hyperframes/docs/public/catalog/vendor/BufferGeometryUtils.json

{"text":"import {\n  BufferAttribute,\n  BufferGeometry,\n  Float32BufferAttribute,\n  InstancedBufferAttribute,\n  InterleavedBuffer,\n  InterleavedBufferAttribute,\n  TriangleFanDrawMode,\n  TriangleStripDrawMode,\n  TrianglesDrawMode,\n  Vector3,\n} from \"three\";\n\n/**\n * @module BufferGeometryUtils\n * @three_import import * as BufferGeometryUtils from 'three/addons/utils/BufferGeometryUtils.js';\n */\n\n/**\n * Computes vertex tangents using the MikkTSpace algorithm. MikkTSpace generates the same tangents consistently,\n * and is used in most modelling tools and normal map bakers. Use MikkTSpace for materials with normal maps,\n * because inconsistent tangents may lead to subtle visual issues in the normal map, particularly around mirrored\n * UV seams.\n *\n * In comparison to this method, {@link BufferGeometry#computeTangents} (a custom algorithm) generates tangents that\n * probably will not match the tangents in other software. The custom algorithm is sufficient for general use with a\n * custom material, and may be faster than MikkTSpace.\n *\n * Returns the original BufferGeometry. Indexed geometries will be de-indexed. Requires position, normal, and uv attributes.\n *\n * @param {BufferGeometry} geometry - The geometry to compute tangents for.\n * @param {Object} MikkTSpace - Instance of `examples/jsm/libs/mikktspace.module.js`, or `mikktspace` npm package.\n * Await `MikkTSpace.ready` before use.\n * @param {boolean} [negateSign=true] - Whether to negate the sign component (.w) of each tangent.\n * Required for normal map conventions in some formats, including glTF.\n * @return {BufferGeometry} The updated geometry.\n */\nfunction computeMikkTSpaceTangents(geometry, MikkTSpace, negateSign = true) {\n  if (!MikkTSpace || !MikkTSpace.isReady) {\n    throw new Error(\"BufferGeometryUtils: Initialized MikkTSpace library required.\");\n  }\n\n  if (\n    !geometry.hasAttribute(\"position\") ||\n    !geometry.hasAttribute(\"normal\") ||\n    !geometry.hasAttribute(\"uv\")\n  ) {\n    throw new Error(\n      'BufferGeometryUtils: Tangents require \"position\", \"normal\", and \"uv\" attributes.',\n    );\n  }\n\n  function getAttributeArray(attribute) {\n    if (attribute.normalized || attribute.isInterleavedBufferAttribute) {\n      const dstArray = new Float32Array(attribute.count * attribute.itemSize);\n\n      for (let i = 0, j = 0; i < attribute.count; i++) {\n        dstArray[j++] = attribute.getX(i);\n        dstArray[j++] = attribute.getY(i);\n\n        if (attribute.itemSize > 2) {\n          dstArray[j++] = attribute.getZ(i);\n        }\n      }\n\n      return dstArray;\n    }\n\n    if (attribute.array instanceof Float32Array) {\n      return attribute.array;\n    }\n\n    return new Float32Array(attribute.array);\n  }\n\n  // MikkTSpace algorithm requires non-indexed input.\n\n  const _geometry = geometry.index ? geometry.toNonIndexed() : geometry;\n\n  // Compute vertex tangents.\n\n  const tangents = MikkTSpace.generateTangents(\n    getAttributeArray(_geometry.attributes.position),\n    getAttributeArray(_geometry.attributes.normal),\n    getAttributeArray(_geometry.attributes.uv),\n  );\n\n  // Texture coordinate convention of glTF differs from the apparent\n  // default of the MikkTSpace library; .w component must be flipped.\n\n  if (negateSign) {\n    for (let i = 3; i < tangents.length; i += 4) {\n      tangents[i] *= -1;\n    }\n  }\n\n  //\n\n  _geometry.setAttribute(\"tangent\", new BufferAttribute(tangents, 4));\n\n  if (geometry !== _geometry) {\n    geometry.copy(_geometry);\n  }\n\n  return geometry;\n}\n\n/**\n * Merges a set of geometries into a single instance. All geometries must have compatible attributes.\n *\n * @param {Array<BufferGeometry>} geometries - The geometries to merge.\n * @param {boolean} [useGroups=false] - Whether to use groups or not.\n * @return {?BufferGeometry} The merged geometry. Returns `null` if the merge does not succeed.\n */\nfunction mergeGeometries(geometries, useGroups = false) {\n  const isIndexed = geometries[0].index !== null;\n\n  const attributesUsed = new Set(Object.keys(geometries[0].attributes));\n  const morphAttributesUsed = new Set(Object.keys(geometries[0].morphAttributes));\n\n  const attributes = {};\n  const morphAttributes = {};\n\n  const morphTargetsRelative = geometries[0].morphTargetsRelative;\n\n  const mergedGeometry = new BufferGeometry();\n\n  let offset = 0;\n\n  for (let i = 0; i < geometries.length; ++i) {\n    const geometry = geometries[i];\n    let attributesCount = 0;\n\n    // ensure that all geometries are indexed, or none\n\n    if (isIndexed !== (geometry.index !