const THREE = require('../../three.js');

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

(function () {

	class GLTFLoader extends THREE.Loader {

		constructor(manager) {

			super(manager);
			this.dracoLoader = null;
			this.ktx2Loader = null;
			this.meshoptDecoder = null;
			this.pluginCallbacks = [];
			this.register(function (parser) {

				return new GLTFMaterialsClearcoatExtension(parser);

			});
			this.register(function (parser) {

				return new GLTFTextureBasisUExtension(parser);

			});
			this.register(function (parser) {

				return new GLTFTextureWebPExtension(parser);

			});
			this.register(function (parser) {

				return new GLTFMaterialsTransmissionExtension(parser);

			});
			this.register(function (parser) {

				return new GLTFMaterialsVolumeExtension(parser);

			});
			this.register(function (parser) {

				return new GLTFMaterialsIorExtension(parser);

			});
			this.register(function (parser) {

				return new GLTFMaterialsSpecularExtension(parser);

			});
			this.register(function (parser) {

				return new GLTFLightsExtension(parser);

			});
			this.register(function (parser) {

				return new GLTFMeshoptCompression(parser);

			});

		}

		load(url, onLoad, onProgress, onError) {

			const scope = this;
			let resourcePath;

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

				resourcePath = this.resourcePath;

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

				resourcePath = this.path;

			} else {

				resourcePath = THREE.LoaderUtils.extractUrlBase(url);

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


			this.manager.itemStart(url);

			const _onError = function (e) {

				if (onError) {

					onError(e);

				} else {

					console.error(e);

				}

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

			};

			const loader = new THREE.FileLoader(this.manager);
			loader.setPath(this.path);
			loader.setResponseType('arraybuffer');
			loader.setRequestHeader(this.requestHeader);
			loader.setWithCredentials(this.withCredentials);
			loader.load(url, function (data) {

				try {

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

						onLoad(gltf);
						scope.manager.itemEnd(url);

					}, _onError);

				} catch (e) {

					_onError(e);

				}

			}, onProgress, _onError);

		}

		setDRACOLoader(dracoLoader) {

			this.dracoLoader = dracoLoader;
			return this;

		}

		setDDSLoader() {

			throw new Error('THREE.GLTFLoader: "MSFT_texture_dds" no longer supported. Please update to "KHR_texture_basisu".');

		}

		setKTX2Loader(ktx2Loader) {

			this.ktx2Loader = ktx2Loader;
			return this;

		}

		setMeshoptDecoder(meshoptDecoder) {

			this.meshoptDecoder = meshoptDecoder;
			return this;

		}

		register(callback) {

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

				this.pluginCallbacks.push(callback);

			}

			return this;

		}

		unregister(callback) {

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

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

			}

			return this;

		}

		parse(data, path, onLoad, onError) {

			let content;
			const extensions = {};
			const plugins = {};

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

				content = data;

			} else {

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

				if (magic === BINARY_EXTENSION_HEADER_MAGIC) {

					try {

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

					} catch (error) {

						if (onError) onError(error);
						return;

					}

					content = extensions[EXTENSIONS.KHR_BINARY_GLTF].content;

				} else {

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

				}

			}

			const 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;

			}

			const parser = new GLTFParser(json, {
				path: path || this.resourcePath || '',
				crossOrigin: this.crossOrigin,
				requestHeader: this.requestHeader,
				manager: this.manager,
				ktx2Loader: this.ktx2Loader,
				meshoptDecoder: this.meshoptDecoder
			});
			parser.fileLoader.setRequestHeader(this.requestHeader);

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

				const plugin = this.pluginCallbacks[i](parser);
				plugins[plugin.name] = plugin; // Workaround to avoid determining as unknown extension
				// in addUnknownExtensionsToUserData().
				// Remove this workaround if we move all the existing
				// extension handlers to plugin system

				extensions[plugin.name] = true;

			}

			if (json.extensionsUsed) {

				for (let i = 0; i < json.extensionsUsed.length; ++i) {

					const extensionName = json.extensionsUsed[i];
					const extensionsRequired = json.extensionsRequired || [];

					switch (extensionName) {

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

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

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

						default:
							if (extensionsRequired.indexOf(extensionName) >= 0 && plugins[extensionName] === undefined) {

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

							}

					}

				}

			}

			parser.setExtensions(extensions);
			parser.setPlugins(plugins);
			parser.parse(onLoad, onError);

		}

	}
	/* GLTFREGISTRY */


	function GLTFRegistry() {

		let objects = {};
		return {
			get: function (key) {

				return objects[key];

			},
			add: function (key, object) {

				objects[key] = object;

			},
			remove: function (key) {

				delete objects[key];

			},
			removeAll: function () {

				objects = {};

			}
		};

	}
	/*********************************/

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

	/*********************************/


	const EXTENSIONS = {
		KHR_BINARY_GLTF: 'KHR_binary_glTF',
		KHR_DRACO_MESH_COMPRESSION: 'KHR_draco_mesh_compression',
		KHR_LIGHTS_PUNCTUAL: 'KHR_lights_punctual',
		KHR_MATERIALS_CLEARCOAT: 'KHR_materials_clearcoat',
		KHR_MATERIALS_IOR: 'KHR_materials_ior',
		KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS: 'KHR_materials_pbrSpecularGlossiness',
		KHR_MATERIALS_SPECULAR: 'KHR_materials_specular',
		KHR_MATERIALS_TRANSMISSION: 'KHR_materials_transmission',
		KHR_MATERIALS_UNLIT: 'KHR_materials_unlit',
		KHR_MATERIALS_VOLUME: 'KHR_materials_volume',
		KHR_TEXTURE_BASISU: 'KHR_texture_basisu',
		KHR_TEXTURE_TRANSFORM: 'KHR_texture_transform',
		KHR_MESH_QUANTIZATION: 'KHR_mesh_quantization',
		EXT_TEXTURE_WEBP: 'EXT_texture_webp',
		EXT_MESHOPT_COMPRESSION: 'EXT_meshopt_compression'
	};
	/**
 * Punctual Lights Extension
 *
 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_lights_punctual
 */

	class GLTFLightsExtension {

		constructor(parser) {

			this.parser = parser;
			this.name = EXTENSIONS.KHR_LIGHTS_PUNCTUAL; // THREE.Object3D instance caches

			this.cache = {
				refs: {},
				uses: {}
			};

		}

		_markDefs() {

			const parser = this.parser;
			const nodeDefs = this.parser.json.nodes || [];

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

				const nodeDef = nodeDefs[nodeIndex];

				if (nodeDef.extensions && nodeDef.extensions[this.name] && nodeDef.extensions[this.name].light !== undefined) {

					parser._addNodeRef(this.cache, nodeDef.extensions[this.name].light);

				}

			}

		}

		_loadLight(lightIndex) {

			const parser = this.parser;
			const cacheKey = 'light:' + lightIndex;
			let dependency = parser.cache.get(cacheKey);
			if (dependency) return dependency;
			const json = parser.json;
			const extensions = json.extensions && json.extensions[this.name] || {};
			const lightDefs = extensions.lights || [];
			const lightDef = lightDefs[lightIndex];
			let lightNode;
			const color = new THREE.Color(0xffffff);
			if (lightDef.color !== undefined) color.fromArray(lightDef.color);
			const range = lightDef.range !== undefined ? lightDef.range : 0;

			switch (lightDef.type) {

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

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

				case 'spot':
					lightNode = new THREE.SpotLight(color);
					lightNode.distance = range; // Handle spotlight properties.

					lightDef.spot = lightDef.spot || {};
					lightDef.spot.innerConeAngle = lightDef.spot.innerConeAngle !== undefined ? lightDef.spot.innerConeAngle : 0;
					lightDef.spot.outerConeAngle = lightDef.spot.outerConeAngle !== undefined ? lightDef.spot.outerConeAngle : Math.PI / 4.0;
					lightNode.angle = lightDef.spot.outerConeAngle;
					lightNode.penumbra = 1.0 - lightDef.spot.innerConeAngle / lightDef.spot.outerConeAngle;
					lightNode.target.position.set(0, 0, - 1);
					lightNode.add(lightNode.target);
					break;

