/Demo/threejs-demo/带着canvas去流浪（14）-demo/public/GLTFLoader.js

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/**
 * @author Rich Tibbett / https://github.com/richtr
 * @author mrdoob / http://mrdoob.com/
 * @author Tony Parisi / http://www.tonyparisi.com/
 * @author Takahiro / https://github.com/takahirox
 * @author Don McCurdy / https://www.donmccurdy.com
 */

THREE.GLTFLoader = ( function () {

	function GLTFLoader( manager ) {

		this.manager = ( manager !== undefined ) ? manager : THREE.DefaultLoadingManager;
		this.dracoLoader = null;

	}

	GLTFLoader.prototype = {

		constructor: GLTFLoader,

		crossOrigin: 'anonymous',

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

			var scope = this;

			var resourcePath;

			if ( this.resourcePath !== undefined ) {

				resourcePath = this.resourcePath;

			} else if ( this.path !== undefined ) {

				resourcePath = this.path;

			} else {

				resourcePath = THREE.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.
			scope.manager.itemStart( url );

			var _onError = function ( e ) {

				if ( onError ) {

					onError( e );

				} else {

					console.error( e );

				}

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

			};

			var loader = new THREE.FileLoader( scope.manager );

			loader.setPath( this.path );
			loader.setResponseType( 'arraybuffer' );

			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 );

		},

		setCrossOrigin: function ( value ) {

			this.crossOrigin = value;
			return this;

		},

		setPath: function ( value ) {

			this.path = value;
			return this;

		},

		setResourcePath: function ( value ) {

			this.resourcePath = value;
			return this;

		},

		setDRACOLoader: function ( dracoLoader ) {

			this.dracoLoader = dracoLoader;
			return this;

		},

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

			var content;
			var extensions = {};

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

				content = data;

			} else {

				var magic = THREE.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 = THREE.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. Use LegacyGLTFLoader instead.' ) );
				return;

			}

			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_LIGHTS_PUNCTUAL:
							extensions[ extensionName ] = new GLTFLightsExtension( json );
							break;

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

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

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

						case EXTENSIONS.MSFT_TEXTURE_DDS:
							extensions[ EXTENSIONS.MSFT_TEXTURE_DDS ] = new GLTFTextureDDSExtension( json );
							break;

						case EXTENSIONS.KHR_TEXTURE_TRANSFORM:
							extensions[ EXTENSIONS.KHR_TEXTURE_TRANSFORM ] = new GLTFTextureTransformExtension( json );
							break;

						default:

							if ( extensionsRequired.indexOf( extensionName ) >= 0 ) {

								console.warn( 'THREE.GLTFLoader: Unknown extension "' + extensionName + '".' );

							}

					}

				}

			}

			var parser = new GLTFParser( json, extensions, {

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

			} );

			parser.parse( function ( scene, scenes, cameras, animations, json ) {

				var glTF = {
					scene: scene,
					scenes: scenes,
					cameras: cameras,
					animations: animations,
					asset: json.asset,
					parser: parser,
					userData: {}
				};

				addUnknownExtensionsToUserData( extensions, glTF, json );

				onLoad( glTF );

			}, 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_PBR_SPECULAR_GLOSSINESS: 'KHR_materials_pbrSpecularGlossiness',
		KHR_MATERIALS_UNLIT: 'KHR_materials_unlit',
		KHR_TEXTURE_TRANSFORM: 'KHR_texture_transform',
		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() {

		if ( ! THREE.DDSLoader ) {

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

		}

		this.name = EXTENSIONS.MSFT_TEXTURE_DDS;
		this.ddsLoader = new THREE.DDSLoader();

	}

	/**
	 * Lights Extension
	 *
	 * Specification: PENDING
	 */
	function GLTFLightsExtension( json ) {

		this.name = EXTENSIONS.KHR_LIGHTS_PUNCTUAL;

		var extension = ( json.extensions && json.extensions[ EXTENSIONS.KHR_LIGHTS_PUNCTUAL ] ) || {};
		this.lightDefs = extension.lights || [];

