// import {
// 	AnimationClip,
// 	Bone,
// 	Box3,
// 	BufferAttribute,
// 	BufferGeometry,
// 	CanvasTexture,
// 	ClampToEdgeWrapping,
// 	Color,
// 	DirectionalLight,
// 	DoubleSide,
// 	FileLoader,
// 	FrontSide,
// 	Group,
// 	ImageBitmapLoader,
// 	InterleavedBuffer,
// 	InterleavedBufferAttribute,
// 	Interpolant,
// 	InterpolateDiscrete,
// 	InterpolateLinear,
// 	Line,
// 	LineBasicMaterial,
// 	LineLoop,
// 	LineSegments,
// 	LinearFilter,
// 	LinearMipmapLinearFilter,
// 	LinearMipmapNearestFilter,
// 	Loader,
// 	LoaderUtils,
// 	Material,
// 	MathUtils,
// 	Matrix4,
// 	Mesh,
// 	MeshBasicMaterial,
// 	MeshPhysicalMaterial,
// 	MeshStandardMaterial,
// 	MirroredRepeatWrapping,
// 	NearestFilter,
// 	NearestMipmapLinearFilter,
// 	NearestMipmapNearestFilter,
// 	NumberKeyframeTrack,
// 	Object3D,
// 	OrthographicCamera,
// 	PerspectiveCamera,
// 	PointLight,
// 	Points,
// 	PointsMaterial,
// 	PropertyBinding,
// 	QuaternionKeyframeTrack,
// 	RGBFormat,
// 	RepeatWrapping,
// 	Skeleton,
// 	SkinnedMesh,
// 	Sphere,
// 	SpotLight,
// 	TangentSpaceNormalMap,
// 	TextureLoader,
// 	TriangleFanDrawMode,
// 	TriangleStripDrawMode,
// 	Vector2,
// 	Vector3,
// 	VectorKeyframeTrack,
// 	sRGBEncoding
// } from "../../../build/three.module.js";

// var GLTFLoader = ( function () {

// 	function GLTFLoader( manager ) {

// 		Loader.call( this, manager );

// 		this.dracoLoader = null;
// 		this.ddsLoader = null;
// 		this.ktx2Loader = 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 GLTFMaterialsTransmissionExtension( parser );

// 		} );

// 		this.register( function ( parser ) {

// 			return new GLTFLightsExtension( parser );

// 		} );

// 	}

// 	GLTFLoader.prototype = Object.assign( Object.create( Loader.prototype ), {

// 		constructor: GLTFLoader,

// 		load: function ( url, onLoad, onProgress, onError ) {

// 			var scope = this;

// 			var resourcePath;

// 			if ( this.resourcePath !== '' ) {

// 				resourcePath = this.resourcePath;

// 			} else if ( this.path !== '' ) {

// 				resourcePath = 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 );

// 			var _onError = function ( e ) {

// 				if ( onError ) {

// 					onError( e );

// 				} else {

// 					console.error( e );

// 				}

// 				scope.manager.itemError( url );
// 				scope.manager.itemEnd( url );

// 			};

// 			var 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: function ( dracoLoader ) {

// 			this.dracoLoader = dracoLoader;
// 			return this;

// 		},

// 		setDDSLoader: function ( ddsLoader ) {

// 			this.ddsLoader = ddsLoader;
// 			return this;

// 		},

// 		setKTX2Loader: function ( ktx2Loader ) {

// 			this.ktx2Loader = ktx2Loader;
// 			return this;

// 		},

// 		register: function ( callback ) {

// 			if ( this.pluginCallbacks.indexOf( callback ) === - 1 ) {

// 				this.pluginCallbacks.push( callback );

// 			}

// 			return this;

// 		},

// 		unregister: function ( callback ) {

// 			if ( this.pluginCallbacks.indexOf( callback ) !== - 1 ) {

// 				this.pluginCallbacks.splice( this.pluginCallbacks.indexOf( callback ), 1 );

// 			}

// 			return this;

// 		},

// 		parse: function ( data, path, onLoad, onError ) {

// 			var content;
// 			var extensions = {};
// 			var plugins = {};

// 			if ( typeof data === 'string' ) {

// 				content = data;

// 			} else {

// 				var magic = LoaderUtils.decodeText( 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;

// 					}

// 					content = extensions[ EXTENSIONS.KHR_BINARY_GLTF ].content;

// 				} else {

// 					content = LoaderUtils.decodeText( new Uint8Array( data ) );

// 				}

// 			}

// 			var json = JSON.parse( content );

// 			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;

// 			}

// 			var parser = new GLTFParser( json, {

// 				path: path || this.resourcePath || '',
// 				crossOrigin: this.crossOrigin,
// 				manager: this.manager,
// 				ktx2Loader: this.ktx2Loader

// 			} );

// 			parser.fileLoader.setRequestHeader( this.requestHeader );

// 			for ( var i = 0; i < this.pluginCallbacks.length; i ++ ) {

// 				var plugin = this.pluginCallbacks[ i ]( parser );
// 				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 ( var i = 0; i < json.extensionsUsed.length; ++ i ) {

// 					var extensionName = json.extensionsUsed[ i ];
// 					var extensionsRequired = json.extensionsRequired || [];

// 					switch ( extensionName ) {

// 						case EXTENSIONS.KHR_MATERIALS_UNLIT:
// 							extensions[ extensionName ] = new GLTFMaterialsUnlitExtension();
// 							break;

// 						case EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS:
// 							extensions[ extensionName ] = new GLTFMaterialsPbrSpecularGlossinessExtension();
// 							break;

// 						case EXTENSIONS.KHR_DRACO_MESH_COMPRESSION:
// 							extensions[ extensionName ] = new GLTFDracoMeshCompressionExtension( json, this.dracoLoader );
// 							break;

// 						case EXTENSIONS.MSFT_TEXTURE_DDS:
// 							extensions[ extensionName ] = new GLTFTextureDDSExtension( this.ddsLoader );
// 							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 );

// 		}

// 	} );

// 	/* GLTFREGISTRY */

// 	function GLTFRegistry() {

// 		var 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 ***********/
// 	/*********************************/

// 	var 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_PBR_SPECULAR_GLOSSINESS: 'KHR_materials_pbrSpecularGlossiness',
// 		KHR_MATERIALS_TRANSMISSION: 'KHR_materials_transmission',
// 		KHR_MATERIALS_UNLIT: 'KHR_materials_unlit',
// 		KHR_TEXTURE_BASISU: 'KHR_texture_basisu',
// 		KHR_TEXTURE_TRANSFORM: 'KHR_texture_transform',
// 		KHR_MESH_QUANTIZATION: 'KHR_mesh_quantization',
// 		MSFT_TEXTURE_DDS: 'MSFT_texture_dds'
// 	};

// 	/**
// 	 * DDS Texture Extension
// 	 *
// 	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Vendor/MSFT_texture_dds
// 	 *
// 	 */
// 	function GLTFTextureDDSExtension( ddsLoader ) {

// 		if ( ! ddsLoader ) {

// 			throw new Error( 'THREE.GLTFLoader: Attempting to load .dds texture without importing DDSLoader' );

// 		}

// 		this.name = EXTENSIONS.MSFT_TEXTURE_DDS;
// 		this.ddsLoader = ddsLoader;

// 	}

// 	/**
// 	 * Punctual Lights Extension
// 	 *
// 	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_lights_punctual
// 	 */
// 	function GLTFLightsExtension( parser ) {

// 		this.parser = parser;
// 		this.name = EXTENSIONS.KHR_LIGHTS_PUNCTUAL;

// 		// Object3D instance caches
// 		this.cache = { refs: {}, uses: {} };

// 	}

// 	GLTFLightsExtension.prototype._markDefs = function () {

// 		var parser = this.parser;
// 		var nodeDefs = this.parser.json.nodes || [];

// 		for ( var nodeIndex = 0, nodeLength = nodeDefs.length; nodeIndex < nodeLength; nodeIndex ++ ) {

// 			var 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 );

// 			}

// 		}

// 	};

// 	GLTFLightsExtension.prototype._loadLight = function ( lightIndex ) {

// 		var parser = this.parser;
// 		var cacheKey = 'light:' + lightIndex;
// 		var dependency = parser.cache.get( cacheKey );

// 		if ( dependency ) return dependency;

// 		var json = parser.json;
// 		var extensions = ( json.extensions && json.extensions[ this.name ] ) || {};
// 		var lightDefs = extensions.lights || [];
// 		var lightDef = lightDefs[ lightIndex ];
// 		var lightNode;

// 		var color = new Color( 0xffffff );

// 		if ( lightDef.color !== undefined ) color.fromArray( lightDef.color );

// 		var 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;

// 		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;

// 	};

// 	GLTFLightsExtension.prototype.createNodeAttachment = function ( nodeIndex ) {

// 		var self = this;
// 		var parser = this.parser;
// 		var json = parser.json;
// 		var nodeDef = json.nodes[ nodeIndex ];
// 		var lightDef = ( nodeDef.extensions && nodeDef.extensions[ this.name ] ) || {};
// 		var 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
// 	 */
// 	function GLTFMaterialsUnlitExtension() {

// 		this.name = EXTENSIONS.KHR_MATERIALS_UNLIT;

