GLTFLoader.js

import * as THREE from 'three';
import { LoaderUtils } from './LoaderUtils';
/**
 * @author Rich Tibbett / https://github.com/richtr
 * @author mrdoob / http://mrdoob.com/
 * @author Tony Parisi / http://www.tonyparisi.com/
 * @author Takahiro / https://github.com/takahirox
 * @author Don McCurdy / https://www.donmccurdy.com
 */

THREE.GLTFLoader = ( function () {
    
        function GLTFLoader( manager ) {
    
            this.manager = ( manager !== undefined ) ? manager : THREE.DefaultLoadingManager;
    
        }
    
        GLTFLoader.prototype = {
    
            constructor: GLTFLoader,
    
            crossOrigin: 'Anonymous',
    
            load: function ( url, onLoad, onProgress, onError ) {
    
                var scope = this;
    
                var path = this.path !== undefined ? this.path : LoaderUtils.extractUrlBase( url );
    
                var loader = new THREE.FileLoader( scope.manager );
    
                loader.setResponseType( 'arraybuffer' );
    
                loader.load( url, function ( data ) {
    
                    try {
    
                        scope.parse( data, path, onLoad, onError );
    
                    } catch ( e ) {
    
                        if ( onError !== undefined ) {
    
                            onError( e );
    
                        } else {
    
                            throw e;
    
                        }
    
                    }
    
                }, onProgress, onError );
    
            },
    
            setCrossOrigin: function ( value ) {
    
                this.crossOrigin = value;
                return this;
    
            },
    
            setPath: function ( value ) {
    
                this.path = value;
                return this;
    
            },
    
            parse: function ( data, path, onLoad, onError ) {
    
                var content;
                var extensions = {};
    
                if ( typeof data === 'string' ) {
    
                    content = data;
    
                } else {
    
                    var magic = LoaderUtils.decodeText( new Uint8Array( data, 0, 4 ) );
    
                    if ( magic === BINARY_EXTENSION_HEADER_MAGIC ) {
    
                        try {
    
                            extensions[ EXTENSIONS.KHR_BINARY_GLTF ] = new GLTFBinaryExtension( data );
    
                        } catch ( error ) {
    
                            if ( onError ) onError( error );
                            return;
    
                        }
    
                        content = extensions[ EXTENSIONS.KHR_BINARY_GLTF ].content;
    
                    } else {
    
                        content = LoaderUtils.decodeText( new Uint8Array( data ) );
    
                    }
    
                }
    
                var json = JSON.parse( content );
    
                if ( json.asset === undefined || json.asset.version[ 0 ] < 2 ) {
    
                    if ( onError ) onError( new Error( 'THREE.GLTFLoader: Unsupported asset. glTF versions >=2.0 are supported. Use LegacyGLTFLoader instead.' ) );
                    return;
    
                }
    
                if ( json.extensionsUsed ) {
    
                    if ( json.extensionsUsed.indexOf( EXTENSIONS.KHR_LIGHTS ) >= 0 ) {
    
                        extensions[ EXTENSIONS.KHR_LIGHTS ] = new GLTFLightsExtension( json );
    
                    }
    
                    if ( json.extensionsUsed.indexOf( EXTENSIONS.KHR_MATERIALS_COMMON ) >= 0 ) {
    
                        extensions[ EXTENSIONS.KHR_MATERIALS_COMMON ] = new GLTFMaterialsCommonExtension( json );
    
                    }
    
                    if ( json.extensionsUsed.indexOf( EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS ) >= 0 ) {
    
                        extensions[ EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS ] = new GLTFMaterialsPbrSpecularGlossinessExtension();
    
                    }
    
                }
    
                console.time( 'GLTFLoader' );
    
                var parser = new GLTFParser( json, extensions, {
    
                    path: path || this.path || '',
                    crossOrigin: this.crossOrigin,
                    manager: this.manager
    
                } );
    
                parser.parse( function ( scene, scenes, cameras, animations, asset ) {
    
                    console.timeEnd( 'GLTFLoader' );
    
                    var glTF = {
                        scene: scene,
                        scenes: scenes,
                        cameras: cameras,
                        animations: animations,
                        asset: asset
                    };
    
                    onLoad( glTF );
    
                }, onError );
    
            }
    
        };
    
        /* GLTFREGISTRY */
    
        function GLTFRegistry() {
    
            var objects = {};
    
            return	{
    
                get: function ( key ) {
    
                    return objects[ key ];
    
                },
    
                add: function ( key, object ) {
    
                    objects[ key ] = object;
    
                },
    
                remove: function ( key ) {
    
                    delete objects[ key ];
    
                },
    
                removeAll: function () {
    
                    objects = {};
    
                }
    
            };
    
        }
    
        /*********************************/
        /********** EXTENSIONS ***********/
        /*********************************/
    
        var EXTENSIONS = {
            KHR_BINARY_GLTF: 'KHR_binary_glTF',
            KHR_LIGHTS: 'KHR_lights',
            KHR_MATERIALS_COMMON: 'KHR_materials_common',
            KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS: 'KHR_materials_pbrSpecularGlossiness'
        };
    
        /**
         * Lights Extension
         *
         * Specification: PENDING
         */
        function GLTFLightsExtension( json ) {
    
            this.name = EXTENSIONS.KHR_LIGHTS;
    
            this.lights = {};
    
            var extension = ( json.extensions && json.extensions[ EXTENSIONS.KHR_LIGHTS ] ) || {};
            var lights = extension.lights || {};
    
            for ( var lightId in lights ) {
    
                var light = lights[ lightId ];
                var lightNode;
    
                var color = new THREE.Color().fromArray( light.color );
    
                switch ( light.type ) {
    
                    case 'directional':
                        lightNode = new THREE.DirectionalLight( color );
                        lightNode.position.set( 0, 0, 1 );
                        break;
    
                    case 'point':
                        lightNode = new THREE.PointLight( color );
                        break;
    
                    case 'spot':
                        lightNode = new THREE.SpotLight( color );
                        lightNode.position.set( 0, 0, 1 );
                        break;
    
                    case 'ambient':
                        lightNode = new THREE.AmbientLight( color );
                        break;
    
                }
    
                if ( lightNode ) {
    
                    if ( light.constantAttenuation !== undefined ) {
    
                        lightNode.intensity = light.constantAttenuation;
    
                    }
    
                    if ( light.linearAttenuation !== undefined ) {
    
                        lightNode.distance = 1 / light.linearAttenuation;
    
                    }
    
                    if ( light.quadraticAttenuation !== undefined ) {
    
                        lightNode.decay = light.quadraticAttenuation;
    
                    }
    
                    if ( light.fallOffAngle !== undefined ) {
    
                        lightNode.angle = light.fallOffAngle;
    
                    }
    
                    if ( light.fallOffExponent !== undefined ) {
    
                        console.warn( 'THREE.GLTFLoader:: light.fallOffExponent not currently supported.' );
    
                    }
    
                    lightNode.name = light.name || ( 'light_' + lightId );
                    this.lights[ lightId ] = lightNode;
    
                }
    
            }
    
        }
    
        /**
         * Common Materials Extension
         *
         * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/Khronos/KHR_materials_common
         */
        function GLTFMaterialsCommonExtension( json ) {
    
            this.name = EXTENSIONS.KHR_MATERIALS_COMMON;
    
        }
    
        GLTFMaterialsCommonExtension.prototype.getMaterialType = function ( material ) {
    
            var khrMaterial = material.extensions[ this.name ];
    
            switch ( khrMaterial.type ) {
    
                case 'commonBlinn' :
                case 'commonPhong' :
                    return THREE.MeshPhongMaterial;
    
                case 'commonLambert' :
                    return THREE.MeshLambertMaterial;
    
                case 'commonConstant' :
                default :
                    return THREE.MeshBasicMaterial;
    
            }
    
        };
    
        GLTFMaterialsCommonExtension.prototype.extendParams = function ( materialParams, material, parser ) {
    
            var khrMaterial = material.extensions[ this.name ];
    
            var pending = [];
    
            var keys = [];
    
            // TODO: Currently ignored: 'ambientFactor', 'ambientTexture'
            switch ( khrMaterial.type ) {
    
                case 'commonBlinn' :
                case 'commonPhong' :
                    keys.push( 'diffuseFactor', 'diffuseTexture', 'specularFactor', 'specularTexture', 'shininessFactor' );
                    break;
    
                case 'commonLambert' :
                    keys.push( 'diffuseFactor', 'diffuseTexture' );
                    break;
    
                case 'commonConstant' :
                default :
                    break;
    
            }
    
            var materialValues = {};
    
            keys.forEach( function ( v ) {
    
                if ( khrMaterial[ v ] !== undefined ) materialValues[ v ] = khrMaterial[ v ];
    
            } );
    
            if ( materialValues.diffuseFactor !== undefined ) {
    
                materialParams.color = new THREE.Color().fromArray( materialValues.diffuseFactor );
                materialParams.opacity = materialValues.diffuseFactor[ 3 ];
    
            }
    
            if ( materialValues.diffuseTexture !== undefined ) {
    
                pending.push( parser.assignTexture( materialParams, 'map', materialValues.diffuseTexture.index ) );
    
            }
    
            if ( materialValues.specularFactor !== undefined ) {
    
                materialParams.specular = new THREE.Color().fromArray( materialValues.specularFactor );
    
            }
    
            if ( materialValues.specularTexture !== undefined ) {
    
                pending.push( parser.assignTexture( materialParams, 'specularMap', materialValues.specularTexture.index ) );
    
            }
    
            if ( materialValues.shininessFactor !== undefined ) {
    
                materialParams.shininess = materialValues.shininessFactor;
    
            }
    
            return Promise.all( pending );
    
        };
    
