Root system feature

Warning

Advanced Knowledge Required - This documentation page is intended for users with in-depth knowledge of the world generation system. Beginner users may find the content challenging to understand.

The root_system feature can be used to generate trees with roots.

Configuration

A root system feature has the following configuration options:

Option	Type	Description
`feature`	A `PlacedFeature` (or id in Json)	The feature to place at the tree position.
`required_vertical_space_for_tree`	An `int`. (Range limit in Json is \([1;64]\))	The amount of vertical space required for the tree to grow.
`root_radius`	An `int`. (Range limit in Json is \([1;64]\))	The radius of the root system.
`root_replaceable`	A block tag (prefixed with `#` in Json)	The blocks that can be replaced by roots.
`root_state_provider`	A `BlockStateProvider`	The block state to use for the root.
`root_placement_attempts`	An `int`. (Range limit in Json is \([1;256]\))	The amount of attempts to place a root.
`root_column_max_height`	An `int`. (Range limit in Json is \([1;4096]\))	The maximum height of a root column.
`hanging_root_radius`	An `int`. (Range limit in Json is \([1;64]\))	The radius of hanging roots.
`hanging_roots_vertical_span`	An `int`. (Range limit in Json is \([0;16]\))	The vertical span of hanging roots.
`hanging_root_state_provider`	A `BlockStateProvider`	The block state to use for the hanging root.
`hanging_root_placement_attempts`	An `int`. (Range limit in Json is \([1;256]\))	The amount of attempts to place a hanging root.
`allowed_vertical_water_for_tree`	An `int`. (Range limit in Json is \([0;64]\))	The amount of vertical water allowed for the tree to grow.
`allowed_tree_position`	A `BlockPredicate`	A predicate to check if the tree position is valid.

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

Example

As an example, here's the configured- and placed feature for the azalea tree

KotlinJson

ConfiguredFeatures.kt

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

    val ROOTED_AZALEA_TREE = registerConfiguredFeature(
        "rooted_azalea_tree",
        Feature.ROOT_SYSTEM,
        RootSystemConfiguration(
            PlacementUtils.inlinePlaced(VanillaRegistryAccess.getHolder(TreeFeatures.AZALEA_TREE)), // feature
            3, // required_vertical_space_for_tree
            3, // root_radius
            BlockTags.AZALEA_ROOT_REPLACEABLE, // root_replaceable
            BlockStateProvider.simple(Blocks.ROOTED_DIRT), // root_state_provider
            20, // root_placement_attempts
            100, // root_column_max_height
            3, // hanging_root_radius
            2, // hanging_roots_vertical_span
            BlockStateProvider.simple(Blocks.HANGING_ROOTS), // hanging_root_state_provider
            20, // hanging_root_placement_attempts
            2, // allowed_vertical_water_for_tree
            BlockPredicate.allOf( // allowed_tree_position
                BlockPredicate.anyOf(
                    BlockPredicate.matchesBlocks(Blocks.AIR, Blocks.CAVE_AIR, Blocks.VOID_AIR, Blocks.WATER),
                    BlockPredicate.matchesTag(BlockTags.LEAVES),
                    BlockPredicate.matchesTag(BlockTags.REPLACEABLE_PLANTS)
                ),
                BlockPredicate.matchesTag(Direction.DOWN.normal, BlockTags.AZALEA_GROWS_ON)
            )
        )
    )

}

PlacedFeatures.kt

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

    val ROOTED_AZALEA_TREE = placedFeature("rooted_azalea_tree", ConfiguredFeatures.ROOTED_AZALEA_TREE)
        .count(UniformInt.of(1, 2))
        .inSquareSpread()
        .inYWorldBounds() // (1)!
        .environmentScan(Direction.UP, BlockPredicate.solid(), BlockPredicate.ONLY_IN_AIR_PREDICATE, 12)
        .randomVerticalOffset(-1)
        .biomeFilter()
        .register()

}

Set the y-level to a random int up to 256. The call is equivalent to

HeightRangePlacement.uniform(VerticalAnchor.bottom(), VerticalAnchor.absolute(256));

Search for the first solid block upwards.

configured_feature/rooted_azalea_tree.json

{
  "type": "minecraft:root_system",
  "config": {
    "allowed_tree_position": {
      "type": "minecraft:all_of",
      "predicates": [
        {
          "type": "minecraft:any_of",
          "predicates": [
            {
              "type": "minecraft:matching_blocks",
              "blocks": [
                "minecraft:air",
                "minecraft:cave_air",
                "minecraft:void_air",
                "minecraft:water"
              ]
            },
            {
              "type": "minecraft:matching_block_tag",
              "tag": "minecraft:leaves"
            },
            {
              "type": "minecraft:matching_block_tag",
              "tag": "minecraft:replaceable_plants"
            }
          ]
        },
        {
          "type": "minecraft:matching_block_tag",
          "offset": [
            0,
            -1,
            0
          ],
          "tag": "minecraft:azalea_grows_on"
        }
      ]
    },
    "allowed_vertical_water_for_tree": 2,
    "feature": {
      "feature": "minecraft:azalea_tree",
      "placement": []
    },
    "hanging_root_placement_attempts": 20,
    "hanging_root_radius": 3,
    "hanging_root_state_provider": {
      "type": "minecraft:simple_state_provider",
      "state": {
        "Name": "minecraft:hanging_roots",
        "Properties": {
          "waterlogged": "false"
        }
      }
    },
    "hanging_roots_vertical_span": 2,
    "required_vertical_space_for_tree": 3,
    "root_column_max_height": 100,
    "root_placement_attempts": 20,
    "root_radius": 3,
    "root_replaceable": "#minecraft:azalea_root_replaceable",
    "root_state_provider": {
      "type": "minecraft:simple_state_provider",
      "state": {
        "Name": "minecraft:rooted_dirt"
      }
    }
  }
}

placed_feature/rooted_azalea_tree.json

{
  "feature": "minecraft:rooted_azalea_tree",
  "placement": [
    {
      "type": "minecraft:count",
      "count": {
        "type": "minecraft:uniform",
        "value": {
          "max_inclusive": 2,
          "min_inclusive": 1
        }
      }
    },
    {
      "type": "minecraft:in_square"
    },
    {
      "type": "minecraft:height_range",
      "height": {
        "type": "minecraft:uniform",
        "max_inclusive": {
          "absolute": 256
        },
        "min_inclusive": {
          "above_bottom": 0
        }
      }
    },
    {
      "type": "minecraft:environment_scan",
      "allowed_search_condition": {
        "type": "minecraft:matching_blocks",
        "blocks": "minecraft:air"
      },
      "direction_of_search": "up",
      "max_steps": 12,
      "target_condition": {
        "type": "minecraft:solid"
      }
    },
    {
      "type": "minecraft:random_offset",
      "xz_spread": 0,
      "y_spread": -1
    },
    {
      "type": "minecraft:biome"
    }
  ]
}

Result

Example