// 	}

// 	GLTFMaterialsUnlitExtension.prototype.getMaterialType = function () {

// 		return MeshBasicMaterial;

// 	};

// 	GLTFMaterialsUnlitExtension.prototype.extendParams = function ( materialParams, materialDef, parser ) {

// 		var pending = [];

// 		materialParams.color = new Color( 1.0, 1.0, 1.0 );
// 		materialParams.opacity = 1.0;

// 		var metallicRoughness = materialDef.pbrMetallicRoughness;

// 		if ( metallicRoughness ) {

// 			if ( Array.isArray( metallicRoughness.baseColorFactor ) ) {

// 				var array = metallicRoughness.baseColorFactor;

// 				materialParams.color.fromArray( array );
// 				materialParams.opacity = array[ 3 ];

// 			}

// 			if ( metallicRoughness.baseColorTexture !== undefined ) {

// 				pending.push( parser.assignTexture( materialParams, 'map', metallicRoughness.baseColorTexture ) );

// 			}

// 		}

// 		return Promise.all( pending );

// 	};

// 	/**
// 	 * Clearcoat Materials Extension
// 	 *
// 	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_materials_clearcoat
// 	 */
// 	function GLTFMaterialsClearcoatExtension( parser ) {

// 		this.parser = parser;
// 		this.name = EXTENSIONS.KHR_MATERIALS_CLEARCOAT;

// 	}

// 	GLTFMaterialsClearcoatExtension.prototype.getMaterialType = function ( materialIndex ) {

// 		var parser = this.parser;
// 		var materialDef = parser.json.materials[ materialIndex ];

// 		if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) return null;

// 		return MeshPhysicalMaterial;

// 	};

// 	GLTFMaterialsClearcoatExtension.prototype.extendMaterialParams = function ( materialIndex, materialParams ) {

// 		var parser = this.parser;
// 		var materialDef = parser.json.materials[ materialIndex ];

// 		if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) {

// 			return Promise.resolve();

// 		}

// 		var pending = [];

// 		var 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 ) {

// 				var scale = extension.clearcoatNormalTexture.scale;

// 				materialParams.clearcoatNormalScale = new Vector2( scale, scale );

// 			}

// 		}

// 		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
// 	 */
// 	function GLTFMaterialsTransmissionExtension( parser ) {

// 		this.parser = parser;
// 		this.name = EXTENSIONS.KHR_MATERIALS_TRANSMISSION;

// 	}

// 	GLTFMaterialsTransmissionExtension.prototype.getMaterialType = function ( materialIndex ) {

// 		var parser = this.parser;
// 		var materialDef = parser.json.materials[ materialIndex ];

// 		if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) return null;

// 		return MeshPhysicalMaterial;

// 	};

// 	GLTFMaterialsTransmissionExtension.prototype.extendMaterialParams = function ( materialIndex, materialParams ) {

// 		var parser = this.parser;
// 		var materialDef = parser.json.materials[ materialIndex ];

// 		if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) {

// 			return Promise.resolve();

// 		}

// 		var pending = [];

// 		var 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 );

// 	};

// 	/**
// 	 * BasisU Texture Extension
// 	 *
// 	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_texture_basisu
// 	 * (draft PR https://github.com/KhronosGroup/glTF/pull/1751)
// 	 */
// 	function GLTFTextureBasisUExtension( parser ) {

// 		this.parser = parser;
// 		this.name = EXTENSIONS.KHR_TEXTURE_BASISU;

// 	}

// 	GLTFTextureBasisUExtension.prototype.loadTexture = function ( textureIndex ) {

// 		var parser = this.parser;
// 		var json = parser.json;

// 		var textureDef = json.textures[ textureIndex ];

// 		if ( ! textureDef.extensions || ! textureDef.extensions[ this.name ] ) {

// 			return null;

// 		}

// 		var extension = textureDef.extensions[ this.name ];
// 		var source = json.images[ extension.source ];
// 		var loader = parser.options.ktx2Loader;

// 		if ( ! loader ) {

// 			throw new Error( 'THREE.GLTFLoader: setKTX2Loader must be called before loading KTX2 textures' );

// 		}

// 		return parser.loadTextureImage( textureIndex, source, loader );

// 	};

// 	/* BINARY EXTENSION */
// 	var BINARY_EXTENSION_HEADER_MAGIC = 'glTF';
// 	var BINARY_EXTENSION_HEADER_LENGTH = 12;
// 	var BINARY_EXTENSION_CHUNK_TYPES = { JSON: 0x4E4F534A, BIN: 0x004E4942 };

// 	function GLTFBinaryExtension( data ) {

// 		this.name = EXTENSIONS.KHR_BINARY_GLTF;
// 		this.content = null;
// 		this.body = null;

// 		var headerView = new DataView( data, 0, BINARY_EXTENSION_HEADER_LENGTH );

// 		this.header = {
// 			magic: LoaderUtils.decodeText( 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.' );

// 		}

// 		var chunkView = new DataView( data, BINARY_EXTENSION_HEADER_LENGTH );
// 		var chunkIndex = 0;

// 		while ( chunkIndex < chunkView.byteLength ) {

// 			var chunkLength = chunkView.getUint32( chunkIndex, true );
// 			chunkIndex += 4;

// 			var chunkType = chunkView.getUint32( chunkIndex, true );
// 			chunkIndex += 4;

// 			if ( chunkType === BINARY_EXTENSION_CHUNK_TYPES.JSON ) {

// 				var contentArray = new Uint8Array( data, BINARY_EXTENSION_HEADER_LENGTH + chunkIndex, chunkLength );
// 				this.content = LoaderUtils.decodeText( contentArray );

// 			} else if ( chunkType === BINARY_EXTENSION_CHUNK_TYPES.BIN ) {

// 				var 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
// 	 */
// 	function GLTFDracoMeshCompressionExtension( 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();

// 	}

// 	GLTFDracoMeshCompressionExtension.prototype.decodePrimitive = function ( primitive, parser ) {

// 		var json = this.json;
// 		var dracoLoader = this.dracoLoader;
// 		var bufferViewIndex = primitive.extensions[ this.name ].bufferView;
// 		var gltfAttributeMap = primitive.extensions[ this.name ].attributes;
// 		var threeAttributeMap = {};
// 		var attributeNormalizedMap = {};
// 		var attributeTypeMap = {};

// 		for ( var attributeName in gltfAttributeMap ) {

// 			var threeAttributeName = ATTRIBUTES[ attributeName ] || attributeName.toLowerCase();

// 			threeAttributeMap[ threeAttributeName ] = gltfAttributeMap[ attributeName ];

// 		}

// 		for ( attributeName in primitive.attributes ) {

// 			var threeAttributeName = ATTRIBUTES[ attributeName ] || attributeName.toLowerCase();

// 			if ( gltfAttributeMap[ attributeName ] !== undefined ) {

// 				var accessorDef = json.accessors[ primitive.attributes[ attributeName ] ];
// 				var componentType = WEBGL_COMPONENT_TYPES[ accessorDef.componentType ];

// 				attributeTypeMap[ threeAttributeName ] = componentType;
// 				attributeNormalizedMap[ threeAttributeName ] = accessorDef.normalized === true;

// 			}

// 		}

// 		return parser.getDependency( 'bufferView', bufferViewIndex ).then( function ( bufferView ) {

// 			return new Promise( function ( resolve ) {

// 				dracoLoader.decodeDracoFile( bufferView, function ( geometry ) {

// 					for ( var attributeName in geometry.attributes ) {

// 						var attribute = geometry.attributes[ attributeName ];
// 						var normalized = attributeNormalizedMap[ attributeName ];

// 						if ( normalized !== undefined ) attribute.normalized = normalized;

// 					}

// 					resolve( geometry );

// 				}, threeAttributeMap, attributeTypeMap );

// 			} );

// 		} );

// 	};

// 	/**
// 	 * Texture Transform Extension
// 	 *
// 	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_texture_transform
// 	 */
// 	function GLTFTextureTransformExtension() {

// 		this.name = EXTENSIONS.KHR_TEXTURE_TRANSFORM;

// 	}

// 	GLTFTextureTransformExtension.prototype.extendTexture = function ( texture, transform ) {

// 		texture = texture.clone();

// 		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 );

// 		}

// 		if ( transform.texCoord !== undefined ) {

// 			console.warn( 'THREE.GLTFLoader: Custom UV sets in "' + this.name + '" extension not yet supported.' );

// 		}

// 		texture.needsUpdate = true;

// 		return texture;

// 	};

// 	/**
// 	 * Specular-Glossiness Extension
// 	 *
// 	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_materials_pbrSpecularGlossiness
// 	 */

// 	/**
// 	 * A sub class of StandardMaterial with some of the functionality
// 	 * changed via the `onBeforeCompile` callback
// 	 * @pailhead
// 	 */

// 	function GLTFMeshStandardSGMaterial( params ) {

// 		MeshStandardMaterial.call( this );

// 		this.isGLTFSpecularGlossinessMaterial = true;

// 		//various chunks that need replacing
// 		var specularMapParsFragmentChunk = [
// 			'#ifdef USE_SPECULARMAP',
// 			'	uniform sampler2D specularMap;',
// 			'#endif'
// 		].join( '\n' );

