[1.19.x] Add stock biome modifier types for adding features and spawns (#8697)

src/main/java/net/minecraftforge/common/ForgeMod.java

@@ -20,10 +20,16 @@ import net.minecraft.world.entity.item.ItemEntity;
 import net.minecraft.world.item.crafting.Ingredient;
 import net.minecraft.world.level.BlockAndTintGetter;
 import net.minecraft.world.level.BlockGetter;
+import net.minecraft.world.level.biome.Biome;
+import net.minecraft.world.level.biome.MobSpawnSettings.SpawnerData;
+import net.minecraft.world.level.levelgen.GenerationStep.Decoration;
+import net.minecraft.world.level.levelgen.placement.PlacedFeature;
 import net.minecraft.world.level.material.Fluid;
 import net.minecraft.world.item.Items;
 import net.minecraft.sounds.SoundEvent;
+import net.minecraft.util.ExtraCodecs;
 import net.minecraft.core.Registry;
+import net.minecraft.core.RegistryCodecs;
 import net.minecraft.world.level.material.FluidState;
 import net.minecraft.world.level.pathfinder.BlockPathTypes;
 import net.minecraft.world.phys.Vec3;
@@ -42,6 +48,10 @@ import net.minecraftforge.common.extensions.IForgePlayer;
 import net.minecraftforge.common.loot.CanToolPerformAction;
 import net.minecraftforge.common.loot.LootTableIdCondition;
 import net.minecraftforge.common.world.BiomeModifier;
+import net.minecraftforge.common.world.ForgeBiomeModifiers.AddFeaturesBiomeModifier;
+import net.minecraftforge.common.world.ForgeBiomeModifiers.AddSpawnsBiomeModifier;
+import net.minecraftforge.common.world.ForgeBiomeModifiers.RemoveFeaturesBiomeModifier;
+import net.minecraftforge.common.world.ForgeBiomeModifiers.RemoveSpawnsBiomeModifier;
 import net.minecraftforge.common.world.NoneBiomeModifier;
 import net.minecraftforge.common.world.NoneStructureModifier;
 import net.minecraftforge.common.world.StructureModifier;
@@ -92,11 +102,14 @@ import net.minecraftforge.fml.common.Mod;
 import org.apache.logging.log4j.Marker;
 import org.apache.logging.log4j.MarkerManager;
 
+import com.mojang.datafixers.util.Either;
 import com.mojang.serialization.Codec;
+import com.mojang.serialization.codecs.RecordCodecBuilder;
 import org.jetbrains.annotations.Nullable;
 
 import java.util.*;
 import java.util.function.Consumer;
+import java.util.function.Function;
 
 @Mod("forge")
 public class ForgeMod
@@ -147,6 +160,55 @@ public class ForgeMod
      */
     public static final RegistryObject<Codec<NoneBiomeModifier>> NONE_BIOME_MODIFIER_TYPE = BIOME_MODIFIER_SERIALIZERS.register("none", () -> Codec.unit(NoneBiomeModifier.INSTANCE));
 
