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tutorial:chunkgenerator [2022/09/07 04:20] – created draft version, github repo coming soon miirtutorial:chunkgenerator [2025/02/08 20:28] (current) – adds note to use Registries.CHUNK_GENERATOR on 1.19.3 and above 3xpl0173d
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-===== Custom Chunk Generators (DRAFT) =====+===== Custom Chunk Generators =====
  
 ''ChunkGenerator''s are the mechanisms by which the game generates the world. They handle terrain shaping, surface building, and biome placement.  ''ChunkGenerator''s are the mechanisms by which the game generates the world. They handle terrain shaping, surface building, and biome placement. 
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 <code java> <code java>
 public class ExampleChunkGenerator extends ChunkGenerator { public class ExampleChunkGenerator extends ChunkGenerator {
-    /* this is a very important field, we will come back to the codec later+    /* this is a very important field, we will come back to the codec later */
     public static final Codec<ExampleChunkGenerator> CODEC;      public static final Codec<ExampleChunkGenerator> CODEC; 
  
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     /* this method builds the shape of the terrain. it places stone everywhere, which will later be overwritten with grass, terracotta, snow, sand, etc     /* this method builds the shape of the terrain. it places stone everywhere, which will later be overwritten with grass, terracotta, snow, sand, etc
-     by the buildSurface method. it also is responsible for putting the water in oceans. */+     by the buildSurface method. it also is responsible for putting the water in oceans. it returns a CompletableFuture-- you'll likely want this to be delegated to worker threads. */
     @Override     @Override
     public CompletableFuture<Chunk> populateNoise(Executor executor, Blender blender, NoiseConfig noiseConfig, StructureAccessor structureAccessor, Chunk chunk) {     public CompletableFuture<Chunk> populateNoise(Executor executor, Blender blender, NoiseConfig noiseConfig, StructureAccessor structureAccessor, Chunk chunk) {
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 ==== Registering and Codecs ==== ==== Registering and Codecs ====
  
-Like other features in the game, ''ChunkGenerators'' have to be registered. However, you don't pass the registry a static instance-- instead, you give it a ''Codec'' instance. You can put whatever you want in the codec-- Mojang provides serialization codecs for a lot of useful objects, including entire registries. Then, all that's left is to register your chunk generator. Put the following line into your mod initializer ''onInitialize'' method:+Like other features in the game, ''ChunkGenerator''s have to be registered. However, you don't pass the registry a static instance-- instead, you give it a ''Codec'' instance. You can put whatever you want in the codec-- Mojang provides serialization codecs for a lot of useful objects, including entire registries. The easiest way to do this is via ''RecordCodecBuilder''. Here's an example codec: 
 +<code java> 
 +    public static final Codec<ExampleChunkGenerator> CODEC = RecordCodecBuilder.create(instance -> 
 +        instance.group( 
 +                BiomeSource.CODEC.fieldOf("biome_source").forGetter(ExampleChunkGenerator::getBiomeSource), 
 +                Codec.INT.fieldOf("sea_level").forGetter(ExampleChunkGenerator::getSeaLevel), 
 +                Codec.INT.fieldOf("world_height").forGetter(ExampleChunkGenerator::getWorldHeight), 
 +                Identifier.fieldOf("custom_block").forGetter(ExampleChunkGenerator::getCustomBlockID) 
 +                ).apply(instance, ExampleChunkGenerator::new)); 
 +</code> 
 +Each line in the codec corresponds to a different field in your chunk generator that should be configurable. In this example, I pass a ''BiomeSource'' and a few ''int''s. Most objects you will want to add into your chunk generator will have a ''Codec'' defined for them. Primitives have theirs defined in the ''Codec'' class, and other classes (for example, ''BiomeSource'' or ''Identifier'') have theirs defined in their classes. 
 + 
 +To use the fields properly, you have to add them, along with getters, into your class: 
 + 
 +<code java> 
 +private final BiomeSource biomeSource; 
 +public BiomeSource getBiomeSource() { 
 +    return this.biomeSource; 
 +} 
 +private final int seaLevel; 
 +public int getSeaLevel() { 
 +    return this.seaLevel; 
 +} 
 +// and the same for the other fields 
 +</code> 
 + 
 +and then, create a constructor for your generator that uses each of those fields **in the same order that you listed them in the codec**: 
 +<code java> 
 +public ExampleChunkGenerator(BiomeSource biomeSource, int seaLevel, int worldHeight, Identifier customBlockID) { 
 +    super(biomeSource); 
 +    this.seaLevel = seaLevel; 
 +    this.worldHeight = worldHeight; 
 +    this.customBlock = Registries.BLOCK.getOrThrow(RegistryKey.of(RegistryKeys.BLOCK, defaultBlock)).getDefaultState(); 
 +    this.customBlockID = customBlockID; // this line is included because we need to have a getter for the ID specifically 
 +} 
 +</code> 
 + 
 + 
 +Then, all that's left is to register your chunk generator. Put the following line into your mod initializer ''onInitialize'' method:
 <code java> <code java>
 Registry.register(Registry.CHUNK_GENERATOR, new Identifier("wiki-example", "example"), ExampleChunkGenerator.CODEC); Registry.register(Registry.CHUNK_GENERATOR, new Identifier("wiki-example", "example"), ExampleChunkGenerator.CODEC);
 +</code>
 +//* For Minecraft Versions 1.19.3 and above, use ''Registries.CHUNK_GENERATOR'' instead of ''Registry.CHUNK_GENERATOR''
 +//
 +
 +Now, you can create json files to use your new chunk generator:
 +<code json>
 +// resources/data/wiki-example/dimension/example.json
 +{
 +  "type": "minecraft:overworld",
 +  "generator": {
 +    "type": "wiki-example:example",
 +    "custom_block": "minecraft:dirt",
 +    "sea_level": 0,
 +    "world_height": 384,
 +    "biome_source": // etc.
 </code> </code>
  
 And you're done! If you want to use your new generator, it might be helpful to wrap it with a [[tutorial:world_presets|WorldPreset]]. And you're done! If you want to use your new generator, it might be helpful to wrap it with a [[tutorial:world_presets|WorldPreset]].
tutorial/chunkgenerator.1662524423.txt.gz · Last modified: 2022/09/07 04:20 by miir