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

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


			lightNode.position.set(0, 0, 0);
			lightNode.decay = 2;
			if (lightDef.intensity !== undefined) lightNode.intensity = lightDef.intensity;
			lightNode.name = parser.createUniqueName(lightDef.name || 'light_' + lightIndex);
			dependency = Promise.resolve(lightNode);
			parser.cache.add(cacheKey, dependency);
			return dependency;

		}

		createNodeAttachment(nodeIndex) {

			const self = this;
			const parser = this.parser;
			const json = parser.json;
			const nodeDef = json.nodes[nodeIndex];
			const lightDef = nodeDef.extensions && nodeDef.extensions[this.name] || {};
			const lightIndex = lightDef.light;
			if (lightIndex === undefined) return null;
			return this._loadLight(lightIndex).then(function (light) {

				return parser._getNodeRef(self.cache, lightIndex, light);

			});

		}

	}
	/**
 * Unlit Materials Extension
 *
 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_materials_unlit
 */


	class GLTFMaterialsUnlitExtension {

		constructor() {

			this.name = EXTENSIONS.KHR_MATERIALS_UNLIT;

		}

		getMaterialType() {

			return THREE.MeshBasicMaterial;

		}

		extendParams(materialParams, materialDef, parser) {

			const pending = [];
			materialParams.color = new THREE.Color(1.0, 1.0, 1.0);
			materialParams.opacity = 1.0;
			const metallicRoughness = materialDef.pbrMetallicRoughness;

			if (metallicRoughness) {

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

					const array = metallicRoughness.baseColorFactor;
					materialParams.color.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
 */


	class GLTFMaterialsClearcoatExtension {

		constructor(parser) {

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

		}

		getMaterialType(materialIndex) {

			const parser = this.parser;
			const materialDef = parser.json.materials[materialIndex];
			if (!materialDef.extensions || !materialDef.extensions[this.name]) return null;
			return THREE.MeshPhysicalMaterial;

		}

		extendMaterialParams(materialIndex, materialParams) {

			const parser = this.parser;
			const materialDef = parser.json.materials[materialIndex];

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

				return Promise.resolve();

			}

			const pending = [];
			const extension = materialDef.extensions[this.name];

			if (extension.clearcoatFactor !== undefined) {

				materialParams.clearcoat = extension.clearcoatFactor;

			}

			if (extension.clearcoatTexture !== undefined) {

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

			}

			if (extension.clearcoatRoughnessFactor !== undefined) {

				materialParams.clearcoatRoughness = extension.clearcoatRoughnessFactor;

			}

			if (extension.clearcoatRoughnessTexture !== undefined) {

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

			}

			if (extension.clearcoatNormalTexture !== undefined) {

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

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

					const scale = extension.clearcoatNormalTexture.scale; // https://github.com/mrdoob/three.js/issues/11438#issuecomment-507003995

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

				}

			}

			return Promise.all(pending);

		}

	}
	/**
 * Transmission Materials Extension
 *
 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_materials_transmission
 * Draft: https://github.com/KhronosGroup/glTF/pull/1698
 */


	class GLTFMaterialsTransmissionExtension {

		constructor(parser) {

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

		}

		getMaterialType(materialIndex) {

			const parser = this.parser;
			const materialDef = parser.json.materials[materialIndex];
			if (!materialDef.extensions || !materialDef.extensions[this.name]) return null;
			return THREE.MeshPhysicalMaterial;

		}

		extendMaterialParams(materialIndex, materialParams) {

			const parser = this.parser;
			const materialDef = parser.json.materials[materialIndex];

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

				return Promise.resolve();

			}

			const pending = [];
			const extension = materialDef.extensions[this.name];

			if (extension.transmissionFactor !== undefined) {

				materialParams.transmission = extension.transmissionFactor;

			}

			if (extension.transmissionTexture !== undefined) {

				pending.push(parser.assignTexture(materialParams, 'transmissionMap', extension.transmissionTexture));

			}

			return Promise.all(pending);

		}

	}
	/**
 * Materials Volume Extension
 *
 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_materials_volume
 */


	class GLTFMaterialsVolumeExtension {

		constructor(parser) {

			this.parser = parser;
			this.name = EXTENSIONS.KHR_MATERIALS_VOLUME;

		}

		getMaterialType(materialIndex) {

			const parser = this.parser;
			const materialDef = parser.json.materials[materialIndex];
			if (!materialDef.extensions || !materialDef.extensions[this.name]) return null;
			return THREE.MeshPhysicalMaterial;

		}

		extendMaterialParams(materialIndex, materialParams) {

			const parser = this.parser;
			const materialDef = parser.json.materials[materialIndex];

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

				return Promise.resolve();

			}

			const pending = [];
			const extension = materialDef.extensions[this.name];
			materialParams.thickness = extension.thicknessFactor !== undefined ? extension.thicknessFactor : 0;

			if (extension.thicknessTexture !== undefined) {

				pending.push(parser.assignTexture(materialParams, 'thicknessMap', extension.thicknessTexture));

			}

			materialParams.attenuationDistance = extension.attenuationDistance || 0;
			const colorArray = extension.attenuationColor || [1, 1, 1];
			materialParams.attenuationTint = new THREE.Color(colorArray[0], colorArray[1], colorArray[2]);
			return Promise.all(pending);

		}

	}
	/**
 * Materials ior Extension
 *
 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_materials_ior
 */


	class GLTFMaterialsIorExtension {

		constructor(parser) {

			this.parser = parser;
			this.name = EXTENSIONS.KHR_MATERIALS_IOR;

		}

		getMaterialType(materialIndex) {

			const parser = this.parser;
			const materialDef = parser.json.materials[materialIndex];
			if (!materialDef.extensions || !materialDef.extensions[this.name]) return null;
			return THREE.MeshPhysicalMaterial;

		}

		extendMaterialParams(materialIndex, materialParams) {

			const parser = this.parser;
			const materialDef = parser.json.materials[materialIndex];

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

				return Promise.resolve();

			}

			const extension = materialDef.extensions[this.name];
			materialParams.ior = extension.ior !== undefined ? extension.ior : 1.5;
			return Promise.resolve();

		}

	}
	/**
 * Materials specular Extension
 *
 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_materials_specular
 */


	class GLTFMaterialsSpecularExtension {

		constructor(parser) {

			this.parser = parser;
			this.name = EXTENSIONS.KHR_MATERIALS_SPECULAR;

		}

		getMaterialType(materialIndex) {

			const parser = this.parser;
			const materialDef = parser.json.materials[materialIndex];
			if (!materialDef.extensions || !materialDef.extensions[this.name]) return null;
			return THREE.MeshPhysicalMaterial;

		}

		extendMaterialParams(materialIndex, materialParams) {

			const parser = this.parser;
			const materialDef = parser.json.materials[materialIndex];

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

				return Promise.resolve();

			}

			const pending = [];
			const extension = materialDef.extensions[this.name];
			materialParams.specularIntensity = extension.specularFactor !== undefined ? extension.specularFactor : 1.0;

			if (extension.specularTexture !== undefined) {

				pending.push(parser.assignTexture(materialParams, 'specularIntensityMap', extension.specularTexture));

			}

			const colorArray = extension.specularColorFactor || [1, 1, 1];
			materialParams.specularTint = new THREE.Color(colorArray[0], colorArray[1], colorArray[2]);

			if (extension.specularColorTexture !== undefined) {

				pending.push(parser.assignTexture(materialParams, 'specularTintMap', extension.specularColorTexture).then(function (texture) {

					texture.encoding = THREE.sRGBEncoding;

				}));

			}

			return Promise.all(pending);

		}

	}
	/**
 * BasisU THREE.Texture Extension
 *
 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_texture_basisu
 */


	class GLTFTextureBasisUExtension {

		constructor(parser) {

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

		}

		loadTexture(textureIndex) {

			const parser = this.parser;
			const json = parser.json;
			const textureDef = json.textures[textureIndex];

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

				return null;

			}

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

			if (!loader) {

				if (json.extensionsRequired && json.extensionsRequired.indexOf(this.name) >= 0) {

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

				} else {

					// Assumes that the extension is optional and that a fallback texture is present
					return null;

				}

			}

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

		}

	}
	/**
 * WebP THREE.Texture Extension
 *
 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Vendor/EXT_texture_webp
 */


	class GLTFTextureWebPExtension {

		constructor(parser) {

			this.parser = parser;
			this.name = EXTENSIONS.EXT_TEXTURE_WEBP;
			this.isSupported = null;

