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Disk feature

The disk feature allows you to place disks of blocks in the world.

Configuration

The disk feature has the following configuration options:

Option Type Description
state_provider See below. The block state to use for the disk.
target A BlockPredicate. Must be passed in order to generate the disk.
radius An IntProvider (Range limit in Json is \([0;8]\)). Determines the radius of the disk.
half_height An int. (Range limit in Json is \([0;8]\)). Defines half of the height of the disk.

In code, the DiskConfiguration class is used to configure the feature.

State provider

The state provider has 2 main options. fallback, a BlockStateProvider that is used if none of the rules apply, and rules, a list of Rules. Each rule has a BlockPredicate via the if_true option, and a BlockStateProvider via the then option. In code, the class is called RuleBasedBlockStateProvider.

Examples

As an example, here's the configured and placed feature for sand disks in lakes:

ConfiguredFeatures.kt
@OptIn(ExperimentalWorldGen::class)
@Init(stage = InitStage.POST_PACK_PRE_WORLD)
object ConfiguredFeatures : FeatureRegistry by ExampleAddon.registry {

    val DISK_SAND = registerConfiguredFeature(
        "disk_sand",
        Feature.DISK,
        DiskConfiguration(
            RuleBasedBlockStateProvider(
                BlockStateProvider.simple(Blocks.SAND), // (1)!
                listOf(
                    RuleBasedBlockStateProvider.Rule(BlockPredicate.matchesBlocks(Direction.DOWN.normal, Blocks.AIR), BlockStateProvider.simple(Blocks.SANDSTONE)), // (2)!
                )
            ),
            BlockPredicate.matchesBlocks(Blocks.DIRT, Blocks.GRASS_BLOCK), // (3)!
            UniformInt.of(2, 6), // (4)!
            2 // (5)!
        )
    )

}
  1. This is the fallback block used if none of the rules listed below apply. Here, we use sand as the fallback if the block below is not air.
  2. If the block below is air, use sandstone since sand would fall down.
  3. Only allow dirt or grass_block in the center.
  4. Randomly chooses a radius between 2 and 6.
  5. The half_height of the disk.
    The actual height will be \(2 \times 2 + 1 = 5\) blocks.
PlacedFeatures.kt
@OptIn(ExperimentalWorldGen::class)
@Init(stage = InitStage.POST_PACK_PRE_WORLD)
object PlacedFeatures: FeatureRegistry by ExampleAddon.registry {

    val DISK_SAND = placedFeature("disk_sand", ConfiguredFeatures.DISK_SAND)
        .count(3) // (1)!
        .inSquareSpread() // (2)!
        .moveToTopSolid() // (3)!
        .blockPredicateFilter(BlockPredicate.matchesFluids(Fluids.WATER)) // (4)!
        .biomeFilter() // (5)!
        .register()

}
  1. 3 tries per chunk.
  2. Spread the disks in a square.
  3. Makes sure to move the y coordinate to one block above the first solid block. This call is equivalent to 
    HeightmapPlacement.onHeightmap(Heightmap.Types.OCEAN_FLOOR_WG)
  4. Only place the disk if the block is water.
  5. Only place the disk if the current biome has sand disks.
configured_feature/disk_sand.json
{
  "type": "minecraft:disk",
  "config": {
    "half_height": 2,
    "radius": { // (1)!
      "type": "minecraft:uniform",
      "value": {
        "max_inclusive": 6,
        "min_inclusive": 2
      }
    },
    "state_provider": {
      "fallback": { // (2)!
        "type": "minecraft:simple_state_provider",
        "state": {
          "Name": "minecraft:sand"
        }
      },
      "rules": [  // (3)!
        {
          "if_true": {
            "type": "minecraft:matching_blocks",
            "blocks": "minecraft:air",
            "offset": [
              0,
              -1,
              0
            ]
          },
          "then": {
            "type": "minecraft:simple_state_provider",
            "state": {
              "Name": "minecraft:sandstone"
            }
          }
        }
      ]
    },
    "target": { // (4)!
      "type": "minecraft:matching_blocks",
      "blocks": [
        "minecraft:dirt",
        "minecraft:grass_block"
      ]
    }
  }
}
  1. Randomly chooses a radius between 2 and 6.
  2. If the block isn't air, use sand.
  3. Otherwise, if the block below is air, use sandstone.
  4. Only allow dirt or grass_block in the center.
placed_feature/disk_sand.json
{
  "feature": "minecraft:disk_sand",
  "placement": [
    {
      "type": "minecraft:count",
      "count": 3 // (1)!
    },
    {
      "type": "minecraft:in_square" // (2)!
    },
    {
      "type": "minecraft:heightmap", // (3)!
      "heightmap": "OCEAN_FLOOR_WG"
    },
    {
      "type": "minecraft:block_predicate_filter", // (4)!
      "predicate": {
        "type": "minecraft:matching_fluids",
        "fluids": "minecraft:water"
      }
    },
    {
      "type": "minecraft:biome" // (5)!
    }
  ]
}
  1. 3 tries per chunk.
  2. Spread the disks in a square.
  3. Makes sure to move the y coordinate to one block above the first solid block.
  4. Only place the disk if the block is water.
  5. Only place the disk if the current biome has sand disks.

Result

Example