text: /**
   * @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;
  
  	}
  
  	GLTFLoader.prototype = {
  
  		constructor: GLTFLoader,
  
  		crossOrigin: 'Anonymous',
  
  		load: function ( url, onLoad, onProgress, onError ) {
  
  			var scope = this;
  
  			var path = this.path !== undefined ? this.path : THREE.LoaderUtils.extractUrlBase( url );
  
  			var loader = new THREE.FileLoader( scope.manager );
  
  			loader.setResponseType( 'arraybuffer' );
  
  			loader.load( url, function ( data ) {
  
  				try {
  
  					scope.parse( data, path, onLoad, onError );
  
  				} catch ( e ) {
  
  					if ( onError !== undefined ) {
  
  						onError( e );
  
  					} else {
  
  						throw e;
  
  					}
  
  				}
  
  			}, onProgress, onError );
  
  		},
  
  		setCrossOrigin: function ( value ) {
  
  			this.crossOrigin = value;
  			return this;
  
  		},
  
  		setPath: function ( value ) {
  
  			this.path = value;
  			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 ) {
  
  				if ( json.extensionsUsed.indexOf( EXTENSIONS.KHR_LIGHTS ) >= 0 ) {
  
  					extensions[ EXTENSIONS.KHR_LIGHTS ] = new GLTFLightsExtension( json );
  
  				}
  
  				if ( json.extensionsUsed.indexOf( EXTENSIONS.KHR_MATERIALS_COMMON ) >= 0 ) {
  
  					extensions[ EXTENSIONS.KHR_MATERIALS_COMMON ] = new GLTFMaterialsCommonExtension( json );
  
  				}
  
  				if ( json.extensionsUsed.indexOf( EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS ) >= 0 ) {
  
  					extensions[ EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS ] = new GLTFMaterialsPbrSpecularGlossinessExtension();
  
  				}
  
  			}
  
  			console.time( 'GLTFLoader' );
  
  			var parser = new GLTFParser( json, extensions, {
  
  				path: path || this.path || '',
  				crossOrigin: this.crossOrigin,
  				manager: this.manager
  
  			} );
  
  			parser.parse( function ( scene, scenes, cameras, animations, asset ) {
  
  				console.timeEnd( 'GLTFLoader' );
  
  				var glTF = {
  					scene: scene,
  					scenes: scenes,
  					cameras: cameras,
  					animations: animations,
  					asset: asset
  				};
  
  				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_LIGHTS: 'KHR_lights',
  		KHR_MATERIALS_COMMON: 'KHR_materials_common',
  		KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS: 'KHR_materials_pbrSpecularGlossiness'
  	};
  
  	/**
  	 * Lights Extension
  	 *
  	 * Specification: PENDING
  	 */
  	function GLTFLightsExtension( json ) {
  
  		this.name = EXTENSIONS.KHR_LIGHTS;
  
  		this.lights = {};
  
  		var extension = ( json.extensions && json.extensions[ EXTENSIONS.KHR_LIGHTS ] ) || {};
  		var lights = extension.lights || {};
  
  		for ( var lightId in lights ) {
  
  			var light = lights[ lightId ];
  			var lightNode;
  
  			var color = new THREE.Color().fromArray( light.color );
  
  			switch ( light.type ) {
  
  				case 'directional':
  					lightNode = new THREE.DirectionalLight( color );
  					lightNode.position.set( 0, 0, 1 );
  					break;
  
  				case 'point':
  					lightNode = new THREE.PointLight( color );
  					break;
  
  				case 'spot':
  					lightNode = new THREE.SpotLight( color );
  					lightNode.position.set( 0, 0, 1 );
  					break;
  
  				case 'ambient':
  					lightNode = new THREE.AmbientLight( color );
  					break;
  
  			}
  
  			if ( lightNode ) {
  
  				if ( light.constantAttenuation !== undefined ) {
  
  					lightNode.intensity = light.constantAttenuation;
  
  				}
  
  				if ( light.linearAttenuation !== undefined ) {
  
  					lightNode.distance = 1 / light.linearAttenuation;
  
  				}
  
  				if ( light.quadraticAttenuation !== undefined ) {
  
  					lightNode.decay = light.quadraticAttenuation;
  
  				}
  
  				if ( light.fallOffAngle !== undefined ) {
  
  					lightNode.angle = light.fallOffAngle;
  
  				}
  
  				if ( light.fallOffExponent !== undefined ) {
  
  					console.warn( 'THREE.GLTFLoader:: light.fallOffExponent not currently supported.' );
  
  				}
  
  				lightNode.name = light.name || ( 'light_' + lightId );
  				this.lights[ lightId ] = lightNode;
  
  			}
  
  		}
  
  	}
  
  	/**
  	 * Common Materials Extension
  	 *
  	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/Khronos/KHR_materials_common
  	 */
  	function GLTFMaterialsCommonExtension( json ) {
  
  		this.name = EXTENSIONS.KHR_MATERIALS_COMMON;
  
  	}
  
  	GLTFMaterialsCommonExtension.prototype.getMaterialType = function ( material ) {
  
  		var khrMaterial = material.extensions[ this.name ];
  
  		switch ( khrMaterial.type ) {
  
  			case 'commonBlinn' :
  			case 'commonPhong' :
  				return THREE.MeshPhongMaterial;
  
  			case 'commonLambert' :
  				return THREE.MeshLambertMaterial;
  
  			case 'commonConstant' :
  			default :
  				return THREE.MeshBasicMaterial;
  