// 		var glossinessMapParsFragmentChunk = [
// 			'#ifdef USE_GLOSSINESSMAP',
// 			'	uniform sampler2D glossinessMap;',
// 			'#endif'
// 		].join( '\n' );

// 		var specularMapFragmentChunk = [
// 			'vec3 specularFactor = specular;',
// 			'#ifdef USE_SPECULARMAP',
// 			'	vec4 texelSpecular = texture2D( specularMap, vUv );',
// 			'	texelSpecular = sRGBToLinear( texelSpecular );',
// 			'	// reads channel RGB, compatible with a glTF Specular-Glossiness (RGBA) texture',
// 			'	specularFactor *= texelSpecular.rgb;',
// 			'#endif'
// 		].join( '\n' );

// 		var glossinessMapFragmentChunk = [
// 			'float glossinessFactor = glossiness;',
// 			'#ifdef USE_GLOSSINESSMAP',
// 			'	vec4 texelGlossiness = texture2D( glossinessMap, vUv );',
// 			'	// reads channel A, compatible with a glTF Specular-Glossiness (RGBA) texture',
// 			'	glossinessFactor *= texelGlossiness.a;',
// 			'#endif'
// 		].join( '\n' );

// 		var lightPhysicalFragmentChunk = [
// 			'PhysicalMaterial material;',
// 			'material.diffuseColor = diffuseColor.rgb * ( 1. - max( specularFactor.r, max( specularFactor.g, specularFactor.b ) ) );',
// 			'vec3 dxy = max( abs( dFdx( geometryNormal ) ), abs( dFdy( geometryNormal ) ) );',
// 			'float geometryRoughness = max( max( dxy.x, dxy.y ), dxy.z );',
// 			'material.specularRoughness = max( 1.0 - glossinessFactor, 0.0525 ); // 0.0525 corresponds to the base mip of a 256 cubemap.',
// 			'material.specularRoughness += geometryRoughness;',
// 			'material.specularRoughness = min( material.specularRoughness, 1.0 );',
// 			'material.specularColor = specularFactor;',
// 		].join( '\n' );

// 		var uniforms = {
// 			specular: { value: new Color().setHex( 0xffffff ) },
// 			glossiness: { value: 1 },
// 			specularMap: { value: null },
// 			glossinessMap: { value: null }
// 		};

// 		this._extraUniforms = uniforms;

// 		this.onBeforeCompile = function ( shader ) {

// 			for ( var uniformName in uniforms ) {

// 				shader.uniforms[ uniformName ] = uniforms[ uniformName ];

// 			}

// 			shader.fragmentShader = shader.fragmentShader
// 				.replace( 'uniform float roughness;', 'uniform vec3 specular;' )
// 				.replace( 'uniform float metalness;', 'uniform float glossiness;' )
// 				.replace( '#include <roughnessmap_pars_fragment>', specularMapParsFragmentChunk )
// 				.replace( '#include <metalnessmap_pars_fragment>', glossinessMapParsFragmentChunk )
// 				.replace( '#include <roughnessmap_fragment>', specularMapFragmentChunk )
// 				.replace( '#include <metalnessmap_fragment>', glossinessMapFragmentChunk )
// 				.replace( '#include <lights_physical_fragment>', lightPhysicalFragmentChunk );

// 		};

// 		Object.defineProperties( this, {

// 			specular: {
// 				get: function () {

// 					return uniforms.specular.value;

// 				},
// 				set: function ( v ) {

// 					uniforms.specular.value = v;

// 				}
// 			},

// 			specularMap: {
// 				get: function () {

// 					return uniforms.specularMap.value;

// 				},
// 				set: function ( v ) {

// 					uniforms.specularMap.value = v;

// 					if ( v ) {

// 						this.defines.USE_SPECULARMAP = ''; // USE_UV is set by the renderer for specular maps

// 					} else {

// 						delete this.defines.USE_SPECULARMAP;

// 					}

// 				}
// 			},

// 			glossiness: {
// 				get: function () {

// 					return uniforms.glossiness.value;

// 				},
// 				set: function ( v ) {

// 					uniforms.glossiness.value = v;

// 				}
// 			},

// 			glossinessMap: {
// 				get: function () {

// 					return uniforms.glossinessMap.value;

// 				},
// 				set: function ( v ) {

// 					uniforms.glossinessMap.value = v;

// 					if ( v ) {

// 						this.defines.USE_GLOSSINESSMAP = '';
// 						this.defines.USE_UV = '';

// 					} else {

// 						delete this.defines.USE_GLOSSINESSMAP;
// 						delete this.defines.USE_UV;

// 					}

// 				}
// 			}

// 		} );

// 		delete this.metalness;
// 		delete this.roughness;
// 		delete this.metalnessMap;
// 		delete this.roughnessMap;

// 		this.setValues( params );

// 	}

// 	GLTFMeshStandardSGMaterial.prototype = Object.create( MeshStandardMaterial.prototype );
// 	GLTFMeshStandardSGMaterial.prototype.constructor = GLTFMeshStandardSGMaterial;

// 	GLTFMeshStandardSGMaterial.prototype.copy = function ( source ) {

// 		MeshStandardMaterial.prototype.copy.call( this, source );
// 		this.specularMap = source.specularMap;
// 		this.specular.copy( source.specular );
// 		this.glossinessMap = source.glossinessMap;
// 		this.glossiness = source.glossiness;
// 		delete this.metalness;
// 		delete this.roughness;
// 		delete this.metalnessMap;
// 		delete this.roughnessMap;
// 		return this;

// 	};

// 	function GLTFMaterialsPbrSpecularGlossinessExtension() {

// 		return {

// 			name: EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS,

// 			specularGlossinessParams: [
// 				'color',
// 				'map',
// 				'lightMap',
// 				'lightMapIntensity',
// 				'aoMap',
// 				'aoMapIntensity',
// 				'emissive',
// 				'emissiveIntensity',
// 				'emissiveMap',
// 				'bumpMap',
// 				'bumpScale',
// 				'normalMap',
// 				'normalMapType',
// 				'displacementMap',
// 				'displacementScale',
// 				'displacementBias',
// 				'specularMap',
// 				'specular',
// 				'glossinessMap',
// 				'glossiness',
// 				'alphaMap',
// 				'envMap',
// 				'envMapIntensity',
// 				'refractionRatio',
// 			],

// 			getMaterialType: function () {

// 				return GLTFMeshStandardSGMaterial;

// 			},

// 			extendParams: function ( materialParams, materialDef, parser ) {

// 				var pbrSpecularGlossiness = materialDef.extensions[ this.name ];

// 				materialParams.color = new Color( 1.0, 1.0, 1.0 );
// 				materialParams.opacity = 1.0;

// 				var pending = [];

// 				if ( Array.isArray( pbrSpecularGlossiness.diffuseFactor ) ) {

// 					var array = pbrSpecularGlossiness.diffuseFactor;

// 					materialParams.color.fromArray( array );
// 					materialParams.opacity = array[ 3 ];

// 				}

// 				if ( pbrSpecularGlossiness.diffuseTexture !== undefined ) {

// 					pending.push( parser.assignTexture( materialParams, 'map', pbrSpecularGlossiness.diffuseTexture ) );

// 				}

// 				materialParams.emissive = new Color( 0.0, 0.0, 0.0 );
// 				materialParams.glossiness = pbrSpecularGlossiness.glossinessFactor !== undefined ? pbrSpecularGlossiness.glossinessFactor : 1.0;
// 				materialParams.specular = new Color( 1.0, 1.0, 1.0 );

// 				if ( Array.isArray( pbrSpecularGlossiness.specularFactor ) ) {

// 					materialParams.specular.fromArray( pbrSpecularGlossiness.specularFactor );

// 				}

// 				if ( pbrSpecularGlossiness.specularGlossinessTexture !== undefined ) {

// 					var specGlossMapDef = pbrSpecularGlossiness.specularGlossinessTexture;
// 					pending.push( parser.assignTexture( materialParams, 'glossinessMap', specGlossMapDef ) );
// 					pending.push( parser.assignTexture( materialParams, 'specularMap', specGlossMapDef ) );

// 				}

// 				return Promise.all( pending );

// 			},

// 			createMaterial: function ( materialParams ) {

// 				var material = new GLTFMeshStandardSGMaterial( materialParams );
// 				material.fog = true;

// 				material.color = materialParams.color;

// 				material.map = materialParams.map === undefined ? null : materialParams.map;

// 				material.lightMap = null;
// 				material.lightMapIntensity = 1.0;

// 				material.aoMap = materialParams.aoMap === undefined ? null : materialParams.aoMap;
// 				material.aoMapIntensity = 1.0;

// 				material.emissive = materialParams.emissive;
// 				material.emissiveIntensity = 1.0;
// 				material.emissiveMap = materialParams.emissiveMap === undefined ? null : materialParams.emissiveMap;

// 				material.bumpMap = materialParams.bumpMap === undefined ? null : materialParams.bumpMap;
// 				material.bumpScale = 1;

// 				material.normalMap = materialParams.normalMap === undefined ? null : materialParams.normalMap;
// 				material.normalMapType = TangentSpaceNormalMap;