	}

	GLTFLightsExtension.prototype.loadLight = function ( lightIndex ) {

		var lightDef = this.lightDefs[ lightIndex ];
		var lightNode;

		var color = new THREE.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 THREE.DirectionalLight( color );
				lightNode.target.position.set( 0, 0, -1 );
				lightNode.add( lightNode.target );
				break;

			case 'point':
				lightNode = new THREE.PointLight( color );
				lightNode.distance = range;
				break;

			case 'spot':
				lightNode = new THREE.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 + '".' );

		}

		lightNode.decay = 2;

		if ( lightDef.intensity !== undefined ) lightNode.intensity = lightDef.intensity;

		lightNode.name = lightDef.name || ( 'light_' + lightIndex );

		return Promise.resolve( lightNode );

	};

	/**
	 * Unlit Materials Extension (pending)
	 *
	 * PR: https://github.com/KhronosGroup/glTF/pull/1163
	 */
	function GLTFMaterialsUnlitExtension( json ) {

		this.name = EXTENSIONS.KHR_MATERIALS_UNLIT;

	}

	GLTFMaterialsUnlitExtension.prototype.getMaterialType = function ( material ) {

		return THREE.MeshBasicMaterial;

	};

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

		var pending = [];

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

		var metallicRoughness = material.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 );

	};

	/* BINARY EXTENSION */

	var BINARY_EXTENSION_BUFFER_NAME = 'binary_glTF';
	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: THREE.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. Use LegacyGLTFLoader instead.' );

		}

		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 = THREE.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/pull/874
	 */
	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;

	}

	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 ) {

			if ( ! ( attributeName in ATTRIBUTES ) ) continue;

			threeAttributeMap[ ATTRIBUTES[ attributeName ] ] = gltfAttributeMap[ attributeName ];

		}

		for ( attributeName in primitive.attributes ) {

			if ( ATTRIBUTES[ attributeName ] !== undefined && gltfAttributeMap[ attributeName ] !== undefined ) {

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

				attributeTypeMap[ ATTRIBUTES[ attributeName ] ] = componentType;
				attributeNormalizedMap[ ATTRIBUTES[ attributeName ] ] = 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:
	 */
	function GLTFTextureTransformExtension( json ) {

		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
	 */
	function GLTFMaterialsPbrSpecularGlossinessExtension() {

		return {

			name: EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS,

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

			getMaterialType: function () {

				return THREE.ShaderMaterial;

			},

			extendParams: function ( params, material, parser ) {

				var pbrSpecularGlossiness = material.extensions[ this.name ];

				var shader = THREE.ShaderLib[ 'standard' ];

				var uniforms = THREE.UniformsUtils.clone( shader.uniforms );

				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;',
					'material.specularRoughness = clamp( 1.0 - glossinessFactor, 0.04, 1.0 );',
					'material.specularColor = specularFactor.rgb;',
				].join( '\n' );

				var 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 );

				delete uniforms.roughness;
				delete uniforms.metalness;
				delete uniforms.roughnessMap;
				delete uniforms.metalnessMap;

				uniforms.specular = { value: new THREE.Color().setHex( 0x111111 ) };
				uniforms.glossiness = { value: 0.5 };
				uniforms.specularMap = { value: null };
				uniforms.glossinessMap = { value: null };

				params.vertexShader = shader.vertexShader;
				params.fragmentShader = fragmentShader;
				params.uniforms = uniforms;
				params.defines = { 'STANDARD': '' };

				params.color = new THREE.Color( 1.0, 1.0, 1.0 );
				params.opacity = 1.0;

				var pending = [];

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

					var array = pbrSpecularGlossiness.diffuseFactor;

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

				}

				if ( pbrSpecularGlossiness.diffuseTexture !== undefined ) {

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

				}

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

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

					params.specular.fromArray( pbrSpecularGlossiness.specularFactor );

				}

				if ( pbrSpecularGlossiness.specularGlossinessTexture !== undefined ) {

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

				}

				return Promise.all( pending );