== null)) {\n      console.error(\n        \"THREE.BufferGeometryUtils: .mergeGeometries() failed with geometry at index \" +\n          i +\n          \". All geometries must have compatible attributes; make sure index attribute exists among all geometries, or in none of them.\",\n      );\n      return null;\n    }\n\n    // gather attributes, exit early if they're different\n\n    for (const name in geometry.attributes) {\n      if (!attributesUsed.has(name)) {\n        console.error(\n          \"THREE.BufferGeometryUtils: .mergeGeometries() failed with geometry at index \" +\n            i +\n            '. All geometries must have compatible attributes; make sure \"' +\n            name +\n            '\" attribute exists among all geometries, or in none of them.',\n        );\n        return null;\n      }\n\n      if (attributes[name] === undefined) attributes[name] = [];\n\n      attributes[name].push(geometry.attributes[name]);\n\n      attributesCount++;\n    }\n\n    // ensure geometries have the same number of attributes\n\n    if (attributesCount !== attributesUsed.size) {\n      console.error(\n        \"THREE.BufferGeometryUtils: .mergeGeometries() failed with geometry at index \" +\n          i +\n          \". Make sure all geometries have the same number of attributes.\",\n      );\n      return null;\n    }\n\n    // gather morph attributes, exit early if they're different\n\n    if (morphTargetsRelative !== geometry.morphTargetsRelative) {\n      console.error(\n        \"THREE.BufferGeometryUtils: .mergeGeometries() failed with geometry at index \" +\n          i +\n          \". .morphTargetsRelative must be consistent throughout all geometries.\",\n      );\n      return null;\n    }\n\n    for (const name in geometry.morphAttributes) {\n      if (!morphAttributesUsed.has(name)) {\n        console.error(\n          \"THREE.BufferGeometryUtils: .mergeGeometries() failed with geometry at index \" +\n            i +\n            \".  .morphAttributes must be consistent throughout all geometries.\",\n        );\n        return null;\n      }\n\n      if (morphAttributes[name] === undefined) morphAttributes[name] = [];\n\n      morphAttributes[name].push(geometry.morphAttributes[name]);\n    }\n\n    if (useGroups) {\n      let count;\n\n      if (isIndexed) {\n        count = geometry.index.count;\n      } else if (geometry.attributes.position !== undefined) {\n        count = geometry.attributes.position.count;\n      } else {\n        console.error(\n          \"THREE.BufferGeometryUtils: .mergeGeometries() failed with geometry at index \" +\n            i +\n            \". The geometry must have either an index or a position attribute\",\n        );\n        return null;\n      }\n\n      mergedGeometry.addGroup(offset, count, i);\n\n      offset += count;\n    }\n  }\n\n  // merge indices\n\n  if (isIndexed) {\n    let indexOffset = 0;\n    const mergedIndex = [];\n\n    for (let i = 0; i < geometries.length; ++i) {\n      const index = geometries[i].index;\n\n      for (let j = 0; j < index.count; ++j) {\n        mergedIndex.push(index.getX(j) + indexOffset);\n      }\n\n      indexOffset += geometries[i].attributes.position.count;\n    }\n\n    mergedGeometry.setIndex(mergedIndex);\n  }\n\n  // merge attributes\n\n  for (const name in attributes) {\n    const mergedAttribute = mergeAttributes(attributes[name]);\n\n    if (!mergedAttribute) {\n      console.error(\n        \"THREE.BufferGeometryUtils: .mergeGeometries() failed while trying to merge the \" +\n          name +\n          \" attribute.\",\n      );\n      return null;\n    }\n\n    mergedGeometry.setAttribute(name, mergedAttribute);\n  }\n\n  // merge morph attributes\n\n  for (const name in morphAttributes) {\n    const numMorphTargets = morphAttributes[name][0].length;\n\n    if (numMorphTargets === 0) break;\n\n    mergedGeometry.morphAttributes = mergedGeometry.morphAttributes || {};\n    mergedGeometry.morphAttributes[name] = [];\n\n    for (let i = 0; i < numMorphTargets; ++i) {\n      const morphAttributesToMerge = [];\n\n      for (let j = 0; j < morphAttributes[name].length; ++j) {\n        morphAttributesToMerge.push(morphAttributes[name][j][i]);\n      }\n\n      const mergedMorphAttribute = mergeAttributes(morphAttributesToMerge);\n\n      if (!mergedMorphAttribute) {\n        console.error(\n          \"THREE.BufferGeometryUtils: .mergeGeometries() failed while trying to merge the \" +\n            name +\n            \" morphAttribute.\",\n        );\n        return null;\n      }\n\n      mergedGeometry.morphAttributes[name].push(mergedMorphAttribute);\n    }\n  }\n\n  return mergedGeometry;\n}\n\n/**\n * Merges a set of attributes into a single instance. All attributes must have compatible properties and types.\n * Instances of {@link InterleavedBufferAttribute} are not supported.