+    /**
+     * Stock biome modifier for adding features to biomes.
+     */
+    public static final RegistryObject<Codec<AddFeaturesBiomeModifier>> ADD_FEATURES_BIOME_MODIFIER_TYPE = BIOME_MODIFIER_SERIALIZERS.register("add_features", () ->
+        RecordCodecBuilder.create(builder -> builder.group(
+                Biome.LIST_CODEC.fieldOf("biomes").forGetter(AddFeaturesBiomeModifier::biomes),
+                PlacedFeature.LIST_CODEC.fieldOf("features").forGetter(AddFeaturesBiomeModifier::features),
+                Decoration.CODEC.fieldOf("step").forGetter(AddFeaturesBiomeModifier::step)
+            ).apply(builder, AddFeaturesBiomeModifier::new))
+        );
+    
+    /**
+     * Stock biome modifier for removing features from biomes.
+     */
+    public static final RegistryObject<Codec<RemoveFeaturesBiomeModifier>> REMOVE_FEATURES_BIOME_MODIFIER_TYPE = BIOME_MODIFIER_SERIALIZERS.register("remove_features", () ->
+        RecordCodecBuilder.create(builder -> builder.group(
+                Biome.LIST_CODEC.fieldOf("biomes").forGetter(RemoveFeaturesBiomeModifier::biomes),
+                PlacedFeature.LIST_CODEC.fieldOf("features").forGetter(RemoveFeaturesBiomeModifier::features),
+                new ExtraCodecs.EitherCodec<List<Decoration>, Decoration>(Decoration.CODEC.listOf(), Decoration.CODEC).<Set<Decoration>>xmap(
+                        either -> either.map(Set::copyOf, Set::of), // convert list/singleton to set when decoding
+                        set -> set.size() == 1 ? Either.right(set.toArray(Decoration[]::new)[0]) : Either.left(List.copyOf(set))
+                    ).optionalFieldOf("steps", EnumSet.allOf(Decoration.class)).forGetter(RemoveFeaturesBiomeModifier::steps)
+            ).apply(builder, RemoveFeaturesBiomeModifier::new))
+        );
+    
+    /**
+     * Stock biome modifier for adding mob spawns to biomes.
+     */
+    public static final RegistryObject<Codec<AddSpawnsBiomeModifier>> ADD_SPAWNS_BIOME_MODIFIER_TYPE = BIOME_MODIFIER_SERIALIZERS.register("add_spawns", () ->
+        RecordCodecBuilder.create(builder -> builder.group(
+                Biome.LIST_CODEC.fieldOf("biomes").forGetter(AddSpawnsBiomeModifier::biomes),
+                // Allow either a list or single spawner, attempting to decode the list format first.
+                // Uses the better EitherCodec that logs both errors if both formats fail to parse.
+                new ExtraCodecs.EitherCodec<>(SpawnerData.CODEC.listOf(), SpawnerData.CODEC).xmap(
+                        either -> either.map(Function.identity(), List::of), // convert list/singleton to list when decoding
+                        list -> list.size() == 1 ? Either.right(list.get(0)) : Either.left(list) // convert list to singleton/list when encoding
+                    ).fieldOf("spawners").forGetter(AddSpawnsBiomeModifier::spawners)
+            ).apply(builder, AddSpawnsBiomeModifier::new))
+        );
+    
+    /**
+     * Stock biome modifier for removing mob spawns from biomes.
+     */
+    public static final RegistryObject<Codec<RemoveSpawnsBiomeModifier>> REMOVE_SPAWNS_BIOME_MODIFIER_TYPE = BIOME_MODIFIER_SERIALIZERS.register("remove_spawns", () ->
+        RecordCodecBuilder.create(builder -> builder.group(
+                Biome.LIST_CODEC.fieldOf("biomes").forGetter(RemoveSpawnsBiomeModifier::biomes),
+                RegistryCodecs.homogeneousList(ForgeRegistries.Keys.ENTITY_TYPES).fieldOf("entity_types").forGetter(RemoveSpawnsBiomeModifier::entityTypes)
+            ).apply(builder, RemoveSpawnsBiomeModifier::new))
+        );
     /**
      * Noop structure modifier. Can be used in a structure modifier json with "type": "forge:none".
      */

src/main/java/net/minecraftforge/common/data/JsonCodecProvider.java

@@ -39,7 +39,7 @@ import org.slf4j.Logger;
  *
  * @param <T> the type of thing being generated.
  */
-public final class JsonCodecProvider<T> implements DataProvider
+public class JsonCodecProvider<T> implements DataProvider
 {
     private static final Logger LOGGER = LogUtils.getLogger();
     protected final DataGenerator dataGenerator;

