API reference / @jsprismarine/features

@jsprismarine/features

Java Edition's decoration pass in TypeScript: all 58 feature types, the ten block state providers and the value providers they are built from, all 18 placement modifiers, and the seeded pipeline that runs them. Everything is read from Mojang's published worldgen/* JSON at load time and pinned to Java Edition 26.3.

import { decorateChunk, FeatureLoader, TestFeatureWorld } from '@jsprismarine/features';

const loader = new FeatureLoader({
    feature: (id) => featureDocuments.get(id),
    placedFeature: (id) => placedDocuments.get(id),
    blockStateProvider: (id) => providerDocuments.get(id)
});

const world = new TestFeatureWorld();
decorateChunk(
    [{ feature: loader.placedFeatureById('minecraft:ore_diamond'), step: 'underground_ores', index: 0 }],
    { world },
    1234n,
    3,
    -5
);

Block states come out as Java identifiers, because that is what the data names. translatingWorld is where a server attaches @jsprismarine/mapping, so nothing here knows that two editions exist.

Coverage

Measured against the pinned 26.3 data rather than quoted, by the gated corpus test in src/corpus.test.ts.

Registry	Registered	Implemented	Used by vanilla
worldgen/feature_type	58	58	47 at the top level, 56 reachable through nesting
worldgen/placement_modifier_type	18	18	15
worldgen/block_state_provider_type	10	10	9, counting simple in its shorthand form
int_provider_type	8	8	8, counting constant as a bare number
float_provider_type	4	4	4, same
height_provider_type	6	6	6, counting constant as a bare anchor
block_predicate_type	16	16	14
rule_test	10	10	7
worldgen/trunk_placer_type	10	10	10
worldgen/foliage_placer_type	12	12	12
worldgen/tree_decorator_type	11	11	10
worldgen/root_placer_type	1	1	1
worldgen/feature_size_type	2	2	2

All 240 configured features and all 273 placed features parse with zero errors. The top of the usage table is tree 45, simple_block 37, ore 30, random_selector 21, overlay 10, weighted_random_selector 8, and block_column, fallen_tree, spring_feature and vegetation_patch at 6 each.

Two things changed in 26.3 that a loader written against 1.21 data gets wrong. random_patch is gone, replaced by projected_random_patchy_square, which thins toward the corners of its square instead of scattering uniformly. And pointed_dripstone and dripstone_cluster became speleothem and speleothem_cluster with their two blocks configurable, which is what lets the nether's sulfur spikes reuse them.

The pipeline and its seeding

A placed feature is a configured feature plus a list of modifiers. placeFeature runs the list and builds the feature at every position it yields.

The traversal is depth first, not stage by stage. The first position a modifier emits runs all the way to the end of the chain before the second one starts. That decides the order of the random draws, so a breadth-first version with the same modifiers produces a different world from the same seed. src/placement/pipeline.ts reproduces Java's stack.

decorateChunk runs a whole chunk. It derives the population seed once from the world seed and the chunk's corner, then reseeds the stream before each feature from that seed, the feature's index in the flattened per-step list, and the step's ordinal. Three properties follow, and the suite checks all three: the same seed and chunk produce the same blocks, a feature that draws fifty extra numbers does not move the next one, and running a subset of the plan leaves the rest where it was.

The eleven decoration steps run in Java's order: raw generation, lakes, local modifications, underground structures, surface structures, strongholds, underground ores, underground decoration, fluid springs, vegetal decoration, top layer modification. orderDecoration sorts a plan into that order, by step and then by index within the step.

WorldgenRandom is not one of @jsprismarine/worldgen's two sources. Java's class extends LegacyRandomSource and overrides only next(bits), so every derived draw uses java.util.Random's formulas over a Xoroshiro bit stream. Handing a feature a plain XoroshiroRandomSource produces different numbers from the first float onward.

The FeatureWorld seam

Features never see a chunk, a section, a palette or a Bedrock identifier. They read and write Java block states through one interface.

interface FeatureWorld {
    readonly minY: number;
    readonly height: number;
    readonly seaLevel: number;
    readonly seed: bigint;
    readonly blocks: BlockOracle;
    getBlock(position: BlockPos): BlockState;
    setBlock(position: BlockPos, state: BlockState): boolean;
    getHeight(heightmap: HeightmapType, x: number, z: number): number;
    getBiome(position: BlockPos): string;
}

BlockOracle is a second, smaller interface for the facts about a block state that do not depend on where it sits: isAir, isSolid, isSturdy, isReplaceable, fluid, hasTag and canSurvive. It is separate because the answers are pure and shared. A server builds one oracle from its block registry and tag tables and reuses it for every chunk, while a world adapter exists for one decorated region. A feature still takes one object, because the oracle hangs off the world.

Five optional members cover what a feature needs and world generation does not own: isColdEnoughToSnow for freeze_top_layer and the lake's ice, setBlockEntity for the two chests and the spawner, placeTemplate for template and fossil, spawnEntity for the end spike's crystal, and tagMembers for the one state provider that enumerates a tag rather than testing it. When one is absent the feature does the visible part and skips the rest rather than failing. spawnEntity takes an EntitySpawnOptions object carrying the yaw and the crystal's beam target, base plate and invulnerability, which the server applies to the entity it spawns.

TestFeatureWorld is the in-memory adapter the tests use. It records every write in order, computes heightmaps from the stored blocks so a feature that reads a heightmap after writing sees its own work, and takes its block facts from createTestOracle, which builds an oracle from plain tables of air, fluid, replaceable and tagged identifiers.

translatingWorld(target, mapper, blocks) wraps a world that stores some other state type. That is where @jsprismarine/mapping's Java-to-Bedrock function goes, applied once at the seam rather than inside every feature.

Parity

Two layers, verified two different ways.

The layer below the features is checked against Java itself. utils/oracle/DumpFeatureVectors.java compiles against the pinned 26.3 server jar and writes vectors/features.json, and the tests compare exactly, not within a tolerance.

Stage	Vectors	Result
setDecorationSeed	6 world seeds times 6 chunks	exact
setFeatureSeed and the first three draws	36 chunks times 11 steps times 3 indices	exact
All 11 int providers	24 draws each	exact
All 4 float providers	24 draws each	exact
All 7 height provider shapes	24 draws each	exact
WeightedList.getRandomOrThrow	64 draws	exact
Biome.BIOME_INFO_NOISE	5 positions	exact
Mth.randomBetweenInclusive, nextInt, randomBetween, normal	16 rounds each	exact

Refresh the vectors with pnpm --filter @jsprismarine/features run vectors, which needs the pinned jar (pnpm --filter @jsprismarine/bedrock-data run dump:java) and a JDK 25 or newer.

The features and the placement modifiers themselves are checked by behavior and distribution instead. A Java feature takes a WorldGenLevel, which cannot be stood up outside a running server, so there is no cheap way to ask Java what blocks minecraft:oak puts where. The tests assert shape, extent, draw counts and rates: an ore vein stays inside its bounding box across twenty seeds, a geode's four shells nest, a lake's fluid sits below its air, an oak's trunk is a contiguous run of four to six logs with leaves only above it, and the patchy square thins toward its corners.

Against Bedrock the positions cannot match at all, and this is not a gap that effort closes. Bedrock's generator uses an undocumented random source, so the same world seed picks different positions even where the rules agree. cross-edition-worldgen-parity.md section 4 measures where the rules do agree: coal ore's counts, heights, sizes, discard chances and distributions are identical in the two editions, the amethyst geode agrees on chance, height range, block layers and layer probabilities, and the plains flower patch agrees on its 64 tries and its plus or minus 6 by 2 spread while disagreeing on the rate. Test distributions, not equality.

Precision

Java computes much of this in float, and the places where it does are reproduced with Math.fround rather than left as doubles. Two cases are worth naming because they are easy to miss.

Mth.sin and Mth.cos read a 65536-entry float table rather than calling Math.sin. The two differ by up to about 5e-5, which is enough to move an ore vein's sphere radii across a block boundary. support.ts has the table; the worldgen code that calls Mth.sin uses it, and the code that calls java.lang.Math.sin uses Math.sin.

A tree collects its logs, leaves and roots into HashSets, and the decorators then walk them. Java's iteration order is the hash table's bucket order, so which log gets the beehive and which leaf grows a vine depend on BlockPos.hashCode and on how far the table has grown. JavaHashSet reproduces that order.

What a server still has to supply

Seven behaviors live outside world generation in Java too, and they stay outside here. Each one places its visible part and leaves the rest to the caller, so none of them fails silently.

• The sculk spreader. sculk_patch places the seed block. Java runs SculkSpreader, the same charge-and-cursor simulation the sculk catalyst uses at runtime.
• The chorus plant. chorus_plant places the flower. ChorusFlowerBlock.generatePlant grows it.
• The multiface spreader. multiface_growth attaches the first face and draws the roll that decides whether the block's own spreader continues.
• Double plants and mossy carpet. simple_block has two branches in Java for blocks that place more than one block, which need the block registry.
• The pale moss patch. The pale_moss tree decorator runs minecraft:pale_moss_patch from the feature registry, which the decorator context does not hold.
• Structure templates. template and fossil name a template and a processor list and hand them to FeatureWorld.placeTemplate, which is where @jsprismarine/structures attaches.
• Loot, spawners, gateways and the end crystal. monster_room, bonus_chest, end_gateway and end_spike place their blocks and report what belongs in them through setBlockEntity and spawnEntity.
• The ten spike pillars. Vanilla's end_spike ships an empty spikes list, which means "derive the pillars from the world seed". endSpikesForSeed ports Java's derivation: the seed reduces to a 16-bit key through the legacy LCG's nextLong, a second generator seeded by that key shuffles the indices 0 through 9, and each pillar's radius, height and iron-bar cage follow from its shuffled index.

Known gaps

• fossil scans the origin's own column for the lowest surface, where Java scans the template's whole footprint. The two agree for the four vanilla fossils, which arrive from a heightmap already, and will differ for a datapack fossil wider than one block on sloped ground.
• The matching_biomes block predicate matches biomes by name. A #tag reference matches nothing, because this package holds no biome registry. No vanilla feature uses the predicate.
• random_block needs BlockOracle.tagMembers to enumerate a tag. Without it the provider yields nothing and the caller keeps the existing block, which is Java's behavior for an empty holder set.
• Block states are compared by identifier and property values, not by a palette index, so a blockstate_match rule test compares text. That is the same answer for every vanilla rule and cheaper than carrying a palette.

Running the corpus test

It reads the vanilla datapack from disk, so it is gated:

pnpm --filter @jsprismarine/bedrock-data run fetch:sources
JSP_FEATURE_CORPUS=1 pnpm --filter @jsprismarine/features exec vitest run corpus

JSP_VANILLA_DATAPACK points at a local copy instead. Everything it reads is extracted game data and therefore untrusted: it is parsed with JSON.parse and never executed.

Classes

• FeatureLoader
• JavaHashSet
• TestFeatureWorld
• WorldgenRandom

Interfaces

BlockColumnLayer

Defined in: features/simple.ts:714

One band of a block_column: how many blocks and which state they take.

Properties

height

readonly height: IntProvider

Defined in: features/simple.ts:716

How tall the band is.

provider

readonly provider: BlockStateProvider

Defined in: features/simple.ts:718

What the band is made of.

---

BlockEntityRequest

Defined in: world/FeatureWorld.ts:168

What a feature asks a world to record on a block it just placed.

Properties

exactTeleport?

readonly optional exactTeleport?: boolean

Defined in: world/FeatureWorld.ts:178

Whether an end gateway places its own exit platform.

exitPortal?

readonly optional exitPortal?: BlockPos

Defined in: world/FeatureWorld.ts:176

Where an end gateway sends a traveller, when the block is one.

id

readonly id: string

Defined in: world/FeatureWorld.ts:170

The block entity type, for example minecraft:chest.

javaBlock?

readonly optional javaBlock?: string

Defined in: world/FeatureWorld.ts:187

The Java block the block entity sits in, which is where Java keeps a banner's color.

lootTable?

readonly optional lootTable?: string

Defined in: world/FeatureWorld.ts:172

The loot table to roll when the block is first opened, when there is one.

saved?

readonly optional saved?: unknown

Defined in: world/FeatureWorld.ts:185

The whole block entity as a structure template saved it, when a template saved one.

Typed as unknown because this package does not model NBT and depends on no library that does. The server narrows it before reading it.

spawnEntity?

readonly optional spawnEntity?: string

Defined in: world/FeatureWorld.ts:174

The entity a spawner produces, when the block is a spawner.

---

BlockOracle

Defined in: world/FeatureWorld.ts:48

The facts about a block state that do not depend on where it sits.

This is a separate seam from FeatureWorld because the answers are pure and shared: a server builds one oracle from its block registry and tag tables and reuses it for every chunk, while a world adapter is created per decorated region. A feature reaches it through FeatureWorld.blocks, so a feature still takes one object.

Methods

canSurvive()

canSurvive(world, position, state): boolean

Defined in: world/FeatureWorld.ts:66

Answers Java's BlockState.canSurvive(level, pos) for the would_survive predicate.

Parameters

world

FeatureWorld

position

BlockPos

state

BlockState

Returns

boolean

fluid()

fluid(state): FluidKind

Defined in: world/FeatureWorld.ts:58

Returns the fluid the state holds, counting both source blocks and waterlogging.

Parameters

state

BlockState

Returns

FluidKind

hasTag()

hasTag(state, tag): boolean

Defined in: world/FeatureWorld.ts:64

Answers whether the state is in a block tag.

Parameters

state

BlockState

tag

string

The tag identifier with no leading #, for example minecraft:logs.

Returns

boolean

isAir()

isAir(state): boolean

Defined in: world/FeatureWorld.ts:50

Answers Java's BlockState.isAir().

Parameters

state

BlockState

Returns

boolean

isReplaceable()

isReplaceable(state): boolean

Defined in: world/FeatureWorld.ts:56

Answers Java's BlockState.canBeReplaced(), which decides whether a feature may overwrite it.

Parameters

state

BlockState

Returns

boolean

isSolid()

isSolid(state): boolean

Defined in: world/FeatureWorld.ts:52

Answers Java's BlockState.isSolid(): the block occupies its whole cell and blocks motion.

Parameters

state

BlockState

Returns

boolean

isSturdy()

isSturdy(state, direction): boolean

Defined in: world/FeatureWorld.ts:54

Answers Java's BlockState.isFaceSturdy(level, pos, direction) for a full face.

Parameters

state

BlockState

direction

Direction

Returns

boolean

isUnobstructed()?

optional isUnobstructed(world, position): boolean

Defined in: world/FeatureWorld.ts:72

Answers Java's isUnobstructed: whether a block-shaped box at the position collides with no entity. Optional, because decoration has no entity list and no vanilla feature asks. When absent the unobstructed predicate passes.

Parameters

world

FeatureWorld

position

BlockPos

Returns

boolean

tagMembers()?

optional tagMembers(tag): readonly string[]

Defined in: world/FeatureWorld.ts:78

Lists the blocks in a tag. Optional, because only the random_block state provider needs to enumerate rather than test, and a server that cannot answer gets Java's empty-set behavior: the provider places nothing.

Parameters

tag

string

Returns

readonly string[]

---

BlockPos

Defined in: world/FeatureWorld.ts:4

A block position in world coordinates.

Properties

x

readonly x: number

Defined in: world/FeatureWorld.ts:5

y

readonly y: number

Defined in: world/FeatureWorld.ts:6

z

readonly z: number

Defined in: world/FeatureWorld.ts:7

---

BlockReplacement

Defined in: features/ruleTest.ts:99

A rule test paired with the state to write when it holds, Java's BlockReplacement.

Properties

state

readonly state: BlockState

Defined in: features/ruleTest.ts:103

What to write in its place.

target

readonly target: RuleTest

Defined in: features/ruleTest.ts:101

What the block already there has to be.

---

BlockState

Defined in: world/BlockState.ts:9

A Java Edition block state: an identifier and the property values that distinguish it from the other states of the same block.

Everything this package produces is Java-shaped. Turning a state into the Bedrock palette entry the server stores is @jsprismarine/mapping's job, reached through the import('./FeatureWorld').FeatureWorld adapter rather than from inside a feature.

Properties

name

readonly name: string

Defined in: world/BlockState.ts:11

The namespaced block identifier, for example minecraft:oak_log.

properties

readonly properties: Readonly<Record<string, string>>

Defined in: world/BlockState.ts:13

Property values keyed by name, as strings, exactly as the JSON spells them.