// 				if ( materialParams.normalScale ) material.normalScale = materialParams.normalScale;

// 				material.displacementMap = null;
// 				material.displacementScale = 1;
// 				material.displacementBias = 0;

// 				material.specularMap = materialParams.specularMap === undefined ? null : materialParams.specularMap;
// 				material.specular = materialParams.specular;

// 				material.glossinessMap = materialParams.glossinessMap === undefined ? null : materialParams.glossinessMap;
// 				material.glossiness = materialParams.glossiness;

// 				material.alphaMap = null;

// 				material.envMap = materialParams.envMap === undefined ? null : materialParams.envMap;
// 				material.envMapIntensity = 1.0;

// 				material.refractionRatio = 0.98;

// 				return material;

// 			},

// 		};

// 	}

// 	/**
// 	 * Mesh Quantization Extension
// 	 *
// 	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_mesh_quantization
// 	 */
// 	function GLTFMeshQuantizationExtension() {

// 		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
// 	function GLTFCubicSplineInterpolant( parameterPositions, sampleValues, sampleSize, resultBuffer ) {

// 		Interpolant.call( this, parameterPositions, sampleValues, sampleSize, resultBuffer );

// 	}

// 	GLTFCubicSplineInterpolant.prototype = Object.create( Interpolant.prototype );
// 	GLTFCubicSplineInterpolant.prototype.constructor = GLTFCubicSplineInterpolant;

// 	GLTFCubicSplineInterpolant.prototype.copySampleValue_ = function ( index ) {

// 		// Copies a sample value to the result buffer. See description of glTF
// 		// CUBICSPLINE values layout in interpolate_() function below.

// 		var result = this.resultBuffer,
// 			values = this.sampleValues,
// 			valueSize = this.valueSize,
// 			offset = index * valueSize * 3 + valueSize;

// 		for ( var i = 0; i !== valueSize; i ++ ) {

// 			result[ i ] = values[ offset + i ];

// 		}

// 		return result;

// 	};

// 	GLTFCubicSplineInterpolant.prototype.beforeStart_ = GLTFCubicSplineInterpolant.prototype.copySampleValue_;

// 	GLTFCubicSplineInterpolant.prototype.afterEnd_ = GLTFCubicSplineInterpolant.prototype.copySampleValue_;

// 	GLTFCubicSplineInterpolant.prototype.interpolate_ = function ( i1, t0, t, t1 ) {

// 		var result = this.resultBuffer;
// 		var values = this.sampleValues;
// 		var stride = this.valueSize;

// 		var stride2 = stride * 2;
// 		var stride3 = stride * 3;

// 		var td = t1 - t0;

// 		var p = ( t - t0 ) / td;
// 		var pp = p * p;
// 		var ppp = pp * p;

// 		var offset1 = i1 * stride3;
// 		var offset0 = offset1 - stride3;

// 		var s2 = - 2 * ppp + 3 * pp;
// 		var s3 = ppp - pp;
// 		var s0 = 1 - s2;
// 		var s1 = s3 - pp + p;

// 		// Layout of keyframe output values for CUBICSPLINE animations:
// 		//   [ inTangent_1, splineVertex_1, outTangent_1, inTangent_2, splineVertex_2, ... ]
// 		for ( var i = 0; i !== stride; i ++ ) {

// 			var p0 = values[ offset0 + i + stride ]; // splineVertex_k
// 			var m0 = values[ offset0 + i + stride2 ] * td; // outTangent_k * (t_k+1 - t_k)
// 			var p1 = values[ offset1 + i + stride ]; // splineVertex_k+1
// 			var 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;

// 	};

// 	/*********************************/
// 	/********** INTERNALS ************/
// 	/*********************************/

// 	/* CONSTANTS */

// 	var 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
// 	};

// 	var WEBGL_COMPONENT_TYPES = {
// 		5120: Int8Array,
// 		5121: Uint8Array,
// 		5122: Int16Array,
// 		5123: Uint16Array,
// 		5125: Uint32Array,
// 		5126: Float32Array
// 	};

// 	var WEBGL_FILTERS = {
// 		9728: NearestFilter,
// 		9729: LinearFilter,
// 		9984: NearestMipmapNearestFilter,
// 		9985: LinearMipmapNearestFilter,
// 		9986: NearestMipmapLinearFilter,
// 		9987: LinearMipmapLinearFilter
// 	};

// 	var WEBGL_WRAPPINGS = {
// 		33071: ClampToEdgeWrapping,
// 		33648: MirroredRepeatWrapping,
// 		10497: RepeatWrapping
// 	};

// 	var WEBGL_TYPE_SIZES = {
// 		'SCALAR': 1,
// 		'VEC2': 2,
// 		'VEC3': 3,
// 		'VEC4': 4,
// 		'MAT2': 4,
// 		'MAT3': 9,
// 		'MAT4': 16
// 	};

// 	var ATTRIBUTES = {
// 		POSITION: 'position',
// 		NORMAL: 'normal',
// 		TANGENT: 'tangent',
// 		TEXCOORD_0: 'uv',
// 		TEXCOORD_1: 'uv2',
// 		COLOR_0: 'color',
// 		WEIGHTS_0: 'skinWeight',
// 		JOINTS_0: 'skinIndex',
// 	};

// 	var PATH_PROPERTIES = {
// 		scale: 'scale',
// 		translation: 'position',
// 		rotation: 'quaternion',
// 		weights: 'morphTargetInfluences'
// 	};

// 	var 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
// 	};

// 	var ALPHA_MODES = {
// 		OPAQUE: 'OPAQUE',
// 		MASK: 'MASK',
// 		BLEND: 'BLEND'
// 	};

// 	/* UTILITY FUNCTIONS */

// 	function resolveURL( url, path ) {

// 		// Invalid URL
// 		if ( typeof url !== 'string' || url === '' ) return '';

// 		// Host Relative URL
// 		if ( /^https?:\/\//i.test( path ) && /^\//.test( url ) ) {

// 			path = path.replace( /(^https?:\/\/[^\/]+).*/i, '$1' );

// 		}

// 		// Absolute URL http://,https://,//
// 		if ( /^(https?:)?\/\//i.test( url ) ) return url;

// 		// Data URI
// 		if ( /^data:.*,.*$/i.test( url ) ) return url;

// 		// Blob URL
// 		if ( /^blob:.*$/i.test( url ) ) return url;

// 		// Relative URL
// 		return path + url;

// 	}

// 	/**
// 	 * 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 ( var 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 ) {

// 		var hasMorphPosition = false;
// 		var hasMorphNormal = false;

// 		for ( var i = 0, il = targets.length; i < il; i ++ ) {

// 			var target = targets[ i ];

// 			if ( target.POSITION !== undefined ) hasMorphPosition = true;
// 			if ( target.NORMAL !== undefined ) hasMorphNormal = true;

// 			if ( hasMorphPosition && hasMorphNormal ) break;

// 		}

// 		if ( ! hasMorphPosition && ! hasMorphNormal ) return Promise.resolve( geometry );

// 		var pendingPositionAccessors = [];
// 		var pendingNormalAccessors = [];

// 		for ( var i = 0, il = targets.length; i < il; i ++ ) {

// 			var target = targets[ i ];

// 			if ( hasMorphPosition ) {

// 				var pendingAccessor = target.POSITION !== undefined
// 					? parser.getDependency( 'accessor', target.POSITION )
// 					: geometry.attributes.position;

// 				pendingPositionAccessors.push( pendingAccessor );

// 			}

// 			if ( hasMorphNormal ) {

// 				var pendingAccessor = target.NORMAL !== undefined
// 					? parser.getDependency( 'accessor', target.NORMAL )
// 					: geometry.attributes.normal;

// 				pendingNormalAccessors.push( pendingAccessor );

// 			}

// 		}

// 		return Promise.all( [
// 			Promise.all( pendingPositionAccessors ),
// 			Promise.all( pendingNormalAccessors )
// 		] ).then( function ( accessors ) {

// 			var morphPositions = accessors[ 0 ];
// 			var morphNormals = accessors[ 1 ];

// 			if ( hasMorphPosition ) geometry.morphAttributes.position = morphPositions;
// 			if ( hasMorphNormal ) geometry.morphAttributes.normal = morphNormals;
// 			geometry.morphTargetsRelative = true;

// 			return geometry;

// 		} );

// 	}

// 	/**
// 	 * @param {Mesh} mesh
// 	 * @param {GLTF.Mesh} meshDef
// 	 */
// 	function updateMorphTargets( mesh, meshDef ) {

// 		mesh.updateMorphTargets();

// 		if ( meshDef.weights !== undefined ) {

// 			for ( var 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 ) ) {

// 			var targetNames = meshDef.extras.targetNames;

// 			if ( mesh.morphTargetInfluences.length === targetNames.length ) {

// 				mesh.morphTargetDictionary = {};

// 				for ( var 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 ) {

// 		var dracoExtension = primitiveDef.extensions && primitiveDef.extensions[ EXTENSIONS.KHR_DRACO_MESH_COMPRESSION ];
// 		var geometryKey;

// 		if ( dracoExtension ) {

// 			geometryKey = 'draco:' + dracoExtension.bufferView
// 				+ ':' + dracoExtension.indices
// 				+ ':' + createAttributesKey( dracoExtension.attributes );