		}

		loadTexture(textureIndex) {

			const name = this.name;
			const parser = this.parser;
			const json = parser.json;
			const textureDef = json.textures[textureIndex];

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

				return null;

			}

			const extension = textureDef.extensions[name];
			const source = json.images[extension.source];
			let loader = parser.textureLoader;

			if (source.uri) {

				const handler = parser.options.manager.getHandler(source.uri);
				if (handler !== null) loader = handler;

			}

			return this.detectSupport().then(function (isSupported) {

				if (isSupported) return parser.loadTextureImage(textureIndex, source, loader);

				if (json.extensionsRequired && json.extensionsRequired.indexOf(name) >= 0) {

					throw new Error('THREE.GLTFLoader: WebP required by asset but unsupported.');

				} // Fall back to PNG or JPEG.


				return parser.loadTexture(textureIndex);

			});

		}

		detectSupport() {

			if (!this.isSupported) {

				this.isSupported = new Promise(function (resolve) {

					const image = new Image(); // Lossy test image. Support for lossy images doesn't guarantee support for all
					// WebP images, unfortunately.

					image.src = 'data:image/webp;base64,UklGRiIAAABXRUJQVlA4IBYAAAAwAQCdASoBAAEADsD+JaQAA3AAAAAA';

					image.onload = image.onerror = function () {

						resolve(image.height === 1);

					};

				});

			}

			return this.isSupported;

		}

	}
	/**
 * meshopt BufferView Compression Extension
 *
 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Vendor/EXT_meshopt_compression
 */


	class GLTFMeshoptCompression {

		constructor(parser) {

			this.name = EXTENSIONS.EXT_MESHOPT_COMPRESSION;
			this.parser = parser;

		}

		loadBufferView(index) {

			const json = this.parser.json;
			const bufferView = json.bufferViews[index];

			if (bufferView.extensions && bufferView.extensions[this.name]) {

				const extensionDef = bufferView.extensions[this.name];
				const buffer = this.parser.getDependency('buffer', extensionDef.buffer);
				const decoder = this.parser.options.meshoptDecoder;

				if (!decoder || !decoder.supported) {

					if (json.extensionsRequired && json.extensionsRequired.indexOf(this.name) >= 0) {

						throw new Error('THREE.GLTFLoader: setMeshoptDecoder must be called before loading compressed files');

					} else {

						// Assumes that the extension is optional and that fallback buffer data is present
						return null;

					}

				}

				return Promise.all([buffer, decoder.ready]).then(function (res) {

					const byteOffset = extensionDef.byteOffset || 0;
					const byteLength = extensionDef.byteLength || 0;
					const count = extensionDef.count;
					const stride = extensionDef.byteStride;
					const result = new ArrayBuffer(count * stride);
					const source = new Uint8Array(res[0], byteOffset, byteLength);
					decoder.decodeGltfBuffer(new Uint8Array(result), count, stride, source, extensionDef.mode, extensionDef.filter);
					return result;

				});

			} else {

				return null;

			}

		}

	}
	/* BINARY EXTENSION */


	const BINARY_EXTENSION_HEADER_MAGIC = 'glTF';
	const BINARY_EXTENSION_HEADER_LENGTH = 12;
	const BINARY_EXTENSION_CHUNK_TYPES = {
		JSON: 0x4E4F534A,
		BIN: 0x004E4942
	};

	class GLTFBinaryExtension {

		constructor(data) {

			this.name = EXTENSIONS.KHR_BINARY_GLTF;
			this.content = null;
			this.body = null;
			const headerView = new DataView(data, 0, BINARY_EXTENSION_HEADER_LENGTH);
			this.header = {
				magic: THREE.LoaderUtils.decodeText(new Uint8Array(data.slice(0, 4))),
				version: headerView.getUint32(4, true),
				length: headerView.getUint32(8, true)
			};

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

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

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

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

			}

			const chunkContentsLength = this.header.length - BINARY_EXTENSION_HEADER_LENGTH;
			const chunkView = new DataView(data, BINARY_EXTENSION_HEADER_LENGTH);
			let chunkIndex = 0;

			while (chunkIndex < chunkContentsLength) {

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

				if (chunkType === BINARY_EXTENSION_CHUNK_TYPES.JSON) {

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

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

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

				} // Clients must ignore chunks with unknown types.


				chunkIndex += chunkLength;

			}

			if (this.content === null) {

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

			}

		}

	}
	/**
 * DRACO THREE.Mesh Compression Extension
 *
 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_draco_mesh_compression
 */


	class GLTFDracoMeshCompressionExtension {

		constructor(json, dracoLoader) {

			if (!dracoLoader) {

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

			}

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

		}

		decodePrimitive(primitive, parser) {

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

			for (const attributeName in gltfAttributeMap) {

				const threeAttributeName = ATTRIBUTES[attributeName] || attributeName.toLowerCase();
				threeAttributeMap[threeAttributeName] = gltfAttributeMap[attributeName];

			}

			for (const attributeName in primitive.attributes) {

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

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

					const accessorDef = json.accessors[primitive.attributes[attributeName]];
					const componentType = WEBGL_COMPONENT_TYPES[accessorDef.componentType];
					attributeTypeMap[threeAttributeName] = componentType;
					attributeNormalizedMap[threeAttributeName] = accessorDef.normalized === true;

				}

			}

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

				return new Promise(function (resolve) {

					dracoLoader.decodeDracoFile(bufferView, function (geometry) {

						for (const attributeName in geometry.attributes) {

							const attribute = geometry.attributes[attributeName];
							const normalized = attributeNormalizedMap[attributeName];
							if (normalized !== undefined) attribute.normalized = normalized;

						}

						resolve(geometry);

					}, threeAttributeMap, attributeTypeMap);

				});

			});

		}

	}
	/**
 * THREE.Texture Transform Extension
 *
 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_texture_transform
 */


	class GLTFTextureTransformExtension {

		constructor() {

			this.name = EXTENSIONS.KHR_TEXTURE_TRANSFORM;

		}

		extendTexture(texture, transform) {

			if (transform.texCoord !== undefined) {

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

			}

			if (transform.offset === undefined && transform.rotation === undefined && transform.scale === undefined) {

				// See https://github.com/mrdoob/three.js/issues/21819.
				return texture;

			}

			texture = texture.clone();

			if (transform.offset !== undefined) {

				texture.offset.fromArray(transform.offset);

			}

			if (transform.rotation !== undefined) {

				texture.rotation = transform.rotation;

			}

			if (transform.scale !== undefined) {

				texture.repeat.fromArray(transform.scale);

			}

			texture.needsUpdate = true;
			return texture;

		}

	}
	/**
 * 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
 */


	class GLTFMeshStandardSGMaterial extends THREE.MeshStandardMaterial {

		constructor(params) {

			super();
			this.isGLTFSpecularGlossinessMaterial = true; //various chunks that need replacing

			const specularMapParsFragmentChunk = ['#ifdef USE_SPECULARMAP', '	uniform sampler2D specularMap;', '#endif'].join('\n');
			const glossinessMapParsFragmentChunk = ['#ifdef USE_GLOSSINESSMAP', '	uniform sampler2D glossinessMap;', '#endif'].join('\n');
			const 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');
			const 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');
			const lightPhysicalFragmentChunk = ['PhysicalMaterial material;', 'material.diffuseColor = diffuseColor.rgb * ( 1. - max( specularFactor.r, max( specularFactor.g, specularFactor.b ) ) );', 'vec3 dxy = max( abs( dFdx( geometryNormal ) ), abs( dFdy( geometryNormal ) ) );', 'float geometryRoughness = max( max( dxy.x, dxy.y ), dxy.z );', 'material.roughness = max( 1.0 - glossinessFactor, 0.0525 ); // 0.0525 corresponds to the base mip of a 256 cubemap.', 'material.roughness += geometryRoughness;', 'material.roughness = min( material.roughness, 1.0 );', 'material.specularColor = specularFactor;'].join('\n');
			const uniforms = {
				specular: {
					value: new THREE.Color().setHex(0xffffff)
				},
				glossiness: {
					value: 1
				},
				specularMap: {
					value: null
				},
				glossinessMap: {
					value: null
				}
			};
			this._extraUniforms = uniforms;

			this.onBeforeCompile = function (shader) {

				for (const uniformName in uniforms) {

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

				}

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

			};