---

BlockStateProvider

Defined in: providers/blockStateProvider.ts:26

Chooses the block a feature places at a position, Java's BlockStateProvider.

Features are built almost entirely out of these: a tree's trunk, its leaves, an ore's two targets, a patch's plant and a vegetation patch's ground are all providers rather than fixed states, which is why one tree implementation covers 45 configured trees.

Properties

type

readonly type: BlockStateProviderTypeName

Defined in: providers/blockStateProvider.ts:28

The provider's registry name.

Methods

getOptionalState()

getOptionalState(world, random, position): BlockState | undefined

Defined in: providers/blockStateProvider.ts:32

Chooses a state, returning undefined rather than falling back.

Parameters

world

FeatureWorld

random

RandomSource

position

BlockPos

Returns

BlockState | undefined

getState()

getState(world, random, position): BlockState

Defined in: providers/blockStateProvider.ts:30

Chooses a state, falling back to the block already at the position when it cannot.

Parameters

world

FeatureWorld

random

RandomSource

position

BlockPos

Returns

BlockState

---

ConfiguredFeature

Defined in: features/Feature.ts:77

A feature type bound to its configuration, Java's ConfiguredFeature.

The 240 vanilla configured features are instances of 47 of the 58 types. Placing one is a pure function of the world, the random stream and an origin, which is what lets the placement pipeline call the same feature at many positions without any per-call setup.

Properties

children?

readonly optional children?: readonly ConfiguredFeature[]

Defined in: features/Feature.ts:88

The features this one may delegate to, so a corpus walk can reach every nested type.

type

readonly type: "sequence" | "bamboo" | "block_blob" | "block_column" | "block_pile" | "blue_ice" | "bonus_chest" | "chorus_plant" | "coral_claw" | "coral_tree" | "delta_feature" | "disk" | "end_gateway" | "end_island" | "end_platform" | "end_podium" | "end_spike" | "fallen_tree" | "fill_layer" | "fossil" | "freeze_top_layer" | "geode" | "huge_brown_mushroom" | "huge_fungus" | "huge_red_mushroom" | "iceberg" | "lake" | "large_dripstone" | "monster_room" | "multiface_growth" | "netherrack_replace_blobs" | "no_op" | "ore" | "overlay" | "projected_random_patchy_square" | "random_boolean_selector" | "random_neighbor_spread" | "random_selector" | "replace_single_block" | "root_system" | "scattered_ore" | "sculk_patch" | "simple_block" | "simple_random_selector" | "single_block_pillar" | "speleothem" | "speleothem_cluster" | "spike" | "spring_feature" | "stepped_column_cluster" | "template" | "tree" | "underwater_magma" | "vegetation_patch" | "vines" | "void_start_platform" | "waterlogged_vegetation_patch" | "weighted_random_selector"

Defined in: features/Feature.ts:79

The feature type's registry name.

Methods

place()

place(world, random, origin): boolean

Defined in: features/Feature.ts:86

Builds the feature at an origin.

Parameters

world

FeatureWorld

random

RandomSource

origin

BlockPos

Returns

boolean

Whether anything was placed. Java uses this to decide whether a placed feature counts as having run, and several wrapper features propagate it.

---

DecorationResult

Defined in: placement/pipeline.ts:138

What decorateChunk did, for a caller that wants to report or assert on it.

Properties

placed

readonly placed: number

Defined in: placement/pipeline.ts:142

How many scheduled features reported placing at least one block.

populationSeed

readonly populationSeed: bigint

Defined in: placement/pipeline.ts:140

The chunk's population seed, Java's "Decoration Seed" crash-report field.

run

readonly run: number

Defined in: placement/pipeline.ts:144

How many were run in total.

---

DecoratorContext

Defined in: features/tree/shared.ts:125

What a decorator sees of the finished tree.

Properties

leaves

readonly leaves: readonly BlockPos[]

Defined in: features/tree/shared.ts:133

Every leaf, sorted the same way.

logs

readonly logs: readonly BlockPos[]

Defined in: features/tree/shared.ts:131

Every log, sorted by y with ties in Java's hash order.

random

readonly random: RandomSource

Defined in: features/tree/shared.ts:129

The stream every draw comes from.

roots

readonly roots: readonly BlockPos[]

Defined in: features/tree/shared.ts:135

Every root, in Java's hash order.

world

readonly world: FeatureWorld

Defined in: features/tree/shared.ts:127

The world being built into.

Methods

setBlock()

setBlock(position, state): void

Defined in: features/tree/shared.ts:137

Writes a decoration block.

Parameters

position

BlockPos

state

BlockState

Returns

void

---

EndSpike

Defined in: features/endSpikes.ts:6

One of the End's ten obsidian pillars, Java's EndSpikeFeature.EndSpike.

Properties

centerX

readonly centerX: number

Defined in: features/endSpikes.ts:8

The pillar's center x in world coordinates.

centerZ

readonly centerZ: number

Defined in: features/endSpikes.ts:10

The pillar's center z in world coordinates.

guarded

readonly guarded: boolean

Defined in: features/endSpikes.ts:16

Whether an iron-bar cage surrounds the pillar's crystal.

height

readonly height: number

Defined in: features/endSpikes.ts:14

The y just above the topmost obsidian, where the bedrock cap and the crystal sit.

radius

readonly radius: number

Defined in: features/endSpikes.ts:12

The obsidian disc's radius.

---

EntitySpawnOptions

Defined in: world/FeatureWorld.ts:156

What a feature declares about an entity it spawns beyond its type and position.

The three crystal fields carry Java's EndSpikeFeature configuration and the end crystal's synced data to the server, which projects them onto the spawned entity.

Properties

beamTarget?

readonly optional beamTarget?: BlockPos

Defined in: world/FeatureWorld.ts:160

The block an end crystal's beam points at, Java's crystal_beam_target.

invulnerable?

readonly optional invulnerable?: boolean

Defined in: world/FeatureWorld.ts:164

Whether the entity ignores damage, Java's crystal_invulnerable.

showBottom?

readonly optional showBottom?: boolean

Defined in: world/FeatureWorld.ts:162

Whether an end crystal renders its bedrock base plate. Java's default is true.

yaw?

readonly optional yaw?: number

Defined in: world/FeatureWorld.ts:158

The spawn yaw in degrees. Defaults to 0.

---

FeatureParsers

Defined in: features/parseContext.ts:12

The nested parsers a feature needs that it cannot import directly.

Features reference placed features, placed features reference features, and both reference the registry. Passing the parsers in rather than importing them keeps the cycle out of the module graph and lets a caller resolve minecraft:oak by identifier instead of inlining it.

Methods

blockStateProvider()

blockStateProvider(source, path): BlockStateProvider

Defined in: features/parseContext.ts:18

Reads a block state provider, resolving a block_state_provider reference.

Parameters

source

unknown

path

string

Returns

BlockStateProvider

direction()

direction(source, path): Direction

Defined in: features/parseContext.ts:22

Reads any of the six directions.

Parameters

source

unknown

path

string

Returns

Direction

fluidState()

fluidState(source, path): BlockState

Defined in: features/parseContext.ts:31

Reads a fluid state as the block state Java's createLegacyBlock would produce.

A fluid state is not a block state in Java, but every use in the feature data names a source fluid, and a source fluid's legacy block is the fluid block at level zero.

Parameters

source

unknown

path

string

Returns

BlockState

identifier()

identifier(source, path): string

Defined in: features/parseContext.ts:20

Reads a registry identifier, normalizing the namespace.

Parameters

source

unknown

path

string

Returns

string

placedFeature()

placedFeature(source, path): PlacedFeature

Defined in: features/parseContext.ts:14

Reads a nested placed feature, which may be an identifier or an inline document.

Parameters

source

unknown

path

string

Returns

PlacedFeature

placedFeatureList()

placedFeatureList(source, path): PlacedFeature[]

Defined in: features/parseContext.ts:16

Reads a list of nested placed features, or a single tag-free identifier.

Parameters

source

unknown

path

string

Returns

PlacedFeature[]

verticalDirection()

verticalDirection(source, path): VerticalDirection

Defined in: features/parseContext.ts:24

Reads up or down.

Parameters

source

unknown

path

string

Returns

VerticalDirection

---

FeatureRegistry

Defined in: features/parse.ts:25

Resolves worldgen/feature and worldgen/placed_feature identifiers.

Both registries reference each other, so a loader hands this one object in and gets a lazily resolving reader back. Vanilla's 240 features and 273 placed features form a graph eleven levels deep in places, which is why resolution is by identifier rather than by inlining.

Methods

blockStateProvider()?

optional blockStateProvider(id): unknown

Defined in: features/parse.ts:36

Returns the parsed JSON of a worldgen/block_state_provider document, or undefined.

26.3 made block state providers a referenceable registry, and vanilla ships eight of them; soil_beneath_tree alone is named by 40 of the 45 configured trees.

Parameters

id

string

Returns

unknown

feature()

feature(id): unknown

Defined in: features/parse.ts:27

Returns the parsed JSON of a worldgen/feature document, or undefined when absent.

Parameters

id

string

Returns

unknown

placedFeature()

placedFeature(id): unknown

Defined in: features/parse.ts:29

Returns the parsed JSON of a worldgen/placed_feature document, or undefined.

Parameters

id

string

Returns

unknown

---

FeatureSize

Defined in: features/tree/shared.ts:67

How wide the tree must be free at each height, Java's FeatureSize.

Properties

minClippedHeight?

readonly optional minClippedHeight?: number

Defined in: features/tree/shared.ts:71

The shortest clipped trunk the tree will still accept, when it accepts one.

type

readonly type: "two_layers_feature_size" | "three_layers_feature_size"

Defined in: features/tree/shared.ts:69

The registry name.

Methods

sizeAtHeight()

sizeAtHeight(treeHeight, y): number

Defined in: features/tree/shared.ts:73

The half-width that must be free at a height above the trunk's base.

Parameters

treeHeight

number

y

number

Returns

number

---

FeatureWorld

Defined in: world/FeatureWorld.ts:93

Everything a feature may do to the world it decorates.

This is the package's only outward seam. Features never see a chunk, a section, a palette or a Bedrock identifier: they read and write Java block states through these seven members, so the server's storage, its Java-to-Bedrock mapping and its chunk lifetime stay on the other side. import('./TestFeatureWorld').TestFeatureWorld is the in-memory adapter the tests use.

Writes are expected to succeed or be dropped silently, as Java's WorldGenLevel.setBlock does outside the region being generated; a feature treats setBlock as advisory and reads back when it needs to know.

Properties

blocks

readonly blocks: BlockOracle

Defined in: world/FeatureWorld.ts:108

The static block facts, shared across worlds.

height

readonly height: number

Defined in: world/FeatureWorld.ts:97

The number of y levels the dimension generates, Java's getHeight().

minY

readonly minY: number

Defined in: world/FeatureWorld.ts:95

The lowest y the dimension generates, Java's getMinY().

seaLevel

readonly seaLevel: number

Defined in: world/FeatureWorld.ts:99

The dimension's sea level, which relative_to_sea_level anchors resolve against.

seed

readonly seed: bigint

Defined in: world/FeatureWorld.ts:106

The world seed.

Only the geode reads it, to build a noise field that is the same everywhere in one world and different between worlds.

Methods

getBiome()

getBiome(position): string

Defined in: world/FeatureWorld.ts:116

Returns the biome identifier at a position.

Parameters

position

BlockPos

Returns

string

getBlock()

getBlock(position): BlockState

Defined in: world/FeatureWorld.ts:110

Returns the state at a position, or air outside the generated region.

Parameters

position

BlockPos

Returns

BlockState

getHeight()

getHeight(heightmap, x, z): number

Defined in: world/FeatureWorld.ts:114

Returns the first y above the topmost block matching the heightmap's predicate.

Parameters

heightmap

HeightmapType

x

number

z

number

Returns

number

isColdEnoughToSnow()?

optional isColdEnoughToSnow(position): boolean

Defined in: world/FeatureWorld.ts:125

Answers Java's Biome.getTemperature(pos) < 0.15, which is the whole of what decides whether freeze_top_layer acts.

Optional, because biome climate lives in the biome source rather than here. When absent nothing freezes, which is the right answer for a warm world and a visible one for a cold world rather than a silent miss.

Parameters

position

BlockPos

Returns

boolean

placeTemplate()?

optional placeTemplate(request): boolean

Defined in: world/FeatureWorld.ts:141

Places a structure template, which template and fossil delegate to.

Optional, and the seam to @jsprismarine/structures: this package names a template and a processor list and does not read NBT. A world that cannot place one reports failure, which propagates through the pipeline the same way an obstructed placement does.

Parameters

request

TemplateRequest

Returns

boolean

setBlock()

setBlock(position, state): boolean

Defined in: world/FeatureWorld.ts:112

Writes a state. Returns whether the write landed.

Parameters

position

BlockPos

state

BlockState

Returns

boolean

setBlockEntity()?

optional setBlockEntity(position, data): void

Defined in: world/FeatureWorld.ts:133

Attaches block entity data to a block this package just wrote.

Optional, because only six features need it: the two chests, the spawner, the two end gateway kinds and the end podium. A world that cannot store it loses the contents rather than the block.

Parameters

position

BlockPos

data

BlockEntityRequest

Returns

void

spawnEntity()?

optional spawnEntity(identifier, position, options?): void

Defined in: world/FeatureWorld.ts:147

Spawns an entity a feature builds around, which is only the end spike's crystal.

Optional, because entities belong to the server rather than to world generation.

Parameters

identifier

string

position

BlockPos

options?

EntitySpawnOptions

Returns

void

---

FloatProvider

Defined in: providers/valueProviders.ts:207

A draw of one float, Java's FloatProvider.

Four types are registered and vanilla uses all four.

Properties

maxValue

readonly maxValue: number

Defined in: providers/valueProviders.ts:213

The highest value the provider can return.

minValue

readonly minValue: number

Defined in: providers/valueProviders.ts:211

The lowest value the provider can return.

type

readonly type: FloatProviderType

Defined in: providers/valueProviders.ts:209

The provider's registry name.

Methods

sample()

sample(random): number

Defined in: providers/valueProviders.ts:215

Draws one value.

Parameters

random

RandomSource

Returns

number

---

FoliageAttachment

Defined in: features/tree/shared.ts:36

Where a foliage placer hangs its leaves, Java's FoliageAttachment.

Properties

foliageHeightOffset

readonly foliageHeightOffset: number

Defined in: features/tree/shared.ts:42

How much taller than the configured height this attachment's foliage is.

pos

readonly pos: BlockPos

Defined in: features/tree/shared.ts:38

The block the foliage grows around.

radiusOffsetXZ

readonly radiusOffsetXZ: number

Defined in: features/tree/shared.ts:40

How much wider than the configured radius this attachment's foliage is.

sizeX

readonly sizeX: number

Defined in: features/tree/shared.ts:44

The trunk's x extent at the attachment, 1 for a normal tree and 2 for a giant one.

sizeZ

readonly sizeZ: number

Defined in: features/tree/shared.ts:46

The trunk's z extent at the attachment.

---

FoliagePlacer

Defined in: features/tree/shared.ts:89

Lays out the leaves around an attachment, Java's FoliagePlacer.

Properties

type

readonly type: string

Defined in: features/tree/shared.ts:91

The registry name.

Methods

create()

create(context, treeHeight, entry, foliageHeight, leafRadius): void

Defined in: features/tree/shared.ts:97

Builds the leaves for one attachment.

Parameters

context

TreeContext

treeHeight

number

entry

FoliageAttachment

foliageHeight

number

leafRadius

number

Returns

void

foliageHeight()

foliageHeight(random, treeHeight): number

Defined in: features/tree/shared.ts:93

Draws how tall the foliage is.

Parameters

random

RandomSource

treeHeight

number

Returns

number

foliageRadius()

foliageRadius(random, trunkHeight): number

Defined in: features/tree/shared.ts:95

Draws how wide the foliage is.

Parameters

random

RandomSource

trunkHeight

number

Returns

number

---

GeodeConfig

Defined in: features/structural.ts:61

How a geode is shaped and what it is made of.

