support gltf meshes in 3d scene

nicegui/elements/lib/three/modules/BufferGeometryUtils.js

@@ -0,0 +1,1371 @@
+import {
+	BufferAttribute,
+	BufferGeometry,
+	Float32BufferAttribute,
+	InstancedBufferAttribute,
+	InterleavedBuffer,
+	InterleavedBufferAttribute,
+	TriangleFanDrawMode,
+	TriangleStripDrawMode,
+	TrianglesDrawMode,
+	Vector3,
+} from 'three';
+
+function computeMikkTSpaceTangents( geometry, MikkTSpace, negateSign = true ) {
+
+	if ( ! MikkTSpace || ! MikkTSpace.isReady ) {
+
+		throw new Error( 'BufferGeometryUtils: Initialized MikkTSpace library required.' );
+
+	}
+
+	if ( ! geometry.hasAttribute( 'position' ) || ! geometry.hasAttribute( 'normal' ) || ! geometry.hasAttribute( 'uv' ) ) {
+
+		throw new Error( 'BufferGeometryUtils: Tangents require "position", "normal", and "uv" attributes.' );
+
+	}
+
+	function getAttributeArray( attribute ) {
+
+		if ( attribute.normalized || attribute.isInterleavedBufferAttribute ) {
+
+			const dstArray = new Float32Array( attribute.count * attribute.itemSize );
+
+			for ( let i = 0, j = 0; i < attribute.count; i ++ ) {
+
+				dstArray[ j ++ ] = attribute.getX( i );
+				dstArray[ j ++ ] = attribute.getY( i );
+
+				if ( attribute.itemSize > 2 ) {
+
+					dstArray[ j ++ ] = attribute.getZ( i );
+
+				}
+
+			}
+
+			return dstArray;
+
+		}
+
+		if ( attribute.array instanceof Float32Array ) {
+
+			return attribute.array;
+
+		}
+
+		return new Float32Array( attribute.array );
+
+	}
+
+	// MikkTSpace algorithm requires non-indexed input.
+
+	const _geometry = geometry.index ? geometry.toNonIndexed() : geometry;
+
+	// Compute vertex tangents.
+
+	const tangents = MikkTSpace.generateTangents(
+
+		getAttributeArray( _geometry.attributes.position ),
+		getAttributeArray( _geometry.attributes.normal ),
+		getAttributeArray( _geometry.attributes.uv )
+
+	);
+
+	// Texture coordinate convention of glTF differs from the apparent
+	// default of the MikkTSpace library; .w component must be flipped.
+
+	if ( negateSign ) {
+
+		for ( let i = 3; i < tangents.length; i += 4 ) {
+
+			tangents[ i ] *= - 1;
+
+		}
+
+	}
+
+	//
+
+	_geometry.setAttribute( 'tangent', new BufferAttribute( tangents, 4 ) );
+
+	if ( geometry !== _geometry ) {
+
+		geometry.copy( _geometry );
+
+	}
+
+	return geometry;
+
+}
+
+/**
+ * @param  {Array<BufferGeometry>} geometries
+ * @param  {Boolean} useGroups
+ * @return {BufferGeometry}
+ */
+function mergeGeometries( geometries, useGroups = false ) {
+
+	const isIndexed = geometries[ 0 ].index !== null;
+
+	const attributesUsed = new Set( Object.keys( geometries[ 0 ].attributes ) );
+	const morphAttributesUsed = new Set( Object.keys( geometries[ 0 ].morphAttributes ) );
+
+	const attributes = {};
+	const morphAttributes = {};
+
+	const morphTargetsRelative = geometries[ 0 ].morphTargetsRelative;
+
+	const mergedGeometry = new BufferGeometry();
+
+	let offset = 0;
+
+	for ( let i = 0; i < geometries.length; ++ i ) {
+
+		const geometry = geometries[ i ];
+		let attributesCount = 0;
+
+		// ensure that all geometries are indexed, or none
+
+		if ( isIndexed !== ( geometry.index !== null ) ) {
+
+			console.error( 'THREE.BufferGeometryUtils: .mergeGeometries() failed with geometry at index ' + i + '. All geometries must have compatible attributes; make sure index attribute exists among all geometries, or in none of them.' );
+			return null;
+
+		}
+
+		// gather attributes, exit early if they're different
+
+		for ( const name in geometry.attributes ) {
+
+			if ( ! attributesUsed.has( name ) ) {
+
+				console.error( 'THREE.BufferGeometryUtils: .mergeGeometries() failed with geometry at index ' + i + '. All geometries must have compatible attributes; make sure "' + name + '" attribute exists among all geometries, or in none of them.' );
+				return null;
+
+			}
+
+			if ( attributes[ name ] === undefined ) attributes[ name ] = [];
+
+			attributes[ name ].push( geometry.attributes[ name ] );
+
+			attributesCount ++;
+
+		}
+
+		// ensure geometries have the same number of attributes
+
+		if ( attributesCount !== attributesUsed.size ) {
+
+			console.error( 'THREE.BufferGeometryUtils: .mergeGeometries() failed with geometry at index ' + i + '. Make sure all geometries have the same number of attributes.' );
+			return null;
+
+		}
+
+		// gather morph attributes, exit early if they're different
+
+		if ( morphTargetsRelative !== geometry.morphTargetsRelative ) {
+
+			console.error( 'THREE.BufferGeometryUtils: .mergeGeometries() failed with geometry at index ' + i + '. .morphTargetsRelative must be consistent throughout all geometries.' );
+			return null;
+
+		}
+
+		for ( const name in geometry.morphAttributes ) {
+
+			if ( ! morphAttributesUsed.has( name ) ) {
+
+				console.error( 'THREE.BufferGeometryUtils: .mergeGeometries() failed with geometry at index ' + i + '.  .morphAttributes must be consistent throughout all geometries.' );
+				return null;
+
+			}
+
+			if ( morphAttributes[ name ] === undefined ) morphAttributes[ name ] = [];
+
+			morphAttributes[ name ].push( geometry.morphAttributes[ name ] );
+
+		}
+
+		if ( useGroups ) {
+
+			let count;
+
+			if ( isIndexed ) {
+
+				count = geometry.index.count;
+
+			} else if ( geometry.attributes.position !== undefined ) {
+
+				count = geometry.attributes.position.count;
+
+			} else {
+
+				console.error( 'THREE.BufferGeometryUtils: .mergeGeometries() failed with geometry at index ' + i + '. The geometry must have either an index or a position attribute' );
+				return null;
+
+			}
+
+			mergedGeometry.addGroup( offset, count, i );
+
+			offset += count;
+
+		}
+
+	}
+
+	// merge indices
+
+	if ( isIndexed ) {
+
+		let indexOffset = 0;
+		const mergedIndex = [];
+
+		for ( let i = 0; i < geometries.length; ++ i ) {
+
+			const index = geometries[ i ].index;
+
+			for ( let j = 0; j < index.count; ++ j ) {
+
+				mergedIndex.push( index.getX( j ) + indexOffset );
+
+			}
+
+			indexOffset += geometries[ i ].attributes.position.count;
+
+		}
+
+		mergedGeometry.setIndex( mergedIndex );
+
+	}
+
+	// merge attributes
+
+	for ( const name in attributes ) {
+
+		const mergedAttribute = mergeAttributes( attributes[ name ] );
+
+		if ( ! mergedAttribute ) {
+
+			console.error( 'THREE.BufferGeometryUtils: .mergeGeometries() failed while trying to merge the ' + name + ' attribute.' );
+			return null;
+
+		}
+
+		mergedGeometry.setAttribute( name, mergedAttribute );
+
+	}
+
+	// merge morph attributes
+
+	for ( const name in morphAttributes ) {
+
+		const numMorphTargets = morphAttributes[ name ][ 0 ].length;
+
+		if ( numMorphTargets === 0 ) break;
+
+		mergedGeometry.morphAttributes = mergedGeometry.morphAttributes || {};
+		mergedGeometry.morphAttributes[ name ] = [];
+
+		for ( let i = 0; i < numMorphTargets; ++ i ) {
+
+			const morphAttributesToMerge = [];
+
+			for ( let j = 0; j < morphAttributes[ name ].length; ++ j ) {
+
+				morphAttributesToMerge.push( morphAttributes[ name ][ j ][ i ] );
+
+			}
+
+			const mergedMorphAttribute = mergeAttributes( morphAttributesToMerge );
+
+			if ( ! mergedMorphAttribute ) {
+
+				console.error( 'THREE.BufferGeometryUtils: .mergeGeometries() failed while trying to merge the ' + name + ' morphAttribute.' );
+				return null;
+
+			}
+
+			mergedGeometry.morphAttributes[ name ].push( mergedMorphAttribute );
+
+		}
+
+	}
+
+	return mergedGeometry;
+
+}
+
+/**
+ * @param {Array<BufferAttribute>} attributes
+ * @return {BufferAttribute}
+ */
+function mergeAttributes( attributes ) {
+
+	let TypedArray;
+	let itemSize;
+	let normalized;
+	let gpuType = - 1;
+	let arrayLength = 0;
+
+	for ( let i = 0; i < attributes.length; ++ i ) {
+
+		const attribute = attributes[ i ];
+
+		if ( TypedArray === undefined ) TypedArray = attribute.array.constructor;
+		if ( TypedArray !== attribute.array.constructor ) {
+
+			console.error( 'THREE.BufferGeometryUtils: .mergeAttributes() failed. BufferAttribute.array must be of consistent array types across matching attributes.' );
+			return null;
+
+		}
+
+		if ( itemSize === undefined ) itemSize = attribute.itemSize;
+		if ( itemSize !== attribute.itemSize ) {
+
+			console.error( 'THREE.BufferGeometryUtils: .mergeAttributes() failed. BufferAttribute.itemSize must be consistent across matching attributes.' );
+			return null;
+
+		}
+
+		if ( normalized === undefined ) normalized = attribute.normalized;
+		if ( normalized !== attribute.normalized ) {
+
+			console.error( 'THREE.BufferGeometryUtils: .mergeAttributes() failed. BufferAttribute.normalized must be consistent across matching attributes.' );
+			return null;
+
+		}
+
+		if ( gpuType === - 1 ) gpuType = attribute.gpuType;
+		if ( gpuType !== attribute.gpuType ) {
+
+			console.error( 'THREE.BufferGeometryUtils: .mergeAttributes() failed. BufferAttribute.gpuType must be consistent across matching attributes.' );
+			return null;
+
+		}
+
+		arrayLength += attribute.count * itemSize;
+
+	}
+
+	const array = new TypedArray( arrayLength );
+	const result = new BufferAttribute( array, itemSize, normalized );
+	let offset = 0;
+
+	for ( let i = 0; i < attributes.length; ++ i ) {
+
+		const attribute = attributes[ i ];
+		if ( attribute.isInterleavedBufferAttribute ) {
+
+			const tupleOffset = offset / itemSize;
+			for ( let j = 0, l = attribute.count; j < l; j ++ ) {
+
+				for ( let c = 0; c < itemSize; c ++ ) {
+
+					const value = attribute.getComponent( j, c );
+					result.setComponent( j + tupleOffset, c, value );
+
+				}
+
+			}
+
+		} else {
+
+			array.set( attribute.array, offset );
+
+		}
+
+		offset += attribute.count * itemSize;
+
+	}
+
+	if ( gpuType !== undefined ) {
+
+		result.gpuType = gpuType;
+
+	}
+
+	return result;
+
+}
+
+/**
+ * @param {BufferAttribute}
+ * @return {BufferAttribute}
+ */
+export function deepCloneAttribute( attribute ) {
+
+	if ( attribute.isInstancedInterleavedBufferAttribute || attribute.isInterleavedBufferAttribute ) {
+
+		return deinterleaveAttribute( attribute );
+
+	}
+
+	if ( attribute.isInstancedBufferAttribute ) {
+
+		return new InstancedBufferAttribute().copy( attribute );
+
+	}
+
+	return new BufferAttribute().copy( attribute );
+
+}
+
+/**
+ * @param {Array<BufferAttribute>} attributes
+ * @return {Array<InterleavedBufferAttribute>}
+ */
+function interleaveAttributes( attributes ) {
+
+	// Interleaves the provided attributes into an InterleavedBuffer and returns
+	// a set of InterleavedBufferAttributes for each attribute
+	let TypedArray;
+	let arrayLength = 0;
+	let stride = 0;
+
+	// calculate the length and type of the interleavedBuffer
+	for ( let i = 0, l = attributes.length; i < l; ++ i ) {
+
+		const attribute = attributes[ i ];
+
+		if ( TypedArray === undefined ) TypedArray = attribute.array.constructor;
+		if ( TypedArray !== attribute.array.constructor ) {
+
+			console.error( 'AttributeBuffers of different types cannot be interleaved' );
+			return null;
+
+		}
+
+		arrayLength += attribute.array.length;
+		stride += attribute.itemSize;
+
+	}
+
+	// Create the set of buffer attributes
+	const interleavedBuffer = new InterleavedBuffer( new TypedArray( arrayLength ), stride );
+	let offset = 0;
+	const res = [];
+	const getters = [ 'getX', 'getY', 'getZ', 'getW' ];
+	const setters = [ 'setX', 'setY', 'setZ', 'setW' ];
+
+	for ( let j = 0, l = attributes.length; j < l; j ++ ) {
+
+		const attribute = attributes[ j ];
+		const itemSize = attribute.itemSize;
+		const count = attribute.count;
+		const iba = new InterleavedBufferAttribute( interleavedBuffer, itemSize, offset, attribute.normalized );
+		res.push( iba );
+
+		offset += itemSize;
+
+		// Move the data for each attribute into the new interleavedBuffer
+		// at the appropriate offset
+		for ( let c = 0; c < count; c ++ ) {
+
+			for ( let k = 0; k < itemSize; k ++ ) {
+
+				iba[ setters[ k ] ]( c, attribute[ getters[ k ] ]( c ) );
+
+			}
+
+		}
+
+	}
+
+	return res;
+
+}
+
+// returns a new, non-interleaved version of the provided attribute
+export function deinterleaveAttribute( attribute ) {
+
+	const cons = attribute.data.array.constructor;
+	const count = attribute.count;
+	const itemSize = attribute.itemSize;
+	const normalized = attribute.normalized;
+
+	const array = new cons( count * itemSize );
+	let newAttribute;
+	if ( attribute.isInstancedInterleavedBufferAttribute ) {
+
+		newAttribute = new InstancedBufferAttribute( array, itemSize, normalized, attribute.meshPerAttribute );
+
+	} else {
+
+		newAttribute = new BufferAttribute( array, itemSize, normalized );
+
+	}
+
+	for ( let i = 0; i < count; i ++ ) {
+
+		newAttribute.setX( i, attribute.getX( i ) );
+
+		if ( itemSize >= 2 ) {
+
+			newAttribute.setY( i, attribute.getY( i ) );
+
+		}
+
+		if ( itemSize >= 3 ) {
+
+			newAttribute.setZ( i, attribute.getZ( i ) );
+
+		}
+
+		if ( itemSize >= 4 ) {
+
+			newAttribute.setW( i, attribute.getW( i ) );
+
+		}
+
+	}
+
+	return newAttribute;
+
+}
+
+// deinterleaves all attributes on the geometry
+export function deinterleaveGeometry( geometry ) {
+
+	const attributes = geometry.attributes;
+	const morphTargets = geometry.morphTargets;
+	const attrMap = new Map();
+
+	for ( const key in attributes ) {
+
+		const attr = attributes[ key ];
+		if ( attr.isInterleavedBufferAttribute ) {
+
+			if ( ! attrMap.has( attr ) ) {
+
+				attrMap.set( attr, deinterleaveAttribute( attr ) );
+
+			}
+
+			attributes[ key ] = attrMap.get( attr );
+
+		}
+
+	}
+
+	for ( const key in morphTargets ) {
+
+		const attr = morphTargets[ key ];
+		if ( attr.isInterleavedBufferAttribute ) {
+
+			if ( ! attrMap.has( attr ) ) {
+
+				attrMap.set( attr, deinterleaveAttribute( attr ) );
+
+			}
+
+			morphTargets[ key ] = attrMap.get( attr );
+
+		}
+
+	}
+
+}
+
+/**
+ * @param {BufferGeometry} geometry
+ * @return {number}
+ */
+function estimateBytesUsed( geometry ) {
+
+	// Return the estimated memory used by this geometry in bytes
+	// Calculate using itemSize, count, and BYTES_PER_ELEMENT to account
+	// for InterleavedBufferAttributes.
+	let mem = 0;
+	for ( const name in geometry.attributes ) {
+
+		const attr = geometry.getAttribute( name );
+		mem += attr.count * attr.itemSize * attr.array.BYTES_PER_ELEMENT;
+
+	}
+
+	const indices = geometry.getIndex();
+	mem += indices ? indices.count * indices.itemSize * indices.array.BYTES_PER_ELEMENT : 0;
+	return mem;
+
+}
+
+/**
+ * @param {BufferGeometry} geometry
+ * @param {number} tolerance
+ * @return {BufferGeometry}
+ */
+function mergeVertices( geometry, tolerance = 1e-4 ) {
+
+	tolerance = Math.max( tolerance, Number.EPSILON );
+
+	// Generate an index buffer if the geometry doesn't have one, or optimize it
+	// if it's already available.
+	const hashToIndex = {};
+	const indices = geometry.getIndex();
+	const positions = geometry.getAttribute( 'position' );
+	const vertexCount = indices ? indices.count : positions.count;
+
+	// next value for triangle indices
+	let nextIndex = 0;
+
+	// attributes and new attribute arrays
+	const attributeNames = Object.keys( geometry.attributes );
+	const tmpAttributes = {};
+	const tmpMorphAttributes = {};
+	const newIndices = [];
+	const getters = [ 'getX', 'getY', 'getZ', 'getW' ];
+	const setters = [ 'setX', 'setY', 'setZ', 'setW' ];
+
+	// Initialize the arrays, allocating space conservatively. Extra
+	// space will be trimmed in the last step.
+	for ( let i = 0, l = attributeNames.length; i < l; i ++ ) {
+
+		const name = attributeNames[ i ];
+		const attr = geometry.attributes[ name ];
+
+		tmpAttributes[ name ] = new BufferAttribute(
+			new attr.array.constructor( attr.count * attr.itemSize ),
+			attr.itemSize,
+			attr.normalized
+		);
+
+		const morphAttr = geometry.morphAttributes[ name ];
+		if ( morphAttr ) {
+
+			tmpMorphAttributes[ name ] = new BufferAttribute(
+				new morphAttr.array.constructor( morphAttr.count * morphAttr.itemSize ),
+				morphAttr.itemSize,
+				morphAttr.normalized
+			);
+
+		}
+
+	}
+
+	// convert the error tolerance to an amount of decimal places to truncate to
+	const halfTolerance = tolerance * 0.5;
+	const exponent = Math.log10( 1 / tolerance );
+	const hashMultiplier = Math.pow( 10, exponent );
+	const hashAdditive = halfTolerance * hashMultiplier;
+	for ( let i = 0; i < vertexCount; i ++ ) {
+
+		const index = indices ? indices.getX( i ) : i;
+
+		// Generate a hash for the vertex attributes at the current index 'i'
+		let hash = '';
+		for ( let j = 0, l = attributeNames.length; j < l; j ++ ) {
+
+			const name = attributeNames[ j ];
+			const attribute = geometry.getAttribute( name );
+			const itemSize = attribute.itemSize;
+
+			for ( let k = 0; k < itemSize; k ++ ) {
+
+				// double tilde truncates the decimal value
+				hash += `${ ~ ~ ( attribute[ getters[ k ] ]( index ) * hashMultiplier + hashAdditive ) },`;
+
+			}
+
+		}
+
+		// Add another reference to the vertex if it's already
+		// used by another index
+		if ( hash in hashToIndex ) {
+
+			newIndices.push( hashToIndex[ hash ] );
+
+		} else {
+
+			// copy data to the new index in the temporary attributes
+			for ( let j = 0, l = attributeNames.length; j < l; j ++ ) {
+
+				const name = attributeNames[ j ];
+				const attribute = geometry.getAttribute( name );
+				const morphAttr = geometry.morphAttributes[ name ];
+				const itemSize = attribute.itemSize;
+				const newarray = tmpAttributes[ name ];
+				const newMorphArrays = tmpMorphAttributes[ name ];
+
+				for ( let k = 0; k < itemSize; k ++ ) {
+
+					const getterFunc = getters[ k ];
+					const setterFunc = setters[ k ];
+					newarray[ setterFunc ]( nextIndex, attribute[ getterFunc ]( index ) );
+
+					if ( morphAttr ) {
+
+						for ( let m = 0, ml = morphAttr.length; m < ml; m ++ ) {
+
+							newMorphArrays[ m ][ setterFunc ]( nextIndex, morphAttr[ m ][ getterFunc ]( index ) );
+
+						}
+
+					}
+
+				}
+
+			}
+
+			hashToIndex[ hash ] = nextIndex;
+			newIndices.push( nextIndex );
+			nextIndex ++;
+
+		}
+
+	}
+
+	// generate result BufferGeometry
+	const result = geometry.clone();
+	for ( const name in geometry.attributes ) {
+
+		const tmpAttribute = tmpAttributes[ name ];
+
+		result.setAttribute( name, new BufferAttribute(
+			tmpAttribute.array.slice( 0, nextIndex * tmpAttribute.itemSize ),
+			tmpAttribute.itemSize,
+			tmpAttribute.normalized,
+		) );
+
+		if ( ! ( name in tmpMorphAttributes ) ) continue;
+
+		for ( let j = 0; j < tmpMorphAttributes[ name ].length; j ++ ) {
+
+			const tmpMorphAttribute = tmpMorphAttributes[ name ][ j ];
+
+			result.morphAttributes[ name ][ j ] = new BufferAttribute(
+				tmpMorphAttribute.array.slice( 0, nextIndex * tmpMorphAttribute.itemSize ),
+				tmpMorphAttribute.itemSize,
+				tmpMorphAttribute.normalized,
+			);
+
+		}
+
+	}
+
+	// indices
+
+	result.setIndex( newIndices );
+
+	return result;
+
+}
+
+/**
+ * @param {BufferGeometry} geometry
+ * @param {number} drawMode
+ * @return {BufferGeometry}
+ */
+function toTrianglesDrawMode( geometry, drawMode ) {
+
+	if ( drawMode === TrianglesDrawMode ) {
+
+		console.warn( 'THREE.BufferGeometryUtils.toTrianglesDrawMode(): Geometry already defined as triangles.' );
+		return geometry;
+
+	}
+
+	if ( drawMode === TriangleFanDrawMode || drawMode === TriangleStripDrawMode ) {
+
+		let index = geometry.getIndex();
+
+		// generate index if not present
+
+		if ( index === null ) {
+
+			const indices = [];
+
+			const position = geometry.getAttribute( 'position' );
+
+			if ( position !== undefined ) {
+
+				for ( let i = 0; i < position.count; i ++ ) {
+
+					indices.push( i );
+
+				}
+
+				geometry.setIndex( indices );
+				index = geometry.getIndex();
+
+			} else {
+
+				console.error( 'THREE.BufferGeometryUtils.toTrianglesDrawMode(): Undefined position attribute. Processing not possible.' );
+				return geometry;
+
+			}
+
+		}
+
+		//
+
+		const numberOfTriangles = index.count - 2;
+		const newIndices = [];
+
+		if ( drawMode === TriangleFanDrawMode ) {
+
+			// gl.TRIANGLE_FAN
+
+			for ( let i = 1; i <= numberOfTriangles; i ++ ) {
+
+				newIndices.push( index.getX( 0 ) );
+				newIndices.push( index.getX( i ) );
+				newIndices.push( index.getX( i + 1 ) );
+
+			}
+
+		} else {
+
+			// gl.TRIANGLE_STRIP
+
+			for ( let i = 0; i < numberOfTriangles; i ++ ) {
+
+				if ( i % 2 === 0 ) {
+
+					newIndices.push( index.getX( i ) );
+					newIndices.push( index.getX( i + 1 ) );
+					newIndices.push( index.getX( i + 2 ) );
+
+				} else {
+
+					newIndices.push( index.getX( i + 2 ) );
+					newIndices.push( index.getX( i + 1 ) );
+					newIndices.push( index.getX( i ) );
+
+				}
+
+			}
+
+		}
+
+		if ( ( newIndices.length / 3 ) !== numberOfTriangles ) {
+
+			console.error( 'THREE.BufferGeometryUtils.toTrianglesDrawMode(): Unable to generate correct amount of triangles.' );
+
+		}
+
+		// build final geometry
+
+		const newGeometry = geometry.clone();
+		newGeometry.setIndex( newIndices );
+		newGeometry.clearGroups();
+
+		return newGeometry;
+
+	} else {
+
+		console.error( 'THREE.BufferGeometryUtils.toTrianglesDrawMode(): Unknown draw mode:', drawMode );
+		return geometry;
+
+	}
+
+}
+
+/**
+ * Calculates the morphed attributes of a morphed/skinned BufferGeometry.
+ * Helpful for Raytracing or Decals.
+ * @param {Mesh | Line | Points} object An instance of Mesh, Line or Points.
+ * @return {Object} An Object with original position/normal attributes and morphed ones.
+ */
+function computeMorphedAttributes( object ) {
+
+	const _vA = new Vector3();
+	const _vB = new Vector3();
+	const _vC = new Vector3();
+
+	const _tempA = new Vector3();
+	const _tempB = new Vector3();
+	const _tempC = new Vector3();
+
+	const _morphA = new Vector3();
+	const _morphB = new Vector3();
+	const _morphC = new Vector3();
+
+	function _calculateMorphedAttributeData(
+		object,
+		attribute,
+		morphAttribute,
+		morphTargetsRelative,
+		a,
+		b,
+		c,
+		modifiedAttributeArray
+	) {
+
+		_vA.fromBufferAttribute( attribute, a );
+		_vB.fromBufferAttribute( attribute, b );
+		_vC.fromBufferAttribute( attribute, c );
+
+		const morphInfluences = object.morphTargetInfluences;
+
+		if ( morphAttribute && morphInfluences ) {
+
+			_morphA.set( 0, 0, 0 );
+			_morphB.set( 0, 0, 0 );
+			_morphC.set( 0, 0, 0 );
+
+			for ( let i = 0, il = morphAttribute.length; i < il; i ++ ) {
+
+				const influence = morphInfluences[ i ];
+				const morph = morphAttribute[ i ];
+
+				if ( influence === 0 ) continue;
+
+				_tempA.fromBufferAttribute( morph, a );
+				_tempB.fromBufferAttribute( morph, b );
+				_tempC.fromBufferAttribute( morph, c );
+
+				if ( morphTargetsRelative ) {
+
+					_morphA.addScaledVector( _tempA, influence );
+					_morphB.addScaledVector( _tempB, influence );
+					_morphC.addScaledVector( _tempC, influence );
+
+				} else {
+
+					_morphA.addScaledVector( _tempA.sub( _vA ), influence );
+					_morphB.addScaledVector( _tempB.sub( _vB ), influence );
+					_morphC.addScaledVector( _tempC.sub( _vC ), influence );
+
+				}
+
+			}
+
+			_vA.add( _morphA );
+			_vB.add( _morphB );
+			_vC.add( _morphC );
+
+		}
+
+		if ( object.isSkinnedMesh ) {
+
+			object.applyBoneTransform( a, _vA );
+			object.applyBoneTransform( b, _vB );
+			object.applyBoneTransform( c, _vC );
+
+		}
+
+		modifiedAttributeArray[ a * 3 + 0 ] = _vA.x;
+		modifiedAttributeArray[ a * 3 + 1 ] = _vA.y;
+		modifiedAttributeArray[ a * 3 + 2 ] = _vA.z;
+		modifiedAttributeArray[ b * 3 + 0 ] = _vB.x;
+		modifiedAttributeArray[ b * 3 + 1 ] = _vB.y;
+		modifiedAttributeArray[ b * 3 + 2 ] = _vB.z;
+		modifiedAttributeArray[ c * 3 + 0 ] = _vC.x;
+		modifiedAttributeArray[ c * 3 + 1 ] = _vC.y;
+		modifiedAttributeArray[ c * 3 + 2 ] = _vC.z;
+
+	}
+
+	const geometry = object.geometry;
+	const material = object.material;
+
+	let a, b, c;
+	const index = geometry.index;
+	const positionAttribute = geometry.attributes.position;
+	const morphPosition = geometry.morphAttributes.position;
+	const morphTargetsRelative = geometry.morphTargetsRelative;
+	const normalAttribute = geometry.attributes.normal;
+	const morphNormal = geometry.morphAttributes.position;
+
+	const groups = geometry.groups;
+	const drawRange = geometry.drawRange;
+	let i, j, il, jl;
+	let group;
+	let start, end;
+
+	const modifiedPosition = new Float32Array( positionAttribute.count * positionAttribute.itemSize );
+	const modifiedNormal = new Float32Array( normalAttribute.count * normalAttribute.itemSize );
+
+	if ( index !== null ) {
+
+		// indexed buffer geometry
+
+		if ( Array.isArray( material ) ) {
+
+			for ( i = 0, il = groups.length; i < il; i ++ ) {
+
+				group = groups[ i ];
+
+				start = Math.max( group.start, drawRange.start );
+				end = Math.min( ( group.start + group.count ), ( drawRange.start + drawRange.count ) );
+
+				for ( j = start, jl = end; j < jl; j += 3 ) {
+
+					a = index.getX( j );
+					b = index.getX( j + 1 );
+					c = index.getX( j + 2 );
+
+					_calculateMorphedAttributeData(
+						object,
+						positionAttribute,
+						morphPosition,
+						morphTargetsRelative,
+						a, b, c,
+						modifiedPosition
+					);
+
+					_calculateMorphedAttributeData(
+						object,
+						normalAttribute,
+						morphNormal,
+						morphTargetsRelative,
+						a, b, c,
+						modifiedNormal
+					);
+
+				}
+
+			}
+
+		} else {
+
+			start = Math.max( 0, drawRange.start );
+			end = Math.min( index.count, ( drawRange.start + drawRange.count ) );
+
+			for ( i = start, il = end; i < il; i += 3 ) {
+
+				a = index.getX( i );
+				b = index.getX( i + 1 );
+				c = index.getX( i + 2 );
+
+				_calculateMorphedAttributeData(
+					object,
+					positionAttribute,
+					morphPosition,
+					morphTargetsRelative,
+					a, b, c,
+					modifiedPosition
+				);
+
+				_calculateMorphedAttributeData(
+					object,
+					normalAttribute,
+					morphNormal,
+					morphTargetsRelative,
+					a, b, c,
+					modifiedNormal
+				);
+
+			}
+
+		}
+
+	} else {
+
+		// non-indexed buffer geometry
+
+		if ( Array.isArray( material ) ) {
+
+			for ( i = 0, il = groups.length; i < il; i ++ ) {
+
+				group = groups[ i ];
+
+				start = Math.max( group.start, drawRange.start );
+				end = Math.min( ( group.start + group.count ), ( drawRange.start + drawRange.count ) );
+
+				for ( j = start, jl = end; j < jl; j += 3 ) {
+
+					a = j;
+					b = j + 1;
+					c = j + 2;
+
+					_calculateMorphedAttributeData(
+						object,
+						positionAttribute,
+						morphPosition,
+						morphTargetsRelative,
+						a, b, c,
+						modifiedPosition
+					);
+
+					_calculateMorphedAttributeData(
+						object,
+						normalAttribute,
+						morphNormal,
+						morphTargetsRelative,
+						a, b, c,
+						modifiedNormal
+					);
+
+				}
+
+			}
+
+		} else {
+
+			start = Math.max( 0, drawRange.start );
+			end = Math.min( positionAttribute.count, ( drawRange.start + drawRange.count ) );
+
+			for ( i = start, il = end; i < il; i += 3 ) {
+
+				a = i;
+				b = i + 1;
+				c = i + 2;
+
+				_calculateMorphedAttributeData(
+					object,
+					positionAttribute,
+					morphPosition,
+					morphTargetsRelative,
+					a, b, c,
+					modifiedPosition
+				);
+
+				_calculateMorphedAttributeData(
+					object,
+					normalAttribute,
+					morphNormal,
+					morphTargetsRelative,
+					a, b, c,
+					modifiedNormal
+				);
+
+			}
+
+		}
+
+	}
+
+	const morphedPositionAttribute = new Float32BufferAttribute( modifiedPosition, 3 );
+	const morphedNormalAttribute = new Float32BufferAttribute( modifiedNormal, 3 );
+
+	return {
+
+		positionAttribute: positionAttribute,
+		normalAttribute: normalAttribute,
+		morphedPositionAttribute: morphedPositionAttribute,
+		morphedNormalAttribute: morphedNormalAttribute
+
+	};
+
+}
+
+function mergeGroups( geometry ) {
+
+	if ( geometry.groups.length === 0 ) {
+
+		console.warn( 'THREE.BufferGeometryUtils.mergeGroups(): No groups are defined. Nothing to merge.' );
+		return geometry;
+
+	}
+
+	let groups = geometry.groups;
+
+	// sort groups by material index
+
+	groups = groups.sort( ( a, b ) => {
+
+		if ( a.materialIndex !== b.materialIndex ) return a.materialIndex - b.materialIndex;
+
+		return a.start - b.start;
+
+	} );
+
+	// create index for non-indexed geometries
+
+	if ( geometry.getIndex() === null ) {
+
+		const positionAttribute = geometry.getAttribute( 'position' );
+		const indices = [];
+
+		for ( let i = 0; i < positionAttribute.count; i += 3 ) {
+
+			indices.push( i, i + 1, i + 2 );
+
+		}
+
+		geometry.setIndex( indices );
+
+	}
+
+	// sort index
+
+	const index = geometry.getIndex();
+
+	const newIndices = [];
+
+	for ( let i = 0; i < groups.length; i ++ ) {
+
+		const group = groups[ i ];
+
+		const groupStart = group.start;
+		const groupLength = groupStart + group.count;
+
+		for ( let j = groupStart; j < groupLength; j ++ ) {
+
+			newIndices.push( index.getX( j ) );
+
+		}
+
+	}
+
+	geometry.dispose(); // Required to force buffer recreation
+	geometry.setIndex( newIndices );
+
+	// update groups indices
+
+	let start = 0;
+
+	for ( let i = 0; i < groups.length; i ++ ) {
+
+		const group = groups[ i ];
+
+		group.start = start;
+		start += group.count;
+
+	}
+
+	// merge groups
+
+	let currentGroup = groups[ 0 ];
+
+	geometry.groups = [ currentGroup ];
+
+	for ( let i = 1; i < groups.length; i ++ ) {
+
+		const group = groups[ i ];
+
+		if ( currentGroup.materialIndex === group.materialIndex ) {
+
+			currentGroup.count += group.count;
+
+		} else {
+
+			currentGroup = group;
+			geometry.groups.push( currentGroup );
+
+		}
+
+	}
+
+	return geometry;
+
+}
+
+
+/**
+ * Modifies the supplied geometry if it is non-indexed, otherwise creates a new,
+ * non-indexed geometry. Returns the geometry with smooth normals everywhere except
+ * faces that meet at an angle greater than the crease angle.
+ *
+ * @param {BufferGeometry} geometry
+ * @param {number} [creaseAngle]
+ * @return {BufferGeometry}
+ */
+function toCreasedNormals( geometry, creaseAngle = Math.PI / 3 /* 60 degrees */ ) {
+
+	const creaseDot = Math.cos( creaseAngle );
+	const hashMultiplier = ( 1 + 1e-10 ) * 1e2;
+
+	// reusable vectors
+	const verts = [ new Vector3(), new Vector3(), new Vector3() ];
+	const tempVec1 = new Vector3();
+	const tempVec2 = new Vector3();
+	const tempNorm = new Vector3();
+	const tempNorm2 = new Vector3();
+
+	// hashes a vector
+	function hashVertex( v ) {
+
+		const x = ~ ~ ( v.x * hashMultiplier );
+		const y = ~ ~ ( v.y * hashMultiplier );
+		const z = ~ ~ ( v.z * hashMultiplier );
+		return `${x},${y},${z}`;
+
+	}
+
+	// BufferGeometry.toNonIndexed() warns if the geometry is non-indexed
+	// and returns the original geometry
+	const resultGeometry = geometry.index ? geometry.toNonIndexed() : geometry;
+	const posAttr = resultGeometry.attributes.position;
+	const vertexMap = {};
+
+	// find all the normals shared by commonly located vertices
+	for ( let i = 0, l = posAttr.count / 3; i < l; i ++ ) {
+
+		const i3 = 3 * i;
+		const a = verts[ 0 ].fromBufferAttribute( posAttr, i3 + 0 );
+		const b = verts[ 1 ].fromBufferAttribute( posAttr, i3 + 1 );
+		const c = verts[ 2 ].fromBufferAttribute( posAttr, i3 + 2 );
+
+		tempVec1.subVectors( c, b );
+		tempVec2.subVectors( a, b );
+
+		// add the normal to the map for all vertices
+		const normal = new Vector3().crossVectors( tempVec1, tempVec2 ).normalize();
+		for ( let n = 0; n < 3; n ++ ) {
+
+			const vert = verts[ n ];
+			const hash = hashVertex( vert );
+			if ( ! ( hash in vertexMap ) ) {
+
+				vertexMap[ hash ] = [];
+
+			}
+
+			vertexMap[ hash ].push( normal );
+
+		}
+
+	}
+
+	// average normals from all vertices that share a common location if they are within the
+	// provided crease threshold
+	const normalArray = new Float32Array( posAttr.count * 3 );
+	const normAttr = new BufferAttribute( normalArray, 3, false );
+	for ( let i = 0, l = posAttr.count / 3; i < l; i ++ ) {
+
+		// get the face normal for this vertex
+		const i3 = 3 * i;
+		const a = verts[ 0 ].fromBufferAttribute( posAttr, i3 + 0 );
+		const b = verts[ 1 ].fromBufferAttribute( posAttr, i3 + 1 );
+		const c = verts[ 2 ].fromBufferAttribute( posAttr, i3 + 2 );
+
+		tempVec1.subVectors( c, b );
+		tempVec2.subVectors( a, b );
+
+		tempNorm.crossVectors( tempVec1, tempVec2 ).normalize();
+
+		// average all normals that meet the threshold and set the normal value
+		for ( let n = 0; n < 3; n ++ ) {
+
+			const vert = verts[ n ];
+			const hash = hashVertex( vert );
+			const otherNormals = vertexMap[ hash ];
+			tempNorm2.set( 0, 0, 0 );
+
+			for ( let k = 0, lk = otherNormals.length; k < lk; k ++ ) {
+
+				const otherNorm = otherNormals[ k ];
+				if ( tempNorm.dot( otherNorm ) > creaseDot ) {
+
+					tempNorm2.add( otherNorm );
+
+				}
+
+			}
+
+			tempNorm2.normalize();
+			normAttr.setXYZ( i3 + n, tempNorm2.x, tempNorm2.y, tempNorm2.z );
+
+		}
+
+	}
+
+	resultGeometry.setAttribute( 'normal', normAttr );
+	return resultGeometry;
+
+}
+
+export {
+	computeMikkTSpaceTangents,
+	mergeGeometries,
+	mergeAttributes,
+	interleaveAttributes,
+	estimateBytesUsed,
+	mergeVertices,
+	toTrianglesDrawMode,
+	computeMorphedAttributes,
+	mergeGroups,
+	toCreasedNormals
+};