// 		} else {

// 			geometryKey = primitiveDef.indices + ':' + createAttributesKey( primitiveDef.attributes ) + ':' + primitiveDef.mode;

// 		}

// 		return geometryKey;

// 	}

// 	function createAttributesKey( attributes ) {

// 		var attributesKey = '';

// 		var keys = Object.keys( attributes ).sort();

// 		for ( var i = 0, il = keys.length; i < il; i ++ ) {

// 			attributesKey += keys[ i ] + ':' + attributes[ keys[ i ] ] + ';';

// 		}

// 		return attributesKey;

// 	}

// 	/* GLTF PARSER */

// 	function GLTFParser( 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 = {};

// 		// Object3D instance caches
// 		this.meshCache = { refs: {}, uses: {} };
// 		this.cameraCache = { refs: {}, uses: {} };
// 		this.lightCache = { refs: {}, uses: {} };

// 		// 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.
// 		if ( typeof createImageBitmap !== 'undefined' && /Firefox/.test( navigator.userAgent ) === false ) {

// 			this.textureLoader = new ImageBitmapLoader( this.options.manager );

// 		} else {

// 			this.textureLoader = new TextureLoader( this.options.manager );

// 		}

// 		this.textureLoader.setCrossOrigin( this.options.crossOrigin );

// 		this.fileLoader = new FileLoader( this.options.manager );
// 		this.fileLoader.setResponseType( 'arraybuffer' );

// 		if ( this.options.crossOrigin === 'use-credentials' ) {

// 			this.fileLoader.setWithCredentials( true );

// 		}

// 	}

// 	GLTFParser.prototype.setExtensions = function ( extensions ) {

// 		this.extensions = extensions;

// 	};

// 	GLTFParser.prototype.setPlugins = function ( plugins ) {

// 		this.plugins = plugins;

// 	};

// 	GLTFParser.prototype.parse = function ( onLoad, onError ) {

// 		var parser = this;
// 		var json = this.json;
// 		var extensions = this.extensions;

// 		// Clear the loader cache
// 		this.cache.removeAll();

// 		// Mark the special nodes/meshes in json for efficient parse
// 		this._invokeAll( function ( ext ) {

// 			return ext._markDefs && ext._markDefs();

// 		} );

// 		Promise.all( [

// 			this.getDependencies( 'scene' ),
// 			this.getDependencies( 'animation' ),
// 			this.getDependencies( 'camera' ),

// 		] ).then( function ( dependencies ) {

// 			var 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 );

// 			onLoad( result );

// 		} ).catch( onError );

// 	};

// 	/**
// 	 * Marks the special nodes/meshes in json for efficient parse.
// 	 */
// 	GLTFParser.prototype._markDefs = function () {

// 		var nodeDefs = this.json.nodes || [];
// 		var skinDefs = this.json.skins || [];
// 		var 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 ( var skinIndex = 0, skinLength = skinDefs.length; skinIndex < skinLength; skinIndex ++ ) {

// 			var joints = skinDefs[ skinIndex ].joints;

// 			for ( var 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 ( var nodeIndex = 0, nodeLength = nodeDefs.length; nodeIndex < nodeLength; nodeIndex ++ ) {

// 			var 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.
// 	 */
// 	GLTFParser.prototype._addNodeRef = function ( 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. */
// 	GLTFParser.prototype._getNodeRef = function ( cache, index, object ) {

// 		if ( cache.refs[ index ] <= 1 ) return object;

// 		var ref = object.clone();

// 		ref.name += '_instance_' + ( cache.uses[ index ] ++ );

// 		return ref;

// 	};

// 	GLTFParser.prototype._invokeOne = function ( func ) {

// 		var extensions = Object.values( this.plugins );
// 		extensions.push( this );

// 		for ( var i = 0; i < extensions.length; i ++ ) {

// 			var result = func( extensions[ i ] );

// 			if ( result ) return result;

// 		}

// 	};

// 	GLTFParser.prototype._invokeAll = function ( func ) {

// 		var extensions = Object.values( this.plugins );
// 		extensions.unshift( this );

// 		var pending = [];

// 		for ( var i = 0; i < extensions.length; i ++ ) {

// 			var 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>}
// 	 */
// 	GLTFParser.prototype.getDependency = function ( type, index ) {

// 		var cacheKey = type + ':' + index;
// 		var dependency = this.cache.get( cacheKey );

// 		if ( ! dependency ) {

// 			switch ( type ) {

// 				case 'scene':
// 					dependency = this.loadScene( index );
// 					break;

// 				case 'node':
// 					dependency = this.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.loadAnimation( index );
// 					break;

// 				case 'camera':
// 					dependency = this.loadCamera( index );
// 					break;

// 				default:
// 					throw new Error( 'Unknown type: ' + type );

// 			}

// 			this.cache.add( cacheKey, dependency );

// 		}

// 		return dependency;

// 	};

// 	/**
// 	 * Requests all dependencies of the specified type asynchronously, with caching.
// 	 * @param {string} type
// 	 * @return {Promise<Array<Object>>}
// 	 */
// 	GLTFParser.prototype.getDependencies = function ( type ) {

// 		var dependencies = this.cache.get( type );

// 		if ( ! dependencies ) {

// 			var parser = this;
// 			var 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>}
// 	 */
// 	GLTFParser.prototype.loadBuffer = function ( bufferIndex ) {

// 		var bufferDef = this.json.buffers[ bufferIndex ];
// 		var 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 );

// 		}

// 		var options = this.options;

// 		return new Promise( function ( resolve, reject ) {

// 			loader.load( 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>}
// 	 */
// 	GLTFParser.prototype.loadBufferView = function ( bufferViewIndex ) {

// 		var bufferViewDef = this.json.bufferViews[ bufferViewIndex ];

// 		return this.getDependency( 'buffer', bufferViewDef.buffer ).then( function ( buffer ) {

// 			var byteLength = bufferViewDef.byteLength || 0;
// 			var 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>}
// 	 */
// 	GLTFParser.prototype.loadAccessor = function ( accessorIndex ) {

// 		var parser = this;
// 		var json = this.json;

// 		var accessorDef = this.json.accessors[ accessorIndex ];

// 		if ( accessorDef.bufferView === undefined && accessorDef.sparse === undefined ) {

// 			// Ignore empty accessors, which may be used to declare runtime
// 			// information about attributes coming from another source (e.g. Draco
// 			// compression extension).
// 			return Promise.resolve( null );

// 		}

// 		var 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 ) {

// 			var bufferView = bufferViews[ 0 ];

// 			var itemSize = WEBGL_TYPE_SIZES[ accessorDef.type ];
// 			var TypedArray = WEBGL_COMPONENT_TYPES[ accessorDef.componentType ];

// 			// For VEC3: itemSize is 3, elementBytes is 4, itemBytes is 12.
// 			var elementBytes = TypedArray.BYTES_PER_ELEMENT;
// 			var itemBytes = elementBytes * itemSize;
// 			var byteOffset = accessorDef.byteOffset || 0;
// 			var byteStride = accessorDef.bufferView !== undefined ? json.bufferViews[ accessorDef.bufferView ].byteStride : undefined;
// 			var normalized = accessorDef.normalized === true;
// 			var 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
// 				var ibSlice = Math.floor( byteOffset / byteStride );
// 				var ibCacheKey = 'InterleavedBuffer:' + accessorDef.bufferView + ':' + accessorDef.componentType + ':' + ibSlice + ':' + accessorDef.count;
// 				var 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 ) {

// 				var itemSizeIndices = WEBGL_TYPE_SIZES.SCALAR;
// 				var TypedArrayIndices = WEBGL_COMPONENT_TYPES[ accessorDef.sparse.indices.componentType ];

// 				var byteOffsetIndices = accessorDef.sparse.indices.byteOffset || 0;
// 				var byteOffsetValues = accessorDef.sparse.values.byteOffset || 0;

// 				var sparseIndices = new TypedArrayIndices( bufferViews[ 1 ], byteOffsetIndices, accessorDef.sparse.count * itemSizeIndices );
// 				var 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 ( var i = 0, il = sparseIndices.length; i < il; i ++ ) {

// 					var 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>}
// 	 */
// 	GLTFParser.prototype.loadTexture = function ( textureIndex ) {

// 		var parser = this;
// 		var json = this.json;
// 		var options = this.options;

// 		var textureDef = json.textures[ textureIndex ];

// 		var textureExtensions = textureDef.extensions || {};

// 		var source;

// 		if ( textureExtensions[ EXTENSIONS.MSFT_TEXTURE_DDS ] ) {

// 			source = json.images[ textureExtensions[ EXTENSIONS.MSFT_TEXTURE_DDS ].source ];

// 		} else {

// 			source = json.images[ textureDef.source ];

// 		}

// 		var loader;

// 		if ( source.uri ) {

// 			loader = options.manager.getHandler( source.uri );

// 		}

// 		if ( ! loader ) {

// 			loader = textureExtensions[ EXTENSIONS.MSFT_TEXTURE_DDS ]
// 				? parser.extensions[ EXTENSIONS.MSFT_TEXTURE_DDS ].ddsLoader
// 				: this.textureLoader;

// 		}

// 		return this.loadTextureImage( textureIndex, source, loader );

// 	};

// 	GLTFParser.prototype.loadTextureImage = function ( textureIndex, source, loader ) {

// 		var parser = this;
// 		var json = this.json;
// 		var options = this.options;

// 		var textureDef = json.textures[ textureIndex ];

// 		var URL = self.URL || self.webkitURL;

// 		var sourceURI = source.uri;
// 		var isObjectURL = false;
// 		var hasAlpha = true;

// 		if ( source.mimeType === 'image/jpeg' ) hasAlpha = false;

// 		if ( source.bufferView !== undefined ) {

// 			// Load binary image data from bufferView, if provided.