\n *\n * @param {Array<BufferAttribute>} attributes - The attributes to merge.\n * @return {?BufferAttribute} The merged attribute. Returns `null` if the merge does not succeed.\n */\nfunction mergeAttributes(attributes) {\n  let TypedArray;\n  let itemSize;\n  let normalized;\n  let gpuType = -1;\n  let arrayLength = 0;\n\n  for (let i = 0; i < attributes.length; ++i) {\n    const attribute = attributes[i];\n\n    if (TypedArray === undefined) TypedArray = attribute.array.constructor;\n    if (TypedArray !== attribute.array.constructor) {\n      console.error(\n        \"THREE.BufferGeometryUtils: .mergeAttributes() failed. BufferAttribute.array must be of consistent array types across matching attributes.\",\n      );\n      return null;\n    }\n\n    if (itemSize === undefined) itemSize = attribute.itemSize;\n    if (itemSize !== attribute.itemSize) {\n      console.error(\n        \"THREE.BufferGeometryUtils: .mergeAttributes() failed. BufferAttribute.itemSize must be consistent across matching attributes.\",\n      );\n      return null;\n    }\n\n    if (normalized === undefined) normalized = attribute.normalized;\n    if (normalized !== attribute.normalized) {\n      console.error(\n        \"THREE.BufferGeometryUtils: .mergeAttributes() failed. BufferAttribute.normalized must be consistent across matching attributes.\",\n      );\n      return null;\n    }\n\n    if (gpuType === -1) gpuType = attribute.gpuType;\n    if (gpuType !== attribute.gpuType) {\n      console.error(\n        \"THREE.BufferGeometryUtils: .mergeAttributes() failed. BufferAttribute.gpuType must be consistent across matching attributes.\",\n      );\n      return null;\n    }\n\n    arrayLength += attribute.count * itemSize;\n  }\n\n  const array = new TypedArray(arrayLength);\n  const result = new BufferAttribute(array, itemSize, normalized);\n  let offset = 0;\n\n  for (let i = 0; i < attributes.length; ++i) {\n    const attribute = attributes[i];\n    if (attribute.isInterleavedBufferAttribute) {\n      const tupleOffset = offset / itemSize;\n      for (let j = 0, l = attribute.count; j < l; j++) {\n        for (let c = 0; c < itemSize; c++) {\n          const value = attribute.getComponent(j, c);\n          result.setComponent(j + tupleOffset, c, value);\n        }\n      }\n    } else {\n      array.set(attribute.array, offset);\n    }\n\n    offset += attribute.count * itemSize;\n  }\n\n  if (gpuType !== undefined) {\n    result.gpuType = gpuType;\n  }\n\n  return result;\n}\n\n/**\n * Performs a deep clone of the given buffer attribute.\n *\n * @param {BufferAttribute} attribute - The attribute to clone.\n * @return {BufferAttribute} The cloned attribute.\n */\nfunction deepCloneAttribute(attribute) {\n  if (attribute.isInstancedInterleavedBufferAttribute || attribute.isInterleavedBufferAttribute) {\n    return deinterleaveAttribute(attribute);\n  }\n\n  if (attribute.isInstancedBufferAttribute) {\n    return new InstancedBufferAttribute().copy(attribute);\n  }\n\n  return new BufferAttribute().copy(attribute);\n}\n\n/**\n * Interleaves a set of attributes and returns a new array of corresponding attributes that share a\n * single {@link InterleavedBuffer} instance. All attributes must have compatible types.\n *\n * @param {Array<BufferAttribute>} attributes - The attributes to interleave.\n * @return {?Array<InterleavedBufferAttribute>} An array of interleaved attributes. If interleave does not succeed, the method returns `null`.\n */\nfunction interleaveAttributes(attributes) {\n  // Interleaves the provided attributes into an InterleavedBuffer and returns\n  // a set of InterleavedBufferAttributes for each attribute\n  let TypedArray;\n  let arrayLength = 0;\n  let stride = 0;\n\n  // calculate the length and type of the interleavedBuffer\n  for (let i = 0, l = attributes.length; i < l; ++i) {\n    const attribute = attributes[i];\n\n    if (TypedArray === undefined) TypedArray = attribute.array.constructor;\n    if (TypedArray !== attribute.array.constructor) {\n      console.error(\"AttributeBuffers of different types cannot be interleaved\");\n      return null;\n    }\n\n    arrayLength += attribute.array.length;\n    stride += attribute.itemSize;\n  }\n\n  // Create the set of buffer attributes\n  const interleavedBuffer = new InterleavedBuffer(new TypedArray(arrayLength), stride);\n  let offset = 0;\n  const res = [];\n  const getters = [\"getX\", \"getY\", \"getZ\", \"getW\"];\n  const setters = [\"setX\", \"setY\", \"setZ\", \"setW\"];\n\n  for (let j = 0, l = attributes.length; j < l; j++) {\n    const attribute = attributes[j];\n    const itemSize = attribute.itemSize;\n    const count = attribute.count;\n    const iba = new InterleavedBufferAttribute(\n      interleavedBuffer,\n      itemSize,\n      offset,\n      attribute.normalized,\n    );\n    res.push(iba);\n\n    offset += itemSize;\n\n    // Move the data for each attribute into the new interleavedBuffer\n    // at the appropriate offset\n    for (let c = 0; c < count; c++) {\n      for (let k = 0; k < itemSize; k++) {\n        iba[setters[k]](c, attribute[getters[k]](c));\n      }\n    }\n  }\n\n  return res;\n}\n\n/**\n * Returns a new, non-interleaved version of the given attribute.