedXStart; x < onScreenCappedXEnd; x++) {
+
+ // depth-test (never write): solids occlude sprites
+ if (zw <= targetDepth[targetOffset] - depthMargin) {
+ sourceX += sourceXStep;
+ targetOffset++;
+ continue;
+ }
+
+ // Convert fixed-point X to integer and compute source address
+ final int sourceAddress = scanlineBase + (sourceX >> 16);
+
+ // Inline alpha blending from TextureBitmap.drawPixel()
+ final int sourcePixel = sourcePixels[sourceAddress];
+ final int srcAlpha = (sourcePixel >> 24) & 0xff;
+
+ if (srcAlpha != 0) {
+ if (srcAlpha == 255) {
+ // Fully opaque - direct copy
+ targetPixels[targetOffset] = sourcePixel;
+ } else {
+ // Semi-transparent - alpha blend
+ final int backgroundAlpha = 255 - srcAlpha;
+
+ final int srcR = ((sourcePixel >> 16) & 0xff) * srcAlpha;
+ final int srcG = ((sourcePixel >> 8) & 0xff) * srcAlpha;
+ final int srcB = (sourcePixel & 0xff) * srcAlpha;
+
+ final int destPixel = targetPixels[targetOffset];
+ final int destR = (destPixel >> 16) & 0xff;
+ final int destG = (destPixel >> 8) & 0xff;
+ final int destB = destPixel & 0xff;
+
+ final int r = ((destR * backgroundAlpha) + srcR) >> 8;
+ final int g = ((destG * backgroundAlpha) + srcG) >> 8;
+ final int b = ((destB * backgroundAlpha) + srcB) >> 8;
+
+ targetPixels[targetOffset] = (r << 16) | (g << 8) | b;
+ }
+ }
+
+ // Advance source X using fixed-point addition (no division!)
+ sourceX += sourceXStep;
+ targetOffset++;
+ }
+
+ // Advance source Y using fixed-point addition (no division!)
+ sourceY += sourceYStep;
+ }
+ }
+
+ /**
+ * Sets the scale factor for this billboard.
+ *
+ * @param scale the scale factor (1.0 is recommended for sharpness)
+ */
+ public void setScale(final double scale) {
+ this.scale = scale * SCALE_MULTIPLIER;
+ }
+
+ /**
+ * Returns the 3D position of this billboard.
+ *
+ * @return the center position in world coordinates
+ */
+ public Point3D getLocation() {
+ return vertices.get(0).coordinate;
+ }
+
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+import eu.svjatoslav.aukio.e3d.renderer.raster.texture.Texture;
+
+import java.util.Collections;
+import java.util.Set;
+import java.util.WeakHashMap;
+
+import static java.lang.Math.pow;
+import static java.lang.Math.sqrt;
+
+/**
+ * A glowing 3D point rendered with a circular gradient texture.
+ *
+ * <p>This class creates and reuses textures for glowing points of the same color.
+ * The texture is a circle with an alpha gradient from center to edge, ensuring
+ * a consistent visual appearance regardless of viewing angle.</p>
+ *
+ * <p><b>Texture sharing:</b> Glowing points of the same color share textures
+ * to reduce memory usage. Textures are garbage collected via WeakHashMap when
+ * no longer referenced.</p>
+ *
+ * @see Billboard the parent class
+ * @see Color
+ */
+public class GlowingPoint extends Billboard {
+
+ private static final int TEXTURE_RESOLUTION_PIXELS = 100;
+
+ /**
+ * Set of all existing glowing points, used for texture sharing.
+ */
+ private static final Set<GlowingPoint> glowingPoints = Collections.newSetFromMap(new WeakHashMap<>());
+ private final Color color;
+
+ /**
+ * Creates a glowing point at the specified position with the given size and color.
+ *
+ * @param point the 3D position of the point
+ * @param pointSize the visible size of the point
+ * @param color the color of the glow
+ */
+ public GlowingPoint(final Point3D point, final double pointSize,
+ final Color color) {
+ super(point, computeScale(pointSize), getTexture(color));
+ this.color = color;
+
+ synchronized (glowingPoints) {
+ glowingPoints.add(this);
+ }
+ }
+
+
+ /**
+ * Computes the scale factor from point size.
+ *
+ * @param pointSize the desired visible size
+ * @return the scale factor for the billboard
+ */
+ private static double computeScale(double pointSize) {
+ return pointSize / ((double) (TEXTURE_RESOLUTION_PIXELS / 50f));
+ }
+
+ /**
+ * Returns a texture for a glowing point of the given color.
+ *
+ * <p>Attempts to reuse an existing texture from another glowing point of the
+ * same color. If none exists, creates a new texture.</p>
+ *
+ * @param color the color of the glow
+ * @return a texture with a circular alpha gradient
+ */
+ private static Texture getTexture(final Color color) {
+ // attempt to reuse texture from existing glowing point of the same color
+ synchronized (glowingPoints) {
+ for (GlowingPoint glowingPoint : glowingPoints)
+ if (color.equals(glowingPoint.color))
+ return glowingPoint.texture;
+ }
+
+ // existing texture not found, creating new one
+ return createTexture(color);
+ }
+
+ /**
+ * Creates a texture for a glowing point of the given color.
+ * The texture is a circle with a gradient from transparent to the given color.
+ */
+ private static Texture createTexture(final Color color) {
+ final Texture texture = new Texture(TEXTURE_RESOLUTION_PIXELS, TEXTURE_RESOLUTION_PIXELS, 1);
+ int halfResolution = TEXTURE_RESOLUTION_PIXELS / 2;
+
+ for (int x = 0; x < TEXTURE_RESOLUTION_PIXELS; x++)
+ for (int y = 0; y < TEXTURE_RESOLUTION_PIXELS; y++) {
+ final int distanceFromCenter = (int) sqrt(pow(halfResolution - x, 2) + pow(halfResolution - y, 2));
+
+ int alpha = 255 - ((270 * distanceFromCenter) / halfResolution);
+ if (alpha < 0)
+ alpha = 0;
+
+ texture.primaryBitmap.pixels[texture.primaryBitmap.getAddress(x, y)] =
+ (alpha << 24) | (color.r << 16) | (color.g << 8) | color.b;
+ }
+
+ return texture;
+ }
+
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.line;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point2D;
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.RenderingContext;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Vertex;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.AbstractCoordinateShape;
+
+import java.util.List;
+
+
+/**
+ * A 3D line segment with perspective-correct width and alpha blending.
+ * <p>
+ * This class represents a line between two 3D points, rendered with a specified
+ * width that adjusts based on perspective (distance from the viewer).
+ * The line is drawn using interpolators to handle edge cases and alpha blending for
+ * transparency effects.
+ * <p>
+ * The rendering algorithm:
+ * 1. For thin lines (below a threshold), draws single-pixel lines with alpha
+ * adjustment based on perspective.
+ * 2. For thicker lines, creates four interpolators to define the line's
+ * rectangular area and fills it scanline by scanline.
+ * <p>
+ * Note: The width is scaled by the LINE_WIDTH_MULTIPLIER and adjusted based on
+ * the distance from the viewer (z-coordinate) to maintain a consistent visual size.
+ */
+public class Line extends AbstractCoordinateShape {
+
+ private static final double MINIMUM_WIDTH_THRESHOLD = 1;
+
+ private static final double LINE_WIDTH_MULTIPLIER = 0.2d;
+
+ /**
+ * Thread-local interpolators for line rendering.
+ * Each rendering thread gets its own array to avoid race conditions.
+ */
+ private static final ThreadLocal<LineInterpolator[]> LINE_INTERPOLATORS =
+ ThreadLocal.withInitial(() -> {
+ final LineInterpolator[] arr = new LineInterpolator[4];
+ for (int i = 0; i < arr.length; i++) {
+ arr[i] = new LineInterpolator();
+ }
+ return arr;
+ });
+
+ /**
+ * width of the line.
+ */
+ public final double width;
+
+ /**
+ * Color of the line.
+ */
+ public Color color;
+
+ /**
+ * Creates a copy of an existing line with cloned coordinates and color.
+ *
+ * @param parentLine the line to copy
+ */
+ public Line(final Line parentLine) {
+ this(parentLine.vertices.get(0).coordinate.clone(),
+ parentLine.vertices.get(1).coordinate.clone(),
+ new Color(parentLine.color), parentLine.width);
+ }
+
+ /**
+ * Creates a line between two points with the specified color and width.
+ *
+ * @param point1 the starting point of the line
+ * @param point2 the ending point of the line
+ * @param color the color of the line
+ * @param width the width of the line in world units
+ */
+ public Line(final Point3D point1, final Point3D point2, final Color color,
+ final double width) {
+
+ super(
+ new Vertex(point1),
+ new Vertex(point2)
+ );
+
+ this.color = color;
+ this.width = width;
+ }
+
+ /**
+ * Draws a thick line as a series of horizontal spans.
+ *
+ * <p>Each pixel is depth-tested against the z-buffer (lines
+ * participate in occlusion: solid geometry hides the parts of a
+ * line that lie behind it), but depth is never written — a line
+ * must not occlude geometry painted after it.</p>
+ *
+ * @param line1 the left edge interpolator
+ * @param line2 the right edge interpolator
+ * @param y the Y coordinate of the scanline
+ * @param renderBuffer the rendering context to draw into
+ * @param p1x X of the line's first projected endpoint
+ * @param p1y Y of the line's first projected endpoint
+ * @param dtDx d(t)/dx of the 2D line parameter (xp / len²)
+ * @param dtDy d(t)/dy of the 2D line parameter (yp / len²)
+ * @param zwP1 1/z at the first endpoint
+ * @param zwDelta (1/z at second endpoint) - zwP1
+ */
+ private void drawHorizontalLine(final LineInterpolator line1,
+ final LineInterpolator line2, final int y,
+ final RenderingContext renderBuffer,
+ final double p1x, final double p1y,
+ final double dtDx, final double dtDy,
+ final double zwP1, final double zwDelta) {
+
+ int x1 = line1.getX(y);
+ int x2 = line2.getX(y);
+
+ double d1 = line1.getD();
+ double d2 = line2.getD();
+
+ if (x1 > x2) {
+ final int tmp = x1;
+ x1 = x2;
+ x2 = tmp;
+
+ final double tmp2 = d1;
+ d1 = d2;
+ d2 = tmp2;
+ }
+
+ final int unclippedWidth = x2 - x1;
+ final double dinc = (d2 - d1) / unclippedWidth;
+
+ // 1/z at the first (leftmost) span pixel: project the pixel onto
+ // the 2D line for its parameter t, then interpolate 1/z linearly
+ // (projectively correct along a projected 3D line). Computed
+ // after the endpoint swap so x1 is genuinely the smaller X.
+ double zw = zwP1 + ((((x1 - p1x) * dtDx) + ((y - p1y) * dtDy)) * zwDelta);
+ final double zwInc = dtDx * zwDelta;
+
+ if (x1 < renderBuffer.renderMinX) {
+ d1 += (dinc * (renderBuffer.renderMinX - x1));
+ zw += zwInc * (renderBuffer.renderMinX - x1);
+ x1 = renderBuffer.renderMinX;
+ }
+
+ // x2 is exclusive (loop paints [x1, x2)): clamp to renderMaxX,
+ // not renderMaxX-1, or the rightmost tile column stays unpainted
+ if (x2 >= renderBuffer.renderMaxX)
+ x2 = renderBuffer.renderMaxX;
+
+ final int drawnWidth = x2 - x1;
+
+ int offset = (y * renderBuffer.width) + x1;
+ final int[] pixels = renderBuffer.pixels;
+ final float[] depth = renderBuffer.depth;
+
+ final int lineAlpha = color.a;
+
+ final int colorR = color.r;
+ final int colorG = color.g;
+ final int colorB = color.b;
+
+ for (int i = 0; i < drawnWidth; i++) {
+
+ final double alphaMultiplier = 1d - Math.abs(d1);
+
+ final int realLineAlpha = (int) (lineAlpha * alphaMultiplier);
+ final int backgroundAlpha = 255 - realLineAlpha;
+
+ // Depth-test like pass-2 translucent geometry: never write.
+ if (zw > depth[offset] - RenderingContext.DEPTH_MARGIN_DZ * zw * zw) {
+ final int dest = pixels[offset];
+ final int destR = (dest >> 16) & 0xff;
+ final int destG = (dest >> 8) & 0xff;
+ final int destB = dest & 0xff;
+
+ final int newR = ((destR * backgroundAlpha) + (colorR * realLineAlpha)) >> 8;
+ final int newG = ((destG * backgroundAlpha) + (colorG * realLineAlpha)) >> 8;
+ final int newB = ((destB * backgroundAlpha) + (colorB * realLineAlpha)) >> 8;
+
+ pixels[offset] = (newR << 16) | (newG << 8) | newB;
+ }
+
+ offset++;
+ d1 += dinc;
+ zw += zwInc;
+ }
+
+ }
+
+ /**
+ * Draws a thin line as single pixels with alpha-adjusted color.
+ * Used for lines that appear thin on screen (below minimum width threshold).
+ *
+ * @param buffer the rendering context to draw into
+ * @param alpha the alpha value for the entire line
+ */
+ private void drawSinglePixelHorizontalLine(final RenderingContext buffer,
+ final int alpha,
+ final Point2D onScreenPoint1,
+ final Point2D onScreenPoint2,
+ final double zwP1,
+ final double zwP2) {
+ int xStart = (int) onScreenPoint1.x;
+ int xEnd = (int) onScreenPoint2.x;
+
+ int lineHeight;
+ int yBase;
+ final double zwA;
+ final double zwB;
+
+ if (xStart > xEnd) {
+ final int tmp = xStart;
+ xStart = xEnd;
+ xEnd = tmp;
+ lineHeight = (int) (onScreenPoint1.y - onScreenPoint2.y);
+ yBase = (int) onScreenPoint2.y;
+ // walk runs from endpoint 2 to endpoint 1
+ zwA = zwP2;
+ zwB = zwP1;
+ } else {
+ yBase = (int) onScreenPoint1.y;
+ lineHeight = (int) (onScreenPoint2.y - onScreenPoint1.y);
+ zwA = zwP1;
+ zwB = zwP2;
+ }
+
+ final int lineWidth = xEnd - xStart;
+ if (lineWidth == 0)
+ return;
+
+ final int[] pixels = buffer.pixels;
+ final float[] depth = buffer.depth;
+ final int backgroundAlpha = 255 - alpha;
+
+ final int redWithAlpha = color.r * alpha;
+ final int greenWithAlpha = color.g * alpha;
+ final int blueWithAlpha = color.b * alpha;
+
+ for (int relativeX = 0; relativeX <= lineWidth; relativeX++) {
+ final int x = xStart + relativeX;
+
+ if ((x >= buffer.renderMinX) && (x < buffer.renderMaxX)) {
+
+ final int y = yBase + ((relativeX * lineHeight) / lineWidth);
+ if ((y >= buffer.renderMinY) && (y < buffer.renderMaxY)) {
+ if ((y >= 0) && (y < buffer.height)) {
+ int offset = (y * buffer.width) + x;
+
+ // depth-test (never write): solids occlude lines
+ final double zw = zwA
+ + (((double) relativeX / lineWidth) * (zwB - zwA));
+ if (zw > depth[offset] - RenderingContext.DEPTH_MARGIN_DZ * zw * zw) {
+ final int dest = pixels[offset];
+ final int destR = (dest >> 16) & 0xff;
+ final int destG = (dest >> 8) & 0xff;
+ final int destB = dest & 0xff;
+
+ final int newR = ((destR * backgroundAlpha) + redWithAlpha) >> 8;
+ final int newG = ((destG * backgroundAlpha) + greenWithAlpha) >> 8;
+ final int newB = ((destB * backgroundAlpha) + blueWithAlpha) >> 8;
+
+ pixels[offset] = (newR << 16) | (newG << 8) | newB;
+ }
+ }
+ }
+ }
+ }
+
+ }
+
+ /**
+ * Draws a thin vertical line as single pixels with alpha-adjusted color.
+ * Used for lines that appear thin on screen and are more vertical than horizontal.
+ *
+ * @param buffer the rendering context to draw into
+ * @param alpha the alpha value for the entire line
+ */
+ private void drawSinglePixelVerticalLine(final RenderingContext buffer,
+ final int alpha,
+ final Point2D onScreenPoint1,
+ final Point2D onScreenPoint2,
+ final double zwP1,
+ final double zwP2) {
+ int yStart = (int) onScreenPoint1.y;
+ int yEnd = (int) onScreenPoint2.y;
+
+ int lineWidth;
+ int xBase;
+ final double zwA;
+ final double zwB;
+
+ if (yStart > yEnd) {
+ final int tmp = yStart;
+ yStart = yEnd;
+ yEnd = tmp;
+ lineWidth = (int) (onScreenPoint1.x - onScreenPoint2.x);
+ xBase = (int) onScreenPoint2.x;
+ // walk runs from endpoint 2 to endpoint 1
+ zwA = zwP2;
+ zwB = zwP1;
+ } else {
+ xBase = (int) onScreenPoint1.x;
+ lineWidth = (int) (onScreenPoint2.x - onScreenPoint1.x);
+ zwA = zwP1;
+ zwB = zwP2;
+ }
+
+ final int lineHeight = yEnd - yStart;
+ if (lineHeight == 0)
+ return;
+
+ final int[] pixels = buffer.pixels;
+ final float[] depth = buffer.depth;
+ final int backgroundAlpha = 255 - alpha;
+
+ final int redWithAlpha = color.r * alpha;
+ final int greenWithAlpha = color.g * alpha;
+ final int blueWithAlpha = color.b * alpha;
+
+ for (int relativeY = 0; relativeY <= lineHeight; relativeY++) {
+ final int y = yStart + relativeY;
+
+ if ((y >= buffer.renderMinY) && (y < buffer.renderMaxY)) {
+ if ((y >= 0) && (y < buffer.height)) {
+
+ final int x = xBase + ((relativeY * lineWidth) / lineHeight);
+ if ((x >= buffer.renderMinX) && (x < buffer.renderMaxX)) {
+ int offset = (y * buffer.width) + x;
+
+ // depth-test (never write): solids occlude lines
+ final double zw = zwA
+ + (((double) relativeY / lineHeight) * (zwB - zwA));
+ if (zw > depth[offset] - RenderingContext.DEPTH_MARGIN_DZ * zw * zw) {
+ final int dest = pixels[offset];
+ final int destR = (dest >> 16) & 0xff;
+ final int destG = (dest >> 8) & 0xff;
+ final int destB = dest & 0xff;
+
+ final int newR = ((destR * backgroundAlpha) + redWithAlpha) >> 8;
+ final int newG = ((destG * backgroundAlpha) + greenWithAlpha) >> 8;
+ final int newB = ((destB * backgroundAlpha) + blueWithAlpha) >> 8;
+
+ pixels[offset] = (newR << 16) | (newG << 8) | newB;
+ }
+ }
+ }
+ }
+ }
+ }
+
+ /**
+ * Finds the index of the first interpolator (starting from startPointer) that contains the given Y coordinate.
+ *
+ * @param lineInterpolators the interpolators array
+ * @param startPointer the index to start searching from
+ * @param y the Y coordinate to search for
+ * @return the index of the interpolator, or -1 if not found
+ */
+ private int getLineInterpolator(final LineInterpolator[] lineInterpolators,
+ final int startPointer, final int y) {
+
+ for (int i = startPointer; i < lineInterpolators.length; i++)
+ if (lineInterpolators[i].containsY(y))
+ return i;
+ return -1;
+ }
+
+ /**
+ * The thick-line path widens the line perpendicular to its direction by
+ * the projected endpoint radii, reaching beyond the vertex Y range.
+ * The thin paths stay within the vertex Y range, but there the radius
+ * is below 1 pixel anyway.
+ */
+ @Override
+ protected double getScreenYMargin(final RenderingContext renderingContext) {
+ final List<Vertex> clipped = clippedVertices(renderingContext);
+ final Vertex p1 = clipped != null ? clipped.get(0) : vertices.get(0);
+ final Vertex p2 = clipped != null ? clipped.get(1) : vertices.get(1);
+ final double point1radius = (renderingContext.width * LINE_WIDTH_MULTIPLIER * width)
+ / p1.transformedCoordinate(renderingContext).z;
+ final double point2radius = (renderingContext.width * LINE_WIDTH_MULTIPLIER * width)
+ / p2.transformedCoordinate(renderingContext).z;
+ return Math.max(point1radius, point2radius);
+ }
+
+ /**
+ * The thick-line widening is perpendicular to the line direction, so it
+ * reaches past the vertex range on the X axis exactly as much as on Y.
+ */
+ @Override
+ protected double getScreenXMargin(final RenderingContext renderingContext) {
+ return getScreenYMargin(renderingContext);
+ }
+
+ /**
+ * Renders this line to the screen using perspective-correct width and alpha blending.
+ *
+ * <p>This method handles two rendering modes:</p>
+ * <ul>
+ * <li>Thin lines: When the projected width is below threshold, draws single-pixel
+ * lines with alpha adjusted for sub-pixel appearance.</li>
+ * <li>Thick lines: Creates four edge interpolators and fills the rectangular area
+ * scanline by scanline with perspective-correct alpha fading at edges.</li>
+ * </ul>
+ *
+ * @param buffer the rendering context containing the pixel buffer
+ */
+ @Override
+ public void paint(final RenderingContext buffer) {
+ // Lines paint only in the alpha pass: they blend, depth-TEST
+ // against the opaque z-buffer (solid geometry occludes them),
+ // and never depth-WRITE (a line must not occlude later geometry).
+ if (buffer.depthPass == 1)
+ return;
+
+ // Near-plane clip output takes precedence: a straddling line is
+ // shortened to its in-front endpoint plus the intersection point.
+ final List<Vertex> clipped = clippedVertices(buffer);
+ final Vertex endpoint1 = clipped != null ? clipped.get(0) : vertices.get(0);
+ final Vertex endpoint2 = clipped != null ? clipped.get(1) : vertices.get(1);
+
+ final Point2D onScreenPoint1 = endpoint1.onScreenCoordinate(buffer);
+ final Point2D onScreenPoint2 = endpoint2.onScreenCoordinate(buffer);
+
+ final double xp = onScreenPoint2.x - onScreenPoint1.x;
+ final double yp = onScreenPoint2.y - onScreenPoint1.y;
+
+ final double z1 = endpoint1.transformedCoordinate(buffer).z;
+ final double z2 = endpoint2.transformedCoordinate(buffer).z;
+
+ final double point1radius = (buffer.width * LINE_WIDTH_MULTIPLIER * width) / z1;
+ final double point2radius = (buffer.width * LINE_WIDTH_MULTIPLIER * width) / z2;
+
+ // 1/z at the endpoints: interpolates linearly in screen space
+ // (projectively correct) — the basis for per-pixel depth tests.
+ final double zwP1 = 1d / z1;
+ final double zwP2 = 1d / z2;
+
+ if ((point1radius < MINIMUM_WIDTH_THRESHOLD)
+ || (point2radius < MINIMUM_WIDTH_THRESHOLD)) {
+
+ double averageRadius = (point1radius + point2radius) / 2;
+
+ if (averageRadius > 1)
+ averageRadius = 1;
+
+ final int alpha = (int) (color.a * averageRadius);
+ if (alpha < 2)
+ return;
+
+ if (Math.abs(xp) > Math.abs(yp))
+ drawSinglePixelHorizontalLine(buffer, alpha, onScreenPoint1, onScreenPoint2, zwP1, zwP2);
+ else
+ drawSinglePixelVerticalLine(buffer, alpha, onScreenPoint1, onScreenPoint2, zwP1, zwP2);
+ return;
+ }
+
+ final double lineLength = Math.sqrt((xp * xp) + (yp * yp));
+
+ final double yinc1 = (point1radius * xp) / lineLength;
+ final double yinc2 = (point2radius * xp) / lineLength;
+
+ final double xdec1 = (point1radius * yp) / lineLength;
+ final double xdec2 = (point2radius * yp) / lineLength;
+
+ final double p1x1 = onScreenPoint1.x - xdec1;
+ final double p1y1 = onScreenPoint1.y + yinc1;
+
+ final double p1x2 = onScreenPoint1.x + xdec1;
+ final double p1y2 = onScreenPoint1.y - yinc1;
+
+ final double p2x1 = onScreenPoint2.x - xdec2;
+ final double p2y1 = onScreenPoint2.y + yinc2;
+
+ final double p2x2 = onScreenPoint2.x + xdec2;
+ final double p2y2 = onScreenPoint2.y - yinc2;
+
+ // Get thread-local interpolators
+ final LineInterpolator[] lineInterpolators = LINE_INTERPOLATORS.get();
+
+ lineInterpolators[0].setPoints(p1x1, p1y1, 1d, p2x1, p2y1, 1d);
+ lineInterpolators[1].setPoints(p1x2, p1y2, -1d, p2x2, p2y2, -1d);
+
+ lineInterpolators[2].setPoints(p1x1, p1y1, 1d, p1x2, p1y2, -1d);
+ lineInterpolators[3].setPoints(p2x1, p2y1, 1d, p2x2, p2y2, -1d);
+
+ double ymin = p1y1;
+ if (p1y2 < ymin)
+ ymin = p1y2;
+ if (p2y1 < ymin)
+ ymin = p2y1;
+ if (p2y2 < ymin)
+ ymin = p2y2;
+ if (ymin < 0)
+ ymin = 0;
+
+ double ymax = p1y1;
+ if (p1y2 > ymax)
+ ymax = p1y2;
+ if (p2y1 > ymax)
+ ymax = p2y1;
+ if (p2y2 > ymax)
+ ymax = p2y2;
+ if (ymax >= buffer.height)
+ ymax = buffer.height - 1;
+
+ // clamp to render Y bounds
+ ymin = Math.max(ymin, buffer.renderMinY);
+ ymax = Math.min(ymax, buffer.renderMaxY - 1);
+ if (ymin > ymax)
+ return;
+
+ // 2D-line parameter gradients for per-pixel 1/z interpolation
+ final double len2 = (xp * xp) + (yp * yp);
+ final double dtDx = xp / len2;
+ final double dtDy = yp / len2;
+
+ for (int y = (int) ymin; y <= ymax; y++) {
+ final int li1 = getLineInterpolator(lineInterpolators, 0, y);
+ if (li1 != -1) {
+ final int li2 = getLineInterpolator(lineInterpolators, li1 + 1, y);
+ if (li2 != -1)
+ drawHorizontalLine(lineInterpolators[li1], lineInterpolators[li2], y,
+ buffer, onScreenPoint1.x, onScreenPoint1.y, dtDx, dtDy,
+ zwP1, zwP2 - zwP1);
+ }
+ }
+ }
+
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.line;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+
+
+/**
+ * Factory for creating Line objects with consistent appearance settings.
+ * <p>
+ * This class encapsulates common line styling parameters (width and color) to
+ * avoid redundant configuration. It provides multiple constructors for
+ * flexibility and ensures default values are used when not specified.
+ *
+ * <p><b>Example usage:</b></p>
+ * <pre>{@code
+ * // Create a line appearance with default color and width 2.0
+ * LineAppearance appearance = new LineAppearance(2.0, Color.RED);
+ *
+ * // Create multiple lines with the same appearance
+ * Line line1 = appearance.getLine(new Point3D(0, 0, 100), new Point3D(10, 0, 100));
+ * Line line2 = appearance.getLine(new Point3D(0, 10, 100), new Point3D(10, 10, 100));
+ *
+ * // Override color for a specific line
+ * Line blueLine = appearance.getLine(p1, p2, Color.BLUE);
+ * }</pre>
+ */
+public class LineAppearance {
+
+ private final double lineWidth;
+
+ private Color color = new Color(100, 100, 255, 255);
+
+ /**
+ * Creates a line appearance with default width (1.0) and default color (light blue).
+ */
+ public LineAppearance() {
+ lineWidth = 1;
+ }
+
+ /**
+ * Creates a line appearance with the specified width and default color (light blue).
+ *
+ * @param lineWidth the line width in world units
+ */
+ public LineAppearance(final double lineWidth) {
+ this.lineWidth = lineWidth;
+ }
+
+ /**
+ * Creates a line appearance with the specified width and color.
+ *
+ * @param lineWidth the line width in world units
+ * @param color the line color
+ */
+ public LineAppearance(final double lineWidth, final Color color) {
+ this.lineWidth = lineWidth;
+ this.color = color;
+ }
+
+ /**
+ * Creates a line between two points using this appearance's width and color.
+ *
+ * @param point1 the starting point of the line
+ * @param point2 the ending point of the line
+ * @return a new Line instance
+ */
+ public Line getLine(final Point3D point1, final Point3D point2) {
+ return new Line(point1, point2, color, lineWidth);
+ }
+
+ /**
+ * Creates a line between two points using this appearance's width and a custom color.
+ *
+ * @param point1 the starting point of the line
+ * @param point2 the ending point of the line
+ * @param color the color for this specific line (overrides the default)
+ * @return a new Line instance
+ */
+ public Line getLine(final Point3D point1, final Point3D point2,
+ final Color color) {
+ return new Line(point1, point2, color, lineWidth);
+ }
+
+ /**
+ * Returns the line width configured for this appearance.
+ *
+ * @return the line width in world units
+ */
+ public double getLineWidth() {
+ return lineWidth;
+ }
+
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.line;
+
+/**
+ * Interpolates between two points along a line for scanline rendering.
+ * <p>
+ * This class calculates screen coordinates and depth values (d) for a given Y
+ * position. It supports perspective-correct interpolation by tracking the
+ * distance between points and using it to compute step increments.
+ * <p>
+ * The comparison logic prioritizes interpolators with greater vertical coverage
+ * to optimize scanline ordering.
+ */
+public class LineInterpolator {
+
+ private double x1, y1, d1, x2, y2, d2;
+
+ private double d;
+ private int height;
+ private int width;
+ private double dinc;
+
+ /**
+ * Creates a new line interpolator with uninitialized endpoints.
+ */
+ public LineInterpolator() {
+ }
+
+ /**
+ * Checks if the given Y coordinate falls within the vertical span of this line.
+ *
+ * @param y the Y coordinate to test
+ * @return {@code true} if y is between y1 and y2 (inclusive)
+ */
+ public boolean containsY(final int y) {
+
+ if (y1 < y2) {
+ if (y >= y1)
+ return y <= y2;
+ } else if (y >= y2)
+ return y <= y1;
+
+ return false;
+ }
+
+ /**
+ * Returns the depth value (d) at the current Y position.
+ *
+ * @return the interpolated depth value
+ */
+ public double getD() {
+ return d;
+ }
+
+ /**
+ * Computes the X coordinate for the given Y position.
+ *
+ * @param y the Y coordinate
+ * @return the interpolated X coordinate
+ */
+ public int getX(final int y) {
+ if (height == 0)
+ return (int) (x2 + x1) / 2;
+
+ final int distanceFromY1 = y - (int) y1;
+
+ d = d1 + ((dinc * distanceFromY1) / height);
+
+ return (int) x1 + ((width * distanceFromY1) / height);
+ }
+
+ /**
+ * Sets the endpoints and depth values for this line interpolator.
+ *
+ * @param x1 the X coordinate of the first point
+ * @param y1 the Y coordinate of the first point
+ * @param d1 the depth value at the first point
+ * @param x2 the X coordinate of the second point
+ * @param y2 the Y coordinate of the second point
+ * @param d2 the depth value at the second point
+ */
+ public void setPoints(final double x1, final double y1, final double d1,
+ final double x2, final double y2, final double d2) {
+
+ this.x1 = x1;
+ this.y1 = y1;
+ this.d1 = d1;
+
+ this.x2 = x2;
+ this.y2 = y2;
+ this.d2 = d2;
+
+ height = (int) y2 - (int) y1;
+ width = (int) x2 - (int) x1;
+
+ dinc = d2 - d1;
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+
+/**
+ * 3D line segment rendering with perspective-correct width and alpha blending.
+ *
+ * <p>Lines are rendered with width that adjusts based on distance from the viewer.
+ * The rendering uses interpolators for smooth edges and proper alpha blending.</p>
+ *
+ * <p>Key classes:</p>
+ * <ul>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.line.Line} - The line shape</li>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.line.LineAppearance} - Color and width configuration</li>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.line.LineInterpolator} - Scanline edge interpolation</li>
+ * </ul>
+ *
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.line.Line
+ */
+
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.line;
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+
+/**
+ * Primitive shape implementations for the rasterization pipeline.
+ *
+ * <p>Basic shapes are the building blocks of 3D scenes. Each can be rendered
+ * independently and combined to create more complex objects.</p>
+ *
+ * <p>Subpackages:</p>
+ * <ul>
+ * <li>{@code line} - 3D line segments with perspective-correct width</li>
+ * <li>{@code solidpolygon} - Solid-color triangles with flat shading</li>
+ * <li>{@code texturedpolygon} - Triangles with UV-mapped textures</li>
+ * </ul>
+ *
+ * <p>Additional basic shapes:</p>
+ * <ul>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.Billboard} - Textures that always face the camera</li>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.GlowingPoint} - Circular gradient billboards</li>
+ * </ul>
+ *
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.Billboard
+ */
+
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic;
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point2D;
+
+import static java.lang.Math.round;
+
+/**
+ * Interpolates the x coordinate along a 2D line edge for scanline-based polygon rasterization.
+ *
+ * <p>{@code LineInterpolator} represents one edge of a polygon in screen space, defined by
+ * two {@link Point2D} endpoints. Given a scanline y coordinate, it computes the corresponding
+ * x coordinate via linear interpolation. This is a core building block for the solid polygon
+ * rasterizer, which fills triangles by sweeping horizontal scanlines and using two
+ * {@code LineInterpolator} instances to find the left and right x boundaries at each y level.</p>
+ *
+ * <p><b>Subpixel precision:</b> This class uses double-precision arithmetic throughout
+ * the interpolation pipeline to eliminate T-junction gaps. Vertices that should be at the
+ * same position but land at slightly different screen coordinates (e.g., 100.4 vs 100.6)
+ * will produce consistent interpolated results when rounded, ensuring adjacent polygons
+ * fill seamlessly without gaps.</p>
+ *
+ * <p>Instances are {@link Comparable}, sorted by absolute height (tallest first) and then
+ * by width. This ordering is used during rasterization to select the primary (longest) edge
+ * of the triangle for the outer scanline loop.</p>
+ *
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon.SolidPolygon
+ * @see Point2D
+ */
+public class LineInterpolator {
+
+ /**
+ * Small epsilon value for comparing near-zero heights to detect horizontal edges.
+ */
+ private static final double EPSILON = 0.0001;
+ /**
+ * The first endpoint of this edge.
+ */
+ Point2D p1;
+ /**
+ * The second endpoint of this edge.
+ */
+ Point2D p2;
+ /**
+ * The vertical span (p2.y - p1.y) in double precision, which may be negative.
+ *
+ * <p>Stored as double to preserve subpixel precision during interpolation,
+ * eliminating rounding errors that cause T-junction gaps.</p>
+ */
+ private double height;
+ /**
+ * The horizontal span (p2.x - p1.x) in double precision, which may be negative.
+ *
+ * <p>Stored as double to preserve subpixel precision during interpolation.</p>
+ */
+ private double width;
+
+ /**
+ * 1/z (the depth-buffer quantity) at the endpoints. Linear in screen
+ * space, so it rides the same edge interpolation as x; set only via
+ * {@link #setPointsZW} when the polygon participates in the z-buffer.
+ */
+ private double zw1;
+ private double zw2;
+ private double zwSpan;
+
+ /**
+ * Creates a new line interpolator with uninitialized endpoints.
+ */
+ public LineInterpolator() {
+ }
+
+ /**
+ * Tests whether the given y coordinate falls within the vertical span of this edge.
+ *
+ * <p>Uses double-precision comparison to handle subpixel vertex positions correctly.</p>
+ *
+ * @param y the scanline y coordinate to test
+ * @return {@code true} if {@code y} is between the y coordinates of the two endpoints (inclusive)
+ */
+ public boolean containsY(final int y) {
+ final double minY = Math.min(p1.y, p2.y);
+ final double maxY = Math.max(p1.y, p2.y);
+ return y >= minY && y <= maxY;
+ }
+
+ /**
+ * Computes the interpolated x coordinate rounded to the nearest integer.
+ *
+ * <p>For horizontal edges (height near zero), returns the midpoint x value
+ * to avoid division by zero. This case should only occur when the edge
+ * spans exactly one scanline.</p>
+ *
+ * @param y the scanline y coordinate
+ * @return the interpolated x coordinate rounded to the nearest integer
+ */
+ public int getX(final int y) {
+ if (Math.abs(height) < EPSILON) {
+ return (int) round((p1.x + p2.x) / 2);
+ }
+ return (int) round(p1.x + (width * (y - p1.y)) / height);
+ }
+
+ /**
+ * Sets the two endpoints of this edge and precomputes the width, height, and absolute height.
+ *
+ * <p>This method stores the endpoints directly and computes spans using double-precision
+ * arithmetic from the Point2D coordinates.</p>
+ *
+ * @param p1 the first endpoint
+ * @param p2 the second endpoint
+ */
+ public void setPoints(final Point2D p1, final Point2D p2) {
+ this.p1 = p1;
+ this.p2 = p2;
+ height = p2.y - p1.y;
+ width = p2.x - p1.x;
+ }
+
+ /**
+ * Sets the depth-buffer endpoint values (1/z) for this edge.
+ * Companion to {@link #setPoints}; call after it.
+ *
+ * @param zw1 1/z at {@code p1}
+ * @param zw2 1/z at {@code p2}
+ */
+ public void setPointsZW(final double zw1, final double zw2) {
+ this.zw1 = zw1;
+ this.zw2 = zw2;
+ zwSpan = zw2 - zw1;
+ }
+
+ /**
+ * Computes the interpolated 1/z (depth value) at the given scanline.
+ * Uses the same interpolation parameter as {@link #getX}, so depth
+ * and x stay consistent along the edge.
+ *
+ * @param y the scanline y coordinate
+ * @return the interpolated 1/z
+ */
+ public double getZW(final int y) {
+ if (Math.abs(height) < EPSILON) {
+ return (zw1 + zw2) / 2d;
+ }
+ return zw1 + (zwSpan * (y - p1.y)) / height;
+ }
+
+}
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon;
+
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.Plane;
+import eu.svjatoslav.aukio.e3d.geometry.Point2D;
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.RenderingContext;
+import eu.svjatoslav.aukio.e3d.gui.humaninput.MouseInteractionController;
+import eu.svjatoslav.aukio.e3d.math.TransformStack;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Vertex;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+import eu.svjatoslav.aukio.e3d.renderer.raster.RenderAggregator;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.AbstractCoordinateShape;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+import static eu.svjatoslav.aukio.e3d.geometry.Polygon.pointWithinPolygon;
+
+/**
+ * A solid-color convex polygon renderer supporting N vertices (N >= 3).
+ *
+ * <p>This class serves as the unified polygon type for both rendering and CSG operations.
+ * It renders convex polygons by decomposing them into triangles using fan triangulation,
+ * and supports CSG operations directly without conversion to intermediate types.</p>
+ *
+ * <p><b>Rendering:</b></p>
+ * <ul>
+ * <li>Fan triangulation for N-vertex polygons (N-2 triangles)</li>
+ * <li>Scanline rasterization with per-pixel z-buffering and alpha blending</li>
+ * <li>Backface culling and flat shading support</li>
+ * <li>Mouse interaction via point-in-polygon testing</li>
+ * </ul>
+ *
+ * <p><b>CSG Support:</b></p>
+ * <ul>
+ * <li>Lazy-computed plane for BSP operations</li>
+ * <li>{@link #flip()} for inverting polygon orientation</li>
+ * <li>{@link #deepClone()} for creating independent copies</li>
+ * </ul>
+ *
+ * <p><b>Usage examples:</b></p>
+ * <pre>{@code
+ * // Create a triangle
+ * SolidPolygon triangle = new SolidPolygon(
+ * new Point3D(0, 0, 0),
+ * new Point3D(50, 0, 0),
+ * new Point3D(25, 50, 0),
+ * Color.RED
+ * );
+ *
+ * // Create a quad
+ * SolidPolygon quad = SolidPolygon.quad(
+ * new Point3D(-50, -50, 0),
+ * new Point3D(50, -50, 0),
+ * new Point3D(50, 50, 0),
+ * new Point3D(-50, 50, 0),
+ * Color.BLUE
+ * );
+ *
+ * // Use with CSG (via AbstractCompositeShape)
+ * SolidPolygonRectangularBox box = new SolidPolygonRectangularBox(...);
+ * box.subtract(sphere);
+ * }</pre>
+ *
+ * @see Plane for BSP plane operations
+ * @see LineInterpolator for scanline edge interpolation
+ */
+public class SolidPolygon extends AbstractCoordinateShape {
+
+ /**
+ * Thread-local storage for line interpolators used during scanline rasterization.
+ *
+ * <p>Contains three interpolators representing the three edges of a triangle.
+ * ThreadLocal ensures thread safety when multiple threads render triangles
+ * concurrently, avoiding allocation during rendering by reusing these objects.</p>
+ */
+ private static final ThreadLocal<LineInterpolator[]> INTERPOLATORS =
+ ThreadLocal.withInitial(() -> new LineInterpolator[]{
+ new LineInterpolator(), new LineInterpolator(), new LineInterpolator()
+ });
+ /**
+ * Thread-local storage for screen coordinates during rendering.
+ * Each rendering thread gets its own array to avoid race conditions.
+ */
+ private static final ThreadLocal<Point2D[]> SCREEN_POINTS = new ThreadLocal<>();
+ /**
+ * Reusable color for shading calculations.
+ * Computed once during transform phase, used during paint phase.
+ */
+ private final Color shadedColor = new Color();
+ /**
+ * Reusable point for polygon center calculation.
+ */
+ private final Point3D cachedCenter = new Point3D();
+ /**
+ * Reusable point for polygon normal calculation.
+ */
+ private final Point3D cachedNormal = new Point3D();
+ /**
+ * Cached plane containing this polygon, used for BSP operations.
+ *
+ * <p>Lazy-computed on first call to {@link #getPlane()}.</p>
+ */
+ private Plane plane;
+ /**
+ * The fill color of this polygon.
+ */
+ private Color color;
+ /**
+ * Whether flat shading is enabled for this polygon.
+ */
+ private boolean shadingEnabled = false;
+
+ /**
+ * Whether backface culling is enabled for this polygon.
+ */
+ private boolean backfaceCulling = false;
+
+ // ==================== CONSTRUCTORS ====================
+
+ /**
+ * Creates a solid polygon with the specified vertices and color.
+ *
+ * @param vertices the vertices defining the polygon (must have at least 3)
+ * @param color the fill color of the polygon
+ * @throws IllegalArgumentException if vertices is null or has fewer than 3 vertices
+ */
+ public SolidPolygon(final Point3D[] vertices, final Color color) {
+ super(createVerticesFromPoints(vertices));
+ if (vertices == null || vertices.length < 3) {
+ throw new IllegalArgumentException(
+ "Polygon must have at least 3 vertices, but got "
+ + (vertices == null ? "null" : vertices.length));
+ }
+ this.color = color;
+ }
+
+ /**
+ * Creates a solid polygon from a list of points and color.
+ *
+ * @param points the list of points defining the polygon (must have at least 3)
+ * @param color the fill color of the polygon
+ * @throws IllegalArgumentException if points is null or has fewer than 3 points
+ */
+ public SolidPolygon(final List<Point3D> points, final Color color) {
+ super(createVerticesFromPoints(points));
+ if (points == null || points.size() < 3) {
+ throw new IllegalArgumentException(
+ "Polygon must have at least 3 vertices, but got "
+ + (points == null ? "null" : points.size()));
+ }
+ this.color = color;
+ }
+
+ /**
+ * Private constructor for creating a polygon from existing vertices.
+ *
+ * <p>Parameter order (color first) avoids erasure conflict with
+ * {@link #SolidPolygon(List, Color)} which takes List<Point3D>.</p>
+ *
+ * @param color the fill color of the polygon
+ * @param vertices the list of Vertex objects (used directly, not copied)
+ */
+ private SolidPolygon(final Color color, final List<Vertex> vertices) {
+ super(vertices);
+ this.color = color;
+ }
+
+ /**
+ * Creates a solid triangle with the specified vertices and color.
+ *
+ * @param point1 the first vertex position
+ * @param point2 the second vertex position
+ * @param point3 the third vertex position
+ * @param color the fill color
+ */
+ public SolidPolygon(final Point3D point1, final Point3D point2,
+ final Point3D point3, final Color color) {
+ super(new Vertex(point1), new Vertex(point2), new Vertex(point3));
+ this.color = color;
+ }
+
+ /**
+ * Creates a solid polygon from existing vertices.
+ *
+ * <p>Used for CSG operations and cloning where vertices already exist.
+ * The vertex list is used directly (not copied), so callers should not
+ * modify the list after passing it to this method.</p>
+ *
+ * @param vertices the list of Vertex objects (used directly, not copied)
+ * @param color the fill color of the polygon
+ * @return a new SolidPolygon with the given vertices (shading disabled by default)
+ * @throws IllegalArgumentException if vertices is null or has fewer than 3 vertices
+ */
+ public static SolidPolygon fromVertices(final List<Vertex> vertices, final Color color) {
+ return fromVertices(vertices, color, false);
+ }
+
+ /**
+ * Creates a solid polygon from existing vertices with specified shading.
+ *
+ * <p>Used for CSG operations and cloning where vertices already exist.
+ * The vertex list is used directly (not copied), so callers should not
+ * modify the list after passing it to this method.</p>
+ *
+ * @param vertices the list of Vertex objects (used directly, not copied)
+ * @param color the fill color of the polygon
+ * @param shadingEnabled whether shading is enabled for this polygon
+ * @return a new SolidPolygon with the given vertices and shading setting
+ * @throws IllegalArgumentException if vertices is null or has fewer than 3 vertices
+ */
+ public static SolidPolygon fromVertices(final List<Vertex> vertices, final Color color,
+ final boolean shadingEnabled) {
+ if (vertices == null || vertices.size() < 3) {
+ throw new IllegalArgumentException(
+ "Polygon must have at least 3 vertices, but got "
+ + (vertices == null ? "null" : vertices.size()));
+ }
+ final SolidPolygon polygon = new SolidPolygon(color, vertices);
+ polygon.setShadingEnabled(shadingEnabled);
+ return polygon;
+ }
+
+ // ==================== STATIC FACTORY METHODS ====================
+
+ /**
+ * Creates a triangle (3-vertex polygon).
+ *
+ * @param p1 the first vertex
+ * @param p2 the second vertex
+ * @param p3 the third vertex
+ * @param color the fill color
+ * @return a new SolidPolygon with 3 vertices
+ */
+ public static SolidPolygon triangle(final Point3D p1, final Point3D p2,
+ final Point3D p3, final Color color) {
+ return new SolidPolygon(p1, p2, p3, color);
+ }
+
+ /**
+ * Creates a quad (4-vertex polygon).
+ *
+ * @param p1 the first vertex
+ * @param p2 the second vertex
+ * @param p3 the third vertex
+ * @param p4 the fourth vertex
+ * @param color the fill color
+ * @return a new SolidPolygon with 4 vertices
+ */
+ public static SolidPolygon quad(final Point3D p1, final Point3D p2,
+ final Point3D p3, final Point3D p4, final Color color) {
+ return new SolidPolygon(new Point3D[]{p1, p2, p3, p4}, color);
+ }
+
+ // ==================== VERTEX HELPER METHODS ====================
+
+ /**
+ * Helper method to create Vertex list from Point3D array.
+ */
+ private static List<Vertex> createVerticesFromPoints(final Point3D[] points) {
+ if (points == null || points.length < 3) {
+ return new ArrayList<>();
+ }
+ final List<Vertex> verts = new ArrayList<>(points.length);
+ for (final Point3D point : points) {
+ verts.add(new Vertex(point));
+ }
+ return verts;
+ }
+
+ /**
+ * Helper method to create Vertex list from Point3D list.
+ */
+ private static List<Vertex> createVerticesFromPoints(final List<Point3D> points) {
+ if (points == null || points.size() < 3) {
+ return new ArrayList<>();
+ }
+ final List<Vertex> verts = new ArrayList<>(points.size());
+ for (final Point3D point : points) {
+ verts.add(new Vertex(point));
+ }
+ return verts;
+ }
+
+ /**
+ * Draws a horizontal scanline between two edge interpolators with alpha
+ * blending and per-pixel depth testing.
+ *
+ * <p>The 1/z endpoint values ride the interpolators' zw channel; every
+ * pixel is depth-tested before writing. Opaque pixels write depth (pass
+ * 1), translucent pixels blend without a depth write (pass 2), so
+ * translucency never occludes.</p>
+ *
+ * @param line1 the left edge interpolator
+ * @param line2 the right edge interpolator
+ * @param y the Y coordinate of the scanline
+ * @param renderBuffer the rendering context to draw into
+ * @param color the color to draw with
+ */
+ private static void drawHorizontalLine(final LineInterpolator line1,
+ final LineInterpolator line2, final int y,
+ final RenderingContext renderBuffer, final Color color) {
+
+ int x1 = line1.getX(y);
+ int x2 = line2.getX(y);
+
+ double zw1 = line1.getZW(y);
+ double zw2 = line2.getZW(y);
+
+ if (x1 > x2) {
+ final int tmp = x1;
+ x1 = x2;
+ x2 = tmp;
+ final double tmpZw = zw1;
+ zw1 = zw2;
+ zw2 = tmpZw;
+ }
+
+ final double realX1 = x1;
+ final double realWidth = x2 - x1;
+
+ if (x1 < renderBuffer.renderMinX) x1 = renderBuffer.renderMinX;
+
+ // x2 is exclusive (loop paints [x1, x2)): clamp to renderMaxX,
+ // not renderMaxX-1, or the rightmost tile column stays unpainted
+ if (x2 >= renderBuffer.renderMaxX) x2 = renderBuffer.renderMaxX;
+
+ final int width = x2 - x1;
+ if (width <= 0)
+ return;
+
+ int offset = (y * renderBuffer.width) + x1;
+ final int[] pixels = renderBuffer.pixels;
+ final float[] depth = renderBuffer.depth;
+ // Alpha pass (depthPass 2): depth-test but never depth-write
+ final boolean writeDepth = renderBuffer.depthPass != 2;
+
+ final double dzw = (zw2 - zw1) / realWidth;
+ double zw = zw1 + dzw * (x1 - realX1);
+
+ final int polygonAlpha = color.a;
+ final int r = color.r;
+ final int g = color.g;
+ final int b = color.b;
+
+ if (polygonAlpha == 255) {
+ final int pixel = (r << 16) | (g << 8) | b;
+ for (int i = 0; i < width; i++) {
+ if (zw > depth[offset] - RenderingContext.DEPTH_MARGIN_DZ * zw * zw) {
+ pixels[offset] = pixel;
+ if (writeDepth)
+ depth[offset] = (float) zw;
+ }
+ offset++;
+ zw += dzw;
+ }
+ } else {
+ final int backgroundAlpha = 255 - polygonAlpha;
+
+ final int redWithAlpha = r * polygonAlpha;
+ final int greenWithAlpha = g * polygonAlpha;
+ final int blueWithAlpha = b * polygonAlpha;
+
+ // Blend form ((255-a)*dest + a*src) >> 8. Proven bit-identical
+ // to TexturedTriangle's lerp form dest + ((a*(src-dest) - dest)
+ // >> 8) for every (a,src,dest) — do NOT "fix" one to match the
+ // other cosmetically; both are the same formula.
+ for (int i = 0; i < width; i++) {
+ if (zw > depth[offset] - RenderingContext.DEPTH_MARGIN_DZ * zw * zw) {
+ final int dest = pixels[offset];
+ final int destR = (dest >> 16) & 0xff;
+ final int destG = (dest >> 8) & 0xff;
+ final int destB = dest & 0xff;
+
+ final int newR = ((destR * backgroundAlpha) + redWithAlpha) >> 8;
+ final int newG = ((destG * backgroundAlpha) + greenWithAlpha) >> 8;
+ final int newB = ((destB * backgroundAlpha) + blueWithAlpha) >> 8;
+
+ pixels[offset] = (newR << 16) | (newG << 8) | newB;
+ }
+ offset++;
+ zw += dzw;
+ }
+ }
+ }
+
+ /**
+ * Renders a triangle using scanline rasterization.
+ *
+ * <p>This static method handles:</p>
+ * <ul>
+ * <li>Rounding vertices to integer screen coordinates</li>
+ * <li>Mouse hover detection via point-in-triangle test</li>
+ * <li>Viewport clipping</li>
+ * <li>Scanline rasterization with per-pixel z-buffering and alpha blending</li>
+ * </ul>
+ *
+ * @param context the rendering context
+ * @param onScreenPoint1 the first vertex in screen coordinates
+ * @param onScreenPoint2 the second vertex in screen coordinates
+ * @param onScreenPoint3 the third vertex in screen coordinates
+ * @param z1 camera-space z of the first vertex
+ * @param z2 camera-space z of the second vertex
+ * @param z3 camera-space z of the third vertex
+ * @param mouseInteractionController optional controller for mouse events, or null
+ * @param color the fill color
+ */
+ public static void drawTriangle(final RenderingContext context,
+ final Point2D onScreenPoint1, final Point2D onScreenPoint2,
+ final Point2D onScreenPoint3,
+ final double z1, final double z2, final double z3,
+ final MouseInteractionController mouseInteractionController,
+ final Color color) {
+
+ if (mouseInteractionController != null)
+ if (context.getMouseEvent() != null)
+ if (pointWithinPolygon(context.getMouseEvent().coordinate, onScreenPoint1, onScreenPoint2, onScreenPoint3))
+ context.setCurrentObjectUnderMouseCursor(mouseInteractionController);
+
+ if (color.isTransparent()) return;
+
+ // Copy coordinates to local variables (don't modify original Point2D)
+ // Keep double precision to eliminate T-junction gaps from truncation errors
+ final double y1 = onScreenPoint1.y;
+ final double y2 = onScreenPoint2.y;
+ final double y3 = onScreenPoint3.y;
+
+ // Find top-most point (use ceil to include all pixels triangle touches)
+ int yTop = (int) Math.ceil(Math.min(y1, Math.min(y2, y3)));
+ if (yTop < 0) yTop = 0;
+
+ // Find bottom-most point (use floor to include all pixels triangle touches)
+ int yBottom = (int) Math.floor(Math.max(y1, Math.max(y2, y3)));
+ if (yBottom >= context.height) yBottom = context.height - 1;
+
+ // Clamp to render Y bounds (use renderMaxY - 1 because loop is inclusive)
+ yTop = Math.max(yTop, context.renderMinY);
+ yBottom = Math.min(yBottom, context.renderMaxY - 1);
+ if (yTop > yBottom) return;
+
+ // Paint using line interpolators
+ final LineInterpolator[] interp = INTERPOLATORS.get();
+ final LineInterpolator li1 = interp[0];
+ final LineInterpolator li2 = interp[1];
+ final LineInterpolator li3 = interp[2];
+ li1.setPoints(onScreenPoint1, onScreenPoint2);
+ li2.setPoints(onScreenPoint1, onScreenPoint3);
+ li3.setPoints(onScreenPoint2, onScreenPoint3);
+
+ // 1/z rides the same edge interpolation; spans depth-test per pixel
+ li1.setPointsZW(1d / z1, 1d / z2);
+ li2.setPointsZW(1d / z1, 1d / z3);
+ li3.setPointsZW(1d / z2, 1d / z3);
+
+ for (int y = yTop; y <= yBottom; y++) {
+ if (li1.containsY(y)) {
+ if (li2.containsY(y)) {
+ drawHorizontalLine(li1, li2, y, context, color);
+ } else if (li3.containsY(y)) {
+ drawHorizontalLine(li1, li3, y, context, color);
+ }
+ } else if (li2.containsY(y)) {
+ if (li3.containsY(y)) {
+ drawHorizontalLine(li2, li3, y, context, color);
+ }
+ }
+ }
+ }
+
+ /**
+ * Returns the number of vertices in this polygon.
+ *
+ * @return the vertex count
+ */
+ public int getVertexCount() {
+ return vertices.size();
+ }
+
+ /**
+ * Returns the fill color of this polygon.
+ *
+ * @return the polygon color
+ */
+ public Color getColor() {
+ return color;
+ }
+
+ /**
+ * Sets the fill color of this polygon.
+ *
+ * @param color the new color
+ */
+ public void setColor(final Color color) {
+ this.color = color;
+ }
+
+ /**
+ * Checks if shading is enabled for this polygon.
+ *
+ * @return true if shading is enabled, false otherwise
+ */
+ public boolean isShadingEnabled() {
+ return shadingEnabled;
+ }
+
+ /**
+ * Enables or disables shading for this polygon.
+ *
+ * @param shadingEnabled true to enable shading, false to disable
+ */
+ public void setShadingEnabled(final boolean shadingEnabled) {
+ this.shadingEnabled = shadingEnabled;
+ }
+
+ // ==================== CSG SUPPORT ====================
+
+ /**
+ * Checks if backface culling is enabled for this polygon.
+ *
+ * @return {@code true} if backface culling is enabled
+ */
+ public boolean isBackfaceCullingEnabled() {
+ return backfaceCulling;
+ }
+
+ /**
+ * Enables or disables backface culling for this polygon.
+ *
+ * @param backfaceCulling {@code true} to enable backface culling
+ */
+ public void setBackfaceCulling(final boolean backfaceCulling) {
+ this.backfaceCulling = backfaceCulling;
+ }
+
+ /**
+ * Returns the plane containing this polygon.
+ *
+ * <p>Computed from the first three vertices and cached for reuse.
+ * Used by BSP tree construction for spatial partitioning.</p>
+ *
+ * @return the Plane containing this polygon
+ */
+ public Plane getPlane() {
+ if (plane == null) {
+ plane = Plane.fromPoints(
+ vertices.get(0).coordinate,
+ vertices.get(1).coordinate,
+ vertices.get(2).coordinate
+ );
+ }
+ return plane;
+ }
+
+ // ==================== RENDERING ====================
+
+ /**
+ * Flips the orientation of this polygon.
+ *
+ * <p>Reverses the vertex order and negates vertex normals.
+ * Also flips the cached plane if computed. Used during CSG operations
+ * when inverting solids.</p>
+ */
+ public void flip() {
+ Collections.reverse(vertices);
+ for (final Vertex vertex : vertices) vertex.flip();
+ if (plane != null) plane.flip();
+ }
+
+ /**
+ * Creates a deep clone of this polygon.
+ *
+ * <p>Clones all vertices and preserves the color, shading, and backface culling settings.
+ * Used by CSG operations to create independent copies before modification.</p>
+ *
+ * @return a new SolidPolygon with cloned data and preserved settings
+ */
+ public SolidPolygon deepClone() {
+ final List<Vertex> clonedVertices = new ArrayList<>(vertices.size());
+ for (final Vertex v : vertices) {
+ clonedVertices.add(v.clone());
+ }
+ final SolidPolygon clone = SolidPolygon.fromVertices(clonedVertices, color, shadingEnabled);
+ clone.backfaceCulling = this.backfaceCulling;
+ return clone;
+ }
+
+ /**
+ * Calculates the centroid (geometric center) of this polygon.
+ *
+ * @param result the point to store the center in
+ */
+ private void calculateCenter(final Point3D result) {
+ if (vertices.isEmpty()) {
+ result.x = result.y = result.z = 0;
+ return;
+ }
+
+ double sumX = 0, sumY = 0, sumZ = 0;
+ for (final Vertex v : vertices) {
+ sumX += v.coordinate.x;
+ sumY += v.coordinate.y;
+ sumZ += v.coordinate.z;
+ }
+
+ result.x = sumX / vertices.size();
+ result.y = sumY / vertices.size();
+ result.z = sumZ / vertices.size();
+ }
+
+ /**
+ * Calculates the signed area of this polygon in screen space.
+ *
+ * @param screenPoints the screen coordinates of this polygon's vertices
+ * @param vertexCount the number of vertices in the polygon
+ * @return the signed area (negative = front-facing in Y-down coordinate system)
+ */
+ private double calculateSignedArea(final Point2D[] screenPoints, final int vertexCount) {
+ double area = 0;
+ final int n = vertexCount;
+ for (int i = 0; i < n; i++) {
+ final Point2D curr = screenPoints[i];
+ final Point2D next = screenPoints[(i + 1) % n];
+ area += curr.x * next.y - next.x * curr.y;
+ }
+ return area / 2.0;
+ }
+
+ /**
+ * Tests whether a point lies inside this polygon using ray-casting.
+ *
+ * @param point the point to test
+ * @param screenPoints the screen coordinates of this polygon's vertices
+ * @param vertexCount the number of vertices in the polygon
+ * @return {@code true} if the point is inside the polygon
+ */
+ private boolean isPointInsidePolygon(final Point2D point, final Point2D[] screenPoints,
+ final int vertexCount) {
+ int intersectionCount = 0;
+ final int n = vertexCount;
+
+ for (int i = 0; i < n; i++) {
+ final Point2D p1 = screenPoints[i];
+ final Point2D p2 = screenPoints[(i + 1) % n];
+
+ if (intersectsRay(point, p1, p2)) {
+ intersectionCount++;
+ }
+ }
+
+ return (intersectionCount % 2) == 1;
+ }
+
+ /**
+ * Tests if a horizontal ray from the point intersects the edge.
+ */
+ private boolean intersectsRay(final Point2D point, Point2D edgeP1, Point2D edgeP2) {
+ if (edgeP1.y > edgeP2.y) {
+ final Point2D tmp = edgeP1;
+ edgeP1 = edgeP2;
+ edgeP2 = tmp;
+ }
+
+ if (point.y < edgeP1.y || point.y > edgeP2.y) {
+ return false;
+ }
+
+ final double dy = edgeP2.y - edgeP1.y;
+ if (Math.abs(dy) < 0.0001) {
+ return false;
+ }
+
+ final double t = (point.y - edgeP1.y) / dy;
+ final double intersectX = edgeP1.x + t * (edgeP2.x - edgeP1.x);
+
+ return point.x >= intersectX;
+ }
+
+ /**
+ * Renders this polygon to the screen.
+ *
+ * @param renderBuffer the rendering context containing the pixel buffer
+ */
+ @Override
+ public void paint(final RenderingContext renderBuffer) {
+ // Near-plane clip output takes precedence: a straddling triangle
+ // becomes a triangle or quad of in-front vertices; the original
+ // vertices hold behind-camera positions with garbage projections.
+ final List<Vertex> clipped = clippedVertices(renderBuffer);
+ final List<Vertex> active = clipped != null ? clipped : vertices;
+
+ if (active.size() < 3 || color.isTransparent()) {
+ return;
+ }
+
+ // Use pre-computed shaded color (computed during transform phase)
+ final Color paintColor = shadingEnabled ? shadedColor : color;
+
+ // Z-buffer two-pass classification: opaque polygons paint in
+ // pass 1 (depth test + write), translucent ones in pass 2
+ // (depth test, no write — translucency must not occlude).
+ // See RenderAggregator.paintSorted.
+ final boolean alphaClass = paintColor.a != 255;
+ if ((renderBuffer.depthPass == 1) == alphaClass)
+ return;
+
+ // Get thread-local screen points array
+ final Point2D[] screenPoints = getScreenPoints(active.size());
+ final double[] cameraZ = getCameraZ(active.size());
+
+ // Get screen coordinates and per-vertex depth
+ for (int i = 0; i < active.size(); i++) {
+ final Vertex vertex = active.get(i);
+ screenPoints[i] = vertex.onScreenCoordinate(renderBuffer);
+ cameraZ[i] = vertex.transformedCoordinate(renderBuffer).z;
+ }
+
+ // Backface culling check
+ if (backfaceCulling) {
+ final double signedArea = calculateSignedArea(screenPoints, active.size());
+ if (signedArea >= 0) {
+ return;
+ }
+ }
+
+ // Mouse interaction
+ if (mouseInteractionController != null && renderBuffer.getMouseEvent() != null) {
+ if (isPointInsidePolygon(renderBuffer.getMouseEvent().coordinate, screenPoints, active.size())) {
+ renderBuffer.setCurrentObjectUnderMouseCursor(mouseInteractionController);
+ }
+ }
+
+ // Only triangles can be rendered directly; N-vertex polygons must be triangulated
+ // by AbstractCompositeShape.rebuildRenderList() before rendering. The single
+ // exception: near-plane clipping can turn a renderable triangle into a quad
+ // (one corner cut off), painted here as a 2-triangle fan — the clip of a
+ // convex polygon stays convex, so fan triangulation is exact.
+ if (clipped == null && active.size() != 3) {
+ throw new IllegalStateException(
+ "SolidPolygon with " + active.size() + " vertices cannot be rendered directly. "
+ + "Only triangles (3 vertices) support direct rendering. "
+ + "For N-vertex polygons, use AbstractCompositeShape which triangulates when building its render list.");
+ }
+
+ for (int i = 1; i + 1 < active.size(); i++) {
+ drawTriangle(renderBuffer, screenPoints[0], screenPoints[i], screenPoints[i + 1],
+ cameraZ[0], cameraZ[i], cameraZ[i + 1],
+ mouseInteractionController, paintColor);
+ }
+ }
+
+ /**
+ * Thread-local storage for per-vertex camera-space z during rendering.
+ */
+ private static final ThreadLocal<double[]> CAMERA_Z = new ThreadLocal<>();
+
+ /**
+ * Gets a thread-local camera-z array sized for the given number of vertices.
+ *
+ * @param size the required array size
+ * @return a thread-local double array
+ */
+ private double[] getCameraZ(final int size) {
+ double[] cameraZ = CAMERA_Z.get();
+ if (cameraZ == null || cameraZ.length < size) {
+ cameraZ = new double[size];
+ CAMERA_Z.set(cameraZ);
+ }
+ return cameraZ;
+ }
+
+ /**
+ * Gets a thread-local screen points array sized for the given number of vertices.
+ *
+ * @param size the required array size
+ * @return a thread-local Point2D array
+ */
+ private Point2D[] getScreenPoints(final int size) {
+ Point2D[] screenPoints = SCREEN_POINTS.get();
+ if (screenPoints == null || screenPoints.length < size) {
+ screenPoints = new Point2D[size];
+ SCREEN_POINTS.set(screenPoints);
+ }
+ return screenPoints;
+ }
+
+ /**
+ * Transforms vertices to screen space and computes lighting once per frame.
+ *
+ * <p>Overrides parent to add lighting computation during the single-threaded
+ * transform phase. This ensures lighting is calculated only once per polygon
+ * per frame, rather than once per render thread.</p>
+ *
+ * @param transforms the transform stack to apply
+ * @param aggregator the render aggregator to queue shapes into
+ * @param renderingContext the rendering context
+ */
+ @Override
+ public void transform(final TransformStack transforms,
+ final RenderAggregator aggregator,
+ final RenderingContext renderingContext) {
+ // Transform vertices to screen space
+ super.transform(transforms, aggregator, renderingContext);
+
+ // Compute lighting once during transform phase (single-threaded)
+ if (shadingEnabled && renderingContext.lightingManager != null) {
+ calculateCenter(cachedCenter);
+ // Compute normal from first 3 vertices
+ Plane.computeNormal(
+ vertices.get(0).coordinate,
+ vertices.get(1).coordinate,
+ vertices.get(2).coordinate,
+ cachedNormal
+ );
+ renderingContext.lightingManager.computeLighting(
+ this, cachedCenter, cachedNormal, color, shadedColor);
+ }
+ }
+}
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+
+/**
+ * Solid-color polygon rendering with scanline rasterization.
