three#InterleavedBufferAttribute JavaScript Examples

The following examples show how to use three#InterleavedBufferAttribute. You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example. You may check out the related API usage on the sidebar.
Example #1
Source File: LineSegments2.js    From BlueMapWeb with MIT License 4 votes vote down vote up
LineSegments2.prototype = Object.assign( Object.create( Mesh.prototype ), {

	constructor: LineSegments2,

	isLineSegments2: true,

	computeLineDistances: ( function () { // for backwards-compatability, but could be a method of LineSegmentsGeometry...

		var start = new Vector3();
		var end = new Vector3();

		return function computeLineDistances() {

			var geometry = this.geometry;

			var instanceStart = geometry.attributes.instanceStart;
			var instanceEnd = geometry.attributes.instanceEnd;
			var lineDistances = new Float32Array( 2 * instanceStart.data.count );

			for ( var i = 0, j = 0, l = instanceStart.data.count; i < l; i ++, j += 2 ) {

				start.fromBufferAttribute( instanceStart, i );
				end.fromBufferAttribute( instanceEnd, i );

				lineDistances[ j ] = ( j === 0 ) ? 0 : lineDistances[ j - 1 ];
				lineDistances[ j + 1 ] = lineDistances[ j ] + start.distanceTo( end );

			}

			var instanceDistanceBuffer = new InstancedInterleavedBuffer( lineDistances, 2, 1 ); // d0, d1

			geometry.setAttribute( 'instanceDistanceStart', new InterleavedBufferAttribute( instanceDistanceBuffer, 1, 0 ) ); // d0
			geometry.setAttribute( 'instanceDistanceEnd', new InterleavedBufferAttribute( instanceDistanceBuffer, 1, 1 ) ); // d1

			return this;

		};

	}() ),

	raycast: ( function () {

		var start = new Vector4();
		var end = new Vector4();

		var ssOrigin = new Vector4();
		var ssOrigin3 = new Vector3();
		var mvMatrix = new Matrix4();
		var line = new Line3();
		var closestPoint = new Vector3();

		return function raycast( raycaster, intersects ) {

			if ( raycaster.camera === null ) {

				console.error( 'LineSegments2: "Raycaster.camera" needs to be set in order to raycast against LineSegments2.' );

			}

			var threshold = ( raycaster.params.Line2 !== undefined ) ? raycaster.params.Line2.threshold || 0 : 0;

			var ray = raycaster.ray;
			var camera = raycaster.camera;
			var projectionMatrix = camera.projectionMatrix;

			var geometry = this.geometry;
			var material = this.material;
			var resolution = material.resolution;
			var lineWidth = material.linewidth + threshold;

			var instanceStart = geometry.attributes.instanceStart;
			var instanceEnd = geometry.attributes.instanceEnd;

			// pick a point 1 unit out along the ray to avoid the ray origin
			// sitting at the camera origin which will cause "w" to be 0 when
			// applying the projection matrix.
			ray.at( 1, ssOrigin );

			// ndc space [ - 1.0, 1.0 ]
			ssOrigin.w = 1;
			ssOrigin.applyMatrix4( camera.matrixWorldInverse );
			ssOrigin.applyMatrix4( projectionMatrix );
			ssOrigin.multiplyScalar( 1 / ssOrigin.w );

			// screen space
			ssOrigin.x *= resolution.x / 2;
			ssOrigin.y *= resolution.y / 2;
			ssOrigin.z = 0;

			ssOrigin3.copy( ssOrigin );

			var matrixWorld = this.matrixWorld;
			mvMatrix.multiplyMatrices( camera.matrixWorldInverse, matrixWorld );

			for ( var i = 0, l = instanceStart.count; i < l; i ++ ) {

				start.fromBufferAttribute( instanceStart, i );
				end.fromBufferAttribute( instanceEnd, i );

				start.w = 1;
				end.w = 1;

				// camera space
				start.applyMatrix4( mvMatrix );
				end.applyMatrix4( mvMatrix );

				// clip space
				start.applyMatrix4( projectionMatrix );
				end.applyMatrix4( projectionMatrix );

				// ndc space [ - 1.0, 1.0 ]
				start.multiplyScalar( 1 / start.w );
				end.multiplyScalar( 1 / end.w );

				// skip the segment if it's outside the camera near and far planes
				var isBehindCameraNear = start.z < - 1 && end.z < - 1;
				var isPastCameraFar = start.z > 1 && end.z > 1;
				if ( isBehindCameraNear || isPastCameraFar ) {

					continue;

				}

				// screen space
				start.x *= resolution.x / 2;
				start.y *= resolution.y / 2;

				end.x *= resolution.x / 2;
				end.y *= resolution.y / 2;

				// create 2d segment
				line.start.copy( start );
				line.start.z = 0;

				line.end.copy( end );
				line.end.z = 0;

				// get closest point on ray to segment
				var param = line.closestPointToPointParameter( ssOrigin3, true );
				line.at( param, closestPoint );

				// check if the intersection point is within clip space
				var zPos = MathUtils.lerp( start.z, end.z, param );
				var isInClipSpace = zPos >= - 1 && zPos <= 1;

				var isInside = ssOrigin3.distanceTo( closestPoint ) < lineWidth * 0.5;

				if ( isInClipSpace && isInside ) {

					line.start.fromBufferAttribute( instanceStart, i );
					line.end.fromBufferAttribute( instanceEnd, i );

					line.start.applyMatrix4( matrixWorld );
					line.end.applyMatrix4( matrixWorld );

					var pointOnLine = new Vector3();
					var point = new Vector3();

					ray.distanceSqToSegment( line.start, line.end, point, pointOnLine );

					intersects.push( {

						point: point,
						pointOnLine: pointOnLine,
						distance: ray.origin.distanceTo( point ),

						object: this,
						face: null,
						faceIndex: i,
						uv: null,
						uv2: null,

					} );

				}

			}

		};

	}() )

} );
Example #2
Source File: LineSegmentsGeometry.js    From BlueMapWeb with MIT License 4 votes vote down vote up
LineSegmentsGeometry.prototype = Object.assign( Object.create( InstancedBufferGeometry.prototype ), {

	constructor: LineSegmentsGeometry,

	isLineSegmentsGeometry: true,

	applyMatrix4: function ( matrix ) {

		var start = this.attributes.instanceStart;
		var end = this.attributes.instanceEnd;

		if ( start !== undefined ) {

			start.applyMatrix4( matrix );

			end.applyMatrix4( matrix );

			start.needsUpdate = true;

		}

		if ( this.boundingBox !== null ) {

			this.computeBoundingBox();

		}

		if ( this.boundingSphere !== null ) {

			this.computeBoundingSphere();

		}

		return this;

	},

	setPositions: function ( array ) {

		var lineSegments;

		if ( array instanceof Float32Array ) {

			lineSegments = array;

		} else if ( Array.isArray( array ) ) {

			lineSegments = new Float32Array( array );

		}

		var instanceBuffer = new InstancedInterleavedBuffer( lineSegments, 6, 1 ); // xyz, xyz

		this.setAttribute( 'instanceStart', new InterleavedBufferAttribute( instanceBuffer, 3, 0 ) ); // xyz
		this.setAttribute( 'instanceEnd', new InterleavedBufferAttribute( instanceBuffer, 3, 3 ) ); // xyz

		//

		this.computeBoundingBox();
		this.computeBoundingSphere();

		return this;

	},

	setColors: function ( array ) {

		var colors;

		if ( array instanceof Float32Array ) {

			colors = array;

		} else if ( Array.isArray( array ) ) {

			colors = new Float32Array( array );

		}

		var instanceColorBuffer = new InstancedInterleavedBuffer( colors, 6, 1 ); // rgb, rgb

		this.setAttribute( 'instanceColorStart', new InterleavedBufferAttribute( instanceColorBuffer, 3, 0 ) ); // rgb
		this.setAttribute( 'instanceColorEnd', new InterleavedBufferAttribute( instanceColorBuffer, 3, 3 ) ); // rgb

		return this;

	},

	fromWireframeGeometry: function ( geometry ) {

		this.setPositions( geometry.attributes.position.array );

		return this;

	},

	fromEdgesGeometry: function ( geometry ) {

		this.setPositions( geometry.attributes.position.array );

		return this;

	},

	fromMesh: function ( mesh ) {

		this.fromWireframeGeometry( new WireframeGeometry( mesh.geometry ) );

		// set colors, maybe

		return this;

	},

	fromLineSegments: function ( lineSegments ) {

		var geometry = lineSegments.geometry;

		if ( geometry.isGeometry ) {

			this.setPositions( geometry.vertices );

		} else if ( geometry.isBufferGeometry ) {

			this.setPositions( geometry.attributes.position.array ); // assumes non-indexed

		}

		// set colors, maybe

		return this;

	},

	computeBoundingBox: function () {

		var box = new Box3();

		return function computeBoundingBox() {

			if ( this.boundingBox === null ) {

				this.boundingBox = new Box3();

			}

			var start = this.attributes.instanceStart;
			var end = this.attributes.instanceEnd;

			if ( start !== undefined && end !== undefined ) {

				this.boundingBox.setFromBufferAttribute( start );

				box.setFromBufferAttribute( end );

				this.boundingBox.union( box );

			}

		};

	}(),

	computeBoundingSphere: function () {

		var vector = new Vector3();

		return function computeBoundingSphere() {

			if ( this.boundingSphere === null ) {

				this.boundingSphere = new Sphere();

			}

			if ( this.boundingBox === null ) {

				this.computeBoundingBox();

			}

			var start = this.attributes.instanceStart;
			var end = this.attributes.instanceEnd;

			if ( start !== undefined && end !== undefined ) {

				var center = this.boundingSphere.center;

				this.boundingBox.getCenter( center );

				var maxRadiusSq = 0;

				for ( var i = 0, il = start.count; i < il; i ++ ) {

					vector.fromBufferAttribute( start, i );
					maxRadiusSq = Math.max( maxRadiusSq, center.distanceToSquared( vector ) );

					vector.fromBufferAttribute( end, i );
					maxRadiusSq = Math.max( maxRadiusSq, center.distanceToSquared( vector ) );

				}

				this.boundingSphere.radius = Math.sqrt( maxRadiusSq );

				if ( isNaN( this.boundingSphere.radius ) ) {

					console.error( 'THREE.LineSegmentsGeometry.computeBoundingSphere(): Computed radius is NaN. The instanced position data is likely to have NaN values.', this );

				}

			}

		};

	}(),

	toJSON: function () {

	},

	applyMatrix: function ( matrix ) {

		console.warn( 'THREE.LineSegmentsGeometry: applyMatrix() has been renamed to applyMatrix4().' );

		return this.applyMatrix4( matrix );

	}

} );
Example #3
Source File: GLTFLoader.js    From canvas with Apache License 2.0 4 votes vote down vote up
GLTFLoader = ( function () {

	function GLTFLoader( manager ) {

		Loader.call( this, manager );

		this.dracoLoader = null;
		this.ddsLoader = null;

	}

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

		constructor: GLTFLoader,

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

			var scope = this;

			var resourcePath;

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

				resourcePath = this.resourcePath;

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

				resourcePath = this.path;

			} else {

				resourcePath = LoaderUtils.extractUrlBase( url );

			}

			// Tells the LoadingManager to track an extra item, which resolves after
			// the model is fully loaded. This means the count of items loaded will
			// be incorrect, but ensures manager.onLoad() does not fire early.
			scope.manager.itemStart( url );

			var _onError = function ( e ) {

				if ( onError ) {

					onError( e );

				} else {

					console.error( e );

				}

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

			};

			var loader = new FileLoader( scope.manager );

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

			if ( scope.crossOrigin === 'use-credentials' ) {

				loader.setWithCredentials( true );

			}

			loader.load( url, function ( data ) {

				try {

					scope.parse( data, resourcePath, function ( gltf ) {

						onLoad( gltf );

						scope.manager.itemEnd( url );

					}, _onError );

				} catch ( e ) {

					_onError( e );

				}

			}, onProgress, _onError );

		},

		setDRACOLoader: function ( dracoLoader ) {

			this.dracoLoader = dracoLoader;
			return this;

		},

		setDDSLoader: function ( ddsLoader ) {

			this.ddsLoader = ddsLoader;
			return this;

		},

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

			var content;
			var extensions = {};

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

				content = data;

			} else {

				var magic = LoaderUtils.decodeText( new Uint8Array( data, 0, 4 ) );

				if ( magic === BINARY_EXTENSION_HEADER_MAGIC ) {

					try {

						extensions[ EXTENSIONS.KHR_BINARY_GLTF ] = new GLTFBinaryExtension( data );

					} catch ( error ) {

						if ( onError ) onError( error );
						return;

					}

					content = extensions[ EXTENSIONS.KHR_BINARY_GLTF ].content;

				} else {

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

				}

			}

			var json = JSON.parse( content );

			if ( json.asset === undefined || json.asset.version[ 0 ] < 2 ) {

				if ( onError ) onError( new Error( 'THREE.GLTFLoader: Unsupported asset. glTF versions >=2.0 are supported.' ) );
				return;

			}

			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_CLEARCOAT:
							extensions[ extensionName ] = new GLTFMaterialsClearcoatExtension();
							break;

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

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

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

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

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

						case EXTENSIONS.KHR_MESH_QUANTIZATION:
							extensions[ extensionName ] = new GLTFMeshQuantizationExtension();
							break;

						default:

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

								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( onLoad, onError );

		}

	} );

	/* GLTFREGISTRY */

	function GLTFRegistry() {

		var objects = {};

		return	{

			get: function ( key ) {

				return objects[ key ];

			},

			add: function ( key, object ) {

				objects[ key ] = object;

			},

			remove: function ( key ) {

				delete objects[ key ];

			},

			removeAll: function () {

				objects = {};

			}

		};

	}

	/*********************************/
	/********** EXTENSIONS ***********/
	/*********************************/

	var EXTENSIONS = {
		KHR_BINARY_GLTF: 'KHR_binary_glTF',
		KHR_DRACO_MESH_COMPRESSION: 'KHR_draco_mesh_compression',
		KHR_LIGHTS_PUNCTUAL: 'KHR_lights_punctual',
		KHR_MATERIALS_CLEARCOAT: 'KHR_materials_clearcoat',
		KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS: 'KHR_materials_pbrSpecularGlossiness',
		KHR_MATERIALS_UNLIT: 'KHR_materials_unlit',
		KHR_TEXTURE_TRANSFORM: 'KHR_texture_transform',
		KHR_MESH_QUANTIZATION: 'KHR_mesh_quantization',
		MSFT_TEXTURE_DDS: 'MSFT_texture_dds'
	};

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

		if ( ! ddsLoader ) {

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

		}

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

	}

	/**
	 * Punctual Lights Extension
	 *
	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_lights_punctual
	 */
	function GLTFLightsExtension( 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 Color( 0xffffff );
		if ( lightDef.color !== undefined ) color.fromArray( lightDef.color );

		var range = lightDef.range !== undefined ? lightDef.range : 0;

		switch ( lightDef.type ) {

			case 'directional':
				lightNode = new DirectionalLight( color );
				lightNode.target.position.set( 0, 0, - 1 );
				lightNode.add( lightNode.target );
				break;

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

			case 'spot':
				lightNode = new SpotLight( color );
				lightNode.distance = range;
				// Handle spotlight properties.
				lightDef.spot = lightDef.spot || {};
				lightDef.spot.innerConeAngle = lightDef.spot.innerConeAngle !== undefined ? lightDef.spot.innerConeAngle : 0;
				lightDef.spot.outerConeAngle = lightDef.spot.outerConeAngle !== undefined ? lightDef.spot.outerConeAngle : Math.PI / 4.0;
				lightNode.angle = lightDef.spot.outerConeAngle;
				lightNode.penumbra = 1.0 - lightDef.spot.innerConeAngle / lightDef.spot.outerConeAngle;
				lightNode.target.position.set( 0, 0, - 1 );
				lightNode.add( lightNode.target );
				break;

			default:
				throw new Error( 'THREE.GLTFLoader: Unexpected light type, "' + lightDef.type + '".' );

