Paper/patches/server/0794-Expose-vanilla-BiomeProvider-from-WorldInfo.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Jason Penilla <11360596+jpenilla@users.noreply.github.com>
Date: Thu, 6 Jan 2022 15:59:06 -0800
Subject: [PATCH] Expose vanilla BiomeProvider from WorldInfo


diff --git a/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
index ce99c2f4f172baa96831b194b4289da02a244519..efe7a3afaf5ef548bded4dc2957375fdbc605d63 100644
--- a/src/main/java/net/minecraft/server/MinecraftServer.java
+++ b/src/main/java/net/minecraft/server/MinecraftServer.java
@@ -562,7 +562,7 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
             }
             // Paper end
 
-            org.bukkit.generator.WorldInfo worldInfo = new org.bukkit.craftbukkit.generator.CraftWorldInfo(iworlddataserver, worldSession, org.bukkit.World.Environment.getEnvironment(dimension), worlddimension.typeHolder().value());
+            org.bukkit.generator.WorldInfo worldInfo = new org.bukkit.craftbukkit.generator.CraftWorldInfo(iworlddataserver, worldSession, org.bukkit.World.Environment.getEnvironment(dimension), worlddimension.typeHolder().value(), worlddimension.generator(), this.registryAccess()); // Paper
             if (biomeProvider == null && gen != null) {
                 biomeProvider = gen.getDefaultBiomeProvider(worldInfo);
             }
diff --git a/src/main/java/org/bukkit/craftbukkit/CraftServer.java b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
index bf747c7584733014aac771ba4ca039c588582f25..e69480421f4fbebcf2a2000e8fa91fc9a9d34201 100644
--- a/src/main/java/org/bukkit/craftbukkit/CraftServer.java
+++ b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
@@ -1212,7 +1212,7 @@ public final class CraftServer implements Server {
         net.minecraft.core.Registry<LevelStem> iregistry = worlddata.worldGenSettings().dimensions();
         LevelStem worlddimension = (LevelStem) iregistry.get(actualDimension);
 
-        WorldInfo worldInfo = new CraftWorldInfo(worlddata, worldSession, creator.environment(), worlddimension.typeHolder().value());
+        WorldInfo worldInfo = new CraftWorldInfo(worlddata, worldSession, creator.environment(), worlddimension.typeHolder().value(), worlddimension.generator(), this.getHandle().getServer().registryAccess()); // Paper
         if (biomeProvider == null && generator != null) {
             biomeProvider = generator.getDefaultBiomeProvider(worldInfo);
         }
diff --git a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
index 65c82c3ec11b29245f7d92e402f2cf2ab5b8dae4..36a8552f046f8f6bf8138bef4ff0c526425e57a4 100644
--- a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
+++ b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
@@ -200,6 +200,30 @@ public class CraftWorld extends CraftRegionAccessor implements World {
     public int getPlayerCount() {
         return world.players().size();
     }
+
+    @Override
+    public BiomeProvider vanillaBiomeProvider() {
+        net.minecraft.server.level.ServerChunkCache serverCache = this.getHandle().chunkSource;
+
+        final net.minecraft.world.level.biome.BiomeSource biomeSource = serverCache.getGenerator().getBiomeSource();
+        final net.minecraft.world.level.biome.Climate.Sampler sampler = serverCache.randomState().sampler();
+        final net.minecraft.core.Registry<net.minecraft.world.level.biome.Biome> biomeRegistry = this.getHandle().registryAccess().registryOrThrow(net.minecraft.core.Registry.BIOME_REGISTRY);
+
+        final List<Biome> possibleBiomes = biomeSource.possibleBiomes().stream()
+            .map(biome -> CraftBlock.biomeBaseToBiome(biomeRegistry, biome))
+            .toList();
+        return new BiomeProvider() {
+            @Override
+            public Biome getBiome(final org.bukkit.generator.WorldInfo worldInfo, final int x, final int y, final int z) {
+                return CraftBlock.biomeBaseToBiome(biomeRegistry, biomeSource.getNoiseBiome(x >> 2, y >> 2, z >> 2, sampler));
+            }
+
+            @Override
+            public List<Biome> getBiomes(final org.bukkit.generator.WorldInfo worldInfo) {
+                return possibleBiomes;
+            }
+        };
+    }
     // Paper end
 