			},

			createMaterial: function ( params ) {

				// setup material properties based on MeshStandardMaterial for Specular-Glossiness

				var material = new THREE.ShaderMaterial( {
					defines: params.defines,
					vertexShader: params.vertexShader,
					fragmentShader: params.fragmentShader,
					uniforms: params.uniforms,
					fog: true,
					lights: true,
					opacity: params.opacity,
					transparent: params.transparent
				} );

				material.isGLTFSpecularGlossinessMaterial = true;

				material.color = params.color;

				material.map = params.map === undefined ? null : params.map;

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

				material.aoMap = params.aoMap === undefined ? null : params.aoMap;
				material.aoMapIntensity = 1.0;

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

				material.bumpMap = params.bumpMap === undefined ? null : params.bumpMap;
				material.bumpScale = 1;

				material.normalMap = params.normalMap === undefined ? null : params.normalMap;
				if ( params.normalScale ) material.normalScale = params.normalScale;

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

				material.specularMap = params.specularMap === undefined ? null : params.specularMap;
				material.specular = params.specular;

				material.glossinessMap = params.glossinessMap === undefined ? null : params.glossinessMap;
				material.glossiness = params.glossiness;

				material.alphaMap = null;

				material.envMap = params.envMap === undefined ? null : params.envMap;
				material.envMapIntensity = 1.0;

				material.refractionRatio = 0.98;

				material.extensions.derivatives = true;

				return material;

			},

			/**
			 * Clones a GLTFSpecularGlossinessMaterial instance. The ShaderMaterial.copy() method can
			 * copy only properties it knows about or inherits, and misses many properties that would
			 * normally be defined by MeshStandardMaterial.
			 *
			 * This method allows GLTFSpecularGlossinessMaterials to be cloned in the process of
			 * loading a glTF model, but cloning later (e.g. by the user) would require these changes
			 * AND also updating `.onBeforeRender` on the parent mesh.
			 *
			 * @param  {THREE.ShaderMaterial} source
			 * @return {THREE.ShaderMaterial}
			 */
			cloneMaterial: function ( source ) {

				var target = source.clone();

				target.isGLTFSpecularGlossinessMaterial = true;

				var params = this.specularGlossinessParams;

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

					target[ params[ i ] ] = source[ params[ i ] ];

				}

				return target;

			},

			// Here's based on refreshUniformsCommon() and refreshUniformsStandard() in WebGLRenderer.
			refreshUniforms: function ( renderer, scene, camera, geometry, material, group ) {

				if ( material.isGLTFSpecularGlossinessMaterial !== true ) {

					return;

				}

				var uniforms = material.uniforms;
				var defines = material.defines;

				uniforms.opacity.value = material.opacity;

				uniforms.diffuse.value.copy( material.color );
				uniforms.emissive.value.copy( material.emissive ).multiplyScalar( material.emissiveIntensity );

				uniforms.map.value = material.map;
				uniforms.specularMap.value = material.specularMap;
				uniforms.alphaMap.value = material.alphaMap;

				uniforms.lightMap.value = material.lightMap;
				uniforms.lightMapIntensity.value = material.lightMapIntensity;

				uniforms.aoMap.value = material.aoMap;
				uniforms.aoMapIntensity.value = material.aoMapIntensity;

				// uv repeat and offset setting priorities
				// 1. color map
				// 2. specular map
				// 3. normal map
				// 4. bump map
				// 5. alpha map
				// 6. emissive map

				var uvScaleMap;

				if ( material.map ) {

					uvScaleMap = material.map;

				} else if ( material.specularMap ) {

					uvScaleMap = material.specularMap;

				} else if ( material.displacementMap ) {

					uvScaleMap = material.displacementMap;

				} else if ( material.normalMap ) {

					uvScaleMap = material.normalMap;

				} else if ( material.bumpMap ) {

					uvScaleMap = material.bumpMap;

				} else if ( material.glossinessMap ) {

					uvScaleMap = material.glossinessMap;

				} else if ( material.alphaMap ) {

					uvScaleMap = material.alphaMap;

				} else if ( material.emissiveMap ) {

					uvScaleMap = material.emissiveMap;

