File: //var/www/aspa/three/addons/loaders/GLTFLoader.js
import {
	AnimationClip,
	Bone,
	Box3,
	BufferAttribute,
	BufferGeometry,
	ClampToEdgeWrapping,
	Color,
	ColorManagement,
	DirectionalLight,
	DoubleSide,
	FileLoader,
	FrontSide,
	Group,
	ImageBitmapLoader,
	InstancedMesh,
	InterleavedBuffer,
	InterleavedBufferAttribute,
	Interpolant,
	InterpolateDiscrete,
	InterpolateLinear,
	Line,
	LineBasicMaterial,
	LineLoop,
	LineSegments,
	LinearFilter,
	LinearMipmapLinearFilter,
	LinearMipmapNearestFilter,
	LinearSRGBColorSpace,
	Loader,
	LoaderUtils,
	Material,
	MathUtils,
	Matrix4,
	Mesh,
	MeshBasicMaterial,
	MeshPhysicalMaterial,
	MeshStandardMaterial,
	MirroredRepeatWrapping,
	NearestFilter,
	NearestMipmapLinearFilter,
	NearestMipmapNearestFilter,
	NumberKeyframeTrack,
	Object3D,
	OrthographicCamera,
	PerspectiveCamera,
	PointLight,
	Points,
	PointsMaterial,
	PropertyBinding,
	Quaternion,
	QuaternionKeyframeTrack,
	RepeatWrapping,
	Skeleton,
	SkinnedMesh,
	Sphere,
	SpotLight,
	Texture,
	TextureLoader,
	TriangleFanDrawMode,
	TriangleStripDrawMode,
	Vector2,
	Vector3,
	VectorKeyframeTrack,
	SRGBColorSpace,
	InstancedBufferAttribute
} from 'three';
import { toTrianglesDrawMode } from '../utils/BufferGeometryUtils.js';
class GLTFLoader extends 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 GLTFTextureAVIFExtension( parser );
		} );
		this.register( function ( parser ) {
			return new GLTFMaterialsSheenExtension( 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 GLTFMaterialsEmissiveStrengthExtension( parser );
		} );
		this.register( function ( parser ) {
			return new GLTFMaterialsSpecularExtension( parser );
		} );
		this.register( function ( parser ) {
			return new GLTFMaterialsIridescenceExtension( parser );
		} );
		this.register( function ( parser ) {
			return new GLTFMaterialsAnisotropyExtension( parser );
		} );
		this.register( function ( parser ) {
			return new GLTFMaterialsBumpExtension( parser );
		} );
		this.register( function ( parser ) {
			return new GLTFLightsExtension( parser );
		} );
		this.register( function ( parser ) {
			return new GLTFMeshoptCompression( parser );
		} );
		this.register( function ( parser ) {
			return new GLTFMeshGpuInstancing( parser );
		} );
	}
	load( url, onLoad, onProgress, onError ) {
		const scope = this;
		let resourcePath;
		if ( this.resourcePath !== '' ) {
			resourcePath = this.resourcePath;
		} else if ( this.path !== '' ) {
			// If a base path is set, resources will be relative paths from that plus the relative path of the gltf file
			// Example  path = 'https://my-cnd-server.com/', url = 'assets/models/model.gltf'
			// resourcePath = 'https://my-cnd-server.com/assets/models/'
			// referenced resource 'model.bin' will be loaded from 'https://my-cnd-server.com/assets/models/model.bin'
			// referenced resource '../textures/texture.png' will be loaded from 'https://my-cnd-server.com/assets/textures/texture.png'
			const relativeUrl = LoaderUtils.extractUrlBase( url );
			resourcePath = LoaderUtils.resolveURL( relativeUrl, this.path );
		} else {
			resourcePath = LoaderUtils.extractUrlBase( url );
		}
		// Tells the LoadingManager to track an extra item, which resolves after
		// the model is fully loaded. This means the count of items loaded will
		// be incorrect, but ensures manager.onLoad() does not fire early.
		this.manager.itemStart( url );
		const _onError = function ( e ) {
			if ( onError ) {
				onError( e );
			} else {
				console.error( e );
			}
			scope.manager.itemError( url );
			scope.manager.itemEnd( url );
		};
		const loader = new FileLoader( this.manager );
		loader.setPath( this.path );
		loader.setResponseType( 'arraybuffer' );
		loader.setRequestHeader( this.requestHeader );
		loader.setWithCredentials( this.withCredentials );
		loader.load( url, function ( data ) {
			try {
				scope.parse( data, resourcePath, function ( gltf ) {
					onLoad( gltf );
					scope.manager.itemEnd( url );
				}, _onError );
			} catch ( e ) {
				_onError( e );
			}
		}, onProgress, _onError );
	}
	setDRACOLoader( 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 json;
		const extensions = {};
		const plugins = {};
		const textDecoder = new TextDecoder();
		if ( typeof data === 'string' ) {
			json = JSON.parse( data );
		} else if ( data instanceof ArrayBuffer ) {
			const magic = textDecoder.decode( 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;
				}
				json = JSON.parse( extensions[ EXTENSIONS.KHR_BINARY_GLTF ].content );
			} else {
				json = JSON.parse( textDecoder.decode( data ) );
			}
		} else {
			json = data;
		}
		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 );
			if ( ! plugin.name ) console.error( 'THREE.GLTFLoader: Invalid plugin found: missing name' );
			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_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 );
	}
	parseAsync( data, path ) {
		const scope = this;
		return new Promise( function ( resolve, reject ) {
			scope.parse( data, path, resolve, reject );
		} );
	}
}
/* 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_SHEEN: 'KHR_materials_sheen',
	KHR_MATERIALS_SPECULAR: 'KHR_materials_specular',
	KHR_MATERIALS_TRANSMISSION: 'KHR_materials_transmission',
	KHR_MATERIALS_IRIDESCENCE: 'KHR_materials_iridescence',
	KHR_MATERIALS_ANISOTROPY: 'KHR_materials_anisotropy',
	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',
	KHR_MATERIALS_EMISSIVE_STRENGTH: 'KHR_materials_emissive_strength',
	EXT_MATERIALS_BUMP: 'EXT_materials_bump',
	EXT_TEXTURE_WEBP: 'EXT_texture_webp',
	EXT_TEXTURE_AVIF: 'EXT_texture_avif',
	EXT_MESHOPT_COMPRESSION: 'EXT_meshopt_compression',
	EXT_MESH_GPU_INSTANCING: 'EXT_mesh_gpu_instancing'
};
/**
 * 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;
		// 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 Color( 0xffffff );
		if ( lightDef.color !== undefined ) color.setRGB( lightDef.color[ 0 ], lightDef.color[ 1 ], lightDef.color[ 2 ], LinearSRGBColorSpace );
		const range = lightDef.range !== undefined ? lightDef.range : 0;
		switch ( lightDef.type ) {
			case 'directional':
				lightNode = new DirectionalLight( color );
				lightNode.target.position.set( 0, 0, - 1 );
				lightNode.add( lightNode.target );
				break;
			case 'point':
				lightNode = new PointLight( color );
				lightNode.distance = range;
				break;
			case 'spot':
				lightNode = new SpotLight( color );
				lightNode.distance = range;
				// Handle spotlight properties.