+ *
+ * <p>SolidPolygon is the unified polygon type for both rendering and CSG operations.
+ * It supports N vertices (N >= 3) and handles perspective-correct interpolation,
+ * alpha blending, viewport clipping, backface culling, and optional flat shading.</p>
+ *
+ * <p>Key classes:</p>
+ * <ul>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon.SolidPolygon} - Unified polygon for rendering and CSG</li>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon.LineInterpolator} - Edge interpolation for scanlines</li>
+ * </ul>
+ *
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon.SolidPolygon
+ */
+
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon;
\ No newline at end of file
--- /dev/null
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.texturedpolygon;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point2D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.RenderingContext;
+import eu.svjatoslav.aukio.e3d.renderer.raster.RenderAggregator;
+import eu.svjatoslav.aukio.e3d.math.TransformStack;
+
+/**
+ * Paint/sort handle for one triangle of a {@link TriangleMeshBlock}. The
+ * triangle's geometry lives in the block's flat arrays (SoA layout); this
+ * object exists only so the existing sort/bin/paint pipeline — typed on
+ * individual shapes — can address one triangle. Handles are allocated once
+ * at block build time and reused every frame; {@link #transform} is a
+ * no-op because the block transforms all its triangles in one tight loop.
+ *
+ * <p>Per-slot screen data is read from the block's arrays through the
+ * overridden accessors, so the Z-comparator and tile binning see exactly
+ * the values an object-backed {@link TexturedTriangle} would expose.</p>
+ */
+final class MeshTriangle extends TexturedTriangle {
+
+ /**
+ * Scratch Point2D carriers for the flat paint call. Interpolators
+ * hold references to the screen/UV points they are given, so the
+ * objects must stay stable for the duration of one paint — but a
+ * paint never nests, so three screen + three UV points per thread
+ * suffice and nothing is allocated per triangle.
+ */
+ private static final ThreadLocal<Point2D[]> SCREEN_SCRATCH =
+ ThreadLocal.withInitial(() -> new Point2D[]{
+ new Point2D(), new Point2D(), new Point2D()});
+ private static final ThreadLocal<Point2D[]> UV_SCRATCH =
+ ThreadLocal.withInitial(() -> new Point2D[]{
+ new Point2D(), new Point2D(), new Point2D()});
+
+ private final TriangleMeshBlock block;
+ private final int index;
+
+ MeshTriangle(final TriangleMeshBlock block, final int index,
+ final eu.svjatoslav.aukio.e3d.renderer.raster.texture.Texture texture) {
+ super(texture);
+ this.block = block;
+ this.index = index;
+ }
+
+ /**
+ * No-op: the owning block transforms all its triangles (including this
+ * one) in a single flat-array loop. Queued handles are never
+ * transformed through the shape path. Sort Z and screen bounds live in
+ * the inherited per-slot fields, written by the block via
+ * {@code setSlotScreenState}.
+ */
+ @Override
+ public void transform(final TransformStack transforms,
+ final RenderAggregator aggregator,
+ final RenderingContext renderingContext) {
+ // intentionally empty — see TriangleMeshBlock.transform
+ }
+
+ /**
+ * Publishes this triangle's per-slot screen state (called by the
+ * owning block during its flat transform loop). Trampoline: the
+ * inherited setter is protected, so the call must go through the
+ * subclass.
+ */
+ void publishSlotState(final int slot, final double z,
+ final double minY, final double maxY,
+ final double minX, final double maxX) {
+ setSlotScreenState(slot, z, minY, maxY, minX, maxX);
+ }
+
+ @Override
+ public void paint(final RenderingContext renderBuffer) {
+ final int slot = renderBuffer.vertexSlot;
+ final Point2D[] screen = SCREEN_SCRATCH.get();
+ final Point2D[] uvs = UV_SCRATCH.get();
+
+ final int clip = block.clipOffset(slot, index);
+ if (clip >= 0) {
+ // Near-plane straddler: the block clipped to a loop of 3-4
+ // vertices, stored as (x, y, z, u, v, sx, sy) tuples. Paint
+ // as a fan, mirroring TexturedTriangle.paint's clipped path.
+ final int count = block.clipCount(slot, index);
+ final double[] store = block.clipStore(slot);
+ loadClipVertex(screen[0], uvs[0], store, clip);
+ for (int i = 1; i + 1 < count; i++) {
+ loadClipVertex(screen[1], uvs[1], store, clip + i * 7);
+ loadClipVertex(screen[2], uvs[2], store, clip + (i + 1) * 7);
+ // Fan sub-triangle screen perimeter — same expression as
+ // the object path (edge12 + edge13 + edge23); straddlers
+ // are rare, so it is computed here rather than stored.
+ final double dx01 = screen[0].x - screen[1].x;
+ final double dy01 = screen[0].y - screen[1].y;
+ final double dx02 = screen[0].x - screen[2].x;
+ final double dy02 = screen[0].y - screen[2].y;
+ final double dx12 = screen[1].x - screen[2].x;
+ final double dy12 = screen[1].y - screen[2].y;
+ final double visPerimeter = Math.sqrt(dx01 * dx01 + dy01 * dy01)
+ + Math.sqrt(dx02 * dx02 + dy02 * dy02)
+ + Math.sqrt(dx12 * dx12 + dy12 * dy12);
+ paintFlat(renderBuffer, block.texture(index), block.backfaceCull(),
+ screen[0], screen[1], screen[2],
+ uvs[0], uvs[1], uvs[2],
+ store[clip + 2],
+ store[clip + i * 7 + 2],
+ store[clip + (i + 1) * 7 + 2],
+ visPerimeter,
+ block.clipTtd(slot, clip));
+ }
+ return;
+ }
+
+ block.loadScreenVertex(screen[0], uvs[0], slot, index, 0, renderBuffer);
+ block.loadScreenVertex(screen[1], uvs[1], slot, index, 1, renderBuffer);
+ block.loadScreenVertex(screen[2], uvs[2], slot, index, 2, renderBuffer);
+ paintFlat(renderBuffer, block.texture(index), block.backfaceCull(),
+ screen[0], screen[1], screen[2],
+ uvs[0], uvs[1], uvs[2],
+ block.camZ(slot, index, 0),
+ block.camZ(slot, index, 1),
+ block.camZ(slot, index, 2),
+ block.screenPerim(slot, index),
+ block.uvPerimeter(index));
+ }
+
+ /**
+ * Fills the scratch screen/UV points from one clip-loop entry; screen
+ * coordinates were stored at clip time with the exact
+ * {@code Vertex.setCameraSpaceCoordinate} expression.
+ */
+ private void loadClipVertex(final Point2D screen, final Point2D uv,
+ final double[] store, final int entry) {
+ screen.x = store[entry + 5];
+ screen.y = store[entry + 6];
+ uv.x = store[entry + 3];
+ uv.y = store[entry + 4];
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.texturedpolygon;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point2D;
+
+import static java.lang.Math.round;
+
+/**
+ * Border interpolator carrying perspective-corrected texture gradients.
+ *
+ * <p>Quake-style perspective texturing: instead of interpolating texture
+ * coordinates (u, v) linearly in screen space (affine — wrong except for
+ * face-on triangles), interpolates (u/z, v/z, 1/z) which ARE linear in
+ * screen space. The scanline renderer recovers exact (u, v) with one
+ * reciprocal every N pixels and steps affinely in between, so the divide
+ * cost is amortized.</p>
+ *
+ * <p>The u/v values handed to this interpolator must already be premultiplied
+ * by the mipmap's multiplication factor and divided by the vertex's
+ * camera-space z; w values are 1/z.</p>
+ *
+ * @see PolygonBorderInterpolator
+ * @see TexturedTriangle
+ */
+public class PerspectiveBorderInterpolator {
+
+ /**
+ * Small epsilon value for comparing near-zero heights to detect horizontal edges.
+ */
+ private static final double EPSILON = 0.0001;
+
+ /** The first endpoint of this edge in screen space. */
+ private Point2D p1;
+ /** The second endpoint of this edge in screen space. */
+ private Point2D p2;
+
+ /** The vertical span (p2.y - p1.y) in double precision, may be negative. */
+ private double height;
+ /** The horizontal span (p2.x - p1.x) in double precision, may be negative. */
+ private double width;
+
+ /** u/z at the endpoints (mipmap factor premultiplied). */
+ private double su1, su2;
+ /** v/z at the endpoints (mipmap factor premultiplied). */
+ private double sv1, sv2;
+ /** 1/z at the endpoints. */
+ private double sw1, sw2;
+
+ /** Spans along the edge. */
+ private double suSpan, svSpan, swSpan;
+
+ /**
+ * Biased 1/z (the depth-buffer quantity) at the endpoints. Linear in
+ * screen space exactly like sw, so it rides the same edge
+ * interpolation; set only in z-buffer mode via {@link #setPointsZW}.
+ */
+ private double zw1, zw2;
+ private double zwSpan;
+
+ /** The current Y coordinate being interpolated. */
+ private int currentY;
+
+ /**
+ * Sets the screen endpoints and perspective-corrected gradients for this edge.
+ *
+ * @param screenPoint1 the first screen-space endpoint
+ * @param screenPoint2 the second screen-space endpoint
+ * @param su1 u/z at the first endpoint (mipmap factor premultiplied)
+ * @param sv1 v/z at the first endpoint (mipmap factor premultiplied)
+ * @param sw1 1/z at the first endpoint
+ * @param su2 u/z at the second endpoint
+ * @param sv2 v/z at the second endpoint
+ * @param sw2 1/z at the second endpoint
+ */
+ public void setPoints(final Point2D screenPoint1, final Point2D screenPoint2,
+ final double su1, final double sv1, final double sw1,
+ final double su2, final double sv2, final double sw2) {
+ this.p1 = screenPoint1;
+ this.p2 = screenPoint2;
+ this.su1 = su1;
+ this.sv1 = sv1;
+ this.sw1 = sw1;
+ this.su2 = su2;
+ this.sv2 = sv2;
+ this.sw2 = sw2;
+
+ height = p2.y - p1.y;
+ width = p2.x - p1.x;
+
+ suSpan = su2 - su1;
+ svSpan = sv2 - sv1;
+ swSpan = sw2 - sw1;
+ }
+
+ /**
+ * Tests whether the given y coordinate falls within the vertical span of this edge.
+ */
+ public boolean containsY(final int y) {
+ final double minY = Math.min(p1.y, p2.y);
+ final double maxY = Math.max(p1.y, p2.y);
+ return y >= minY && y <= maxY;
+ }
+
+ private double interpolationT() {
+ return (currentY - p1.y) / height;
+ }
+
+ /** Returns interpolated u/z at the current Y. */
+ public double getSU() {
+ if (Math.abs(height) < EPSILON)
+ return (su1 + su2) / 2d;
+ return su1 + interpolationT() * suSpan;
+ }
+
+ /** Returns interpolated v/z at the current Y. */
+ public double getSV() {
+ if (Math.abs(height) < EPSILON)
+ return (sv1 + sv2) / 2d;
+ return sv1 + interpolationT() * svSpan;
+ }
+
+ /** Returns interpolated 1/z at the current Y. */
+ public double getSW() {
+ if (Math.abs(height) < EPSILON)
+ return (sw1 + sw2) / 2d;
+ return sw1 + interpolationT() * swSpan;
+ }
+
+ /**
+ * Sets the depth-buffer endpoint values (biased 1/z) for this edge.
+ * Companion to {@link #setPoints}: kept separate so the classic
+ * painter path never pays for the extra channel.
+ */
+ public void setPointsZW(final double zw1, final double zw2) {
+ this.zw1 = zw1;
+ this.zw2 = zw2;
+ zwSpan = zw2 - zw1;
+ }
+
+ /** Returns interpolated biased 1/z (depth value) at the current Y. */
+ public double getZW() {
+ if (Math.abs(height) < EPSILON)
+ return (zw1 + zw2) / 2d;
+ return zw1 + interpolationT() * zwSpan;
+ }
+
+ /**
+ * Computes the interpolated x coordinate rounded to the nearest integer.
+ * Identical semantics to {@link PolygonBorderInterpolator#getX()}.
+ */
+ public int getX() {
+ if (Math.abs(height) < EPSILON)
+ return (int) round((p1.x + p2.x) / 2);
+ return (int) round(p1.x + (width * (currentY - p1.y)) / height);
+ }
+
+ /** Sets the current Y coordinate for interpolation. */
+ public void setCurrentY(final int y) {
+ this.currentY = y;
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.texturedpolygon;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point2D;
+
+import static java.lang.Math.round;
+
+/**
+ * Interpolator for textured polygon edges with perspective correction.
+ *
+ * <p>Maps screen coordinates to texture coordinates while maintaining
+ * perspective accuracy. Uses double-precision arithmetic to eliminate
+ * T-junction gaps from truncation errors, matching {@code LineInterpolator}
+ * behavior in the solid polygon renderer.</p>
+ *
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon.LineInterpolator
+ */
+public class PolygonBorderInterpolator {
+
+ /**
+ * Small epsilon value for comparing near-zero heights to detect horizontal edges.
+ */
+ private static final double EPSILON = 0.0001;
+
+ /**
+ * The first endpoint of this edge in screen space.
+ */
+ Point2D p1;
+ /**
+ * The second endpoint of this edge in screen space.
+ */
+ Point2D p2;
+
+ /**
+ * The vertical span (p2.y - p1.y) in double precision, which may be negative.
+ *
+ * <p>Stored as double to preserve subpixel precision during interpolation,
+ * eliminating rounding errors that cause T-junction gaps.</p>
+ */
+ private double height;
+ /**
+ * The horizontal span (p2.x - p1.x) in double precision, which may be negative.
+ */
+ private double width;
+
+ /**
+ * The texture coordinate at the first endpoint.
+ */
+ private Point2D texturePoint1;
+ /**
+ * The texture coordinate at the second endpoint.
+ */
+ private Point2D texturePoint2;
+ /**
+ * The texture U span (texturePoint2.x - texturePoint1.x).
+ */
+ private double textureWidth;
+ /**
+ * The texture V span (texturePoint2.y - texturePoint1.y).
+ */
+ private double textureHeight;
+
+ /**
+ * The current Y coordinate being interpolated, used for computing texture coordinates.
+ */
+ private int currentY;
+
+ /**
+ * Creates a new polygon border interpolator.
+ */
+ public PolygonBorderInterpolator() {
+ }
+
+ /**
+ * Tests whether the given y coordinate falls within the vertical span of this edge.
+ *
+ * <p>Uses double-precision comparison to handle subpixel vertex positions correctly.</p>
+ *
+ * @param y the scanline y coordinate to test
+ * @return {@code true} if {@code y} is between the y coordinates of the two endpoints (inclusive)
+ */
+ public boolean containsY(final int y) {
+ final double minY = Math.min(p1.y, p2.y);
+ final double maxY = Math.max(p1.y, p2.y);
+ return y >= minY && y <= maxY;
+ }
+
+ /**
+ * Returns the interpolated texture X coordinate at the current Y position.
+ *
+ * <p>For horizontal edges (height near zero), returns the midpoint texture X.</p>
+ *
+ * @return the texture X coordinate
+ */
+ public double getTX() {
+ if (Math.abs(height) < EPSILON) {
+ return (texturePoint1.x + texturePoint2.x) / 2d;
+ }
+ final double t = (currentY - p1.y) / height;
+ return texturePoint1.x + t * textureWidth;
+ }
+
+ /**
+ * Returns the interpolated texture Y coordinate at the current Y position.
+ *
+ * <p>For horizontal edges (height near zero), returns the midpoint texture Y.</p>
+ *
+ * @return the texture Y coordinate
+ */
+ public double getTY() {
+ if (Math.abs(height) < EPSILON) {
+ return (texturePoint1.y + texturePoint2.y) / 2d;
+ }
+ final double t = (currentY - p1.y) / height;
+ return texturePoint1.y + t * textureHeight;
+ }
+
+ /**
+ * Computes the interpolated x coordinate rounded to the nearest integer.
+ *
+ * <p>For horizontal edges (height near zero), returns the midpoint x value
+ * to avoid division by zero.</p>
+ *
+ * @return the interpolated x coordinate rounded to the nearest integer
+ */
+ public int getX() {
+ if (Math.abs(height) < EPSILON) {
+ return (int) round((p1.x + p2.x) / 2);
+ }
+ return (int) round(p1.x + (width * (currentY - p1.y)) / height);
+ }
+
+ /**
+ * Sets the current Y coordinate for interpolation.
+ *
+ * @param y the current Y coordinate
+ */
+ public void setCurrentY(final int y) {
+ this.currentY = y;
+ }
+
+ /**
+ * Sets the screen and texture coordinates for this edge.
+ *
+ * <p>Screen coordinates are stored directly as references. Callers should
+ * ensure coordinates are not modified during rendering for thread safety.</p>
+ *
+ * @param screenPoint1 the first screen-space endpoint
+ * @param screenPoint2 the second screen-space endpoint
+ * @param texturePoint1 the texture coordinate for the first endpoint
+ * @param texturePoint2 the texture coordinate for the second endpoint
+ */
+ public void setPoints(final Point2D screenPoint1, final Point2D screenPoint2,
+ final Point2D texturePoint1, final Point2D texturePoint2) {
+
+ this.p1 = screenPoint1;
+ this.p2 = screenPoint2;
+ this.texturePoint1 = texturePoint1;
+ this.texturePoint2 = texturePoint2;
+
+ height = p2.y - p1.y;
+ width = p2.x - p1.x;
+
+ textureWidth = texturePoint2.x - texturePoint1.x;
+ textureHeight = texturePoint2.y - texturePoint1.y;
+ }
+
+ /**
+ * Biased 1/z (the depth-buffer quantity) at the endpoints; set only
+ * in z-buffer mode via {@link #setPointsZW}. Interpolated linearly
+ * along the edge like the texture coordinates.
+ */
+ private double zw1, zw2, zwSpan;
+
+ /**
+ * Sets the depth-buffer endpoint values (biased 1/z) for this edge.
+ * Companion to {@link #setPoints}.
+ */
+ public void setPointsZW(final double zw1, final double zw2) {
+ this.zw1 = zw1;
+ this.zw2 = zw2;
+ zwSpan = zw2 - zw1;
+ }
+
+ /** Returns interpolated biased 1/z (depth value) at the current Y. */
+ public double getZW() {
+ if (Math.abs(height) < EPSILON)
+ return (zw1 + zw2) / 2d;
+ final double t = (currentY - p1.y) / height;
+ return zw1 + t * zwSpan;
+ }
+
+}
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.texturedpolygon;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point2D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.RenderingContext;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Vertex;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.AbstractCoordinateShape;
+import eu.svjatoslav.aukio.e3d.renderer.raster.texture.Texture;
+import eu.svjatoslav.aukio.e3d.renderer.raster.texture.TextureBitmap;
+
+import java.awt.*;
+import java.util.List;
+
+import static eu.svjatoslav.aukio.e3d.geometry.Polygon.pointWithinPolygon;
+
+/**
+ * A textured triangle renderer with perspective-correct texture mapping.
+ *
+ * <p>Quake-style subdivided perspective correction: (u/z, v/z, 1/z) are
+ * interpolated linearly in screen space and the exact texture coordinate
+ * is recovered with one reciprocal per subdivision interval, with affine
+ * stepping in between. This makes screen-size tessellation unnecessary —
+ * triangles of any size render with correct perspective.</p>
+ *
+ * @see Texture
+ * @see Vertex#textureCoordinate
+ */
+public class TexturedTriangle extends AbstractCoordinateShape {
+
+ private static final ThreadLocal<PolygonBorderInterpolator[]> INTERPOLATORS =
+ ThreadLocal.withInitial(() -> new PolygonBorderInterpolator[]{
+ new PolygonBorderInterpolator(), new PolygonBorderInterpolator(), new PolygonBorderInterpolator()
+ });
+
+ private static final ThreadLocal<PerspectiveBorderInterpolator[]> PERSPECTIVE_INTERPOLATORS =
+ ThreadLocal.withInitial(() -> new PerspectiveBorderInterpolator[]{
+ new PerspectiveBorderInterpolator(), new PerspectiveBorderInterpolator(),
+ new PerspectiveBorderInterpolator()
+ });
+
+ /**
+ * Quake-style perspective correction interval: the exact texture
+ * coordinate (one reciprocal) is computed every this many pixels;
+ * between correction points the scanline steps affinely.
+ */
+ private static final int PERSPECTIVE_CORRECTION_INTERVAL = 16;
+
+ /**
+ * Minimum camera-space z for the perspective path. Triangles with any
+ * vertex closer than this fall back to the affine path (they straddle
+ * the near plane, where 1/z interpolation is invalid).
+ */
+ private static final double PERSPECTIVE_MIN_Z = 0.001;
+
+ /** A/B tuning knobs for the SDF path, see paintSdf. */
+ private static final double SDF_GAMMA =
+ Double.parseDouble(System.getProperty("e3d.sdf.gamma", "0"));
+ private static final double SDF_SHARPEN =
+ Double.parseDouble(System.getProperty("e3d.sdf.sharpen", "2"));
+ /** Debug: print SDF path decisions when they change. */
+ private static final boolean SDF_DEBUG = Boolean.getBoolean("e3d.sdf.debug");
+ private static boolean sdfDebugLastPerspective;
+ private static double sdfDebugLastFootY = -1;
+
+ /**
+ * When true (default), textured triangles render with Quake-style
+ * perspective-correct texture mapping.
+ * Volatile: consulted from parallel paint workers.
+ */
+ private static volatile boolean perspectiveCorrectionEnabled = true;
+
+ /**
+ * Enables or disables perspective-correct texture mapping.
+ * When disabled, rendering falls back to plain affine mapping, which
+ * visibly warps textures on large on-screen triangles at steep angles.
+ *
+ * @param enabled {@code true} for perspective-correct mapping
+ */
+ public static void setPerspectiveCorrectionEnabled(final boolean enabled) {
+ perspectiveCorrectionEnabled = enabled;
+ }
+
+ /**
+ * Returns whether perspective-correct texture mapping is enabled.
+ *
+ * @return {@code true} when perspective correction is active
+ */
+ public static boolean isPerspectiveCorrectionEnabled() {
+ return perspectiveCorrectionEnabled;
+ }
+
+ /**
+ * The texture to apply to this triangle.
+ * Volatile: the global illumination system swaps the premultiplied
+ * lightmap composite on GI threads while paint workers read it.
+ * Read once per paint call so a triangle never shows a half-updated
+ * texture.
+ */
+ private volatile Texture texture;
+
+ /**
+ * Returns the current texture.
+ *
+ * @return the texture
+ */
+ public Texture getTexture() {
+ return texture;
+ }
+
+ /**
+ * Atomically swaps the texture. Painters pick up the new texture at the
+ * next paint call; a triangle in flight finishes with the old one.
+ *
+ * @param texture the new texture
+ */
+ public void setTexture(final Texture texture) {
+ this.texture = texture;
+ }
+
+ private boolean backfaceCulling = Boolean.getBoolean("e3d.backface");
+
+ // --- ad-hoc frame profiling (-De3d.prof=true; dead code when off)
+ /** Master switch, constant-folded when false. */
+ private static final boolean PROF =
+ Boolean.getBoolean("e3d.prof");
+ /** paintTriangle invocations. */
+ public static final java.util.concurrent.atomic.AtomicLong
+ PROF_TRIS = new java.util.concurrent.atomic.AtomicLong();
+ /** Triangles facing away (engine winding convention). */
+ public static final java.util.concurrent.atomic.AtomicLong
+ PROF_BACKFACE = new java.util.concurrent.atomic.AtomicLong();
+ /** Triangles discarded by vertical render-bounds clamp. */
+ public static final java.util.concurrent.atomic.AtomicLong
+ PROF_OFFY = new java.util.concurrent.atomic.AtomicLong();
+ /** Triangles with screen bounding box below 2x2 pixels. */
+ public static final java.util.concurrent.atomic.AtomicLong
+ PROF_TINY = new java.util.concurrent.atomic.AtomicLong();
+ /** Scanline spans drawn. */
+ public static final java.util.concurrent.atomic.AtomicLong
+ PROF_SPANS = new java.util.concurrent.atomic.AtomicLong();
+ /** Pixel loop iterations across all spans. */
+ public static final java.util.concurrent.atomic.AtomicLong
+ PROF_PIXELS = new java.util.concurrent.atomic.AtomicLong();
+
+ /** Resets all profiling counters. */
+ public static void profReset() {
+ PROF_TRIS.set(0);
+ PROF_BACKFACE.set(0);
+ PROF_OFFY.set(0);
+ PROF_TINY.set(0);
+ PROF_SPANS.set(0);
+ PROF_PIXELS.set(0);
+ }
+
+ /**
+ * Total UV distance between all texture coordinate pairs.
+ * Computed at construction time to determine appropriate mipmap level.
+ */
+ private double totalTextureDistance;
+
+ /**
+ * Creates a textured triangle with the specified vertices and texture.
+ *
+ * @param p1 the first vertex (must have textureCoordinate set)
+ * @param p2 the second vertex (must have textureCoordinate set)
+ * @param p3 the third vertex (must have textureCoordinate set)
+ * @param texture the texture to apply
+ */
+ public TexturedTriangle(Vertex p1, Vertex p2, Vertex p3, final Texture texture) {
+
+ super(p1, p2, p3);
+ this.texture = texture;
+ computeTotalTextureDistance();
+ }
+
+ /**
+ * Constructor for flat-array-backed subclasses ({@code MeshTriangle})
+ * that carry no {@link Vertex} objects and paint exclusively through
+ * {@link #paintFlat}, which computes the mipmap metric inline.
+ * {@code totalTextureDistance} is set to a neutral 1 — never read on
+ * that path.
+ *
+ * @param texture the texture the subclass paints with
+ */
+ protected TexturedTriangle(final Texture texture) {
+ super(0);
+ this.texture = texture;
+ this.totalTextureDistance = 1;
+ }
+
+ /**
+ * Computes the total UV distance between all texture coordinate pairs.
+ * Used to determine appropriate mipmap level.
+ */
+ private void computeTotalTextureDistance() {
+ totalTextureDistance = vertices.get(0).textureCoordinate.getDistanceTo(vertices.get(1).textureCoordinate);
+ totalTextureDistance += vertices.get(0).textureCoordinate.getDistanceTo(vertices.get(2).textureCoordinate);
+ totalTextureDistance += vertices.get(1).textureCoordinate.getDistanceTo(vertices.get(2).textureCoordinate);
+ }
+
+ /**
+ * Recomputes the mipmap-selection metric after texture coordinates are
+ * replaced post-construction (used by generated-UV subclasses like
+ * lightmapped triangles).
+ */
+ protected final void refreshTextureDistance() {
+ computeTotalTextureDistance();
+ }
+
+ /**
+ * Z-buffer span writer: the biased 1/z endpoint values ride the
+ * interpolators' zw channel, and every pixel is depth-tested BEFORE
+ * the texture fetch — rejected pixels cost one float compare instead
+ * of a texel read. Opaque texels (alpha 255) write depth; blended
+ * texels write color only, so translucency never occludes.
+ * {@code renderBuffer.depth} is always allocated (the z-buffer path
+ * is the only renderer); requires {@code setPointsZW} called on both
+ * interpolators.
+ */
+ private void drawHorizontalLinePerspectiveZ(
+ final PerspectiveBorderInterpolator line1,
+ final PerspectiveBorderInterpolator line2,
+ final int y,
+ final RenderingContext renderBuffer,
+ final TextureBitmap textureBitmap) {
+
+ line1.setCurrentY(y);
+ line2.setCurrentY(y);
+
+ int x1 = line1.getX();
+ int x2 = line2.getX();
+
+ final double su1, sv1, sw1, zw1;
+ final double su2, sv2, sw2, zw2;
+
+ if (x1 <= x2) {
+ su1 = line1.getSU();
+ sv1 = line1.getSV();
+ sw1 = line1.getSW();
+ zw1 = line1.getZW();
+ su2 = line2.getSU();
+ sv2 = line2.getSV();
+ sw2 = line2.getSW();
+ zw2 = line2.getZW();
+ } else {
+ final int tmp = x1;
+ x1 = x2;
+ x2 = tmp;
+ su1 = line2.getSU();
+ sv1 = line2.getSV();
+ sw1 = line2.getSW();
+ zw1 = line2.getZW();
+ su2 = line1.getSU();
+ sv2 = line1.getSV();
+ sw2 = line1.getSW();
+ zw2 = line1.getZW();
+ }
+
+ final double realWidth = x2 - x1;
+ final double realX1 = x1;
+
+ if (x1 < renderBuffer.renderMinX)
+ x1 = renderBuffer.renderMinX;
+ if (x2 >= renderBuffer.renderMaxX)
+ x2 = renderBuffer.renderMaxX;
+
+ final int span = x2 - x1;
+ if (span <= 0)
+ return;
+
+ if (PROF) {
+ PROF_SPANS.incrementAndGet();
+ PROF_PIXELS.addAndGet(span);
+ }
+
+ int renderBufferOffset = (y * renderBuffer.width) + x1;
+
+ final double dsu = (su2 - su1) / realWidth;
+ final double dsv = (sv2 - sv1) / realWidth;
+ final double dsw = (sw2 - sw1) / realWidth;
+ final double dzw = (zw2 - zw1) / realWidth;
+
+ // Depth margin (polygon offset): fragments within dzMargin world
+ // units of the stored depth resolve coherently instead of
+ // z-fighting per pixel — near-coplanar surface pairs (kit-bashed
+ // wall pieces, draped decals, LOD shells). The queue is
+ // back-to-front (painter, Z descending), so WITHIN the window
+ // the LATER (nearer) writer must win: the test therefore rejects
+ // only fragments that are BEHIND the stored depth by more than
+ // the margin. (The previous "+margin" form made the FIRST —
+ // i.e. FARTHER — writer win the window, so dirt within margin
+ // below the road beat the pavement; combined with a per-span
+ // margin constant that inflates by (z_pixel/z_near)^2 down
+ // grazing spans, ground leaked through the road at near-horizon
+ // pitches. Fixed camera, view-dependent holes = impossible for
+ // a correct z-buffer.)
+ // The w-space margin is dz*w^2 evaluated PER PIXEL at the
+ // fragment's own depth.
+
+ double su = su1 + dsu * (x1 - realX1);
+ double sv = sv1 + dsv * (x1 - realX1);
+ double sw = sw1 + dsw * (x1 - realX1);
+ double zw = zw1 + dzw * (x1 - realX1);
+
+ final int[] texPixels = textureBitmap.pixels;
+ final int texW = textureBitmap.width;
+ final int texH = textureBitmap.height;
+ final int texWMinus1 = texW - 1;
+ final int texHMinus1 = texH - 1;
+ final int[] renderBufferPixels = renderBuffer.pixels;
+ final float[] depth = renderBuffer.depth;
+ // Alpha pass (depthPass 2): depth-test but never depth-write,
+ // so cutout foliage cannot occlude later fragments
+ final boolean writeDepth = renderBuffer.depthPass != 2;
+ // null texture (unit tests) = clamp
+ final boolean wrap = texture != null && texture.wrap;
+
+ // Adaptive-subdivision perspective ladder (Quake-style stepping)
+ final double ue1 = su1 / sw1;
+ final double ue2 = su2 / sw2;
+ final double ve1 = sv1 / sw1;
+ final double ve2 = sv2 / sw2;
+ final double wRatio = Math.max(sw1, sw2) / Math.min(sw1, sw2);
+ final double texelRate = Math.max(Math.abs(ue2 - ue1), Math.abs(ve2 - ve1))
+ / realWidth * wRatio;
+ final double k = Math.abs(dsw) / Math.min(sw1, sw2);
+ final double curvature = texelRate * k;
+ final int interval = curvature < 0.5 / (16 * 16) ? PERSPECTIVE_CORRECTION_INTERVAL
+ : curvature < 0.5 / (8 * 8) ? 8
+ : curvature < 0.5 / (4 * 4) ? 4
+ : curvature < 0.5 / (2 * 2) ? 2 : 1;
+ final double invInterval = 1d / interval;
+
+ int done = 0;
+ double invW = 1d / sw;
+ double tx = su * invW;
+ double ty = sv * invW;
+ while (done < span) {
+ final int block = Math.min(interval, span - done);
+
+ su += dsu * block;
+ sv += dsv * block;
+ sw += dsw * block;
+ final double invWNext = 1d / sw;
+ final double txNext = su * invWNext;
+ final double tyNext = sv * invWNext;
+
+ final double invBlock = block == interval ? invInterval : 1d / block;
+ final double txStep = (txNext - tx) * invBlock;
+ final double tyStep = (tyNext - ty) * invBlock;
+
+ for (int i = 0; i < block; i++) {
+ if (zw > depth[renderBufferOffset] - RenderingContext.DEPTH_MARGIN_DZ * zw * zw) {
+ int itx = (int) tx;
+ int ity = (int) ty;
+
+ if (wrap) {
+ itx = Math.floorMod(itx, texW);
+ ity = Math.floorMod(ity, texH);
+ } else {
+ if (itx < 0) itx = 0;
+ else if (itx > texWMinus1) itx = texWMinus1;
+
+ if (ity < 0) ity = 0;
+ else if (ity > texHMinus1) ity = texHMinus1;
+ }
+
+ final int srcPixel = texPixels[ity * texW + itx];
+ final int srcAlpha = (srcPixel >> 24) & 0xff;
+
+ if (srcAlpha == 255) {
+ renderBufferPixels[renderBufferOffset] = srcPixel;
+ if (writeDepth)
+ depth[renderBufferOffset] = (float) zw;
+ } else if (srcAlpha != 0) {
+ // Translucent: blend, but do NOT write depth —
+ // translucency must not occlude later fragments.
+ // Lerp form dest + ((a*(src-dest) - dest) >> 8):
+ // algebraically ((255-a)*dest + a*src) >> 8 — proven
+ // bit-identical to SolidPolygon's form for all
+ // inputs, so the two span writers blend the same.
+ final int destPixel = renderBufferPixels[renderBufferOffset];
+ final int destR = (destPixel >> 16) & 0xff;
+ final int destG = (destPixel >> 8) & 0xff;
+ final int destB = destPixel & 0xff;
+
+ final int r = destR + ((srcAlpha * (((srcPixel >> 16) & 0xff) - destR) - destR) >> 8);
+ final int g = destG + ((srcAlpha * (((srcPixel >> 8) & 0xff) - destG) - destG) >> 8);
+ final int b = destB + ((srcAlpha * ((srcPixel & 0xff) - destB) - destB) >> 8);
+
+ renderBufferPixels[renderBufferOffset] = (r << 16) | (g << 8) | b;
+ }
+ }
+
+ tx += txStep;
+ ty += tyStep;
+ zw += dzw;
+ renderBufferOffset++;
+ }
+
+ tx = txNext;
+ ty = tyNext;
+
+ done += block;
+ }
+ }
+
+ @Override
+ public void paint(final RenderingContext renderBuffer) {
+ // Near-plane clip output takes precedence: a straddling triangle
+ // clips to a triangle or a quad (one corner cut off). The quad is
+ // painted as a 2-triangle fan — the clip of a convex polygon stays
+ // convex, so fan triangulation is exact. Clipped vertices carry
+ // UVs interpolated in 3D at the cut, which is exactly what the
+ // perspective-correct path expects of a point on the edge.
+ final List<Vertex> clipped = clippedVertices(renderBuffer);
+ if (clipped == null) {
+ paintTriangle(renderBuffer, vertices.get(0), vertices.get(1), vertices.get(2));
+ return;
+ }
+ for (int i = 1; i + 1 < clipped.size(); i++) {
+ paintTriangle(renderBuffer, clipped.get(0), clipped.get(i), clipped.get(i + 1));
+ }
+ }
+
+ /**
+ * Renders one textured triangle defined by the given vertices (either
+ * the shape's own three, or a fan triple from the near-plane-clipped
+ * loop).
+ *
+ * <p>This method performs:</p>
+ * <ul>
+ * <li>Backface culling check (if enabled)</li>
+ * <li>Mouse interaction detection</li>
+ * <li>Mipmap level selection based on screen coverage</li>
+ * <li>Scanline rasterization with texture sampling</li>
+ * </ul>
+ *
+ * @param renderBuffer the rendering context containing the pixel buffer
+ * @param v1 the first triangle vertex
+ * @param v2 the second triangle vertex
+ * @param v3 the third triangle vertex
+ */
+ private void paintTriangle(final RenderingContext renderBuffer,
+ final Vertex v1, final Vertex v2, final Vertex v3) {
+
+ final Point2D projectedPoint1 = v1.onScreenCoordinate(renderBuffer);
+ final Point2D projectedPoint2 = v2.onScreenCoordinate(renderBuffer);
+ final Point2D projectedPoint3 = v3.onScreenCoordinate(renderBuffer);
+
+ if (mouseInteractionController != null)
+ if (renderBuffer.getMouseEvent() != null)
+ if (pointWithinPolygon(
+ renderBuffer.getMouseEvent().coordinate, projectedPoint1, projectedPoint2, projectedPoint3)) {
+ final double[] uv = textureCoordinateAt(
+ renderBuffer.getMouseEvent().coordinate,
+ projectedPoint1, projectedPoint2, projectedPoint3,
+ v1, v2, v3, renderBuffer);
+ renderBuffer.setCurrentObjectUnderMouseCursor(
+ mouseInteractionController, uv[0], uv[1]);
+ }
+
+ // Show polygon boundaries (for debugging)
+ if (renderBuffer.developerTools != null && renderBuffer.developerTools.showPolygonBorders)
+ showBorders(renderBuffer);
+
+ // Keep double precision to eliminate T-junction gaps from truncation errors
+ final double y1 = projectedPoint1.y;
+ final double y2 = projectedPoint2.y;
+ final double y3 = projectedPoint3.y;
+
+ // Find top-most point (use ceil to include all pixels triangle touches)
+ int yTop = (int) Math.ceil(Math.min(y1, Math.min(y2, y3)));
+ if (yTop < 0) yTop = 0;
+
+ // Find bottom-most point (use floor to include all pixels triangle touches)
+ int yBottom = (int) Math.floor(Math.max(y1, Math.max(y2, y3)));
+ if (yBottom >= renderBuffer.height) yBottom = renderBuffer.height - 1;
+
+ // Clamp to render Y bounds (use renderMaxY - 1 because loop is inclusive)
+ yTop = Math.max(yTop, renderBuffer.renderMinY);
+ yBottom = Math.min(yBottom, renderBuffer.renderMaxY - 1);
+ if (yTop > yBottom) {
+ if (PROF)
+ PROF_OFFY.incrementAndGet();
+ return;
+ }
+
+ // Snapshot the texture reference for the whole paint: the GI system
+ // may swap the composite lightmap on another thread mid-frame.
+ final Texture texture = this.texture;
+
+ final double edge12 = projectedPoint1.getDistanceTo(projectedPoint2);
+ final double edge13 = projectedPoint1.getDistanceTo(projectedPoint3);
+ final double edge23 = projectedPoint2.getDistanceTo(projectedPoint3);
+ final double totalVisibleDistance = edge12 + edge13 + edge23;
+
+ final double scaleFactor = (totalVisibleDistance / totalTextureDistance) * 1.2d;
+
+ // SDF text/vector-art path: coverage comes from the distance
+ // field, not from stored coverage, so the mipmap chain (which
+ // trades sharpness for alias-freedom) is bypassed entirely.
+ if (texture.isSdf()) {
+ paintSdf(yTop, yBottom, renderBuffer,
+ projectedPoint1, projectedPoint2, projectedPoint3, scaleFactor,
+ v1, v2, v3);
+ return;
+ }
+
+ paintFlat(renderBuffer, texture, backfaceCulling,
+ projectedPoint1, projectedPoint2, projectedPoint3,
+ v1.textureCoordinate, v2.textureCoordinate, v3.textureCoordinate,
+ v1.transformedCoordinate(renderBuffer).z,
+ v2.transformedCoordinate(renderBuffer).z,
+ v3.transformedCoordinate(renderBuffer).z,
+ totalVisibleDistance,
+ totalTextureDistance);
+ }
+
+ /**
+ * Shared rasterization core for one textured triangle whose vertices
+ * are already in screen space. Called both by the object-backed path
+ * ({@link #paintTriangle}) and by {@code TriangleMeshBlock} handles,
+ * whose vertex data lives in flat per-block arrays instead of
+ * {@link Vertex} objects — the math here is identical either way,
+ * keeping both paths bit-exact.
+ *
+ * <p>Mouse interaction and debug borders stay in the object path
+ * (mesh blocks do not support picking). SDF textures are rejected:
+ * mesh blocks never carry them (enforced at block build time).</p>
+ *
+ * @param renderBuffer the rendering context containing the pixel buffer
+ * @param texture the texture to sample
+ * @param backfaceCulling whether to cull counter-clockwise triangles
+ * @param projectedPoint1 screen-space vertex 1
+ * @param projectedPoint2 screen-space vertex 2
+ * @param projectedPoint3 screen-space vertex 3
+ * @param texturePoint1 UV (primary-texture pixels) of vertex 1
+ * @param texturePoint2 UV of vertex 2
+ * @param texturePoint3 UV of vertex 3
+ * @param z1 camera-space depth of vertex 1
+ * @param z2 camera-space depth of vertex 2
+ * @param z3 camera-space depth of vertex 3
+ * @param totalVisibleDistance screen-edge perimeter for mipmap
+ * selection, computed once per paint call
+ * (or once per slot for mesh blocks) —
+ * callers share it instead of the core
+ * recomputing per tile
+ * @param totalTextureDistance UV perimeter for mipmap selection. For a
+ * near-plane-clipped fan this is the
+ * ORIGINAL triangle's perimeter (the clip
+ * does not change the texture's texel
+ * density), matching the object path.
+ */
+ void paintFlat(final RenderingContext renderBuffer,
+ final Texture texture,
+ final boolean backfaceCulling,
+ final Point2D projectedPoint1,
+ final Point2D projectedPoint2,
+ final Point2D projectedPoint3,
+ final Point2D texturePoint1,
+ final Point2D texturePoint2,
+ final Point2D texturePoint3,
+ final double z1, final double z2, final double z3,
+ final double totalVisibleDistance,
+ final double totalTextureDistance) {
+
+ // Z-buffer two-pass classification: opaque-class triangles
+ // paint in pass 1 (depth test + write), alpha-class in pass 2
+ // (depth test, no write) — see RenderAggregator.paintSorted.
+ final boolean alphaClass = texture.isSdf() || texture.hasAlpha;
+ if ((renderBuffer.depthPass == 1) == alphaClass)
+ return;
+
+ if (PROF) {
+ PROF_TRIS.incrementAndGet();
+ if ((projectedPoint2.x - projectedPoint1.x)
+ * (projectedPoint3.y - projectedPoint1.y)
+ - (projectedPoint3.x - projectedPoint1.x)
+ * (projectedPoint2.y - projectedPoint1.y) >= 0)
+ PROF_BACKFACE.incrementAndGet();
+ final double bw = Math.max(projectedPoint1.x, Math.max(
+ projectedPoint2.x, projectedPoint3.x))
+ - Math.min(projectedPoint1.x, Math.min(
+ projectedPoint2.x, projectedPoint3.x));
+ final double bh = Math.max(projectedPoint1.y, Math.max(
+ projectedPoint2.y, projectedPoint3.y))
+ - Math.min(projectedPoint1.y, Math.min(
+ projectedPoint2.y, projectedPoint3.y));
+ if (bw * bh < 4)
+ PROF_TINY.incrementAndGet();
+ }
+
+ if (backfaceCulling) {
+ final double signedArea = (projectedPoint2.x - projectedPoint1.x)
+ * (projectedPoint3.y - projectedPoint1.y)
+ - (projectedPoint3.x - projectedPoint1.x)
+ * (projectedPoint2.y - projectedPoint1.y);
+ if (signedArea >= 0)
+ return;
+ }
+
+ // Keep double precision to eliminate T-junction gaps from truncation errors
+ final double y1 = projectedPoint1.y;
+ final double y2 = projectedPoint2.y;
+ final double y3 = projectedPoint3.y;
+
+ // Find top-most point (use ceil to include all pixels triangle touches)
+ int yTop = (int) Math.ceil(Math.min(y1, Math.min(y2, y3)));
+ if (yTop < 0) yTop = 0;
+
+ // Find bottom-most point (use floor to include all pixels triangle touches)
+ int yBottom = (int) Math.floor(Math.max(y1, Math.max(y2, y3)));
+ if (yBottom >= renderBuffer.height) yBottom = renderBuffer.height - 1;
+
+ // Clamp to render Y bounds (use renderMaxY - 1 because loop is inclusive)
+ yTop = Math.max(yTop, renderBuffer.renderMinY);
+ yBottom = Math.min(yBottom, renderBuffer.renderMaxY - 1);
+ if (yTop > yBottom) {
+ if (PROF)
+ PROF_OFFY.incrementAndGet();
+ return;
+ }
+
+ if (texture.isSdf())
+ throw new IllegalStateException(
+ "SDF textures are not supported in mesh blocks");
+
+ final double scaleFactor = (totalVisibleDistance / totalTextureDistance) * 1.2d;
+
+ final TextureBitmap mipmap = texture.getMipmapForScale(scaleFactor);
+
+ if (perspectiveCorrectionEnabled) {
+ if (z1 > PERSPECTIVE_MIN_Z && z2 > PERSPECTIVE_MIN_Z && z3 > PERSPECTIVE_MIN_Z) {
+ // Affine mapping is within half a texel of exact
+ // perspective for small or nearly-flat triangles, making
+ // the perspective setup pointless for them: the midpoint
+ // error of affine vs exact is ~= texelSpan*(zRatio-1)/4
+ // where texelSpan is the texture range (in selected-mip
+ // texels) the triangle covers — NOT its pixel size (a
+ // triangle can map many texels into few pixels; measured
+ // 2026-09-06: a 4px span with a 56-texel range deviated 3
+ // texels under the pixel-size rule). Distant clusters of
+ // small triangles render affine.
+ // Verified by TexturedTrianglePerspectiveTest#affineWithinHalfTexelBound.
+ final double mf0 = mipmap.multiplicationFactor;
+ final double tu1 = texturePoint1.x * mf0;
+ final double tv1 = texturePoint1.y * mf0;
+ final double tu2 = texturePoint2.x * mf0;
+ final double tv2 = texturePoint2.y * mf0;
+ final double tu3 = texturePoint3.x * mf0;
+ final double tv3 = texturePoint3.y * mf0;
+ final double texelSpan = Math.max(
+ Math.max(Math.abs(tu2 - tu1), Math.abs(tv2 - tv1)),
+ Math.max(
+ Math.max(Math.abs(tu3 - tu1), Math.abs(tv3 - tv1)),
+ Math.max(Math.abs(tu3 - tu2), Math.abs(tv3 - tv2))));
+ final double zMin = Math.min(z1, Math.min(z2, z3));
+ final double zMax = Math.max(z1, Math.max(z2, z3));
+ if (texelSpan * (zMax / zMin - 1d) < 2d) {
+ paintAffine(yTop, yBottom, mipmap, renderBuffer,
+ projectedPoint1, projectedPoint2, projectedPoint3,
+ texturePoint1, texturePoint2, texturePoint3,
+ z1, z2, z3);
+ return;
+ }
+
+ // Quake-style perspective-correct mapping: interpolate
+ // (u/z, v/z, 1/z), which are linear in screen space, and
+ // recover exact (u, v) every PERSPECTIVE_CORRECTION_INTERVAL
+ // pixels in the scanline. The mipmap multiplication factor
+ // is folded into the gradients here, so the scanline works
+ // directly in texture pixel units.
+ final double mf = mipmap.multiplicationFactor;
+
+ final double sw1 = 1d / z1;
+ final double sw2 = 1d / z2;
+ final double sw3 = 1d / z3;
+
+ final double su1 = texturePoint1.x * mf * sw1;
+ final double sv1 = texturePoint1.y * mf * sw1;
+ final double su2 = texturePoint2.x * mf * sw2;
+ final double sv2 = texturePoint2.y * mf * sw2;
+ final double su3 = texturePoint3.x * mf * sw3;
+ final double sv3 = texturePoint3.y * mf * sw3;
+
+ final PerspectiveBorderInterpolator[] pi = PERSPECTIVE_INTERPOLATORS.get();
+ pi[0].setPoints(projectedPoint1, projectedPoint2, su1, sv1, sw1, su2, sv2, sw2);
+ pi[1].setPoints(projectedPoint1, projectedPoint3, su1, sv1, sw1, su3, sv3, sw3);
+ pi[2].setPoints(projectedPoint2, projectedPoint3, su2, sv2, sw2, su3, sv3, sw3);
+
+ {
+ // 1/z rides the same edge interpolation; spans
+ // depth-test before texturing.
+ final double zw1 = 1d / z1;
+ final double zw2 = 1d / z2;
+ final double zw3 = 1d / z3;
+ pi[0].setPointsZW(zw1, zw2);
+ pi[1].setPointsZW(zw1, zw3);
+ pi[2].setPointsZW(zw2, zw3);
+ for (int y = yTop; y <= yBottom; y++) {
+ if (pi[0].containsY(y)) {
+ if (pi[1].containsY(y))
+ drawHorizontalLinePerspectiveZ(pi[0], pi[1], y, renderBuffer, mipmap);
+ else if (pi[2].containsY(y))
+ drawHorizontalLinePerspectiveZ(pi[0], pi[2], y, renderBuffer, mipmap);
+ } else if (pi[1].containsY(y)) {
+ if (pi[2].containsY(y))
+ drawHorizontalLinePerspectiveZ(pi[1], pi[2], y, renderBuffer, mipmap);
+ }
+ }
+ return;
+ }
+ }
+ }
+
+ paintAffine(yTop, yBottom, mipmap, renderBuffer,
+ projectedPoint1, projectedPoint2, projectedPoint3,
+ texturePoint1, texturePoint2, texturePoint3,
+ z1, z2, z3);
+ }
+
+ /**
+ * Computes the perspective-correct texture coordinate at a screen-space
+ * point known to lie inside the triangle.
+ *
+ * <p>Screen-space barycentric weights are divided by the camera-space z
+ * of each vertex and renormalized — the same (u/z, v/z, 1/z) math the
+ * perspective-correct scanline path uses — so the returned coordinate
+ * matches the texel that was actually painted at that pixel, even at
+ * steep viewing angles. Texture coordinates are in primary-texture
+ * pixels (no mipmap factor applied).</p>
+ *
+ * @return double[2] with {u, v} in primary-texture pixels
+ */
+ private static double[] textureCoordinateAt(final Point2D point,
+ final Point2D p1, final Point2D p2, final Point2D p3,
+ final Vertex v1, final Vertex v2, final Vertex v3,
+ final RenderingContext renderBuffer) {
+ final double denom = (p2.y - p3.y) * (p1.x - p3.x)
+ + (p3.x - p2.x) * (p1.y - p3.y);
+ if (Math.abs(denom) < 1e-9)
+ // degenerate on screen; the hit pixel is effectively a vertex
+ return new double[]{v1.textureCoordinate.x, v1.textureCoordinate.y};
+
+ double w1 = ((p2.y - p3.y) * (point.x - p3.x)
+ + (p3.x - p2.x) * (point.y - p3.y)) / denom;
+ double w2 = ((p3.y - p1.y) * (point.x - p3.x)
+ + (p1.x - p3.x) * (point.y - p3.y)) / denom;
+ double w3 = 1d - w1 - w2;
+
+ final double z1 = v1.transformedCoordinate(renderBuffer).z;
+ final double z2 = v2.transformedCoordinate(renderBuffer).z;
+ final double z3 = v3.transformedCoordinate(renderBuffer).z;
+
+ if (z1 > PERSPECTIVE_MIN_Z && z2 > PERSPECTIVE_MIN_Z
+ && z3 > PERSPECTIVE_MIN_Z) {
+ w1 /= z1;
+ w2 /= z2;
+ w3 /= z3;
+ final double sum = w1 + w2 + w3;
+ w1 /= sum;
+ w2 /= sum;
+ w3 /= sum;
+ }
+ // near-plane straddlers: plain screen-space barycentric (affine),
+ // matching the affine fallback path used for painting them
+
+ return new double[]{
+ w1 * v1.textureCoordinate.x + w2 * v2.textureCoordinate.x
+ + w3 * v3.textureCoordinate.x,
+ w1 * v1.textureCoordinate.y + w2 * v2.textureCoordinate.y
+ + w3 * v3.textureCoordinate.y};
+ }
+
+ /**
+ * SDF (signed distance field) rendering path. Coverage is not stored
+ * in the texture; it is re-derived per pixel from a smooth distance
+ * mask, so edges stay sharp at any magnification and fade to clean
+ * gray under minification. Layers: {@code texture.primaryBitmap} is
+ * the background color layer, {@code texture.sdfForeground} the ink
+ * color layer (both sampled nearest — they are flat per region),
+ * {@code texture.sdfMask} the distance field (sampled bilinear).
+ *
+ * <p>Minification is handled analytically: the coverage window is
+ * widened by the screen-space pixel footprint, which gives correct
+ * area coverage without a mipmap chain.</p>
+ *
+ * @param scaleFactor the same screen-pixels-per-texel estimate the
+ * mipmap selection uses (times 1.2)
+ */
+ private void paintSdf(final int yTop, final int yBottom,
+ final RenderingContext renderBuffer,
+ final Point2D projectedPoint1, final Point2D projectedPoint2,
+ final Point2D projectedPoint3, final double scaleFactor,
+ final Vertex v1, final Vertex v2, final Vertex v3) {
+ // SDF (text/decal) is alpha-class — it paints in the
+ // back-to-front alpha pass only, without depth interaction.
+ if (renderBuffer.depthPass == 1)
+ return;
+ // Per-axis screen-space UV gradients (affine estimate — adequate
+ // for a footprint). Text on an angled plane is minified mostly
+ // along ONE axis; an isotropic average would blur the axis that
+ // still has resolution to spare.
+ double footX;
+ double footY;
+ final double ex = projectedPoint2.x - projectedPoint1.x;
+ final double ey = projectedPoint2.y - projectedPoint1.y;
+ final double fx3 = projectedPoint3.x - projectedPoint1.x;
+ final double fy3 = projectedPoint3.y - projectedPoint1.y;
+ final double denom = ex * fy3 - fx3 * ey;
+ if (Math.abs(denom) > 1e-9) {
+ final double u1 = v1.textureCoordinate.x;
+ final double vv1 = v1.textureCoordinate.y;
+ final double du21 = v2.textureCoordinate.x - u1;
+ final double dv21 = v2.textureCoordinate.y - vv1;
+ final double du31 = v3.textureCoordinate.x - u1;
+ final double dv31 = v3.textureCoordinate.y - vv1;
+ final double dudx = (du21 * fy3 - du31 * ey) / denom;
+ final double dudy = (du31 * ex - du21 * fx3) / denom;
+ final double dvdx = (dv21 * fy3 - dv31 * ey) / denom;
+ final double dvdy = (dv31 * ex - dv21 * fx3) / denom;
+ footX = Math.hypot(dudx, dvdx);
+ footY = Math.hypot(dudy, dvdy);
+ } else {
+ footX = footY = 1.2d / scaleFactor;
+ }
+
+ // The coverage window follows the SHARPEST axis: one screen pixel
+ // spans texelsPerPixel texels along it, i.e.
+ // texelsPerPixel/(2*spread) of the normalized mask range; aaK
+ // converts a mask sample (0..255, edge at 127.5) into fixed-point
+ // coverage in [0, 256]: cov = (127.5 - d)*aaK + 128.
+ final double maxFootprint = Math.max(footX, footY);
+ double texelsPerPixel = Math.max(Math.min(footX, footY), 0.01d);
+ if (maxFootprint > 1d) {
+ texelsPerPixel /= SDF_SHARPEN;
+ }
+ final double aaK = (2d * texture.sdfSpreadTexels) / texelsPerPixel / 255d * 256d;
+
+ // No mip chain for SDF layers. A distance field's edge gradient
+ // spans just 2 texels, so a half/quarter-res mask visibly melts
+ // glyph edges — and because the two triangles of a rectangle get
+ // slightly different perspective footprints, they crossed mip
+ // thresholds at different distances, producing a hard diagonal
+ // quality split plus sudden blur steps while dollying (observed
+ // 2026-09-06). Sampling the primary field costs some bandwidth
+ // under minification, but text surfaces are small and the
+ // per-pixel sample count is what matters. Quality then degrades
+ // smoothly with distance instead of in steps.
+ final TextureBitmap mask = texture.sdfMask;
+ final TextureBitmap fg = texture.sdfForeground;
+ final TextureBitmap bg = texture.primaryBitmap;
+ final double mf = mask.multiplicationFactor;
+
+ // Under minification, area-correct coverage reads as low-contrast
+ // gray haze. Two perceptual corrections (A/B-tuned 2026-09-06 on
+ // far+angled text): SDF_SHARPEN narrows the coverage window below
+ // one pixel (kills the haze halo, keeps edges crisp at the cost
+ // of a little shimmer), and a mild coverage gamma < 1 (stem
+ // darkening, the small-ppm font rasterizer trick) keeps thin
+ // strokes present.
+ // Knobs: -De3d.sdf.gamma=1.4 forces a fixed gamma (0 = auto),
+ // -De3d.sdf.sharpen=1 restores the pixel-exact window.
+ final int[] covLut;
+ final double gamma = SDF_GAMMA != 0 ? SDF_GAMMA
+ : Math.max(0.75d, 1d - 0.08d * (Math.log(maxFootprint) / Math.log(2d)));
+ if (gamma != 1d && maxFootprint > 1d) {
+ covLut = new int[257];
+ for (int i = 0; i <= 256; i++) {
+ covLut[i] = Math.min(256, (int) (256d * Math.pow(i / 256d, gamma)));
+ }
+ } else {
+ covLut = null;
+ }
+
+ boolean usePerspective = false;
+ double su1 = 0, sv1 = 0, sw1 = 0;
+ double su2 = 0, sv2 = 0, sw2 = 0;
+ double su3 = 0, sv3 = 0, sw3 = 0;
+ if (perspectiveCorrectionEnabled) {
+ final double z1 = v1.transformedCoordinate(renderBuffer).z;
+ final double z2 = v2.transformedCoordinate(renderBuffer).z;
+ final double z3 = v3.transformedCoordinate(renderBuffer).z;
+ if (z1 > PERSPECTIVE_MIN_Z && z2 > PERSPECTIVE_MIN_Z && z3 > PERSPECTIVE_MIN_Z) {
+ // Same affine-sufficiency test as the coverage path
+ // (mask/fg/bg are all primary resolution, mf = 1).
+ final double tu1 = v1.textureCoordinate.x;
+ final double tv1 = v1.textureCoordinate.y;
+ final double tu2 = v2.textureCoordinate.x;
+ final double tv2 = v2.textureCoordinate.y;
+ final double tu3 = v3.textureCoordinate.x;
+ final double tv3 = v3.textureCoordinate.y;
+ final double texelSpan = Math.max(
+ Math.max(Math.abs(tu2 - tu1), Math.abs(tv2 - tv1)),
+ Math.max(
+ Math.max(Math.abs(tu3 - tu1), Math.abs(tv3 - tv1)),
+ Math.max(Math.abs(tu3 - tu2), Math.abs(tv3 - tv2))));
+ final double zMin = Math.min(z1, Math.min(z2, z3));
+ final double zMax = Math.max(z1, Math.max(z2, z3));
+ usePerspective = texelSpan * (zMax / zMin - 1d) >= 2d;
+ if (usePerspective) {
+ sw1 = 1d / z1;
+ sw2 = 1d / z2;
+ sw3 = 1d / z3;
+ su1 = tu1 * mf * sw1;
+ sv1 = tv1 * mf * sw1;
+ su2 = tu2 * mf * sw2;
+ sv2 = tv2 * mf * sw2;
+ su3 = tu3 * mf * sw3;
+ sv3 = tv3 * mf * sw3;
+ }
+ }
+ }
+
+ if (SDF_DEBUG && (usePerspective != sdfDebugLastPerspective
+ || Math.abs(footY - sdfDebugLastFootY) > 0.5)) {
+ sdfDebugLastPerspective = usePerspective;
+ sdfDebugLastFootY = footY;
+ System.err.printf("[SDF] perspective=%b footX=%.2f footY=%.2f aaK=%.3f%n",
+ usePerspective, footX, footY, aaK);
+ }
+
+ if (usePerspective) {
+ final PerspectiveBorderInterpolator[] pi = PERSPECTIVE_INTERPOLATORS.get();
+ pi[0].setPoints(projectedPoint1, projectedPoint2, su1, sv1, sw1, su2, sv2, sw2);
+ pi[1].setPoints(projectedPoint1, projectedPoint3, su1, sv1, sw1, su3, sv3, sw3);
+ pi[2].setPoints(projectedPoint2, projectedPoint3, su2, sv2, sw2, su3, sv3, sw3);
+
+ for (int y = yTop; y <= yBottom; y++) {
+ if (pi[0].containsY(y)) {
+ if (pi[1].containsY(y))
+ drawHorizontalLinePerspectiveSdf(pi[0], pi[1], y, renderBuffer, mask, fg, bg, aaK, covLut);
+ else if (pi[2].containsY(y))
+ drawHorizontalLinePerspectiveSdf(pi[0], pi[2], y, renderBuffer, mask, fg, bg, aaK, covLut);
+ } else if (pi[1].containsY(y)) {
+ if (pi[2].containsY(y))
+ drawHorizontalLinePerspectiveSdf(pi[1], pi[2], y, renderBuffer, mask, fg, bg, aaK, covLut);
+ }
+ }
+ return;
+ }
+
+ final PolygonBorderInterpolator[] interpolators = INTERPOLATORS.get();
+ final PolygonBorderInterpolator pbi1 = interpolators[0];
+ final PolygonBorderInterpolator pbi2 = interpolators[1];
+ final PolygonBorderInterpolator pbi3 = interpolators[2];
+
+ pbi1.setPoints(projectedPoint1, projectedPoint2, v1.textureCoordinate, v2.textureCoordinate);
+ pbi2.setPoints(projectedPoint1, projectedPoint3, v1.textureCoordinate, v3.textureCoordinate);
+ pbi3.setPoints(projectedPoint2, projectedPoint3, v2.textureCoordinate, v3.textureCoordinate);
+
+ for (int y = yTop; y <= yBottom; y++) {
+ if (pbi1.containsY(y)) {
+ if (pbi2.containsY(y))
+ drawHorizontalLineSdf(pbi1, pbi2, y, renderBuffer, mask, fg, bg, aaK, mf, covLut);
+ else if (pbi3.containsY(y))
+ drawHorizontalLineSdf(pbi1, pbi3, y, renderBuffer, mask, fg, bg, aaK, mf, covLut);
+ } else if (pbi2.containsY(y)) {
+ if (pbi3.containsY(y))
+ drawHorizontalLineSdf(pbi2, pbi3, y, renderBuffer, mask, fg, bg, aaK, mf, covLut);
+ }
+ }
+ }
+
+ /**
+ * SDF scanline, affine mapping. Texture coordinates are scaled by the
+ * selected mip's multiplication factor (all layers share one mip
+ * level, so one factor covers mask and both color layers).
+ */
+ private void drawHorizontalLineSdf(final PolygonBorderInterpolator line1,
+ final PolygonBorderInterpolator line2, final int y,
+ final RenderingContext renderBuffer,
+ final TextureBitmap mask, final TextureBitmap fg,
+ final TextureBitmap bg, final double aaK,
+ final double mf, final int[] covLut) {
+ line1.setCurrentY(y);
+ line2.setCurrentY(y);
+
+ int x1 = line1.getX();
+ int x2 = line2.getX();
+
+ final double tx1, ty1, tx2, ty2;
+ if (x1 <= x2) {
+ tx1 = line1.getTX() * mf;
+ ty1 = line1.getTY() * mf;
+ tx2 = line2.getTX() * mf;
+ ty2 = line2.getTY() * mf;
+ } else {
+ final int tmp = x1;
+ x1 = x2;
+ x2 = tmp;
+ tx1 = line2.getTX() * mf;
+ ty1 = line2.getTY() * mf;
+ tx2 = line1.getTX() * mf;
+ ty2 = line1.getTY() * mf;
+ }
+
+ final double realWidth = x2 - x1;
+ final double realX1 = x1;
+
+ if (x1 < renderBuffer.renderMinX)
+ x1 = renderBuffer.renderMinX;
+ if (x2 >= renderBuffer.renderMaxX)
+ x2 = renderBuffer.renderMaxX;
+
+ int renderBufferOffset = (y * renderBuffer.width) + x1;
+ final int[] renderBufferPixels = renderBuffer.pixels;
+
+ final double txStep = (tx2 - tx1) / realWidth;
+ final double tyStep = (ty2 - ty1) / realWidth;
+
+ double tx = tx1 + txStep * (x1 - realX1);
+ double ty = ty1 + tyStep * (x1 - realX1);
+
+ final int[] maskPixels = mask.pixels;
+ final int[] fgPixels = fg.pixels;
+ final int[] bgPixels = bg.pixels;
+ final int mw = mask.width;
+ final int mh = mask.height;
+ final double bilinearCapX = mw - 1.0001d;
+ final double bilinearCapY = mh - 1.0001d;
+ final int mw1 = mw - 1;
+ final int mh1 = mh - 1;
+
+ for (int x = x1; x < x2; x++) {
+ // Fixed-point bilinear distance fetch (8.8 fractions)
+ final double ctx = tx < 0 ? 0 : Math.min(tx, bilinearCapX);
+ final double cty = ty < 0 ? 0 : Math.min(ty, bilinearCapY);
+ final int x0 = (int) ctx;
+ final int y0 = (int) cty;
+ final int fx = (int) ((ctx - x0) * 256);
+ final int fy = (int) ((cty - y0) * 256);
+ final int row0 = y0 * mw + x0;
+ final int row1 = row0 + mw;
+ final int m00 = (maskPixels[row0] >> 16) & 0xff;
+ final int m10 = (maskPixels[row0 + 1] >> 16) & 0xff;
+ final int m01 = (maskPixels[row1] >> 16) & 0xff;
+ final int m11 = (maskPixels[row1 + 1] >> 16) & 0xff;
+ final int d = (m00 * (256 - fx) * (256 - fy) + m10 * fx * (256 - fy)
+ + m01 * (256 - fx) * fy + m11 * fx * fy) >> 16;
+
+ int cov = (int) ((127.5d - d) * aaK + 128d);
+ if (cov < 0) cov = 0;
+ else if (cov > 256) cov = 256;
+ if (covLut != null) cov = covLut[cov];
+
+ int itx = (int) tx;
+ int ity = (int) ty;
+ if (itx < 0) itx = 0;
+ else if (itx > mw1) itx = mw1;
+ if (ity < 0) ity = 0;
+ else if (ity > mh1) ity = mh1;
+ final int addr = ity * mw + itx;
+
+ final int srcPixel;
+ if (cov <= 0) {
+ srcPixel = bgPixels[addr];
+ } else if (cov >= 256) {
+ srcPixel = fgPixels[addr];
+ } else {
+ final int bgP = bgPixels[addr];
+ final int fgP = fgPixels[addr];
+ final int a = (bgP >>> 24) + ((((int) (fgP >>> 24) - (bgP >>> 24)) * cov) >> 8);
+ final int r = ((bgP >> 16) & 0xff) + (((((fgP >> 16) & 0xff) - ((bgP >> 16) & 0xff)) * cov) >> 8);
+ final int g = ((bgP >> 8) & 0xff) + (((((fgP >> 8) & 0xff) - ((bgP >> 8) & 0xff)) * cov) >> 8);
+ final int b = (bgP & 0xff) + ((((fgP & 0xff) - (bgP & 0xff)) * cov) >> 8);
+ srcPixel = (a << 24) | (r << 16) | (g << 8) | b;
+ }
+
+ final int srcAlpha = (srcPixel >> 24) & 0xff;
+ if (srcAlpha == 255) {
+ renderBufferPixels[renderBufferOffset] = srcPixel;
+ } else if (srcAlpha != 0) {
+ final int destPixel = renderBufferPixels[renderBufferOffset];
+ final int destR = (destPixel >> 16) & 0xff;
+ final int destG = (destPixel >> 8) & 0xff;
+ final int destB = destPixel & 0xff;
+ final int r = destR + ((srcAlpha * (((srcPixel >> 16) & 0xff) - destR) - destR) >> 8);
+ final int g = destG + ((srcAlpha * (((srcPixel >> 8) & 0xff) - destG) - destG) >> 8);
+ final int b = destB + ((srcAlpha * ((srcPixel & 0xff) - destB) - destB) >> 8);
+ renderBufferPixels[renderBufferOffset] = (r << 16) | (g << 8) | b;
+ }
+
+ tx += txStep;
+ ty += tyStep;
+ renderBufferOffset++;
+ }
+ }
+
+ /**
+ * SDF scanline with Quake-style subdivided perspective correction —
+ * same stepping structure as {@link #drawHorizontalLinePerspectiveZ},
+ * with the coverage fetch replaced by the distance-field evaluation.