				}

				if ( uvScaleMap !== undefined ) {

					// backwards compatibility
					if ( uvScaleMap.isWebGLRenderTarget ) {

						uvScaleMap = uvScaleMap.texture;

					}

					if ( uvScaleMap.matrixAutoUpdate === true ) {

						uvScaleMap.updateMatrix();

					}

					uniforms.uvTransform.value.copy( uvScaleMap.matrix );

				}

				uniforms.envMap.value = material.envMap;
				uniforms.envMapIntensity.value = material.envMapIntensity;
				uniforms.flipEnvMap.value = ( material.envMap && material.envMap.isCubeTexture ) ? - 1 : 1;

				uniforms.refractionRatio.value = material.refractionRatio;

				uniforms.specular.value.copy( material.specular );
				uniforms.glossiness.value = material.glossiness;

				uniforms.glossinessMap.value = material.glossinessMap;

				uniforms.emissiveMap.value = material.emissiveMap;
				uniforms.bumpMap.value = material.bumpMap;
				uniforms.normalMap.value = material.normalMap;

				uniforms.displacementMap.value = material.displacementMap;
				uniforms.displacementScale.value = material.displacementScale;
				uniforms.displacementBias.value = material.displacementBias;

				if ( uniforms.glossinessMap.value !== null && defines.USE_GLOSSINESSMAP === undefined ) {

					defines.USE_GLOSSINESSMAP = '';
					// set USE_ROUGHNESSMAP to enable vUv
					defines.USE_ROUGHNESSMAP = '';

				}

				if ( uniforms.glossinessMap.value === null && defines.USE_GLOSSINESSMAP !== undefined ) {

					delete defines.USE_GLOSSINESSMAP;
					delete defines.USE_ROUGHNESSMAP;

				}

			}

		};

	}

	/*********************************/
	/********** 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 ) {

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

	}

	GLTFCubicSplineInterpolant.prototype = Object.create( THREE.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 s0 = 2 * ppp - 3 * pp + 1;
		var s1 = ppp - 2 * pp + p;
		var s2 = - 2 * ppp + 3 * pp;
		var s3 = ppp - pp;

		// 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_TYPE = {
		5126: Number,
		//35674: THREE.Matrix2,
		35675: THREE.Matrix3,
		35676: THREE.Matrix4,
		35664: THREE.Vector2,
		35665: THREE.Vector3,
		35666: THREE.Vector4,
		35678: THREE.Texture
	};

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

	var WEBGL_FILTERS = {
		9728: THREE.NearestFilter,
		9729: THREE.LinearFilter,
		9984: THREE.NearestMipMapNearestFilter,
		9985: THREE.LinearMipMapNearestFilter,
		9986: THREE.NearestMipMapLinearFilter,
		9987: THREE.LinearMipMapLinearFilter
	};

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

	var WEBGL_SIDES = {
		1028: THREE.BackSide, // Culling front
		1029: THREE.FrontSide // Culling back
		//1032: THREE.NoSide   // Culling front and back, what to do?
	};

	var WEBGL_DEPTH_FUNCS = {
		512: THREE.NeverDepth,
		513: THREE.LessDepth,
		514: THREE.EqualDepth,
		515: THREE.LessEqualDepth,
		516: THREE.GreaterEqualDepth,
		517: THREE.NotEqualDepth,
		518: THREE.GreaterEqualDepth,
		519: THREE.AlwaysDepth
	};

	var WEBGL_BLEND_EQUATIONS = {
		32774: THREE.AddEquation,
		32778: THREE.SubtractEquation,
		32779: THREE.ReverseSubtractEquation
	};

	var WEBGL_BLEND_FUNCS = {
		0: THREE.ZeroFactor,
		1: THREE.OneFactor,
		768: THREE.SrcColorFactor,
		769: THREE.OneMinusSrcColorFactor,
		770: THREE.SrcAlphaFactor,
		771: THREE.OneMinusSrcAlphaFactor,
		772: THREE.DstAlphaFactor,
		773: THREE.OneMinusDstAlphaFactor,
		774: THREE.DstColorFactor,
		775: THREE.OneMinusDstColorFactor,
		776: THREE.SrcAlphaSaturateFactor
		// The followings are not supported by Three.js yet
		//32769: CONSTANT_COLOR,
		//32770: ONE_MINUS_CONSTANT_COLOR,
		//32771: CONSTANT_ALPHA,
		//32772: ONE_MINUS_CONSTANT_COLOR
	};