nicegui/elements/lib/three/modules/GLTFLoader.js

@@ -0,0 +1,4663 @@
+import {
+	AnimationClip,
+	Bone,
+	Box3,
+	BufferAttribute,
+	BufferGeometry,
+	ClampToEdgeWrapping,
+	Color,
+	ColorManagement,
+	DirectionalLight,
+	DoubleSide,
+	FileLoader,
+	FrontSide,
+	Group,
+	ImageBitmapLoader,
+	InstancedMesh,
+	InterleavedBuffer,
+	InterleavedBufferAttribute,
+	Interpolant,
+	InterpolateDiscrete,
+	InterpolateLinear,
+	Line,
+	LineBasicMaterial,
+	LineLoop,
+	LineSegments,
+	LinearFilter,
+	LinearMipmapLinearFilter,
+	LinearMipmapNearestFilter,
+	LinearSRGBColorSpace,
+	Loader,
+	LoaderUtils,
+	Material,
+	MathUtils,
+	Matrix4,
+	Mesh,
+	MeshBasicMaterial,
+	MeshPhysicalMaterial,
+	MeshStandardMaterial,
+	MirroredRepeatWrapping,
+	NearestFilter,
+	NearestMipmapLinearFilter,
+	NearestMipmapNearestFilter,
+	NumberKeyframeTrack,
+	Object3D,
+	OrthographicCamera,
+	PerspectiveCamera,
+	PointLight,
+	Points,
+	PointsMaterial,
+	PropertyBinding,
+	Quaternion,
+	QuaternionKeyframeTrack,
+	RepeatWrapping,
+	Skeleton,
+	SkinnedMesh,
+	Sphere,
+	SpotLight,
+	Texture,
+	TextureLoader,
+	TriangleFanDrawMode,
+	TriangleStripDrawMode,
+	Vector2,
+	Vector3,
+	VectorKeyframeTrack,
+	SRGBColorSpace,
+	InstancedBufferAttribute
+} from 'three';
+import { toTrianglesDrawMode } from 'BufferGeometryUtils';
+
+class GLTFLoader extends Loader {
+
+	constructor( manager ) {
+
+		super( manager );
+
+		this.dracoLoader = null;
+		this.ktx2Loader = null;
+		this.meshoptDecoder = null;
+
+		this.pluginCallbacks = [];
+
+		this.register( function ( parser ) {
+
+			return new GLTFMaterialsClearcoatExtension( parser );
+
+		} );
+
+		this.register( function ( parser ) {
+
+			return new GLTFTextureBasisUExtension( parser );
+
+		} );
+
+		this.register( function ( parser ) {
+
+			return new GLTFTextureWebPExtension( parser );
+
+		} );
+
+		this.register( function ( parser ) {
+
+			return new GLTFTextureAVIFExtension( parser );
+
+		} );
+
+		this.register( function ( parser ) {
+
+			return new GLTFMaterialsSheenExtension( parser );
+
+		} );
+
+		this.register( function ( parser ) {
+
+			return new GLTFMaterialsTransmissionExtension( parser );
+
+		} );
+
+		this.register( function ( parser ) {
+
+			return new GLTFMaterialsVolumeExtension( parser );
+
+		} );
+
+		this.register( function ( parser ) {
+
+			return new GLTFMaterialsIorExtension( parser );
+
+		} );
+
+		this.register( function ( parser ) {
+
+			return new GLTFMaterialsEmissiveStrengthExtension( parser );
+
+		} );
+
+		this.register( function ( parser ) {
+
+			return new GLTFMaterialsSpecularExtension( parser );
+
+		} );
+
+		this.register( function ( parser ) {
+
+			return new GLTFMaterialsIridescenceExtension( parser );
+
+		} );
+
+		this.register( function ( parser ) {
+
+			return new GLTFMaterialsAnisotropyExtension( parser );
+
+		} );
+
+		this.register( function ( parser ) {
+
+			return new GLTFMaterialsBumpExtension( parser );
+
+		} );
+
+		this.register( function ( parser ) {
+
+			return new GLTFLightsExtension( parser );
+
+		} );
+
+		this.register( function ( parser ) {
+
+			return new GLTFMeshoptCompression( parser );
+
+		} );
+
+		this.register( function ( parser ) {
+
+			return new GLTFMeshGpuInstancing( parser );
+
+		} );
+
+	}
+
+	load( url, onLoad, onProgress, onError ) {
+
+		const scope = this;
+
+		let resourcePath;
+
+		if ( this.resourcePath !== '' ) {
+
+			resourcePath = this.resourcePath;
+
+		} else if ( this.path !== '' ) {
+
+			// If a base path is set, resources will be relative paths from that plus the relative path of the gltf file
+			// Example  path = 'https://my-cnd-server.com/', url = 'assets/models/model.gltf'
+			// resourcePath = 'https://my-cnd-server.com/assets/models/'
+			// referenced resource 'model.bin' will be loaded from 'https://my-cnd-server.com/assets/models/model.bin'
+			// referenced resource '../textures/texture.png' will be loaded from 'https://my-cnd-server.com/assets/textures/texture.png'
+			const relativeUrl = LoaderUtils.extractUrlBase( url );
+			resourcePath = LoaderUtils.resolveURL( relativeUrl, this.path );
+
+		} else {
+
+			resourcePath = LoaderUtils.extractUrlBase( url );
+
+		}
+
+		// Tells the LoadingManager to track an extra item, which resolves after
+		// the model is fully loaded. This means the count of items loaded will
+		// be incorrect, but ensures manager.onLoad() does not fire early.
+		this.manager.itemStart( url );
+
+		const _onError = function ( e ) {
+
+			if ( onError ) {
+
+				onError( e );
+
+			} else {
+
+				console.error( e );
+
+			}
+
+			scope.manager.itemError( url );
+			scope.manager.itemEnd( url );
+
+		};
+
+		const loader = new FileLoader( this.manager );
+
+		loader.setPath( this.path );
+		loader.setResponseType( 'arraybuffer' );
+		loader.setRequestHeader( this.requestHeader );
+		loader.setWithCredentials( this.withCredentials );
+
+		loader.load( url, function ( data ) {
+
+			try {
+
+				scope.parse( data, resourcePath, function ( gltf ) {
+
+					onLoad( gltf );
+
+					scope.manager.itemEnd( url );
+
+				}, _onError );
+
+			} catch ( e ) {
+
+				_onError( e );
+
+			}
+
+		}, onProgress, _onError );
+
+	}
+
+	setDRACOLoader( dracoLoader ) {
+
+		this.dracoLoader = dracoLoader;
+		return this;
+
+	}
+
+	setDDSLoader() {
+
+		throw new Error(
+
+			'THREE.GLTFLoader: "MSFT_texture_dds" no longer supported. Please update to "KHR_texture_basisu".'
+
+		);
+
+	}
+
+	setKTX2Loader( ktx2Loader ) {
+
+		this.ktx2Loader = ktx2Loader;
+		return this;
+
+	}
+
+	setMeshoptDecoder( meshoptDecoder ) {
+
+		this.meshoptDecoder = meshoptDecoder;
+		return this;
+
+	}
+
+	register( callback ) {
+
+		if ( this.pluginCallbacks.indexOf( callback ) === - 1 ) {
+
+			this.pluginCallbacks.push( callback );
+
+		}
+
+		return this;
+
+	}
+
+	unregister( callback ) {
+
+		if ( this.pluginCallbacks.indexOf( callback ) !== - 1 ) {
+
+			this.pluginCallbacks.splice( this.pluginCallbacks.indexOf( callback ), 1 );
+
+		}
+
+		return this;
+
+	}
+
+	parse( data, path, onLoad, onError ) {
+
+		let json;
+		const extensions = {};
+		const plugins = {};
+		const textDecoder = new TextDecoder();
+
+		if ( typeof data === 'string' ) {
+
+			json = JSON.parse( data );
+
+		} else if ( data instanceof ArrayBuffer ) {
+
+			const magic = textDecoder.decode( new Uint8Array( data, 0, 4 ) );
+
+			if ( magic === BINARY_EXTENSION_HEADER_MAGIC ) {
+
+				try {
+
+					extensions[ EXTENSIONS.KHR_BINARY_GLTF ] = new GLTFBinaryExtension( data );
+
+				} catch ( error ) {
+
+					if ( onError ) onError( error );
+					return;
+
+				}
+
+				json = JSON.parse( extensions[ EXTENSIONS.KHR_BINARY_GLTF ].content );
+
+			} else {
+
+				json = JSON.parse( textDecoder.decode( data ) );
+
+			}
+
+		} else {
+
+			json = data;
+
+		}
+
+		if ( json.asset === undefined || json.asset.version[ 0 ] < 2 ) {
+
+			if ( onError ) onError( new Error( 'THREE.GLTFLoader: Unsupported asset. glTF versions >=2.0 are supported.' ) );
+			return;
+
+		}
+
+		const parser = new GLTFParser( json, {
+
+			path: path || this.resourcePath || '',
+			crossOrigin: this.crossOrigin,
+			requestHeader: this.requestHeader,
+			manager: this.manager,
+			ktx2Loader: this.ktx2Loader,
+			meshoptDecoder: this.meshoptDecoder
+
+		} );
+
+		parser.fileLoader.setRequestHeader( this.requestHeader );
+
+		for ( let i = 0; i < this.pluginCallbacks.length; i ++ ) {
+
+			const plugin = this.pluginCallbacks[ i ]( parser );
+
+			if ( ! plugin.name ) console.error( 'THREE.GLTFLoader: Invalid plugin found: missing name' );
+
+			plugins[ plugin.name ] = plugin;
+
+			// Workaround to avoid determining as unknown extension
+			// in addUnknownExtensionsToUserData().
+			// Remove this workaround if we move all the existing
+			// extension handlers to plugin system
+			extensions[ plugin.name ] = true;
+
+		}
+
+		if ( json.extensionsUsed ) {
+
+			for ( let i = 0; i < json.extensionsUsed.length; ++ i ) {
+
+				const extensionName = json.extensionsUsed[ i ];
+				const extensionsRequired = json.extensionsRequired || [];
+
+				switch ( extensionName ) {
+
+					case EXTENSIONS.KHR_MATERIALS_UNLIT:
+						extensions[ extensionName ] = new GLTFMaterialsUnlitExtension();
+						break;
+
+					case EXTENSIONS.KHR_DRACO_MESH_COMPRESSION:
+						extensions[ extensionName ] = new GLTFDracoMeshCompressionExtension( json, this.dracoLoader );
+						break;
+
+					case EXTENSIONS.KHR_TEXTURE_TRANSFORM:
+						extensions[ extensionName ] = new GLTFTextureTransformExtension();
+						break;
+
+					case EXTENSIONS.KHR_MESH_QUANTIZATION:
+						extensions[ extensionName ] = new GLTFMeshQuantizationExtension();
+						break;
+
+					default:
+
+						if ( extensionsRequired.indexOf( extensionName ) >= 0 && plugins[ extensionName ] === undefined ) {
+
+							console.warn( 'THREE.GLTFLoader: Unknown extension "' + extensionName + '".' );
+
+						}
+
+				}
+
+			}
+
+		}
+
+		parser.setExtensions( extensions );
+		parser.setPlugins( plugins );
+		parser.parse( onLoad, onError );
+
+	}
+
+	parseAsync( data, path ) {
+
+		const scope = this;
+
+		return new Promise( function ( resolve, reject ) {
+
+			scope.parse( data, path, resolve, reject );
+
+		} );
+
+	}
+
+}
+
+/* GLTFREGISTRY */
+
+function GLTFRegistry() {
+
+	let objects = {};
+
+	return	{
+
+		get: function ( key ) {
+
+			return objects[ key ];
+
+		},
+
+		add: function ( key, object ) {
+
+			objects[ key ] = object;
+
+		},
+
+		remove: function ( key ) {
+
+			delete objects[ key ];
+
+		},
+
+		removeAll: function () {
+
+			objects = {};
+
+		}
+
+	};
+
+}
+
+/*********************************/
+/********** EXTENSIONS ***********/
+/*********************************/
+
+const EXTENSIONS = {
+	KHR_BINARY_GLTF: 'KHR_binary_glTF',
+	KHR_DRACO_MESH_COMPRESSION: 'KHR_draco_mesh_compression',
+	KHR_LIGHTS_PUNCTUAL: 'KHR_lights_punctual',
+	KHR_MATERIALS_CLEARCOAT: 'KHR_materials_clearcoat',
+	KHR_MATERIALS_IOR: 'KHR_materials_ior',
+	KHR_MATERIALS_SHEEN: 'KHR_materials_sheen',
+	KHR_MATERIALS_SPECULAR: 'KHR_materials_specular',
+	KHR_MATERIALS_TRANSMISSION: 'KHR_materials_transmission',
+	KHR_MATERIALS_IRIDESCENCE: 'KHR_materials_iridescence',
+	KHR_MATERIALS_ANISOTROPY: 'KHR_materials_anisotropy',
+	KHR_MATERIALS_UNLIT: 'KHR_materials_unlit',
+	KHR_MATERIALS_VOLUME: 'KHR_materials_volume',
+	KHR_TEXTURE_BASISU: 'KHR_texture_basisu',
+	KHR_TEXTURE_TRANSFORM: 'KHR_texture_transform',
+	KHR_MESH_QUANTIZATION: 'KHR_mesh_quantization',
+	KHR_MATERIALS_EMISSIVE_STRENGTH: 'KHR_materials_emissive_strength',
+	EXT_MATERIALS_BUMP: 'EXT_materials_bump',
+	EXT_TEXTURE_WEBP: 'EXT_texture_webp',
+	EXT_TEXTURE_AVIF: 'EXT_texture_avif',
+	EXT_MESHOPT_COMPRESSION: 'EXT_meshopt_compression',
+	EXT_MESH_GPU_INSTANCING: 'EXT_mesh_gpu_instancing'
+};
+
+/**
+ * Punctual Lights Extension
+ *
+ * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_lights_punctual
+ */
+class GLTFLightsExtension {
+
+	constructor( parser ) {
+
+		this.parser = parser;
+		this.name = EXTENSIONS.KHR_LIGHTS_PUNCTUAL;
+
+		// Object3D instance caches
+		this.cache = { refs: {}, uses: {} };
+
+	}
+
+	_markDefs() {
+
+		const parser = this.parser;
+		const nodeDefs = this.parser.json.nodes || [];
+
+		for ( let nodeIndex = 0, nodeLength = nodeDefs.length; nodeIndex < nodeLength; nodeIndex ++ ) {
+
+			const nodeDef = nodeDefs[ nodeIndex ];
+
+			if ( nodeDef.extensions
+					&& nodeDef.extensions[ this.name ]
+					&& nodeDef.extensions[ this.name ].light !== undefined ) {
+
+				parser._addNodeRef( this.cache, nodeDef.extensions[ this.name ].light );
+
+			}
+
+		}
+
+	}
+
+	_loadLight( lightIndex ) {
+
+		const parser = this.parser;
+		const cacheKey = 'light:' + lightIndex;
+		let dependency = parser.cache.get( cacheKey );
+
+		if ( dependency ) return dependency;
+
+		const json = parser.json;
+		const extensions = ( json.extensions && json.extensions[ this.name ] ) || {};
+		const lightDefs = extensions.lights || [];
+		const lightDef = lightDefs[ lightIndex ];
+		let lightNode;
+
+		const color = new Color( 0xffffff );
+
+		if ( lightDef.color !== undefined ) color.setRGB( lightDef.color[ 0 ], lightDef.color[ 1 ], lightDef.color[ 2 ], LinearSRGBColorSpace );
+
+		const range = lightDef.range !== undefined ? lightDef.range : 0;
+
+		switch ( lightDef.type ) {
+
+			case 'directional':
+				lightNode = new DirectionalLight( color );
+				lightNode.target.position.set( 0, 0, - 1 );
+				lightNode.add( lightNode.target );
+				break;
+
+			case 'point':
+				lightNode = new PointLight( color );
+				lightNode.distance = range;
+				break;
+
+			case 'spot':
+				lightNode = new SpotLight( color );
+				lightNode.distance = range;
+				// Handle spotlight properties.
+				lightDef.spot = lightDef.spot || {};
+				lightDef.spot.innerConeAngle = lightDef.spot.innerConeAngle !== undefined ? lightDef.spot.innerConeAngle : 0;
+				lightDef.spot.outerConeAngle = lightDef.spot.outerConeAngle !== undefined ? lightDef.spot.outerConeAngle : Math.PI / 4.0;
+				lightNode.angle = lightDef.spot.outerConeAngle;
+				lightNode.penumbra = 1.0 - lightDef.spot.innerConeAngle / lightDef.spot.outerConeAngle;
+				lightNode.target.position.set( 0, 0, - 1 );
+				lightNode.add( lightNode.target );
+				break;
+
+			default:
+				throw new Error( 'THREE.GLTFLoader: Unexpected light type: ' + lightDef.type );
+
+		}
+
+		// Some lights (e.g. spot) default to a position other than the origin. Reset the position
+		// here, because node-level parsing will only override position if explicitly specified.
+		lightNode.position.set( 0, 0, 0 );
+
+		lightNode.decay = 2;
+
+		assignExtrasToUserData( lightNode, lightDef );
+
+		if ( lightDef.intensity !== undefined ) lightNode.intensity = lightDef.intensity;
+
+		lightNode.name = parser.createUniqueName( lightDef.name || ( 'light_' + lightIndex ) );
+
+		dependency = Promise.resolve( lightNode );
+
+		parser.cache.add( cacheKey, dependency );
+
+		return dependency;
+
+	}
+
+	getDependency( type, index ) {
+
+		if ( type !== 'light' ) return;
+
+		return this._loadLight( index );
+
+	}
+
+	createNodeAttachment( nodeIndex ) {
+
+		const self = this;
+		const parser = this.parser;
+		const json = parser.json;
+		const nodeDef = json.nodes[ nodeIndex ];
+		const lightDef = ( nodeDef.extensions && nodeDef.extensions[ this.name ] ) || {};
+		const lightIndex = lightDef.light;
+
+		if ( lightIndex === undefined ) return null;
+
+		return this._loadLight( lightIndex ).then( function ( light ) {
+
+			return parser._getNodeRef( self.cache, lightIndex, light );
+
+		} );
+
+	}
+
+}
+
+/**
+ * Unlit Materials Extension
+ *
+ * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_materials_unlit
+ */
+class GLTFMaterialsUnlitExtension {
+
+	constructor() {
+
+		this.name = EXTENSIONS.KHR_MATERIALS_UNLIT;
+
+	}
+
+	getMaterialType() {
+
+		return MeshBasicMaterial;
+
+	}
+
+	extendParams( materialParams, materialDef, parser ) {
+
+		const pending = [];
+
+		materialParams.color = new Color( 1.0, 1.0, 1.0 );
+		materialParams.opacity = 1.0;
+
+		const metallicRoughness = materialDef.pbrMetallicRoughness;
+
+		if ( metallicRoughness ) {
+
+			if ( Array.isArray( metallicRoughness.baseColorFactor ) ) {
+
+				const array = metallicRoughness.baseColorFactor;
+
+				materialParams.color.setRGB( array[ 0 ], array[ 1 ], array[ 2 ], LinearSRGBColorSpace );
+				materialParams.opacity = array[ 3 ];
+
+			}
+
+			if ( metallicRoughness.baseColorTexture !== undefined ) {
+
+				pending.push( parser.assignTexture( materialParams, 'map', metallicRoughness.baseColorTexture, SRGBColorSpace ) );
+
+			}
+
+		}
+
+		return Promise.all( pending );
+
+	}
+
+}
+
+/**
+ * Materials Emissive Strength Extension
+ *
+ * Specification: https://github.com/KhronosGroup/glTF/blob/5768b3ce0ef32bc39cdf1bef10b948586635ead3/extensions/2.0/Khronos/KHR_materials_emissive_strength/README.md
+ */
+class GLTFMaterialsEmissiveStrengthExtension {
+
+	constructor( parser ) {
+
+		this.parser = parser;
+		this.name = EXTENSIONS.KHR_MATERIALS_EMISSIVE_STRENGTH;
+
+	}
+
+	extendMaterialParams( materialIndex, materialParams ) {
+
+		const parser = this.parser;
+		const materialDef = parser.json.materials[ materialIndex ];
+
+		if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) {
+
+			return Promise.resolve();
+
+		}
+
+		const emissiveStrength = materialDef.extensions[ this.name ].emissiveStrength;
+
+		if ( emissiveStrength !== undefined ) {
+
+			materialParams.emissiveIntensity = emissiveStrength;
+
+		}
+
+		return Promise.resolve();
+
+	}
+
+}
+
+/**
+ * Clearcoat Materials Extension
+ *
+ * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_materials_clearcoat
+ */
+class GLTFMaterialsClearcoatExtension {
+
+	constructor( parser ) {
+
+		this.parser = parser;
+		this.name = EXTENSIONS.KHR_MATERIALS_CLEARCOAT;
+
+	}
+
+	getMaterialType( materialIndex ) {
+
+		const parser = this.parser;
+		const materialDef = parser.json.materials[ materialIndex ];
+
+		if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) return null;
+
+		return MeshPhysicalMaterial;
+
+	}
+
+	extendMaterialParams( materialIndex, materialParams ) {
+
+		const parser = this.parser;
+		const materialDef = parser.json.materials[ materialIndex ];
+
+		if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) {
+
+			return Promise.resolve();
+
+		}
+
+		const pending = [];
+
+		const extension = materialDef.extensions[ this.name ];
+
+		if ( extension.clearcoatFactor !== undefined ) {
+
+			materialParams.clearcoat = extension.clearcoatFactor;
+
+		}
+
+		if ( extension.clearcoatTexture !== undefined ) {
+
+			pending.push( parser.assignTexture( materialParams, 'clearcoatMap', extension.clearcoatTexture ) );
+
+		}
+
+		if ( extension.clearcoatRoughnessFactor !== undefined ) {
+
+			materialParams.clearcoatRoughness = extension.clearcoatRoughnessFactor;
+
+		}
+
+		if ( extension.clearcoatRoughnessTexture !== undefined ) {
+
+			pending.push( parser.assignTexture( materialParams, 'clearcoatRoughnessMap', extension.clearcoatRoughnessTexture ) );
+
+		}
+
+		if ( extension.clearcoatNormalTexture !== undefined ) {
+
+			pending.push( parser.assignTexture( materialParams, 'clearcoatNormalMap', extension.clearcoatNormalTexture ) );
+
+			if ( extension.clearcoatNormalTexture.scale !== undefined ) {
+
+				const scale = extension.clearcoatNormalTexture.scale;
+
+				materialParams.clearcoatNormalScale = new Vector2( scale, scale );
+
+			}
+
+		}
+
+		return Promise.all( pending );
+
+	}
+
+}
+
+/**
+ * Iridescence Materials Extension
+ *
+ * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_materials_iridescence
+ */