// 			sourceURI = parser.getDependency( 'bufferView', source.bufferView ).then( function ( bufferView ) {

// 				if ( source.mimeType === 'image/png' ) {

// 					// Inspect the PNG 'IHDR' chunk to determine whether the image could have an
// 					// alpha channel. This check is conservative — the image could have an alpha
// 					// channel with all values == 1, and the indexed type (colorType == 3) only
// 					// sometimes contains alpha.
// 					//
// 					// https://en.wikipedia.org/wiki/Portable_Network_Graphics#File_header
// 					var colorType = new DataView( bufferView, 25, 1 ).getUint8( 0, false );
// 					hasAlpha = colorType === 6 || colorType === 4 || colorType === 3;

// 				}

// 				isObjectURL = true;
// 				var blob = new Blob( [ bufferView ], { type: source.mimeType } );
// 				sourceURI = URL.createObjectURL( blob );
// 				return sourceURI;

// 			} );

// 		}

// 		return Promise.resolve( sourceURI ).then( function ( sourceURI ) {

// 			return new Promise( function ( resolve, reject ) {

// 				var onLoad = resolve;

// 				if ( loader.isImageBitmapLoader === true ) {

// 					onLoad = function ( imageBitmap ) {

// 						resolve( new CanvasTexture( imageBitmap ) );

// 					};

// 				}

// 				loader.load( resolveURL( sourceURI, options.path ), onLoad, undefined, reject );

// 			} );

// 		} ).then( function ( texture ) {

// 			// Clean up resources and configure Texture.

// 			if ( isObjectURL === true ) {

// 				URL.revokeObjectURL( sourceURI );

// 			}

// 			texture.flipY = false;

// 			if ( textureDef.name ) texture.name = textureDef.name;

// 			// When there is definitely no alpha channel in the texture, set RGBFormat to save space.
// 			if ( ! hasAlpha ) texture.format = RGBFormat;

// 			var samplers = json.samplers || {};
// 			var 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, {
// 				type: 'textures',
// 				index: textureIndex
// 			} );

// 			return texture;

// 		} );

// 	};

// 	/**
// 	 * Asynchronously assigns a texture to the given material parameters.
// 	 * @param {Object} materialParams
// 	 * @param {string} mapName
// 	 * @param {Object} mapDef
// 	 * @return {Promise}
// 	 */
// 	GLTFParser.prototype.assignTexture = function ( materialParams, mapName, mapDef ) {

// 		var parser = this;

// 		return this.getDependency( 'texture', mapDef.index ).then( function ( texture ) {

// 			// Materials sample aoMap from UV set 1 and other maps from UV set 0 - this can't be configured
// 			// However, we will copy UV set 0 to UV set 1 on demand for aoMap
// 			if ( mapDef.texCoord !== undefined && mapDef.texCoord != 0 && ! ( mapName === 'aoMap' && mapDef.texCoord == 1 ) ) {

// 				console.warn( 'THREE.GLTFLoader: Custom UV set ' + mapDef.texCoord + ' for texture ' + mapName + ' not yet supported.' );

// 			}

// 			if ( parser.extensions[ EXTENSIONS.KHR_TEXTURE_TRANSFORM ] ) {

// 				var transform = mapDef.extensions !== undefined ? mapDef.extensions[ EXTENSIONS.KHR_TEXTURE_TRANSFORM ] : undefined;

// 				if ( transform ) {

// 					var gltfReference = parser.associations.get( texture );
// 					texture = parser.extensions[ EXTENSIONS.KHR_TEXTURE_TRANSFORM ].extendTexture( texture, transform );
// 					parser.associations.set( texture, gltfReference );

// 				}

// 			}

// 			materialParams[ mapName ] = 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 accomodate 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.
// 	 */
// 	GLTFParser.prototype.assignFinalMaterial = function ( mesh ) {

// 		var geometry = mesh.geometry;
// 		var material = mesh.material;

// 		var useVertexTangents = geometry.attributes.tangent !== undefined;
// 		var useVertexColors = geometry.attributes.color !== undefined;
// 		var useFlatShading = geometry.attributes.normal === undefined;
// 		var useSkinning = mesh.isSkinnedMesh === true;
// 		var useMorphTargets = Object.keys( geometry.morphAttributes ).length > 0;
// 		var useMorphNormals = useMorphTargets && geometry.morphAttributes.normal !== undefined;

// 		if ( mesh.isPoints ) {

// 			var cacheKey = 'PointsMaterial:' + material.uuid;

// 			var 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 ) {

// 			var cacheKey = 'LineBasicMaterial:' + material.uuid;

// 			var lineMaterial = this.cache.get( cacheKey );

// 			if ( ! lineMaterial ) {

// 				lineMaterial = new LineBasicMaterial();
// 				Material.prototype.copy.call( lineMaterial, material );
// 				lineMaterial.color.copy( material.color );

// 				this.cache.add( cacheKey, lineMaterial );

// 			}

// 			material = lineMaterial;

// 		}

// 		// Clone the material if it will be modified
// 		if ( useVertexTangents || useVertexColors || useFlatShading || useSkinning || useMorphTargets ) {

// 			var cacheKey = 'ClonedMaterial:' + material.uuid + ':';

// 			if ( material.isGLTFSpecularGlossinessMaterial ) cacheKey += 'specular-glossiness:';
// 			if ( useSkinning ) cacheKey += 'skinning:';
// 			if ( useVertexTangents ) cacheKey += 'vertex-tangents:';
// 			if ( useVertexColors ) cacheKey += 'vertex-colors:';
// 			if ( useFlatShading ) cacheKey += 'flat-shading:';
// 			if ( useMorphTargets ) cacheKey += 'morph-targets:';
// 			if ( useMorphNormals ) cacheKey += 'morph-normals:';

// 			var cachedMaterial = this.cache.get( cacheKey );

// 			if ( ! cachedMaterial ) {

// 				cachedMaterial = material.clone();

// 				if ( useSkinning ) cachedMaterial.skinning = true;
// 				if ( useVertexTangents ) cachedMaterial.vertexTangents = true;
// 				if ( useVertexColors ) cachedMaterial.vertexColors = true;
// 				if ( useFlatShading ) cachedMaterial.flatShading = true;
// 				if ( useMorphTargets ) cachedMaterial.morphTargets = true;
// 				if ( useMorphNormals ) cachedMaterial.morphNormals = true;

// 				this.cache.add( cacheKey, cachedMaterial );

// 				this.associations.set( cachedMaterial, this.associations.get( material ) );

// 			}

// 			material = cachedMaterial;

// 		}

// 		// workarounds for mesh and geometry

// 		if ( material.aoMap && geometry.attributes.uv2 === undefined && geometry.attributes.uv !== undefined ) {

// 			geometry.setAttribute( 'uv2', geometry.attributes.uv );

// 		}

// 		// https://github.com/mrdoob/three.js/issues/11438#issuecomment-507003995
// 		if ( material.normalScale && ! useVertexTangents ) {

// 			material.normalScale.y = - material.normalScale.y;

// 		}

// 		if ( material.clearcoatNormalScale && ! useVertexTangents ) {

// 			material.clearcoatNormalScale.y = - material.clearcoatNormalScale.y;

// 		}

// 		mesh.material = material;

// 	};

// 	GLTFParser.prototype.getMaterialType = function ( /* materialIndex */ ) {

// 		return MeshStandardMaterial;

// 	};

// 	/**
// 	 * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#materials
// 	 * @param {number} materialIndex
// 	 * @return {Promise<Material>}
// 	 */
// 	GLTFParser.prototype.loadMaterial = function ( materialIndex ) {

// 		var parser = this;
// 		var json = this.json;
// 		var extensions = this.extensions;
// 		var materialDef = json.materials[ materialIndex ];

// 		var materialType;
// 		var materialParams = {};
// 		var materialExtensions = materialDef.extensions || {};

// 		var pending = [];

// 		if ( materialExtensions[ EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS ] ) {

// 			var sgExtension = extensions[ EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS ];
// 			materialType = sgExtension.getMaterialType();
// 			pending.push( sgExtension.extendParams( materialParams, materialDef, parser ) );

// 		} else if ( materialExtensions[ EXTENSIONS.KHR_MATERIALS_UNLIT ] ) {

// 			var 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

// 			var metallicRoughness = materialDef.pbrMetallicRoughness || {};

// 			materialParams.color = new Color( 1.0, 1.0, 1.0 );
// 			materialParams.opacity = 1.0;

// 			if ( Array.isArray( metallicRoughness.baseColorFactor ) ) {

// 				var array = metallicRoughness.baseColorFactor;