			Object.defineProperties(this, {
				specular: {
					get: function () {

						return uniforms.specular.value;

					},
					set: function (v) {

						uniforms.specular.value = v;

					}
				},
				specularMap: {
					get: function () {

						return uniforms.specularMap.value;

					},
					set: function (v) {

						uniforms.specularMap.value = v;

						if (v) {

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

						} else {

							delete this.defines.USE_SPECULARMAP;

						}

					}
				},
				glossiness: {
					get: function () {

						return uniforms.glossiness.value;

					},
					set: function (v) {

						uniforms.glossiness.value = v;

					}
				},
				glossinessMap: {
					get: function () {

						return uniforms.glossinessMap.value;

					},
					set: function (v) {

						uniforms.glossinessMap.value = v;

						if (v) {

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

						} else {

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

						}

					}
				}
			});
			delete this.metalness;
			delete this.roughness;
			delete this.metalnessMap;
			delete this.roughnessMap;
			this.setValues(params);

		}

		copy(source) {

			super.copy(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;

		}

	}

	class GLTFMaterialsPbrSpecularGlossinessExtension {

		constructor() {

			this.name = EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS;
			this.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() {

			return GLTFMeshStandardSGMaterial;

		}

		extendParams(materialParams, materialDef, parser) {

			const pbrSpecularGlossiness = materialDef.extensions[this.name];
			materialParams.color = new THREE.Color(1.0, 1.0, 1.0);
			materialParams.opacity = 1.0;
			const pending = [];

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

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

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

				materialParams.specular.fromArray(pbrSpecularGlossiness.specularFactor);

			}

			if (pbrSpecularGlossiness.specularGlossinessTexture !== undefined) {

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

			}

			return Promise.all(pending);

		}

		createMaterial(materialParams) {

			const 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 = THREE.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;

		}

	}
	/**
 * THREE.Mesh Quantization Extension
 *
 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_mesh_quantization
 */


	class GLTFMeshQuantizationExtension {

		constructor() {

			this.name = EXTENSIONS.KHR_MESH_QUANTIZATION;

		}

	}
	/*********************************/

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

	/*********************************/
	// Spline Interpolation
	// Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#appendix-c-spline-interpolation


	class GLTFCubicSplineInterpolant extends THREE.Interpolant {

		constructor(parameterPositions, sampleValues, sampleSize, resultBuffer) {

			super(parameterPositions, sampleValues, sampleSize, resultBuffer);

		}

		copySampleValue_(index) {

			// Copies a sample value to the result buffer. See description of glTF
			// CUBICSPLINE values layout in interpolate_() function below.
			const result = this.resultBuffer,
				values = this.sampleValues,
				valueSize = this.valueSize,
				offset = index * valueSize * 3 + valueSize;

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

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

			}

			return result;

		}

	}

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

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

		const result = this.resultBuffer;
		const values = this.sampleValues;
		const stride = this.valueSize;
		const stride2 = stride * 2;
		const stride3 = stride * 3;
		const td = t1 - t0;
		const p = (t - t0) / td;
		const pp = p * p;
		const ppp = pp * p;
		const offset1 = i1 * stride3;
		const offset0 = offset1 - stride3;
		const s2 = - 2 * ppp + 3 * pp;
		const s3 = ppp - pp;
		const s0 = 1 - s2;
		const s1 = s3 - pp + p; // Layout of keyframe output values for CUBICSPLINE animations:
		//   [ inTangent_1, splineVertex_1, outTangent_1, inTangent_2, splineVertex_2, ... ]

		for (let i = 0; i !== stride; i++) {

			const p0 = values[offset0 + i + stride]; // splineVertex_k

			const m0 = values[offset0 + i + stride2] * td; // outTangent_k * (t_k+1 - t_k)

			const p1 = values[offset1 + i + stride]; // splineVertex_k+1

			const m1 = values[offset1 + i] * td; // inTangent_k+1 * (t_k+1 - t_k)

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

		}

		return result;

	};

	const _q = new THREE.Quaternion();

	class GLTFCubicSplineQuaternionInterpolant extends GLTFCubicSplineInterpolant {

		interpolate_(i1, t0, t, t1) {

			const result = super.interpolate_(i1, t0, t, t1);

			_q.fromArray(result).normalize().toArray(result);

			return result;

		}

	}
	/*********************************/

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

	/*********************************/

	/* CONSTANTS */


	const WEBGL_CONSTANTS = {
		FLOAT: 5126,
		//FLOAT_MAT2: 35674,
		FLOAT_MAT3: 35675,
		FLOAT_MAT4: 35676,
		FLOAT_VEC2: 35664,
		FLOAT_VEC3: 35665,
		FLOAT_VEC4: 35666,
		LINEAR: 9729,
		REPEAT: 10497,
		SAMPLER_2D: 35678,
		POINTS: 0,
		LINES: 1,
		LINE_LOOP: 2,
		LINE_STRIP: 3,
		TRIANGLES: 4,
		TRIANGLE_STRIP: 5,
		TRIANGLE_FAN: 6,
		UNSIGNED_BYTE: 5121,
		UNSIGNED_SHORT: 5123
	};
	const WEBGL_COMPONENT_TYPES = {
		5120: Int8Array,
		5121: Uint8Array,
		5122: Int16Array,
		5123: Uint16Array,
		5125: Uint32Array,
		5126: Float32Array
	};
	const WEBGL_FILTERS = {
		9728: THREE.NearestFilter,
		9729: THREE.LinearFilter,
		9984: THREE.NearestMipmapNearestFilter,
		9985: THREE.LinearMipmapNearestFilter,
		9986: THREE.NearestMipmapLinearFilter,
		9987: THREE.LinearMipmapLinearFilter
	};
	const WEBGL_WRAPPINGS = {
		33071: THREE.ClampToEdgeWrapping,
		33648: THREE.MirroredRepeatWrapping,
		10497: THREE.RepeatWrapping
	};
	const WEBGL_TYPE_SIZES = {
		'SCALAR': 1,
		'VEC2': 2,
		'VEC3': 3,
		'VEC4': 4,
		'MAT2': 4,
		'MAT3': 9,
		'MAT4': 16
	};
	const ATTRIBUTES = {
		POSITION: 'position',
		NORMAL: 'normal',
		TANGENT: 'tangent',
		TEXCOORD_0: 'uv',
		TEXCOORD_1: 'uv2',
		COLOR_0: 'color',
		WEIGHTS_0: 'skinWeight',
		JOINTS_0: 'skinIndex'
	};
	const PATH_PROPERTIES = {
		scale: 'scale',
		translation: 'position',
		rotation: 'quaternion',
		weights: 'morphTargetInfluences'
	};
	const INTERPOLATION = {
		CUBICSPLINE: undefined,
		// We use a custom interpolant (GLTFCubicSplineInterpolation) for CUBICSPLINE tracks. Each
		// keyframe track will be initialized with a default interpolation type, then modified.
		LINEAR: THREE.InterpolateLinear,
		STEP: THREE.InterpolateDiscrete
	};
	const ALPHA_MODES = {
		OPAQUE: 'OPAQUE',
		MASK: 'MASK',
		BLEND: 'BLEND'
	};
	/* UTILITY FUNCTIONS */

	function resolveURL(url, path) {

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

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

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

		} // Absolute URL http://,https://,//


		if (/^(https?:)?\/\//i.test(url)) return url; // Data URI

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

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

		return path + url;

	}
	/**
 * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#default-material
 */


	function createDefaultMaterial(cache) {

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

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

		}

		return cache['DefaultMaterial'];

	}

	function addUnknownExtensionsToUserData(knownExtensions, object, objectDef) {

		// Add unknown glTF extensions to an object's userData.
		for (const name in objectDef.extensions) {

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

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

			}

		}

	}
	/**
 * @param {Object3D|Material|BufferGeometry} object
 * @param {GLTF.definition} gltfDef
 */


	function assignExtrasToUserData(object, gltfDef) {

		if (gltfDef.extras !== undefined) {

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

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

			} else {

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

			}

		}

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


	function addMorphTargets(geometry, targets, parser) {

		let hasMorphPosition = false;
		let hasMorphNormal = false;