  		}
  
  	};
  
  	GLTFMaterialsCommonExtension.prototype.extendParams = function ( materialParams, material, parser ) {
  
  		var khrMaterial = material.extensions[ this.name ];
  
  		var pending = [];
  
  		var keys = [];
  
  		// TODO: Currently ignored: 'ambientFactor', 'ambientTexture'
  		switch ( khrMaterial.type ) {
  
  			case 'commonBlinn' :
  			case 'commonPhong' :
  				keys.push( 'diffuseFactor', 'diffuseTexture', 'specularFactor', 'specularTexture', 'shininessFactor' );
  				break;
  
  			case 'commonLambert' :
  				keys.push( 'diffuseFactor', 'diffuseTexture' );
  				break;
  
  			case 'commonConstant' :
  			default :
  				break;
  
  		}
  
  		var materialValues = {};
  
  		keys.forEach( function ( v ) {
  
  			if ( khrMaterial[ v ] !== undefined ) materialValues[ v ] = khrMaterial[ v ];
  
  		} );
  
  		if ( materialValues.diffuseFactor !== undefined ) {
  
  			materialParams.color = new THREE.Color().fromArray( materialValues.diffuseFactor );
  			materialParams.opacity = materialValues.diffuseFactor[ 3 ];
  
  		}
  
  		if ( materialValues.diffuseTexture !== undefined ) {
  
  			pending.push( parser.assignTexture( materialParams, 'map', materialValues.diffuseTexture.index ) );
  
  		}
  
  		if ( materialValues.specularFactor !== undefined ) {
  
  			materialParams.specular = new THREE.Color().fromArray( materialValues.specularFactor );
  
  		}
  
  		if ( materialValues.specularTexture !== undefined ) {
  
  			pending.push( parser.assignTexture( materialParams, 'specularMap', materialValues.specularTexture.index ) );
  
  		}
  
  		if ( materialValues.shininessFactor !== undefined ) {
  
  			materialParams.shininess = materialValues.shininessFactor;
  
  		}
  
  		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.' );
  
  		}
  
  	}
  
  	/**
  	 * Specular-Glossiness Extension
  	 *
  	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/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( '#include <specularmap_fragment>', '' )
  					.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.index ) );
  
  				}
  
  				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 specGlossIndex = pbrSpecularGlossiness.specularGlossinessTexture.index;
  					pending.push( parser.assignTexture( params, 'glossinessMap', specGlossIndex ) );
  					pending.push( parser.assignTexture( params, 'specularMap', specGlossIndex ) );
  
  				}
  
  				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 ) {
  
  				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;
  
  					}
  
  					var offset;
  					var repeat;
  
  					if ( uvScaleMap.matrix !== undefined ) {
  
  						// > r88.
  
  						if ( uvScaleMap.matrixAutoUpdate === true ) {
  
  							offset = uvScaleMap.offset;
  							repeat = uvScaleMap.repeat;
  							var rotation = uvScaleMap.rotation;
  							var center = uvScaleMap.center;
  
  							uvScaleMap.matrix.setUvTransform( offset.x, offset.y, repeat.x, repeat.y, rotation, center.x, center.y );
  
  						}
  
  						uniforms.uvTransform.value.copy( uvScaleMap.matrix );
  
  					} else {
  
  						// <= r87. Remove when reasonable.
  
  						offset = uvScaleMap.offset;
  						repeat = uvScaleMap.repeat;
  
  						uniforms.offsetRepeat.value.set( offset.x, offset.y, repeat.x, repeat.y );
  
  					}
  
  				}
  
  				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;
  
  				}
  
  			}
  
  		};
  
  	}
  
  	/*********************************/
  	/********** 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_TEXTURE_FORMATS = {
  		6406: THREE.AlphaFormat,
  		6407: THREE.RGBFormat,
  		6408: THREE.RGBAFormat,
  		6409: THREE.LuminanceFormat,
  		6410: THREE.LuminanceAlphaFormat
  	};
  
  	var WEBGL_TEXTURE_DATATYPES = {
  		5121: THREE.UnsignedByteType,
  		32819: THREE.UnsignedShort4444Type,
  		32820: THREE.UnsignedShort5551Type,
  		33635: THREE.UnsignedShort565Type
  	};
  
  	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 PATH_PROPERTIES = {
  		scale: 'scale',
  		translation: 'position',
  		rotation: 'quaternion',
  		weights: 'morphTargetInfluences'
  	};
  
  	var INTERPOLATION = {
  		CUBICSPLINE: THREE.InterpolateSmooth,
  		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'
  	};
  
  	/* 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
  		} );
  
  	}
  
  	/**
  	 * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#morph-targets
  	 *
  	 * TODO: Implement support for morph targets on TANGENT attribute.
  	 *
  	 * @param {THREE.Mesh} mesh
  	 * @param {GLTF.Mesh} meshDef
  	 * @param {GLTF.Primitive} primitiveDef
  	 * @param {Array<THREE.BufferAttribute>} accessors
  	 */
  	function addMorphTargets( mesh, meshDef, primitiveDef, accessors ) {
  
  		var geometry = mesh.geometry;
  		var material = mesh.material;
  
  		var targets = primitiveDef.targets;
  		var morphAttributes = geometry.morphAttributes;
  
  		morphAttributes.position = [];
  		morphAttributes.normal = [];
  
  		material.morphTargets = true;
  
  		for ( var i = 0, il = targets.length; i < il; i ++ ) {
  
  			var target = targets[ i ];
  			var attributeName = 'morphTarget' + i;
  
  			var positionAttribute, normalAttribute;
  
  			if ( target.POSITION !== undefined ) {
  
  				// Three.js morph formula is
  				//   position
  				//     + weight0 * ( morphTarget0 - position )
  				//     + weight1 * ( morphTarget1 - position )
  				//     ...
  				// while the glTF one is
  				//   position
  				//     + weight0 * morphTarget0
  				//     + weight1 * morphTarget1
  				//     ...
  				// then adding position to morphTarget.
  				// So morphTarget value will depend on mesh's position, then cloning attribute
  				// for the case if attribute is shared among two or more meshes.
  