\n *\n * @param {InterleavedBufferAttribute} attribute - The interleaved attribute.\n * @return {BufferAttribute} The non-interleaved attribute.\n */\nfunction deinterleaveAttribute(attribute) {\n  const cons = attribute.data.array.constructor;\n  const count = attribute.count;\n  const itemSize = attribute.itemSize;\n  const normalized = attribute.normalized;\n\n  const array = new cons(count * itemSize);\n  let newAttribute;\n  if (attribute.isInstancedInterleavedBufferAttribute) {\n    newAttribute = new InstancedBufferAttribute(\n      array,\n      itemSize,\n      normalized,\n      attribute.meshPerAttribute,\n    );\n  } else {\n    newAttribute = new BufferAttribute(array, itemSize, normalized);\n  }\n\n  for (let i = 0; i < count; i++) {\n    newAttribute.setX(i, attribute.getX(i));\n\n    if (itemSize >= 2) {\n      newAttribute.setY(i, attribute.getY(i));\n    }\n\n    if (itemSize >= 3) {\n      newAttribute.setZ(i, attribute.getZ(i));\n    }\n\n    if (itemSize >= 4) {\n      newAttribute.setW(i, attribute.getW(i));\n    }\n  }\n\n  return newAttribute;\n}\n\n/**\n * Deinterleaves all attributes on the given geometry.\n *\n * @param {BufferGeometry} geometry - The geometry to deinterleave.\n */\nfunction deinterleaveGeometry(geometry) {\n  const attributes = geometry.attributes;\n  const morphTargets = geometry.morphTargets;\n  const attrMap = new Map();\n\n  for (const key in attributes) {\n    const attr = attributes[key];\n    if (attr.isInterleavedBufferAttribute) {\n      if (!attrMap.has(attr)) {\n        attrMap.set(attr, deinterleaveAttribute(attr));\n      }\n\n      attributes[key] = attrMap.get(attr);\n    }\n  }\n\n  for (const key in morphTargets) {\n    const attr = morphTargets[key];\n    if (attr.isInterleavedBufferAttribute) {\n      if (!attrMap.has(attr)) {\n        attrMap.set(attr, deinterleaveAttribute(attr));\n      }\n\n      morphTargets[key] = attrMap.get(attr);\n    }\n  }\n}\n\n/**\n * Returns the amount of bytes used by all attributes to represent the geometry.\n *\n * @param {BufferGeometry} geometry - The geometry.\n * @return {number} The estimate bytes used.\n */\nfunction estimateBytesUsed(geometry) {\n  // Return the estimated memory used by this geometry in bytes\n  // Calculate using itemSize, count, and BYTES_PER_ELEMENT to account\n  // for InterleavedBufferAttributes.\n  let mem = 0;\n  for (const name in geometry.attributes) {\n    const attr = geometry.getAttribute(name);\n    mem += attr.count * attr.itemSize * attr.array.BYTES_PER_ELEMENT;\n  }\n\n  const indices = geometry.getIndex();\n  mem += indices ? indices.count * indices.itemSize * indices.array.BYTES_PER_ELEMENT : 0;\n  return mem;\n}\n\n/**\n * Returns a new geometry with vertices for which all similar vertex attributes (within tolerance) are merged.\n *\n * @param {BufferGeometry} geometry - The geometry to merge vertices for.\n * @param {number} [tolerance=1e-4] - The tolerance value.\n * @return {BufferGeometry} - The new geometry with merged vertices.\n */\nfunction mergeVertices(geometry, tolerance = 1e-4) {\n  tolerance = Math.max(tolerance, Number.EPSILON);\n\n  // Generate an index buffer if the geometry doesn't have one, or optimize it\n  // if it's already available.\n  const hashToIndex = {};\n  const indices = geometry.getIndex();\n  const positions = geometry.getAttribute(\"position\");\n  const vertexCount = indices ? indices.count : positions.count;\n\n  // next value for triangle indices\n  let nextIndex = 0;\n\n  // attributes and new attribute arrays\n  const attributeNames = Object.keys(geometry.attributes);\n  const tmpAttributes = {};\n  const tmpMorphAttributes = {};\n  const newIndices = [];\n  const getters = [\"getX\", \"getY\", \"getZ\", \"getW\"];\n  const setters = [\"setX\", \"setY\", \"setZ\", \"setW\"];\n\n  // Initialize the arrays, allocating space conservatively. Extra\n  // space will be trimmed in the last step.