+ */
+ private void drawHorizontalLinePerspectiveSdf(
+ final PerspectiveBorderInterpolator line1,
+ final PerspectiveBorderInterpolator line2,
+ final int y,
+ final RenderingContext renderBuffer,
+ final TextureBitmap mask, final TextureBitmap fg,
+ final TextureBitmap bg, final double aaK, final int[] covLut) {
+
+ line1.setCurrentY(y);
+ line2.setCurrentY(y);
+
+ int x1 = line1.getX();
+ int x2 = line2.getX();
+
+ final double su1, sv1, sw1;
+ final double su2, sv2, sw2;
+
+ if (x1 <= x2) {
+ su1 = line1.getSU();
+ sv1 = line1.getSV();
+ sw1 = line1.getSW();
+ su2 = line2.getSU();
+ sv2 = line2.getSV();
+ sw2 = line2.getSW();
+ } else {
+ final int tmp = x1;
+ x1 = x2;
+ x2 = tmp;
+ su1 = line2.getSU();
+ sv1 = line2.getSV();
+ sw1 = line2.getSW();
+ su2 = line1.getSU();
+ sv2 = line1.getSV();
+ sw2 = line1.getSW();
+ }
+
+ final double realWidth = x2 - x1;
+ final double realX1 = x1;
+
+ if (x1 < renderBuffer.renderMinX)
+ x1 = renderBuffer.renderMinX;
+ if (x2 >= renderBuffer.renderMaxX)
+ x2 = renderBuffer.renderMaxX;
+
+ final int span = x2 - x1;
+ if (span <= 0)
+ return;
+
+ int renderBufferOffset = (y * renderBuffer.width) + x1;
+
+ final double dsu = (su2 - su1) / realWidth;
+ final double dsv = (sv2 - sv1) / realWidth;
+ final double dsw = (sw2 - sw1) / realWidth;
+
+ double su = su1 + dsu * (x1 - realX1);
+ double sv = sv1 + dsv * (x1 - realX1);
+ double sw = sw1 + dsw * (x1 - realX1);
+
+ final int[] renderBufferPixels = renderBuffer.pixels;
+
+ final int[] maskPixels = mask.pixels;
+ final int[] fgPixels = fg.pixels;
+ final int[] bgPixels = bg.pixels;
+ final int mw = mask.width;
+ final int mh = mask.height;
+ final double bilinearCapX = mw - 1.0001d;
+ final double bilinearCapY = mh - 1.0001d;
+ final int mw1 = mw - 1;
+ final int mh1 = mh - 1;
+
+ // Same adaptive-interval ladder as the coverage path.
+ final double ue1 = su1 / sw1;
+ final double ue2 = su2 / sw2;
+ final double ve1 = sv1 / sw1;
+ final double ve2 = sv2 / sw2;
+ final double wRatio = Math.max(sw1, sw2) / Math.min(sw1, sw2);
+ final double texelRate = Math.max(Math.abs(ue2 - ue1), Math.abs(ve2 - ve1))
+ / realWidth * wRatio;
+ final double k = Math.abs(dsw) / Math.min(sw1, sw2);
+ final double curvature = texelRate * k;
+ final int interval = curvature < 0.5 / (16 * 16) ? PERSPECTIVE_CORRECTION_INTERVAL
+ : curvature < 0.5 / (8 * 8) ? 8
+ : curvature < 0.5 / (4 * 4) ? 4
+ : curvature < 0.5 / (2 * 2) ? 2 : 1;
+ final double invInterval = 1d / interval;
+
+ int done = 0;
+ double invW = 1d / sw;
+ double tx = su * invW;
+ double ty = sv * invW;
+ while (done < span) {
+ final int block = Math.min(interval, span - done);
+
+ su += dsu * block;
+ sv += dsv * block;
+ sw += dsw * block;
+ final double invWNext = 1d / sw;
+ final double txNext = su * invWNext;
+ final double tyNext = sv * invWNext;
+
+ final double invBlock = block == interval ? invInterval : 1d / block;
+ final double txStep = (txNext - tx) * invBlock;
+ final double tyStep = (tyNext - ty) * invBlock;
+
+ for (int i = 0; i < block; i++) {
+ // Fixed-point bilinear distance fetch (8.8 fractions)
+ final double ctx = tx < 0 ? 0 : Math.min(tx, bilinearCapX);
+ final double cty = ty < 0 ? 0 : Math.min(ty, bilinearCapY);
+ final int x0 = (int) ctx;
+ final int y0 = (int) cty;
+ final int fx = (int) ((ctx - x0) * 256);
+ final int fy = (int) ((cty - y0) * 256);
+ final int row0 = y0 * mw + x0;
+ final int row1 = row0 + mw;
+ final int m00 = (maskPixels[row0] >> 16) & 0xff;
+ final int m10 = (maskPixels[row0 + 1] >> 16) & 0xff;
+ final int m01 = (maskPixels[row1] >> 16) & 0xff;
+ final int m11 = (maskPixels[row1 + 1] >> 16) & 0xff;
+ final int d = (m00 * (256 - fx) * (256 - fy) + m10 * fx * (256 - fy)
+ + m01 * (256 - fx) * fy + m11 * fx * fy) >> 16;
+
+ int cov = (int) ((127.5d - d) * aaK + 128d);
+ if (cov < 0) cov = 0;
+ else if (cov > 256) cov = 256;
+ if (covLut != null) cov = covLut[cov];
+
+ int itx = (int) tx;
+ int ity = (int) ty;
+ if (itx < 0) itx = 0;
+ else if (itx > mw1) itx = mw1;
+ if (ity < 0) ity = 0;
+ else if (ity > mh1) ity = mh1;
+ final int addr = ity * mw + itx;
+
+ final int srcPixel;
+ if (cov <= 0) {
+ srcPixel = bgPixels[addr];
+ } else if (cov >= 256) {
+ srcPixel = fgPixels[addr];
+ } else {
+ final int bgP = bgPixels[addr];
+ final int fgP = fgPixels[addr];
+ final int a = (bgP >>> 24) + ((((int) (fgP >>> 24) - (bgP >>> 24)) * cov) >> 8);
+ final int r = ((bgP >> 16) & 0xff) + (((((fgP >> 16) & 0xff) - ((bgP >> 16) & 0xff)) * cov) >> 8);
+ final int g = ((bgP >> 8) & 0xff) + (((((fgP >> 8) & 0xff) - ((bgP >> 8) & 0xff)) * cov) >> 8);
+ final int b = (bgP & 0xff) + ((((fgP & 0xff) - (bgP & 0xff)) * cov) >> 8);
+ srcPixel = (a << 24) | (r << 16) | (g << 8) | b;
+ }
+
+ final int srcAlpha = (srcPixel >> 24) & 0xff;
+ if (srcAlpha == 255) {
+ renderBufferPixels[renderBufferOffset] = srcPixel;
+ } else if (srcAlpha != 0) {
+ final int destPixel = renderBufferPixels[renderBufferOffset];
+ final int destR = (destPixel >> 16) & 0xff;
+ final int destG = (destPixel >> 8) & 0xff;
+ final int destB = destPixel & 0xff;
+ final int r = destR + ((srcAlpha * (((srcPixel >> 16) & 0xff) - destR) - destR) >> 8);
+ final int g = destG + ((srcAlpha * (((srcPixel >> 8) & 0xff) - destG) - destG) >> 8);
+ final int b = destB + ((srcAlpha * ((srcPixel & 0xff) - destB) - destB) >> 8);
+ renderBufferPixels[renderBufferOffset] = (r << 16) | (g << 8) | b;
+ }
+
+ tx += txStep;
+ ty += tyStep;
+ renderBufferOffset++;
+ }
+
+ done += block;
+ }
+ }
+
+ /**
+ * Affine texture mapping (u, v linear in screen space). Used for
+ * near-plane straddlers and for triangles small/flat enough that
+ * affine is within half a texel of exact perspective mapping.
+ */
+ private void paintAffine(final int yTop, final int yBottom,
+ final TextureBitmap mipmap,
+ final RenderingContext renderBuffer,
+ final Point2D projectedPoint1, final Point2D projectedPoint2,
+ final Point2D projectedPoint3,
+ final Point2D texturePoint1, final Point2D texturePoint2,
+ final Point2D texturePoint3,
+ final double z1, final double z2, final double z3) {
+ final PolygonBorderInterpolator[] interpolators = INTERPOLATORS.get();
+ final PolygonBorderInterpolator pbi1 = interpolators[0];
+ final PolygonBorderInterpolator pbi2 = interpolators[1];
+ final PolygonBorderInterpolator pbi3 = interpolators[2];
+
+ pbi1.setPoints(projectedPoint1, projectedPoint2, texturePoint1, texturePoint2);
+ pbi2.setPoints(projectedPoint1, projectedPoint3, texturePoint1, texturePoint3);
+ pbi3.setPoints(projectedPoint2, projectedPoint3, texturePoint2, texturePoint3);
+
+ final double zw1 = 1d / z1;
+ final double zw2 = 1d / z2;
+ final double zw3 = 1d / z3;
+ pbi1.setPointsZW(zw1, zw2);
+ pbi2.setPointsZW(zw1, zw3);
+ pbi3.setPointsZW(zw2, zw3);
+ for (int y = yTop; y <= yBottom; y++) {
+ if (pbi1.containsY(y)) {
+ if (pbi2.containsY(y))
+ drawHorizontalLineZ(pbi1, pbi2, y, renderBuffer, mipmap);
+ else if (pbi3.containsY(y))
+ drawHorizontalLineZ(pbi1, pbi3, y, renderBuffer, mipmap);
+ } else if (pbi2.containsY(y)) {
+ if (pbi3.containsY(y))
+ drawHorizontalLineZ(pbi2, pbi3, y, renderBuffer, mipmap);
+ }
+ }
+
+ }
+
+ /**
+ * Z-buffer span writer: per-pixel depth test (biased 1/z, linear
+ * along the span) BEFORE the texture fetch. Opaque texels write
+ * depth; blended texels write color only.
+ */
+ private void drawHorizontalLineZ(final PolygonBorderInterpolator line1,
+ final PolygonBorderInterpolator line2,
+ final int y,
+ final RenderingContext renderBuffer,
+ final TextureBitmap textureBitmap) {
+
+ line1.setCurrentY(y);
+ line2.setCurrentY(y);
+
+ int x1 = line1.getX();
+ int x2 = line2.getX();
+
+ final double tx1, ty1, zw1;
+ final double tx2, ty2, zw2;
+
+ if (x1 <= x2) {
+ tx1 = line1.getTX() * textureBitmap.multiplicationFactor;
+ ty1 = line1.getTY() * textureBitmap.multiplicationFactor;
+ zw1 = line1.getZW();
+ tx2 = line2.getTX() * textureBitmap.multiplicationFactor;
+ ty2 = line2.getTY() * textureBitmap.multiplicationFactor;
+ zw2 = line2.getZW();
+ } else {
+ final int tmp = x1;
+ x1 = x2;
+ x2 = tmp;
+
+ tx1 = line2.getTX() * textureBitmap.multiplicationFactor;
+ ty1 = line2.getTY() * textureBitmap.multiplicationFactor;
+ zw1 = line2.getZW();
+
+ tx2 = line1.getTX() * textureBitmap.multiplicationFactor;
+ ty2 = line1.getTY() * textureBitmap.multiplicationFactor;
+ zw2 = line1.getZW();
+ }
+
+ final double realWidth = x2 - x1;
+ final double realX1 = x1;
+
+ if (x1 < renderBuffer.renderMinX)
+ x1 = renderBuffer.renderMinX;
+
+ // x2 is exclusive: clamp to renderMaxX (see drawHorizontalLine)
+ if (x2 >= renderBuffer.renderMaxX)
+ x2 = renderBuffer.renderMaxX;
+
+ if (PROF) {
+ PROF_SPANS.incrementAndGet();
+ PROF_PIXELS.addAndGet(Math.max(0, x2 - x1));
+ }
+
+ int renderBufferOffset = (y * renderBuffer.width) + x1;
+ final int[] renderBufferPixels = renderBuffer.pixels;
+ final float[] depth = renderBuffer.depth;
+ // Alpha pass (depthPass 2): depth-test but never depth-write
+ final boolean writeDepth = renderBuffer.depthPass != 2;
+
+ final double txStep = (tx2 - tx1) / realWidth;
+ final double tyStep = (ty2 - ty1) / realWidth;
+ final double dzw = (zw2 - zw1) / realWidth;
+ double tx = tx1 + txStep * (x1 - realX1);
+ double ty = ty1 + tyStep * (x1 - realX1);
+ double zw = zw1 + dzw * (x1 - realX1);
+
+ final int[] texPixels = textureBitmap.pixels;
+ final int texW = textureBitmap.width;
+ final int texH = textureBitmap.height;
+ final int texWMinus1 = texW - 1;
+ final int texHMinus1 = texH - 1;
+ // texture is null in unit tests: clamp (see drawHorizontalLine)
+ final boolean wrap = texture != null && texture.wrap;
+
+ for (int x = x1; x < x2; x++) {
+
+ if (zw > depth[renderBufferOffset] - RenderingContext.DEPTH_MARGIN_DZ * zw * zw) {
+ int itx = (int) tx;
+ int ity = (int) ty;
+
+ if (wrap) {
+ itx = Math.floorMod(itx, texW);
+ ity = Math.floorMod(ity, texH);
+ } else {
+ if (itx < 0) itx = 0;
+ else if (itx > texWMinus1) itx = texWMinus1;
+
+ if (ity < 0) ity = 0;
+ else if (ity > texHMinus1) ity = texHMinus1;
+ }
+
+ final int srcPixel = texPixels[ity * texW + itx];
+ final int srcAlpha = (srcPixel >> 24) & 0xff;
+
+ if (srcAlpha == 255) {
+ renderBufferPixels[renderBufferOffset] = srcPixel;
+ if (writeDepth)
+ depth[renderBufferOffset] = (float) zw;
+ } else if (srcAlpha != 0) {
+ // Translucent: blend without writing depth
+ final int destPixel = renderBufferPixels[renderBufferOffset];
+ final int destR = (destPixel >> 16) & 0xff;
+ final int destG = (destPixel >> 8) & 0xff;
+ final int destB = destPixel & 0xff;
+
+ final int r = destR + ((srcAlpha * (((srcPixel >> 16) & 0xff) - destR) - destR) >> 8);
+ final int g = destG + ((srcAlpha * (((srcPixel >> 8) & 0xff) - destG) - destG) >> 8);
+ final int b = destB + ((srcAlpha * ((srcPixel & 0xff) - destB) - destB) >> 8);
+
+ renderBufferPixels[renderBufferOffset] = (r << 16) | (g << 8) | b;
+ }
+ }
+
+ tx += txStep;
+ ty += tyStep;
+ zw += dzw;
+ renderBufferOffset++;
+ }
+
+ }
+
+ /**
+ * Checks if backface culling is enabled for this triangle.
+ *
+ * @return {@code true} if backface culling is enabled
+ */
+ public boolean isBackfaceCullingEnabled() {
+ return backfaceCulling;
+ }
+
+ /**
+ * Enables or disables backface culling for this triangle.
+ *
+ * @param backfaceCulling {@code true} to enable backface culling
+ */
+ public void setBackfaceCulling(final boolean backfaceCulling) {
+ this.backfaceCulling = backfaceCulling;
+ }
+
+ /**
+ * Draws the triangle border edges in yellow (for debugging).
+ *
+ * @param renderBuffer the rendering context
+ */
+ private void showBorders(final RenderingContext renderBuffer) {
+
+ final Point2D projectedPoint1 = vertices.get(0).onScreenCoordinate(renderBuffer);
+ final Point2D projectedPoint2 = vertices.get(1).onScreenCoordinate(renderBuffer);
+ final Point2D projectedPoint3 = vertices.get(2).onScreenCoordinate(renderBuffer);
+
+ final int x1 = (int) projectedPoint1.x;
+ final int y1 = (int) projectedPoint1.y;
+ final int x2 = (int) projectedPoint2.x;
+ final int y2 = (int) projectedPoint2.y;
+ final int x3 = (int) projectedPoint3.x;
+ final int y3 = (int) projectedPoint3.y;
+
+ renderBuffer.executeWithGraphics(g -> {
+ g.setColor(Color.YELLOW);
+ g.drawLine(x1, y1, x2, y2);
+ g.drawLine(x3, y3, x2, y2);
+ g.drawLine(x1, y1, x3, y3);
+ });
+ }
+
+}
--- /dev/null
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.texturedpolygon;
+
+import eu.svjatoslav.aukio.e3d.geometry.Box;
+import eu.svjatoslav.aukio.e3d.geometry.Point2D;
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.HiZPyramid;
+import eu.svjatoslav.aukio.e3d.renderer.raster.RenderingContext;
+import eu.svjatoslav.aukio.e3d.renderer.raster.StereoEye;
+import eu.svjatoslav.aukio.e3d.renderer.raster.RenderAggregator;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.AbstractShape;
+import eu.svjatoslav.aukio.e3d.renderer.raster.texture.Texture;
+import eu.svjatoslav.aukio.e3d.math.TransformStack;
+
+/**
+ * A block of textured triangles stored as flat primitive arrays
+ * (struct-of-arrays) instead of one object graph per triangle. Built once
+ * (off the render thread), then every frame a single tight loop applies
+ * the composed camera transform to all vertices — sequential memory
+ * access instead of pointer chasing through {@code Vertex}/{@code Point3D}
+ * soup, which is what made the transform phase memory-latency-bound.
+ *
+ * <p>Interaction with the rest of the pipeline is unchanged: each visible
+ * triangle is queued as a thin preallocated {@link MeshTriangle} handle
+ * into the same {@link RenderAggregator}, sorted by the same comparator,
+ * binned into the same tile grid, and painted by the same
+ * {@link TexturedTriangle#paintFlat} core — bit-exact with the
+ * object-backed path.</p>
+ *
+ * <p>Subpixel-cull verdicts are cached per triangle ({@link #cullEpoch}):
+ * while the verdict epoch holds, a culled triangle costs one integer
+ * compare per frame — no vertex math at all.</p>
+ *
+ * <p>Limitations vs object-backed triangles: no mouse picking, no SDF
+ * textures (rejected at build), no GI/lightmap integration.</p>
+ */
+public final class TriangleMeshBlock extends AbstractShape {
+
+ // Build-time geometry: 9 world doubles and 6 UV doubles per triangle.
+ private final double[] world;
+ private final double[] uv;
+ private final Texture[] textures;
+ private final boolean backfaceCull;
+ private final int triCount;
+ private final MeshTriangle[] handles;
+ private final Box boundingBox;
+
+ // Per-slot projected state: 3 screen/camera doubles per triangle per
+ // slot. (Sort Z and binning bounds are published into the handles'
+ // per-slot fields at transform time, not kept here.)
+ private final double[][] projX = new double[3][];
+ private final double[][] projY = new double[3][];
+ private final double[][] camZ = new double[3][];
+
+ // Subpixel-cull verdicts: epoch in which the triangle was found tiny.
+ private final int[] cullEpoch;
+
+ // Near-plane clip output per slot: packed (offset << 3) | count into
+ // clipStore, -1 = not clipped. Clip data is 7 doubles per loop vertex
+ // (camera x, y, z, u, v + screen x, y), at most 4 vertices per
+ // straddler. Sort Z and binning bounds for straddlers are derived
+ // from the store, exactly like the object path derives them from the
+ // clipped loop. clipTtd keeps the ORIGINAL triangle's UV perimeter
+ // per straddler (index = clip offset / 28): mipmap selection must
+ // use the unclipped texel density, exactly like the object path.
+ private static final int CLIP_STRIDE = 7;
+ private static final int CLIP_ENTRY = 4 * CLIP_STRIDE;
+ private final int[][] clipRef = new int[3][];
+ private final double[][] clipStore = new double[3][];
+ private final double[][] clipTtd = new double[3][];
+
+ /** Per-triangle UV perimeter (mipmap metric), computed once at build:
+ * the uv array never changes afterwards. Same expression and
+ * accumulation order as {@code TexturedTriangle}'s
+ * computeTotalTextureDistance: d(0,1) + d(0,2) + d(1,2). */
+ private final double[] uvPerimeter;
+
+ /** Per-triangle screen-edge perimeter (mipmap metric's visible side),
+ * computed once per slot in the transform loop — identical expression
+ * to what the paint core used to recompute per tile. */
+ private final double[][] screenPerim = new double[3][];
+ private final int[] clipUsed = new int[3];
+
+ // Scratch for the composed top transform of the current transform call.
+ private final double[] top = new double[12];
+
+ /**
+ * Builds a block from baked world-space triangle soup.
+ *
+ * @param world 9 doubles per triangle (x0,y0,z0,x1,...), world
+ * space; the array is adopted, not copied
+ * @param uv 6 doubles per triangle (u0,v0,...) in primary
+ * texture pixels; adopted
+ * @param textures one texture per triangle
+ * @param backfaceCull cull clockwise triangles on screen
+ */
+ public TriangleMeshBlock(final double[] world, final double[] uv,
+ final Texture[] textures,
+ final boolean backfaceCull) {
+ this.triCount = textures.length;
+ if (world.length != triCount * 9 || uv.length != triCount * 6)
+ throw new IllegalArgumentException("array length mismatch");
+ this.world = world;
+ this.uv = uv;
+ this.textures = textures;
+ this.backfaceCull = backfaceCull;
+ for (final Texture texture : textures)
+ if (texture != null && texture.isSdf())
+ throw new IllegalArgumentException(
+ "SDF textures are not supported in mesh blocks");
+
+ this.handles = new MeshTriangle[triCount];
+ for (int t = 0; t < triCount; t++)
+ handles[t] = new MeshTriangle(this, t, textures[t]);
+
+ this.cullEpoch = new int[triCount];
+ java.util.Arrays.fill(cullEpoch, -1);
+
+ for (int s = 0; s < 3; s++) {
+ projX[s] = new double[triCount * 3];
+ projY[s] = new double[triCount * 3];
+ camZ[s] = new double[triCount * 3];
+ clipRef[s] = new int[triCount];
+ java.util.Arrays.fill(clipRef[s], -1);
+ clipStore[s] = new double[256];
+ clipTtd[s] = new double[16];
+ screenPerim[s] = new double[triCount];
+ }
+
+ uvPerimeter = new double[triCount];
+ for (int t = 0; t < triCount; t++) {
+ final int u = t * 6;
+ final double d1 = Math.sqrt(
+ ((uv[u] - uv[u + 2]) * (uv[u] - uv[u + 2]))
+ + ((uv[u + 1] - uv[u + 3]) * (uv[u + 1] - uv[u + 3])));
+ final double d2 = Math.sqrt(
+ ((uv[u] - uv[u + 4]) * (uv[u] - uv[u + 4]))
+ + ((uv[u + 1] - uv[u + 5]) * (uv[u + 1] - uv[u + 5])));
+ final double d3 = Math.sqrt(
+ ((uv[u + 2] - uv[u + 4]) * (uv[u + 2] - uv[u + 4]))
+ + ((uv[u + 3] - uv[u + 5]) * (uv[u + 3] - uv[u + 5])));
+ uvPerimeter[t] = d1 + d2 + d3;
+ }
+
+ double minX = Double.MAX_VALUE, minY = Double.MAX_VALUE,
+ minZ = Double.MAX_VALUE;
+ double maxX = -Double.MAX_VALUE, maxY = -Double.MAX_VALUE,
+ maxZ = -Double.MAX_VALUE;
+ for (int i = 0; i < world.length; i += 3) {
+ if (world[i] < minX) minX = world[i];
+ if (world[i] > maxX) maxX = world[i];
+ if (world[i + 1] < minY) minY = world[i + 1];
+ if (world[i + 1] > maxY) maxY = world[i + 1];
+ if (world[i + 2] < minZ) minZ = world[i + 2];
+ if (world[i + 2] > maxZ) maxZ = world[i + 2];
+ }
+ boundingBox = new Box(new Point3D(minX, minY, minZ),
+ new Point3D(maxX, maxY, maxZ));
+ }
+
+ public int triCount() {
+ return triCount;
+ }
+
+ @Override
+ public Box getBoundingBox() {
+ return boundingBox;
+ }
+
+ @Override
+ public int getTransformWeight(final RenderingContext renderingContext) {
+ return Math.max(1, triCount);
+ }
+
+ /**
+ * Transforms every triangle of the block with the composed top
+ * transform of the stack (hoisted out of the loop), culls (near
+ * plane, subpixel with verdict cache, viewport) and queues a thin
+ * handle per surviving triangle. All expressions replicate
+ * {@code TransformStack.transform} /
+ * {@code Vertex.calculateLocationRelativeToViewer} exactly, so output
+ * is bit-identical with the object-backed path.
+ */
+ @Override
+ public void transform(final TransformStack transforms,
+ final RenderAggregator aggregator,
+ final RenderingContext renderingContext) {
+ final int slot = renderingContext.vertexSlot;
+ final double[] px = projX[slot];
+ final double[] py = projY[slot];
+ final double[] cz = camZ[slot];
+ final int[] cref = clipRef[slot];
+ clipUsed[slot] = 0;
+
+ transforms.getTopTransform(top);
+ final double r0 = top[0], r1 = top[1], r2 = top[2];
+ final double r3 = top[3], r4 = top[4], r5 = top[5];
+ final double r6 = top[6], r7 = top[7], r8 = top[8];
+ final double t0 = top[9], t1 = top[10], t2 = top[11];
+
+ final double near = renderingContext.nearPlaneDistance;
+ final double scale = renderingContext.projectionScale;
+ final double centerX = renderingContext.centerCoordinate.x;
+ final double centerY = renderingContext.centerCoordinate.y;
+ final double stereo = renderingContext.stereoViewportOffsetX;
+
+ // Hi-Z whole-block occlusion: test the world AABB against last
+ // frame's depth pyramid before touching a single triangle.
+ // Skipped in stereo (the pyramid is mono-view) and whenever a
+ // corner crosses the near plane (its projection is unreliable).
+ final HiZPyramid hiz = renderingContext.occlusionPyramid;
+ if (hiz != null
+ && renderingContext.stereoEye == StereoEye.NONE) {
+ hiz.blocksTested.incrementAndGet();
+ final Point3D lo = boundingBox.p1, hi = boundingBox.p2;
+ double ax1 = Double.MAX_VALUE, ay1 = Double.MAX_VALUE;
+ double ax2 = -Double.MAX_VALUE, ay2 = -Double.MAX_VALUE;
+ double nearestW = -Double.MAX_VALUE;
+ boolean usable = true;
+ for (int c = 0; c < 8; c++) {
+ final double wx = (c & 1) != 0 ? hi.x : lo.x;
+ final double wy = (c & 2) != 0 ? hi.y : lo.y;
+ final double wz = (c & 4) != 0 ? hi.z : lo.z;
+ final double ccz = r6 * wx + r7 * wy + r8 * wz + t2;
+ if (ccz <= near) {
+ usable = false;
+ break;
+ }
+ final double ccx = r0 * wx + r1 * wy + r2 * wz + t0;
+ final double ccy = r3 * wx + r4 * wy + r5 * wz + t1;
+ final double sx = ((ccx / ccz) * scale) + centerX + stereo;
+ final double sy = ((ccy / ccz) * scale) + centerY;
+ if (sx < ax1) ax1 = sx;
+ if (sx > ax2) ax2 = sx;
+ if (sy < ay1) ay1 = sy;
+ if (sy > ay2) ay2 = sy;
+ final double w = 1d / ccz;
+ if (w > nearestW) nearestW = w;
+ }
+ if (usable && ax1 <= ax2 && ay1 <= ay2
+ && hiz.occluded(ax1, ay1, ax2, ay2, nearestW)) {
+ hiz.blocksCulled.incrementAndGet();
+ return;
+ }
+ }
+ final double cullThreshold = renderingContext.subpixelCullingThreshold;
+ final int epoch = renderingContext.subpixelCullingEpoch;
+ final double rMinX = renderingContext.renderMinX;
+ final double rMaxX = renderingContext.renderMaxX;
+ final double rMinY = renderingContext.renderMinY;
+ final double rMaxY = renderingContext.renderMaxY;
+
+ for (int t = 0; t < triCount; t++) {
+ if (cullThreshold > 0 && cullEpoch[t] == epoch)
+ continue;
+
+ final int w = t * 9;
+ // Same expression order as TransformStack.transform.
+ final double x0 = world[w], y0 = world[w + 1], z0 = world[w + 2];
+ final double cx0 = r0 * x0 + r1 * y0 + r2 * z0 + t0;
+ final double cy0 = r3 * x0 + r4 * y0 + r5 * z0 + t1;
+ final double cz0 = r6 * x0 + r7 * y0 + r8 * z0 + t2;
+ final double x1 = world[w + 3], y1 = world[w + 4], z1 = world[w + 5];
+ final double cx1 = r0 * x1 + r1 * y1 + r2 * z1 + t0;
+ final double cy1 = r3 * x1 + r4 * y1 + r5 * z1 + t1;
+ final double cz1 = r6 * x1 + r7 * y1 + r8 * z1 + t2;
+ final double x2 = world[w + 6], y2 = world[w + 7], z2 = world[w + 8];
+ final double cx2 = r0 * x2 + r1 * y2 + r2 * z2 + t0;
+ final double cy2 = r3 * x2 + r4 * y2 + r5 * z2 + t1;
+ final double cz2 = r6 * x2 + r7 * y2 + r8 * z2 + t2;
+
+ final boolean in0 = cz0 > near;
+ final boolean in1 = cz1 > near;
+ final boolean in2 = cz2 > near;
+
+ if (!in0 && !in1 && !in2) {
+ cref[t] = -1;
+ continue;
+ }
+
+ final int v = t * 3;
+ if (!(in0 && in1 && in2)) {
+ clipAndQueue(t, v, slot, cx0, cy0, cz0, cx1, cy1, cz1,
+ cx2, cy2, cz2, in0, in1, in2, near, cref,
+ aggregator, renderingContext);
+ continue;
+ }
+
+ cref[t] = -1;
+ cz[v] = cz0;
+ cz[v + 1] = cz1;
+ cz[v + 2] = cz2;
+ // Same expression order as
+ // Vertex.calculateLocationRelativeToViewer (divide, scale,
+ // add center, add stereo offset).
+ final double sx0 = ((cx0 / cz0) * scale) + centerX + stereo;
+ final double sy0 = ((cy0 / cz0) * scale) + centerY;
+ final double sx1 = ((cx1 / cz1) * scale) + centerX + stereo;
+ final double sy1 = ((cy1 / cz1) * scale) + centerY;
+ final double sx2 = ((cx2 / cz2) * scale) + centerX + stereo;
+ final double sy2 = ((cy2 / cz2) * scale) + centerY;
+ px[v] = sx0;
+ py[v] = sy0;
+ px[v + 1] = sx1;
+ py[v + 1] = sy1;
+ px[v + 2] = sx2;
+ py[v + 2] = sy2;
+ final double triZ = (cz0 + cz1 + cz2) / 3;
+
+ final double minX = Math.min(sx0, Math.min(sx1, sx2));
+ final double maxX = Math.max(sx0, Math.max(sx1, sx2));
+ final double minY = Math.min(sy0, Math.min(sy1, sy2));
+ final double maxY = Math.max(sy0, Math.max(sy1, sy2));
+
+ // Publish the same per-slot state an object-backed triangle
+ // would have written (paint margins are 0 for mesh tris):
+ // comparator and tile binning then read plain fields.
+ handles[t].publishSlotState(slot, triZ, minY, maxY, minX, maxX);
+
+ // Subpixel verdict with per-triangle cache (same raw-span
+ // semantics as AbstractCoordinateShape).
+ if (cullThreshold > 0
+ && maxX - minX < cullThreshold
+ && maxY - minY < cullThreshold) {
+ cullEpoch[t] = epoch;
+ continue;
+ }
+
+ // Viewport cull (paint margins are 0 for mesh triangles).
+ if (maxX < rMinX || minX >= rMaxX || maxY < rMinY || minY >= rMaxY)
+ continue;
+
+ // Mipmap metric's visible side, once per slot instead of per
+ // tile: edge12 + edge13 + edge23, the same expression the
+ // paint core ran per tile (getDistanceTo sequence).
+ final double dx01 = sx0 - sx1, dy01 = sy0 - sy1;
+ final double dx02 = sx0 - sx2, dy02 = sy0 - sy2;
+ final double dx12 = sx1 - sx2, dy12 = sy1 - sy2;
+ screenPerim[slot][t] = Math.sqrt(dx01 * dx01 + dy01 * dy01)
+ + Math.sqrt(dx02 * dx02 + dy02 * dy02)
+ + Math.sqrt(dx12 * dx12 + dy12 * dy12);
+
+ aggregator.queueShapeForRendering(handles[t]);
+ }
+ }
+
+ /**
+ * Near-plane clip for one straddling triangle, Sutherland-Hodgman
+ * over the three edges with the exact interpolation expressions of
+ * {@code AbstractCoordinateShape.interpolateAtPlane}. Output goes to
+ * the slot's grow-only clip store; the handle is queued with a packed
+ * reference.
+ */
+ private void clipAndQueue(final int t, final int v, final int slot,
+ final double cx0, final double cy0, final double cz0,
+ final double cx1, final double cy1, final double cz1,
+ final double cx2, final double cy2, final double cz2,
+ final boolean in0, final boolean in1, final boolean in2,
+ final double near, final int[] cref,
+ final RenderAggregator aggregator,
+ final RenderingContext renderingContext) {
+ double[] store = clipStore[slot];
+ int used = clipUsed[slot];
+ if (used + CLIP_ENTRY > store.length) {
+ final double[] grown = new double[store.length * 2];
+ System.arraycopy(store, 0, grown, 0, used);
+ store = grown;
+ clipStore[slot] = grown;
+ final double[] grownTtd = new double[grown.length / CLIP_ENTRY];
+ System.arraycopy(clipTtd[slot], 0, grownTtd, 0, clipTtd[slot].length);
+ clipTtd[slot] = grownTtd;
+ }
+ final int base = used;
+ clipTtd[slot][base / CLIP_ENTRY] = uvPerimeter[t];
+
+ final double scale = renderingContext.projectionScale;
+ final double centerX = renderingContext.centerCoordinate.x;
+ final double centerY = renderingContext.centerCoordinate.y;
+ final double stereo = renderingContext.stereoViewportOffsetX;
+
+ final double[] cx = {cx0, cx1, cx2};
+ final double[] cy = {cy0, cy1, cy2};
+ final double[] czz = {cz0, cz1, cz2};
+ final boolean[] in = {in0, in1, in2};
+ final int uvi = t * 6;
+
+ int n = 0;
+ double sumZ = 0;
+ for (int i = 0; i < 3; i++) {
+ final int j = (i + 1) % 3;
+ final boolean currentIn = in[i];
+ final boolean nextIn = in[j];
+ if (currentIn) {
+ store[used++] = cx[i];
+ store[used++] = cy[i];
+ store[used++] = czz[i];
+ store[used++] = uv[uvi + i * 2];
+ store[used++] = uv[uvi + i * 2 + 1];
+ // setCameraSpaceCoordinate expression, same order
+ store[used++] = ((cx[i] / czz[i]) * scale) + centerX + stereo;
+ store[used++] = ((cy[i] / czz[i]) * scale) + centerY;
+ n++;
+ sumZ += czz[i];
+ }
+ if (currentIn != nextIn) {
+ final double tt = (near - czz[i]) / (czz[j] - czz[i]);
+ final double ix = cx[i] + (cx[j] - cx[i]) * tt;
+ final double iy = cy[i] + (cy[j] - cy[i]) * tt;
+ final double iz = czz[i] + (czz[j] - czz[i]) * tt;
+ store[used++] = ix;
+ store[used++] = iy;
+ store[used++] = iz;
+ store[used++] = uv[uvi + i * 2]
+ + (uv[uvi + j * 2] - uv[uvi + i * 2]) * tt;
+ store[used++] = uv[uvi + i * 2 + 1]
+ + (uv[uvi + j * 2 + 1] - uv[uvi + i * 2 + 1]) * tt;
+ store[used++] = ((ix / iz) * scale) + centerX + stereo;
+ store[used++] = ((iy / iz) * scale) + centerY;
+ n++;
+ sumZ += iz;
+ }
+ }
+
+ // Degenerate sliver: fewer loop points than a renderable triangle.
+ if (n < 3) {
+ cref[t] = -1;
+ return;
+ }
+ clipUsed[slot] = used;
+ cref[t] = (base << 3) | n;
+ // Object path averages Z and derives bounds over the clipped loop
+ double cMinX = Double.MAX_VALUE, cMaxX = -Double.MAX_VALUE;
+ double cMinY = Double.MAX_VALUE, cMaxY = -Double.MAX_VALUE;
+ for (int i = 0; i < n; i++) {
+ final double sx = store[base + i * CLIP_STRIDE + 5];
+ final double sy = store[base + i * CLIP_STRIDE + 6];
+ if (sx < cMinX) cMinX = sx;
+ if (sx > cMaxX) cMaxX = sx;
+ if (sy < cMinY) cMinY = sy;
+ if (sy > cMaxY) cMaxY = sy;
+ }
+ handles[t].publishSlotState(slot, sumZ / n, cMinY, cMaxY, cMinX, cMaxX);
+ aggregator.queueShapeForRendering(handles[t]);
+ }
+
+ // ---- handle-facing accessors (package-private) ----
+
+ double camZ(final int slot, final int tri, final int vertex) {
+ return camZ[slot][tri * 3 + vertex];
+ }
+
+ Texture texture(final int tri) {
+ return textures[tri];
+ }
+
+ boolean backfaceCull() {
+ return backfaceCull;
+ }
+
+ int clipOffset(final int slot, final int tri) {
+ final int ref = clipRef[slot][tri];
+ return ref < 0 ? -1 : ref >> 3;
+ }
+
+ int clipCount(final int slot, final int tri) {
+ return clipRef[slot][tri] & 7;
+ }
+
+ double[] clipStore(final int slot) {
+ return clipStore[slot];
+ }
+
+ double clipTtd(final int slot, final int clipOffset) {
+ return clipTtd[slot][clipOffset / CLIP_ENTRY];
+ }
+
+ /** The triangle's UV perimeter, precomputed at build (see field). */
+ double uvPerimeter(final int tri) {
+ return uvPerimeter[tri];
+ }
+
+ /**
+ * The triangle's screen-edge perimeter for this slot, precomputed in
+ * the transform loop (only valid for triangles queued unclipped).
+ */
+ double screenPerim(final int slot, final int tri) {
+ return screenPerim[slot][tri];
+ }
+
+ /**
+ * Loads one unclipped triangle vertex (screen + UV) into the scratch
+ * carriers, values exactly as computed at transform time.
+ */
+ void loadScreenVertex(final Point2D screen, final Point2D uvOut,
+ final int slot, final int tri, final int vertex,
+ final RenderingContext ctx) {
+ final int v = tri * 3 + vertex;
+ screen.x = projX[slot][v];
+ screen.y = projY[slot][v];
+ uvOut.x = uv[tri * 6 + vertex * 2];
+ uvOut.y = uv[tri * 6 + vertex * 2 + 1];
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+
+/**
+ * Textured triangle rendering with perspective-correct UV mapping.
+ *
+ * <p>Textured triangles apply 2D textures to 3D triangles using UV coordinates.
+ * Quake-style subdivided perspective correction (per-scanline recovery of exact
+ * u/v from linearly interpolated u/z, v/z, 1/z) keeps textures correct at any
+ * triangle size, so no tessellation is needed.</p>
+ *
+ * <p>Key classes:</p>
+ * <ul>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.texturedpolygon.TexturedTriangle} -
+ * The base textured triangle with perspective-correct scanline rendering</li>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.texturedpolygon.PerspectiveBorderInterpolator} -
+ * Edge interpolation of u/z, v/z, 1/z gradients</li>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.texturedpolygon.PolygonBorderInterpolator} -
+ * Affine edge interpolation (fallback path)</li>
+ * </ul>
+ *
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.texturedpolygon.TexturedTriangle
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.texture.Texture
+ */
+
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.texturedpolygon;
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.Billboard;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.textcanvas.TextCanvas;
+import eu.svjatoslav.aukio.e3d.renderer.raster.texture.Texture;
+
+import java.awt.Font;
+
+/**
+ * A text label rendered as a billboard texture that always faces the camera.
+ *
+ * <p>This shape renders a single line of text onto a {@link Texture} using the cell metrics
+ * defined in {@link TextCanvas} ({@link TextCanvas#FONT_CHAR_WIDTH_TEXTURE_PIXELS},
+ * {@link TextCanvas#FONT_CHAR_HEIGHT_TEXTURE_PIXELS}), then displays the texture as a
+ * forward-oriented billboard via its {@link Billboard} superclass. The result
+ * is a text label that remains readable from any viewing angle.</p>
+ *
+ * <p><b>Usage example:</b></p>
+ * <pre>{@code
+ * // Create a red text label at position (0, -50, 300)
+ * ForwardOrientedTextBlock label = new ForwardOrientedTextBlock(
+ * new Point3D(0, -50, 300),
+ * 1.0,
+ * 2,
+ * "Hello, World!",
+ * Color.RED
+ * );
+ * shapeCollection.addShape(label);
+ * }</pre>
+ *
+ * @see Billboard
+ * @see TextCanvas
+ * @see Texture
+ */
+public class ForwardOrientedTextBlock extends Billboard {
+
+ /**
+ * The font used to render the label text. Matches the SDF text
+ * pipeline's family (Liberation Mono Bold, Courier-metric-compatible)
+ * at the cell size used by {@link TextCanvas}.
+ */
+ private static final Font FONT = createFont();
+
+ private static Font createFont() {
+ final Font font = new Font("Liberation Mono", Font.BOLD, 30);
+ if (!font.getFamily().toLowerCase().contains("liberation")) {
+ return new Font("Monospaced", Font.BOLD, 30);
+ }
+ return font;
+ }
+
+ /**
+ * Creates a new forward-oriented text block at the given 3D position.
+ *
+ * @param point the 3D position where the text label is placed
+ * @param scale the scale factor controlling the rendered size of the text
+ * @param maxUpscaleFactor the maximum mipmap upscale factor for the backing texture
+ * @param text the text string to render
+ * @param textColor the color of the rendered text
+ */
+ public ForwardOrientedTextBlock(final Point3D point, final double scale,
+ final int maxUpscaleFactor, final String text,
+ final eu.svjatoslav.aukio.e3d.renderer.raster.Color textColor) {
+ super(point, scale, getTexture(text, maxUpscaleFactor, textColor));
+
+ }
+
+ /**
+ * Creates a {@link Texture} containing the rendered text string.
+ *
+ * <p>The texture dimensions are calculated from the text length and the cell metrics
+ * defined in {@link TextCanvas}. Each character is drawn individually at the appropriate
+ * horizontal offset.</p>
+ *
+ * @param text the text string to render into the texture
+ * @param maxUpscaleFactor the maximum mipmap upscale factor for the texture
+ * @param textColor the color of the rendered text
+ * @return a new {@link Texture} containing the rendered text
+ */
+ public static Texture getTexture(final String text,
+ final int maxUpscaleFactor,
+ final eu.svjatoslav.aukio.e3d.renderer.raster.Color textColor) {
+
+ final Texture texture = new Texture(text.length()
+ * TextCanvas.FONT_CHAR_WIDTH_TEXTURE_PIXELS, TextCanvas.FONT_CHAR_HEIGHT_TEXTURE_PIXELS,
+ maxUpscaleFactor);
+
+ // Put blue background to test if texture has correct size
+ // texture.graphics.setColor(Color.BLUE);
+ // texture.graphics.fillRect(0, 0, texture.primaryBitmap.width,
+ // texture.primaryBitmap.width);
+
+ texture.graphics.setFont(FONT);
+ texture.graphics.setColor(textColor.toAwtColor());
+
+ for (int c = 0; c < text.length(); c++)
+ texture.graphics.drawChars(new char[]{text.charAt(c),}, 0, 1,
+ (c * TextCanvas.FONT_CHAR_WIDTH_TEXTURE_PIXELS),
+ (int) (TextCanvas.FONT_CHAR_HEIGHT_TEXTURE_PIXELS / 1.45));
+
+ return texture;
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point2D;
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.math.Transform;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.line.Line;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.textcanvas.TextCanvas;
+
+import java.util.List;
+
+/**
+ * A 2D graph visualization rendered in 3D space.
+ *
+ * <p>Plots a series of {@link Point2D} data points as a connected line graph, overlaid on a
+ * grid with horizontal and vertical grid lines, axis labels, and a title. The graph is
+ * rendered in the XY plane at the specified 3D location, with all dimensions scaled by
+ * a configurable scale factor.</p>
+ *
+ * <p>The graph uses the following default configuration:</p>
+ * <ul>
+ * <li>X-axis range: {@code 0} to {@code 20} (world units before scaling)</li>
+ * <li>Y-axis range: {@code -2} to {@code 2}</li>
+ * <li>Grid spacing: {@code 0.5} in both horizontal and vertical directions</li>
+ * <li>Grid color: semi-transparent blue ({@code rgba(100, 100, 250, 100)})</li>
+ * <li>Plot color: semi-transparent red ({@code rgba(255, 0, 0, 100)})</li>
+ * </ul>
+ *
+ * <p><b>Usage example:</b></p>
+ * <pre>{@code
+ * // Prepare data points
+ * List<Point2D> data = new ArrayList<>();
+ * for (double x = 0; x <= 20; x += 0.1) {
+ * data.add(new Point2D(x, Math.sin(x)));
+ * }
+ *
+ * // Create a graph at position (0, 0, 500) with scale factor 10
+ * Graph graph = new Graph(10.0, data, "sin(x)", new Point3D(0, 0, 500));
+ *
+ * // Add to the scene
+ * shapeCollection.addShape(graph);
+ * }</pre>
+ *
+ * @see Line
+ * @see TextCanvas
+ * @see AbstractCompositeShape
+ */
+public class Graph extends AbstractCompositeShape {
+
+ /** The width of the graph in unscaled world units. */
+ private final double width;
+ /** The minimum Y-axis value. */
+ private final double yMin;
+ /** The maximum Y-axis value. */
+ private final double yMax;
+ /** The spacing between vertical grid lines along the X-axis. */
+ private final double horizontalStep;
+ /** The spacing between horizontal grid lines along the Y-axis. */
+ private final double verticalStep;
+ /** The color used for grid lines. */
+ private final Color gridColor;
+ /** The width of grid lines in world units (after scaling). */
+ private final double lineWidth;
+ /** The color used for the data plot line. */
+ private final Color plotColor;
+
+ /**
+ * Creates a new graph visualization at the specified 3D location.
+ *
+ * <p>The graph is constructed with grid lines, axis labels, plotted data, and a title
+ * label. All spatial dimensions are multiplied by the given scale factor.</p>
+ *
+ * @param scale the scale factor applied to all spatial dimensions of the graph
+ * @param data the list of 2D data points to plot; consecutive points are connected by lines
+ * @param label the title text displayed above the graph
+ * @param location the 3D position of the graph's origin in the scene
+ */
+ public Graph(final double scale, final List<Point2D> data,
+ final String label, final Point3D location) {
+ super(location);
+
+ width = 20;
+
+ yMin = -2;
+ yMax = 2;
+
+ horizontalStep = 0.5;
+ verticalStep = 0.5;
+
+ gridColor = new Color(100, 100, 250, 100);
+
+ lineWidth = 0.1 * scale;
+ plotColor = new Color(255, 0, 0, 100);
+
+ addVerticalLines(scale);
+ addXLabels(scale);
+ addHorizontalLinesAndLabels(scale);
+ plotData(scale, data);
+
+ final Point3D labelLocation = new Point3D(width / 2, yMax + 0.5, 0)
+ .multiply(scale);
+
+ final TextCanvas labelCanvas = new TextCanvas(new Transform(
+ labelLocation), label, Color.WHITE, Color.TRANSPARENT);
+
+ addShape(labelCanvas);
+ }
+
+ private void addHorizontalLinesAndLabels(final double scale) {
+ for (double y = yMin; y <= yMax; y += verticalStep) {
+
+ final Point3D p1 = new Point3D(0, y, 0).multiply(scale);
+
+ final Point3D p2 = new Point3D(width, y, 0).multiply(scale);
+
+ final Line line = new Line(p1, p2, gridColor, lineWidth);
+
+ addShape(line);
+
+ final Point3D labelLocation = new Point3D(-0.5, y, 0)
+ .multiply(scale);
+
+ final TextCanvas label = new TextCanvas(
+ new Transform(labelLocation), String.valueOf(y),
+ Color.WHITE, Color.TRANSPARENT);
+
+ addShape(label);
+
+ }
+ }
+
+ private void addVerticalLines(final double scale) {
+ for (double x = 0; x <= width; x += horizontalStep) {
+
+ final Point3D p1 = new Point3D(x, yMin, 0).multiply(scale);
+ final Point3D p2 = new Point3D(x, yMax, 0).multiply(scale);
+
+ final Line line = new Line(p1, p2, gridColor, lineWidth);
+
+ addShape(line);
+
+ }
+ }
+
+ private void addXLabels(final double scale) {
+ for (double x = 0; x <= width; x += horizontalStep * 2) {
+ final Point3D labelLocation = new Point3D(x, yMin - 0.4, 0)
+ .multiply(scale);
+
+ final TextCanvas label = new TextCanvas(
+ new Transform(labelLocation), String.valueOf(x),
+ Color.WHITE, Color.TRANSPARENT);
+
+ addShape(label);
+ }
+ }
+
+ private void plotData(final double scale, final List<Point2D> data) {
+ Point3D previousPoint = null;
+ for (final Point2D point : data) {
+
+ final Point3D p3d = new Point3D(point.x, point.y, 0).multiply(scale);
+
+ if (previousPoint != null) {
+
+ final Line line = new Line(previousPoint, p3d, plotColor,
+ 0.4 * scale);
+
+ addShape(line);
+ }
+
+ previousPoint = p3d;
+ }
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.GlowingPoint;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape;
+
+/**
+ * A visual marker that indicates a light source position in the 3D scene.
+ *
+ * <p>Rendered as a glowing point that provides a clear, lightweight visual
+ * indicator useful for debugging light placement in the scene.</p>
+ *
+ * <p><b>Usage example:</b></p>
+ * <pre>{@code
+ * // Place a yellow light source marker at position (100, -50, 200)
+ * LightSourceMarker marker = new LightSourceMarker(
+ * new Point3D(100, -50, 200),
+ * Color.YELLOW
+ * );
+ * shapeCollection.addShape(marker);
+ * }</pre>
+ *
+ * @see GlowingPoint
+ * @see AbstractCompositeShape
+ */
+public class LightSourceMarker extends AbstractCompositeShape {
+
+ /**
+ * Creates a new light source marker at the specified location.
+ *
+ * @param location the 3D position of the marker in the scene
+ * @param color the color of the glowing point
+ */
+ public LightSourceMarker(final Point3D location, final Color color) {
+ super(location);
+ addShape(new GlowingPoint(new Point3D(0, 0, 0), 15, color));
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.gi.LightmappedTriangle;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.AbstractCoordinateShape;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.AbstractShape;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon.SolidPolygon;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Composite shape whose solid polygons can render as lightmapped
+ * triangles for the global illumination system.
+ *
+ * <p><b>Lightmapping:</b> when enabled, every {@link SolidPolygon}
+ * (including those inside nested composites, which are flattened) is
+ * wrapped as a {@link LightmappedTriangle} with its own lightmap texture,
+ * and the GI system paints light across its surface instead of leaving
+ * it a single flat color. Rebuild is automatic via the normal
+ * cache-invalidation path.</p>
+ *
+ * <p><b>Ordering:</b> none required — the engine's z-buffer resolves
+ * visibility per pixel, so this class needs no spatial ordering
+ * structure of its own. Nested composites are flattened assuming
+ * identity transforms (vertices are used in the composite's local
+ * space); animate transforms above this composite, not inside it.</p>
+ *
+ * @see LightmappedTriangle the per-fragment lightmap carrier
+ * @see AbstractCompositeShape the base composite (fan-triangulates
+ * N-vertex polygons when building the render list)
+ */
+public class LightmappedCompositeShape extends AbstractCompositeShape {
+
+ /**
+ * When true, the composite's polygons render as
+ * {@link LightmappedTriangle}s: each polygon gets its own lightmap
+ * texture and the GI system paints light across its surface.
+ */
+ private boolean lightmappingEnabled;
+
+ /** World units per lightmap texel (smaller = finer GI detail). */
+ private double lightmapUnitsPerTexel = 12.0;
+
+ /**
+ * Replaces solid polygons with lightmapped wrappers when lightmapping
+ * is enabled; otherwise returns the list unchanged.
+ *
+ * @param renderList the render list built from the shape registry
+ * @return lightmapped wrappers + non-polygon passthrough shapes
+ */
+ @Override
+ protected List<AbstractShape> postprocessRenderList(final List<AbstractShape> renderList) {
+ if (!lightmappingEnabled)
+ return renderList;
+
+ final List<AbstractShape> result = new ArrayList<>(renderList.size());
+ for (final AbstractShape shape : renderList) {
+ if (shape instanceof SolidPolygon) {
+ wrapLightmapped((SolidPolygon) shape, result);
+ } else if (shape instanceof AbstractCompositeShape) {
+ // Flatten nested composites. Assumes identity transforms
+ // on the nested composite chain.
+ for (final SolidPolygon polygon
+ : ((AbstractCompositeShape) shape).extractSolidPolygons())
+ wrapLightmapped(polygon, result);
+ } else {
+ result.add(shape);
+ }
+ }
+ return result;
+ }
+
+ /**
+ * Enables or disables lightmapping. When enabled, the composite's
+ * polygons render as {@link LightmappedTriangle}s with per-polygon
+ * lightmap textures filled by the global illumination system.
+ * Rebuilds the render list on the next frame.
+ *
+ * @param enabled true to render polygons lightmapped
+ */
+ public void setLightmappingEnabled(final boolean enabled) {
+ if (lightmappingEnabled != enabled) {
+ lightmappingEnabled = enabled;
+ setCacheNeedsRebuild(true);
+ }
+ }
+
+ /**
+ * Returns whether lightmapping is enabled.
+ *
+ * @return true when polygons render as lightmapped triangles
+ */
+ public boolean isLightmappingEnabled() {
+ return lightmappingEnabled;
+ }
+
+ /**
+ * Sets the lightmap resolution. Default 12 world units per texel:
+ * a 100-unit wall cell gets an 8x8 lightmap. Halving the units
+ * quadruples the GI tracing work; finer texels are the ONLY way to
+ * smoother shadow edges (there is no upsampling). Takes effect on the
+ * next render list rebuild.
+ *
+ * @param unitsPerTexel world units per texel
+ */
+ public void setLightmapUnitsPerTexel(final double unitsPerTexel) {
+ lightmapUnitsPerTexel = unitsPerTexel;
+ setCacheNeedsRebuild(true);
+ }
+
+ /**
+ * Fan-triangulates a polygon (triangles pass through as-is) and wraps
+ * each triangle into a lightmapped textured triangle with the same
+ * geometry, color and culling. The initial texture is dim; the GI
+ * system converges it to full lighting within seconds.
+ *
+ * @param polygon the polygon to wrap (any vertex count >= 3)
+ * @param out the list receiving the lightmapped triangles
+ */
+ private void wrapLightmapped(final SolidPolygon polygon, final List<AbstractShape> out) {
+ final int vertexCount = polygon.getVertexCount();
+ if (vertexCount == 3) {
+ out.add(wrapTriangle(polygon));
+ return;
+ }
+ // Fan: anchor vertex 0, then consecutive pairs
+ final Point3D anchor = polygon.vertices.get(0).coordinate;
+ for (int i = 1; i + 1 < vertexCount; i++) {
+ final SolidPolygon triangle = new SolidPolygon(
+ anchor,
+ polygon.vertices.get(i).coordinate,
+ polygon.vertices.get(i + 1).coordinate,
+ polygon.getColor());
+ triangle.setShadingEnabled(polygon.isShadingEnabled());
+ triangle.setBackfaceCulling(polygon.isBackfaceCullingEnabled());
+ triangle.setMouseInteractionController(polygon.mouseInteractionController);
+ out.add(wrapTriangle(triangle));
+ }
+ }
+
+ /**
+ * Wraps one triangle into a lightmapped textured triangle with the
+ * same geometry, color and culling.
+ */
+ private AbstractCoordinateShape wrapTriangle(final SolidPolygon polygon) {
+ final Point3D a = polygon.vertices.get(0).coordinate;
+ final Point3D b = polygon.vertices.get(1).coordinate;
+ final Point3D c = polygon.vertices.get(2).coordinate;
+
+ // Normal: right-handed cross(b-a, c-a).
+ final double e1x = b.x - a.x, e1y = b.y - a.y, e1z = b.z - a.z;
+ final double e2x = c.x - a.x, e2y = c.y - a.y, e2z = c.z - a.z;
+ double nx = e1y * e2z - e1z * e2y;
+ double ny = e1z * e2x - e1x * e2z;
+ double nz = e1x * e2y - e1y * e2x;
+ final double len = Math.sqrt(nx * nx + ny * ny + nz * nz);
+ if (len > 0) {
+ nx /= len;
+ ny /= len;
+ nz /= len;
+ }
+
+ final LightmappedTriangle triangle = new LightmappedTriangle(
+ a, b, c, polygon.getColor(), lightmapUnitsPerTexel,
+ nx, ny, nz);
+ triangle.setBackfaceCulling(polygon.isBackfaceCullingEnabled());
+ triangle.setMouseInteractionController(polygon.mouseInteractionController);
+ return triangle;
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point2D;
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.math.Transform;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Vertex;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.texturedpolygon.TexturedTriangle;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape;
+import eu.svjatoslav.aukio.e3d.renderer.raster.texture.Texture;
+
+/**
+ * A rectangular shape with texture mapping, composed of two textured triangles.
+ *
+ * <p>This composite shape creates a textured rectangle in 3D space by splitting it into
+ * two {@link TexturedTriangle} triangles that share a common {@link Texture}. The rectangle
+ * is centered at the origin of its local coordinate system, with configurable world-space
+ * dimensions and independent texture resolution.</p>
+ *
+ * <p>The contained {@link Texture} object is accessible via {@link #getTexture()}, allowing
+ * dynamic rendering to the texture surface (e.g., drawing text, images, or procedural content)
+ * after construction.</p>
+ *
+ * <p><b>Usage example:</b></p>
+ * <pre>{@code
+ * // Create a 200x100 textured rectangle at position (0, 0, 300)
+ * Transform transform = new Transform(new Point3D(0, 0, 300));
+ * TexturedRectangle rect = new TexturedRectangle(transform, 200, 100, 2);
+ *
+ * // Draw onto the texture dynamically
+ * Texture tex = rect.getTexture();
+ * tex.graphics.setColor(java.awt.Color.RED);
+ * tex.graphics.fillRect(0, 0, 50, 50);
+ *
+ * // Add to the scene
+ * shapeCollection.addShape(rect);
+ * }</pre>
+ *
+ * @see TexturedTriangle
+ * @see Texture
+ * @see AbstractCompositeShape
+ */
+public class TexturedRectangle extends AbstractCompositeShape {
+
+ /** Top-left corner position in local 3D coordinates. */
+ public Point3D topLeft;
+ /** Top-right corner position in local 3D coordinates. */
+ public Point3D topRight;
+ /** Bottom-right corner position in local 3D coordinates. */
+ public Point3D bottomRight;
+ /** Bottom-left corner position in local 3D coordinates. */
+ public Point3D bottomLeft;
+ /** Top-left corner mapping in texture coordinates (pixels). */
+ public Point2D textureTopLeft;
+ /** Top-right corner mapping in texture coordinates (pixels). */
+ public Point2D textureTopRight;
+ /** Bottom-right corner mapping in texture coordinates (pixels). */
+ public Point2D textureBottomRight;
+ /** Bottom-left corner mapping in texture coordinates (pixels). */
+ public Point2D textureBottomLeft;
+ private Texture texture;
+
+ /**
+ * Creates a textured rectangle with only a transform, without initializing geometry.
+ *
+ * <p>After construction, call {@link #initialize(double, double, int, int, int)} to
+ * set up the rectangle's dimensions, texture, and triangle geometry.</p>
+ *
+ * @param transform the position and orientation of this rectangle in the scene
+ */
+ public TexturedRectangle(final Transform transform) {
+ super(transform);
+ }
+
+ /**
+ * Creates a textured rectangle where the texture resolution matches the world-space size.
+ *
+ * <p>This is a convenience constructor equivalent to calling
+ * {@link #TexturedRectangle(Transform, int, int, int, int, int)} with
+ * {@code textureWidth = width} and {@code textureHeight = height}.</p>
+ *
+ * @param transform the position and orientation of this rectangle in the scene
+ * @param width the width of the rectangle in world units (also used as texture width in pixels)
+ * @param height the height of the rectangle in world units (also used as texture height in pixels)
+ * @param maxTextureUpscale the maximum mipmap upscale factor for the texture
+ */
+ public TexturedRectangle(final Transform transform, final int width,
+ final int height, final int maxTextureUpscale) {
+ this(transform, width, height, width, height, maxTextureUpscale);
+ }
+
+ /**
+ * Creates a fully initialized textured rectangle with independent world-space size and texture resolution.
+ *
+ * @param transform the position and orientation of this rectangle in the scene
+ * @param width the width of the rectangle in world units
+ * @param height the height of the rectangle in world units
+ * @param textureWidth the width of the backing texture in pixels
+ * @param textureHeight the height of the backing texture in pixels
+ * @param maxTextureUpscale the maximum mipmap upscale factor for the texture
+ */
+ public TexturedRectangle(final Transform transform, final int width,
+ final int height, final int textureWidth, final int textureHeight,
+ final int maxTextureUpscale) {
+
+ super(transform);
+
+ initialize(width, height, textureWidth, textureHeight,
+ maxTextureUpscale);
+ }
+
+ /**
+ * Returns the backing texture for this rectangle.
+ *
+ * <p>The returned {@link Texture} can be used to draw dynamic content onto the
+ * rectangle's surface via its {@code graphics} field (a {@link java.awt.Graphics2D} instance).</p>
+ *
+ * @return the texture mapped onto this rectangle
+ */
+ public Texture getTexture() {
+ return texture;
+ }
+
+ /**
+ * Initializes the rectangle geometry, texture, and the two constituent textured triangles.
+ *
+ * <p>The rectangle is centered at the local origin: corners span from
+ * {@code (-width/2, -height/2, 0)} to {@code (width/2, height/2, 0)}.
+ * Two {@link TexturedTriangle} triangles are created to cover the full rectangle,
+ * sharing a single {@link Texture} instance.</p>
+ *
+ * @param width the width of the rectangle in world units
+ * @param height the height of the rectangle in world units
+ * @param textureWidth the width of the backing texture in pixels
+ * @param textureHeight the height of the backing texture in pixels
+ * @param maxTextureUpscale the maximum mipmap upscale factor for the texture
+ */
+ public void initialize(final double width, final double height,
+ final int textureWidth, final int textureHeight,
+ final int maxTextureUpscale) {
+
+ topLeft = new Point3D(-width / 2, -height / 2, 0);
+ topRight = new Point3D(width / 2, -height / 2, 0);
+ bottomRight = new Point3D(width / 2, height / 2, 0);
+ bottomLeft = new Point3D(-width / 2, height / 2, 0);
+
+ texture = new Texture(textureWidth, textureHeight, maxTextureUpscale);
+
+ textureTopRight = new Point2D(textureWidth, 0);
+ textureTopLeft = new Point2D(0, 0);
+ textureBottomRight = new Point2D(textureWidth, textureHeight);
+ textureBottomLeft = new Point2D(0, textureHeight);
+
+
+
+
+ final TexturedTriangle texturedPolygon1 = new TexturedTriangle(
+ new Vertex(topLeft, textureTopLeft),
+ new Vertex(topRight, textureTopRight),
+ new Vertex(bottomRight, textureBottomRight), texture);
+
+ texturedPolygon1
+ .setMouseInteractionController(mouseInteractionController);
+
+ final TexturedTriangle texturedPolygon2 = new TexturedTriangle(
+ new Vertex(topLeft, textureTopLeft),
+ new Vertex(bottomLeft, textureBottomLeft),
+ new Vertex(bottomRight, textureBottomRight), texture);
+
+ texturedPolygon2
+ .setMouseInteractionController(mouseInteractionController);
+
+ addShape(texturedPolygon1);
+ addShape(texturedPolygon2);
+ }
+
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base;
+
+import eu.svjatoslav.aukio.e3d.geometry.Box;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Frustum;
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.RenderingContext;
+import eu.svjatoslav.aukio.e3d.gui.ViewSpaceTracker;
+import eu.svjatoslav.aukio.e3d.gui.humaninput.MouseInteractionController;
+import eu.svjatoslav.aukio.e3d.math.Transform;
+import eu.svjatoslav.aukio.e3d.math.TransformStack;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Vertex;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+import eu.svjatoslav.aukio.e3d.renderer.raster.ParallelTransformCoordinator;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.AbstractCoordinateShape;
+import eu.svjatoslav.aukio.e3d.renderer.raster.RenderAggregator;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.AbstractShape;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.line.Line;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon.SolidPolygon;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.texturedpolygon.TexturedTriangle;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+import java.util.concurrent.atomic.AtomicInteger;
+
+/**
+ * A composite shape that groups multiple sub-shapes into a single logical unit.