  				positionAttribute = accessors[ target.POSITION ].clone();
  				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 )
  					);
  
  				}
  
  			} else if ( geometry.attributes.position ) {
  
  				// Copying the original position not to affect the final position.
  				// See the formula above.
  				positionAttribute = geometry.attributes.position.clone();
  
  			}
  
  			if ( positionAttribute !== undefined ) {
  
  				positionAttribute.name = attributeName;
  				morphAttributes.position.push( positionAttribute );
  
  			}
  
  			if ( target.NORMAL !== undefined ) {
  
  				material.morphNormals = true;
  
  				// see target.POSITION's comment
  
  				normalAttribute = accessors[ target.NORMAL ].clone();
  				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 )
  					);
  
  				}
  
  			} else if ( geometry.attributes.normal !== undefined ) {
  
  				normalAttribute = geometry.attributes.normal.clone();
  
  			}
  
  			if ( normalAttribute !== undefined ) {
  
  				normalAttribute.name = attributeName;
  				morphAttributes.normal.push( normalAttribute );
  
  			}
  
  		}
  
  		mesh.updateMorphTargets();
  
  		if ( meshDef.weights !== undefined ) {
  
  			for ( var i = 0, il = meshDef.weights.length; i < il; i ++ ) {
  
  				mesh.morphTargetInfluences[ i ] = meshDef.weights[ i ];
  
  			}
  
  		}
  
  	}
  
  	function isPrimitiveEqual( a, b ) {
  
  		if ( a.indices !== b.indices ) {
  
  			return false;
  
  		}
  
  		var attribA = a.attributes || {};
  		var attribB = b.attributes || {};
  		var keysA = Object.keys( attribA );
  		var keysB = Object.keys( attribB );
  
  		if ( keysA.length !== keysB.length ) {
  
  			return false;
  
  		}
  
  		for ( var i = 0, il = keysA.length; i < il; i ++ ) {
  
  			var key = keysA[ i ];
  
  			if ( attribA[ key ] !== attribB[ key ] ) {
  
  				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.geometry;
  
  			}
  
  		}
  
  		return null;
  
  	}
  
  	/* 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.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;
  		var parser = this;
  
  		// 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 asset = json.asset;
  			var cameras = dependencies.cameras || [];
  
  			onLoad( scene, scenes, cameras, animations, asset );
  
  		} ).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<Object>}
  	 */
  	GLTFParser.prototype.getDependency = function ( type, index ) {
  
  		var cacheKey = type + ':' + index;
  		var dependency = this.cache.get( cacheKey );
  
  		if ( ! dependency ) {
  
  			var fnName = 'load' + type.charAt( 0 ).toUpperCase() + type.slice( 1 );
  			dependency = this[ fnName ]( index );
  			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 pendings = [];
  
  		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' ) ) );
  
  			pendings.push( value );
  
  		}
  
  		return Promise.all( pendings ).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 json = this.json;
  
  		var accessorDef = this.json.accessors[ accessorIndex ];
  
  		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 = json.bufferViews[ accessorDef.bufferView ].byteStride;
  			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 ) {
  
  				// Use the full buffer if it's interleaved.
  				array = new TypedArray( bufferView );
  
  				// Integer parameters to IB/IBA are in array elements, not bytes.
  				var ib = new THREE.InterleavedBuffer( array, byteStride / elementBytes );
  
  				bufferAttribute = new THREE.InterleavedBufferAttribute( ib, itemSize, byteOffset / elementBytes, normalized );
  
  			} else {
  
  				if ( bufferView === null ) {
  
  					array = new TypedArray( accessorDef.count * itemSize );
  
  				} else {
  
  					array = new TypedArray( bufferView, byteOffset, accessorDef.count * itemSize );
  
  				}
  
  				bufferAttribute = new THREE.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.setArray( bufferAttribute.array.slice() );
  
  				}
  
  				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 textureLoader = this.textureLoader;
  
  		var URL = window.URL || window.webkitURL;
  
  		var textureDef = json.textures[ textureIndex ];
  		var source = json.images[ textureDef.source ];
  		var sourceURI = source.uri;
  		var isObjectURL = false;
  
  		if ( source.bufferView !== undefined ) {
  
  			// Load binary image data from bufferView, if provided.
  
  			sourceURI = parser.getDependency( 'bufferView', source.bufferView ).then( function ( bufferView ) {
  
  				isObjectURL = true;
  				var blob = new Blob( [ bufferView ], { type: source.mimeType } );
  				sourceURI = URL.createObjectURL( blob );
  				return sourceURI;
  
  			} );
  
  		}
  
  		return Promise.resolve( sourceURI ).then( function ( sourceURI ) {
  
  			// Load Texture resource.
  