Properties

alternateInnerLayerProvider

readonly alternateInnerLayerProvider: BlockStateProvider

Defined in: features/structural.ts:64

baseCrackSize

readonly baseCrackSize: number

Defined in: features/structural.ts:75

cannotReplace

readonly cannotReplace: BlockSet

Defined in: features/structural.ts:68

crackPointOffset

readonly crackPointOffset: number

Defined in: features/structural.ts:76

distributionPoints

readonly distributionPoints: IntProvider

Defined in: features/structural.ts:81

filling

readonly filling: number

Defined in: features/structural.ts:70

fillingProvider

readonly fillingProvider: BlockStateProvider

Defined in: features/structural.ts:62

generateCrackChance

readonly generateCrackChance: number

Defined in: features/structural.ts:74

innerLayer

readonly innerLayer: number

Defined in: features/structural.ts:71

innerLayerProvider

readonly innerLayerProvider: BlockStateProvider

Defined in: features/structural.ts:63

innerPlacements

readonly innerPlacements: readonly BlockState[]

Defined in: features/structural.ts:67

invalidBlocks

readonly invalidBlocks: BlockSet

Defined in: features/structural.ts:69

invalidBlocksThreshold

readonly invalidBlocksThreshold: number

Defined in: features/structural.ts:86

maxGenOffset

readonly maxGenOffset: number

Defined in: features/structural.ts:84

middleLayer

readonly middleLayer: number

Defined in: features/structural.ts:72

middleLayerProvider

readonly middleLayerProvider: BlockStateProvider

Defined in: features/structural.ts:65

minGenOffset

readonly minGenOffset: number

Defined in: features/structural.ts:83

noiseMultiplier

readonly noiseMultiplier: number

Defined in: features/structural.ts:85

outerLayer

readonly outerLayer: number

Defined in: features/structural.ts:73

outerLayerProvider

readonly outerLayerProvider: BlockStateProvider

Defined in: features/structural.ts:66

outerWallDistance

readonly outerWallDistance: IntProvider

Defined in: features/structural.ts:80

placementsRequireLayer0Alternate

readonly placementsRequireLayer0Alternate: boolean

Defined in: features/structural.ts:79

pointOffset

readonly pointOffset: IntProvider

Defined in: features/structural.ts:82

useAlternateLayer0Chance

readonly useAlternateLayer0Chance: number

Defined in: features/structural.ts:78

usePotentialPlacementsChance

readonly usePotentialPlacementsChance: number

Defined in: features/structural.ts:77

---

HeightProvider

Defined in: providers/heightProvider.ts:73

A draw of one y, Java's HeightProvider.

It differs from an import('./valueProviders').IntProvider in taking a VerticalContext, because its bounds are anchors rather than numbers.

Properties

type

readonly type: HeightProviderType

Defined in: providers/heightProvider.ts:75

The provider's registry name.

Methods

sample()

sample(random, context): number

Defined in: providers/heightProvider.ts:77

Draws one y.

Parameters

random

RandomSource

context

VerticalContext

Returns

number

---

HugeMushroomConfig

Defined in: features/structural.ts:1105

How a huge mushroom is shaped.

Properties

canPlaceOn

readonly canPlaceOn: BlockPredicate

Defined in: features/structural.ts:1109

capProvider

readonly capProvider: BlockStateProvider

Defined in: features/structural.ts:1106

foliageRadius

readonly foliageRadius: number

Defined in: features/structural.ts:1108

stemProvider

readonly stemProvider: BlockStateProvider

Defined in: features/structural.ts:1107

---

IntProvider

Defined in: providers/valueProviders.ts:18

A draw of one integer, Java's IntProvider.

Counts, heights, radii and offsets throughout the feature data are providers rather than numbers, and the number of draws each one costs is part of the world's seed contract: a very_biased_to_bottom costs three draws where a uniform costs one, so substituting a distribution changes every value drawn after it.

Properties

maxValue

readonly maxValue: number

Defined in: providers/valueProviders.ts:24

The highest value the provider can return.

minValue

readonly minValue: number

Defined in: providers/valueProviders.ts:22

The lowest value the provider can return.

type

readonly type: IntProviderType

Defined in: providers/valueProviders.ts:20

The provider's registry name, for example uniform.

Methods

sample()

sample(random): number

Defined in: providers/valueProviders.ts:26

Draws one value, consuming the provider's fixed number of draws.

Parameters

random

RandomSource

Returns

number

---

LargeDripstoneConfig

Defined in: features/caves.ts:399

How a large dripstone is shaped.

Properties

columnRadius

readonly columnRadius: IntProvider

Defined in: features/caves.ts:402

floorToCeilingSearchRange

readonly floorToCeilingSearchRange: number

Defined in: features/caves.ts:401

heightScale

readonly heightScale: FloatProvider

Defined in: features/caves.ts:403

maxColumnRadiusToCaveHeightRatio

readonly maxColumnRadiusToCaveHeightRatio: number

Defined in: features/caves.ts:404

minBluntnessForWind

readonly minBluntnessForWind: number

Defined in: features/caves.ts:409

minRadiusForWind

readonly minRadiusForWind: number

Defined in: features/caves.ts:408

replaceableBlocks

readonly replaceableBlocks: BlockSet

Defined in: features/caves.ts:400

stalactiteBluntness

readonly stalactiteBluntness: FloatProvider

Defined in: features/caves.ts:405

stalagmiteBluntness

readonly stalagmiteBluntness: FloatProvider

Defined in: features/caves.ts:406

windSpeed

readonly windSpeed: FloatProvider

Defined in: features/caves.ts:407

---

PlacedFeature

Defined in: placement/pipeline.ts:43

A feature plus the modifier chain that decides where it goes, Java's PlacedFeature.

The 273 vanilla placed features are all of this shape: a reference to one of the 240 configured features and between zero and six modifiers.

Properties

feature

readonly feature: ConfiguredFeature

Defined in: placement/pipeline.ts:45

The feature placed at each position the chain produces.

placement

readonly placement: readonly PlacementModifier[]

Defined in: placement/pipeline.ts:47

The modifier chain, run in order.

---

PlacementContext

Defined in: placement/modifiers.ts:28

What a modifier is allowed to ask about the world while it transforms positions.

Properties

featureBelongsToBiome?

readonly optional featureBelongsToBiome?: (position) => boolean

Defined in: placement/modifiers.ts:38

Answers whether the placed feature being run is listed for the biome at a position, which is the whole of what minecraft:biome does.

The chunk generator supplies this, because the biome-to-feature table lives there. When a caller places one feature directly, the default accepts every position.

Parameters

position

BlockPos

Returns

boolean

world

readonly world: FeatureWorld

Defined in: placement/modifiers.ts:30

The world being decorated.

---

PlacementModifier

Defined in: placement/modifiers.ts:47

One stage of a placed feature's pipeline, Java's PlacementModifier.

A modifier takes one position and emits zero, one or many. Filters emit zero or one, spreads emit one moved, and counts emit the same position several times. The pipeline composes them.

Properties

type

readonly type: PlacementModifierTypeName

Defined in: placement/modifiers.ts:49

The modifier's registry name.

Methods

modify()

modify(context, random, origin, output): void

Defined in: placement/modifiers.ts:51

Transforms one position, pushing each result to output.

Parameters

context

PlacementContext

random

RandomSource

origin

BlockPos

output

(position) => void

Returns

void

---

RootPlacer

Defined in: features/tree/shared.ts:107

Lays out the roots below the trunk, Java's RootPlacer.

Properties

type

readonly type: "mangrove_root_placer"

Defined in: features/tree/shared.ts:109

The registry name.

Methods

place()

place(context, origin, trunkOrigin): boolean

Defined in: features/tree/shared.ts:113

Builds the roots. Returns false to abandon the whole tree.

Parameters

context

TreeContext

origin

BlockPos

trunkOrigin

BlockPos

Returns

boolean

trunkOrigin()

trunkOrigin(origin, random): BlockPos

Defined in: features/tree/shared.ts:111

Returns where the trunk starts, which a root placer raises above the origin.

Parameters

origin

BlockPos

random

RandomSource

Returns

BlockPos

---

RootSystemConfig

Defined in: features/structural.ts:670

How a root system is shaped.

Properties

allowedTreePosition

readonly allowedTreePosition: BlockPredicate

Defined in: features/structural.ts:685

allowedVerticalWaterForTree

readonly allowedVerticalWaterForTree: number

Defined in: features/structural.ts:684

hangingRootPlacementAttempts

readonly hangingRootPlacementAttempts: number

Defined in: features/structural.ts:683

hangingRootRadius

readonly hangingRootRadius: number

Defined in: features/structural.ts:680

hangingRootStateProvider

readonly hangingRootStateProvider: BlockStateProvider

Defined in: features/structural.ts:682

hangingRootsVerticalSpan

readonly hangingRootsVerticalSpan: number

Defined in: features/structural.ts:681

levelTestDistance

readonly levelTestDistance: number

Defined in: features/structural.ts:673

maxLevelDeviation

readonly maxLevelDeviation: number

Defined in: features/structural.ts:674

requiredVerticalSpaceForTree

readonly requiredVerticalSpaceForTree: number

Defined in: features/structural.ts:672

rootColumnMaxHeight

readonly rootColumnMaxHeight: number

Defined in: features/structural.ts:679

rootPlacementAttempts

readonly rootPlacementAttempts: number

Defined in: features/structural.ts:678

rootRadius

readonly rootRadius: number

Defined in: features/structural.ts:675

rootReplaceable

readonly rootReplaceable: BlockSet

Defined in: features/structural.ts:676

rootStateProvider

readonly rootStateProvider: BlockStateProvider

Defined in: features/structural.ts:677

treeFeature

readonly treeFeature: PlacedFeature

Defined in: features/structural.ts:671

---

ScannedColumn

Defined in: features/caves.ts:45

A scanned column: the first non-matching block below and above the origin.

Properties

ceiling?

readonly optional ceiling?: number

Defined in: features/caves.ts:49

The y of the first block above the origin that fails inside, when there is one.

floor?

readonly optional floor?: number

Defined in: features/caves.ts:47

The y of the first block below the origin that fails inside, when there is one.

height?

readonly optional height?: number

Defined in: features/caves.ts:51

How many inside blocks sit strictly between the floor and the ceiling.

---

ScheduledFeature

Defined in: placement/pipeline.ts:100

One entry of a chunk's decoration plan: a placed feature, its step and its index in that step.

Properties

feature

readonly feature: PlacedFeature

Defined in: placement/pipeline.ts:102

The placed feature to run.

index

readonly index: number

Defined in: placement/pipeline.ts:112

The feature's index within the step's flattened, de-duplicated feature list.

Java builds one list per step across every biome in the world, so the index is global to the dimension rather than local to the chunk or the biome. Two chunks in different biomes therefore seed the same feature identically.

step

readonly step: "lakes" | "raw_generation" | "local_modifications" | "underground_structures" | "surface_structures" | "strongholds" | "underground_ores" | "underground_decoration" | "fluid_springs" | "vegetal_decoration" | "top_layer_modification"

Defined in: placement/pipeline.ts:104

The decoration step it belongs to.

---

SpeleothemClusterConfig

Defined in: features/caves.ts:201

How a speleothem cluster is shaped.

Properties

baseBlock

readonly baseBlock: string

Defined in: features/caves.ts:202

chanceOfSpeleothemAtMaxDistanceFromCenter

readonly chanceOfSpeleothemAtMaxDistanceFromCenter: number

Defined in: features/caves.ts:213

density

readonly density: FloatProvider

Defined in: features/caves.ts:211

floorToCeilingSearchRange

readonly floorToCeilingSearchRange: number

Defined in: features/caves.ts:205

height

readonly height: IntProvider

Defined in: features/caves.ts:206

heightDeviation

readonly heightDeviation: number

Defined in: features/caves.ts:209

maxDistanceFromCenterAffectingHeightBias

readonly maxDistanceFromCenterAffectingHeightBias: number

Defined in: features/caves.ts:215

maxDistanceFromEdgeAffectingChanceOfSpeleothem

readonly maxDistanceFromEdgeAffectingChanceOfSpeleothem: number

Defined in: features/caves.ts:214

maxStalagmiteStalactiteHeightDiff

readonly maxStalagmiteStalactiteHeightDiff: number

Defined in: features/caves.ts:208

pointedBlock

readonly pointedBlock: string

Defined in: features/caves.ts:203

radius

readonly radius: IntProvider

Defined in: features/caves.ts:207

replaceableBlocks

readonly replaceableBlocks: BlockSet

Defined in: features/caves.ts:204

speleothemBlockLayerThickness

readonly speleothemBlockLayerThickness: IntProvider

Defined in: features/caves.ts:210

wetness

readonly wetness: FloatProvider

Defined in: features/caves.ts:212

---

SteppedColumnClusterConfig

Defined in: features/caves.ts:685

How a stepped column cluster is shaped.

Properties

block

readonly block: BlockStateProvider

Defined in: features/caves.ts:686

cannotPlaceOn

readonly cannotPlaceOn: BlockSet

Defined in: features/caves.ts:689

canReplace

readonly canReplace: BlockPredicate

Defined in: features/caves.ts:688

clusterReach

readonly clusterReach: IntProvider

Defined in: features/caves.ts:690

columnCount

readonly columnCount: IntProvider

Defined in: features/caves.ts:691

columnReach

readonly columnReach: IntProvider

Defined in: features/caves.ts:692

continueThrough

readonly continueThrough: BlockPredicate

Defined in: features/caves.ts:687

height

readonly height: IntProvider

Defined in: features/caves.ts:693

---

TargetWorld

Defined in: world/FeatureWorld.ts:237

A world that stores some other state type, which translatingWorld adapts.

Extends

• Omit<FeatureWorld, "getBlock" | "setBlock" | "blocks">

Type Parameters

Target

Target

Properties

height

readonly height: number

Defined in: world/FeatureWorld.ts:97

The number of y levels the dimension generates, Java's getHeight().

Inherited from

FeatureWorld.height

isColdEnoughToSnow?

optional isColdEnoughToSnow?: (position) => boolean

Defined in: world/FeatureWorld.ts:125

Answers Java's Biome.getTemperature(pos) < 0.15, which is the whole of what decides whether freeze_top_layer acts.

Optional, because biome climate lives in the biome source rather than here. When absent nothing freezes, which is the right answer for a warm world and a visible one for a cold world rather than a silent miss.

Parameters

position

BlockPos

Returns

boolean

Inherited from

FeatureWorld.isColdEnoughToSnow

minY

readonly minY: number

Defined in: world/FeatureWorld.ts:95

The lowest y the dimension generates, Java's getMinY().

Inherited from

FeatureWorld.minY

placeTemplate?

optional placeTemplate?: (request) => boolean

Defined in: world/FeatureWorld.ts:141

Places a structure template, which template and fossil delegate to.

Optional, and the seam to @jsprismarine/structures: this package names a template and a processor list and does not read NBT. A world that cannot place one reports failure, which propagates through the pipeline the same way an obstructed placement does.

Parameters

request

TemplateRequest

Returns

boolean

Inherited from

FeatureWorld.placeTemplate

seaLevel

readonly seaLevel: number

Defined in: world/FeatureWorld.ts:99

The dimension's sea level, which relative_to_sea_level anchors resolve against.

Inherited from

FeatureWorld.seaLevel

seed

readonly seed: bigint

Defined in: world/FeatureWorld.ts:106

The world seed.

Only the geode reads it, to build a noise field that is the same everywhere in one world and different between worlds.

Inherited from

FeatureWorld.seed

setBlockEntity?

optional setBlockEntity?: (position, data) => void

Defined in: world/FeatureWorld.ts:133

Attaches block entity data to a block this package just wrote.

Optional, because only six features need it: the two chests, the spawner, the two end gateway kinds and the end podium. A world that cannot store it loses the contents rather than the block.

Parameters

position

BlockPos

data

BlockEntityRequest

Returns

void

Inherited from

FeatureWorld.setBlockEntity

spawnEntity?

optional spawnEntity?: (identifier, position, options?) => void

Defined in: world/FeatureWorld.ts:147

Spawns an entity a feature builds around, which is only the end spike's crystal.

Optional, because entities belong to the server rather than to world generation.

Parameters

identifier

string

position

BlockPos

options?

EntitySpawnOptions

Returns

void

Inherited from

FeatureWorld.spawnEntity

Methods

getBiome()

getBiome(position): string

Defined in: world/FeatureWorld.ts:116

Returns the biome identifier at a position.

Parameters

position

BlockPos

Returns

string

Inherited from

FeatureWorld.getBiome

getBlock()

getBlock(position): Target

Defined in: world/FeatureWorld.ts:238

Parameters

position

BlockPos

Returns

Target

getHeight()

getHeight(heightmap, x, z): number

Defined in: world/FeatureWorld.ts:114

Returns the first y above the topmost block matching the heightmap's predicate.