		}

		// Some lights (e.g. spot) default to a position other than the origin. Reset the position
		// here, because node-level parsing will only override position if explicitly specified.
		lightNode.position.set( 0, 0, 0 );

		lightNode.decay = 2;

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

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

		return Promise.resolve( lightNode );

	};

	/**
	 * Unlit Materials Extension
	 *
	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_materials_unlit
	 */
	function GLTFMaterialsUnlitExtension() {

		this.name = EXTENSIONS.KHR_MATERIALS_UNLIT;

	}

	GLTFMaterialsUnlitExtension.prototype.getMaterialType = function () {

		return MeshBasicMaterial;

	};

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

		var pending = [];

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

		var metallicRoughness = materialDef.pbrMetallicRoughness;

		if ( metallicRoughness ) {

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

				var array = metallicRoughness.baseColorFactor;

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

			}

			if ( metallicRoughness.baseColorTexture !== undefined ) {

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

			}

		}

		return Promise.all( pending );

	};

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

		this.name = EXTENSIONS.KHR_MATERIALS_CLEARCOAT;

	}

	GLTFMaterialsClearcoatExtension.prototype.getMaterialType = function () {

		return MeshPhysicalMaterial;

	};

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

		var pending = [];

		var extension = materialDef.extensions[ this.name ];

		if ( extension.clearcoatFactor !== undefined ) {

			materialParams.clearcoat = extension.clearcoatFactor;

		}

		if ( extension.clearcoatTexture !== undefined ) {

			pending.push( parser.assignTexture( materialParams, 'clearcoatMap', extension.clearcoatTexture ) );

		}

		if ( extension.clearcoatRoughnessFactor !== undefined ) {

			materialParams.clearcoatRoughness = extension.clearcoatRoughnessFactor;

		}

		if ( extension.clearcoatRoughnessTexture !== undefined ) {

			pending.push( parser.assignTexture( materialParams, 'clearcoatRoughnessMap', extension.clearcoatRoughnessTexture ) );

		}

		if ( extension.clearcoatNormalTexture !== undefined ) {

			pending.push( parser.assignTexture( materialParams, 'clearcoatNormalMap', extension.clearcoatNormalTexture ) );

			if ( extension.clearcoatNormalTexture.scale !== undefined ) {

				var scale = extension.clearcoatNormalTexture.scale;

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

			}

		}

		return Promise.all( pending );

	};

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

	function GLTFBinaryExtension( data ) {

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

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

		this.header = {
			magic: LoaderUtils.decodeText( new Uint8Array( data.slice( 0, 4 ) ) ),
			version: headerView.getUint32( 4, true ),
			length: headerView.getUint32( 8, true )
		};

		if ( this.header.magic !== BINARY_EXTENSION_HEADER_MAGIC ) {

			throw new Error( 'THREE.GLTFLoader: Unsupported glTF-Binary header.' );

		} else if ( this.header.version < 2.0 ) {

			throw new Error( 'THREE.GLTFLoader: Legacy binary file detected.' );

		}

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

		while ( chunkIndex < chunkView.byteLength ) {

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

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

			if ( chunkType === BINARY_EXTENSION_CHUNK_TYPES.JSON ) {

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

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

				var byteOffset = BINARY_EXTENSION_HEADER_LENGTH + chunkIndex;
				this.body = data.slice( byteOffset, byteOffset + chunkLength );

			}

			// Clients must ignore chunks with unknown types.

			chunkIndex += chunkLength;

		}

		if ( this.content === null ) {

			throw new Error( 'THREE.GLTFLoader: JSON content not found.' );

		}

	}

	/**
	 * DRACO Mesh Compression Extension
	 *
	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_draco_mesh_compression
	 */
	function GLTFDracoMeshCompressionExtension( json, dracoLoader ) {

		if ( ! dracoLoader ) {

			throw new Error( 'THREE.GLTFLoader: No DRACOLoader instance provided.' );

		}

		this.name = EXTENSIONS.KHR_DRACO_MESH_COMPRESSION;
		this.json = json;
		this.dracoLoader = dracoLoader;
		this.dracoLoader.preload();

	}

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

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

		for ( var attributeName in gltfAttributeMap ) {

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

			threeAttributeMap[ threeAttributeName ] = gltfAttributeMap[ attributeName ];

		}

		for ( attributeName in primitive.attributes ) {

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

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

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

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

			}

		}

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

			return new Promise( function ( resolve ) {

				dracoLoader.decodeDracoFile( bufferView, function ( geometry ) {

					for ( var attributeName in geometry.attributes ) {

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

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

					}

					resolve( geometry );

				}, threeAttributeMap, attributeTypeMap );

			} );

		} );

	};

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

		this.name = EXTENSIONS.KHR_TEXTURE_TRANSFORM;

	}

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

		texture = texture.clone();

		if ( transform.offset !== undefined ) {

			texture.offset.fromArray( transform.offset );

		}

		if ( transform.rotation !== undefined ) {

			texture.rotation = transform.rotation;

		}

		if ( transform.scale !== undefined ) {

			texture.repeat.fromArray( transform.scale );

		}

		if ( transform.texCoord !== undefined ) {

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

		}

		texture.needsUpdate = true;

		return texture;

	};

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

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

	function GLTFMeshStandardSGMaterial( params ) {

		MeshStandardMaterial.call( this );

		this.isGLTFSpecularGlossinessMaterial = true;

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

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

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

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

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

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

		this._extraUniforms = uniforms;

		// please see #14031 or #13198 for an alternate approach
		this.onBeforeCompile = function ( shader ) {

			for ( var uniformName in uniforms ) {

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

			}

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

		};

		/*eslint-disable*/
		Object.defineProperties(
			this,
			{
				specular: {
					get: function () { return uniforms.specular.value; },
					set: function ( v ) { uniforms.specular.value = v; }
				},
				specularMap: {
					get: function () { return uniforms.specularMap.value; },
					set: function ( v ) { uniforms.specularMap.value = v; }
				},
				glossiness: {
					get: function () { return uniforms.glossiness.value; },
					set: function ( v ) { uniforms.glossiness.value = v; }
				},
				glossinessMap: {
					get: function () { return uniforms.glossinessMap.value; },
					set: function ( v ) {

						uniforms.glossinessMap.value = v;
						//how about something like this - @pailhead
						if ( v ) {

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

						} else {

							delete this.defines.USE_ROUGHNESSMAP;
							delete this.defines.USE_GLOSSINESSMAP;

						}

					}
				}
			}
		);

		/*eslint-enable*/
		delete this.metalness;
		delete this.roughness;
		delete this.metalnessMap;
		delete this.roughnessMap;

		this.setValues( params );

	}

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

	GLTFMeshStandardSGMaterial.prototype.copy = function ( source ) {

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

	};

	function GLTFMaterialsPbrSpecularGlossinessExtension() {

		return {

			name: EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS,

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

			getMaterialType: function () {

				return GLTFMeshStandardSGMaterial;

			},

			extendParams: function ( materialParams, materialDef, parser ) {

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

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

				var pending = [];

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

					var array = pbrSpecularGlossiness.diffuseFactor;

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

				}

				if ( pbrSpecularGlossiness.diffuseTexture !== undefined ) {

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

				}

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

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

					materialParams.specular.fromArray( pbrSpecularGlossiness.specularFactor );

				}

				if ( pbrSpecularGlossiness.specularGlossinessTexture !== undefined ) {

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

				}

				return Promise.all( pending );

			},

			createMaterial: function ( materialParams ) {

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

				material.color = materialParams.color;

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

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

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

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

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

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

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

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

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

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

				material.alphaMap = null;

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

				material.refractionRatio = 0.98;

				return material;

			},

		};

	}

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

		this.name = EXTENSIONS.KHR_MESH_QUANTIZATION;

	}

	/*********************************/
	/********** INTERPOLATION ********/
	/*********************************/

	// Spline Interpolation
	// Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#appendix-c-spline-interpolation
	function GLTFCubicSplineInterpolant( parameterPositions, sampleValues, sampleSize, resultBuffer ) {

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

	}

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

	GLTFCubicSplineInterpolant.prototype.copySampleValue_ = function ( index ) {

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

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

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

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

		}

		return result;

	};

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

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

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

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

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

		var td = t1 - t0;

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

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

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

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

			var p0 = values[ offset0 + i + stride ]; // splineVertex_k
			var m0 = values[ offset0 + i + stride2 ] * td; // outTangent_k * (t_k+1 - t_k)
			var p1 = values[ offset1 + i + stride ]; // splineVertex_k+1
			var m1 = values[ offset1 + i ] * td; // inTangent_k+1 * (t_k+1 - t_k)

			result[ i ] = s0 * p0 + s1 * m0 + s2 * p1 + s3 * m1;

		}

		return result;

	};

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

	/* CONSTANTS */

	var WEBGL_CONSTANTS = {
		FLOAT: 5126,
		//FLOAT_MAT2: 35674,
		FLOAT_MAT3: 35675,
		FLOAT_MAT4: 35676,
		FLOAT_VEC2: 35664,
		FLOAT_VEC3: 35665,
		FLOAT_VEC4: 35666,
		LINEAR: 9729,
		REPEAT: 10497,
		SAMPLER_2D: 35678,
		POINTS: 0,
		LINES: 1,
		LINE_LOOP: 2,
		LINE_STRIP: 3,
		TRIANGLES: 4,
		TRIANGLE_STRIP: 5,
		TRIANGLE_FAN: 6,
		UNSIGNED_BYTE: 5121,
		UNSIGNED_SHORT: 5123
	};

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

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

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

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

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

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

	var INTERPOLATION = {
		CUBICSPLINE: undefined, // We use a custom interpolant (GLTFCubicSplineInterpolation) for CUBICSPLINE tracks. Each
		                        // keyframe track will be initialized with a default interpolation type, then modified.
		LINEAR: InterpolateLinear,
		STEP: InterpolateDiscrete
	};

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

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

	/* UTILITY FUNCTIONS */

	function resolveURL( url, path ) {

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

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

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

		}

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

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

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

		// Relative URL
		return path + url;

	}

	/**
	 * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#default-material
	 */
	function createDefaultMaterial( cache ) {

		if ( cache[ 'DefaultMaterial' ] === undefined ) {

			cache[ 'DefaultMaterial' ] = new MeshStandardMaterial( {
				color: 0xFFFFFF,
				emissive: 0x000000,
				metalness: 1,
				roughness: 1,
				transparent: false,
				depthTest: true,
				side: FrontSide
			} );

		}

		return cache[ 'DefaultMaterial' ];

	}

	function addUnknownExtensionsToUserData( knownExtensions, object, objectDef ) {

		// Add unknown glTF extensions to an object's userData.

		for ( var name in objectDef.extensions ) {

			if ( knownExtensions[ name ] === undefined ) {

				object.userData.gltfExtensions = object.userData.gltfExtensions || {};
				object.userData.gltfExtensions[ name ] = objectDef.extensions[ name ];

			}

		}

	}

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

		if ( gltfDef.extras !== undefined ) {

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

				Object.assign( object.userData, gltfDef.extras );

			} else {

				console.warn( 'THREE.GLTFLoader: Ignoring primitive type .extras, ' + gltfDef.extras );

			}

		}

	}

	/**
	 * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#morph-targets
	 *
	 * @param {BufferGeometry} geometry
	 * @param {Array<GLTF.Target>} targets
	 * @param {GLTFParser} parser
	 * @return {Promise<BufferGeometry>}
	 */
	function addMorphTargets( geometry, targets, parser ) {

		var hasMorphPosition = false;
		var hasMorphNormal = false;

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

			var target = targets[ i ];

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

			if ( hasMorphPosition && hasMorphNormal ) break;

		}

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

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

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

			var target = targets[ i ];

			if ( hasMorphPosition ) {

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

				pendingPositionAccessors.push( pendingAccessor );

			}

			if ( hasMorphNormal ) {

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

				pendingNormalAccessors.push( pendingAccessor );

			}

		}

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

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

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

			return geometry;

		} );

	}

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

		mesh.updateMorphTargets();

		if ( meshDef.weights !== undefined ) {

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

				mesh.morphTargetInfluences[ i ] = meshDef.weights[ i ];

			}

		}

		// .extras has user-defined data, so check that .extras.targetNames is an array.
		if ( meshDef.extras && Array.isArray( meshDef.extras.targetNames ) ) {

			var targetNames = meshDef.extras.targetNames;

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

				mesh.morphTargetDictionary = {};

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

					mesh.morphTargetDictionary[ targetNames[ i ] ] = i;

				}

			} else {

				console.warn( 'THREE.GLTFLoader: Invalid extras.targetNames length. Ignoring names.' );

			}

		}

	}

	function createPrimitiveKey( primitiveDef ) {

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

		if ( dracoExtension ) {

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

		} else {

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

		}

		return geometryKey;

	}

	function createAttributesKey( attributes ) {

		var attributesKey = '';

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

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

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

		}

		return attributesKey;

	}

	/* GLTF PARSER */

	function GLTFParser( json, 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 TextureLoader( this.options.manager );
		this.textureLoader.setCrossOrigin( this.options.crossOrigin );

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

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

			this.fileLoader.setWithCredentials( true );

		}

	}

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

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

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

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

		Promise.all( [

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

		] ).then( function ( dependencies ) {

			var result = {
				scene: dependencies[ 0 ][ json.scene || 0 ],
				scenes: dependencies[ 0 ],
				animations: dependencies[ 1 ],
				cameras: dependencies[ 2 ],
				asset: json.asset,
				parser: parser,
				userData: {}
			};

			addUnknownExtensionsToUserData( extensions, result, json );

			assignExtrasToUserData( result, json );

			onLoad( result );

		} ).catch( onError );

	};

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

		var nodeDefs = this.json.nodes || [];
		var skinDefs = this.json.skins || [];
		var meshDefs = this.json.meshes || [];

		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 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<Object3D|Material|THREE.Texture|AnimationClip|ArrayBuffer|Object>}
	 */
	GLTFParser.prototype.getDependency = function ( type, index ) {

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

		if ( ! dependency ) {

			switch ( type ) {

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

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

				case 'mesh':
					dependency = this.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;

	};

	/**
	 * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#buffers-and-buffer-views
	 * @param {number} bufferIndex
	 * @return {Promise<ArrayBuffer>}
	 */
	GLTFParser.prototype.loadBuffer = function ( bufferIndex ) {

		var bufferDef = this.json.buffers[ bufferIndex ];
		var loader = this.fileLoader;

		if ( bufferDef.type && bufferDef.type !== 'arraybuffer' ) {

			throw new Error( 'THREE.GLTFLoader: ' + bufferDef.type + ' buffer type is not supported.' );

		}

		// If present, GLB container is required to be the first buffer.
		if ( bufferDef.uri === undefined && bufferIndex === 0 ) {

			return Promise.resolve( this.extensions[ EXTENSIONS.KHR_BINARY_GLTF ].body );

		}

		var options = this.options;

		return new Promise( function ( resolve, reject ) {

			loader.load( resolveURL( bufferDef.uri, options.path ), resolve, undefined, function () {

				reject( new Error( 'THREE.GLTFLoader: Failed to load buffer "' + bufferDef.uri + '".' ) );

			} );

		} );

	};

	/**
	 * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#buffers-and-buffer-views
	 * @param {number} bufferViewIndex
	 * @return {Promise<ArrayBuffer>}
	 */
	GLTFParser.prototype.loadBufferView = function ( bufferViewIndex ) {

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

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

			var byteLength = bufferViewDef.byteLength || 0;
			var byteOffset = bufferViewDef.byteOffset || 0;
			return buffer.slice( byteOffset, byteOffset + byteLength );

		} );

	};