// 				materialParams.color.fromArray( array );
// 				materialParams.opacity = array[ 3 ];

// 			}

// 			if ( metallicRoughness.baseColorTexture !== undefined ) {

// 				pending.push( parser.assignTexture( materialParams, 'map', metallicRoughness.baseColorTexture ) );

// 			}

// 			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;

// 		}

// 		var 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 ) {

// 				materialParams.normalScale.set( materialDef.normalTexture.scale, materialDef.normalTexture.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 ) {

// 			materialParams.emissive = new Color().fromArray( materialDef.emissiveFactor );

// 		}

// 		if ( materialDef.emissiveTexture !== undefined && materialType !== MeshBasicMaterial ) {

// 			pending.push( parser.assignTexture( materialParams, 'emissiveMap', materialDef.emissiveTexture ) );

// 		}

// 		return Promise.all( pending ).then( function () {

// 			var material;

// 			if ( materialType === GLTFMeshStandardSGMaterial ) {

// 				material = extensions[ EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS ].createMaterial( materialParams );

// 			} else {

// 				material = new materialType( materialParams );

// 			}

// 			if ( materialDef.name ) material.name = materialDef.name;

// 			// baseColorTexture, emissiveTexture, and specularGlossinessTexture use sRGB encoding.
// 			if ( material.map ) material.map.encoding = sRGBEncoding;
// 			if ( material.emissiveMap ) material.emissiveMap.encoding = sRGBEncoding;

// 			assignExtrasToUserData( material, materialDef );

// 			parser.associations.set( material, { type: 'materials', index: materialIndex } );

// 			if ( materialDef.extensions ) addUnknownExtensionsToUserData( extensions, material, materialDef );

// 			return material;

// 		} );

// 	};

// 	/** When Object3D instances are targeted by animation, they need unique names. */
// 	GLTFParser.prototype.createUniqueName = function ( originalName ) {

// 		var name = PropertyBinding.sanitizeNodeName( originalName || '' );

// 		for ( var i = 1; this.nodeNamesUsed[ name ]; ++ i ) {

// 			name = originalName + '_' + i;

// 		}

// 		this.nodeNamesUsed[ name ] = true;

// 		return name;

// 	};

// 	/**
// 	 * @param {BufferGeometry} geometry
// 	 * @param {GLTF.Primitive} primitiveDef
// 	 * @param {GLTFParser} parser
// 	 */
// 	function computeBounds( geometry, primitiveDef, parser ) {

// 		var attributes = primitiveDef.attributes;

// 		var box = new Box3();

// 		if ( attributes.POSITION !== undefined ) {

// 			var accessor = parser.json.accessors[ attributes.POSITION ];

// 			var min = accessor.min;
// 			var 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 ] ) );

// 			} else {

// 				console.warn( 'THREE.GLTFLoader: Missing min/max properties for accessor POSITION.' );

// 				return;

// 			}

// 		} else {

// 			return;

// 		}

// 		var targets = primitiveDef.targets;

// 		if ( targets !== undefined ) {

// 			var maxDisplacement = new Vector3();
// 			var vector = new Vector3();

// 			for ( var i = 0, il = targets.length; i < il; i ++ ) {

// 				var target = targets[ i ];

// 				if ( target.POSITION !== undefined ) {

// 					var accessor = parser.json.accessors[ target.POSITION ];
// 					var min = accessor.min;
// 					var 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 ] ) ) );

// 						// 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;

// 		var 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 ) {

// 		var attributes = primitiveDef.attributes;

// 		var pending = [];

// 		function assignAttributeAccessor( accessorIndex, attributeName ) {

// 			return parser.getDependency( 'accessor', accessorIndex )
// 				.then( function ( accessor ) {

// 					geometry.setAttribute( attributeName, accessor );

// 				} );

// 		}

// 		for ( var gltfAttributeName in attributes ) {

// 			var 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 ) {

// 			var accessor = parser.getDependency( 'accessor', primitiveDef.indices ).then( function ( accessor ) {

// 				geometry.setIndex( accessor );

// 			} );

// 			pending.push( accessor );

// 		}

// 		assignExtrasToUserData( geometry, primitiveDef );

// 		computeBounds( geometry, primitiveDef, parser );

// 		return Promise.all( pending ).then( function () {

// 			return primitiveDef.targets !== undefined
// 				? addMorphTargets( geometry, primitiveDef.targets, parser )
// 				: geometry;

// 		} );

// 	}

// 	/**
// 	 * @param {BufferGeometry} geometry
// 	 * @param {Number} drawMode
// 	 * @return {BufferGeometry}
// 	 */
// 	function toTrianglesDrawMode( geometry, drawMode ) {

// 		var index = geometry.getIndex();

// 		// generate index if not present

// 		if ( index === null ) {

// 			var indices = [];

// 			var position = geometry.getAttribute( 'position' );

// 			if ( position !== undefined ) {

// 				for ( var i = 0; i < position.count; i ++ ) {

// 					indices.push( i );

// 				}

// 				geometry.setIndex( indices );
// 				index = geometry.getIndex();

// 			} else {

// 				console.error( 'THREE.GLTFLoader.toTrianglesDrawMode(): Undefined position attribute. Processing not possible.' );
// 				return geometry;

// 			}

// 		}

// 		//

// 		var numberOfTriangles = index.count - 2;
// 		var newIndices = [];

// 		if ( drawMode === TriangleFanDrawMode ) {

// 			// gl.TRIANGLE_FAN

// 			for ( var 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 ( var 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.GLTFLoader.toTrianglesDrawMode(): Unable to generate correct amount of triangles.' );

// 		}

// 		// build final geometry

// 		var newGeometry = geometry.clone();
// 		newGeometry.setIndex( newIndices );

// 		return newGeometry;

// 	}

// 	/**
// 	 * 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>>}
// 	 */
// 	GLTFParser.prototype.loadGeometries = function ( primitives ) {

// 		var parser = this;
// 		var extensions = this.extensions;
// 		var cache = this.primitiveCache;

// 		function createDracoPrimitive( primitive ) {

// 			return extensions[ EXTENSIONS.KHR_DRACO_MESH_COMPRESSION ]
// 				.decodePrimitive( primitive, parser )
// 				.then( function ( geometry ) {

// 					return addPrimitiveAttributes( geometry, primitive, parser );

// 				} );

// 		}

// 		var pending = [];

// 		for ( var i = 0, il = primitives.length; i < il; i ++ ) {

// 			var primitive = primitives[ i ];
// 			var cacheKey = createPrimitiveKey( primitive );

// 			// See if we've already created this geometry
// 			var cached = cache[ cacheKey ];

// 			if ( cached ) {

// 				// Use the cached geometry if it exists
// 				pending.push( cached.promise );

// 			} else {

// 				var 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>}
// 	 */
// 	GLTFParser.prototype.loadMesh = function ( meshIndex ) {

// 		var parser = this;
// 		var json = this.json;

// 		var meshDef = json.meshes[ meshIndex ];
// 		var primitives = meshDef.primitives;

// 		var pending = [];

// 		for ( var i = 0, il = primitives.length; i < il; i ++ ) {

// 			var 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 ) {

// 			var materials = results.slice( 0, results.length - 1 );
// 			var geometries = results[ results.length - 1 ];

// 			var meshes = [];

// 			for ( var i = 0, il = geometries.length; i < il; i ++ ) {

// 				var geometry = geometries[ i ];
// 				var primitive = primitives[ i ];

// 				// 1. create Mesh

// 				var mesh;

// 				var 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 && ! mesh.geometry.attributes.skinWeight.normalized ) {

// 						// we normalize floating point skin weight array to fix malformed assets (see #15319)
// 						// it's important to skip this for non-float32 data since normalizeSkinWeights assumes non-normalized inputs
// 						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 ) );

// 				if ( geometries.length > 1 ) mesh.name += '_' + i;

// 				assignExtrasToUserData( mesh, meshDef );

// 				parser.assignFinalMaterial( mesh );

// 				meshes.push( mesh );

// 			}

// 			if ( meshes.length === 1 ) {

// 				return meshes[ 0 ];

// 			}

// 			var group = new Group();

// 			for ( var 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>}
// 	 */
// 	GLTFParser.prototype.loadCamera = function ( cameraIndex ) {

// 		var camera;
// 		var cameraDef = this.json.cameras[ cameraIndex ];
// 		var 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<Object>}
// 	 */
// 	GLTFParser.prototype.loadSkin = function ( skinIndex ) {

// 		var skinDef = this.json.skins[ skinIndex ];

// 		var skinEntry = { joints: skinDef.joints };

// 		if ( skinDef.inverseBindMatrices === undefined ) {

// 			return Promise.resolve( skinEntry );

// 		}

// 		return this.getDependency( 'accessor', skinDef.inverseBindMatrices ).then( function ( accessor ) {

// 			skinEntry.inverseBindMatrices = accessor;

// 			return skinEntry;

// 		} );

// 	};

// 	/**
// 	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#animations
// 	 * @param {number} animationIndex
// 	 * @return {Promise<AnimationClip>}
// 	 */
// 	GLTFParser.prototype.loadAnimation = function ( animationIndex ) {