+class GLTFMaterialsIridescenceExtension {
+
+	constructor( parser ) {
+
+		this.parser = parser;
+		this.name = EXTENSIONS.KHR_MATERIALS_IRIDESCENCE;
+
+	}
+
+	getMaterialType( materialIndex ) {
+
+		const parser = this.parser;
+		const materialDef = parser.json.materials[ materialIndex ];
+
+		if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) return null;
+
+		return MeshPhysicalMaterial;
+
+	}
+
+	extendMaterialParams( materialIndex, materialParams ) {
+
+		const parser = this.parser;
+		const materialDef = parser.json.materials[ materialIndex ];
+
+		if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) {
+
+			return Promise.resolve();
+
+		}
+
+		const pending = [];
+
+		const extension = materialDef.extensions[ this.name ];
+
+		if ( extension.iridescenceFactor !== undefined ) {
+
+			materialParams.iridescence = extension.iridescenceFactor;
+
+		}
+
+		if ( extension.iridescenceTexture !== undefined ) {
+
+			pending.push( parser.assignTexture( materialParams, 'iridescenceMap', extension.iridescenceTexture ) );
+
+		}
+
+		if ( extension.iridescenceIor !== undefined ) {
+
+			materialParams.iridescenceIOR = extension.iridescenceIor;
+
+		}
+
+		if ( materialParams.iridescenceThicknessRange === undefined ) {
+
+			materialParams.iridescenceThicknessRange = [ 100, 400 ];
+
+		}
+
+		if ( extension.iridescenceThicknessMinimum !== undefined ) {
+
+			materialParams.iridescenceThicknessRange[ 0 ] = extension.iridescenceThicknessMinimum;
+
+		}
+
+		if ( extension.iridescenceThicknessMaximum !== undefined ) {
+
+			materialParams.iridescenceThicknessRange[ 1 ] = extension.iridescenceThicknessMaximum;
+
+		}
+
+		if ( extension.iridescenceThicknessTexture !== undefined ) {
+
+			pending.push( parser.assignTexture( materialParams, 'iridescenceThicknessMap', extension.iridescenceThicknessTexture ) );
+
+		}
+
+		return Promise.all( pending );
+
+	}
+
+}
+
+/**
+ * Sheen Materials Extension
+ *
+ * Specification: https://github.com/KhronosGroup/glTF/tree/main/extensions/2.0/Khronos/KHR_materials_sheen
+ */
+class GLTFMaterialsSheenExtension {
+
+	constructor( parser ) {
+
+		this.parser = parser;
+		this.name = EXTENSIONS.KHR_MATERIALS_SHEEN;
+
+	}
+
+	getMaterialType( materialIndex ) {
+
+		const parser = this.parser;
+		const materialDef = parser.json.materials[ materialIndex ];
+
+		if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) return null;
+
+		return MeshPhysicalMaterial;
+
+	}
+
+	extendMaterialParams( materialIndex, materialParams ) {
+
+		const parser = this.parser;
+		const materialDef = parser.json.materials[ materialIndex ];
+
+		if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) {
+
+			return Promise.resolve();
+
+		}
+
+		const pending = [];
+
+		materialParams.sheenColor = new Color( 0, 0, 0 );
+		materialParams.sheenRoughness = 0;
+		materialParams.sheen = 1;
+
+		const extension = materialDef.extensions[ this.name ];
+
+		if ( extension.sheenColorFactor !== undefined ) {
+
+			const colorFactor = extension.sheenColorFactor;
+			materialParams.sheenColor.setRGB( colorFactor[ 0 ], colorFactor[ 1 ], colorFactor[ 2 ], LinearSRGBColorSpace );
+
+		}
+
+		if ( extension.sheenRoughnessFactor !== undefined ) {
+
+			materialParams.sheenRoughness = extension.sheenRoughnessFactor;
+
+		}
+
+		if ( extension.sheenColorTexture !== undefined ) {
+
+			pending.push( parser.assignTexture( materialParams, 'sheenColorMap', extension.sheenColorTexture, SRGBColorSpace ) );
+
+		}
+
+		if ( extension.sheenRoughnessTexture !== undefined ) {
+
+			pending.push( parser.assignTexture( materialParams, 'sheenRoughnessMap', extension.sheenRoughnessTexture ) );
+
+		}
+
+		return Promise.all( pending );
+
+	}
+
+}
+
+/**
+ * Transmission Materials Extension
+ *
+ * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_materials_transmission
+ * Draft: https://github.com/KhronosGroup/glTF/pull/1698
+ */
+class GLTFMaterialsTransmissionExtension {
+
+	constructor( parser ) {
+
+		this.parser = parser;
+		this.name = EXTENSIONS.KHR_MATERIALS_TRANSMISSION;
+
+	}
+
+	getMaterialType( materialIndex ) {
+
+		const parser = this.parser;
+		const materialDef = parser.json.materials[ materialIndex ];
+
+		if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) return null;
+
+		return MeshPhysicalMaterial;
+
+	}
+
+	extendMaterialParams( materialIndex, materialParams ) {
+
+		const parser = this.parser;
+		const materialDef = parser.json.materials[ materialIndex ];
+
+		if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) {
+
+			return Promise.resolve();
+
+		}
+
+		const pending = [];
+
+		const extension = materialDef.extensions[ this.name ];
+
+		if ( extension.transmissionFactor !== undefined ) {
+
+			materialParams.transmission = extension.transmissionFactor;
+
+		}
+
+		if ( extension.transmissionTexture !== undefined ) {
+
+			pending.push( parser.assignTexture( materialParams, 'transmissionMap', extension.transmissionTexture ) );
+
+		}
+
+		return Promise.all( pending );
+
+	}
+
+}
+
+/**
+ * Materials Volume Extension
+ *
+ * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_materials_volume
+ */
+class GLTFMaterialsVolumeExtension {
+
+	constructor( parser ) {
+
+		this.parser = parser;
+		this.name = EXTENSIONS.KHR_MATERIALS_VOLUME;
+
+	}
+
+	getMaterialType( materialIndex ) {
+
+		const parser = this.parser;
+		const materialDef = parser.json.materials[ materialIndex ];
+
+		if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) return null;
+
+		return MeshPhysicalMaterial;
+
+	}
+
+	extendMaterialParams( materialIndex, materialParams ) {
+
+		const parser = this.parser;
+		const materialDef = parser.json.materials[ materialIndex ];
+
+		if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) {
+
+			return Promise.resolve();
+
+		}
+
+		const pending = [];
+
+		const extension = materialDef.extensions[ this.name ];
+
+		materialParams.thickness = extension.thicknessFactor !== undefined ? extension.thicknessFactor : 0;
+
+		if ( extension.thicknessTexture !== undefined ) {
+
+			pending.push( parser.assignTexture( materialParams, 'thicknessMap', extension.thicknessTexture ) );
+
+		}
+
+		materialParams.attenuationDistance = extension.attenuationDistance || Infinity;
+
+		const colorArray = extension.attenuationColor || [ 1, 1, 1 ];
+		materialParams.attenuationColor = new Color().setRGB( colorArray[ 0 ], colorArray[ 1 ], colorArray[ 2 ], LinearSRGBColorSpace );
+
+		return Promise.all( pending );
+
+	}
+
+}
+
+/**
+ * Materials ior Extension
+ *
+ * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_materials_ior
+ */
+class GLTFMaterialsIorExtension {
+
+	constructor( parser ) {
+
+		this.parser = parser;
+		this.name = EXTENSIONS.KHR_MATERIALS_IOR;
+
+	}
+
+	getMaterialType( materialIndex ) {
+
+		const parser = this.parser;
+		const materialDef = parser.json.materials[ materialIndex ];
+
+		if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) return null;
+
+		return MeshPhysicalMaterial;
+
+	}
+
+	extendMaterialParams( materialIndex, materialParams ) {
+
+		const parser = this.parser;
+		const materialDef = parser.json.materials[ materialIndex ];
+
+		if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) {
+
+			return Promise.resolve();
+
+		}
+
+		const extension = materialDef.extensions[ this.name ];
+
+		materialParams.ior = extension.ior !== undefined ? extension.ior : 1.5;
+
+		return Promise.resolve();
+
+	}
+
+}
+
+/**
+ * Materials specular Extension
+ *
+ * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_materials_specular
+ */
+class GLTFMaterialsSpecularExtension {
+
+	constructor( parser ) {
+
+		this.parser = parser;
+		this.name = EXTENSIONS.KHR_MATERIALS_SPECULAR;
+
+	}
+
+	getMaterialType( materialIndex ) {
+
+		const parser = this.parser;
+		const materialDef = parser.json.materials[ materialIndex ];
+
+		if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) return null;
+
+		return MeshPhysicalMaterial;
+
+	}
+
+	extendMaterialParams( materialIndex, materialParams ) {
+
+		const parser = this.parser;
+		const materialDef = parser.json.materials[ materialIndex ];
+
+		if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) {
+
+			return Promise.resolve();
+
+		}
+
+		const pending = [];
+
+		const extension = materialDef.extensions[ this.name ];
+
+		materialParams.specularIntensity = extension.specularFactor !== undefined ? extension.specularFactor : 1.0;
+
+		if ( extension.specularTexture !== undefined ) {
+
+			pending.push( parser.assignTexture( materialParams, 'specularIntensityMap', extension.specularTexture ) );
+
+		}
+
+		const colorArray = extension.specularColorFactor || [ 1, 1, 1 ];
+		materialParams.specularColor = new Color().setRGB( colorArray[ 0 ], colorArray[ 1 ], colorArray[ 2 ], LinearSRGBColorSpace );
+
+		if ( extension.specularColorTexture !== undefined ) {
+
+			pending.push( parser.assignTexture( materialParams, 'specularColorMap', extension.specularColorTexture, SRGBColorSpace ) );
+
+		}
+
+		return Promise.all( pending );
+
+	}
+
+}
+
+
+/**
+ * Materials bump Extension
+ *
+ * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/EXT_materials_bump
+ */
+class GLTFMaterialsBumpExtension {
+
+	constructor( parser ) {
+
+		this.parser = parser;
+		this.name = EXTENSIONS.EXT_MATERIALS_BUMP;
+
+	}
+
+	getMaterialType( materialIndex ) {
+
+		const parser = this.parser;
+		const materialDef = parser.json.materials[ materialIndex ];
+
+		if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) return null;
+
+		return MeshPhysicalMaterial;
+
+	}
+
+	extendMaterialParams( materialIndex, materialParams ) {
+
+		const parser = this.parser;
+		const materialDef = parser.json.materials[ materialIndex ];
+
+		if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) {
+
+			return Promise.resolve();
+
+		}
+
+		const pending = [];
+
+		const extension = materialDef.extensions[ this.name ];
+
+		materialParams.bumpScale = extension.bumpFactor !== undefined ? extension.bumpFactor : 1.0;
+
+		if ( extension.bumpTexture !== undefined ) {
+
+			pending.push( parser.assignTexture( materialParams, 'bumpMap', extension.bumpTexture ) );
+
+		}
+
+		return Promise.all( pending );
+
+	}
+
+}
+
+/**
+ * Materials anisotropy Extension
+ *
+ * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_materials_anisotropy
+ */
+class GLTFMaterialsAnisotropyExtension {
+
+	constructor( parser ) {
+
+		this.parser = parser;
+		this.name = EXTENSIONS.KHR_MATERIALS_ANISOTROPY;
+
+	}
+
+	getMaterialType( materialIndex ) {
+
+		const parser = this.parser;
+		const materialDef = parser.json.materials[ materialIndex ];
+
+		if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) return null;
+
+		return MeshPhysicalMaterial;
+
+	}
+
+	extendMaterialParams( materialIndex, materialParams ) {
+
+		const parser = this.parser;
+		const materialDef = parser.json.materials[ materialIndex ];
+
+		if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) {
+
+			return Promise.resolve();
+
+		}
+
+		const pending = [];
+
+		const extension = materialDef.extensions[ this.name ];
+
+		if ( extension.anisotropyStrength !== undefined ) {
+
+			materialParams.anisotropy = extension.anisotropyStrength;
+
+		}
+
+		if ( extension.anisotropyRotation !== undefined ) {
+
+			materialParams.anisotropyRotation = extension.anisotropyRotation;
+
+		}
+
+		if ( extension.anisotropyTexture !== undefined ) {
+
+			pending.push( parser.assignTexture( materialParams, 'anisotropyMap', extension.anisotropyTexture ) );
+
+		}
+
+		return Promise.all( pending );
+
+	}
+
+}
+
+/**
+ * BasisU Texture Extension
+ *
+ * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_texture_basisu
+ */
+class GLTFTextureBasisUExtension {
+
+	constructor( parser ) {
+
+		this.parser = parser;
+		this.name = EXTENSIONS.KHR_TEXTURE_BASISU;
+
+	}
+
+	loadTexture( textureIndex ) {
+
+		const parser = this.parser;
+		const json = parser.json;
+
+		const textureDef = json.textures[ textureIndex ];
+
+		if ( ! textureDef.extensions || ! textureDef.extensions[ this.name ] ) {
+
+			return null;
+
+		}
+
+		const extension = textureDef.extensions[ this.name ];
+		const loader = parser.options.ktx2Loader;
+
+		if ( ! loader ) {
+
+			if ( json.extensionsRequired && json.extensionsRequired.indexOf( this.name ) >= 0 ) {
+
+				throw new Error( 'THREE.GLTFLoader: setKTX2Loader must be called before loading KTX2 textures' );
+
+			} else {
+
+				// Assumes that the extension is optional and that a fallback texture is present
+				return null;
+
+			}
+
+		}
+
+		return parser.loadTextureImage( textureIndex, extension.source, loader );
+
+	}
+
+}
+
+/**
+ * WebP Texture Extension
+ *
+ * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Vendor/EXT_texture_webp
+ */
+class GLTFTextureWebPExtension {
+
+	constructor( parser ) {
+
+		this.parser = parser;
+		this.name = EXTENSIONS.EXT_TEXTURE_WEBP;
+		this.isSupported = null;
+
+	}
+
+	loadTexture( textureIndex ) {
+
+		const name = this.name;
+		const parser = this.parser;
+		const json = parser.json;
+
+		const textureDef = json.textures[ textureIndex ];
+
+		if ( ! textureDef.extensions || ! textureDef.extensions[ name ] ) {
+
+			return null;
+
+		}
+
+		const extension = textureDef.extensions[ name ];
+		const source = json.images[ extension.source ];
+
+		let loader = parser.textureLoader;
+		if ( source.uri ) {
+
+			const handler = parser.options.manager.getHandler( source.uri );
+			if ( handler !== null ) loader = handler;
+
+		}
+
+		return this.detectSupport().then( function ( isSupported ) {
+
+			if ( isSupported ) return parser.loadTextureImage( textureIndex, extension.source, loader );
+
+			if ( json.extensionsRequired && json.extensionsRequired.indexOf( name ) >= 0 ) {
+
+				throw new Error( 'THREE.GLTFLoader: WebP required by asset but unsupported.' );
+
+			}
+
+			// Fall back to PNG or JPEG.
+			return parser.loadTexture( textureIndex );
+
+		} );
+
+	}
+
+	detectSupport() {
+
+		if ( ! this.isSupported ) {
+
+			this.isSupported = new Promise( function ( resolve ) {
+
+				const image = new Image();
+
+				// Lossy test image. Support for lossy images doesn't guarantee support for all
+				// WebP images, unfortunately.
+				image.src = 'data:image/webp;base64,UklGRiIAAABXRUJQVlA4IBYAAAAwAQCdASoBAAEADsD+JaQAA3AAAAAA';
+
+				image.onload = image.onerror = function () {
+
+					resolve( image.height === 1 );
+
+				};
+
+			} );
+
+		}
+
+		return this.isSupported;
+
+	}
+
+}
+
+/**
+ * AVIF Texture Extension
+ *
+ * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Vendor/EXT_texture_avif
+ */
+class GLTFTextureAVIFExtension {
+
+	constructor( parser ) {
+
+		this.parser = parser;
+		this.name = EXTENSIONS.EXT_TEXTURE_AVIF;
+		this.isSupported = null;
+
+	}
+
+	loadTexture( textureIndex ) {
+
+		const name = this.name;
+		const parser = this.parser;
+		const json = parser.json;
+
+		const textureDef = json.textures[ textureIndex ];
+
+		if ( ! textureDef.extensions || ! textureDef.extensions[ name ] ) {
+
+			return null;
+
+		}
+
+		const extension = textureDef.extensions[ name ];
+		const source = json.images[ extension.source ];
+
+		let loader = parser.textureLoader;
+		if ( source.uri ) {
+
+			const handler = parser.options.manager.getHandler( source.uri );
+			if ( handler !== null ) loader = handler;
+
+		}
+
+		return this.detectSupport().then( function ( isSupported ) {
+
+			if ( isSupported ) return parser.loadTextureImage( textureIndex, extension.source, loader );
+
+			if ( json.extensionsRequired && json.extensionsRequired.indexOf( name ) >= 0 ) {
+
+				throw new Error( 'THREE.GLTFLoader: AVIF required by asset but unsupported.' );
+
+			}
+
+			// Fall back to PNG or JPEG.
+			return parser.loadTexture( textureIndex );
+
+		} );
+
+	}
+
+	detectSupport() {
+
+		if ( ! this.isSupported ) {
+
+			this.isSupported = new Promise( function ( resolve ) {
+
+				const image = new Image();
+
+				// Lossy test image.
+				image.src = 'data:image/avif;base64,AAAAIGZ0eXBhdmlmAAAAAGF2aWZtaWYxbWlhZk1BMUIAAADybWV0YQAAAAAAAAAoaGRscgAAAAAAAAAAcGljdAAAAAAAAAAAAAAAAGxpYmF2aWYAAAAADnBpdG0AAAAAAAEAAAAeaWxvYwAAAABEAAABAAEAAAABAAABGgAAABcAAAAoaWluZgAAAAAAAQAAABppbmZlAgAAAAABAABhdjAxQ29sb3IAAAAAamlwcnAAAABLaXBjbwAAABRpc3BlAAAAAAAAAAEAAAABAAAAEHBpeGkAAAAAAwgICAAAAAxhdjFDgQAMAAAAABNjb2xybmNseAACAAIABoAAAAAXaXBtYQAAAAAAAAABAAEEAQKDBAAAAB9tZGF0EgAKCBgABogQEDQgMgkQAAAAB8dSLfI=';
+				image.onload = image.onerror = function () {
+
+					resolve( image.height === 1 );
+
+				};
+
+			} );
+
+		}
+
+		return this.isSupported;
+
+	}
+
+}
+
+/**
+ * meshopt BufferView Compression Extension
+ *
+ * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Vendor/EXT_meshopt_compression
+ */
+class GLTFMeshoptCompression {
+
+	constructor( parser ) {
+
+		this.name = EXTENSIONS.EXT_MESHOPT_COMPRESSION;
+		this.parser = parser;
+
+	}
+
+	loadBufferView( index ) {
+
+		const json = this.parser.json;
+		const bufferView = json.bufferViews[ index ];
+
+		if ( bufferView.extensions && bufferView.extensions[ this.name ] ) {
+
+			const extensionDef = bufferView.extensions[ this.name ];
+
+			const buffer = this.parser.getDependency( 'buffer', extensionDef.buffer );
+			const decoder = this.parser.options.meshoptDecoder;
+
+			if ( ! decoder || ! decoder.supported ) {
+
+				if ( json.extensionsRequired && json.extensionsRequired.indexOf( this.name ) >= 0 ) {
+
+					throw new Error( 'THREE.GLTFLoader: setMeshoptDecoder must be called before loading compressed files' );
+
+				} else {
+
+					// Assumes that the extension is optional and that fallback buffer data is present
+					return null;
+
+				}
+
+			}
+
+			return buffer.then( function ( res ) {
+
+				const byteOffset = extensionDef.byteOffset || 0;
+				const byteLength = extensionDef.byteLength || 0;
+
+				const count = extensionDef.count;
+				const stride = extensionDef.byteStride;
+
+				const source = new Uint8Array( res, byteOffset, byteLength );
+
+				if ( decoder.decodeGltfBufferAsync ) {
+
+					return decoder.decodeGltfBufferAsync( count, stride, source, extensionDef.mode, extensionDef.filter ).then( function ( res ) {
+
+						return res.buffer;
+
+					} );
+
+				} else {
+
+					// Support for MeshoptDecoder 0.18 or earlier, without decodeGltfBufferAsync
+					return decoder.ready.then( function () {
+
+						const result = new ArrayBuffer( count * stride );
+						decoder.decodeGltfBuffer( new Uint8Array( result ), count, stride, source, extensionDef.mode, extensionDef.filter );
+						return result;
+
+					} );
+
+				}
+
+			} );
+
+		} else {
+
+			return null;
+
+		}
+
+	}
+
+}
+
+/**
+ * GPU Instancing Extension
+ *
+ * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Vendor/EXT_mesh_gpu_instancing
+ *
+ */
+class GLTFMeshGpuInstancing {
+
+	constructor( parser ) {
+
+		this.name = EXTENSIONS.EXT_MESH_GPU_INSTANCING;
+		this.parser = parser;
+
+	}
+
+	createNodeMesh( nodeIndex ) {
+
+		const json = this.parser.json;
+		const nodeDef = json.nodes[ nodeIndex ];
+
+		if ( ! nodeDef.extensions || ! nodeDef.extensions[ this.name ] ||
+			nodeDef.mesh === undefined ) {
+
+			return null;
+
+		}
+
+		const meshDef = json.meshes[ nodeDef.mesh ];
+
+		// No Points or Lines + Instancing support yet
+
+		for ( const primitive of meshDef.primitives ) {
+
+			if ( primitive.mode !== WEBGL_CONSTANTS.TRIANGLES &&
+				 primitive.mode !== WEBGL_CONSTANTS.TRIANGLE_STRIP &&
+				 primitive.mode !== WEBGL_CONSTANTS.TRIANGLE_FAN &&
+				 primitive.mode !== undefined ) {
+
+				return null;
+
+			}
+
+		}
+
+		const extensionDef = nodeDef.extensions[ this.name ];
+		const attributesDef = extensionDef.attributes;
+
+		// @TODO: Can we support InstancedMesh + SkinnedMesh?
+
+		const pending = [];
+		const attributes = {};
+
+		for ( const key in attributesDef ) {
+
+			pending.push( this.parser.getDependency( 'accessor', attributesDef[ key ] ).then( accessor => {
+
+				attributes[ key ] = accessor;
+				return attributes[ key ];
+
+			} ) );
+
+		}
+
+		if ( pending.length < 1 ) {
+
+			return null;
+
+		}
+
+		pending.push( this.parser.createNodeMesh( nodeIndex ) );
+
+		return Promise.all( pending ).then( results => {
+
+			const nodeObject = results.pop();
+			const meshes = nodeObject.isGroup ? nodeObject.children : [ nodeObject ];
+			const count = results[ 0 ].count; // All attribute counts should be same
+			const instancedMeshes = [];
+
+			for ( const mesh of meshes ) {
+
+				// Temporal variables
+				const m = new Matrix4();
+				const p = new Vector3();
+				const q = new Quaternion();
+				const s = new Vector3( 1, 1, 1 );
+
+				const instancedMesh = new InstancedMesh( mesh.geometry, mesh.material, count );
+
+				for ( let i = 0; i < count; i ++ ) {
+
+					if ( attributes.TRANSLATION ) {
+
+						p.fromBufferAttribute( attributes.TRANSLATION, i );
+
+					}
+
+					if ( attributes.ROTATION ) {
+
+						q.fromBufferAttribute( attributes.ROTATION, i );
+
+					}
+
+					if ( attributes.SCALE ) {
+
+						s.fromBufferAttribute( attributes.SCALE, i );
+
+					}
+
+					instancedMesh.setMatrixAt( i, m.compose( p, q, s ) );
+
+				}
+
+				// Add instance attributes to the geometry, excluding TRS.
+				for ( const attributeName in attributes ) {
+
+					if ( attributeName === '_COLOR_0' ) {
+
+						const attr = attributes[ attributeName ];
+						instancedMesh.instanceColor = new InstancedBufferAttribute( attr.array, attr.itemSize, attr.normalized );
+
+					} else if ( attributeName !== 'TRANSLATION' &&
+						 attributeName !== 'ROTATION' &&
+						 attributeName !== 'SCALE' ) {
+
+						mesh.geometry.setAttribute( attributeName, attributes[ attributeName ] );
+
+					}
+
+				}
+
+				// Just in case
+				Object3D.prototype.copy.call( instancedMesh, mesh );
+
+				this.parser.assignFinalMaterial( instancedMesh );
+
+				instancedMeshes.push( instancedMesh );
+
+			}
+
+			if ( nodeObject.isGroup ) {
+
+				nodeObject.clear();
+
+				nodeObject.add( ... instancedMeshes );
+
+				return nodeObject;
+
+			}
+
+			return instancedMeshes[ 0 ];
+
+		} );
+
+	}
+
+}
+
+/* BINARY EXTENSION */
+const BINARY_EXTENSION_HEADER_MAGIC = 'glTF';
+const BINARY_EXTENSION_HEADER_LENGTH = 12;
+const BINARY_EXTENSION_CHUNK_TYPES = { JSON: 0x4E4F534A, BIN: 0x004E4942 };
+
+class GLTFBinaryExtension {
+
+	constructor( data ) {
+
+		this.name = EXTENSIONS.KHR_BINARY_GLTF;
+		this.content = null;
+		this.body = null;
+
+		const headerView = new DataView( data, 0, BINARY_EXTENSION_HEADER_LENGTH );
+		const textDecoder = new TextDecoder();
+
+		this.header = {
+			magic: textDecoder.decode( new Uint8Array( data.slice( 0, 4 ) ) ),
+			version: headerView.getUint32( 4, true ),
+			length: headerView.getUint32( 8, true )
+		};
+
+		if ( this.header.magic !== BINARY_EXTENSION_HEADER_MAGIC ) {
+
+			throw new Error( 'THREE.GLTFLoader: Unsupported glTF-Binary header.' );
+
+		} else if ( this.header.version < 2.0 ) {
+
+			throw new Error( 'THREE.GLTFLoader: Legacy binary file detected.' );
+
+		}
+
+		const chunkContentsLength = this.header.length - BINARY_EXTENSION_HEADER_LENGTH;
+		const chunkView = new DataView( data, BINARY_EXTENSION_HEADER_LENGTH );
+		let chunkIndex = 0;
+
+		while ( chunkIndex < chunkContentsLength ) {
+
+			const chunkLength = chunkView.getUint32( chunkIndex, true );
+			chunkIndex += 4;
+
+			const chunkType = chunkView.getUint32( chunkIndex, true );
+			chunkIndex += 4;
+
+			if ( chunkType === BINARY_EXTENSION_CHUNK_TYPES.JSON ) {
+
+				const contentArray = new Uint8Array( data, BINARY_EXTENSION_HEADER_LENGTH + chunkIndex, chunkLength );
+				this.content = textDecoder.decode( contentArray );
+
+			} else if ( chunkType === BINARY_EXTENSION_CHUNK_TYPES.BIN ) {
+
+				const byteOffset = BINARY_EXTENSION_HEADER_LENGTH + chunkIndex;
+				this.body = data.slice( byteOffset, byteOffset + chunkLength );
+
+			}
+
+			// Clients must ignore chunks with unknown types.
+
+			chunkIndex += chunkLength;
+
+		}
+
+		if ( this.content === null ) {
+
+			throw new Error( 'THREE.GLTFLoader: JSON content not found.' );
+
+		}
+
+	}
+
+}
+
+/**
+ * DRACO Mesh Compression Extension
+ *
+ * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_draco_mesh_compression
+ */
+class GLTFDracoMeshCompressionExtension {
+
+	constructor( json, dracoLoader ) {
+
+		if ( ! dracoLoader ) {
+
+			throw new Error( 'THREE.GLTFLoader: No DRACOLoader instance provided.' );
+
+		}
+
+		this.name = EXTENSIONS.KHR_DRACO_MESH_COMPRESSION;
+		this.json = json;
+		this.dracoLoader = dracoLoader;
+		this.dracoLoader.preload();
+
+	}
+
+	decodePrimitive( primitive, parser ) {
+
+		const json = this.json;
+		const dracoLoader = this.dracoLoader;
+		const bufferViewIndex = primitive.extensions[ this.name ].bufferView;
+		const gltfAttributeMap = primitive.extensions[ this.name ].attributes;
+		const threeAttributeMap = {};
+		const attributeNormalizedMap = {};
+		const attributeTypeMap = {};
+
+		for ( const attributeName in gltfAttributeMap ) {
+
+			const threeAttributeName = ATTRIBUTES[ attributeName ] || attributeName.toLowerCase();
+
+			threeAttributeMap[ threeAttributeName ] = gltfAttributeMap[ attributeName ];
+
+		}
+
+		for ( const attributeName in primitive.attributes ) {
+
+			const threeAttributeName = ATTRIBUTES[ attributeName ] || attributeName.toLowerCase();
+
+			if ( gltfAttributeMap[ attributeName ] !== undefined ) {
+
+				const accessorDef = json.accessors[ primitive.attributes[ attributeName ] ];
+				const componentType = WEBGL_COMPONENT_TYPES[ accessorDef.componentType ];
+
+				attributeTypeMap[ threeAttributeName ] = componentType.name;
+				attributeNormalizedMap[ threeAttributeName ] = accessorDef.normalized === true;
+
+			}
+
+		}
+
+		return parser.getDependency( 'bufferView', bufferViewIndex ).then( function ( bufferView ) {
+
+			return new Promise( function ( resolve, reject ) {
+
+				dracoLoader.decodeDracoFile( bufferView, function ( geometry ) {
+
+					for ( const attributeName in geometry.attributes ) {
+
+						const attribute = geometry.attributes[ attributeName ];
+						const normalized = attributeNormalizedMap[ attributeName ];
+
+						if ( normalized !== undefined ) attribute.normalized = normalized;
+
+					}
+
+					resolve( geometry );
+
+				}, threeAttributeMap, attributeTypeMap, LinearSRGBColorSpace, reject );
+
+			} );
+
+		} );
+
+	}
+
+}
+
+/**
+ * Texture Transform Extension
+ *
+ * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_texture_transform
+ */
+class GLTFTextureTransformExtension {
+
+	constructor() {
+
+		this.name = EXTENSIONS.KHR_TEXTURE_TRANSFORM;
+
+	}
+
+	extendTexture( texture, transform ) {
+
+		if ( ( transform.texCoord === undefined || transform.texCoord === texture.channel )
+			&& transform.offset === undefined
+			&& transform.rotation === undefined
+			&& transform.scale === undefined ) {
+
+			// See https://github.com/mrdoob/three.js/issues/21819.
+			return texture;
+
+		}
+
+		texture = texture.clone();
+
+		if ( transform.texCoord !== undefined ) {
+
+			texture.channel = transform.texCoord;
+
+		}
+
+		if ( transform.offset !== undefined ) {
+
+			texture.offset.fromArray( transform.offset );
+
+		}
+
+		if ( transform.rotation !== undefined ) {
+
+			texture.rotation = transform.rotation;
+
+		}
+
+		if ( transform.scale !== undefined ) {
+
+			texture.repeat.fromArray( transform.scale );
+
+		}
+
+		texture.needsUpdate = true;
+
+		return texture;
+
+	}
+
+}
+
+/**
+ * Mesh Quantization Extension
+ *
+ * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_mesh_quantization
+ */
+class GLTFMeshQuantizationExtension {
+
+	constructor() {
+
+		this.name = EXTENSIONS.KHR_MESH_QUANTIZATION;
+
+	}
+
+}
+
+/*********************************/
+/********** INTERPOLATION ********/
+/*********************************/
+
+// Spline Interpolation
+// Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#appendix-c-spline-interpolation
+class GLTFCubicSplineInterpolant extends Interpolant {
+
+	constructor( parameterPositions, sampleValues, sampleSize, resultBuffer ) {
+
+		super( parameterPositions, sampleValues, sampleSize, resultBuffer );
+
+	}
+
+	copySampleValue_( index ) {
+
+		// Copies a sample value to the result buffer. See description of glTF
+		// CUBICSPLINE values layout in interpolate_() function below.
+
+		const result = this.resultBuffer,
+			values = this.sampleValues,
+			valueSize = this.valueSize,
+			offset = index * valueSize * 3 + valueSize;
+
+		for ( let i = 0; i !== valueSize; i ++ ) {
+
+			result[ i ] = values[ offset + i ];
+
+		}
+
+		return result;
+
+	}
+
+	interpolate_( i1, t0, t, t1 ) {
+
+		const result = this.resultBuffer;
+		const values = this.sampleValues;
+		const stride = this.valueSize;
+
+		const stride2 = stride * 2;
+		const stride3 = stride * 3;
+
+		const td = t1 - t0;
+
+		const p = ( t - t0 ) / td;
+		const pp = p * p;
+		const ppp = pp * p;
+
+		const offset1 = i1 * stride3;
+		const offset0 = offset1 - stride3;
+
+		const s2 = - 2 * ppp + 3 * pp;
+		const s3 = ppp - pp;
+		const s0 = 1 - s2;
+		const s1 = s3 - pp + p;
+
+		// Layout of keyframe output values for CUBICSPLINE animations:
+		//   [ inTangent_1, splineVertex_1, outTangent_1, inTangent_2, splineVertex_2, ... ]
+		for ( let i = 0; i !== stride; i ++ ) {
+
+			const p0 = values[ offset0 + i + stride ]; // splineVertex_k
+			const m0 = values[ offset0 + i + stride2 ] * td; // outTangent_k * (t_k+1 - t_k)
+			const p1 = values[ offset1 + i + stride ]; // splineVertex_k+1
+			const m1 = values[ offset1 + i ] * td; // inTangent_k+1 * (t_k+1 - t_k)
+
+			result[ i ] = s0 * p0 + s1 * m0 + s2 * p1 + s3 * m1;
+
+		}
+
+		return result;
+
+	}
+
+}
+
+const _q = new Quaternion();
+
+class GLTFCubicSplineQuaternionInterpolant extends GLTFCubicSplineInterpolant {
+
+	interpolate_( i1, t0, t, t1 ) {
+
+		const result = super.interpolate_( i1, t0, t, t1 );
+
+		_q.fromArray( result ).normalize().toArray( result );
+
+		return result;
+
+	}
+
+}
+
+
+/*********************************/
+/********** INTERNALS ************/
+/*********************************/
+
+/* CONSTANTS */
+
+const WEBGL_CONSTANTS = {
+	FLOAT: 5126,
+	//FLOAT_MAT2: 35674,
+	FLOAT_MAT3: 35675,
+	FLOAT_MAT4: 35676,
+	FLOAT_VEC2: 35664,
+	FLOAT_VEC3: 35665,
+	FLOAT_VEC4: 35666,
+	LINEAR: 9729,
+	REPEAT: 10497,
+	SAMPLER_2D: 35678,
+	POINTS: 0,
+	LINES: 1,
+	LINE_LOOP: 2,
+	LINE_STRIP: 3,
+	TRIANGLES: 4,
+	TRIANGLE_STRIP: 5,
+	TRIANGLE_FAN: 6,
+	UNSIGNED_BYTE: 5121,
+	UNSIGNED_SHORT: 5123
+};
+
+const WEBGL_COMPONENT_TYPES = {
+	5120: Int8Array,
+	5121: Uint8Array,
+	5122: Int16Array,
+	5123: Uint16Array,
+	5125: Uint32Array,
+	5126: Float32Array
+};
+
+const WEBGL_FILTERS = {
+	9728: NearestFilter,
+	9729: LinearFilter,
+	9984: NearestMipmapNearestFilter,
+	9985: LinearMipmapNearestFilter,
+	9986: NearestMipmapLinearFilter,
+	9987: LinearMipmapLinearFilter
+};
+
+const WEBGL_WRAPPINGS = {
+	33071: ClampToEdgeWrapping,
+	33648: MirroredRepeatWrapping,
+	10497: RepeatWrapping
+};
+
+const WEBGL_TYPE_SIZES = {
+	'SCALAR': 1,
+	'VEC2': 2,
+	'VEC3': 3,
+	'VEC4': 4,
+	'MAT2': 4,
+	'MAT3': 9,
+	'MAT4': 16
+};
+
+const ATTRIBUTES = {
+	POSITION: 'position',
+	NORMAL: 'normal',
+	TANGENT: 'tangent',
+	TEXCOORD_0: 'uv',
+	TEXCOORD_1: 'uv1',
+	TEXCOORD_2: 'uv2',
+	TEXCOORD_3: 'uv3',
+	COLOR_0: 'color',
+	WEIGHTS_0: 'skinWeight',
+	JOINTS_0: 'skinIndex',
+};
+
+const PATH_PROPERTIES = {
+	scale: 'scale',
+	translation: 'position',
+	rotation: 'quaternion',
+	weights: 'morphTargetInfluences'
+};
+
+const INTERPOLATION = {
+	CUBICSPLINE: undefined, // We use a custom interpolant (GLTFCubicSplineInterpolation) for CUBICSPLINE tracks. Each
+		                        // keyframe track will be initialized with a default interpolation type, then modified.
+	LINEAR: InterpolateLinear,
+	STEP: InterpolateDiscrete
+};
+
+const ALPHA_MODES = {
+	OPAQUE: 'OPAQUE',
+	MASK: 'MASK',
+	BLEND: 'BLEND'
+};
+
+/**
+ * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#default-material
+ */
+function createDefaultMaterial( cache ) {
+
+	if ( cache[ 'DefaultMaterial' ] === undefined ) {
+
+		cache[ 'DefaultMaterial' ] = new MeshStandardMaterial( {
+			color: 0xFFFFFF,
+			emissive: 0x000000,
+			metalness: 1,
+			roughness: 1,
+			transparent: false,
+			depthTest: true,
+			side: FrontSide
+		} );
+
+	}
+
+	return cache[ 'DefaultMaterial' ];
+
+}
+
+function addUnknownExtensionsToUserData( knownExtensions, object, objectDef ) {
+
+	// Add unknown glTF extensions to an object's userData.
+
+	for ( const name in objectDef.extensions ) {
+
+		if ( knownExtensions[ name ] === undefined ) {
+
+			object.userData.gltfExtensions = object.userData.gltfExtensions || {};
+			object.userData.gltfExtensions[ name ] = objectDef.extensions[ name ];
+
+		}
+
+	}
+
+}
+
+/**
+ * @param {Object3D|Material|BufferGeometry} object
+ * @param {GLTF.definition} gltfDef
+ */
+function assignExtrasToUserData( object, gltfDef ) {
+
+	if ( gltfDef.extras !== undefined ) {
+
+		if ( typeof gltfDef.extras === 'object' ) {
+
+			Object.assign( object.userData, gltfDef.extras );
+
+		} else {
+
+			console.warn( 'THREE.GLTFLoader: Ignoring primitive type .extras, ' + gltfDef.extras );
+
+		}
+
+	}
+
+}
+
+/**
+ * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#morph-targets
+ *
+ * @param {BufferGeometry} geometry
+ * @param {Array<GLTF.Target>} targets
+ * @param {GLTFParser} parser
+ * @return {Promise<BufferGeometry>}
+ */
+function addMorphTargets( geometry, targets, parser ) {
+
+	let hasMorphPosition = false;
+	let hasMorphNormal = false;
+	let hasMorphColor = false;
+
+	for ( let i = 0, il = targets.length; i < il; i ++ ) {
+
+		const target = targets[ i ];
+
+		if ( target.POSITION !== undefined ) hasMorphPosition = true;
+		if ( target.NORMAL !== undefined ) hasMorphNormal = true;
+		if ( target.COLOR_0 !== undefined ) hasMorphColor = true;
+
+		if ( hasMorphPosition && hasMorphNormal && hasMorphColor ) break;
+
+	}
+
+	if ( ! hasMorphPosition && ! hasMorphNormal && ! hasMorphColor ) return Promise.resolve( geometry );
+
+	const pendingPositionAccessors = [];
+	const pendingNormalAccessors = [];
+	const pendingColorAccessors = [];
+
+	for ( let i = 0, il = targets.length; i < il; i ++ ) {
+
+		const target = targets[ i ];
+
+		if ( hasMorphPosition ) {
+
+			const pendingAccessor = target.POSITION !== undefined
+				? parser.getDependency( 'accessor', target.POSITION )
+				: geometry.attributes.position;
+
+			pendingPositionAccessors.push( pendingAccessor );
+
+		}
+
+		if ( hasMorphNormal ) {
+
+			const pendingAccessor = target.NORMAL !== undefined
+				? parser.getDependency( 'accessor', target.NORMAL )
+				: geometry.attributes.normal;
+
+			pendingNormalAccessors.push( pendingAccessor );
+
+		}
+
+		if ( hasMorphColor ) {
+
+			const pendingAccessor = target.COLOR_0 !== undefined
+				? parser.getDependency( 'accessor', target.COLOR_0 )
+				: geometry.attributes.color;
+
+			pendingColorAccessors.push( pendingAccessor );
+
+		}
+
+	}
+
+	return Promise.all( [
+		Promise.all( pendingPositionAccessors ),
+		Promise.all( pendingNormalAccessors ),
+		Promise.all( pendingColorAccessors )
+	] ).then( function ( accessors ) {
+
+		const morphPositions = accessors[ 0 ];
+		const morphNormals = accessors[ 1 ];
+		const morphColors = accessors[ 2 ];
+
+		if ( hasMorphPosition ) geometry.morphAttributes.position = morphPositions;
+		if ( hasMorphNormal ) geometry.morphAttributes.normal = morphNormals;
+		if ( hasMorphColor ) geometry.morphAttributes.color = morphColors;
+		geometry.morphTargetsRelative = true;
+
+		return geometry;
+
+	} );
+
+}
+
+/**
+ * @param {Mesh} mesh
+ * @param {GLTF.Mesh} meshDef
+ */
+function updateMorphTargets( mesh, meshDef ) {
+
+	mesh.updateMorphTargets();
+
+	if ( meshDef.weights !== undefined ) {
+
+		for ( let i = 0, il = meshDef.weights.length; i < il; i ++ ) {
+
+			mesh.morphTargetInfluences[ i ] = meshDef.weights[ i ];
+
+		}
+
+	}
+
+	// .extras has user-defined data, so check that .extras.targetNames is an array.
+	if ( meshDef.extras && Array.isArray( meshDef.extras.targetNames ) ) {
+
+		const targetNames = meshDef.extras.targetNames;
+
+		if ( mesh.morphTargetInfluences.length === targetNames.length ) {
+
+			mesh.morphTargetDictionary = {};
+
+			for ( let i = 0, il = targetNames.length; i < il; i ++ ) {
+
+				mesh.morphTargetDictionary[ targetNames[ i ] ] = i;
+
+			}
+
+		} else {
+
+			console.warn( 'THREE.GLTFLoader: Invalid extras.targetNames length. Ignoring names.' );
+
+		}
+
+	}
+
+}
+
+function createPrimitiveKey( primitiveDef ) {
+
+	let geometryKey;
+
+	const dracoExtension = primitiveDef.extensions && primitiveDef.extensions[ EXTENSIONS.KHR_DRACO_MESH_COMPRESSION ];
+
+	if ( dracoExtension ) {
+
+		geometryKey = 'draco:' + dracoExtension.bufferView
+				+ ':' + dracoExtension.indices
+				+ ':' + createAttributesKey( dracoExtension.attributes );
+
+	} else {
+
+		geometryKey = primitiveDef.indices + ':' + createAttributesKey( primitiveDef.attributes ) + ':' + primitiveDef.mode;
+
+	}
+
+	if ( primitiveDef.targets !== undefined ) {
+
+		for ( let i = 0, il = primitiveDef.targets.length; i < il; i ++ ) {
+
+			geometryKey += ':' + createAttributesKey( primitiveDef.targets[ i ] );
+
+		}
+
+	}
+
+	return geometryKey;
+
+}
+
+function createAttributesKey( attributes ) {
+
+	let attributesKey = '';
+