  			var loader = THREE.Loader.Handlers.get( sourceURI ) || textureLoader;
  
  			return new Promise( function ( resolve, reject ) {
  
  				loader.load( resolveURL( sourceURI, options.path ), resolve, undefined, reject );
  
  			} );
  
  		} ).then( function ( texture ) {
  
  			// Clean up resources and configure Texture.
  
  			if ( isObjectURL === true ) {
  
  				URL.revokeObjectURL( sourceURI );
  
  			}
  
  			texture.flipY = false;
  
  			if ( textureDef.name !== undefined ) texture.name = textureDef.name;
  
  			texture.format = textureDef.format !== undefined ? WEBGL_TEXTURE_FORMATS[ textureDef.format ] : THREE.RGBAFormat;
  
  			if ( textureDef.internalFormat !== undefined && texture.format !== WEBGL_TEXTURE_FORMATS[ textureDef.internalFormat ] ) {
  
  				console.warn( 'THREE.GLTFLoader: Three.js does not support texture internalFormat which is different from texture format. ' +
  											'internalFormat will be forced to be the same value as format.' );
  
  			}
  
  			texture.type = textureDef.type !== undefined ? WEBGL_TEXTURE_DATATYPES[ textureDef.type ] : THREE.UnsignedByteType;
  
  			var samplers = json.samplers || {};
  			var sampler = samplers[ textureDef.sampler ] || {};
  
  			texture.magFilter = WEBGL_FILTERS[ sampler.magFilter ] || THREE.LinearFilter;
  			texture.minFilter = WEBGL_FILTERS[ sampler.minFilter ] || THREE.LinearMipMapLinearFilter;
  			texture.wrapS = WEBGL_WRAPPINGS[ sampler.wrapS ] || THREE.RepeatWrapping;
  			texture.wrapT = WEBGL_WRAPPINGS[ sampler.wrapT ] || THREE.RepeatWrapping;
  
  			return texture;
  
  		} );
  
  	};
  
  	/**
  	 * Asynchronously assigns a texture to the given material parameters.
  	 * @param {Object} materialParams
  	 * @param {string} textureName
  	 * @param {number} textureIndex
  	 * @return {Promise}
  	 */
  	GLTFParser.prototype.assignTexture = function ( materialParams, textureName, textureIndex ) {
  
  		return this.getDependency( 'texture', textureIndex ).then( function ( texture ) {
  
  			materialParams[ textureName ] = texture;
  
  		} );
  
  	};
  
  	/**
  	 * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#materials
  	 * @param {number} materialIndex
  	 * @return {Promise<THREE.Material>}
  	 */
  	GLTFParser.prototype.loadMaterial = function ( materialIndex ) {
  
  		var parser = this;
  		var json = this.json;
  		var extensions = this.extensions;
  		var materialDef = this.json.materials[ materialIndex ];
  
  		var materialType;
  		var materialParams = {};
  		var materialExtensions = materialDef.extensions || {};
  
  		var pending = [];
  
  		if ( materialExtensions[ EXTENSIONS.KHR_MATERIALS_COMMON ] ) {
  
  			var khcExtension = extensions[ EXTENSIONS.KHR_MATERIALS_COMMON ];
  			materialType = khcExtension.getMaterialType( materialDef );
  			pending.push( khcExtension.extendParams( materialParams, materialDef, parser ) );
  
  		} else if ( materialExtensions[ EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS ] ) {
  
  			var sgExtension = extensions[ EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS ];
  			materialType = sgExtension.getMaterialType( materialDef );
  			pending.push( sgExtension.extendParams( materialParams, materialDef, parser ) );
  
  		} else if ( materialDef.pbrMetallicRoughness !== undefined ) {
  
  			// Specification:
  			// https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#metallic-roughness-material
  
  			materialType = THREE.MeshStandardMaterial;
  
  			var metallicRoughness = materialDef.pbrMetallicRoughness;
  
  			materialParams.color = new THREE.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.index ) );
  
  			}
  
  			materialParams.metalness = metallicRoughness.metallicFactor !== undefined ? metallicRoughness.metallicFactor : 1.0;
  			materialParams.roughness = metallicRoughness.roughnessFactor !== undefined ? metallicRoughness.roughnessFactor : 1.0;
  
  			if ( metallicRoughness.metallicRoughnessTexture !== undefined ) {
  
  				var textureIndex = metallicRoughness.metallicRoughnessTexture.index;
  				pending.push( parser.assignTexture( materialParams, 'metalnessMap', textureIndex ) );
  				pending.push( parser.assignTexture( materialParams, 'roughnessMap', textureIndex ) );
  
  			}
  
  		} else {
  
  			materialType = THREE.MeshPhongMaterial;
  
  		}
  
  		if ( materialDef.doubleSided === true ) {
  
  			materialParams.side = THREE.DoubleSide;
  
  		}
  
  		var alphaMode = materialDef.alphaMode || ALPHA_MODES.OPAQUE;
  
  		if ( alphaMode === ALPHA_MODES.BLEND ) {
  
  			materialParams.transparent = true;
  
  		} else {
  
  			materialParams.transparent = false;
  
  			if ( alphaMode === ALPHA_MODES.MASK ) {
  
  				materialParams.alphaTest = materialDef.alphaCutoff !== undefined ? materialDef.alphaCutoff : 0.5;
  
  			}
  
  		}
  
  		if ( materialDef.normalTexture !== undefined ) {
  
  			pending.push( parser.assignTexture( materialParams, 'normalMap', materialDef.normalTexture.index ) );
  
  			materialParams.normalScale = new THREE.Vector2( 1, 1 );
  
  			if ( materialDef.normalTexture.scale !== undefined ) {
  
  				materialParams.normalScale.set( materialDef.normalTexture.scale, materialDef.normalTexture.scale );
  
