Fix incorrect dark oak leaf color blending issue

The same render model was used for both LEAVES and LEAVES2, causing dark
oak leaves to be treated as spruce leaves and acacia leaves to be treated
as birch leaves.

fixes #467 (github)

Author: llbit

ChangeLog.txt

@@ -1,5 +1,6 @@
 LATEST
 
+* Fixed incorrect dark oak leaf color blending.
 * Added new solid color sky mode.
 * Fixed wrong texture for pink and gray glazed terracotta.
 

chunky/src/java/se/llbit/chunky/block/Block.java

@@ -89,6 +89,7 @@
 import se.llbit.chunky.world.Material;
 import se.llbit.json.JsonString;
 import se.llbit.json.JsonValue;
+import se.llbit.math.ColorUtil;
 import se.llbit.math.Ray;
 
 import java.util.Arrays;
@@ -113,7 +114,7 @@ public class Block extends Material {
   private static final boolean UNKNOWN_INVISIBLE = !PersistentSettings.drawUnknownBlocks();
 
   public static final int AIR_ID = 0x00;
-  public static final Block AIR = new Block(AIR_ID, "Air", Texture.air);
+  public static final Block AIR = new Block(AIR_ID, "block:air", Texture.air);
   public static final int STONE_ID = 0x01;
   public static final Block STONE = new Block(STONE_ID, "block:stone", Texture.stone) {
     final Texture[] texture = {
@@ -277,12 +278,31 @@ public class Block extends Material {
   };
   public static final int LEAVES_ID = 0x12;
   public static final Block LEAVES = new Block(LEAVES_ID, "block:leaves", Texture.oakLeaves) {
-    final Texture[] texture =
-        {Texture.oakLeaves, Texture.spruceLeaves, Texture.birchLeaves, Texture.jungleTreeLeaves};
+    private final float[] SPRUCE_COLOR = new float[4];
+    private final float[] BIRCH_COLOR = new float[4];
 
-    @Override public boolean intersect(Ray ray, Scene scene) {
-      return LeafModel.intersect(ray, scene, getTexture(ray.getBlockData()));
+    {
+      // Spruce and birch colors are hard-coded.
+      ColorUtil.getRGBAComponents(0x2b472b, SPRUCE_COLOR);
+      ColorUtil.getRGBAComponents(0x3a4e25, BIRCH_COLOR);
+    }
+
+    final Texture[] texture = {
+        Texture.oakLeaves, Texture.spruceLeaves, Texture.birchLeaves, Texture.jungleTreeLeaves
+    };
 
+    @Override public boolean intersect(Ray ray, Scene scene) {
+      int data = ray.getBlockData();
+      switch (data) {
+        case 1:
+          // Spruce leaf color is not based on biome.
+          return LeafModel.intersect(ray, getTexture(data), SPRUCE_COLOR);
+        case 2:
+          // Birch leaf color is not based on biome.
+          return LeafModel.intersect(ray, getTexture(data), BIRCH_COLOR);
+        default:
+          return LeafModel.intersect(ray, scene, getTexture(data));
+      }
     }
 
     final String[] woodType = {"oak", "spruce", "birch", "jungle",};

chunky/src/java/se/llbit/chunky/model/LeafModel.java

@@ -25,32 +25,17 @@
 public class LeafModel {
   private static final AABB block = new AABB(0, 1, 0, 1, 0, 1);
 
-  private static final float[] SPRUCE_COLOR = new float[4];
-  private static final float[] BIRCH_COLOR = new float[4];
-
-  static {
-    // Spruce and birch colors are hard-coded.
-    ColorUtil.getRGBAComponents(0x2b472b, SPRUCE_COLOR);
-    ColorUtil.getRGBAComponents(0x3a4e25, BIRCH_COLOR);
-  }
-
+  /**
+   * Get leaf color at ray intersection, based on biome.
+   */
   public static boolean intersect(Ray ray, Scene scene, Texture texture) {
     ray.t = Double.POSITIVE_INFINITY;
     if (block.intersect(ray)) {
       float[] color = texture.getColor(ray.u, ray.v);
       if (color[3] > Ray.EPSILON) {
         ray.color.set(color);
         float[] biomeColor;
-        int woodType = ray.getBlockData();
-        if (woodType == 1) {
-          // Use constant spruce color:
-          biomeColor = SPRUCE_COLOR;
-        } else if (woodType == 2) {
-          // Use constant birch color:
-          biomeColor = BIRCH_COLOR;
-        } else {
-          biomeColor = ray.getBiomeFoliageColor(scene);
-        }
+        biomeColor = ray.getBiomeFoliageColor(scene);
         ray.color.x *= biomeColor[0];
         ray.color.y *= biomeColor[1];
         ray.color.z *= biomeColor[2];
@@ -61,4 +46,26 @@ public static boolean intersect(Ray ray, Scene scene, Texture texture) {
     }
     return false;
   }
+
+  /**
+   * Get leaf color at ray intersection, using base leaf color.
+   *
+   * @param leafColor base leaf color to blend the leaf texture with.
+   */
+  public static boolean intersect(Ray ray, Texture texture, float[] leafColor) {
+    ray.t = Double.POSITIVE_INFINITY;
+    if (block.intersect(ray)) {
+      float[] color = texture.getColor(ray.u, ray.v);
+      if (color[3] > Ray.EPSILON) {
+        ray.color.set(color);
+        ray.color.x *= leafColor[0];
+        ray.color.y *= leafColor[1];
+        ray.color.z *= leafColor[2];
+        ray.distance += ray.tNext;
+        ray.o.scaleAdd(ray.tNext, ray.d);
+        return true;
+      }
+    }
+    return false;
+  }
 }