Differences

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--- tutorial:chunkgenerator [2022/12/05 16:35] – added clarification to multithreaded chunk generation miir
+++ tutorial:chunkgenerator [2025/02/08 20:28] (current) – adds note to use Registries.CHUNK_GENERATOR on 1.19.3 and above 3xpl0173d
@@ Line 97: / Line 97: @@
 ==== 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>
 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>
 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]].