        /* BINARY EXTENSION */
    
        var BINARY_EXTENSION_BUFFER_NAME = 'binary_glTF';
        var BINARY_EXTENSION_HEADER_MAGIC = 'glTF';
        var BINARY_EXTENSION_HEADER_LENGTH = 12;
        var BINARY_EXTENSION_CHUNK_TYPES = { JSON: 0x4E4F534A, BIN: 0x004E4942 };
    
        function GLTFBinaryExtension( data ) {
    
            this.name = EXTENSIONS.KHR_BINARY_GLTF;
            this.content = null;
            this.body = null;
    
            var headerView = new DataView( data, 0, BINARY_EXTENSION_HEADER_LENGTH );
    
            this.header = {
                magic: LoaderUtils.decodeText( new Uint8Array( data.slice( 0, 4 ) ) ),
                version: headerView.getUint32( 4, true ),
                length: headerView.getUint32( 8, true )
            };
    
            if ( this.header.magic !== BINARY_EXTENSION_HEADER_MAGIC ) {
    
                throw new Error( 'THREE.GLTFLoader: Unsupported glTF-Binary header.' );
    
            } else if ( this.header.version < 2.0 ) {
    
                throw new Error( 'THREE.GLTFLoader: Legacy binary file detected. Use LegacyGLTFLoader instead.' );
    
            }
    
            var chunkView = new DataView( data, BINARY_EXTENSION_HEADER_LENGTH );
            var chunkIndex = 0;
    
            while ( chunkIndex < chunkView.byteLength ) {
    
                var chunkLength = chunkView.getUint32( chunkIndex, true );
                chunkIndex += 4;
    
                var chunkType = chunkView.getUint32( chunkIndex, true );
                chunkIndex += 4;
    
                if ( chunkType === BINARY_EXTENSION_CHUNK_TYPES.JSON ) {
    
                    var contentArray = new Uint8Array( data, BINARY_EXTENSION_HEADER_LENGTH + chunkIndex, chunkLength );
                    this.content = LoaderUtils.decodeText( contentArray );
    
                } else if ( chunkType === BINARY_EXTENSION_CHUNK_TYPES.BIN ) {
    
                    var byteOffset = BINARY_EXTENSION_HEADER_LENGTH + chunkIndex;
                    this.body = data.slice( byteOffset, byteOffset + chunkLength );
    
                }
    
                // Clients must ignore chunks with unknown types.
    
                chunkIndex += chunkLength;
    
            }
    
            if ( this.content === null ) {
    
                throw new Error( 'THREE.GLTFLoader: JSON content not found.' );
    
            }
    
        }
    
        /**
         * Specular-Glossiness Extension
         *
         * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/Khronos/KHR_materials_pbrSpecularGlossiness
         */
        function GLTFMaterialsPbrSpecularGlossinessExtension() {
    
            return {
    
                name: EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS,
    
                specularGlossinessParams: [
                    'color',
                    'map',
                    'lightMap',
                    'lightMapIntensity',
                    'aoMap',
                    'aoMapIntensity',
                    'emissive',
                    'emissiveIntensity',
                    'emissiveMap',
                    'bumpMap',
                    'bumpScale',
                    'normalMap',
                    'displacementMap',
                    'displacementScale',
                    'displacementBias',
                    'specularMap',
                    'specular',
                    'glossinessMap',
                    'glossiness',
                    'alphaMap',
                    'envMap',
                    'envMapIntensity',
                    'refractionRatio',
                ],
    
                getMaterialType: function () {
    
                    return THREE.ShaderMaterial;
    
                },
    
                extendParams: function ( params, material, parser ) {
    
                    var pbrSpecularGlossiness = material.extensions[ this.name ];
    
                    var shader = THREE.ShaderLib[ 'standard' ];
    
                    var uniforms = THREE.UniformsUtils.clone( shader.uniforms );
    
                    var specularMapParsFragmentChunk = [
                        '#ifdef USE_SPECULARMAP',
                        '	uniform sampler2D specularMap;',
                        '#endif'
                    ].join( '\n' );
    
                    var glossinessMapParsFragmentChunk = [
                        '#ifdef USE_GLOSSINESSMAP',
                        '	uniform sampler2D glossinessMap;',
                        '#endif'
                    ].join( '\n' );
    
                    var specularMapFragmentChunk = [
                        'vec3 specularFactor = specular;',
                        '#ifdef USE_SPECULARMAP',
                        '	vec4 texelSpecular = texture2D( specularMap, vUv );',
                        '	texelSpecular = sRGBToLinear( texelSpecular );',
                        '	// reads channel RGB, compatible with a glTF Specular-Glossiness (RGBA) texture',
                        '	specularFactor *= texelSpecular.rgb;',
                        '#endif'
                    ].join( '\n' );
    
                    var glossinessMapFragmentChunk = [
                        'float glossinessFactor = glossiness;',
                        '#ifdef USE_GLOSSINESSMAP',
                        '	vec4 texelGlossiness = texture2D( glossinessMap, vUv );',
                        '	// reads channel A, compatible with a glTF Specular-Glossiness (RGBA) texture',
                        '	glossinessFactor *= texelGlossiness.a;',
                        '#endif'
                    ].join( '\n' );
    
                    var lightPhysicalFragmentChunk = [
                        'PhysicalMaterial material;',
                        'material.diffuseColor = diffuseColor.rgb;',
                        'material.specularRoughness = clamp( 1.0 - glossinessFactor, 0.04, 1.0 );',
                        'material.specularColor = specularFactor.rgb;',
                    ].join( '\n' );
    
                    var fragmentShader = shader.fragmentShader
                        .replace( '#include <specularmap_fragment>', '' )
                        .replace( 'uniform float roughness;', 'uniform vec3 specular;' )
                        .replace( 'uniform float metalness;', 'uniform float glossiness;' )
                        .replace( '#include <roughnessmap_pars_fragment>', specularMapParsFragmentChunk )
                        .replace( '#include <metalnessmap_pars_fragment>', glossinessMapParsFragmentChunk )
                        .replace( '#include <roughnessmap_fragment>', specularMapFragmentChunk )
                        .replace( '#include <metalnessmap_fragment>', glossinessMapFragmentChunk )
                        .replace( '#include <lights_physical_fragment>', lightPhysicalFragmentChunk );
    
                    delete uniforms.roughness;
                    delete uniforms.metalness;
                    delete uniforms.roughnessMap;
                    delete uniforms.metalnessMap;
    
                    uniforms.specular = { value: new THREE.Color().setHex( 0x111111 ) };
                    uniforms.glossiness = { value: 0.5 };
                    uniforms.specularMap = { value: null };
                    uniforms.glossinessMap = { value: null };
    
                    params.vertexShader = shader.vertexShader;
                    params.fragmentShader = fragmentShader;
                    params.uniforms = uniforms;
                    params.defines = { 'STANDARD': '' };
    
                    params.color = new THREE.Color( 1.0, 1.0, 1.0 );
                    params.opacity = 1.0;
    
                    var pending = [];
    
                    if ( Array.isArray( pbrSpecularGlossiness.diffuseFactor ) ) {
    
                        var array = pbrSpecularGlossiness.diffuseFactor;
    
                        params.color.fromArray( array );
                        params.opacity = array[ 3 ];
    
                    }
    
                    if ( pbrSpecularGlossiness.diffuseTexture !== undefined ) {
    
                        pending.push( parser.assignTexture( params, 'map', pbrSpecularGlossiness.diffuseTexture.index ) );
    
                    }
    
                    params.emissive = new THREE.Color( 0.0, 0.0, 0.0 );
                    params.glossiness = pbrSpecularGlossiness.glossinessFactor !== undefined ? pbrSpecularGlossiness.glossinessFactor : 1.0;
                    params.specular = new THREE.Color( 1.0, 1.0, 1.0 );
    
                    if ( Array.isArray( pbrSpecularGlossiness.specularFactor ) ) {
    
                        params.specular.fromArray( pbrSpecularGlossiness.specularFactor );
    
                    }
    
                    if ( pbrSpecularGlossiness.specularGlossinessTexture !== undefined ) {
    
                        var specGlossIndex = pbrSpecularGlossiness.specularGlossinessTexture.index;
                        pending.push( parser.assignTexture( params, 'glossinessMap', specGlossIndex ) );
                        pending.push( parser.assignTexture( params, 'specularMap', specGlossIndex ) );
    
                    }
    
                    return Promise.all( pending );
    
                },
    
                createMaterial: function ( params ) {
    
                    // setup material properties based on MeshStandardMaterial for Specular-Glossiness
    
                    var material = new THREE.ShaderMaterial( {
                        defines: params.defines,
                        vertexShader: params.vertexShader,
                        fragmentShader: params.fragmentShader,
                        uniforms: params.uniforms,
                        fog: true,
                        lights: true,
                        opacity: params.opacity,
                        transparent: params.transparent
                    } );
    
                    material.isGLTFSpecularGlossinessMaterial = true;
    
                    material.color = params.color;
    
                    material.map = params.map === undefined ? null : params.map;
    
                    material.lightMap = null;
                    material.lightMapIntensity = 1.0;
    
                    material.aoMap = params.aoMap === undefined ? null : params.aoMap;
                    material.aoMapIntensity = 1.0;
    
                    material.emissive = params.emissive;
                    material.emissiveIntensity = 1.0;
                    material.emissiveMap = params.emissiveMap === undefined ? null : params.emissiveMap;
    
                    material.bumpMap = params.bumpMap === undefined ? null : params.bumpMap;
                    material.bumpScale = 1;
    
                    material.normalMap = params.normalMap === undefined ? null : params.normalMap;
                    if ( params.normalScale ) material.normalScale = params.normalScale;
    
                    material.displacementMap = null;
                    material.displacementScale = 1;
                    material.displacementBias = 0;
    
                    material.specularMap = params.specularMap === undefined ? null : params.specularMap;
                    material.specular = params.specular;
    
                    material.glossinessMap = params.glossinessMap === undefined ? null : params.glossinessMap;
                    material.glossiness = params.glossiness;
    
                    material.alphaMap = null;
    
                    material.envMap = params.envMap === undefined ? null : params.envMap;
                    material.envMapIntensity = 1.0;
    
                    material.refractionRatio = 0.98;
    
                    material.extensions.derivatives = true;
    
                    return material;
    