Parameters

heightmap

HeightmapType

x

number

z

number

Returns

number

Inherited from

FeatureWorld.getHeight

setBlock()

setBlock(position, state): boolean

Defined in: world/FeatureWorld.ts:239

Parameters

position

BlockPos

state

Target

Returns

boolean

---

TemplateRequest

Defined in: world/FeatureWorld.ts:200

What a feature asks a world to stamp out of a structure template.

Properties

mirror

readonly mirror: "none" | "left_right" | "front_back"

Defined in: world/FeatureWorld.ts:208

The mirror to apply before the rotation.

offset?

readonly optional offset?: BlockPos

Defined in: world/FeatureWorld.ts:212

The template's own offset, which template carries as offset.

origin

readonly origin: BlockPos

Defined in: world/FeatureWorld.ts:204

Where the template's origin corner lands.

overwrite?

readonly optional overwrite?: boolean

Defined in: world/FeatureWorld.ts:216

Whether air in the template overwrites the world.

processors?

readonly optional processors?: TemplateProcessors

Defined in: world/FeatureWorld.ts:210

The processors to run over the template, when the feature carries any.

projectToHeightmap?

readonly optional projectToHeightmap?: HeightmapType

Defined in: world/FeatureWorld.ts:214

Whether the template's project-to-heightmap mode is set, and to which heightmap.

rotation

readonly rotation: number

Defined in: world/FeatureWorld.ts:206

The quarter turns to apply, 0 through 3.

template

readonly template: string

Defined in: world/FeatureWorld.ts:202

The template identifier, for example minecraft:trail_ruins/tower/tower_top.

---

TestFeatureWorldOptions

Defined in: world/TestFeatureWorld.ts:71

How a test world is sized and what it knows about blocks.

Properties

biome?

readonly optional biome?: string

Defined in: world/TestFeatureWorld.ts:79

The biome every position reports. Defaults to minecraft:plains.

blocks?

readonly optional blocks?: BlockOracle

Defined in: world/TestFeatureWorld.ts:83

The block facts. Defaults to createTestOracle with no tables.

height?

readonly optional height?: number

Defined in: world/TestFeatureWorld.ts:75

The number of generated y levels. Defaults to 384, the overworld's.

minY?

readonly optional minY?: number

Defined in: world/TestFeatureWorld.ts:73

The lowest generated y. Defaults to -64, the overworld's.

seaLevel?

readonly optional seaLevel?: number

Defined in: world/TestFeatureWorld.ts:77

The sea level relative_to_sea_level resolves against. Defaults to 63.

seed?

readonly optional seed?: bigint

Defined in: world/TestFeatureWorld.ts:81

The world seed. Defaults to zero.

---

TestOracleTables

Defined in: world/TestFeatureWorld.ts:10

What a caller may declare about the blocks a test uses.

Properties

air?

readonly optional air?: readonly string[]

Defined in: world/TestFeatureWorld.ts:12

Identifiers that count as air. Defaults to the three vanilla air blocks.

canSurvive?

readonly optional canSurvive?: (world, position, state) => boolean

Defined in: world/TestFeatureWorld.ts:22

Overrides canSurvive. The default asks whether the block below is solid.

Parameters

world

FeatureWorld

position

BlockPos

state

BlockState

Returns

boolean

fluids?

readonly optional fluids?: Readonly<Record<string, FluidKind>>

Defined in: world/TestFeatureWorld.ts:14

Identifiers that hold a fluid, and which one. Waterlogged states are detected separately.

nonSolid?

readonly optional nonSolid?: readonly string[]

Defined in: world/TestFeatureWorld.ts:18

Identifiers that do not fill their cell. Everything else is solid and sturdy on every face.

replaceable?

readonly optional replaceable?: readonly string[]

Defined in: world/TestFeatureWorld.ts:16

Identifiers a feature may overwrite. Air and fluids are always replaceable.

tags?

readonly optional tags?: Readonly<Record<string, readonly string[]>>

Defined in: world/TestFeatureWorld.ts:20

Tag membership, keyed by tag identifier with no leading #.

---

TreeConfig

Defined in: features/tree/shared.ts:141

A parsed minecraft:tree configuration.

Properties

belowTrunkProvider

readonly belowTrunkProvider: BlockStateProvider

Defined in: features/tree/shared.ts:159

What the trunk puts into the block it stands on.

decorators

readonly decorators: readonly TreeDecorator[]

Defined in: features/tree/shared.ts:155

What is added after the trunk and foliage.

foliagePlacer

readonly foliagePlacer: FoliagePlacer

Defined in: features/tree/shared.ts:149

The foliage layout.

foliageProvider

readonly foliageProvider: BlockStateProvider

Defined in: features/tree/shared.ts:147

The leaf the foliage is made of.

ignoreVines

readonly ignoreVines: boolean

Defined in: features/tree/shared.ts:157

Whether a vine in the way stops the tree.

minimumSize

readonly minimumSize: FeatureSize

Defined in: features/tree/shared.ts:153

How much room the tree needs.

rootPlacer?

readonly optional rootPlacer?: RootPlacer

Defined in: features/tree/shared.ts:151

The root layout, when the tree has roots.

trunkPlacer

readonly trunkPlacer: TrunkPlacer

Defined in: features/tree/shared.ts:145

The trunk layout.

trunkProvider

readonly trunkProvider: BlockStateProvider

Defined in: features/tree/shared.ts:143

The log the trunk is made of.

---

TreeContext

Defined in: features/tree/shared.ts:18

Everything a placer needs from the tree it belongs to.

Properties

config

readonly config: TreeConfig

Defined in: features/tree/shared.ts:24

The tree's configuration.

random

readonly random: RandomSource

Defined in: features/tree/shared.ts:22

The stream every draw comes from.

world

readonly world: FeatureWorld

Defined in: features/tree/shared.ts:20

The world being built into.

Methods

hasFoliage()

hasFoliage(position): boolean

Defined in: features/tree/shared.ts:32

Answers whether a leaf was already placed here by this tree.

Parameters

position

BlockPos

Returns

boolean

setFoliage()

setFoliage(position, state): void

Defined in: features/tree/shared.ts:30

Records a leaf.

Parameters

position

BlockPos

state

BlockState

Returns

void

setRoot()

setRoot(position, state): void

Defined in: features/tree/shared.ts:28

Records a root.

Parameters

position

BlockPos

state

BlockState

Returns

void

setTrunk()

setTrunk(position, state): void

Defined in: features/tree/shared.ts:26

Records a log or a root.

Parameters

position

BlockPos

state

BlockState

Returns

void

---

TreeDecorator

Defined in: features/tree/shared.ts:117

Adds the hives, vines, mushrooms and ground cover a tree carries, Java's TreeDecorator.

Properties

type

readonly type: string

Defined in: features/tree/shared.ts:119

The registry name.

Methods

place()

place(context): void

Defined in: features/tree/shared.ts:121

Runs over the finished tree.

Parameters

context

DecoratorContext

Returns

void

---

TrunkPlacer

Defined in: features/tree/shared.ts:77

Lays out the trunk and reports where the foliage attaches, Java's TrunkPlacer.

Properties

type

readonly type: string

Defined in: features/tree/shared.ts:79

The registry name.

Methods

isFree()

isFree(world, position): boolean

Defined in: features/tree/shared.ts:85

Answers whether a position does not block the trunk, which the free-height scan reads.

Parameters

world

FeatureWorld

position

BlockPos

Returns

boolean

place()

place(context, treeHeight, origin): FoliageAttachment[]

Defined in: features/tree/shared.ts:83

Builds the trunk and returns the foliage attachments.

Parameters

context

TreeContext

treeHeight

number

origin

BlockPos

Returns

FoliageAttachment[]

treeHeight()

treeHeight(random): number

Defined in: features/tree/shared.ts:81

Draws the tree's total height.

Parameters

random

RandomSource

Returns

number

---

VegetationPatchConfig

Defined in: features/caves.ts:542

How a vegetation patch is shaped.

Properties

depth

readonly depth: IntProvider

Defined in: features/caves.ts:547

extraBottomBlockChance

readonly extraBottomBlockChance: number

Defined in: features/caves.ts:548

extraEdgeColumnChance

readonly extraEdgeColumnChance: number

Defined in: features/caves.ts:552

groundState

readonly groundState: BlockStateProvider

Defined in: features/caves.ts:544

replaceable

readonly replaceable: BlockSet

Defined in: features/caves.ts:543

surface

readonly surface: "floor" | "ceiling"

Defined in: features/caves.ts:546

vegetationChance

readonly vegetationChance: number

Defined in: features/caves.ts:550

vegetationFeature

readonly vegetationFeature: PlacedFeature

Defined in: features/caves.ts:545

verticalRange

readonly verticalRange: number

Defined in: features/caves.ts:549

xzRadius

readonly xzRadius: IntProvider

Defined in: features/caves.ts:551

---

VerticalContext

Defined in: providers/heightProvider.ts:15

What a height provider needs from the dimension to turn an anchor into a y.

It is the three numbers of Java's WorldGenerationContext, so a caller can resolve a height without a world.

Properties

height

readonly height: number

Defined in: providers/heightProvider.ts:19

The number of generated y levels.

minY

readonly minY: number

Defined in: providers/heightProvider.ts:17

The lowest generated y.

seaLevel

readonly seaLevel: number

Defined in: providers/heightProvider.ts:21

The dimension's sea level.

---

Weighted

Defined in: placement/WorldgenRandom.ts:255

An entry in a Java WeightedList.

Type Parameters

T

T

Properties

value

readonly value: T

Defined in: placement/WorldgenRandom.ts:256

weight

readonly weight: number

Defined in: placement/WorldgenRandom.ts:257

---

WorldgenRandomState

Defined in: placement/WorldgenRandom.ts:14

JSON-safe continuation state for Java's reseedable world-generation stream.

Properties

algorithm

readonly algorithm: WorldgenRandomAlgorithm

Defined in: placement/WorldgenRandom.ts:16

delegate

readonly delegate: LegacyRandomSourceState | XoroshiroRandomSourceState

Defined in: placement/WorldgenRandom.ts:17

gaussian

readonly gaussian: GaussianCacheState

Defined in: placement/WorldgenRandom.ts:18

version

readonly version: 1

Defined in: placement/WorldgenRandom.ts:15

Type Aliases

BlockPredicate

BlockPredicate = (world, position) => boolean

Defined in: providers/blockPredicate.ts:17

A test on one world position, Java's BlockPredicate.

Predicates gate placement (block_predicate_filter), stop a scan (environment_scan) and decide what a feature may overwrite. They draw no randomness, so running one costs nothing against the seed and a feature can test freely.

Parameters

world

FeatureWorld

position

BlockPos

Returns

boolean

---

BlockPredicateTypeName

BlockPredicateTypeName = "matching_blocks" | "matching_block_tag" | "matching_fluids" | "matching_biomes" | "has_sturdy_face" | "solid" | "replaceable" | "would_survive" | "inside_world_bounds" | "any_of" | "all_of" | "not" | "true" | "unobstructed" | "height_range" | "volume_match"

Defined in: providers/blockPredicate.ts:20

The sixteen types Java 26.3 registers in block_predicate_type.

---

BlockSet

BlockSet = { kind: "tag"; tag: string; } | { kind: "blocks"; names: readonly string[]; }

Defined in: registry.ts:36

A reference to a set of blocks: either one identifier or a #-prefixed tag.

Java's HolderSet also accepts an inline list; features_cannot_replace and the geode's invalid-block set are the two shapes the vanilla feature data actually uses.

---

BlockStateMapper

BlockStateMapper<Target> = object

Defined in: world/FeatureWorld.ts:229

Translates the Java block states a feature writes into whatever the target world stores.

A server supplies @jsprismarine/mapping's Java-to-Bedrock function here. Nothing in this package knows that two editions exist.

Type Parameters

Target

Target

Methods

toJava()

toJava(state): BlockState

Defined in: world/FeatureWorld.ts:233

Converts a target state back into Java, so predicates and reads keep working.

Parameters

state

Target

Returns

BlockState

toTarget()

toTarget(state): Target

Defined in: world/FeatureWorld.ts:231

Converts a Java state into the target world's state type.

Parameters

state

BlockState

Returns

Target

---

BlockStateProviderResolver

BlockStateProviderResolver = (id, path) => BlockStateProvider

Defined in: providers/blockStateProvider.ts:243

Resolves a worldgen/block_state_provider reference to its parsed provider.

Parameters

id

string

path

string

Returns

BlockStateProvider

---

BlockStateProviderTypeName

BlockStateProviderTypeName = "simple" | "weighted" | "noise" | "dual_noise" | "noise_threshold" | "randomized_int" | "rotated" | "rule_based" | "random_block" | "copy_properties"

Defined in: providers/blockStateProvider.ts:36

The ten types Java 26.3 registers in worldgen/block_state_provider_type.

---

DecorationStep

DecorationStep = typeof DECORATION_STEPS[number]

Defined in: placement/pipeline.ts:32

One of the eleven decoration steps.

---

Direction

Direction = "down" | "up" | "north" | "south" | "west" | "east"

Defined in: world/BlockState.ts:20

The six block faces, spelled as Java spells a Direction.

---

FeatureTypeName

FeatureTypeName = typeof FEATURE_TYPES[number]

Defined in: features/Feature.ts:68

One of the 58 registered feature types.

---

FeatureTypeUsage

FeatureTypeUsage = ReadonlyMap<FeatureTypeName, number>

Defined in: features/parse.ts:169

A feature type and how many of the parsed documents used it.

---

FloatProviderType

FloatProviderType = "constant" | "uniform" | "trapezoid" | "clamped_normal"

Defined in: providers/valueProviders.ts:219

The four types Java 26.3 registers in float_provider_type.

---

FluidKind

FluidKind = "empty" | "water" | "lava"

Defined in: world/BlockState.ts:17

The three fluids a block state can hold, which is all the feature code distinguishes.

---

HeightProviderType

HeightProviderType = "constant" | "uniform" | "biased_to_bottom" | "very_biased_to_bottom" | "trapezoid" | "weighted_list"

Defined in: providers/heightProvider.ts:81

The six types Java 26.3 registers in height_provider_type.

---

HeightmapType

HeightmapType = "WORLD_SURFACE_WG" | "WORLD_SURFACE" | "OCEAN_FLOOR_WG" | "OCEAN_FLOOR" | "MOTION_BLOCKING" | "MOTION_BLOCKING_NO_LEAVES"

Defined in: world/FeatureWorld.ts:32

The six heightmaps Java Edition keeps, named as the placement JSON spells them.

The three _WG and OCEAN_FLOOR/WORLD_SURFACE pairs differ only in when they are computed, so a generator that decorates a chunk once can answer both from the same column scan.

---

IntProviderType

IntProviderType = "constant" | "uniform" | "biased_to_bottom" | "very_biased_to_bottom" | "trapezoid" | "clamped" | "clamped_normal" | "weighted_list"

Defined in: providers/valueProviders.ts:30

The eight types Java 26.3 registers in int_provider_type.

---

PlacementModifierTypeName

PlacementModifierTypeName = "block_predicate_filter" | "rarity_filter" | "random_chance" | "surface_relative_threshold_filter" | "surface_water_depth_filter" | "biome" | "count" | "noise_based_count" | "noise_threshold_count" | "count_on_every_layer" | "cuboid" | "environment_scan" | "heightmap" | "height_range" | "in_square" | "offset" | "randomly_selected" | "fixed_placement"

Defined in: placement/modifiers.ts:60

The eighteen types Java 26.3 registers in worldgen/placement_modifier_type.

---

RuleTest

RuleTest = (blocks, state, position, random) => boolean

Defined in: features/ruleTest.ts:18

A test on a block state and its position, Java's RuleTest.

Ores use these to decide what they may cut through, which is why ore_diamond can place deepslate diamond below y 8 and ordinary diamond above it from one feature. Unlike a import('../providers/blockPredicate').BlockPredicate it never reads the world: it is handed the state it is judging, and two of the ten types draw from the random stream.

Parameters

blocks

BlockOracle

state

BlockState

position

BlockPos

random

RandomSource

Returns

boolean

---

RuleTestTypeName

RuleTestTypeName = "always_true" | "block_match" | "blockstate_match" | "tag_match" | "random_block_match" | "random_blockstate_match" | "height_match" | "not" | "any_of" | "all_of"

Defined in: features/ruleTest.ts:21

The ten types Java 26.3 registers in rule_test.

---

TemplateProcessors

TemplateProcessors = string | { processors: readonly unknown[]; }

Defined in: world/FeatureWorld.ts:197

The processors a feature runs its template through.