src/main/java/net/minecraftforge/common/world/ForgeBiomeModifiers.java

@@ -0,0 +1,220 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+
+package net.minecraftforge.common.world;
+
+import java.util.EnumSet;
+import java.util.List;
+import java.util.Set;
+
+import com.mojang.serialization.Codec;
+
+import net.minecraft.core.Holder;
+import net.minecraft.core.HolderSet;
+import net.minecraft.world.entity.EntityType;
+import net.minecraft.world.entity.MobCategory;
+import net.minecraft.world.level.biome.Biome;
+import net.minecraft.world.level.biome.MobSpawnSettings.SpawnerData;
+import net.minecraft.world.level.levelgen.GenerationStep.Decoration;
+import net.minecraft.world.level.levelgen.placement.PlacedFeature;
+import net.minecraftforge.common.ForgeMod;
+import net.minecraftforge.common.world.ModifiableBiomeInfo.BiomeInfo.Builder;
+import net.minecraftforge.registries.ForgeRegistries;
+
+public final class ForgeBiomeModifiers
+{
+    private ForgeBiomeModifiers() {} // Utility class.
+    
+    /**
+     * <p>Stock biome modifier that adds features to biomes. Has the following json format:</p>
+     * <pre>
+     * {
+     *   "type": "forge:add_features", // required
+     *   "biomes": "#namespace:your_biome_tag" // accepts a biome id, [list of biome ids], or #namespace:biome_tag
+     *   "features": "namespace:your_feature", // accepts a placed feature id, [list of placed feature ids], or #namespace:feature_tag
+     *   "step": "underground_ores" // accepts a Decoration enum name
+     * }
+     * </pre>
+     * <p>Be wary of using this to add vanilla PlacedFeatures to biomes, as doing so may cause a feature cycle violation.</p>
+     * 
+     * @param biomes Biomes to add features to.
+     * @param features PlacedFeatures to add to biomes.
+     * @param step Decoration step to run features in.
+     */
+    public static record AddFeaturesBiomeModifier(HolderSet<Biome> biomes, HolderSet<PlacedFeature> features, Decoration step) implements BiomeModifier
+    {
+        @Override
+        public void modify(Holder<Biome> biome, Phase phase, Builder builder)
+        {
+            if (phase == Phase.ADD && this.biomes.contains(biome))
+            {
+                BiomeGenerationSettingsBuilder generationSettings = builder.getGenerationSettings();
+                this.features.forEach(holder -> generationSettings.addFeature(this.step, holder));
+            }
+        }
+
+        @Override
+        public Codec<? extends BiomeModifier> codec()
+        {
+            return ForgeMod.ADD_FEATURES_BIOME_MODIFIER_TYPE.get();
+        }
+    }
+
+    
+    /**
+     * <p>Stock biome modifier that removes features from biomes. Has the following json format:</p>
+     * <pre>
+     * {
+     *   "type": "forge:removefeatures", // required
+     *   "biomes": "#namespace:your_biome_tag", // accepts a biome id, [list of biome ids], or #namespace:biome_tag
+     *   "features": "namespace:your_feature", // accepts a placed feature id, [list of placed feature ids], or #namespace:feature_tag
+     *   "steps": "underground_ores" OR ["underground_ores", "vegetal_decoration"] // one or more decoration steps; optional field, defaults to all steps if not specified
+     * }
+     * </pre>
+     * 
+     * @param biomes Biomes to remove features from.
+     * @param features PlacedFeatures to remove from biomes.
+     * @param steps Decoration steps to remove features from.
+     */
+    public static record RemoveFeaturesBiomeModifier(HolderSet<Biome> biomes, HolderSet<PlacedFeature> features, Set<Decoration> steps) implements BiomeModifier
+    {
+        /**
+         * Creates a modifier that removes the given features from all decoration steps in the given biomes.
+         * @param biomes Biomes to remove features from.
+         * @param features PlacedFeatures to remove from biomes.
+         */
+        public static RemoveFeaturesBiomeModifier allSteps(HolderSet<Biome> biomes, HolderSet<PlacedFeature> features)
+        {
+            return new RemoveFeaturesBiomeModifier(biomes, features, EnumSet.allOf(Decoration.class));
+        }
+        
+        @Override
+        public void modify(Holder<Biome> biome, Phase phase, Builder builder)
+        {
+            if (phase == Phase.REMOVE && this.biomes.contains(biome))
+            {
+                BiomeGenerationSettingsBuilder generationSettings = builder.getGenerationSettings();
+                for (Decoration step : this.steps)
+                {
+                    generationSettings.getFeatures(step).removeIf(this.features::contains);