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

	var ATTRIBUTES = {
		POSITION: 'position',
		NORMAL: 'normal',
		TEXCOORD_0: 'uv',
		TEXCOORD0: 'uv', // deprecated
		TEXCOORD: 'uv', // deprecated
		TEXCOORD_1: 'uv2',
		COLOR_0: 'color',
		COLOR0: 'color', // deprecated
		COLOR: 'color', // deprecated
		WEIGHTS_0: 'skinWeight',
		WEIGHT: 'skinWeight', // deprecated
		JOINTS_0: 'skinIndex',
		JOINT: 'skinIndex' // deprecated
	};

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

	var INTERPOLATION = {
		CUBICSPLINE: THREE.InterpolateSmooth, // We use custom interpolation GLTFCubicSplineInterpolation for CUBICSPLINE.
		                                      // KeyframeTrack.optimize() can't handle glTF Cubic Spline output values layout,
		                                      // using THREE.InterpolateSmooth for KeyframeTrack instantiation to prevent optimization.
		                                      // See KeyframeTrack.optimize() for the detail.
		LINEAR: THREE.InterpolateLinear,
		STEP: THREE.InterpolateDiscrete
	};

	var STATES_ENABLES = {
		2884: 'CULL_FACE',
		2929: 'DEPTH_TEST',
		3042: 'BLEND',
		3089: 'SCISSOR_TEST',
		32823: 'POLYGON_OFFSET_FILL',
		32926: 'SAMPLE_ALPHA_TO_COVERAGE'
	};

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

	var MIME_TYPE_FORMATS = {
		'image/png': THREE.RGBAFormat,
		'image/jpeg': THREE.RGBFormat
	};

	/* UTILITY FUNCTIONS */

	function resolveURL( url, path ) {

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

		// 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() {

		return new THREE.MeshStandardMaterial( {
			color: 0xFFFFFF,
			emissive: 0x000000,
			metalness: 1,
			roughness: 1,
			transparent: false,
			depthTest: true,
			side: THREE.FrontSide
		} );

	}

	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 {THREE.Object3D|THREE.Material|THREE.BufferGeometry} object
	 * @param {GLTF.definition} gltfDef
	 */
	function assignExtrasToUserData( object, gltfDef ) {

		if ( gltfDef.extras !== undefined ) {

			if ( typeof gltfDef.extras === 'object' ) {

				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 {THREE.BufferGeometry} geometry
	 * @param {Array<GLTF.Target>} targets
	 * @param {GLTFParser} parser
	 * @return {Promise<THREE.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 accessor = target.POSITION !== undefined
					? parser.getDependency( 'accessor', target.POSITION )
						.then( function ( accessor ) {
							// Cloning not to pollute original accessor below
							return cloneBufferAttribute( accessor );
						} )
					: geometry.attributes.position;

				pendingPositionAccessors.push( accessor );

			}

			if ( hasMorphNormal ) {

				var accessor = target.NORMAL !== undefined
					? parser.getDependency( 'accessor', target.NORMAL )
						.then( function ( accessor ) {
							return cloneBufferAttribute( accessor );
						} )
					: geometry.attributes.normal;

				pendingNormalAccessors.push( accessor );

			}

		}

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

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

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

				var target = targets[ i ];
				var attributeName = 'morphTarget' + i;

				if ( hasMorphPosition ) {

					// Three.js morph position is absolute value. The formula is
					//   basePosition
					//     + weight0 * ( morphPosition0 - basePosition )
					//     + weight1 * ( morphPosition1 - basePosition )
					//     ...
					// while the glTF one is relative
					//   basePosition
					//     + weight0 * glTFmorphPosition0
					//     + weight1 * glTFmorphPosition1
					//     ...
					// then we need to convert from relative to absolute here.

