www2.svjatoslav.eu Git - sixth-3d.git/blob

   1 /*
   2  * Sixth 3D engine. Author: Svjatoslav Agejenko.
   3  * This project is released under Creative Commons Zero (CC0) license.
   4  */
   5 package eu.svjatoslav.sixth.e3d.renderer.raster.shapes.basic.texturedpolygon;
   6
   7 import eu.svjatoslav.sixth.e3d.geometry.Point2D;
   8 import eu.svjatoslav.sixth.e3d.gui.RenderingContext;
   9 import eu.svjatoslav.sixth.e3d.math.Vertex;
  10 import eu.svjatoslav.sixth.e3d.renderer.raster.shapes.AbstractCoordinateShape;
  11 import eu.svjatoslav.sixth.e3d.renderer.raster.texture.Texture;
  12 import eu.svjatoslav.sixth.e3d.renderer.raster.texture.TextureBitmap;
  13
  14 import java.awt.Color;
  15
  16 import static eu.svjatoslav.sixth.e3d.geometry.Polygon.pointWithinPolygon;
  17
  18 /**
  19  * Textured polygon.
  20  * <p>
  21  *
  22  * <pre>
  23  * This is how perspective-correct texture rendering is implemented:
  24  * If polygon is sufficiently small, it is rendered without perspective correction.
  25  * Otherwise, it is sliced into smaller polygons.
  26  * </pre>
  27  */
  28
  29 public class TexturedPolygon extends AbstractCoordinateShape {
  30
  31     private static final PolygonBorderInterpolator polygonBorder1 = new PolygonBorderInterpolator();
  32     private static final PolygonBorderInterpolator polygonBorder2 = new PolygonBorderInterpolator();
  33     private static final PolygonBorderInterpolator polygonBorder3 = new PolygonBorderInterpolator();
  34
  35     public final Texture texture;
  36
  37     /**
  38      * If <code>true</code> then polygon borders will be drawn.
  39      * It is used for debugging purposes.
  40      */
  41     public boolean showBorders = false;
  42     private boolean backfaceCulling = false;
  43
  44     private double totalTextureDistance = -1;
  45
  46     public TexturedPolygon(Vertex p1, Vertex p2, Vertex p3, final Texture texture) {
  47
  48         super(p1, p2, p3);
  49         this.texture = texture;
  50     }
  51
  52     private void computeTotalTextureDistance() {
  53         // compute total texture distance
  54         totalTextureDistance = coordinates[0].textureCoordinate.getDistanceTo(coordinates[1].textureCoordinate);
  55         totalTextureDistance += coordinates[0].textureCoordinate.getDistanceTo(coordinates[2].textureCoordinate);
  56         totalTextureDistance += coordinates[1].textureCoordinate.getDistanceTo(coordinates[2].textureCoordinate);
  57     }
  58
  59     private void drawHorizontalLine(final PolygonBorderInterpolator line1,
  60                                     final PolygonBorderInterpolator line2, final int y,
  61                                     final RenderingContext renderBuffer,
  62                                     final TextureBitmap textureBitmap) {
  63
  64         line1.setCurrentY(y);
  65         line2.setCurrentY(y);
  66
  67         int x1 = line1.getX();
  68         int x2 = line2.getX();
  69
  70         final double tx2, ty2;
  71         final double tx1, ty1;
  72
  73         if (x1 <= x2) {
  74
  75             tx1 = line1.getTX() * textureBitmap.multiplicationFactor;
  76             ty1 = line1.getTY() * textureBitmap.multiplicationFactor;
  77
  78             tx2 = line2.getTX() * textureBitmap.multiplicationFactor;
  79             ty2 = line2.getTY() * textureBitmap.multiplicationFactor;
  80
  81         } else {
  82             final int tmp = x1;
  83             x1 = x2;
  84             x2 = tmp;
  85
  86             tx1 = line2.getTX() * textureBitmap.multiplicationFactor;
  87             ty1 = line2.getTY() * textureBitmap.multiplicationFactor;
  88
  89             tx2 = line1.getTX() * textureBitmap.multiplicationFactor;
  90             ty2 = line1.getTY() * textureBitmap.multiplicationFactor;
  91         }
  92
  93         final double realWidth = x2 - x1;
  94         final double realX1 = x1;
  95
  96         if (x1 < 0)
  97             x1 = 0;
  98
  99         if (x2 >= renderBuffer.width)
 100             x2 = renderBuffer.width - 1;
 101
 102         int renderBufferOffset = ((y * renderBuffer.width) + x1) * 4;
 103         final byte[] renderBufferBytes = renderBuffer.pixels;
 104
 105         final double twidth = tx2 - tx1;
 106         final double theight = ty2 - ty1;
 107
 108         for (int x = x1; x < x2; x++) {
 109
 110             final double distance = x - realX1;
 111
 112             final double tx = tx1 + ((twidth * distance) / realWidth);
 113             final double ty = ty1 + ((theight * distance) / realWidth);
 114
 115             final int textureOffset = textureBitmap.getAddress((int) tx,
 116                     (int) ty);
 117
 118             textureBitmap.drawPixel(textureOffset, renderBufferBytes,
 119                     renderBufferOffset);
 120
 121             renderBufferOffset += 4;
 122         }
 123
 124     }
 125
 126     @Override
 127     public void paint(final RenderingContext renderBuffer) {
 128
 129         final Point2D projectedPoint1 = coordinates[0].onScreenCoordinate;
 130         final Point2D projectedPoint2 = coordinates[1].onScreenCoordinate;
 131         final Point2D projectedPoint3 = coordinates[2].onScreenCoordinate;