	/**
	 * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#accessors
	 * @param {number} accessorIndex
	 * @return {Promise<BufferAttribute|InterleavedBufferAttribute>}
	 */
	GLTFParser.prototype.loadAccessor = function ( accessorIndex ) {

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

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

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

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

		}

		var pendingBufferViews = [];

		if ( accessorDef.bufferView !== undefined ) {

			pendingBufferViews.push( this.getDependency( 'bufferView', accessorDef.bufferView ) );

		} else {

			pendingBufferViews.push( null );

		}

		if ( accessorDef.sparse !== undefined ) {

			pendingBufferViews.push( this.getDependency( 'bufferView', accessorDef.sparse.indices.bufferView ) );
			pendingBufferViews.push( this.getDependency( 'bufferView', accessorDef.sparse.values.bufferView ) );

		}

		return Promise.all( pendingBufferViews ).then( function ( bufferViews ) {

			var bufferView = bufferViews[ 0 ];

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

			// For VEC3: itemSize is 3, elementBytes is 4, itemBytes is 12.
			var elementBytes = TypedArray.BYTES_PER_ELEMENT;
			var itemBytes = elementBytes * itemSize;
			var byteOffset = accessorDef.byteOffset || 0;
			var byteStride = accessorDef.bufferView !== undefined ? json.bufferViews[ accessorDef.bufferView ].byteStride : undefined;
			var normalized = accessorDef.normalized === true;
			var array, bufferAttribute;

			// The buffer is not interleaved if the stride is the item size in bytes.
			if ( byteStride && byteStride !== itemBytes ) {

				// Each "slice" of the buffer, as defined by 'count' elements of 'byteStride' bytes, gets its own InterleavedBuffer
				// This makes sure that IBA.count reflects accessor.count properly
				var ibSlice = Math.floor( byteOffset / byteStride );
				var ibCacheKey = 'InterleavedBuffer:' + accessorDef.bufferView + ':' + accessorDef.componentType + ':' + ibSlice + ':' + accessorDef.count;
				var ib = parser.cache.get( ibCacheKey );

				if ( ! ib ) {

					array = new TypedArray( bufferView, ibSlice * byteStride, accessorDef.count * byteStride / elementBytes );

					// Integer parameters to IB/IBA are in array elements, not bytes.
					ib = new InterleavedBuffer( array, byteStride / elementBytes );

					parser.cache.add( ibCacheKey, ib );

				}

				bufferAttribute = new InterleavedBufferAttribute( ib, itemSize, ( byteOffset % byteStride ) / elementBytes, normalized );

			} else {

				if ( bufferView === null ) {

					array = new TypedArray( accessorDef.count * itemSize );

				} else {

					array = new TypedArray( bufferView, byteOffset, accessorDef.count * itemSize );

				}

				bufferAttribute = new BufferAttribute( array, itemSize, normalized );

			}

			// https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#sparse-accessors
			if ( accessorDef.sparse !== undefined ) {

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

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

				var sparseIndices = new TypedArrayIndices( bufferViews[ 1 ], byteOffsetIndices, accessorDef.sparse.count * itemSizeIndices );
				var sparseValues = new TypedArray( bufferViews[ 2 ], byteOffsetValues, accessorDef.sparse.count * itemSize );

				if ( bufferView !== null ) {

					// Avoid modifying the original ArrayBuffer, if the bufferView wasn't initialized with zeroes.
					bufferAttribute = new BufferAttribute( bufferAttribute.array.slice(), bufferAttribute.itemSize, bufferAttribute.normalized );

				}

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

					var index = sparseIndices[ i ];

					bufferAttribute.setX( index, sparseValues[ i * itemSize ] );
					if ( itemSize >= 2 ) bufferAttribute.setY( index, sparseValues[ i * itemSize + 1 ] );
					if ( itemSize >= 3 ) bufferAttribute.setZ( index, sparseValues[ i * itemSize + 2 ] );
					if ( itemSize >= 4 ) bufferAttribute.setW( index, sparseValues[ i * itemSize + 3 ] );
					if ( itemSize >= 5 ) throw new Error( 'THREE.GLTFLoader: Unsupported itemSize in sparse BufferAttribute.' );

				}

			}

			return bufferAttribute;

		} );

	};

	/**
	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#textures
	 * @param {number} textureIndex
	 * @return {Promise<THREE.Texture>}
	 */
	GLTFParser.prototype.loadTexture = function ( textureIndex ) {

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

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

		var textureDef = json.textures[ textureIndex ];

		var textureExtensions = textureDef.extensions || {};

		var source;

		if ( textureExtensions[ EXTENSIONS.MSFT_TEXTURE_DDS ] ) {

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

		} else {

			source = json.images[ textureDef.source ];

		}

		var 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 = options.manager.getHandler( sourceURI );

			if ( ! loader ) {

				loader = textureExtensions[ EXTENSIONS.MSFT_TEXTURE_DDS ]
					? parser.extensions[ EXTENSIONS.MSFT_TEXTURE_DDS ].ddsLoader
					: 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 ) texture.name = textureDef.name;

			// Ignore unknown mime types, like DDS files.
			if ( source.mimeType in MIME_TYPE_FORMATS ) {

				texture.format = MIME_TYPE_FORMATS[ source.mimeType ];

			}

			var samplers = json.samplers || {};
			var sampler = samplers[ textureDef.sampler ] || {};

			texture.magFilter = WEBGL_FILTERS[ sampler.magFilter ] || LinearFilter;
			texture.minFilter = WEBGL_FILTERS[ sampler.minFilter ] || LinearMipmapLinearFilter;
			texture.wrapS = WEBGL_WRAPPINGS[ sampler.wrapS ] || RepeatWrapping;
			texture.wrapT = WEBGL_WRAPPINGS[ sampler.wrapT ] || RepeatWrapping;

			return texture;

		} );

	};

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

		var parser = this;

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

			if ( ! texture.isCompressedTexture ) {

				switch ( mapName ) {

					case 'aoMap':
					case 'emissiveMap':
					case 'metalnessMap':
					case 'normalMap':
					case 'roughnessMap':
						texture.format = RGBFormat;
						break;

				}

			}

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

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

			}

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

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

				if ( transform ) {

					texture = parser.extensions[ EXTENSIONS.KHR_TEXTURE_TRANSFORM ].extendTexture( texture, transform );

				}

			}

			materialParams[ mapName ] = texture;

		} );

	};

	/**
	 * Assigns final material to a Mesh, Line, or Points instance. The instance
	 * already has a material (generated from the glTF material options alone)
	 * but reuse of the same glTF material may require multiple threejs materials
	 * to accomodate different primitive types, defines, etc. New materials will
	 * be created if necessary, and reused from a cache.
	 * @param  {Object3D} mesh Mesh, Line, or Points instance.
	 */
	GLTFParser.prototype.assignFinalMaterial = function ( mesh ) {

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

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

		if ( mesh.isPoints ) {

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

			var pointsMaterial = this.cache.get( cacheKey );

			if ( ! pointsMaterial ) {

				pointsMaterial = new PointsMaterial();
				Material.prototype.copy.call( pointsMaterial, material );
				pointsMaterial.color.copy( material.color );
				pointsMaterial.map = material.map;
				pointsMaterial.sizeAttenuation = false; // glTF spec says points should be 1px

				this.cache.add( cacheKey, pointsMaterial );

			}

			material = pointsMaterial;

		} else if ( mesh.isLine ) {

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

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

			if ( ! lineMaterial ) {

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

				this.cache.add( cacheKey, lineMaterial );

			}

			material = lineMaterial;

		}

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

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

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

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

			if ( ! cachedMaterial ) {

				cachedMaterial = material.clone();

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

				this.cache.add( cacheKey, cachedMaterial );

			}

			material = cachedMaterial;

		}

		// workarounds for mesh and geometry

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

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

		}

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

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

		}

		if ( material.clearcoatNormalScale && ! useVertexTangents ) {

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

		}

		mesh.material = material;

	};

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

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

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

		var pending = [];

		if ( materialExtensions[ EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS ] ) {

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

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

			var kmuExtension = extensions[ EXTENSIONS.KHR_MATERIALS_UNLIT ];
			materialType = kmuExtension.getMaterialType();
			pending.push( kmuExtension.extendParams( materialParams, materialDef, parser ) );

		} else {

			// Specification:
			// https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#metallic-roughness-material

			materialType = MeshStandardMaterial;

			var metallicRoughness = materialDef.pbrMetallicRoughness || {};

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

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

				var array = metallicRoughness.baseColorFactor;

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

			}

			if ( metallicRoughness.baseColorTexture !== undefined ) {

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

			}

			materialParams.metalness = metallicRoughness.metallicFactor !== undefined ? metallicRoughness.metallicFactor : 1.0;
			materialParams.roughness = metallicRoughness.roughnessFactor !== undefined ? metallicRoughness.roughnessFactor : 1.0;

			if ( metallicRoughness.metallicRoughnessTexture !== undefined ) {

				pending.push( parser.assignTexture( materialParams, 'metalnessMap', metallicRoughness.metallicRoughnessTexture ) );
				pending.push( parser.assignTexture( materialParams, 'roughnessMap', metallicRoughness.metallicRoughnessTexture ) );

			}

		}

		if ( materialDef.doubleSided === true ) {

			materialParams.side = DoubleSide;

		}

		var alphaMode = materialDef.alphaMode || ALPHA_MODES.OPAQUE;

		if ( alphaMode === ALPHA_MODES.BLEND ) {

			materialParams.transparent = true;

			// See: https://github.com/mrdoob/three.js/issues/17706
			materialParams.depthWrite = false;

		} else {

			materialParams.transparent = false;

			if ( alphaMode === ALPHA_MODES.MASK ) {

				materialParams.alphaTest = materialDef.alphaCutoff !== undefined ? materialDef.alphaCutoff : 0.5;

			}

		}

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

			pending.push( parser.assignTexture( materialParams, 'normalMap', materialDef.normalTexture ) );

			materialParams.normalScale = new Vector2( 1, 1 );

			if ( materialDef.normalTexture.scale !== undefined ) {

				materialParams.normalScale.set( materialDef.normalTexture.scale, materialDef.normalTexture.scale );

			}

		}

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

			pending.push( parser.assignTexture( materialParams, 'aoMap', materialDef.occlusionTexture ) );

			if ( materialDef.occlusionTexture.strength !== undefined ) {

				materialParams.aoMapIntensity = materialDef.occlusionTexture.strength;

			}

		}

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

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

		}

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

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

		}

		if ( materialExtensions[ EXTENSIONS.KHR_MATERIALS_CLEARCOAT ] ) {

			var clearcoatExtension = extensions[ EXTENSIONS.KHR_MATERIALS_CLEARCOAT ];
			materialType = clearcoatExtension.getMaterialType();
			pending.push( clearcoatExtension.extendParams( materialParams, { extensions: materialExtensions }, parser ) );

		}

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

			var material;

			if ( materialType === GLTFMeshStandardSGMaterial ) {

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

			} else {

				material = new materialType( materialParams );

			}

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

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

			assignExtrasToUserData( material, materialDef );

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

			return material;

		} );

	};

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

		var attributes = primitiveDef.attributes;

		var box = new Box3();

		if ( attributes.POSITION !== undefined ) {

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

			var min = accessor.min;
			var max = accessor.max;

			// glTF requires 'min' and 'max', but VRM (which extends glTF) currently ignores that requirement.

			if ( min !== undefined && max !== undefined ) {

				box.set(
					new Vector3( min[ 0 ], min[ 1 ], min[ 2 ] ),
					new Vector3( max[ 0 ], max[ 1 ], max[ 2 ] ) );

			} else {

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

				return;

			}

		} else {

			return;

		}

		var targets = primitiveDef.targets;

		if ( targets !== undefined ) {

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

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

				var target = targets[ i ];

				if ( target.POSITION !== undefined ) {

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

					// glTF requires 'min' and 'max', but VRM (which extends glTF) currently ignores that requirement.

					if ( min !== undefined && max !== undefined ) {

						// we need to get max of absolute components because target weight is [-1,1]
						vector.setX( Math.max( Math.abs( min[ 0 ] ), Math.abs( max[ 0 ] ) ) );
						vector.setY( Math.max( Math.abs( min[ 1 ] ), Math.abs( max[ 1 ] ) ) );
						vector.setZ( Math.max( Math.abs( min[ 2 ] ), Math.abs( max[ 2 ] ) ) );

						// Note: this assumes that the sum of all weights is at most 1. This isn't quite correct - it's more conservative
						// to assume that each target can have a max weight of 1. However, for some use cases - notably, when morph targets
						// are used to implement key-frame animations and as such only two are active at a time - this results in very large
						// boxes. So for now we make a box that's sometimes a touch too small but is hopefully mostly of reasonable size.
						maxDisplacement.max( vector );

					} else {

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

					}

				}

			}

			// As per comment above this box isn't conservative, but has a reasonable size for a very large number of morph targets.
			box.expandByVector( maxDisplacement );

		}

		geometry.boundingBox = box;

		var sphere = new Sphere();

		box.getCenter( sphere.center );
		sphere.radius = box.min.distanceTo( box.max ) / 2;

		geometry.boundingSphere = sphere;

	}

	/**
	 * @param {BufferGeometry} geometry
	 * @param {GLTF.Primitive} primitiveDef
	 * @param {GLTFParser} parser
	 * @return {Promise<BufferGeometry>}
	 */
	function addPrimitiveAttributes( geometry, primitiveDef, parser ) {

		var attributes = primitiveDef.attributes;

		var pending = [];

		function assignAttributeAccessor( accessorIndex, attributeName ) {

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

					geometry.setAttribute( attributeName, accessor );

				} );

		}

		for ( var gltfAttributeName in attributes ) {

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

			// Skip attributes already provided by e.g. Draco extension.
			if ( threeAttributeName in geometry.attributes ) continue;

			pending.push( assignAttributeAccessor( attributes[ gltfAttributeName ], threeAttributeName ) );

		}

		if ( primitiveDef.indices !== undefined && ! geometry.index ) {

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

				geometry.setIndex( accessor );

			} );

			pending.push( accessor );

		}

		assignExtrasToUserData( geometry, primitiveDef );

		computeBounds( geometry, primitiveDef, parser );

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

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

		} );

	}

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

		var index = geometry.getIndex();

		// generate index if not present

		if ( index === null ) {

			var indices = [];

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

			if ( position !== undefined ) {

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

					indices.push( i );

				}

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

			} else {

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

			}

		}

		//

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

		if ( drawMode === TriangleFanDrawMode ) {

			// gl.TRIANGLE_FAN

			for ( var i = 1; i <= numberOfTriangles; i ++ ) {

				newIndices.push( index.getX( 0 ) );
				newIndices.push( index.getX( i ) );
				newIndices.push( index.getX( i + 1 ) );

			}

		} else {

			// gl.TRIANGLE_STRIP

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

				if ( i % 2 === 0 ) {

					newIndices.push( index.getX( i ) );
					newIndices.push( index.getX( i + 1 ) );
					newIndices.push( index.getX( i + 2 ) );


				} else {

					newIndices.push( index.getX( i + 2 ) );
					newIndices.push( index.getX( i + 1 ) );
					newIndices.push( index.getX( i ) );

				}

			}

		}

		if ( ( newIndices.length / 3 ) !== numberOfTriangles ) {

			console.error( 'THREE.GLTFLoader.toTrianglesDrawMode(): Unable to generate correct amount of triangles.' );

		}

		// build final geometry

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

		return newGeometry;

	}

	/**
	 * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#geometry
	 *
	 * Creates BufferGeometries from primitives.
	 *
	 * @param {Array<GLTF.Primitive>} primitives
	 * @return {Promise<Array<BufferGeometry>>}
	 */
	GLTFParser.prototype.loadGeometries = function ( primitives ) {

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

		function createDracoPrimitive( primitive ) {

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

					return addPrimitiveAttributes( geometry, primitive, parser );