Java's field is either an identifier naming a worldgen/processor_list or the list itself, written where the feature stands. The inline form stays unknown here, because this package names a chain and does not read one. The world parses whichever form arrives.

---

VerticalAnchor

VerticalAnchor = { kind: "absolute"; y: number; } | { kind: "above_bottom"; offset: number; } | { kind: "below_top"; offset: number; } | { kind: "relative_to_sea_level"; offset: number; }

Defined in: providers/heightProvider.ts:30

One end of a vertical range, Java's VerticalAnchor.

The four forms exist so a datapack can express "eight above the bottom of whatever dimension this is" without knowing the dimension's height.

---

VerticalDirection

VerticalDirection = "down" | "up"

Defined in: world/BlockState.ts:23

The two vertical directions, which environment_scan and the speleothem features search along.

---

WorldgenRandomAlgorithm

WorldgenRandomAlgorithm = "xoroshiro" | "legacy"

Defined in: placement/WorldgenRandom.ts:11

Which generator backs a WorldgenRandom. The decoration pass uses Xoroshiro.

Variables

AIR

const AIR: BlockState

Defined in: world/TestFeatureWorld.ts:7

The state every unwritten position holds.

---

ALL_DIRECTIONS

const ALL_DIRECTIONS: readonly ["down", "up", "north", "south", "west", "east"]

Defined in: world/BlockState.ts:45

Every direction in Java's declaration order, which decides iteration order in several features.

---

BIOME_INFO_NOISE

const BIOME_INFO_NOISE: SimplexNoise

Defined in: placement/modifiers.ts:25

The noise Java samples for noise_based_count and noise_threshold_count.

It is Biome.BIOME_INFO_NOISE: one simplex octave seeded from 2345 with its coordinate offsets discarded, shared by every world regardless of seed. That is why a flower field sits in the same place in every world, and it is the one part of the decoration pass that is not keyed off the world seed at all.

---

DECORATION_STEPS

const DECORATION_STEPS: readonly ["raw_generation", "lakes", "local_modifications", "underground_structures", "surface_structures", "strongholds", "underground_ores", "underground_decoration", "fluid_springs", "vegetal_decoration", "top_layer_modification"]

Defined in: placement/pipeline.ts:17

The eleven decoration steps, in the order Java runs them.

The order is part of the world's contract rather than a detail: lakes carve before local modifications fill them, ores cut through both, and vegetation lands on whatever the earlier steps left. A biome's features field is a list of eleven lists in exactly this order.

---

DIRECTION_STEPS

const DIRECTION_STEPS: Readonly<Record<Direction, readonly [number, number, number]>>

Defined in: world/BlockState.ts:26

The unit step of each direction, in Java's axis order.

---

FEATURE_TYPES

const FEATURE_TYPES: readonly ["bamboo", "block_blob", "block_column", "block_pile", "blue_ice", "bonus_chest", "chorus_plant", "coral_claw", "coral_tree", "delta_feature", "disk", "end_gateway", "end_island", "end_platform", "end_podium", "end_spike", "fallen_tree", "fill_layer", "fossil", "freeze_top_layer", "geode", "huge_brown_mushroom", "huge_fungus", "huge_red_mushroom", "iceberg", "lake", "large_dripstone", "monster_room", "multiface_growth", "netherrack_replace_blobs", "no_op", "ore", "overlay", "projected_random_patchy_square", "random_boolean_selector", "random_neighbor_spread", "random_selector", "replace_single_block", "root_system", "scattered_ore", "sculk_patch", "sequence", "simple_block", "simple_random_selector", "single_block_pillar", "speleothem", "speleothem_cluster", "spike", "spring_feature", "stepped_column_cluster", "template", "tree", "underwater_magma", "vegetation_patch", "vines", "void_start_platform", "waterlogged_vegetation_patch", "weighted_random_selector"]

Defined in: features/Feature.ts:6

The 58 feature types Java 26.3 registers in worldgen/feature_type.

---

HORIZONTAL_DIRECTIONS

const HORIZONTAL_DIRECTIONS: readonly ["north", "east", "south", "west"]

Defined in: world/BlockState.ts:42

The four compass directions in Java's Direction.Plane.HORIZONTAL order.

This is north, east, south, west, which is not the order of Direction.values(). Anything that draws a random horizontal direction indexes into this array, so the order is part of the seed contract rather than a presentation detail.

---

alwaysTrue

const alwaysTrue: BlockPredicate

Defined in: providers/blockPredicate.ts:39

The predicate that accepts everything, which several optional fields default to.

---

noOpFeature

const noOpFeature: ConfiguredFeature

Defined in: features/Feature.ts:99

The feature that does nothing, which selectors use as a weighted "place nothing" branch.

---

structuralInternals

const structuralInternals: object

Defined in: features/structural.ts:1705

Exported for the corpus test, which reports how many states a geode's inner placements hold.

Type Declaration

mthCos

mthCos: (value) => number

Java's Mth.cos, the same table a quarter turn along.

Parameters

value

number

Returns

number

mthSin

mthSin: (value) => number

Java's Mth.sin, which reads a 65536-entry float table rather than calling Math.sin.

The two differ by up to about 5e-5, which is enough to move an ore vein's sphere radii across a block boundary, so worldgen code that calls Mth.sin has to call this and code that calls java.lang.Math.sin has to call Math.sin.

Parameters

value

number

Returns

number

PACKED_ICE

PACKED_ICE: BlockState

parseStateList

parseStateList: (source, path) => BlockState[]

Parameters

source

unknown

path

string

Returns

BlockState[]

---

treeInternals

const treeInternals: object

Defined in: features/tree.ts:135

Exposed for the sibling fallen_tree feature, which reuses the trunk and decorator parsers.

Type Declaration

constantInt

constantInt: (value) => IntProvider

A constant. Costs no draws.

Parameters

value

number

Returns

IntProvider

parseTreeDecorator

parseTreeDecorator: (source, path, parsers) => TreeDecorator

Parses one decorators entry into the matching decorator.

Parameters

source

unknown

path

string

parsers

FeatureParsers

Returns

TreeDecorator

parseTrunkPlacer

parseTrunkPlacer: (source, path) => TrunkPlacer

Parses a trunk_placer body into the matching placer.

Parameters

source

unknown

path

string

Returns

TrunkPlacer

placeLog

placeLog: (context, position, modify) => boolean

Places a trunk block from the trunk provider where the tree may grow; returns whether it did.

Parameters

context

TreeContext

position

BlockPos

modify?

(state) => BlockState

Returns

boolean

validTreePos

validTreePos: (world, position) => boolean

Answers Java's TreeFeature.validTreePos: air, or a block trees are allowed to grow through.

Parameters

world

FeatureWorld

position

BlockPos

Returns

boolean

Functions

above()

above(position, distance?): BlockPos

Defined in: features/support.ts:16

Returns the position one block up.

Parameters

position

BlockPos

distance?

number = 1

Returns

BlockPos

---

asArray()

asArray(value, path): unknown[]

Defined in: json.ts:25

Reads a JSON array.

Parameters

value

unknown

path

string

Returns

unknown[]

---

asBoolean()

asBoolean(value, path, fallback?): boolean

Defined in: json.ts:47

Reads a boolean, with an optional fallback for a missing field.

Parameters

value

unknown

path

string

fallback?

boolean

Returns

boolean

---

asEnum()

asEnum<T>(value, allowed, path): T

Defined in: json.ts:61

Reads a string that must be one of a known set, narrowing it to that union.

Type Parameters

T

T extends string

Parameters

value

unknown

allowed

readonly T[]

path

string

Returns

T

---

asInteger()

asInteger(value, path, fallback?): number

Defined in: json.ts:40

Reads an integer, with an optional fallback for a missing field.

Parameters

value

unknown

path

string

fallback?

number

Returns

number

---

asNumber()

asNumber(value, path, fallback?): number

Defined in: json.ts:31

Reads a finite number, with an optional fallback for a missing field.

Parameters

value

unknown

path

string

fallback?

number

Returns

number

---

asObject()

asObject(value, path): Record<string, unknown>

Defined in: json.ts:16

Reads a JSON object.

Parameters

value

unknown

path

string

Returns

Record<string, unknown>

---

asString()

asString(value, path, fallback?): string

Defined in: json.ts:54

Reads a string, with an optional fallback for a missing field.

Parameters

value

unknown

path

string

fallback?

string

Returns

string

---

atY()

atY(origin, y): BlockPos

Defined in: world/FeatureWorld.ts:21

Returns origin with a different y.

Parameters

origin

BlockPos

y

number

Returns

BlockPos

---

bamboo()

bamboo(probability): ConfiguredFeature

Defined in: features/structural.ts:774

A bamboo stalk with its podzol disc, Java's bamboo.

Parameters

probability

number

Returns

ConfiguredFeature

---

below()

below(position, distance?): BlockPos

Defined in: features/support.ts:19

Returns the position one block down.

Parameters

position

BlockPos

distance?

number = 1

Returns

BlockPos

---

betweenClosed()

betweenClosed(from, to): Generator<BlockPos>

Defined in: features/support.ts:58

Iterates every position of an inclusive box, in Java's BlockPos.betweenClosed order.

Parameters

from

BlockPos

to

BlockPos

Returns

Generator<BlockPos>

---

biasedToBottomHeight()

biasedToBottomHeight(min, max, inner): HeightProvider

Defined in: providers/heightProvider.ts:106

A y weighted toward the bottom of [min + inner, max]. Costs two draws.

Parameters

min

VerticalAnchor

max

VerticalAnchor

inner

number

Returns

HeightProvider

---

biasedToBottomInt()

biasedToBottomInt(min, max): IntProvider

Defined in: providers/valueProviders.ts:60

A value in [min, max] weighted toward min. Costs two draws.

Parameters

min

number

max

number

Returns

IntProvider

---

biomeFilter()

biomeFilter(): PlacementModifier

Defined in: placement/modifiers.ts:157

Keeps the position when the placed feature is listed for the biome there.

Java throws when a feature reaches this modifier without having been looked up through a biome, because placing it anyway would ignore the biome's own list. This reproduces that: a context with no biome table accepts everything, and the chunk generator always supplies one.

Returns

PlacementModifier

---

blockBlob()

blockBlob(state, canPlaceOn): ConfiguredFeature

Defined in: features/simple.ts:444

Drops three overlapping blobs of one state onto the first block that passes a predicate.

Parameters

state

BlockState

canPlaceOn

BlockPredicate

Returns

ConfiguredFeature

---

blockColumn()

blockColumn(layers, direction, allowedPlacement, prioritizeTip): ConfiguredFeature

Defined in: features/simple.ts:728

Stacks several bands of blocks in one direction, trimming them when the column runs into something.

Which end gets trimmed is prioritize_tip: a twisting vine keeps its tip and loses its stem, while a kelp column keeps its stem and loses its tip.

Parameters

layers

readonly BlockColumnLayer[]

direction

Direction

allowedPlacement

BlockPredicate

prioritizeTip

boolean

Returns

ConfiguredFeature

---

blockPile()

blockPile(stateProvider): ConfiguredFeature

Defined in: features/simple.ts:416

Scatters blocks over a small disc of ground, thinning toward the edge.

Parameters

stateProvider

BlockStateProvider

Returns

ConfiguredFeature

---

blockPosHashCode()

blockPosHashCode(position): number

Defined in: features/javaHashSet.ts:4

Java's BlockPos.hashCode().

Parameters

position

BlockPos

Returns

number

---

blockPredicateFilter()

blockPredicateFilter(predicate): PlacementModifier

Defined in: placement/modifiers.ts:161

Keeps the position when a block predicate holds there.

Parameters

predicate

BlockPredicate

Returns

PlacementModifier

---

blockState()

blockState(name, properties?): BlockState

Defined in: world/BlockState.ts:62

Builds a block state, sharing one frozen object for the common property-free case.

Parameters

name

string

properties?

Readonly<Record<string, string>>

Returns

BlockState

---

blockStateKey()

blockStateKey(state): string

Defined in: world/BlockState.ts:81

Returns the canonical text form, minecraft:oak_log[axis=y], with properties in sorted order.

Two states are the same state when their keys are equal, which is what the feature code compares instead of walking property maps.

Parameters

state

BlockState

Returns

string

---

blueIce()

blueIce(): ConfiguredFeature

Defined in: features/simple.ts:177

Grows a patch of blue ice underwater beside packed ice.

Returns

ConfiguredFeature

---

bonusChest()

bonusChest(): ConfiguredFeature

Defined in: features/structural.ts:569

The bonus chest, Java's bonus_chest.

Returns

ConfiguredFeature

---

chorusPlant()

chorusPlant(): ConfiguredFeature

Defined in: features/structural.ts:873

A chorus plant, Java's chorus_plant.

Java delegates to ChorusFlowerBlock.generatePlant, which is block behavior rather than world generation. This places the flower and reports success; the growth pass belongs to the server's block layer, which is recorded in the README.

Returns

ConfiguredFeature

---

clampedInt()

clampedInt(source, min, max): IntProvider

Defined in: providers/valueProviders.ts:111

Clamps another provider's draw into [min, max]. Costs whatever the source costs.

Parameters

source

IntProvider

min

number

max

number

Returns

IntProvider

---

clampedNormalFloat()

clampedNormalFloat(mean, deviation, min, max): FloatProvider

Defined in: providers/valueProviders.ts:252

A normal distribution truncated into [min, max].

Parameters

mean

number

deviation

number

min

number

max

number

Returns

FloatProvider

---

clampedNormalInt()

clampedNormalInt(mean, deviation, min, max): IntProvider

Defined in: providers/valueProviders.ts:119

A normal distribution truncated into [min, max]. Costs the gaussian's draws.

Parameters

mean

number

deviation

number

min

number

max

number

Returns

IntProvider

---

constantFloat()

constantFloat(value): FloatProvider

Defined in: providers/valueProviders.ts:222

A constant. Costs no draws.

Parameters

value

number

Returns

FloatProvider

---

constantHeight()

constantHeight(value): HeightProvider

Defined in: providers/heightProvider.ts:85

A fixed anchor. Costs no draws.

Parameters

value

VerticalAnchor

Returns

HeightProvider

---

constantInt()

constantInt(value): IntProvider

Defined in: providers/valueProviders.ts:41

A constant. Costs no draws.

Parameters

value

number

Returns

IntProvider

---

copyPropertiesProvider()

copyPropertiesProvider(source): BlockStateProvider

Defined in: providers/blockStateProvider.ts:201

Draws a source state, then overwrites its properties with the ones the world block declares.

Parameters

source

BlockStateProvider

Returns

BlockStateProvider

---

coralClaw()

coralClaw(block): ConfiguredFeature

Defined in: features/structural.ts:925

A coral claw, Java's coral_claw.

Parameters

block

PlacedFeature

Returns

ConfiguredFeature

---

coralTree()

coralTree(block): ConfiguredFeature

Defined in: features/structural.ts:882

A coral tree, Java's coral_tree.

Parameters

block

PlacedFeature

Returns

ConfiguredFeature

---

countOnEveryLayer()

countOnEveryLayer(count): PlacementModifier

Defined in: placement/modifiers.ts:227

Places count positions on every exposed floor in the column, working downward.

Java marks this deprecated and only the nether's vegetation still uses it. It keeps raising the layer index until a pass finds nothing, so the number of draws depends on the terrain.

Parameters

count

IntProvider

Returns

PlacementModifier

---

countPlacement()

countPlacement(count): PlacementModifier

Defined in: placement/modifiers.ts:104

Repeats the origin a drawn number of times.

Parameters

count

IntProvider

Returns

PlacementModifier

---

createTestOracle()

createTestOracle(tables?): BlockOracle

Defined in: world/TestFeatureWorld.ts:34

Builds a BlockOracle from plain tables.

A test declares only the blocks it cares about; everything unnamed is a solid, unreplaceable, untagged block, which is what a feature placed into stone sees.

Parameters

tables?

TestOracleTables = {}

Returns

BlockOracle

---

cuboidPlacement()

cuboidPlacement(xzSize, ySize, includeEdges, includeInterior): PlacementModifier

Defined in: placement/modifiers.ts:286

Emits every position of a box anchored at the origin, optionally hollow or shell-free.

Parameters

xzSize

IntProvider

ySize

IntProvider

includeEdges

boolean

includeInterior

boolean

Returns

PlacementModifier

---

decorateChunk()

decorateChunk(scheduled, context, levelSeed, chunkX, chunkZ): DecorationResult

Defined in: placement/pipeline.ts:161

Runs a chunk's whole decoration pass.