				lightDef.spot = lightDef.spot || {};
				lightDef.spot.innerConeAngle = lightDef.spot.innerConeAngle !== undefined ? lightDef.spot.innerConeAngle : 0;
				lightDef.spot.outerConeAngle = lightDef.spot.outerConeAngle !== undefined ? lightDef.spot.outerConeAngle : Math.PI / 4.0;
				lightNode.angle = lightDef.spot.outerConeAngle;
				lightNode.penumbra = 1.0 - lightDef.spot.innerConeAngle / lightDef.spot.outerConeAngle;
				lightNode.target.position.set( 0, 0, - 1 );
				lightNode.add( lightNode.target );
				break;
			default:
				throw new Error( 'THREE.GLTFLoader: Unexpected light type: ' + lightDef.type );
		}
		// Some lights (e.g. spot) default to a position other than the origin. Reset the position
		// here, because node-level parsing will only override position if explicitly specified.
		lightNode.position.set( 0, 0, 0 );
		lightNode.decay = 2;
		assignExtrasToUserData( lightNode, lightDef );
		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;
	}
	getDependency( type, index ) {
		if ( type !== 'light' ) return;
		return this._loadLight( index );
	}
	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 MeshBasicMaterial;
	}
	extendParams( materialParams, materialDef, parser ) {
		const pending = [];
		materialParams.color = new 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.setRGB( array[ 0 ], array[ 1 ], array[ 2 ], LinearSRGBColorSpace );
				materialParams.opacity = array[ 3 ];
			}
			if ( metallicRoughness.baseColorTexture !== undefined ) {
				pending.push( parser.assignTexture( materialParams, 'map', metallicRoughness.baseColorTexture, SRGBColorSpace ) );
			}
		}
		return Promise.all( pending );
	}
}
/**
 * Materials Emissive Strength Extension
 *
 * Specification: https://github.com/KhronosGroup/glTF/blob/5768b3ce0ef32bc39cdf1bef10b948586635ead3/extensions/2.0/Khronos/KHR_materials_emissive_strength/README.md
 */
class GLTFMaterialsEmissiveStrengthExtension {
	constructor( parser ) {
		this.parser = parser;
		this.name = EXTENSIONS.KHR_MATERIALS_EMISSIVE_STRENGTH;
	}
	extendMaterialParams( materialIndex, materialParams ) {
		const parser = this.parser;
		const materialDef = parser.json.materials[ materialIndex ];
		if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) {
			return Promise.resolve();
		}
		const emissiveStrength = materialDef.extensions[ this.name ].emissiveStrength;
		if ( emissiveStrength !== undefined ) {
			materialParams.emissiveIntensity = emissiveStrength;
		}
		return Promise.resolve();
	}
}
/**
 * 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 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;
				materialParams.clearcoatNormalScale = new Vector2( scale, scale );
			}
		}
		return Promise.all( pending );
	}
}
/**
 * Iridescence Materials Extension
 *
 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_materials_iridescence
 */
class GLTFMaterialsIridescenceExtension {
	constructor( parser ) {
		this.parser = parser;
		this.name = EXTENSIONS.KHR_MATERIALS_IRIDESCENCE;
	}
	getMaterialType( materialIndex ) {
		const parser = this.parser;
		const materialDef = parser.json.materials[ materialIndex ];
		if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) return null;
		return 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.iridescenceFactor !== undefined ) {
			materialParams.iridescence = extension.iridescenceFactor;
		}
		if ( extension.iridescenceTexture !== undefined ) {
			pending.push( parser.assignTexture( materialParams, 'iridescenceMap', extension.iridescenceTexture ) );
		}
		if ( extension.iridescenceIor !== undefined ) {
			materialParams.iridescenceIOR = extension.iridescenceIor;
		}
		if ( materialParams.iridescenceThicknessRange === undefined ) {
			materialParams.iridescenceThicknessRange = [ 100, 400 ];
		}
		if ( extension.iridescenceThicknessMinimum !== undefined ) {
			materialParams.iridescenceThicknessRange[ 0 ] = extension.iridescenceThicknessMinimum;
		}
		if ( extension.iridescenceThicknessMaximum !== undefined ) {
			materialParams.iridescenceThicknessRange[ 1 ] = extension.iridescenceThicknessMaximum;
		}
		if ( extension.iridescenceThicknessTexture !== undefined ) {
			pending.push( parser.assignTexture( materialParams, 'iridescenceThicknessMap', extension.iridescenceThicknessTexture ) );
		}
		return Promise.all( pending );
	}
}
/**
 * Sheen Materials Extension
 *
 * Specification: https://github.com/KhronosGroup/glTF/tree/main/extensions/2.0/Khronos/KHR_materials_sheen
 */
class GLTFMaterialsSheenExtension {
	constructor( parser ) {
		this.parser = parser;
		this.name = EXTENSIONS.KHR_MATERIALS_SHEEN;
	}
	getMaterialType( materialIndex ) {
		const parser = this.parser;
		const materialDef = parser.json.materials[ materialIndex ];
		if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) return null;
		return 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 = [];
		materialParams.sheenColor = new Color( 0, 0, 0 );
		materialParams.sheenRoughness = 0;
		materialParams.sheen = 1;
		const extension = materialDef.extensions[ this.name ];
		if ( extension.sheenColorFactor !== undefined ) {
			const colorFactor = extension.sheenColorFactor;
			materialParams.sheenColor.setRGB( colorFactor[ 0 ], colorFactor[ 1 ], colorFactor[ 2 ], LinearSRGBColorSpace );
		}
		if ( extension.sheenRoughnessFactor !== undefined ) {
			materialParams.sheenRoughness = extension.sheenRoughnessFactor;
		}
		if ( extension.sheenColorTexture !== undefined ) {
			pending.push( parser.assignTexture( materialParams, 'sheenColorMap', extension.sheenColorTexture, SRGBColorSpace ) );
		}
		if ( extension.sheenRoughnessTexture !== undefined ) {
			pending.push( parser.assignTexture( materialParams, 'sheenRoughnessMap', extension.sheenRoughnessTexture ) );
		}