\n  for (let i = 0, l = attributeNames.length; i < l; i++) {\n    const name = attributeNames[i];\n    const attr = geometry.attributes[name];\n\n    tmpAttributes[name] = new attr.constructor(\n      new attr.array.constructor(attr.count * attr.itemSize),\n      attr.itemSize,\n      attr.normalized,\n    );\n\n    const morphAttributes = geometry.morphAttributes[name];\n    if (morphAttributes) {\n      if (!tmpMorphAttributes[name]) tmpMorphAttributes[name] = [];\n      morphAttributes.forEach((morphAttr, i) => {\n        const array = new morphAttr.array.constructor(morphAttr.count * morphAttr.itemSize);\n        tmpMorphAttributes[name][i] = new morphAttr.constructor(\n          array,\n          morphAttr.itemSize,\n          morphAttr.normalized,\n        );\n      });\n    }\n  }\n\n  // convert the error tolerance to an amount of decimal places to truncate to\n  const halfTolerance = tolerance * 0.5;\n  const exponent = Math.log10(1 / tolerance);\n  const hashMultiplier = Math.pow(10, exponent);\n  const hashAdditive = halfTolerance * hashMultiplier;\n  for (let i = 0; i < vertexCount; i++) {\n    const index = indices ? indices.getX(i) : i;\n\n    // Generate a hash for the vertex attributes at the current index 'i'\n    let hash = \"\";\n    for (let j = 0, l = attributeNames.length; j < l; j++) {\n      const name = attributeNames[j];\n      const attribute = geometry.getAttribute(name);\n      const itemSize = attribute.itemSize;\n\n      for (let k = 0; k < itemSize; k++) {\n        // double tilde truncates the decimal value\n        hash += `${~~(attribute[getters[k]](index) * hashMultiplier + hashAdditive)},`;\n      }\n    }\n\n    // Add another reference to the vertex if it's already\n    // used by another index\n    if (hash in hashToIndex) {\n      newIndices.push(hashToIndex[hash]);\n    } else {\n      // copy data to the new index in the temporary attributes\n      for (let j = 0, l = attributeNames.length; j < l; j++) {\n        const name = attributeNames[j];\n        const attribute = geometry.getAttribute(name);\n        const morphAttributes = geometry.morphAttributes[name];\n        const itemSize = attribute.itemSize;\n        const newArray = tmpAttributes[name];\n        const newMorphArrays = tmpMorphAttributes[name];\n\n        for (let k = 0; k < itemSize; k++) {\n          const getterFunc = getters[k];\n          const setterFunc = setters[k];\n          newArray[setterFunc](nextIndex, attribute[getterFunc](index));\n\n          if (morphAttributes) {\n            for (let m = 0, ml = morphAttributes.length; m < ml; m++) {\n              newMorphArrays[m][setterFunc](nextIndex, morphAttributes[m][getterFunc](index));\n            }\n          }\n        }\n      }\n\n      hashToIndex[hash] = nextIndex;\n      newIndices.push(nextIndex);\n      nextIndex++;\n    }\n  }\n\n  // generate result BufferGeometry\n  const result = geometry.clone();\n  for (const name in geometry.attributes) {\n    const tmpAttribute = tmpAttributes[name];\n\n    result.setAttribute(\n      name,\n      new tmpAttribute.constructor(\n        tmpAttribute.array.slice(0, nextIndex * tmpAttribute.itemSize),\n        tmpAttribute.itemSize,\n        tmpAttribute.normalized,\n      ),\n    );\n\n    if (!(name in tmpMorphAttributes)) continue;\n\n    for (let j = 0; j < tmpMorphAttributes[name].length; j++) {\n      const tmpMorphAttribute = tmpMorphAttributes[name][j];\n\n      result.morphAttributes[name][j] = new tmpMorphAttribute.constructor(\n        tmpMorphAttribute.array.slice(0, nextIndex * tmpMorphAttribute.itemSize),\n        tmpMorphAttribute.itemSize,\n        tmpMorphAttribute.normalized,\n      );\n    }\n  }\n\n  // indices\n\n  result.setIndex(newIndices);\n\n  return result;\n}\n\n/**\n * Returns a new indexed geometry based on `TrianglesDrawMode` draw mode.\n * This mode corresponds to the `gl.TRIANGLES` primitive in WebGL.\n *\n * @param {BufferGeometry} geometry - The geometry to convert.\n * @param {number} drawMode - The current draw mode.\n * @return {BufferGeometry} The new geometry using `TrianglesDrawMode`.\n */\nfunction toTrianglesDrawMode(geometry, drawMode) {\n  if (drawMode === TrianglesDrawMode) {\n    console.warn(\n      \"THREE.BufferGeometryUtils.toTrianglesDrawMode(): Geometry already defined as triangles.\",\n    );\n    return geometry;\n  }\n\n  if (drawMode === TriangleFanDrawMode || drawMode === TriangleStripDrawMode) {\n    let index = geometry.getIndex();\n\n    // generate index if not present\n\n    if (index === null) {\n      const indices = [];\n\n      const position = geometry.getAttribute(\"position\");\n\n      if (position !== undefined) {\n        for (let i = 0; i < position.count; i++) {\n          indices.push(i);\n        }\n\n        geometry.setIndex(indices);\n        index = geometry.getIndex();\n      } else {\n        console.error(\n          \"THREE.BufferGeometryUtils.toTrianglesDrawMode(): Undefined position attribute. Processing not possible.