Groovy World

Groovy World provides a collection of tools for defining custom feature generators (ores, surface decorations, etc.) in GroovyScript.

You can register features with your own world generation logic in a closure:

mods.groovyworld.featureRegistry.addFeature("my_cool_feature") { rng, world, chunkMinX, chunkMinZ ->
    // randomly place one diamond ore block somewhere in the chunk
    world.setBlockState(
            new BlockPos(chunkMinX + rng.nextInt(16), rng.nextInt(64), chunkMinZ + rng.nextInt(16)),
            Blocks.DIAMOND_ORE.getDefaultState())
}

You can also assemble pieces of the Groovy World toolkit to quickly build more complex feature generators:

mods.groovyworld.featureRegistry.addFeature("my_awesome_feature", new FeatureBuilder()
        // only generate the feature in dimension 0 (the overworld)
        .setChunkFilter(ChunkFilters.dimension(0))
        // try to place the feature 4 times per chunk
        .setTriesPerChunk(4) 
        // distribute the feature uniformly between y=4 and y=32
        .setDistribution(FeatureDistributions.uniformY(4, 32))
        // only generate the feature if there is a stone block at the target position
        .setBlockFilter(BlockFilters.naturalStone())
        // paint a sphere of ore at the target position
        .setPainter(Painters.brush(
                BrushGeometries.sphere(2.5), // paint a sphere of radius 2.5
                BlockFilters.naturalStone(), // only paint the ore over stone blocks
                BlockPalettes.block(Blocks.DIAMOND_ORE, Blocks.GOLD_ORE))) // pick either diamond or gold for each ore
        .build())

For more information and examples, check out the GitHub repository.