  			}
  
  		}
  
  		if ( materialDef.occlusionTexture !== undefined ) {
  
  			pending.push( parser.assignTexture( materialParams, 'aoMap', materialDef.occlusionTexture.index ) );
  
  			if ( materialDef.occlusionTexture.strength !== undefined ) {
  
  				materialParams.aoMapIntensity = materialDef.occlusionTexture.strength;
  
  			}
  
  		}
  
  		if ( materialDef.emissiveFactor !== undefined ) {
  
  			if ( materialType === THREE.MeshBasicMaterial ) {
  
  				materialParams.color = new THREE.Color().fromArray( materialDef.emissiveFactor );
  
  			} else {
  
  				materialParams.emissive = new THREE.Color().fromArray( materialDef.emissiveFactor );
  
  			}
  
  		}
  
  		if ( materialDef.emissiveTexture !== undefined ) {
  
  			if ( materialType === THREE.MeshBasicMaterial ) {
  
  				pending.push( parser.assignTexture( materialParams, 'map', materialDef.emissiveTexture.index ) );
  
  			} else {
  
  				pending.push( parser.assignTexture( materialParams, 'emissiveMap', materialDef.emissiveTexture.index ) );
  
  			}
  
  		}
  
  		return Promise.all( pending ).then( function () {
  
  			var material;
  
  			if ( materialType === THREE.ShaderMaterial ) {
  
  				material = extensions[ EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS ].createMaterial( materialParams );
  
  			} else {
  
  				material = new materialType( materialParams );
  
  			}
  
  			if ( materialDef.name !== undefined ) material.name = materialDef.name;
  
  			// Normal map textures use OpenGL conventions:
  			// https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#materialnormaltexture
  			if ( material.normalScale ) {
  
  				material.normalScale.x = - material.normalScale.x;
  
  			}
  
  			// emissiveTexture and baseColorTexture use sRGB encoding.
  			if ( material.map ) material.map.encoding = THREE.sRGBEncoding;
  			if ( material.emissiveMap ) material.emissiveMap.encoding = THREE.sRGBEncoding;
  
  			if ( materialDef.extras ) material.userData = materialDef.extras;
  
  			return material;
  
  		} );
  
  	};
  
  	/**
  	 * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#geometry
  	 * @param {Array<Object>} primitives
  	 * @return {Promise<Array<THREE.BufferGeometry>>}
  	 */
  	GLTFParser.prototype.loadGeometries = function ( primitives ) {
  
  		var cache = this.primitiveCache;
  
  		return this.getDependencies( 'accessor' ).then( function ( accessors ) {
  
  			var geometries = [];
  
  			for ( var i = 0, il = primitives.length; i < il; i ++ ) {
  
  				var primitive = primitives[ i ];
  
  				// See if we've already created this geometry
  				var cached = getCachedGeometry( cache, primitive );
  
  				if ( cached ) {
  
  					// Use the cached geometry if it exists
  					geometries.push( cached );
  
  				} else {
  
  					// Otherwise create a new geometry
  					var geometry = new THREE.BufferGeometry();
  
  					var attributes = primitive.attributes;
  
  					for ( var attributeId in attributes ) {
  
  						var attributeEntry = attributes[ attributeId ];
  
  						var bufferAttribute = accessors[ attributeEntry ];
  
  						switch ( attributeId ) {
  
  							case 'POSITION':
  
  								geometry.addAttribute( 'position', bufferAttribute );
  								break;
  
  							case 'NORMAL':
  
  								geometry.addAttribute( 'normal', bufferAttribute );
  								break;
  
  							case 'TEXCOORD_0':
  							case 'TEXCOORD0':
  							case 'TEXCOORD':
  
  								geometry.addAttribute( 'uv', bufferAttribute );
  								break;
  
  							case 'TEXCOORD_1':
  
  								geometry.addAttribute( 'uv2', bufferAttribute );
  								break;
  
  							case 'COLOR_0':
  							case 'COLOR0':
  							case 'COLOR':
  
  								geometry.addAttribute( 'color', bufferAttribute );
  								break;
  
  							case 'WEIGHTS_0':
  							case 'WEIGHT': // WEIGHT semantic deprecated.
  
  								geometry.addAttribute( 'skinWeight', bufferAttribute );
  								break;
  
  							case 'JOINTS_0':
  							case 'JOINT': // JOINT semantic deprecated.
  
  								geometry.addAttribute( 'skinIndex', bufferAttribute );
  								break;
  
  						}
  
  					}
  
  					if ( primitive.indices !== undefined ) {
  
  						geometry.setIndex( accessors[ primitive.indices ] );
  
  					}
  
  					// Cache this geometry
  					cache.push( {
  
  						primitive: primitive,
  						geometry: geometry
  
  					} );
  
  					geometries.push( geometry );
  
  				}
  
  			}
  
  			return geometries;
  
  		} );
  
  	};
  
  	/**
  	 * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#meshes
  	 * @param {number} meshIndex
  	 * @return {Promise<THREE.Group|THREE.Mesh|THREE.SkinnedMesh>}
  	 */
  	GLTFParser.prototype.loadMesh = function ( meshIndex ) {
  
  		var scope = this;
  		var json = this.json;
  		var extensions = this.extensions;
  
  		var meshDef = this.json.meshes[ meshIndex ];
  
  		return this.getMultiDependencies( [
  
  			'accessor',
  			'material'
  