This is the entry point a chunk generator calls. It derives the population seed once, then reseeds the stream before each feature from that seed, the feature's index and its step, so every feature is independent of how many draws the ones before it made. Running the same plan against the same seed and chunk twice produces the same blocks, and running a subset of the plan does not move the rest.

Parameters

scheduled

readonly ScheduledFeature[]

The plan, which orderDecoration puts in Java's order.

context

PlacementContext

levelSeed

bigint

The world seed.

chunkX

number

The chunk's x coordinate, not a block coordinate.

chunkZ

number

The chunk's z coordinate.

Returns

DecorationResult

---

decorationStepIndex()

decorationStepIndex(step): number

Defined in: placement/pipeline.ts:35

Returns a step's ordinal, which the feature seed derivation multiplies by 10000.

Parameters

step

"lakes" | "raw_generation" | "local_modifications" | "underground_structures" | "surface_structures" | "strongholds" | "underground_ores" | "underground_decoration" | "fluid_springs" | "vegetal_decoration" | "top_layer_modification"

Returns

number

---

deltaFeature()

deltaFeature(contents, rim, size, rimSize): ConfiguredFeature

Defined in: features/simple.ts:511

Pours a lava delta with an offset rim over the basalt deltas floor.

Parameters

contents

BlockState

rim

BlockState

size

IntProvider

rimSize

IntProvider

Returns

ConfiguredFeature

---

disk()

disk(stateProvider, target, radius, halfHeight): ConfiguredFeature

Defined in: features/simple.ts:555

Lays a flat disc of blocks wherever a target predicate holds, within a drawn radius.

Parameters

stateProvider

BlockStateProvider

target

BlockPredicate

radius

IntProvider

halfHeight

number

Returns

ConfiguredFeature

---

distanceSquared()

distanceSquared(a, b): number

Defined in: features/support.ts:131

The squared Euclidean distance between two positions.

Parameters

a

BlockPos

b

BlockPos

Returns

number

---

dualNoiseProvider()

dualNoiseProvider(slowNoise, slowScale, varietyMin, varietyMax, noise, scale, states): BlockStateProvider

Defined in: providers/blockStateProvider.ts:94

Picks a varying subset of the states with a slow noise, then indexes that subset with the fast one. Costs no draws.

Java samples the slow noise once per candidate at a position shifted by a large constant, which is why the subset is stable across a region rather than per block.

Parameters

slowNoise

Noise

slowScale

number

varietyMin

number

varietyMax

number

noise

Noise

scale

number

states

readonly BlockState[]

Returns

BlockStateProvider

---

endGateway()

endGateway(exit, exact): ConfiguredFeature

Defined in: features/structural.ts:1015

An end gateway, Java's end_gateway.

Parameters

exit

BlockPos | undefined

exact

boolean

Returns

ConfiguredFeature

---

endIsland()

endIsland(): ConfiguredFeature

Defined in: features/structural.ts:970

A floating end island, Java's end_island.

Returns

ConfiguredFeature

---

endPlatform()

endPlatform(): ConfiguredFeature

Defined in: features/simple.ts:256

Builds the five by five obsidian platform an arrival in the end lands on.

Returns

ConfiguredFeature

---

endPodium()

endPodium(active): ConfiguredFeature

Defined in: features/structural.ts:986

The exit portal's bedrock podium, Java's end_podium.

Parameters

active

boolean

Returns

ConfiguredFeature

---

endSpike()

endSpike(spikes, crystalInvulnerable, crystalBeamTarget): ConfiguredFeature

Defined in: features/structural.ts:1049

The obsidian pillars of the end, Java's end_spike.

An empty spikes list means "derive the ten pillars from the world seed", which is what the vanilla configured feature ships; only the respawn animation passes explicit spikes.

Parameters

spikes

readonly EndSpike[]

crystalInvulnerable

boolean

crystalBeamTarget

BlockPos | undefined

Returns

ConfiguredFeature

---

endSpikesForSeed()

endSpikesForSeed(seed): readonly EndSpike[]

Defined in: features/endSpikes.ts:31

Derives the ten spike pillars from the world seed, Java's EndSpikeFeature.getSpikesForLevel and SpikeCacheLoader.load.

Java reduces the seed to a 16-bit cache key, new LegacyRandom(seed).nextLong() & 65535, then shuffles the indices 0 through 9 with a second generator seeded by that key. Pillar i sits at floor(42 * cos(2 * (-PI + 0.3141592653589793 * i))) by the matching sine, and its shuffled index n shapes it: radius 2 + n / 3, height 76 + 3 * n, an iron-bar cage when n is 1 or 2.

Parameters

seed

bigint

Returns

readonly EndSpike[]

The ten pillars in Java's order, counterclockwise from (42, 0).

---

environmentScan()

environmentScan(directionOfSearch, targetCondition, allowedSearchCondition, maxSteps): PlacementModifier

Defined in: placement/modifiers.ts:258

Walks up or down looking for a position that satisfies a predicate.

The scan stops at the first target hit, at the world edge, or when the search condition stops holding, and it tests the target once more after the final step, which is how a scan of max_steps can land one block past its last move.

Parameters

directionOfSearch

VerticalDirection

targetCondition

BlockPredicate

allowedSearchCondition

BlockPredicate

maxSteps

number

Returns

PlacementModifier

---

fail()

fail(path, message): never

Defined in: json.ts:11

Raises a parse error naming the JSON path that failed.

Parameters

path

string

message

string

Returns

never

---

fallenTree()

fallenTree(trunkProvider, logLength, stumpDecorators, logDecorators): ConfiguredFeature

Defined in: features/structural.ts:1344

A fallen log with its stump, Java's fallen_tree.

Parameters

trunkProvider

BlockStateProvider

logLength

IntProvider

stumpDecorators

readonly TreeDecorator[]

logDecorators

readonly TreeDecorator[]

Returns

ConfiguredFeature

---

feature()

feature(type, place, children?): ConfiguredFeature

Defined in: features/Feature.ts:92

Builds a ConfiguredFeature from a placement function.

Parameters

type

"sequence" | "bamboo" | "block_blob" | "block_column" | "block_pile" | "blue_ice" | "bonus_chest" | "chorus_plant" | "coral_claw" | "coral_tree" | "delta_feature" | "disk" | "end_gateway" | "end_island" | "end_platform" | "end_podium" | "end_spike" | "fallen_tree" | "fill_layer" | "fossil" | "freeze_top_layer" | "geode" | "huge_brown_mushroom" | "huge_fungus" | "huge_red_mushroom" | "iceberg" | "lake" | "large_dripstone" | "monster_room" | "multiface_growth" | "netherrack_replace_blobs" | "no_op" | "ore" | "overlay" | "projected_random_patchy_square" | "random_boolean_selector" | "random_neighbor_spread" | "random_selector" | "replace_single_block" | "root_system" | "scattered_ore" | "sculk_patch" | "simple_block" | "simple_random_selector" | "single_block_pillar" | "speleothem" | "speleothem_cluster" | "spike" | "spring_feature" | "stepped_column_cluster" | "template" | "tree" | "underwater_magma" | "vegetation_patch" | "vines" | "void_start_platform" | "waterlogged_vegetation_patch" | "weighted_random_selector"

place

(world, random, origin) => boolean

children?

readonly ConfiguredFeature[]

Returns

ConfiguredFeature

---

fillLayer()

fillLayer(height, state): ConfiguredFeature

Defined in: features/simple.ts:162

Fills one y level of the chunk with a state, wherever that level is air.

Parameters

height

number

state

BlockState

Returns

ConfiguredFeature

---

fixedPlacement()

fixedPlacement(positions): PlacementModifier

Defined in: placement/modifiers.ts:324

Emits the listed absolute positions that fall in the origin's chunk.

Parameters

positions

readonly BlockPos[]

Returns

PlacementModifier

---

fossil()

fossil(fossilStructures, overlayStructures, fossilProcessors, overlayProcessors, maxEmptyCornersAllowed): ConfiguredFeature

Defined in: features/structural.ts:628

Buries a fossil, Java's fossil.

Parameters

fossilStructures

readonly string[]

overlayStructures

readonly string[]

fossilProcessors

string

overlayProcessors

string

maxEmptyCornersAllowed

number

Returns

ConfiguredFeature

---

freezeTopLayer()

freezeTopLayer(): ConfiguredFeature

Defined in: features/simple.ts:391

Freezes exposed water and lays a snow layer across the chunk.

Java decides both from the biome's temperature at the position and from the block light there. Temperature comes through import('../world/FeatureWorld').FeatureWorld.isColdEnoughToSnow and light is taken as dark, which is what a chunk being generated has everywhere but under a light-emitting block.

Returns

ConfiguredFeature

---

geode()

geode(config): ConfiguredFeature

Defined in: features/structural.ts:107

An amethyst geode, Java's geode.

It is a metaball field: several points are scattered inside the origin's neighborhood, and every block in the generation box sums the inverse square roots of its distances to them. Four thresholds on that sum cut the sum into the four shells, and a second field of three points cuts the crack through them.

Parameters

config

GeodeConfig

Returns

ConfiguredFeature

---

heightRange()

heightRange(height): PlacementModifier

Defined in: placement/modifiers.ts:134

Replaces the position's y with a draw from a height provider.

Parameters

height

HeightProvider

Returns

PlacementModifier

---

heightmapPlacement()

heightmapPlacement(heightmap): PlacementModifier

Defined in: placement/modifiers.ts:142

Moves the position to the top of a heightmap column, dropping it when the column is empty.

Parameters

heightmap

HeightmapType

Returns

PlacementModifier

---

hugeBrownMushroom()

hugeBrownMushroom(config): ConfiguredFeature

Defined in: features/structural.ts:1202

The brown mushroom's flat cap, Java's huge_brown_mushroom.

Parameters

config

HugeMushroomConfig

Returns

ConfiguredFeature

---

hugeFungus()

hugeFungus(validBaseState, stemState, hatState, decorState, replaceableBlocks, planted): ConfiguredFeature

Defined in: features/structural.ts:1234

A huge nether fungus, Java's huge_fungus.

Parameters

validBaseState

BlockState

stemState

BlockState

hatState

BlockState

decorState

BlockState

replaceableBlocks

BlockPredicate

planted

boolean

Returns

ConfiguredFeature

---

hugeRedMushroom()

hugeRedMushroom(config): ConfiguredFeature

Defined in: features/structural.ts:1170

The red mushroom's domed cap, Java's huge_red_mushroom.

Parameters

config

HugeMushroomConfig

Returns

ConfiguredFeature

---

iceberg()

iceberg(state): ConfiguredFeature

Defined in: features/structural.ts:323

An iceberg, Java's iceberg.

Parameters

state

BlockState

Returns

ConfiguredFeature

---

inBlockSet()

inBlockSet(blocks, state, set): boolean

Defined in: features/support.ts:123

Answers whether a state is in a parsed HolderSet<Block>.

Parameters

blocks

BlockOracle

state

BlockState

set

BlockSet

Returns

boolean

---

inSquare()

inSquare(): PlacementModifier

Defined in: placement/modifiers.ts:116

Scatters the position uniformly across the chunk's 16 by 16 footprint, keeping its y.

Returns

PlacementModifier

---

isBlock()

isBlock(state, name): boolean

Defined in: world/BlockState.ts:88

Answers whether two states name the same block, ignoring their properties.

Parameters

state

BlockState

name

string

Returns

boolean

---

isEmptyBlock()

isEmptyBlock(world, position): boolean

Defined in: features/support.ts:22

Answers Java's LevelAccessor.isEmptyBlock.

Parameters

world

FeatureWorld

position

BlockPos

Returns

boolean

---

isOutsideBuildHeight()

isOutsideBuildHeight(world, y): boolean

Defined in: world/FeatureWorld.ts:220

Answers whether y is outside the dimension's generated range.

Parameters

world

FeatureWorld

y

number

Returns

boolean

---

lake()

lake(fluid, barrier, canPlaceFeature, canReplaceWithAirOrFluid, canReplaceWithBarrier): ConfiguredFeature

Defined in: features/structural.ts:221

A lake, Java's lake.

The shape is drawn into a 16 by 8 by 16 boolean grid by four to seven overlapping ellipsoids, checked against the world, and then written twice: fluid below y offset 4 and cave air above it, then a barrier shell around whatever that touched.

Parameters

fluid

BlockStateProvider

barrier

BlockStateProvider

canPlaceFeature

BlockPredicate

canReplaceWithAirOrFluid

BlockPredicate

canReplaceWithBarrier

BlockPredicate

Returns

ConfiguredFeature

---

largeDripstone()

largeDripstone(config): ConfiguredFeature

Defined in: features/caves.ts:432

The cave-spanning dripstone cone pair, Java's large_dripstone.

Parameters

config

LargeDripstoneConfig

Returns

ConfiguredFeature

---

manhattan()

manhattan(a, b): number

Defined in: features/support.ts:127

The Manhattan distance between two positions.

Parameters

a

BlockPos

b

BlockPos

Returns

number

---

monsterRoom()

monsterRoom(): ConfiguredFeature

Defined in: features/structural.ts:488

The dungeon, Java's monster_room.

Returns

ConfiguredFeature

---

mthCos()

mthCos(value): number

Defined in: features/support.ts:120

Java's Mth.cos, the same table a quarter turn along.

Parameters

value

number

Returns

number

---

mthSin()

mthSin(value): number

Defined in: features/support.ts:117

Java's Mth.sin, which reads a 65536-entry float table rather than calling Math.sin.

The two differ by up to about 5e-5, which is enough to move an ore vein's sphere radii across a block boundary, so worldgen code that calls Mth.sin has to call this and code that calls java.lang.Math.sin has to call Math.sin.

Parameters

value

number

Returns

number

---

multifaceGrowth()

multifaceGrowth(placeBlock, searchRange, canPlaceOnFloor, canPlaceOnCeiling, canPlaceOnWall, canBePlacedOn): ConfiguredFeature

Defined in: features/simple.ts:656

Grows a face-attached block such as glow lichen or sculk vein onto a nearby surface.

Java then rolls chance_of_spreading and, when it passes, asks the block's own spreader to continue from the placed face. The spreader is block behavior rather than world generation, so this places the first face and stops; the README records the spread pass as the caller's job. The roll is still drawn, because it costs one float whichever way it lands, and the chance itself therefore does not reach this function.

Parameters

placeBlock

string

searchRange

number

canPlaceOnFloor

boolean

canPlaceOnCeiling

boolean

canPlaceOnWall

boolean

canBePlacedOn

BlockSet

Returns

ConfiguredFeature

---

netherrackReplaceBlobs()

netherrackReplaceBlobs(target, replacement, radius): ConfiguredFeature

Defined in: features/simple.ts:469

Finds the nearest target block below and replaces a Manhattan blob of it.

Parameters

target

BlockState

replacement

BlockState

radius

IntProvider

Returns

ConfiguredFeature

---

nextDoubleBetween()

nextDoubleBetween(random, min, max): number

Defined in: placement/WorldgenRandom.ts:240

Returns a double in [min, max), as Java's Mth.nextDouble does.

Parameters

random

RandomSource

min

number

max

number

Returns

number

---

nextFloatBetween()

nextFloatBetween(random, min, max): number

Defined in: placement/WorldgenRandom.ts:236

Returns a float in [min, max) collapsed to min when inverted, as Mth.nextFloat does.

Parameters

random

RandomSource

min

number

max

number

Returns

number

---

nextIntBetween()

nextIntBetween(random, min, max): number

Defined in: placement/WorldgenRandom.ts:228

Returns an integer in [min, max], collapsing an inverted range to min, as Mth.nextInt does.

Parameters

random

RandomSource

min

number

max

number

Returns

number

---

noOp()

noOp(): ConfiguredFeature

Defined in: features/simple.ts:52

Builds the no_op feature, which Java reports as a successful placement that wrote nothing.

Returns

ConfiguredFeature

---

noiseBasedCount()

noiseBasedCount(noiseToCountRatio, noiseFactor, noiseOffset): PlacementModifier

Defined in: placement/modifiers.ts:190

Repeats the origin a number of times scaled from the shared biome-info noise.

Parameters

noiseToCountRatio

number

noiseFactor

number

noiseOffset

number

Returns

PlacementModifier

---

noiseProvider()

noiseProvider(noise, scale, states): BlockStateProvider

Defined in: providers/blockStateProvider.ts:72

Indexes a state list by a normal noise sampled at the position. Costs no draws.

It is positional rather than random, which is what makes a noise-picked flower field look like patches instead of static.