                },
    
                /**
                 * Clones a GLTFSpecularGlossinessMaterial instance. The ShaderMaterial.copy() method can
                 * copy only properties it knows about or inherits, and misses many properties that would
                 * normally be defined by MeshStandardMaterial.
                 *
                 * This method allows GLTFSpecularGlossinessMaterials to be cloned in the process of
                 * loading a glTF model, but cloning later (e.g. by the user) would require these changes
                 * AND also updating `.onBeforeRender` on the parent mesh.
                 *
                 * @param  {THREE.ShaderMaterial} source
                 * @return {THREE.ShaderMaterial}
                 */
                cloneMaterial: function ( source ) {
    
                    var target = source.clone();
    
                    target.isGLTFSpecularGlossinessMaterial = true;
    
                    var params = this.specularGlossinessParams;
    
                    for ( var i = 0, il = params.length; i < il; i ++ ) {
    
                        target[ params[ i ] ] = source[ params[ i ] ];
    
                    }
    
                    return target;
    
                },
    
                // Here's based on refreshUniformsCommon() and refreshUniformsStandard() in WebGLRenderer.
                refreshUniforms: function ( renderer, scene, camera, geometry, material, group ) {
    
                    var uniforms = material.uniforms;
                    var defines = material.defines;
    
                    uniforms.opacity.value = material.opacity;
    
                    uniforms.diffuse.value.copy( material.color );
                    uniforms.emissive.value.copy( material.emissive ).multiplyScalar( material.emissiveIntensity );
    
                    uniforms.map.value = material.map;
                    uniforms.specularMap.value = material.specularMap;
                    uniforms.alphaMap.value = material.alphaMap;
    
                    uniforms.lightMap.value = material.lightMap;
                    uniforms.lightMapIntensity.value = material.lightMapIntensity;
    
                    uniforms.aoMap.value = material.aoMap;
                    uniforms.aoMapIntensity.value = material.aoMapIntensity;
    
                    // uv repeat and offset setting priorities
                    // 1. color map
                    // 2. specular map
                    // 3. normal map
                    // 4. bump map
                    // 5. alpha map
                    // 6. emissive map
    
                    var uvScaleMap;
    
                    if ( material.map ) {
    
                        uvScaleMap = material.map;
    
                    } else if ( material.specularMap ) {
    
                        uvScaleMap = material.specularMap;
    
                    } else if ( material.displacementMap ) {
    
                        uvScaleMap = material.displacementMap;
    
                    } else if ( material.normalMap ) {
    
                        uvScaleMap = material.normalMap;
    
                    } else if ( material.bumpMap ) {
    
                        uvScaleMap = material.bumpMap;
    
                    } else if ( material.glossinessMap ) {
    
                        uvScaleMap = material.glossinessMap;
    
                    } else if ( material.alphaMap ) {
    
                        uvScaleMap = material.alphaMap;
    
                    } else if ( material.emissiveMap ) {
    
                        uvScaleMap = material.emissiveMap;
    
                    }
    
                    if ( uvScaleMap !== undefined ) {
    
                        // backwards compatibility
                        if ( uvScaleMap.isWebGLRenderTarget ) {
    
                            uvScaleMap = uvScaleMap.texture;
    
                        }
    
                        var offset;
                        var repeat;
    
                        if ( uvScaleMap.matrix !== undefined ) {
    
                            // > r88.
    
                            if ( uvScaleMap.matrixAutoUpdate === true ) {
    
                                offset = uvScaleMap.offset;
                                repeat = uvScaleMap.repeat;
                                var rotation = uvScaleMap.rotation;
                                var center = uvScaleMap.center;
    
                                uvScaleMap.matrix.setUvTransform( offset.x, offset.y, repeat.x, repeat.y, rotation, center.x, center.y );
    
                            }
    
                            uniforms.uvTransform.value.copy( uvScaleMap.matrix );
    
                        } else {
    
                            // <= r87. Remove when reasonable.
    
                            offset = uvScaleMap.offset;
                            repeat = uvScaleMap.repeat;
    
                            uniforms.offsetRepeat.value.set( offset.x, offset.y, repeat.x, repeat.y );
    
                        }
    
                    }
    
                    uniforms.envMap.value = material.envMap;
                    uniforms.envMapIntensity.value = material.envMapIntensity;
                    uniforms.flipEnvMap.value = ( material.envMap && material.envMap.isCubeTexture ) ? - 1 : 1;
    
                    uniforms.refractionRatio.value = material.refractionRatio;
    
                    uniforms.specular.value.copy( material.specular );
                    uniforms.glossiness.value = material.glossiness;
    
                    uniforms.glossinessMap.value = material.glossinessMap;
    
                    uniforms.emissiveMap.value = material.emissiveMap;
                    uniforms.bumpMap.value = material.bumpMap;
                    uniforms.normalMap.value = material.normalMap;
    
                    uniforms.displacementMap.value = material.displacementMap;
                    uniforms.displacementScale.value = material.displacementScale;
                    uniforms.displacementBias.value = material.displacementBias;
    
                    if ( uniforms.glossinessMap.value !== null && defines.USE_GLOSSINESSMAP === undefined ) {
    
                        defines.USE_GLOSSINESSMAP = '';
                        // set USE_ROUGHNESSMAP to enable vUv
                        defines.USE_ROUGHNESSMAP = '';
    
                    }
    
                    if ( uniforms.glossinessMap.value === null && defines.USE_GLOSSINESSMAP !== undefined ) {
    
                        delete defines.USE_GLOSSINESSMAP;
                        delete defines.USE_ROUGHNESSMAP;
    
                    }
    
                }
    
            };
    
        }
    
        /*********************************/
        /********** INTERNALS ************/
        /*********************************/
    
        /* CONSTANTS */
    
        var WEBGL_CONSTANTS = {
            FLOAT: 5126,
            //FLOAT_MAT2: 35674,
            FLOAT_MAT3: 35675,
            FLOAT_MAT4: 35676,
            FLOAT_VEC2: 35664,
            FLOAT_VEC3: 35665,
            FLOAT_VEC4: 35666,
            LINEAR: 9729,
            REPEAT: 10497,
            SAMPLER_2D: 35678,
            POINTS: 0,
            LINES: 1,
            LINE_LOOP: 2,
            LINE_STRIP: 3,
            TRIANGLES: 4,
            TRIANGLE_STRIP: 5,
            TRIANGLE_FAN: 6,
            UNSIGNED_BYTE: 5121,
            UNSIGNED_SHORT: 5123
        };
    
        var WEBGL_TYPE = {
            5126: Number,
            //35674: THREE.Matrix2,
            35675: THREE.Matrix3,
            35676: THREE.Matrix4,
            35664: THREE.Vector2,
            35665: THREE.Vector3,
            35666: THREE.Vector4,
            35678: THREE.Texture
        };
    
        var WEBGL_COMPONENT_TYPES = {
            5120: Int8Array,
            5121: Uint8Array,
            5122: Int16Array,
            5123: Uint16Array,
            5125: Uint32Array,
            5126: Float32Array
        };
    
        var WEBGL_FILTERS = {
            9728: THREE.NearestFilter,
            9729: THREE.LinearFilter,
            9984: THREE.NearestMipMapNearestFilter,
            9985: THREE.LinearMipMapNearestFilter,
            9986: THREE.NearestMipMapLinearFilter,
            9987: THREE.LinearMipMapLinearFilter
        };
    
        var WEBGL_WRAPPINGS = {
            33071: THREE.ClampToEdgeWrapping,
            33648: THREE.MirroredRepeatWrapping,
            10497: THREE.RepeatWrapping
        };
    
        var WEBGL_TEXTURE_FORMATS = {
            6406: THREE.AlphaFormat,
            6407: THREE.RGBFormat,
            6408: THREE.RGBAFormat,
            6409: THREE.LuminanceFormat,
            6410: THREE.LuminanceAlphaFormat
        };
    
        var WEBGL_TEXTURE_DATATYPES = {
            5121: THREE.UnsignedByteType,
            32819: THREE.UnsignedShort4444Type,
            32820: THREE.UnsignedShort5551Type,
            33635: THREE.UnsignedShort565Type
        };
    
        var WEBGL_SIDES = {
            1028: THREE.BackSide, // Culling front
            1029: THREE.FrontSide // Culling back
            //1032: THREE.NoSide   // Culling front and back, what to do?
        };
    
        var WEBGL_DEPTH_FUNCS = {
            512: THREE.NeverDepth,
            513: THREE.LessDepth,
            514: THREE.EqualDepth,
            515: THREE.LessEqualDepth,
            516: THREE.GreaterEqualDepth,
            517: THREE.NotEqualDepth,
            518: THREE.GreaterEqualDepth,
            519: THREE.AlwaysDepth
        };
    
        var WEBGL_BLEND_EQUATIONS = {
            32774: THREE.AddEquation,
            32778: THREE.SubtractEquation,
            32779: THREE.ReverseSubtractEquation
        };
    
        var WEBGL_BLEND_FUNCS = {
            0: THREE.ZeroFactor,
            1: THREE.OneFactor,
            768: THREE.SrcColorFactor,
            769: THREE.OneMinusSrcColorFactor,
            770: THREE.SrcAlphaFactor,
            771: THREE.OneMinusSrcAlphaFactor,
            772: THREE.DstAlphaFactor,
            773: THREE.OneMinusDstAlphaFactor,
            774: THREE.DstColorFactor,
            775: THREE.OneMinusDstColorFactor,
            776: THREE.SrcAlphaSaturateFactor
            // The followings are not supported by Three.js yet
            //32769: CONSTANT_COLOR,
            //32770: ONE_MINUS_CONSTANT_COLOR,
            //32771: CONSTANT_ALPHA,
            //32772: ONE_MINUS_CONSTANT_COLOR
        };
    
        var WEBGL_TYPE_SIZES = {
            'SCALAR': 1,
            'VEC2': 2,
            'VEC3': 3,
            'VEC4': 4,
            'MAT2': 4,
            'MAT3': 9,
            'MAT4': 16
        };
    
        var PATH_PROPERTIES = {
            scale: 'scale',
            translation: 'position',
            rotation: 'quaternion',
            weights: 'morphTargetInfluences'
        };
    
        var INTERPOLATION = {
            CUBICSPLINE: THREE.InterpolateSmooth,
            LINEAR: THREE.InterpolateLinear,
            STEP: THREE.InterpolateDiscrete
        };
    
        var STATES_ENABLES = {
            2884: 'CULL_FACE',
            2929: 'DEPTH_TEST',
            3042: 'BLEND',
            3089: 'SCISSOR_TEST',
            32823: 'POLYGON_OFFSET_FILL',
            32926: 'SAMPLE_ALPHA_TO_COVERAGE'
        };
    
        var ALPHA_MODES = {
            OPAQUE: 'OPAQUE',
            MASK: 'MASK',
            BLEND: 'BLEND'
        };
    
