Support Minecraft 26.1.2 chunk fluid counts

package.json

@@ -43,6 +43,7 @@
     "typescript": "^5.0.4"
   },
   "dependencies": {
+    "minecraft-data": "github:mneuhaus/node-minecraft-data#add-26.1.2-data-wrapper",
     "prismarine-biome": "^1.2.0",
     "prismarine-block": "^1.14.1",
     "prismarine-nbt": "^2.2.1",

src/index.js

@@ -13,7 +13,8 @@ const chunkImplementations = {
     1.18: require('./pc/1.18/chunk'),
     1.19: require('./pc/1.18/chunk'),
     '1.20': require('./pc/1.18/chunk'),
-    1.21: require('./pc/1.18/chunk')
+    1.21: require('./pc/1.18/chunk'),
+    26.1: require('./pc/1.18/chunk')
   },
   bedrock: {
     0.14: require('./bedrock/0.14/chunk'),

src/pc/1.18/ChunkColumn.js

@@ -13,6 +13,19 @@ const CAVES_UPDATE_WORLD_HEIGHT = 384
 module.exports = (Block, mcData) => {
   // 1.21.5+ writes no size prefix before chunk containers, it's computed dynamically to save 1 byte
   const noSizePrefix = mcData.version['>=']('1.21.5')
+  // 26.1.2 serializes a fluid-count short after nonEmptyBlockCount in each section.
+  const hasFluidCount = mcData.version.minecraftVersion === '26.1.2'
+  const fluidStateCache = new Map()
+  const fluidBlockNames = new Set(['water', 'lava', 'seagrass', 'tall_seagrass', 'kelp', 'kelp_plant', 'bubble_column'])
+  function hasFluidState (stateId) {
+    if (!stateId) return false
+    if (!fluidStateCache.has(stateId)) {
+      const block = Block.fromStateId(stateId)
+      fluidStateCache.set(stateId, fluidBlockNames.has(block.name) || block.isWaterlogged === true)
+    }
+    return fluidStateCache.get(stateId)
+  }
+
   return class ChunkColumn extends CommonChunkColumn {
     static get section () { return ChunkSection }
     constructor (options) {
@@ -24,7 +37,7 @@ module.exports = (Block, mcData) => {
       this.maxBitsPerBiome = neededBits(Object.values(mcData.biomes).length)
 
       this.sections = options?.sections ?? Array.from(
-        { length: this.numSections }, _ => new ChunkSection({ noSizePrefix, maxBitsPerBlock: this.maxBitsPerBlock })
+        { length: this.numSections }, _ => new ChunkSection({ noSizePrefix, hasFluidCount, maxBitsPerBlock: this.maxBitsPerBlock })
       )
       this.biomes = options?.biomes ?? Array.from(
         { length: this.numSections }, _ => new BiomeSection({ noSizePrefix })
@@ -180,7 +193,16 @@ module.exports = (Block, mcData) => {
 
     setBlockStateId (pos, stateId) {
       const section = this.sections[(pos.y - this.minY) >> 4]
-      if (section) { section.set(toSectionPos(pos, this.minY), stateId) }
+      if (section) {
+        const sectionPos = toSectionPos(pos, this.minY)
+        if (hasFluidCount) {
+          const oldStateId = section.get(sectionPos)
+          const oldHasFluid = hasFluidState(oldStateId)
+          const newHasFluid = hasFluidState(stateId)
+          if (oldHasFluid !== newHasFluid) section.fluidCount += newHasFluid ? 1 : -1
+        }
+        section.set(sectionPos, stateId)
+      }
     }
 
     setBlockLight (pos, light) {
@@ -252,7 +274,7 @@ module.exports = (Block, mcData) => {
     load (data) {
       const reader = SmartBuffer.fromBuffer(data)
       for (let i = 0; i < this.numSections; ++i) {
-        this.sections[i] = ChunkSection.read(reader, this.maxBitsPerBlock, noSizePrefix)
+        this.sections[i] = ChunkSection.read(reader, this.maxBitsPerBlock, noSizePrefix, hasFluidCount)
         this.biomes[i] = BiomeSection.read(reader, this.maxBitsPerBiome, noSizePrefix)
       }
     }
@@ -317,6 +339,7 @@ module.exports = (Block, mcData) => {
       const raiseUnknownBiome = biome => { throw new Error(`Failed to map ${JSON.stringify(biome)} to a biome ID`) }
       this.sections[y + minCY] = ChunkSection.fromLocalPalette({
         noSizePrefix,
+        hasFluidCount,
         data: BitArray.fromLongArray(blockStates.data || {}, blockStates.bitsPerBlock),
         palette: blockStates.palette
           .map(e => Block.fromProperties(e.Name.replace('minecraft:', ''), e.Properties || {}) ?? raiseUnknownBlock(e))

