src/main/java/eu/svjatoslav/sixth/e3d/renderer/raster/shapes/basic/GlowingPoint.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;
   6
   7 import eu.svjatoslav.sixth.e3d.geometry.Point3D;
   8 import eu.svjatoslav.sixth.e3d.renderer.raster.Color;
   9 import eu.svjatoslav.sixth.e3d.renderer.raster.texture.Texture;
  10
  11 import java.util.Collections;
  12 import java.util.Set;
  13 import java.util.WeakHashMap;
  14
  15 import static java.lang.Math.pow;
  16 import static java.lang.Math.sqrt;
  17
  18 public class GlowingPoint extends ForwardOrientedTexture {
  19
  20     private static final int TEXTURE_RESOLUTION_PIXELS = 100;
  21     /**
  22      * A set of all existing glowing points.
  23      * Used to reuse textures of glowing points of the same color.
  24      */
  25     private static final Set<GlowingPoint> glowingPoints = Collections.newSetFromMap(new WeakHashMap<>());
  26     private final Color color;
  27
  28     public GlowingPoint(final Point3D point, final double pointSize,
  29                         final Color color) {
  30         super(point, computeScale(pointSize), getTexture(color));
  31         this.color = color;
  32
  33         synchronized (glowingPoints) {
  34             glowingPoints.add(this);
  35         }
  36     }
  37
  38
  39     private static double computeScale(double pointSize) {
  40         return pointSize / ((double) (TEXTURE_RESOLUTION_PIXELS / 50f));
  41     }
  42
  43     /**
  44      * Returns a texture for a glowing point of the given color.
  45      * The texture is a circle with a gradient from transparent to the given color.
  46      */
  47     private static Texture getTexture(final Color color) {
  48         // attempt to reuse texture from existing glowing point of the same color
  49         synchronized (glowingPoints) {
  50             for (GlowingPoint glowingPoint : glowingPoints)
  51                 if (color.equals(glowingPoint.color))
  52                     return glowingPoint.texture;
  53         }
  54
  55         // existing texture not found, creating new one
  56         return createTexture(color);
  57     }
  58
  59     /**
  60      * Creates a texture for a glowing point of the given color.
  61      * The texture is a circle with a gradient from transparent to the given color.
  62      */
  63     private static Texture createTexture(final Color color) {
  64         final Texture texture = new Texture(TEXTURE_RESOLUTION_PIXELS, TEXTURE_RESOLUTION_PIXELS, 1);
  65         int halfResolution = TEXTURE_RESOLUTION_PIXELS / 2;
  66
  67         for (int x = 0; x < TEXTURE_RESOLUTION_PIXELS; x++)
  68             for (int y = 0; y < TEXTURE_RESOLUTION_PIXELS; y++) {
  69                 int address = texture.primaryBitmap.getAddress(x, y);
  70
  71                 final int distanceFromCenter = (int) sqrt(pow (halfResolution - x, 2) + pow (halfResolution - y, 2));
  72
  73                 int alpha = 255 - ((270 * distanceFromCenter) / halfResolution);
  74                 if (alpha < 0)
  75                     alpha = 0;
  76
  77                 texture.primaryBitmap.bytes[address] = (byte) alpha;
  78                 address++;
  79                 texture.primaryBitmap.bytes[address] = (byte) color.b;
  80                 address++;
  81                 texture.primaryBitmap.bytes[address] = (byte) color.g;
  82                 address++;
  83                 texture.primaryBitmap.bytes[address] = (byte) color.r;
  84             }
  85
  86         return texture;
  87     }
  88
  89 }