+ *
+ * <p>Use {@code AbstractCompositeShape} to build complex 3D objects by combining
+ * primitive shapes (lines, polygons, textured polygons) into a group that can be
+ * positioned, rotated, and manipulated as one entity. Sub-shapes can be organized
+ * into named groups for selective visibility toggling.</p>
+ *
+ * <p><b>Usage example - creating a custom composite shape:</b></p>
+ * <pre>{@code
+ * // Create a composite shape at position (0, 0, 200)
+ * AbstractCompositeShape myObject = new AbstractCompositeShape(
+ * new Point3D(0, 0, 200)
+ * );
+ *
+ * // Add sub-shapes
+ * myObject.addShape(new Line(
+ * new Point3D(-50, 0, 0), new Point3D(50, 0, 0),
+ * Color.RED, 2.0
+ * ));
+ *
+ * // Add shapes to a named group for toggling visibility
+ * myObject.addShape(labelShape, "labels");
+ * myObject.hideGroup("labels"); // hide all shapes in "labels" group
+ * myObject.showGroup("labels"); // show them again
+ *
+ * // Add to scene
+ * viewPanel.getRootShapeCollection().addShape(myObject);
+ * }</pre>
+ *
+ * <p><b>Perspective-correct texturing:</b></p>
+ * <p>Textured polygons are rendered with Quake-style perspective-correct scanline
+ * mapping ({@code TexturedTriangle}), so no screen-size tessellation is needed.</p>
+ *
+ * <p><b>Extending this class:</b></p>
+ * <p>Override {@link #beforeTransformHook} to customize shape appearance or behavior
+ * on each frame (e.g., animations, dynamic geometry updates).</p>
+ *
+ * @see SubShape wrapper for individual sub-shapes with group and visibility support
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.shapes.AbstractShape the base shape class
+ */
+public class AbstractCompositeShape extends AbstractShape {
+ /**
+ * Source-of-truth registry of all sub-shapes added to this composite.
+ *
+ * <p>Each sub-shape is wrapped with its group identifier and visibility state.
+ * Shapes are stored in insertion order and remain in this collection even when
+ * hidden (visibility state toggles instead of removal).</p>
+ *
+ * <p><b>Performance note:</b> This list is NOT processed for every frame.
+ * Instead, it serves as the authoritative source from which {@link #cachedRenderList}
+ * is compiled whenever the cache becomes invalid (see {@link #cacheNeedsRebuild}).
+ * Only modifications to this registry (add/remove/show/hide) trigger cache rebuild.</p>
+ *
+ * @see #cachedRenderList the frame-optimized cache derived from this registry
+ * @see #cacheNeedsRebuild the flag controlling when the cache is rebuilt
+ */
+ private final List<SubShape> subShapesRegistry = new ArrayList<>();
+
+ /**
+ * Tracks the distance and angle between the camera and this shape.
+ * Used e.g. by TextCanvas for distance-based rendering mode selection.
+ */
+ private final ViewSpaceTracker viewSpaceTracker;
+
+ /**
+ * Frame-optimized cache of shapes ready for rendering, derived from {@link #subShapesRegistry}.
+ *
+ * <p>This list is processed during every frame in the {@link #transform} method.
+ * It contains:</p>
+ * <ul>
+ * <li>Shapes passing through directly (Line, TexturedTriangle, ...)</li>
+ * <li>Solid polygons with more than 3 vertices - fan-triangulated</li>
+ * </ul>
+ *
+ * <p><b>Caching strategy:</b> The list is rebuilt only when
+ * {@link #cacheNeedsRebuild} is true, avoiding per-frame reconstruction
+ * overhead.</p>
+ *
+ * @see #subShapesRegistry the source registry this cache is derived from
+ * @see #cacheNeedsRebuild the flag that triggers cache regeneration
+ */
+ private List<AbstractShape> cachedRenderList = new ArrayList<>();
+
+ /**
+ * Flag indicating whether {@link #cachedRenderList} needs to be rebuilt from {@link #subShapesRegistry}.
+ *
+ * <p>Set to {@code true} when:</p>
+ * <ul>
+ * <li>A shape is added via {@link #addShape}</li>
+ * <li>A shape is removed via {@link #removeGroup}</li>
+ * <li>Group visibility changes via {@link #showGroup} or {@link #hideGroup}</li>
+ * </ul>
+ *
+ * <p>Set to {@code false} after {@link #rebuildRenderList} completes the cache rebuild.</p>
+ *
+ * <p>This flag enables the performance optimization of avoiding per-frame list
+ * reconstruction - the registry is only re-processed when something actually changed.</p>
+ *
+ * @see #subShapesRegistry the source data that may need reprocessing
+ * @see #cachedRenderList the cache that gets rebuilt when this flag is true
+ */
+ private boolean cacheNeedsRebuild = true;
+
+ /**
+ * Flag indicating this composite is the root scene container (ShapeCollection's root).
+ *
+ * <p>Set via {@link #setRootComposite(boolean)} by ShapeCollection.</p>
+ */
+ private boolean isRootComposite = false;
+
+ /**
+ * The position and orientation transform for this composite shape.
+ * Applied to all sub-shapes during the rendering transform pass.
+ */
+ private Transform transform;
+
+ /**
+ * Creates a composite shape at the world origin with no rotation.
+ */
+ public AbstractCompositeShape() {
+ this(new Transform());
+ }
+
+ /**
+ * Creates a composite shape at the specified location with no rotation.
+ *
+ * @param location the position in world space
+ */
+ public AbstractCompositeShape(final Point3D location) {
+ this(new Transform(location));
+ }
+
+ /**
+ * Creates a composite shape with the specified transform (position and orientation).
+ *
+ * @param transform the initial transform defining position and rotation
+ */
+ public AbstractCompositeShape(final Transform transform) {
+ this.transform = transform;
+ viewSpaceTracker = new ViewSpaceTracker();
+ }
+
+ /**
+ * Adds a sub-shape to this composite shape without a group identifier.
+ *
+ * @param shape the shape to add
+ */
+ public void addShape(final AbstractShape shape) {
+ addShape(shape, null);
+ }
+
+ /**
+ * Adds a sub-shape to this composite shape with an optional group identifier.
+ *
+ * <p>Grouped shapes can be shown, hidden, or removed together using
+ * {@link #showGroup}, {@link #hideGroup}, and {@link #removeGroup}.</p>
+ *
+ * @param shape the shape to add
+ * @param groupId the group identifier, or {@code null} for ungrouped shapes
+ */
+ public void addShape(final AbstractShape shape, final String groupId) {
+ subShapesRegistry.add(new SubShape(shape, groupId, true));
+ cacheNeedsRebuild = true;
+ }
+
+ /**
+ * This method should be overridden by anyone wanting to customize the shape
+ * before it is rendered.
+ *
+ * @param transformPipe the current transform stack
+ * @param context the rendering context for the current frame
+ */
+ public void beforeTransformHook(final TransformStack transformPipe,
+ final RenderingContext context) {
+ }
+
+ /**
+ * Returns the world-space position of this composite shape.
+ *
+ * @return the translation component of this shape's transform
+ */
+ public Point3D getLocation() {
+ return transform.getTranslation();
+ }
+
+ /**
+ * Returns the axis-aligned bounding box encompassing all sub-shapes.
+ *
+ * <p>The bounding box is computed by aggregating the bounds of all visible
+ * sub-shapes, then transforming the result by this composite's own transform.</p>
+ *
+ * <p><b>Caching:</b> The bounding box is recomputed whenever
+ * {@link #cacheNeedsRebuild} is true (shapes added/removed/visibility changed).
+ * For nested composites, the bounds include their local transform offset.</p>
+ *
+ * @return the axis-aligned bounding box in this composite's local coordinates
+ */
+ @Override
+ public Box getBoundingBox() {
+ if (cachedBoundingBox == null || cacheNeedsRebuild) {
+ if (subShapesRegistry.isEmpty()) {
+ return super.getBoundingBox();
+ }
+
+ double minX = Double.MAX_VALUE;
+ double maxX = -Double.MAX_VALUE;
+ double minY = Double.MAX_VALUE;
+ double maxY = -Double.MAX_VALUE;
+ double minZ = Double.MAX_VALUE;
+ double maxZ = -Double.MAX_VALUE;
+
+ for (final SubShape subShape : subShapesRegistry) {
+ if (!subShape.isVisible()) {
+ continue;
+ }
+
+ final AbstractShape shape = subShape.getShape();
+ final Box shapeBounds = shape.getBoundingBox();
+
+ // Get bounds and apply sub-shape's transform if it's a composite
+ Point3D shapeMin = new Point3D(shapeBounds.getMinX(), shapeBounds.getMinY(), shapeBounds.getMinZ());
+ Point3D shapeMax = new Point3D(shapeBounds.getMaxX(), shapeBounds.getMaxY(), shapeBounds.getMaxZ());
+ if (shape instanceof AbstractCompositeShape) {
+ final Transform subTransform = ((AbstractCompositeShape) shape).getTransform();
+ final Point3D subTranslation = subTransform.getTranslation();
+ shapeMin.add(subTranslation);
+ shapeMax.add(subTranslation);
+ }
+
+ minX = Math.min(minX, shapeMin.x);
+ maxX = Math.max(maxX, shapeMax.x);
+ minY = Math.min(minY, shapeMin.y);
+ maxY = Math.max(maxY, shapeMax.y);
+ minZ = Math.min(minZ, shapeMin.z);
+ maxZ = Math.max(maxZ, shapeMax.z);
+ }
+
+ if (minX == Double.MAX_VALUE) {
+ // No visible shapes
+ return super.getBoundingBox();
+ }
+
+ cachedBoundingBox = new Box(
+ new Point3D(minX, minY, minZ),
+ new Point3D(maxX, maxY, maxZ)
+ );
+ }
+ return cachedBoundingBox;
+ }
+
+ /**
+ * Returns the sub-shapes registry (source of truth for all sub-shapes).
+ *
+ * <p>This is the authoritative list of all sub-shapes including hidden ones.
+ * For per-frame rendering, use {@link #cachedRenderList} instead (accessed internally).</p>
+ *
+ * @return the registry list of all sub-shapes with their group and visibility metadata
+ * @see #cachedRenderList the frame-optimized cache derived from this registry
+ */
+ public List<SubShape> getSubShapesRegistry() {
+ return subShapesRegistry;
+ }
+
+ /**
+ * Extracts all SolidPolygon instances from this composite shape.
+ *
+ * <p>Recursively traverses the shape hierarchy and collects all
+ * SolidPolygon instances. Used for CSG operations where polygons
+ * are needed directly without conversion.</p>
+ *
+ * @return list of SolidPolygon instances from this shape hierarchy
+ */
+ public List<SolidPolygon> extractSolidPolygons() {
+ final List<SolidPolygon> result = new ArrayList<>();
+ for (final SubShape subShape : subShapesRegistry) {
+ final AbstractShape shape = subShape.getShape();
+ if (shape instanceof SolidPolygon) {
+ result.add((SolidPolygon) shape);
+ } else if (shape instanceof AbstractCompositeShape) {
+ result.addAll(((AbstractCompositeShape) shape).extractSolidPolygons());
+ }
+ }
+ return result;
+ }
+
+ /**
+ * Returns the view-space tracker that monitors the distance
+ * and angle between the camera and this shape for level-of-detail adjustments.
+ *
+ * @return the view-space tracker for this shape
+ */
+ public ViewSpaceTracker getViewSpaceTracker() {
+ return viewSpaceTracker;
+ }
+
+ /**
+ * Hides all sub-shapes belonging to the specified group.
+ * Hidden shapes are not rendered but remain in the collection.
+ *
+ * @param groupIdentifier the group to hide
+ * @see #showGroup(String)
+ * @see #removeGroup(String)
+ */
+ public void hideGroup(final String groupIdentifier) {
+ for (final SubShape subShape : subShapesRegistry) {
+ if (subShape.matchesGroup(groupIdentifier)) {
+ subShape.setVisible(false);
+ cacheNeedsRebuild = true;
+ }
+ }
+ }
+
+ /**
+ * Permanently removes all sub-shapes belonging to the specified group.
+ *
+ * @param groupIdentifier the group to remove
+ * @see #hideGroup(String)
+ */
+ public void removeGroup(final String groupIdentifier) {
+ final java.util.Iterator<SubShape> iterator = subShapesRegistry
+ .iterator();
+
+ while (iterator.hasNext()) {
+ final SubShape subShape = iterator.next();
+ if (subShape.matchesGroup(groupIdentifier)) {
+ iterator.remove();
+ cacheNeedsRebuild = true;
+ }
+ }
+ }
+
+ /**
+ * Returns all sub-shapes belonging to the specified group.
+ *
+ * @param groupIdentifier the group identifier to match
+ * @return list of matching sub-shapes
+ */
+ public List<SubShape> getGroup(final String groupIdentifier) {
+ final List<SubShape> result = new ArrayList<>();
+ for (int i = 0; i < subShapesRegistry.size(); i++) {
+ final SubShape subShape = subShapesRegistry.get(i);
+ if (subShape.matchesGroup(groupIdentifier))
+ result.add(subShape);
+ }
+ return result;
+ }
+
+ /**
+ * Rebuilds the cached render list if shapes were added, removed, or
+ * visibility changed since the last rebuild.
+ *
+ * @param context the rendering context for logging
+ */
+ private void rebuildRenderListIfNeeded(final RenderingContext context) {
+ if (cacheNeedsRebuild)
+ rebuildRenderList(context);
+ }
+
+ /**
+ * Paint solid elements of this composite shape into given color.
+ *
+ * <p>Applies recursively to nested {@code AbstractCompositeShape} sub-shapes.</p>
+ *
+ * @param color the color to apply to all solid sub-shapes
+ */
+ public void setColor(final Color color) {
+ for (final SubShape subShape : getSubShapesRegistry()) {
+ final AbstractShape shape = subShape.getShape();
+
+ if (shape instanceof SolidPolygon) {
+ ((SolidPolygon) shape).setColor(color);
+ } else if (shape instanceof Line) {
+ ((Line) shape).color = color;
+ } else if (shape instanceof AbstractCompositeShape) {
+ ((AbstractCompositeShape) shape).setColor(color);
+ }
+ }
+ }
+
+ /**
+ * Assigns a group identifier to all sub-shapes that currently have no group.
+ *
+ * @param groupIdentifier the group to assign to ungrouped shapes
+ */
+ public void setGroupForUngrouped(final String groupIdentifier) {
+ for (final SubShape subShape : subShapesRegistry)
+ if (subShape.isUngrouped())
+ subShape.setGroup(groupIdentifier);
+ }
+
+ @Override
+ public void setMouseInteractionController(
+ final MouseInteractionController mouseInteractionController) {
+ super.setMouseInteractionController(mouseInteractionController);
+
+ for (final SubShape subShape : subShapesRegistry)
+ subShape.getShape().setMouseInteractionController(
+ mouseInteractionController);
+
+ cacheNeedsRebuild = true;
+ }
+
+ /**
+ * Marks this composite as the root scene container.
+ *
+ * <p>Called by {@code ShapeCollection} to configure its root composite.</p>
+ *
+ * @param isRoot {@code true} if this is the root composite, {@code false} otherwise
+ */
+ public void setRootComposite(final boolean isRoot) {
+ this.isRootComposite = isRoot;
+ }
+
+ /**
+ * Returns this composite's transform (position and orientation).
+ *
+ * @return the transform object
+ */
+ public Transform getTransform() {
+ return transform;
+ }
+
+ /**
+ * Sets the transform for this composite shape.
+ *
+ * @param transform the new transform
+ * @return this composite shape (for chaining)
+ */
+ public AbstractCompositeShape setTransform(final Transform transform) {
+ this.transform = transform;
+ return this;
+ }
+
+/**
+ * Sets the cache rebuild flag on this composite and all nested composites recursively.
+ *
+ * <p>Used by {@code ShapeCollection} to trigger a render-list rebuild when
+ * clearing the scene or for other advanced use cases.</p>
+ *
+ * @param needsRebuild {@code true} to force cache rebuild on next frame
+ */
+ public void setCacheNeedsRebuild(final boolean needsRebuild) {
+ this.cacheNeedsRebuild = needsRebuild;
+ // Propagate to nested composites
+ for (final SubShape subShape : subShapesRegistry) {
+ final AbstractShape shape = subShape.getShape();
+ if (shape instanceof AbstractCompositeShape composite) {
+ composite.setCacheNeedsRebuild(needsRebuild);
+ }
+ }
+ }
+
+ /**
+ * Enables or disables shading for all SolidTriangle and SolidPolygon sub-shapes.
+ * When enabled, shapes use the global lighting manager from the rendering
+ * context to calculate flat shading based on light sources.
+ *
+ * <p>Applies recursively to nested {@code AbstractCompositeShape} sub-shapes.</p>
+ *
+ * @param shadingEnabled {@code true} to enable shading, {@code false} to disable
+ * @return this composite shape (for chaining)
+ */
+ public AbstractCompositeShape setShadingEnabled(final boolean shadingEnabled) {
+ for (final SubShape subShape : getSubShapesRegistry()) {
+ final AbstractShape shape = subShape.getShape();
+ if (shape instanceof SolidPolygon) {
+ ((SolidPolygon) shape).setShadingEnabled(shadingEnabled);
+ } else if (shape instanceof AbstractCompositeShape) {
+ ((AbstractCompositeShape) shape).setShadingEnabled(shadingEnabled);
+ }
+ }
+ return this;
+ }
+
+ /**
+ * Enables or disables backface culling for all SolidPolygon and TexturedTriangle sub-shapes.
+ *
+ * <p>Applies recursively to nested {@code AbstractCompositeShape} sub-shapes.</p>
+ *
+ * @param backfaceCulling {@code true} to enable backface culling, {@code false} to disable
+ * @return this composite shape (for chaining)
+ */
+ public AbstractCompositeShape setBackfaceCulling(final boolean backfaceCulling) {
+ for (final SubShape subShape : getSubShapesRegistry()) {
+ final AbstractShape shape = subShape.getShape();
+ if (shape instanceof SolidPolygon) {
+ ((SolidPolygon) shape).setBackfaceCulling(backfaceCulling);
+ } else if (shape instanceof TexturedTriangle) {
+ ((TexturedTriangle) shape).setBackfaceCulling(backfaceCulling);
+ } else if (shape instanceof AbstractCompositeShape) {
+ ((AbstractCompositeShape) shape).setBackfaceCulling(backfaceCulling);
+ }
+ }
+ return this;
+ }
+
+ /**
+ * Performs an in-place union with another composite shape.
+ *
+ * <p>This shape's SolidPolygon children are replaced with the union result.
+ * Non-SolidPolygon children from both shapes are preserved and combined.</p>
+ *
+ * <p><b>CSG Operation:</b> Union combines two shapes into one, keeping all
+ * geometry from both. Uses BSP tree algorithms for robust boolean operations.</p>
+ *
+ * <p><b>Child handling:</b></p>
+ * <ul>
+ * <li>SolidPolygon children from both shapes → replaced with union result</li>
+ * <li>Non-SolidPolygon children from this shape → preserved</li>
+ * <li>Non-SolidPolygon children from other shape → added to this shape</li>
+ * <li>Nested AbstractCompositeShape children → preserved unchanged (not recursively processed)</li>
+ * </ul>
+ *
+ * @param other the shape to union with
+ * @see #subtract(AbstractCompositeShape)
+ * @see #intersect(AbstractCompositeShape)
+ */
+ public void union(final AbstractCompositeShape other) {
+ replaceSolidPolygons(Csg.union(extractSolidPolygons(),
+ other.extractSolidPolygons()));
+ mergeNonPolygonChildrenFrom(other);
+ }
+
+ /**
+ * Performs an in-place subtraction with another composite shape.
+ *
+ * <p>This shape's SolidPolygon children are replaced with the difference result.
+ * The other shape acts as a "cutter" that carves out volume from this shape.</p>
+ *
+ * <p><b>CSG Operation:</b> Subtract removes the volume of the second shape
+ * from the first shape. Useful for creating holes, cavities, and cutouts.</p>
+ *
+ * <p><b>Child handling:</b></p>
+ * <ul>
+ * <li>SolidPolygon children from this shape → replaced with difference result</li>
+ * <li>Non-SolidPolygon children from this shape → preserved</li>
+ * <li>All children from other shape → discarded (other is just a cutter)</li>
+ * <li>Nested AbstractCompositeShape children → preserved unchanged</li>
+ * </ul>
+ *
+ * @param other the shape to subtract (the cutter)
+ * @see #union(AbstractCompositeShape)
+ * @see #intersect(AbstractCompositeShape)
+ */
+ public void subtract(final AbstractCompositeShape other) {
+ replaceSolidPolygons(Csg.subtract(extractSolidPolygons(),
+ other.extractSolidPolygons()));
+ }
+
+ /**
+ * Performs an in-place intersection with another composite shape.
+ *
+ * <p>This shape's SolidPolygon children are replaced with the intersection result.
+ * Only the overlapping volume between the two shapes remains.</p>
+ *
+ * <p><b>CSG Operation:</b> Intersect keeps only the volume where both shapes
+ * overlap. Useful for creating shapes constrained by multiple boundaries.</p>
+ *
+ * <p><b>Child handling:</b></p>
+ * <ul>
+ * <li>SolidPolygon children from this shape → replaced with intersection result</li>
+ * <li>Non-SolidPolygon children from this shape → preserved</li>
+ * <li>All children from other shape → discarded</li>
+ * <li>Nested AbstractCompositeShape children → preserved unchanged</li>
+ * </ul>
+ *
+ * @param other the shape to intersect with
+ * @see #union(AbstractCompositeShape)
+ * @see #subtract(AbstractCompositeShape)
+ */
+ public void intersect(final AbstractCompositeShape other) {
+ replaceSolidPolygons(Csg.intersect(extractSolidPolygons(),
+ other.extractSolidPolygons()));
+ }
+
+ /**
+ * Replaces this shape's SolidPolygon children with new polygons.
+ *
+ * <p>Preserves all non-SolidPolygon children (Lines, nested composites, etc.).</p>
+ *
+ * @param newPolygons the polygons to replace with
+ */
+ private void replaceSolidPolygons(final List<SolidPolygon> newPolygons) {
+ // Remove all direct SolidPolygon children from this shape
+ final Iterator<SubShape> iterator = subShapesRegistry.iterator();
+ while (iterator.hasNext()) {
+ final SubShape subShape = iterator.next();
+ if (subShape.getShape() instanceof SolidPolygon) {
+ iterator.remove();
+ }
+ }
+
+ // Add all result polygons as new children
+ for (final SolidPolygon polygon : newPolygons) {
+ addShape(polygon);
+ }
+
+ cacheNeedsRebuild = true;
+ }
+
+ /**
+ * Merges non-SolidPolygon children from another shape into this shape.
+ *
+ * <p>Copies all non-SolidPolygon children (Lines, nested composites, etc.)
+ * from the other shape, preserving their group identifiers.</p>
+ *
+ * @param other the shape to merge non-polygon children from
+ */
+ private void mergeNonPolygonChildrenFrom(final AbstractCompositeShape other) {
+ if (other == null) {
+ return;
+ }
+
+ for (final SubShape otherSubShape : other.subShapesRegistry) {
+ final AbstractShape otherShape = otherSubShape.getShape();
+ if (!(otherShape instanceof SolidPolygon)) {
+ addShape(otherShape, otherSubShape.getGroupIdentifier());
+ }
+ }
+
+ cacheNeedsRebuild = true;
+ }
+
+ /**
+ * Makes all sub-shapes belonging to the specified group visible.
+ *
+ * @param groupIdentifier the group to show
+ * @see #hideGroup(String)
+ */
+ public void showGroup(final String groupIdentifier) {
+ for (int i = 0; i < subShapesRegistry.size(); i++) {
+ final SubShape subShape = subShapesRegistry.get(i);
+ if (subShape.matchesGroup(groupIdentifier)) {
+ subShape.setVisible(true);
+ cacheNeedsRebuild = true;
+ }
+ }
+ }
+
+ /**
+ * Rebuilds the cached render list from the shape registry:
+ * textured triangles pass through as-is (perspective-correct scanline
+ * rendering needs no tessellation), N-vertex solid polygons are
+ * fan-triangulated, everything else passes through.
+ * Logs the operation to the debug log buffer if available.
+ *
+ * @param context the rendering context for logging, may be {@code null}
+ */
+ private void rebuildRenderList(final RenderingContext context) {
+ cacheNeedsRebuild = false;
+
+ final List<AbstractShape> result = new ArrayList<>();
+ int texturedPolygonCount = 0;
+ int solidPolygonCount = 0;
+ int triangulatedPolygonCount = 0;
+ int otherShapeCount = 0;
+
+ for (int i = 0; i < subShapesRegistry.size(); i++) {
+ final SubShape subShape = subShapesRegistry.get(i);
+ if (!subShape.isVisible())
+ continue;
+
+ final AbstractShape shape = subShape.getShape();
+
+ if (shape instanceof TexturedTriangle) {
+ result.add(shape);
+ texturedPolygonCount++;
+ } else if (shape instanceof SolidPolygon polygon) {
+ final int vertexCount = polygon.getVertexCount();
+
+ if (vertexCount == 3) {
+ result.add(polygon);
+ solidPolygonCount++;
+ } else {
+ triangulateSolidPolygon(polygon, result);
+ triangulatedPolygonCount++;
+ }
+ } else {
+ result.add(shape);
+ otherShapeCount++;
+ }
+ }
+
+ cachedRenderList = postprocessRenderList(result);
+ renderListVersion++;
+ globalRenderListVersion.incrementAndGet();
+
+ if (context != null && context.debugLogBuffer != null) {
+ context.debugLogBuffer.log("rebuildRenderList: " + getClass().getSimpleName()
+ + " texturedPolygons=" + texturedPolygonCount
+ + " solidPolygons=" + solidPolygonCount
+ + " triangulatedPolygons=" + triangulatedPolygonCount
+ + " otherShapes=" + otherShapeCount);
+ }
+ }
+
+ /**
+ * Returns the global render list version: incremented every time ANY
+ * composite's render list is rebuilt. Used by derived structures
+ * (BSP trees, GI scene snapshots) to detect that they must rebuild.
+ *
+ * @return monotonically increasing global version
+ */
+ public static int getGlobalRenderListVersion() {
+ return globalRenderListVersion.get();
+ }
+
+ /**
+ * Collects the triangles of this composite's current render list,
+ * recursing into nested composites. These are the exact objects that
+ * get transformed and rendered: triangulated render-list polygons, or
+ * lightmapped wrappers for
+ * {@link eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.LightmappedCompositeShape}.
+ *
+ * <p>Render lists are built lazily during transform; composites that
+ * have not been transformed yet (or are frustum-culled) contribute
+ * nothing. Vertices are in each composite's local space — callers
+ * combining several composites should require identity transforms.</p>
+ *
+ * @param out list receiving the triangles
+ */
+ public void collectRenderTriangles(final List<AbstractCoordinateShape> out) {
+ if (cachedRenderList == null)
+ return;
+ for (final AbstractShape shape : cachedRenderList) {
+ if (shape instanceof SolidPolygon
+ || shape instanceof eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.texturedpolygon.TexturedTriangle)
+ out.add((AbstractCoordinateShape) shape);
+ else if (shape instanceof AbstractCompositeShape)
+ ((AbstractCompositeShape) shape).collectRenderTriangles(out);
+ }
+ }
+
+ /**
+ * Hook: post-processes the freshly rebuilt render list before it becomes
+ * the rendering cache. The default implementation returns the list
+ * unchanged. Subclasses may replace the list — e.g.
+ * {@link eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.LightmappedCompositeShape}
+ * wraps its polygons into lightmapped triangles here.
+ *
+ * @param renderList the render list built from the shape registry
+ * @return the render list to cache and render
+ */
+ protected List<AbstractShape> postprocessRenderList(final List<AbstractShape> renderList) {
+ return renderList;
+ }
+
+ /**
+ * Triangulates a convex solid polygon using fan triangulation.
+ *
+ * <p>Fan triangulation creates N-2 triangles from an N-vertex polygon by using
+ * vertex 0 as the anchor and connecting it to each adjacent pair of vertices.</p>
+ *
+ * <p>Properties (color, shading, backface culling, mouse interaction) are
+ * propagated to each resulting triangle to ensure consistent behavior.</p>
+ *
+ * @param polygon the polygon to triangulate (must have at least 4 vertices)
+ * @param result the list to add the resulting triangles to
+ */
+ private void triangulateSolidPolygon(final SolidPolygon polygon,
+ final List<AbstractShape> result) {
+
+ final Color color = polygon.getColor();
+ final boolean shadingEnabled = polygon.isShadingEnabled();
+ final boolean backfaceCulling = polygon.isBackfaceCullingEnabled();
+ final MouseInteractionController mouseController = polygon.mouseInteractionController;
+
+ final List<Vertex> vertices = polygon.vertices;
+ final Vertex v0 = vertices.get(0);
+
+ for (int i = 1; i < vertices.size() - 1; i++) {
+ final Vertex v1 = vertices.get(i);
+ final Vertex v2 = vertices.get(i + 1);
+
+ final SolidPolygon triangle = new SolidPolygon(
+ v0.coordinate, v1.coordinate, v2.coordinate, color);
+
+ triangle.setShadingEnabled(shadingEnabled);
+ triangle.setBackfaceCulling(backfaceCulling);
+ triangle.setMouseInteractionController(mouseController);
+
+ result.add(triangle);
+ }
+ }
+
+ @Override
+ public void transform(final TransformStack transformPipe,
+ final RenderAggregator aggregator, final RenderingContext context) {
+
+ // Add the current composite shape transform to the end of the transform
+ // pipeline.
+ transformPipe.addTransform(transform);
+
+ // FRUSTUM CULLING: Check if this composite's bounds are visible
+ // Root composite skips this check (its bounds are always the full scene)
+ // Non-root composites check their aggregated bounds against the frustum
+ if (context.frustum != null && !isRootComposite) {
+ // Count this composite for culling statistics (before frustum test)
+ if (context.cullingStatistics != null) {
+ context.cullingStatistics.totalComposites.incrementAndGet();
+ }
+
+ final Box localBounds = getBoundingBox();
+
+ // Transform all 8 corners of the bounding box to view space
+ final double minX = localBounds.getMinX();
+ final double maxX = localBounds.getMaxX();
+ final double minY = localBounds.getMinY();
+ final double maxY = localBounds.getMaxY();
+ final double minZ = localBounds.getMinZ();
+ final double maxZ = localBounds.getMaxZ();
+
+ final double[] xs = {minX, maxX};
+ final double[] ys = {minY, maxY};
+ final double[] zs = {minZ, maxZ};
+
+ double viewMinX = Double.MAX_VALUE;
+ double viewMaxX = -Double.MAX_VALUE;
+ double viewMinY = Double.MAX_VALUE;
+ double viewMaxY = -Double.MAX_VALUE;
+ double viewMinZ = Double.MAX_VALUE;
+ double viewMaxZ = -Double.MAX_VALUE;
+
+ for (int i = 0; i < 8; i++) {
+ final double x = xs[(i & 1)];
+ final double y = ys[(i >> 1) & 1];
+ final double z = zs[(i >> 2) & 1];
+
+ final Point3D corner = transformPointToViewSpace(x, y, z, transformPipe);
+
+ viewMinX = Math.min(viewMinX, corner.x);
+ viewMaxX = Math.max(viewMaxX, corner.x);
+ viewMinY = Math.min(viewMinY, corner.y);
+ viewMaxY = Math.max(viewMaxY, corner.y);
+ viewMinZ = Math.min(viewMinZ, corner.z);
+ viewMaxZ = Math.max(viewMaxZ, corner.z);
+ }
+
+ final Box viewSpaceBounds = new Box(
+ new Point3D(viewMinX, viewMinY, viewMinZ),
+ new Point3D(viewMaxX, viewMaxY, viewMaxZ)
+ );
+
+ final Frustum frustum = context.frustum;
+ final boolean visible = frustum.intersectsAABB(viewSpaceBounds);
+
+ if (!visible) {
+ // Entire composite outside frustum - skip processing all children
+ if (context.cullingStatistics != null) {
+ context.cullingStatistics.culledComposites.incrementAndGet();
+ }
+ transformPipe.dropTransform();
+ return;
+ }
+ }
+
+ viewSpaceTracker.analyze(transformPipe, context);
+
+ beforeTransformHook(transformPipe, context);
+
+ rebuildRenderListIfNeeded(context);
+
+ // transform rendered subshapes
+ if (shouldForkTransform(context)) {
+ transformChildrenParallel(transformPipe, aggregator, context);
+ } else {
+ transformChildrenSerial(transformPipe, aggregator, context);
+ }
+
+ transformPipe.dropTransform();
+ }
+
+ /**
+ * Minimum number of children before the parallel fork is considered at
+ * all. A single child cannot be split; splitting happens in the child.
+ */
+ private static final int PARALLEL_TRANSFORM_MIN_SHAPES = 2;
+
+ /**
+ * Minimum total subtree weight (leaf primitives below this composite)
+ * before forking its transform into parallel chunks. Below this, the
+ * serial walk is cheaper than the fork overhead. Deliberately above
+ * one sphere's generated triangle count (~960 at 16 segments):
+ * measured 2026-09-04, forking those pays task overhead per chunk for
+ * negligible serial work (35k chunk tasks on a 3000-sphere scene were
+ * SLOWER than serial).
+ */
+ private static final int PARALLEL_TRANSFORM_MIN_SUBTREE_WEIGHT = 2048;
+
+ /**
+ * Minimum weight per parallel chunk task. Keeps chunk granularity
+ * coarse enough that task dispatch overhead stays negligible.
+ */
+ private static final int PARALLEL_TASK_MIN_WEIGHT = 512;
+
+ /**
+ * Cached subtree weight from {@link #getTransformWeight}, valid for
+ * {@link #subtreeWeightCycle} only.
+ */
+ private int cachedSubtreeWeight;
+
+ /**
+ * Transform cycle id the cached subtree weight was computed on.
+ * Keyed on the globally unique cycle id, not the per-context frame
+ * number, so alternating between rendering contexts cannot produce
+ * stale cache hits.
+ */
+ private long subtreeWeightCycle = -1;
+
+ /**
+ * Transform cycle id the cached subtree weight was last RECOMPUTED on.
+ * Separate from {@link #subtreeWeightCycle} (last read): the refresh
+ * gate measures the age of the computation, not of the last access.
+ */
+ private long subtreeWeightComputeCycle = -1;
+
+ /**
+ * {@link #renderListVersion} at the last weight recomputation.
+ */
+ private int weightListVersion = -1;
+
+ /**
+ * Bumped whenever ANY composite rebuilds its render list. Lets the
+ * weight shortcut react to structural changes anywhere in the tree
+ * within one cycle, at O(1) per node per cycle — scanning direct
+ * children's versions instead costs O(leaves) per frame because leaf
+ * lists dominate (measured 2026-09-04: +3-4 ms/frame on a 400-sphere
+ * scene).
+ */
+ private static final AtomicInteger globalRenderListVersion = new AtomicInteger();
+
+ /**
+ * {@link #globalRenderListVersion} value seen at the last weight
+ * recomputation.
+ */
+ private int weightGlobalVersion = -1;
+
+ /**
+ * Bumped every time {@link #cachedRenderList} is rebuilt. Gates weight
+ * recomputation: while the list is unchanged, the cached weight is
+ * reused without re-walking the subtree.
+ */
+ private int renderListVersion;
+
+ /**
+ * Full subtree weight re-walks are O(total leaves below this node),
+ * which costs real milliseconds on big meshes. With an unchanged render
+ * list the cached weight is refreshed at most every this many cycles;
+ * structural changes (rebuilds) recompute immediately.
+ */
+ private static final long WEIGHT_REFRESH_CYCLES = 16;
+
+ /**
+ * Total transform weight of this composite: the sum of its children's
+ * weights, i.e. roughly the number of leaf primitives below it.
+ * Computed lazily; recomputed only when this node's render list was
+ * rebuilt or the cache is older than {@link #WEIGHT_REFRESH_CYCLES}
+ * cycles (children's internal rebuilds are picked up by the periodic
+ * refresh). Used solely for parallel fork load balancing, never for
+ * correctness, so brief staleness is harmless.
+ *
+ * <p>Thread safety: a composite's fork decision runs on exactly one
+ * thread per cycle. Chunk-thread reads are cycle-stamped cache hits
+ * published through the executor's happens-before edge.</p>
+ *
+ * @param renderingContext the rendering context (cycle identity)
+ * @return subtree transform weight, at least 1
+ */
+ @Override
+ public int getTransformWeight(final RenderingContext renderingContext) {
+ final long cycle = renderingContext.transformCycleId;
+ if (subtreeWeightCycle == cycle) {
+ return cachedSubtreeWeight;
+ }
+ final int globalVersion = globalRenderListVersion.get();
+ if (weightListVersion == renderListVersion
+ && weightGlobalVersion == globalVersion
+ && cycle - subtreeWeightComputeCycle < WEIGHT_REFRESH_CYCLES) {
+ // Nothing rebuilt anywhere and computation fresh: keep the
+ // value, just re-stamp the read. O(1) per node per cycle.
+ subtreeWeightCycle = cycle;
+ return cachedSubtreeWeight;
+ }
+ int weight = 0;
+ for (final AbstractShape child : cachedRenderList) {
+ weight += child.getTransformWeight(renderingContext);
+ }
+ cachedSubtreeWeight = Math.max(1, weight);
+ subtreeWeightCycle = cycle;
+ subtreeWeightComputeCycle = cycle;
+ weightListVersion = renderListVersion;
+ weightGlobalVersion = globalVersion;
+ return cachedSubtreeWeight;
+ }
+
+ /**
+ * Decides whether this composite forks its children's transform into
+ * parallel chunks: enough children to split, and enough TOTAL weight
+ * below it to amortize the fork overhead. Weight (not local child
+ * count) is what matters: a deep narrow tree with two heavy children
+ * forks just like a flat mesh with thousands of leaves.
+ *
+ * @param context the rendering context (provides the coordinator)
+ * @return true when the parallel fork should be taken
+ */
+ private boolean shouldForkTransform(final RenderingContext context) {
+ if (context.transformCoordinator == null) {
+ return false;
+ }
+ if (cachedRenderList.size() < PARALLEL_TRANSFORM_MIN_SHAPES) {
+ return false;
+ }
+ return getTransformWeight(context) >= PARALLEL_TRANSFORM_MIN_SUBTREE_WEIGHT;
+ }
+
+ /**
+ * Target number of task chunks per available processor core.
+ * More tasks than cores gives the pool load balancing across
+ * shapes with uneven transform cost.
+ */
+ private static final int PARALLEL_TASKS_PER_CORE = 4;
+
+ /**
+ * Transforms all children serially on the calling thread.
+ *
+ * @param transformPipe the transform stack (includes this composite's transform)
+ * @param aggregator the aggregator to queue visible shapes into
+ * @param context the rendering context
+ */
+ private void transformChildrenSerial(final TransformStack transformPipe,
+ final RenderAggregator aggregator,
+ final RenderingContext context) {
+ for (final AbstractShape shape : cachedRenderList) {
+ shape.transform(transformPipe, aggregator, context);
+ }
+ }
+
+ /**
+ * Forks the children's transform into parallel chunk tasks on the
+ * frame's {@link ParallelTransformCoordinator} and returns immediately
+ * WITHOUT waiting for them.
+ *
+ * <p>Works at any nesting level: a heavy composite reached inside a
+ * chunk task forks its own children into the same coordinator. This is
+ * deadlock-safe because chunk tasks never block on other tasks; only
+ * the orchestrating render thread waits (in the coordinator's drain).</p>
+ *
+ * <p>Stack snapshotting: this composite's transform is dropped from
+ * {@code transformPipe} right after this method returns, long before
+ * the chunk tasks run, so the pipe is copied HERE on the forking
+ * thread. Each task then copies the snapshot for its own working stack.
+ * The snapshot is never mutated after publication, so concurrent
+ * copying by chunk tasks is safe.</p>
+ *
+ * <p>Thread-safety notes: sibling composites are exclusively owned by
+ * one chunk, so their per-instance caches (render list, bounding
+ * boxes, own transform's cached matrix) never race. The vertex
+ * frameNumber cache is a benign race: every thread writes the same
+ * value.</p>
+ *
+ * @param transformPipe the transform stack (includes this composite's transform)
+ * @param aggregator the caller's aggregator, used ONLY when the fork
+ * bails out (too few chunks, or the frame task
+ * budget is exhausted) and the children fall back
+ * to a serial inline transform. The parallel fork
+ * itself queues into per-task aggregators merged
+ * by the coordinator's drain.
+ * @param context the rendering context (provides the coordinator)
+ */
+ private void transformChildrenParallel(final TransformStack transformPipe,
+ final RenderAggregator aggregator,
+ final RenderingContext context) {
+ // Snapshot the render list reference. With the pipelined render
+ // loop, the NEXT pass's tree walk can already be running while
+ // this pass's chunk tasks are still queued (the drain happens in
+ // the async continuation, not before the next walk). That walk
+ // may rebuild this composite's render list, REASSIGNING
+ // cachedRenderList to a new list of a different size. The chunk
+ // ranges below are computed against this list instance, so the
+ // chunk tasks must index this same instance — re-reading the
+ // field inside the lambda raced with the rebuild and threw
+ // IndexOutOfBoundsException. (The old list stays alive and valid
+ // for this pass; each pass transforms into its own vertex slot.)
+ final List<AbstractShape> renderList = cachedRenderList;
+ final int size = renderList.size();
+ final int totalWeight = getTransformWeight(context);
+ final int processors = Runtime.getRuntime().availableProcessors();
+ final int targetTasks = processors * PARALLEL_TASKS_PER_CORE;
+ final int taskWeight = Math.max(PARALLEL_TASK_MIN_WEIGHT,
+ (totalWeight + targetTasks - 1) / targetTasks);
+
+ // Pass 1: count chunks, cutting by ACCUMULATED WEIGHT so that a
+ // node with few but heavy children (e.g. two 25k-triangle halves
+ // of a fractal) still splits into multiple tasks
+ int taskCount = 0;
+ int accumulated = 0;
+ for (int i = 0; i < size; i++) {
+ accumulated += renderList.get(i).getTransformWeight(context);
+ if (accumulated >= taskWeight) {
+ taskCount++;
+ accumulated = 0;
+ }
+ }
+ if (accumulated > 0) {
+ taskCount++;
+ }
+
+ if (taskCount < 2) {
+ transformChildrenSerial(transformPipe, aggregator, context);
+ return;
+ }
+
+ final ParallelTransformCoordinator coordinator = context.transformCoordinator;
+ if (!coordinator.tryReserveTasks(taskCount)) {
+ // Frame-wide task budget exhausted: transform inline
+ transformChildrenSerial(transformPipe, aggregator, context);
+ return;
+ }
+
+ final TransformStack snapshot = new TransformStack(transformPipe);
+
+ // Pass 2: submit chunks (weights are frame-cached, cheap re-walk)
+ int from = 0;
+ accumulated = 0;
+ for (int i = 0; i < size; i++) {
+ accumulated += renderList.get(i).getTransformWeight(context);
+ if (accumulated >= taskWeight || i == size - 1) {
+ final int chunkFrom = from;
+ final int chunkTo = i + 1;
+ coordinator.submit(() -> {
+ // Pooled scratch: the stack (9.6 KB of arrays) and
+ // the chunk aggregator (queue keeps its capacity
+ // across frames) come from the coordinator's static
+ // pools — previously each chunk allocated both on
+ // every frame.
+ final TransformStack taskStack =
+ coordinator.borrowStack(snapshot);
+ try {
+ final RenderAggregator taskAggregator =
+ coordinator.borrowAggregator();
+ for (int c = chunkFrom; c < chunkTo; c++) {
+ renderList.get(c).transform(taskStack, taskAggregator, context);
+ }
+ return taskAggregator;
+ } finally {
+ coordinator.returnStack(taskStack);
+ }
+ });
+ from = i + 1;
+ accumulated = 0;
+ }
+ }
+ }
+
+ /**
+ * Transforms a point to view space using the current transform stack.
+ * Helper method for frustum culling that transforms bounding box corners.
+ *
+ * @param x the X coordinate in local space
+ * @param y the Y coordinate in local space
+ * @param z the Z coordinate in local space
+ * @param transformPipe the current transform stack
+ * @return the transformed point in view space
+ */
+ private Point3D transformPointToViewSpace(final double x, final double y, final double z,
+ final TransformStack transformPipe) {
+ final Point3D input = new Point3D(x, y, z);
+ final Point3D result = new Point3D();
+ transformPipe.transform(input, result);
+ return result;
+ }
+
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base;
+
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon.SolidPolygon;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * A Binary Space Partitioning (BSP) tree for CSG operations.
+ *
+ * <p>BSP trees are the data structure that makes CSG boolean operations possible.
+ * Each node divides 3D space into two half-spaces using a plane, enabling
+ * efficient spatial queries and polygon clipping.</p>
+ *
+ * <p><b>BSP Tree Structure:</b></p>
+ * <pre>
+ * [Node: plane P]
+ * / \
+ * [Front subtree] [Back subtree]
+ * (same side as P's (opposite side
+ * normal) of P's normal)
+ * </pre>
+ *
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape
+ * @see Plane the plane type used for spatial partitioning
+ * @see SolidPolygon the polygon type stored in BSP nodes
+ */
+public class BspTree {
+
+ /**
+ * Polygons that lie on this node's partitioning plane.
+ */
+ public final List<SolidPolygon> polygons = new ArrayList<>();
+
+ /**
+ * The partitioning plane for this node.
+ */
+ public Plane plane;
+
+ /**
+ * The front child subtree.
+ */
+ public BspTree front;
+
+ /**
+ * The back child subtree.
+ */
+ public BspTree back;
+
+ /**
+ * Creates an empty BSP tree with no plane or children.
+ */
+ public BspTree() {
+ }
+
+ /**
+ * Creates a BSP tree from a list of polygons.
+ *
+ * @param polygons the polygons to partition into a BSP tree
+ */
+ public BspTree(final List<SolidPolygon> polygons) {
+ addPolygons(polygons);
+ }
+
+ /**
+ * Creates a deep clone of this BSP tree.
+ *
+ * @return a new BspTree with cloned data
+ */
+ public BspTree clone() {
+ final BspTree tree = new BspTree();
+
+ tree.plane = plane != null ? plane.clone() : null;
+ tree.front = front != null ? front.clone() : null;
+ tree.back = back != null ? back.clone() : null;
+
+ for (final SolidPolygon p : polygons) {
+ tree.polygons.add(p.deepClone());
+ }
+
+ return tree;
+ }
+
+ /**
+ * Inverts this BSP tree, converting "inside" to "outside" and vice versa.
+ */
+ public void invert() {
+ for (final SolidPolygon polygon : polygons) polygon.flip();
+
+ if (plane != null) plane.flip();
+ if (front != null) front.invert();
+ if (back != null) back.invert();
+
+ final BspTree temp = front;
+ front = back;
+ back = temp;
+ }
+
+ /**
+ * Clips a list of polygons against this BSP tree, returning only the
+ * portions that lie outside the solid represented by this tree.
+ *
+ * <p>This is a core CSG operation used for boolean subtraction and
+ * intersection. The method recursively traverses the BSP tree, splitting
+ * polygons at each partitioning plane and discarding interior fragments.</p>
+ *
+ * <p><b>Algorithm:</b></p>
+ * <ol>
+ * <li>At each node, split polygons by the partitioning plane</li>
+ * <li>Recursively clip front fragments against the front subtree</li>
+ * <li>Recursively clip back fragments against the back subtree</li>
+ * <li>Combine and return all surviving fragments</li>
+ * </ol>
+ *
+ * <p><b>Leaf nodes:</b> If this node has no plane (leaf node), all polygons
+ * are considered outside and returned unchanged.</p>
+ *
+ * @param polygons the polygons to clip against this BSP tree
+ * @return a new list containing only the portions outside this solid
+ */
+ public List<SolidPolygon> clipPolygons(final List<SolidPolygon> polygons) {
+ // Leaf node: no partitioning plane means all polygons are outside
+ if (plane == null) {
+ return new ArrayList<>(polygons);
+ }
+
+ // Split polygons by this node's partitioning plane
+ final List<SolidPolygon> frontList = new ArrayList<>();
+ final List<SolidPolygon> backList = new ArrayList<>();
+
+ for (final SolidPolygon polygon : polygons)
+ // Split by plane: coplanar polygons are classified by their normal direction
+ // (same-facing normal → frontList, opposite-facing normal → backList)
+ plane.splitPolygon(polygon, frontList, backList, frontList, backList);
+
+ // Recursively clip front fragments against front subtree
+ List<SolidPolygon> resultFront = frontList;
+ if (front != null) resultFront = front.clipPolygons(frontList);
+
+ // Recursively clip back fragments against back subtree
+ List<SolidPolygon> resultBack;
+ if (back != null) resultBack = back.clipPolygons(backList);
+ else resultBack = new ArrayList<>();
+
+ // Combine surviving fragments from both subtrees
+ final List<SolidPolygon> result = new ArrayList<>(resultFront.size() + resultBack.size());
+ result.addAll(resultFront);
+ result.addAll(resultBack);
+ return result;
+ }
+
+ /**
+ * Clips this BSP tree against another BSP tree.
+ *
+ * @param bsp the BSP tree to clip against
+ */
+ public void clipTo(final BspTree bsp) {
+ final List<SolidPolygon> newPolygons = bsp.clipPolygons(polygons);
+ polygons.clear();
+ polygons.addAll(newPolygons);
+
+ if (front != null) front.clipTo(bsp);
+ if (back != null) back.clipTo(bsp);
+ }
+
+ /**
+ * Collects all polygons from this BSP tree into a flat list.
+ *
+ * @return a new list containing all polygons in this tree
+ */
+ public List<SolidPolygon> allPolygons() {
+ final List<SolidPolygon> result = new ArrayList<>(polygons);
+
+ if (front != null) result.addAll(front.allPolygons());
+ if (back != null) result.addAll(back.allPolygons());
+
+ return result;
+ }
+
+ /**
+ * Adds polygons to this BSP tree, partitioning space recursively.
+ *
+ * <p>This method is the core BSP tree construction algorithm. It builds or
+ * extends the tree by choosing a partition plane and classifying each polygon:</p>
+ *
+ * <ul>
+ * <li><b>Coplanar</b> — polygons on the partition plane are stored in this node</li>
+ * <li><b>Front</b> — polygons in the front half-space (same side as plane normal)
+ * go to the front child subtree</li>
+ * <li><b>Back</b> — polygons in the back half-space (opposite to plane normal)
+ * go to the back child subtree</li>
+ * <li><b>Spanning</b> — polygons crossing the plane are split into front and back
+ * fragments, each going to its respective subtree</li>
+ * </ul>
+ *
+ * <p>For an empty tree, the first polygon's plane becomes the partition plane.
+ * Child nodes are created lazily when polygons need to be stored in them.</p>
+ *
+ * <p>Can be called multiple times to incrementally extend an existing tree,
+ * though the original partition planes remain unchanged.</p>
+ *
+ * @param polygons the polygons to insert into this BSP tree
+ * @see Plane#splitPolygon the method that classifies and splits individual polygons
+ */
+ public void addPolygons(final List<SolidPolygon> polygons) {
+ if (polygons.isEmpty()) return;
+
+ if (plane == null) plane = polygons.get(0).getPlane().clone();
+
+ final List<SolidPolygon> frontList = new ArrayList<>();
+ final List<SolidPolygon> backList = new ArrayList<>();
+
+ for (final SolidPolygon polygon : polygons)
+ plane.splitPolygon(polygon, this.polygons, this.polygons, frontList, backList);
+
+ if (!frontList.isEmpty()) {
+ if (front == null) front = new BspTree();
+ front.addPolygons(frontList);
+ }
+
+ if (!backList.isEmpty()) {
+ if (back == null) back = new BspTree();
+ back.addPolygons(backList);
+ }
+ }
+}
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base;
+
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon.SolidPolygon;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Pure CSG (Constructive Solid Geometry) boolean engine: union, subtract
+ * and intersect over lists of {@link SolidPolygon}s, built on BSP tree
+ * clip/invert sequences.
+ *
+ * <p>These are pure functions — they take polygon lists and return new
+ * polygon lists, touching no shape state. {@link AbstractCompositeShape}'s
+ * instance methods ({@code union/subtract/intersect}) delegate here and
+ * handle the child-registry bookkeeping themselves.</p>
+ *
+ * <p>All operations clone their inputs first (BSP operations mutate
+ * polygons in place), so caller lists are never modified.</p>
+ */
+public final class Csg {
+
+ private Csg() {
+ // utility class
+ }
+
+ /**
+ * Union of two polygon sets: every surface of both, interior faces
+ * removed.
+ *
+ * @param a first operand's polygons (not modified)
+ * @param b second operand's polygons (not modified)
+ * @return the union result polygons
+ */
+ public static List<SolidPolygon> union(final List<SolidPolygon> a,
+ final List<SolidPolygon> b) {
+ // Degenerate operands: the BSP sequence handles these, but the
+ // short-circuit is explicit (and skips the tree builds).
+ if (a.isEmpty()) return clonePolygons(b);
+ if (b.isEmpty()) return clonePolygons(a);
+
+ final BspTree selfTree = new BspTree(clonePolygons(a));
+ final BspTree otherTree = new BspTree(clonePolygons(b));
+
+ // Remove from self any polygons that are inside other (interior faces)
+ selfTree.clipTo(otherTree);
+
+ // Remove from other any polygons that are inside self (interior faces)
+ otherTree.clipTo(selfTree);
+
+ // Invert other to convert remaining polygons for the next clip step
+ otherTree.invert();
+
+ // Clip inverted other against self to remove back-facing coplanar polygons
+ otherTree.clipTo(selfTree);
+
+ // Invert back to restore correct polygon orientation
+ otherTree.invert();
+
+ // Merge other's remaining polygons into self's BSP tree
+ selfTree.addPolygons(otherTree.allPolygons());
+
+ return selfTree.allPolygons();
+ }
+
+ /**
+ * Subtraction {@code a - b}: the cutter volume carved out of the
+ * target.
+ *
+ * @param a target polygons (not modified)
+ * @param b cutter polygons (not modified)
+ * @return the difference result polygons
+ */
+ public static List<SolidPolygon> subtract(final List<SolidPolygon> a,
+ final List<SolidPolygon> b) {
+ if (a.isEmpty() || b.isEmpty()) return clonePolygons(a);
+
+ final BspTree target = new BspTree(clonePolygons(a));
+ final BspTree cutter = new BspTree(clonePolygons(b));
+
+ // Invert target: convert "inside" to "outside" and vice versa
+ // This transforms the problem from "subtract B from A" to "intersect A's complement with B's complement"
+ target.invert();
+
+ // Clip target against cutter: removes parts of target that are INSIDE the cutter
+ // Since target is inverted, this removes parts that were OUTSIDE the original target
+ target.clipTo(cutter);
+
+ // Clip cutter against (inverted) target: removes parts of cutter outside the inverted target
+ // This keeps only cutter polygons that are inside the inverted target = outside original target
+ cutter.clipTo(target);
+
+ // Invert cutter to flip its inside/outside
+ cutter.invert();
+
+ // Clip inverted cutter against target: removes coplanar back-faces
+ cutter.clipTo(target);
+
+ // Invert cutter back to correct orientation
+ cutter.invert();
+
+ // Merge cutter's polygons into target's BSP tree
+ target.addPolygons(cutter.allPolygons());
+
+ // Invert target back to restore correct inside/outside orientation
+ // Result: the carved-out volume (target minus cutter)
+ target.invert();
+
+ return target.allPolygons();
+ }
+
+ /**
+ * Intersection of two polygon sets: only the overlapping volume
+ * remains.
+ *
+ * @param a first operand's polygons (not modified)
+ * @param b second operand's polygons (not modified)
+ * @return the intersection result polygons
+ */
+ public static List<SolidPolygon> intersect(final List<SolidPolygon> a,
+ final List<SolidPolygon> b) {
+ // Degenerate operand: the classic BSP sequence returns A here
+ // (an empty tree classifies nothing as inside, so every clip is
+ // a no-op and the inverts cancel out) — but the intersection
+ // with an empty volume IS empty. Guard explicitly.
+ if (a.isEmpty() || b.isEmpty()) return List.of();
+
+ final BspTree selfTree = new BspTree(clonePolygons(a));
+ final BspTree otherTree = new BspTree(clonePolygons(b));
+
+ // Invert self to convert "inside" to "outside"
+ // This transforms intersection into: keep parts that are "outside both inverted shapes"
+ selfTree.invert();
+
+ // Clip other against inverted self: keeps only parts of other that are INSIDE original self
+ // (because clipTo removes what's "outside" the BSP, and inverted self's "outside" = original self's "inside")
+ otherTree.clipTo(selfTree);
+
+ // Invert other (which now represents the intersection region)
+ otherTree.invert();
+
+ // Clip inverted self against (inverted intersection): removes parts outside the intersection
+ selfTree.clipTo(otherTree);
+
+ // Clip intersection result against inverted self: removes back-facing coplanar polygons
+ otherTree.clipTo(selfTree);
+
+ // Build final BSP tree from the clipped intersection polygons
+ selfTree.addPolygons(otherTree.allPolygons());
+
+ // Invert back to restore correct inside/outside orientation
+ selfTree.invert();
+
+ return selfTree.allPolygons();
+ }
+
+ /**
+ * Deep clones of all polygons in the list: CSG operations modify
+ * polygons in-place via BSP tree operations, cloning preserves the
+ * originals.
+ */
+ private static List<SolidPolygon> clonePolygons(final List<SolidPolygon> polygons) {
+ final List<SolidPolygon> cloned = new ArrayList<>(polygons.size());
+ for (final SolidPolygon p : polygons) {
+ cloned.add(p.deepClone());
+ }
+ return cloned;
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base;
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+
+import eu.svjatoslav.aukio.e3d.renderer.raster.Vertex;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon.SolidPolygon;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Represents an infinite plane in 3D space using the Hesse normal form.
+ *
+ * <p>Planes are fundamental to BSP (Binary Space Partitioning) tree operations
+ * in CSG. They divide 3D space into two half-spaces.</p>
+ *
+ * @see SolidPolygon polygons that reference their containing plane
+ * @see BspTree BSP trees that use planes for spatial partitioning
+ */
+public class Plane {
+
+ /**
+ * Epsilon value used for floating-point comparisons in BSP operations.
+ * Smaller values provide higher precision but may cause issues with
+ * near-coplanar polygons. 1e-5 is a good balance for most 3D geometry.
+ */
+ public static final double EPSILON = 1e-12;
+
+ /**
+ * The unit normal vector perpendicular to the plane surface.
+ */
+ public Point3D normal;
+
+ /**
+ * The signed distance from the origin to the plane along the normal.
+ */
+ public double distance;
+
+ /**
+ * Creates a plane with the given normal and distance.
+ *
+ * @param normal the unit normal vector
+ * @param distance the signed distance from origin to the plane
+ */
+ public Plane(final Point3D normal, final double distance) {
+ this.normal = normal;
+ this.distance = distance;
+ }
+
+ /**
+ * Computes the unit normal vector for a triangle defined by three points.
+ *
+ * <p>Zero-allocation method: fills the result point instead of creating a new one.
+ * This is the shared implementation used by both {@link #fromPoints} and
+ * {@link SolidPolygon} for shading calculations.</p>
+ *
+ * <p>The normal is computed as the cross product of two edge vectors (b-a and c-a),
+ * then normalized to unit length.</p>
+ *
+ * @param a first point (base point for edge vectors)
+ * @param b second point
+ * @param c third point
+ * @param result Point3D to receive the unit normal vector (modified in place)
+ * @return true if normal computed successfully, false if points are collinear
+ * (cross product magnitude less than EPSILON)
+ */
+ public static boolean computeNormal(final Point3D a, final Point3D b,
+ final Point3D c, final Point3D result) {
+ // Edge vectors from a to b and a to c
+ final double ax = b.x - a.x;
+ final double ay = b.y - a.y;
+ final double az = b.z - a.z;
+
+ final double bx = c.x - a.x;
+ final double by = c.y - a.y;
+ final double bz = c.z - a.z;
+
+ // Cross product: (edge1 × edge2)
+ double nx = ay * bz - az * by;
+ double ny = az * bx - ax * bz;
+ double nz = ax * by - ay * bx;
+
+ // Normalize
+ final double length = Math.sqrt(nx * nx + ny * ny + nz * nz);
+ if (length < EPSILON) {
+ result.x = result.y = result.z = 0;
+ return false;
+ }
+
+ result.x = nx / length;
+ result.y = ny / length;
+ result.z = nz / length;
+ return true;
+ }
+
+ /**
+ * Creates a plane from three non-collinear points.
+ *
+ * <p>Uses {@link #computeNormal} for the normal calculation, then computes
+ * the signed distance from origin using the dot product.</p>
+ *
+ * @param a the first point on the plane
+ * @param b the second point on the plane
+ * @param c the third point on the plane
+ * @return a new Plane passing through the three points
+ * @throws ArithmeticException if the points are collinear (cannot define a plane)
+ */
+ public static Plane fromPoints(final Point3D a, final Point3D b, final Point3D c) {
+ final Point3D n = new Point3D();
+ if (!computeNormal(a, b, c, n)) {
+ throw new ArithmeticException(
+ "Cannot create plane from collinear points: cross product is zero");
+ }
+ return new Plane(n, n.dot(a));
+ }
+
+ /**
+ * Creates a deep clone of this plane.
+ *
+ * @return a new Plane with the same normal and distance
+ */
+ public Plane clone() {
+ return new Plane(new Point3D(normal.x, normal.y, normal.z), distance);
+ }
+
+ /**
+ * Flips the plane orientation by negating the normal and distance.
+ */
+ public void flip() {
+ normal = normal.withNegated();
+ distance = -distance;
+ }
+
+ /**
+ * Splits a polygon by this plane, classifying and potentially dividing it.
+ *
+ * @param polygon the polygon to classify and potentially split
+ * @param coplanarFront list to receive coplanar polygons with same-facing normals
+ * @param coplanarBack list to receive coplanar polygons with opposite-facing normals
+ * @param front list to receive polygons in the front half-space
+ * @param back list to receive polygons in the back half-space
+ */
+ public void splitPolygon(final SolidPolygon polygon,
+ final List<SolidPolygon> coplanarFront,
+ final List<SolidPolygon> coplanarBack,
+ final List<SolidPolygon> front,
+ final List<SolidPolygon> back) {
+
+ PolygonType polygonType = PolygonType.COPLANAR;
+ final int vertexCount = polygon.getVertexCount();
+ final PolygonType[] types = new PolygonType[vertexCount];
+
+ for (int i = 0; i < vertexCount; i++) {
+ final Vertex v = polygon.vertices.get(i);
+ final double t = normal.dot(v.coordinate) - distance;
+ final PolygonType type = (t < -EPSILON) ? PolygonType.BACK
+ : (t > EPSILON) ? PolygonType.FRONT : PolygonType.COPLANAR;
+ polygonType = polygonType.combine(type);
+ types[i] = type;
+ }
+
+ switch (polygonType) {
+ case COPLANAR:
+ ((normal.dot(polygon.getPlane().normal) > 0) ? coplanarFront : coplanarBack).add(polygon);
+ break;
+
+ case FRONT:
+ front.add(polygon);
+ break;
+
+ case BACK:
+ back.add(polygon);
+ break;
+
+ case SPANNING:
+ // Split spanning polygon by clipping each edge against the plane.
+ // Vertices on each side go to their respective lists.
+ // Edges crossing the plane create intersection vertices added to both lists.
+ final List<Vertex> frontVertices = new ArrayList<>();
+ final List<Vertex> backVertices = new ArrayList<>();
+
+ for (int i = 0; i < vertexCount; i++) {
+ final int nextIndex = (i + 1) % vertexCount;
+ final PolygonType currentType = types[i];
+ final PolygonType nextType = types[nextIndex];
+ final Vertex currentVertex = polygon.vertices.get(i);
+ final Vertex nextVertex = polygon.vertices.get(nextIndex);
+
+ // Add current vertex to the polygon on its side of the plane
+ if (currentType.isFront()) {
+ frontVertices.add(currentVertex.clone());
+ }
+ if (currentType.isBack()) {
+ backVertices.add(currentVertex.clone());
+ }
+
+ // If edge crosses the plane, create intersection vertex for both polygons
+ if (currentType != nextType
+ && currentType != PolygonType.COPLANAR
+ && nextType != PolygonType.COPLANAR) {
+ // Calculate interpolation parameter t (0 = current, 1 = next)
+ // t represents where along the edge the plane intersection occurs
+ final double t = (distance - normal.dot(currentVertex.coordinate))
+ / normal.dot(nextVertex.coordinate.withSubtracted(currentVertex.coordinate));
+
+ final Vertex intersectionVertex = currentVertex.interpolate(nextVertex, t);
+ frontVertices.add(intersectionVertex);
+ backVertices.add(intersectionVertex.clone());
+ }
+ }
+
+ if (frontVertices.size() >= 3) {
+ final SolidPolygon frontPoly = SolidPolygon.fromVertices(
+ frontVertices, polygon.getColor(), polygon.isShadingEnabled());
+ front.add(frontPoly);
+ }
+ if (backVertices.size() >= 3) {
+ final SolidPolygon backPoly = SolidPolygon.fromVertices(
+ backVertices, polygon.getColor(), polygon.isShadingEnabled());
+ back.add(backPoly);
+ }
+ break;
+ }
+ }
+}
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base;
+
+/**
+ * Classification of a polygon's position relative to a plane.
+ * Used in BSP tree operations to determine how polygons should be split.
+ */
+public enum PolygonType {
+ /** Polygon lies on the plane. */
+ COPLANAR,
+ /** Polygon is entirely in front of the plane. */
+ FRONT,
+ /** Polygon is entirely behind the plane. */
+ BACK,
+ /** Polygon straddles the plane (vertices on both sides). */
+ SPANNING;
+
+ /**
+ * Combines this type with another to compute the aggregate classification.
+ * When vertices are on both sides of a plane, the result is SPANNING.
+ *
+ * @param other the other polygon type to combine with
+ * @return the combined classification
+ */
+ public PolygonType combine(final PolygonType other) {
+ if (this == other || other == COPLANAR) {
+ return this;
+ }
+ if (this == COPLANAR) {
+ return other;
+ }
+ // FRONT + BACK = SPANNING
+ return SPANNING;
+ }
+
+ /**
+ * Checks if this type represents a vertex in front of the plane.
