From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: MiniDigger <admin@minidigger.me>
Date: Wed, 29 Apr 2020 02:10:32 +0200
Subject: [PATCH] Allow delegation to vanilla chunk gen


diff --git a/src/main/java/org/bukkit/craftbukkit/CraftServer.java b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
index b1dfd1b13652807882e057ae4fb55f9a045d1a16..926ecc79744142c1361399afa61719db435638fa 100644
--- a/src/main/java/org/bukkit/craftbukkit/CraftServer.java
+++ b/src/main/java/org/bukkit/craftbukkit/CraftServer.java
@@ -2244,6 +2244,32 @@ public final class CraftServer implements Server {
         return new OldCraftChunkData(world.getMinHeight(), world.getMaxHeight(), handle.registryAccess().registryOrThrow(Registry.BIOME_REGISTRY));
     }
 
+    // Paper start
+    @Override
+    public ChunkGenerator.ChunkData createVanillaChunkData(World world, int x, int z) {
+        // get empty object
+        OldCraftChunkData data = (OldCraftChunkData) createChunkData(world);
+        // do bunch of vanilla shit
+        net.minecraft.server.level.ServerLevel nmsWorld = ((CraftWorld) world).getHandle();
+        net.minecraft.world.level.chunk.ProtoChunk protoChunk = new net.minecraft.world.level.chunk.ProtoChunk(new net.minecraft.world.level.ChunkPos(x, z), null, nmsWorld, nmsWorld);
+        List<net.minecraft.world.level.chunk.ChunkAccess> list = new ArrayList<>();
+        list.add(protoChunk);
+        net.minecraft.server.level.WorldGenRegion genRegion = new net.minecraft.server.level.WorldGenRegion(nmsWorld, list, net.minecraft.world.level.chunk.ChunkStatus.EMPTY, -1);
+        // call vanilla generator, one feature after another. Order here is important!
+        net.minecraft.world.level.chunk.ChunkGenerator chunkGenerator = nmsWorld.getChunkSource().generator;
+        if (chunkGenerator instanceof org.bukkit.craftbukkit.generator.CustomChunkGenerator) {
+            chunkGenerator = ((org.bukkit.craftbukkit.generator.CustomChunkGenerator) chunkGenerator).delegate;
+        }
+        chunkGenerator.createBiomes(nmsWorld.registryAccess().registryOrThrow(Registry.BIOME_REGISTRY), protoChunk);
+        chunkGenerator.fillFromNoise((runnable) -> {}, nmsWorld.structureFeatureManager(), protoChunk);
+        chunkGenerator.buildSurfaceAndBedrock(genRegion, protoChunk);
+        // copy over generated sections
+        data.setRawChunkData(protoChunk.getSections());
+        // hooray!
+        return data;
+    }
+    // Paper end
+
     @Override
     public BossBar createBossBar(String title, BarColor color, BarStyle style, BarFlag... flags) {
         return new CraftBossBar(title, color, style, flags);
diff --git a/src/main/java/org/bukkit/craftbukkit/generator/OldCraftChunkData.java b/src/main/java/org/bukkit/craftbukkit/generator/OldCraftChunkData.java
index 960405935e395a31c0300773c41413801cf0d290..f86a8619862c752ca5d47a2ce4c2d0fab6f0810d 100644
--- a/src/main/java/org/bukkit/craftbukkit/generator/OldCraftChunkData.java
+++ b/src/main/java/org/bukkit/craftbukkit/generator/OldCraftChunkData.java
@@ -23,7 +23,7 @@ import org.bukkit.material.MaterialData;
 public final class OldCraftChunkData implements ChunkGenerator.ChunkData {
     private final int minHeight;
     private final int maxHeight;
-    private final LevelChunkSection[] sections;
+    private LevelChunkSection[] sections;
     private final Registry<net.minecraft.world.level.biome.Biome> biomes;
     private Set<BlockPos> tiles;
     private final Set<BlockPos> lights = new HashSet<>();
@@ -192,4 +192,10 @@ public final class OldCraftChunkData implements ChunkGenerator.ChunkData {
     Set<BlockPos> getLights() {
         return this.lights;
     }
+
+    // Paper start
+    public void setRawChunkData(LevelChunkSection[] sections) {
+        this.sections = sections;
+    }
+    // Paper end
 }