Improve sky light rendering performance, fix height map bug

Author: MorbZ

README.md

@@ -2,6 +2,8 @@
 
 J2Blocks aims to provide a simple library for custom map generation. In order to use this library it is not necessary to deal with things like regions, chunks and block data. However it aims to implement all map features that Minecraft offers. Please keep in mind that this is still beta.
 
+[→ J2Blocks Documentation](http://docs.morbz.de/j2blocks/)
+
 Example
 ------
 In this example we want to create a Minecraft world that is paved with melon-blocks. We want to create a huge structure of glass and want to set door on top of it. From the [Example.java](https://github.com/MorbZ/J2Blocks/blob/master/doc/Example.java):

src/net/morbz/minecraft/world/Chunk.java

@@ -58,15 +58,18 @@ public class Chunk implements ITagProvider, IBlockContainer {
 	private Section[] sections = new Section[SECTIONS_PER_CHUNK];
 	private int[][] heightMap = new int[BLOCKS_PER_CHUNK_SIDE][BLOCKS_PER_CHUNK_SIDE];
 	private int xPos, zPos;
+	private IBlockContainer parent;
 
 	/**
 	 * Creates a new instance.
 	 * 
-	 * @param xPos The X-coordinate within the chunk
-	 * @param zPos The Z-coordinate within the chunk
+	 * @param parent The parent block container
+	 * @param xPos The X-coordinate within the region
+	 * @param zPos The Z-coordinate within the region
 	 * @param layers The default layers. Can be 'null'
 	 */
-	public Chunk(int xPos, int zPos, DefaultLayers layers) {
+	public Chunk(IBlockContainer parent, int xPos, int zPos, DefaultLayers layers) {
+		this.parent = parent;
 		this.xPos = xPos;
 		this.zPos = zPos;
 
@@ -91,6 +94,20 @@ public Chunk(int xPos, int zPos, DefaultLayers layers) {
 		}
 	}
 
+	/**
+	 * @return The X-coordinate within the region
+	 */
+	public int getX() {
+		return xPos;
+	}
+	
+	/**
+	 * @return The Z-coordinate within the region
+	 */
+	public int getZ() {
+		return zPos;
+	}
+	
 	/**
 	 * Sets a block at the given position.
 	 * 
@@ -112,45 +129,76 @@ public void setBlock(int x, int y, int z, IBlock block) {
 	 * {@inheritDoc}
 	 */
 	@Override
-	public byte getTransparency(int x, int y, int z) {
+	public byte getSkyLight(int x, int y, int z) {
 		// Get section
 		Section section = getSection(y, false);
 
 		if(section != null) {
 			int blockY = y % Section.SECTION_HEIGHT;
-			byte light = section.getTransparency(x, blockY, z);
+			byte light = section.getSkyLight(x, blockY, z);
 			return light;
 		}
-		return World.DEFAULT_TRANSPARENCY;
+		return World.DEFAULT_SKY_LIGHT;
 	}
 
-	/**
-	 * {@inheritDoc}
-	 */
-	@Override
-	public byte getSkyLight(int x, int y, int z) {
+	private void setSkyLight(int x, int y, int z, byte light) {
 		// Get section
 		Section section = getSection(y, false);
 
 		if(section != null) {
 			int blockY = y % Section.SECTION_HEIGHT;
-			byte light = section.getSkyLight(x, blockY, z);
-			return light;
+			section.setSkyLight(x, blockY, z, light);
 		}
-		return World.DEFAULT_SKY_LIGHT;
 	}
 
 	/**
 	 * {@inheritDoc}
 	 */
 	@Override
-	public void setSkyLight(int x, int y, int z, byte light) {
-		// Get section
-		Section section = getSection(y, false);
+	public byte getSkyLightFromParent(IBlockContainer child, int childX, int childY, int childZ) {
+		// Get total Y
+		int y = ((Section)child).getY() * Section.SECTION_HEIGHT + childY;
+		if(y >= World.MAX_HEIGHT) {
+			return World.DEFAULT_SKY_LIGHT;
+		}
+		if(y < 0) {
+			return 0;
+		}
 
-		if(section != null) {
-			int blockY = y % Section.SECTION_HEIGHT;
-			section.setSkyLight(x, blockY, z, light);
+		// Which chunk?
+		if(childX >= 0 && childX < BLOCKS_PER_CHUNK_SIDE && childZ >= 0 && childZ < BLOCKS_PER_CHUNK_SIDE) {
+			// Same chunk
+			return getSkyLight(childX, y, childZ);
+		} else {
+			// Different chunk
+			return parent.getSkyLightFromParent(this, childX, y, childZ);
+		}
+	}
+	
+	/**
+	 * {@inheritDoc}
+	 */
+	@Override
+	public void spreadSkyLight(byte light) {
+		for(Section section : sections) {
+			if(section != null) {
+				section.spreadSkyLight(light);
+			}
+		}
+	}
+	
+	/**
+	 * Adds the sky light. Starts from top the top of each column and sets sky light to full, up to 
+	 * the first non-transparent block.
+	 */
+	public void addSkyLight() {
+		for(int x = 0; x < BLOCKS_PER_CHUNK_SIDE; x++) {
+			for(int z = 0; z < BLOCKS_PER_CHUNK_SIDE; z++) {
+				int highestBlock = getHighestBlock(x, z);
+				for(int y = World.MAX_HEIGHT - 1; y >= highestBlock; y--) {
+					setSkyLight(x, y, z, World.DEFAULT_SKY_LIGHT);
+				}
+			}
 		}
 	}
 