  		] ).then( function ( dependencies ) {
  
  			var group = new THREE.Group();
  
  			var primitives = meshDef.primitives;
  
  			return scope.loadGeometries( primitives ).then( function ( geometries ) {
  
  				for ( var i = 0, il = primitives.length; i < il; i ++ ) {
  
  					var primitive = primitives[ i ];
  					var geometry = geometries[ i ];
  
  					var material = primitive.material === undefined
  						? createDefaultMaterial()
  						: dependencies.materials[ primitive.material ];
  
  					if ( material.aoMap
  							&& geometry.attributes.uv2 === undefined
  							&& geometry.attributes.uv !== undefined ) {
  
  						console.log( 'THREE.GLTFLoader: Duplicating UVs to support aoMap.' );
  						geometry.addAttribute( 'uv2', new THREE.BufferAttribute( geometry.attributes.uv.array, 2 ) );
  
  					}
  
  					// If the material will be modified later on, clone it now.
  					var useVertexColors = geometry.attributes.color !== undefined;
  					var useFlatShading = geometry.attributes.normal === undefined;
  					var useSkinning = meshDef.isSkinnedMesh === true;
  					var useMorphTargets = primitive.targets !== undefined;
  
  					if ( useVertexColors || useFlatShading || useSkinning || useMorphTargets ) {
  
  						if ( material.isGLTFSpecularGlossinessMaterial ) {
  
  							var specGlossExtension = extensions[ EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS ];
  							material = specGlossExtension.cloneMaterial( material );
  
  						} else {
  
  							material = material.clone();
  
  						}
  
  					}
  
  					if ( useVertexColors ) {
  
  						material.vertexColors = THREE.VertexColors;
  						material.needsUpdate = true;
  
  					}
  
  					if ( useFlatShading ) {
  
  						material.flatShading = true;
  
  					}
  
  					var mesh;
  
  					if ( primitive.mode === WEBGL_CONSTANTS.TRIANGLES ||
  						primitive.mode === WEBGL_CONSTANTS.TRIANGLE_STRIP ||
  						primitive.mode === WEBGL_CONSTANTS.TRIANGLE_FAN ||
  						primitive.mode === undefined ) {
  
  						if ( useSkinning ) {
  
  							mesh = new THREE.SkinnedMesh( geometry, material );
  							material.skinning = true;
  
  						} else {
  
  							mesh = new THREE.Mesh( geometry, material );
  
  						}
  
  						if ( primitive.mode === WEBGL_CONSTANTS.TRIANGLE_STRIP ) {
  
  							mesh.drawMode = THREE.TriangleStripDrawMode;
  
  						} else if ( primitive.mode === WEBGL_CONSTANTS.TRIANGLE_FAN ) {
  
  							mesh.drawMode = THREE.TriangleFanDrawMode;
  
  						}
  
  					} else if ( primitive.mode === WEBGL_CONSTANTS.LINES ) {
  
  						mesh = new THREE.LineSegments( geometry, material );
  
  					} else if ( primitive.mode === WEBGL_CONSTANTS.LINE_STRIP ) {
  
  						mesh = new THREE.Line( geometry, material );
  
  					} else if ( primitive.mode === WEBGL_CONSTANTS.LINE_LOOP ) {
  
  						mesh = new THREE.LineLoop( geometry, material );
  
  					} else if ( primitive.mode === WEBGL_CONSTANTS.POINTS ) {
  
  						mesh = new THREE.Points( geometry, material );
  
  					} else {
  
  						throw new Error( 'THREE.GLTFLoader: Primitive mode unsupported: ' + primitive.mode );
  
  					}
  
  					mesh.name = meshDef.name || ( 'mesh_' + meshIndex );
  
  					if ( useMorphTargets ) {
  
  						addMorphTargets( mesh, meshDef, primitive, dependencies.accessors );
  
  					}
  
  					if ( meshDef.extras !== undefined ) mesh.userData = meshDef.extras;
  					if ( primitive.extras !== undefined ) mesh.geometry.userData = primitive.extras;
  
  					// for Specular-Glossiness.
  					if ( material.isGLTFSpecularGlossinessMaterial === true ) {
  
  						mesh.onBeforeRender = extensions[ EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS ].refreshUniforms;
  
  					}
  
  					if ( primitives.length > 1 ) {
  
  						mesh.name += '_' + i;
  
  						group.add( mesh );
  
  					} else {
  
  						return mesh;
  
  					}
  
  				}
  
  				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' ) {
  
  			var aspectRatio = params.aspectRatio || 1;
  			var xfov = params.yfov * aspectRatio;
  
  			camera = new THREE.PerspectiveCamera( THREE.Math.radToDeg( xfov ), aspectRatio, params.znear || 1, params.zfar || 2e6 );
  
  		} else if ( cameraDef.type === 'orthographic' ) {
  
  			camera = new THREE.OrthographicCamera( params.xmag / - 2, params.xmag / 2, params.ymag / 2, params.ymag / - 2, params.znear, params.zfar );
  
  		}
  
  		if ( cameraDef.name !== undefined ) camera.name = cameraDef.name;
  		if ( cameraDef.extras ) camera.userData = cameraDef.extras;
  
  		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<THREE.AnimationClip>}
  	 */
  	GLTFParser.prototype.loadAnimation = function ( animationIndex ) {
  
  		var json = this.json;
  
  		var animationDef = this.json.animations[ animationIndex ];
  
  		return this.getMultiDependencies( [
  
  			'accessor',
  			'node'
  