\",\n        );\n        return geometry;\n      }\n    }\n\n    //\n\n    const numberOfTriangles = index.count - 2;\n    const newIndices = [];\n\n    if (drawMode === TriangleFanDrawMode) {\n      // gl.TRIANGLE_FAN\n\n      for (let i = 1; i <= numberOfTriangles; i++) {\n        newIndices.push(index.getX(0));\n        newIndices.push(index.getX(i));\n        newIndices.push(index.getX(i + 1));\n      }\n    } else {\n      // gl.TRIANGLE_STRIP\n\n      for (let i = 0; i < numberOfTriangles; i++) {\n        if (i % 2 === 0) {\n          newIndices.push(index.getX(i));\n          newIndices.push(index.getX(i + 1));\n          newIndices.push(index.getX(i + 2));\n        } else {\n          newIndices.push(index.getX(i + 2));\n          newIndices.push(index.getX(i + 1));\n          newIndices.push(index.getX(i));\n        }\n      }\n    }\n\n    if (newIndices.length / 3 !== numberOfTriangles) {\n      console.error(\n        \"THREE.BufferGeometryUtils.toTrianglesDrawMode(): Unable to generate correct amount of triangles.\",\n      );\n    }\n\n    // build final geometry\n\n    const newGeometry = geometry.clone();\n    newGeometry.setIndex(newIndices);\n    newGeometry.clearGroups();\n\n    return newGeometry;\n  } else {\n    console.error(\"THREE.BufferGeometryUtils.toTrianglesDrawMode(): Unknown draw mode:\", drawMode);\n    return geometry;\n  }\n}\n\n/**\n * Calculates the morphed attributes of a morphed/skinned BufferGeometry.\n *\n * Helpful for Raytracing or Decals (i.e. a `DecalGeometry` applied to a morphed Object with a `BufferGeometry`\n * will use the original `BufferGeometry`, not the morphed/skinned one, generating an incorrect result.\n * Using this function to create a shadow `Object3`D the `DecalGeometry` can be correctly generated).\n *\n * @param {Mesh|Line|Points} object - The 3D object to compute morph attributes for.\n * @return {Object} An object with original position/normal attributes and morphed ones.\n */\nfunction computeMorphedAttributes(object) {\n  const _vA = new Vector3();\n  const _vB = new Vector3();\n  const _vC = new Vector3();\n\n  const _tempA = new Vector3();\n  const _tempB = new Vector3();\n  const _tempC = new Vector3();\n\n  const _morphA = new Vector3();\n  const _morphB = new Vector3();\n  const _morphC = new Vector3();\n\n  function _calculateMorphedAttributeData(\n    object,\n    attribute,\n    morphAttribute,\n    morphTargetsRelative,\n    a,\n    b,\n    c,\n    modifiedAttributeArray,\n  ) {\n    _vA.fromBufferAttribute(attribute, a);\n    _vB.fromBufferAttribute(attribute, b);\n    _vC.fromBufferAttribute(attribute, c);\n\n    const morphInfluences = object.morphTargetInfluences;\n\n    if (morphAttribute && morphInfluences) {\n      _morphA.set(0, 0, 0);\n      _morphB.set(0, 0, 0);\n      _morphC.set(0, 0, 0);\n\n      for (let i = 0, il = morphAttribute.length; i < il; i++) {\n        const influence = morphInfluences[i];\n        const morph = morphAttribute[i];\n\n        if (influence === 0) continue;\n\n        _tempA.fromBufferAttribute(morph, a);\n        _tempB.fromBufferAttribute(morph, b);\n        _tempC.fromBufferAttribute(morph, c);\n\n        if (morphTargetsRelative) {\n          _morphA.addScaledVector(_tempA, influence);\n          _morphB.addScaledVector(_tempB, influence);\n          _morphC.addScaledVector(_tempC, influence);\n        } else {\n          _morphA.addScaledVector(_tempA.sub(_vA), influence);\n          _morphB.addScaledVector(_tempB.sub(_vB), influence);\n          _morphC.addScaledVector(_tempC.sub(_vC), influence);\n        }\n      }\n\n      _vA.add(_morphA);\n      _vB.add(_morphB);\n      _vC.add(_morphC);\n    }\n\n    if (object.isSkinnedMesh) {\n      object.applyBoneTransform(a, _vA);\n      object.applyBoneTransform(b, _vB);\n      object.applyBoneTransform(c, _vC);\n    }\n\n    modifiedAttributeArray[a * 3 + 0] = _vA.x;\n    modifiedAttributeArray[a * 3 + 1] = _vA.y;\n    modifiedAttributeArray[a * 3 + 2] = _vA.z;\n    modifiedAttributeArray[b * 3 + 0] = _vB.x;\n    modifiedAttributeArray[b * 3 + 1] = _vB.y;\n    modifiedAttributeArray[b * 3 + 2] = _vB.z;\n    modifiedAttributeArray[c * 3 + 0] = _vC.x;\n    modifiedAttributeArray[c * 3 + 1] = _vC.y;\n    modifiedAttributeArray[c * 3 + 2] = _vC.z;\n  }\n\n  const geometry = object.geometry;\n  const material = object.material;\n\n  let a, b, c;\n  const index = geometry.index;\n  const positionAttribute = geometry.attributes.position;\n  const morphPosition = geometry.morphAttributes.position;\n  const morphTargetsRelative = geometry.morphTargetsRelative;\n  const normalAttribute = geometry.attributes.normal;\n  const morphNormal = geometry.morphAttributes.position;\n\n  const groups = geometry.groups;\n  const drawRange = geometry.drawRange;\n  let i, j, il, jl;\n  let group;\n  let start, end;\n\n  const modifiedPosition = new Float32Array(positionAttribute.count * positionAttribute.itemSize);\n  const modifiedNormal = new Float32Array(normalAttribute.count * normalAttribute.itemSize);\n\n  if (index !