		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 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 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 || Infinity;
		const colorArray = extension.attenuationColor || [ 1, 1, 1 ];
		materialParams.attenuationColor = new Color().setRGB( colorArray[ 0 ], colorArray[ 1 ], colorArray[ 2 ], LinearSRGBColorSpace );
		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 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 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.specularColor = new Color().setRGB( colorArray[ 0 ], colorArray[ 1 ], colorArray[ 2 ], LinearSRGBColorSpace );
		if ( extension.specularColorTexture !== undefined ) {
			pending.push( parser.assignTexture( materialParams, 'specularColorMap', extension.specularColorTexture, SRGBColorSpace ) );
		}
		return Promise.all( pending );
	}
}
/**
 * Materials bump Extension
 *
 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/EXT_materials_bump
 */
class GLTFMaterialsBumpExtension {
	constructor( parser ) {
		this.parser = parser;
		this.name = EXTENSIONS.EXT_MATERIALS_BUMP;
	}
	getMaterialType( materialIndex ) {
		const parser = this.parser;
		const materialDef = parser.json.materials[ materialIndex ];
		if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) return null;
		return 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.bumpScale = extension.bumpFactor !== undefined ? extension.bumpFactor : 1.0;
		if ( extension.bumpTexture !== undefined ) {
			pending.push( parser.assignTexture( materialParams, 'bumpMap', extension.bumpTexture ) );
		}
		return Promise.all( pending );
	}
}
/**
 * Materials anisotropy Extension
 *
 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_materials_anisotropy
 */
class GLTFMaterialsAnisotropyExtension {
	constructor( parser ) {
		this.parser = parser;
		this.name = EXTENSIONS.KHR_MATERIALS_ANISOTROPY;
	}
	getMaterialType( materialIndex ) {
		const parser = this.parser;
		const materialDef = parser.json.materials[ materialIndex ];
		if ( ! materialDef.extensions || ! materialDef.extensions[ this.name ] ) return null;
		return 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.anisotropyStrength !== undefined ) {
			materialParams.anisotropy = extension.anisotropyStrength;
		}
		if ( extension.anisotropyRotation !== undefined ) {
			materialParams.anisotropyRotation = extension.anisotropyRotation;
		}
		if ( extension.anisotropyTexture !== undefined ) {
			pending.push( parser.assignTexture( materialParams, 'anisotropyMap', extension.anisotropyTexture ) );
		}
		return Promise.all( pending );
	}
}
/**
 * BasisU 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 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, extension.source, loader );
	}
}
/**
 * WebP 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, extension.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;
	}
}
/**
 * AVIF Texture Extension
 *
 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Vendor/EXT_texture_avif
 */
class GLTFTextureAVIFExtension {
	constructor( parser ) {
		this.parser = parser;
		this.name = EXTENSIONS.EXT_TEXTURE_AVIF;
		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, extension.source, loader );
			if ( json.extensionsRequired && json.extensionsRequired.indexOf( name ) >= 0 ) {
				throw new Error( 'THREE.GLTFLoader: AVIF 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.
				image.src = 'data:image/avif;base64,AAAAIGZ0eXBhdmlmAAAAAGF2aWZtaWYxbWlhZk1BMUIAAADybWV0YQAAAAAAAAAoaGRscgAAAAAAAAAAcGljdAAAAAAAAAAAAAAAAGxpYmF2aWYAAAAADnBpdG0AAAAAAAEAAAAeaWxvYwAAAABEAAABAAEAAAABAAABGgAAABcAAAAoaWluZgAAAAAAAQAAABppbmZlAgAAAAABAABhdjAxQ29sb3IAAAAAamlwcnAAAABLaXBjbwAAABRpc3BlAAAAAAAAAAEAAAABAAAAEHBpeGkAAAAAAwgICAAAAAxhdjFDgQAMAAAAABNjb2xybmNseAACAAIABoAAAAAXaXBtYQAAAAAAAAABAAEEAQKDBAAAAB9tZGF0EgAKCBgABogQEDQgMgkQAAAAB8dSLfI=';
				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 buffer.then( function ( res ) {
				const byteOffset = extensionDef.byteOffset || 0;
				const byteLength = extensionDef.byteLength || 0;
				const count = extensionDef.count;
				const stride = extensionDef.byteStride;
				const source = new Uint8Array( res, byteOffset, byteLength );
				if ( decoder.decodeGltfBufferAsync ) {
					return decoder.decodeGltfBufferAsync( count, stride, source, extensionDef.mode, extensionDef.filter ).then( function ( res ) {
						return res.buffer;
					} );
				} else {
					// Support for MeshoptDecoder 0.18 or earlier, without decodeGltfBufferAsync
					return decoder.ready.then( function () {
						const result = new ArrayBuffer( count * stride );
						decoder.decodeGltfBuffer( new Uint8Array( result ), count, stride, source, extensionDef.mode, extensionDef.filter );
						return result;
					} );
				}
			} );
		} else {
			return null;
		}
	}
}
/**
 * GPU Instancing Extension
 *
 * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Vendor/EXT_mesh_gpu_instancing
 *
 */
class GLTFMeshGpuInstancing {
	constructor( parser ) {
		this.name = EXTENSIONS.EXT_MESH_GPU_INSTANCING;
		this.parser = parser;
	}
	createNodeMesh( nodeIndex ) {
		const json = this.parser.json;
		const nodeDef = json.nodes[ nodeIndex ];
		if ( ! nodeDef.extensions || ! nodeDef.extensions[ this.name ] ||
			nodeDef.mesh === undefined ) {
			return null;
		}
		const meshDef = json.meshes[ nodeDef.mesh ];
		// No Points or Lines + Instancing support yet
		for ( const primitive of meshDef.primitives ) {
			if ( primitive.mode !== WEBGL_CONSTANTS.TRIANGLES &&
				 primitive.mode !== WEBGL_CONSTANTS.TRIANGLE_STRIP &&
				 primitive.mode !== WEBGL_CONSTANTS.TRIANGLE_FAN &&
				 primitive.mode !== undefined ) {
				return null;
			}
		}
		const extensionDef = nodeDef.extensions[ this.name ];
		const attributesDef = extensionDef.attributes;
		// @TODO: Can we support InstancedMesh + SkinnedMesh?