        /* UTILITY FUNCTIONS */
    
        function resolveURL( url, path ) {
    
            // Invalid URL
            if ( typeof url !== 'string' || url === '' ) return '';
    
            // Absolute URL http://,https://,//
            if ( /^(https?:)?\/\//i.test( url ) ) return url;
    
            // Data URI
            if ( /^data:.*,.*$/i.test( url ) ) return url;
    
            // Blob URL
            if ( /^blob:.*$/i.test( url ) ) return url;
    
            // Relative URL
            return path + url;
    
        }
    
        /**
         * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#default-material
         */
        function createDefaultMaterial() {
    
            return new THREE.MeshStandardMaterial( {
                color: 0xFFFFFF,
                emissive: 0x000000,
                metalness: 1,
                roughness: 1,
                transparent: false,
                depthTest: true,
                side: THREE.FrontSide
            } );
    
        }
    
        /**
         * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#morph-targets
         *
         * TODO: Implement support for morph targets on TANGENT attribute.
         *
         * @param {THREE.Mesh} mesh
         * @param {GLTF.Mesh} meshDef
         * @param {GLTF.Primitive} primitiveDef
         * @param {Array<THREE.BufferAttribute>} accessors
         */
        function addMorphTargets( mesh, meshDef, primitiveDef, accessors ) {
    
            var geometry = mesh.geometry;
            var material = mesh.material;
    
            var targets = primitiveDef.targets;
            var morphAttributes = geometry.morphAttributes;
    
            morphAttributes.position = [];
            morphAttributes.normal = [];
    
            material.morphTargets = true;
    
            for ( var i = 0, il = targets.length; i < il; i ++ ) {
    
                var target = targets[ i ];
                var attributeName = 'morphTarget' + i;
    
                var positionAttribute, normalAttribute;
    
                if ( target.POSITION !== undefined ) {
    
                    // Three.js morph formula is
                    //   position
                    //     + weight0 * ( morphTarget0 - position )
                    //     + weight1 * ( morphTarget1 - position )
                    //     ...
                    // while the glTF one is
                    //   position
                    //     + weight0 * morphTarget0
                    //     + weight1 * morphTarget1
                    //     ...
                    // then adding position to morphTarget.
                    // So morphTarget value will depend on mesh's position, then cloning attribute
                    // for the case if attribute is shared among two or more meshes.
    
                    positionAttribute = accessors[ target.POSITION ].clone();
                    var position = geometry.attributes.position;
    
                    for ( var j = 0, jl = positionAttribute.count; j < jl; j ++ ) {
    
                        positionAttribute.setXYZ(
                            j,
                            positionAttribute.getX( j ) + position.getX( j ),
                            positionAttribute.getY( j ) + position.getY( j ),
                            positionAttribute.getZ( j ) + position.getZ( j )
                        );
    
                    }
    
                } else if ( geometry.attributes.position ) {
    
                    // Copying the original position not to affect the final position.
                    // See the formula above.
                    positionAttribute = geometry.attributes.position.clone();
    
                }
    
                if ( positionAttribute !== undefined ) {
    
                    positionAttribute.name = attributeName;
                    morphAttributes.position.push( positionAttribute );
    
                }
    
                if ( target.NORMAL !== undefined ) {
    
                    material.morphNormals = true;
    
                    // see target.POSITION's comment
    
                    normalAttribute = accessors[ target.NORMAL ].clone();
                    var normal = geometry.attributes.normal;
    
                    for ( var j = 0, jl = normalAttribute.count; j < jl; j ++ ) {
    
                        normalAttribute.setXYZ(
                            j,
                            normalAttribute.getX( j ) + normal.getX( j ),
                            normalAttribute.getY( j ) + normal.getY( j ),
                            normalAttribute.getZ( j ) + normal.getZ( j )
                        );
    
                    }
    
                } else if ( geometry.attributes.normal !== undefined ) {
    
                    normalAttribute = geometry.attributes.normal.clone();
    
                }
    
                if ( normalAttribute !== undefined ) {
    
                    normalAttribute.name = attributeName;
                    morphAttributes.normal.push( normalAttribute );
    
                }
    
            }
    
            mesh.updateMorphTargets();
    
            if ( meshDef.weights !== undefined ) {
    
                for ( var i = 0, il = meshDef.weights.length; i < il; i ++ ) {
    
                    mesh.morphTargetInfluences[ i ] = meshDef.weights[ i ];
    
                }
    
            }
    
        }
    
        function isPrimitiveEqual( a, b ) {
    
            if ( a.indices !== b.indices ) {
    
                return false;
    
            }
    
            var attribA = a.attributes || {};
            var attribB = b.attributes || {};
            var keysA = Object.keys( attribA );
            var keysB = Object.keys( attribB );
    
            if ( keysA.length !== keysB.length ) {
    
                return false;
    
            }
    
            for ( var i = 0, il = keysA.length; i < il; i ++ ) {
    
                var key = keysA[ i ];
    
                if ( attribA[ key ] !== attribB[ key ] ) {
    
                    return false;
    
                }
    
            }
    
            return true;
    
        }
    
        function getCachedGeometry( cache, newPrimitive ) {
    
            for ( var i = 0, il = cache.length; i < il; i ++ ) {
    
                var cached = cache[ i ];
    
                if ( isPrimitiveEqual( cached.primitive, newPrimitive ) ) {
    
                    return cached.geometry;
    
                }
    
            }
    
            return null;
    
        }
    
        /* GLTF PARSER */
    
        function GLTFParser( json, extensions, options ) {
    
            this.json = json || {};
            this.extensions = extensions || {};
            this.options = options || {};
    
            // loader object cache
            this.cache = new GLTFRegistry();
    
            // BufferGeometry caching
            this.primitiveCache = [];
    
            this.textureLoader = new THREE.TextureLoader( this.options.manager );
            this.textureLoader.setCrossOrigin( this.options.crossOrigin );
    
            this.fileLoader = new THREE.FileLoader( this.options.manager );
            this.fileLoader.setResponseType( 'arraybuffer' );
    
        }
    
        GLTFParser.prototype.parse = function ( onLoad, onError ) {
    
            var json = this.json;
            var parser = this;
    
            // Clear the loader cache
            this.cache.removeAll();
    
            // Mark the special nodes/meshes in json for efficient parse
            this.markDefs();
    
            // Fire the callback on complete
            this.getMultiDependencies( [
    
                'scene',
                'animation',
                'camera'
    
            ] ).then( function ( dependencies ) {
    
                var scenes = dependencies.scenes || [];
                var scene = scenes[ json.scene || 0 ];
                var animations = dependencies.animations || [];
                var asset = json.asset;
                var cameras = dependencies.cameras || [];
    
                onLoad( scene, scenes, cameras, animations, asset );
    
            } ).catch( onError );
    
        };
    
        /**
         * Marks the special nodes/meshes in json for efficient parse.
         */
        GLTFParser.prototype.markDefs = function () {
    
            var nodeDefs = this.json.nodes || [];
            var skinDefs = this.json.skins || [];
            var meshDefs = this.json.meshes || [];
    
            var meshReferences = {};
            var meshUses = {};
    
            // Nothing in the node definition indicates whether it is a Bone or an
            // Object3D. Use the skins' joint references to mark bones.
            for ( var skinIndex = 0, skinLength = skinDefs.length; skinIndex < skinLength; skinIndex ++ ) {
    
                var joints = skinDefs[ skinIndex ].joints;
    
                for ( var i = 0, il = joints.length; i < il; i ++ ) {
    
                    nodeDefs[ joints[ i ] ].isBone = true;
    
                }
    
            }
    
            // Meshes can (and should) be reused by multiple nodes in a glTF asset. To
            // avoid having more than one THREE.Mesh with the same name, count
            // references and rename instances below.
            //
            // Example: CesiumMilkTruck sample model reuses "Wheel" meshes.
            for ( var nodeIndex = 0, nodeLength = nodeDefs.length; nodeIndex < nodeLength; nodeIndex ++ ) {
    
                var nodeDef = nodeDefs[ nodeIndex ];
    
                if ( nodeDef.mesh !== undefined ) {
    
                    if ( meshReferences[ nodeDef.mesh ] === undefined ) {
    
                        meshReferences[ nodeDef.mesh ] = meshUses[ nodeDef.mesh ] = 0;
    
                    }
    
                    meshReferences[ nodeDef.mesh ] ++;
    