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

			const target = targets[i];
			if (target.POSITION !== undefined) hasMorphPosition = true;
			if (target.NORMAL !== undefined) hasMorphNormal = true;
			if (hasMorphPosition && hasMorphNormal) break;

		}

		if (!hasMorphPosition && !hasMorphNormal) return Promise.resolve(geometry);
		const pendingPositionAccessors = [];
		const pendingNormalAccessors = [];

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

			const target = targets[i];

			if (hasMorphPosition) {

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

			}

			if (hasMorphNormal) {

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

			}

		}

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

			const morphPositions = accessors[0];
			const 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 (let i = 0, il = meshDef.weights.length; i < il; i++) {

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

			}

		} // .extras has user-defined data, so check that .extras.targetNames is an array.


		if (meshDef.extras && Array.isArray(meshDef.extras.targetNames)) {

			const targetNames = meshDef.extras.targetNames;

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

				mesh.morphTargetDictionary = {};

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

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

				}

			} else {

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

			}

		}

	}

	function createPrimitiveKey(primitiveDef) {

		const dracoExtension = primitiveDef.extensions && primitiveDef.extensions[EXTENSIONS.KHR_DRACO_MESH_COMPRESSION];
		let 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) {

		let attributesKey = '';
		const keys = Object.keys(attributes).sort();

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

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

		}

		return attributesKey;

	}

	function getNormalizedComponentScale(constructor) {

		// Reference:
		// https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_mesh_quantization#encoding-quantized-data
		switch (constructor) {

			case Int8Array:
				return 1 / 127;

			case Uint8Array:
				return 1 / 255;

			case Int16Array:
				return 1 / 32767;

			case Uint16Array:
				return 1 / 65535;

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

		}

	}
	/* GLTF PARSER */


	class GLTFParser {

		constructor(json = {}, options = {}) {

			this.json = json;
			this.extensions = {};
			this.plugins = {};
			this.options = options; // loader object cache

			this.cache = new GLTFRegistry(); // associations between Three.js objects and glTF elements

			this.associations = new Map(); // THREE.BufferGeometry caching

			this.primitiveCache = {}; // THREE.Object3D instance caches

			this.meshCache = {
				refs: {},
				uses: {}
			};
			this.cameraCache = {
				refs: {},
				uses: {}
			};
			this.lightCache = {
				refs: {},
				uses: {}
			};
			this.textureCache = {}; // Track node names, to ensure no duplicates

			this.nodeNamesUsed = {}; // Use an THREE.ImageBitmapLoader if imageBitmaps are supported. Moves much of the
			// expensive work of uploading a texture to the GPU off the main thread.

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

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

			} else {

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

			}

			this.textureLoader.setCrossOrigin(this.options.crossOrigin);
			this.textureLoader.setRequestHeader(this.options.requestHeader);
			this.fileLoader = new THREE.FileLoader(this.options.manager);
			this.fileLoader.setResponseType('arraybuffer');

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

				this.fileLoader.setWithCredentials(true);

			}

		}

		setExtensions(extensions) {

			this.extensions = extensions;

		}

		setPlugins(plugins) {

			this.plugins = plugins;

		}

		parse(onLoad, onError) {

			const parser = this;
			const json = this.json;
			const extensions = this.extensions; // Clear the loader cache

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

			this._invokeAll(function (ext) {

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

			});

			Promise.all(this._invokeAll(function (ext) {

				return ext.beforeRoot && ext.beforeRoot();

			})).then(function () {

				return Promise.all([parser.getDependencies('scene'), parser.getDependencies('animation'), parser.getDependencies('camera')]);

			}).then(function (dependencies) {

				const result = {
					scene: dependencies[0][json.scene || 0],
					scenes: dependencies[0],
					animations: dependencies[1],
					cameras: dependencies[2],
					asset: json.asset,
					parser: parser,
					userData: {}
				};
				addUnknownExtensionsToUserData(extensions, result, json);
				assignExtrasToUserData(result, json);
				Promise.all(parser._invokeAll(function (ext) {

					return ext.afterRoot && ext.afterRoot(result);

				})).then(function () {

					onLoad(result);

				});

			}).catch(onError);

		}
		/**
   * Marks the special nodes/meshes in json for efficient parse.
   */


		_markDefs() {

			const nodeDefs = this.json.nodes || [];
			const skinDefs = this.json.skins || [];
			const meshDefs = this.json.meshes || []; // Nothing in the node definition indicates whether it is a THREE.Bone or an
			// THREE.Object3D. Use the skins' joint references to mark bones.

			for (let skinIndex = 0, skinLength = skinDefs.length; skinIndex < skinLength; skinIndex++) {

				const joints = skinDefs[skinIndex].joints;

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

					nodeDefs[joints[i]].isBone = true;

				}

			} // Iterate over all nodes, marking references to shared resources,
			// as well as skeleton joints.


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

				const nodeDef = nodeDefs[nodeIndex];

				if (nodeDef.mesh !== undefined) {

					this._addNodeRef(this.meshCache, nodeDef.mesh); // Nothing in the mesh definition indicates whether it is
					// a THREE.SkinnedMesh or THREE.Mesh. Use the node's mesh reference
					// to mark THREE.SkinnedMesh if node has skin.


					if (nodeDef.skin !== undefined) {

						meshDefs[nodeDef.mesh].isSkinnedMesh = true;

					}

				}

				if (nodeDef.camera !== undefined) {

					this._addNodeRef(this.cameraCache, nodeDef.camera);

				}

			}

		}
		/**
   * Counts references to shared node / THREE.Object3D resources. These resources
   * can be reused, or "instantiated", at multiple nodes in the scene
   * hierarchy. THREE.Mesh, Camera, and Light instances are instantiated and must
   * be marked. Non-scenegraph resources (like Materials, Geometries, and
   * Textures) can be reused directly and are not marked here.
   *
   * Example: CesiumMilkTruck sample model reuses "Wheel" meshes.
   */


		_addNodeRef(cache, index) {

			if (index === undefined) return;

			if (cache.refs[index] === undefined) {

				cache.refs[index] = cache.uses[index] = 0;

			}

			cache.refs[index]++;

		}
		/** Returns a reference to a shared resource, cloning it if necessary. */


		_getNodeRef(cache, index, object) {

			if (cache.refs[index] <= 1) return object;
			const ref = object.clone();
			ref.name += '_instance_' + cache.uses[index]++;
			return ref;

		}

		_invokeOne(func) {

			const extensions = Object.values(this.plugins);
			extensions.push(this);

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

				const result = func(extensions[i]);
				if (result) return result;

			}

			return null;

		}

		_invokeAll(func) {

			const extensions = Object.values(this.plugins);
			extensions.unshift(this);
			const pending = [];

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

				const result = func(extensions[i]);
				if (result) pending.push(result);

			}

			return pending;

		}
		/**
   * Requests the specified dependency asynchronously, with caching.
   * @param {string} type
   * @param {number} index
   * @return {Promise<Object3D|Material|THREE.Texture|AnimationClip|ArrayBuffer|Object>}
   */


		getDependency(type, index) {

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

			if (!dependency) {

				switch (type) {

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

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

					case 'mesh':
						dependency = this._invokeOne(function (ext) {

							return ext.loadMesh && ext.loadMesh(index);

						});
						break;

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

					case 'bufferView':
						dependency = this._invokeOne(function (ext) {

							return ext.loadBufferView && ext.loadBufferView(index);

						});
						break;

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

					case 'material':
						dependency = this._invokeOne(function (ext) {

							return ext.loadMaterial && ext.loadMaterial(index);

						});
						break;

					case 'texture':
						dependency = this._invokeOne(function (ext) {

							return ext.loadTexture && ext.loadTexture(index);

						});
						break;

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

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

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

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

				}

				this.cache.add(cacheKey, dependency);

			}

			return dependency;

		}
		/**
   * Requests all dependencies of the specified type asynchronously, with caching.
   * @param {string} type
   * @return {Promise<Array<Object>>}
   */


		getDependencies(type) {

			let dependencies = this.cache.get(type);

			if (!dependencies) {

				const parser = this;
				const defs = this.json[type + (type === 'mesh' ? 'es' : 's')] || [];
				dependencies = Promise.all(defs.map(function (def, index) {

					return parser.getDependency(type, index);