		const pending = [];
		const attributes = {};
		for ( const key in attributesDef ) {
			pending.push( this.parser.getDependency( 'accessor', attributesDef[ key ] ).then( accessor => {
				attributes[ key ] = accessor;
				return attributes[ key ];
			} ) );
		}
		if ( pending.length < 1 ) {
			return null;
		}
		pending.push( this.parser.createNodeMesh( nodeIndex ) );
		return Promise.all( pending ).then( results => {
			const nodeObject = results.pop();
			const meshes = nodeObject.isGroup ? nodeObject.children : [ nodeObject ];
			const count = results[ 0 ].count; // All attribute counts should be same
			const instancedMeshes = [];
			for ( const mesh of meshes ) {
				// Temporal variables
				const m = new Matrix4();
				const p = new Vector3();
				const q = new Quaternion();
				const s = new Vector3( 1, 1, 1 );
				const instancedMesh = new InstancedMesh( mesh.geometry, mesh.material, count );
				for ( let i = 0; i < count; i ++ ) {
					if ( attributes.TRANSLATION ) {
						p.fromBufferAttribute( attributes.TRANSLATION, i );
					}
					if ( attributes.ROTATION ) {
						q.fromBufferAttribute( attributes.ROTATION, i );
					}
					if ( attributes.SCALE ) {
						s.fromBufferAttribute( attributes.SCALE, i );
					}
					instancedMesh.setMatrixAt( i, m.compose( p, q, s ) );
				}
				// Add instance attributes to the geometry, excluding TRS.
				for ( const attributeName in attributes ) {
					if ( attributeName === '_COLOR_0' ) {
						const attr = attributes[ attributeName ];
						instancedMesh.instanceColor = new InstancedBufferAttribute( attr.array, attr.itemSize, attr.normalized );
					} else if ( attributeName !== 'TRANSLATION' &&
						 attributeName !== 'ROTATION' &&
						 attributeName !== 'SCALE' ) {
						mesh.geometry.setAttribute( attributeName, attributes[ attributeName ] );
					}
				}
				// Just in case
				Object3D.prototype.copy.call( instancedMesh, mesh );
				this.parser.assignFinalMaterial( instancedMesh );
				instancedMeshes.push( instancedMesh );
			}
			if ( nodeObject.isGroup ) {
				nodeObject.clear();
				nodeObject.add( ... instancedMeshes );
				return nodeObject;
			}
			return instancedMeshes[ 0 ];
		} );
	}
}
/* 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 );
		const textDecoder = new TextDecoder();
		this.header = {
			magic: textDecoder.decode( 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 = textDecoder.decode( 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 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.name;
				attributeNormalizedMap[ threeAttributeName ] = accessorDef.normalized === true;
			}
		}
		return parser.getDependency( 'bufferView', bufferViewIndex ).then( function ( bufferView ) {
			return new Promise( function ( resolve, reject ) {
				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, LinearSRGBColorSpace, reject );
			} );
		} );
	}
}
/**
 * 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 || transform.texCoord === texture.channel )
			&& 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.texCoord !== undefined ) {
			texture.channel = transform.texCoord;
		}
		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;
	}
}
/**
 * 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 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;
	}
	interpolate_( 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 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: NearestFilter,
	9729: LinearFilter,
	9984: NearestMipmapNearestFilter,
	9985: LinearMipmapNearestFilter,
	9986: NearestMipmapLinearFilter,
	9987: LinearMipmapLinearFilter
};
const WEBGL_WRAPPINGS = {
	33071: ClampToEdgeWrapping,
	33648: MirroredRepeatWrapping,
	10497: 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: 'uv1',
	TEXCOORD_2: 'uv2',
	TEXCOORD_3: 'uv3',
	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: InterpolateLinear,
	STEP: InterpolateDiscrete
};
const ALPHA_MODES = {
	OPAQUE: 'OPAQUE',
	MASK: 'MASK',
	BLEND: 'BLEND'
};
/**
 * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#default-material
 */
function createDefaultMaterial( cache ) {
	if ( cache[ 'DefaultMaterial' ] === undefined ) {
		cache[ 'DefaultMaterial' ] = new MeshStandardMaterial( {
			color: 0xFFFFFF,
			emissive: 0x000000,
			metalness: 1,
			roughness: 1,
			transparent: false,
			depthTest: true,
			side: FrontSide
		} );
	}
	return cache[ 'DefaultMaterial' ];
}
function addUnknownExtensionsToUserData( knownExtensions, object, objectDef ) {
	// Add unknown glTF extensions to an object's userData.
	for ( 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;
	let hasMorphColor = 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 ( target.COLOR_0 !== undefined ) hasMorphColor = true;
		if ( hasMorphPosition && hasMorphNormal && hasMorphColor ) break;
	}
	if ( ! hasMorphPosition && ! hasMorphNormal && ! hasMorphColor ) return Promise.resolve( geometry );
	const pendingPositionAccessors = [];
	const pendingNormalAccessors = [];
	const pendingColorAccessors = [];
	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 );
		}
		if ( hasMorphColor ) {
			const pendingAccessor = target.COLOR_0 !== undefined
				? parser.getDependency( 'accessor', target.COLOR_0 )
				: geometry.attributes.color;
			pendingColorAccessors.push( pendingAccessor );
		}
	}
	return Promise.all( [
		Promise.all( pendingPositionAccessors ),
		Promise.all( pendingNormalAccessors ),
		Promise.all( pendingColorAccessors )
	] ).then( function ( accessors ) {
		const morphPositions = accessors[ 0 ];
		const morphNormals = accessors[ 1 ];
		const morphColors = accessors[ 2 ];
		if ( hasMorphPosition ) geometry.morphAttributes.position = morphPositions;
		if ( hasMorphNormal ) geometry.morphAttributes.normal = morphNormals;
		if ( hasMorphColor ) geometry.morphAttributes.color = morphColors;
		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 ) {
	let geometryKey;
	const dracoExtension = primitiveDef.extensions && primitiveDef.extensions[ EXTENSIONS.KHR_DRACO_MESH_COMPRESSION ];
	if ( dracoExtension ) {
		geometryKey = 'draco:' + dracoExtension.bufferView
				+ ':' + dracoExtension.indices
				+ ':' + createAttributesKey( dracoExtension.attributes );
	} else {
		geometryKey = primitiveDef.indices + ':' + createAttributesKey( primitiveDef.attributes ) + ':' + primitiveDef.mode;
	}
	if ( primitiveDef.targets !== undefined ) {
		for ( let i = 0, il = primitiveDef.targets.length; i < il; i ++ ) {
			geometryKey += ':' + createAttributesKey( primitiveDef.targets[ i ] );
		}
	}
	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.' );
	}
}
function getImageURIMimeType( uri ) {
	if ( uri.search( /\.jpe?g($|\?)/i ) > 0 || uri.search( /^data\:image\/jpeg/ ) === 0 ) return 'image/jpeg';
	if ( uri.search( /\.webp($|\?)/i ) > 0 || uri.search( /^data\:image\/webp/ ) === 0 ) return 'image/webp';
	return 'image/png';
}
const _identityMatrix = new Matrix4();
/* 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();
		// BufferGeometry caching
		this.primitiveCache = {};
		// Node cache
		this.nodeCache = {};
		// Object3D instance caches
		this.meshCache = { refs: {}, uses: {} };
		this.cameraCache = { refs: {}, uses: {} };
		this.lightCache = { refs: {}, uses: {} };
		this.sourceCache = {};
		this.textureCache = {};
		// Track node names, to ensure no duplicates
		this.nodeNamesUsed = {};
		// Use an ImageBitmapLoader if imageBitmaps are supported. Moves much of the
		// expensive work of uploading a texture to the GPU off the main thread.