  		] ).then( function ( dependencies ) {
  
  			var tracks = [];
  
  			for ( var i = 0, il = animationDef.channels.length; i < il; i ++ ) {
  
  				var channel = animationDef.channels[ i ];
  				var sampler = animationDef.samplers[ channel.sampler ];
  
  				if ( 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;
  
  					var inputAccessor = dependencies.accessors[ input ];
  					var outputAccessor = dependencies.accessors[ output ];
  
  					var node = dependencies.nodes[ name ];
  
  					if ( node ) {
  
  						node.updateMatrix();
  						node.matrixAutoUpdate = true;
  
  						var TypedKeyframeTrack;
  
  						switch ( PATH_PROPERTIES[ target.path ] ) {
  
  							case PATH_PROPERTIES.weights:
  
  								TypedKeyframeTrack = THREE.NumberKeyframeTrack;
  								break;
  
  							case PATH_PROPERTIES.rotation:
  
  								TypedKeyframeTrack = THREE.QuaternionKeyframeTrack;
  								break;
  
  							case PATH_PROPERTIES.position:
  							case PATH_PROPERTIES.scale:
  							default:
  
  								TypedKeyframeTrack = THREE.VectorKeyframeTrack;
  								break;
  
  						}
  
  						var targetName = node.name ? node.name : node.uuid;
  
  						if ( sampler.interpolation === 'CUBICSPLINE' ) {
  
  							var itemSize = outputAccessor.itemSize;
  							var TypedArray = outputAccessor.array.constructor;
  							var outputAccessorValues = new TypedArray( outputAccessor.count * itemSize / 3 );
  
  							// Layout of keyframe output values for CUBICSPLINE animations:
  							//
  							//   [ inTangent1, splineVertex1, outTangent1, inTangent2, splineVertex2, ... ]
  							//
  							// THREE.KeyframeTrack infers tangents from the spline vertices when interpolating:
  							// those values are extracted below. This still guarantees smooth curves, but does
  							// throw away more precise information in the tangents. In the future, consider
  							// re-sampling at a higher framerate using the tangents provided.
  							//
  							// See: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#appendix-c-spline-interpolation
  
  							for ( var j = 0, jl = outputAccessor.count; j < jl; j += 3 ) {
  
  								outputAccessorValues[ j * itemSize / 3 ] = outputAccessor.getX( j + 1 );
  								if ( itemSize > 1 ) outputAccessorValues[ j * itemSize / 3 + 1 ] = outputAccessor.getY( j + 1 );
  								if ( itemSize > 2 ) outputAccessorValues[ j * itemSize / 3 + 2 ] = outputAccessor.getZ( j + 1 );
  								if ( itemSize > 3 ) outputAccessorValues[ j * itemSize / 3 + 3 ] = outputAccessor.getW( j + 1 );
  
  							}
  
  							outputAccessor = new THREE.BufferAttribute( outputAccessorValues, itemSize / 3, outputAccessor.normalized );
  
  						}
  
  						var interpolation = sampler.interpolation !== undefined ? INTERPOLATION[ sampler.interpolation ] : THREE.InterpolateLinear;
  
  						var targetNames = [];
  
  						if ( PATH_PROPERTIES[ target.path ] === PATH_PROPERTIES.weights ) {
  
  							// node should be THREE.Group here but
  							// PATH_PROPERTIES.weights(morphTargetInfluences) should be
  							// the property of a mesh object under node.
  							// So finding targets here.
  
  							node.traverse( function ( object ) {
  
  								if ( object.isMesh === true && object.material.morphTargets === true ) {
  
  									targetNames.push( object.name ? object.name : object.uuid );
  
  								}
  
  							} );
  
  						} else {
  
  							targetNames.push( targetName );
  
  						}
  
  						// KeyframeTrack.optimize() will modify given 'times' and 'values'
  						// buffers before creating a truncated copy to keep. Because buffers may
  						// be reused by other tracks, make copies here.
  						for ( var j = 0, jl = targetNames.length; j < jl; j ++ ) {
  
  							tracks.push( new TypedKeyframeTrack(
  								targetNames[ j ] + '.' + PATH_PROPERTIES[ target.path ],
  								THREE.AnimationUtils.arraySlice( inputAccessor.array, 0 ),
  								THREE.AnimationUtils.arraySlice( outputAccessor.array, 0 ),
  								interpolation
  							) );
  
  						}
  
  					}
  
  				}
  
  			}
  
  			var name = animationDef.name !== undefined ? animationDef.name : 'animation_' + animationIndex;
  
  			return new THREE.AnimationClip( name, undefined, tracks );
  
  		} );
  
  	};
  
  	/**
  	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#nodes-and-hierarchy
  	 * @param {number} nodeIndex
  	 * @return {Promise<THREE.Object3D>}
  	 */
  	GLTFParser.prototype.loadNode = function ( nodeIndex ) {
  
  		var json = this.json;
  		var extensions = this.extensions;
  
  		var meshReferences = this.json.meshReferences;
  		var meshUses = this.json.meshUses;
  
  		var nodeDef = this.json.nodes[ nodeIndex ];
  
  		return this.getMultiDependencies( [
  
  			'mesh',
  			'skin',
  			'camera'
  
  		] ).then( function ( dependencies ) {
  
  			var node;
  
  			if ( nodeDef.isBone === true ) {
  
  				node = new THREE.Bone();
  