+ *
+ * @return true if FRONT or COPLANAR (treated as front for classification)
+ */
+ public boolean isFront() {
+ return this == FRONT || this == COPLANAR;
+ }
+
+ /**
+ * Checks if this type represents a vertex behind the plane.
+ *
+ * @return true if BACK or COPLANAR (treated as back for classification)
+ */
+ public boolean isBack() {
+ return this == BACK || this == COPLANAR;
+ }
+}
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base;
+
+import java.util.Objects;
+
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.AbstractShape;
+
+/**
+ * Wrapper around an {@link AbstractShape} within an {@link AbstractCompositeShape},
+ * adding group membership and visibility control.
+ *
+ * <p>Sub-shapes can be organized into named groups so they can be shown, hidden,
+ * or removed together. This is useful for toggling parts of a composite shape,
+ * such as showing/hiding labels, highlights, or selection borders.</p>
+ *
+ * @see AbstractCompositeShape#addShape(AbstractShape, String)
+ * @see AbstractCompositeShape#hideGroup(String)
+ * @see AbstractCompositeShape#showGroup(String)
+ */
+public class SubShape {
+
+ /**
+ * The wrapped shape that belongs to the parent composite shape.
+ * This is the actual renderable geometry (line, polygon, etc.).
+ */
+ private final AbstractShape shape;
+
+ /**
+ * Whether this sub-shape should be rendered.
+ * Hidden shapes remain in the composite but are excluded from rendering.
+ */
+ private boolean visible = true;
+
+ /**
+ * The group identifier for batch visibility operations.
+ * {@code null} indicates this shape is not part of any named group.
+ */
+ private String groupIdentifier;
+
+ /**
+ * Creates a sub-shape wrapper around the given shape with default visibility (visible).
+ *
+ * @param shape the shape to wrap
+ */
+ public SubShape(final AbstractShape shape) {
+ this(shape, null, true);
+ }
+
+ /**
+ * Creates a sub-shape with all properties specified.
+ *
+ * @param shape the shape to wrap
+ * @param groupIdentifier the group identifier, or {@code null} for ungrouped
+ * @param visible whether the shape is initially visible
+ */
+ public SubShape(final AbstractShape shape, final String groupIdentifier, final boolean visible) {
+ this.shape = shape;
+ this.groupIdentifier = groupIdentifier;
+ this.visible = visible;
+ }
+
+ /**
+ * Returns {@code true} if this sub-shape has no group assigned.
+ *
+ * @return {@code true} if ungrouped
+ */
+ public boolean isUngrouped() {
+ return groupIdentifier == null;
+ }
+
+ /**
+ * Checks whether this sub-shape belongs to the specified group.
+ *
+ * @param groupIdentifier the group identifier to match against, or {@code null} to match ungrouped shapes
+ * @return {@code true} if this sub-shape belongs to the specified group
+ */
+ public boolean matchesGroup(final String groupIdentifier) {
+ return Objects.equals(this.groupIdentifier, groupIdentifier);
+ }
+
+ /**
+ * Returns the group identifier for this sub-shape.
+ *
+ * @return the group identifier, or {@code null} if this shape is ungrouped
+ */
+ public String getGroupIdentifier() {
+ return groupIdentifier;
+ }
+
+ /**
+ * Assigns this sub-shape to a group.
+ *
+ * @param groupIdentifier the group identifier, or {@code null} to make it ungrouped
+ */
+ public void setGroup(final String groupIdentifier) {
+ this.groupIdentifier = groupIdentifier;
+ }
+
+ /**
+ * Returns the wrapped shape.
+ *
+ * @return the underlying shape
+ */
+ public AbstractShape getShape() {
+ return shape;
+ }
+
+ /**
+ * Returns whether this sub-shape is currently visible and will be rendered.
+ *
+ * @return {@code true} if visible
+ */
+ public boolean isVisible() {
+ return visible;
+ }
+
+ /**
+ * Sets the visibility of this sub-shape.
+ *
+ * @param visible {@code true} to make the shape visible, {@code false} to hide it
+ */
+ public void setVisible(boolean visible) {
+ this.visible = visible;
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+
+/**
+ * Base class and utilities for composite shapes.
+ *
+ * <p>{@link eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape}
+ * is the foundation for building complex 3D objects by grouping primitives.</p>
+ *
+ * <p>Features:</p>
+ * <ul>
+ * <li>Position and rotation in 3D space</li>
+ * <li>Named groups for selective visibility</li>
+ * <li>Automatic sub-shape management</li>
+ * <li>Integration with lighting and slicing</li>
+ * </ul>
+ *
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.SubShape
+ */
+
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base;
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+
+/**
+ * Composite shapes that group multiple primitives into compound 3D objects.
+ *
+ * <p>Composite shapes allow building complex objects from simpler primitives.
+ * They support grouping, visibility toggling, and hierarchical transformations.</p>
+ *
+ * <p>Subpackages:</p>
+ * <ul>
+ * <li>{@code base} - Base class for all composite shapes</li>
+ * <li>{@code solid} - Solid objects (cubes, spheres, cylinders)</li>
+ * <li>{@code wireframe} - Wireframe objects (boxes, grids, spheres)</li>
+ * <li>{@code textcanvas} - 3D text rendering canvas</li>
+ * </ul>
+ *
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape
+ */
+
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite;
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.solid;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.math.Matrix3x3;
+import eu.svjatoslav.aukio.e3d.math.Quaternion;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon.SolidPolygon;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape;
+
+/**
+ * A 3D arrow shape composed of a cylindrical body and a conical tip.
+ *
+ * <p>The arrow points from a start point to an end point, with the tip
+ * located at the end point. The arrow's appearance (size, color, transparency)
+ * can be customized through the constructor parameters.</p>
+ *
+ * <p><b>Usage example:</b></p>
+ * <pre>{@code
+ * // Create a red arrow pointing from origin to (100, -50, 200)
+ * SolidPolygonArrow arrow = new SolidPolygonArrow(
+ * new Point3D(0, 0, 0), // start point
+ * new Point3D(100, -50, 200), // end point
+ * 8, // body radius
+ * 20, // tip radius
+ * 40, // tip length
+ * 16, // segments
+ * Color.RED // color
+ * );
+ * shapeCollection.addShape(arrow);
+ *
+ * // Create a semi-transparent blue arrow
+ * SolidPolygonArrow seeThroughArrow = new SolidPolygonArrow(
+ * new Point3D(0, 100, 0),
+ * new Point3D(0, -100, 0),
+ * 10, 25, 50, 12,
+ * new Color(0, 0, 255, 128) // blue with 50% transparency
+ * );
+ * }</pre>
+ *
+ * @see SolidPolygonCone
+ * @see SolidPolygonCylinder
+ */
+public class SolidPolygonArrow extends AbstractCompositeShape {
+
+ /**
+ *
+ * Number of segments for arrow smoothness.
+ */
+ private static final int SEGMENTS = 12;
+
+ /**
+ * Arrow tip radius as a fraction of body radius (2.5x).
+ */
+ private static final double TIP_RADIUS_FACTOR = 2.5;
+
+ /**
+ * Arrow tip length as a fraction of body radius (5.0x).
+ */
+ private static final double TIP_LENGTH_FACTOR = 5.0;
+
+ /**
+ * Constructs a 3D arrow pointing from start to end with sensible defaults.
+ *
+ * <p>This simplified constructor automatically calculates the tip radius as
+ * 2.5 times the body radius, the tip length as 5 times the body radius, and
+ * uses 12 segments for smoothness. For custom tip dimensions or segment count,
+ * use the full constructor.</p>
+ *
+ * @param startPoint the origin point of the arrow (where the body starts)
+ * @param endPoint the destination point of the arrow (where the tip points to)
+ * @param bodyRadius the radius of the cylindrical body; tip dimensions are
+ * calculated automatically from this value
+ * @param color the fill color (RGBA; alpha controls transparency)
+ */
+ public SolidPolygonArrow(final Point3D startPoint, final Point3D endPoint,
+ final double bodyRadius, final Color color) {
+ super();
+
+ // Calculate direction and distance
+ final double dx = endPoint.x - startPoint.x;
+ final double dy = endPoint.y - startPoint.y;
+ final double dz = endPoint.z - startPoint.z;
+ final double distance = Math.sqrt(dx * dx + dy * dy + dz * dz);
+
+ // Handle degenerate case: start and end are the same point
+ if (distance < 0.001) {
+ return;
+ }
+
+ // Normalize direction vector
+ final double nx = dx / distance;
+ final double ny = dy / distance;
+ final double nz = dz / distance;
+
+ // Calculate rotation to align Y-axis with direction
+ // Default arrow points in -Y direction (apex at lower Y)
+ // We need to rotate from (0, -1, 0) to (nx, ny, nz)
+ final Quaternion rotation = createRotationFromYAxis(nx, ny, nz);
+ final Matrix3x3 rotMatrix = rotation.toMatrix();
+
+ // Calculate body length (distance minus tip)
+ final double bodyLength = Math.max(0, distance - bodyRadius * TIP_LENGTH_FACTOR);
+
+ // Build the arrow components
+ if (bodyLength > 0) {
+ addCylinderBody(startPoint, bodyRadius, bodyLength, SEGMENTS, color, rotMatrix, nx, ny, nz);
+ }
+ addConeTip(endPoint, bodyRadius * TIP_RADIUS_FACTOR, bodyRadius * TIP_LENGTH_FACTOR, SEGMENTS, color, rotMatrix, nx, ny, nz);
+
+ setBackfaceCulling(true);
+ }
+
+ /**
+ * Creates a quaternion that rotates from the -Y axis to the given direction.
+ *
+ * <p>The arrow by default points in the -Y direction. This method computes
+ * the rotation needed to align the arrow with the target direction vector.</p>
+ *
+ * @param nx normalized direction X component
+ * @param ny normalized direction Y component
+ * @param nz normalized direction Z component
+ * @return quaternion representing the rotation
+ */
+ private Quaternion createRotationFromYAxis(final double nx, final double ny, final double nz) {
+ // Default direction is -Y (0, -1, 0)
+ // Target direction is (nx, ny, nz)
+ // Dot product: 0*nx + (-1)*ny + 0*nz = -ny
+ final double dot = -ny;
+
+ // Check for parallel vectors
+ if (dot > 0.9999) {
+ // Direction is nearly -Y, no rotation needed
+ return Quaternion.identity();
+ }
+ if (dot < -0.9999) {
+ // Direction is nearly +Y, rotate 180° around X axis
+ return Quaternion.fromAxisAngle(new Point3D(1, 0, 0), Math.PI);
+ }
+
+ // Cross product: (0, -1, 0) x (nx, ny, nz) = (-nz, 0, nx)
+ // This gives the rotation axis
+ final double axisX = -nz;
+ final double axisY = 0;
+ final double axisZ = nx;
+ final double axisLength = Math.sqrt(axisX * axisX + axisY * axisY + axisZ * axisZ);
+ final double normalizedAxisX = axisX / axisLength;
+ final double normalizedAxisZ = axisZ / axisLength;
+
+ // Angle from dot product
+ final double angle = Math.acos(dot);
+
+ return Quaternion.fromAxisAngle(
+ new Point3D(normalizedAxisX, 0, normalizedAxisZ), angle);
+ }
+
+ /**
+ * Adds the cylindrical body of the arrow.
+ *
+ * <p>The cylinder is created with its base at the start point and extends
+ * in the direction of the arrow for the specified body length.</p>
+ *
+ * <p><b>Local coordinate system:</b> The arrow points in -Y direction in local space.
+ * Therefore, local -Y is toward the tip (front), and local +Y is toward the start (back).</p>
+ *
+ * @param startPoint the origin of the arrow body
+ * @param radius the radius of the cylinder
+ * @param length the length of the cylinder
+ * @param segments the number of segments around the circumference
+ * @param color the fill color
+ * @param rotMatrix the rotation matrix to apply
+ * @param dirX direction X component (for translation calculation)
+ * @param dirY direction Y component
+ * @param dirZ direction Z component
+ */
+ private void addCylinderBody(final Point3D startPoint, final double radius,
+ final double length, final int segments,
+ final Color color, final Matrix3x3 rotMatrix,
+ final double dirX, final double dirY, final double dirZ) {
+ // Cylinder center is at startPoint + (length/2) * direction
+ final double centerX = startPoint.x + (length / 2.0) * dirX;
+ final double centerY = startPoint.y + (length / 2.0) * dirY;
+ final double centerZ = startPoint.z + (length / 2.0) * dirZ;
+
+ // Generate ring vertices in local space, then rotate and translate
+ // Arrow points in -Y direction, so:
+ // - tipSideRing is at local -Y (toward arrow tip, front of cylinder)
+ // - startSideRing is at local +Y (toward arrow start, back of cylinder)
+ final Point3D[] tipSideRing = new Point3D[segments];
+ final Point3D[] startSideRing = new Point3D[segments];
+
+ final double halfLength = length / 2.0;
+
+ for (int i = 0; i < segments; i++) {
+ final double angle = 2.0 * Math.PI * i / segments;
+ final double localX = radius * Math.cos(angle);
+ final double localZ = radius * Math.sin(angle);
+
+ // Tip-side ring (at -halfLength in local Y = toward arrow tip)
+ final Point3D tipSideLocal = new Point3D(localX, -halfLength, localZ);
+ rotMatrix.transform(tipSideLocal, tipSideLocal);
+ tipSideLocal.x += centerX;
+ tipSideLocal.y += centerY;
+ tipSideLocal.z += centerZ;
+ tipSideRing[i] = tipSideLocal;
+
+ // Start-side ring (at +halfLength in local Y = toward arrow start)
+ final Point3D startSideLocal = new Point3D(localX, halfLength, localZ);
+ rotMatrix.transform(startSideLocal, startSideLocal);
+ startSideLocal.x += centerX;
+ startSideLocal.y += centerY;
+ startSideLocal.z += centerZ;
+ startSideRing[i] = startSideLocal;
+ }
+
+ // Create cylinder side faces (one quad per segment)
+ // Winding: tipSide[i] → startSide[i] → startSide[next] → tipSide[next]
+ // creates CCW winding when viewed from outside the cylinder
+ for (int i = 0; i < segments; i++) {
+ final int next = (i + 1) % segments;
+
+ addShape(SolidPolygon.quad(
+ tipSideRing[i],
+ startSideRing[i],
+ startSideRing[next],
+ tipSideRing[next],
+ color));
+ }
+
+ // Add back cap at the start point.
+ // Single N-vertex polygon that closes the loop to create segments triangles
+ // (segments+2 vertices → segments triangles via fan triangulation)
+ // The cap faces backward (away from arrow tip), opposite to arrow direction.
+ // Winding: center → ring[segments-1] → ... → ring[1] → ring[0] → ring[segments-1]
+ // (reverse order from ring array direction)
+ final Point3D[] backCapVertices = new Point3D[segments + 2];
+ backCapVertices[0] = startPoint;
+ for (int i = 0; i < segments; i++) {
+ backCapVertices[i + 1] = startSideRing[segments - 1 - i];
+ }
+ backCapVertices[segments + 1] = startSideRing[segments - 1]; // close the loop
+ addShape(new SolidPolygon(backCapVertices, color));
+ }
+
+ /**
+ * Adds the conical tip of the arrow.
+ *
+ * <p>The cone is created with its apex at the end point (the arrow tip)
+ * and its base pointing back towards the start point.</p>
+ *
+ * <p><b>Local coordinate system:</b> In local space, the cone points in -Y direction
+ * (apex at lower Y). The base ring is at Y=0, and the apex is at Y=-length.</p>
+ *
+ * @param endPoint the position of the arrow tip (cone apex)
+ * @param radius the radius of the cone base
+ * @param length the length of the cone
+ * @param segments the number of segments around the circumference
+ * @param color the fill color
+ * @param rotMatrix the rotation matrix to apply
+ * @param dirX direction X component
+ * @param dirY direction Y component
+ * @param dirZ direction Z component
+ */
+ private void addConeTip(final Point3D endPoint, final double radius,
+ final double length, final int segments,
+ final Color color, final Matrix3x3 rotMatrix,
+ final double dirX, final double dirY, final double dirZ) {
+ // Apex is at endPoint (the arrow tip)
+ // Base center is at endPoint - length * direction (toward arrow start)
+ final double baseCenterX = endPoint.x - length * dirX;
+ final double baseCenterY = endPoint.y - length * dirY;
+ final double baseCenterZ = endPoint.z - length * dirZ;
+
+ // Generate base ring vertices
+ // In local space, cone points in -Y direction, so base is at Y=0
+ final Point3D[] baseRing = new Point3D[segments];
+
+ for (int i = 0; i < segments; i++) {
+ final double angle = 2.0 * Math.PI * i / segments;
+ final double localX = radius * Math.cos(angle);
+ final double localZ = radius * Math.sin(angle);
+
+ // Base ring vertices at local Y=0
+ final Point3D local = new Point3D(localX, 0, localZ);
+ rotMatrix.transform(local, local);
+ local.x += baseCenterX;
+ local.y += baseCenterY;
+ local.z += baseCenterZ;
+ baseRing[i] = local;
+ }
+
+ // Apex point (the arrow tip)
+ final Point3D apex = new Point3D(endPoint.x, endPoint.y, endPoint.z);
+
+ // Create cone side faces
+ // Winding: apex → current → next creates CCW winding when viewed from outside
+ for (int i = 0; i < segments; i++) {
+ final int next = (i + 1) % segments;
+
+ addShape(new SolidPolygon(
+ new Point3D(apex.x, apex.y, apex.z),
+ new Point3D(baseRing[i].x, baseRing[i].y, baseRing[i].z),
+ new Point3D(baseRing[next].x, baseRing[next].y, baseRing[next].z),
+ color));
+ }
+
+ // Create base cap of the cone tip (fills the gap between cone and cylinder body)
+ // Single N-vertex polygon that closes the loop to create segments triangles
+ // (segments+2 vertices → segments triangles via fan triangulation)
+ // The base cap faces toward the arrow body/start, opposite to the cone's pointing direction.
+ // Winding: center → ring[segments-1] → ... → ring[1] → ring[0] → ring[segments-1]
+ final Point3D baseCenter = new Point3D(baseCenterX, baseCenterY, baseCenterZ);
+ final Point3D[] tipBaseCapVertices = new Point3D[segments + 2];
+ tipBaseCapVertices[0] = baseCenter;
+ for (int i = 0; i < segments; i++) {
+ tipBaseCapVertices[i + 1] = baseRing[segments - 1 - i];
+ }
+ tipBaseCapVertices[segments + 1] = baseRing[segments - 1]; // close the loop
+ addShape(new SolidPolygon(tipBaseCapVertices, color));
+ }
+}
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.solid;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.math.Matrix3x3;
+import eu.svjatoslav.aukio.e3d.math.Quaternion;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon.SolidPolygon;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape;
+
+/**
+ * A solid cone that can be oriented in any direction.
+ *
+ * <p>The cone has a circular base and a single apex (tip) point. Two constructors
+ * are provided for different use cases:</p>
+ *
+ * <ul>
+ * <li><b>Directional (recommended):</b> Specify apex point and base center point.
+ * The cone points from apex toward the base center. This allows arbitrary
+ * orientation and is the most intuitive API.</li>
+ * <li><b>Y-axis aligned:</b> Specify base center, radius, and height. The cone
+ * points in -Y direction (apex at lower Y). Useful for simple vertical cones.</li>
+ * </ul>
+ *
+ * <p><b>Usage examples:</b></p>
+ * <pre>{@code
+ * // Directional constructor: cone pointing from apex toward base
+ * SolidPolygonCone directionalCone = new SolidPolygonCone(
+ * new Point3D(0, -100, 0), // apex (tip of the cone)
+ * new Point3D(0, 50, 0), // baseCenter (cone points toward this)
+ * 50, // radius of the circular base
+ * 16, // segments
+ * Color.RED
+ * );
+ *
+ * // Y-axis aligned constructor: cone pointing upward
+ * SolidPolygonCone verticalCone = new SolidPolygonCone(
+ * new Point3D(0, 0, 300), // baseCenter
+ * 50, // radius
+ * 100, // height
+ * 16, // segments
+ * Color.RED
+ * );
+ * }</pre>
+ *
+ * @see SolidPolygonCylinder
+ * @see SolidPolygonArrow
+ * @see SolidPolygon
+ */
+public class SolidPolygonCone extends AbstractCompositeShape {
+
+ /**
+ * Constructs a solid cone pointing from apex toward base center.
+ *
+ * <p>This is the recommended constructor for placing cones in 3D space.
+ * The cone's apex (tip) is at {@code apexPoint}, and the circular base
+ * is centered at {@code baseCenterPoint}. The cone points in the direction
+ * from apex to base center.</p>
+ *
+ * <p><b>Coordinate interpretation:</b></p>
+ * <ul>
+ * <li>{@code apexPoint} - the sharp tip of the cone</li>
+ * <li>{@code baseCenterPoint} - the center of the circular base; the cone
+ * "points" in this direction from the apex</li>
+ * <li>The distance between apex and base center determines the cone height</li>
+ * </ul>
+ *
+ * @param apexPoint the position of the cone's tip (apex)
+ * @param baseCenterPoint the center point of the circular base; the cone
+ * points from apex toward this point
+ * @param radius the radius of the circular base
+ * @param segments the number of segments around the circumference.
+ * Higher values create smoother cones. Minimum is 3.
+ * @param color the fill color applied to all faces of the cone
+ */
+ public SolidPolygonCone(final Point3D apexPoint, final Point3D baseCenterPoint,
+ final double radius, final int segments,
+ final Color color) {
+ super();
+
+ // Calculate direction and height from apex to base center
+ final double dx = baseCenterPoint.x - apexPoint.x;
+ final double dy = baseCenterPoint.y - apexPoint.y;
+ final double dz = baseCenterPoint.z - apexPoint.z;
+ final double height = Math.sqrt(dx * dx + dy * dy + dz * dz);
+
+ // Handle degenerate case: apex and base center are the same point
+ if (height < 0.001) {
+ return;
+ }
+
+ // Normalize direction vector (from apex toward base)
+ final double nx = dx / height;
+ final double ny = dy / height;
+ final double nz = dz / height;
+
+ // Calculate rotation to align Y-axis with direction
+ // Default cone points in -Y direction (apex at origin, base at -Y)
+ // We need to rotate from (0, -1, 0) to (nx, ny, nz)
+ final Quaternion rotation = createRotationFromYAxis(nx, ny, nz);
+ final Matrix3x3 rotMatrix = rotation.toMatrix();
+
+ // Generate base ring vertices in local space, then rotate and translate
+ // In local space: apex is at origin, base is at Y = -height
+ // (cone points in -Y direction in local space)
+ final Point3D[] baseRing = new Point3D[segments];
+
+ for (int i = 0; i < segments; i++) {
+ final double angle = 2.0 * Math.PI * i / segments;
+ final double localX = radius * Math.cos(angle);
+ final double localZ = radius * Math.sin(angle);
+
+ // Base ring vertex in local space (Y = -height)
+ final Point3D local = new Point3D(localX, -height, localZ);
+ rotMatrix.transform(local, local);
+ local.x += apexPoint.x;
+ local.y += apexPoint.y;
+ local.z += apexPoint.z;
+ baseRing[i] = local;
+ }
+
+ // Apex point (the cone tip)
+ final Point3D apex = new Point3D(apexPoint.x, apexPoint.y, apexPoint.z);
+
+ // Create side faces connecting each pair of adjacent base vertices to the apex
+ // Winding: apex → next → current creates CCW winding when viewed from outside
+ // (Base ring vertices go CCW when viewed from apex looking at base, so we reverse)
+ for (int i = 0; i < segments; i++) {
+ final int next = (i + 1) % segments;
+
+ addShape(new SolidPolygon(
+ new Point3D(apex.x, apex.y, apex.z),
+ new Point3D(baseRing[next].x, baseRing[next].y, baseRing[next].z),
+ new Point3D(baseRing[i].x, baseRing[i].y, baseRing[i].z),
+ color));
+ }
+
+ // Create base cap (circular bottom face)
+ // Single N-vertex polygon that closes the loop to create segments triangles
+ // (segments+2 vertices → segments triangles via fan triangulation)
+ // The cap faces away from the apex (in the direction the cone points).
+ // Winding: center → ring[0] → ring[1] → ... → ring[segments-1] → ring[0]
+ final Point3D[] baseCapVertices = new Point3D[segments + 2];
+ baseCapVertices[0] = baseCenterPoint;
+ for (int i = 0; i < segments; i++) {
+ baseCapVertices[i + 1] = baseRing[i];
+ }
+ baseCapVertices[segments + 1] = baseRing[0]; // close the loop
+ addShape(new SolidPolygon(baseCapVertices, color));
+
+ setBackfaceCulling(true);
+ }
+
+ /**
+ * Constructs a solid cone with circular base centered at the given point,
+ * pointing in the -Y direction.
+ *
+ * <p>This constructor creates a Y-axis aligned cone. The apex is positioned
+ * at {@code baseCenter.y - height} (above the base in the negative Y direction).
+ * For cones pointing in arbitrary directions, use
+ * {@link #SolidPolygonCone(Point3D, Point3D, double, int, Color)} instead.</p>
+ *
+ * <p><b>Coordinate system:</b> The cone points in -Y direction (apex at lower Y).
+ * The base is at Y=baseCenter.y, and the apex is at Y=baseCenter.y - height.
+ * In Aukio 3D's coordinate system, "up" visually is negative Y.</p>
+ *
+ * @param baseCenter the center point of the cone's circular base in 3D space
+ * @param radius the radius of the circular base
+ * @param height the height of the cone from base center to apex
+ * @param segments the number of segments around the circumference.
+ * Higher values create smoother cones. Minimum is 3.
+ * @param color the fill color applied to all faces of the cone
+ */
+ public SolidPolygonCone(final Point3D baseCenter, final double radius,
+ final double height, final int segments,
+ final Color color) {
+ super();
+
+ // Apex is above the base (negative Y direction in this coordinate system)
+ final double apexY = baseCenter.y - height;
+ final Point3D apex = new Point3D(baseCenter.x, apexY, baseCenter.z);
+
+ // Generate vertices around the circular base
+ // Vertices are ordered counter-clockwise when viewed from above (from +Y)
+ final Point3D[] baseRing = new Point3D[segments];
+ for (int i = 0; i < segments; i++) {
+ final double angle = 2.0 * Math.PI * i / segments;
+ final double x = baseCenter.x + radius * Math.cos(angle);
+ final double z = baseCenter.z + radius * Math.sin(angle);
+ baseRing[i] = new Point3D(x, baseCenter.y, z);
+ }
+
+ // Create side faces connecting each pair of adjacent base vertices to the apex
+ // Winding: apex → next → current creates CCW winding when viewed from outside
+ // (Base ring vertices go CCW when viewed from apex looking at base, so we reverse)
+ for (int i = 0; i < segments; i++) {
+ final int next = (i + 1) % segments;
+
+ addShape(new SolidPolygon(
+ new Point3D(apex.x, apex.y, apex.z),
+ new Point3D(baseRing[next].x, baseRing[next].y, baseRing[next].z),
+ new Point3D(baseRing[i].x, baseRing[i].y, baseRing[i].z),
+ color));
+ }
+
+ // Create base cap (circular bottom face)
+ // Single N-vertex polygon that closes the loop to create segments triangles
+ // (segments+2 vertices → segments triangles via fan triangulation)
+ // The base cap faces in +Y direction (downward, away from apex).
+ // Winding: center → ring[0] → ring[1] → ... → ring[segments-1] → ring[0]
+ final Point3D[] baseCapVertices = new Point3D[segments + 2];
+ baseCapVertices[0] = baseCenter;
+ for (int i = 0; i < segments; i++) {
+ baseCapVertices[i + 1] = baseRing[i];
+ }
+ baseCapVertices[segments + 1] = baseRing[0]; // close the loop
+ addShape(new SolidPolygon(baseCapVertices, color));
+
+ setBackfaceCulling(true);
+ }
+
+ /**
+ * Creates a quaternion that rotates from the -Y axis to the given direction.
+ *
+ * <p>The cone by default points in the -Y direction (apex at origin, base at -Y).
+ * This method computes the rotation needed to align the cone with the target
+ * direction vector.</p>
+ *
+ * @param nx normalized direction X component
+ * @param ny normalized direction Y component
+ * @param nz normalized direction Z component
+ * @return quaternion representing the rotation
+ */
+ private Quaternion createRotationFromYAxis(final double nx, final double ny, final double nz) {
+ // Default direction is -Y (0, -1, 0)
+ // Target direction is (nx, ny, nz)
+ // Dot product: 0*nx + (-1)*ny + 0*nz = -ny
+ final double dot = -ny;
+
+ // Check for parallel vectors
+ if (dot > 0.9999) {
+ // Direction is nearly -Y, no rotation needed
+ return Quaternion.identity();
+ }
+ if (dot < -0.9999) {
+ // Direction is nearly +Y, rotate 180° around X axis
+ return Quaternion.fromAxisAngle(new Point3D(1, 0, 0), Math.PI);
+ }
+
+ // Cross product: (0, -1, 0) x (nx, ny, nz) = (-nz, 0, nx)
+ // This gives the rotation axis
+ final double axisX = -nz;
+ final double axisY = 0;
+ final double axisZ = nx;
+ final double axisLength = Math.sqrt(axisX * axisX + axisY * axisY + axisZ * axisZ);
+ final double normalizedAxisX = axisX / axisLength;
+ final double normalizedAxisZ = axisZ / axisLength;
+
+ // Angle from dot product
+ final double angle = Math.acos(dot);
+
+ return Quaternion.fromAxisAngle(
+ new Point3D(normalizedAxisX, 0, normalizedAxisZ), angle);
+ }
+}
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.solid;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+
+/**
+ * A solid cube centered at a given point with equal side length along all axes.
+ * This is a convenience subclass of {@link SolidPolygonRectangularBox} that
+ * constructs a cube from a center point and a half-side length.
+ *
+ * <p>The cube extends {@code size} units in each direction from the center,
+ * resulting in a total edge length of {@code 2 * size}.</p>
+ *
+ * <p><b>Usage example:</b></p>
+ * <pre>{@code
+ * SolidPolygonCube cube = new SolidPolygonCube(
+ * new Point3D(0, 0, 300), 50, Color.GREEN);
+ * shapeCollection.addShape(cube);
+ * }</pre>
+ *
+ * @see SolidPolygonRectangularBox
+ * @see Color
+ */
+public class SolidPolygonCube extends SolidPolygonRectangularBox {
+
+ /**
+ * Constructs a solid cube centered at the given point.
+ *
+ * @param center the center point of the cube in 3D space
+ * @param size the half-side length; the cube extends this distance from
+ * the center along each axis, giving a total edge length of
+ * {@code 2 * size}
+ * @param color the fill color applied to all faces of the cube
+ */
+ public SolidPolygonCube(final Point3D center, final double size,
+ final Color color) {
+ super(new Point3D(center.x - size, center.y - size, center.z - size),
+ new Point3D(center.x + size, center.y + size, center.z + size),
+ color);
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.solid;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.math.Matrix3x3;
+import eu.svjatoslav.aukio.e3d.math.Quaternion;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon.SolidPolygon;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape;
+
+/**
+ * A solid cylinder defined by two end points.
+ *
+ * <p>The cylinder extends from startPoint to endPoint with circular caps at both
+ * ends. The number of segments determines the smoothness of the curved surface.</p>
+ *
+ * <p><b>Usage example:</b></p>
+ * <pre>{@code
+ * // Create a vertical cylinder from Y=100 to Y=200
+ * SolidPolygonCylinder cylinder = new SolidPolygonCylinder(
+ * new Point3D(0, 100, 0), // start point (bottom)
+ * new Point3D(0, 200, 0), // end point (top)
+ * 10, // radius
+ * 16, // segments
+ * Color.RED // color
+ * );
+ *
+ * // Create a horizontal cylinder along X axis
+ * SolidPolygonCylinder pipe = new SolidPolygonCylinder(
+ * new Point3D(-50, 0, 0),
+ * new Point3D(50, 0, 0),
+ * 5, 12, Color.BLUE
+ * );
+ * }</pre>
+ *
+ * @see SolidPolygonCone
+ * @see SolidPolygonArrow
+ * @see SolidPolygon
+ */
+public class SolidPolygonCylinder extends AbstractCompositeShape {
+
+ /**
+ * Constructs a solid cylinder between two end points.
+ *
+ * <p>The cylinder has circular caps at both startPoint and endPoint,
+ * connected by a curved side surface. The orientation is automatically
+ * calculated from the direction between the two points.</p>
+ *
+ * @param startPoint the center of the first cap
+ * @param endPoint the center of the second cap
+ * @param radius the radius of the cylinder
+ * @param segments the number of segments around the circumference.
+ * Higher values create smoother cylinders. Minimum is 3.
+ * @param color the fill color applied to all polygons
+ */
+ public SolidPolygonCylinder(final Point3D startPoint, final Point3D endPoint,
+ final double radius, final int segments,
+ final Color color) {
+ super();
+
+ // Calculate direction and distance
+ final double dx = endPoint.x - startPoint.x;
+ final double dy = endPoint.y - startPoint.y;
+ final double dz = endPoint.z - startPoint.z;
+ final double distance = Math.sqrt(dx * dx + dy * dy + dz * dz);
+
+ // Handle degenerate case: start and end are the same point
+ if (distance < 0.001) {
+ return;
+ }
+
+ // Normalize direction vector
+ final double nx = dx / distance;
+ final double ny = dy / distance;
+ final double nz = dz / distance;
+
+ // Calculate rotation to align Y-axis with direction
+ // Default cylinder is aligned along Y-axis
+ // We need to rotate from (0, 1, 0) to (nx, ny, nz)
+ final Quaternion rotation = createRotationFromYAxis(nx, ny, nz);
+ final Matrix3x3 rotMatrix = rotation.toMatrix();
+
+ // Cylinder center is at midpoint between start and end
+ final double centerX = (startPoint.x + endPoint.x) / 2.0;
+ final double centerY = (startPoint.y + endPoint.y) / 2.0;
+ final double centerZ = (startPoint.z + endPoint.z) / 2.0;
+ final double halfLength = distance / 2.0;
+
+ // Generate ring vertices in local space, then rotate and translate
+ // In local space: cylinder is aligned along Y-axis
+ // - startSideRing is at local -Y (toward startPoint)
+ // - endSideRing is at local +Y (toward endPoint)
+ final Point3D[] startSideRing = new Point3D[segments];
+ final Point3D[] endSideRing = new Point3D[segments];
+
+ for (int i = 0; i < segments; i++) {
+ final double angle = 2.0 * Math.PI * i / segments;
+ final double localX = radius * Math.cos(angle);
+ final double localZ = radius * Math.sin(angle);
+
+ // Start-side ring (at -halfLength in local Y = toward startPoint)
+ final Point3D startLocal = new Point3D(localX, -halfLength, localZ);
+ rotMatrix.transform(startLocal, startLocal);
+ startLocal.x += centerX;
+ startLocal.y += centerY;
+ startLocal.z += centerZ;
+ startSideRing[i] = startLocal;
+
+ // End-side ring (at +halfLength in local Y = toward endPoint)
+ final Point3D endLocal = new Point3D(localX, halfLength, localZ);
+ rotMatrix.transform(endLocal, endLocal);
+ endLocal.x += centerX;
+ endLocal.y += centerY;
+ endLocal.z += centerZ;
+ endSideRing[i] = endLocal;
+ }
+
+ // Create side faces (one quad per segment)
+ // Winding: startSide[i] → endSide[i] → endSide[next] → startSide[next]
+ // creates CCW winding when viewed from outside the cylinder
+ for (int i = 0; i < segments; i++) {
+ final int next = (i + 1) % segments;
+
+ addShape(SolidPolygon.quad(
+ startSideRing[i],
+ endSideRing[i],
+ endSideRing[next],
+ startSideRing[next],
+ color));
+ }
+
+ // Create start cap (at startPoint, faces outward from cylinder)
+ // Single N-vertex polygon that closes the loop to create segments triangles
+ // (segments+2 vertices → segments triangles via fan triangulation)
+ // Winding: center → ring[0] → ring[1] → ... → ring[segments-1] → ring[0]
+ final Point3D[] startCapVertices = new Point3D[segments + 2];
+ startCapVertices[0] = startPoint;
+ for (int i = 0; i < segments; i++) {
+ startCapVertices[i + 1] = startSideRing[i];
+ }
+ startCapVertices[segments + 1] = startSideRing[0]; // close the loop
+ addShape(new SolidPolygon(startCapVertices, color));
+
+ // Create end cap (at endPoint, faces outward from cylinder)
+ // Reverse winding for opposite-facing cap
+ // Winding: center → ring[segments-1] → ... → ring[1] → ring[0] → ring[segments-1]
+ final Point3D[] endCapVertices = new Point3D[segments + 2];
+ endCapVertices[0] = endPoint;
+ for (int i = 0; i < segments; i++) {
+ endCapVertices[i + 1] = endSideRing[segments - 1 - i];
+ }
+ endCapVertices[segments + 1] = endSideRing[segments - 1]; // close the loop
+ addShape(new SolidPolygon(endCapVertices, color));
+
+ setBackfaceCulling(true);
+ }
+
+ /**
+ * Creates a quaternion that rotates from the +Y axis to the given direction.
+ *
+ * @param nx normalized direction X component
+ * @param ny normalized direction Y component
+ * @param nz normalized direction Z component
+ * @return quaternion representing the rotation
+ */
+ private Quaternion createRotationFromYAxis(final double nx, final double ny, final double nz) {
+ // Default direction is +Y (0, 1, 0)
+ // Target direction is (nx, ny, nz)
+ // Dot product: 0*nx + 1*ny + 0*nz = ny
+ final double dot = ny;
+
+ // Check for parallel vectors
+ if (dot > 0.9999) {
+ // Direction is nearly +Y, no rotation needed
+ return Quaternion.identity();
+ }
+ if (dot < -0.9999) {
+ // Direction is nearly -Y, rotate 180° around X axis
+ return Quaternion.fromAxisAngle(new Point3D(1, 0, 0), Math.PI);
+ }
+
+ // Cross product: (0, 1, 0) x (nx, ny, nz) = (nz, 0, -nx)
+ // This gives the rotation axis
+ final double axisX = nz;
+ final double axisY = 0;
+ final double axisZ = -nx;
+ final double axisLength = Math.sqrt(axisX * axisX + axisY * axisY + axisZ * axisZ);
+ final double normalizedAxisX = axisX / axisLength;
+ final double normalizedAxisZ = axisZ / axisLength;
+
+ // Angle from dot product
+ final double angle = Math.acos(dot);
+
+ return Quaternion.fromAxisAngle(
+ new Point3D(normalizedAxisX, 0, normalizedAxisZ), angle);
+ }
+}
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.solid;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.math.Matrix3x3;
+import eu.svjatoslav.aukio.e3d.math.Quaternion;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon.SolidPolygon;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape;
+
+/**
+ * A solid square-based pyramid that can be oriented in any direction.
+ *
+ * <p>The pyramid has a square base and four triangular faces meeting at an apex
+ * (tip). Two constructors are provided for different use cases:</p>
+ *
+ * <ul>
+ * <li><b>Directional (recommended):</b> Specify apex point and base center point.
+ * The pyramid points from apex toward the base center. This allows arbitrary
+ * orientation and is the most intuitive API.</li>
+ * <li><b>Y-axis aligned:</b> Specify base center, base size, and height. The pyramid
+ * points in -Y direction (apex at lower Y). Useful for simple vertical pyramids.</li>
+ * </ul>
+ *
+ * <p><b>Usage examples:</b></p>
+ * <pre>{@code
+ * // Directional constructor: pyramid pointing from apex toward base
+ * SolidPolygonPyramid directionalPyramid = new SolidPolygonPyramid(
+ * new Point3D(0, -100, 0), // apex (tip of the pyramid)
+ * new Point3D(0, 50, 0), // baseCenter (pyramid points toward this)
+ * 50, // baseSize (half-width of square base)
+ * Color.RED
+ * );
+ *
+ * // Y-axis aligned constructor: pyramid pointing upward
+ * SolidPolygonPyramid verticalPyramid = new SolidPolygonPyramid(
+ * new Point3D(0, 0, 300), // baseCenter
+ * 50, // baseSize (half-width of square base)
+ * 100, // height
+ * Color.BLUE
+ * );
+ * }</pre>
+ *
+ * @see SolidPolygonCone
+ * @see SolidPolygonCube
+ * @see SolidPolygon
+ */
+public class SolidPolygonPyramid extends AbstractCompositeShape {
+
+ /**
+ * Constructs a solid square-based pyramid pointing from apex toward base center.
+ *
+ * <p>This is the recommended constructor for placing pyramids in 3D space.
+ * The pyramid's apex (tip) is at {@code apexPoint}, and the square base
+ * is centered at {@code baseCenter}. The pyramid points in the direction
+ * from apex to base center.</p>
+ *
+ * <p><b>Coordinate interpretation:</b></p>
+ * <ul>
+ * <li>{@code apexPoint} - the sharp tip of the pyramid</li>
+ * <li>{@code baseCenter} - the center of the square base; the pyramid
+ * "points" in this direction from the apex</li>
+ * <li>{@code baseSize} - half the width of the square base; the base
+ * extends this distance from the center along perpendicular axes</li>
+ * <li>The distance between apex and base center determines the pyramid height</li>
+ * </ul>
+ *
+ * @param apexPoint the position of the pyramid's tip (apex)
+ * @param baseCenter the center point of the square base; the pyramid
+ * points from apex toward this point
+ * @param baseSize the half-width of the square base; the base extends
+ * this distance from the center, giving a total base
+ * edge length of {@code 2 * baseSize}
+ * @param color the fill color applied to all faces of the pyramid
+ */
+ public SolidPolygonPyramid(final Point3D apexPoint, final Point3D baseCenter,
+ final double baseSize, final Color color) {
+ super();
+
+ // Calculate direction and height from apex to base center
+ final double dx = baseCenter.x - apexPoint.x;
+ final double dy = baseCenter.y - apexPoint.y;
+ final double dz = baseCenter.z - apexPoint.z;
+ final double height = Math.sqrt(dx * dx + dy * dy + dz * dz);
+
+ // Handle degenerate case: apex and base center are the same point
+ if (height < 0.001) {
+ return;
+ }
+
+ // Normalize direction vector (from apex toward base)
+ final double nx = dx / height;
+ final double ny = dy / height;
+ final double nz = dz / height;
+
+ // Calculate rotation to align Y-axis with direction
+ // Default pyramid points in -Y direction (apex at origin, base at -Y)
+ // We need to rotate from (0, -1, 0) to (nx, ny, nz)
+ final Quaternion rotation = createRotationFromYAxis(nx, ny, nz);
+ final Matrix3x3 rotMatrix = rotation.toMatrix();
+
+ // Generate base corner vertices in local space, then rotate and translate
+ // In local space: apex is at origin, base is at Y = -height
+ // Base corners form a square centered at (0, -height, 0)
+ final double h = baseSize;
+ final Point3D[] baseCorners = new Point3D[4];
+
+ // Local space corner positions (before rotation)
+ // Arranged clockwise when viewed from apex (from +Y)
+ final double[][] localCorners = {
+ {-h, -height, -h}, // corner 0: negative X, negative Z
+ {+h, -height, -h}, // corner 1: positive X, negative Z
+ {+h, -height, +h}, // corner 2: positive X, positive Z
+ {-h, -height, +h} // corner 3: negative X, positive Z
+ };
+
+ for (int i = 0; i < 4; i++) {
+ final Point3D local = new Point3D(localCorners[i][0], localCorners[i][1], localCorners[i][2]);
+ rotMatrix.transform(local, local);
+ local.x += apexPoint.x;
+ local.y += apexPoint.y;
+ local.z += apexPoint.z;
+ baseCorners[i] = local;
+ }
+
+ // Apex point (the pyramid tip)
+ final Point3D apex = new Point3D(apexPoint.x, apexPoint.y, apexPoint.z);
+
+ // Create the four triangular faces connecting apex to base edges
+ // Winding: next → current → apex creates CCW winding when viewed from outside
+ // (Base corners go CW when viewed from apex, so we reverse to get outward normals)
+ for (int i = 0; i < 4; i++) {
+ final int next = (i + 1) % 4;
+ addShape(new SolidPolygon(
+ new Point3D(baseCorners[next].x, baseCorners[next].y, baseCorners[next].z),
+ new Point3D(baseCorners[i].x, baseCorners[i].y, baseCorners[i].z),
+ new Point3D(apex.x, apex.y, apex.z),
+ color));
+ }
+
+ // Create base cap (square bottom face with center)
+ // Single N-vertex polygon that closes the loop to create 4 triangles
+ // (6 vertices → 4 triangles via fan triangulation)
+ // The cap faces away from the apex (in the direction the pyramid points).
+ // Winding: center → corner[3] → corner[0] → corner[1] → corner[2] → corner[3]
+ // (CW when viewed from apex, CCW when viewed from base side)
+ final Point3D[] baseCapVertices = new Point3D[6];
+ baseCapVertices[0] = baseCenter;
+ baseCapVertices[1] = baseCorners[3];
+ baseCapVertices[2] = baseCorners[0];
+ baseCapVertices[3] = baseCorners[1];
+ baseCapVertices[4] = baseCorners[2];
+ baseCapVertices[5] = baseCorners[3]; // close the loop
+ addShape(new SolidPolygon(baseCapVertices, color));
+
+ setBackfaceCulling(true);
+ }
+
+ /**
+ * Constructs a solid square-based pyramid with base centered at the given point,
+ * pointing in the -Y direction.
+ *
+ * <p>This constructor creates a Y-axis aligned pyramid. The apex is positioned
+ * at {@code baseCenter.y - height} (above the base in the negative Y direction).
+ * For pyramids pointing in arbitrary directions, use
+ * {@link #SolidPolygonPyramid(Point3D, Point3D, double, Color)} instead.</p>
+ *
+ * <p><b>Coordinate system:</b> The pyramid points in -Y direction (apex at lower Y).
+ * The base is at Y=baseCenter.y, and the apex is at Y=baseCenter.y - height.
+ * In Aukio 3D's coordinate system, "up" visually is negative Y.</p>
+ *
+ * @param baseCenter the center point of the pyramid's base in 3D space
+ * @param baseSize the half-width of the square base; the base extends
+ * this distance from the center along X and Z axes,
+ * giving a total base edge length of {@code 2 * baseSize}
+ * @param height the height of the pyramid from base center to apex
+ * @param color the fill color applied to all faces of the pyramid
+ */
+ public SolidPolygonPyramid(final Point3D baseCenter, final double baseSize,
+ final double height, final Color color) {
+ super();
+
+ final double halfBase = baseSize;
+ final double apexY = baseCenter.y - height;
+ final double baseY = baseCenter.y;
+
+ // Base corners arranged clockwise when viewed from above (+Y)
+ // Naming: "negative/positive X" and "negative/positive Z" relative to base center
+ final Point3D negXnegZ = new Point3D(baseCenter.x - halfBase, baseY, baseCenter.z - halfBase);
+ final Point3D posXnegZ = new Point3D(baseCenter.x + halfBase, baseY, baseCenter.z - halfBase);
+ final Point3D posXposZ = new Point3D(baseCenter.x + halfBase, baseY, baseCenter.z + halfBase);
+ final Point3D negXposZ = new Point3D(baseCenter.x - halfBase, baseY, baseCenter.z + halfBase);
+ final Point3D apex = new Point3D(baseCenter.x, apexY, baseCenter.z);
+
+ // Four triangular faces from apex to base edges
+ // Winding: apex → current → next creates CCW when viewed from outside
+ addShape(new SolidPolygon(negXnegZ, posXnegZ, apex, color));
+ addShape(new SolidPolygon(posXnegZ, posXposZ, apex, color));
+ addShape(new SolidPolygon(posXposZ, negXposZ, apex, color));
+ addShape(new SolidPolygon(negXposZ, negXnegZ, apex, color));
+
+ // Base cap (square bottom face)
+ // Single quad using the 4 corner vertices
+ // Cap faces +Y (downward, away from apex). The base is at higher Y than apex.
+ // For outward normal (+Y direction), we need CCW ordering when viewed from +Y.
+ // Quad order: negXposZ → posXposZ → posXnegZ → negXnegZ (CCW from +Y)
+ addShape(SolidPolygon.quad(negXposZ, posXposZ, posXnegZ, negXnegZ, color));
+
+ setBackfaceCulling(true);
+ }
+
+ /**
+ * Creates a quaternion that rotates from the -Y axis to the given direction.
+ *
+ * <p>The pyramid by default points in the -Y direction (apex at origin, base at -Y).
+ * This method computes the rotation needed to align the pyramid with the target
+ * direction vector.</p>
+ *
+ * @param nx normalized direction X component
+ * @param ny normalized direction Y component
+ * @param nz normalized direction Z component
+ * @return quaternion representing the rotation
+ */
+ private Quaternion createRotationFromYAxis(final double nx, final double ny, final double nz) {
+ // Default direction is -Y (0, -1, 0)
+ // Target direction is (nx, ny, nz)
+ // Dot product: 0*nx + (-1)*ny + 0*nz = -ny
+ final double dot = -ny;
+
+ // Check for parallel vectors
+ if (dot > 0.9999) {
+ // Direction is nearly -Y, no rotation needed
+ return Quaternion.identity();
+ }
+ if (dot < -0.9999) {
+ // Direction is nearly +Y, rotate 180° around X axis
+ return Quaternion.fromAxisAngle(new Point3D(1, 0, 0), Math.PI);
+ }
+
+ // Cross product: (0, -1, 0) x (nx, ny, nz) = (-nz, 0, nx)
+ // This gives the rotation axis
+ final double axisX = -nz;
+ final double axisY = 0;
+ final double axisZ = nx;
+ final double axisLength = Math.sqrt(axisX * axisX + axisY * axisY + axisZ * axisZ);
+ final double normalizedAxisX = axisX / axisLength;
+ final double normalizedAxisZ = axisZ / axisLength;
+
+ // Angle from dot product
+ final double angle = Math.acos(dot);
+
+ return Quaternion.fromAxisAngle(
+ new Point3D(normalizedAxisX, 0, normalizedAxisZ), angle);
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.solid;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon.SolidPolygon;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape;
+
+/**
+ * A solid (filled) rectangular box composed of 6 quadrilateral polygons (1 per face,
+ * covering all 6 faces).
+ *
+ * <p>The box is defined by two diagonally opposite corner points in 3D space.
+ * The box is axis-aligned, meaning its edges are parallel to the X, Y, and Z axes.</p>
+ *
+ * <p><b>Vertex layout:</b></p>
+ * <pre>
+ * cornerB (max) ────────┐
+ * /│ /│
+ * / │ / │
+ * / │ / │
+ * ┌───┼───────────┐ │
+ * │ │ │ │
+ * │ │ │ │
+ * │ └───────────│───┘
+ * │ / │ /
+ * │ / │ /
+ * │/ │/
+ * └───────────────┘ cornerA (min)
+ * </pre>
+ *
+ * <p>The eight vertices are derived from the two corner points:</p>
+ * <ul>
+ * <li>Corner A defines minimum X, Y, Z</li>
+ * <li>Corner B defines maximum X, Y, Z</li>
+ * <li>The other 6 vertices are computed from combinations of these coordinates</li>
+ * </ul>
+ *
+ * <p><b>Usage examples:</b></p>
+ * <pre>{@code
+ * // Create a box from two opposite corners
+ * SolidPolygonRectangularBox box = new SolidPolygonRectangularBox(
+ * new Point3D(-50, -25, 100), // cornerA (minimum X, Y, Z)
+ * new Point3D(50, 25, 200), // cornerB (maximum X, Y, Z)
+ * Color.BLUE
+ * );
+ *
+ * // Create a cube using center + size (see SolidPolygonCube for convenience)
+ * double size = 50;
+ * SolidPolygonRectangularBox cube = new SolidPolygonRectangularBox(
+ * new Point3D(0 - size, 0 - size, 200 - size), // cornerA
+ * new Point3D(0 + size, 0 + size, 200 + size), // cornerB
+ * Color.RED
+ * );
+ * }</pre>
+ *
+ * @see SolidPolygonCube
+ * @see SolidPolygon
+ */
+public class SolidPolygonRectangularBox extends AbstractCompositeShape {
+
+ /**
+ * Constructs a solid rectangular box between two diagonally opposite corner
+ * points in 3D space.
+ *
+ * <p>The box is axis-aligned and fills the rectangular region between the
+ * two corners. The corner points do not need to be ordered (cornerA can have
+ * larger coordinates than cornerB); the constructor will determine the actual
+ * min/max bounds automatically.</p>
+ *
+ * @param cornerA the first corner point (any of the 8 corners)
+ * @param cornerB the diagonally opposite corner point
+ * @param color the fill color applied to all 6 quadrilateral polygons
+ */
+ public SolidPolygonRectangularBox(final Point3D cornerA, final Point3D cornerB, final Color color) {
+ super();
+
+ // Determine actual min/max bounds (corners may be in any order)
+ final double minX = Math.min(cornerA.x, cornerB.x);
+ final double maxX = Math.max(cornerA.x, cornerB.x);
+ final double minY = Math.min(cornerA.y, cornerB.y);
+ final double maxY = Math.max(cornerA.y, cornerB.y);
+ final double minZ = Math.min(cornerA.z, cornerB.z);
+ final double maxZ = Math.max(cornerA.z, cornerB.z);
+
+ // Compute all 8 vertices from the bounds
+ // Naming convention: min/max indicates which bound the coordinate uses
+ // minMinMin = (minX, minY, minZ), maxMaxMax = (maxX, maxY, maxZ), etc.
+ final Point3D minMinMin = new Point3D(minX, minY, minZ);
+ final Point3D maxMinMin = new Point3D(maxX, minY, minZ);
+ final Point3D maxMinMax = new Point3D(maxX, minY, maxZ);
+ final Point3D minMinMax = new Point3D(minX, minY, maxZ);
+
+ final Point3D minMaxMin = new Point3D(minX, maxY, minZ);
+ final Point3D maxMaxMin = new Point3D(maxX, maxY, minZ);
+ final Point3D minMaxMax = new Point3D(minX, maxY, maxZ);
+ final Point3D maxMaxMax = new Point3D(maxX, maxY, maxZ);
+
+ // Bottom face (y = minY) - CCW when viewed from below
+ addShape(new SolidPolygon(new Point3D[]{minMinMin, maxMinMin, maxMinMax, minMinMax}, color));
+
+ // Top face (y = maxY) - CCW when viewed from above
+ addShape(new SolidPolygon(new Point3D[]{minMaxMin, minMaxMax, maxMaxMax, maxMaxMin}, color));
+
+ // Front face (z = minZ) - CCW when viewed from front
+ addShape(new SolidPolygon(new Point3D[]{minMinMin, minMaxMin, maxMaxMin, maxMinMin}, color));
+
+ // Back face (z = maxZ) - CCW when viewed from behind
+ addShape(new SolidPolygon(new Point3D[]{maxMinMax, maxMaxMax, minMaxMax, minMinMax}, color));
+
+ // Left face (x = minX) - CCW when viewed from left
+ addShape(new SolidPolygon(new Point3D[]{minMinMin, minMinMax, minMaxMax, minMaxMin}, color));
+
+ // Right face (x = maxX) - CCW when viewed from right
+ addShape(new SolidPolygon(new Point3D[]{maxMinMin, maxMaxMin, maxMaxMax, maxMinMax}, color));
+
+ setBackfaceCulling(true);
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.solid;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon.SolidPolygon;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape;
+
+/**
+ * A solid sphere composed of triangular polygons.
+ *
+ * <p>The sphere is constructed using a latitude-longitude grid (UV sphere).
+ * The number of segments determines the smoothness - more segments create
+ * a smoother sphere but require more polygons.</p>
+ *
+ * <p><b>Usage example:</b></p>
+ * <pre>{@code
+ * // Create a sphere with radius 50 and 16 segments (smooth)
+ * SolidPolygonSphere sphere = new SolidPolygonSphere(
+ * new Point3D(0, 0, 200), 50, 16, Color.RED);
+ * shapeCollection.addShape(sphere);
+ * }</pre>
+ *
+ * @see SolidPolygonCube
+ * @see SolidPolygon
+ * @see AbstractCompositeShape
+ */
+public class SolidPolygonSphere extends AbstractCompositeShape {
+
+ /**
+ * Constructs a solid sphere centered at the given point.
+ *
+ * @param center the center point of the sphere in 3D space
+ * @param radius the radius of the sphere
+ * @param segments the number of segments (latitude/longitude divisions).
+ * Higher values create smoother spheres. Minimum is 3.
+ * @param color the fill color applied to all triangular polygons
+ */
+ public SolidPolygonSphere(final Point3D center, final double radius,
+ final int segments, final Color color) {
+ super();
+
+ final int rings = segments;
+ final int sectors = segments * 2;
+
+ for (int i = 0; i < rings; i++) {
+ double lat0 = Math.PI * (-0.5 + (double) i / rings);
+ double lat1 = Math.PI * (-0.5 + (double) (i + 1) / rings);
+
+ for (int j = 0; j < sectors; j++) {
+ double lon0 = 2 * Math.PI * (double) j / sectors;
+ double lon1 = 2 * Math.PI * (double) (j + 1) / sectors;
+
+ Point3D p0 = sphericalToCartesian(center, radius, lat0, lon0);
+ Point3D p1 = sphericalToCartesian(center, radius, lat0, lon1);
+ Point3D p2 = sphericalToCartesian(center, radius, lat1, lon0);
+ Point3D p3 = sphericalToCartesian(center, radius, lat1, lon1);
+
+ if (i > 0) {
+ addShape(new SolidPolygon(p0, p2, p1, color));
+ }
+
+ if (i < rings - 1) {
+ addShape(new SolidPolygon(p2, p3, p1, color));
+ }
+ }
+ }
+
+ setBackfaceCulling(true);
+ }
+
+ private Point3D sphericalToCartesian(final Point3D center,
+ final double radius,
+ final double lat,
+ final double lon) {
+ double x = center.x + radius * Math.cos(lat) * Math.cos(lon);
+ double y = center.y + radius * Math.sin(lat);
+ double z = center.z + radius * Math.cos(lat) * Math.sin(lon);
+ return new Point3D(x, y, z);
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+
+/**
+ * Solid composite shapes built from SolidTriangle primitives.
+ *
+ * <p>These shapes render as filled surfaces with optional flat shading.
+ * Useful for creating opaque 3D objects like boxes, spheres, and cylinders.</p>
+ *
+ * <p>Key classes:</p>
+ * <ul>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.solid.SolidPolygonCube} - A solid cube</li>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.solid.SolidPolygonRectangularBox} - A solid box</li>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.solid.SolidPolygonSphere} - A solid sphere</li>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.solid.SolidPolygonCylinder} - A solid cylinder</li>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.solid.SolidPolygonPyramid} - A solid pyramid</li>
+ * </ul>
+ *
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.solid.SolidPolygonCube
+ */
+
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.solid;
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.textcanvas;
+
+import java.awt.Font;
+import java.awt.Graphics2D;
+import java.awt.RenderingHints;
+import java.awt.image.BufferedImage;
+import java.awt.image.DataBufferInt;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+import static eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.textcanvas.TextCanvas.FONT_CHAR_HEIGHT_TEXTURE_PIXELS;
+import static eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.textcanvas.TextCanvas.FONT_CHAR_WIDTH_TEXTURE_PIXELS;
+
+/**
+ * Per-glyph signed distance field (SDF) cache for sharp text rendering.
+ *
+ * <p>Instead of storing ink coverage (a photocopy of the glyph that blurs
+ * under any resampling), a distance field stores, per texel, the distance
+ * to the nearest glyph edge — negative inside the ink, positive outside.
+ * The rasterizer re-derives the edge per screen pixel from this smooth
+ * field, so text stays sharp at any magnification and degrades to clean
+ * gray under minification instead of aliasing.</p>
+ *
+ * <p>Each glyph is rendered at {@link #SUPERSAMPLE}x the cell resolution
+ * with anti-aliasing (giving the contour sub-texel precision), converted
+ * to a signed distance field by an exact Euclidean distance transform
+ * (Felzenszwalb & Huttenlocher separable EDT), clamped to
+ * {@link #SPREAD_TEXELS} texels of gradient around the edge, and
+ * downsampled by averaging to the cell size. Results are cached per
+ * character; stamping a glyph into a canvas mask is a small block copy.</p>
+ *
+ * <p>Mask values: 0 = deep inside ink, 127/128 = the edge, 255 = far
+ * outside any glyph. The matching coverage formula lives in
+ * {@code TexturedTriangle}'s SDF scanline path.</p>
+ *
+ * @see TextCanvas
+ */
+public final class SdfGlyphCache {
+
+ /**
+ * Width of the distance gradient around the glyph edge, in
+ * primary-texture texels. The normalized mask value 0.5 +/- 0.5 spans
+ * -SPREAD..+SPREAD texels of signed distance.
+ */
+ public static final double SPREAD_TEXELS = 2.0;
+
+ /**
+ * Glyph rasterization supersampling factor relative to the cell size.
+ */
+ private static final int SUPERSAMPLE = 4;
+
+ private static final int GLYPH_W = FONT_CHAR_WIDTH_TEXTURE_PIXELS;
+ private static final int GLYPH_H = FONT_CHAR_HEIGHT_TEXTURE_PIXELS;
+ private static final int HI_W = GLYPH_W * SUPERSAMPLE;
+ private static final int HI_H = GLYPH_H * SUPERSAMPLE;
+
+ /**
+ * Signed distance clamp range in hi-res pixels.
+ */
+ private static final float SPREAD_HI = (float) (SPREAD_TEXELS * SUPERSAMPLE);
+
+ /**
+ * Hi-res scratch font, sized to fit the scratch (see static init).
+ * Liberation Mono Bold is metric-compatible with Courier New (same
+ * 0.6em advance, so the cell grid is unchanged) but sans-serif with
+ * uniform sturdy strokes — Courier's serifs and thin strokes decay
+ * into unresolvable noise when the distance field is minified. Falls
+ * back to the logical Monospaced family.
+ */
+ private static final Font FONT_HI_SIZED;
+
+ /**
+ * Baseline offset in the hi-res scratch, chosen from the font's
+ * actual metrics so the tallest glyph fits vertically centered.
+ */
+ private static final int BASELINE_HI;
+
+ static {
+ Font family = new Font("Liberation Mono", Font.BOLD, 12);
+ if (!family.getFamily().toLowerCase().contains("liberation")) {
+ family = new Font("Monospaced", Font.BOLD, 12);
+ }
+
+ // Size the font so its metrics fit the scratch with margin:
+ // advance <= HI_W (wide glyphs must not clip the cell edge, which
+ // would corrupt the distance field there) and ascent+descent <=
+ // 95% of HI_H.
+ final BufferedImage probe = new BufferedImage(1, 1, BufferedImage.TYPE_INT_RGB);
+ final Graphics2D pg = probe.createGraphics();
+ int size = (int) (FONT_CHAR_HEIGHT_TEXTURE_PIXELS / 1.066) * SUPERSAMPLE;
+ int baseline = HI_H * 3 / 4;
+ while (size > 8) {
+ final Font f = family.deriveFont((float) size);
+ pg.setFont(f);
+ final java.awt.font.FontRenderContext frc = pg.getFontRenderContext();
+ double maxAdvance = 0;
+ for (char c = 33; c < 127; c++) {
+ maxAdvance = Math.max(maxAdvance,
+ f.getStringBounds(new char[]{c}, 0, 1, frc).getWidth());
+ }
+ final int ascent = pg.getFontMetrics().getMaxAscent();
+ final int descent = pg.getFontMetrics().getMaxDescent();
+ if (maxAdvance <= HI_W * 0.98 && ascent + descent <= HI_H * 0.95) {
+ baseline = (HI_H + ascent - descent) / 2;
+ break;
+ }
+ size--;
+ }
+ pg.dispose();
+ BASELINE_HI = baseline;
+ FONT_HI_SIZED = family.deriveFont((float) size);
+ }
+
+ private static final float INF = 1e15f;
+
+ private static final Map<Character, int[]> CACHE = new ConcurrentHashMap<>();
+
+ /**
+ * Serializes glyph rasterization: ConcurrentHashMap.computeIfAbsent
+ * locks per bin, so two threads generating DIFFERENT glyphs could
+ * otherwise enter generate() concurrently and use the shared static
+ * FONT_HI_SIZED at the same time. libfreetype does not tolerate
+ * concurrent scaler access — observed as a SIGSEGV in
+ * FreetypeFontScaler.getGlyphMetricsNative on the pty-reader thread
+ * (aukio terminal panel) racing another text canvas.
+ */
+ private static final Object FONT_RENDER_LOCK = new Object();
+
+ private SdfGlyphCache() {
+ }
+
+ /**
+ * Returns the cached {@link #GLYPH_W} x {@link #GLYPH_H} distance
+ * field for the given character, generating it on first access.
+ * Values 0 (inside ink) .. 255 (far outside), edge at ~127.5.
+ *
+ * @param c the character
+ * @return the glyph mask (row-major, one int per texel, do not modify)
+ */
+ public static int[] glyphMask(final char c) {
+ return CACHE.computeIfAbsent(c, SdfGlyphCache::generate);
+ }
+
+ private static int[] generate(final char c) {
+ final int[] px;
+ synchronized (FONT_RENDER_LOCK) {
+ final BufferedImage scratch = new BufferedImage(HI_W, HI_H, BufferedImage.TYPE_INT_RGB);
+ final Graphics2D g = scratch.createGraphics();
+ g.setColor(java.awt.Color.BLACK);
+ g.fillRect(0, 0, HI_W, HI_H);
+ g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
+ g.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
+ g.setFont(FONT_HI_SIZED);
+ g.setColor(java.awt.Color.WHITE);
+ g.drawChars(new char[]{c}, 0, 1, 0, BASELINE_HI);
+ g.dispose();
+ px = ((DataBufferInt) scratch.getRaster().getDataBuffer()).getData();
+ }
+
+ final boolean[] ink = new boolean[HI_W * HI_H];
+ for (int i = 0; i < px.length; i++) {
+ ink[i] = (px[i] & 0xff) > 127;
+ }
+
+ // Distance to nearest ink pixel (meaningful outside the glyph)
+ // and to nearest background pixel (meaningful inside it).
+ final float[] dOut = edt(ink, HI_W, HI_H);
+ final boolean[] background = new boolean[ink.length];
+ for (int i = 0; i < ink.length; i++) {
+ background[i] = !ink[i];
+ }
+ final float[] dIn = edt(background, HI_W, HI_H);
+
+ // Signed distance, clamped to the spread and averaged down to
+ // cell resolution. Averaging the FIELD (not coverage) preserves
+ // the edge position under the downsample.