				}));
				this.cache.add(type, dependencies);

			}

			return dependencies;

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


		loadBuffer(bufferIndex) {

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

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

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

			} // If present, GLB container is required to be the first buffer.


			if (bufferDef.uri === undefined && bufferIndex === 0) {

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

			}

			const options = this.options;
			return new Promise(function (resolve, reject) {

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

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

				});

			});

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


		loadBufferView(bufferViewIndex) {

			const bufferViewDef = this.json.bufferViews[bufferViewIndex];
			return this.getDependency('buffer', bufferViewDef.buffer).then(function (buffer) {

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

			});

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


		loadAccessor(accessorIndex) {

			const parser = this;
			const json = this.json;
			const accessorDef = this.json.accessors[accessorIndex];

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

				// 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);

			}

			const pendingBufferViews = [];

			if (accessorDef.bufferView !== undefined) {

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

			} else {

				pendingBufferViews.push(null);

			}

			if (accessorDef.sparse !== undefined) {

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

			}

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

				const bufferView = bufferViews[0];
				const itemSize = WEBGL_TYPE_SIZES[accessorDef.type];
				const TypedArray = WEBGL_COMPONENT_TYPES[accessorDef.componentType]; // For VEC3: itemSize is 3, elementBytes is 4, itemBytes is 12.

				const elementBytes = TypedArray.BYTES_PER_ELEMENT;
				const itemBytes = elementBytes * itemSize;
				const byteOffset = accessorDef.byteOffset || 0;
				const byteStride = accessorDef.bufferView !== undefined ? json.bufferViews[accessorDef.bufferView].byteStride : undefined;
				const normalized = accessorDef.normalized === true;
				let array, bufferAttribute; // The buffer is not interleaved if the stride is the item size in bytes.

				if (byteStride && byteStride !== itemBytes) {

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

					if (!ib) {

						array = new TypedArray(bufferView, ibSlice * byteStride, accessorDef.count * byteStride / elementBytes); // Integer parameters to IB/IBA are in array elements, not bytes.

						ib = new THREE.InterleavedBuffer(array, byteStride / elementBytes);
						parser.cache.add(ibCacheKey, ib);

					}

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

				} // https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#sparse-accessors


				if (accessorDef.sparse !== undefined) {

					const itemSizeIndices = WEBGL_TYPE_SIZES.SCALAR;
					const TypedArrayIndices = WEBGL_COMPONENT_TYPES[accessorDef.sparse.indices.componentType];
					const byteOffsetIndices = accessorDef.sparse.indices.byteOffset || 0;
					const byteOffsetValues = accessorDef.sparse.values.byteOffset || 0;
					const sparseIndices = new TypedArrayIndices(bufferViews[1], byteOffsetIndices, accessorDef.sparse.count * itemSizeIndices);
					const sparseValues = new TypedArray(bufferViews[2], byteOffsetValues, accessorDef.sparse.count * itemSize);

					if (bufferView !== null) {

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

					}

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

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

					}

				}

				return bufferAttribute;

			});

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


		loadTexture(textureIndex) {

			const json = this.json;
			const options = this.options;
			const textureDef = json.textures[textureIndex];
			const source = json.images[textureDef.source];
			let loader = this.textureLoader;

			if (source.uri) {

				const handler = options.manager.getHandler(source.uri);
				if (handler !== null) loader = handler;

			}

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

		}

		loadTextureImage(textureIndex, source, loader) {

			const parser = this;
			const json = this.json;
			const options = this.options;
			const textureDef = json.textures[textureIndex];
			const cacheKey = (source.uri || source.bufferView) + ':' + textureDef.sampler;

			if (this.textureCache[cacheKey]) {

				// See https://github.com/mrdoob/three.js/issues/21559.
				return this.textureCache[cacheKey];

			}

			const URL = self.URL || self.webkitURL;
			let sourceURI = source.uri || '';
			let isObjectURL = false;
			let hasAlpha = true;
			const isJPEG = sourceURI.search(/\.jpe?g($|\?)/i) > 0 || sourceURI.search(/^data\:image\/jpeg/) === 0;
			if (source.mimeType === 'image/jpeg' || isJPEG) hasAlpha = false;

			if (source.bufferView !== undefined) {

				// Load binary image data from bufferView, if provided.
				sourceURI = parser.getDependency('bufferView', source.bufferView).then(function (bufferView) {

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

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

					}

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

				});

			} else if (source.uri === undefined) {

				throw new Error('THREE.GLTFLoader: Image ' + textureIndex + ' is missing URI and bufferView');

			}

			const promise = Promise.resolve(sourceURI).then(function (sourceURI) {

				return new Promise(function (resolve, reject) {

					let onLoad = resolve;

					if (loader.isImageBitmapLoader === true) {

						onLoad = function (imageBitmap) {

							const texture = new THREE.Texture(imageBitmap);
							texture.needsUpdate = true;
							resolve(texture);

						};

					}

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

				});

			}).then(function (texture) {

				// Clean up resources and configure THREE.Texture.
				if (isObjectURL === true) {

					URL.revokeObjectURL(sourceURI);

				}

				texture.flipY = false;
				if (textureDef.name) texture.name = textureDef.name; // When there is definitely no alpha channel in the texture, set THREE.RGBFormat to save space.

				if (!hasAlpha) texture.format = THREE.RGBFormat;
				const samplers = json.samplers || {};
				const sampler = samplers[textureDef.sampler] || {};
				texture.magFilter = WEBGL_FILTERS[sampler.magFilter] || THREE.LinearFilter;
				texture.minFilter = WEBGL_FILTERS[sampler.minFilter] || THREE.LinearMipmapLinearFilter;
				texture.wrapS = WEBGL_WRAPPINGS[sampler.wrapS] || THREE.RepeatWrapping;
				texture.wrapT = WEBGL_WRAPPINGS[sampler.wrapT] || THREE.RepeatWrapping;
				parser.associations.set(texture, {
					type: 'textures',
					index: textureIndex
				});
				return texture;

			}).catch(function () {

				console.error('THREE.GLTFLoader: Couldn\'t load texture', sourceURI);
				return null;

			});
			this.textureCache[cacheKey] = promise;
			return promise;

		}
		/**
   * Asynchronously assigns a texture to the given material parameters.
   * @param {Object} materialParams
   * @param {string} mapName
   * @param {Object} mapDef
   * @return {Promise<Texture>}
   */


		assignTexture(materialParams, mapName, mapDef) {

			const parser = this;
			return this.getDependency('texture', mapDef.index).then(function (texture) {

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

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

				}

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

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

					if (transform) {

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

					}

				}

				materialParams[mapName] = texture;
				return texture;

			});

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


		assignFinalMaterial(mesh) {

			const geometry = mesh.geometry;
			let material = mesh.material;
			const useVertexTangents = geometry.attributes.tangent !== undefined;
			const useVertexColors = geometry.attributes.color !== undefined;
			const useFlatShading = geometry.attributes.normal === undefined;

			if (mesh.isPoints) {

				const cacheKey = 'PointsMaterial:' + material.uuid;
				let pointsMaterial = this.cache.get(cacheKey);

				if (!pointsMaterial) {

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

					this.cache.add(cacheKey, pointsMaterial);

				}

				material = pointsMaterial;

			} else if (mesh.isLine) {

				const cacheKey = 'LineBasicMaterial:' + material.uuid;
				let lineMaterial = this.cache.get(cacheKey);

				if (!lineMaterial) {

					lineMaterial = new THREE.LineBasicMaterial();
					THREE.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) {

				let cacheKey = 'ClonedMaterial:' + material.uuid + ':';
				if (material.isGLTFSpecularGlossinessMaterial) cacheKey += 'specular-glossiness:';
				if (useVertexTangents) cacheKey += 'vertex-tangents:';
				if (useVertexColors) cacheKey += 'vertex-colors:';
				if (useFlatShading) cacheKey += 'flat-shading:';
				let cachedMaterial = this.cache.get(cacheKey);

				if (!cachedMaterial) {

					cachedMaterial = material.clone();
					if (useVertexColors) cachedMaterial.vertexColors = true;
					if (useFlatShading) cachedMaterial.flatShading = true;

					if (useVertexTangents) {

						// https://github.com/mrdoob/three.js/issues/11438#issuecomment-507003995
						if (cachedMaterial.normalScale) cachedMaterial.normalScale.y *= - 1;
						if (cachedMaterial.clearcoatNormalScale) cachedMaterial.clearcoatNormalScale.y *= - 1;