		let isSafari = false;
		let isFirefox = false;
		let firefoxVersion = - 1;
		if ( typeof navigator !== 'undefined' ) {
			isSafari = /^((?!chrome|android).)*safari/i.test( navigator.userAgent ) === true;
			isFirefox = navigator.userAgent.indexOf( 'Firefox' ) > - 1;
			firefoxVersion = isFirefox ? navigator.userAgent.match( /Firefox\/([0-9]+)\./ )[ 1 ] : - 1;
		}
		if ( typeof createImageBitmap === 'undefined' || isSafari || ( isFirefox && firefoxVersion < 98 ) ) {
			this.textureLoader = new TextureLoader( this.options.manager );
		} else {
			this.textureLoader = new ImageBitmapLoader( this.options.manager );
		}
		this.textureLoader.setCrossOrigin( this.options.crossOrigin );
		this.textureLoader.setRequestHeader( this.options.requestHeader );
		this.fileLoader = new 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();
		this.nodeCache = {};
		// 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 );
			return 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 Bone or an
		// 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 SkinnedMesh or Mesh. Use the node's mesh reference
				// to mark SkinnedMesh if node has skin.
				if ( nodeDef.skin !== undefined ) {
					meshDefs[ nodeDef.mesh ].isSkinnedMesh = true;
				}
			}
			if ( nodeDef.camera !== undefined ) {
				this._addNodeRef( this.cameraCache, nodeDef.camera );
			}
		}
	}
	/**
	 * Counts references to shared node / Object3D resources. These resources
	 * can be reused, or "instantiated", at multiple nodes in the scene
	 * hierarchy. Mesh, Camera, and Light instances are instantiated and must
	 * be marked. Non-scenegraph resources (like Materials, Geometries, and
	 * Textures) can be reused directly and are not marked here.
	 *
	 * Example: CesiumMilkTruck sample model reuses "Wheel" meshes.
	 */
	_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();
		// Propagates mappings to the cloned object, prevents mappings on the
		// original object from being lost.
		const updateMappings = ( original, clone ) => {
			const mappings = this.associations.get( original );
			if ( mappings != null ) {
				this.associations.set( clone, mappings );
			}
			for ( const [ i, child ] of original.children.entries() ) {
				updateMappings( child, clone.children[ i ] );
			}
		};
		updateMappings( object, ref );
		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._invokeOne( function ( ext ) {
						return ext.loadNode && ext.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._invokeOne( function ( ext ) {
						return ext.loadAnimation && ext.loadAnimation( index );
					} );
					break;
				case 'camera':
					dependency = this.loadCamera( index );
					break;
				default:
					dependency = this._invokeOne( function ( ext ) {
						return ext != this && ext.getDependency && ext.getDependency( type, index );
					} );
					if ( ! dependency ) {
						throw new Error( 'Unknown type: ' + type );
					}
					break;
			}
			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( LoaderUtils.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 ) {
			const itemSize = WEBGL_TYPE_SIZES[ accessorDef.type ];
			const TypedArray = WEBGL_COMPONENT_TYPES[ accessorDef.componentType ];
			const normalized = accessorDef.normalized === true;
			const array = new TypedArray( accessorDef.count * itemSize );
			return Promise.resolve( new BufferAttribute( array, itemSize, normalized ) );
		}
		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 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 InterleavedBuffer( array, byteStride / elementBytes );
					parser.cache.add( ibCacheKey, ib );
				}
				bufferAttribute = new InterleavedBufferAttribute( ib, itemSize, ( byteOffset % byteStride ) / elementBytes, normalized );
			} else {
				if ( bufferView === null ) {
					array = new TypedArray( accessorDef.count * itemSize );
				} else {
					array = new TypedArray( bufferView, byteOffset, accessorDef.count * itemSize );
				}
				bufferAttribute = new BufferAttribute( array, itemSize, normalized );
			}
			// https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#sparse-accessors
			if ( accessorDef.sparse !== undefined ) {
				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 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 BufferAttribute.' );
				}
			}
			return bufferAttribute;
		} );
	}
	/**
	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#textures
	 * @param {number} textureIndex
	 * @return {Promise<THREE.Texture|null>}
	 */
	loadTexture( textureIndex ) {
		const json = this.json;
		const options = this.options;
		const textureDef = json.textures[ textureIndex ];
		const sourceIndex = textureDef.source;
		const sourceDef = json.images[ sourceIndex ];
		let loader = this.textureLoader;
		if ( sourceDef.uri ) {
			const handler = options.manager.getHandler( sourceDef.uri );
			if ( handler !== null ) loader = handler;
		}
		return this.loadTextureImage( textureIndex, sourceIndex, loader );
	}
	loadTextureImage( textureIndex, sourceIndex, loader ) {
		const parser = this;
		const json = this.json;
		const textureDef = json.textures[ textureIndex ];
		const sourceDef = json.images[ sourceIndex ];
		const cacheKey = ( sourceDef.uri || sourceDef.bufferView ) + ':' + textureDef.sampler;
		if ( this.textureCache[ cacheKey ] ) {
			// See https://github.com/mrdoob/three.js/issues/21559.
			return this.textureCache[ cacheKey ];
		}
		const promise = this.loadImageSource( sourceIndex, loader ).then( function ( texture ) {
			texture.flipY = false;
			texture.name = textureDef.name || sourceDef.name || '';
			if ( texture.name === '' && typeof sourceDef.uri === 'string' && sourceDef.uri.startsWith( 'data:image/' ) === false ) {
				texture.name = sourceDef.uri;
			}
			const samplers = json.samplers || {};
			const sampler = samplers[ textureDef.sampler ] || {};
			texture.magFilter = WEBGL_FILTERS[ sampler.magFilter ] || LinearFilter;
			texture.minFilter = WEBGL_FILTERS[ sampler.minFilter ] || LinearMipmapLinearFilter;
			texture.wrapS = WEBGL_WRAPPINGS[ sampler.wrapS ] || RepeatWrapping;
			texture.wrapT = WEBGL_WRAPPINGS[ sampler.wrapT ] || RepeatWrapping;
			parser.associations.set( texture, { textures: textureIndex } );
			return texture;
		} ).catch( function () {
			return null;
		} );
		this.textureCache[ cacheKey ] = promise;
		return promise;
	}
	loadImageSource( sourceIndex, loader ) {
		const parser = this;
		const json = this.json;
		const options = this.options;
		if ( this.sourceCache[ sourceIndex ] !== undefined ) {
			return this.sourceCache[ sourceIndex ].then( ( texture ) => texture.clone() );
		}
		const sourceDef = json.images[ sourceIndex ];
		const URL = self.URL || self.webkitURL;
		let sourceURI = sourceDef.uri || '';
		let isObjectURL = false;
		if ( sourceDef.bufferView !== undefined ) {
			// Load binary image data from bufferView, if provided.