+	const keys = Object.keys( attributes ).sort();
+
+	for ( let i = 0, il = keys.length; i < il; i ++ ) {
+
+		attributesKey += keys[ i ] + ':' + attributes[ keys[ i ] ] + ';';
+
+	}
+
+	return attributesKey;
+
+}
+
+function getNormalizedComponentScale( constructor ) {
+
+	// Reference:
+	// https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_mesh_quantization#encoding-quantized-data
+
+	switch ( constructor ) {
+
+		case Int8Array:
+			return 1 / 127;
+
+		case Uint8Array:
+			return 1 / 255;
+
+		case Int16Array:
+			return 1 / 32767;
+
+		case Uint16Array:
+			return 1 / 65535;
+
+		default:
+			throw new Error( 'THREE.GLTFLoader: Unsupported normalized accessor component type.' );
+
+	}
+
+}
+
+function getImageURIMimeType( uri ) {
+
+	if ( uri.search( /\.jpe?g($|\?)/i ) > 0 || uri.search( /^data\:image\/jpeg/ ) === 0 ) return 'image/jpeg';
+	if ( uri.search( /\.webp($|\?)/i ) > 0 || uri.search( /^data\:image\/webp/ ) === 0 ) return 'image/webp';
+
+	return 'image/png';
+
+}
+
+const _identityMatrix = new Matrix4();
+
+/* GLTF PARSER */
+
+class GLTFParser {
+
+	constructor( json = {}, options = {} ) {
+
+		this.json = json;
+		this.extensions = {};
+		this.plugins = {};
+		this.options = options;
+
+		// loader object cache
+		this.cache = new GLTFRegistry();
+
+		// associations between Three.js objects and glTF elements
+		this.associations = new Map();
+
+		// BufferGeometry caching
+		this.primitiveCache = {};
+
+		// Node cache
+		this.nodeCache = {};
+
+		// Object3D instance caches
+		this.meshCache = { refs: {}, uses: {} };
+		this.cameraCache = { refs: {}, uses: {} };
+		this.lightCache = { refs: {}, uses: {} };
+
+		this.sourceCache = {};
+		this.textureCache = {};
+
+		// Track node names, to ensure no duplicates
+		this.nodeNamesUsed = {};
+
+		// Use an ImageBitmapLoader if imageBitmaps are supported. Moves much of the
+		// expensive work of uploading a texture to the GPU off the main thread.
+
+		let isSafari = false;
+		let isFirefox = false;
+		let firefoxVersion = - 1;
+
+		if ( typeof navigator !== 'undefined' ) {
+
+			isSafari = /^((?!chrome|android).)*safari/i.test( navigator.userAgent ) === true;
+			isFirefox = navigator.userAgent.indexOf( 'Firefox' ) > - 1;
+			firefoxVersion = isFirefox ? navigator.userAgent.match( /Firefox\/([0-9]+)\./ )[ 1 ] : - 1;
+
+		}
+
+		if ( typeof createImageBitmap === 'undefined' || isSafari || ( isFirefox && firefoxVersion < 98 ) ) {
+
+			this.textureLoader = new TextureLoader( this.options.manager );
+
+		} else {
+
+			this.textureLoader = new ImageBitmapLoader( this.options.manager );
+
+		}
+
+		this.textureLoader.setCrossOrigin( this.options.crossOrigin );
+		this.textureLoader.setRequestHeader( this.options.requestHeader );
+
+		this.fileLoader = new FileLoader( this.options.manager );
+		this.fileLoader.setResponseType( 'arraybuffer' );
+
+		if ( this.options.crossOrigin === 'use-credentials' ) {
+
+			this.fileLoader.setWithCredentials( true );
+
+		}
+
+	}
+
+	setExtensions( extensions ) {
+
+		this.extensions = extensions;
+
+	}
+
+	setPlugins( plugins ) {
+
+		this.plugins = plugins;
+
+	}
+
+	parse( onLoad, onError ) {
+
+		const parser = this;
+		const json = this.json;
+		const extensions = this.extensions;
+
+		// Clear the loader cache
+		this.cache.removeAll();
+		this.nodeCache = {};
+
+		// Mark the special nodes/meshes in json for efficient parse
+		this._invokeAll( function ( ext ) {
+
+			return ext._markDefs && ext._markDefs();
+
+		} );
+
+		Promise.all( this._invokeAll( function ( ext ) {
+
+			return ext.beforeRoot && ext.beforeRoot();
+
+		} ) ).then( function () {
+
+			return Promise.all( [
+
+				parser.getDependencies( 'scene' ),
+				parser.getDependencies( 'animation' ),
+				parser.getDependencies( 'camera' ),
+
+			] );
+
+		} ).then( function ( dependencies ) {
+
+			const result = {
+				scene: dependencies[ 0 ][ json.scene || 0 ],
+				scenes: dependencies[ 0 ],
+				animations: dependencies[ 1 ],
+				cameras: dependencies[ 2 ],
+				asset: json.asset,
+				parser: parser,
+				userData: {}
+			};
+
+			addUnknownExtensionsToUserData( extensions, result, json );
+
+			assignExtrasToUserData( result, json );
+
+			return Promise.all( parser._invokeAll( function ( ext ) {
+
+				return ext.afterRoot && ext.afterRoot( result );
+
+			} ) ).then( function () {
+
+				onLoad( result );
+
+			} );
+
+		} ).catch( onError );
+
+	}
+
+	/**
+	 * Marks the special nodes/meshes in json for efficient parse.
+	 */
+	_markDefs() {
+
+		const nodeDefs = this.json.nodes || [];
+		const skinDefs = this.json.skins || [];
+		const meshDefs = this.json.meshes || [];
+
+		// Nothing in the node definition indicates whether it is a Bone or an
+		// Object3D. Use the skins' joint references to mark bones.
+		for ( let skinIndex = 0, skinLength = skinDefs.length; skinIndex < skinLength; skinIndex ++ ) {
+
+			const joints = skinDefs[ skinIndex ].joints;
+
+			for ( let i = 0, il = joints.length; i < il; i ++ ) {
+
+				nodeDefs[ joints[ i ] ].isBone = true;
+
+			}
+
+		}
+
+		// Iterate over all nodes, marking references to shared resources,
+		// as well as skeleton joints.
+		for ( let nodeIndex = 0, nodeLength = nodeDefs.length; nodeIndex < nodeLength; nodeIndex ++ ) {
+
+			const nodeDef = nodeDefs[ nodeIndex ];
+
+			if ( nodeDef.mesh !== undefined ) {
+
+				this._addNodeRef( this.meshCache, nodeDef.mesh );
+
+				// Nothing in the mesh definition indicates whether it is
+				// a SkinnedMesh or Mesh. Use the node's mesh reference
+				// to mark SkinnedMesh if node has skin.
+				if ( nodeDef.skin !== undefined ) {
+
+					meshDefs[ nodeDef.mesh ].isSkinnedMesh = true;
+
+				}
+
+			}
+
+			if ( nodeDef.camera !== undefined ) {
+
+				this._addNodeRef( this.cameraCache, nodeDef.camera );
+
+			}
+
+		}
+
+	}
+
+	/**
+	 * Counts references to shared node / Object3D resources. These resources
+	 * can be reused, or "instantiated", at multiple nodes in the scene
+	 * hierarchy. Mesh, Camera, and Light instances are instantiated and must
+	 * be marked. Non-scenegraph resources (like Materials, Geometries, and
+	 * Textures) can be reused directly and are not marked here.
+	 *
+	 * Example: CesiumMilkTruck sample model reuses "Wheel" meshes.
+	 */
+	_addNodeRef( cache, index ) {
+
+		if ( index === undefined ) return;
+
+		if ( cache.refs[ index ] === undefined ) {
+
+			cache.refs[ index ] = cache.uses[ index ] = 0;
+
+		}
+
+		cache.refs[ index ] ++;
+
+	}
+
+	/** Returns a reference to a shared resource, cloning it if necessary. */
+	_getNodeRef( cache, index, object ) {
+
+		if ( cache.refs[ index ] <= 1 ) return object;
+
+		const ref = object.clone();
+
+		// Propagates mappings to the cloned object, prevents mappings on the
+		// original object from being lost.
+		const updateMappings = ( original, clone ) => {
+
+			const mappings = this.associations.get( original );
+			if ( mappings != null ) {
+
+				this.associations.set( clone, mappings );
+
+			}
+
+			for ( const [ i, child ] of original.children.entries() ) {
+
+				updateMappings( child, clone.children[ i ] );
+
+			}
+
+		};
+
+		updateMappings( object, ref );
+
+		ref.name += '_instance_' + ( cache.uses[ index ] ++ );
+
+		return ref;
+
+	}
+
+	_invokeOne( func ) {
+
+		const extensions = Object.values( this.plugins );
+		extensions.push( this );
+
+		for ( let i = 0; i < extensions.length; i ++ ) {
+
+			const result = func( extensions[ i ] );
+
+			if ( result ) return result;
+
+		}
+
+		return null;
+
+	}
+
+	_invokeAll( func ) {
+
+		const extensions = Object.values( this.plugins );
+		extensions.unshift( this );
+
+		const pending = [];
+
+		for ( let i = 0; i < extensions.length; i ++ ) {
+
+			const result = func( extensions[ i ] );
+
+			if ( result ) pending.push( result );
+
+		}
+
+		return pending;
+
+	}
+
+	/**
+	 * Requests the specified dependency asynchronously, with caching.
+	 * @param {string} type
+	 * @param {number} index
+	 * @return {Promise<Object3D|Material|THREE.Texture|AnimationClip|ArrayBuffer|Object>}
+	 */
+	getDependency( type, index ) {
+
+		const cacheKey = type + ':' + index;
+		let dependency = this.cache.get( cacheKey );
+
+		if ( ! dependency ) {
+
+			switch ( type ) {
+
+				case 'scene':
+					dependency = this.loadScene( index );
+					break;
+
+				case 'node':
+					dependency = this._invokeOne( function ( ext ) {
+
+						return ext.loadNode && ext.loadNode( index );
+
+					} );
+					break;
+
+				case 'mesh':
+					dependency = this._invokeOne( function ( ext ) {
+
+						return ext.loadMesh && ext.loadMesh( index );
+
+					} );
+					break;
+
+				case 'accessor':
+					dependency = this.loadAccessor( index );
+					break;
+
+				case 'bufferView':
+					dependency = this._invokeOne( function ( ext ) {
+
+						return ext.loadBufferView && ext.loadBufferView( index );
+
+					} );
+					break;
+
+				case 'buffer':
+					dependency = this.loadBuffer( index );
+					break;
+
+				case 'material':
+					dependency = this._invokeOne( function ( ext ) {
+
+						return ext.loadMaterial && ext.loadMaterial( index );
+
+					} );
+					break;
+
+				case 'texture':
+					dependency = this._invokeOne( function ( ext ) {
+
+						return ext.loadTexture && ext.loadTexture( index );
+
+					} );
+					break;
+
+				case 'skin':
+					dependency = this.loadSkin( index );
+					break;
+
+				case 'animation':
+					dependency = this._invokeOne( function ( ext ) {
+
+						return ext.loadAnimation && ext.loadAnimation( index );
+
+					} );
+					break;
+
+				case 'camera':
+					dependency = this.loadCamera( index );
+					break;
+
+				default:
+					dependency = this._invokeOne( function ( ext ) {
+
+						return ext != this && ext.getDependency && ext.getDependency( type, index );
+
+					} );
+
+					if ( ! dependency ) {
+
+						throw new Error( 'Unknown type: ' + type );
+
+					}
+
+					break;
+
+			}
+
+			this.cache.add( cacheKey, dependency );
+
+		}
+
+		return dependency;
+
+	}
+
+	/**
+	 * Requests all dependencies of the specified type asynchronously, with caching.
+	 * @param {string} type
+	 * @return {Promise<Array<Object>>}
+	 */
+	getDependencies( type ) {
+
+		let dependencies = this.cache.get( type );
+
+		if ( ! dependencies ) {
+
+			const parser = this;
+			const defs = this.json[ type + ( type === 'mesh' ? 'es' : 's' ) ] || [];
+
+			dependencies = Promise.all( defs.map( function ( def, index ) {
+
+				return parser.getDependency( type, index );
+
+			} ) );
+
+			this.cache.add( type, dependencies );
+
+		}
+
+		return dependencies;
+
+	}
+
+	/**
+	 * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#buffers-and-buffer-views
+	 * @param {number} bufferIndex
+	 * @return {Promise<ArrayBuffer>}
+	 */
+	loadBuffer( bufferIndex ) {
+
+		const bufferDef = this.json.buffers[ bufferIndex ];
+		const loader = this.fileLoader;
+
+		if ( bufferDef.type && bufferDef.type !== 'arraybuffer' ) {
+
+			throw new Error( 'THREE.GLTFLoader: ' + bufferDef.type + ' buffer type is not supported.' );
+
+		}
+
+		// If present, GLB container is required to be the first buffer.
+		if ( bufferDef.uri === undefined && bufferIndex === 0 ) {
+
+			return Promise.resolve( this.extensions[ EXTENSIONS.KHR_BINARY_GLTF ].body );
+
+		}
+
+		const options = this.options;
+
+		return new Promise( function ( resolve, reject ) {
+
+			loader.load( LoaderUtils.resolveURL( bufferDef.uri, options.path ), resolve, undefined, function () {
+
+				reject( new Error( 'THREE.GLTFLoader: Failed to load buffer "' + bufferDef.uri + '".' ) );
+
+			} );
+
+		} );
+
+	}
+
+	/**
+	 * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#buffers-and-buffer-views
+	 * @param {number} bufferViewIndex
+	 * @return {Promise<ArrayBuffer>}
+	 */
+	loadBufferView( bufferViewIndex ) {
+
+		const bufferViewDef = this.json.bufferViews[ bufferViewIndex ];
+
+		return this.getDependency( 'buffer', bufferViewDef.buffer ).then( function ( buffer ) {
+
+			const byteLength = bufferViewDef.byteLength || 0;
+			const byteOffset = bufferViewDef.byteOffset || 0;
+			return buffer.slice( byteOffset, byteOffset + byteLength );
+
+		} );
+
+	}
+
+	/**
+	 * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#accessors
+	 * @param {number} accessorIndex
+	 * @return {Promise<BufferAttribute|InterleavedBufferAttribute>}
+	 */
+	loadAccessor( accessorIndex ) {
+
+		const parser = this;
+		const json = this.json;
+
+		const accessorDef = this.json.accessors[ accessorIndex ];
+
+		if ( accessorDef.bufferView === undefined && accessorDef.sparse === undefined ) {
+
+			const itemSize = WEBGL_TYPE_SIZES[ accessorDef.type ];
+			const TypedArray = WEBGL_COMPONENT_TYPES[ accessorDef.componentType ];
+			const normalized = accessorDef.normalized === true;
+
+			const array = new TypedArray( accessorDef.count * itemSize );
+			return Promise.resolve( new BufferAttribute( array, itemSize, normalized ) );
+
+		}
+
+		const pendingBufferViews = [];
+
+		if ( accessorDef.bufferView !== undefined ) {
+
+			pendingBufferViews.push( this.getDependency( 'bufferView', accessorDef.bufferView ) );
+
+		} else {
+
+			pendingBufferViews.push( null );
+
+		}
+
+		if ( accessorDef.sparse !== undefined ) {
+
+			pendingBufferViews.push( this.getDependency( 'bufferView', accessorDef.sparse.indices.bufferView ) );
+			pendingBufferViews.push( this.getDependency( 'bufferView', accessorDef.sparse.values.bufferView ) );
+
+		}
+
+		return Promise.all( pendingBufferViews ).then( function ( bufferViews ) {
+
+			const bufferView = bufferViews[ 0 ];
+
+			const itemSize = WEBGL_TYPE_SIZES[ accessorDef.type ];
+			const TypedArray = WEBGL_COMPONENT_TYPES[ accessorDef.componentType ];
+
+			// For VEC3: itemSize is 3, elementBytes is 4, itemBytes is 12.
+			const elementBytes = TypedArray.BYTES_PER_ELEMENT;
+			const itemBytes = elementBytes * itemSize;
+			const byteOffset = accessorDef.byteOffset || 0;
+			const byteStride = accessorDef.bufferView !== undefined ? json.bufferViews[ accessorDef.bufferView ].byteStride : undefined;
+			const normalized = accessorDef.normalized === true;
+			let array, bufferAttribute;
+
+			// The buffer is not interleaved if the stride is the item size in bytes.
+			if ( byteStride && byteStride !== itemBytes ) {
+
+				// Each "slice" of the buffer, as defined by 'count' elements of 'byteStride' bytes, gets its own InterleavedBuffer
+				// This makes sure that IBA.count reflects accessor.count properly
+				const ibSlice = Math.floor( byteOffset / byteStride );
+				const ibCacheKey = 'InterleavedBuffer:' + accessorDef.bufferView + ':' + accessorDef.componentType + ':' + ibSlice + ':' + accessorDef.count;
+				let ib = parser.cache.get( ibCacheKey );
+
+				if ( ! ib ) {
+
+					array = new TypedArray( bufferView, ibSlice * byteStride, accessorDef.count * byteStride / elementBytes );
+
+					// Integer parameters to IB/IBA are in array elements, not bytes.
+					ib = new InterleavedBuffer( array, byteStride / elementBytes );
+
+					parser.cache.add( ibCacheKey, ib );
+
+				}
+
+				bufferAttribute = new InterleavedBufferAttribute( ib, itemSize, ( byteOffset % byteStride ) / elementBytes, normalized );
+
+			} else {
+
+				if ( bufferView === null ) {
+
+					array = new TypedArray( accessorDef.count * itemSize );
+
+				} else {
+
+					array = new TypedArray( bufferView, byteOffset, accessorDef.count * itemSize );
+
+				}
+
+				bufferAttribute = new BufferAttribute( array, itemSize, normalized );
+
+			}
+
+			// https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#sparse-accessors
+			if ( accessorDef.sparse !== undefined ) {
+
+				const itemSizeIndices = WEBGL_TYPE_SIZES.SCALAR;
+				const TypedArrayIndices = WEBGL_COMPONENT_TYPES[ accessorDef.sparse.indices.componentType ];
+
+				const byteOffsetIndices = accessorDef.sparse.indices.byteOffset || 0;
+				const byteOffsetValues = accessorDef.sparse.values.byteOffset || 0;
+
+				const sparseIndices = new TypedArrayIndices( bufferViews[ 1 ], byteOffsetIndices, accessorDef.sparse.count * itemSizeIndices );
+				const sparseValues = new TypedArray( bufferViews[ 2 ], byteOffsetValues, accessorDef.sparse.count * itemSize );
+
+				if ( bufferView !== null ) {
+
+					// Avoid modifying the original ArrayBuffer, if the bufferView wasn't initialized with zeroes.
+					bufferAttribute = new BufferAttribute( bufferAttribute.array.slice(), bufferAttribute.itemSize, bufferAttribute.normalized );
+
+				}
+
+				for ( let i = 0, il = sparseIndices.length; i < il; i ++ ) {
+
+					const index = sparseIndices[ i ];
+
+					bufferAttribute.setX( index, sparseValues[ i * itemSize ] );
+					if ( itemSize >= 2 ) bufferAttribute.setY( index, sparseValues[ i * itemSize + 1 ] );
+					if ( itemSize >= 3 ) bufferAttribute.setZ( index, sparseValues[ i * itemSize + 2 ] );
+					if ( itemSize >= 4 ) bufferAttribute.setW( index, sparseValues[ i * itemSize + 3 ] );
+					if ( itemSize >= 5 ) throw new Error( 'THREE.GLTFLoader: Unsupported itemSize in sparse BufferAttribute.' );
+
+				}
+
+			}
+
+			return bufferAttribute;
+
+		} );
+
+	}
+
+	/**
+	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#textures
+	 * @param {number} textureIndex
+	 * @return {Promise<THREE.Texture|null>}
+	 */
+	loadTexture( textureIndex ) {
+
+		const json = this.json;
+		const options = this.options;
+		const textureDef = json.textures[ textureIndex ];
+		const sourceIndex = textureDef.source;
+		const sourceDef = json.images[ sourceIndex ];
+
+		let loader = this.textureLoader;
+
+		if ( sourceDef.uri ) {
+
+			const handler = options.manager.getHandler( sourceDef.uri );
+			if ( handler !== null ) loader = handler;
+
+		}
+
+		return this.loadTextureImage( textureIndex, sourceIndex, loader );
+
+	}
+
+	loadTextureImage( textureIndex, sourceIndex, loader ) {
+
+		const parser = this;
+		const json = this.json;
+
+		const textureDef = json.textures[ textureIndex ];
+		const sourceDef = json.images[ sourceIndex ];
+
+		const cacheKey = ( sourceDef.uri || sourceDef.bufferView ) + ':' + textureDef.sampler;
+
+		if ( this.textureCache[ cacheKey ] ) {
+
+			// See https://github.com/mrdoob/three.js/issues/21559.
+			return this.textureCache[ cacheKey ];
+
+		}
+
+		const promise = this.loadImageSource( sourceIndex, loader ).then( function ( texture ) {
+
+			texture.flipY = false;
+
+			texture.name = textureDef.name || sourceDef.name || '';
+
+			if ( texture.name === '' && typeof sourceDef.uri === 'string' && sourceDef.uri.startsWith( 'data:image/' ) === false ) {
+
+				texture.name = sourceDef.uri;
+
+			}
+
+			const samplers = json.samplers || {};
+			const sampler = samplers[ textureDef.sampler ] || {};