				} );

		}

		var pending = [];

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

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

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

			if ( cached ) {

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

			} else {

				var geometryPromise;

				if ( primitive.extensions && primitive.extensions[ EXTENSIONS.KHR_DRACO_MESH_COMPRESSION ] ) {

					// Use DRACO geometry if available
					geometryPromise = createDracoPrimitive( primitive );

				} else {

					// Otherwise create a new geometry
					geometryPromise = addPrimitiveAttributes( new BufferGeometry(), primitive, parser );

				}

				// Cache this geometry
				cache[ cacheKey ] = { primitive: primitive, promise: geometryPromise };

				pending.push( geometryPromise );

			}

		}

		return Promise.all( pending );

	};

	/**
	 * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#meshes
	 * @param {number} meshIndex
	 * @return {Promise<Group|Mesh|SkinnedMesh>}
	 */
	GLTFParser.prototype.loadMesh = function ( meshIndex ) {

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

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

		var pending = [];

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

			var material = primitives[ i ].material === undefined
				? createDefaultMaterial( this.cache )
				: this.getDependency( 'material', primitives[ i ].material );

			pending.push( material );

		}

		pending.push( parser.loadGeometries( primitives ) );

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

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

			var meshes = [];

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

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

				// 1. create Mesh

				var mesh;

				var material = materials[ i ];

				if ( primitive.mode === WEBGL_CONSTANTS.TRIANGLES ||
					primitive.mode === WEBGL_CONSTANTS.TRIANGLE_STRIP ||
					primitive.mode === WEBGL_CONSTANTS.TRIANGLE_FAN ||
					primitive.mode === undefined ) {

					// .isSkinnedMesh isn't in glTF spec. See .markDefs()
					mesh = meshDef.isSkinnedMesh === true
						? new SkinnedMesh( geometry, material )
						: new Mesh( geometry, material );

					if ( mesh.isSkinnedMesh === true && ! mesh.geometry.attributes.skinWeight.normalized ) {

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

					}

					if ( primitive.mode === WEBGL_CONSTANTS.TRIANGLE_STRIP ) {

						mesh.geometry = toTrianglesDrawMode( mesh.geometry, TriangleStripDrawMode );

					} else if ( primitive.mode === WEBGL_CONSTANTS.TRIANGLE_FAN ) {

						mesh.geometry = toTrianglesDrawMode( mesh.geometry, TriangleFanDrawMode );

					}

				} else if ( primitive.mode === WEBGL_CONSTANTS.LINES ) {

					mesh = new LineSegments( geometry, material );

				} else if ( primitive.mode === WEBGL_CONSTANTS.LINE_STRIP ) {

					mesh = new Line( geometry, material );

				} else if ( primitive.mode === WEBGL_CONSTANTS.LINE_LOOP ) {

					mesh = new LineLoop( geometry, material );

				} else if ( primitive.mode === WEBGL_CONSTANTS.POINTS ) {

					mesh = new Points( geometry, material );

				} else {

					throw new Error( 'THREE.GLTFLoader: Primitive mode unsupported: ' + primitive.mode );

				}

				if ( Object.keys( mesh.geometry.morphAttributes ).length > 0 ) {

					updateMorphTargets( mesh, meshDef );

				}

				mesh.name = meshDef.name || ( 'mesh_' + meshIndex );

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

				assignExtrasToUserData( mesh, meshDef );

				parser.assignFinalMaterial( mesh );

				meshes.push( mesh );

			}

			if ( meshes.length === 1 ) {

				return meshes[ 0 ];

			}

			var group = new Group();

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

				group.add( meshes[ i ] );

			}

			return group;

		} );

	};

	/**
	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#cameras
	 * @param {number} cameraIndex
	 * @return {Promise<THREE.Camera>}
	 */
	GLTFParser.prototype.loadCamera = function ( cameraIndex ) {

		var camera;
		var cameraDef = this.json.cameras[ cameraIndex ];
		var params = cameraDef[ cameraDef.type ];

		if ( ! params ) {

			console.warn( 'THREE.GLTFLoader: Missing camera parameters.' );
			return;

		}

		if ( cameraDef.type === 'perspective' ) {

			camera = new PerspectiveCamera( MathUtils.radToDeg( params.yfov ), params.aspectRatio || 1, params.znear || 1, params.zfar || 2e6 );

		} else if ( cameraDef.type === 'orthographic' ) {

			camera = new OrthographicCamera( - params.xmag, params.xmag, params.ymag, - params.ymag, params.znear, params.zfar );

		}

		if ( cameraDef.name ) camera.name = cameraDef.name;

		assignExtrasToUserData( camera, cameraDef );

		return Promise.resolve( camera );

	};

	/**
	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#skins
	 * @param {number} skinIndex
	 * @return {Promise<Object>}
	 */
	GLTFParser.prototype.loadSkin = function ( skinIndex ) {

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

		var skinEntry = { joints: skinDef.joints };

		if ( skinDef.inverseBindMatrices === undefined ) {

			return Promise.resolve( skinEntry );

		}

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

			skinEntry.inverseBindMatrices = accessor;

			return skinEntry;

		} );

	};

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

		var json = this.json;

		var animationDef = json.animations[ animationIndex ];

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

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

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

			pendingNodes.push( this.getDependency( 'node', name ) );
			pendingInputAccessors.push( this.getDependency( 'accessor', input ) );
			pendingOutputAccessors.push( this.getDependency( 'accessor', output ) );
			pendingSamplers.push( sampler );
			pendingTargets.push( target );

		}

		return Promise.all( [

			Promise.all( pendingNodes ),
			Promise.all( pendingInputAccessors ),
			Promise.all( pendingOutputAccessors ),
			Promise.all( pendingSamplers ),
			Promise.all( pendingTargets )

		] ).then( function ( dependencies ) {

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

			var tracks = [];

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

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

				if ( node === undefined ) continue;

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

				var TypedKeyframeTrack;

				switch ( PATH_PROPERTIES[ target.path ] ) {

					case PATH_PROPERTIES.weights:

						TypedKeyframeTrack = NumberKeyframeTrack;
						break;

					case PATH_PROPERTIES.rotation:

						TypedKeyframeTrack = QuaternionKeyframeTrack;
						break;

					case PATH_PROPERTIES.position:
					case PATH_PROPERTIES.scale:
					default:

						TypedKeyframeTrack = VectorKeyframeTrack;
						break;

				}

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

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

				var targetNames = [];

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

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

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

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

						}

					} );

				} else {

					targetNames.push( targetName );

				}

				var outputArray = outputAccessor.array;

				if ( outputAccessor.normalized ) {

					var scale;

					if ( outputArray.constructor === Int8Array ) {

						scale = 1 / 127;

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

						scale = 1 / 255;

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

						scale = 1 / 32767;

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

						scale = 1 / 65535;

					} else {

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

					}

					var scaled = new Float32Array( outputArray.length );

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

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

					}

					outputArray = scaled;

				}

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

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

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

						track.createInterpolant = function InterpolantFactoryMethodGLTFCubicSpline( result ) {

							// A CUBICSPLINE keyframe in glTF has three output values for each input value,
							// representing inTangent, splineVertex, and outTangent. As a result, track.getValueSize()
							// must be divided by three to get the interpolant's sampleSize argument.

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

						};

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

					}

					tracks.push( track );

				}

			}

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

			return new AnimationClip( name, undefined, tracks );

		} );

	};

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

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

		var meshReferences = json.meshReferences;
		var meshUses = json.meshUses;

		var nodeDef = json.nodes[ nodeIndex ];

		return ( function () {

			var pending = [];

			if ( nodeDef.mesh !== undefined ) {

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

					var node;

					if ( meshReferences[ nodeDef.mesh ] > 1 ) {

						var instanceNum = meshUses[ nodeDef.mesh ] ++;

						node = mesh.clone();
						node.name += '_instance_' + instanceNum;

					} else {

						node = mesh;

					}

					// if weights are provided on the node, override weights on the mesh.
					if ( nodeDef.weights !== undefined ) {

						node.traverse( function ( o ) {

							if ( ! o.isMesh ) return;

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

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

							}

						} );

					}

					return node;

				} ) );

			}

			if ( nodeDef.camera !== undefined ) {

				pending.push( parser.getDependency( 'camera', nodeDef.camera ) );

			}

			if ( nodeDef.extensions
				&& nodeDef.extensions[ EXTENSIONS.KHR_LIGHTS_PUNCTUAL ]
				&& nodeDef.extensions[ EXTENSIONS.KHR_LIGHTS_PUNCTUAL ].light !== undefined ) {

				pending.push( parser.getDependency( 'light', nodeDef.extensions[ EXTENSIONS.KHR_LIGHTS_PUNCTUAL ].light ) );

			}

			return Promise.all( pending );

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

			var node;

			// .isBone isn't in glTF spec. See .markDefs
			if ( nodeDef.isBone === true ) {

				node = new Bone();

			} else if ( objects.length > 1 ) {

				node = new Group();

			} else if ( objects.length === 1 ) {

				node = objects[ 0 ];

			} else {

				node = new Object3D();

			}

			if ( node !== objects[ 0 ] ) {

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

					node.add( objects[ i ] );

				}

			}

			if ( nodeDef.name ) {

				node.userData.name = nodeDef.name;
				node.name = PropertyBinding.sanitizeNodeName( nodeDef.name );

			}

			assignExtrasToUserData( node, nodeDef );

			if ( nodeDef.extensions ) addUnknownExtensionsToUserData( extensions, node, nodeDef );

			if ( nodeDef.matrix !== undefined ) {

				var matrix = new Matrix4();
				matrix.fromArray( nodeDef.matrix );
				node.applyMatrix4( matrix );

			} else {

				if ( nodeDef.translation !== undefined ) {

					node.position.fromArray( nodeDef.translation );

				}

				if ( nodeDef.rotation !== undefined ) {

					node.quaternion.fromArray( nodeDef.rotation );

				}

				if ( nodeDef.scale !== undefined ) {

					node.scale.fromArray( nodeDef.scale );

				}

			}

			return node;

		} );

	};

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

		// scene node hierachy builder

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

			var nodeDef = json.nodes[ nodeId ];

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

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

				// build skeleton here as well

				var skinEntry;

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

					skinEntry = skin;

					var pendingJoints = [];

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

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

					}

					return Promise.all( pendingJoints );

				} ).then( function ( jointNodes ) {

					node.traverse( function ( mesh ) {

						if ( ! mesh.isMesh ) return;

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

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

							var jointNode = jointNodes[ j ];

							if ( jointNode ) {

								bones.push( jointNode );

								var mat = new Matrix4();

								if ( skinEntry.inverseBindMatrices !== undefined ) {

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

								}

								boneInverses.push( mat );

							} else {

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

							}

						}

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

					} );

					return node;

				} );

			} ).then( function ( node ) {

				// build node hierachy

				parentObject.add( node );

				var pending = [];

				if ( nodeDef.children ) {

					var children = nodeDef.children;

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

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

					}

				}

				return Promise.all( pending );

			} );

		}

		return function loadScene( sceneIndex ) {

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

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

			assignExtrasToUserData( scene, sceneDef );

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

			var nodeIds = sceneDef.nodes || [];

			var pending = [];

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

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

			}

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

				return scene;

			} );

		};

	}();

	return GLTFLoader;

} )()
Example #4
Source File: BufferGeometryUtils.js    From canvas with Apache License 2.0 4 votes vote down vote up
BufferGeometryUtils = {

	computeTangents: function ( geometry ) {

		var index = geometry.index;
		var attributes = geometry.attributes;

		// based on http://www.terathon.com/code/tangent.html
		// (per vertex tangents)

		if ( index === null ||
			 attributes.position === undefined ||
			 attributes.normal === undefined ||
			 attributes.uv === undefined ) {

			console.error( 'THREE.BufferGeometryUtils: .computeTangents() failed. Missing required attributes (index, position, normal or uv)' );
			return;

		}

		var indices = index.array;
		var positions = attributes.position.array;
		var normals = attributes.normal.array;
		var uvs = attributes.uv.array;

		var nVertices = positions.length / 3;

		if ( attributes.tangent === undefined ) {

			geometry.setAttribute( 'tangent', new BufferAttribute( new Float32Array( 4 * nVertices ), 4 ) );

		}

		var tangents = attributes.tangent.array;

		var tan1 = [], tan2 = [];

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

			tan1[ i ] = new Vector3();
			tan2[ i ] = new Vector3();

		}

		var vA = new Vector3(),
			vB = new Vector3(),
			vC = new Vector3(),

			uvA = new Vector2(),
			uvB = new Vector2(),
			uvC = new Vector2(),

			sdir = new Vector3(),
			tdir = new Vector3();

		function handleTriangle( a, b, c ) {

			vA.fromArray( positions, a * 3 );
			vB.fromArray( positions, b * 3 );
			vC.fromArray( positions, c * 3 );

			uvA.fromArray( uvs, a * 2 );
			uvB.fromArray( uvs, b * 2 );
			uvC.fromArray( uvs, c * 2 );

			vB.sub( vA );
			vC.sub( vA );

			uvB.sub( uvA );
			uvC.sub( uvA );

			var r = 1.0 / ( uvB.x * uvC.y - uvC.x * uvB.y );

			// silently ignore degenerate uv triangles having coincident or colinear vertices

			if ( ! isFinite( r ) ) return;

			sdir.copy( vB ).multiplyScalar( uvC.y ).addScaledVector( vC, - uvB.y ).multiplyScalar( r );
			tdir.copy( vC ).multiplyScalar( uvB.x ).addScaledVector( vB, - uvC.x ).multiplyScalar( r );

			tan1[ a ].add( sdir );
			tan1[ b ].add( sdir );
			tan1[ c ].add( sdir );

			tan2[ a ].add( tdir );
			tan2[ b ].add( tdir );
			tan2[ c ].add( tdir );

		}

		var groups = geometry.groups;

		if ( groups.length === 0 ) {

			groups = [ {
				start: 0,
				count: indices.length
			} ];

		}

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

			var group = groups[ i ];

			var start = group.start;
			var count = group.count;

			for ( var j = start, jl = start + count; j < jl; j += 3 ) {

				handleTriangle(
					indices[ j + 0 ],
					indices[ j + 1 ],
					indices[ j + 2 ]
				);

			}

		}

		var tmp = new Vector3(), tmp2 = new Vector3();
		var n = new Vector3(), n2 = new Vector3();
		var w, t, test;

		function handleVertex( v ) {

			n.fromArray( normals, v * 3 );
			n2.copy( n );

			t = tan1[ v ];

			// Gram-Schmidt orthogonalize

			tmp.copy( t );
			tmp.sub( n.multiplyScalar( n.dot( t ) ) ).normalize();

			// Calculate handedness

			tmp2.crossVectors( n2, t );
			test = tmp2.dot( tan2[ v ] );
			w = ( test < 0.0 ) ? - 1.0 : 1.0;

			tangents[ v * 4 ] = tmp.x;
			tangents[ v * 4 + 1 ] = tmp.y;
			tangents[ v * 4 + 2 ] = tmp.z;
			tangents[ v * 4 + 3 ] = w;

		}

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

			var group = groups[ i ];

			var start = group.start;
			var count = group.count;

			for ( var j = start, jl = start + count; j < jl; j += 3 ) {

				handleVertex( indices[ j + 0 ] );
				handleVertex( indices[ j + 1 ] );
				handleVertex( indices[ j + 2 ] );

			}

		}

	},

	/**
	 * @param  {Array<BufferGeometry>} geometries
	 * @param  {Boolean} useGroups
	 * @return {BufferGeometry}
	 */
	mergeBufferGeometries: function ( geometries, useGroups ) {

		var isIndexed = geometries[ 0 ].index !== null;

		var attributesUsed = new Set( Object.keys( geometries[ 0 ].attributes ) );
		var morphAttributesUsed = new Set( Object.keys( geometries[ 0 ].morphAttributes ) );

		var attributes = {};
		var morphAttributes = {};

		var morphTargetsRelative = geometries[ 0 ].morphTargetsRelative;

		var mergedGeometry = new BufferGeometry();

		var offset = 0;