src/pc/common/PaletteChunkSection.js

@@ -12,6 +12,8 @@ function getBlockIndex (pos) {
 class ChunkSection {
   constructor (options) {
     this.noSizePrefix = options?.noSizePrefix // 1.21.5+ writes no size prefix before chunk containers, it's computed dynamically to save 1 byte
+    this.hasFluidCount = options?.hasFluidCount ?? false
+    this.fluidCount = options?.fluidCount ?? 0
     this.data = options?.data
     if (!this.data) {
       const value = options?.singleValue ?? 0
@@ -26,6 +28,7 @@ class ChunkSection {
       this.solidBlockCount = value ? constants.BLOCK_SECTION_VOLUME : 0
     } else {
       this.solidBlockCount = options?.solidBlockCount ?? 0
+      this.fluidCount = options?.fluidCount ?? 0
       if (options?.solidBlockCount == null) {
         for (let i = 0; i < constants.BLOCK_SECTION_VOLUME; ++i) {
           if (this.data.get(i)) { this.solidBlockCount++ }
@@ -38,15 +41,19 @@ class ChunkSection {
   toJson () {
     return JSON.stringify({
       data: this.data.toJson(),
-      solidBlockCount: this.solidBlockCount
+      solidBlockCount: this.solidBlockCount,
+      hasFluidCount: this.hasFluidCount,
+      fluidCount: this.fluidCount
     })
   }
 
   static fromJson (j) {
     const parsed = JSON.parse(j)
     return new ChunkSection({
       data: paletteContainer.fromJson(parsed.data),
-      solidBlockCount: parsed.solidBlockCount
+      solidBlockCount: parsed.solidBlockCount,
+      hasFluidCount: parsed.hasFluidCount,
+      fluidCount: parsed.fluidCount
     })
   }
 
@@ -74,12 +81,15 @@ class ChunkSection {
 
   write (smartBuffer) {
     smartBuffer.writeInt16BE(this.solidBlockCount)
+    if (this.hasFluidCount) smartBuffer.writeInt16BE(this.fluidCount ?? 0)
     this.data.write(smartBuffer)
   }
 
-  static fromLocalPalette ({ data, palette, noSizePrefix }) {
+  static fromLocalPalette ({ data, palette, noSizePrefix, hasFluidCount, fluidCount }) {
     return new ChunkSection({
       noSizePrefix,
+      hasFluidCount,
+      fluidCount,
       data: palette.length === 1
         ? new SingleValueContainer({
           noSizePrefix,
@@ -96,15 +106,18 @@ class ChunkSection {
     })
   }
 
-  static read (smartBuffer, maxBitsPerBlock = constants.GLOBAL_BITS_PER_BLOCK, noSizePrefix) {
+  static read (smartBuffer, maxBitsPerBlock = constants.GLOBAL_BITS_PER_BLOCK, noSizePrefix, hasFluidCount = false) {
     const solidBlockCount = smartBuffer.readInt16BE()
+    const fluidCount = hasFluidCount ? smartBuffer.readInt16BE() : 0
     const bitsPerBlock = smartBuffer.readUInt8()
     if (bitsPerBlock > 16) throw new Error(`Bits per block is too big: ${bitsPerBlock}`)
     // Case 1: Single Value Container (all blocks in the section are the same)
     if (bitsPerBlock === 0) {
       const section = new ChunkSection({
         noSizePrefix,
+        hasFluidCount,
         solidBlockCount,
+        fluidCount,
         singleValue: varInt.read(smartBuffer),
         maxBitsPerBlock
       })
@@ -116,7 +129,9 @@ class ChunkSection {
     if (bitsPerBlock > constants.MAX_BITS_PER_BLOCK) {
       return new ChunkSection({
         noSizePrefix,
+        hasFluidCount,
         solidBlockCount,
+        fluidCount,
         data: new DirectPaletteContainer({
           noSizePrefix,
           bitsPerValue: maxBitsPerBlock,
@@ -134,7 +149,9 @@ class ChunkSection {
 