+
+			texture.magFilter = WEBGL_FILTERS[ sampler.magFilter ] || LinearFilter;
+			texture.minFilter = WEBGL_FILTERS[ sampler.minFilter ] || LinearMipmapLinearFilter;
+			texture.wrapS = WEBGL_WRAPPINGS[ sampler.wrapS ] || RepeatWrapping;
+			texture.wrapT = WEBGL_WRAPPINGS[ sampler.wrapT ] || RepeatWrapping;
+
+			parser.associations.set( texture, { textures: textureIndex } );
+
+			return texture;
+
+		} ).catch( function () {
+
+			return null;
+
+		} );
+
+		this.textureCache[ cacheKey ] = promise;
+
+		return promise;
+
+	}
+
+	loadImageSource( sourceIndex, loader ) {
+
+		const parser = this;
+		const json = this.json;
+		const options = this.options;
+
+		if ( this.sourceCache[ sourceIndex ] !== undefined ) {
+
+			return this.sourceCache[ sourceIndex ].then( ( texture ) => texture.clone() );
+
+		}
+
+		const sourceDef = json.images[ sourceIndex ];
+
+		const URL = self.URL || self.webkitURL;
+
+		let sourceURI = sourceDef.uri || '';
+		let isObjectURL = false;
+
+		if ( sourceDef.bufferView !== undefined ) {
+
+			// Load binary image data from bufferView, if provided.
+
+			sourceURI = parser.getDependency( 'bufferView', sourceDef.bufferView ).then( function ( bufferView ) {
+
+				isObjectURL = true;
+				const blob = new Blob( [ bufferView ], { type: sourceDef.mimeType } );
+				sourceURI = URL.createObjectURL( blob );
+				return sourceURI;
+
+			} );
+
+		} else if ( sourceDef.uri === undefined ) {
+
+			throw new Error( 'THREE.GLTFLoader: Image ' + sourceIndex + ' is missing URI and bufferView' );
+
+		}
+
+		const promise = Promise.resolve( sourceURI ).then( function ( sourceURI ) {
+
+			return new Promise( function ( resolve, reject ) {
+
+				let onLoad = resolve;
+
+				if ( loader.isImageBitmapLoader === true ) {
+
+					onLoad = function ( imageBitmap ) {
+
+						const texture = new Texture( imageBitmap );
+						texture.needsUpdate = true;
+
+						resolve( texture );
+
+					};
+
+				}
+
+				loader.load( LoaderUtils.resolveURL( sourceURI, options.path ), onLoad, undefined, reject );
+
+			} );
+
+		} ).then( function ( texture ) {
+
+			// Clean up resources and configure Texture.
+
+			if ( isObjectURL === true ) {
+
+				URL.revokeObjectURL( sourceURI );
+
+			}
+
+			texture.userData.mimeType = sourceDef.mimeType || getImageURIMimeType( sourceDef.uri );
+
+			return texture;
+
+		} ).catch( function ( error ) {
+
+			console.error( 'THREE.GLTFLoader: Couldn\'t load texture', sourceURI );
+			throw error;
+
+		} );
+
+		this.sourceCache[ sourceIndex ] = promise;
+		return promise;
+
+	}
+
+	/**
+	 * Asynchronously assigns a texture to the given material parameters.
+	 * @param {Object} materialParams
+	 * @param {string} mapName
+	 * @param {Object} mapDef
+	 * @return {Promise<Texture>}
+	 */
+	assignTexture( materialParams, mapName, mapDef, colorSpace ) {
+
+		const parser = this;
+
+		return this.getDependency( 'texture', mapDef.index ).then( function ( texture ) {
+
+			if ( ! texture ) return null;
+
+			if ( mapDef.texCoord !== undefined && mapDef.texCoord > 0 ) {
+
+				texture = texture.clone();
+				texture.channel = mapDef.texCoord;
+
+			}
+
+			if ( parser.extensions[ EXTENSIONS.KHR_TEXTURE_TRANSFORM ] ) {
+
+				const transform = mapDef.extensions !== undefined ? mapDef.extensions[ EXTENSIONS.KHR_TEXTURE_TRANSFORM ] : undefined;
+
+				if ( transform ) {
+
+					const gltfReference = parser.associations.get( texture );
+					texture = parser.extensions[ EXTENSIONS.KHR_TEXTURE_TRANSFORM ].extendTexture( texture, transform );
+					parser.associations.set( texture, gltfReference );
+
+				}
+
+			}
+
+			if ( colorSpace !== undefined ) {
+
+				texture.colorSpace = colorSpace;
+
+			}
+
+			materialParams[ mapName ] = texture;
+
+			return texture;
+
+		} );
+
+	}
+
+	/**
+	 * Assigns final material to a Mesh, Line, or Points instance. The instance
+	 * already has a material (generated from the glTF material options alone)
+	 * but reuse of the same glTF material may require multiple threejs materials
+	 * to accommodate different primitive types, defines, etc. New materials will
+	 * be created if necessary, and reused from a cache.
+	 * @param  {Object3D} mesh Mesh, Line, or Points instance.
+	 */
+	assignFinalMaterial( mesh ) {
+
+		const geometry = mesh.geometry;
+		let material = mesh.material;
+
+		const useDerivativeTangents = geometry.attributes.tangent === undefined;
+		const useVertexColors = geometry.attributes.color !== undefined;
+		const useFlatShading = geometry.attributes.normal === undefined;
+
+		if ( mesh.isPoints ) {
+
+			const cacheKey = 'PointsMaterial:' + material.uuid;
+
+			let pointsMaterial = this.cache.get( cacheKey );
+
+			if ( ! pointsMaterial ) {
+
+				pointsMaterial = new PointsMaterial();
+				Material.prototype.copy.call( pointsMaterial, material );
+				pointsMaterial.color.copy( material.color );
+				pointsMaterial.map = material.map;
+				pointsMaterial.sizeAttenuation = false; // glTF spec says points should be 1px
+
+				this.cache.add( cacheKey, pointsMaterial );
+
+			}
+
+			material = pointsMaterial;
+
+		} else if ( mesh.isLine ) {
+
+			const cacheKey = 'LineBasicMaterial:' + material.uuid;
+
+			let lineMaterial = this.cache.get( cacheKey );
+
+			if ( ! lineMaterial ) {
+
+				lineMaterial = new LineBasicMaterial();
+				Material.prototype.copy.call( lineMaterial, material );
+				lineMaterial.color.copy( material.color );
+				lineMaterial.map = material.map;
+
+				this.cache.add( cacheKey, lineMaterial );
+
+			}
+
+			material = lineMaterial;
+
+		}
+
+		// Clone the material if it will be modified
+		if ( useDerivativeTangents || useVertexColors || useFlatShading ) {
+
+			let cacheKey = 'ClonedMaterial:' + material.uuid + ':';
+
+			if ( useDerivativeTangents ) cacheKey += 'derivative-tangents:';
+			if ( useVertexColors ) cacheKey += 'vertex-colors:';
+			if ( useFlatShading ) cacheKey += 'flat-shading:';
+
+			let cachedMaterial = this.cache.get( cacheKey );
+
+			if ( ! cachedMaterial ) {
+
+				cachedMaterial = material.clone();
+
+				if ( useVertexColors ) cachedMaterial.vertexColors = true;
+				if ( useFlatShading ) cachedMaterial.flatShading = true;
+
+				if ( useDerivativeTangents ) {
+
+					// https://github.com/mrdoob/three.js/issues/11438#issuecomment-507003995
+					if ( cachedMaterial.normalScale ) cachedMaterial.normalScale.y *= - 1;
+					if ( cachedMaterial.clearcoatNormalScale ) cachedMaterial.clearcoatNormalScale.y *= - 1;
+
+				}
+
+				this.cache.add( cacheKey, cachedMaterial );
+
+				this.associations.set( cachedMaterial, this.associations.get( material ) );
+
+			}
+
+			material = cachedMaterial;
+
+		}
+
+		mesh.material = material;
+
+	}
+
+	getMaterialType( /* materialIndex */ ) {
+
+		return MeshStandardMaterial;
+
+	}
+
+	/**
+	 * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#materials
+	 * @param {number} materialIndex
+	 * @return {Promise<Material>}
+	 */
+	loadMaterial( materialIndex ) {
+
+		const parser = this;
+		const json = this.json;
+		const extensions = this.extensions;
+		const materialDef = json.materials[ materialIndex ];
+
+		let materialType;
+		const materialParams = {};
+		const materialExtensions = materialDef.extensions || {};
+
+		const pending = [];
+
+		if ( materialExtensions[ EXTENSIONS.KHR_MATERIALS_UNLIT ] ) {
+
+			const kmuExtension = extensions[ EXTENSIONS.KHR_MATERIALS_UNLIT ];
+			materialType = kmuExtension.getMaterialType();
+			pending.push( kmuExtension.extendParams( materialParams, materialDef, parser ) );
+
+		} else {
+
+			// Specification:
+			// https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#metallic-roughness-material
+
+			const metallicRoughness = materialDef.pbrMetallicRoughness || {};
+
+			materialParams.color = new Color( 1.0, 1.0, 1.0 );
+			materialParams.opacity = 1.0;
+
+			if ( Array.isArray( metallicRoughness.baseColorFactor ) ) {
+
+				const array = metallicRoughness.baseColorFactor;
+
+				materialParams.color.setRGB( array[ 0 ], array[ 1 ], array[ 2 ], LinearSRGBColorSpace );
+				materialParams.opacity = array[ 3 ];
+
+			}
+
+			if ( metallicRoughness.baseColorTexture !== undefined ) {
+
+				pending.push( parser.assignTexture( materialParams, 'map', metallicRoughness.baseColorTexture, SRGBColorSpace ) );
+
+			}
+
+			materialParams.metalness = metallicRoughness.metallicFactor !== undefined ? metallicRoughness.metallicFactor : 1.0;
+			materialParams.roughness = metallicRoughness.roughnessFactor !== undefined ? metallicRoughness.roughnessFactor : 1.0;
+
+			if ( metallicRoughness.metallicRoughnessTexture !== undefined ) {
+
+				pending.push( parser.assignTexture( materialParams, 'metalnessMap', metallicRoughness.metallicRoughnessTexture ) );
+				pending.push( parser.assignTexture( materialParams, 'roughnessMap', metallicRoughness.metallicRoughnessTexture ) );
+
+			}
+
+			materialType = this._invokeOne( function ( ext ) {
+
+				return ext.getMaterialType && ext.getMaterialType( materialIndex );
+
+			} );
+
+			pending.push( Promise.all( this._invokeAll( function ( ext ) {
+
+				return ext.extendMaterialParams && ext.extendMaterialParams( materialIndex, materialParams );
+
+			} ) ) );
+
+		}
+
+		if ( materialDef.doubleSided === true ) {
+
+			materialParams.side = DoubleSide;
+
+		}
+
+		const alphaMode = materialDef.alphaMode || ALPHA_MODES.OPAQUE;
+
+		if ( alphaMode === ALPHA_MODES.BLEND ) {
+
+			materialParams.transparent = true;
+
+			// See: https://github.com/mrdoob/three.js/issues/17706
+			materialParams.depthWrite = false;
+
+		} else {
+
+			materialParams.transparent = false;
+
+			if ( alphaMode === ALPHA_MODES.MASK ) {
+
+				materialParams.alphaTest = materialDef.alphaCutoff !== undefined ? materialDef.alphaCutoff : 0.5;
+
+			}
+
+		}
+
+		if ( materialDef.normalTexture !== undefined && materialType !== MeshBasicMaterial ) {
+
+			pending.push( parser.assignTexture( materialParams, 'normalMap', materialDef.normalTexture ) );
+
+			materialParams.normalScale = new Vector2( 1, 1 );
+
+			if ( materialDef.normalTexture.scale !== undefined ) {
+
+				const scale = materialDef.normalTexture.scale;
+
+				materialParams.normalScale.set( scale, scale );
+
+			}
+
+		}
+
+		if ( materialDef.occlusionTexture !== undefined && materialType !== MeshBasicMaterial ) {
+
+			pending.push( parser.assignTexture( materialParams, 'aoMap', materialDef.occlusionTexture ) );
+
+			if ( materialDef.occlusionTexture.strength !== undefined ) {
+
+				materialParams.aoMapIntensity = materialDef.occlusionTexture.strength;
+
+			}
+
+		}
+
+		if ( materialDef.emissiveFactor !== undefined && materialType !== MeshBasicMaterial ) {
+
+			const emissiveFactor = materialDef.emissiveFactor;
+			materialParams.emissive = new Color().setRGB( emissiveFactor[ 0 ], emissiveFactor[ 1 ], emissiveFactor[ 2 ], LinearSRGBColorSpace );
+
+		}
+
+		if ( materialDef.emissiveTexture !== undefined && materialType !== MeshBasicMaterial ) {
+
+			pending.push( parser.assignTexture( materialParams, 'emissiveMap', materialDef.emissiveTexture, SRGBColorSpace ) );
+
+		}
+
+		return Promise.all( pending ).then( function () {
+
+			const material = new materialType( materialParams );
+
+			if ( materialDef.name ) material.name = materialDef.name;
+
+			assignExtrasToUserData( material, materialDef );
+
+			parser.associations.set( material, { materials: materialIndex } );
+
+			if ( materialDef.extensions ) addUnknownExtensionsToUserData( extensions, material, materialDef );
+
+			return material;
+
+		} );
+
+	}
+
+	/** When Object3D instances are targeted by animation, they need unique names. */
+	createUniqueName( originalName ) {
+
+		const sanitizedName = PropertyBinding.sanitizeNodeName( originalName || '' );
+
+		if ( sanitizedName in this.nodeNamesUsed ) {
+
+			return sanitizedName + '_' + ( ++ this.nodeNamesUsed[ sanitizedName ] );
+
+		} else {
+
+			this.nodeNamesUsed[ sanitizedName ] = 0;
+
+			return sanitizedName;
+
+		}
+
+	}
+
+	/**
+	 * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#geometry
+	 *
+	 * Creates BufferGeometries from primitives.
+	 *
+	 * @param {Array<GLTF.Primitive>} primitives
+	 * @return {Promise<Array<BufferGeometry>>}
+	 */
+	loadGeometries( primitives ) {
+
+		const parser = this;
+		const extensions = this.extensions;
+		const cache = this.primitiveCache;
+
+		function createDracoPrimitive( primitive ) {
+
+			return extensions[ EXTENSIONS.KHR_DRACO_MESH_COMPRESSION ]
+				.decodePrimitive( primitive, parser )
+				.then( function ( geometry ) {
+
+					return addPrimitiveAttributes( geometry, primitive, parser );
+
+				} );
+
+		}
+
+		const pending = [];
+
+		for ( let i = 0, il = primitives.length; i < il; i ++ ) {
+
+			const primitive = primitives[ i ];
+			const cacheKey = createPrimitiveKey( primitive );
+
+			// See if we've already created this geometry
+			const cached = cache[ cacheKey ];
+
+			if ( cached ) {
+
+				// Use the cached geometry if it exists
+				pending.push( cached.promise );
+
+			} else {
+
+				let geometryPromise;
+
+				if ( primitive.extensions && primitive.extensions[ EXTENSIONS.KHR_DRACO_MESH_COMPRESSION ] ) {
+
+					// Use DRACO geometry if available
+					geometryPromise = createDracoPrimitive( primitive );
+
+				} else {
+
+					// Otherwise create a new geometry
+					geometryPromise = addPrimitiveAttributes( new BufferGeometry(), primitive, parser );
+
+				}
+
+				// Cache this geometry
+				cache[ cacheKey ] = { primitive: primitive, promise: geometryPromise };
+
+				pending.push( geometryPromise );
+
+			}
+
+		}
+
+		return Promise.all( pending );
+
+	}
+
+	/**
+	 * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#meshes
+	 * @param {number} meshIndex
+	 * @return {Promise<Group|Mesh|SkinnedMesh>}
+	 */
+	loadMesh( meshIndex ) {
+
+		const parser = this;
+		const json = this.json;
+		const extensions = this.extensions;
+
+		const meshDef = json.meshes[ meshIndex ];
+		const primitives = meshDef.primitives;
+
+		const pending = [];
+
+		for ( let i = 0, il = primitives.length; i < il; i ++ ) {
+
+			const material = primitives[ i ].material === undefined
+				? createDefaultMaterial( this.cache )
+				: this.getDependency( 'material', primitives[ i ].material );
+
+			pending.push( material );
+
+		}
+
+		pending.push( parser.loadGeometries( primitives ) );
+
+		return Promise.all( pending ).then( function ( results ) {
+
+			const materials = results.slice( 0, results.length - 1 );
+			const geometries = results[ results.length - 1 ];
+
+			const meshes = [];
+
+			for ( let i = 0, il = geometries.length; i < il; i ++ ) {
+
+				const geometry = geometries[ i ];
+				const primitive = primitives[ i ];
+
+				// 1. create Mesh
+
+				let mesh;
+
+				const material = materials[ i ];
+
+				if ( primitive.mode === WEBGL_CONSTANTS.TRIANGLES ||
+						primitive.mode === WEBGL_CONSTANTS.TRIANGLE_STRIP ||
+						primitive.mode === WEBGL_CONSTANTS.TRIANGLE_FAN ||
+						primitive.mode === undefined ) {
+
+					// .isSkinnedMesh isn't in glTF spec. See ._markDefs()
+					mesh = meshDef.isSkinnedMesh === true
+						? new SkinnedMesh( geometry, material )
+						: new Mesh( geometry, material );
+
+					if ( mesh.isSkinnedMesh === true ) {
+
+						// normalize skin weights to fix malformed assets (see #15319)
+						mesh.normalizeSkinWeights();
+
+					}
+
+					if ( primitive.mode === WEBGL_CONSTANTS.TRIANGLE_STRIP ) {
+
+						mesh.geometry = toTrianglesDrawMode( mesh.geometry, TriangleStripDrawMode );
+
+					} else if ( primitive.mode === WEBGL_CONSTANTS.TRIANGLE_FAN ) {
+
+						mesh.geometry = toTrianglesDrawMode( mesh.geometry, TriangleFanDrawMode );
+
+					}
+
+				} else if ( primitive.mode === WEBGL_CONSTANTS.LINES ) {
+
+					mesh = new LineSegments( geometry, material );
+
+				} else if ( primitive.mode === WEBGL_CONSTANTS.LINE_STRIP ) {
+
+					mesh = new Line( geometry, material );
+
+				} else if ( primitive.mode === WEBGL_CONSTANTS.LINE_LOOP ) {
+
+					mesh = new LineLoop( geometry, material );
+
+				} else if ( primitive.mode === WEBGL_CONSTANTS.POINTS ) {
+
+					mesh = new Points( geometry, material );
+
+				} else {
+
+					throw new Error( 'THREE.GLTFLoader: Primitive mode unsupported: ' + primitive.mode );
+
+				}
+
+				if ( Object.keys( mesh.geometry.morphAttributes ).length > 0 ) {
+
+					updateMorphTargets( mesh, meshDef );
+
+				}
+
+				mesh.name = parser.createUniqueName( meshDef.name || ( 'mesh_' + meshIndex ) );
+
+				assignExtrasToUserData( mesh, meshDef );
+
+				if ( primitive.extensions ) addUnknownExtensionsToUserData( extensions, mesh, primitive );
+
+				parser.assignFinalMaterial( mesh );
+
+				meshes.push( mesh );
+
+			}
+
+			for ( let i = 0, il = meshes.length; i < il; i ++ ) {
+
+				parser.associations.set( meshes[ i ], {
+					meshes: meshIndex,
+					primitives: i
+				} );
+
+			}
+
+			if ( meshes.length === 1 ) {
+
+				if ( meshDef.extensions ) addUnknownExtensionsToUserData( extensions, meshes[ 0 ], meshDef );
+
+				return meshes[ 0 ];
+
+			}
+
+			const group = new Group();
+
+			if ( meshDef.extensions ) addUnknownExtensionsToUserData( extensions, group, meshDef );
+
+			parser.associations.set( group, { meshes: meshIndex } );
+
+			for ( let i = 0, il = meshes.length; i < il; i ++ ) {
+
+				group.add( meshes[ i ] );
+
+			}
+
+			return group;
+
+		} );
+
+	}
+
+	/**
+	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#cameras
+	 * @param {number} cameraIndex
+	 * @return {Promise<THREE.Camera>}
+	 */
+	loadCamera( cameraIndex ) {
+
+		let camera;
+		const cameraDef = this.json.cameras[ cameraIndex ];
+		const params = cameraDef[ cameraDef.type ];
+
+		if ( ! params ) {
+
+			console.warn( 'THREE.GLTFLoader: Missing camera parameters.' );
+			return;
+
+		}
+
+		if ( cameraDef.type === 'perspective' ) {
+
+			camera = new PerspectiveCamera( MathUtils.radToDeg( params.yfov ), params.aspectRatio || 1, params.znear || 1, params.zfar || 2e6 );
+
+		} else if ( cameraDef.type === 'orthographic' ) {
+
+			camera = new OrthographicCamera( - params.xmag, params.xmag, params.ymag, - params.ymag, params.znear, params.zfar );
+
+		}
+
+		if ( cameraDef.name ) camera.name = this.createUniqueName( cameraDef.name );
+
+		assignExtrasToUserData( camera, cameraDef );
+
+		return Promise.resolve( camera );
+
+	}
+
+	/**
+	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#skins
+	 * @param {number} skinIndex
+	 * @return {Promise<Skeleton>}
+	 */
+	loadSkin( skinIndex ) {
+
+		const skinDef = this.json.skins[ skinIndex ];
+
+		const pending = [];
+
+		for ( let i = 0, il = skinDef.joints.length; i < il; i ++ ) {
+