					if ( target.POSITION !== undefined ) {

						var positionAttribute = morphPositions[ i ];
						positionAttribute.name = attributeName;

						var position = geometry.attributes.position;

						for ( var j = 0, jl = positionAttribute.count; j < jl; j ++ ) {

							positionAttribute.setXYZ(
								j,
								positionAttribute.getX( j ) + position.getX( j ),
								positionAttribute.getY( j ) + position.getY( j ),
								positionAttribute.getZ( j ) + position.getZ( j )
							);

						}

					}

				}

				if ( hasMorphNormal ) {

					// see target.POSITION's comment

					if ( target.NORMAL !== undefined ) {

						var normalAttribute = morphNormals[ i ];
						normalAttribute.name = attributeName;

						var normal = geometry.attributes.normal;

						for ( var j = 0, jl = normalAttribute.count; j < jl; j ++ ) {

							normalAttribute.setXYZ(
								j,
								normalAttribute.getX( j ) + normal.getX( j ),
								normalAttribute.getY( j ) + normal.getY( j ),
								normalAttribute.getZ( j ) + normal.getZ( j )
							);

						}

					}

				}

			}

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

			return geometry;

		} );

	}

	/**
	 * @param {THREE.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 isPrimitiveEqual( a, b ) {

		if ( a.indices !== b.indices ) {

			return false;

		}

		return isObjectEqual( a.attributes, b.attributes );

	}

	function isObjectEqual( a, b ) {

		if ( Object.keys( a ).length !== Object.keys( b ).length ) return false;

		for ( var key in a ) {

			if ( a[ key ] !== b[ key ] ) return false;

		}

		return true;

	}

	function isArrayEqual( a, b ) {

		if ( a.length !== b.length ) return false;

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

			if ( a[ i ] !== b[ i ] ) return false;

		}

		return true;

	}

	function getCachedGeometry( cache, newPrimitive ) {

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

			var cached = cache[ i ];

			if ( isPrimitiveEqual( cached.primitive, newPrimitive ) ) return cached.promise;

		}

		return null;

	}

	function getCachedCombinedGeometry( cache, geometries ) {

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

			var cached = cache[ i ];

			if ( isArrayEqual( geometries, cached.baseGeometries ) ) return cached.geometry;

		}

		return null;

	}

	function getCachedMultiPassGeometry( cache, geometry, primitives ) {

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

			var cached = cache[ i ];

			if ( geometry === cached.baseGeometry && isArrayEqual( primitives, cached.primitives ) ) return cached.geometry;

		}

		return null;

	}

	function cloneBufferAttribute( attribute ) {

		if ( attribute.isInterleavedBufferAttribute ) {

			var count = attribute.count;
			var itemSize = attribute.itemSize;
			var array = attribute.array.slice( 0, count * itemSize );

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

				array[ i ] = attribute.getX( i );
				if ( itemSize >= 2 ) array[ i + 1 ] = attribute.getY( i );
				if ( itemSize >= 3 ) array[ i + 2 ] = attribute.getZ( i );
				if ( itemSize >= 4 ) array[ i + 3 ] = attribute.getW( i );

			}

			return new THREE.BufferAttribute( array, itemSize, attribute.normalized );

		}

		return attribute.clone();

	}

	/**
	 * Checks if we can build a single Mesh with MultiMaterial from multiple primitives.
	 * Returns true if all primitives use the same attributes/morphAttributes/mode
	 * and also have index. Otherwise returns false.
	 *
	 * @param {Array<GLTF.Primitive>} primitives
	 * @return {Boolean}
	 */
	function isMultiPassGeometry( primitives ) {

		if ( primitives.length < 2 ) return false;

		var primitive0 = primitives[ 0 ];
		var targets0 = primitive0.targets || [];

		if ( primitive0.indices === undefined ) return false;

		for ( var i = 1, il = primitives.length; i < il; i ++ ) {

			var primitive = primitives[ i ];

			if ( primitive0.mode !== primitive.mode ) return false;
			if ( primitive.indices === undefined ) return false;
			if ( ! isObjectEqual( primitive0.attributes, primitive.attributes ) ) return false;

			var targets = primitive.targets || [];

			if ( targets0.length !== targets.length ) return false;

			for ( var j = 0, jl = targets0.length; j < jl; j ++ ) {

				if ( ! isObjectEqual( targets0[ j ], targets[ j ] ) ) return false;