			sourceURI = parser.getDependency( 'bufferView', sourceDef.bufferView ).then( function ( bufferView ) {
				isObjectURL = true;
				const blob = new Blob( [ bufferView ], { type: sourceDef.mimeType } );
				sourceURI = URL.createObjectURL( blob );
				return sourceURI;
			} );
		} else if ( sourceDef.uri === undefined ) {
			throw new Error( 'THREE.GLTFLoader: Image ' + sourceIndex + ' 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 Texture( imageBitmap );
						texture.needsUpdate = true;
						resolve( texture );
					};
				}
				loader.load( LoaderUtils.resolveURL( sourceURI, options.path ), onLoad, undefined, reject );
			} );
		} ).then( function ( texture ) {
			// Clean up resources and configure Texture.
			if ( isObjectURL === true ) {
				URL.revokeObjectURL( sourceURI );
			}
			texture.userData.mimeType = sourceDef.mimeType || getImageURIMimeType( sourceDef.uri );
			return texture;
		} ).catch( function ( error ) {
			console.error( 'THREE.GLTFLoader: Couldn\'t load texture', sourceURI );
			throw error;
		} );
		this.sourceCache[ sourceIndex ] = 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, colorSpace ) {
		const parser = this;
		return this.getDependency( 'texture', mapDef.index ).then( function ( texture ) {
			if ( ! texture ) return null;
			if ( mapDef.texCoord !== undefined && mapDef.texCoord > 0 ) {
				texture = texture.clone();
				texture.channel = mapDef.texCoord;
			}
			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 );
				}
			}
			if ( colorSpace !== undefined ) {
				texture.colorSpace = colorSpace;
			}
			materialParams[ mapName ] = texture;
			return texture;
		} );
	}
	/**
	 * Assigns final material to a Mesh, Line, or Points instance. The instance
	 * already has a material (generated from the glTF material options alone)
	 * but reuse of the same glTF material may require multiple threejs materials
	 * to accommodate different primitive types, defines, etc. New materials will
	 * be created if necessary, and reused from a cache.
	 * @param  {Object3D} mesh Mesh, Line, or Points instance.
	 */
	assignFinalMaterial( mesh ) {
		const geometry = mesh.geometry;
		let material = mesh.material;
		const useDerivativeTangents = 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 PointsMaterial();
				Material.prototype.copy.call( pointsMaterial, material );
				pointsMaterial.color.copy( material.color );
				pointsMaterial.map = material.map;
				pointsMaterial.sizeAttenuation = false; // glTF spec says points should be 1px
				this.cache.add( cacheKey, pointsMaterial );
			}
			material = pointsMaterial;
		} else if ( mesh.isLine ) {
			const cacheKey = 'LineBasicMaterial:' + material.uuid;
			let lineMaterial = this.cache.get( cacheKey );
			if ( ! lineMaterial ) {
				lineMaterial = new LineBasicMaterial();
				Material.prototype.copy.call( lineMaterial, material );
				lineMaterial.color.copy( material.color );
				lineMaterial.map = material.map;
				this.cache.add( cacheKey, lineMaterial );
			}
			material = lineMaterial;
		}
		// Clone the material if it will be modified
		if ( useDerivativeTangents || useVertexColors || useFlatShading ) {
			let cacheKey = 'ClonedMaterial:' + material.uuid + ':';
			if ( useDerivativeTangents ) cacheKey += 'derivative-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 ( useDerivativeTangents ) {
					// 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;
		}
		mesh.material = material;
	}
	getMaterialType( /* materialIndex */ ) {
		return 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_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 Color( 1.0, 1.0, 1.0 );
			materialParams.opacity = 1.0;
			if ( Array.isArray( metallicRoughness.baseColorFactor ) ) {
				const array = metallicRoughness.baseColorFactor;
				materialParams.color.setRGB( array[ 0 ], array[ 1 ], array[ 2 ], LinearSRGBColorSpace );
				materialParams.opacity = array[ 3 ];
			}
			if ( metallicRoughness.baseColorTexture !== undefined ) {
				pending.push( parser.assignTexture( materialParams, 'map', metallicRoughness.baseColorTexture, SRGBColorSpace ) );
			}
			materialParams.metalness = metallicRoughness.metallicFactor !== undefined ? metallicRoughness.metallicFactor : 1.0;
			materialParams.roughness = metallicRoughness.roughnessFactor !== undefined ? metallicRoughness.roughnessFactor : 1.0;
			if ( metallicRoughness.metallicRoughnessTexture !== undefined ) {
				pending.push( parser.assignTexture( materialParams, 'metalnessMap', metallicRoughness.metallicRoughnessTexture ) );
				pending.push( parser.assignTexture( materialParams, 'roughnessMap', metallicRoughness.metallicRoughnessTexture ) );
			}
			materialType = this._invokeOne( function ( ext ) {
				return ext.getMaterialType && ext.getMaterialType( materialIndex );
			} );
			pending.push( Promise.all( this._invokeAll( function ( ext ) {
				return ext.extendMaterialParams && ext.extendMaterialParams( materialIndex, materialParams );
			} ) ) );
		}
		if ( materialDef.doubleSided === true ) {
			materialParams.side = DoubleSide;
		}
		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.transparent = false;
			if ( alphaMode === ALPHA_MODES.MASK ) {
				materialParams.alphaTest = materialDef.alphaCutoff !== undefined ? materialDef.alphaCutoff : 0.5;
			}
		}
		if ( materialDef.normalTexture !== undefined && materialType !== MeshBasicMaterial ) {
			pending.push( parser.assignTexture( materialParams, 'normalMap', materialDef.normalTexture ) );
			materialParams.normalScale = new Vector2( 1, 1 );
			if ( materialDef.normalTexture.scale !== undefined ) {
				const scale = materialDef.normalTexture.scale;
				materialParams.normalScale.set( scale, scale );
			}
		}
		if ( materialDef.occlusionTexture !== undefined && materialType !== MeshBasicMaterial ) {
			pending.push( parser.assignTexture( materialParams, 'aoMap', materialDef.occlusionTexture ) );
			if ( materialDef.occlusionTexture.strength !== undefined ) {
				materialParams.aoMapIntensity = materialDef.occlusionTexture.strength;
			}
		}
		if ( materialDef.emissiveFactor !== undefined && materialType !== MeshBasicMaterial ) {
			const emissiveFactor = materialDef.emissiveFactor;
			materialParams.emissive = new Color().setRGB( emissiveFactor[ 0 ], emissiveFactor[ 1 ], emissiveFactor[ 2 ], LinearSRGBColorSpace );
		}
		if ( materialDef.emissiveTexture !== undefined && materialType !== MeshBasicMaterial ) {
			pending.push( parser.assignTexture( materialParams, 'emissiveMap', materialDef.emissiveTexture, SRGBColorSpace ) );
		}
		return Promise.all( pending ).then( function () {
