src/main/java/eu/svjatoslav/sixth/e3d/renderer/raster/shapes/basic/texturedpolygon/TexturedPolygon.java

   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.geometry.Point3D;
   9 import eu.svjatoslav.sixth.e3d.gui.RenderingContext;
  10 import eu.svjatoslav.sixth.e3d.renderer.raster.shapes.AbstractCoordinateShape;
  11 import eu.svjatoslav.sixth.e3d.renderer.raster.slicer.PolygonCoordinate;
  12 import eu.svjatoslav.sixth.e3d.renderer.raster.texture.Texture;
  13 import eu.svjatoslav.sixth.e3d.renderer.raster.texture.TextureBitmap;
  14
  15 import java.awt.*;
  16
  17 import static eu.svjatoslav.sixth.e3d.geometry.Polygon.pointWithinPolygon;
  18 import static java.util.Arrays.sort;
  19
  20 /**
  21  * Textured polygon.
  22  * <p>
  23  *
  24  * <pre>
  25  * This is how perspective-correct texture rendering is implemented:
  26  * If polygon is sufficiently small, it is rendered without perspective correction.
  27  * Otherwise, it is sliced into smaller polygons.
  28  * </pre>
  29  */
  30
  31 public class TexturedPolygon extends AbstractCoordinateShape {
  32
  33     public final Texture texture;
  34     /**
  35      * Polygon texture coordinates.
  36      */
  37     public Point2D texturePoint1, texturePoint2, texturePoint3;
  38
  39     /**
  40      * If <code>true</code> then polygon borders will be drawn.
  41      * It is used for debugging purposes.
  42      */
  43     public boolean showBorders = false;
  44     private double totalTextureDistance = -1;
  45
  46     public TexturedPolygon(final Point3D p1, final Point3D p2,
  47                            final Point3D p3, final Point2D tp1, final Point2D tp2,
  48                            final Point2D tp3, final Texture texture) {
  49
  50         super(p1, p2, p3);
  51
  52         texturePoint1 = tp1;
  53         texturePoint2 = tp2;
  54         texturePoint3 = tp3;
  55
  56         this.texture = texture;
  57     }
  58
  59     public TexturedPolygon(final PolygonCoordinate pc1,
  60                            final PolygonCoordinate pc2, final PolygonCoordinate pc3,
  61                            final Texture texture) {
  62
  63         this(pc1.spaceCoordinate, pc2.spaceCoordinate, pc3.spaceCoordinate, pc1.textureCoordinate, pc2.textureCoordinate,
  64                 pc3.textureCoordinate, texture);
  65     }
  66
  67     private void computeTotalTextureDistance() {
  68         // compute total texture distance
  69         totalTextureDistance = texturePoint1.getDistanceTo(texturePoint2);
  70         totalTextureDistance += texturePoint1.getDistanceTo(texturePoint3);
  71         totalTextureDistance += texturePoint2.getDistanceTo(texturePoint3);
  72     }
  73
  74     private void drawHorizontalLine(final PolygonBorderInterpolator line1,
  75                                     final PolygonBorderInterpolator line2, final int y,
  76                                     final RenderingContext renderBuffer,
  77                                     final TextureBitmap textureBitmap) {
  78
  79         line1.setCurrentY(y);
  80         line2.setCurrentY(y);
  81
  82         int x1 = line1.getX();
  83         int x2 = line2.getX();
  84
  85         final double tx2, ty2;
  86         final double tx1, ty1;
  87
  88         if (x1 <= x2) {
  89
  90             tx1 = line1.getTX() * textureBitmap.multiplicationFactor;
  91             ty1 = line1.getTY() * textureBitmap.multiplicationFactor;
  92
  93             tx2 = line2.getTX() * textureBitmap.multiplicationFactor;
  94             ty2 = line2.getTY() * textureBitmap.multiplicationFactor;
  95
  96         } else {
  97             final int tmp = x1;
  98             x1 = x2;
  99             x2 = tmp;
 100
 101             tx1 = line2.getTX() * textureBitmap.multiplicationFactor;
 102             ty1 = line2.getTY() * textureBitmap.multiplicationFactor;
 103
 104             tx2 = line1.getTX() * textureBitmap.multiplicationFactor;
 105             ty2 = line1.getTY() * textureBitmap.multiplicationFactor;
 106         }
 107
 108         final double realWidth = x2 - x1;
 109         final double realX1 = x1;
 110
 111         if (x1 < 0)
 112             x1 = 0;
 113
 114         if (x2 >= renderBuffer.width)
 115             x2 = renderBuffer.width - 1;
 116
 117         int renderBufferOffset = ((y * renderBuffer.width) + x1) * 4;
 118         final byte[] renderBufferBytes = renderBuffer.pixels;
 119
 120         final double twidth = tx2 - tx1;
 121         final double theight = ty2 - ty1;
 122
 123         for (int x = x1; x < x2; x++) {
 124
 125             final double distance = x - realX1;
 126
 127             final double tx = tx1 + ((twidth * distance) / realWidth);
 128             final double ty = ty1 + ((theight * distance) / realWidth);
 129
 130             final int textureOffset = textureBitmap.getAddress((int) tx,