                    // Nothing in the mesh definition indicates whether it is
                    // a SkinnedMesh or Mesh. Use the node's mesh reference
                    // to mark SkinnedMesh if node has skin.
                    if ( nodeDef.skin !== undefined ) {
    
                        meshDefs[ nodeDef.mesh ].isSkinnedMesh = true;
    
                    }
    
                }
    
            }
    
            this.json.meshReferences = meshReferences;
            this.json.meshUses = meshUses;
    
        };
    
        /**
         * Requests the specified dependency asynchronously, with caching.
         * @param {string} type
         * @param {number} index
         * @return {Promise<Object>}
         */
        GLTFParser.prototype.getDependency = function ( type, index ) {
    
            var cacheKey = type + ':' + index;
            var dependency = this.cache.get( cacheKey );
    
            if ( ! dependency ) {
    
                var fnName = 'load' + type.charAt( 0 ).toUpperCase() + type.slice( 1 );
                dependency = this[ fnName ]( index );
                this.cache.add( cacheKey, dependency );
    
            }
    
            return dependency;
    
        };
    
        /**
         * Requests all dependencies of the specified type asynchronously, with caching.
         * @param {string} type
         * @return {Promise<Array<Object>>}
         */
        GLTFParser.prototype.getDependencies = function ( type ) {
    
            var dependencies = this.cache.get( type );
    
            if ( ! dependencies ) {
    
                var parser = this;
                var defs = this.json[ type + ( type === 'mesh' ? 'es' : 's' ) ] || [];
    
                dependencies = Promise.all( defs.map( function ( def, index ) {
    
                    return parser.getDependency( type, index );
    
                } ) );
    
                this.cache.add( type, dependencies );
    
            }
    
            return dependencies;
    
        };
    
        /**
         * Requests all multiple dependencies of the specified types asynchronously, with caching.
         * @param {Array<string>} types
         * @return {Promise<Object<Array<Object>>>}
         */
        GLTFParser.prototype.getMultiDependencies = function ( types ) {
    
            var results = {};
            var pendings = [];
    
            for ( var i = 0, il = types.length; i < il; i ++ ) {
    
                var type = types[ i ];
                var value = this.getDependencies( type );
    
                value = value.then( function ( key, value ) {
    
                    results[ key ] = value;
    
                }.bind( this, type + ( type === 'mesh' ? 'es' : 's' ) ) );
    
                pendings.push( value );
    
            }
    
            return Promise.all( pendings ).then( function () {
    
                return results;
    
            } );
    
        };
    
        /**
         * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#buffers-and-buffer-views
         * @param {number} bufferIndex
         * @return {Promise<ArrayBuffer>}
         */
        GLTFParser.prototype.loadBuffer = function ( bufferIndex ) {
    
            var bufferDef = this.json.buffers[ bufferIndex ];
            var loader = this.fileLoader;
    
            if ( bufferDef.type && bufferDef.type !== 'arraybuffer' ) {
    
                throw new Error( 'THREE.GLTFLoader: ' + bufferDef.type + ' buffer type is not supported.' );
    
            }
    
            // If present, GLB container is required to be the first buffer.
            if ( bufferDef.uri === undefined && bufferIndex === 0 ) {
    
                return Promise.resolve( this.extensions[ EXTENSIONS.KHR_BINARY_GLTF ].body );
    
            }
    
            var options = this.options;
    
            return new Promise( function ( resolve, reject ) {
    
                loader.load( resolveURL( bufferDef.uri, options.path ), resolve, undefined, function () {
    
                    reject( new Error( 'THREE.GLTFLoader: Failed to load buffer "' + bufferDef.uri + '".' ) );
    
                } );
    
            } );
    
        };
    
        /**
         * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#buffers-and-buffer-views
         * @param {number} bufferViewIndex
         * @return {Promise<ArrayBuffer>}
         */
        GLTFParser.prototype.loadBufferView = function ( bufferViewIndex ) {
    
            var bufferViewDef = this.json.bufferViews[ bufferViewIndex ];
    
            return this.getDependency( 'buffer', bufferViewDef.buffer ).then( function ( buffer ) {
    
                var byteLength = bufferViewDef.byteLength || 0;
                var byteOffset = bufferViewDef.byteOffset || 0;
                return buffer.slice( byteOffset, byteOffset + byteLength );
    
            } );
    
        };
    
        /**
         * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#accessors
         * @param {number} accessorIndex
         * @return {Promise<THREE.BufferAttribute|THREE.InterleavedBufferAttribute>}
         */
        GLTFParser.prototype.loadAccessor = function ( accessorIndex ) {
    
            var json = this.json;
    
            var accessorDef = this.json.accessors[ accessorIndex ];
    
            var pendingBufferViews = [];
    
            if ( accessorDef.bufferView !== undefined ) {
    
                pendingBufferViews.push( this.getDependency( 'bufferView', accessorDef.bufferView ) );
    
            } else {
    
                pendingBufferViews.push( null );
    
            }
    
            if ( accessorDef.sparse !== undefined ) {
    
                pendingBufferViews.push( this.getDependency( 'bufferView', accessorDef.sparse.indices.bufferView ) );
                pendingBufferViews.push( this.getDependency( 'bufferView', accessorDef.sparse.values.bufferView ) );
    
            }
    
            return Promise.all( pendingBufferViews ).then( function ( bufferViews ) {
    
                var bufferView = bufferViews[ 0 ];
    
                var itemSize = WEBGL_TYPE_SIZES[ accessorDef.type ];
                var TypedArray = WEBGL_COMPONENT_TYPES[ accessorDef.componentType ];
    
                // For VEC3: itemSize is 3, elementBytes is 4, itemBytes is 12.
                var elementBytes = TypedArray.BYTES_PER_ELEMENT;
                var itemBytes = elementBytes * itemSize;
                var byteStride = json.bufferViews[ accessorDef.bufferView ].byteStride;
                var normalized = accessorDef.normalized === true;
                var array, bufferAttribute;
    
                // The buffer is not interleaved if the stride is the item size in bytes.
                if ( byteStride && byteStride !== itemBytes ) {
    
                    // Use the full buffer if it's interleaved.
                    array = new TypedArray( bufferView );
    
                    // Integer parameters to IB/IBA are in array elements, not bytes.
                    var ib = new THREE.InterleavedBuffer( array, byteStride / elementBytes );
    
                    bufferAttribute = new THREE.InterleavedBufferAttribute( ib, itemSize, accessorDef.byteOffset / elementBytes, normalized );
    
                } else {
    
                    if ( bufferView === null ) {
    
                        array = new TypedArray( accessorDef.count * itemSize );
    
                    } else {
    
                        array = new TypedArray( bufferView, accessorDef.byteOffset, accessorDef.count * itemSize );
    
                    }
    
                    bufferAttribute = new THREE.BufferAttribute( array, itemSize, normalized );
    
                }
    
                // https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#sparse-accessors
                if ( accessorDef.sparse !== undefined ) {
    
                    var itemSizeIndices = WEBGL_TYPE_SIZES.SCALAR;
                    var TypedArrayIndices = WEBGL_COMPONENT_TYPES[ accessorDef.sparse.indices.componentType ];
    
                    var byteOffsetIndices = accessorDef.sparse.indices.byteOffset || 0;
                    var byteOffsetValues = accessorDef.sparse.values.byteOffset || 0;
    
                    var sparseIndices = new TypedArrayIndices( bufferViews[ 1 ], byteOffsetIndices, accessorDef.sparse.count * itemSizeIndices );
                    var sparseValues = new TypedArray( bufferViews[ 2 ], byteOffsetValues, accessorDef.sparse.count * itemSize );
    
                    if ( bufferView !== null ) {
    
                        // Avoid modifying the original ArrayBuffer, if the bufferView wasn't initialized with zeroes.
                        bufferAttribute.setArray( bufferAttribute.array.slice() );
    
                    }
    
                    for ( var i = 0, il = sparseIndices.length; i < il; i ++ ) {
    
                        var index = sparseIndices[ i ];
    
                        bufferAttribute.setX( index, sparseValues[ i * itemSize ] );
                        if ( itemSize >= 2 ) bufferAttribute.setY( index, sparseValues[ i * itemSize + 1 ] );
                        if ( itemSize >= 3 ) bufferAttribute.setZ( index, sparseValues[ i * itemSize + 2 ] );
                        if ( itemSize >= 4 ) bufferAttribute.setW( index, sparseValues[ i * itemSize + 3 ] );
                        if ( itemSize >= 5 ) throw new Error( 'THREE.GLTFLoader: Unsupported itemSize in sparse BufferAttribute.' );
    
                    }
    
                }
    
                return bufferAttribute;
    
            } );
    
        };
    
        /**
         * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#textures
         * @param {number} textureIndex
         * @return {Promise<THREE.Texture>}
         */
        GLTFParser.prototype.loadTexture = function ( textureIndex ) {
    
            var parser = this;
            var json = this.json;
            var options = this.options;
            var textureLoader = this.textureLoader;
    
            var URL = window.URL || window.webkitURL;
    
            var textureDef = json.textures[ textureIndex ];
            var source = json.images[ textureDef.source ];
            var sourceURI = source.uri;
            var isObjectURL = false;
    
            if ( source.bufferView !== undefined ) {
    
                // Load binary image data from bufferView, if provided.
    
                sourceURI = parser.getDependency( 'bufferView', source.bufferView ).then( function ( bufferView ) {
    
                    isObjectURL = true;
                    var blob = new Blob( [ bufferView ], { type: source.mimeType } );
                    sourceURI = URL.createObjectURL( blob );
                    return sourceURI;
    
                } );
    
            }
    
            return Promise.resolve( sourceURI ).then( function ( sourceURI ) {
    
                // Load Texture resource.
    