+			pending.push( this._loadNodeShallow( skinDef.joints[ i ] ) );
+
+		}
+
+		if ( skinDef.inverseBindMatrices !== undefined ) {
+
+			pending.push( this.getDependency( 'accessor', skinDef.inverseBindMatrices ) );
+
+		} else {
+
+			pending.push( null );
+
+		}
+
+		return Promise.all( pending ).then( function ( results ) {
+
+			const inverseBindMatrices = results.pop();
+			const jointNodes = results;
+
+			// Note that bones (joint nodes) may or may not be in the
+			// scene graph at this time.
+
+			const bones = [];
+			const boneInverses = [];
+
+			for ( let i = 0, il = jointNodes.length; i < il; i ++ ) {
+
+				const jointNode = jointNodes[ i ];
+
+				if ( jointNode ) {
+
+					bones.push( jointNode );
+
+					const mat = new Matrix4();
+
+					if ( inverseBindMatrices !== null ) {
+
+						mat.fromArray( inverseBindMatrices.array, i * 16 );
+
+					}
+
+					boneInverses.push( mat );
+
+				} else {
+
+					console.warn( 'THREE.GLTFLoader: Joint "%s" could not be found.', skinDef.joints[ i ] );
+
+				}
+
+			}
+
+			return new Skeleton( bones, boneInverses );
+
+		} );
+
+	}
+
+	/**
+	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#animations
+	 * @param {number} animationIndex
+	 * @return {Promise<AnimationClip>}
+	 */
+	loadAnimation( animationIndex ) {
+
+		const json = this.json;
+		const parser = this;
+
+		const animationDef = json.animations[ animationIndex ];
+		const animationName = animationDef.name ? animationDef.name : 'animation_' + animationIndex;
+
+		const pendingNodes = [];
+		const pendingInputAccessors = [];
+		const pendingOutputAccessors = [];
+		const pendingSamplers = [];
+		const pendingTargets = [];
+
+		for ( let i = 0, il = animationDef.channels.length; i < il; i ++ ) {
+
+			const channel = animationDef.channels[ i ];
+			const sampler = animationDef.samplers[ channel.sampler ];
+			const target = channel.target;
+			const name = target.node;
+			const input = animationDef.parameters !== undefined ? animationDef.parameters[ sampler.input ] : sampler.input;
+			const output = animationDef.parameters !== undefined ? animationDef.parameters[ sampler.output ] : sampler.output;
+
+			if ( target.node === undefined ) continue;
+
+			pendingNodes.push( this.getDependency( 'node', name ) );
+			pendingInputAccessors.push( this.getDependency( 'accessor', input ) );
+			pendingOutputAccessors.push( this.getDependency( 'accessor', output ) );
+			pendingSamplers.push( sampler );
+			pendingTargets.push( target );
+
+		}
+
+		return Promise.all( [
+
+			Promise.all( pendingNodes ),
+			Promise.all( pendingInputAccessors ),
+			Promise.all( pendingOutputAccessors ),
+			Promise.all( pendingSamplers ),
+			Promise.all( pendingTargets )
+
+		] ).then( function ( dependencies ) {
+
+			const nodes = dependencies[ 0 ];
+			const inputAccessors = dependencies[ 1 ];
+			const outputAccessors = dependencies[ 2 ];
+			const samplers = dependencies[ 3 ];
+			const targets = dependencies[ 4 ];
+
+			const tracks = [];
+
+			for ( let i = 0, il = nodes.length; i < il; i ++ ) {
+
+				const node = nodes[ i ];
+				const inputAccessor = inputAccessors[ i ];
+				const outputAccessor = outputAccessors[ i ];
+				const sampler = samplers[ i ];
+				const target = targets[ i ];
+
+				if ( node === undefined ) continue;
+
+				if ( node.updateMatrix ) {
+
+					node.updateMatrix();
+
+				}
+
+				const createdTracks = parser._createAnimationTracks( node, inputAccessor, outputAccessor, sampler, target );
+
+				if ( createdTracks ) {
+
+					for ( let k = 0; k < createdTracks.length; k ++ ) {
+
+						tracks.push( createdTracks[ k ] );
+
+					}
+
+				}
+
+			}
+
+			return new AnimationClip( animationName, undefined, tracks );
+
+		} );
+
+	}
+
+	createNodeMesh( nodeIndex ) {
+
+		const json = this.json;
+		const parser = this;
+		const nodeDef = json.nodes[ nodeIndex ];
+
+		if ( nodeDef.mesh === undefined ) return null;
+
+		return parser.getDependency( 'mesh', nodeDef.mesh ).then( function ( mesh ) {
+
+			const node = parser._getNodeRef( parser.meshCache, nodeDef.mesh, mesh );
+
+			// if weights are provided on the node, override weights on the mesh.
+			if ( nodeDef.weights !== undefined ) {
+
+				node.traverse( function ( o ) {
+
+					if ( ! o.isMesh ) return;
+
+					for ( let i = 0, il = nodeDef.weights.length; i < il; i ++ ) {
+
+						o.morphTargetInfluences[ i ] = nodeDef.weights[ i ];
+
+					}
+
+				} );
+
+			}
+
+			return node;
+
+		} );
+
+	}
+
+	/**
+	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#nodes-and-hierarchy
+	 * @param {number} nodeIndex
+	 * @return {Promise<Object3D>}
+	 */
+	loadNode( nodeIndex ) {
+
+		const json = this.json;
+		const parser = this;
+
+		const nodeDef = json.nodes[ nodeIndex ];
+
+		const nodePending = parser._loadNodeShallow( nodeIndex );
+
+		const childPending = [];
+		const childrenDef = nodeDef.children || [];
+
+		for ( let i = 0, il = childrenDef.length; i < il; i ++ ) {
+
+			childPending.push( parser.getDependency( 'node', childrenDef[ i ] ) );
+
+		}
+
+		const skeletonPending = nodeDef.skin === undefined
+			? Promise.resolve( null )
+			: parser.getDependency( 'skin', nodeDef.skin );
+
+		return Promise.all( [
+			nodePending,
+			Promise.all( childPending ),
+			skeletonPending
+		] ).then( function ( results ) {
+
+			const node = results[ 0 ];
+			const children = results[ 1 ];
+			const skeleton = results[ 2 ];
+
+			if ( skeleton !== null ) {
+
+				// This full traverse should be fine because
+				// child glTF nodes have not been added to this node yet.
+				node.traverse( function ( mesh ) {
+
+					if ( ! mesh.isSkinnedMesh ) return;
+
+					mesh.bind( skeleton, _identityMatrix );
+
+				} );
+
+			}
+
+			for ( let i = 0, il = children.length; i < il; i ++ ) {
+
+				node.add( children[ i ] );
+
+			}
+
+			return node;
+
+		} );
+
+	}
+
+	// ._loadNodeShallow() parses a single node.
+	// skin and child nodes are created and added in .loadNode() (no '_' prefix).
+	_loadNodeShallow( nodeIndex ) {
+
+		const json = this.json;
+		const extensions = this.extensions;
+		const parser = this;
+
+		// This method is called from .loadNode() and .loadSkin().
+		// Cache a node to avoid duplication.
+
+		if ( this.nodeCache[ nodeIndex ] !== undefined ) {
+
+			return this.nodeCache[ nodeIndex ];
+
+		}
+
+		const nodeDef = json.nodes[ nodeIndex ];
+
+		// reserve node's name before its dependencies, so the root has the intended name.
+		const nodeName = nodeDef.name ? parser.createUniqueName( nodeDef.name ) : '';
+
+		const pending = [];
+
+		const meshPromise = parser._invokeOne( function ( ext ) {
+
+			return ext.createNodeMesh && ext.createNodeMesh( nodeIndex );
+
+		} );
+
+		if ( meshPromise ) {
+
+			pending.push( meshPromise );
+
+		}
+
+		if ( nodeDef.camera !== undefined ) {
+
+			pending.push( parser.getDependency( 'camera', nodeDef.camera ).then( function ( camera ) {
+
+				return parser._getNodeRef( parser.cameraCache, nodeDef.camera, camera );
+
+			} ) );
+
+		}
+
+		parser._invokeAll( function ( ext ) {
+
+			return ext.createNodeAttachment && ext.createNodeAttachment( nodeIndex );
+
+		} ).forEach( function ( promise ) {
+
+			pending.push( promise );
+
+		} );
+
+		this.nodeCache[ nodeIndex ] = Promise.all( pending ).then( function ( objects ) {
+
+			let node;
+
+			// .isBone isn't in glTF spec. See ._markDefs
+			if ( nodeDef.isBone === true ) {
+
+				node = new Bone();
+
+			} else if ( objects.length > 1 ) {
+
+				node = new Group();
+
+			} else if ( objects.length === 1 ) {
+
+				node = objects[ 0 ];
+
+			} else {
+
+				node = new Object3D();
+
+			}
+
+			if ( node !== objects[ 0 ] ) {
+
+				for ( let i = 0, il = objects.length; i < il; i ++ ) {
+
+					node.add( objects[ i ] );
+
+				}
+
+			}
+
+			if ( nodeDef.name ) {
+
+				node.userData.name = nodeDef.name;
+				node.name = nodeName;
+
+			}
+
+			assignExtrasToUserData( node, nodeDef );
+
+			if ( nodeDef.extensions ) addUnknownExtensionsToUserData( extensions, node, nodeDef );
+
+			if ( nodeDef.matrix !== undefined ) {
+
+				const matrix = new Matrix4();
+				matrix.fromArray( nodeDef.matrix );
+				node.applyMatrix4( matrix );
+
+			} else {
+
+				if ( nodeDef.translation !== undefined ) {
+
+					node.position.fromArray( nodeDef.translation );
+
+				}
+
+				if ( nodeDef.rotation !== undefined ) {
+
+					node.quaternion.fromArray( nodeDef.rotation );
+
+				}
+
+				if ( nodeDef.scale !== undefined ) {
+
+					node.scale.fromArray( nodeDef.scale );
+
+				}
+
+			}
+
+			if ( ! parser.associations.has( node ) ) {
+
+				parser.associations.set( node, {} );
+
+			}
+
+			parser.associations.get( node ).nodes = nodeIndex;
+
+			return node;
+
+		} );
+
+		return this.nodeCache[ nodeIndex ];
+
+	}
+
+	/**
+	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#scenes
+	 * @param {number} sceneIndex
+	 * @return {Promise<Group>}
+	 */
+	loadScene( sceneIndex ) {
+
+		const extensions = this.extensions;
+		const sceneDef = this.json.scenes[ sceneIndex ];
+		const parser = this;
+
+		// Loader returns Group, not Scene.
+		// See: https://github.com/mrdoob/three.js/issues/18342#issuecomment-578981172
+		const scene = new Group();
+		if ( sceneDef.name ) scene.name = parser.createUniqueName( sceneDef.name );
+
+		assignExtrasToUserData( scene, sceneDef );
+
+		if ( sceneDef.extensions ) addUnknownExtensionsToUserData( extensions, scene, sceneDef );
+
+		const nodeIds = sceneDef.nodes || [];
+
+		const pending = [];
+
+		for ( let i = 0, il = nodeIds.length; i < il; i ++ ) {
+
+			pending.push( parser.getDependency( 'node', nodeIds[ i ] ) );
+
+		}
+
+		return Promise.all( pending ).then( function ( nodes ) {
+
+			for ( let i = 0, il = nodes.length; i < il; i ++ ) {
+
+				scene.add( nodes[ i ] );
+
+			}
+
+			// Removes dangling associations, associations that reference a node that
+			// didn't make it into the scene.
+			const reduceAssociations = ( node ) => {
+
+				const reducedAssociations = new Map();
+
+				for ( const [ key, value ] of parser.associations ) {
+
+					if ( key instanceof Material || key instanceof Texture ) {
+
+						reducedAssociations.set( key, value );
+
+					}
+
+				}
+
+				node.traverse( ( node ) => {
+
+					const mappings = parser.associations.get( node );
+
+					if ( mappings != null ) {
+
+						reducedAssociations.set( node, mappings );
+
+					}
+
+				} );
+
+				return reducedAssociations;
+
+			};
+
+			parser.associations = reduceAssociations( scene );
+
+			return scene;
+
+		} );
+
+	}
+
+	_createAnimationTracks( node, inputAccessor, outputAccessor, sampler, target ) {
+
+		const tracks = [];
+
+		const targetName = node.name ? node.name : node.uuid;
+		const targetNames = [];
+
+		if ( PATH_PROPERTIES[ target.path ] === PATH_PROPERTIES.weights ) {
+
+			node.traverse( function ( object ) {
+
+				if ( object.morphTargetInfluences ) {
+
+					targetNames.push( object.name ? object.name : object.uuid );
+
+				}
+
+			} );
+
+		} else {
+
+			targetNames.push( targetName );
+
+		}
+
+		let TypedKeyframeTrack;
+
+		switch ( PATH_PROPERTIES[ target.path ] ) {
+
+			case PATH_PROPERTIES.weights:
+
+				TypedKeyframeTrack = NumberKeyframeTrack;
+				break;
+
+			case PATH_PROPERTIES.rotation:
+
+				TypedKeyframeTrack = QuaternionKeyframeTrack;
+				break;
+
+			case PATH_PROPERTIES.position:
+			case PATH_PROPERTIES.scale:
+
+				TypedKeyframeTrack = VectorKeyframeTrack;
+				break;
+
+			default:
+
+				switch ( outputAccessor.itemSize ) {
+
+					case 1:
+						TypedKeyframeTrack = NumberKeyframeTrack;
+						break;
+					case 2:
+					case 3:
+					default:
+						TypedKeyframeTrack = VectorKeyframeTrack;
+						break;
+
+				}
+
+				break;
+
+		}
+
+		const interpolation = sampler.interpolation !== undefined ? INTERPOLATION[ sampler.interpolation ] : InterpolateLinear;
+
+
+		const outputArray = this._getArrayFromAccessor( outputAccessor );
+
+		for ( let j = 0, jl = targetNames.length; j < jl; j ++ ) {
+
+			const track = new TypedKeyframeTrack(
+				targetNames[ j ] + '.' + PATH_PROPERTIES[ target.path ],
+				inputAccessor.array,
+				outputArray,
+				interpolation
+			);
+
+			// Override interpolation with custom factory method.
+			if ( sampler.interpolation === 'CUBICSPLINE' ) {
+
+				this._createCubicSplineTrackInterpolant( track );
+
+			}
+
+			tracks.push( track );
+
+		}
+
+		return tracks;
+
+	}
+
+	_getArrayFromAccessor( accessor ) {
+
+		let outputArray = accessor.array;
+
+		if ( accessor.normalized ) {
+
+			const scale = getNormalizedComponentScale( outputArray.constructor );
+			const scaled = new Float32Array( outputArray.length );
+
+			for ( let j = 0, jl = outputArray.length; j < jl; j ++ ) {
+
+				scaled[ j ] = outputArray[ j ] * scale;
+
+			}
+
+			outputArray = scaled;
+
+		}
+
+		return outputArray;
+
+	}
+
+	_createCubicSplineTrackInterpolant( track ) {
+
+		track.createInterpolant = function InterpolantFactoryMethodGLTFCubicSpline( result ) {
+
+			// A CUBICSPLINE keyframe in glTF has three output values for each input value,
+			// representing inTangent, splineVertex, and outTangent. As a result, track.getValueSize()
+			// must be divided by three to get the interpolant's sampleSize argument.
+
+			const interpolantType = ( this instanceof QuaternionKeyframeTrack ) ? GLTFCubicSplineQuaternionInterpolant : GLTFCubicSplineInterpolant;
+
+			return new interpolantType( this.times, this.values, this.getValueSize() / 3, result );
+
+		};
+
+		// Mark as CUBICSPLINE. `track.getInterpolation()` doesn't support custom interpolants.
+		track.createInterpolant.isInterpolantFactoryMethodGLTFCubicSpline = true;
+
+	}
+
+}
+
+/**
+ * @param {BufferGeometry} geometry
+ * @param {GLTF.Primitive} primitiveDef
+ * @param {GLTFParser} parser
+ */
+function computeBounds( geometry, primitiveDef, parser ) {
+
+	const attributes = primitiveDef.attributes;
+
+	const box = new Box3();
+
+	if ( attributes.POSITION !== undefined ) {
+
+		const accessor = parser.json.accessors[ attributes.POSITION ];
+
+		const min = accessor.min;
+		const max = accessor.max;
+
+		// glTF requires 'min' and 'max', but VRM (which extends glTF) currently ignores that requirement.
+
+		if ( min !== undefined && max !== undefined ) {
+
+			box.set(
+				new Vector3( min[ 0 ], min[ 1 ], min[ 2 ] ),
+				new Vector3( max[ 0 ], max[ 1 ], max[ 2 ] )
+			);
+
+			if ( accessor.normalized ) {
+
+				const boxScale = getNormalizedComponentScale( WEBGL_COMPONENT_TYPES[ accessor.componentType ] );
+				box.min.multiplyScalar( boxScale );
+				box.max.multiplyScalar( boxScale );
+
+			}
+
+		} else {
+
+			console.warn( 'THREE.GLTFLoader: Missing min/max properties for accessor POSITION.' );
+
+			return;
+
+		}
+
+	} else {
+
+		return;
+
+	}
+
+	const targets = primitiveDef.targets;
+
+	if ( targets !== undefined ) {
+
+		const maxDisplacement = new Vector3();
+		const vector = new Vector3();
+
+		for ( let i = 0, il = targets.length; i < il; i ++ ) {
+
+			const target = targets[ i ];
+
+			if ( target.POSITION !== undefined ) {
+
+				const accessor = parser.json.accessors[ target.POSITION ];
+				const min = accessor.min;
+				const max = accessor.max;
+
+				// glTF requires 'min' and 'max', but VRM (which extends glTF) currently ignores that requirement.
+
+				if ( min !== undefined && max !== undefined ) {
+
+					// we need to get max of absolute components because target weight is [-1,1]
+					vector.setX( Math.max( Math.abs( min[ 0 ] ), Math.abs( max[ 0 ] ) ) );
+					vector.setY( Math.max( Math.abs( min[ 1 ] ), Math.abs( max[ 1 ] ) ) );
+					vector.setZ( Math.max( Math.abs( min[ 2 ] ), Math.abs( max[ 2 ] ) ) );
+
+
+					if ( accessor.normalized ) {
+
+						const boxScale = getNormalizedComponentScale( WEBGL_COMPONENT_TYPES[ accessor.componentType ] );
+						vector.multiplyScalar( boxScale );
+
+					}
+
+					// Note: this assumes that the sum of all weights is at most 1. This isn't quite correct - it's more conservative
+					// to assume that each target can have a max weight of 1. However, for some use cases - notably, when morph targets
+					// are used to implement key-frame animations and as such only two are active at a time - this results in very large
+					// boxes. So for now we make a box that's sometimes a touch too small but is hopefully mostly of reasonable size.
+					maxDisplacement.max( vector );
+
+				} else {
+
+					console.warn( 'THREE.GLTFLoader: Missing min/max properties for accessor POSITION.' );
+
+				}
+
+			}
+
+		}
+
+		// As per comment above this box isn't conservative, but has a reasonable size for a very large number of morph targets.
+		box.expandByVector( maxDisplacement );
+
+	}
+
+	geometry.boundingBox = box;
+
+	const sphere = new Sphere();
+
+	box.getCenter( sphere.center );
+	sphere.radius = box.min.distanceTo( box.max ) / 2;
+
+	geometry.boundingSphere = sphere;
+
+}
+
+/**
+ * @param {BufferGeometry} geometry
+ * @param {GLTF.Primitive} primitiveDef
+ * @param {GLTFParser} parser
+ * @return {Promise<BufferGeometry>}
+ */
+function addPrimitiveAttributes( geometry, primitiveDef, parser ) {
+
+	const attributes = primitiveDef.attributes;
+
+	const pending = [];
+
+	function assignAttributeAccessor( accessorIndex, attributeName ) {
+
+		return parser.getDependency( 'accessor', accessorIndex )
+			.then( function ( accessor ) {
+
+				geometry.setAttribute( attributeName, accessor );
+
+			} );
+
+	}
+
+	for ( const gltfAttributeName in attributes ) {
+
+		const threeAttributeName = ATTRIBUTES[ gltfAttributeName ] || gltfAttributeName.toLowerCase();
+
+		// Skip attributes already provided by e.g. Draco extension.
+		if ( threeAttributeName in geometry.attributes ) continue;
+
+		pending.push( assignAttributeAccessor( attributes[ gltfAttributeName ], threeAttributeName ) );
+
+	}
+
+	if ( primitiveDef.indices !== undefined && ! geometry.index ) {
+
+		const accessor = parser.getDependency( 'accessor', primitiveDef.indices ).then( function ( accessor ) {
+
+			geometry.setIndex( accessor );
+
+		} );
+
+		pending.push( accessor );
+
+	}
+
+	if ( ColorManagement.workingColorSpace !== LinearSRGBColorSpace && 'COLOR_0' in attributes ) {
+
+		console.warn( `THREE.GLTFLoader: Converting vertex colors from "srgb-linear" to "${ColorManagement.workingColorSpace}" not supported.` );
+
+	}
+
+	assignExtrasToUserData( geometry, primitiveDef );
+
+	computeBounds( geometry, primitiveDef, parser );
+
+	return Promise.all( pending ).then( function () {
+
+		return primitiveDef.targets !== undefined
+			? addMorphTargets( geometry, primitiveDef.targets, parser )
+			: geometry;
+
+	} );
+
+}
+
+export { GLTFLoader };