  			} else if ( nodeDef.mesh !== undefined ) {
  
  				var mesh = dependencies.meshes[ nodeDef.mesh ];
  
  				node = mesh.clone();
  
  				// for Specular-Glossiness
  				if ( mesh.isGroup === true ) {
  
  					for ( var i = 0, il = mesh.children.length; i < il; i ++ ) {
  
  						var child = mesh.children[ i ];
  
  						if ( child.material && child.material.isGLTFSpecularGlossinessMaterial === true ) {
  
  							node.children[ i ].onBeforeRender = child.onBeforeRender;
  
  						}
  
  					}
  
  				} else {
  
  					if ( mesh.material && mesh.material.isGLTFSpecularGlossinessMaterial === true ) {
  
  						node.onBeforeRender = mesh.onBeforeRender;
  
  					}
  
  				}
  
  				if ( meshReferences[ nodeDef.mesh ] > 1 ) {
  
  					node.name += '_instance_' + meshUses[ nodeDef.mesh ] ++;
  
  				}
  
  			} else if ( nodeDef.camera !== undefined ) {
  
  				node = dependencies.cameras[ nodeDef.camera ];
  
  			} else if ( nodeDef.extensions
  					 && nodeDef.extensions[ EXTENSIONS.KHR_LIGHTS ]
  					 && nodeDef.extensions[ EXTENSIONS.KHR_LIGHTS ].light !== undefined ) {
  
  				var lights = extensions[ EXTENSIONS.KHR_LIGHTS ].lights;
  				node = lights[ nodeDef.extensions[ EXTENSIONS.KHR_LIGHTS ].light ];
  
  			} else {
  
  				node = new THREE.Object3D();
  
  			}
  
  			if ( nodeDef.name !== undefined ) {
  
  				node.name = THREE.PropertyBinding.sanitizeNodeName( nodeDef.name );
  
  			}
  
  			if ( nodeDef.extras ) node.userData = nodeDef.extras;
  
  			if ( nodeDef.matrix !== undefined ) {
  
  				var matrix = new THREE.Matrix4();
  				matrix.fromArray( nodeDef.matrix );
  				node.applyMatrix( 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 );
  
  				}
  
  			}
  
  			return node;
  
  		} );
  
  	};
  
  	/**
  	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#scenes
  	 * @param {number} sceneIndex
  	 * @return {Promise<THREE.Scene>}
  	 */
  	GLTFParser.prototype.loadScene = function () {
  
  		// scene node hierachy builder
  
  		function buildNodeHierachy( nodeId, parentObject, json, allNodes, skins ) {
  
  			var node = allNodes[ nodeId ];
  			var nodeDef = json.nodes[ nodeId ];
  
  			// build skeleton here as well
  
  			if ( nodeDef.skin !== undefined ) {
  
  				var meshes = node.isGroup === true ? node.children : [ node ];
  
  				for ( var i = 0, il = meshes.length; i < il; i ++ ) {
  
  					var mesh = meshes[ i ];
  					var skinEntry = skins[ nodeDef.skin ];
  
  					var bones = [];
  					var boneInverses = [];
  
  					for ( var j = 0, jl = skinEntry.joints.length; j < jl; j ++ ) {
  
  						var jointId = skinEntry.joints[ j ];
  						var jointNode = allNodes[ jointId ];
  
  						if ( jointNode ) {
  
  							bones.push( jointNode );
  
  							var mat = new THREE.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.', jointId );
  
  						}
  
  					}
  
  					mesh.bind( new THREE.Skeleton( bones, boneInverses ), mesh.matrixWorld );
  
  				}
  
  			}
  
  			// build node hierachy
  
  			parentObject.add( node );
  
  			if ( nodeDef.children ) {
  
  				var children = nodeDef.children;
  
  				for ( var i = 0, il = children.length; i < il; i ++ ) {
  
  					var child = children[ i ];
  					buildNodeHierachy( child, node, json, allNodes, skins );
  
  				}
  
  			}
  
  		}
  
  		return function loadScene( sceneIndex ) {
  
  			var json = this.json;
  			var extensions = this.extensions;
  			var sceneDef = this.json.scenes[ sceneIndex ];
  
  			return this.getMultiDependencies( [
  
  				'node',
  				'skin'
  
  			] ).then( function ( dependencies ) {
  
  				var scene = new THREE.Scene();
  				if ( sceneDef.name !== undefined ) scene.name = sceneDef.name;
  
  				if ( sceneDef.extras ) scene.userData = sceneDef.extras;
  
  				var nodeIds = sceneDef.nodes || [];
  
  				for ( var i = 0, il = nodeIds.length; i < il; i ++ ) {
  
  					buildNodeHierachy( nodeIds[ i ], scene, json, dependencies.nodes, dependencies.skins );
  
  				}
  
  				// Ambient lighting, if present, is always attached to the scene root.
  				if ( sceneDef.extensions
  						 && sceneDef.extensions[ EXTENSIONS.KHR_LIGHTS ]
  						 && sceneDef.extensions[ EXTENSIONS.KHR_LIGHTS ].light !== undefined ) {
  
  					var lights = extensions[ EXTENSIONS.KHR_LIGHTS ].lights;
  					scene.add( lights[ sceneDef.extensions[ EXTENSIONS.KHR_LIGHTS ].light ] );
  
  				}
  
  				return scene;
  
  			} );
  
  		};
  
  	}();
  
  	return GLTFLoader;
  
  } )();
  