                var loader = THREE.Loader.Handlers.get( sourceURI ) || textureLoader;
    
                return new Promise( function ( resolve, reject ) {
    
                    loader.load( resolveURL( sourceURI, options.path ), resolve, undefined, reject );
    
                } );
    
            } ).then( function ( texture ) {
    
                // Clean up resources and configure Texture.
    
                if ( isObjectURL === true ) {
    
                    URL.revokeObjectURL( sourceURI );
    
                }
    
                texture.flipY = false;
    
                if ( textureDef.name !== undefined ) texture.name = textureDef.name;
    
                texture.format = textureDef.format !== undefined ? WEBGL_TEXTURE_FORMATS[ textureDef.format ] : THREE.RGBAFormat;
    
                if ( textureDef.internalFormat !== undefined && texture.format !== WEBGL_TEXTURE_FORMATS[ textureDef.internalFormat ] ) {
    
                    console.warn( 'THREE.GLTFLoader: Three.js does not support texture internalFormat which is different from texture format. ' +
                                                'internalFormat will be forced to be the same value as format.' );
    
                }
    
                texture.type = textureDef.type !== undefined ? WEBGL_TEXTURE_DATATYPES[ textureDef.type ] : THREE.UnsignedByteType;
    
                var samplers = json.samplers || {};
                var sampler = samplers[ textureDef.sampler ] || {};
    
                texture.magFilter = WEBGL_FILTERS[ sampler.magFilter ] || THREE.LinearFilter;
                texture.minFilter = WEBGL_FILTERS[ sampler.minFilter ] || THREE.LinearMipMapLinearFilter;
                texture.wrapS = WEBGL_WRAPPINGS[ sampler.wrapS ] || THREE.RepeatWrapping;
                texture.wrapT = WEBGL_WRAPPINGS[ sampler.wrapT ] || THREE.RepeatWrapping;
    
                return texture;
    
            } );
    
        };
    
        /**
         * Asynchronously assigns a texture to the given material parameters.
         * @param {Object} materialParams
         * @param {string} textureName
         * @param {number} textureIndex
         * @return {Promise}
         */
        GLTFParser.prototype.assignTexture = function ( materialParams, textureName, textureIndex ) {
    
            return this.getDependency( 'texture', textureIndex ).then( function ( texture ) {
    
                materialParams[ textureName ] = texture;
    
            } );
    
        };
    
        /**
         * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#materials
         * @param {number} materialIndex
         * @return {Promise<THREE.Material>}
         */
        GLTFParser.prototype.loadMaterial = function ( materialIndex ) {
    
            var parser = this;
            var json = this.json;
            var extensions = this.extensions;
            var materialDef = this.json.materials[ materialIndex ];
    
            var materialType;
            var materialParams = {};
            var materialExtensions = materialDef.extensions || {};
    
            var pending = [];
    
            if ( materialExtensions[ EXTENSIONS.KHR_MATERIALS_COMMON ] ) {
    
                var khcExtension = extensions[ EXTENSIONS.KHR_MATERIALS_COMMON ];
                materialType = khcExtension.getMaterialType( materialDef );
                pending.push( khcExtension.extendParams( materialParams, materialDef, parser ) );
    
            } else if ( materialExtensions[ EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS ] ) {
    
                var sgExtension = extensions[ EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS ];
                materialType = sgExtension.getMaterialType( materialDef );
                pending.push( sgExtension.extendParams( materialParams, materialDef, parser ) );
    
            } else if ( materialDef.pbrMetallicRoughness !== undefined ) {
    
                // Specification:
                // https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#metallic-roughness-material
    
                materialType = THREE.MeshStandardMaterial;
    
                var metallicRoughness = materialDef.pbrMetallicRoughness;
    
                materialParams.color = new THREE.Color( 1.0, 1.0, 1.0 );
                materialParams.opacity = 1.0;
    
                if ( Array.isArray( metallicRoughness.baseColorFactor ) ) {
    
                    var array = metallicRoughness.baseColorFactor;
    
                    materialParams.color.fromArray( array );
                    materialParams.opacity = array[ 3 ];
    
                }
    
                if ( metallicRoughness.baseColorTexture !== undefined ) {
    
                    pending.push( parser.assignTexture( materialParams, 'map', metallicRoughness.baseColorTexture.index ) );
    
                }
    
                materialParams.metalness = metallicRoughness.metallicFactor !== undefined ? metallicRoughness.metallicFactor : 1.0;
                materialParams.roughness = metallicRoughness.roughnessFactor !== undefined ? metallicRoughness.roughnessFactor : 1.0;
    
                if ( metallicRoughness.metallicRoughnessTexture !== undefined ) {
    
                    var textureIndex = metallicRoughness.metallicRoughnessTexture.index;
                    pending.push( parser.assignTexture( materialParams, 'metalnessMap', textureIndex ) );
                    pending.push( parser.assignTexture( materialParams, 'roughnessMap', textureIndex ) );
    
                }
    
            } else {
    
                materialType = THREE.MeshPhongMaterial;
    
            }
    
            if ( materialDef.doubleSided === true ) {
    
                materialParams.side = THREE.DoubleSide;
    
            }
    
            var alphaMode = materialDef.alphaMode || ALPHA_MODES.OPAQUE;
    
            if ( alphaMode === ALPHA_MODES.BLEND ) {
    
                materialParams.transparent = true;
    
            } else {
    
                materialParams.transparent = false;
    
                if ( alphaMode === ALPHA_MODES.MASK ) {
    
                    materialParams.alphaTest = materialDef.alphaCutoff !== undefined ? materialDef.alphaCutoff : 0.5;
    
                }
    
            }
    
            if ( materialDef.normalTexture !== undefined ) {
    
                pending.push( parser.assignTexture( materialParams, 'normalMap', materialDef.normalTexture.index ) );
    
                materialParams.normalScale = new THREE.Vector2( 1, 1 );
    
                if ( materialDef.normalTexture.scale !== undefined ) {
    
                    materialParams.normalScale.set( materialDef.normalTexture.scale, materialDef.normalTexture.scale );
    
                }
    
            }
    
            if ( materialDef.occlusionTexture !== undefined ) {
    
                pending.push( parser.assignTexture( materialParams, 'aoMap', materialDef.occlusionTexture.index ) );
    
                if ( materialDef.occlusionTexture.strength !== undefined ) {
    
                    materialParams.aoMapIntensity = materialDef.occlusionTexture.strength;
    
                }
    
            }
    
            if ( materialDef.emissiveFactor !== undefined ) {
    
                if ( materialType === THREE.MeshBasicMaterial ) {
    
                    materialParams.color = new THREE.Color().fromArray( materialDef.emissiveFactor );
    
                } else {
    
                    materialParams.emissive = new THREE.Color().fromArray( materialDef.emissiveFactor );
    
                }
    
            }
    
            if ( materialDef.emissiveTexture !== undefined ) {
    
                if ( materialType === THREE.MeshBasicMaterial ) {
    
                    pending.push( parser.assignTexture( materialParams, 'map', materialDef.emissiveTexture.index ) );
    
                } else {
    
                    pending.push( parser.assignTexture( materialParams, 'emissiveMap', materialDef.emissiveTexture.index ) );
    
                }
    
            }
    
            return Promise.all( pending ).then( function () {
    
                var material;
    
                if ( materialType === THREE.ShaderMaterial ) {
    
                    material = extensions[ EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS ].createMaterial( materialParams );
    
                } else {
    
                    material = new materialType( materialParams );
    
                }
    
                if ( materialDef.name !== undefined ) material.name = materialDef.name;
    
                // Normal map textures use OpenGL conventions:
                // https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#materialnormaltexture
                if ( material.normalScale ) {
    
                    material.normalScale.x = - material.normalScale.x;
    
                }
    
                // emissiveTexture and baseColorTexture use sRGB encoding.
                if ( material.map ) material.map.encoding = THREE.sRGBEncoding;
                if ( material.emissiveMap ) material.emissiveMap.encoding = THREE.sRGBEncoding;
    
                if ( materialDef.extras ) material.userData = materialDef.extras;
    
                return material;
    
            } );
    
        };
    
        /**
         * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#geometry
         * @param {Array<Object>} primitives
         * @return {Promise<Array<THREE.BufferGeometry>>}
         */
        GLTFParser.prototype.loadGeometries = function ( primitives ) {
    
            var cache = this.primitiveCache;
    
            return this.getDependencies( 'accessor' ).then( function ( accessors ) {
    
                var geometries = [];
    
                for ( var i = 0, il = primitives.length; i < il; i ++ ) {
    
                    var primitive = primitives[ i ];
    
                    // See if we've already created this geometry
                    var cached = getCachedGeometry( cache, primitive );
    
                    if ( cached ) {
    
                        // Use the cached geometry if it exists
                        geometries.push( cached );
    
                    } else {
    
                        // Otherwise create a new geometry
                        var geometry = new THREE.BufferGeometry();
    
                        var attributes = primitive.attributes;
    
                        for ( var attributeId in attributes ) {
    
                            var attributeEntry = attributes[ attributeId ];
    
                            var bufferAttribute = accessors[ attributeEntry ];
    
                            switch ( attributeId ) {
    
                                case 'POSITION':
    
                                    geometry.addAttribute( 'position', bufferAttribute );
                                    break;
    
                                case 'NORMAL':
    
                                    geometry.addAttribute( 'normal', bufferAttribute );
                                    break;
    
                                case 'TEXCOORD_0':
                                case 'TEXCOORD0':
                                case 'TEXCOORD':
    
                                    geometry.addAttribute( 'uv', bufferAttribute );
                                    break;
    
                                case 'TEXCOORD_1':
    
                                    geometry.addAttribute( 'uv2', bufferAttribute );
                                    break;
    
                                case 'COLOR_0':
                                case 'COLOR0':
                                case 'COLOR':
    
                                    geometry.addAttribute( 'color', bufferAttribute );
                                    break;
    
                                case 'WEIGHTS_0':
                                case 'WEIGHT': // WEIGHT semantic deprecated.
    