== null) {\n    // indexed buffer geometry\n\n    if (Array.isArray(material)) {\n      for (i = 0, il = groups.length; i < il; i++) {\n        group = groups[i];\n\n        start = Math.max(group.start, drawRange.start);\n        end = Math.min(group.start + group.count, drawRange.start + drawRange.count);\n\n        for (j = start, jl = end; j < jl; j += 3) {\n          a = index.getX(j);\n          b = index.getX(j + 1);\n          c = index.getX(j + 2);\n\n          _calculateMorphedAttributeData(\n            object,\n            positionAttribute,\n            morphPosition,\n            morphTargetsRelative,\n            a,\n            b,\n            c,\n            modifiedPosition,\n          );\n\n          _calculateMorphedAttributeData(\n            object,\n            normalAttribute,\n            morphNormal,\n            morphTargetsRelative,\n            a,\n            b,\n            c,\n            modifiedNormal,\n          );\n        }\n      }\n    } else {\n      start = Math.max(0, drawRange.start);\n      end = Math.min(index.count, drawRange.start + drawRange.count);\n\n      for (i = start, il = end; i < il; i += 3) {\n        a = index.getX(i);\n        b = index.getX(i + 1);\n        c = index.getX(i + 2);\n\n        _calculateMorphedAttributeData(\n          object,\n          positionAttribute,\n          morphPosition,\n          morphTargetsRelative,\n          a,\n          b,\n          c,\n          modifiedPosition,\n        );\n\n        _calculateMorphedAttributeData(\n          object,\n          normalAttribute,\n          morphNormal,\n          morphTargetsRelative,\n          a,\n          b,\n          c,\n          modifiedNormal,\n        );\n      }\n    }\n  } else {\n    // non-indexed buffer geometry\n\n    if (Array.isArray(material)) {\n      for (i = 0, il = groups.length; i < il; i++) {\n        group = groups[i];\n\n        start = Math.max(group.start, drawRange.start);\n        end = Math.min(group.start + group.count, drawRange.start + drawRange.count);\n\n        for (j = start, jl = end; j < jl; j += 3) {\n          a = j;\n          b = j + 1;\n          c = j + 2;\n\n          _calculateMorphedAttributeData(\n            object,\n            positionAttribute,\n            morphPosition,\n            morphTargetsRelative,\n            a,\n            b,\n            c,\n            modifiedPosition,\n          );\n\n          _calculateMorphedAttributeData(\n            object,\n            normalAttribute,\n            morphNormal,\n            morphTargetsRelative,\n            a,\n            b,\n            c,\n            modifiedNormal,\n          );\n        }\n      }\n    } else {\n      start = Math.max(0, drawRange.start);\n      end = Math.min(positionAttribute.count, drawRange.start + drawRange.count);\n\n      for (i = start, il = end; i < il; i += 3) {\n        a = i;\n        b = i + 1;\n        c = i + 2;\n\n        _calculateMorphedAttributeData(\n          object,\n          positionAttribute,\n          morphPosition,\n          morphTargetsRelative,\n          a,\n          b,\n          c,\n          modifiedPosition,\n        );\n\n        _calculateMorphedAttributeData(\n          object,\n          normalAttribute,\n          morphNormal,\n          morphTargetsRelative,\n          a,\n          b,\n          c,\n          modifiedNormal,\n        );\n      }\n    }\n  }\n\n  const morphedPositionAttribute = new Float32BufferAttribute(modifiedPosition, 3);\n  const morphedNormalAttribute = new Float32BufferAttribute(modifiedNormal, 3);\n\n  return {\n    positionAttribute: positionAttribute,\n    normalAttribute: normalAttribute,\n    morphedPositionAttribute: morphedPositionAttribute,\n    morphedNormalAttribute: morphedNormalAttribute,\n  };\n}\n\n/**\n * Merges the {@link BufferGeometry#groups} for the given geometry.\n *\n * @param {BufferGeometry} geometry - The geometry to modify.\n * @return {BufferGeometry} - The updated geometry\n */\nfunction mergeGroups(geometry) {\n  if (geometry.groups.length === 0) {\n    console.warn(\n      \"THREE.BufferGeometryUtils.mergeGroups(): No groups are defined. Nothing to merge.\",\n    );\n    return geometry;\n  }\n\n  let groups = geometry.groups;\n\n  // sort groups by material index\n\n  groups = groups.sort((a, b) => {\n    if (a.materialIndex !