			}

		}

		return true;

	}

	/* GLTF PARSER */

	function GLTFParser( json, extensions, options ) {

		this.json = json || {};
		this.extensions = extensions || {};
		this.options = options || {};

		// loader object cache
		this.cache = new GLTFRegistry();

		// BufferGeometry caching
		this.primitiveCache = [];
		this.multiplePrimitivesCache = [];
		this.multiPassGeometryCache = [];

		this.textureLoader = new THREE.TextureLoader( this.options.manager );
		this.textureLoader.setCrossOrigin( this.options.crossOrigin );

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

	}

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

		var json = this.json;

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

		// Mark the special nodes/meshes in json for efficient parse
		this.markDefs();

		// Fire the callback on complete
		this.getMultiDependencies( [

			'scene',
			'animation',
			'camera'

		] ).then( function ( dependencies ) {

			var scenes = dependencies.scenes || [];
			var scene = scenes[ json.scene || 0 ];
			var animations = dependencies.animations || [];
			var cameras = dependencies.cameras || [];

			onLoad( scene, scenes, cameras, animations, json );

		} ).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 || [];

		var meshReferences = {};
		var meshUses = {};

		// 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;

			}

		}

		// Meshes can (and should) be reused by multiple nodes in a glTF asset. To
		// avoid having more than one THREE.Mesh with the same name, count
		// references and rename instances below.
		//
		// Example: CesiumMilkTruck sample model reuses "Wheel" meshes.
		for ( var nodeIndex = 0, nodeLength = nodeDefs.length; nodeIndex < nodeLength; nodeIndex ++ ) {

			var nodeDef = nodeDefs[ nodeIndex ];

			if ( nodeDef.mesh !== undefined ) {

				if ( meshReferences[ nodeDef.mesh ] === undefined ) {

					meshReferences[ nodeDef.mesh ] = meshUses[ nodeDef.mesh ] = 0;

				}

				meshReferences[ 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;

				}

			}

		}

		this.json.meshReferences = meshReferences;
		this.json.meshUses = meshUses;

	};

	/**
	 * Requests the specified dependency asynchronously, with caching.
	 * @param {string} type
	 * @param {number} index
	 * @return {Promise<THREE.Object3D|THREE.Material|THREE.Texture|THREE.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.loadMesh( index );
					break;

				case 'accessor':
					dependency = this.loadAccessor( index );
					break;

				case 'bufferView':
					dependency = this.loadBufferView( index );
					break;

				case 'buffer':
					dependency = this.loadBuffer( index );
					break;

				case 'material':
					dependency = this.loadMaterial( index );
					break;

				case 'texture':
					dependency = this.loadTexture( index );
					break;

				case 'skin':
					dependency = this.loadSkin( index );
					break;

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

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

				case 'light':
					dependency = this.extensions[ EXTENSIONS.KHR_LIGHTS_PUNCTUAL ].loadLight( 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;

	};

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

		var results = {};
		var pending = [];

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

			var type = types[ i ];
			var value = this.getDependencies( type );

			value = value.then( function ( key, value ) {

				results[ key ] = value;

			}.bind( this, type + ( type === 'mesh' ? 'es' : 's' ) ) );

			pending.push( value );

		}

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

			return results;

		} );

	};

	/**
	 * 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<THREE.BufferAttribute|THREE.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 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 ) {

				var ibCacheKey = 'InterleavedBuffer:' + accessorDef.bufferView + ':' + accessorDef.componentType;
				var ib = parser.cache.get( ibCacheKey );

				if ( ! ib ) {

					// Use the full buffer if it's interleaved.
					array = new TypedArray( bufferView );

					// Integer parameters to IB/IBA are in array elements, not bytes.
					ib = new THREE.InterleavedBuffer( array,…