 132
 133         if (backfaceCulling) {
 134             final double signedArea = (projectedPoint2.x - projectedPoint1.x)
 135                     * (projectedPoint3.y - projectedPoint1.y)
 136                     - (projectedPoint3.x - projectedPoint1.x)
 137                     * (projectedPoint2.y - projectedPoint1.y);
 138             if (signedArea >= 0)
 139                 return;
 140         }
 141
 142         projectedPoint1.roundToInteger();
 143         projectedPoint2.roundToInteger();
 144         projectedPoint3.roundToInteger();
 145
 146         if (mouseInteractionController != null)
 147             if (renderBuffer.getMouseEvent() != null)
 148                 if (pointWithinPolygon(
 149                         renderBuffer.getMouseEvent().coordinate, projectedPoint1,
 150                         projectedPoint2, projectedPoint3))
 151                     renderBuffer.setCurrentObjectUnderMouseCursor(mouseInteractionController);
 152
 153         // Show polygon boundaries (for debugging)
 154         if (showBorders)
 155             showBorders(renderBuffer);
 156
 157         // find top-most point
 158         int yTop = (int) projectedPoint1.y;
 159
 160         if (projectedPoint2.y < yTop)
 161             yTop = (int) projectedPoint2.y;
 162
 163         if (projectedPoint3.y < yTop)
 164             yTop = (int) projectedPoint3.y;
 165
 166         if (yTop < 0)
 167             yTop = 0;
 168
 169         // find bottom-most point
 170         int yBottom = (int) projectedPoint1.y;
 171
 172         if (projectedPoint2.y > yBottom)
 173             yBottom = (int) projectedPoint2.y;
 174
 175         if (projectedPoint3.y > yBottom)
 176             yBottom = (int) projectedPoint3.y;
 177
 178         if (yBottom >= renderBuffer.height)
 179             yBottom = renderBuffer.height - 1;
 180
 181         // paint
 182         double totalVisibleDistance = projectedPoint1.getDistanceTo(projectedPoint2);
 183         totalVisibleDistance += projectedPoint1.getDistanceTo(projectedPoint3);
 184         totalVisibleDistance += projectedPoint2.getDistanceTo(projectedPoint3);
 185
 186         if (totalTextureDistance == -1)
 187             computeTotalTextureDistance();
 188         final double scaleFactor = (totalVisibleDistance / totalTextureDistance) * 1.2d;
 189
 190         final TextureBitmap zoomedBitmap = texture.getZoomedBitmap(scaleFactor);
 191
 192         polygonBorder1.setPoints(projectedPoint1, projectedPoint2,
 193                 coordinates[0].textureCoordinate,
 194                 coordinates[1].textureCoordinate);
 195         polygonBorder2.setPoints(projectedPoint1, projectedPoint3,
 196                 coordinates[0].textureCoordinate,
 197                 coordinates[2].textureCoordinate);
 198         polygonBorder3.setPoints(projectedPoint2, projectedPoint3,
 199                 coordinates[1].textureCoordinate,
 200                 coordinates[2].textureCoordinate);
 201
 202         // Inline sort for 3 elements to avoid array allocation
 203         PolygonBorderInterpolator a = polygonBorder1;
 204         PolygonBorderInterpolator b = polygonBorder2;
 205         PolygonBorderInterpolator c = polygonBorder3;
 206         PolygonBorderInterpolator t;
 207         if (a.compareTo(b) > 0) { t = a; a = b; b = t; }
 208         if (b.compareTo(c) > 0) { t = b; b = c; c = t; }
 209         if (a.compareTo(b) > 0) { t = a; a = b; b = t; }
 210
 211         for (int y = yTop; y < yBottom; y++)
 212             if (a.containsY(y)) {
 213                 if (b.containsY(y))
 214                     drawHorizontalLine(a, b, y, renderBuffer, zoomedBitmap);
 215                 else if (c.containsY(y))
 216                     drawHorizontalLine(a, c, y, renderBuffer, zoomedBitmap);
 217             } else if (b.containsY(y))
 218                 if (c.containsY(y))
 219                     drawHorizontalLine(b, c, y, renderBuffer, zoomedBitmap);
 220
 221     }
 222
 223     public boolean isBackfaceCullingEnabled() {
 224         return backfaceCulling;
 225     }
 226
 227     public void setBackfaceCulling(final boolean backfaceCulling) {
 228         this.backfaceCulling = backfaceCulling;
 229     }
 230
 231     private void showBorders(final RenderingContext renderBuffer) {
 232
 233         final Point2D projectedPoint1 = coordinates[0].onScreenCoordinate;
 234         final Point2D projectedPoint2 = coordinates[1].onScreenCoordinate;
 235         final Point2D projectedPoint3 = coordinates[2].onScreenCoordinate;
 236
 237         renderBuffer.graphics.setColor(Color.YELLOW);
 238         renderBuffer.graphics.drawLine((int) projectedPoint1.x,
 239                 (int) projectedPoint1.y, (int) projectedPoint2.x,
 240                 (int) projectedPoint2.y);
 241         renderBuffer.graphics.drawLine((int) projectedPoint3.x,
 242                 (int) projectedPoint3.y, (int) projectedPoint2.x,
 243                 (int) projectedPoint2.y);
 244         renderBuffer.graphics.drawLine((int) projectedPoint1.x,
 245                 (int) projectedPoint1.y, (int) projectedPoint3.x,
 246                 (int) projectedPoint3.y);
 247     }
 248
 249 }