			const material = new materialType( materialParams );
			if ( materialDef.name ) material.name = materialDef.name;
			assignExtrasToUserData( material, materialDef );
			parser.associations.set( material, { materials: materialIndex } );
			if ( materialDef.extensions ) addUnknownExtensionsToUserData( extensions, material, materialDef );
			return material;
		} );
	}
	/** When Object3D instances are targeted by animation, they need unique names. */
	createUniqueName( originalName ) {
		const sanitizedName = PropertyBinding.sanitizeNodeName( originalName || '' );
		if ( sanitizedName in this.nodeNamesUsed ) {
			return sanitizedName + '_' + ( ++ this.nodeNamesUsed[ sanitizedName ] );
		} else {
			this.nodeNamesUsed[ sanitizedName ] = 0;
			return sanitizedName;
		}
	}
	/**
	 * 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 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 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 SkinnedMesh( geometry, material )
						: new Mesh( geometry, material );
					if ( mesh.isSkinnedMesh === true ) {
						// normalize skin weights to fix malformed assets (see #15319)
						mesh.normalizeSkinWeights();
					}
					if ( primitive.mode === WEBGL_CONSTANTS.TRIANGLE_STRIP ) {
						mesh.geometry = toTrianglesDrawMode( mesh.geometry, TriangleStripDrawMode );
					} else if ( primitive.mode === WEBGL_CONSTANTS.TRIANGLE_FAN ) {
						mesh.geometry = toTrianglesDrawMode( mesh.geometry, TriangleFanDrawMode );
					}
				} else if ( primitive.mode === WEBGL_CONSTANTS.LINES ) {
					mesh = new LineSegments( geometry, material );
				} else if ( primitive.mode === WEBGL_CONSTANTS.LINE_STRIP ) {
					mesh = new Line( geometry, material );
				} else if ( primitive.mode === WEBGL_CONSTANTS.LINE_LOOP ) {
					mesh = new LineLoop( geometry, material );
				} else if ( primitive.mode === WEBGL_CONSTANTS.POINTS ) {
					mesh = new Points( geometry, material );
				} else {
					throw new Error( 'THREE.GLTFLoader: Primitive mode unsupported: ' + primitive.mode );
				}
				if ( Object.keys( mesh.geometry.morphAttributes ).length > 0 ) {
					updateMorphTargets( mesh, meshDef );
				}
				mesh.name = parser.createUniqueName( meshDef.name || ( 'mesh_' + meshIndex ) );
				assignExtrasToUserData( mesh, meshDef );
				if ( primitive.extensions ) addUnknownExtensionsToUserData( extensions, mesh, primitive );
				parser.assignFinalMaterial( mesh );
				meshes.push( mesh );
			}
			for ( let i = 0, il = meshes.length; i < il; i ++ ) {
				parser.associations.set( meshes[ i ], {
					meshes: meshIndex,
					primitives: i
				} );
			}
			if ( meshes.length === 1 ) {
				if ( meshDef.extensions ) addUnknownExtensionsToUserData( extensions, meshes[ 0 ], meshDef );
				return meshes[ 0 ];
			}
			const group = new Group();
			if ( meshDef.extensions ) addUnknownExtensionsToUserData( extensions, group, meshDef );
			parser.associations.set( group, { meshes: meshIndex } );
			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 PerspectiveCamera( MathUtils.radToDeg( params.yfov ), params.aspectRatio || 1, params.znear || 1, params.zfar || 2e6 );
		} else if ( cameraDef.type === 'orthographic' ) {
			camera = new OrthographicCamera( - params.xmag, params.xmag, params.ymag, - params.ymag, params.znear, params.zfar );
		}
		if ( cameraDef.name ) camera.name = this.createUniqueName( cameraDef.name );
		assignExtrasToUserData( camera, cameraDef );
		return Promise.resolve( camera );
	}
	/**
	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#skins
	 * @param {number} skinIndex
	 * @return {Promise<Skeleton>}
	 */
	loadSkin( skinIndex ) {
		const skinDef = this.json.skins[ skinIndex ];
		const pending = [];
		for ( let i = 0, il = skinDef.joints.length; i < il; i ++ ) {
			pending.push( this._loadNodeShallow( skinDef.joints[ i ] ) );
		}
		if ( skinDef.inverseBindMatrices !== undefined ) {
			pending.push( this.getDependency( 'accessor', skinDef.inverseBindMatrices ) );
		} else {
			pending.push( null );
		}
		return Promise.all( pending ).then( function ( results ) {
			const inverseBindMatrices = results.pop();
			const jointNodes = results;
			// Note that bones (joint nodes) may or may not be in the
			// scene graph at this time.
			const bones = [];
			const boneInverses = [];
			for ( let i = 0, il = jointNodes.length; i < il; i ++ ) {
				const jointNode = jointNodes[ i ];
				if ( jointNode ) {
					bones.push( jointNode );
					const mat = new Matrix4();
					if ( inverseBindMatrices !== null ) {
						mat.fromArray( inverseBindMatrices.array, i * 16 );
					}
					boneInverses.push( mat );
				} else {
					console.warn( 'THREE.GLTFLoader: Joint "%s" could not be found.', skinDef.joints[ i ] );
				}
			}
			return new Skeleton( bones, boneInverses );
		} );
	}
	/**
	 * 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 parser = this;
		const animationDef = json.animations[ animationIndex ];
		const animationName = animationDef.name ? animationDef.name : 'animation_' + 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;
			const input = animationDef.parameters !== undefined ? animationDef.parameters[ sampler.input ] : sampler.input;
			const output = animationDef.parameters !== undefined ? animationDef.parameters[ sampler.output ] : sampler.output;
			if ( target.node === undefined ) continue;
			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;
				if ( node.updateMatrix ) {
					node.updateMatrix();
				}
				const createdTracks = parser._createAnimationTracks( node, inputAccessor, outputAccessor, sampler, target );
				if ( createdTracks ) {
					for ( let k = 0; k < createdTracks.length; k ++ ) {
						tracks.push( createdTracks[ k ] );
					}
				}
			}
			return new AnimationClip( animationName, 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 parser = this;
		const nodeDef = json.nodes[ nodeIndex ];
		const nodePending = parser._loadNodeShallow( nodeIndex );
		const childPending = [];
		const childrenDef = nodeDef.children || [];
		for ( let i = 0, il = childrenDef.length; i < il; i ++ ) {
			childPending.push( parser.getDependency( 'node', childrenDef[ i ] ) );
		}
		const skeletonPending = nodeDef.skin === undefined
			? Promise.resolve( null )
			: parser.getDependency( 'skin', nodeDef.skin );
		return Promise.all( [
			nodePending,
			Promise.all( childPending ),
			skeletonPending
		] ).then( function ( results ) {
			const node = results[ 0 ];
			const children = results[ 1 ];
			const skeleton = results[ 2 ];
			if ( skeleton !== null ) {
				// This full traverse should be fine because
				// child glTF nodes have not been added to this node yet.