Parameters

noise

Noise

scale

number

states

readonly BlockState[]

Returns

BlockStateProvider

---

noiseThresholdCount()

noiseThresholdCount(noiseLevel, belowNoise, aboveNoise): PlacementModifier

Defined in: placement/modifiers.ts:184

Repeats the origin a number of times read from the shared biome-info noise.

Parameters

noiseLevel

number

belowNoise

number

aboveNoise

number

Returns

PlacementModifier

---

noiseThresholdProvider()

noiseThresholdProvider(noise, scale, threshold, highChance, defaultState, lowStates, highStates): BlockStateProvider

Defined in: providers/blockStateProvider.ts:115

Splits on a noise threshold, then draws uniformly from one side. Costs up to two draws.

Parameters

noise

Noise

scale

number

threshold

number

highChance

number

defaultState

BlockState

lowStates

readonly BlockState[]

highStates

readonly BlockState[]

Returns

BlockStateProvider

---

normal()

normal(random, mean, deviation): number

Defined in: placement/WorldgenRandom.ts:244

Returns a normally distributed float, as Java's Mth.normal does.

Parameters

random

RandomSource

mean

number

deviation

number

Returns

number

---

normalizeIdentifier()

normalizeIdentifier(value, path): string

Defined in: registry.ts:11

Expands a registry reference to its namespace:path form.

Mojang's data leaves minecraft off in some places and spells it out in others, so every lookup goes through here first.

Parameters

value

unknown

path

string

Returns

string

---

offset()

offset(origin, dx, dy, dz): BlockPos

Defined in: world/FeatureWorld.ts:14

Returns origin moved by a delta.

Parameters

origin

BlockPos

dx

number

dy

number

dz

number

Returns

BlockPos

---

offsetPlacement()

offsetPlacement(x, y, z): PlacementModifier

Defined in: placement/modifiers.ts:126

Moves the position by a drawn offset on each axis, in x, y, z draw order.

Parameters

x

IntProvider

y

IntProvider

z

IntProvider

Returns

PlacementModifier

---

oppositeDirection()

oppositeDirection<D>(direction): object[D]

Defined in: world/BlockState.ts:57

Returns the direction facing the other way.

Type Parameters

D

D extends Direction

Parameters

direction

D

Returns

object[D]

---

orderDecoration()

orderDecoration(scheduled): ScheduledFeature[]

Defined in: placement/pipeline.ts:116

Sorts a decoration plan into Java's execution order: step first, then index within the step.

Parameters

scheduled

readonly ScheduledFeature[]

Returns

ScheduledFeature[]

---

ore()

ore(targets, size, discardChanceOnAirExposure): ConfiguredFeature

Defined in: features/ore.ts:56

The vein-shaped ore, Java's OreFeature.

It draws a line through the origin at a random horizontal angle, hangs size spheres along it with radii that swell toward the middle, discards spheres swallowed by their neighbors, and fills the union. The distinctive part is that the discard pass runs before any block is written, so the vein's shape is decided entirely by size and four draws.

Parameters

targets

readonly BlockReplacement[]

size

number

discardChanceOnAirExposure

number

Returns

ConfiguredFeature

---

outsideBuildHeight()

outsideBuildHeight(world, y): boolean

Defined in: features/support.ts:54

Answers whether a y is outside the generated range.

Parameters

world

FeatureWorld

y

number

Returns

boolean

---

overlay()

overlay(features): ConfiguredFeature

Defined in: features/simple.ts:108

Runs every placed feature at the same origin, reporting whether any placed.

Parameters

features

readonly PlacedFeature[]

Returns

ConfiguredFeature

---

parseBlockPredicate()

parseBlockPredicate(source, path): BlockPredicate

Defined in: providers/blockPredicate.ts:80

Reads a block_predicate_type document.

matching_blocks, matching_fluids and matching_biomes accept a #tag reference as well as a list, which this resolves through FeatureWorld.blocks rather than at parse time, so a predicate stays usable when tag data changes.

Parameters

source

unknown

path

string

Returns

BlockPredicate

---

parseBlockReplacement()

parseBlockReplacement(source, path): BlockReplacement

Defined in: features/ruleTest.ts:107

Reads a {"target": ..., "state": ...} replacement.

Parameters

source

unknown

path

string

Returns

BlockReplacement

---

parseBlockReplacements()

parseBlockReplacements(source, path): BlockReplacement[]

Defined in: features/ruleTest.ts:116

Reads the list of replacements an ore or a replace_single_block carries.

Parameters

source

unknown

path

string

Returns

BlockReplacement[]

---

parseBlockSet()

parseBlockSet(source, path): BlockSet

Defined in: registry.ts:40

Reads a HolderSet<Block>: a tag reference, one identifier, or an inline list of them.

Parameters

source

unknown

path

string

Returns

BlockSet

---

parseBlockState()

parseBlockState(source, path): BlockState

Defined in: providers/blockStateProvider.ts:219

Reads a block state.

26.3 accepts a bare identifier wherever a state is expected, which is how most of the feature data spells a block with no interesting properties.

Parameters

source

unknown

path

string

Returns

BlockState

---

parseBlockStateProvider()

parseBlockStateProvider(source, path, resolve?): BlockStateProvider

Defined in: providers/blockStateProvider.ts:254

Reads a worldgen/block_state_provider_type document.

Three spellings are accepted, because 26.3 accepts all three: a bare identifier is a reference into the block_state_provider registry, which vanilla uses for the eight shared providers such as soil_beneath_tree; a bare {"id": ...} object or a bare identifier string in a state position is a simple provider; and an object with a type is a typed provider.

Parameters

source

unknown

path

string

resolve?

BlockStateProviderResolver

Returns

BlockStateProvider

---

parseCaveFeature()

parseCaveFeature(type, raw, path, parsers): ConfiguredFeature | undefined

Defined in: features/caves.ts:801

Reads the cave feature types.

Parameters

type

string

raw

Record<string, unknown>

path

string

parsers

FeatureParsers

Returns

ConfiguredFeature | undefined

---

parseDirection()

parseDirection(value, path): Direction

Defined in: providers/blockPredicate.ts:218

Reads a Direction.

Parameters

value

unknown

path

string

Returns

Direction

---

parseFloatProvider()

parseFloatProvider(source, path): FloatProvider

Defined in: providers/valueProviders.ts:260

Reads a FloatProvider. A bare number is a constant.

Parameters

source

unknown

path

string

Returns

FloatProvider

---

parseHeightProvider()

parseHeightProvider(source, path): HeightProvider

Defined in: providers/heightProvider.ts:152

Reads a HeightProvider. A bare anchor object is a constant.

Parameters

source

unknown

path

string

Returns

HeightProvider

---

parseIntProvider()

parseIntProvider(source, path): IntProvider

Defined in: providers/valueProviders.ts:148

Reads an IntProvider.

A bare number is a constant, which is how most of the data spells a fixed count.

Parameters

source

unknown

path

string

Returns

IntProvider

---

parseOreFeature()

parseOreFeature(type, raw, path): ConfiguredFeature | undefined

Defined in: features/ore.ts:205

Reads the two ore feature types, which share a configuration shape.

Parameters

type

string

raw

Record<string, unknown>

path

string

Returns

ConfiguredFeature | undefined

---

parsePlacedFeature()

parsePlacedFeature(source, path, resolveFeature): PlacedFeature

Defined in: placement/pipeline.ts:123

Reads a worldgen/placed_feature document, resolving its feature reference.

Parameters

source

unknown

path

string

resolveFeature

(value, path) => ConfiguredFeature

Returns

PlacedFeature

---

parsePlacementModifier()

parsePlacementModifier(source, path): PlacementModifier

Defined in: placement/modifiers.ts:347

Reads one worldgen/placement_modifier_type document.

Parameters

source

unknown

path

string

Returns

PlacementModifier

---

parseRuleTest()

parseRuleTest(source, path): RuleTest

Defined in: features/ruleTest.ts:34

Reads a rule_test document. The dispatch key is predicate_type, not type.

Parameters

source

unknown

path

string

Returns

RuleTest

---

parseSimpleFeature()

parseSimpleFeature(type, raw, path, parsers): ConfiguredFeature | undefined

Defined in: features/simple.ts:811

Reads the simple feature types, given the parsers for the nested documents they carry.

Parameters

type

string

raw

Record<string, unknown>

path

string

parsers

FeatureParsers

Returns

ConfiguredFeature | undefined

---

parseStructuralFeature()

parseStructuralFeature(type, raw, path, parsers): ConfiguredFeature | undefined

Defined in: features/structural.ts:1434

Reads the structural feature types.

Parameters

type

string

raw

Record<string, unknown>

path

string

parsers

FeatureParsers

Returns

ConfiguredFeature | undefined

---

parseTreeConfig()

parseTreeConfig(raw, path, parsers): TreeConfig

Defined in: features/tree/parse.ts:300

Reads a minecraft:tree configuration.

Parameters

raw

Record<string, unknown>

path

string

parsers

FeatureParsers

Returns

TreeConfig

---

parseTreeFeature()

parseTreeFeature(type, raw, path, parsers): ConfiguredFeature | undefined

Defined in: features/tree.ts:127

Reads the tree feature type.

Parameters

type

string

raw

Record<string, unknown>

path

string

parsers

FeatureParsers

Returns

ConfiguredFeature | undefined

---

parseVerticalAnchor()

parseVerticalAnchor(source, path): VerticalAnchor

Defined in: providers/heightProvider.ts:51

Reads a VerticalAnchor, which is an object with exactly one of the four keys.

Parameters

source

unknown

path

string

Returns

VerticalAnchor

---

parseWeightedList()

parseWeightedList<T>(source, path, parseEntry): Weighted<T>[]

Defined in: providers/valueProviders.ts:296

Reads a Java WeightedList, which is a list of {data, weight} entries.

The declared order is kept, because randomWeighted walks it and a reordering would change which entry a given draw selects.

Type Parameters

T

T

Parameters

source

unknown

path

string

parseEntry

(value, path) => T

Returns

Weighted<T>[]

---

placeFeature()

placeFeature(placed, context, random, origin): boolean

Defined in: placement/pipeline.ts:60

Runs a placed feature's modifier chain and places the feature at every position it yields.

The traversal is Java's, and it is depth first rather than stage by stage: the first position a modifier emits runs all the way to the end of the chain before the second one starts. That decides the order of the random draws, so a breadth-first version with the same modifiers produces a different world from the same seed.

Parameters

placed

PlacedFeature

context

PlacementContext

random

RandomSource

origin

BlockPos

Returns

boolean

Whether any placement of the feature reported success.

---

pos()

pos(x, y, z): BlockPos

Defined in: world/FeatureWorld.ts:11

Builds a position.

Parameters

x

number

y

number

z

number

Returns

BlockPos

---

posKey()

posKey(position): string

Defined in: world/FeatureWorld.ts:24

The canonical text key for a position, which the test world uses to index its store.

Parameters

position

BlockPos

Returns

string

---

predicateTypeNameOf()

predicateTypeNameOf(value, path): string

Defined in: registry.ts:25

Strips the minecraft: prefix, reading the key the predicate registries dispatch on.

Parameters

value

unknown

path

string

Returns

string

---

projectedRandomPatchySquare()

projectedRandomPatchySquare(block, projectThrough, size, maxProjectionHeight): ConfiguredFeature

Defined in: features/simple.ts:781

Scatters blocks over a square, thinning toward the corners, dropping each one onto the surface below it.

26.3 added this and removed random_patch. The corner thinning is the whole difference: a position's chance of being used falls with the product of its two offsets, so the patch comes out round rather than square.

Parameters

block

BlockStateProvider

projectThrough

BlockPredicate

size

IntProvider

maxProjectionHeight

number

Returns

ConfiguredFeature

---

randomBetween()

randomBetween(random, min, max): number

Defined in: placement/WorldgenRandom.ts:232

Returns a float in [min, max), as Java's Mth.randomBetween does.

Parameters

random

RandomSource

min

number

max

number

Returns

number

---

randomBetweenInclusive()

randomBetweenInclusive(random, min, max): number

Defined in: placement/WorldgenRandom.ts:224

Returns an integer in [min, max], as Java's Mth.randomBetweenInclusive does.

Parameters

random

RandomSource

min

number

max

number

Returns

number

---

randomBlockProvider()

randomBlockProvider(names, tag?): BlockStateProvider

Defined in: providers/blockStateProvider.ts:193

Draws one block uniformly from a set and uses its default state.

The vanilla uses name a tag (#minecraft:corals), so this needs the oracle to enumerate it. When the oracle cannot, the provider yields nothing and the caller keeps the existing block, which is Java's behavior for an empty holder set.

Parameters

names

readonly string[]

tag?

string

Returns

BlockStateProvider

---

randomBooleanSelector()

randomBooleanSelector(whenTrue, whenFalse): ConfiguredFeature

Defined in: features/simple.ts:66

Runs one of two placed features on a coin flip.

Parameters

whenTrue

PlacedFeature

whenFalse

PlacedFeature

Returns

ConfiguredFeature

---

randomChance()

randomChance(chance): PlacementModifier

Defined in: placement/modifiers.ts:112

Keeps the position with the given probability.

Parameters

chance

number

Returns

PlacementModifier

---

randomElement()

randomElement<T>(items, random): T

Defined in: placement/WorldgenRandom.ts:248

Picks one element uniformly, as Java's Util.getRandom(List, RandomSource) does.

Type Parameters

T

T

Parameters

items

readonly T[]

random

RandomSource

Returns

T

---

randomNeighborSpread()

randomNeighborSpread(block, acceptedNeighbors, canReplace, attempts, xzOffset, yOffset): ConfiguredFeature

Defined in: features/simple.ts:353

Places a block at the origin and scatters more wherever exactly one accepted neighbor sits.

Parameters

block

BlockStateProvider

acceptedNeighbors

BlockSet

canReplace

BlockPredicate

attempts

IntProvider

xzOffset

IntProvider

yOffset

IntProvider

Returns

ConfiguredFeature

---

randomSelector()

randomSelector(features, fallback): ConfiguredFeature

Defined in: features/simple.ts:90

Walks a list of chance-weighted features, taking the first whose roll succeeds.

Java marks this deprecated in favor of weighted_random_selector, but 21 vanilla features still use it, and the draw pattern differs: this rolls once per entry until one passes, so the number of draws depends on where the winner sits.

Parameters

features

readonly object[]

fallback

PlacedFeature

Returns

ConfiguredFeature

---

randomWeighted()

randomWeighted<T>(entries, random): T

Defined in: placement/WorldgenRandom.ts:266

Draws one entry by weight, as Java's WeightedList.getRandomOrThrow does.

Java draws nextInt(totalWeight) and walks the list subtracting weights, so the draw count and the tie-breaking order both depend on the declared order of the entries.

Type Parameters

T

T

Parameters

entries

readonly Weighted<T>[]

random

RandomSource

Returns

T

---

randomizedIntProvider()

randomizedIntProvider(source, property, values): BlockStateProvider

Defined in: providers/blockStateProvider.ts:137

Draws a source state, then randomizes one integer property on it.

Java looks the property up in the block's real state definition. This package has no block registry, so it sets the property when the source state declares it and leaves the state alone when it does not, which is the same answer for every provider in the vanilla data because each one spells the property out in its source state.

Parameters

source

BlockStateProvider

property

string

values

IntProvider

Returns

BlockStateProvider

---

randomlySelected()

randomlySelected(placements): PlacementModifier

Defined in: placement/modifiers.ts:316

Runs one of several modifiers, drawn uniformly.

Parameters

placements

readonly PlacementModifier[]

Returns

PlacementModifier

---

rarityFilter()

rarityFilter(chance): PlacementModifier

Defined in: placement/modifiers.ts:108

Keeps the position with probability 1 / chance. Costs one draw whether it passes or not.

Parameters

chance

number

Returns

PlacementModifier

---

readStateObject()

readStateObject(source, path): Record<string, unknown>

Defined in: features/caves.ts:924

Shared with the structural features, which also read a block state object out of a field.

Parameters

source

unknown

path

string

Returns

Record<string, unknown>

---

relative()

relative(position, direction, distance?): BlockPos

Defined in: features/support.ts:10

Returns the position one step in a direction.

Parameters

position

BlockPos

direction

Direction

distance?

number = 1

Returns

BlockPos

---

replaceSingleBlock()

replaceSingleBlock(replacements): ConfiguredFeature

Defined in: features/simple.ts:150

Replaces the block at the origin with the first replacement whose rule test matches.

Parameters

replacements

readonly BlockReplacement[]

Returns

ConfiguredFeature

---

resolveAnchor()

resolveAnchor(anchor, context): number

Defined in: providers/heightProvider.ts:37

Resolves an anchor to a y in the given dimension.