 131                     (int) ty);
 132
 133             textureBitmap.drawPixel(textureOffset, renderBufferBytes,
 134                     renderBufferOffset);
 135
 136             renderBufferOffset += 4;
 137         }
 138
 139     }
 140
 141     @Override
 142     public void paint(final RenderingContext renderBuffer) {
 143
 144         final Point2D projectedPoint1 = coordinates[0].onScreenCoordinate;
 145         final Point2D projectedPoint2 = coordinates[1].onScreenCoordinate;
 146         final Point2D projectedPoint3 = coordinates[2].onScreenCoordinate;
 147
 148         projectedPoint1.roundToInteger();
 149         projectedPoint2.roundToInteger();
 150         projectedPoint3.roundToInteger();
 151
 152         if (mouseInteractionController != null)
 153             if (renderBuffer.getMouseEvent() != null)
 154                 if (pointWithinPolygon(
 155                         renderBuffer.getMouseEvent().coordinate, projectedPoint1,
 156                         projectedPoint2, projectedPoint3))
 157                     renderBuffer.setCurrentObjectUnderMouseCursor(mouseInteractionController);
 158
 159         // Show polygon boundaries (for debugging)
 160         if (showBorders)
 161             showBorders(renderBuffer);
 162
 163         // find top-most point
 164         int yTop = (int) projectedPoint1.y;
 165
 166         if (projectedPoint2.y < yTop)
 167             yTop = (int) projectedPoint2.y;
 168
 169         if (projectedPoint3.y < yTop)
 170             yTop = (int) projectedPoint3.y;
 171
 172         if (yTop < 0)
 173             yTop = 0;
 174
 175         // find bottom-most point
 176         int yBottom = (int) projectedPoint1.y;
 177
 178         if (projectedPoint2.y > yBottom)
 179             yBottom = (int) projectedPoint2.y;
 180
 181         if (projectedPoint3.y > yBottom)
 182             yBottom = (int) projectedPoint3.y;
 183
 184         if (yBottom >= renderBuffer.height)
 185             yBottom = renderBuffer.height - 1;
 186
 187         // paint
 188         double totalVisibleDistance = projectedPoint1.getDistanceTo(projectedPoint2);
 189         totalVisibleDistance += projectedPoint1.getDistanceTo(projectedPoint3);
 190         totalVisibleDistance += projectedPoint2.getDistanceTo(projectedPoint3);
 191
 192         if (totalTextureDistance == -1)
 193             computeTotalTextureDistance();
 194         final double scaleFactor = (totalVisibleDistance / totalTextureDistance) * 1.2d;
 195
 196         final TextureBitmap zoomedBitmap = texture.getZoomedBitmap(scaleFactor);
 197
 198         final PolygonBorderInterpolator[] is = new PolygonBorderInterpolator[]{
 199                 new PolygonBorderInterpolator(), new PolygonBorderInterpolator(),
 200                 new PolygonBorderInterpolator()};
 201
 202         is[0].setPoints(projectedPoint1, projectedPoint2, texturePoint1,
 203                 texturePoint2);
 204         is[1].setPoints(projectedPoint1, projectedPoint3, texturePoint1,
 205                 texturePoint3);
 206         is[2].setPoints(projectedPoint2, projectedPoint3, texturePoint2,
 207                 texturePoint3);
 208
 209         sort(is);
 210
 211         for (int y = yTop; y < yBottom; y++)
 212             if (is[0].containsY(y)) {
 213
 214                 if (is[1].containsY(y))
 215                     drawHorizontalLine(is[0], is[1], y, renderBuffer,
 216                             zoomedBitmap);
 217                 else if (is[2].containsY(y))
 218                     drawHorizontalLine(is[0], is[2], y, renderBuffer,
 219                             zoomedBitmap);
 220             } else if (is[1].containsY(y))
 221                 if (is[2].containsY(y))
 222                     drawHorizontalLine(is[1], is[2], y, renderBuffer,
 223                             zoomedBitmap);
 224
 225     }
 226
 227     private void showBorders(final RenderingContext renderBuffer) {
 228
 229         final Point2D projectedPoint1 = coordinates[0].onScreenCoordinate;
 230         final Point2D projectedPoint2 = coordinates[1].onScreenCoordinate;
 231         final Point2D projectedPoint3 = coordinates[2].onScreenCoordinate;
 232
 233         renderBuffer.graphics.setColor(Color.YELLOW);
 234         renderBuffer.graphics.drawLine((int) projectedPoint1.x,
 235                 (int) projectedPoint1.y, (int) projectedPoint2.x,
 236                 (int) projectedPoint2.y);
 237         renderBuffer.graphics.drawLine((int) projectedPoint3.x,
 238                 (int) projectedPoint3.y, (int) projectedPoint2.x,
 239                 (int) projectedPoint2.y);
 240         renderBuffer.graphics.drawLine((int) projectedPoint1.x,
 241                 (int) projectedPoint1.y, (int) projectedPoint3.x,
 242                 (int) projectedPoint3.y);
 243     }
 244
 245 }