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

			var geometry = geometries[ i ];
			var attributesCount = 0;

			// ensure that all geometries are indexed, or none

			if ( isIndexed !== ( geometry.index !== null ) ) {

				console.error( 'THREE.BufferGeometryUtils: .mergeBufferGeometries() failed with geometry at index ' + i + '. All geometries must have compatible attributes; make sure index attribute exists among all geometries, or in none of them.' );
				return null;

			}

			// gather attributes, exit early if they're different

			for ( var name in geometry.attributes ) {

				if ( ! attributesUsed.has( name ) ) {

					console.error( 'THREE.BufferGeometryUtils: .mergeBufferGeometries() failed with geometry at index ' + i + '. All geometries must have compatible attributes; make sure "' + name + '" attribute exists among all geometries, or in none of them.' );
					return null;

				}

				if ( attributes[ name ] === undefined ) attributes[ name ] = [];

				attributes[ name ].push( geometry.attributes[ name ] );

				attributesCount ++;

			}

			// ensure geometries have the same number of attributes

			if ( attributesCount !== attributesUsed.size ) {

				console.error( 'THREE.BufferGeometryUtils: .mergeBufferGeometries() failed with geometry at index ' + i + '. Make sure all geometries have the same number of attributes.' );
				return null;

			}

			// gather morph attributes, exit early if they're different

			if ( morphTargetsRelative !== geometry.morphTargetsRelative ) {

				console.error( 'THREE.BufferGeometryUtils: .mergeBufferGeometries() failed with geometry at index ' + i + '. .morphTargetsRelative must be consistent throughout all geometries.' );
				return null;

			}

			for ( var name in geometry.morphAttributes ) {

				if ( ! morphAttributesUsed.has( name ) ) {

					console.error( 'THREE.BufferGeometryUtils: .mergeBufferGeometries() failed with geometry at index ' + i + '.  .morphAttributes must be consistent throughout all geometries.' );
					return null;

				}

				if ( morphAttributes[ name ] === undefined ) morphAttributes[ name ] = [];

				morphAttributes[ name ].push( geometry.morphAttributes[ name ] );

			}

			// gather .userData

			mergedGeometry.userData.mergedUserData = mergedGeometry.userData.mergedUserData || [];
			mergedGeometry.userData.mergedUserData.push( geometry.userData );

			if ( useGroups ) {

				var count;

				if ( isIndexed ) {

					count = geometry.index.count;

				} else if ( geometry.attributes.position !== undefined ) {

					count = geometry.attributes.position.count;

				} else {

					console.error( 'THREE.BufferGeometryUtils: .mergeBufferGeometries() failed with geometry at index ' + i + '. The geometry must have either an index or a position attribute' );
					return null;

				}

				mergedGeometry.addGroup( offset, count, i );

				offset += count;

			}

		}

		// merge indices

		if ( isIndexed ) {

			var indexOffset = 0;
			var mergedIndex = [];

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

				var index = geometries[ i ].index;

				for ( var j = 0; j < index.count; ++ j ) {

					mergedIndex.push( index.getX( j ) + indexOffset );

				}

				indexOffset += geometries[ i ].attributes.position.count;

			}

			mergedGeometry.setIndex( mergedIndex );

		}

		// merge attributes

		for ( var name in attributes ) {

			var mergedAttribute = this.mergeBufferAttributes( attributes[ name ] );

			if ( ! mergedAttribute ) {

				console.error( 'THREE.BufferGeometryUtils: .mergeBufferGeometries() failed while trying to merge the ' + name + ' attribute.' );
				return null;

			}

			mergedGeometry.setAttribute( name, mergedAttribute );

		}

		// merge morph attributes

		for ( var name in morphAttributes ) {

			var numMorphTargets = morphAttributes[ name ][ 0 ].length;

			if ( numMorphTargets === 0 ) break;

			mergedGeometry.morphAttributes = mergedGeometry.morphAttributes || {};
			mergedGeometry.morphAttributes[ name ] = [];

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

				var morphAttributesToMerge = [];

				for ( var j = 0; j < morphAttributes[ name ].length; ++ j ) {

					morphAttributesToMerge.push( morphAttributes[ name ][ j ][ i ] );

				}

				var mergedMorphAttribute = this.mergeBufferAttributes( morphAttributesToMerge );

				if ( ! mergedMorphAttribute ) {

					console.error( 'THREE.BufferGeometryUtils: .mergeBufferGeometries() failed while trying to merge the ' + name + ' morphAttribute.' );
					return null;

				}

				mergedGeometry.morphAttributes[ name ].push( mergedMorphAttribute );

			}

		}

		return mergedGeometry;

	},

	/**
	 * @param {Array<BufferAttribute>} attributes
	 * @return {BufferAttribute}
	 */
	mergeBufferAttributes: function ( attributes ) {

		var TypedArray;
		var itemSize;
		var normalized;
		var arrayLength = 0;

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

			var attribute = attributes[ i ];

			if ( attribute.isInterleavedBufferAttribute ) {

				console.error( 'THREE.BufferGeometryUtils: .mergeBufferAttributes() failed. InterleavedBufferAttributes are not supported.' );
				return null;

			}

			if ( TypedArray === undefined ) TypedArray = attribute.array.constructor;
			if ( TypedArray !== attribute.array.constructor ) {

				console.error( 'THREE.BufferGeometryUtils: .mergeBufferAttributes() failed. BufferAttribute.array must be of consistent array types across matching attributes.' );
				return null;

			}

			if ( itemSize === undefined ) itemSize = attribute.itemSize;
			if ( itemSize !== attribute.itemSize ) {

				console.error( 'THREE.BufferGeometryUtils: .mergeBufferAttributes() failed. BufferAttribute.itemSize must be consistent across matching attributes.' );
				return null;

			}

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

				console.error( 'THREE.BufferGeometryUtils: .mergeBufferAttributes() failed. BufferAttribute.normalized must be consistent across matching attributes.' );
				return null;

			}

			arrayLength += attribute.array.length;

		}

		var array = new TypedArray( arrayLength );
		var offset = 0;

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

			array.set( attributes[ i ].array, offset );

			offset += attributes[ i ].array.length;

		}

		return new BufferAttribute( array, itemSize, normalized );

	},

	/**
	 * @param {Array<BufferAttribute>} attributes
	 * @return {Array<InterleavedBufferAttribute>}
	 */
	interleaveAttributes: function ( attributes ) {

		// Interleaves the provided attributes into an InterleavedBuffer and returns
		// a set of InterleavedBufferAttributes for each attribute
		var TypedArray;
		var arrayLength = 0;
		var stride = 0;

		// calculate the the length and type of the interleavedBuffer
		for ( var i = 0, l = attributes.length; i < l; ++ i ) {

			var attribute = attributes[ i ];

			if ( TypedArray === undefined ) TypedArray = attribute.array.constructor;
			if ( TypedArray !== attribute.array.constructor ) {

				console.error( 'AttributeBuffers of different types cannot be interleaved' );
				return null;

			}

			arrayLength += attribute.array.length;
			stride += attribute.itemSize;

		}

		// Create the set of buffer attributes
		var interleavedBuffer = new InterleavedBuffer( new TypedArray( arrayLength ), stride );
		var offset = 0;
		var res = [];
		var getters = [ 'getX', 'getY', 'getZ', 'getW' ];
		var setters = [ 'setX', 'setY', 'setZ', 'setW' ];

		for ( var j = 0, l = attributes.length; j < l; j ++ ) {

			var attribute = attributes[ j ];
			var itemSize = attribute.itemSize;
			var count = attribute.count;
			var iba = new InterleavedBufferAttribute( interleavedBuffer, itemSize, offset, attribute.normalized );
			res.push( iba );

			offset += itemSize;

			// Move the data for each attribute into the new interleavedBuffer
			// at the appropriate offset
			for ( var c = 0; c < count; c ++ ) {

				for ( var k = 0; k < itemSize; k ++ ) {

					iba[ setters[ k ] ]( c, attribute[ getters[ k ] ]( c ) );

				}

			}

		}

		return res;

	},

	/**
	 * @param {Array<BufferGeometry>} geometry
	 * @return {number}
	 */
	estimateBytesUsed: function ( geometry ) {

		// Return the estimated memory used by this geometry in bytes
		// Calculate using itemSize, count, and BYTES_PER_ELEMENT to account
		// for InterleavedBufferAttributes.
		var mem = 0;
		for ( var name in geometry.attributes ) {

			var attr = geometry.getAttribute( name );
			mem += attr.count * attr.itemSize * attr.array.BYTES_PER_ELEMENT;

		}

		var indices = geometry.getIndex();
		mem += indices ? indices.count * indices.itemSize * indices.array.BYTES_PER_ELEMENT : 0;
		return mem;

	},

	/**
	 * @param {BufferGeometry} geometry
	 * @param {number} tolerance
	 * @return {BufferGeometry>}
	 */
	mergeVertices: function ( geometry, tolerance = 1e-4 ) {

		tolerance = Math.max( tolerance, Number.EPSILON );

		// Generate an index buffer if the geometry doesn't have one, or optimize it
		// if it's already available.
		var hashToIndex = {};
		var indices = geometry.getIndex();
		var positions = geometry.getAttribute( 'position' );
		var vertexCount = indices ? indices.count : positions.count;

		// next value for triangle indices
		var nextIndex = 0;

		// attributes and new attribute arrays
		var attributeNames = Object.keys( geometry.attributes );
		var attrArrays = {};
		var morphAttrsArrays = {};
		var newIndices = [];
		var getters = [ 'getX', 'getY', 'getZ', 'getW' ];

		// initialize the arrays
		for ( var i = 0, l = attributeNames.length; i < l; i ++ ) {

			var name = attributeNames[ i ];

			attrArrays[ name ] = [];

			var morphAttr = geometry.morphAttributes[ name ];
			if ( morphAttr ) {

				morphAttrsArrays[ name ] = new Array( morphAttr.length ).fill().map( () => [] );

			}

		}

		// convert the error tolerance to an amount of decimal places to truncate to
		var decimalShift = Math.log10( 1 / tolerance );
		var shiftMultiplier = Math.pow( 10, decimalShift );
		for ( var i = 0; i < vertexCount; i ++ ) {

			var index = indices ? indices.getX( i ) : i;

			// Generate a hash for the vertex attributes at the current index 'i'
			var hash = '';
			for ( var j = 0, l = attributeNames.length; j < l; j ++ ) {

				var name = attributeNames[ j ];
				var attribute = geometry.getAttribute( name );
				var itemSize = attribute.itemSize;

				for ( var k = 0; k < itemSize; k ++ ) {

					// double tilde truncates the decimal value
					hash += `${ ~ ~ ( attribute[ getters[ k ] ]( index ) * shiftMultiplier ) },`;

				}

			}

			// Add another reference to the vertex if it's already
			// used by another index
			if ( hash in hashToIndex ) {

				newIndices.push( hashToIndex[ hash ] );

			} else {

				// copy data to the new index in the attribute arrays
				for ( var j = 0, l = attributeNames.length; j < l; j ++ ) {

					var name = attributeNames[ j ];
					var attribute = geometry.getAttribute( name );
					var morphAttr = geometry.morphAttributes[ name ];
					var itemSize = attribute.itemSize;
					var newarray = attrArrays[ name ];
					var newMorphArrays = morphAttrsArrays[ name ];

					for ( var k = 0; k < itemSize; k ++ ) {

						var getterFunc = getters[ k ];
						newarray.push( attribute[ getterFunc ]( index ) );

						if ( morphAttr ) {

							for ( var m = 0, ml = morphAttr.length; m < ml; m ++ ) {

								newMorphArrays[ m ].push( morphAttr[ m ][ getterFunc ]( index ) );

							}

						}

					}

				}

				hashToIndex[ hash ] = nextIndex;
				newIndices.push( nextIndex );
				nextIndex ++;

			}

		}

		// Generate typed arrays from new attribute arrays and update
		// the attributeBuffers
		const result = geometry.clone();
		for ( var i = 0, l = attributeNames.length; i < l; i ++ ) {

			var name = attributeNames[ i ];
			var oldAttribute = geometry.getAttribute( name );

			var buffer = new oldAttribute.array.constructor( attrArrays[ name ] );
			var attribute = new BufferAttribute( buffer, oldAttribute.itemSize, oldAttribute.normalized );

			result.setAttribute( name, attribute );

			// Update the attribute arrays
			if ( name in morphAttrsArrays ) {

				for ( var j = 0; j < morphAttrsArrays[ name ].length; j ++ ) {

					var oldMorphAttribute = geometry.morphAttributes[ name ][ j ];

					var buffer = new oldMorphAttribute.array.constructor( morphAttrsArrays[ name ][ j ] );
					var morphAttribute = new BufferAttribute( buffer, oldMorphAttribute.itemSize, oldMorphAttribute.normalized );
					result.morphAttributes[ name ][ j ] = morphAttribute;

				}

			}

		}

		// indices

		result.setIndex( newIndices );

		return result;

	},

	/**
	 * @param {BufferGeometry} geometry
	 * @param {number} drawMode
	 * @return {BufferGeometry>}
	 */
	toTrianglesDrawMode: function ( geometry, drawMode ) {

		if ( drawMode === TrianglesDrawMode ) {

			console.warn( 'THREE.BufferGeometryUtils.toTrianglesDrawMode(): Geometry already defined as triangles.' );
			return geometry;

		}

		if ( drawMode === TriangleFanDrawMode || drawMode === TriangleStripDrawMode ) {

			var index = geometry.getIndex();

			// generate index if not present

			if ( index === null ) {

				var indices = [];

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

				if ( position !== undefined ) {

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

						indices.push( i );

					}

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

				} else {

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

				}

			}

			//

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

			if ( drawMode === TriangleFanDrawMode ) {

				// gl.TRIANGLE_FAN

				for ( var i = 1; i <= numberOfTriangles; i ++ ) {

					newIndices.push( index.getX( 0 ) );
					newIndices.push( index.getX( i ) );
					newIndices.push( index.getX( i + 1 ) );

				}

			} else {

				// gl.TRIANGLE_STRIP

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

					if ( i % 2 === 0 ) {

						newIndices.push( index.getX( i ) );
						newIndices.push( index.getX( i + 1 ) );
						newIndices.push( index.getX( i + 2 ) );


					} else {

						newIndices.push( index.getX( i + 2 ) );
						newIndices.push( index.getX( i + 1 ) );
						newIndices.push( index.getX( i ) );

					}

				}

			}

			if ( ( newIndices.length / 3 ) !== numberOfTriangles ) {

				console.error( 'THREE.BufferGeometryUtils.toTrianglesDrawMode(): Unable to generate correct amount of triangles.' );

			}

			// build final geometry

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

			return newGeometry;

		} else {

			console.error( 'THREE.BufferGeometryUtils.toTrianglesDrawMode(): Unknown draw mode:', drawMode );
			return geometry;

		}

	}

}
Example #5
Source File: GLTFLoader.js    From FirstPersonCameraControl with MIT License 4 votes vote down vote up
GLTFLoader = ( function () {

	function GLTFLoader( manager ) {

		Loader.call( this, manager );

		this.dracoLoader = null;
		this.ddsLoader = null;

	}

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

		constructor: GLTFLoader,

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

			var scope = this;

			var resourcePath;

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

				resourcePath = this.resourcePath;

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

				resourcePath = this.path;

			} else {

				resourcePath = LoaderUtils.extractUrlBase( url );

			}

			// Tells the LoadingManager to track an extra item, which resolves after
			// the model is fully loaded. This means the count of items loaded will
			// be incorrect, but ensures manager.onLoad() does not fire early.
			scope.manager.itemStart( url );

			var _onError = function ( e ) {

				if ( onError ) {

					onError( e );

