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tutorial:features

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Generating Features in your World

Rocks, trees, ores, and ponds are all examples of Features. They are simple generation additions to the world which generate depending on how they are configured. In this tutorial, we'll look at generating a simple stone spiral feature in our world randomly.

Creating a Feature class

A simple Feature looks like this:

  1. public class StoneSpiralFeature extends Feature<DefaultFeatureConfig> {
  2.  
  3. public StoneSpiralFeature(Function<Dynamic<?>, ? extends DefaultFeatureConfig> config) {
  4. super(config);
  5. }
  6.  
  7. @Override
  8. public boolean generate(IWorld world, ChunkGenerator<? extends ChunkGeneratorConfig> chunkGenerator, Random random, BlockPos pos, DefaultFeatureConfig config) {
  9. BlockPos topPos = world.getTopPosition(Heightmap.Type.WORLD_SURFACE, pos);
  10. Direction offset = Direction.NORTH;
  11.  
  12. for (int y = 1; y < 16; y++) {
  13. offset = offset.rotateYClockwise();
  14. world.setBlockState(topPos.up(y).offset(offset), Blocks.STONE.getDefaultState(), 3);
  15. }
  16.  
  17. return true;
  18. }
  19. }

The constructor takes in a Function<Dynamic<? extends DefaultFeatureConfig», which is a factory for data fixer config instances. You can pass in DefaultFeatureConfig::deserialize for default config features, either directly in the super call or when you instantiate the feature.

`generate` is called when the chunk decides to generate the feature. If the feature is configured to spawn every chunk, this would be called for each chunk being generated as well. In the case of the feature being configured to spawn at a certain rate per biome, `generate` would only be called in instances where the world wants to spawn the structure.

In our implementation, we'll build a simple 16-block tall spiral of stone starting at the top block in the world:

@Override
public boolean generate(IWorld world, ChunkGenerator<? extends ChunkGeneratorConfig> chunkGenerator, Random random, BlockPos pos, DefaultFeatureConfig config) {
    BlockPos topPos = world.getTopPosition(Heightmap.Type.WORLD_SURFACE, pos);
    Direction offset = Direction.NORTH;
 
    for (int y = 1; y < 16; y++) {
        offset = offset.rotateYClockwise();
        world.setBlockState(topPos.up(y).offset(offset), Blocks.STONE.getDefaultState(), 3);
    }
 
    return true;
}

Registering a Feature

Features can be registered like most other content in the game, and there aren't any special builders or mechanics you'll have to worry about.

private static final Feature<DefaultFeatureConfig> LAVA_HOLE = Registry.register(
	Registry.FEATURE,
	new Identifier("tutorial", "stone_spiral"),
	new StoneSpiralFeature(DefaultFeatureConfig::deserialize)
);

Adding a Feature to a Biome

Biome has a method called addFeature, which is used to add Features to the biome's generation process. You can view more detailed usage of this method inside each Biome class (such as ForestBiome or SavannaBiome).

We can iterate over Registry.BIOME to add our Feature to every Biome.

Registry.BIOME.forEach(biome -> biome.addFeature(
        GenerationStep.Feature.RAW_GENERATION,
	Biome.configureFeature(
		LAVA_HOLE,
		new DefaultFeatureConfig(),
		Decorator.CHANCE_HEIGHTMAP,
		new ChanceDecoratorConfig(100)
	)
));

The first argument of addFeature helps determine when the structure is generated. For above-ground houses you may go with SURFACE_STRUCTURES, and for caves, you might go with RAW_GENERATION.

The second argument of addFeature is a ConfiguredFeature, which you can create through Biome.configureFeature. The latter takes in an instance of your feature, an instance of your feature's config class, a decorator, and a decorator config.

The Decorator represents how the world chooses to place your Feature. CHANCE_HEIGHTMAP works by looking at a heightmap, whereas NOISE_HEIGHTMAP_32 works with noise. To choose the correct Decorator, check out vanilla Features with a similar style to your own. The decorator config branches off this; in the case of CHANCE_HEIGHTMAP, you would pass in an instance of ChanceHeightmapDecorator.

Results

tutorial/features.1572659903.txt.gz · Last modified: 2019/11/02 01:58 by draylar