+ final int[] mask = new int[GLYPH_W * GLYPH_H];
+ for (int y = 0; y < GLYPH_H; y++) {
+ for (int x = 0; x < GLYPH_W; x++) {
+ float sum = 0;
+ for (int sy = 0; sy < SUPERSAMPLE; sy++) {
+ final int rowBase = (y * SUPERSAMPLE + sy) * HI_W;
+ for (int sx = 0; sx < SUPERSAMPLE; sx++) {
+ final int i = rowBase + x * SUPERSAMPLE + sx;
+ float signed = dOut[i] - dIn[i];
+ if (signed > SPREAD_HI) signed = SPREAD_HI;
+ else if (signed < -SPREAD_HI) signed = -SPREAD_HI;
+ sum += signed;
+ }
+ }
+ final float avg = sum / (SUPERSAMPLE * SUPERSAMPLE);
+ final int v = Math.round((avg / SPREAD_HI * 0.5f + 0.5f) * 255f);
+ mask[y * GLYPH_W + x] = 0xFF000000 | (v << 16) | (v << 8) | v;
+ }
+ }
+ return mask;
+ }
+
+ /**
+ * Exact squared Euclidean distance transform of the given feature
+ * mask via two separable 1-D passes (Felzenszwalb & Huttenlocher).
+ *
+ * @param feature true at feature (zero-distance) pixels
+ * @param w grid width
+ * @param h grid height
+ * @return per-pixel distance to the nearest feature pixel
+ */
+ private static float[] edt(final boolean[] feature, final int w, final int h) {
+ final float[] f = new float[w * h];
+ for (int i = 0; i < f.length; i++) {
+ f[i] = feature[i] ? 0f : INF;
+ }
+
+ final int maxDim = Math.max(w, h);
+ final int[] v = new int[maxDim];
+ final float[] z = new float[maxDim + 1];
+ final float[] colIn = new float[maxDim];
+ final float[] colOut = new float[maxDim];
+
+ final float[] d = new float[w * h];
+ for (int x = 0; x < w; x++) {
+ for (int y = 0; y < h; y++) {
+ colIn[y] = f[y * w + x];
+ }
+ edt1d(colIn, colOut, h, v, z);
+ for (int y = 0; y < h; y++) {
+ d[y * w + x] = colOut[y];
+ }
+ }
+ for (int y = 0; y < h; y++) {
+ System.arraycopy(d, y * w, colIn, 0, w);
+ edt1d(colIn, colOut, w, v, z);
+ System.arraycopy(colOut, 0, d, y * w, w);
+ }
+
+ for (int i = 0; i < d.length; i++) {
+ d[i] = (float) Math.sqrt(d[i]);
+ }
+ return d;
+ }
+
+ /**
+ * 1-D squared distance transform: d[q] = min over p of
+ * (q-p)^2 + f[p], via the lower envelope of parabolas.
+ */
+ private static void edt1d(final float[] f, final float[] d, final int n,
+ final int[] v, final float[] z) {
+ int k = 0;
+ v[0] = 0;
+ z[0] = Float.NEGATIVE_INFINITY;
+ z[1] = Float.POSITIVE_INFINITY;
+ for (int q = 1; q < n; q++) {
+ float s = ((f[q] + (float) q * q) - (f[v[k]] + (float) v[k] * v[k]))
+ / (2f * q - 2f * v[k]);
+ while (s <= z[k]) {
+ k--;
+ s = ((f[q] + (float) q * q) - (f[v[k]] + (float) v[k] * v[k]))
+ / (2f * q - 2f * v[k]);
+ }
+ k++;
+ v[k] = q;
+ z[k] = s;
+ z[k + 1] = Float.POSITIVE_INFINITY;
+ }
+ k = 0;
+ for (int q = 0; q < n; q++) {
+ while (z[k + 1] < q) {
+ k++;
+ }
+ final float dv = q - v[k];
+ d[q] = dv * dv + f[v[k]];
+ }
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.textcanvas;
+
+import eu.svjatoslav.aukio.e3d.gui.TextPointer;
+import eu.svjatoslav.aukio.e3d.math.Transform;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.TexturedRectangle;
+import eu.svjatoslav.aukio.e3d.renderer.raster.texture.Texture;
+import eu.svjatoslav.aukio.e3d.renderer.raster.texture.TextureBitmap;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.StringReader;
+
+import static eu.svjatoslav.aukio.e3d.renderer.raster.Color.BLACK;
+import static eu.svjatoslav.aukio.e3d.renderer.raster.Color.WHITE;
+
+/**
+ * A text rendering surface in 3D space that displays a grid of characters.
+ *
+ * <p>{@code TextCanvas} extends {@link TexturedRectangle} and renders a 2D grid of
+ * characters (rows and columns) onto a texture-mapped rectangle. Each character cell
+ * supports independent foreground and background colors.</p>
+ *
+ * <p>Characters are rendered using a monospace font at a fixed cell size
+ * ({@value #FONT_CHAR_WIDTH_TEXTURE_PIXELS} x {@value #FONT_CHAR_HEIGHT_TEXTURE_PIXELS}
+ * texture pixels per character). The texture is a signed distance field (SDF):
+ * the mask stores per-texel distance to the nearest glyph edge (generated once
+ * per character by {@link SdfGlyphCache} and stamped per cell), while the
+ * primary bitmap and a separate foreground layer carry the cell colors. The
+ * rasterizer re-derives glyph edges per screen pixel from the distance field,
+ * so text stays sharp at any zoom and any angle from a single render path.</p>
+ *
+ * <p><b>Usage example</b></p>
+ * <pre>{@code
+ * Transform location = new Transform(new Point3D(0, 0, 500));
+ * TextCanvas canvas = new TextCanvas(location, "Hello, World!",
+ * Color.WHITE, Color.BLACK);
+ * shapeCollection.addShape(canvas);
+ *
+ * // Or create a blank canvas and write to it
+ * TextCanvas blank = new TextCanvas(location, new TextPointer(10, 40),
+ * Color.GREEN, Color.BLACK);
+ * blank.locate(0, 0);
+ * blank.print("Line 1");
+ * blank.locate(1, 0);
+ * blank.print("Line 2");
+ * }</pre>
+ *
+ * @see SdfGlyphCache
+ * @see TexturedRectangle
+ */
+public class TextCanvas extends TexturedRectangle {
+
+ /**
+ * Font character width in world coordinates.
+ */
+ public static final int FONT_CHAR_WIDTH = 8;
+
+ /**
+ * Font character height in world coordinates.
+ */
+ public static final int FONT_CHAR_HEIGHT = 16;
+
+ /**
+ * Font character width in texture pixels.
+ */
+ public static final int FONT_CHAR_WIDTH_TEXTURE_PIXELS = 16;
+
+ /**
+ * Font character height in texture pixels.
+ */
+ public static final int FONT_CHAR_HEIGHT_TEXTURE_PIXELS = 32;
+
+ private final TextPointer size;
+ private final TextPointer cursorLocation = new TextPointer();
+ private Color backgroundColor = BLACK;
+ private Color foregroundColor = WHITE;
+
+ /**
+ * Creates a text canvas initialized with the given text string.
+ *
+ * <p>The canvas dimensions are automatically computed from the text content
+ * (number of lines determines rows, the longest line determines columns).</p>
+ *
+ * @param location the 3D transform positioning this canvas in the scene
+ * @param text the initial text content (may contain newlines for multiple rows)
+ * @param foregroundColor the default text color
+ * @param backgroundColor the default background color
+ */
+ public TextCanvas(final Transform location, final String text,
+ final Color foregroundColor, final Color backgroundColor) {
+ this(location, getTextDimensions(text), foregroundColor,
+ backgroundColor);
+ setText(text);
+ }
+
+ /**
+ * Creates a blank text canvas with the specified dimensions.
+ *
+ * <p>The canvas is initialized with spaces in every cell, filled with the
+ * specified background color. Characters can be written using
+ * {@link #putChar(char)}, {@link #print(String)}, or {@link #setText(String)}.</p>
+ *
+ * @param dimensions the grid size as a {@link TextPointer} where
+ * {@code row} is the number of rows and {@code column} is the number of columns
+ * @param location the 3D transform positioning this canvas in the scene
+ * @param foregroundColor the default text color
+ * @param backgroundColor the default background color
+ */
+ public TextCanvas(final Transform location, final TextPointer dimensions,
+ final Color foregroundColor, final Color backgroundColor) {
+ super(location);
+
+ size = dimensions;
+ final int columns = dimensions.column;
+ final int rows = dimensions.row;
+
+ this.backgroundColor = backgroundColor;
+ this.foregroundColor = foregroundColor;
+
+ // initialize underlying textured rectangle
+ initialize(
+ columns * FONT_CHAR_WIDTH,
+ rows * FONT_CHAR_HEIGHT,
+ columns * FONT_CHAR_WIDTH_TEXTURE_PIXELS,
+ rows * FONT_CHAR_HEIGHT_TEXTURE_PIXELS,
+ 0);
+
+ // SDF layers: the distance mask carries glyph SHAPES (bilinear
+ // sampled, footprint-scaled coverage at render time), the primary
+ // bitmap is the background color layer and sdfForeground the
+ // hard ink color layer.
+ getTexture().primaryBitmap.fillColor(backgroundColor);
+
+ final Texture texture = getTexture();
+ texture.sdfMask = new TextureBitmap(
+ columns * FONT_CHAR_WIDTH_TEXTURE_PIXELS,
+ rows * FONT_CHAR_HEIGHT_TEXTURE_PIXELS, 1);
+ texture.sdfMask.fillColor(WHITE); // 255 = far outside any glyph
+ texture.sdfForeground = new TextureBitmap(
+ columns * FONT_CHAR_WIDTH_TEXTURE_PIXELS,
+ rows * FONT_CHAR_HEIGHT_TEXTURE_PIXELS, 1);
+ texture.sdfForeground.fillColor(foregroundColor);
+ texture.sdfSpreadTexels = SdfGlyphCache.SPREAD_TEXELS;
+ }
+
+ /**
+ * Computes the row and column dimensions needed to fit the given text.
+ *
+ * @param text the text content (may contain newlines)
+ * @return a {@link TextPointer} where {@code row} is the number of lines and
+ * {@code column} is the length of the longest line
+ */
+ public static TextPointer getTextDimensions(final String text) {
+
+ final BufferedReader reader = new BufferedReader(new StringReader(text));
+
+ int rows = 0;
+ int columns = 0;
+
+ while (true) {
+ final String line;
+ try {
+ line = reader.readLine();
+ } catch (IOException e) {
+ throw new RuntimeException(e);
+ }
+
+ if (line == null)
+ return new TextPointer(rows, columns);
+
+ rows++;
+ columns = Math.max(columns, line.length());
+ }
+ }
+
+ /**
+ * Clears the entire canvas, resetting all characters to spaces with the default colors.
+ *
+ * <p>The SDF mask and both color layers are reset.</p>
+ */
+ public void clear() {
+ getTexture().primaryBitmap.fillColor(backgroundColor);
+ getTexture().sdfMask.fillColor(WHITE);
+ getTexture().sdfForeground.fillColor(foregroundColor);
+ }
+
+ private void drawCharToTexture(final int row, final int column,
+ final char character, final Color foreground) {
+ final Texture texture = getTexture();
+ final int px = column * FONT_CHAR_WIDTH_TEXTURE_PIXELS;
+ final int py = row * FONT_CHAR_HEIGHT_TEXTURE_PIXELS;
+
+ // Background and ink color layers: hard per-cell fills (sampled
+ // nearest; only where the SDF coverage selects them).
+ texture.primaryBitmap.drawRectangle(px, py,
+ px + FONT_CHAR_WIDTH_TEXTURE_PIXELS,
+ py + FONT_CHAR_HEIGHT_TEXTURE_PIXELS, backgroundColor);
+ texture.sdfForeground.drawRectangle(px, py,
+ px + FONT_CHAR_WIDTH_TEXTURE_PIXELS,
+ py + FONT_CHAR_HEIGHT_TEXTURE_PIXELS, foreground);
+
+ // Stamp the cached glyph distance field into the mask.
+ final int[] glyph = SdfGlyphCache.glyphMask(character);
+ final int[] dst = texture.sdfMask.pixels;
+ final int maskWidth = texture.sdfMask.width;
+ for (int gy = 0; gy < FONT_CHAR_HEIGHT_TEXTURE_PIXELS; gy++) {
+ System.arraycopy(glyph, gy * FONT_CHAR_WIDTH_TEXTURE_PIXELS,
+ dst, (py + gy) * maskWidth + px, FONT_CHAR_WIDTH_TEXTURE_PIXELS);
+ }
+ }
+
+ /**
+ * Returns the dimensions of this text canvas.
+ *
+ * @return a {@link TextPointer} where {@code row} is the number of rows
+ * and {@code column} is the number of columns
+ */
+ public TextPointer getSize() {
+ return size;
+ }
+
+ /**
+ * Moves the internal cursor to the specified row and column.
+ *
+ * <p>Subsequent calls to {@link #putChar(char)} and {@link #print(String)} will
+ * begin writing at this position.</p>
+ *
+ * @param row the target row (0-based)
+ * @param column the target column (0-based)
+ */
+ public void locate(final int row, final int column) {
+ cursorLocation.row = row;
+ cursorLocation.column = column;
+ }
+
+ /**
+ * Prints a string starting at the current cursor location, advancing the cursor after each character.
+ *
+ * <p>When the cursor reaches the end of a row, it wraps to the beginning of the next row.</p>
+ *
+ * @param text the text to print
+ * @see #locate(int, int)
+ */
+ public void print(final String text) {
+ for (int i = 0; i < text.length(); i++)
+ putChar(text.charAt(i));
+ }
+
+ /**
+ * Writes a character at the current cursor location and advances the cursor.
+ *
+ * <p>The cursor moves one column to the right. If it exceeds the row width,
+ * it wraps to column 0 of the next row.</p>
+ *
+ * @param character the character to write
+ */
+ public void putChar(final char character) {
+ putChar(cursorLocation, character);
+
+ cursorLocation.column++;
+ if (cursorLocation.column >= size.column) {
+ cursorLocation.column = 0;
+ cursorLocation.row++;
+ }
+ }
+
+ /**
+ * Writes a character at the specified row and column using the current foreground and background colors.
+ *
+ * <p>If the row or column is out of bounds, the call is silently ignored.</p>
+ *
+ * @param row the row index (0-based)
+ * @param column the column index (0-based)
+ * @param character the character to write
+ */
+ public void putChar(final int row, final int column, final char character) {
+ if (row < 0 || row >= size.row || column < 0 || column >= size.column)
+ return;
+
+ drawCharToTexture(row, column, character, foregroundColor);
+ }
+
+ /**
+ * Writes a character at the position specified by a {@link TextPointer}.
+ *
+ * @param location the row and column position
+ * @param character the character to write
+ */
+ public void putChar(final TextPointer location, final char character) {
+ putChar(location.row, location.column, character);
+ }
+
+ /**
+ * Sets the default background color for subsequent character writes.
+ *
+ * @param backgroundColor the new background color
+ */
+ public void setBackgroundColor(
+ final eu.svjatoslav.aukio.e3d.renderer.raster.Color backgroundColor) {
+ this.backgroundColor = backgroundColor;
+ }
+
+ /**
+ * Sets the default foreground (text) color for subsequent character writes.
+ *
+ * @param foregroundColor the new foreground color
+ */
+ public void setForegroundColor(
+ final eu.svjatoslav.aukio.e3d.renderer.raster.Color foregroundColor) {
+ this.foregroundColor = foregroundColor;
+ }
+
+ /**
+ * Replaces the entire canvas content with the given multi-line text string.
+ *
+ * <p>Each line of text (separated by newlines) is written to consecutive rows,
+ * starting from row 0. Characters beyond the canvas width are ignored.</p>
+ *
+ * @param text the text to display (may contain newline characters)
+ */
+ public void setText(final String text) {
+ final BufferedReader reader = new BufferedReader(new StringReader(text));
+
+ int row = 0;
+
+ while (true) {
+ final String line;
+ try {
+ line = reader.readLine();
+ } catch (IOException e) {
+ throw new RuntimeException(e);
+ }
+
+ if (line == null)
+ return;
+
+ int column = 0;
+ for (int i = 0; i < line.length(); i++) {
+ putChar(row, column, line.charAt(i));
+ column++;
+ }
+ row++;
+ }
+ }
+
+ /**
+ * Sets the foreground color of the whole canvas.
+ *
+ * <p>Fills the SDF ink color layer; cell shapes are untouched, so
+ * text content and background colors are preserved.</p>
+ *
+ * @param color the new foreground color
+ */
+ public void setTextColor(final Color color) {
+ getTexture().sdfForeground.fillColor(color);
+ }
+
+}
--- /dev/null
+/**
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ * <p>
+ *
+ * Text canvas is a 2D canvas that can be used to render text.
+ */
+
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.textcanvas;
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.wireframe;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.geometry.Rectangle;
+import eu.svjatoslav.aukio.e3d.math.Transform;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.line.LineAppearance;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape;
+
+/**
+ * A 2D grid of line segments lying in the XY plane (Z = 0 in local space).
+ * The grid is divided into configurable numbers of cells along the X and Y axes,
+ * producing a regular rectangular mesh of lines.
+ *
+ * <p>This shape is useful for rendering floors, walls, reference planes, or any
+ * flat surface that needs a grid overlay. The grid is positioned and oriented
+ * in world space using a {@link Transform}.</p>
+ *
+ * <p><b>Usage example:</b></p>
+ * <pre>{@code
+ * Transform transform = new Transform(new Point3D(0, 100, 0));
+ * Rectangle rect = new Rectangle(new Point2D(-500, -500), new Point2D(500, 500));
+ * LineAppearance appearance = new LineAppearance(1, Color.GRAY);
+ * Grid2D grid = new Grid2D(transform, rect, 10, 10, appearance);
+ * shapeCollection.addShape(grid);
+ * }</pre>
+ *
+ * @see Grid3D
+ * @see LineAppearance
+ * @see AbstractCompositeShape
+ */
+public class Grid2D extends AbstractCompositeShape {
+
+ /**
+ * Constructs a 2D grid in the XY plane with the specified dimensions and
+ * number of divisions.
+ *
+ * @param transform the transform defining the grid's position and orientation
+ * in world space
+ * @param rectangle the rectangular dimensions of the grid in local XY space
+ * @param xDivisionCount the number of divisions (cells) along the X axis;
+ * produces {@code xDivisionCount + 1} vertical lines
+ * @param yDivisionCount the number of divisions (cells) along the Y axis;
+ * produces {@code yDivisionCount + 1} horizontal lines
+ * @param appearance the line appearance (color, width) used for all grid lines
+ */
+ public Grid2D(final Transform transform, final Rectangle rectangle,
+ final int xDivisionCount, final int yDivisionCount,
+ final LineAppearance appearance) {
+
+ super(transform);
+
+ final double stepY = rectangle.getHeight() / yDivisionCount;
+ final double stepX = rectangle.getWidth() / xDivisionCount;
+
+ for (int ySlice = 0; ySlice <= yDivisionCount; ySlice++) {
+ final double y = (ySlice * stepY) + rectangle.getLowerY();
+
+ for (int xSlice = 0; xSlice <= xDivisionCount; xSlice++) {
+ final double x = (xSlice * stepX) + rectangle.getLowerX();
+
+ final Point3D p1 = new Point3D(x, y, 0);
+ final Point3D p2 = new Point3D(x + stepX, y, 0);
+ final Point3D p3 = new Point3D(x, y + stepY, 0);
+
+ if (xSlice < xDivisionCount)
+ addShape(appearance.getLine(p1, p2));
+
+ if (ySlice < yDivisionCount)
+ addShape(appearance.getLine(p1, p3));
+ }
+
+ }
+
+ }
+
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.wireframe;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.line.LineAppearance;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape;
+
+/**
+ * A 3D grid of line segments filling a rectangular volume defined by two
+ * diagonally opposite corner points. Lines run along all three axes (X, Y, and Z)
+ * at regular intervals determined by the step size.
+ *
+ * <p>At each grid intersection point, up to three line segments are created
+ * (one along each axis), forming a three-dimensional lattice.</p>
+ *
+ * <p>This shape is useful for visualizing 3D space, voxel boundaries, or
+ * spatial reference grids in a scene.</p>
+ *
+ * <p><b>Usage example:</b></p>
+ * <pre>{@code
+ * LineAppearance appearance = new LineAppearance(1, Color.GRAY);
+ * Point3D cornerA = new Point3D(-100, -100, -100);
+ * Point3D cornerB = new Point3D(100, 100, 100);
+ * Grid3D grid = new Grid3D(cornerA, cornerB, 50, appearance);
+ * shapeCollection.addShape(grid);
+ * }</pre>
+ *
+ * @see Grid2D
+ * @see LineAppearance
+ * @see AbstractCompositeShape
+ */
+public class Grid3D extends AbstractCompositeShape {
+
+ /**
+ * Constructs a 3D grid filling the volume between two diagonally opposite
+ * corner points.
+ *
+ * <p>The corner points do not need to be in any particular min/max order;
+ * the constructor automatically normalizes them so that grid generation
+ * always proceeds from minimum to maximum coordinates.</p>
+ *
+ * @param cornerA the first corner point defining the volume
+ * @param cornerB the diagonally opposite corner point
+ * @param step the spacing between grid lines along each axis; must be positive
+ * @param appearance the line appearance (color, width) used for all grid lines
+ */
+ public Grid3D(final Point3D cornerA, final Point3D cornerB, final double step,
+ final LineAppearance appearance) {
+
+ super();
+
+ // Determine actual min/max bounds (corners may be in any order)
+ final double minX = Math.min(cornerA.x, cornerB.x);
+ final double maxX = Math.max(cornerA.x, cornerB.x);
+ final double minY = Math.min(cornerA.y, cornerB.y);
+ final double maxY = Math.max(cornerA.y, cornerB.y);
+ final double minZ = Math.min(cornerA.z, cornerB.z);
+ final double maxZ = Math.max(cornerA.z, cornerB.z);
+
+ for (double x = minX; x <= maxX; x += step) {
+ for (double y = minY; y <= maxY; y += step) {
+ for (double z = minZ; z <= maxZ; z += step) {
+
+ final Point3D p = new Point3D(x, y, z);
+
+ // Line along X axis
+ if ((x + step) <= maxX) {
+ addShape(appearance.getLine(p, new Point3D(x + step, y, z)));
+ }
+
+ // Line along Y axis
+ if ((y + step) <= maxY) {
+ addShape(appearance.getLine(p, new Point3D(x, y + step, z)));
+ }
+
+ // Line along Z axis
+ if ((z + step) <= maxZ) {
+ addShape(appearance.getLine(p, new Point3D(x, y, z + step)));
+ }
+ }
+ }
+ }
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.wireframe;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.math.Matrix3x3;
+import eu.svjatoslav.aukio.e3d.math.Quaternion;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.line.LineAppearance;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape;
+
+/**
+ * A 3D wireframe arrow shape composed of a cylindrical body and a conical tip.
+ *
+ * <p>The arrow points from a start point to an end point, with the tip
+ * located at the end point. The wireframe consists of:</p>
+ * <ul>
+ * <li><b>Body:</b> Two circular rings connected by lines between corresponding vertices</li>
+ * <li><b>Tip:</b> A circular ring at the cone base with lines to the apex</li>
+ * </ul>
+ *
+ * <p><b>Usage example:</b></p>
+ * <pre>{@code
+ * // Create a red arrow pointing from origin to (100, -50, 200)
+ * LineAppearance appearance = new LineAppearance(2, Color.RED);
+ * WireframeArrow arrow = new WireframeArrow(
+ * new Point3D(0, 0, 0), // start point
+ * new Point3D(100, -50, 200), // end point
+ * 8, // body radius
+ * 20, // tip radius
+ * 40, // tip length
+ * 16, // segments
+ * appearance
+ * );
+ * shapeCollection.addShape(arrow);
+ * }</pre>
+ *
+ * @see WireframeCone
+ * @see WireframeCylinder
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.solid.SolidPolygonArrow
+ */
+public class WireframeArrow extends AbstractCompositeShape {
+
+/**
+ * Default number of segments for arrow smoothness.
+ */
+private static final int DEFAULT_SEGMENTS = 12;
+
+/**
+ * Default tip radius as a fraction of body radius (2.5x).
+ */
+private static final double TIP_RADIUS_FACTOR = 2.5;
+
+/**
+ * Default tip length as a fraction of body radius (5.0x).
+ */
+private static final double TIP_LENGTH_FACTOR = 5.0;
+
+/**
+ * Constructs a 3D wireframe arrow pointing from start to end with sensible defaults.
+ *
+ * <p>This simplified constructor automatically calculates the tip radius as
+ * 2.5 times the body radius, the tip length as 5 times the body radius, and
+ * uses 12 segments for smoothness. For custom tip dimensions or segment count,
+ * use the full constructor.</p>
+ *
+ * @param startPoint the origin point of the arrow (where the body starts)
+ * @param endPoint the destination point of the arrow (where the tip points to)
+ * @param bodyRadius the radius of the cylindrical body; tip dimensions are
+ * calculated automatically from this value
+ * @param appearance the line appearance (color, width) used for all lines
+ */
+public WireframeArrow(final Point3D startPoint, final Point3D endPoint,
+ final double bodyRadius, final LineAppearance appearance) {
+ this(startPoint, endPoint, bodyRadius,
+ bodyRadius * TIP_RADIUS_FACTOR,
+ bodyRadius * TIP_LENGTH_FACTOR,
+ DEFAULT_SEGMENTS, appearance);
+}
+
+/**
+ * Constructs a 3D wireframe arrow pointing from start to end with full control over all dimensions.
+ *
+ * <p>The arrow consists of a cylindrical body extending from the start point
+ * towards the end, and a conical tip at the end point. If the distance between
+ * start and end is less than or equal to the tip length, only the cone tip
+ * is rendered.</p>
+ *
+ * @param startPoint the origin point of the arrow (where the body starts)
+ * @param endPoint the destination point of the arrow (where the tip points to)
+ * @param bodyRadius the radius of the cylindrical body
+ * @param tipRadius the radius of the cone base at the tip
+ * @param tipLength the length of the conical tip
+ * @param segments the number of segments for cylinder and cone smoothness.
+ * Higher values create smoother arrows. Minimum is 3.
+ * @param appearance the line appearance (color, width) used for all lines
+ */
+public WireframeArrow(final Point3D startPoint, final Point3D endPoint,
+ final double bodyRadius, final double tipRadius,
+ final double tipLength, final int segments,
+ final LineAppearance appearance) {
+ super();
+
+ // Calculate direction and distance
+ final double dx = endPoint.x - startPoint.x;
+ final double dy = endPoint.y - startPoint.y;
+ final double dz = endPoint.z - startPoint.z;
+ final double distance = Math.sqrt(dx * dx + dy * dy + dz * dz);
+
+ // Handle degenerate case: start and end are the same point
+ if (distance < 0.001) {
+ return;
+ }
+
+ // Normalize direction vector
+ final double nx = dx / distance;
+ final double ny = dy / distance;
+ final double nz = dz / distance;
+
+ // Calculate rotation to align Y-axis with direction
+ // Default arrow points in -Y direction (apex at lower Y)
+ // We need to rotate from (0, -1, 0) to (nx, ny, nz)
+ final Quaternion rotation = createRotationFromYAxis(nx, ny, nz);
+ final Matrix3x3 rotMatrix = rotation.toMatrix();
+
+ // Calculate body length (distance minus tip)
+ final double bodyLength = Math.max(0, distance - tipLength);
+
+ // Build the arrow components
+ if (bodyLength > 0) {
+ addCylinderBody(startPoint, bodyRadius, bodyLength, segments, appearance, rotMatrix, nx, ny, nz);
+ }
+ addConeTip(endPoint, tipRadius, tipLength, segments, appearance, rotMatrix, nx, ny, nz);
+ }
+
+ /**
+ * Creates a quaternion that rotates from the -Y axis to the given direction.
+ *
+ * <p>The arrow by default points in the -Y direction. This method computes
+ * the rotation needed to align the arrow with the target direction vector.</p>
+ *
+ * @param nx normalized direction X component
+ * @param ny normalized direction Y component
+ * @param nz normalized direction Z component
+ * @return quaternion representing the rotation
+ */
+ private Quaternion createRotationFromYAxis(final double nx, final double ny, final double nz) {
+ // Default direction is -Y (0, -1, 0)
+ // Target direction is (nx, ny, nz)
+ // Dot product: 0*nx + (-1)*ny + 0*nz = -ny
+ final double dot = -ny;
+
+ // Check for parallel vectors
+ if (dot > 0.9999) {
+ // Direction is nearly -Y, no rotation needed
+ return Quaternion.identity();
+ }
+ if (dot < -0.9999) {
+ // Direction is nearly +Y, rotate 180° around X axis
+ return Quaternion.fromAxisAngle(new Point3D(1, 0, 0), Math.PI);
+ }
+
+ // Cross product: (0, -1, 0) x (nx, ny, nz) = (-nz, 0, nx)
+ // This gives the rotation axis
+ final double axisX = -nz;
+ final double axisY = 0;
+ final double axisZ = nx;
+ final double axisLength = Math.sqrt(axisX * axisX + axisY * axisY + axisZ * axisZ);
+ final double normalizedAxisX = axisX / axisLength;
+ final double normalizedAxisZ = axisZ / axisLength;
+
+ // Angle from dot product
+ final double angle = Math.acos(dot);
+
+ return Quaternion.fromAxisAngle(
+ new Point3D(normalizedAxisX, 0, normalizedAxisZ), angle);
+ }
+
+ /**
+ * Adds the cylindrical body of the arrow.
+ *
+ * <p><b>Local coordinate system:</b> The arrow points in -Y direction in local space.
+ * Therefore, local -Y is toward the tip (front), and local +Y is toward the start (back).</p>
+ *
+ * @param startPoint the origin of the arrow body
+ * @param radius the radius of the cylinder
+ * @param length the length of the cylinder
+ * @param segments the number of segments around the circumference
+ * @param appearance the line appearance
+ * @param rotMatrix the rotation matrix to apply
+ * @param dirX direction X component (for translation calculation)
+ * @param dirY direction Y component
+ * @param dirZ direction Z component
+ */
+ private void addCylinderBody(final Point3D startPoint, final double radius,
+ final double length, final int segments,
+ final LineAppearance appearance, final Matrix3x3 rotMatrix,
+ final double dirX, final double dirY, final double dirZ) {
+ // Cylinder center is at startPoint + (length/2) * direction
+ final double centerX = startPoint.x + (length / 2.0) * dirX;
+ final double centerY = startPoint.y + (length / 2.0) * dirY;
+ final double centerZ = startPoint.z + (length / 2.0) * dirZ;
+
+ // Generate ring vertices in local space, then rotate and translate
+ // Arrow points in -Y direction, so:
+ // - tipSideRing is at local -Y (toward arrow tip, front of cylinder)
+ // - startSideRing is at local +Y (toward arrow start, back of cylinder)
+ final Point3D[] tipSideRing = new Point3D[segments];
+ final Point3D[] startSideRing = new Point3D[segments];
+
+ final double halfLength = length / 2.0;
+
+ for (int i = 0; i < segments; i++) {
+ final double angle = 2.0 * Math.PI * i / segments;
+ final double localX = radius * Math.cos(angle);
+ final double localZ = radius * Math.sin(angle);
+
+ // Tip-side ring (at -halfLength in local Y = toward arrow tip)
+ final Point3D tipSideLocal = new Point3D(localX, -halfLength, localZ);
+ rotMatrix.transform(tipSideLocal, tipSideLocal);
+ tipSideLocal.x += centerX;
+ tipSideLocal.y += centerY;
+ tipSideLocal.z += centerZ;
+ tipSideRing[i] = tipSideLocal;
+
+ // Start-side ring (at +halfLength in local Y = toward arrow start)
+ final Point3D startSideLocal = new Point3D(localX, halfLength, localZ);
+ rotMatrix.transform(startSideLocal, startSideLocal);
+ startSideLocal.x += centerX;
+ startSideLocal.y += centerY;
+ startSideLocal.z += centerZ;
+ startSideRing[i] = startSideLocal;
+ }
+
+ // Create the circular rings
+ for (int i = 0; i < segments; i++) {
+ final int next = (i + 1) % segments;
+
+ // Tip-side ring line segment
+ addShape(appearance.getLine(
+ new Point3D(tipSideRing[i].x, tipSideRing[i].y, tipSideRing[i].z),
+ new Point3D(tipSideRing[next].x, tipSideRing[next].y, tipSideRing[next].z)));
+
+ // Start-side ring line segment
+ addShape(appearance.getLine(
+ new Point3D(startSideRing[i].x, startSideRing[i].y, startSideRing[i].z),
+ new Point3D(startSideRing[next].x, startSideRing[next].y, startSideRing[next].z)));
+ }
+
+ // Create vertical lines connecting the two rings
+ for (int i = 0; i < segments; i++) {
+ addShape(appearance.getLine(
+ new Point3D(tipSideRing[i].x, tipSideRing[i].y, tipSideRing[i].z),
+ new Point3D(startSideRing[i].x, startSideRing[i].y, startSideRing[i].z)));
+ }
+ }
+
+ /**
+ * Adds the conical tip of the arrow.
+ *
+ * <p><b>Local coordinate system:</b> In local space, the cone points in -Y direction
+ * (apex at lower Y). The base ring is at Y=0, and the apex is at Y=-length.</p>
+ *
+ * @param endPoint the position of the arrow tip (cone apex)
+ * @param radius the radius of the cone base
+ * @param length the length of the cone
+ * @param segments the number of segments around the circumference
+ * @param appearance the line appearance
+ * @param rotMatrix the rotation matrix to apply
+ * @param dirX direction X component
+ * @param dirY direction Y component
+ * @param dirZ direction Z component
+ */
+ private void addConeTip(final Point3D endPoint, final double radius,
+ final double length, final int segments,
+ final LineAppearance appearance, final Matrix3x3 rotMatrix,
+ final double dirX, final double dirY, final double dirZ) {
+ // Apex is at endPoint (the arrow tip)
+ // Base center is at endPoint - length * direction (toward arrow start)
+ final double baseCenterX = endPoint.x - length * dirX;
+ final double baseCenterY = endPoint.y - length * dirY;
+ final double baseCenterZ = endPoint.z - length * dirZ;
+
+ // Generate base ring vertices
+ // In local space, cone points in -Y direction, so base is at Y=0
+ final Point3D[] baseRing = new Point3D[segments];
+
+ for (int i = 0; i < segments; i++) {
+ final double angle = 2.0 * Math.PI * i / segments;
+ final double localX = radius * Math.cos(angle);
+ final double localZ = radius * Math.sin(angle);
+
+ // Base ring vertices at local Y=0
+ final Point3D local = new Point3D(localX, 0, localZ);
+ rotMatrix.transform(local, local);
+ local.x += baseCenterX;
+ local.y += baseCenterY;
+ local.z += baseCenterZ;
+ baseRing[i] = local;
+ }
+
+ // Apex point (the arrow tip)
+ final Point3D apex = new Point3D(endPoint.x, endPoint.y, endPoint.z);
+
+ // Create the circular base ring
+ for (int i = 0; i < segments; i++) {
+ final int next = (i + 1) % segments;
+ addShape(appearance.getLine(
+ new Point3D(baseRing[i].x, baseRing[i].y, baseRing[i].z),
+ new Point3D(baseRing[next].x, baseRing[next].y, baseRing[next].z)));
+ }
+
+ // Create lines from apex to each base vertex
+ for (int i = 0; i < segments; i++) {
+ addShape(appearance.getLine(
+ new Point3D(apex.x, apex.y, apex.z),
+ new Point3D(baseRing[i].x, baseRing[i].y, baseRing[i].z)));
+ }
+ }
+}
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.wireframe;
+
+import eu.svjatoslav.aukio.e3d.geometry.Box;
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.line.LineAppearance;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape;
+
+/**
+ * A wireframe box (rectangular parallelepiped) composed of 12 line segments
+ * representing the edges of the box. The box is axis-aligned, defined by two
+ * diagonally opposite corner points.
+ *
+ * <p>The wireframe consists of four edges along each axis: four edges parallel
+ * to X, four parallel to Y, and four parallel to Z.</p>
+ *
+ * <p><b>Vertex layout:</b></p>
+ * <pre>
+ * cornerB (max) ────────┐
+ * /│ /│
+ * / │ / │
+ * / │ / │
+ * ┌───┼───────────┐ │
+ * │ │ │ │
+ * │ │ │ │
+ * │ └───────────│───┘
+ * │ / │ /
+ * │ / │ /
+ * │/ │/
+ * └───────────────┘ cornerA (min)
+ * </pre>
+ *
+ * <p><b>Usage example:</b></p>
+ * <pre>{@code
+ * LineAppearance appearance = new LineAppearance(2, Color.GREEN);
+ * Point3D cornerA = new Point3D(-50, -50, -50);
+ * Point3D cornerB = new Point3D(50, 50, 50);
+ * WireframeBox box = new WireframeBox(cornerA, cornerB, appearance);
+ * shapeCollection.addShape(box);
+ * }</pre>
+ *
+ * @see WireframeCube
+ * @see Box
+ * @see LineAppearance
+ * @see AbstractCompositeShape
+ */
+public class WireframeBox extends AbstractCompositeShape {
+
+ /**
+ * Constructs a wireframe box from a {@link Box} geometry object.
+ *
+ * @param box the axis-aligned box defining the two opposite corners
+ * @param appearance the line appearance (color, width) used for all 12 edges
+ */
+ public WireframeBox(final Box box,
+ final LineAppearance appearance) {
+
+ this(box.p1, box.p2, appearance);
+ }
+
+ /**
+ * Constructs a wireframe box from two diagonally opposite corner points.
+ * The corners do not need to be in any particular min/max order; the constructor
+ * uses each coordinate independently to form all eight vertices of the box.
+ *
+ * @param cornerA the first corner point of the box
+ * @param cornerB the diagonally opposite corner point of the box
+ * @param appearance the line appearance (color, width) used for all 12 edges
+ */
+ public WireframeBox(final Point3D cornerA, final Point3D cornerB,
+ final LineAppearance appearance) {
+ super();
+
+ // Determine actual min/max bounds (corners may be in any order)
+ final double minX = Math.min(cornerA.x, cornerB.x);
+ final double maxX = Math.max(cornerA.x, cornerB.x);
+ final double minY = Math.min(cornerA.y, cornerB.y);
+ final double maxY = Math.max(cornerA.y, cornerB.y);
+ final double minZ = Math.min(cornerA.z, cornerB.z);
+ final double maxZ = Math.max(cornerA.z, cornerB.z);
+
+ // Generate the 12 edges of the box
+ // Four edges along X axis (varying X, fixed Y and Z)
+ addShape(appearance.getLine(new Point3D(minX, minY, minZ), new Point3D(maxX, minY, minZ)));
+ addShape(appearance.getLine(new Point3D(minX, maxY, minZ), new Point3D(maxX, maxY, minZ)));
+ addShape(appearance.getLine(new Point3D(minX, minY, maxZ), new Point3D(maxX, minY, maxZ)));
+ addShape(appearance.getLine(new Point3D(minX, maxY, maxZ), new Point3D(maxX, maxY, maxZ)));
+
+ // Four edges along Y axis (varying Y, fixed X and Z)
+ addShape(appearance.getLine(new Point3D(minX, minY, minZ), new Point3D(minX, maxY, minZ)));
+ addShape(appearance.getLine(new Point3D(maxX, minY, minZ), new Point3D(maxX, maxY, minZ)));
+ addShape(appearance.getLine(new Point3D(minX, minY, maxZ), new Point3D(minX, maxY, maxZ)));
+ addShape(appearance.getLine(new Point3D(maxX, minY, maxZ), new Point3D(maxX, maxY, maxZ)));
+
+ // Four edges along Z axis (varying Z, fixed X and Y)
+ addShape(appearance.getLine(new Point3D(minX, minY, minZ), new Point3D(minX, minY, maxZ)));
+ addShape(appearance.getLine(new Point3D(maxX, minY, minZ), new Point3D(maxX, minY, maxZ)));
+ addShape(appearance.getLine(new Point3D(minX, maxY, minZ), new Point3D(minX, maxY, maxZ)));
+ addShape(appearance.getLine(new Point3D(maxX, maxY, minZ), new Point3D(maxX, maxY, maxZ)));
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.wireframe;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.math.Matrix3x3;
+import eu.svjatoslav.aukio.e3d.math.Quaternion;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.line.LineAppearance;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape;
+
+/**
+ * A wireframe cone that can be oriented in any direction.
+ *
+ * <p>The cone has a circular base and a single apex (tip) point. The wireframe
+ * consists of:</p>
+ * <ul>
+ * <li>A circular ring at the base</li>
+ * <li>Lines from each base vertex to the apex</li>
+ * </ul>
+ *
+ * <p>Two constructors are provided for different use cases:</p>
+ *
+ * <ul>
+ * <li><b>Directional (recommended):</b> Specify apex point and base center point.
+ * The cone points from apex toward the base center. This allows arbitrary
+ * orientation and is the most intuitive API.</li>
+ * <li><b>Y-axis aligned:</b> Specify base center, radius, and height. The cone
+ * points in -Y direction (apex at lower Y). Useful for simple vertical cones.</li>
+ * </ul>
+ *
+ * <p><b>Usage examples:</b></p>
+ * <pre>{@code
+ * // Directional constructor: cone pointing from apex toward base
+ * LineAppearance appearance = new LineAppearance(2, Color.RED);
+ * WireframeCone directionalCone = new WireframeCone(
+ * new Point3D(0, -100, 0), // apex (tip of the cone)
+ * new Point3D(0, 50, 0), // baseCenter (cone points toward this)
+ * 50, // radius of the circular base
+ * 16, // segments
+ * appearance
+ * );
+ *
+ * // Y-axis aligned constructor: cone pointing upward
+ * WireframeCone verticalCone = new WireframeCone(
+ * new Point3D(0, 0, 300), // baseCenter
+ * 50, // radius
+ * 100, // height
+ * 16, // segments
+ * appearance
+ * );
+ * }</pre>
+ *
+ * @see WireframeCylinder
+ * @see WireframeArrow
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.solid.SolidPolygonCone
+ */
+public class WireframeCone extends AbstractCompositeShape {
+
+ /**
+ * Constructs a wireframe cone pointing from apex toward base center.
+ *
+ * <p>This is the recommended constructor for placing cones in 3D space.
+ * The cone's apex (tip) is at {@code apexPoint}, and the circular base
+ * is centered at {@code baseCenterPoint}. The cone points in the direction
+ * from apex to base center.</p>
+ *
+ * <p><b>Coordinate interpretation:</b></p>
+ * <ul>
+ * <li>{@code apexPoint} - the sharp tip of the cone</li>
+ * <li>{@code baseCenterPoint} - the center of the circular base; the cone
+ * "points" in this direction from the apex</li>
+ * <li>The distance between apex and base center determines the cone height</li>
+ * </ul>
+ *
+ * @param apexPoint the position of the cone's tip (apex)
+ * @param baseCenterPoint the center point of the circular base; the cone
+ * points from apex toward this point
+ * @param radius the radius of the circular base
+ * @param segments the number of segments around the circumference.
+ * Higher values create smoother cones. Minimum is 3.
+ * @param appearance the line appearance (color, width) used for all lines
+ */
+ public WireframeCone(final Point3D apexPoint, final Point3D baseCenterPoint,
+ final double radius, final int segments,
+ final LineAppearance appearance) {
+ super();
+
+ // Calculate direction and height from apex to base center
+ final double dx = baseCenterPoint.x - apexPoint.x;
+ final double dy = baseCenterPoint.y - apexPoint.y;
+ final double dz = baseCenterPoint.z - apexPoint.z;
+ final double height = Math.sqrt(dx * dx + dy * dy + dz * dz);
+
+ // Handle degenerate case: apex and base center are the same point
+ if (height < 0.001) {
+ return;
+ }
+
+ // Normalize direction vector (from apex toward base)
+ final double nx = dx / height;
+ final double ny = dy / height;
+ final double nz = dz / height;
+
+ // Calculate rotation to align Y-axis with direction
+ // Default cone points in -Y direction (apex at origin, base at -Y)
+ // We need to rotate from (0, -1, 0) to (nx, ny, nz)
+ final Quaternion rotation = createRotationFromYAxis(nx, ny, nz);
+ final Matrix3x3 rotMatrix = rotation.toMatrix();
+
+ // Generate base ring vertices in local space, then rotate and translate
+ // In local space: apex is at origin, base is at Y = -height
+ // (cone points in -Y direction in local space)
+ final Point3D[] baseRing = new Point3D[segments];
+
+ for (int i = 0; i < segments; i++) {
+ final double angle = 2.0 * Math.PI * i / segments;
+ final double localX = radius * Math.cos(angle);
+ final double localZ = radius * Math.sin(angle);
+
+ // Base ring vertex in local space (Y = -height)
+ final Point3D local = new Point3D(localX, -height, localZ);
+ rotMatrix.transform(local, local);
+ local.x += apexPoint.x;
+ local.y += apexPoint.y;
+ local.z += apexPoint.z;
+ baseRing[i] = local;
+ }
+
+ // Apex point (the cone tip)
+ final Point3D apex = new Point3D(apexPoint.x, apexPoint.y, apexPoint.z);
+
+ // Create the circular base ring
+ for (int i = 0; i < segments; i++) {
+ final int next = (i + 1) % segments;
+ addShape(appearance.getLine(
+ new Point3D(baseRing[i].x, baseRing[i].y, baseRing[i].z),
+ new Point3D(baseRing[next].x, baseRing[next].y, baseRing[next].z)));
+ }
+
+ // Create lines from apex to each base vertex
+ for (int i = 0; i < segments; i++) {
+ addShape(appearance.getLine(
+ new Point3D(apex.x, apex.y, apex.z),
+ new Point3D(baseRing[i].x, baseRing[i].y, baseRing[i].z)));
+ }
+ }
+
+ /**
+ * Constructs a wireframe cone with circular base centered at the given point,
+ * pointing in the -Y direction.
+ *
+ * <p>This constructor creates a Y-axis aligned cone. The apex is positioned
+ * at {@code baseCenter.y - height} (above the base in the negative Y direction).
+ * For cones pointing in arbitrary directions, use
+ * {@link #WireframeCone(Point3D, Point3D, double, int, LineAppearance)} instead.</p>
+ *
+ * <p><b>Coordinate system:</b> The cone points in -Y direction (apex at lower Y).
+ * The base is at Y=baseCenter.y, and the apex is at Y=baseCenter.y - height.
+ * In Aukio 3D's coordinate system, "up" visually is negative Y.</p>
+ *
+ * @param baseCenter the center point of the cone's circular base in 3D space
+ * @param radius the radius of the circular base
+ * @param height the height of the cone from base center to apex
+ * @param segments the number of segments around the circumference.
+ * Higher values create smoother cones. Minimum is 3.
+ * @param appearance the line appearance (color, width) used for all lines
+ */
+ public WireframeCone(final Point3D baseCenter, final double radius,
+ final double height, final int segments,
+ final LineAppearance appearance) {
+ super();
+
+ // Apex is above the base (negative Y direction in this coordinate system)
+ final double apexY = baseCenter.y - height;
+ final Point3D apex = new Point3D(baseCenter.x, apexY, baseCenter.z);
+
+ // Generate vertices around the circular base
+ final Point3D[] baseRing = new Point3D[segments];
+ for (int i = 0; i < segments; i++) {
+ final double angle = 2.0 * Math.PI * i / segments;
+ final double x = baseCenter.x + radius * Math.cos(angle);
+ final double z = baseCenter.z + radius * Math.sin(angle);
+ baseRing[i] = new Point3D(x, baseCenter.y, z);
+ }
+
+ // Create the circular base ring
+ for (int i = 0; i < segments; i++) {
+ final int next = (i + 1) % segments;
+ addShape(appearance.getLine(
+ new Point3D(baseRing[i].x, baseRing[i].y, baseRing[i].z),
+ new Point3D(baseRing[next].x, baseRing[next].y, baseRing[next].z)));
+ }
+
+ // Create lines from apex to each base vertex
+ for (int i = 0; i < segments; i++) {
+ addShape(appearance.getLine(
+ new Point3D(apex.x, apex.y, apex.z),
+ new Point3D(baseRing[i].x, baseRing[i].y, baseRing[i].z)));
+ }
+ }
+
+ /**
+ * Creates a quaternion that rotates from the -Y axis to the given direction.
+ *
+ * <p>The cone by default points in the -Y direction (apex at origin, base at -Y).
+ * This method computes the rotation needed to align the cone with the target
+ * direction vector.</p>
+ *
+ * @param nx normalized direction X component
+ * @param ny normalized direction Y component
+ * @param nz normalized direction Z component
+ * @return quaternion representing the rotation
+ */
+ private Quaternion createRotationFromYAxis(final double nx, final double ny, final double nz) {
+ // Default direction is -Y (0, -1, 0)
+ // Target direction is (nx, ny, nz)
+ // Dot product: 0*nx + (-1)*ny + 0*nz = -ny
+ final double dot = -ny;
+
+ // Check for parallel vectors
+ if (dot > 0.9999) {
+ // Direction is nearly -Y, no rotation needed
+ return Quaternion.identity();
+ }
+ if (dot < -0.9999) {
+ // Direction is nearly +Y, rotate 180° around X axis
+ return Quaternion.fromAxisAngle(new Point3D(1, 0, 0), Math.PI);
+ }
+
+ // Cross product: (0, -1, 0) x (nx, ny, nz) = (-nz, 0, nx)
+ // This gives the rotation axis
+ final double axisX = -nz;
+ final double axisY = 0;
+ final double axisZ = nx;
+ final double axisLength = Math.sqrt(axisX * axisX + axisY * axisY + axisZ * axisZ);
+ final double normalizedAxisX = axisX / axisLength;
+ final double normalizedAxisZ = axisZ / axisLength;
+
+ // Angle from dot product
+ final double angle = Math.acos(dot);
+
+ return Quaternion.fromAxisAngle(
+ new Point3D(normalizedAxisX, 0, normalizedAxisZ), angle);
+ }
+}
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.wireframe;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.line.LineAppearance;
+
+/**
+ * A wireframe cube (equal-length sides) centered at a given point in 3D space.
+ * This is a convenience subclass of {@link WireframeBox} that constructs an
+ * axis-aligned cube from a center point and a half-side length.
+ *
+ * <p>The cube extends {@code size} units in each direction from the center,
+ * resulting in a total edge length of {@code 2 * size}.</p>
+ *
+ * <p><b>Usage example:</b></p>
+ * <pre>{@code
+ * LineAppearance appearance = new LineAppearance(1, Color.CYAN);
+ * WireframeCube cube = new WireframeCube(new Point3D(0, 0, 200), 50, appearance);
+ * shapeCollection.addShape(cube);
+ * }</pre>
+ *
+ * @see WireframeBox
+ * @see LineAppearance
+ */
+public class WireframeCube extends WireframeBox {
+
+ /**
+ * Constructs a wireframe cube centered at the given point.
+ *
+ * @param center the center point of the cube in 3D space
+ * @param size the half-side length; the cube extends this distance from
+ * the center along each axis, giving a total edge length
+ * of {@code 2 * size}
+ * @param appearance the line appearance (color, width) used for all 12 edges
+ */
+ public WireframeCube(final Point3D center, final double size,
+ final LineAppearance appearance) {
+ super(new Point3D(center.x - size, center.y - size, center.z - size),
+ new Point3D(center.x + size, center.y + size, center.z + size),
+ appearance);
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.wireframe;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.math.Matrix3x3;
+import eu.svjatoslav.aukio.e3d.math.Quaternion;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.line.LineAppearance;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape;
+
+/**
+ * A wireframe cylinder defined by two end points.
+ *
+ * <p>The cylinder extends from startPoint to endPoint with circular rings at both
+ * ends. The number of segments determines the smoothness of the circular rings.
+ * The wireframe consists of:</p>
+ * <ul>
+ * <li>Two circular rings at the start and end points</li>
+ * <li>Vertical lines connecting corresponding vertices between the rings</li>
+ * </ul>
+ *
+ * <p><b>Usage example:</b></p>
+ * <pre>{@code
+ * // Create a vertical cylinder from Y=100 to Y=200
+ * LineAppearance appearance = new LineAppearance(2, Color.RED);
+ * WireframeCylinder cylinder = new WireframeCylinder(
+ * new Point3D(0, 100, 0), // start point (bottom)
+ * new Point3D(0, 200, 0), // end point (top)
+ * 10, // radius
+ * 16, // segments
+ * appearance
+ * );
+ *
+ * // Create a horizontal cylinder along X axis
+ * WireframeCylinder pipe = new WireframeCylinder(
+ * new Point3D(-50, 0, 0),
+ * new Point3D(50, 0, 0),
+ * 5, 12, appearance
+ * );
+ * }</pre>
+ *
+ * @see WireframeCone
+ * @see WireframeArrow
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.solid.SolidPolygonCylinder
+ */
+public class WireframeCylinder extends AbstractCompositeShape {
+
+ /**
+ * Constructs a wireframe cylinder between two end points.
+ *
+ * <p>The cylinder has circular rings at both startPoint and endPoint,
+ * connected by lines between corresponding vertices. The orientation is
+ * automatically calculated from the direction between the two points.</p>
+ *
+ * @param startPoint the center of the first ring
+ * @param endPoint the center of the second ring
+ * @param radius the radius of the cylinder
+ * @param segments the number of segments around the circumference.
+ * Higher values create smoother cylinders. Minimum is 3.
+ * @param appearance the line appearance (color, width) used for all lines
+ */
+ public WireframeCylinder(final Point3D startPoint, final Point3D endPoint,
+ final double radius, final int segments,
+ final LineAppearance appearance) {
+ super();
+
+ // Calculate direction and distance
+ final double dx = endPoint.x - startPoint.x;
+ final double dy = endPoint.y - startPoint.y;
+ final double dz = endPoint.z - startPoint.z;
+ final double distance = Math.sqrt(dx * dx + dy * dy + dz * dz);
+
+ // Handle degenerate case: start and end are the same point
+ if (distance < 0.001) {
+ return;
+ }
+
+ // Normalize direction vector
+ final double nx = dx / distance;
+ final double ny = dy / distance;
+ final double nz = dz / distance;
+
+ // Calculate rotation to align Y-axis with direction
+ // Default cylinder is aligned along Y-axis
+ // We need to rotate from (0, 1, 0) to (nx, ny, nz)
+ final Quaternion rotation = createRotationFromYAxis(nx, ny, nz);
+ final Matrix3x3 rotMatrix = rotation.toMatrix();
+
+ // Cylinder center is at midpoint between start and end
+ final double centerX = (startPoint.x + endPoint.x) / 2.0;
+ final double centerY = (startPoint.y + endPoint.y) / 2.0;
+ final double centerZ = (startPoint.z + endPoint.z) / 2.0;
+ final double halfLength = distance / 2.0;
+
+ // Generate ring vertices in local space, then rotate and translate
+ // In local space: cylinder is aligned along Y-axis
+ // - startRing is at local -Y (toward startPoint)
+ // - endRing is at local +Y (toward endPoint)
+ final Point3D[] startRing = new Point3D[segments];
+ final Point3D[] endRing = new Point3D[segments];
+
+ for (int i = 0; i < segments; i++) {
+ final double angle = 2.0 * Math.PI * i / segments;
+ final double localX = radius * Math.cos(angle);
+ final double localZ = radius * Math.sin(angle);
+
+ // Start ring (at -halfLength in local Y = toward startPoint)
+ final Point3D startLocal = new Point3D(localX, -halfLength, localZ);
+ rotMatrix.transform(startLocal, startLocal);
+ startLocal.x += centerX;
+ startLocal.y += centerY;
+ startLocal.z += centerZ;
+ startRing[i] = startLocal;
+
+ // End ring (at +halfLength in local Y = toward endPoint)
+ final Point3D endLocal = new Point3D(localX, halfLength, localZ);
+ rotMatrix.transform(endLocal, endLocal);
+ endLocal.x += centerX;
+ endLocal.y += centerY;
+ endLocal.z += centerZ;
+ endRing[i] = endLocal;
+ }
+
+ // Create the circular rings
+ for (int i = 0; i < segments; i++) {
+ final int next = (i + 1) % segments;
+
+ // Start ring line segment
+ addShape(appearance.getLine(
+ new Point3D(startRing[i].x, startRing[i].y, startRing[i].z),
+ new Point3D(startRing[next].x, startRing[next].y, startRing[next].z)));
+
+ // End ring line segment
+ addShape(appearance.getLine(
+ new Point3D(endRing[i].x, endRing[i].y, endRing[i].z),
+ new Point3D(endRing[next].x, endRing[next].y, endRing[next].z)));
+ }
+
+ // Create vertical lines connecting the two rings
+ for (int i = 0; i < segments; i++) {
+ addShape(appearance.getLine(
+ new Point3D(startRing[i].x, startRing[i].y, startRing[i].z),
+ new Point3D(endRing[i].x, endRing[i].y, endRing[i].z)));
+ }
+ }
+
+ /**
+ * Creates a quaternion that rotates from the +Y axis to the given direction.
+ *
+ * @param nx normalized direction X component
+ * @param ny normalized direction Y component
+ * @param nz normalized direction Z component
+ * @return quaternion representing the rotation
+ */
+ private Quaternion createRotationFromYAxis(final double nx, final double ny, final double nz) {
+ // Default direction is +Y (0, 1, 0)
+ // Target direction is (nx, ny, nz)
+ // Dot product: 0*nx + 1*ny + 0*nz = ny
+ final double dot = ny;
+
+ // Check for parallel vectors
+ if (dot > 0.9999) {
+ // Direction is nearly +Y, no rotation needed
+ return Quaternion.identity();
+ }
+ if (dot < -0.9999) {
+ // Direction is nearly -Y, rotate 180° around X axis
+ return Quaternion.fromAxisAngle(new Point3D(1, 0, 0), Math.PI);
+ }
+
+ // Cross product: (0, 1, 0) x (nx, ny, nz) = (nz, 0, -nx)
+ // This gives the rotation axis
+ final double axisX = nz;
+ final double axisY = 0;
+ final double axisZ = -nx;
+ final double axisLength = Math.sqrt(axisX * axisX + axisY * axisY + axisZ * axisZ);
+ final double normalizedAxisX = axisX / axisLength;
+ final double normalizedAxisZ = axisZ / axisLength;
+
+ // Angle from dot product
+ final double angle = Math.acos(dot);
+
+ return Quaternion.fromAxisAngle(
+ new Point3D(normalizedAxisX, 0, normalizedAxisZ), angle);
+ }
+}
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.wireframe;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.math.Matrix3x3;
+import eu.svjatoslav.aukio.e3d.math.Quaternion;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.line.LineAppearance;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape;
+
+/**
+ * A wireframe square-based pyramid that can be oriented in any direction.
+ *
+ * <p>The pyramid has a square base and four triangular faces meeting at an apex
+ * (tip). The wireframe consists of:</p>
+ * <ul>
+ * <li>Four lines forming the square base</li>
+ * <li>Four lines from each base corner to the apex</li>
+ * </ul>
+ *
+ * <p>Two constructors are provided for different use cases:</p>
+ *
+ * <ul>
+ * <li><b>Directional (recommended):</b> Specify apex point and base center point.
+ * The pyramid points from apex toward the base center. This allows arbitrary
+ * orientation and is the most intuitive API.</li>
+ * <li><b>Y-axis aligned:</b> Specify base center, base size, and height. The pyramid
+ * points in -Y direction (apex at lower Y). Useful for simple vertical pyramids.</li>
+ * </ul>
+ *
+ * <p><b>Usage examples:</b></p>
+ * <pre>{@code
+ * // Directional constructor: pyramid pointing from apex toward base
+ * LineAppearance appearance = new LineAppearance(2, Color.RED);
+ * WireframePyramid directionalPyramid = new WireframePyramid(
+ * new Point3D(0, -100, 0), // apex (tip of the pyramid)
+ * new Point3D(0, 50, 0), // baseCenter (pyramid points toward this)
+ * 50, // baseSize (half-width of square base)
+ * appearance
+ * );
+ *
+ * // Y-axis aligned constructor: pyramid pointing upward
+ * WireframePyramid verticalPyramid = new WireframePyramid(
+ * new Point3D(0, 0, 300), // baseCenter
+ * 50, // baseSize (half-width of square base)
+ * 100, // height
+ * appearance
+ * );
+ * }</pre>
+ *
+ * @see WireframeCone
+ * @see WireframeCube
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.solid.SolidPolygonPyramid
+ */
+public class WireframePyramid extends AbstractCompositeShape {
+
+ /**
+ * Constructs a wireframe square-based pyramid pointing from apex toward base center.
+ *
+ * <p>This is the recommended constructor for placing pyramids in 3D space.
+ * The pyramid's apex (tip) is at {@code apexPoint}, and the square base
+ * is centered at {@code baseCenter}. The pyramid points in the direction
+ * from apex to base center.</p>
+ *
+ * <p><b>Coordinate interpretation:</b></p>
+ * <ul>
+ * <li>{@code apexPoint} - the sharp tip of the pyramid</li>
+ * <li>{@code baseCenter} - the center of the square base; the pyramid
+ * "points" in this direction from the apex</li>
+ * <li>{@code baseSize} - half the width of the square base; the base
+ * extends this distance from the center along perpendicular axes</li>
+ * <li>The distance between apex and base center determines the pyramid height</li>
+ * </ul>
+ *
+ * @param apexPoint the position of the pyramid's tip (apex)
+ * @param baseCenter the center point of the square base; the pyramid
+ * points from apex toward this point
+ * @param baseSize the half-width of the square base; the base extends
+ * this distance from the center, giving a total base
+ * edge length of {@code 2 * baseSize}
+ * @param appearance the line appearance (color, width) used for all lines
+ */
+ public WireframePyramid(final Point3D apexPoint, final Point3D baseCenter,
+ final double baseSize, final LineAppearance appearance) {
+ super();
+
+ // Calculate direction and height from apex to base center
+ final double dx = baseCenter.x - apexPoint.x;
+ final double dy = baseCenter.y - apexPoint.y;
+ final double dz = baseCenter.z - apexPoint.z;
+ final double height = Math.sqrt(dx * dx + dy * dy + dz * dz);
+
+ // Handle degenerate case: apex and base center are the same point
+ if (height < 0.001) {
+ return;
+ }
+
+ // Normalize direction vector (from apex toward base)
+ final double nx = dx / height;
+ final double ny = dy / height;
+ final double nz = dz / height;
+
+ // Calculate rotation to align Y-axis with direction
+ // Default pyramid points in -Y direction (apex at origin, base at -Y)
+ // We need to rotate from (0, -1, 0) to (nx, ny, nz)
+ final Quaternion rotation = createRotationFromYAxis(nx, ny, nz);
+ final Matrix3x3 rotMatrix = rotation.toMatrix();
+
+ // Generate base corner vertices in local space, then rotate and translate
+ // In local space: apex is at origin, base is at Y = -height
+ // Base corners form a square centered at (0, -height, 0)
+ final double h = baseSize;
+ final Point3D[] baseCorners = new Point3D[4];
+
+ // Local space corner positions (before rotation)
+ // Arranged counter-clockwise when viewed from apex (from +Y)
+ final double[][] localCorners = {
+ {-h, -height, -h}, // corner 0: negative X, negative Z
+ {+h, -height, -h}, // corner 1: positive X, negative Z
+ {+h, -height, +h}, // corner 2: positive X, positive Z
+ {-h, -height, +h} // corner 3: negative X, positive Z
+ };
+
+ for (int i = 0; i < 4; i++) {
+ final Point3D local = new Point3D(localCorners[i][0], localCorners[i][1], localCorners[i][2]);
+ rotMatrix.transform(local, local);
+ local.x += apexPoint.x;
+ local.y += apexPoint.y;
+ local.z += apexPoint.z;
+ baseCorners[i] = local;
+ }
+
+ // Apex point (the pyramid tip)
+ final Point3D apex = new Point3D(apexPoint.x, apexPoint.y, apexPoint.z);
+
+ // Create the four lines forming the square base
+ for (int i = 0; i < 4; i++) {
+ final int next = (i + 1) % 4;
+ addShape(appearance.getLine(
+ new Point3D(baseCorners[i].x, baseCorners[i].y, baseCorners[i].z),
+ new Point3D(baseCorners[next].x, baseCorners[next].y, baseCorners[next].z)));
+ }
+
+ // Create the four lines from apex to each base corner
+ for (int i = 0; i < 4; i++) {
+ addShape(appearance.getLine(
+ new Point3D(apex.x, apex.y, apex.z),
+ new Point3D(baseCorners[i].x, baseCorners[i].y, baseCorners[i].z)));
+ }
+ }
+
+ /**
+ * Constructs a wireframe square-based pyramid with base centered at the given point,
+ * pointing in the -Y direction.
+ *
+ * <p>This constructor creates a Y-axis aligned pyramid. The apex is positioned
+ * at {@code baseCenter.y - height} (above the base in the negative Y direction).
+ * For pyramids pointing in arbitrary directions, use
+ * {@link #WireframePyramid(Point3D, Point3D, double, LineAppearance)} instead.</p>
+ *
+ * <p><b>Coordinate system:</b> The pyramid points in -Y direction (apex at lower Y).
+ * The base is at Y=baseCenter.y, and the apex is at Y=baseCenter.y - height.
+ * In Aukio 3D's coordinate system, "up" visually is negative Y.</p>
+ *
+ * @param baseCenter the center point of the pyramid's base in 3D space
+ * @param baseSize the half-width of the square base; the base extends
+ * this distance from the center along X and Z axes,
+ * giving a total base edge length of {@code 2 * baseSize}
+ * @param height the height of the pyramid from base center to apex
+ * @param appearance the line appearance (color, width) used for all lines
+ */
+ public WireframePyramid(final Point3D baseCenter, final double baseSize,
+ final double height, final LineAppearance appearance) {
+ super();
+
+ final double halfBase = baseSize;
+ final double apexY = baseCenter.y - height;
+ final double baseY = baseCenter.y;
+
+ // Base corners arranged counter-clockwise when viewed from above (+Y)
+ // Naming: "negative/positive X" and "negative/positive Z" relative to base center
+ final Point3D negXnegZ = new Point3D(baseCenter.x - halfBase, baseY, baseCenter.z - halfBase);
+ final Point3D posXnegZ = new Point3D(baseCenter.x + halfBase, baseY, baseCenter.z - halfBase);
+ final Point3D posXposZ = new Point3D(baseCenter.x + halfBase, baseY, baseCenter.z + halfBase);
+ final Point3D negXposZ = new Point3D(baseCenter.x - halfBase, baseY, baseCenter.z + halfBase);
+ final Point3D apex = new Point3D(baseCenter.x, apexY, baseCenter.z);
+
+ // Create the four lines forming the square base
+ addShape(appearance.getLine(negXnegZ, posXnegZ));
+ addShape(appearance.getLine(posXnegZ, posXposZ));
+ addShape(appearance.getLine(posXposZ, negXposZ));
+ addShape(appearance.getLine(negXposZ, negXnegZ));
+
+ // Create the four lines from apex to each base corner
+ addShape(appearance.getLine(apex, negXnegZ));
+ addShape(appearance.getLine(apex, posXnegZ));
+ addShape(appearance.getLine(apex, posXposZ));
+ addShape(appearance.getLine(apex, negXposZ));
+ }
+
+ /**
+ * Creates a quaternion that rotates from the -Y axis to the given direction.