     return new ChunkSection({
       noSizePrefix,
+      hasFluidCount,
       solidBlockCount,
+      fluidCount,
       data: new IndirectPaletteContainer({
         noSizePrefix,
         bitsPerValue: bitsPerBlock,

test/ChunkColumn.test.js

@@ -205,5 +205,34 @@ for (const version of allVersions) {
         assert.strictEqual(biomeId, column.getBiomeId(pos))
       })
     }
+
+    if (version === '26.1.2') {
+      it('updates section fluid count when block states change', () => {
+        const column = new ChunkColumn()
+        const pos = new Vec3(0, 0, 0)
+        const section = column.sections[(pos.y - column.minY) >> 4]
+        const airStateId = registry.blocksByName.air.defaultState
+        const waterStateId = registry.blocksByName.water.defaultState
+        const oakStairs = registry.blocksByName.oak_stairs
+        let waterloggedStairsStateId
+        let dryStairsStateId
+
+        for (let stateId = oakStairs.minStateId; stateId <= oakStairs.maxStateId; stateId++) {
+          const block = Block.fromStateId(stateId)
+          if (block.isWaterlogged === true && waterloggedStairsStateId === undefined) waterloggedStairsStateId = stateId
+          if (block.isWaterlogged === false && dryStairsStateId === undefined) dryStairsStateId = stateId
+        }
+
+        assert.strictEqual(section.fluidCount, 0)
+        column.setBlockStateId(pos, waterStateId)
+        assert.strictEqual(section.fluidCount, 1)
+        column.setBlockStateId(pos.offset(1, 0, 0), waterloggedStairsStateId)
+        assert.strictEqual(section.fluidCount, 2)
+        column.setBlockStateId(pos, airStateId)
+        assert.strictEqual(section.fluidCount, 1)
+        column.setBlockStateId(pos.offset(1, 0, 0), dryStairsStateId)
+        assert.strictEqual(section.fluidCount, 0)
+      })
+    }
   })
 }

test/ChunkSection.test.js

@@ -2,7 +2,9 @@
 
 const Vec3 = require('vec3').Vec3
 const ChunkSection = require('../src/pc/1.13/ChunkSection')
+const PaletteChunkSection = require('../src/pc/common/PaletteChunkSection')
 const constants = require('../src/pc/common/constants')
+const SmartBuffer = require('smart-buffer').SmartBuffer
 const assert = require('assert')
 
 describe('pc 1.13 ChunkSection', () => {
@@ -37,3 +39,26 @@ describe('pc 1.13 ChunkSection', () => {
     }
   })
 })
+
+describe('pc palette ChunkSection', () => {
+  it('preserves fluid count through binary serialization', () => {
+    const section = new PaletteChunkSection({ hasFluidCount: true, fluidCount: 9 })
+    const writer = new SmartBuffer()
+
+    section.write(writer)
+
+    const read = PaletteChunkSection.read(SmartBuffer.fromBuffer(writer.toBuffer()), undefined, undefined, true)
+    assert.strictEqual(read.hasFluidCount, true)
+    assert.strictEqual(read.fluidCount, 9)
+  })
+
+  it('preserves fluid count through JSON serialization', () => {
+    const section = new PaletteChunkSection({ hasFluidCount: true, fluidCount: 4 })
+
+    const read = PaletteChunkSection.fromJson(section.toJson())
+
+    assert.strictEqual(read.hasFluidCount, true)
+    assert.strictEqual(read.fluidCount, 4)
+    assert.strictEqual(read.toJson(), section.toJson())
+  })
+})

test/versions.js

@@ -1,5 +1,5 @@
 const fs = require('fs')
-const pcVersions = ['bedrock_0.14', 'bedrock_1.0', '1.8', '1.9', '1.10', '1.11', '1.12', '1.13.2', '1.14.4', '1.15.2', '1.16.1', '1.17', '1.18', '1.19', '1.20']
+const pcVersions = ['bedrock_0.14', 'bedrock_1.0', '1.8', '1.9', '1.10', '1.11', '1.12', '1.13.2', '1.14.4', '1.15.2', '1.16.1', '1.17', '1.18', '1.19', '1.20', '26.1.2']
 const bedrockVersions = ['bedrock_1.16.220', 'bedrock_1.17.40', 'bedrock_1.18.0']
 const allVersions = [...bedrockVersions, ...pcVersions]