                                    geometry.addAttribute( 'skinWeight', bufferAttribute );
                                    break;
    
                                case 'JOINTS_0':
                                case 'JOINT': // JOINT semantic deprecated.
    
                                    geometry.addAttribute( 'skinIndex', bufferAttribute );
                                    break;
    
                            }
    
                        }
    
                        if ( primitive.indices !== undefined ) {
    
                            geometry.setIndex( accessors[ primitive.indices ] );
    
                        }
    
                        // Cache this geometry
                        cache.push( {
    
                            primitive: primitive,
                            geometry: geometry
    
                        } );
    
                        geometries.push( geometry );
    
                    }
    
                }
    
                return geometries;
    
            } );
    
        };
    
        /**
         * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#meshes
         * @param {number} meshIndex
         * @return {Promise<THREE.Group|THREE.Mesh|THREE.SkinnedMesh>}
         */
        GLTFParser.prototype.loadMesh = function ( meshIndex ) {
    
            var scope = this;
            var json = this.json;
            var extensions = this.extensions;
    
            var meshDef = this.json.meshes[ meshIndex ];
    
            return this.getMultiDependencies( [
    
                'accessor',
                'material'
    
            ] ).then( function ( dependencies ) {
    
                var group = new THREE.Group();
    
                var primitives = meshDef.primitives;
    
                return scope.loadGeometries( primitives ).then( function ( geometries ) {
    
                    for ( var i = 0, il = primitives.length; i < il; i ++ ) {
    
                        var primitive = primitives[ i ];
                        var geometry = geometries[ i ];
    
                        var material = primitive.material === undefined
                            ? createDefaultMaterial()
                            : dependencies.materials[ primitive.material ];
    
                        if ( material.aoMap
                                && geometry.attributes.uv2 === undefined
                                && geometry.attributes.uv !== undefined ) {
    
                            console.log( 'THREE.GLTFLoader: Duplicating UVs to support aoMap.' );
                            geometry.addAttribute( 'uv2', new THREE.BufferAttribute( geometry.attributes.uv.array, 2 ) );
    
                        }
    
                        // If the material will be modified later on, clone it now.
                        var useVertexColors = geometry.attributes.color !== undefined;
                        var useFlatShading = geometry.attributes.normal === undefined;
                        var useSkinning = meshDef.isSkinnedMesh === true;
                        var useMorphTargets = primitive.targets !== undefined;
    
                        if ( useVertexColors || useFlatShading || useSkinning || useMorphTargets ) {
    
                            if ( material.isGLTFSpecularGlossinessMaterial ) {
    
                                var specGlossExtension = extensions[ EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS ];
                                material = specGlossExtension.cloneMaterial( material );
    
                            } else {
    
                                material = material.clone();
    
                            }
    
                        }
    
                        if ( useVertexColors ) {
    
                            material.vertexColors = THREE.VertexColors;
                            material.needsUpdate = true;
    
                        }
    
                        if ( useFlatShading ) {
    
                            material.flatShading = true;
    
                        }
    
                        var mesh;
    
                        if ( primitive.mode === WEBGL_CONSTANTS.TRIANGLES ||
                            primitive.mode === WEBGL_CONSTANTS.TRIANGLE_STRIP ||
                            primitive.mode === WEBGL_CONSTANTS.TRIANGLE_FAN ||
                            primitive.mode === undefined ) {
    
                            if ( useSkinning ) {
    
                                mesh = new THREE.SkinnedMesh( geometry, material );
                                material.skinning = true;
    
                            } else {
    
                                mesh = new THREE.Mesh( geometry, material );
    
                            }
    
                            if ( primitive.mode === WEBGL_CONSTANTS.TRIANGLE_STRIP ) {
    
                                mesh.drawMode = THREE.TriangleStripDrawMode;
    
                            } else if ( primitive.mode === WEBGL_CONSTANTS.TRIANGLE_FAN ) {
    
                                mesh.drawMode = THREE.TriangleFanDrawMode;
    
                            }
    
                        } else if ( primitive.mode === WEBGL_CONSTANTS.LINES ) {
    
                            mesh = new THREE.LineSegments( geometry, material );
    
                        } else if ( primitive.mode === WEBGL_CONSTANTS.LINE_STRIP ) {
    
                            mesh = new THREE.Line( geometry, material );
    
                        } else if ( primitive.mode === WEBGL_CONSTANTS.LINE_LOOP ) {
    
                            mesh = new THREE.LineLoop( geometry, material );
    
                        } else if ( primitive.mode === WEBGL_CONSTANTS.POINTS ) {
    
                            mesh = new THREE.Points( geometry, material );
    
                        } else {
    
                            throw new Error( 'THREE.GLTFLoader: Primitive mode unsupported: ' + primitive.mode );
    
                        }
    
                        mesh.name = meshDef.name || ( 'mesh_' + meshIndex );
    
                        if ( useMorphTargets ) {
    
                            addMorphTargets( mesh, meshDef, primitive, dependencies.accessors );
    
                        }
    
                        if ( meshDef.extras !== undefined ) mesh.userData = meshDef.extras;
                        if ( primitive.extras !== undefined ) mesh.geometry.userData = primitive.extras;
    
                        // for Specular-Glossiness.
                        if ( material.isGLTFSpecularGlossinessMaterial === true ) {
    
                            mesh.onBeforeRender = extensions[ EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS ].refreshUniforms;
    
                        }
    
                        if ( primitives.length > 1 ) {
    
                            mesh.name += '_' + i;
    
                            group.add( mesh );
    
                        } else {
    
                            return mesh;
    
                        }
    
                    }
    
                    return group;
    
                } );
    
            } );
    
        };
    
        /**
         * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#cameras
         * @param {number} cameraIndex
         * @return {Promise<THREE.Camera>}
         */
        GLTFParser.prototype.loadCamera = function ( cameraIndex ) {
    
            var camera;
            var cameraDef = this.json.cameras[ cameraIndex ];
            var params = cameraDef[ cameraDef.type ];
    
            if ( ! params ) {
    
                console.warn( 'THREE.GLTFLoader: Missing camera parameters.' );
                return;
    
            }
    
            if ( cameraDef.type === 'perspective' ) {
    
                var aspectRatio = params.aspectRatio || 1;
                var xfov = params.yfov * aspectRatio;
    
                camera = new THREE.PerspectiveCamera( THREE.Math.radToDeg( xfov ), aspectRatio, params.znear || 1, params.zfar || 2e6 );
    
            } else if ( cameraDef.type === 'orthographic' ) {
    
                camera = new THREE.OrthographicCamera( params.xmag / - 2, params.xmag / 2, params.ymag / 2, params.ymag / - 2, params.znear, params.zfar );
    
            }
    
            if ( cameraDef.name !== undefined ) camera.name = cameraDef.name;
            if ( cameraDef.extras ) camera.userData = cameraDef.extras;
    
            return Promise.resolve( camera );
    
        };
    
        /**
         * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#skins
         * @param {number} skinIndex
         * @return {Promise<Object>}
         */
        GLTFParser.prototype.loadSkin = function ( skinIndex ) {
    
            var skinDef = this.json.skins[ skinIndex ];
    
            var skinEntry = { joints: skinDef.joints };
    
            if ( skinDef.inverseBindMatrices === undefined ) {
    
                return Promise.resolve( skinEntry );
    
            }
    
            return this.getDependency( 'accessor', skinDef.inverseBindMatrices ).then( function ( accessor ) {
    
                skinEntry.inverseBindMatrices = accessor;
    
                return skinEntry;
    
            } );
    
        };
    
        /**
         * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#animations
         * @param {number} animationIndex
         * @return {Promise<THREE.AnimationClip>}
         */
        GLTFParser.prototype.loadAnimation = function ( animationIndex ) {
    
            var json = this.json;
    
            var animationDef = this.json.animations[ animationIndex ];
    
            return this.getMultiDependencies( [
    
                'accessor',
                'node'
    
            ] ).then( function ( dependencies ) {
    
                var tracks = [];
    
                for ( var i = 0, il = animationDef.channels.length; i < il; i ++ ) {
    
                    var channel = animationDef.channels[ i ];
                    var sampler = animationDef.samplers[ channel.sampler ];
    
                    if ( sampler ) {
    
                        var target = channel.target;
                        var name = target.node !== undefined ? target.node : target.id; // NOTE: target.id is deprecated.
                        var input = animationDef.parameters !== undefined ? animationDef.parameters[ sampler.input ] : sampler.input;
                        var output = animationDef.parameters !== undefined ? animationDef.parameters[ sampler.output ] : sampler.output;
    
                        var inputAccessor = dependencies.accessors[ input ];
                        var outputAccessor = dependencies.accessors[ output ];
    
                        var node = dependencies.nodes[ name ];
    
                        if ( node ) {
    
                            node.updateMatrix();
                            node.matrixAutoUpdate = true;
    
                            var TypedKeyframeTrack;
    
                            switch ( PATH_PROPERTIES[ target.path ] ) {
    
                                case PATH_PROPERTIES.weights:
    
                                    TypedKeyframeTrack = THREE.NumberKeyframeTrack;
                                    break;
    
                                case PATH_PROPERTIES.rotation:
    
                                    TypedKeyframeTrack = THREE.QuaternionKeyframeTrack;
                                    break;
    
                                case PATH_PROPERTIES.position:
                                case PATH_PROPERTIES.scale:
                                default:
    
                                    TypedKeyframeTrack = THREE.VectorKeyframeTrack;
                                    break;
    
                            }
    
                            var targetName = node.name ? node.name : node.uuid;
    
                            if ( sampler.interpolation === 'CUBICSPLINE' ) {
    
                                var itemSize = outputAccessor.itemSize;
                                var TypedArray = outputAccessor.array.constructor;
                                var outputAccessorValues = new TypedArray( outputAccessor.count * itemSize / 3 );
    