// 		var json = this.json;

// 		var animationDef = json.animations[ animationIndex ];

// 		var pendingNodes = [];
// 		var pendingInputAccessors = [];
// 		var pendingOutputAccessors = [];
// 		var pendingSamplers = [];
// 		var pendingTargets = [];

// 		for ( var i = 0, il = animationDef.channels.length; i < il; i ++ ) {

// 			var channel = animationDef.channels[ i ];
// 			var sampler = animationDef.samplers[ channel.sampler ];
// 			var target = channel.target;
// 			var name = target.node !== undefined ? target.node : target.id; // NOTE: target.id is deprecated.
// 			var input = animationDef.parameters !== undefined ? animationDef.parameters[ sampler.input ] : sampler.input;
// 			var output = animationDef.parameters !== undefined ? animationDef.parameters[ sampler.output ] : sampler.output;

// 			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 ) {

// 			var nodes = dependencies[ 0 ];
// 			var inputAccessors = dependencies[ 1 ];
// 			var outputAccessors = dependencies[ 2 ];
// 			var samplers = dependencies[ 3 ];
// 			var targets = dependencies[ 4 ];

// 			var tracks = [];

// 			for ( var i = 0, il = nodes.length; i < il; i ++ ) {

// 				var node = nodes[ i ];
// 				var inputAccessor = inputAccessors[ i ];
// 				var outputAccessor = outputAccessors[ i ];
// 				var sampler = samplers[ i ];
// 				var target = targets[ i ];

// 				if ( node === undefined ) continue;

// 				node.updateMatrix();
// 				node.matrixAutoUpdate = true;

// 				var 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:
// 					default:

// 						TypedKeyframeTrack = VectorKeyframeTrack;
// 						break;

// 				}

// 				var targetName = node.name ? node.name : node.uuid;

// 				var interpolation = sampler.interpolation !== undefined ? INTERPOLATION[ sampler.interpolation ] : InterpolateLinear;

// 				var targetNames = [];

// 				if ( PATH_PROPERTIES[ target.path ] === PATH_PROPERTIES.weights ) {

// 					// Node may be a Group (glTF mesh with several primitives) or a Mesh.
// 					node.traverse( function ( object ) {

// 						if ( object.isMesh === true && object.morphTargetInfluences ) {

// 							targetNames.push( object.name ? object.name : object.uuid );

// 						}

// 					} );

// 				} else {

// 					targetNames.push( targetName );

// 				}

// 				var outputArray = outputAccessor.array;

// 				if ( outputAccessor.normalized ) {

// 					var scale;

// 					if ( outputArray.constructor === Int8Array ) {

// 						scale = 1 / 127;

// 					} else if ( outputArray.constructor === Uint8Array ) {

// 						scale = 1 / 255;

// 					} else if ( outputArray.constructor == Int16Array ) {

// 						scale = 1 / 32767;

// 					} else if ( outputArray.constructor === Uint16Array ) {

// 						scale = 1 / 65535;

// 					} else {

// 						throw new Error( 'THREE.GLTFLoader: Unsupported output accessor component type.' );

// 					}

// 					var scaled = new Float32Array( outputArray.length );

// 					for ( var j = 0, jl = outputArray.length; j < jl; j ++ ) {

// 						scaled[ j ] = outputArray[ j ] * scale;

// 					}

// 					outputArray = scaled;

// 				}

// 				for ( var j = 0, jl = targetNames.length; j < jl; j ++ ) {

// 					var track = new TypedKeyframeTrack(
// 						targetNames[ j ] + '.' + PATH_PROPERTIES[ target.path ],
// 						inputAccessor.array,
// 						outputArray,
// 						interpolation
// 					);

// 					// Override interpolation with custom factory method.
// 					if ( sampler.interpolation === 'CUBICSPLINE' ) {

// 						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.

// 							return new GLTFCubicSplineInterpolant( this.times, this.values, this.getValueSize() / 3, result );

// 						};

// 						// Mark as CUBICSPLINE. `track.getInterpolation()` doesn't support custom interpolants.
// 						track.createInterpolant.isInterpolantFactoryMethodGLTFCubicSpline = true;

// 					}

// 					tracks.push( track );

// 				}

// 			}

// 			var name = animationDef.name ? animationDef.name : 'animation_' + animationIndex;

// 			return new AnimationClip( name, undefined, tracks );

// 		} );

// 	};

// 	/**
// 	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#nodes-and-hierarchy
// 	 * @param {number} nodeIndex
// 	 * @return {Promise<Object3D>}
// 	 */
// 	GLTFParser.prototype.loadNode = function ( nodeIndex ) {

// 		var json = this.json;
// 		var extensions = this.extensions;
// 		var parser = this;

// 		var nodeDef = json.nodes[ nodeIndex ];

// 		// reserve node's name before its dependencies, so the root has the intended name.
// 		var nodeName = nodeDef.name ? parser.createUniqueName( nodeDef.name ) : '';

// 		return ( function () {

// 			var pending = [];

// 			if ( nodeDef.mesh !== undefined ) {

// 				pending.push( parser.getDependency( 'mesh', nodeDef.mesh ).then( function ( mesh ) {

// 					var 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 ( var i = 0, il = nodeDef.weights.length; i < il; i ++ ) {

// 								o.morphTargetInfluences[ i ] = nodeDef.weights[ i ];

// 							}

// 						} );

// 					}

// 					return node;

// 				} ) );

// 			}

// 			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 );

// 			} );

// 			return Promise.all( pending );

// 		}() ).then( function ( objects ) {

// 			var 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 ( var 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 ) {

// 				var 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 );

// 				}

// 			}

// 			parser.associations.set( node, { type: 'nodes', index: nodeIndex } );

// 			return node;

// 		} );

// 	};

// 	/**
// 	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#scenes
// 	 * @param {number} sceneIndex
// 	 * @return {Promise<Group>}
// 	 */
// 	GLTFParser.prototype.loadScene = function () {

// 		// scene node hierachy builder

// 		function buildNodeHierachy( nodeId, parentObject, json, parser ) {

// 			var nodeDef = json.nodes[ nodeId ];

// 			return parser.getDependency( 'node', nodeId ).then( function ( node ) {

// 				if ( nodeDef.skin === undefined ) return node;

// 				// build skeleton here as well

// 				var skinEntry;

// 				return parser.getDependency( 'skin', nodeDef.skin ).then( function ( skin ) {

// 					skinEntry = skin;

// 					var pendingJoints = [];

// 					for ( var i = 0, il = skinEntry.joints.length; i < il; i ++ ) {

// 						pendingJoints.push( parser.getDependency( 'node', skinEntry.joints[ i ] ) );

// 					}

// 					return Promise.all( pendingJoints );

// 				} ).then( function ( jointNodes ) {

// 					node.traverse( function ( mesh ) {

// 						if ( ! mesh.isMesh ) return;

// 						var bones = [];
// 						var boneInverses = [];

// 						for ( var j = 0, jl = jointNodes.length; j < jl; j ++ ) {

// 							var jointNode = jointNodes[ j ];

// 							if ( jointNode ) {

// 								bones.push( jointNode );

// 								var mat = new Matrix4();

// 								if ( skinEntry.inverseBindMatrices !== undefined ) {

// 									mat.fromArray( skinEntry.inverseBindMatrices.array, j * 16 );

// 								}

// 								boneInverses.push( mat );

// 							} else {

// 								console.warn( 'THREE.GLTFLoader: Joint "%s" could not be found.', skinEntry.joints[ j ] );

// 							}

// 						}

// 						mesh.bind( new Skeleton( bones, boneInverses ), mesh.matrixWorld );

// 					} );

// 					return node;

// 				} );

// 			} ).then( function ( node ) {

// 				// build node hierachy

// 				parentObject.add( node );

// 				var pending = [];

// 				if ( nodeDef.children ) {

// 					var children = nodeDef.children;

// 					for ( var i = 0, il = children.length; i < il; i ++ ) {

// 						var child = children[ i ];
// 						pending.push( buildNodeHierachy( child, node, json, parser ) );

// 					}

// 				}

// 				return Promise.all( pending );

// 			} );

// 		}

// 		return function loadScene( sceneIndex ) {

// 			var json = this.json;
// 			var extensions = this.extensions;
// 			var sceneDef = this.json.scenes[ sceneIndex ];
// 			var parser = this;

// 			// Loader returns Group, not Scene.
// 			// See: https://github.com/mrdoob/three.js/issues/18342#issuecomment-578981172
// 			var scene = new Group();
// 			if ( sceneDef.name ) scene.name = parser.createUniqueName( sceneDef.name );

// 			assignExtrasToUserData( scene, sceneDef );

// 			if ( sceneDef.extensions ) addUnknownExtensionsToUserData( extensions, scene, sceneDef );

// 			var nodeIds = sceneDef.nodes || [];

// 			var pending = [];

// 			for ( var i = 0, il = nodeIds.length; i < il; i ++ ) {

// 				pending.push( buildNodeHierachy( nodeIds[ i ], scene, json, parser ) );

// 			}

// 			return Promise.all( pending ).then( function () {

// 				return scene;

// 			} );

// 		};

// 	}();

// 	return GLTFLoader;

// } )();

// export { GLTFLoader };