     private static final Random rand = new Random();
diff --git a/src/main/java/org/bukkit/craftbukkit/generator/CraftWorldInfo.java b/src/main/java/org/bukkit/craftbukkit/generator/CraftWorldInfo.java
index 3795dc9b12d62113146e803554283acd8d0e5db9..b9af0c68bfa877314de0d45741a54795b581d9b8 100644
--- a/src/main/java/org/bukkit/craftbukkit/generator/CraftWorldInfo.java
+++ b/src/main/java/org/bukkit/craftbukkit/generator/CraftWorldInfo.java
@@ -17,8 +17,14 @@ public class CraftWorldInfo implements WorldInfo {
     private final long seed;
     private final int minHeight;
     private final int maxHeight;
+    // Paper start
+    private final net.minecraft.world.level.chunk.ChunkGenerator vanillaChunkGenerator;
+    private final net.minecraft.core.RegistryAccess.Frozen registryAccess;
 
-    public CraftWorldInfo(ServerLevelData worldDataServer, LevelStorageSource.LevelStorageAccess session, World.Environment environment, DimensionType dimensionManager) {
+    public CraftWorldInfo(ServerLevelData worldDataServer, LevelStorageSource.LevelStorageAccess session, World.Environment environment, DimensionType dimensionManager, net.minecraft.world.level.chunk.ChunkGenerator chunkGenerator, net.minecraft.core.RegistryAccess.Frozen registryAccess) {
+        this.registryAccess = registryAccess;
+        this.vanillaChunkGenerator = chunkGenerator;
+        // Paper end
         this.name = worldDataServer.getLevelName();
         this.uuid = WorldUUID.getUUID(session.levelDirectory.path().toFile());
         this.environment = environment;
@@ -27,15 +33,6 @@ public class CraftWorldInfo implements WorldInfo {
         this.maxHeight = dimensionManager.minY() + dimensionManager.height();
     }
 
-    public CraftWorldInfo(String name, UUID uuid, World.Environment environment, long seed, int minHeight, int maxHeight) {
-        this.name = name;
-        this.uuid = uuid;
-        this.environment = environment;
-        this.seed = seed;
-        this.minHeight = minHeight;
-        this.maxHeight = maxHeight;
-    }
-
     @Override
     public String getName() {
         return this.name;
@@ -65,4 +62,35 @@ public class CraftWorldInfo implements WorldInfo {
     public int getMaxHeight() {
         return this.maxHeight;
     }
+
+    // Paper start
+    @Override
+    public org.bukkit.generator.BiomeProvider vanillaBiomeProvider() {
+        final net.minecraft.world.level.levelgen.RandomState randomState;
+        if (vanillaChunkGenerator instanceof net.minecraft.world.level.levelgen.NoiseBasedChunkGenerator noiseBasedChunkGenerator) {
+            randomState = net.minecraft.world.level.levelgen.RandomState.create(noiseBasedChunkGenerator.generatorSettings().value(),
+                registryAccess.registryOrThrow(net.minecraft.core.Registry.NOISE_REGISTRY), getSeed());
+        } else {
+            randomState = net.minecraft.world.level.levelgen.RandomState.create(net.minecraft.world.level.levelgen.NoiseGeneratorSettings.dummy(),
+                registryAccess.registryOrThrow(net.minecraft.core.Registry.NOISE_REGISTRY), getSeed());
+        }
+
+        final net.minecraft.core.Registry<net.minecraft.world.level.biome.Biome> biomeRegistry = CraftWorldInfo.this.registryAccess.registryOrThrow(net.minecraft.core.Registry.BIOME_REGISTRY);
+        final java.util.List<org.bukkit.block.Biome> possibleBiomes = CraftWorldInfo.this.vanillaChunkGenerator.getBiomeSource().possibleBiomes().stream()
+            .map(biome -> org.bukkit.craftbukkit.block.CraftBlock.biomeBaseToBiome(biomeRegistry, biome))
+            .toList();
+        return new org.bukkit.generator.BiomeProvider() {
+            @Override
+            public org.bukkit.block.Biome getBiome(final WorldInfo worldInfo, final int x, final int y, final int z) {
+                return org.bukkit.craftbukkit.block.CraftBlock.biomeBaseToBiome(biomeRegistry,
+                    CraftWorldInfo.this.vanillaChunkGenerator.getBiomeSource().getNoiseBiome(x >> 2, y >> 2, z >> 2, randomState.sampler()));
+            }
+
+            @Override
+            public java.util.List<org.bukkit.block.Biome> getBiomes(final org.bukkit.generator.WorldInfo worldInfo) {
+                return possibleBiomes;
+            }
+        };
+    }
+    // Paper end
 }