From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: violetc <58360096+s-yh-china@users.noreply.github.com>
Date: Tue, 18 Jul 2023 13:36:25 +0800
Subject: [PATCH] Optimize world generation chunk and block access

This patch is Powered by Gale(https://github.com/GaleMC/Gale)

diff --git a/src/main/java/net/minecraft/server/level/WorldGenRegion.java b/src/main/java/net/minecraft/server/level/WorldGenRegion.java
index a6c31a558794a6e626e83176a1cbe78b6bd90f6e..4a4b8ea0e8ba89d5a5ad890493d525a0f2a596fc 100644
--- a/src/main/java/net/minecraft/server/level/WorldGenRegion.java
+++ b/src/main/java/net/minecraft/server/level/WorldGenRegion.java
@@ -86,6 +86,10 @@ public class WorldGenRegion implements WorldGenLevel {
     private Supplier<String> currentlyGenerating;
     private final AtomicLong subTickCount = new AtomicLong();
     private static final ResourceLocation WORLDGEN_REGION_RANDOM = new ResourceLocation("worldgen_region_random");
+    // Leaves start - optimize world generation chunk and block access
+    private ChunkAccess[] chunksArr;
+    private int minChunkX, minChunkZ;
+    // Leaves end - optimize world generation chunk and block access
 
     public WorldGenRegion(ServerLevel world, List<ChunkAccess> chunks, ChunkStatus status, int placementRadius) {
         this.generatingStatus = status;
@@ -107,6 +111,11 @@ public class WorldGenRegion implements WorldGenLevel {
             this.firstPos = ((ChunkAccess) chunks.get(0)).getPos();
             this.lastPos = ((ChunkAccess) chunks.get(chunks.size() - 1)).getPos();
         }
+        // Leaves start - optimize world generation chunk and block access
+        this.minChunkX = this.firstPos.x;
+        this.minChunkZ = this.firstPos.z;
+        this.chunksArr = chunks.toArray(new ChunkAccess[0]);
+        // Leaves end - optimize world generation chunk and block access
     }
 
     // Paper start - starlight
@@ -145,8 +154,29 @@ public class WorldGenRegion implements WorldGenLevel {
 
     @Override
     public ChunkAccess getChunk(int chunkX, int chunkZ) {
-        return this.getChunk(chunkX, chunkZ, ChunkStatus.EMPTY);
+        // Leaves start - optimize world generation chunk and block access
+        if (!org.leavesmc.leaves.LeavesConfig.optimizeWorldGenerationAccess) {
+            return this.getChunk(chunkX, chunkZ, ChunkStatus.EMPTY);
+        } else {
+            int x = chunkX - this.minChunkX;
+            int z = chunkZ - this.minChunkZ;
+            int w = this.size;
+
+            if (x >= 0 && z >= 0 && x < w && z < w) {
+                return this.chunksArr[x + z * w];
+            } else {
+                throw new NullPointerException("No chunk exists at " + new ChunkPos(chunkX, chunkZ));
+            }
+        }
+        // Leaves end - optimize world generation chunk and block access
+    }
+
+    // Leaves start - optimize world generation chunk and block access
+    public ChunkAccess getChunk(BlockPos pos) {
+        // Skip checking chunk.getStatus().isAtLeast(ChunkStatus.EMPTY) here, because it is always true
+        return this.getChunk(SectionPos.blockToSectionCoord(pos.getX()), SectionPos.blockToSectionCoord(pos.getZ()));
     }
+    // Leaves end - optimize world generation chunk and block access
 
     @Nullable
     @Override
@@ -211,7 +241,21 @@ public class WorldGenRegion implements WorldGenLevel {
 
     @Override
     public BlockState getBlockState(BlockPos pos) {
-        return this.getChunk(SectionPos.blockToSectionCoord(pos.getX()), SectionPos.blockToSectionCoord(pos.getZ())).getBlockState(pos);
+        // Leaves start - optimize world generation chunk and block access
+        if (!org.leavesmc.leaves.LeavesConfig.optimizeWorldGenerationAccess) {
+            return this.getChunk(SectionPos.blockToSectionCoord(pos.getX()), SectionPos.blockToSectionCoord(pos.getZ())).getBlockState(pos);
+        } else {
+            int x = SectionPos.blockToSectionCoord(pos.getX()) - this.minChunkX;
+            int z = SectionPos.blockToSectionCoord(pos.getZ()) - this.minChunkZ;
+            int w = this.size;
+
+            if (x >= 0 && z >= 0 && x < w && z < w) {
+                return this.chunksArr[x + z * w].getBlockState(pos);
+            } else {
+                throw new NullPointerException("No chunk exists at " + new ChunkPos(pos));
+            }
+        }
+        // Leaves end - optimize world generation chunk and block access
     }
 
     @Override