Near-perfect match Minecraft map shading

src/main/java/baritone/map/MapChunk.java

@@ -4,7 +4,9 @@ import baritone.bot.Baritone;
 import baritone.bot.utils.BlockStateInterface;
 import baritone.bot.utils.pathing.BetterBlockPos;
 import net.minecraft.block.material.MapColor;
+import net.minecraft.init.Blocks;
 import net.minecraft.util.EnumFacing;
+import net.minecraft.util.math.BlockPos;
 import net.minecraft.util.math.BlockPos.MutableBlockPos;
 import net.minecraft.world.chunk.Chunk;
 import org.lwjgl.util.Color;
@@ -52,21 +54,45 @@ public class MapChunk {
         return new File(new File(Baritone.INSTANCE.getDir(), "map"), "chunk" + chunk.x + "-" + chunk.z + ".png").toPath();
     }
 
+    /**
+     * getColor is a re-implementation of the Minecraft ItemMap's
+     * surface mapping system. This is significantly less convoluted
+     * than the poorly de-obfuscated code.
+     *
+     * We perform shading of the given coordinate relative to the
+     * position one to the north of the coordinate, as can be seen
+     * in Minecraft's maps.
+     *
+     * @param x relative x coordinate to the start of the chunk
+     * @param z relative z coord.
+     * @return Integer RGB value with contextual shading
+     */
     public int getColor(int x, int z) {
         int chunkX = chunk.getPos().getXStart() + x;
         int chunkZ = chunk.getPos().getZStart() + z;
         MutableBlockPos blockPos = new MutableBlockPos(chunkX, chunk.getHeight(new BetterBlockPos(chunkX, 0, chunkZ)), chunkZ);
         MapColor color = BlockStateInterface.get(blockPos).getMapColor(chunk.getWorld(), blockPos);
-        int colorValue = color != MapColor.AIR ? color.colorValue : BlockStateInterface.get(blockPos.move(EnumFacing.DOWN)).getMapColor(chunk.getWorld(), blockPos).colorValue;
+
+        // The chunk heightMap returns the first non-full block above the surface, including bushes.
+        // We have to check this and shift our block down by one if the color is "air" (as in, there's no real block there)
+        int colorValue = color != MapColor.AIR ? color.colorValue : BlockStateInterface.get(blockPos.down()).getMapColor(chunk.getWorld(), blockPos).colorValue;
         int red = (colorValue >> 16) & 0xFF;
         int green = (colorValue >> 8) & 0xFF;
         int blue = colorValue & 0xFF;
 
-        float heightCoef = (((float) blockPos.getY()) / 255) + 0.5f;
+        // Now we get the proper block for the position one to the north.
-        colorValue = (int) (red * heightCoef);
+        BlockPos offset = blockPos.offset(EnumFacing.NORTH);
-        colorValue = (colorValue << 8) + (int) (green * heightCoef);
+        offset = new BlockPos(offset.getX(), chunk.getHeight(offset), offset.getZ());
-        colorValue = (colorValue << 8) + (int) (blue * heightCoef);
+        // And once again, check to make sure we have an actual colored block an not "air"
-        return colorValue;
+        if(BlockStateInterface.get(offset).getMapColor(chunk.getWorld(), offset) == MapColor.AIR)
+            offset = offset.down();
+
+        // We start the heightCoef at 0.8 to darken the colors similar to vanilla Minecraft's. 
+        float heightCoef = 0.8f + (Math.signum(blockPos.getY() - offset.getY()) * 0.2f);
+        int newColor = Math.min(255, (int) (red * heightCoef));
+        newColor = (newColor << 8) + Math.min(255, (int) (green * heightCoef));
+        newColor = (newColor << 8) + Math.min(255, (int) (blue * heightCoef));
+        return newColor;
     }
 
 }