Parameters

anchor

VerticalAnchor

context

VerticalContext

Returns

number

---

rootSystem()

rootSystem(config): ConfiguredFeature

Defined in: features/structural.ts:689

The azalea tree's rooted dirt column, Java's root_system.

Parameters

config

RootSystemConfig

Returns

ConfiguredFeature

---

rotatedProvider()

rotatedProvider(source, direction?): BlockStateProvider

Defined in: providers/blockStateProvider.ts:154

Draws a source state and turns it to face a direction, randomly when none is given.

trySetValue in Java sets a property only when the block has it. Here that is the same test against the state's declared properties.

Parameters

source

BlockStateProvider

direction?

Direction

Returns

BlockStateProvider

---

ruleBasedProvider()

ruleBasedProvider(rules, fallback?): BlockStateProvider

Defined in: providers/blockStateProvider.ts:173

Takes the first rule whose predicate holds, falling back when none does.

Parameters

rules

readonly object[]

fallback?

BlockStateProvider

Returns

BlockStateProvider

---

safeSetBlock()

safeSetBlock(world, position, state, canReplace): boolean

Defined in: features/support.ts:26

Writes a state only when a test on the block already there passes, Java's safeSetBlock.

Parameters

world

FeatureWorld

position

BlockPos

state

BlockState

canReplace

(existing) => boolean

Returns

boolean

---

sameState()

sameState(a, b): boolean

Defined in: world/BlockState.ts:91

Answers whether two states are identical, properties included.

Parameters

a

BlockState

b

BlockState

Returns

boolean

---

scanColumn()

scanColumn(world, origin, searchRange, inside, validEdge): ScannedColumn | undefined

Defined in: features/caves.ts:61

Java's Column.scan.

It walks up to searchRange - 1 steps in each direction while inside holds, and reports the stopping position only when validEdge holds there. Both ends are the edge block, not the last inside block, which is why a caller adds or subtracts one before placing.

Parameters

world

FeatureWorld

origin

BlockPos

searchRange

number

inside

(state, world) => boolean

validEdge

(state, world) => boolean

Returns

ScannedColumn | undefined

---

scatteredOre()

scatteredOre(targets, size, discardChanceOnAirExposure): ConfiguredFeature

Defined in: features/ore.ts:181

The loose ore, Java's ScatteredOreFeature.

It makes up to size independent attempts, each at a position drawn from a difference of two floats so the spread is triangular rather than uniform, and each capped at seven blocks from the origin. Copper in the dripstone caves is the only vanilla user.

Parameters

targets

readonly BlockReplacement[]

size

number

discardChanceOnAirExposure

number

Returns

ConfiguredFeature

---

sculkPatch()

sculkPatch(chargeCount, amountPerCharge, spreadAttempts, growthRounds, spreadRounds): ConfiguredFeature

Defined in: features/caves.ts:661

The sculk patch, Java's sculk_patch.

Java runs its SculkSpreader here, which is the same charge-and-cursor simulation the sculk catalyst uses at runtime and lives in the block layer rather than in world generation. This places the seed block and reports success, and the README records the spreader as the caller's job: a server that has sculk behavior already owns the algorithm.

Parameters

chargeCount

number

amountPerCharge

number

spreadAttempts

number

growthRounds

number

spreadRounds

number

Returns

ConfiguredFeature

---

sequence()

sequence(features): ConfiguredFeature

Defined in: features/simple.ts:120

Runs every placed feature in order and stops at the first failure.

Parameters

features

readonly PlacedFeature[]

Returns

ConfiguredFeature

---

shuffledCopy()

shuffledCopy<T>(items, random): T[]

Defined in: features/support.ts:40

Shuffles a copy of a list the way Java's Util.shuffle does.

The direction order several features draw out of this decides which face a growth attaches to, so the swap order matters as much as the result: Java walks from the end and swaps with a draw in [0, i).

Type Parameters

T

T

Parameters

items

readonly T[]

random

RandomSource

Returns

T[]

---

simpleBlock()

simpleBlock(toPlace, scheduleTick): ConfiguredFeature

Defined in: features/simple.ts:139

Places one block, if it would survive there.

Java has two special cases this cannot reproduce without a block registry: a double plant places both halves, and a mossy carpet spreads onto its neighbors. Both are recorded in the README as the places where a server's own block behavior has to finish the job.

Parameters

toPlace

BlockStateProvider

scheduleTick

boolean

Returns

ConfiguredFeature

---

simpleProvider()

simpleProvider(state): BlockStateProvider

Defined in: providers/blockStateProvider.ts:58

Always the same state.

Parameters

state

BlockState

Returns

BlockStateProvider

---

simpleRandomSelector()

simpleRandomSelector(features): ConfiguredFeature

Defined in: features/simple.ts:55

Runs one of several placed features, drawn uniformly. Costs one draw.

Parameters

features

readonly PlacedFeature[]

Returns

ConfiguredFeature

---

singleBlockPillar()

singleBlockPillar(block, canReplace, direction, chanceToContinue, capFeature?): ConfiguredFeature

Defined in: features/simple.ts:271

Stacks one block upward or downward while a predicate and a per-block chance both hold.

Parameters

block

BlockStateProvider

canReplace

BlockPredicate

direction

Direction

chanceToContinue

number

capFeature?

PlacedFeature

Returns

ConfiguredFeature

---

sortFeaturesPerStep()

sortFeaturesPerStep(biomeFeatures): readonly (readonly string[])[]

Defined in: placement/featureSorter.ts:36

Merges every biome's per-step feature order into one order per step.

Parameters

biomeFeatures

Iterable<readonly (readonly string[])[]>

One entry per biome, each a list indexed by decoration step of the placed feature identifiers that biome runs in that step, in the biome's own order.

Returns

readonly (readonly string[])[]

One list per step, deduplicated and ordered. A feature's position in its step's list is the index that seeds it, so two biomes that share a feature seed it identically. The result has as many steps as the longest input, which may be fewer than the eleven Java defines.

Throws

Error when two biomes order the same pair of features opposite ways, which leaves no order that satisfies both. Java fails the same way, with Feature order cycle found.

---

speleothem()

speleothem(baseBlock, pointedBlock, replaceableBlocks, chanceOfTallerGeneration, chanceOfDirectionalSpread, chanceOfSpreadRadius2, chanceOfSpreadRadius3): ConfiguredFeature

Defined in: features/caves.ts:161

One pointed dripstone with a small patch of base block under it, Java's speleothem.

26.3 renamed this from pointed_dripstone and made the two blocks configurable, which is what lets the nether's sulfur spikes reuse it.

Parameters

baseBlock

string

pointedBlock

string

replaceableBlocks

BlockSet

chanceOfTallerGeneration

number

chanceOfDirectionalSpread

number

chanceOfSpreadRadius2

number

chanceOfSpreadRadius3

number

Returns

ConfiguredFeature

---

speleothemCluster()

speleothemCluster(config): ConfiguredFeature

Defined in: features/caves.ts:228

A field of stalactites and stalagmites, Java's speleothem_cluster.

Parameters

config

SpeleothemClusterConfig

Returns

ConfiguredFeature

---

spike()

spike(state, canPlaceOn, canReplace): ConfiguredFeature

Defined in: features/structural.ts:814

The basalt pillar and its nether cousins, Java's spike.

Parameters

state

BlockState

canPlaceOn

BlockPredicate

canReplace

BlockPredicate

Returns

ConfiguredFeature

---

springFeature()

springFeature(fluid, requiresBlockBelow, rockCount, holeCount, validBlocks): ConfiguredFeature

Defined in: features/simple.ts:584

Opens a one-block fluid spring in a wall with exactly the declared rock and hole counts.

Parameters

fluid

BlockState

requiresBlockBelow

boolean

rockCount

number

holeCount

number

validBlocks

BlockSet

Returns

ConfiguredFeature

---

steppedColumnCluster()

steppedColumnCluster(config): ConfiguredFeature

Defined in: features/caves.ts:697

The nether's stepped columns, Java's stepped_column_cluster.

Parameters

config

SteppedColumnClusterConfig

Returns

ConfiguredFeature

---

surfaceRelativeThresholdFilter()

surfaceRelativeThresholdFilter(heightmap, minInclusive, maxInclusive): PlacementModifier

Defined in: placement/modifiers.ts:165

Keeps the position when its y sits within a window around a heightmap's surface.

Parameters

heightmap

HeightmapType

minInclusive

number

maxInclusive

number

Returns

PlacementModifier

---

surfaceWaterDepthFilter()

surfaceWaterDepthFilter(maxWaterDepth): PlacementModifier

Defined in: placement/modifiers.ts:176

Keeps the position when no more than maxWaterDepth of water covers the ocean floor.

Parameters

maxWaterDepth

number

Returns

PlacementModifier

---

templateFeature()

templateFeature(templates, processors?): ConfiguredFeature

Defined in: features/structural.ts:606

Places one template from a weighted list, Java's template.

Parameters

templates

readonly object[]

processors?

TemplateProcessors

Returns

ConfiguredFeature

---

translatingWorld()

translatingWorld<Target>(target, mapper, blocks): FeatureWorld

Defined in: world/FeatureWorld.ts:248

Wraps a world that stores non-Java states so features can write Java states into it.

This is the injection point the plan's section 5 asks for: the mapping table is applied once, at the seam, rather than inside every feature.

Type Parameters

Target

Target

Parameters

target

TargetWorld<Target>

mapper

BlockStateMapper<Target>

blocks

BlockOracle

Returns

FeatureWorld

---

trapezoidFloat()

trapezoidFloat(min, max, plateau): FloatProvider

Defined in: providers/valueProviders.ts:238

A trapezoidal float distribution. Costs two draws.

Parameters

min

number

max

number

plateau

number

Returns

FloatProvider

---

trapezoidHeight()

trapezoidHeight(min, max, plateau): HeightProvider

Defined in: providers/heightProvider.ts:131

A trapezoidal y distribution with a flat top plateau wide. Costs one or two draws.

Parameters

min

VerticalAnchor

max

VerticalAnchor

plateau

number

Returns

HeightProvider

---

trapezoidInt()

trapezoidInt(min, max, plateau): IntProvider

Defined in: providers/valueProviders.ts:88

A trapezoidal distribution over [min, max] with a flat top plateau wide.

The symmetric triangle case, which the offset modifier uses everywhere, takes a shortcut of two draws from the same bound rather than the general two-draw form.

Parameters

min

number

max

number

plateau

number

Returns

IntProvider

---

tree()

tree(config): ConfiguredFeature

Defined in: features/tree.ts:46

Builds a tree, Java's TreeFeature.

Forty-five of the 240 vanilla configured features are this one type. All of the variety lives in the four composable parts: a trunk placer that returns where foliage should attach, a foliage placer that fills those attachments, an optional root placer, and a list of decorators.

The order of the draws is the part worth stating. tree_height comes first, then foliage_height, then foliage_radius, then the root placer's trunk offset, then the whole trunk, then each attachment's foliage in the order the trunk placer returned them, then the decorators in their declared order. Moving any of those moves every block after it.

Parameters

config

TreeConfig

Returns

ConfiguredFeature

---

typeNameOf()

typeNameOf(value, path): string

Defined in: registry.ts:19

Strips the minecraft: prefix from a dispatch key so a switch can match the short form.

Parameters

value

unknown

path

string

Returns

string

---

underwaterMagma()

underwaterMagma(floorSearchRange, placementRadiusAroundFloor, placementProbabilityPerValidPosition): ConfiguredFeature

Defined in: features/simple.ts:300

Scatters magma blocks on an underwater floor, avoiding any that would be visible from the side.

Parameters

floorSearchRange

number

placementRadiusAroundFloor

number

placementProbabilityPerValidPosition

number

Returns

ConfiguredFeature

---

uniformFloat()

uniformFloat(min, max): FloatProvider

Defined in: providers/valueProviders.ts:230

A uniform float in [min, max). Costs one draw.

Parameters

min

number

max

number

Returns

FloatProvider

---

uniformHeight()

uniformHeight(min, max): HeightProvider

Defined in: providers/heightProvider.ts:96

A uniform y in [min, max]. Costs one draw.

Java collapses an inverted range to min with a warning rather than failing, because the range depends on the dimension and a datapack cannot always know it is valid. Reproduced here.

Parameters

min

VerticalAnchor

max

VerticalAnchor

Returns

HeightProvider

---

uniformInt()

uniformInt(min, max): IntProvider

Defined in: providers/valueProviders.ts:49

A uniform integer in [min, max]. Costs one draw.

Parameters

min

number

max

number

Returns

IntProvider

---

validTreePos()

validTreePos(world, position): boolean

Defined in: features/tree/shared.ts:169

Answers Java's TreeFeature.validTreePos: air, or a block trees are allowed to grow through.

Parameters

world

FeatureWorld

position

BlockPos

Returns

boolean

---

vegetationPatch()

vegetationPatch(config, waterlogged?): ConfiguredFeature

Defined in: features/caves.ts:562

A patch of ground with vegetation on it, Java's vegetation_patch.

surface decides which way is in: a floor patch carves down into the ground and grows up, and a ceiling patch does the reverse, which is how one implementation covers both the lush cave moss floor and its ceiling.

Parameters

config

VegetationPatchConfig

waterlogged?

boolean = false

Returns

ConfiguredFeature

---

veryBiasedToBottomHeight()

veryBiasedToBottomHeight(min, max, inner): HeightProvider

Defined in: providers/heightProvider.ts:118

A y weighted hard toward the bottom. Costs three draws.

Parameters

min

VerticalAnchor

max

VerticalAnchor

inner

number

Returns

HeightProvider

---

veryBiasedToBottomInt()

veryBiasedToBottomInt(min, max): IntProvider

Defined in: providers/valueProviders.ts:71

A value in [min, max] weighted hard toward min. Costs three draws.

Parameters

min

number

max

number

Returns

IntProvider

---

vines()

vines(): ConfiguredFeature

Defined in: features/simple.ts:632

Hangs a vine on the first face of the origin that has a block behind it.

Returns

ConfiguredFeature

---

voidStartPlatform()

voidStartPlatform(): ConfiguredFeature

Defined in: features/simple.ts:232

Builds the stone platform a player spawns on in a void world.

Returns

ConfiguredFeature

---

walkFeatures()

walkFeatures(root): Generator<ConfiguredFeature>

Defined in: features/Feature.ts:102

Walks a feature and everything it delegates to, depth first, including the root.

Parameters

root

ConfiguredFeature

Returns

Generator<ConfiguredFeature>

---

weightedListHeight()

weightedListHeight(entries): HeightProvider

Defined in: providers/heightProvider.ts:146

Picks a nested provider by weight, then draws from it.

Parameters

entries

readonly Weighted<HeightProvider>[]

Returns

HeightProvider

---

weightedListInt()

weightedListInt(entries): IntProvider

Defined in: providers/valueProviders.ts:127

Picks a nested provider by weight, then draws from it. Costs one draw plus the nested cost.

Parameters

entries

readonly Weighted<IntProvider>[]

Returns

IntProvider

---

weightedProvider()

weightedProvider(entries): BlockStateProvider

Defined in: providers/blockStateProvider.ts:61

Draws one of several states by weight. Costs one draw.

Parameters

entries

readonly Weighted<BlockState>[]

Returns

BlockStateProvider

---

weightedRandomSelector()

weightedRandomSelector(features): ConfiguredFeature

Defined in: features/simple.ts:74

Runs one placed feature drawn by weight.

Parameters

features

readonly object[]

Returns

ConfiguredFeature

---

withProperties()

withProperties(state, values): BlockState

Defined in: world/BlockState.ts:72

Returns a copy of state with several properties set at once.

Parameters

state

BlockState

values

Readonly<Record<string, string>>

Returns

BlockState

---

withProperty()

withProperty(state, key, value): BlockState

Defined in: world/BlockState.ts:68

Returns a copy of state with one property set, leaving the original untouched.

Parameters

state

BlockState

key

string

value

string

Returns

BlockState

---

withinManhattan()

withinManhattan(center, rangeX, rangeY, rangeZ): Generator<BlockPos>

Defined in: features/support.ts:79

Iterates a box in Java's BlockPos.withinBoxByManhattanDistance order.

It spirals outward by Manhattan distance, which is why delta_feature and netherrack_replace_blobs can stop at the first position past their radius instead of filtering the whole box.

Parameters

center

BlockPos

rangeX

number

rangeY

number

rangeZ

number

Returns

Generator<BlockPos>