From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Nassim Jahnke <jahnke.nassim@gmail.com>
Date: Tue, 31 Aug 2021 17:05:27 +0200
Subject: [PATCH] Configurable feature seeds

Co-authored-by: Thonk <30448663+ExcessiveAmountsOfZombies@users.noreply.github.com>

diff --git a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
index 4ae21ba5d04c954592ec4f85d43ff71ec7dadea1..bee97b02227ef198c79c48b43610fb417435a2d2 100644
--- a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
+++ b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
@@ -922,6 +922,37 @@ public class PaperWorldConfig {
         return table;
     }
 
+    public it.unimi.dsi.fastutil.objects.Object2LongOpenHashMap<net.minecraft.resources.ResourceLocation> featureSeeds = new it.unimi.dsi.fastutil.objects.Object2LongOpenHashMap<>();
+    private void featureSeeds() {
+        featureSeeds.defaultReturnValue(-1);
+        final boolean randomise = getBoolean("feature-seeds.generate-random-seeds-for-all", false);
+        ConfigurationSection section = config.getConfigurationSection("world-settings." + worldName + ".feature-seeds");
+        if (section == null) {
+            section = config.getConfigurationSection("world-settings.default.feature-seeds");
+        }
+        for (final String key : section.getKeys(false)) {
+            net.minecraft.resources.ResourceLocation resourceKey = new net.minecraft.resources.ResourceLocation(key);
+            featureSeeds.put(resourceKey, section.getLong(key));
+        }
+        if (randomise) {
+            final Map<String, Object> randomisedSeeds = new HashMap<>();
+            final java.util.Random random = new java.util.Random();
+            for (net.minecraft.resources.ResourceLocation resourceLocation : net.minecraft.server.MinecraftServer.getServer()
+                .registryAccess().registryOrThrow(net.minecraft.core.Registry.CONFIGURED_FEATURE_REGISTRY).keySet()) {
+                if (featureSeeds.containsKey(resourceLocation)) {
+                    continue;
+                }
+
+                final long seed = random.nextLong();
+                randomisedSeeds.put("world-settings." + worldName + ".feature-seeds." + resourceLocation.getPath(), seed);
+                featureSeeds.put(resourceLocation, seed);
+            }
+            if (!randomisedSeeds.isEmpty()) {
+                config.addDefaults(randomisedSeeds);
+            }
+        }
+    }
+
     public int getBehaviorTickRate(String typeName, String entityType, int def) {
         return getIntOrDefault(behaviorTickRates, typeName, entityType, def);
     }
diff --git a/src/main/java/net/minecraft/world/level/biome/Biome.java b/src/main/java/net/minecraft/world/level/biome/Biome.java
index 0ea6fedf6e660bc133fd5eb34d3d9bac3e581f32..b5c6b0bc307aef2835761cfa50413cebfd624795 100644
--- a/src/main/java/net/minecraft/world/level/biome/Biome.java
+++ b/src/main/java/net/minecraft/world/level/biome/Biome.java
@@ -225,7 +225,7 @@ public final class Biome {
 
     public void generate(StructureFeatureManager structureAccessor, ChunkGenerator chunkGenerator, WorldGenRegion region, long populationSeed, WorldgenRandom random, BlockPos origin) {
         List<List<Supplier<ConfiguredFeature<?, ?>>>> list = this.generationSettings.features();
-        Registry<ConfiguredFeature<?, ?>> registry = region.registryAccess().registryOrThrow(Registry.CONFIGURED_FEATURE_REGISTRY);
+        Registry<ConfiguredFeature<?, ?>> registry = region.registryAccess().registryOrThrow(Registry.CONFIGURED_FEATURE_REGISTRY); // Paper - diff on change
         Registry<StructureFeature<?>> registry2 = region.registryAccess().registryOrThrow(Registry.STRUCTURE_FEATURE_REGISTRY);
         int i = GenerationStep.Decoration.values().length;
 
@@ -267,7 +267,16 @@ public final class Biome {
                     Supplier<String> supplier3 = () -> {
                         return registry.getResourceKey(configuredFeature).map(Object::toString).orElseGet(configuredFeature::toString);
                     };
-                    random.setFeatureSeed(populationSeed, k, j);
+                    // Paper start - change populationSeed used in random
+                    long featurePopulationSeed = populationSeed;
+                    final ResourceLocation location = registry.getKey(configuredFeature);
+                    final long configFeatureSeed = region.getMinecraftWorld().paperConfig.featureSeeds.getLong(location);
+                    if (configFeatureSeed != -1) {
+                        final ChunkPos center = region.getCenter();
+                        featurePopulationSeed = random.setDecorationSeed(configFeatureSeed, center.getMinBlockX(), center.getMinBlockZ()); // See ChunkGenerator#addVanillaDecorations
+                    }
+                    random.setFeatureSeed(featurePopulationSeed, k, j);
+                    // Paper end
 
                     try {
                         region.setCurrentlyGenerating(supplier3);