					}

					this.cache.add(cacheKey, cachedMaterial);
					this.associations.set(cachedMaterial, this.associations.get(material));

				}

				material = cachedMaterial;

			} // workarounds for mesh and geometry


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

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

			}

			mesh.material = material;

		}

		getMaterialType() {

			return THREE.MeshStandardMaterial;

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


		loadMaterial(materialIndex) {

			const parser = this;
			const json = this.json;
			const extensions = this.extensions;
			const materialDef = json.materials[materialIndex];
			let materialType;
			const materialParams = {};
			const materialExtensions = materialDef.extensions || {};
			const pending = [];

			if (materialExtensions[EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS]) {

				const 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]) {

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

			} else {

				// Specification:
				// https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#metallic-roughness-material
				const metallicRoughness = materialDef.pbrMetallicRoughness || {};
				materialParams.color = new THREE.Color(1.0, 1.0, 1.0);
				materialParams.opacity = 1.0;

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

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

				}

				if (metallicRoughness.baseColorTexture !== undefined) {

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

				}

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

				if (metallicRoughness.metallicRoughnessTexture !== undefined) {

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

				}

				materialType = this._invokeOne(function (ext) {

					return ext.getMaterialType && ext.getMaterialType(materialIndex);

				});
				pending.push(Promise.all(this._invokeAll(function (ext) {

					return ext.extendMaterialParams && ext.extendMaterialParams(materialIndex, materialParams);

				})));

			}

			if (materialDef.doubleSided === true) {

				materialParams.side = THREE.DoubleSide;

			}

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

			if (alphaMode === ALPHA_MODES.BLEND) {

				materialParams.transparent = true; // See: https://github.com/mrdoob/three.js/issues/17706

				materialParams.depthWrite = false;

			} else {

				materialParams.format = THREE.RGBFormat;
				materialParams.transparent = false;

				if (alphaMode === ALPHA_MODES.MASK) {

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

				}

			}

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

				pending.push(parser.assignTexture(materialParams, 'normalMap', materialDef.normalTexture)); // https://github.com/mrdoob/three.js/issues/11438#issuecomment-507003995

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

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

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

				}

			}

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

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

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

					materialParams.aoMapIntensity = materialDef.occlusionTexture.strength;

				}

			}

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

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

			}

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

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

			}

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

				let 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 = THREE.sRGBEncoding;
				if (material.emissiveMap) material.emissiveMap.encoding = THREE.sRGBEncoding;
				assignExtrasToUserData(material, materialDef);
				parser.associations.set(material, {
					type: 'materials',
					index: materialIndex
				});
				if (materialDef.extensions) addUnknownExtensionsToUserData(extensions, material, materialDef);
				return material;

			});

		}
		/** When THREE.Object3D instances are targeted by animation, they need unique names. */


		createUniqueName(originalName) {

			const sanitizedName = THREE.PropertyBinding.sanitizeNodeName(originalName || '');
			let name = sanitizedName;

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

				name = sanitizedName + '_' + i;

			}

			this.nodeNamesUsed[name] = true;
			return name;

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


		loadGeometries(primitives) {

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

			function createDracoPrimitive(primitive) {

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

					return addPrimitiveAttributes(geometry, primitive, parser);

				});

			}

			const pending = [];

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

				const primitive = primitives[i];
				const cacheKey = createPrimitiveKey(primitive); // See if we've already created this geometry

				const cached = cache[cacheKey];

				if (cached) {

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

				} else {

					let geometryPromise;

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

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

					} else {

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

					} // Cache this geometry


					cache[cacheKey] = {
						primitive: primitive,
						promise: geometryPromise
					};
					pending.push(geometryPromise);

				}

			}

			return Promise.all(pending);

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


		loadMesh(meshIndex) {

			const parser = this;
			const json = this.json;
			const extensions = this.extensions;
			const meshDef = json.meshes[meshIndex];
			const primitives = meshDef.primitives;
			const pending = [];

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

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

			}

			pending.push(parser.loadGeometries(primitives));
			return Promise.all(pending).then(function (results) {

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

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

					const geometry = geometries[i];
					const primitive = primitives[i]; // 1. create THREE.Mesh

					let mesh;
					const material = materials[i];

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

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

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

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

						}

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

						mesh = new THREE.LineSegments(geometry, material);

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

						mesh = new THREE.Line(geometry, material);

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

						mesh = new THREE.LineLoop(geometry, material);

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

						mesh = new THREE.Points(geometry, material);

					} else {

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

					}

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

						updateMorphTargets(mesh, meshDef);

					}

					mesh.name = parser.createUniqueName(meshDef.name || 'mesh_' + meshIndex);
					assignExtrasToUserData(mesh, meshDef);
					if (primitive.extensions) addUnknownExtensionsToUserData(extensions, mesh, primitive);
					parser.assignFinalMaterial(mesh);
					meshes.push(mesh);

				}

				if (meshes.length === 1) {

					return meshes[0];

				}

				const group = new THREE.Group();

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

					group.add(meshes[i]);

				}

				return group;

			});

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


		loadCamera(cameraIndex) {

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

			if (!params) {

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

			}

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

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

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

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

			}

			if (cameraDef.name) camera.name = this.createUniqueName(cameraDef.name);
			assignExtrasToUserData(camera, cameraDef);
			return Promise.resolve(camera);

		}
		/**
   * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#skins
   * @param {number} skinIndex
   * @return {Promise<Object>}
   */


		loadSkin(skinIndex) {

			const skinDef = this.json.skins[skinIndex];
			const 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>}
   */


		loadAnimation(animationIndex) {

			const json = this.json;
			const animationDef = json.animations[animationIndex];
			const pendingNodes = [];
			const pendingInputAccessors = [];
			const pendingOutputAccessors = [];
			const pendingSamplers = [];
			const pendingTargets = [];

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

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

				const input = animationDef.parameters !== undefined ? animationDef.parameters[sampler.input] : sampler.input;
				const 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) {

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

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

					const node = nodes[i];
					const inputAccessor = inputAccessors[i];
					const outputAccessor = outputAccessors[i];
					const sampler = samplers[i];
					const target = targets[i];
					if (node === undefined) continue;
					node.updateMatrix();
					node.matrixAutoUpdate = true;
					let TypedKeyframeTrack;

					switch (PATH_PROPERTIES[target.path]) {

						case PATH_PROPERTIES.weights:
							TypedKeyframeTrack = THREE.NumberKeyframeTrack;
							break;

						case PATH_PROPERTIES.rotation:
							TypedKeyframeTrack = THREE.QuaternionKeyframeTrack;
							break;

						case PATH_PROPERTIES.position:
						case PATH_PROPERTIES.scale:
						default:
							TypedKeyframeTrack = THREE.VectorKeyframeTrack;
							break;

					}

					const targetName = node.name ? node.name : node.uuid;
					const interpolation = sampler.interpolation !== undefined ? INTERPOLATION[sampler.interpolation] : THREE.InterpolateLinear;
					const targetNames = [];

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

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

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

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

							}

						});

					} else {

						targetNames.push(targetName);

					}

					let outputArray = outputAccessor.array;

					if (outputAccessor.normalized) {

						const scale = getNormalizedComponentScale(outputArray.constructor);
						const scaled = new Float32Array(outputArray.length);

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

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

						}

						outputArray = scaled;

					}

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

						const track = new TypedKeyframeTrack(targetNames[j] + '.' + PATH_PROPERTIES[target.path], inputAccessor.array, outputArray, interpolation); // Override interpolation with custom factory method.

						if (sampler.interpolation === 'CUBICSPLINE') {

							track.createInterpolant = function InterpolantFactoryMethodGLTFCubicSpline(result) {

								// A CUBICSPLINE keyframe in glTF has three output values for each input value,
								// representing inTangent, splineVertex, and outTangent. As a result, track.getValueSize()
								// must be divided by three to get the interpolant's sampleSize argument.
								const interpolantType = this instanceof THREE.QuaternionKeyframeTrack ? GLTFCubicSplineQuaternionInterpolant : GLTFCubicSplineInterpolant;
								return new interpolantType(this.times, this.values, this.getValueSize() / 3, result);

