From d3639bd4a61f6f20877d119b7e22bc5c9a6af449 Mon Sep 17 00:00:00 2001
From: Mike Primm <mike@primmhome.com>
Date: Sat, 4 Dec 2021 03:01:39 -0600
Subject: [PATCH] Add generic chunk, and builder

---
 .../org/dynmap/common/chunk/DynmapChunk.java  | 100 ++++++++++++++++++
 .../common/chunk/DynmapChunkSection.java      |   4 +
 2 files changed, 104 insertions(+)
 create mode 100644 DynmapCore/src/main/java/org/dynmap/common/chunk/DynmapChunk.java

diff --git a/DynmapCore/src/main/java/org/dynmap/common/chunk/DynmapChunk.java b/DynmapCore/src/main/java/org/dynmap/common/chunk/DynmapChunk.java
new file mode 100644
index 00000000..af25034a
--- /dev/null
+++ b/DynmapCore/src/main/java/org/dynmap/common/chunk/DynmapChunk.java
@@ -0,0 +1,100 @@
+package org.dynmap.common.chunk;
+
+import java.util.Arrays;
+
+import org.dynmap.renderer.DynmapBlockState;
+import org.dynmap.common.BiomeMap;
+
+// Generic chunk representation
+public class DynmapChunk {
+	public final int cx, cz;	// Chunk coord (world coord / 16)
+	public final DynmapChunkSection[] sections;
+	public final int cy_min;	// CY value of first section in sections list (index = (Y >> 4) - cy_min
+	public final long inhabitedTicks;
+	
+	private DynmapChunk(int cx, int cz, int cy_min, DynmapChunkSection[] sections, long inhabTicks) {
+		this.cx = cx;
+		this.cz = cz;
+		this.inhabitedTicks = inhabTicks;
+		this.sections = new DynmapChunkSection[sections.length + 2];	// Add one empty at top and bottom
+		this.cy_min = cy_min - 1;	// Include empty at bottom
+		Arrays.fill(this.sections, DynmapChunkSection.EMPTY);	// Fill all spots with empty, including pad on bottom/top
+		for (int off = 0; off < sections.length; off++) {
+			if (sections[off] != null) {	// If defined, set the section
+				this.sections[off+1] = sections[off];
+			}
+		}
+	}
+	// Get section for given block Y coord
+	public final DynmapChunkSection getSection(int y) {
+		try {
+			return this.sections[(y >> 4) - cy_min];
+		} catch (IndexOutOfBoundsException ioobx) {	// Builder and padding should be avoiding this, but be safe
+			return DynmapChunkSection.EMPTY;
+		}
+	}
+	
+    public final DynmapBlockState getBlockType(int x, int y, int z) {    	
+    	return getSection(y).blocks.getBlock(x, y, z);
+    }
+
+    public final int getBlockSkyLight(int x, int y, int z) {
+    	return getSection(y).sky.getLight(x, y, z);
+    }
+
+    public final int getBlockEmittedLight(int x, int y, int z) {
+    	return getSection(y).emitted.getLight(x, y, z);
+    }
+
+    public final BiomeMap getBiome(int x, int y, int z) {
+    	return getSection(y).biomes.getBiome(x, y, z);
+    }
+
+    public final boolean isSectionEmpty(int sy) {
+    	return getSection(sy << 4).isEmpty;
+    }
+    
+    public final long getInhabitedTicks() {
+        return inhabitedTicks;
+    }	
+    // Builder for fabricating finalized chunk
+    public static class Builder {
+    	int x;
+    	int z;
+    	int y_min;
+    	DynmapChunkSection[] sections;
+    	long inhabTicks;
+    	
+    	public Builder(int world_ymin, int world_ymax) {
+    		reset(world_ymin, world_ymax);
+    	}
+    	public void reset(int world_ymin, int world_ymax) {
+    		x = 0; z = 0; 
+    		y_min = world_ymin >> 4;
+    		int y_max = (world_ymax + 15) >> 4;	// Round up
+    		sections = new DynmapChunkSection[y_max - y_min];	// Range for all potential sections
+    	}
+    	// Set inhabited ticks
+    	public Builder inhabitedTicks(long inh) {
+    		this.inhabTicks = inh;
+    		return this;
+    	}
+    	// Set section
+    	public Builder addSection(int sy, DynmapChunkSection sect) {
+    		if ((sy >= y_min) && ((sy - y_min) < sections.length)) {
+    			this.sections[sy - y_min] = sect;
+    		}
+    		return this;
+    	}
+    	// Set coordinates
+    	public Builder coords(int sx, int sz) {
+    		this.x = sx;
+    		this.z = sz;
+    		return this;
+    	}
+    	// Build chunk
+    	public DynmapChunk build() {
+    		return new DynmapChunk(x, z, y_min, sections, inhabTicks);
+    	}
+    }
+}
diff --git a/DynmapCore/src/main/java/org/dynmap/common/chunk/DynmapChunkSection.java b/DynmapCore/src/main/java/org/dynmap/common/chunk/DynmapChunkSection.java
index af09fd08..abe0b492 100644
--- a/DynmapCore/src/main/java/org/dynmap/common/chunk/DynmapChunkSection.java
+++ b/DynmapCore/src/main/java/org/dynmap/common/chunk/DynmapChunkSection.java
@@ -131,6 +131,10 @@ public class DynmapChunkSection {
 	private static BlockStateAccess defaultBlockState = new BlockStateAccessSingle(DynmapBlockState.AIR);
 	private static LightingAccess defaultSky = new LightingAccessSingle(15);
 	private static LightingAccess defaultEmit = new LightingAccessSingle(0);
+	
+	// Shared default empty section
+	public static final DynmapChunkSection EMPTY = new DynmapChunkSection(defaultBlockState, defaultBiome, defaultSky, defaultEmit, true);
+	
 	// Factory for building section
 	public static class Builder {
 		private BiomeAccess ba;