+ *
+ * <p>The pyramid by default points in the -Y direction (apex at origin, base at -Y).
+ * This method computes the rotation needed to align the pyramid with the target
+ * direction vector.</p>
+ *
+ * @param nx normalized direction X component
+ * @param ny normalized direction Y component
+ * @param nz normalized direction Z component
+ * @return quaternion representing the rotation
+ */
+ private Quaternion createRotationFromYAxis(final double nx, final double ny, final double nz) {
+ // Default direction is -Y (0, -1, 0)
+ // Target direction is (nx, ny, nz)
+ // Dot product: 0*nx + (-1)*ny + 0*nz = -ny
+ final double dot = -ny;
+
+ // Check for parallel vectors
+ if (dot > 0.9999) {
+ // Direction is nearly -Y, no rotation needed
+ return Quaternion.identity();
+ }
+ if (dot < -0.9999) {
+ // Direction is nearly +Y, rotate 180° around X axis
+ return Quaternion.fromAxisAngle(new Point3D(1, 0, 0), Math.PI);
+ }
+
+ // Cross product: (0, -1, 0) x (nx, ny, nz) = (-nz, 0, nx)
+ // This gives the rotation axis
+ final double axisX = -nz;
+ final double axisY = 0;
+ final double axisZ = nx;
+ final double axisLength = Math.sqrt(axisX * axisX + axisY * axisY + axisZ * axisZ);
+ final double normalizedAxisX = axisX / axisLength;
+ final double normalizedAxisZ = axisZ / axisLength;
+
+ // Angle from dot product
+ final double angle = Math.acos(dot);
+
+ return Quaternion.fromAxisAngle(
+ new Point3D(normalizedAxisX, 0, normalizedAxisZ), angle);
+ }
+}
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.wireframe;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.line.LineAppearance;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape;
+
+import java.util.ArrayList;
+
+/**
+ * A wireframe sphere approximation built from rings of connected line segments.
+ * The sphere is generated using parametric spherical coordinates, producing a
+ * latitude-longitude grid of vertices connected by lines.
+ *
+ * <p>The sphere is divided into 20 longitudinal slices and 20 latitudinal rings
+ * (using a step of {@code PI / 10} radians). Adjacent vertices within each ring
+ * are connected, and corresponding vertices between consecutive rings are also
+ * connected, forming a mesh that approximates a sphere surface.</p>
+ *
+ * <p><b>Usage example:</b></p>
+ * <pre>{@code
+ * LineAppearance appearance = new LineAppearance(1, Color.WHITE);
+ * WireframeSphere sphere = new WireframeSphere(new Point3D(0, 0, 300), 100f, appearance);
+ * shapeCollection.addShape(sphere);
+ * }</pre>
+ *
+ * @see LineAppearance
+ * @see AbstractCompositeShape
+ */
+public class WireframeSphere extends AbstractCompositeShape {
+
+ /** Stores the vertices of the previously generated ring for inter-ring connections. */
+ ArrayList<Point3D> previousRing = new ArrayList<>();
+
+ /**
+ * Constructs a wireframe sphere at the given location with the specified radius.
+ * The sphere is approximated by a grid of line segments generated from
+ * parametric spherical coordinates.
+ *
+ * @param location the center point of the sphere in 3D space
+ * @param radius the radius of the sphere
+ * @param lineFactory the line appearance (color, width) used for all line segments
+ */
+ public WireframeSphere(final Point3D location, final float radius,
+ final LineAppearance lineFactory) {
+ super(location);
+
+ final double step = Math.PI / 10;
+
+ final Point3D center = new Point3D();
+
+ int ringIndex = 0;
+
+ for (double j = 0d; j <= (Math.PI * 2); j += step) {
+
+ Point3D oldPoint = null;
+ int pointIndex = 0;
+
+ for (double i = 0; i <= (Math.PI * 2); i += step) {
+ final Point3D newPoint = new Point3D(0, 0, radius);
+ newPoint.rotate(center, i, j);
+
+ if (oldPoint != null)
+ addShape(lineFactory.getLine(newPoint, oldPoint));
+
+ if (ringIndex > 0) {
+ final Point3D previousRingPoint = previousRing
+ .get(pointIndex);
+ addShape(lineFactory.getLine(newPoint, previousRingPoint));
+
+ previousRing.set(pointIndex, newPoint);
+ } else
+ previousRing.add(newPoint);
+
+ oldPoint = newPoint;
+ pointIndex++;
+ }
+
+ ringIndex++;
+ }
+
+ }
+
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+
+/**
+ * Wireframe composite shapes built from Line primitives.
+ *
+ * <p>These shapes render as edge-only outlines, useful for visualization,
+ * debugging, and architectural-style rendering.</p>
+ *
+ * <p>Key classes:</p>
+ * <ul>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.wireframe.WireframeBox} - A wireframe box</li>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.wireframe.WireframeCube} - A wireframe cube</li>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.wireframe.WireframeSphere} - A wireframe sphere</li>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.wireframe.Grid2D} - A 2D grid plane</li>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.wireframe.Grid3D} - A 3D grid volume</li>
+ * </ul>
+ *
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.wireframe.WireframeBox
+ */
+
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.wireframe;
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+
+/**
+ * Renderable shape classes for the rasterization pipeline.
+ *
+ * <p>This package contains the shape hierarchy used for 3D rendering:</p>
+ * <ul>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.raster.shapes.AbstractShape} - Base class for all shapes</li>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.raster.shapes.AbstractCoordinateShape} - Base for shapes with vertices</li>
+ * </ul>
+ *
+ * <p>Subpackages organize shapes by type:</p>
+ * <ul>
+ * <li>{@code basic} - Primitive shapes (lines, polygons, billboards)</li>
+ * <li>{@code composite} - Compound shapes built from primitives (boxes, grids, text)</li>
+ * </ul>
+ *
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.shapes.AbstractShape
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.shapes.AbstractCoordinateShape
+ */
+
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes;
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.texture;
+
+import java.awt.*;
+import java.awt.image.BufferedImage;
+import java.awt.image.DataBufferInt;
+import java.awt.image.WritableRaster;
+
+import static java.util.Arrays.fill;
+
+/**
+ * Represents a 2D texture with mipmap support for level-of-detail rendering.
+ *
+ * <p>A {@code Texture} contains a primary bitmap at native resolution, along with
+ * cached upscaled and downscaled versions (mipmaps) that are lazily generated on demand.
+ * This mipmap chain enables efficient texture sampling at varying distances from the camera,
+ * avoiding aliasing artifacts for distant surfaces and pixelation for close-up views.</p>
+ *
+ * <p>The texture also exposes a {@link java.awt.Graphics2D} context backed by the primary
+ * bitmap's {@link java.awt.image.BufferedImage}, allowing dynamic rendering of text,
+ * shapes, or other 2D content directly onto the texture surface. Anti-aliasing is
+ * enabled by default on this graphics context.</p>
+ *
+ * <p><b>Mipmap levels</b></p>
+ * <ul>
+ * <li><b>Primary bitmap</b> -- the native resolution; always available.</li>
+ * <li><b>Downsampled bitmaps</b> -- up to 8 levels, each half the size of the previous.
+ * Used when the texture is rendered at zoom levels below 1.0.</li>
+ * <li><b>Upsampled bitmaps</b> -- configurable count (set at construction time), each
+ * double the size of the previous. Used when the texture is rendered at zoom levels
+ * above 2.0.</li>
+ * </ul>
+ *
+ * <p><b>Usage example</b></p>
+ * <pre>{@code
+ * Texture tex = new Texture(256, 256, 3);
+ * // Draw content using the Graphics2D context
+ * tex.graphics.setColor(java.awt.Color.RED);
+ * tex.graphics.fillRect(0, 0, 256, 256);
+ * // Invalidate cached mipmaps after modifying the primary bitmap
+ * tex.resetResampledBitmapCache();
+ * // Retrieve the appropriate mipmap for a given zoom level
+ * TextureBitmap bitmap = tex.getMipmapForScale(0.5);
+ * }</pre>
+ *
+ * @see TextureBitmap
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.texturedpolygon.TexturedTriangle
+ */
+public class Texture {
+
+ /**
+ * When true, texture coordinates outside [0, width/height) wrap
+ * (tile) instead of clamping to the edge texel. Needed for
+ * world-planar UVs and tiled game meshes.
+ */
+ public boolean wrap;
+
+ /**
+ * When true, this texture carries meaningful alpha (cutout TEST or
+ * BLEND): in z-buffer mode its triangles paint in the second,
+ * back-to-front alpha pass — depth-tested but not depth-written, so
+ * they resolve against opaque geometry per-pixel yet keep
+ * painter-coherent overlap among themselves. Opaque-class triangles
+ * paint first, front-to-back, writing depth. Set by texture
+ * providers that know the alpha mode (default false = opaque).
+ */
+ public boolean hasAlpha;
+
+ /**
+ * The primary (native resolution) bitmap for this texture.
+ * All dynamic drawing via {@link #graphics} modifies this bitmap's backing data.
+ */
+ public final TextureBitmap primaryBitmap;
+
+ /**
+ * A {@link java.awt.Graphics2D} context for drawing 2D content onto the primary bitmap.
+ * Anti-aliasing for both geometry and text is enabled by default.
+ */
+ public final java.awt.Graphics2D graphics;
+
+ /**
+ * Cached upsampled (enlarged) versions of the primary bitmap.
+ * Index 0 is 2x the primary, index 1 is 4x, and so on.
+ * Entries are lazily populated on first access.
+ */
+ TextureBitmap[] upSampled;
+
+ /**
+ * Cached downsampled (reduced) versions of the primary bitmap.
+ * Index 0 is 1/2 the primary, index 1 is 1/4, and so on.
+ * Entries are lazily populated on first access.
+ */
+ TextureBitmap[] downSampled = new TextureBitmap[8]; // TODO: consider renaming it to mipmap to use standard terminology
+
+ /**
+ * Optional signed-distance-field mask for sharp text/vector-art
+ * rendering. When non-null, {@code TexturedTriangle} samples this
+ * mask with bilinear filtering and derives per-pixel coverage from
+ * it (edge at value ~127.5), mixing the background layer
+ * ({@link #primaryBitmap}) with {@link #sdfForeground} — instead of
+ * blending coverage stored in the bitmap itself. The mask is always
+ * sampled at primary resolution: minification is handled by widening
+ * the coverage window by the pixel footprint, so no mipmap chain is
+ * needed and there is no mip-level isosurface drift.
+ *
+ * <p>Values: 0 = deep inside ink, 255 = far outside any ink.</p>
+ */
+ public TextureBitmap sdfMask;
+
+ /**
+ * Hard-edged foreground (ink) color layer for SDF rendering. Read
+ * only where the coverage derived from {@link #sdfMask} is non-zero,
+ * so flat per-region fills are sufficient; sampled nearest.
+ */
+ public TextureBitmap sdfForeground;
+
+ /**
+ * Width of the distance gradient encoded in {@link #sdfMask}, in
+ * primary-texture texels: mask value 0.5 +/- 0.5 spans
+ * -sdfSpreadTexels..+sdfSpreadTexels of signed distance. Set by
+ * whoever generated the mask (see {@code SdfGlyphCache#SPREAD_TEXELS}).
+ */
+ public double sdfSpreadTexels = 2.0;
+
+ /**
+ * Returns whether this texture renders through the SDF path
+ * (distance-field mask + separate bg/fg color layers).
+ *
+ * @return true when an SDF mask is attached
+ */
+ public boolean isSdf() {
+ return sdfMask != null;
+ }
+
+ /**
+ * Creates a new texture with the specified dimensions and upscale capacity.
+ *
+ * <p>The underlying {@link java.awt.image.BufferedImage} is created using
+ * {@link eu.svjatoslav.aukio.e3d.renderer.raster.RenderingContext#bufferedImageType} for
+ * compatibility with the raster rendering pipeline.</p>
+ *
+ * @param width the width of the primary bitmap in pixels
+ * @param height the height of the primary bitmap in pixels
+ * @param maxUpscale the maximum number of upscaled mipmap levels to support
+ * (each level doubles the resolution)
+ */
+ public Texture(final int width, final int height, final int maxUpscale) {
+ upSampled = new TextureBitmap[maxUpscale];
+
+ final BufferedImage bufferedImage = new BufferedImage(width, height,
+ BufferedImage.TYPE_INT_ARGB);
+
+ final WritableRaster raster = bufferedImage.getRaster();
+ final DataBufferInt dbi = (DataBufferInt) raster.getDataBuffer();
+ graphics = (Graphics2D) bufferedImage.getGraphics();
+
+ graphics.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
+ RenderingHints.VALUE_ANTIALIAS_ON);
+
+ graphics.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING,
+ RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
+
+ primaryBitmap = new TextureBitmap(width, height, dbi.getData(), 1);
+ }
+
+/**
+ * Determines the appropriate downscale mipmap level for a given scale factor.
+ *
+ * <p>Iterates through the downscaled mipmap levels (each halving the size)
+ * and returns the index of the first level whose effective size falls below
+ * the requested scale.</p>
+ *
+ * @param scale the scale factor (typically less than 1.0 for downscaling)
+ * @return the index into the {@code downSampled} array to use, clamped to the
+ * maximum available level
+ */
+ public int getDownscaleMipmapLevel(final double scale) {
+ double size = 1;
+ for (int i = 0; i < downSampled.length; i++) {
+ size = size / 2;
+ if (size < scale)
+ return i;
+ }
+
+ return downSampled.length - 1;
+ }
+
+ /**
+ * Determines the appropriate upscale mipmap level for a given scale factor.
+ *
+ * <p>Iterates through the upscaled mipmap levels (each doubling the size)
+ * and returns the index of the first level whose effective size exceeds
+ * the requested scale.</p>
+ *
+ * @param scale the scale factor (typically greater than 2.0 for upscaling)
+ * @return the index into the {@code upSampled} array to use, or -1 if no
+ * upscale is needed or available
+ */
+ public int getUpscaleMipmapLevel(final double scale) {
+ double size = 2;
+ for (int i = 0; i < upSampled.length; i++) {
+ size = size * 2;
+ if (size > scale)
+ return i;
+ }
+
+ return -1;
+ }
+
+ /**
+ * Downscale given bitmap by factor of 2.
+ *
+ * @param originalBitmap Bitmap to downscale.
+ * @return Downscaled bitmap.
+ */
+ public TextureBitmap downscaleBitmap(final TextureBitmap originalBitmap) {
+ int newWidth = originalBitmap.width / 2;
+ int newHeight = originalBitmap.height / 2;
+
+ // Enforce minimum width and height
+ if (newWidth < 1)
+ newWidth = 1;
+ if (newHeight < 1)
+ newHeight = 1;
+
+ final TextureBitmap downScaled = new TextureBitmap(newWidth, newHeight,
+ originalBitmap.multiplicationFactor / 2d);
+
+ final int[] srcPixels = originalBitmap.pixels;
+ final int[] dstPixels = downScaled.pixels;
+ final int srcW = originalBitmap.width;
+ final int srcH = originalBitmap.height;
+ final int srcWMinus1 = srcW - 1;
+ final int srcHMinus1 = srcH - 1;
+
+ for (int y = 0; y < newHeight; y++) {
+ final int srcYBase = y * 2;
+ final int srcY1 = Math.min(srcYBase, srcHMinus1);
+ final int srcY2 = Math.min(srcYBase + 1, srcHMinus1);
+ final int row1Offset = srcY1 * srcW;
+ final int row2Offset = srcY2 * srcW;
+
+ for (int x = 0; x < newWidth; x++) {
+ final int srcXBase = x * 2;
+ final int srcX1 = Math.min(srcXBase, srcWMinus1);
+ final int srcX2 = Math.min(srcXBase + 1, srcWMinus1);
+
+ final int p0 = srcPixels[row1Offset + srcX1];
+ final int p1 = srcPixels[row1Offset + srcX2];
+ final int p2 = srcPixels[row2Offset + srcX1];
+ final int p3 = srcPixels[row2Offset + srcX2];
+
+ final int a = (((p0 >>> 24) + (p1 >>> 24) + (p2 >>> 24) + (p3 >>> 24)) >> 2);
+ final int r = ((((p0 >> 16) & 0xff) + ((p1 >> 16) & 0xff) + ((p2 >> 16) & 0xff) + ((p3 >> 16) & 0xff)) >> 2);
+ final int g = ((((p0 >> 8) & 0xff) + ((p1 >> 8) & 0xff) + ((p2 >> 8) & 0xff) + ((p3 >> 8) & 0xff)) >> 2);
+ final int b = (((p0 & 0xff) + (p1 & 0xff) + (p2 & 0xff) + (p3 & 0xff)) >> 2);
+
+ dstPixels[y * newWidth + x] = (a << 24) | (r << 16) | (g << 8) | b;
+ }
+ }
+
+ return downScaled;
+ }
+
+ /**
+ * Returns a downscaled bitmap at the specified mipmap level, creating it lazily if needed.
+ *
+ * <p>Level 0 is half the primary resolution, level 1 is a quarter, and so on.
+ * Each level is derived by downscaling the previous level by a factor of 2.</p>
+ *
+ * @param scaleFactor the downscale level index (0 = 1/2 size, 1 = 1/4 size, etc.)
+ * @return the cached or newly created downscaled {@link TextureBitmap}
+ * @see #downscaleBitmap(TextureBitmap)
+ */
+ public TextureBitmap getDownscaledBitmap(final int scaleFactor) {
+ if (downSampled[scaleFactor] == null) {
+
+ TextureBitmap largerBitmap;
+ if (scaleFactor == 0)
+ largerBitmap = primaryBitmap;
+ else
+ largerBitmap = getDownscaledBitmap(scaleFactor - 1);
+
+ downSampled[scaleFactor] = downscaleBitmap(largerBitmap);
+ }
+
+ return downSampled[scaleFactor];
+ }
+
+ /**
+ * Returns the bitmap that should be used for rendering at the given zoom
+ *
+ * @param scaleFactor The upscale factor
+ * @return The bitmap
+ */
+ public TextureBitmap getUpscaledBitmap(final int scaleFactor) {
+ if (upSampled[scaleFactor] == null) {
+
+ TextureBitmap smallerBitmap;
+ if (scaleFactor == 0)
+ smallerBitmap = primaryBitmap;
+ else
+ smallerBitmap = getUpscaledBitmap(scaleFactor - 1);
+
+ upSampled[scaleFactor] = upscaleBitmap(smallerBitmap);
+ }
+
+ return upSampled[scaleFactor];
+ }
+
+ /**
+ * Returns the appropriate mipmap level for rendering at the given scale.
+ *
+ * <p>Scale factor represents how large the texture appears on screen
+ * relative to its native resolution:</p>
+ * <ul>
+ * <li>scale < 1.0: texture appears smaller (use downscaled mipmap)</li>
+ * <li>scale 1.0-2.0: texture appears near native size (use primary bitmap)</li>
+ * <li>scale > 2.0: texture appears much larger (use upscaled mipmap)</li>
+ * </ul>
+ *
+ * @param scale the apparent scale factor of the texture on screen
+ * @return the best-fit mipmap level as a {@link TextureBitmap}
+ */
+ public TextureBitmap getMipmapForScale(final double scale) {
+
+ if (scale < 1) {
+ final int mipmapLevel = getDownscaleMipmapLevel(scale);
+ return getDownscaledBitmap(mipmapLevel);
+ } else if (scale > 2) {
+ final int mipmapLevel = getUpscaleMipmapLevel(scale);
+
+ if (mipmapLevel < 0)
+ return primaryBitmap;
+
+ return getUpscaledBitmap(mipmapLevel);
+ }
+
+ return primaryBitmap;
+ }
+
+ /**
+ * Resets the cache of resampled bitmaps
+ */
+ public void resetResampledBitmapCache() {
+ fill(upSampled, null);
+
+ fill(downSampled, null);
+ }
+
+ /**
+ * Upscales the given bitmap by a factor of 2
+ *
+ * @param originalBitmap The bitmap to upscale
+ * @return The upscaled bitmap
+ */
+ public TextureBitmap upscaleBitmap(final TextureBitmap originalBitmap) {
+ final int srcW = originalBitmap.width;
+ final int srcH = originalBitmap.height;
+ final int newWidth = srcW * 2;
+ final int newHeight = srcH * 2;
+ final int srcWMinus1 = srcW - 1;
+ final int srcHMinus1 = srcH - 1;
+
+ final TextureBitmap upScaled = new TextureBitmap(newWidth, newHeight,
+ originalBitmap.multiplicationFactor * 2d);
+
+ final int[] src = originalBitmap.pixels;
+ final int[] dst = upScaled.pixels;
+
+ for (int y = 0; y < srcH; y++) {
+ final int srcRowOffset = y * srcW;
+ final int nextRowOffset = Math.min(y + 1, srcHMinus1) * srcW;
+ final int dstRow0Offset = (y * 2) * newWidth;
+ final int dstRow1Offset = (y * 2 + 1) * newWidth;
+
+ for (int x = 0; x < srcW; x++) {
+ final int nx = Math.min(x + 1, srcWMinus1);
+
+ final int p00 = src[srcRowOffset + x];
+ final int p10 = src[srcRowOffset + nx];
+ final int p01 = src[nextRowOffset + x];
+ final int p11 = src[nextRowOffset + nx];
+
+ dst[dstRow0Offset + x * 2] = p00;
+ dst[dstRow0Offset + x * 2 + 1] = avg2(p00, p10);
+ dst[dstRow1Offset + x * 2] = avg2(p00, p01);
+ dst[dstRow1Offset + x * 2 + 1] = avg4(p00, p10, p01, p11);
+ }
+ }
+
+ return upScaled;
+ }
+
+ private static int avg2(final int p0, final int p1) {
+ return (((((p0 >>> 24) + (p1 >>> 24)) >> 1) << 24)
+ | (((((p0 >> 16) & 0xff) + ((p1 >> 16) & 0xff)) >> 1) << 16)
+ | (((((p0 >> 8) & 0xff) + ((p1 >> 8) & 0xff)) >> 1) << 8)
+ | (((p0 & 0xff) + (p1 & 0xff)) >> 1));
+ }
+
+ private static int avg4(final int p0, final int p1, final int p2, final int p3) {
+ return ((((p0 >>> 24) + (p1 >>> 24) + (p2 >>> 24) + (p3 >>> 24)) >> 2) << 24)
+ | (((((p0 >> 16) & 0xff) + ((p1 >> 16) & 0xff) + ((p2 >> 16) & 0xff) + ((p3 >> 16) & 0xff)) >> 2) << 16)
+ | (((((p0 >> 8) & 0xff) + ((p1 >> 8) & 0xff) + ((p2 >> 8) & 0xff) + ((p3 >> 8) & 0xff)) >> 2) << 8)
+ | (((p0 & 0xff) + (p1 & 0xff) + (p2 & 0xff) + (p3 & 0xff)) >> 2);
+ }
+
+ /**
+ * A helper class that accumulates color values for a given area of a bitmap.
+ */
+ public static class ColorAccumulator {
+ /** Accumulated red component. */
+ public int r;
+ /** Accumulated green component. */
+ public int g;
+ /** Accumulated blue component. */
+ public int b;
+ /** Accumulated alpha component. */
+ public int a;
+
+ /** Number of pixels accumulated. */
+ public int pixelCount = 0;
+
+ /**
+ * Creates a new color accumulator with zero values.
+ */
+ public ColorAccumulator() {
+ }
+
+ /**
+ * Accumulates the color values of the given pixel
+ *
+ * @param bitmap The bitmap
+ * @param x The x coordinate of the pixel
+ * @param y The y coordinate of the pixel
+ */
+ public void accumulate(final TextureBitmap bitmap, final int x,
+ final int y) {
+ final int pixel = bitmap.pixels[bitmap.getAddress(x, y)];
+ a += (pixel >> 24) & 0xff;
+ r += (pixel >> 16) & 0xff;
+ g += (pixel >> 8) & 0xff;
+ b += pixel & 0xff;
+ pixelCount++;
+ }
+
+ /**
+ * Resets the accumulator
+ */
+ public void reset() {
+ a = 0;
+ r = 0;
+ g = 0;
+ b = 0;
+ pixelCount = 0;
+ }
+
+ /**
+ * Stores the accumulated color values in the given bitmap
+ *
+ * @param bitmap The bitmap
+ * @param x The x coordinate of the pixel
+ * @param y The y coordinate of the pixel
+ */
+ public void storeResult(final TextureBitmap bitmap, final int x,
+ final int y) {
+ final int avgA = a / pixelCount;
+ final int avgR = r / pixelCount;
+ final int avgG = g / pixelCount;
+ final int avgB = b / pixelCount;
+ bitmap.pixels[bitmap.getAddress(x, y)] = (avgA << 24) | (avgR << 16) | (avgG << 8) | avgB;
+ }
+ }
+
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.texture;
+
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+
+/**
+ * Represents a single resolution level of a texture as a raw int array.
+ *
+ * <p>Each pixel is stored as a single int in ARGB format:
+ * {@code (alpha << 24) | (red << 16) | (green << 8) | blue}.
+ * This matches the {@link java.awt.image.BufferedImage#TYPE_INT_ARGB} format.</p>
+ *
+ * <p>{@code TextureBitmap} is used internally by {@link Texture} to represent
+ * individual mipmap levels. The {@link #multiplicationFactor} records the
+ * scale ratio relative to the primary (native) resolution -- for example,
+ * a value of 0.5 means this bitmap is half the original size, and 2.0
+ * means it is double.</p>
+ *
+ * <p>This class provides low-level pixel operations including:</p>
+ * <ul>
+ * <li>Alpha-blended pixel transfer to a target raster ({@link #drawPixel(int, int[], int)})</li>
+ * <li>Direct pixel writes using engine {@link Color} ({@link #drawPixel(int, int, Color)})</li>
+ * <li>Filled rectangle drawing ({@link #drawRectangle(int, int, int, int, Color)})</li>
+ * <li>Full-surface color fill ({@link #fillColor(Color)})</li>
+ * </ul>
+ *
+ * @see Texture
+ * @see Color
+ */
+public class TextureBitmap {
+
+ /**
+ * Raw pixel data in ARGB int format.
+ * Each int encodes: {@code (alpha << 24) | (red << 16) | (green << 8) | blue}.
+ * The array length is {@code width * height}.
+ */
+ public final int[] pixels;
+
+ /**
+ * The width of this bitmap in pixels.
+ */
+ public final int width;
+
+ /**
+ * The height of this bitmap in pixels.
+ */
+ public final int height;
+
+ /**
+ * The scale factor of this bitmap relative to the primary (native) texture resolution.
+ * A value of 1.0 indicates the native resolution, 0.5 indicates half-size, 2.0 indicates double-size, etc.
+ */
+ public double multiplicationFactor;
+
+/**
+ * Creates a texture bitmap backed by an existing int array.
+ *
+ * <p>This constructor is typically used when the bitmap data is obtained from
+ * a {@link java.awt.image.BufferedImage}'s raster, allowing direct access to
+ * the image's pixel data without copying.</p>
+ *
+ * @param width the bitmap width in pixels
+ * @param height the bitmap height in pixels
+ * @param pixels the raw pixel data array (must be at least {@code width * height} ints)
+ * @param multiplicationFactor the scale factor relative to the native texture resolution
+ */
+ public TextureBitmap(final int width, final int height, final int[] pixels,
+ final double multiplicationFactor) {
+
+ this.width = width;
+ this.height = height;
+ this.pixels = pixels;
+ this.multiplicationFactor = multiplicationFactor;
+ }
+
+ /**
+ * Creates a texture bitmap with a newly allocated int array.
+ *
+ * <p>The pixel data array is initialized to all zeros (fully transparent black).</p>
+ *
+ * @param width the bitmap width in pixels
+ * @param height the bitmap height in pixels
+ * @param multiplicationFactor the scale factor relative to the native texture resolution
+ */
+ public TextureBitmap(final int width, final int height,
+ final double multiplicationFactor) {
+
+ this(width, height, new int[width * height], multiplicationFactor);
+ }
+
+ /**
+ * Transfer (render) one pixel from current {@link TextureBitmap} to target RGB raster.
+ *
+ * <p>This texture stores pixels in ARGB format. The target is RGB format (no alpha).
+ * Alpha blending is performed based on the source pixel's alpha value.</p>
+ *
+ * <p><b>Performance note:</b> Uses bit-shift instead of division for alpha blending,
+ * and pre-multiplies source colors to reduce per-pixel operations.</p>
+ *
+ * @param sourcePixelAddress Pixel index within current texture.
+ * @param targetBitmap Target RGB pixel array.
+ * @param targetPixelAddress Pixel index within target image.
+ */
+ public void drawPixel(final int sourcePixelAddress,
+ final int[] targetBitmap, final int targetPixelAddress) {
+
+ final int sourcePixel = pixels[sourcePixelAddress];
+ final int textureAlpha = (sourcePixel >> 24) & 0xff;
+
+ if (textureAlpha == 0)
+ return;
+
+ if (textureAlpha == 255) {
+ targetBitmap[targetPixelAddress] = sourcePixel;
+ return;
+ }
+
+ final int backgroundAlpha = 255 - textureAlpha;
+
+ // Pre-multiply source colors by alpha to reduce operations in blend
+ final int srcR = ((sourcePixel >> 16) & 0xff) * textureAlpha;
+ final int srcG = ((sourcePixel >> 8) & 0xff) * textureAlpha;
+ final int srcB = (sourcePixel & 0xff) * textureAlpha;
+
+ final int destPixel = targetBitmap[targetPixelAddress];
+ final int destR = (destPixel >> 16) & 0xff;
+ final int destG = (destPixel >> 8) & 0xff;
+ final int destB = destPixel & 0xff;
+
+ // Use bit-shift instead of division for faster blending
+ final int r = ((destR * backgroundAlpha) + srcR) >> 8;
+ final int g = ((destG * backgroundAlpha) + srcG) >> 8;
+ final int b = ((destB * backgroundAlpha) + srcB) >> 8;
+
+ targetBitmap[targetPixelAddress] = (r << 16) | (g << 8) | b;
+ }
+
+ /**
+ * Renders a scanline using pre-computed source pixel addresses.
+ *
+ * <p>This variant is optimized for cases where source addresses are computed
+ * externally (e.g., by a caller that already has the stepping logic).
+ * The sourceAddresses array must contain valid indices into {@link #pixels}.</p>
+ *
+ * @param sourceAddresses array of source pixel addresses (indices into pixels array)
+ * @param targetBitmap target RGB pixel array
+ * @param targetStartAddress starting index in the target array
+ * @param pixelCount number of pixels to render
+ */
+ public void drawScanlineWithAddresses(final int[] sourceAddresses,
+ final int[] targetBitmap, final int targetStartAddress,
+ final int pixelCount) {
+
+ int targetOffset = targetStartAddress;
+
+ for (int i = 0; i < pixelCount; i++) {
+ final int sourcePixel = pixels[sourceAddresses[i]];
+ final int textureAlpha = (sourcePixel >> 24) & 0xff;
+
+ if (textureAlpha == 255) {
+ targetBitmap[targetOffset] = sourcePixel;
+ } else if (textureAlpha != 0) {
+ final int backgroundAlpha = 255 - textureAlpha;
+
+ final int srcR = ((sourcePixel >> 16) & 0xff) * textureAlpha;
+ final int srcG = ((sourcePixel >> 8) & 0xff) * textureAlpha;
+ final int srcB = (sourcePixel & 0xff) * textureAlpha;
+
+ final int destPixel = targetBitmap[targetOffset];
+ final int destR = (destPixel >> 16) & 0xff;
+ final int destG = (destPixel >> 8) & 0xff;
+ final int destB = destPixel & 0xff;
+
+ final int r = ((destR * backgroundAlpha) + srcR) >> 8;
+ final int g = ((destG * backgroundAlpha) + srcG) >> 8;
+ final int b = ((destB * backgroundAlpha) + srcB) >> 8;
+
+ targetBitmap[targetOffset] = (r << 16) | (g << 8) | b;
+ }
+
+ targetOffset++;
+ }
+ }
+
+ /**
+ * Draws a single pixel at the specified coordinates using the given color.
+ *
+ * <p>The color components are written directly without alpha blending.
+ * Coordinates are clamped to the bitmap bounds by {@link #getAddress(int, int)}.</p>
+ *
+ * @param x the x coordinate of the pixel
+ * @param y the y coordinate of the pixel
+ * @param color the color to write
+ */
+ public void drawPixel(final int x, final int y, final Color color) {
+ pixels[getAddress(x, y)] = (color.a << 24) | (color.r << 16) | (color.g << 8) | color.b;
+ }
+
+ /**
+ * Fills a rectangular region with the specified color.
+ *
+ * <p>If {@code x1 > x2}, the coordinates are swapped to ensure correct rendering.
+ * The same applies to {@code y1} and {@code y2}. The rectangle is exclusive of the
+ * right and bottom edges.</p>
+ *
+ * <p><b>Performance:</b> Uses {@link java.util.Arrays#fill(int[], int, int, int)}
+ * per scanline for optimal JVM-optimized memory writes.</p>
+ *
+ * @param x1 the left x coordinate
+ * @param y1 the top y coordinate
+ * @param x2 the right x coordinate (exclusive)
+ * @param y2 the bottom y coordinate (exclusive)
+ * @param color the fill color
+ */
+ public void drawRectangle(int x1, int y1, int x2, int y2,
+ final Color color) {
+
+ if (x1 > x2) {
+ final int tmp = x1;
+ x1 = x2;
+ x2 = tmp;
+ }
+
+ if (y1 > y2) {
+ final int tmp = y1;
+ y1 = y2;
+ y2 = tmp;
+ }
+
+ // Clamp to bitmap bounds
+ if (x1 < 0) x1 = 0;
+ if (y1 < 0) y1 = 0;
+ if (x2 > width) x2 = width;
+ if (y2 > height) y2 = height;
+
+ final int pixel = (color.a << 24) | (color.r << 16) | (color.g << 8) | color.b;
+ final int rowWidth = x2 - x1;
+
+ if (rowWidth <= 0)
+ return;
+
+ // Fill each scanline using Arrays.fill for optimal performance
+ for (int y = y1; y < y2; y++) {
+ final int rowStart = y * width + x1;
+ java.util.Arrays.fill(pixels, rowStart, rowStart + rowWidth, pixel);
+ }
+ }
+
+ /**
+ * Fills the entire bitmap with the specified color.
+ *
+ * <p>Every pixel in the bitmap is set to the given color value,
+ * overwriting all existing content.</p>
+ *
+ * @param color the color to fill the entire bitmap with
+ */
+ public void fillColor(final Color color) {
+ final int pixel = (color.a << 24) | (color.r << 16) | (color.g << 8) | color.b;
+ java.util.Arrays.fill(pixels, pixel);
+ }
+
+ /**
+ * Computes the index into the {@link #pixels} array for the pixel at ({@code x}, {@code y}).
+ *
+ * <p>Coordinates are clamped to the valid range {@code [0, width-1]} and
+ * {@code [0, height-1]} so that out-of-bounds accesses are safely handled
+ * by sampling the nearest edge pixel.</p>
+ *
+ * @param x the x coordinate of the pixel
+ * @param y the y coordinate of the pixel
+ * @return the index into the pixels array for the specified pixel
+ */
+ public int getAddress(int x, int y) {
+ if (x < 0)
+ x = 0;
+
+ if (x >= width)
+ x = width - 1;
+
+ if (y < 0)
+ y = 0;
+
+ if (y >= height)
+ y = height - 1;
+
+ return (y * width) + x;
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.texture;
+
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+
+import java.lang.ref.WeakReference;
+import java.util.HashMap;
+import java.util.Map;
+
+import static java.lang.Math.pow;
+import static java.lang.Math.sqrt;
+
+/**
+ * Factory class for generating reusable textures with configurable borders and glow effects.
+ *
+ * <p>Provides static factory methods to create common texture patterns:</p>
+ * <ul>
+ * <li>{@link #solidWithBorder} - solid fill color with opaque border (for bordered polygons)</li>
+ * <li>{@link #glowingBorder} - transparent center with glowing edges (for wireframe-effect shapes)</li>
+ * <li>{@link #radialGlow} - circular radial gradient (for point/billboard glows)</li>
+ * </ul>
+ *
+ * <p><b>Texture caching:</b> Textures are cached by their generation parameters using a
+ * {@link WeakReference}-based cache. When textures are no longer referenced elsewhere,
+ * they are automatically garbage collected. This reduces memory usage when many shapes
+ * share identical textures.</p>
+ *
+ * <p><b>Example usage:</b></p>
+ * <pre>{@code
+ * // RGB cube plate with black border
+ * Texture tex1 = TextureGenerator.solidWithBorder(64, new Color(255, 0, 0), new Color(0, 0, 0), 3);
+ *
+ * // Wireframe-effect texture (glowing cyan edges, transparent center)
+ * Texture tex2 = TextureGenerator.glowingBorder(64, new Color(0, 255, 255), 6, 120, true);
+ *
+ * // Circular glow point
+ * Texture tex3 = TextureGenerator.radialGlow(100, new Color(255, 200, 100));
+ * }</pre>
+ *
+ * @see Texture
+ * @see Color
+ */
+public final class TextureGenerator {
+
+ /**
+ * Cache of generated textures, keyed by configuration parameters.
+ * Uses WeakReference so textures are GC'd when no longer referenced elsewhere.
+ */
+ private static final Map<TextureKey, WeakReference<Texture>> textureCache = new HashMap<>();
+
+ /**
+ * Private constructor to prevent instantiation.
+ * This class only provides static factory methods.
+ */
+ private TextureGenerator() {
+ }
+
+ /**
+ * Creates a texture with a solid fill color and an opaque border.
+ *
+ * <p>The fill color fills the entire texture except for the border region.
+ * The border is drawn as an opaque rectangle inset from the edges.</p>
+ *
+ * <p><b>Caching:</b> Identical parameters produce the same cached texture instance.</p>
+ *
+ * @param size the texture width and height in pixels
+ * @param fillColor the color filling the interior
+ * @param borderColor the color of the border
+ * @param borderWidth the width of the border in pixels
+ * @param maxUpscale the maximum number of upscaled mipmap levels (0 = no upscale, 1 = 2x upscale, 2 = 4x upscale)
+ * @return a texture with solid fill and opaque border
+ */
+ public static Texture solidWithBorder(final int size, final Color fillColor,
+ final Color borderColor, final int borderWidth,
+ final int maxUpscale) {
+ final TextureKey key = new TextureKey(size, fillColor, borderColor, borderWidth,
+ TextureType.SOLID_WITH_BORDER, 0, false, maxUpscale);
+
+ return getOrCreate(key, () -> generateSolidWithBorder(size, fillColor, borderColor, borderWidth, maxUpscale));
+ }
+
+ /**
+ * Creates a texture with a transparent center and glowing border edges.
+ *
+ * <p>This texture is useful for creating wireframe-effect shapes: the polygon
+ * appears to have only edges, with the interior being transparent. The border
+ * has a glow effect where intensity decreases from the edge toward the center.</p>
+ *
+ * <p><b>Glow effect:</b> Multiple concentric border lines are drawn with decreasing
+ * alpha values, creating a luminous edge appearance. The glow intensity controls
+ * how bright the innermost edge appears.</p>
+ *
+ * <p><b>Caching:</b> Identical parameters produce the same cached texture instance.</p>
+ *
+ * @param size the texture width and height in pixels
+ * @param borderColor the color of the glowing border
+ * @param borderWidth the width of the border region in pixels (where glow appears)
+ * @param glowIntensity the base intensity added to the border color (0-255 range)
+ * @param transparent if true, center is fully transparent; if false, has slight tint
+ * @param maxUpscale the maximum number of upscaled mipmap levels (0 = no upscale, 1 = 2x upscale, 2 = 4x upscale)
+ * @return a texture with glowing edges and transparent center
+ */
+ public static Texture glowingBorder(final int size, final Color borderColor,
+ final int borderWidth, final int glowIntensity,
+ final boolean transparent, final int maxUpscale) {
+ final TextureKey key = new TextureKey(size, borderColor, Color.TRANSPARENT, borderWidth,
+ TextureType.GLOWING_BORDER, glowIntensity, transparent, maxUpscale);
+
+ return getOrCreate(key, () -> generateGlowingBorder(size, borderColor, borderWidth,
+ glowIntensity, transparent, maxUpscale));
+ }
+
+ /**
+ * Creates a texture with a circular radial gradient glow.
+ *
+ * <p>The texture has a circular alpha gradient: fully opaque at the center,
+ * transitioning to fully transparent at the edges. The color intensity
+ * remains constant while alpha decreases radially.</p>
+ *
+ * <p>This is suitable for rendering glowing points or circular billboards.
+ * The center of the texture is the brightest point, fading outward.</p>
+ *
+ * <p><b>Caching:</b> Identical parameters produce the same cached texture instance.</p>
+ *
+ * @param size the texture width and height in pixels (should be even)
+ * @param color the color of the glow (alpha is overridden by radial gradient)
+ * @return a texture with circular radial alpha gradient
+ */
+ public static Texture radialGlow(final int size, final Color color) {
+ final TextureKey key = new TextureKey(size, color, Color.TRANSPARENT, 0,
+ TextureType.RADIAL_GLOW, 0, false, 1);
+
+ return getOrCreate(key, () -> generateRadialGlow(size, color));
+ }
+
+ /**
+ * Retrieves a cached texture or creates a new one if not cached.
+ *
+ * @param key the cache key identifying the texture configuration
+ * @param generator the function to create the texture if not cached
+ * @return the cached or newly created texture
+ */
+ private static Texture getOrCreate(final TextureKey key, final TextureSupplier generator) {
+ synchronized (textureCache) {
+ final WeakReference<Texture> ref = textureCache.get(key);
+ if (ref != null) {
+ final Texture cached = ref.get();
+ if (cached != null) {
+ return cached;
+ }
+ // Reference was cleared, remove stale entry
+ textureCache.remove(key);
+ }
+
+ final Texture texture = generator.create();
+ textureCache.put(key, new WeakReference<>(texture));
+ return texture;
+ }
+ }
+
+ /**
+ * Generates a texture with solid fill and opaque border.
+ */
+ private static Texture generateSolidWithBorder(final int size, final Color fillColor,
+ final Color borderColor, final int borderWidth,
+ final int maxUpscale) {
+ final Texture texture = new Texture(size, size, maxUpscale);
+
+ // Fill interior with fill color
+ texture.primaryBitmap.drawRectangle(borderWidth, borderWidth,
+ size - borderWidth, size - borderWidth, fillColor);
+
+ // Draw border regions (top, bottom, left, right edges)
+ // Top border
+ texture.primaryBitmap.drawRectangle(0, 0, size, borderWidth, borderColor);
+ // Bottom border
+ texture.primaryBitmap.drawRectangle(0, size - borderWidth, size, size, borderColor);
+ // Left border (excluding top/bottom corners already filled)
+ texture.primaryBitmap.drawRectangle(0, borderWidth, borderWidth, size - borderWidth, borderColor);
+ // Right border
+ texture.primaryBitmap.drawRectangle(size - borderWidth, borderWidth, size, size - borderWidth, borderColor);
+
+ texture.resetResampledBitmapCache();
+ return texture;
+ }
+
+ /**
+ * Generates a texture with glowing border and transparent center.
+ */
+ private static Texture generateGlowingBorder(final int size, final Color borderColor,
+ final int borderWidth, final int glowIntensity,
+ final boolean transparent, final int maxUpscale) {
+ final Texture texture = new Texture(size, size, maxUpscale);
+
+ // Clear to transparent or slight tint
+ final int centerAlpha = transparent ? 0 : 30;
+ final java.awt.Color bgColor = new java.awt.Color(borderColor.r, borderColor.g, borderColor.b, centerAlpha);
+ texture.graphics.setBackground(bgColor);
+ texture.graphics.clearRect(0, 0, size, size);
+
+ // Draw concentric glow lines from outer to inner
+ for (int i = 0; i < borderWidth; i++) {
+ final int intensity = (int) (glowIntensity * (borderWidth - i) / borderWidth);
+ final int alpha = Math.max(0, 200 - i * 30);
+
+ final java.awt.Color glowColor = new java.awt.Color(
+ Math.min(255, borderColor.r + intensity),
+ Math.min(255, borderColor.g + intensity),
+ Math.min(255, borderColor.b + intensity),
+ alpha
+ );
+
+ texture.graphics.setColor(glowColor);
+ texture.graphics.drawRect(i, i, size - 1 - 2 * i, size - 1 - 2 * i);
+ }
+
+ texture.graphics.dispose();
+ texture.resetResampledBitmapCache();
+ return texture;
+ }
+
+ /**
+ * Generates a texture with circular radial alpha gradient.
+ */
+ private static Texture generateRadialGlow(final int size, final Color color) {
+ final Texture texture = new Texture(size, size, 1);
+ final int halfSize = size / 2;
+
+ for (int x = 0; x < size; x++) {
+ for (int y = 0; y < size; y++) {
+ final int distanceFromCenter = (int) sqrt(pow(halfSize - x, 2) + pow(halfSize - y, 2));
+
+ int alpha = 255 - ((270 * distanceFromCenter) / halfSize);
+ if (alpha < 0) {
+ alpha = 0;
+ }
+
+ texture.primaryBitmap.pixels[texture.primaryBitmap.getAddress(x, y)] =
+ (alpha << 24) | (color.r << 16) | (color.g << 8) | color.b;
+ }
+ }
+
+ texture.resetResampledBitmapCache();
+ return texture;
+ }
+
+ /**
+ * Functional interface for texture creation.
+ */
+ @FunctionalInterface
+ private interface TextureSupplier {
+ Texture create();
+ }
+
+ /**
+ * Enumeration of texture generation types for cache key differentiation.
+ */
+ private enum TextureType {
+ SOLID_WITH_BORDER,
+ GLOWING_BORDER,
+ RADIAL_GLOW
+ }
+
+ /**
+ * Cache key for texture lookup based on generation parameters.
+ *
+ * <p>Two textures with identical parameters should produce the same key,
+ * enabling cache reuse. The key includes all parameters that affect
+ * the visual appearance of the generated texture.</p>
+ */
+ private static final class TextureKey {
+ private final int size;
+ private final Color primaryColor;
+ private final Color secondaryColor;
+ private final int borderWidth;
+ private final TextureType type;
+ private final int glowIntensity;
+ private final boolean transparent;
+ private final int maxUpscale;
+
+ TextureKey(final int size, final Color primaryColor, final Color secondaryColor,
+ final int borderWidth, final TextureType type, final int glowIntensity,
+ final boolean transparent, final int maxUpscale) {
+ this.size = size;
+ this.primaryColor = primaryColor;
+ this.secondaryColor = secondaryColor;
+ this.borderWidth = borderWidth;
+ this.type = type;
+ this.glowIntensity = glowIntensity;
+ this.transparent = transparent;
+ this.maxUpscale = maxUpscale;
+ }
+
+ @Override
+ public boolean equals(final Object o) {
+ if (this == o) return true;
+ if (o == null || getClass() != o.getClass()) return false;
+
+ final TextureKey that = (TextureKey) o;
+
+ if (size != that.size) return false;
+ if (borderWidth != that.borderWidth) return false;
+ if (glowIntensity != that.glowIntensity) return false;
+ if (transparent != that.transparent) return false;
+ if (maxUpscale != that.maxUpscale) return false;
+ if (type != that.type) return false;
+ if (!primaryColor.equals(that.primaryColor)) return false;
+ return secondaryColor.equals(that.secondaryColor);
+ }
+
+ @Override
+ public int hashCode() {
+ int result = size;
+ result = 31 * result + primaryColor.hashCode();
+ result = 31 * result + secondaryColor.hashCode();
+ result = 31 * result + borderWidth;
+ result = 31 * result + type.hashCode();
+ result = 31 * result + glowIntensity;
+ result = 31 * result + (transparent ? 1 : 0);
+ result = 31 * result + maxUpscale;
+ return result;
+ }
+ }
+}
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+
+/**
+ * Texture support with mipmap chains for level-of-detail rendering.
+ *
+ * <p>Textures provide 2D image data that can be mapped onto polygons. The mipmap
+ * system automatically generates scaled versions for efficient rendering at
+ * various distances.</p>
+ *
+ * <p>Key classes:</p>
+ * <ul>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.raster.texture.Texture} - Main texture class with mipmap support</li>
+ * <li>{@link eu.svjatoslav.aukio.e3d.renderer.raster.texture.TextureBitmap} - Raw pixel data for a single mipmap level</li>
+ * </ul>
+ *
+ * @see eu.svjatoslav.aukio.e3d.renderer.raster.texture.Texture
+ */
+
+package eu.svjatoslav.aukio.e3d.renderer.raster.texture;
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.cfg;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+import org.yaml.snakeyaml.Yaml;
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardCopyOption;
+import java.util.Map;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * Verifies {@link AukioConfig}: typed getters with defaults, mtime
+ * freshness on external edits, locked merge preserving hand edits,
+ * atomic concurrent writes, section flattening.
+ */
+public class AukioConfigTest {
+
+ @Rule
+ public TemporaryFolder tmp = new TemporaryFolder();
+
+ private Path newConfig(final String content) throws Exception {
+ final Path file = tmp.newFile("config.yaml").toPath();
+ Files.writeString(file, content);
+ return file;
+ }
+
+ /** Emulates an external writer (editor, other JVM): tmp + rename. */
+ private static void replaceAtomically(final Path file,
+ final String content)
+ throws Exception {
+ final Path swap = file.resolveSibling("swap-" + file.getFileName());
+ Files.writeString(swap, content);
+ Files.move(swap, file, StandardCopyOption.ATOMIC_MOVE,
+ StandardCopyOption.REPLACE_EXISTING);
+ }
+
+ @Test
+ public void missingFileYieldsDefaults() throws Exception {
+ final Path absent = tmp.getRoot().toPath().resolve("absent.yaml");
+ final AukioConfig cfg = AukioConfig.forFile(absent);
+ assertEquals("d", cfg.getString("any.key", "d"));
+ assertEquals(6.5, cfg.getDouble("any.key", 6.5), 0.0);
+ assertEquals(5, cfg.getInt("any.key", 5));
+ assertTrue(cfg.getBoolean("any.key", true));
+ assertTrue(cfg.getStringMap("fo4").isEmpty());
+ }
+
+ @Test
+ public void setCreatesMissingFileAndParents() throws Exception {
+ final Path nested = tmp.getRoot().toPath()
+ .resolve("sub/dir/config.yaml");
+ AukioConfig.forFile(nested).setString("app.state.lastEnv", "fo4");
+ assertEquals("fo4", AukioConfig.forFile(nested)
+ .getString("app.state.lastEnv", null));
+ }
+
+ @Test
+ public void typedGettersReadYamlScalars() throws Exception {
+ final Path file = newConfig(
+ "version: 1\ne3d:\n"
+ + " ipdCm: 6.3\n"
+ + " telemetryIntervalSeconds: 9\n"
+ + " logDir: /tmp/x\n"
+ + " stereo: true\n");
+ final AukioConfig cfg = AukioConfig.forFile(file);
+ assertEquals(6.3, cfg.getDouble("e3d.ipdCm", 0.0), 1e-9);
+ assertEquals(9, cfg.getInt("e3d.telemetryIntervalSeconds", 0));
+ assertEquals("/tmp/x", cfg.getString("e3d.logDir", null));
+ assertTrue(cfg.getBoolean("e3d.stereo", false));
+ assertEquals(6.5, cfg.getDouble("e3d.absent", 6.5), 0.0);
+ assertNull(cfg.getString("e3d.logDir.nested", null));
+ }
+
+ @Test
+ public void externalEditBecomesVisibleOnNextGet() throws Exception {
+ final Path file = newConfig("e3d:\n ipdCm: 6.1\n");
+ final AukioConfig cfg = AukioConfig.forFile(file);
+ assertEquals(6.1, cfg.getDouble("e3d.ipdCm", 0.0), 1e-9);
+ replaceAtomically(file, "e3d:\n ipdCm: 6.9\n");
+ assertEquals(6.9, cfg.getDouble("e3d.ipdCm", 0.0), 1e-9);
+ }
+
+ @Test
+ public void setMergesWithoutDroppingOtherKeys() throws Exception {
+ final Path file = newConfig("version: 1\nfo4:\n"
+ + " path: /games/FO4\n spawnAt: \"1,2,3,4\"\n");
+ final AukioConfig cfg = AukioConfig.forFile(file);
+ cfg.setDouble("e3d.ipdCm", 6.3);
+ final Map<String, Object> raw =
+ new Yaml().load(Files.readString(file));
+ final Map<String, Object> fo4 = cast(raw.get("fo4"));
+ assertEquals("/games/FO4", fo4.get("path"));
+ assertEquals("1,2,3,4", fo4.get("spawnAt"));
+ assertEquals(1, raw.get("version"));
+ assertEquals(6.3,
+ ((Map<String, Object>) raw.get("e3d")).get("ipdCm"));
+ }
+
+ @Test
+ public void setSurvivesInterleavedHandEdit() throws Exception {
+ final Path file = newConfig("fo4:\n path: /games/FO4\n"
+ + " spawnAt: \"1,2,3,4\"\ne3d:\n ipdCm: 6.1\n");
+ final AukioConfig cfg = AukioConfig.forFile(file);
+ cfg.setDouble("e3d.ipdCm", 6.3);
+ // user rewrites the file between the writer's read and write,
+ // changing fo4 values but keeping every section
+ replaceAtomically(file, "fo4:\n path: /other/FO4\n"
+ + " spawnAt: \"5,6,7,8\"\ne3d:\n ipdCm: 6.1\n");
+ cfg.setString("app.state.lastEnv", "fallout4");
+ final Map<String, Object> raw =
+ new Yaml().load(Files.readString(file));
+ final Map<String, Object> fo4 = cast(raw.get("fo4"));
+ assertEquals("hand edit must survive the app's write",
+ "/other/FO4", fo4.get("path"));
+ assertEquals("5,6,7,8", fo4.get("spawnAt"));
+ assertEquals(6.1,
+ ((Map<String, Object>) raw.get("e3d")).get("ipdCm"));
+ assertEquals("fallout4",
+ ((Map<String, Object>) ((Map<String, Object>)
+ raw.get("app")).get("state")).get("lastEnv"));
+ }
+
+ @Test
+ public void concurrentSetsFromManyThreadsAllPersist() throws Exception {
+ final Path file = newConfig("app:\n state: {}\n");
+ final AukioConfig cfg = AukioConfig.forFile(file);
+ final int threads = 8;
+ final int perThread = 25;
+ final ExecutorService pool = Executors.newFixedThreadPool(threads);
+ final CountDownLatch start = new CountDownLatch(1);
+ final java.util.List<java.util.concurrent.Future<?>> futures =
+ new java.util.ArrayList<>();
+ for (int t = 0; t < threads; t++) {
+ final int id = t;
+ futures.add(pool.submit(() -> {
+ try {
+ start.await();
+ for (int i = 0; i < perThread; i++)
+ cfg.setString("app.state.k" + id + "_" + i,
+ "v" + id + "_" + i);
+ } catch (final Exception e) {
+ throw new RuntimeException(e);
+ }
+ }));
+ }
+ start.countDown();
+ pool.shutdown();
+ assertTrue("writers finished in time",
+ pool.awaitTermination(60, TimeUnit.SECONDS));
+ for (final java.util.concurrent.Future<?> f : futures)
+ f.get(); // surface writer failures the pool would hide
+
+ final Map<String, Object> raw =
+ new Yaml().load(Files.readString(file));
+ final Map<String, Object> state = cast(
+ cast(raw.get("app")).get("state"));
+ assertEquals(threads * perThread, state.size());
+ for (int t = 0; t < threads; t++)
+ for (int i = 0; i < perThread; i++)
+ assertEquals("v" + t + "_" + i,
+ state.get("k" + t + "_" + i));
+ }
+
+ @Test
+ public void stringMapFlattensSectionScalars() throws Exception {
+ final Path file = newConfig("fo4:\n"
+ + " path: /games/FO4\n"
+ + " spawnAt: \"1,2,3,4\"\n"
+ + " nested:\n leaf: 7\n");
+ final Map<String, String> fo4 =
+ AukioConfig.forFile(file).getStringMap("fo4");
+ assertEquals("/games/FO4", fo4.get("path"));
+ assertEquals("1,2,3,4", fo4.get("spawnAt"));
+ assertEquals("7", fo4.get("nested.leaf"));
+ assertFalse(fo4.containsKey("absent"));
+ assertTrue(AukioConfig.forFile(file).getStringMap("absent")
+ .isEmpty());
+ }
+
+ @Test
+ public void samePathReturnsSameInstance() throws Exception {
+ final Path file = newConfig("e3d:\n ipdCm: 6.5\n");
+ assertTrue(AukioConfig.forFile(file)
+ == AukioConfig.forFile(file.toAbsolutePath().normalize()));
+ }
+
+ @SuppressWarnings("unchecked")
+ private static Map<String, Object> cast(final Object map) {
+ return (Map<String, Object>) map;
+ }
+}
--- /dev/null
+/*
+ * Aukio - System for data storage, computation, exploration and interaction.
+ * Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ *
+*/
+
+package eu.svjatoslav.aukio.e3d.gui.textEditorComponent;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class TextLineTest {
+
+ @Test
+ public void testAddIndent() {
+ TextLine textLine = new TextLine("test");
+ textLine.addIndent(4);
+ assertEquals(" test", textLine.toString());
+
+ textLine = new TextLine();
+ textLine.addIndent(4);
+ assertEquals("", textLine.toString());
+ }
+
+ @Test
+ public void testCutFromBeginning() {
+ TextLine textLine = new TextLine("test");
+ textLine.cutFromBeginning(2);
+ assertEquals("st", textLine.toString());
+
+ textLine = new TextLine("test");
+ textLine.cutFromBeginning(4);
+ assertEquals("", textLine.toString());
+
+ textLine = new TextLine("test");
+ textLine.cutFromBeginning(5);
+ assertEquals("", textLine.toString());
+
+ textLine = new TextLine("test");
+ textLine.cutFromBeginning(100);
+ assertEquals("", textLine.toString());
+ }
+
+ @Test
+ public void testCutSubString() {
+ TextLine textLine = new TextLine("test");
+ assertEquals("es", textLine.cutSubString(1, 3));
+ assertEquals("tt", textLine.toString());
+
+ textLine = new TextLine("test");
+ assertEquals("st ", textLine.cutSubString(2, 5));
+ assertEquals("te", textLine.toString());
+ }
+
+ @Test
+ public void testGetCharForLocation() {
+ final TextLine textLine = new TextLine("test");
+ assertEquals('s', textLine.getCharForLocation(2));
+ assertEquals('t', textLine.getCharForLocation(3));
+ assertEquals(' ', textLine.getCharForLocation(4));
+ }
+
+ @Test
+ public void testGetIndent() {
+ final TextLine textLine = new TextLine(" test");
+ assertEquals(3, textLine.getIndent());
+ }
+
+ @Test
+ public void testGetLength() {
+ final TextLine textLine = new TextLine("test");
+ assertEquals(4, textLine.getLength());
+ }
+
+ @Test
+ public void testInsertCharacter() {
+ TextLine textLine = new TextLine("test");
+ textLine.insertCharacter(1, 'o');
+ assertEquals("toest", textLine.toString());
+
+ textLine = new TextLine("test");
+ textLine.insertCharacter(5, 'o');
+ assertEquals("test o", textLine.toString());
+
+ }
+
+ @Test
+ public void testIsEmpty() {
+ TextLine textLine = new TextLine("");
+ assertEquals(true, textLine.isEmpty());
+
+ textLine = new TextLine(" ");
+ assertEquals(true, textLine.isEmpty());
+
+ textLine = new TextLine("l");
+ assertEquals(false, textLine.isEmpty());
+ }
+
+ @Test
+ public void testRemoveCharacter() {
+ TextLine textLine = new TextLine("test");
+ textLine.removeCharacter(0);
+ assertEquals("est", textLine.toString());
+
+ textLine = new TextLine("test");
+ textLine.removeCharacter(3);
+ assertEquals("tes", textLine.toString());
+
+ textLine = new TextLine("test");
+ textLine.removeCharacter(4);
+ assertEquals("test", textLine.toString());
+ }
+
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+
+/**
+ * Unit tests for the text editor component.
+ *
+ * <p>Tests for {@link eu.svjatoslav.aukio.e3d.gui.textEditorComponent.TextLine}
+ * and related text processing functionality.</p>
+ */
+
+package eu.svjatoslav.aukio.e3d.gui.textEditorComponent;
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.headless;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.geometry.Camera;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+import eu.svjatoslav.aukio.e3d.renderer.raster.ShapeCollection;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon.SolidPolygon;
+import org.junit.Test;
+
+import java.awt.image.BufferedImage;
+import java.io.File;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * Verifies the headless toolkit: pose parsing round-trip, snapshot
+ * rendering actually paints, pixel assertions agree with the render,
+ * golden comparison passes/fails deterministically.
+ */
+public class HeadlessToolkitTest {
+
+ /** A red triangle 100 units in front of the origin-facing camera. */
+ private static ShapeCollection triangleScene() {
+ final ShapeCollection scene = new ShapeCollection();
+ scene.addShape(new SolidPolygon(
+ new Point3D(-100, 0, 100), new Point3D(100, 0, 100),
+ new Point3D(0, 100, 100), Color.RED));
+ return scene;
+ }
+
+ @Test
+ public void poseRoundTrip() {
+ final Camera camera = Snapshot.cameraFromPose("290.31, -35.59, -2.10, -0.58, -0.15, -0.00");
+ final String pose = Snapshot.poseString(camera);
+ // parsed back, the pose string must be identical (same 2-decimal precision)
+ assertEquals("290.31, -35.59, -2.10, -0.58, -0.15, -0.00", pose);
+ }
+
+ @Test
+ public void renderPaintsTriangle() {
+ final BufferedImage image = Snapshot.render(triangleScene(), null,
+ "0, 0, 0, 0, 0, 0", 320, 240);
+ final long red = PixelAssertions.countColor(image, 0xFF0000);
+ assertTrue("red triangle should paint, redPixels=" + red, red > 5000);
+ assertTrue("most of the frame stays background",
+ PixelAssertions.unpaintedFraction(image, 0) > 0.5);
+ }
+
+ @Test
+ public void unpaintedFractionDetectsRegion() {
+ final BufferedImage image = Snapshot.render(triangleScene(), null,
+ "0, 0, 0, 0, 0, 0", 320, 240);
+ // the triangle is centered; corners must be unpainted
+ final double cornerBand = PixelAssertions.unpaintedFraction(image, 0, 0, 0, 0.1, 0.1);
+ assertEquals(1.0, cornerBand, 0.001);
+ }
+
+ @Test
+ public void goldenCompareExact() throws Exception {
+ final BufferedImage image = Snapshot.render(triangleScene(), null,
+ "0, 0, 0, 0, 0, 0", 320, 240);
+ final File golden = File.createTempFile("golden", ".png");
+ golden.deleteOnExit();
+ Snapshot.save(image, golden.getAbsolutePath());
+
+ final GoldenImage.Result exact = GoldenImage.compare(image, golden, 0, 0.0);
+ assertTrue(exact.toString(), exact.passed);
+ assertEquals(0, exact.diffPixels);
+
+ // paint one pixel differently: comparison must now fail at tolerance 0
+ image.setRGB(10, 10, 0x00FF00);
+ final GoldenImage.Result drifted = GoldenImage.compare(image, golden, 0, 0.0);
+ assertTrue(!drifted.passed);
+ assertEquals(1, drifted.diffPixels);
+
+ // ... but pass when one differing pixel is within the allowed fraction
+ final GoldenImage.Result tolerated = GoldenImage.compare(image, golden, 0, 0.001);
+ assertTrue(tolerated.toString(), tolerated.passed);
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.math;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class QuaternionTest {
+
+ @Test
+ public void testFromAnglesProducesValidMatrix() {
+ final Quaternion quaternion = Quaternion.fromAngles(0.5, 0.3);
+ final Matrix3x3 matrix = quaternion.toMatrix();
+
+ // Verify matrix is a valid rotation (determinant ≈ 1)
+ final double det = matrix.m00 * (matrix.m11 * matrix.m22 - matrix.m12 * matrix.m21)
+ - matrix.m01 * (matrix.m10 * matrix.m22 - matrix.m12 * matrix.m20)
+ + matrix.m02 * (matrix.m10 * matrix.m21 - matrix.m11 * matrix.m20);
+ assertEquals(1.0, det, 0.0001);
+ }
+
+ @Test
+ public void testToMatrixAliasesToMatrix3x3() {
+ final Quaternion quaternion = Quaternion.fromAngles(0.7, -0.4);
+ final Matrix3x3 m1 = quaternion.toMatrix();
+ final Matrix3x3 m2 = quaternion.toMatrix3x3();
+
+ final double epsilon = 0.0001;
+ assertEquals(m1.m00, m2.m00, epsilon);
+ assertEquals(m1.m01, m2.m01, epsilon);
+ assertEquals(m1.m02, m2.m02, epsilon);
+ assertEquals(m1.m10, m2.m10, epsilon);
+ assertEquals(m1.m11, m2.m11, epsilon);
+ assertEquals(m1.m12, m2.m12, epsilon);
+ assertEquals(m1.m20, m2.m20, epsilon);
+ assertEquals(m1.m21, m2.m21, epsilon);
+ assertEquals(m1.m22, m2.m22, epsilon);
+ }
+
+ @Test
+ public void testCloneProducesIndependentCopy() {
+ final Quaternion original = Quaternion.fromAngles(0.5, 0.3);
+ final Quaternion clone = original.clone();
+
+ assertEquals(original.w, clone.w, 0.0001);
+ assertEquals(original.x, clone.x, 0.0001);
+ assertEquals(original.y, clone.y, 0.0001);
+ assertEquals(original.z, clone.z, 0.0001);
+
+ // Modify original, verify clone is unaffected
+ final double originalW = original.w;
+ original.w = 0;
+ assertEquals(originalW, clone.w, 0.0001);
+ }
+
+}
\ No newline at end of file
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.math;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import org.junit.Test;
+
+import java.util.Random;
+
+import static org.junit.Assert.assertEquals;
+
+public class TransformStackTest {
+
+ private static final double EPSILON = 1e-6;
+
+ @Test
+ public void transformWithEmptyStackIsIdentity() {
+ final TransformStack stack = new TransformStack();
+ final Point3D p = new Point3D(10, 20, 30);
+ final Point3D result = new Point3D();
+
+ stack.transform(p, result);
+
+ assertEquals(p.x, result.x, EPSILON);
+ assertEquals(p.y, result.y, EPSILON);
+ assertEquals(p.z, result.z, EPSILON);
+ }
+
+ @Test
+ public void transformMatchesSequentialApplication() {
+ final Random rnd = new Random(42);
+
+ for (int depth = 1; depth <= 8; depth++) {
+ final Transform[] chain = new Transform[depth];
+ final TransformStack stack = new TransformStack();
+ for (int i = 0; i < depth; i++) {
+ chain[i] = Transform.fromAngles(
+ (rnd.nextDouble() - 0.5) * 1000,
+ (rnd.nextDouble() - 0.5) * 1000,
+ (rnd.nextDouble() - 0.5) * 1000,
+ (rnd.nextDouble() - 0.5) * Math.PI * 2,
+ (rnd.nextDouble() - 0.5) * Math.PI,
+ (rnd.nextDouble() - 0.5) * Math.PI);
+ stack.addTransform(chain[i]);
+ }
+
+ for (int k = 0; k < 100; k++) {
+ final Point3D p = new Point3D(
+ (rnd.nextDouble() - 0.5) * 2000,
+ (rnd.nextDouble() - 0.5) * 2000,
+ (rnd.nextDouble() - 0.5) * 2000);
+
+ // Oracle: documented semantics — transforms applied in reverse
+ // order of insertion (last added = first applied)
+ final Point3D expected = new Point3D(p);
+ for (int i = depth - 1; i >= 0; i--) {
+ chain[i].transform(expected);
+ }
+
+ final Point3D result = new Point3D();
+ stack.transform(p, result);
+
+ assertEquals("depth " + depth + " x", expected.x, result.x, EPSILON);
+ assertEquals("depth " + depth + " y", expected.y, result.y, EPSILON);
+ assertEquals("depth " + depth + " z", expected.z, result.z, EPSILON);
+ }
+ }
+ }
+
+ @Test
+ public void dropTransformRestoresParentState() {
+ final Transform a = Transform.fromAngles(100, 0, 0, 0.3, 0.1, 0);
+ final Transform b = Transform.fromAngles(0, 50, 0, 0, 0.5, 0.2);
+ final Transform c = Transform.fromAngles(0, 0, 500, 1.0, 0, 0.4);
+
+ final TransformStack stack = new TransformStack();
+ stack.addTransform(a);
+ stack.addTransform(b);
+ stack.dropTransform();
+ stack.addTransform(c);
+
+ final TransformStack reference = new TransformStack();
+ reference.addTransform(a);
+ reference.addTransform(c);
+
+ final Point3D p = new Point3D(7, -13, 42);
+ final Point3D result = new Point3D();
+ final Point3D expected = new Point3D();
+ stack.transform(p, result);
+ reference.transform(p, expected);
+
+ assertEquals(expected.x, result.x, EPSILON);
+ assertEquals(expected.y, result.y, EPSILON);
+ assertEquals(expected.z, result.z, EPSILON);
+ }
+
+ @Test
+ public void transformComposesEagerlyAtPushTime() {
+ final Transform transform = Transform.fromAngles(10, 20, 30, 0.5, 0.2, 0.1);
+
+ final TransformStack stack = new TransformStack();
+ stack.addTransform(transform);
+
+ // Expected result uses the values the transform had when pushed
+ final Point3D p = new Point3D(1, 2, 3);
+ final Point3D expected = new Point3D(p);
+ final Transform snapshot = transform.clone();
+ snapshot.transform(expected);
+
+ // Mutating the transform after pushing must NOT affect the stack:
+ // composition is an eager snapshot taken at push time
+ transform.set(-999, 888, -777, 2.5, -1.5, 0.9);
+
+ final Point3D result = new Point3D();
+ stack.transform(p, result);
+
+ assertEquals(expected.x, result.x, EPSILON);
+ assertEquals(expected.y, result.y, EPSILON);
+ assertEquals(expected.z, result.z, EPSILON);
+ }
+
+ @Test
+ public void clearResetsStackToIdentity() {
+ final TransformStack stack = new TransformStack();
+ stack.addTransform(Transform.fromAngles(1, 2, 3, 0.5, 0.2, 0.1));
+ stack.addTransform(Transform.fromAngles(4, 5, 6, 0.1, 0.9, 0.3));
+ stack.clear();
+
+ final Point3D p = new Point3D(10, 20, 30);
+ final Point3D result = new Point3D();
+ stack.transform(p, result);
+
+ assertEquals(p.x, result.x, EPSILON);
+ assertEquals(p.y, result.y, EPSILON);
+ assertEquals(p.z, result.z, EPSILON);
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.octree;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+
+/**
+ * Cell-pool behavior of {@link OctreeVolume} — most notably the
+ * exhaustion path, which used to hang in an infinite rescan loop.