				} else {

					console.error( e );

				}

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

			};

			var loader = new FileLoader( scope.manager );

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

			if ( scope.crossOrigin === 'use-credentials' ) {

				loader.setWithCredentials( true );

			}

			loader.load( url, function ( data ) {

				try {

					scope.parse( data, resourcePath, function ( gltf ) {

						onLoad( gltf );

						scope.manager.itemEnd( url );

					}, _onError );

				} catch ( e ) {

					_onError( e );

				}

			}, onProgress, _onError );

		},

		setDRACOLoader: function ( dracoLoader ) {

			this.dracoLoader = dracoLoader;
			return this;

		},

		setDDSLoader: function ( ddsLoader ) {

			this.ddsLoader = ddsLoader;
			return this;

		},

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

			var content;
			var extensions = {};

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

				content = data;

			} else {

				var magic = LoaderUtils.decodeText( new Uint8Array( data, 0, 4 ) );

				if ( magic === BINARY_EXTENSION_HEADER_MAGIC ) {

					try {

						extensions[ EXTENSIONS.KHR_BINARY_GLTF ] = new GLTFBinaryExtension( data );

					} catch ( error ) {

						if ( onError ) onError( error );
						return;

					}

					content = extensions[ EXTENSIONS.KHR_BINARY_GLTF ].content;

				} else {

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

				}

			}

			var json = JSON.parse( content );

			if ( json.asset === undefined || json.asset.version[ 0 ] < 2 ) {

				if ( onError ) onError( new Error( 'THREE.GLTFLoader: Unsupported asset. glTF versions >=2.0 are supported.' ) );
				return;

			}

			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_CLEARCOAT:
							extensions[ extensionName ] = new GLTFMaterialsClearcoatExtension();
							break;

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

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

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

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

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

						case EXTENSIONS.KHR_MESH_QUANTIZATION:
							extensions[ extensionName ] = new GLTFMeshQuantizationExtension();
							break;

						default:

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

								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( onLoad, onError );

		}

	} );

	/* GLTFREGISTRY */

	function GLTFRegistry() {

		var objects = {};

		return	{

			get: function ( key ) {

				return objects[ key ];

			},

			add: function ( key, object ) {

				objects[ key ] = object;

			},

			remove: function ( key ) {

				delete objects[ key ];

			},

			removeAll: function () {

				objects = {};

			}

		};

	}

	/*********************************/
	/********** EXTENSIONS ***********/
	/*********************************/

	var EXTENSIONS = {
		KHR_BINARY_GLTF: 'KHR_binary_glTF',
		KHR_DRACO_MESH_COMPRESSION: 'KHR_draco_mesh_compression',
		KHR_LIGHTS_PUNCTUAL: 'KHR_lights_punctual',
		KHR_MATERIALS_CLEARCOAT: 'KHR_materials_clearcoat',
		KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS: 'KHR_materials_pbrSpecularGlossiness',
		KHR_MATERIALS_UNLIT: 'KHR_materials_unlit',
		KHR_TEXTURE_TRANSFORM: 'KHR_texture_transform',
		KHR_MESH_QUANTIZATION: 'KHR_mesh_quantization',
		MSFT_TEXTURE_DDS: 'MSFT_texture_dds'
	};

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

		if ( ! ddsLoader ) {

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

		}

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

	}

	/**
	 * Punctual Lights Extension
	 *
	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_lights_punctual
	 */
	function GLTFLightsExtension( 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 Color( 0xffffff );
		if ( lightDef.color !== undefined ) color.fromArray( lightDef.color );

		var range = lightDef.range !== undefined ? lightDef.range : 0;

		switch ( lightDef.type ) {

			case 'directional':
				lightNode = new DirectionalLight( color );
				lightNode.target.position.set( 0, 0, - 1 );
				lightNode.add( lightNode.target );
				break;

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

			case 'spot':
				lightNode = new SpotLight( color );
				lightNode.distance = range;
				// Handle spotlight properties.
				lightDef.spot = lightDef.spot || {};
				lightDef.spot.innerConeAngle = lightDef.spot.innerConeAngle !== undefined ? lightDef.spot.innerConeAngle : 0;
				lightDef.spot.outerConeAngle = lightDef.spot.outerConeAngle !== undefined ? lightDef.spot.outerConeAngle : Math.PI / 4.0;
				lightNode.angle = lightDef.spot.outerConeAngle;
				lightNode.penumbra = 1.0 - lightDef.spot.innerConeAngle / lightDef.spot.outerConeAngle;
				lightNode.target.position.set( 0, 0, - 1 );
				lightNode.add( lightNode.target );
				break;

			default:
				throw new Error( 'THREE.GLTFLoader: Unexpected light type, "' + lightDef.type + '".' );

		}

		// Some lights (e.g. spot) default to a position other than the origin. Reset the position
		// here, because node-level parsing will only override position if explicitly specified.
		lightNode.position.set( 0, 0, 0 );

		lightNode.decay = 2;

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

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

		return Promise.resolve( lightNode );

	};

	/**
	 * Unlit Materials Extension
	 *
	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_materials_unlit
	 */
	function GLTFMaterialsUnlitExtension() {

		this.name = EXTENSIONS.KHR_MATERIALS_UNLIT;

	}

	GLTFMaterialsUnlitExtension.prototype.getMaterialType = function () {

		return MeshBasicMaterial;

	};

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

		var pending = [];

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

		var metallicRoughness = materialDef.pbrMetallicRoughness;

		if ( metallicRoughness ) {

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

				var array = metallicRoughness.baseColorFactor;

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

			}

			if ( metallicRoughness.baseColorTexture !== undefined ) {

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

			}

		}

		return Promise.all( pending );

	};

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

		this.name = EXTENSIONS.KHR_MATERIALS_CLEARCOAT;

	}

	GLTFMaterialsClearcoatExtension.prototype.getMaterialType = function () {

		return MeshPhysicalMaterial;

	};

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

		var pending = [];

		var extension = materialDef.extensions[ this.name ];

		if ( extension.clearcoatFactor !== undefined ) {

			materialParams.clearcoat = extension.clearcoatFactor;

		}

		if ( extension.clearcoatTexture !== undefined ) {

			pending.push( parser.assignTexture( materialParams, 'clearcoatMap', extension.clearcoatTexture ) );

		}

		if ( extension.clearcoatRoughnessFactor !== undefined ) {

			materialParams.clearcoatRoughness = extension.clearcoatRoughnessFactor;

		}

		if ( extension.clearcoatRoughnessTexture !== undefined ) {

			pending.push( parser.assignTexture( materialParams, 'clearcoatRoughnessMap', extension.clearcoatRoughnessTexture ) );

		}

		if ( extension.clearcoatNormalTexture !== undefined ) {

			pending.push( parser.assignTexture( materialParams, 'clearcoatNormalMap', extension.clearcoatNormalTexture ) );

			if ( extension.clearcoatNormalTexture.scale !== undefined ) {

				var scale = extension.clearcoatNormalTexture.scale;

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

			}

		}

		return Promise.all( pending );

	};

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

	function GLTFBinaryExtension( data ) {

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

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

		this.header = {
			magic: LoaderUtils.decodeText( new Uint8Array( data.slice( 0, 4 ) ) ),
			version: headerView.getUint32( 4, true ),
			length: headerView.getUint32( 8, true )
		};

		if ( this.header.magic !== BINARY_EXTENSION_HEADER_MAGIC ) {

			throw new Error( 'THREE.GLTFLoader: Unsupported glTF-Binary header.' );

		} else if ( this.header.version < 2.0 ) {

			throw new Error( 'THREE.GLTFLoader: Legacy binary file detected.' );

		}

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

		while ( chunkIndex < chunkView.byteLength ) {

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

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

			if ( chunkType === BINARY_EXTENSION_CHUNK_TYPES.JSON ) {

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

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

				var byteOffset = BINARY_EXTENSION_HEADER_LENGTH + chunkIndex;
				this.body = data.slice( byteOffset, byteOffset + chunkLength );

			}

			// Clients must ignore chunks with unknown types.

			chunkIndex += chunkLength;

		}

		if ( this.content === null ) {

			throw new Error( 'THREE.GLTFLoader: JSON content not found.' );

		}

	}

	/**
	 * DRACO Mesh Compression Extension
	 *
	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_draco_mesh_compression
	 */
	function GLTFDracoMeshCompressionExtension( json, dracoLoader ) {

		if ( ! dracoLoader ) {

			throw new Error( 'THREE.GLTFLoader: No DRACOLoader instance provided.' );

		}

		this.name = EXTENSIONS.KHR_DRACO_MESH_COMPRESSION;
		this.json = json;
		this.dracoLoader = dracoLoader;
		this.dracoLoader.preload();

	}

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

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

		for ( var attributeName in gltfAttributeMap ) {

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

			threeAttributeMap[ threeAttributeName ] = gltfAttributeMap[ attributeName ];

		}

		for ( attributeName in primitive.attributes ) {

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

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

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

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

			}

		}

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

			return new Promise( function ( resolve ) {

				dracoLoader.decodeDracoFile( bufferView, function ( geometry ) {

					for ( var attributeName in geometry.attributes ) {

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

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

					}

					resolve( geometry );

				}, threeAttributeMap, attributeTypeMap );

			} );

		} );

	};

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

		this.name = EXTENSIONS.KHR_TEXTURE_TRANSFORM;

	}

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

		texture = texture.clone();

		if ( transform.offset !== undefined ) {

			texture.offset.fromArray( transform.offset );

		}

		if ( transform.rotation !== undefined ) {

			texture.rotation = transform.rotation;

		}

		if ( transform.scale !== undefined ) {

			texture.repeat.fromArray( transform.scale );

		}

		if ( transform.texCoord !== undefined ) {

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

		}

		texture.needsUpdate = true;

		return texture;

	};

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

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

	function GLTFMeshStandardSGMaterial( params ) {

		MeshStandardMaterial.call( this );

		this.isGLTFSpecularGlossinessMaterial = true;

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

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

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

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

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

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

		this._extraUniforms = uniforms;

		// please see #14031 or #13198 for an alternate approach
		this.onBeforeCompile = function ( shader ) {

			for ( var uniformName in uniforms ) {

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

			}

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

		};

		/*eslint-disable*/
		Object.defineProperties(
			this,
			{
				specular: {
					get: function () { return uniforms.specular.value; },
					set: function ( v ) { uniforms.specular.value = v; }
				},
				specularMap: {
					get: function () { return uniforms.specularMap.value; },
					set: function ( v ) { uniforms.specularMap.value = v; }
				},
				glossiness: {
					get: function () { return uniforms.glossiness.value; },
					set: function ( v ) { uniforms.glossiness.value = v; }
				},
				glossinessMap: {
					get: function () { return uniforms.glossinessMap.value; },
					set: function ( v ) {

						uniforms.glossinessMap.value = v;
						//how about something like this - @pailhead
						if ( v ) {

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

						} else {

							delete this.defines.USE_ROUGHNESSMAP;
							delete this.defines.USE_GLOSSINESSMAP;

						}

					}
				}
			}
		);

		/*eslint-enable*/
		delete this.metalness;
		delete this.roughness;
		delete this.metalnessMap;
		delete this.roughnessMap;

		this.setValues( params );

	}

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

	GLTFMeshStandardSGMaterial.prototype.copy = function ( source ) {

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

	};

	function GLTFMaterialsPbrSpecularGlossinessExtension() {

		return {

			name: EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS,

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

			getMaterialType: function () {

				return GLTFMeshStandardSGMaterial;

			},

			extendParams: function ( materialParams, materialDef, parser ) {

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

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

				var pending = [];

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

					var array = pbrSpecularGlossiness.diffuseFactor;

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

				}

				if ( pbrSpecularGlossiness.diffuseTexture !== undefined ) {

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

				}

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

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

					materialParams.specular.fromArray( pbrSpecularGlossiness.specularFactor );

				}

				if ( pbrSpecularGlossiness.specularGlossinessTexture !== undefined ) {

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

				}

				return Promise.all( pending );

			},

			createMaterial: function ( materialParams ) {

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

				material.color = materialParams.color;

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

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

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

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

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

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

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

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

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

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

				material.alphaMap = null;

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

				material.refractionRatio = 0.98;

				return material;

			},

		};

	}

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

		this.name = EXTENSIONS.KHR_MESH_QUANTIZATION;

	}

	/*********************************/
	/********** INTERPOLATION ********/
	/*********************************/

	// Spline Interpolation
	// Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#appendix-c-spline-interpolation
	function GLTFCubicSplineInterpolant( parameterPositions, sampleValues, sampleSize, resultBuffer ) {

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

	}

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

	GLTFCubicSplineInterpolant.prototype.copySampleValue_ = function ( index ) {

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

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

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

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

		}

		return result;

	};

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

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

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

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

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

		var td = t1 - t0;

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

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

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

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

			var p0 = values[ offset0 + i + stride ]; // splineVertex_k
			var m0 = values[ offset0 + i + stride2 ] * td; // outTangent_k * (t_k+1 - t_k)
			var p1 = values[ offset1 + i + stride ]; // splineVertex_k+1
			var m1 = values[ offset1 + i ] * td; // inTangent_k+1 * (t_k+1 - t_k)

			result[ i ] = s0 * p0 + s1 * m0 + s2 * p1 + s3 * m1;

		}

		return result;

	};

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

	/* CONSTANTS */

	var WEBGL_CONSTANTS = {
		FLOAT: 5126,
		//FLOAT_MAT2: 35674,
		FLOAT_MAT3: 35675,
		FLOAT_MAT4: 35676,
		FLOAT_VEC2: 35664,
		FLOAT_VEC3: 35665,
		FLOAT_VEC4: 35666,
		LINEAR: 9729,
		REPEAT: 10497,
		SAMPLER_2D: 35678,
		POINTS: 0,
		LINES: 1,
		LINE_LOOP: 2,
		LINE_STRIP: 3,
		TRIANGLES: 4,
		TRIANGLE_STRIP: 5,
		TRIANGLE_FAN: 6,
		UNSIGNED_BYTE: 5121,
		UNSIGNED_SHORT: 5123
	};

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

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

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

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

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

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

	var INTERPOLATION = {
		CUBICSPLINE: undefined, // We use a custom interpolant (GLTFCubicSplineInterpolation) for CUBICSPLINE tracks. Each
		                        // keyframe track will be initialized with a default interpolation type, then modified.
		LINEAR: InterpolateLinear,
		STEP: InterpolateDiscrete
	};

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

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

	/* UTILITY FUNCTIONS */

	function resolveURL( url, path ) {

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

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

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

		}

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

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

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

		// Relative URL
		return path + url;

	}

	/**
	 * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#default-material
	 */
	function createDefaultMaterial( cache ) {

		if ( cache[ 'DefaultMaterial' ] === undefined ) {

			cache[ 'DefaultMaterial' ] = new MeshStandardMaterial( {
				color: 0xFFFFFF,
				emissive: 0x000000,
				metalness: 1,
				roughness: 1,
				transparent: false,
				depthTest: true,
				side: FrontSide
			} );

		}

		return cache[ 'DefaultMaterial' ];

	}

	function addUnknownExtensionsToUserData( knownExtensions, object, objectDef ) {

		// Add unknown glTF extensions to an object's userData.

		for ( var name in objectDef.extensions ) {

			if ( knownExtensions[ name ] === undefined ) {

				object.userData.gltfExtensions = object.userData.gltfExtensions || {};
				object.userData.gltfExtensions[ name ] = objectDef.extensions[ name ];

			}

		}

	}

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

		if ( gltfDef.extras !== undefined ) {

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

				Object.assign( object.userData, gltfDef.extras );

			} else {

				console.warn( 'THREE.GLTFLoader: Ignoring primitive type .extras, ' + gltfDef.extras );