							}; // Mark as CUBICSPLINE. `track.getInterpolation()` doesn't support custom interpolants.


							track.createInterpolant.isInterpolantFactoryMethodGLTFCubicSpline = true;

						}

						tracks.push(track);

					}

				}

				const name = animationDef.name ? animationDef.name : 'animation_' + animationIndex;
				return new THREE.AnimationClip(name, undefined, tracks);

			});

		}

		createNodeMesh(nodeIndex) {

			const json = this.json;
			const parser = this;
			const nodeDef = json.nodes[nodeIndex];
			if (nodeDef.mesh === undefined) return null;
			return parser.getDependency('mesh', nodeDef.mesh).then(function (mesh) {

				const node = parser._getNodeRef(parser.meshCache, nodeDef.mesh, mesh); // if weights are provided on the node, override weights on the mesh.


				if (nodeDef.weights !== undefined) {

					node.traverse(function (o) {

						if (!o.isMesh) return;

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

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

						}

					});

				}

				return node;

			});

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


		loadNode(nodeIndex) {

			const json = this.json;
			const extensions = this.extensions;
			const parser = this;
			const nodeDef = json.nodes[nodeIndex]; // reserve node's name before its dependencies, so the root has the intended name.

			const nodeName = nodeDef.name ? parser.createUniqueName(nodeDef.name) : '';
			return function () {

				const pending = [];

				const meshPromise = parser._invokeOne(function (ext) {

					return ext.createNodeMesh && ext.createNodeMesh(nodeIndex);

				});

				if (meshPromise) {

					pending.push(meshPromise);

				}

				if (nodeDef.camera !== undefined) {

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

						return parser._getNodeRef(parser.cameraCache, nodeDef.camera, camera);

					}));

				}

				parser._invokeAll(function (ext) {

					return ext.createNodeAttachment && ext.createNodeAttachment(nodeIndex);

				}).forEach(function (promise) {

					pending.push(promise);

				});

				return Promise.all(pending);

			}().then(function (objects) {

				let node; // .isBone isn't in glTF spec. See ._markDefs

				if (nodeDef.isBone === true) {

					node = new THREE.Bone();

				} else if (objects.length > 1) {

					node = new THREE.Group();

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

					node = objects[0];

				} else {

					node = new THREE.Object3D();

				}

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

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

						node.add(objects[i]);

					}

				}

				if (nodeDef.name) {

					node.userData.name = nodeDef.name;
					node.name = nodeName;

				}

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

				if (nodeDef.matrix !== undefined) {

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

				} else {

					if (nodeDef.translation !== undefined) {

						node.position.fromArray(nodeDef.translation);

					}

					if (nodeDef.rotation !== undefined) {

						node.quaternion.fromArray(nodeDef.rotation);

					}

					if (nodeDef.scale !== undefined) {

						node.scale.fromArray(nodeDef.scale);

					}

				}

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

			});

		}
		/**
   * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#scenes
   * @param {number} sceneIndex
   * @return {Promise<Group>}
   */


		loadScene(sceneIndex) {

			const json = this.json;
			const extensions = this.extensions;
			const sceneDef = this.json.scenes[sceneIndex];
			const parser = this; // THREE.Loader returns THREE.Group, not Scene.
			// See: https://github.com/mrdoob/three.js/issues/18342#issuecomment-578981172

			const scene = new THREE.Group();
			if (sceneDef.name) scene.name = parser.createUniqueName(sceneDef.name);
			assignExtrasToUserData(scene, sceneDef);
			if (sceneDef.extensions) addUnknownExtensionsToUserData(extensions, scene, sceneDef);
			const nodeIds = sceneDef.nodes || [];
			const pending = [];

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

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

			}

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

				return scene;

			});

		}

	}

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

		const nodeDef = json.nodes[nodeId];
		return parser.getDependency('node', nodeId).then(function (node) {

			if (nodeDef.skin === undefined) return node; // build skeleton here as well

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

				skinEntry = skin;
				const pendingJoints = [];

				for (let 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;
					const bones = [];
					const boneInverses = [];

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

						const jointNode = jointNodes[j];

						if (jointNode) {

							bones.push(jointNode);
							const mat = new THREE.Matrix4();

							if (skinEntry.inverseBindMatrices !== undefined) {

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

							}

							boneInverses.push(mat);

						} else {

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

						}

					}

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

				});
				return node;

			});

		}).then(function (node) {

			// build node hierachy
			parentObject.add(node);
			const pending = [];

			if (nodeDef.children) {

				const children = nodeDef.children;

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

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

				}

			}

			return Promise.all(pending);

		});

	}
	/**
 * @param {BufferGeometry} geometry
 * @param {GLTF.Primitive} primitiveDef
 * @param {GLTFParser} parser
 */


	function computeBounds(geometry, primitiveDef, parser) {

		const attributes = primitiveDef.attributes;
		const box = new THREE.Box3();

		if (attributes.POSITION !== undefined) {

			const accessor = parser.json.accessors[attributes.POSITION];
			const min = accessor.min;
			const max = accessor.max; // glTF requires 'min' and 'max', but VRM (which extends glTF) currently ignores that requirement.

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

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

				if (accessor.normalized) {

					const boxScale = getNormalizedComponentScale(WEBGL_COMPONENT_TYPES[accessor.componentType]);
					box.min.multiplyScalar(boxScale);
					box.max.multiplyScalar(boxScale);

				}

			} else {

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

			}

		} else {

			return;

		}

		const targets = primitiveDef.targets;

		if (targets !== undefined) {

			const maxDisplacement = new THREE.Vector3();
			const vector = new THREE.Vector3();

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

				const target = targets[i];

				if (target.POSITION !== undefined) {

					const accessor = parser.json.accessors[target.POSITION];
					const min = accessor.min;
					const max = accessor.max; // glTF requires 'min' and 'max', but VRM (which extends glTF) currently ignores that requirement.

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

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

						if (accessor.normalized) {

							const boxScale = getNormalizedComponentScale(WEBGL_COMPONENT_TYPES[accessor.componentType]);
							vector.multiplyScalar(boxScale);

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


						maxDisplacement.max(vector);

					} else {

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

					}

				}

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


			box.expandByVector(maxDisplacement);

		}

		geometry.boundingBox = box;
		const sphere = new THREE.Sphere();
		box.getCenter(sphere.center);
		sphere.radius = box.min.distanceTo(box.max) / 2;
		geometry.boundingSphere = sphere;

	}
	/**
 * @param {BufferGeometry} geometry
 * @param {GLTF.Primitive} primitiveDef
 * @param {GLTFParser} parser
 * @return {Promise<BufferGeometry>}
 */


	function addPrimitiveAttributes(geometry, primitiveDef, parser) {

		const attributes = primitiveDef.attributes;
		const pending = [];

		function assignAttributeAccessor(accessorIndex, attributeName) {

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

				geometry.setAttribute(attributeName, accessor);

			});

		}

		for (const gltfAttributeName in attributes) {

			const threeAttributeName = ATTRIBUTES[gltfAttributeName] || gltfAttributeName.toLowerCase(); // Skip attributes already provided by e.g. Draco extension.

			if (threeAttributeName in geometry.attributes) continue;
			pending.push(assignAttributeAccessor(attributes[gltfAttributeName], threeAttributeName));

		}

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

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

				geometry.setIndex(accessor);

			});
			pending.push(accessor);

		}

		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) {

		let index = geometry.getIndex(); // generate index if not present

		if (index === null) {

			const indices = [];
			const position = geometry.getAttribute('position');

			if (position !== undefined) {

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

					indices.push(i);

				}

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

			} else {

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

			}

		} //


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

		if (drawMode === THREE.TriangleFanDrawMode) {

			// gl.TRIANGLE_FAN
			for (let i = 1; i <= numberOfTriangles; i++) {

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

			}

		} else {

			// gl.TRIANGLE_STRIP
			for (let i = 0; i < numberOfTriangles; i++) {

				if (i % 2 === 0) {

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

				} else {

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

				}

			}

		}

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

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

		} // build final geometry


		const newGeometry = geometry.clone();
		newGeometry.setIndex(newIndices);
		return newGeometry;

	}

	THREE.GLTFLoader = GLTFLoader;

})();

module.exports = exports = THREE.GLTFLoader;