				node.traverse( function ( mesh ) {
					if ( ! mesh.isSkinnedMesh ) return;
					mesh.bind( skeleton, _identityMatrix );
				} );
			}
			for ( let i = 0, il = children.length; i < il; i ++ ) {
				node.add( children[ i ] );
			}
			return node;
		} );
	}
	// ._loadNodeShallow() parses a single node.
	// skin and child nodes are created and added in .loadNode() (no '_' prefix).
	_loadNodeShallow( nodeIndex ) {
		const json = this.json;
		const extensions = this.extensions;
		const parser = this;
		// This method is called from .loadNode() and .loadSkin().
		// Cache a node to avoid duplication.
		if ( this.nodeCache[ nodeIndex ] !== undefined ) {
			return this.nodeCache[ nodeIndex ];
		}
		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 ) : '';
		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 );
		} );
		this.nodeCache[ nodeIndex ] = Promise.all( pending ).then( function ( objects ) {
			let node;
			// .isBone isn't in glTF spec. See ._markDefs
			if ( nodeDef.isBone === true ) {
				node = new Bone();
			} else if ( objects.length > 1 ) {
				node = new Group();
			} else if ( objects.length === 1 ) {
				node = objects[ 0 ];
			} else {
				node = new Object3D();
			}
			if ( node !== objects[ 0 ] ) {
				for ( 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 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 );
				}
			}
			if ( ! parser.associations.has( node ) ) {
				parser.associations.set( node, {} );
			}
			parser.associations.get( node ).nodes = nodeIndex;
			return node;
		} );
		return this.nodeCache[ nodeIndex ];
	}
	/**
	 * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#scenes
	 * @param {number} sceneIndex
	 * @return {Promise<Group>}
	 */
	loadScene( sceneIndex ) {
		const extensions = this.extensions;
		const sceneDef = this.json.scenes[ sceneIndex ];
		const parser = this;
		// Loader returns Group, not Scene.
		// See: https://github.com/mrdoob/three.js/issues/18342#issuecomment-578981172
		const scene = new 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( parser.getDependency( 'node', nodeIds[ i ] ) );
		}
		return Promise.all( pending ).then( function ( nodes ) {
			for ( let i = 0, il = nodes.length; i < il; i ++ ) {
				scene.add( nodes[ i ] );
			}
			// Removes dangling associations, associations that reference a node that
			// didn't make it into the scene.
			const reduceAssociations = ( node ) => {
				const reducedAssociations = new Map();
				for ( const [ key, value ] of parser.associations ) {
					if ( key instanceof Material || key instanceof Texture ) {
						reducedAssociations.set( key, value );
					}
				}
				node.traverse( ( node ) => {
					const mappings = parser.associations.get( node );
					if ( mappings != null ) {
						reducedAssociations.set( node, mappings );
					}
				} );
				return reducedAssociations;
			};
			parser.associations = reduceAssociations( scene );
			return scene;
		} );
	}
	_createAnimationTracks( node, inputAccessor, outputAccessor, sampler, target ) {
		const tracks = [];
		const targetName = node.name ? node.name : node.uuid;
		const targetNames = [];
		if ( PATH_PROPERTIES[ target.path ] === PATH_PROPERTIES.weights ) {
			node.traverse( function ( object ) {
				if ( object.morphTargetInfluences ) {
					targetNames.push( object.name ? object.name : object.uuid );
				}
			} );
		} else {
			targetNames.push( targetName );
		}
		let TypedKeyframeTrack;
		switch ( PATH_PROPERTIES[ target.path ] ) {
			case PATH_PROPERTIES.weights:
				TypedKeyframeTrack = NumberKeyframeTrack;
				break;
			case PATH_PROPERTIES.rotation:
				TypedKeyframeTrack = QuaternionKeyframeTrack;
				break;
			case PATH_PROPERTIES.position:
			case PATH_PROPERTIES.scale:
				TypedKeyframeTrack = VectorKeyframeTrack;
				break;
			default:
				switch ( outputAccessor.itemSize ) {
					case 1:
						TypedKeyframeTrack = NumberKeyframeTrack;
						break;
					case 2:
					case 3:
					default:
						TypedKeyframeTrack = VectorKeyframeTrack;
						break;
				}
				break;
		}
		const interpolation = sampler.interpolation !== undefined ? INTERPOLATION[ sampler.interpolation ] : InterpolateLinear;
		const outputArray = this._getArrayFromAccessor( outputAccessor );
		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' ) {
				this._createCubicSplineTrackInterpolant( track );
			}
			tracks.push( track );
		}
		return tracks;
	}
	_getArrayFromAccessor( accessor ) {
		let outputArray = accessor.array;
		if ( accessor.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;
		}
		return outputArray;
	}
	_createCubicSplineTrackInterpolant( track ) {
		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 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;
	}
}
/**
 * @param {BufferGeometry} geometry
 * @param {GLTF.Primitive} primitiveDef
 * @param {GLTFParser} parser
 */
function computeBounds( geometry, primitiveDef, parser ) {
	const attributes = primitiveDef.attributes;
	const box = new 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 Vector3( min[ 0 ], min[ 1 ], min[ 2 ] ),
				new 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 Vector3();
		const vector = new 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 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 );
	}
	if ( ColorManagement.workingColorSpace !== LinearSRGBColorSpace && 'COLOR_0' in attributes ) {
		console.warn( `THREE.GLTFLoader: Converting vertex colors from "srgb-linear" to "${ColorManagement.workingColorSpace}" not supported.` );
	}
	assignExtrasToUserData( geometry, primitiveDef );
	computeBounds( geometry, primitiveDef, parser );
	return Promise.all( pending ).then( function () {
		return primitiveDef.targets !== undefined
			? addMorphTargets( geometry, primitiveDef.targets, parser )
			: geometry;
	} );
}
export { GLTFLoader };