			}

		}

	}

	/**
	 * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#morph-targets
	 *
	 * @param {BufferGeometry} geometry
	 * @param {Array<GLTF.Target>} targets
	 * @param {GLTFParser} parser
	 * @return {Promise<BufferGeometry>}
	 */
	function addMorphTargets( geometry, targets, parser ) {

		var hasMorphPosition = false;
		var hasMorphNormal = false;

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

			var target = targets[ i ];

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

			if ( hasMorphPosition && hasMorphNormal ) break;

		}

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

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

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

			var target = targets[ i ];

			if ( hasMorphPosition ) {

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

				pendingPositionAccessors.push( pendingAccessor );

			}

			if ( hasMorphNormal ) {

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

				pendingNormalAccessors.push( pendingAccessor );

			}

		}

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

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

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

			return geometry;

		} );

	}

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

		mesh.updateMorphTargets();

		if ( meshDef.weights !== undefined ) {

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

				mesh.morphTargetInfluences[ i ] = meshDef.weights[ i ];

			}

		}

		// .extras has user-defined data, so check that .extras.targetNames is an array.
		if ( meshDef.extras && Array.isArray( meshDef.extras.targetNames ) ) {

			var targetNames = meshDef.extras.targetNames;

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

				mesh.morphTargetDictionary = {};

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

					mesh.morphTargetDictionary[ targetNames[ i ] ] = i;

				}

			} else {

				console.warn( 'THREE.GLTFLoader: Invalid extras.targetNames length. Ignoring names.' );

			}

		}

	}

	function createPrimitiveKey( primitiveDef ) {

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

		if ( dracoExtension ) {

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

		} else {

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

		}

		return geometryKey;

	}

	function createAttributesKey( attributes ) {

		var attributesKey = '';

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

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

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

		}

		return attributesKey;

	}

	/* GLTF PARSER */

	function GLTFParser( json, 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 TextureLoader( this.options.manager );
		this.textureLoader.setCrossOrigin( this.options.crossOrigin );

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

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

			this.fileLoader.setWithCredentials( true );

		}

	}

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

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

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

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

		Promise.all( [

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

		] ).then( function ( dependencies ) {

			var result = {
				scene: dependencies[ 0 ][ json.scene || 0 ],
				scenes: dependencies[ 0 ],
				animations: dependencies[ 1 ],
				cameras: dependencies[ 2 ],
				asset: json.asset,
				parser: parser,
				userData: {}
			};

			addUnknownExtensionsToUserData( extensions, result, json );

			assignExtrasToUserData( result, json );

			onLoad( result );

		} ).catch( onError );

	};

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

		var nodeDefs = this.json.nodes || [];
		var skinDefs = this.json.skins || [];
		var meshDefs = this.json.meshes || [];

		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 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<Object3D|Material|THREE.Texture|AnimationClip|ArrayBuffer|Object>}
	 */
	GLTFParser.prototype.getDependency = function ( type, index ) {

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

		if ( ! dependency ) {

			switch ( type ) {

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

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

				case 'mesh':
					dependency = this.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;

	};

	/**
	 * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#buffers-and-buffer-views
	 * @param {number} bufferIndex
	 * @return {Promise<ArrayBuffer>}
	 */
	GLTFParser.prototype.loadBuffer = function ( bufferIndex ) {

		var bufferDef = this.json.buffers[ bufferIndex ];
		var loader = this.fileLoader;

		if ( bufferDef.type && bufferDef.type !== 'arraybuffer' ) {

			throw new Error( 'THREE.GLTFLoader: ' + bufferDef.type + ' buffer type is not supported.' );

		}

		// If present, GLB container is required to be the first buffer.
		if ( bufferDef.uri === undefined && bufferIndex === 0 ) {

			return Promise.resolve( this.extensions[ EXTENSIONS.KHR_BINARY_GLTF ].body );

		}

		var options = this.options;

		return new Promise( function ( resolve, reject ) {

			loader.load( resolveURL( bufferDef.uri, options.path ), resolve, undefined, function () {

				reject( new Error( 'THREE.GLTFLoader: Failed to load buffer "' + bufferDef.uri + '".' ) );

			} );

		} );

	};

	/**
	 * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#buffers-and-buffer-views
	 * @param {number} bufferViewIndex
	 * @return {Promise<ArrayBuffer>}
	 */
	GLTFParser.prototype.loadBufferView = function ( bufferViewIndex ) {

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

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

			var byteLength = bufferViewDef.byteLength || 0;
			var byteOffset = bufferViewDef.byteOffset || 0;
			return buffer.slice( byteOffset, byteOffset + byteLength );

		} );

	};

	/**
	 * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#accessors
	 * @param {number} accessorIndex
	 * @return {Promise<BufferAttribute|InterleavedBufferAttribute>}
	 */
	GLTFParser.prototype.loadAccessor = function ( accessorIndex ) {

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

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

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

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

		}

		var pendingBufferViews = [];

		if ( accessorDef.bufferView !== undefined ) {

			pendingBufferViews.push( this.getDependency( 'bufferView', accessorDef.bufferView ) );

		} else {

			pendingBufferViews.push( null );

		}

		if ( accessorDef.sparse !== undefined ) {

			pendingBufferViews.push( this.getDependency( 'bufferView', accessorDef.sparse.indices.bufferView ) );
			pendingBufferViews.push( this.getDependency( 'bufferView', accessorDef.sparse.values.bufferView ) );

		}

		return Promise.all( pendingBufferViews ).then( function ( bufferViews ) {

			var bufferView = bufferViews[ 0 ];

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

			// For VEC3: itemSize is 3, elementBytes is 4, itemBytes is 12.
			var elementBytes = TypedArray.BYTES_PER_ELEMENT;
			var itemBytes = elementBytes * itemSize;
			var byteOffset = accessorDef.byteOffset || 0;
			var byteStride = accessorDef.bufferView !== undefined ? json.bufferViews[ accessorDef.bufferView ].byteStride : undefined;
			var normalized = accessorDef.normalized === true;
			var array, bufferAttribute;

			// The buffer is not interleaved if the stride is the item size in bytes.
			if ( byteStride && byteStride !== itemBytes ) {

				// Each "slice" of the buffer, as defined by 'count' elements of 'byteStride' bytes, gets its own InterleavedBuffer
				// This makes sure that IBA.count reflects accessor.count properly
				var ibSlice = Math.floor( byteOffset / byteStride );
				var ibCacheKey = 'InterleavedBuffer:' + accessorDef.bufferView + ':' + accessorDef.componentType + ':' + ibSlice + ':' + accessorDef.count;
				var ib = parser.cache.get( ibCacheKey );

				if ( ! ib ) {

					array = new TypedArray( bufferView, ibSlice * byteStride, accessorDef.count * byteStride / elementBytes );

					// Integer parameters to IB/IBA are in array elements, not bytes.
					ib = new InterleavedBuffer( array, byteStride / elementBytes );

					parser.cache.add( ibCacheKey, ib );

				}

				bufferAttribute = new InterleavedBufferAttribute( ib, itemSize, ( byteOffset % byteStride ) / elementBytes, normalized );

			} else {

				if ( bufferView === null ) {

					array = new TypedArray( accessorDef.count * itemSize );

				} else {

					array = new TypedArray( bufferView, byteOffset, accessorDef.count * itemSize );

				}

				bufferAttribute = new BufferAttribute( array, itemSize, normalized );

			}

			// https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#sparse-accessors
			if ( accessorDef.sparse !== undefined ) {

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

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

				var sparseIndices = new TypedArrayIndices( bufferViews[ 1 ], byteOffsetIndices, accessorDef.sparse.count * itemSizeIndices );
				var sparseValues = new TypedArray( bufferViews[ 2 ], byteOffsetValues, accessorDef.sparse.count * itemSize );

				if ( bufferView !== null ) {

					// Avoid modifying the original ArrayBuffer, if the bufferView wasn't initialized with zeroes.
					bufferAttribute = new BufferAttribute( bufferAttribute.array.slice(), bufferAttribute.itemSize, bufferAttribute.normalized );

				}

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

					var index = sparseIndices[ i ];

					bufferAttribute.setX( index, sparseValues[ i * itemSize ] );
					if ( itemSize >= 2 ) bufferAttribute.setY( index, sparseValues[ i * itemSize + 1 ] );
					if ( itemSize >= 3 ) bufferAttribute.setZ( index, sparseValues[ i * itemSize + 2 ] );
					if ( itemSize >= 4 ) bufferAttribute.setW( index, sparseValues[ i * itemSize + 3 ] );
					if ( itemSize >= 5 ) throw new Error( 'THREE.GLTFLoader: Unsupported itemSize in sparse BufferAttribute.' );

				}

			}

			return bufferAttribute;

		} );

	};

	/**
	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#textures
	 * @param {number} textureIndex
	 * @return {Promise<THREE.Texture>}
	 */
	GLTFParser.prototype.loadTexture = function ( textureIndex ) {

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

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

		var textureDef = json.textures[ textureIndex ];

		var textureExtensions = textureDef.extensions || {};

		var source;

		if ( textureExtensions[ EXTENSIONS.MSFT_TEXTURE_DDS ] ) {

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

		} else {

			source = json.images[ textureDef.source ];

		}

		var 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 = options.manager.getHandler( sourceURI );

			if ( ! loader ) {

				loader = textureExtensions[ EXTENSIONS.MSFT_TEXTURE_DDS ]
					? parser.extensions[ EXTENSIONS.MSFT_TEXTURE_DDS ].ddsLoader
					: 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 ) texture.name = textureDef.name;

			// Ignore unknown mime types, like DDS files.
			if ( source.mimeType in MIME_TYPE_FORMATS ) {

				texture.format = MIME_TYPE_FORMATS[ source.mimeType ];

			}

			var samplers = json.samplers || {};
			var sampler = samplers[ textureDef.sampler ] || {};

			texture.magFilter = WEBGL_FILTERS[ sampler.magFilter ] || LinearFilter;
			texture.minFilter = WEBGL_FILTERS[ sampler.minFilter ] || LinearMipmapLinearFilter;
			texture.wrapS = WEBGL_WRAPPINGS[ sampler.wrapS ] || RepeatWrapping;
			texture.wrapT = WEBGL_WRAPPINGS[ sampler.wrapT ] || RepeatWrapping;

			return texture;

		} );

	};

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

		var parser = this;

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

			if ( ! texture.isCompressedTexture ) {

				switch ( mapName ) {

					case 'aoMap':
					case 'emissiveMap':
					case 'metalnessMap':
					case 'normalMap':
					case 'roughnessMap':
						texture.format = RGBFormat;
						break;

				}

			}

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

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

			}

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

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

				if ( transform ) {

					texture = parser.extensions[ EXTENSIONS.KHR_TEXTURE_TRANSFORM ].extendTexture( texture, transform );

				}

			}

			materialParams[ mapName ] = texture;

		} );

	};

	/**
	 * Assigns final material to a Mesh, Line, or Points instance. The instance
	 * already has a material (generated from the glTF material options alone)
	 * but reuse of the same glTF material may require multiple threejs materials
	 * to accomodate different primitive types, defines, etc. New materials will
	 * be created if necessary, and reused from a cache.
	 * @param  {Object3D} mesh Mesh, Line, or Points instance.
	 */
	GLTFParser.prototype.assignFinalMaterial = function ( mesh ) {

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

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

		if ( mesh.isPoints ) {

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

			var pointsMaterial = this.cache.get( cacheKey );

			if ( ! pointsMaterial ) {

				pointsMaterial = new PointsMaterial();
				Material.prototype.copy.call( pointsMaterial, material );
				pointsMaterial.color.copy( material.color );
				pointsMaterial.map = material.map;
				pointsMaterial.sizeAttenuation = false; // glTF spec says points should be 1px

				this.cache.add( cacheKey, pointsMaterial );

			}

			material = pointsMaterial;

		} else if ( mesh.isLine ) {

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

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

			if ( ! lineMaterial ) {

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

				this.cache.add( cacheKey, lineMaterial );

			}

			material = lineMaterial;

		}

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

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

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

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

			if ( ! cachedMaterial ) {

				cachedMaterial = material.clone();

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

				this.cache.add( cacheKey, cachedMaterial );

			}

			material = cachedMaterial;

		}

		// workarounds for mesh and geometry

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

			geometry.setAttribute( 'uv2', new BufferAttribute( geometry.attributes.uv.array, 2 ) );

		}

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

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

		}

		if ( material.clearcoatNormalScale && ! useVertexTangents ) {

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

		}

		mesh.material = material;

	};

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

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

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

		var pending = [];

		if ( materialExtensions[ EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS ] ) {

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

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

			var kmuExtension = extensions[ EXTENSIONS.KHR_MATERIALS_UNLIT ];
			materialType = kmuExtension.getMaterialType();
			pending.push( kmuExtension.extendParams( materialParams, materialDef, parser ) );

		} else {

			// Specification:
			// https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#metallic-roughness-material

			materialType = MeshStandardMaterial;

			var metallicRoughness = materialDef.pbrMetallicRoughness || {};

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

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

				var array = metallicRoughness.baseColorFactor;

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

			}

			if ( metallicRoughness.baseColorTexture !== undefined ) {

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

			}

			materialParams.metalness = metallicRoughness.metallicFactor !== undefined ? metallicRoughness.metallicFactor : 1.0;
			materialParams.roughness = metallicRoughness.roughnessFactor !== undefined ? metallicRoughness.roughnessFactor : 1.0;

			if ( metallicRoughness.metallicRoughnessTexture !== undefined ) {

				pending.push( parser.assignTexture( materialParams, 'metalnessMap', metallicRoughness.metallicRoughnessTexture ) );
				pending.push( parser.assignTexture( materialParams, 'roughnessMap', metallicRoughness.metallicRoughnessTexture ) );

			}

		}

		if ( materialDef.doubleSided === true ) {

			materialParams.side = DoubleSide;

		}

		var alphaMode = materialDef.alphaMode || ALPHA_MODES.OPAQUE;

		if ( alphaMode === ALPHA_MODES.BLEND ) {

			materialParams.transparent = true;

			// See: https://github.com/mrdoob/three.js/issues/17706
			materialParams.depthWrite = false;

		} else {

			materialParams.transparent = false;

			if ( alphaMode === ALPHA_MODES.MASK ) {

				materialParams.alphaTest = materialDef.alphaCutoff !== undefined ? materialDef.alphaCutoff : 0.5;

			}

		}

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

			pending.push( parser.assignTexture( materialParams, 'normalMap', materialDef.normalTexture ) );

			materialParams.normalScale = new Vector2( 1, 1 );

			if ( materialDef.normalTexture.scale !== undefined ) {

				materialParams.normalScale.set( materialDef.normalTexture.scale, materialDef.normalTexture.scale );

			}

		}

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

			pending.push( parser.assignTexture( materialParams, 'aoMap', materialDef.occlusionTexture ) );

			if ( materialDef.occlusionTexture.strength !== undefined ) {

				materialParams.aoMapIntensity = materialDef.occlusionTexture.strength;

			}

		}

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

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

		}

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

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

		}

		if ( materialExtensions[ EXTENSIONS.KHR_MATERIALS_CLEARCOAT ] ) {

			var clearcoatExtension = extensions[ EXTENSIONS.KHR_MATERIALS_CLEARCOAT ];
			materialType = clearcoatExtension.getMaterialType();
			pending.push( clearcoatExtension.extendParams( materialParams, { extensions: materialExtensions }, parser ) );

		}

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

			var material;

			if ( materialType === GLTFMeshStandardSGMaterial ) {

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

			} else {

				material = new materialType( materialParams );

			}

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

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

			assignExtrasToUserData( material, materialDef );

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

			return material;

		} );

	};

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

		var attributes = primitiveDef.attributes;

		var box = new Box3();

		if ( attributes.POSITION !== undefined ) {

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

			var min = accessor.min;
			var max = accessor.max;

			// glTF requires 'min' and 'max', but VRM (which extends glTF) currently ignores that requirement.