@@ -173,7 +221,7 @@ private Section getSection(int y, boolean create) {
 
 		// Create section
 		if(section == null && create) {
-			section = new Section(sectionY);
+			section = new Section(this, sectionY);
 			sections[sectionY] = section;
 		}
 		return section;
@@ -209,7 +257,7 @@ public void calculateHeightMap() {
 						if(heightMap[x][z] == 0) {
 							int height = section.getHighestBlock(x, z);
 							if(height != -1) {
-								heightMap[x][z] = y * Section.SECTION_HEIGHT +  height;
+								heightMap[x][z] = y * Section.SECTION_HEIGHT + height + 1;
 							}
 						}
 					}

src/net/morbz/minecraft/world/IBlockContainer.java

@@ -1,65 +1,62 @@
-package net.morbz.minecraft.world;
-
-/*
-* The MIT License (MIT)
-* 
-* Copyright (c) 2014-2015 Merten Peetz
-* 
-* Permission is hereby granted, free of charge, to any person obtaining a copy
-* of this software and associated documentation files (the "Software"), to deal
-* in the Software without restriction, including without limitation the rights
-* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-* copies of the Software, and to permit persons to whom the Software is
-* furnished to do so, subject to the following conditions:
-* 
-* The above copyright notice and this permission notice shall be included in all
-* copies or substantial portions of the Software.
-* 
-* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-* SOFTWARE.
-*/
-
-/**
- * The interface for all classes that contain blocks.
- * 
- * @author MorbZ
- */
-public interface IBlockContainer {
-	/**
-	 * Returns the transparency level of the block at given position. If there is no block 
-	 * World.DEFAULT_TRANSPARENCY will be returned. 0 means fully opaque, 1 means fully transparent
-	 * and values > 1 mean transparent but the light level is decreased by n at this block.
-	 * 
-	 * @param x The local X-coordinate
-	 * @param y The local Y-coordinate
-	 * @param z The local Z-coordinate
-	 * @return The transparency level
-	 */
-	public byte getTransparency(int x, int y, int z);
-	
-	/**
-	 * Returns the sky light level of the block at given position. If there is no block 
-	 * World.DEFAULT_SKY_LIGHT will be returned.
-	 * 
-	 * @param x The local X-coordinate
-	 * @param y The local Y-coordinate
-	 * @param z The local Z-coordinate
-	 * @return The transparency level
-	 */
-	public byte getSkyLight(int x, int y, int z);
-	
-	/**
-	 * Sets the sky light level of the block at given position.
-	 * 
-	 * @param x The local X-coordinate
-	 * @param y The local Y-coordinate
-	 * @param z The local Z-coordinate
-	 * @param light The sky light level
-	 */
-	public void setSkyLight(int x, int y, int z, byte light);
-}
+package net.morbz.minecraft.world;
+
+/*
+* The MIT License (MIT)
+* 
+* Copyright (c) 2014-2015 Merten Peetz
+* 
+* Permission is hereby granted, free of charge, to any person obtaining a copy
+* of this software and associated documentation files (the "Software"), to deal
+* in the Software without restriction, including without limitation the rights
+* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+* copies of the Software, and to permit persons to whom the Software is
+* furnished to do so, subject to the following conditions:
+* 
+* The above copyright notice and this permission notice shall be included in all
+* copies or substantial portions of the Software.
+* 
+* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+* SOFTWARE.
+*/
+
+/**
+ * The interface for all classes that contain blocks.
+ * 
+ * @author MorbZ
+ */
+public interface IBlockContainer {
+	/**
+	 * Returns the sky light level of the block at given position. If there is no block 
+	 * World.DEFAULT_SKY_LIGHT will be returned.
+	 * 
+	 * @param x The local X-coordinate
+	 * @param y The local Y-coordinate
+	 * @param z The local Z-coordinate
+	 * @return The sky light level
+	 */
+	public byte getSkyLight(int x, int y, int z);
+	
+	/**
+	 * Returns the sky light level of a block that is out of bounds of the child block container.
+	 * 
+	 * @param child The child block container
+	 * @param childX The local X-coordinate
+	 * @param childY The local Y-coordinate
+	 * @param childZ The local Z-coordinate
+	 * @return The sky light level
+	 */
+	public byte getSkyLightFromParent(IBlockContainer child, int childX, int childY, int childZ);
+	
+	/**
+	 * Spreads the skylight. For each block that has the given light level it's adjacent blocks will
+	 * be lit if their current light level is lower.
+	 * 
+	 * @param light The light level
+	 */
+	public void spreadSkyLight(byte light);
+}