+                }
+            }
+        }
+
+        @Override
+        public Codec<? extends BiomeModifier> codec()
+        {
+            return ForgeMod.REMOVE_FEATURES_BIOME_MODIFIER_TYPE.get();
+        }
+    }
+    
+    /**
+     * <p>Stock biome modifier that adds a mob spawn to a biome. Has the following json format:</p>
+     * <pre>
+     * {
+     *   "type": "forge:add_spawns", // Required
+     *   "biomes": "#namespace:biome_tag", // Accepts a biome id, [list of biome ids], or #namespace:biome_tag
+     *   "spawners":
+     *   {
+     *     "type": "namespace:entity_type", // Type of mob to spawn
+     *     "weight": 100, // int, spawn weighting
+     *     "minCount": 1, // int, minimum pack size
+     *     "maxCount": 4, // int, maximum pack size
+     *   }
+     * }
+     * </pre>
+     * <p>Optionally accepts a list of spawner objects instead of a single spawner:</p>
+     * <pre>
+     * {
+     *   "type": "forge:add_spawns", // Required
+     *   "biomes": "#namespace:biome_tag", // Accepts a biome id, [list of biome ids], or #namespace:biome_tag
+     *   "spawners":
+     *   [
+     *     {
+     *       "type": "namespace:entity_type", // Type of mob to spawn
+     *       "weight": 100, // int, spawn weighting
+     *       "minCount": 1, // int, minimum pack size
+     *       "maxCount": 4, // int, maximum pack size
+     *     },
+     *     {
+     *       // additional spawner object
+     *     }
+     *   ]
+     * }
+     * </pre>
+     * 
+     * @param biomes Biomes to add mob spawns to.
+     * @param spawners List of SpawnerDatas specifying EntityType, weight, and pack size.
+     */
+    public record AddSpawnsBiomeModifier(HolderSet<Biome> biomes, List<SpawnerData> spawners) implements BiomeModifier
+    {
+        /**
+         * Convenience method for using a single spawn data.
+         * @param biomes Biomes to add mob spawns to.
+         * @param spawner SpawnerData specifying EntityTYpe, weight, and pack size.
+         * @return AddSpawnsBiomeModifier that adds a single spawn entry to the specified biomes.
+         */
+        public static AddSpawnsBiomeModifier singleSpawn(HolderSet<Biome> biomes, SpawnerData spawner)
+        {
+            return new AddSpawnsBiomeModifier(biomes, List.of(spawner));
+        }
+        
+        @Override
+        public void modify(Holder<Biome> biome, Phase phase, Builder builder)
+        {
+            if (phase == Phase.ADD && this.biomes.contains(biome))
+            {
+                MobSpawnSettingsBuilder spawns = builder.getMobSpawnSettings();
+                for (SpawnerData spawner : this.spawners)
+                {
+                    EntityType<?> type = spawner.type;
+                    spawns.addSpawn(type.getCategory(), spawner);
+                }
+            }
+        }
+
+        @Override
+        public Codec<? extends BiomeModifier> codec()
+        {
+            return ForgeMod.ADD_SPAWNS_BIOME_MODIFIER_TYPE.get();
+        }
+    }
+
+    /**
+     * <p>Stock biome modifier that removes mob spawns from a biome. Has the following json format:</p>
+     * <pre>
+     * {
+     *   "type": "forge:add_spawns", // Required
+     *   "biomes": "#namespace:biome_tag", // Accepts a biome id, [list of biome ids], or #namespace:biome_tag
+     *   "entity_types": #namespace:entitytype_tag // Accepts an entity type, [list of entity types], or #namespace:entitytype_tag
+     * }
+     * </pre>
+     * 
+     * @param biomes Biomes to add mob spawns to.
+     * @param entityTypes EntityTypes to remove from spawn lists.
+     */
+    public record RemoveSpawnsBiomeModifier(HolderSet<Biome> biomes, HolderSet<EntityType<?>> entityTypes) implements BiomeModifier
+    {
+        @Override
+        public void modify(Holder<Biome> biome, Phase phase, Builder builder)
+        {
+            if (phase == Phase.REMOVE && this.biomes.contains(biome))
+            {
+                MobSpawnSettingsBuilder spawnBuilder = builder.getMobSpawnSettings();
+                for (MobCategory category : MobCategory.values())
+                {
+                    List<SpawnerData> spawns = spawnBuilder.getSpawner(category);
+                    spawns.removeIf(spawnerData -> this.entityTypes.contains(ForgeRegistries.ENTITIES.getHolder(spawnerData.type).get()));
+                }
+            }
+        }
+
+        @Override
+        public Codec<? extends BiomeModifier> codec()
+        {
+            return ForgeMod.REMOVE_SPAWNS_BIOME_MODIFIER_TYPE.get();
+        }
+    }
+}