== b.materialIndex) return a.materialIndex - b.materialIndex;\n\n    return a.start - b.start;\n  });\n\n  // create index for non-indexed geometries\n\n  if (geometry.getIndex() === null) {\n    const positionAttribute = geometry.getAttribute(\"position\");\n    const indices = [];\n\n    for (let i = 0; i < positionAttribute.count; i += 3) {\n      indices.push(i, i + 1, i + 2);\n    }\n\n    geometry.setIndex(indices);\n  }\n\n  // sort index\n\n  const index = geometry.getIndex();\n\n  const newIndices = [];\n\n  for (let i = 0; i < groups.length; i++) {\n    const group = groups[i];\n\n    const groupStart = group.start;\n    const groupLength = groupStart + group.count;\n\n    for (let j = groupStart; j < groupLength; j++) {\n      newIndices.push(index.getX(j));\n    }\n  }\n\n  geometry.dispose(); // Required to force buffer recreation\n  geometry.setIndex(newIndices);\n\n  // update groups indices\n\n  let start = 0;\n\n  for (let i = 0; i < groups.length; i++) {\n    const group = groups[i];\n\n    group.start = start;\n    start += group.count;\n  }\n\n  // merge groups\n\n  let currentGroup = groups[0];\n\n  geometry.groups = [currentGroup];\n\n  for (let i = 1; i < groups.length; i++) {\n    const group = groups[i];\n\n    if (currentGroup.materialIndex === group.materialIndex) {\n      currentGroup.count += group.count;\n    } else {\n      currentGroup = group;\n      geometry.groups.push(currentGroup);\n    }\n  }\n\n  return geometry;\n}\n\n/**\n * Modifies the supplied geometry if it is non-indexed, otherwise creates a new,\n * non-indexed geometry. Returns the geometry with smooth normals everywhere except\n * faces that meet at an angle greater than the crease angle.\n *\n * @param {BufferGeometry} geometry - The geometry to modify.\n * @param {number} [creaseAngle=Math.PI/3] - The crease angle in radians.\n * @return {BufferGeometry} - The updated geometry\n */\nfunction toCreasedNormals(geometry, creaseAngle = Math.PI / 3 /* 60 degrees */) {\n  const creaseDot = Math.cos(creaseAngle);\n  const hashMultiplier = (1 + 1e-10) * 1e2;\n\n  // reusable vectors\n  const verts = [new Vector3(), new Vector3(), new Vector3()];\n  const tempVec1 = new Vector3();\n  const tempVec2 = new Vector3();\n  const tempNorm = new Vector3();\n  const tempNorm2 = new Vector3();\n\n  // hashes a vector\n  function hashVertex(v) {\n    const x = ~~(v.x * hashMultiplier);\n    const y = ~~(v.y * hashMultiplier);\n    const z = ~~(v.z * hashMultiplier);\n    return `${x},${y},${z}`;\n  }\n\n  // BufferGeometry.toNonIndexed() warns if the geometry is non-indexed\n  // and returns the original geometry\n  const resultGeometry = geometry.index ? geometry.toNonIndexed() : geometry;\n  const posAttr = resultGeometry.attributes.position;\n  const vertexMap = {};\n\n  // find all the normals shared by commonly located vertices\n  for (let i = 0, l = posAttr.count / 3; i < l; i++) {\n    const i3 = 3 * i;\n    const a = verts[0].fromBufferAttribute(posAttr, i3 + 0);\n    const b = verts[1].fromBufferAttribute(posAttr, i3 + 1);\n    const c = verts[2].fromBufferAttribute(posAttr, i3 + 2);\n\n    tempVec1.subVectors(c, b);\n    tempVec2.subVectors(a, b);\n\n    // add the normal to the map for all vertices\n    const normal = new Vector3().crossVectors(tempVec1, tempVec2).normalize();\n    for (let n = 0; n < 3; n++) {\n      const vert = verts[n];\n      const hash = hashVertex(vert);\n      if (!(hash in vertexMap)) {\n        vertexMap[hash] = [];\n      }\n\n      vertexMap[hash].push(normal);\n    }\n  }\n\n  // average normals from all vertices that share a common location if they are within the\n  // provided crease threshold\n  const normalArray = new Float32Array(posAttr.count * 3);\n  const normAttr = new BufferAttribute(normalArray, 3, false);\n  for (let i = 0, l = posAttr.count / 3; i < l; i++) {\n    // get the face normal for this vertex\n    const i3 = 3 * i;\n    const a = verts[0].fromBufferAttribute(posAttr, i3 + 0);\n    const b = verts[1].fromBufferAttribute(posAttr, i3 + 1);\n    const c = verts[2].fromBufferAttribute(posAttr, i3 + 2);\n\n    tempVec1.subVectors(c, b);\n    tempVec2.subVectors(a, b);\n\n    tempNorm.crossVectors(tempVec1, tempVec2).normalize();\n\n    // average all normals that meet the threshold and set the normal value\n    for (let n = 0; n < 3; n++) {\n      const vert = verts[n];\n      const hash = hashVertex(vert);\n      const otherNormals = vertexMap[hash];\n      tempNorm2.set(0, 0, 0);\n\n      for (let k = 0, lk = otherNormals.length; k < lk; k++) {\n        const otherNorm = otherNormals[k];\n        if (tempNorm.dot(otherNorm) > creaseDot) {\n          tempNorm2.add(otherNorm);\n        }\n      }\n\n      tempNorm2.normalize();\n      normAttr.setXYZ(i3 + n, tempNorm2.x, tempNorm2.y, tempNorm2.z);\n    }\n  }\n\n  resultGeometry.setAttribute(\"normal\", normAttr);\n  return resultGeometry;\n}\n\nexport {\n  computeMikkTSpaceTangents,\n  mergeGeometries,\n  mergeAttributes,\n  deepCloneAttribute,\n  deinterleaveAttribute,\n  deinterleaveGeometry,\n  interleaveAttributes,\n  estimateBytesUsed,\n  mergeVertices,\n  toTrianglesDrawMode,\n  computeMorphedAttributes,\n  mergeGroups,\n  toCreasedNormals,\n};\n"}