                                // Layout of keyframe output values for CUBICSPLINE animations:
                                //
                                //   [ inTangent1, splineVertex1, outTangent1, inTangent2, splineVertex2, ... ]
                                //
                                // THREE.KeyframeTrack infers tangents from the spline vertices when interpolating:
                                // those values are extracted below. This still guarantees smooth curves, but does
                                // throw away more precise information in the tangents. In the future, consider
                                // re-sampling at a higher framerate using the tangents provided.
                                //
                                // See: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#appendix-c-spline-interpolation
    
                                for ( var j = 0, jl = outputAccessor.count; j < jl; j += 3 ) {
    
                                    outputAccessorValues[ j * itemSize / 3 ] = outputAccessor.getX( j + 1 );
                                    if ( itemSize > 1 ) outputAccessorValues[ j * itemSize / 3 + 1 ] = outputAccessor.getY( j + 1 );
                                    if ( itemSize > 2 ) outputAccessorValues[ j * itemSize / 3 + 2 ] = outputAccessor.getZ( j + 1 );
                                    if ( itemSize > 3 ) outputAccessorValues[ j * itemSize / 3 + 3 ] = outputAccessor.getW( j + 1 );
    
                                }
    
                                outputAccessor = new THREE.BufferAttribute( outputAccessorValues, itemSize / 3, outputAccessor.normalized );
    
                            }
    
                            var interpolation = sampler.interpolation !== undefined ? INTERPOLATION[ sampler.interpolation ] : THREE.InterpolateLinear;
    
                            var targetNames = [];
    
                            if ( PATH_PROPERTIES[ target.path ] === PATH_PROPERTIES.weights ) {
    
                                // node should be THREE.Group here but
                                // PATH_PROPERTIES.weights(morphTargetInfluences) should be
                                // the property of a mesh object under node.
                                // So finding targets here.
    
                                node.traverse( function ( object ) {
    
                                    if ( object.isMesh === true && object.material.morphTargets === true ) {
    
                                        targetNames.push( object.name ? object.name : object.uuid );
    
                                    }
    
                                } );
    
                            } else {
    
                                targetNames.push( targetName );
    
                            }
    
                            // KeyframeTrack.optimize() will modify given 'times' and 'values'
                            // buffers before creating a truncated copy to keep. Because buffers may
                            // be reused by other tracks, make copies here.
                            for ( var j = 0, jl = targetNames.length; j < jl; j ++ ) {
    
                                tracks.push( new TypedKeyframeTrack(
                                    targetNames[ j ] + '.' + PATH_PROPERTIES[ target.path ],
                                    THREE.AnimationUtils.arraySlice( inputAccessor.array, 0 ),
                                    THREE.AnimationUtils.arraySlice( outputAccessor.array, 0 ),
                                    interpolation
                                ) );
    
                            }
    
                        }
    
                    }
    
                }
    
                var name = animationDef.name !== undefined ? animationDef.name : 'animation_' + animationIndex;
    
                return new THREE.AnimationClip( name, undefined, tracks );
    
            } );
    
        };
    
        /**
         * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#nodes-and-hierarchy
         * @param {number} nodeIndex
         * @return {Promise<THREE.Object3D>}
         */
        GLTFParser.prototype.loadNode = function ( nodeIndex ) {
    
            var json = this.json;
            var extensions = this.extensions;
    
            var meshReferences = this.json.meshReferences;
            var meshUses = this.json.meshUses;
    
            var nodeDef = this.json.nodes[ nodeIndex ];
    
            return this.getMultiDependencies( [
    
                'mesh',
                'skin',
                'camera'
    
            ] ).then( function ( dependencies ) {
    
                var node;
    
                if ( nodeDef.isBone === true ) {
    
                    node = new THREE.Bone();
    
                } else if ( nodeDef.mesh !== undefined ) {
    
                    var mesh = dependencies.meshes[ nodeDef.mesh ];
    
                    node = mesh.clone();
    
                    // for Specular-Glossiness
                    if ( mesh.isGroup === true ) {
    
                        for ( var i = 0, il = mesh.children.length; i < il; i ++ ) {
    
                            var child = mesh.children[ i ];
    
                            if ( child.material && child.material.isGLTFSpecularGlossinessMaterial === true ) {
    
                                node.children[ i ].onBeforeRender = child.onBeforeRender;
    
                            }
    
                        }
    
                    } else {
    
                        if ( mesh.material && mesh.material.isGLTFSpecularGlossinessMaterial === true ) {
    
                            node.onBeforeRender = mesh.onBeforeRender;
    
                        }
    
                    }
    
                    if ( meshReferences[ nodeDef.mesh ] > 1 ) {
    
                        node.name += '_instance_' + meshUses[ nodeDef.mesh ] ++;
    
                    }
    
                } else if ( nodeDef.camera !== undefined ) {
    
                    node = dependencies.cameras[ nodeDef.camera ];
    
                } else if ( nodeDef.extensions
                         && nodeDef.extensions[ EXTENSIONS.KHR_LIGHTS ]
                         && nodeDef.extensions[ EXTENSIONS.KHR_LIGHTS ].light !== undefined ) {
    
                    var lights = extensions[ EXTENSIONS.KHR_LIGHTS ].lights;
                    node = lights[ nodeDef.extensions[ EXTENSIONS.KHR_LIGHTS ].light ];
    
                } else {
    
                    node = new THREE.Object3D();
    
                }
    
                if ( nodeDef.name !== undefined ) {
    
                    node.name = THREE.PropertyBinding.sanitizeNodeName( nodeDef.name );
    
                }
    
                if ( nodeDef.extras ) node.userData = nodeDef.extras;
    
                if ( nodeDef.matrix !== undefined ) {
    
                    var matrix = new THREE.Matrix4();
                    matrix.fromArray( nodeDef.matrix );
                    node.applyMatrix( matrix );
    
                } else {
    
                    if ( nodeDef.translation !== undefined ) {
    
                        node.position.fromArray( nodeDef.translation );
    
                    }
    
                    if ( nodeDef.rotation !== undefined ) {
    
                        node.quaternion.fromArray( nodeDef.rotation );
    
                    }
    
                    if ( nodeDef.scale !== undefined ) {
    
                        node.scale.fromArray( nodeDef.scale );
    
                    }
    
                }
    
                return node;
    
            } );
    
        };
    
        /**
         * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#scenes
         * @param {number} sceneIndex
         * @return {Promise<THREE.Scene>}
         */
        GLTFParser.prototype.loadScene = function () {
    
            // scene node hierachy builder
    
            function buildNodeHierachy( nodeId, parentObject, json, allNodes, skins ) {
    
                var node = allNodes[ nodeId ];
                var nodeDef = json.nodes[ nodeId ];
    
                // build skeleton here as well
    
                if ( nodeDef.skin !== undefined ) {
    
                    var meshes = node.isGroup === true ? node.children : [ node ];
    
                    for ( var i = 0, il = meshes.length; i < il; i ++ ) {
    
                        var mesh = meshes[ i ];
                        var skinEntry = skins[ nodeDef.skin ];
    
                        var bones = [];
                        var boneInverses = [];
    
                        for ( var j = 0, jl = skinEntry.joints.length; j < jl; j ++ ) {
    
                            var jointId = skinEntry.joints[ j ];
                            var jointNode = allNodes[ jointId ];
    
                            if ( jointNode ) {
    
                                bones.push( jointNode );
    
                                var mat = new THREE.Matrix4();
    
                                if ( skinEntry.inverseBindMatrices !== undefined ) {
    
                                    mat.fromArray( skinEntry.inverseBindMatrices.array, j * 16 );
    
                                }
    
                                boneInverses.push( mat );
    
                            } else {
    
                                console.warn( 'THREE.GLTFLoader: Joint "%s" could not be found.', jointId );
    
                            }
    
                        }
    
                        mesh.bind( new THREE.Skeleton( bones, boneInverses ), mesh.matrixWorld );
    
                    }
    
                }
    
                // build node hierachy
    
                parentObject.add( node );
    
                if ( nodeDef.children ) {
    
                    var children = nodeDef.children;
    
                    for ( var i = 0, il = children.length; i < il; i ++ ) {
    
                        var child = children[ i ];
                        buildNodeHierachy( child, node, json, allNodes, skins );
    
                    }
    
                }
    
            }
    
            return function loadScene( sceneIndex ) {
    
                var json = this.json;
                var extensions = this.extensions;
                var sceneDef = this.json.scenes[ sceneIndex ];
    
                return this.getMultiDependencies( [
    
                    'node',
                    'skin'
    
                ] ).then( function ( dependencies ) {
    
                    var scene = new THREE.Scene();
                    if ( sceneDef.name !== undefined ) scene.name = sceneDef.name;
    
                    if ( sceneDef.extras ) scene.userData = sceneDef.extras;
    
                    var nodeIds = sceneDef.nodes || [];
    
                    for ( var i = 0, il = nodeIds.length; i < il; i ++ ) {
    
                        buildNodeHierachy( nodeIds[ i ], scene, json, dependencies.nodes, dependencies.skins );
    
                    }
    
                    // Ambient lighting, if present, is always attached to the scene root.
                    if ( sceneDef.extensions
                             && sceneDef.extensions[ EXTENSIONS.KHR_LIGHTS ]
                             && sceneDef.extensions[ EXTENSIONS.KHR_LIGHTS ].light !== undefined ) {
    
                        var lights = extensions[ EXTENSIONS.KHR_LIGHTS ].lights;
                        scene.add( lights[ sceneDef.extensions[ EXTENSIONS.KHR_LIGHTS ].light ] );
    
                    }
    
                    return scene;
    
                } );
    
            };
    
        }();
    
        return GLTFLoader;
    
    } )();