Leaf/leaf-server/minecraft-patches/features/0184-optimise-getBiome.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: hayanesuru <hayanesuru@outlook.jp>
Date: Tue, 3 Jun 2025 15:20:40 +0900
Subject: [PATCH] optimise getBiome


diff --git a/net/minecraft/server/level/ServerLevel.java b/net/minecraft/server/level/ServerLevel.java
index eb849c57992658005e0f514c6f7923f8ca43bebf..c706f0dacd9c322d9b09d6ee073872c4229818b0 100644
--- a/net/minecraft/server/level/ServerLevel.java
+++ b/net/minecraft/server/level/ServerLevel.java
@@ -899,6 +899,7 @@ public class ServerLevel extends Level implements ServerEntityGetter, WorldGenLe
             this.advanceWeatherCycle();
         }
 
+        if (runsNormally && (getGameTime() & 7L) == 7L) this.getBiomeManager().recomputeCache(); // Leaf - cache getBiome
         // Leaf start - SparklyPaper - parallel world ticking
         if (!org.dreeam.leaf.config.modules.async.SparklyPaperParallelWorldTicking.enabled) {
             this.moonrise$midTickTasks();
diff --git a/net/minecraft/world/level/biome/BiomeManager.java b/net/minecraft/world/level/biome/BiomeManager.java
index a48175a7ebb1788ace46395621ed78d910178a53..2ce1754e0cf854468791688752a7d16c76917d3b 100644
--- a/net/minecraft/world/level/biome/BiomeManager.java
+++ b/net/minecraft/world/level/biome/BiomeManager.java
@@ -15,6 +15,10 @@ public class BiomeManager {
     private final BiomeManager.NoiseBiomeSource noiseBiomeSource;
     private final long biomeZoomSeed;
     private static final double maxOffset = 0.4500000001D; // Leaf - Carpet-Fixes - Optimized getBiome method
+    // Leaf start - cache getBiome
+    private final Holder<Biome>[] biomeCache = new Holder[65536];
+    private final long[] biomeCachePos = new long[65536];
+    // Leaf end - cache getBiome
 
     public BiomeManager(BiomeManager.NoiseBiomeSource noiseBiomeSource, long biomeZoomSeed) {
         this.noiseBiomeSource = noiseBiomeSource;
@@ -29,7 +33,28 @@ public class BiomeManager {
         return new BiomeManager(newSource, this.biomeZoomSeed);
     }
 
+    // Leaf start - cache getBiome
+    public synchronized void recomputeCache() {
+        java.util.Arrays.fill(this.biomeCache, null);
+    }
+    // Leaf end - cache getBiome
+
     public Holder<Biome> getBiome(BlockPos pos) {
+        // Leaf start - cache getBiome
+        long packedPos = pos.asLong();
+        long hash = packedPos;
+        hash = (hash ^ (hash >>> 32)) * 0xff51afd7ed558ccdL;
+        hash = (hash ^ (hash >>> 32)) * 0xc4ceb9fe1a85ec53L;
+        hash = (hash ^ (hash >>> 32)) & 65535L;
+        synchronized (this) {
+            if (biomeCachePos[(int) hash] == packedPos) {
+                Holder<Biome> biome = biomeCache[(int) hash];
+                if (biome != null) {
+                    return biome;
+                }
+            }
+        }
+        // Leaf end - cache getBiome
         // Leaf start - Carpet-Fixes - Optimized getBiome method
         int xMinus2 = pos.getX() - 2;
         int yMinus2 = pos.getY() - 2;
@@ -85,11 +110,18 @@ public class BiomeManager {
                 smallestDist = biomeDist;
             }
         }
-        return this.noiseBiomeSource.getNoiseBiome(
+        // Leaf start - cache getBiome
+        Holder<Biome> biome = this.noiseBiomeSource.getNoiseBiome(
             (smallestX & 4) == 0 ? x : x + 1,
             (smallestX & 2) == 0 ? y : y + 1,
             (smallestX & 1) == 0 ? z : z + 1
         );
+        synchronized (this) {
+            biomeCache[(int) hash] = biome;
+            biomeCachePos[(int) hash] = packedPos;
+        }
+        return biome;
+        // Leaf end - cache getBiome
         // Leaf end - Carpet-Fixes - Optimized getBiome method
     }
 
@@ -126,9 +158,18 @@ public class BiomeManager {
         return Mth.square(zNoise + fiddle2) + Mth.square(yNoise + fiddle1) + Mth.square(xNoise + fiddle);
     }
 
+    // Leaf start
+    private static final double[] FIDDLE_TABLE = new double[1024];
+    static {
+        for (int i = 0; i < 1024; i++) {
+            FIDDLE_TABLE[i] = (i - 512) * (0.9 / 1024.0);
+        }
+    }
     private static double getFiddle(long seed) {
-        return (double)(((seed >> 24) & (1024 - 1)) - (1024/2)) * (0.9 / 1024.0); // Paper - avoid floorMod, fp division, and fp subtraction
+        return FIDDLE_TABLE[(int)(seed >>> 24) & 1023];
+        // return (double)(((seed >> 24) & (1024 - 1)) - (1024/2)) * (0.9 / 1024.0); // Paper - avoid floorMod, fp division, and fp subtraction
     }
+    // Leaf end
 
     public interface NoiseBiomeSource {
         Holder<Biome> getNoiseBiome(int x, int y, int z);