+ */
+public class OctreeVolumeTest {
+
+ /**
+ * Allocating more cells than the pool holds must fail loudly
+ * ({@link IllegalStateException}), not hang. The 5s timeout fails the
+ * test on the pre-fix implementation (infinite loop).
+ */
+ @Test(timeout = 5000)
+ public void cellPoolExhaustionFailsLoudly() {
+ final OctreeVolume volume = new OctreeVolume();
+ volume.initWorld(8, 64); // tiny pool: 8 cells
+
+ try {
+ // master cell + up to 8 more allocations — must throw by then
+ for (int i = 0; i < 16; i++)
+ volume.makeNewCell(0x808080, 0);
+ fail("expected IllegalStateException on pool exhaustion");
+ } catch (final IllegalStateException e) {
+ assertTrue("message should name the pool capacity: " + e.getMessage(),
+ e.getMessage().contains("8"));
+ }
+ }
+
+ /** Sanity: within capacity, allocation keeps working and cells are solid. */
+ @Test(timeout = 5000)
+ public void allocationWithinCapacityWorks() {
+ final OctreeVolume volume = new OctreeVolume();
+ volume.initWorld(16, 64);
+
+ final int pointer = volume.makeNewCell(0x123456, 7);
+ assertTrue(pointer >= 0);
+ assertTrue(volume.isCellSolid(pointer));
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.RenderingContext;
+import eu.svjatoslav.aukio.e3d.gui.ViewPanel;
+import eu.svjatoslav.aukio.e3d.math.Transform;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.AbstractCoordinateShape;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.line.LineAppearance;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon.SolidPolygon;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base.AbstractCompositeShape;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.solid.SolidPolygonCube;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.solid.SolidPolygonSphere;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.wireframe.WireframeCube;
+import org.junit.After;
+import org.junit.Test;
+
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+
+import eu.svjatoslav.aukio.e3d.math.TransformStack;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * Verifies that the parallel transform+sort pipeline produces exactly the
+ * same render queue as the serial pipeline: same shapes, same order, same
+ * culling decisions.
+ */
+public class ParallelTransformTest {
+
+ private static final int W = 1280, H = 720;
+ private static final double EPSILON = 1e-9;
+
+ private ExecutorService executor;
+
+ @After
+ public void tearDown() {
+ if (executor != null) {
+ executor.shutdownNow();
+ }
+ }
+
+ private ShapeCollection buildScene(final ViewPanel panel) {
+ final ShapeCollection scene = panel.getRootShapeCollection();
+ panel.getCamera().getTransform().setTranslation(new Point3D(0, 0, -600));
+
+ // Top-level spheres: each expands to hundreds of triangles internally
+ for (int i = 0; i < 40; i++) {
+ scene.addShape(new SolidPolygonSphere(
+ new Point3D((i % 8 - 4) * 60, (i / 8 - 2) * 60, 400),
+ 25, 12, Color.GREEN));
+ }
+
+ // Many cheap wireframe cubes -> enough top-level items to fork on
+ final LineAppearance appearance = new LineAppearance(2.0, Color.CYAN);
+ for (int i = 0; i < 200; i++) {
+ scene.addShape(new WireframeCube(
+ new Point3D((i % 20 - 10) * 40, (i / 20 - 5) * 40, 700),
+ 15, appearance));
+ }
+
+ // Nested composite with its own transform -> transform stacking
+ final AbstractCompositeShape nested = new AbstractCompositeShape(new Point3D(50, -50, 500));
+ nested.setTransform(Transform.fromAngles(50, -50, 500, 0.3, 0.2, 0.1));
+ nested.addShape(new SolidPolygonCube(new Point3D(0, 0, 0), 30, Color.RED));
+ nested.addShape(new SolidPolygonSphere(new Point3D(80, 0, 40), 20, 10, Color.BLUE));
+ scene.addShape(nested);
+
+ // Composite entirely behind the camera -> frustum culling inside workers
+ final AbstractCompositeShape offscreen = new AbstractCompositeShape(new Point3D(0, 0, -5000));
+ offscreen.addShape(new SolidPolygonCube(new Point3D(0, 0, 0), 30, Color.RED));
+ scene.addShape(offscreen);
+
+ // Quad -> N-gon triangulation path
+ scene.addShape(SolidPolygon.quad(
+ new Point3D(-100, -100, 300), new Point3D(100, -100, 300),
+ new Point3D(100, 100, 300), new Point3D(-100, 100, 300),
+ Color.WHITE));
+
+ return scene;
+ }
+
+ private int[] snapshotIds(final ShapeCollection scene) {
+ final List<AbstractCoordinateShape> queue = scene.getQueuedShapes();
+ final int[] ids = new int[queue.size()];
+ for (int i = 0; i < ids.length; i++) {
+ ids[i] = queue.get(i).shapeId;
+ }
+ return ids;
+ }
+
+ private double[] snapshotZs(final ShapeCollection scene) {
+ final List<AbstractCoordinateShape> queue = scene.getQueuedShapes();
+ final double[] zs = new double[queue.size()];
+ for (int i = 0; i < zs.length; i++) {
+ zs[i] = queue.get(i).getZ(0);
+ }
+ return zs;
+ }
+
+ @Test
+ public void parallelTransformMatchesSerialPipeline() {
+ System.setProperty("java.awt.headless", "true");
+ final ViewPanel panel = new ViewPanel();
+ final ShapeCollection scene = buildScene(panel);
+
+ // Serial run: no executor -> serial fallback path
+ final RenderingContext serialCtx = new RenderingContext(W, H, 1);
+ serialCtx.prepareForNewFrameRendering();
+ scene.transformShapes(panel.getCamera(), serialCtx);
+ scene.sortShapes();
+ final int[] serialIds = snapshotIds(scene);
+ final double[] serialZs = snapshotZs(scene);
+ final int serialTotal = serialCtx.cullingStatistics.totalComposites.get();
+ final int serialCulled = serialCtx.cullingStatistics.culledComposites.get();
+
+ // Parallel run: executor set -> forked traversal
+ executor = Executors.newFixedThreadPool(8);
+ final RenderingContext parallelCtx = new RenderingContext(W, H, 1);
+ parallelCtx.transformExecutor = executor;
+ parallelCtx.prepareForNewFrameRendering();
+ parallelCtx.prepareForNewFrameRendering(); // distinct frameNumber -> full re-transform
+ scene.transformShapes(panel.getCamera(), parallelCtx);
+ scene.sortShapes();
+ final int[] parallelIds = snapshotIds(scene);
+ final double[] parallelZs = snapshotZs(scene);
+
+ // Same render queue, same order (sort is deterministic: Z then shapeId)
+ assertEquals("queued shape count", serialIds.length, parallelIds.length);
+ assertTrue("scene must be big enough to exercise parallel paths",
+ serialIds.length > 8192);
+ for (int i = 0; i < serialIds.length; i++) {
+ assertEquals("shapeId at position " + i, serialIds[i], parallelIds[i]);
+ assertEquals("Z at position " + i, serialZs[i], parallelZs[i], EPSILON);
+ }
+
+ // Same culling decisions (and thread-safe counters)
+ assertEquals(serialTotal, parallelCtx.cullingStatistics.totalComposites.get());
+ assertEquals(serialCulled, parallelCtx.cullingStatistics.culledComposites.get());
+ assertTrue("offscreen composite must be culled", serialCulled >= 1);
+
+ // Sortedness property: Z descending, shapeId ascending tiebreak.
+ // Tiebreak comparison must be exact, matching the comparator's
+ // double semantics — nearly-equal Z values are NOT a tie.
+ for (int i = 1; i < parallelIds.length; i++) {
+ assertTrue("Z order at " + i, parallelZs[i - 1] >= parallelZs[i]);
+ if (parallelZs[i - 1] == parallelZs[i]) {
+ assertTrue("shapeId tiebreak at " + i, parallelIds[i - 1] < parallelIds[i]);
+ }
+ }
+ }
+
+ @Test
+ public void nestedHeavyCompositeForksInternally() {
+ System.setProperty("java.awt.headless", "true");
+ final ViewPanel panel = new ViewPanel();
+ final ShapeCollection scene = panel.getRootShapeCollection();
+ panel.getCamera().getTransform().setTranslation(new Point3D(0, 0, -600));
+
+ // Few root children: root stays below the parallel threshold and
+ // transforms serially, so any fork must come from the nested level
+ scene.addShape(new SolidPolygonSphere(new Point3D(-200, 0, 400), 25, 10, Color.GREEN));
+ scene.addShape(new SolidPolygonSphere(new Point3D(200, 0, 400), 25, 10, Color.RED));
+
+ // One outsized nested composite, well above the fork threshold
+ final AbstractCompositeShape giant = new AbstractCompositeShape(new Point3D(0, 0, 300));
+ final LineAppearance appearance = new LineAppearance(2.0, Color.CYAN);
+ for (int i = 0; i < 200; i++) {
+ giant.addShape(new WireframeCube(
+ new Point3D((i % 20 - 10) * 40, (i / 20 - 5) * 40, 200),
+ 15, appearance));
+ }
+ scene.addShape(giant);
+
+ // Serial run
+ final RenderingContext serialCtx = new RenderingContext(W, H, 1);
+ serialCtx.prepareForNewFrameRendering();
+ scene.transformShapes(panel.getCamera(), serialCtx);
+ scene.sortShapes();
+ final int[] serialIds = snapshotIds(scene);
+ final double[] serialZs = snapshotZs(scene);
+
+ // Parallel run
+ executor = Executors.newFixedThreadPool(8);
+ final RenderingContext parallelCtx = new RenderingContext(W, H, 1);
+ parallelCtx.transformExecutor = executor;
+ parallelCtx.prepareForNewFrameRendering();
+ parallelCtx.prepareForNewFrameRendering();
+ scene.transformShapes(panel.getCamera(), parallelCtx);
+ scene.sortShapes();
+ final int[] parallelIds = snapshotIds(scene);
+ final double[] parallelZs = snapshotZs(scene);
+
+ // The nested composite must have forked: root has only 3 children
+ // (below the threshold), so all chunk tasks are nested-level
+ assertTrue("nested composite must fork its own children",
+ parallelCtx.lastTransformTaskCount >= 2);
+
+ // Identical render queue
+ assertEquals("queued shape count", serialIds.length, parallelIds.length);
+ assertTrue("scene must be big enough to exercise the fork",
+ serialIds.length > 1000);
+ for (int i = 0; i < serialIds.length; i++) {
+ assertEquals("shapeId at position " + i, serialIds[i], parallelIds[i]);
+ assertEquals("Z at position " + i, serialZs[i], parallelZs[i], EPSILON);
+ }
+ }
+
+ @Test
+ public void renderListRebuildDuringInFlightChunkTasksUsesSnapshottedRenderList() throws Exception {
+ System.setProperty("java.awt.headless", "true");
+
+ // One composite with many children: 4 permanent + 4096 in a group
+ // that will be hidden mid-flight to force a render-list rebuild that
+ // REASSIGNS cachedRenderList to a much smaller list.
+ final AbstractCompositeShape composite =
+ new AbstractCompositeShape(new Point3D(0, 0, 400));
+ composite.setRootComposite(true); // skip frustum culling entirely
+ for (int i = 0; i < 4; i++) {
+ composite.addShape(SolidPolygon.triangle(
+ new Point3D(i * 10, 0, 0), new Point3D(i * 10 + 5, 0, 0),
+ new Point3D(i * 10, 5, 0), Color.GREEN), "keep");
+ }
+ for (int i = 0; i < 4096; i++) {
+ composite.addShape(SolidPolygon.triangle(
+ new Point3D(i % 64, i / 64, 0), new Point3D(i % 64 + 1, i / 64, 0),
+ new Point3D(i % 64, i / 64 + 1, 0), Color.RED), "bulk");
+ }
+
+ executor = Executors.newFixedThreadPool(4);
+
+ // Occupy every pool thread: the chunk tasks submitted below queue
+ // up but cannot start, reproducing the pipeline state where the
+ // NEXT pass's tree walk begins while this pass's chunks are
+ // still pending (the drain runs in the async continuation).
+ final CountDownLatch blockersStarted = new CountDownLatch(4);
+ final CountDownLatch releaseBlockers = new CountDownLatch(1);
+ for (int i = 0; i < 4; i++) {
+ executor.submit(() -> {
+ blockersStarted.countDown();
+ try {
+ releaseBlockers.await(30, TimeUnit.SECONDS);
+ } catch (final InterruptedException e) {
+ Thread.currentThread().interrupt();
+ }
+ });
+ }
+ assertTrue("pool blockers must be running",
+ blockersStarted.await(30, TimeUnit.SECONDS));
+
+ // Pass P: forks chunk tasks against the 4100-entry render list.
+ final ParallelTransformCoordinator coordinator =
+ new ParallelTransformCoordinator(executor);
+ final RenderingContext passContext = new RenderingContext(W, H, 1);
+ passContext.prepareForNewFrameRendering();
+ passContext.transformCoordinator = coordinator;
+ final RenderAggregator aggregator = new RenderAggregator();
+ composite.transform(new TransformStack(), aggregator, passContext);
+ assertTrue("composite must have forked chunk tasks",
+ coordinator.getSubmittedTaskCount() >= 2);
+
+ // Pass P+1's tree walk arrives while P's chunk tasks are still
+ // queued: hiding "bulk" forces a render-list rebuild that reassigns
+ // cachedRenderList to a 4-entry list. (No coordinator on this
+ // context -> serial path, itself immune to the race.)
+ composite.hideGroup("bulk");
+ final RenderingContext nextContext = new RenderingContext(W, H, 1);
+ nextContext.prepareForNewFrameRendering();
+ composite.transform(new TransformStack(), new RenderAggregator(), nextContext);
+
+ // Now P's chunk tasks run. They must iterate the SAME list
+ // instance their chunk ranges were computed against — re-reading
+ // the reassigned field threw IndexOutOfBoundsException (observed
+ // in production: "Index 258 out of bounds for length 24").
+ releaseBlockers.countDown();
+ coordinator.drainAndMergeInto(aggregator);
+ }
+}
--- /dev/null
+package eu.svjatoslav.aukio.e3d.renderer.raster;
+
+import org.junit.Test;
+
+import java.util.Random;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * Verifies the radix sort core: key mapping reproduces the Z-comparator's
+ * ordering semantics, and the pair sort is sorted and stable.
+ */
+public class RadixLongSortTest {
+
+ /** The comparator's Z comparison: -1/0/+1 with NaN treated as "equal". */
+ private static int compareZ(final double z1, final double z2) {
+ if (z1 < z2)
+ return 1; // painter order: larger z first
+ if (z1 > z2)
+ return -1;
+ return 0;
+ }
+
+ @Test
+ public void keyOrderMatchesComparator() {
+ final double[] specials = {
+ 0.0d, -0.0d, 1.0d, -1.0d, 5e-3d, 96.0d, 1e6d,
+ Double.MIN_VALUE, -Double.MIN_VALUE,
+ Double.MAX_VALUE, -Double.MAX_VALUE,
+ Double.POSITIVE_INFINITY, Double.NEGATIVE_INFINITY,
+ 123456.789d, -123456.789d
+ };
+ final Random random = new Random(42);
+ final double[] values = new double[specials.length + 500];
+ System.arraycopy(specials, 0, values, 0, specials.length);
+ for (int i = specials.length; i < values.length; i++)
+ values[i] = (random.nextDouble() - 0.5) * 2e6;
+ for (final double z1 : values)
+ for (final double z2 : values) {
+ final int expected = compareZ(z1, z2);
+ final int actual = Long.compareUnsigned(
+ RadixLongSort.zSortKey(z1), RadixLongSort.zSortKey(z2));
+ assertTrue("z1=" + z1 + " z2=" + z2 + " expected sign "
+ + expected + " got " + actual,
+ Integer.signum(expected) == Integer.signum(actual));
+ }
+ }
+
+ @Test
+ public void minusZeroAndPlusZeroShareOneKey() {
+ assertEquals(RadixLongSort.zSortKey(0.0d),
+ RadixLongSort.zSortKey(-0.0d));
+ }
+
+ @Test
+ public void sortPairsIsSortedAndStable() {
+ final Random random = new Random(7);
+ for (final int n : new int[]{0, 1, 2, 100, 10000}) {
+ final long[] keys = new long[Math.max(n, 1)];
+ final long[] keysTmp = new long[Math.max(n, 1)];
+ final int[] idx = new int[Math.max(n, 1)];
+ final int[] idxTmp = new int[Math.max(n, 1)];
+ // Duplicate-heavy keys exercise stability
+ for (int i = 0; i < n; i++) {
+ keys[i] = random.nextInt(50);
+ idx[i] = i;
+ }
+ RadixLongSort.sortPairs(keys, idx, n, keysTmp, idxTmp);
+ for (int i = 1; i < n; i++) {
+ assertTrue("sorted at " + i,
+ Long.compareUnsigned(keys[i - 1], keys[i]) <= 0);
+ if (keys[i - 1] == keys[i])
+ assertTrue("stable at " + i, idx[i - 1] < idx[i]);
+ }
+ }
+ }
+
+ @Test
+ public void sortPairsHandlesFullUnsignedRange() {
+ final Random random = new Random(99);
+ final int n = 5000;
+ final long[] keys = new long[n];
+ final long[] keysTmp = new long[n];
+ final int[] idx = new int[n];
+ final int[] idxTmp = new int[n];
+ for (int i = 0; i < n; i++) {
+ keys[i] = random.nextLong(); // full range incl. "negative"
+ idx[i] = i;
+ }
+ RadixLongSort.sortPairs(keys, idx, n, keysTmp, idxTmp);
+ for (int i = 1; i < n; i++)
+ assertTrue(Long.compareUnsigned(keys[i - 1], keys[i]) <= 0);
+ }
+
+ /**
+ * The parallel pair sort must produce output BIT-IDENTICAL to the
+ * serial one for any chunk count (stability makes the partitioning
+ * invisible) — golden-image determinism depends on it.
+ */
+ @Test
+ public void parallelMatchesSerialBitExactly() throws Exception {
+ final java.util.concurrent.ExecutorService executor =
+ java.util.concurrent.Executors.newFixedThreadPool(4);
+ try {
+ final Random random = new Random(1234);
+ for (final int n : new int[]{0, 1, 7, 1000, 65536, 250000}) {
+ for (final int threads : new int[]{1, 2, 3, 8}) {
+ final long[] keys = new long[Math.max(n, 1)];
+ final int[] idx = new int[Math.max(n, 1)];
+ // duplicate-heavy + full-range mix exercises both
+ // stability and unsigned digit handling
+ for (int i = 0; i < n; i++) {
+ keys[i] = (i & 1) == 0
+ ? random.nextInt(37)
+ : random.nextLong();
+ idx[i] = i;
+ }
+ final long[] serialKeys = keys.clone();
+ final int[] serialIdx = idx.clone();
+ RadixLongSort.sortPairs(serialKeys, serialIdx, n,
+ new long[Math.max(n, 1)], new int[Math.max(n, 1)]);
+
+ final long[] parKeys = keys.clone();
+ final int[] parIdx = idx.clone();
+ RadixLongSort.sortPairsParallel(parKeys, parIdx, n,
+ new long[Math.max(n, 1)], new int[Math.max(n, 1)],
+ new int[Math.max(threads, 1) * 512],
+ executor, threads);
+
+ org.junit.Assert.assertArrayEquals(
+ "keys n=" + n + " threads=" + threads,
+ serialKeys, parKeys);
+ org.junit.Assert.assertArrayEquals(
+ "idx n=" + n + " threads=" + threads,
+ serialIdx, parIdx);
+ }
+ }
+ } finally {
+ executor.shutdownNow();
+ }
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point2D;
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.RenderingContext;
+import eu.svjatoslav.aukio.e3d.renderer.raster.SegmentRenderingContext;
+import eu.svjatoslav.aukio.e3d.gui.ViewPanel;
+import eu.svjatoslav.aukio.e3d.math.Transform;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Vertex;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.AbstractCoordinateShape;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.GlowingPoint;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.line.Line;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.line.LineAppearance;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon.SolidPolygon;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.texturedpolygon.TexturedTriangle;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.solid.SolidPolygonCube;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.solid.SolidPolygonSphere;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.textcanvas.TextCanvas;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.wireframe.WireframeCube;
+import eu.svjatoslav.aukio.e3d.renderer.raster.texture.Texture;
+import eu.svjatoslav.aukio.e3d.renderer.raster.texture.TextureGenerator;
+import org.junit.After;
+import org.junit.Test;
+
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+
+/**
+ * Verifies that paint tile binning produces pixel-identical output to
+ * painting the full sorted queue in every tile: binning must only skip
+ * shapes that cannot touch a tile's rectangle, never shapes that can.
+ *
+ * <p>The scene deliberately includes shapes whose paint output extends
+ * past their vertex bounds on both axes (thick lines, glowing point
+ * billboards, text glyphs) to exercise the per-shape X/Y margins.</p>
+ */
+public class SegmentBinningTest {
+
+ private static final int W = 1280, H = 720;
+ private static final int TILES_X = 4, TILES_Y = 3;
+ private static final int TILE_COUNT = TILES_X * TILES_Y;
+
+ private ExecutorService executor;
+
+ @After
+ public void tearDown() {
+ if (executor != null) {
+ executor.shutdownNow();
+ }
+ }
+
+ private ShapeCollection buildScene(final ViewPanel panel, final int sphereCount) {
+ final ShapeCollection scene = panel.getRootShapeCollection();
+ panel.getCamera().getTransform().setTranslation(new Point3D(0, 0, -600));
+
+ // Solid spheres spread across the whole viewport
+ for (int i = 0; i < sphereCount; i++) {
+ scene.addShape(new SolidPolygonSphere(
+ new Point3D((i % 6 - 3) * 90, (i / 6 - 2) * 80, 400),
+ 30, 10, Color.GREEN));
+ }
+
+ // Wireframe cubes (thin lines)
+ final LineAppearance appearance = new LineAppearance(2.0, Color.CYAN);
+ for (int i = 0; i < 30; i++) {
+ scene.addShape(new WireframeCube(
+ new Point3D((i % 10 - 5) * 70, (i / 10 - 1) * 90, 700),
+ 20, appearance));
+ }
+
+ // Thick lines crossing tile boundaries on both axes
+ scene.addShape(new Line(
+ new Point3D(-300, -200, 300), new Point3D(300, 250, 300),
+ Color.YELLOW, 8.0));
+ scene.addShape(new Line(
+ new Point3D(-250, 250, 350), new Point3D(250, -250, 350),
+ Color.RED, 6.0));
+ // Vertical thick line: X margin matters, Y range covers all rows
+ scene.addShape(new Line(
+ new Point3D(0, -300, 300), new Point3D(0, 300, 300),
+ Color.GREEN, 8.0));
+
+ // Glowing points (billboards): quad extends far beyond the vertex
+ for (int i = 0; i < 8; i++) {
+ scene.addShape(new GlowingPoint(
+ new Point3D((i % 4 - 2) * 120, (i / 4 - 0.5) * 150, 250),
+ 40, Color.WHITE));
+ }
+
+ // Text canvas: glyph extends beyond the character cell vertices
+ final TextCanvas text = new TextCanvas(
+ new Transform(new Point3D(-100, -50, 500)),
+ "Binning!", Color.WHITE, Color.BLUE);
+ scene.addShape(text);
+
+ // A quad and a cube for variety
+ scene.addShape(SolidPolygon.quad(
+ new Point3D(-120, -120, 300), new Point3D(120, -120, 300),
+ new Point3D(120, 120, 300), new Point3D(-120, 120, 300),
+ Color.WHITE));
+ scene.addShape(new SolidPolygonCube(new Point3D(200, 100, 350), 40, Color.RED));
+
+ // Large textured triangles spanning multiple tile rows. Big
+ // on screen — exercises textured-triangle binning, whose bounds
+ // formerly stayed (0,0) and binned it into the topmost segment only.
+ final Texture texture = TextureGenerator.solidWithBorder(
+ 32, Color.YELLOW, Color.WHITE, 2, 1);
+ scene.addShape(new TexturedTriangle(
+ new Vertex(new Point3D(-400, -300, 250), new Point2D(0, 0)),
+ new Vertex(new Point3D(400, -100, 250), new Point2D(1, 0)),
+ new Vertex(new Point3D(0, 400, 250), new Point2D(0.5, 1)),
+ texture));
+ scene.addShape(new TexturedTriangle(
+ new Vertex(new Point3D(-500, 100, 300), new Point2D(0, 0)),
+ new Vertex(new Point3D(-100, -50, 300), new Point2D(1, 0)),
+ new Vertex(new Point3D(-300, 500, 300), new Point2D(0.5, 1)),
+ texture));
+
+ return scene;
+ }
+
+ /**
+ * Paints the current frame's sorted queue into a fresh context using
+ * one full-range pass (no binning possible).
+ */
+ private RenderingContext paintReference(final ShapeCollection scene) {
+ final RenderingContext reference = new RenderingContext(W, H, TILES_X, TILES_Y, 1);
+ scene.paintShapes(reference);
+ return reference;
+ }
+
+ /**
+ * Paints the current frame's sorted queue tile-by-tile into a fresh
+ * context, using whatever bins are currently active.
+ */
+ private RenderingContext paintTiled(final ShapeCollection scene) {
+ final RenderingContext tiled = new RenderingContext(W, H, TILES_X, TILES_Y, 1);
+ final int tileW = W / TILES_X;
+ final int tileH = H / TILES_Y;
+ for (int ty = 0; ty < TILES_Y; ty++) {
+ final int minY = ty * tileH;
+ final int maxY = (ty == TILES_Y - 1) ? H : (ty + 1) * tileH;
+ for (int tx = 0; tx < TILES_X; tx++) {
+ final int minX = tx * tileW;
+ final int maxX = (tx == TILES_X - 1) ? W : (tx + 1) * tileW;
+ final SegmentRenderingContext tileContext = new SegmentRenderingContext(
+ tiled, minY, maxY, ty * TILES_X + tx);
+ tileContext.renderMinX = minX;
+ tileContext.renderMaxX = maxX;
+ scene.paintShapes(tileContext);
+ }
+ }
+ return tiled;
+ }
+
+ private void assertPixelsEqual(final RenderingContext expected,
+ final RenderingContext actual) {
+ final int tileW = W / TILES_X;
+ final int tileH = H / TILES_Y;
+ for (int i = 0; i < expected.pixels.length; i++) {
+ if (expected.pixels[i] != actual.pixels[i]) {
+ final int x = i % W;
+ final int y = i / W;
+ fail("pixel mismatch at (" + x + "," + y + ") tile ("
+ + Math.min(x / tileW, TILES_X - 1) + ","
+ + Math.min(y / tileH, TILES_Y - 1) + ")"
+ + ": expected=" + Integer.toHexString(expected.pixels[i])
+ + " actual=" + Integer.toHexString(actual.pixels[i]));
+ }
+ }
+ }
+
+ private void transformAndSort(final ViewPanel panel, final ShapeCollection scene,
+ final RenderingContext context) {
+ context.prepareForNewFrameRendering();
+ scene.transformShapes(panel.getCamera(), context);
+ scene.sortShapes();
+ }
+
+ @Test
+ public void serialBinningMatchesFullQueuePaint() {
+ System.setProperty("java.awt.headless", "true");
+ final ViewPanel panel = new ViewPanel();
+ final ShapeCollection scene = buildScene(panel, 24);
+
+ // Transform and sort once; paint is read-only on shape state,
+ // so the same frame can be painted into multiple buffers.
+ transformAndSort(panel, scene, new RenderingContext(W, H, TILES_X, TILES_Y, 1));
+
+ // The scene must contain textured triangles spanning multiple
+ // tiles, otherwise the binning-bounds regression (bounds left at
+ // 0,0 -> binned into the topmost segment only) is not covered
+ boolean anyTextured = false;
+ for (final AbstractCoordinateShape shape : scene.getQueuedShapes()) {
+ if (shape instanceof TexturedTriangle) {
+ anyTextured = true;
+ break;
+ }
+ }
+ assertTrue("scene must contain textured triangles",
+ anyTextured);
+
+ final RenderingContext reference = paintReference(scene);
+
+ // Serial binning (null executor)
+ scene.binShapesForTiles(TILES_X, TILES_Y, 0, W, H, null);
+ final int[] binSizes = scene.getBinSizes();
+ assertNotNull("bins must be built", binSizes);
+ assertEquals(TILE_COUNT, binSizes.length);
+
+ // Binning must reduce total per-tile iterations versus every
+ // tile iterating the whole queue
+ final int queueSize = scene.getQueuedShapeCount();
+ int totalBinEntries = 0;
+ for (final int size : binSizes) {
+ totalBinEntries += size;
+ }
+ assertTrue("binning must reduce total paint iterations ("
+ + totalBinEntries + " >= " + (TILE_COUNT * queueSize) + ")",
+ totalBinEntries < TILE_COUNT * queueSize);
+
+ assertPixelsEqual(reference, paintTiled(scene));
+ }
+
+ @Test
+ public void parallelBinningMatchesSerialAndFullQueuePaint() {
+ System.setProperty("java.awt.headless", "true");
+ final ViewPanel panel = new ViewPanel();
+ // Enough shapes to exceed the parallel binning threshold (8192)
+ final ShapeCollection scene = buildScene(panel, 80);
+
+ transformAndSort(panel, scene, new RenderingContext(W, H, TILES_X, TILES_Y, 1));
+ final int queueSize = scene.getQueuedShapeCount();
+ assertTrue("scene must exceed the parallel binning threshold",
+ queueSize > 8192);
+ final RenderingContext reference = paintReference(scene);
+
+ // Serial bins -> tiled paint A
+ scene.binShapesForTiles(TILES_X, TILES_Y, 0, W, H, null);
+ final int[] serialBinSizes = scene.getBinSizes();
+ final RenderingContext serialTiled = paintTiled(scene);
+
+ // Parallel bins -> tiled paint B
+ executor = Executors.newFixedThreadPool(8);
+ scene.binShapesForTiles(TILES_X, TILES_Y, 0, W, H, executor);
+ final int[] parallelBinSizes = scene.getBinSizes();
+ final RenderingContext parallelTiled = paintTiled(scene);
+
+ // Same bin layout, same pixels
+ org.junit.Assert.assertArrayEquals(serialBinSizes, parallelBinSizes);
+ assertPixelsEqual(reference, serialTiled);
+ assertPixelsEqual(reference, parallelTiled);
+ }
+
+ @Test
+ public void fullRangeContextFallsBackToFullQueue() {
+ System.setProperty("java.awt.headless", "true");
+ final ViewPanel panel = new ViewPanel();
+ final ShapeCollection scene = buildScene(panel, 24);
+
+ final RenderingContext context = new RenderingContext(W, H, TILES_X, TILES_Y, 1);
+ transformAndSort(panel, scene, context);
+ scene.binShapesForTiles(TILES_X, TILES_Y, 0, W, H, null);
+
+ // A full-range context matches no single tile: must paint the full
+ // queue (verified by it producing non-background pixels at all)
+ scene.paintShapes(context);
+ boolean anyPainted = false;
+ for (final int pixel : context.pixels) {
+ if (pixel != 0) {
+ anyPainted = true;
+ break;
+ }
+ }
+ assertTrue("full-range paint must render shapes", anyPainted);
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.texturedpolygon;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point2D;
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.RenderingContext;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Vertex;
+import eu.svjatoslav.aukio.e3d.renderer.raster.texture.TextureBitmap;
+import org.junit.Test;
+
+import java.lang.reflect.Method;
+import java.util.Random;
+
+import static org.junit.Assert.assertEquals;
+
+/**
+ * Pixel-exactness proof for the optimized textured scanline renderer:
+ * the one-multiply alpha blend and the clamp-free fast path must produce
+ * output identical to the legacy implementation, bit for bit.
+ */
+public class TexturedTriangleBlendTest {
+
+ /** Legacy two-multiply blend, the original semantics. */
+ private static int legacyBlendChannel(final int src, final int dest, final int alpha) {
+ return ((dest * (255 - alpha)) + (src * alpha)) >> 8;
+ }
+
+ /** Optimized one-multiply blend, must equal legacy for every input. */
+ private static int fastBlendChannel(final int src, final int dest, final int alpha) {
+ return dest + ((alpha * (src - dest) - dest) >> 8);
+ }
+
+ @Test
+ public void oneMultiplyBlendMatchesLegacyBlend() {
+ final int[] channelValues = {0, 1, 2, 63, 127, 128, 200, 254, 255};
+ for (int alpha = 0; alpha <= 255; alpha++) {
+ for (final int src : channelValues) {
+ for (final int dest : channelValues) {
+ assertEquals("src=" + src + " dest=" + dest + " alpha=" + alpha,
+ legacyBlendChannel(src, dest, alpha),
+ fastBlendChannel(src, dest, alpha));
+ }
+ }
+ }
+ final Random random = new Random(42);
+ for (int i = 0; i < 1_000_000; i++) {
+ final int src = random.nextInt(256);
+ final int dest = random.nextInt(256);
+ final int alpha = random.nextInt(256);
+ assertEquals("src=" + src + " dest=" + dest + " alpha=" + alpha,
+ legacyBlendChannel(src, dest, alpha),
+ fastBlendChannel(src, dest, alpha));
+ }
+ }
+
+ /**
+ * Legacy scanline implementation (pre-optimization), used as the
+ * oracle: the optimized drawHorizontalLineZ must match it exactly.
+ */
+ private static void legacyDrawHorizontalLine(
+ final PolygonBorderInterpolator line1, final PolygonBorderInterpolator line2,
+ final int y, final int[] renderBufferPixels, final int width,
+ final int renderMinX, final int renderMaxX,
+ final TextureBitmap textureBitmap) {
+ line1.setCurrentY(y);
+ line2.setCurrentY(y);
+
+ int x1 = line1.getX();
+ int x2 = line2.getX();
+
+ final double tx2, ty2;
+ final double tx1, ty1;
+
+ if (x1 <= x2) {
+ tx1 = line1.getTX() * textureBitmap.multiplicationFactor;
+ ty1 = line1.getTY() * textureBitmap.multiplicationFactor;
+ tx2 = line2.getTX() * textureBitmap.multiplicationFactor;
+ ty2 = line2.getTY() * textureBitmap.multiplicationFactor;
+ } else {
+ final int tmp = x1;
+ x1 = x2;
+ x2 = tmp;
+ tx1 = line2.getTX() * textureBitmap.multiplicationFactor;
+ ty1 = line2.getTY() * textureBitmap.multiplicationFactor;
+ tx2 = line1.getTX() * textureBitmap.multiplicationFactor;
+ ty2 = line1.getTY() * textureBitmap.multiplicationFactor;
+ }
+
+ final double realWidth = x2 - x1;
+ final double realX1 = x1;
+
+ if (x1 < renderMinX)
+ x1 = renderMinX;
+ if (x2 >= renderMaxX)
+ x2 = renderMaxX;
+
+ int renderBufferOffset = (y * width) + x1;
+
+ final double twidth = tx2 - tx1;
+ final double theight = ty2 - ty1;
+
+ final double txStep = twidth / realWidth;
+ final double tyStep = theight / realWidth;
+
+ double tx = tx1 + txStep * (x1 - realX1);
+ double ty = ty1 + tyStep * (x1 - realX1);
+
+ final int[] texPixels = textureBitmap.pixels;
+ final int texW = textureBitmap.width;
+ final int texH = textureBitmap.height;
+ final int texWMinus1 = texW - 1;
+ final int texHMinus1 = texH - 1;
+
+ for (int x = x1; x < x2; x++) {
+ int itx = (int) tx;
+ int ity = (int) ty;
+
+ if (itx < 0) itx = 0;
+ else if (itx > texWMinus1) itx = texWMinus1;
+
+ if (ity < 0) ity = 0;
+ else if (ity > texHMinus1) ity = texHMinus1;
+
+ final int srcPixel = texPixels[ity * texW + itx];
+ final int srcAlpha = (srcPixel >> 24) & 0xff;
+
+ if (srcAlpha != 0) {
+ if (srcAlpha == 255) {
+ renderBufferPixels[renderBufferOffset] = srcPixel;
+ } else {
+ final int destPixel = renderBufferPixels[renderBufferOffset];
+ final int destR = (destPixel >> 16) & 0xff;
+ final int destG = (destPixel >> 8) & 0xff;
+ final int destB = destPixel & 0xff;
+
+ final int r = legacyBlendChannel((srcPixel >> 16) & 0xff, destR, srcAlpha);
+ final int g = legacyBlendChannel((srcPixel >> 8) & 0xff, destG, srcAlpha);
+ final int b = legacyBlendChannel(srcPixel & 0xff, destB, srcAlpha);
+
+ renderBufferPixels[renderBufferOffset] = (r << 16) | (g << 8) | b;
+ }
+ }
+
+ tx += txStep;
+ ty += tyStep;
+ renderBufferOffset++;
+ }
+ }
+
+ @Test
+ public void scanlineMatchesLegacyImplementation() throws Exception {
+ final int width = 96;
+ final int height = 8;
+ final Random random = new Random(1337);
+
+ // Texture with a mix of transparent, semi-transparent and opaque pixels
+ final int texW = 16, texH = 16;
+ final int[] texPixels = new int[texW * texH];
+ for (int i = 0; i < texPixels.length; i++) {
+ final int alpha;
+ switch (random.nextInt(4)) {
+ case 0: alpha = 0; break;
+ case 1: alpha = 255; break;
+ default: alpha = 1 + random.nextInt(254);
+ }
+ texPixels[i] = (alpha << 24) | (random.nextInt(256) << 16)
+ | (random.nextInt(256) << 8) | random.nextInt(256);
+ }
+ final TextureBitmap textureBitmap = new TextureBitmap(texW, texH, texPixels, 1.0);
+
+ final TexturedTriangle triangle = new TexturedTriangle(
+ new Vertex(new Point3D(0, 0, 0), new Point2D(0, 0)),
+ new Vertex(new Point3D(1, 0, 0), new Point2D(1, 0)),
+ new Vertex(new Point3D(0, 1, 0), new Point2D(0, 1)), null);
+
+ final Method draw = TexturedTriangle.class.getDeclaredMethod("drawHorizontalLineZ",
+ PolygonBorderInterpolator.class, PolygonBorderInterpolator.class,
+ int.class, RenderingContext.class, TextureBitmap.class);
+ draw.setAccessible(true);
+
+ for (int iteration = 0; iteration < 5000; iteration++) {
+ // Random span endpoints, including out-of-texture and
+ // out-of-render-bounds cases, and reversed X order
+ final double sx1 = random.nextDouble() * width * 1.5 - width * 0.25;
+ final double sx2 = random.nextDouble() * width * 1.5 - width * 0.25;
+ final double u1 = random.nextDouble() * 2.0 - 0.5;
+ final double v1 = random.nextDouble() * 2.0 - 0.5;
+ final double u2 = random.nextDouble() * 2.0 - 0.5;
+ final double v2 = random.nextDouble() * 2.0 - 0.5;
+ final int y = 1 + random.nextInt(height - 2);
+
+ final PolygonBorderInterpolator line1 = new PolygonBorderInterpolator();
+ final PolygonBorderInterpolator line2 = new PolygonBorderInterpolator();
+ line1.setPoints(new Point2D(sx1, y), new Point2D(sx1, y + 1),
+ new Point2D(u1, v1), new Point2D(u1, v1));
+ line2.setPoints(new Point2D(sx2, y), new Point2D(sx2, y + 1),
+ new Point2D(u2, v2), new Point2D(u2, v2));
+
+ final int[] actual = new int[width * height];
+ final int[] expected = new int[width * height];
+ for (int i = 0; i < actual.length; i++) {
+ actual[i] = expected[i] = 0xFF000000 | random.nextInt(0xFFFFFF);
+ }
+
+ final RenderingContext context = new RenderingContext(width, height, 1);
+ System.arraycopy(actual, 0, context.pixels, 0, actual.length);
+ context.renderMinX = 0;
+ context.renderMaxX = width;
+
+ // Fresh interpolators for the oracle (setCurrentY mutates them)
+ final PolygonBorderInterpolator oLine1 = new PolygonBorderInterpolator();
+ final PolygonBorderInterpolator oLine2 = new PolygonBorderInterpolator();
+ oLine1.setPoints(new Point2D(sx1, y), new Point2D(sx1, y + 1),
+ new Point2D(u1, v1), new Point2D(u1, v1));
+ oLine2.setPoints(new Point2D(sx2, y), new Point2D(sx2, y + 1),
+ new Point2D(u2, v2), new Point2D(u2, v2));
+
+ java.util.Arrays.fill(context.depth, Float.NEGATIVE_INFINITY);
+ draw.invoke(triangle, line1, line2, y, context, textureBitmap);
+ legacyDrawHorizontalLine(oLine1, oLine2, y, expected, width,
+ 0, width, textureBitmap);
+
+ for (int i = 0; i < expected.length; i++) {
+ if (expected[i] != context.pixels[i]) {
+ final int px = i % width, py = i / width;
+ throw new AssertionError("iteration " + iteration
+ + " pixel(" + px + "," + py + "): expected "
+ + Integer.toHexString(expected[i]) + " but got "
+ + Integer.toHexString(context.pixels[i])
+ + " [span " + sx1 + ".." + sx2 + " uv ("
+ + u1 + "," + v1 + ")->(" + u2 + "," + v2 + ")]");
+ }
+ }
+ }
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.texturedpolygon;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point2D;
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.RenderingContext;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Vertex;
+import eu.svjatoslav.aukio.e3d.renderer.raster.texture.TextureBitmap;
+import org.junit.Test;
+
+import java.lang.reflect.Method;
+import java.util.Random;
+
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+
+/**
+ * Correctness proof for the Quake-style subdivided perspective scanline
+ * renderer: compared against an exact per-pixel divide oracle that mirrors
+ * the production span walk, texel selection must never deviate by more
+ * than one texel per axis (the ulp-boundary artifact inherent to
+ * truncation, present in the affine path as well).
+ */
+public class TexturedTrianglePerspectiveTest {
+
+ private static final int TEX_W = 64;
+ private static final int TEX_H = 64;
+
+ private static TextureBitmap numberedTexture() {
+ final int[] texPixels = new int[TEX_W * TEX_H];
+ for (int i = 0; i < texPixels.length; i++)
+ texPixels[i] = 0xFF000000 | i;
+ return new TextureBitmap(TEX_W, TEX_H, texPixels, 1.0);
+ }
+
+ /**
+ * Exact oracle: replicates the production span setup (rounded
+ * endpoints, gradients over the unclipped width, clip compensation),
+ * but recovers u/v with a division at EVERY pixel.
+ */
+ private static void exactDrawHorizontalLine(
+ final double su1, final double sv1, final double sw1,
+ final double su2, final double sv2, final double sw2,
+ final int rx1, final int rx2,
+ final int clipMinX, final int clipMaxX,
+ final int y, final int[] renderBufferPixels, final int width,
+ final TextureBitmap textureBitmap) {
+
+ final double realWidth = rx2 - rx1;
+ int x1 = Math.max(rx1, clipMinX);
+ int x2 = Math.min(rx2, clipMaxX);
+ if (x2 - x1 <= 0)
+ return;
+
+ final double dsu = (su2 - su1) / realWidth;
+ final double dsv = (sv2 - sv1) / realWidth;
+ final double dsw = (sw2 - sw1) / realWidth;
+
+ double su = su1 + dsu * (x1 - rx1);
+ double sv = sv1 + dsv * (x1 - rx1);
+ double sw = sw1 + dsw * (x1 - rx1);
+
+ int renderBufferOffset = (y * width) + x1;
+
+ final int[] texPixels = textureBitmap.pixels;
+
+ for (int x = x1; x < x2; x++) {
+ final double invW = 1d / sw;
+ int itx = (int) (su * invW);
+ int ity = (int) (sv * invW);
+
+ if (itx < 0) itx = 0;
+ else if (itx > TEX_W - 1) itx = TEX_W - 1;
+ if (ity < 0) ity = 0;
+ else if (ity > TEX_H - 1) ity = TEX_H - 1;
+
+ renderBufferPixels[renderBufferOffset] = texPixels[ity * TEX_W + itx];
+
+ su += dsu;
+ sv += dsv;
+ sw += dsw;
+ renderBufferOffset++;
+ }
+ }
+
+ @Test
+ public void subdividedPerspectiveStaysWithinOneTexelOfExact() throws Exception {
+ final int width = 256;
+ final int height = 8;
+ final Random random = new Random(2026);
+ final TextureBitmap textureBitmap = numberedTexture();
+
+ final TexturedTriangle triangle = new TexturedTriangle(
+ new Vertex(new Point3D(0, 0, 0), new Point2D(0, 0)),
+ new Vertex(new Point3D(1, 0, 0), new Point2D(1, 0)),
+ new Vertex(new Point3D(0, 1, 0), new Point2D(0, 1)), null);
+
+ final Method draw = TexturedTriangle.class.getDeclaredMethod(
+ "drawHorizontalLinePerspectiveZ",
+ PerspectiveBorderInterpolator.class, PerspectiveBorderInterpolator.class,
+ int.class, RenderingContext.class, TextureBitmap.class);
+ draw.setAccessible(true);
+
+ long totalPixels = 0;
+ long identicalPixels = 0;
+ int maxDeviation = 0;
+
+ for (int iteration = 0; iteration < 3000; iteration++) {
+ // Random steep-perspective span: z varies up to 60x across the
+ // span, texture coords may overshoot the texture (clamp path),
+ // and the span may extend past the render bounds (clip path)
+ final double sx1 = random.nextDouble() * width * 0.5;
+ final double sx2 = sx1 + 4 + random.nextDouble() * (width - 8);
+ final double z1 = 0.5 + random.nextDouble() * 31.5;
+ final double z2 = 0.5 + random.nextDouble() * 31.5;
+ final double u1 = random.nextDouble() * 144 - 16;
+ final double v1 = random.nextDouble() * 144 - 16;
+ final double u2 = random.nextDouble() * 144 - 16;
+ final double v2 = random.nextDouble() * 144 - 16;
+ final int y = 1 + random.nextInt(height - 2);
+
+ final double sw1 = 1d / z1, sw2 = 1d / z2;
+ final double su1 = u1 * sw1, sv1 = v1 * sw1;
+ final double su2 = u2 * sw2, sv2 = v2 * sw2;
+
+ final PerspectiveBorderInterpolator line1 = new PerspectiveBorderInterpolator();
+ final PerspectiveBorderInterpolator line2 = new PerspectiveBorderInterpolator();
+ line1.setPoints(new Point2D(sx1, y), new Point2D(sx1, y + 1), su1, sv1, sw1, su1, sv1, sw1);
+ line2.setPoints(new Point2D(sx2, y), new Point2D(sx2, y + 1), su2, sv2, sw2, su2, sv2, sw2);
+
+ final RenderingContext context = new RenderingContext(width, height, 1);
+ context.renderMinX = 0;
+ context.renderMaxX = width;
+
+ java.util.Arrays.fill(context.depth, Float.NEGATIVE_INFINITY);
+ draw.invoke(triangle, line1, line2, y, context, textureBitmap);
+
+ final int rx1 = (int) Math.round(sx1);
+ final int rx2 = (int) Math.round(sx2);
+ final int[] expected = new int[width * height];
+ exactDrawHorizontalLine(su1, sv1, sw1, su2, sv2, sw2,
+ rx1, rx2, 0, width, y, expected, width, textureBitmap);
+
+ final int cx1 = Math.max(rx1, 0);
+ final int cx2 = Math.min(rx2, width);
+ for (int x = cx1; x < cx2; x++) {
+ final int a = context.pixels[y * width + x] & 0xFFFFFF;
+ final int e = expected[y * width + x] & 0xFFFFFF;
+ totalPixels++;
+ if (a == e) {
+ identicalPixels++;
+ } else {
+ final int deviation = Math.max(
+ Math.abs((a % TEX_W) - (e % TEX_W)),
+ Math.abs((a / TEX_W) - (e / TEX_W)));
+ maxDeviation = Math.max(maxDeviation, deviation);
+ }
+ }
+ }
+
+ final double identicalRatio = (double) identicalPixels / totalPixels;
+ if (maxDeviation > 1) {
+ fail("texel deviation " + maxDeviation + " exceeds 1 (identical="
+ + (identicalRatio * 100) + "% over " + totalPixels + " pixels)");
+ }
+ assertTrue("suspiciously few pixels tested: " + totalPixels, totalPixels > 100000);
+ System.out.println("perspective-16 vs exact: identical=" + (identicalRatio * 100)
+ + "% maxTexelDeviation=" + maxDeviation
+ + " over " + totalPixels + " pixels");
+ }
+
+ @Test
+ public void affineWithinHalfTexelBound() throws Exception {
+ // The paint() shortcut uses affine mapping when
+ // texelSpan * (zRatio-1) < 2. Verify: for random spans satisfying
+ // that bound, the affine renderer stays within one texel of the
+ // exact per-pixel divide oracle.
+ final int width = 320;
+ final int height = 8;
+ final Random random = new Random(77);
+ final TextureBitmap textureBitmap = numberedTexture();
+
+ final TexturedTriangle triangle = new TexturedTriangle(
+ new Vertex(new Point3D(0, 0, 0), new Point2D(0, 0)),
+ new Vertex(new Point3D(1, 0, 0), new Point2D(1, 0)),
+ new Vertex(new Point3D(0, 1, 0), new Point2D(0, 1)), null);
+
+ final Method drawAffine = TexturedTriangle.class.getDeclaredMethod(
+ "drawHorizontalLineZ",
+ PolygonBorderInterpolator.class, PolygonBorderInterpolator.class,
+ int.class, RenderingContext.class, TextureBitmap.class);
+ drawAffine.setAccessible(true);
+
+ long totalPixels = 0;
+ int maxDeviation = 0;
+
+ for (int iteration = 0; iteration < 3000; iteration++) {
+ final double sx1 = random.nextDouble() * width * 0.5;
+ final double spanD = 4 + random.nextDouble() * 296;
+ final double sx2 = Math.min(sx1 + spanD, width * 1.2);
+ final double u1 = random.nextDouble() * 56;
+ final double v1 = random.nextDouble() * 56;
+ final double u2 = random.nextDouble() * 56;
+ final double v2 = random.nextDouble() * 56;
+ // z ratio strictly inside the bound, driven by the TEXEL span
+ final double texelSpan = Math.max(Math.abs(u2 - u1), Math.abs(v2 - v1));
+ final double z1 = 1 + random.nextDouble() * 30;
+ final double r = 1 + random.nextDouble() * (1.9 / Math.max(texelSpan, 0.5));
+ final double z2 = z1 * r;
+ final int y = 1 + random.nextInt(height - 2);
+
+ final PolygonBorderInterpolator line1 = new PolygonBorderInterpolator();
+ final PolygonBorderInterpolator line2 = new PolygonBorderInterpolator();
+ line1.setPoints(new Point2D(sx1, y), new Point2D(sx1, y + 1),
+ new Point2D(u1, v1), new Point2D(u1, v1));
+ line2.setPoints(new Point2D(sx2, y), new Point2D(sx2, y + 1),
+ new Point2D(u2, v2), new Point2D(u2, v2));
+
+ final RenderingContext context = new RenderingContext(width, height, 1);
+ context.renderMinX = 0;
+ context.renderMaxX = width;
+
+ java.util.Arrays.fill(context.depth, Float.NEGATIVE_INFINITY);
+ drawAffine.invoke(triangle, line1, line2, y, context, textureBitmap);
+
+ // Exact oracle over the same span (gradients from z1/z2)
+ final double sw1 = 1d / z1, sw2 = 1d / z2;
+ final int rx1 = (int) Math.round(sx1);
+ final int rx2 = (int) Math.round(sx2);
+ final int[] expected = new int[width * height];
+ exactDrawHorizontalLine(u1 * sw1, v1 * sw1, sw1, u2 * sw2, v2 * sw2, sw2,
+ rx1, rx2, 0, width, y, expected, width, textureBitmap);
+
+ final int cx1 = Math.max(rx1, 0);
+ final int cx2 = Math.min(rx2, width);
+ for (int x = cx1; x < cx2; x++) {
+ final int a = context.pixels[y * width + x] & 0xFFFFFF;
+ final int e = expected[y * width + x] & 0xFFFFFF;
+ totalPixels++;
+ final int deviation = Math.max(
+ Math.abs((a % TEX_W) - (e % TEX_W)),
+ Math.abs((a / TEX_W) - (e / TEX_W)));
+ maxDeviation = Math.max(maxDeviation, deviation);
+ }
+ }
+
+ if (maxDeviation > 1) {
+ fail("affine deviation " + maxDeviation + " exceeds 1 texel within the bound"
+ + " over " + totalPixels + " pixels");
+ }
+ assertTrue("suspiciously few pixels tested: " + totalPixels, totalPixels > 100000);
+ System.out.println("affine within bound: maxTexelDeviation=" + maxDeviation
+ + " over " + totalPixels + " pixels");
+ }
+
+ @Test
+ public void faceOnSpanMatchesAffineWithinOneTexel() throws Exception {
+ // Constant z across the span: perspective correction must reduce
+ // to the affine mapping (u linear in x), modulo the ulp-boundary
+ // truncation artifact.
+ final int width = 200;
+ final int height = 4;
+ final TextureBitmap textureBitmap = numberedTexture();
+
+ final TexturedTriangle triangle = new TexturedTriangle(
+ new Vertex(new Point3D(0, 0, 0), new Point2D(0, 0)),
+ new Vertex(new Point3D(1, 0, 0), new Point2D(1, 0)),
+ new Vertex(new Point3D(0, 1, 0), new Point2D(0, 1)), null);
+
+ final Method draw = TexturedTriangle.class.getDeclaredMethod(
+ "drawHorizontalLinePerspectiveZ",
+ PerspectiveBorderInterpolator.class, PerspectiveBorderInterpolator.class,
+ int.class, RenderingContext.class, TextureBitmap.class);
+ draw.setAccessible(true);
+
+ final double z = 5.0;
+ final double sw = 1d / z;
+ final int y = 1;
+ final double u1 = 2.0, v1 = 3.0, u2 = 30.0, v2 = 10.0;
+
+ final PerspectiveBorderInterpolator line1 = new PerspectiveBorderInterpolator();
+ final PerspectiveBorderInterpolator line2 = new PerspectiveBorderInterpolator();
+ line1.setPoints(new Point2D(10, y), new Point2D(10, y + 1), u1 * sw, v1 * sw, sw, u1 * sw, v1 * sw, sw);
+ line2.setPoints(new Point2D(190, y), new Point2D(190, y + 1), u2 * sw, v2 * sw, sw, u2 * sw, v2 * sw, sw);
+
+ final RenderingContext context = new RenderingContext(width, height, 1);
+ context.renderMinX = 0;
+ context.renderMaxX = width;
+ java.util.Arrays.fill(context.depth, Float.NEGATIVE_INFINITY);
+ draw.invoke(triangle, line1, line2, y, context, textureBitmap);
+
+ for (int x = 10; x < 190; x++) {
+ final double exactU = u1 + (u2 - u1) * (x - 10) / 180.0;
+ final double exactV = v1 + (v2 - v1) * (x - 10) / 180.0;
+ final int actualTexel = context.pixels[y * width + x] & 0xFFFFFF;
+ final int du = Math.abs((actualTexel % TEX_W) - ((int) exactU));
+ final int dv = Math.abs((actualTexel / TEX_W) - ((int) exactV));
+ assertTrue("pixel " + x + ": texel deviation u=" + du + " v=" + dv,
+ du <= 1 && dv <= 1);
+ }
+ }
+}
--- /dev/null
+/*
+ * Aukio 3D engine. Author: Svjatoslav Agejenko.
+ * This project is released under Creative Commons Zero (CC0) license.
+ */
+package eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.base;
+
+import eu.svjatoslav.aukio.e3d.geometry.Point3D;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Color;
+import eu.svjatoslav.aukio.e3d.renderer.raster.Vertex;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.basic.solidpolygon.SolidPolygon;
+import eu.svjatoslav.aukio.e3d.renderer.raster.shapes.composite.solid.SolidPolygonRectangularBox;
+import org.junit.Test;
+
+import java.util.List;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * Unit tests for the {@link Csg} boolean engine (BSP-based union /
+ * subtract / intersect over polygon lists). This machinery previously
+ * had zero coverage anywhere — no unit test, no golden scene.
+ */
+public class CsgTest {
+
+ private static final double EPS = 1e-9;
+
+ /** Axis-aligned box as a CSG-ready polygon list. */
+ private static List<SolidPolygon> box(final double x1, final double y1,
+ final double z1, final double x2,
+ final double y2, final double z2) {
+ return new SolidPolygonRectangularBox(
+ new Point3D(x1, y1, z1), new Point3D(x2, y2, z2), Color.RED)
+ .extractSolidPolygons();
+ }
+
+ private static double[] centroid(final SolidPolygon polygon) {
+ double cx = 0, cy = 0, cz = 0;
+ for (final Vertex v : polygon.vertices) {
+ cx += v.coordinate.x;
+ cy += v.coordinate.y;
+ cz += v.coordinate.z;
+ }
+ final int n = polygon.vertices.size();
+ return new double[]{cx / n, cy / n, cz / n};
+ }
+
+ /** Strictly inside the box (boundary does NOT count). */
+ private static boolean strictlyInside(final double[] point,
+ final double x1, final double y1,
+ final double z1, final double x2,
+ final double y2, final double z2) {
+ return point[0] > x1 + EPS && point[0] < x2 - EPS
+ && point[1] > y1 + EPS && point[1] < y2 - EPS
+ && point[2] > z1 + EPS && point[2] < z2 - EPS;
+ }
+
+ /** Inside or on the box boundary. */
+ private static boolean insideOrOn(final double x, final double y,
+ final double z,
+ final double x1, final double y1,
+ final double z1, final double x2,
+ final double y2, final double z2) {
+ return x >= x1 - EPS && x <= x2 + EPS
+ && y >= y1 - EPS && y <= y2 + EPS
+ && z >= z1 - EPS && z <= z2 + EPS;
+ }
+
+ private static final List<SolidPolygon> A = box(0, 0, 0, 1, 1, 1);
+ private static final List<SolidPolygon> B = box(0.5, 0.5, 0.5, 1.5, 1.5, 1.5);
+ private static final List<SolidPolygon> FAR = box(10, 10, 10, 11, 11, 11);
+
+ @Test
+ public void unionOfDisjointBoxesKeepsAllFaces() {
+ final List<SolidPolygon> result = Csg.union(A, FAR);
+ assertEquals("6 + 6 faces, no interior to remove",
+ A.size() + FAR.size(), result.size());
+ }
+
+ @Test
+ public void unionOfOverlappingBoxesRemovesInteriorFaces() {
+ final List<SolidPolygon> result = Csg.union(A, B);
+ assertTrue("union of two boxes must produce geometry", !result.isEmpty());
+ // Note: no polygon-COUNT assertion — BSP splits boundary-crossing
+ // faces (raising the count) while removing interior fragments
+ // (lowering it); the net count says nothing. The interior-face
+ // invariant below is the meaningful one.
+ for (final SolidPolygon polygon : result) {
+ final double[] c = centroid(polygon);
+ assertTrue("union must not contain a face strictly inside A",
+ !strictlyInside(c, 0, 0, 0, 1, 1, 1));
+ assertTrue("union must not contain a face strictly inside B",
+ !strictlyInside(c, 0.5, 0.5, 0.5, 1.5, 1.5, 1.5));
+ }
+ }
+
+ @Test
+ public void subtractOfDisjointBoxIsIdentity() {
+ final List<SolidPolygon> result = Csg.subtract(A, FAR);
+ assertEquals(A.size(), result.size());
+ }
+
+ @Test
+ public void subtractLeavesNothingInsideTheCutter() {
+ final List<SolidPolygon> result = Csg.subtract(A, B);
+ assertTrue("carving a corner out of a box must leave geometry",
+ !result.isEmpty());
+ for (final SolidPolygon polygon : result) {
+ final double[] c = centroid(polygon);
+ assertTrue("difference must not contain faces strictly inside the cutter",
+ !strictlyInside(c, 0.5, 0.5, 0.5, 1.5, 1.5, 1.5));
+ }
+ }
+
+ @Test
+ public void intersectOfOverlappingBoxesIsTheOverlapRegion() {
+ final List<SolidPolygon> result = Csg.intersect(A, B);
+ assertTrue("overlap of [0,1]³ and [0.5,1.5]³ must be non-empty",
+ !result.isEmpty());
+ for (final SolidPolygon polygon : result)
+ for (final Vertex v : polygon.vertices) {
+ assertTrue("every vertex must lie inside-or-on A",
+ insideOrOn(v.coordinate.x, v.coordinate.y, v.coordinate.z,
+ 0, 0, 0, 1, 1, 1));
+ assertTrue("every vertex must lie inside-or-on B",
+ insideOrOn(v.coordinate.x, v.coordinate.y, v.coordinate.z,
+ 0.5, 0.5, 0.5, 1.5, 1.5, 1.5));
+ }
+ }
+
+ @Test
+ public void intersectOfDisjointBoxesIsEmpty() {
+ assertTrue(Csg.intersect(A, FAR).isEmpty());
+ }
+
+ @Test
+ public void emptyOperandBehaves() {
+ assertEquals(A.size(), Csg.union(A, List.of()).size());
+ assertEquals(A.size(), Csg.subtract(A, List.of()).size());
+ assertTrue(Csg.intersect(A, List.of()).isEmpty());
+ }
+
+ @Test
+ public void resultsAreDeterministic() {
+ final List<SolidPolygon> first = Csg.union(A, B);
+ final List<SolidPolygon> second = Csg.union(A, B);
+ assertEquals(first.size(), second.size());
+ for (int i = 0; i < first.size(); i++) {
+ final List<Vertex> v1 = first.get(i).vertices;
+ final List<Vertex> v2 = second.get(i).vertices;
+ assertEquals(v1.size(), v2.size());
+ for (int j = 0; j < v1.size(); j++) {
+ assertEquals(v1.get(j).coordinate.x, v2.get(j).coordinate.x, 0.0);
+ assertEquals(v1.get(j).coordinate.y, v2.get(j).coordinate.y, 0.0);
+ assertEquals(v1.get(j).coordinate.z, v2.get(j).coordinate.z, 0.0);
+ }
+ }
+ }
+
+ /** The inputs are never mutated (Csg clones before BSP-ing). */
+ @Test
+ public void inputsAreNotMutated() {
+ final List<SolidPolygon> a = box(0, 0, 0, 1, 1, 1);
+ final double firstX = a.get(0).vertices.get(0).coordinate.x;
+ final int size = a.size();
+ Csg.subtract(a, B);
+ Csg.union(a, B);
+ Csg.intersect(a, B);
+ assertEquals(size, a.size());
+ assertEquals(firstX, a.get(0).vertices.get(0).coordinate.x, 0.0);
+ }
+}
projects / aukio-3d.git / commitdiff