nicegui/elements/scene.js

@@ -4,6 +4,7 @@ import { CSS3DRenderer, CSS3DObject } from "CSS3DRenderer";
 import { DragControls } from "DragControls";
 import { OrbitControls } from "OrbitControls";
 import { STLLoader } from "STLLoader";
+import { GLTFLoader } from "GLTFLoader";
 
 function texture_geometry(coords) {
   const geometry = new THREE.BufferGeometry();
@@ -178,6 +179,7 @@ export default {
 
     this.texture_loader = new THREE.TextureLoader();
     this.stl_loader = new STLLoader();
+    this.gltf_loader = new GLTFLoader();
 
     const connectInterval = setInterval(() => {
       if (window.socket.id === undefined) return;
@@ -242,6 +244,19 @@ export default {
         geometry.setAttribute("color", new THREE.Float32BufferAttribute(args[1].flat(), 3));
         const material = new THREE.PointsMaterial({ size: args[2], vertexColors: true });
         mesh = new THREE.Points(geometry, material);
+      } else if (type == "gltf") {
+        const url = args[0];
+        mesh = new THREE.Group();
+        this.gltf_loader.load(
+          url,
+          (gltf) => {
+            mesh.add(gltf.scene);
+          },
+          undefined,
+          (error) => {
+            console.error(error);
+          }
+        );
       } else {
         let geometry;
         const wireframe = args.pop();

nicegui/elements/scene.py

@@ -40,6 +40,8 @@ class Scene(Element,
                 'lib/three/modules/DragControls.js',
                 'lib/three/modules/OrbitControls.js',
                 'lib/three/modules/STLLoader.js',
+                'lib/three/modules/GLTFLoader.js',
+                'lib/three/modules/BufferGeometryUtils.js',
             ]):
     # pylint: disable=import-outside-toplevel
     from .scene_objects import Box as box
@@ -54,6 +56,7 @@ class Scene(Element,
     from .scene_objects import Sphere as sphere
     from .scene_objects import SpotLight as spot_light
     from .scene_objects import Stl as stl
+    from .scene_objects import Gltf as gltf
     from .scene_objects import Text as text
     from .scene_objects import Text3d as text3d
     from .scene_objects import Texture as texture

nicegui/elements/scene_objects.py

@@ -175,6 +175,20 @@ class Stl(Object3D):
         super().__init__('stl', url, wireframe)
 
 
+class Gltf(Object3D):
+
+    def __init__(self,
+                 url: str,
+                 ) -> None:
+        """GLTF
+
+        This element is used to create a mesh from an glTF file.
+
+        :param url: URL of the glTF file
+        """
+        super().__init__('gltf', url)
+
+
 class Line(Object3D):
 
     def __init__(self,

website/documentation/content/scene_documentation.py

@@ -25,6 +25,9 @@ def main_demo() -> None:
         teapot = 'https://upload.wikimedia.org/wikipedia/commons/9/93/Utah_teapot_(solid).stl'
         scene.stl(teapot).scale(0.2).move(-3, 4)
 
+        avocado = 'https://raw.githubusercontent.com/KhronosGroup/glTF-Sample-Assets/main/Models/Avocado/glTF-Binary/Avocado.glb'
+        scene.gltf(avocado).scale(40).move(-6, 0)
+
         scene.text('2D', 'background: rgba(0, 0, 0, 0.2); border-radius: 5px; padding: 5px').move(z=2)
         scene.text3d('3D', 'background: rgba(0, 0, 0, 0.2); border-radius: 5px; padding: 5px').move(y=-2).scale(.05)