			if ( min !== undefined && max !== undefined ) {

				box.set(
					new Vector3( min[ 0 ], min[ 1 ], min[ 2 ] ),
					new Vector3( max[ 0 ], max[ 1 ], max[ 2 ] ) );

			} else {

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

				return;

			}

		} else {

			return;

		}

		var targets = primitiveDef.targets;

		if ( targets !== undefined ) {

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

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

				var target = targets[ i ];

				if ( target.POSITION !== undefined ) {

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

					// glTF requires 'min' and 'max', but VRM (which extends glTF) currently ignores that requirement.

					if ( min !== undefined && max !== undefined ) {

						// we need to get max of absolute components because target weight is [-1,1]
						vector.setX( Math.max( Math.abs( min[ 0 ] ), Math.abs( max[ 0 ] ) ) );
						vector.setY( Math.max( Math.abs( min[ 1 ] ), Math.abs( max[ 1 ] ) ) );
						vector.setZ( Math.max( Math.abs( min[ 2 ] ), Math.abs( max[ 2 ] ) ) );

						// Note: this assumes that the sum of all weights is at most 1. This isn't quite correct - it's more conservative
						// to assume that each target can have a max weight of 1. However, for some use cases - notably, when morph targets
						// are used to implement key-frame animations and as such only two are active at a time - this results in very large
						// boxes. So for now we make a box that's sometimes a touch too small but is hopefully mostly of reasonable size.
						maxDisplacement.max( vector );

					} else {

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

					}

				}

			}

			// As per comment above this box isn't conservative, but has a reasonable size for a very large number of morph targets.
			box.expandByVector( maxDisplacement );

		}

		geometry.boundingBox = box;

		var sphere = new Sphere();

		box.getCenter( sphere.center );
		sphere.radius = box.min.distanceTo( box.max ) / 2;

		geometry.boundingSphere = sphere;

	}

	/**
	 * @param {BufferGeometry} geometry
	 * @param {GLTF.Primitive} primitiveDef
	 * @param {GLTFParser} parser
	 * @return {Promise<BufferGeometry>}
	 */
	function addPrimitiveAttributes( geometry, primitiveDef, parser ) {

		var attributes = primitiveDef.attributes;

		var pending = [];

		function assignAttributeAccessor( accessorIndex, attributeName ) {

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

					geometry.setAttribute( attributeName, accessor );

				} );

		}

		for ( var gltfAttributeName in attributes ) {

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

			// Skip attributes already provided by e.g. Draco extension.
			if ( threeAttributeName in geometry.attributes ) continue;

			pending.push( assignAttributeAccessor( attributes[ gltfAttributeName ], threeAttributeName ) );

		}

		if ( primitiveDef.indices !== undefined && ! geometry.index ) {

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

				geometry.setIndex( accessor );

			} );

			pending.push( accessor );

		}

		assignExtrasToUserData( geometry, primitiveDef );

		computeBounds( geometry, primitiveDef, parser );

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

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

		} );

	}

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

		var index = geometry.getIndex();

		// generate index if not present

		if ( index === null ) {

			var indices = [];

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

			if ( position !== undefined ) {

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

					indices.push( i );

				}

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

			} else {

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

			}

		}

		//

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

		if ( drawMode === TriangleFanDrawMode ) {

			// gl.TRIANGLE_FAN

			for ( var i = 1; i <= numberOfTriangles; i ++ ) {

				newIndices.push( index.getX( 0 ) );
				newIndices.push( index.getX( i ) );
				newIndices.push( index.getX( i + 1 ) );

			}

		} else {

			// gl.TRIANGLE_STRIP

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

				if ( i % 2 === 0 ) {

					newIndices.push( index.getX( i ) );
					newIndices.push( index.getX( i + 1 ) );
					newIndices.push( index.getX( i + 2 ) );


				} else {

					newIndices.push( index.getX( i + 2 ) );
					newIndices.push( index.getX( i + 1 ) );
					newIndices.push( index.getX( i ) );

				}

			}

		}

		if ( ( newIndices.length / 3 ) !== numberOfTriangles ) {

			console.error( 'THREE.GLTFLoader.toTrianglesDrawMode(): Unable to generate correct amount of triangles.' );

		}

		// build final geometry

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

		return newGeometry;

	}

	/**
	 * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#geometry
	 *
	 * Creates BufferGeometries from primitives.
	 *
	 * @param {Array<GLTF.Primitive>} primitives
	 * @return {Promise<Array<BufferGeometry>>}
	 */
	GLTFParser.prototype.loadGeometries = function ( primitives ) {

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

		function createDracoPrimitive( primitive ) {

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

					return addPrimitiveAttributes( geometry, primitive, parser );

				} );

		}

		var pending = [];

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

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

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

			if ( cached ) {

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

			} else {

				var geometryPromise;

				if ( primitive.extensions && primitive.extensions[ EXTENSIONS.KHR_DRACO_MESH_COMPRESSION ] ) {

					// Use DRACO geometry if available
					geometryPromise = createDracoPrimitive( primitive );

				} else {

					// Otherwise create a new geometry
					geometryPromise = addPrimitiveAttributes( new BufferGeometry(), primitive, parser );

				}

				// Cache this geometry
				cache[ cacheKey ] = { primitive: primitive, promise: geometryPromise };

				pending.push( geometryPromise );

			}

		}

		return Promise.all( pending );

	};

	/**
	 * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#meshes
	 * @param {number} meshIndex
	 * @return {Promise<Group|Mesh|SkinnedMesh>}
	 */
	GLTFParser.prototype.loadMesh = function ( meshIndex ) {

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

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

		var pending = [];

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

			var material = primitives[ i ].material === undefined
				? createDefaultMaterial( this.cache )
				: this.getDependency( 'material', primitives[ i ].material );

			pending.push( material );

		}

		pending.push( parser.loadGeometries( primitives ) );

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

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

			var meshes = [];

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

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

				// 1. create Mesh

				var mesh;

				var material = materials[ i ];

				if ( primitive.mode === WEBGL_CONSTANTS.TRIANGLES ||
					primitive.mode === WEBGL_CONSTANTS.TRIANGLE_STRIP ||
					primitive.mode === WEBGL_CONSTANTS.TRIANGLE_FAN ||
					primitive.mode === undefined ) {

					// .isSkinnedMesh isn't in glTF spec. See .markDefs()
					mesh = meshDef.isSkinnedMesh === true
						? new SkinnedMesh( geometry, material )
						: new Mesh( geometry, material );

					if ( mesh.isSkinnedMesh === true && ! mesh.geometry.attributes.skinWeight.normalized ) {

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

					}

					if ( primitive.mode === WEBGL_CONSTANTS.TRIANGLE_STRIP ) {

						mesh.geometry = toTrianglesDrawMode( mesh.geometry, TriangleStripDrawMode );

					} else if ( primitive.mode === WEBGL_CONSTANTS.TRIANGLE_FAN ) {

						mesh.geometry = toTrianglesDrawMode( mesh.geometry, TriangleFanDrawMode );

					}

				} else if ( primitive.mode === WEBGL_CONSTANTS.LINES ) {

					mesh = new LineSegments( geometry, material );

				} else if ( primitive.mode === WEBGL_CONSTANTS.LINE_STRIP ) {

					mesh = new Line( geometry, material );

				} else if ( primitive.mode === WEBGL_CONSTANTS.LINE_LOOP ) {

					mesh = new LineLoop( geometry, material );

				} else if ( primitive.mode === WEBGL_CONSTANTS.POINTS ) {

					mesh = new Points( geometry, material );

				} else {

					throw new Error( 'THREE.GLTFLoader: Primitive mode unsupported: ' + primitive.mode );

				}

				if ( Object.keys( mesh.geometry.morphAttributes ).length > 0 ) {

					updateMorphTargets( mesh, meshDef );

				}

				mesh.name = meshDef.name || ( 'mesh_' + meshIndex );

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

				assignExtrasToUserData( mesh, meshDef );

				parser.assignFinalMaterial( mesh );

				meshes.push( mesh );

			}

			if ( meshes.length === 1 ) {

				return meshes[ 0 ];

			}

			var group = new Group();

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

				group.add( meshes[ i ] );

			}

			return group;

		} );

	};

	/**
	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#cameras
	 * @param {number} cameraIndex
	 * @return {Promise<THREE.Camera>}
	 */
	GLTFParser.prototype.loadCamera = function ( cameraIndex ) {

		var camera;
		var cameraDef = this.json.cameras[ cameraIndex ];
		var params = cameraDef[ cameraDef.type ];

		if ( ! params ) {

			console.warn( 'THREE.GLTFLoader: Missing camera parameters.' );
			return;

		}

		if ( cameraDef.type === 'perspective' ) {

			camera = new PerspectiveCamera( MathUtils.radToDeg( params.yfov ), params.aspectRatio || 1, params.znear || 1, params.zfar || 2e6 );

		} else if ( cameraDef.type === 'orthographic' ) {

			camera = new OrthographicCamera( params.xmag / - 2, params.xmag / 2, params.ymag / 2, params.ymag / - 2, params.znear, params.zfar );

		}

		if ( cameraDef.name ) camera.name = cameraDef.name;

		assignExtrasToUserData( camera, cameraDef );

		return Promise.resolve( camera );

	};

	/**
	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#skins
	 * @param {number} skinIndex
	 * @return {Promise<Object>}
	 */
	GLTFParser.prototype.loadSkin = function ( skinIndex ) {

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

		var skinEntry = { joints: skinDef.joints };

		if ( skinDef.inverseBindMatrices === undefined ) {

			return Promise.resolve( skinEntry );

		}

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

			skinEntry.inverseBindMatrices = accessor;

			return skinEntry;

		} );

	};

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

		var json = this.json;

		var animationDef = json.animations[ animationIndex ];

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

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

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

			pendingNodes.push( this.getDependency( 'node', name ) );
			pendingInputAccessors.push( this.getDependency( 'accessor', input ) );
			pendingOutputAccessors.push( this.getDependency( 'accessor', output ) );
			pendingSamplers.push( sampler );
			pendingTargets.push( target );

		}

		return Promise.all( [

			Promise.all( pendingNodes ),
			Promise.all( pendingInputAccessors ),
			Promise.all( pendingOutputAccessors ),
			Promise.all( pendingSamplers ),
			Promise.all( pendingTargets )

		] ).then( function ( dependencies ) {

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

			var tracks = [];

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

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

				if ( node === undefined ) continue;

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

				var TypedKeyframeTrack;

				switch ( PATH_PROPERTIES[ target.path ] ) {

					case PATH_PROPERTIES.weights:

						TypedKeyframeTrack = NumberKeyframeTrack;
						break;

					case PATH_PROPERTIES.rotation:

						TypedKeyframeTrack = QuaternionKeyframeTrack;
						break;

					case PATH_PROPERTIES.position:
					case PATH_PROPERTIES.scale:
					default:

						TypedKeyframeTrack = VectorKeyframeTrack;
						break;

				}

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

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

				var targetNames = [];

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

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

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

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

						}

					} );

				} else {

					targetNames.push( targetName );

				}

				var outputArray = outputAccessor.array;

				if ( outputAccessor.normalized ) {

					var scale;

					if ( outputArray.constructor === Int8Array ) {

						scale = 1 / 127;

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

						scale = 1 / 255;

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

						scale = 1 / 32767;

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

						scale = 1 / 65535;

					} else {

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

					}

					var scaled = new Float32Array( outputArray.length );

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

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

					}

					outputArray = scaled;

				}

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

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

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

						track.createInterpolant = function InterpolantFactoryMethodGLTFCubicSpline( result ) {

							// A CUBICSPLINE keyframe in glTF has three output values for each input value,
							// representing inTangent, splineVertex, and outTangent. As a result, track.getValueSize()
							// must be divided by three to get the interpolant's sampleSize argument.

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

						};

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

					}

					tracks.push( track );

				}

			}

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

			return new AnimationClip( name, undefined, tracks );

		} );

	};

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

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

		var meshReferences = json.meshReferences;
		var meshUses = json.meshUses;

		var nodeDef = json.nodes[ nodeIndex ];

		return ( function () {

			var pending = [];

			if ( nodeDef.mesh !== undefined ) {

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

					var node;

					if ( meshReferences[ nodeDef.mesh ] > 1 ) {

						var instanceNum = meshUses[ nodeDef.mesh ] ++;

						node = mesh.clone();
						node.name += '_instance_' + instanceNum;

					} else {

						node = mesh;

					}

					// if weights are provided on the node, override weights on the mesh.
					if ( nodeDef.weights !== undefined ) {

						node.traverse( function ( o ) {

							if ( ! o.isMesh ) return;

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

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

							}

						} );

					}

					return node;

				} ) );

			}

			if ( nodeDef.camera !== undefined ) {

				pending.push( parser.getDependency( 'camera', nodeDef.camera ) );

			}

			if ( nodeDef.extensions
				&& nodeDef.extensions[ EXTENSIONS.KHR_LIGHTS_PUNCTUAL ]
				&& nodeDef.extensions[ EXTENSIONS.KHR_LIGHTS_PUNCTUAL ].light !== undefined ) {

				pending.push( parser.getDependency( 'light', nodeDef.extensions[ EXTENSIONS.KHR_LIGHTS_PUNCTUAL ].light ) );

			}

			return Promise.all( pending );

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

			var node;

			// .isBone isn't in glTF spec. See .markDefs
			if ( nodeDef.isBone === true ) {

				node = new Bone();

			} else if ( objects.length > 1 ) {

				node = new Group();

			} else if ( objects.length === 1 ) {

				node = objects[ 0 ];

			} else {

				node = new Object3D();

			}

			if ( node !== objects[ 0 ] ) {

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

					node.add( objects[ i ] );

				}

			}

			if ( nodeDef.name ) {

				node.userData.name = nodeDef.name;
				node.name = PropertyBinding.sanitizeNodeName( nodeDef.name );

			}

			assignExtrasToUserData( node, nodeDef );

			if ( nodeDef.extensions ) addUnknownExtensionsToUserData( extensions, node, nodeDef );

			if ( nodeDef.matrix !== undefined ) {

				var matrix = new Matrix4();
				matrix.fromArray( nodeDef.matrix );
				node.applyMatrix4( matrix );

			} else {

				if ( nodeDef.translation !== undefined ) {

					node.position.fromArray( nodeDef.translation );

				}

				if ( nodeDef.rotation !== undefined ) {

					node.quaternion.fromArray( nodeDef.rotation );

				}

				if ( nodeDef.scale !== undefined ) {

					node.scale.fromArray( nodeDef.scale );

				}

			}

			return node;

		} );

	};

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

		// scene node hierachy builder

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

			var nodeDef = json.nodes[ nodeId ];

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

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

				// build skeleton here as well

				var skinEntry;

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

					skinEntry = skin;

					var pendingJoints = [];

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

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

					}

					return Promise.all( pendingJoints );

				} ).then( function ( jointNodes ) {

					node.traverse( function ( mesh ) {

						if ( ! mesh.isMesh ) return;

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

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

							var jointNode = jointNodes[ j ];

							if ( jointNode ) {

								bones.push( jointNode );

								var mat = new Matrix4();

								if ( skinEntry.inverseBindMatrices !== undefined ) {

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

								}

								boneInverses.push( mat );

							} else {

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

							}

						}

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

					} );

					return node;

				} );

			} ).then( function ( node ) {

				// build node hierachy

				parentObject.add( node );

				var pending = [];

				if ( nodeDef.children ) {

					var children = nodeDef.children;

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

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

					}

				}

				return Promise.all( pending );

			} );

		}

		return function loadScene( sceneIndex ) {

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

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

			assignExtrasToUserData( scene, sceneDef );

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

			var nodeIds = sceneDef.nodes || [];

			var pending = [];

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

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

			}

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

				return scene;

			} );

		};

	}();

	return GLTFLoader;

} )()