(function (global, factory) {
  if (typeof define === "function" && define.amd) {
    define(["exports", "three"], factory);
  } else if (typeof exports !== "undefined") {
    factory(exports, require("three"));
  } else {
    var mod = {
      exports: {}
    };
    factory(mod.exports, global.three);
    global.GLTFLoader = mod.exports;
  }
})(typeof globalThis !== "undefined" ? globalThis : typeof self !== "undefined" ? self : this, function (_exports, _three) {
  "use strict";

  Object.defineProperty(_exports, "__esModule", {
    value: true
  });
  _exports.GLTFLoader = void 0;

  function _slicedToArray(arr, i) { return _arrayWithHoles(arr) || _iterableToArrayLimit(arr, i) || _unsupportedIterableToArray(arr, i) || _nonIterableRest(); }

  function _nonIterableRest() { throw new TypeError("Invalid attempt to destructure non-iterable instance.\nIn order to be iterable, non-array objects must have a [Symbol.iterator]() method."); }

  function _iterableToArrayLimit(arr, i) { var _i = arr == null ? null : typeof Symbol !== "undefined" && arr[Symbol.iterator] || arr["@@iterator"]; if (_i == null) return; var _arr = []; var _n = true; var _d = false; var _s, _e; try { for (_i = _i.call(arr); !(_n = (_s = _i.next()).done); _n = true) { _arr.push(_s.value); if (i && _arr.length === i) break; } } catch (err) { _d = true; _e = err; } finally { try { if (!_n && _i["return"] != null) _i["return"](); } finally { if (_d) throw _e; } } return _arr; }

  function _arrayWithHoles(arr) { if (Array.isArray(arr)) return arr; }

  function _createForOfIteratorHelper(o, allowArrayLike) { var it = typeof Symbol !== "undefined" && o[Symbol.iterator] || o["@@iterator"]; if (!it) { if (Array.isArray(o) || (it = _unsupportedIterableToArray(o)) || allowArrayLike && o && typeof o.length === "number") { if (it) o = it; var i = 0; var F = function F() {}; return { s: F, n: function n() { if (i >= o.length) return { done: true }; return { done: false, value: o[i++] }; }, e: function e(_e2) { throw _e2; }, f: F }; } throw new TypeError("Invalid attempt to iterate non-iterable instance.\nIn order to be iterable, non-array objects must have a [Symbol.iterator]() method."); } var normalCompletion = true, didErr = false, err; return { s: function s() { it = it.call(o); }, n: function n() { var step = it.next(); normalCompletion = step.done; return step; }, e: function e(_e3) { didErr = true; err = _e3; }, f: function f() { try { if (!normalCompletion && it.return != null) it.return(); } finally { if (didErr) throw err; } } }; }

  function _unsupportedIterableToArray(o, minLen) { if (!o) return; if (typeof o === "string") return _arrayLikeToArray(o, minLen); var n = Object.prototype.toString.call(o).slice(8, -1); if (n === "Object" && o.constructor) n = o.constructor.name; if (n === "Map" || n === "Set") return Array.from(o); if (n === "Arguments" || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, minLen); }

  function _arrayLikeToArray(arr, len) { if (len == null || len > arr.length) len = arr.length; for (var i = 0, arr2 = new Array(len); i < len; i++) { arr2[i] = arr[i]; } return arr2; }

  function _get() { if (typeof Reflect !== "undefined" && Reflect.get) { _get = Reflect.get; } else { _get = function _get(target, property, receiver) { var base = _superPropBase(target, property); if (!base) return; var desc = Object.getOwnPropertyDescriptor(base, property); if (desc.get) { return desc.get.call(arguments.length < 3 ? target : receiver); } return desc.value; }; } return _get.apply(this, arguments); }

  function _superPropBase(object, property) { while (!Object.prototype.hasOwnProperty.call(object, property)) { object = _getPrototypeOf(object); if (object === null) break; } return object; }

  function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

  function _defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } }

  function _createClass(Constructor, protoProps, staticProps) { if (protoProps) _defineProperties(Constructor.prototype, protoProps); if (staticProps) _defineProperties(Constructor, staticProps); Object.defineProperty(Constructor, "prototype", { writable: false }); return Constructor; }

  function _inherits(subClass, superClass) { if (typeof superClass !== "function" && superClass !== null) { throw new TypeError("Super expression must either be null or a function"); } Object.defineProperty(subClass, "prototype", { value: Object.create(superClass && superClass.prototype, { constructor: { value: subClass, writable: true, configurable: true } }), writable: false }); if (superClass) _setPrototypeOf(subClass, superClass); }

  function _setPrototypeOf(o, p) { _setPrototypeOf = Object.setPrototypeOf || function _setPrototypeOf(o, p) { o.__proto__ = p; return o; }; return _setPrototypeOf(o, p); }

  function _createSuper(Derived) { var hasNativeReflectConstruct = _isNativeReflectConstruct(); return function _createSuperInternal() { var Super = _getPrototypeOf(Derived), result; if (hasNativeReflectConstruct) { var NewTarget = _getPrototypeOf(this).constructor; result = Reflect.construct(Super, arguments, NewTarget); } else { result = Super.apply(this, arguments); } return _possibleConstructorReturn(this, result); }; }

  function _possibleConstructorReturn(self, call) { if (call && (typeof call === "object" || typeof call === "function")) { return call; } else if (call !== void 0) { throw new TypeError("Derived constructors may only return object or undefined"); } return _assertThisInitialized(self); }

  function _assertThisInitialized(self) { if (self === void 0) { throw new ReferenceError("this hasn't been initialised - super() hasn't been called"); } return self; }

  function _isNativeReflectConstruct() { if (typeof Reflect === "undefined" || !Reflect.construct) return false; if (Reflect.construct.sham) return false; if (typeof Proxy === "function") return true; try { Boolean.prototype.valueOf.call(Reflect.construct(Boolean, [], function () {})); return true; } catch (e) { return false; } }

  function _getPrototypeOf(o) { _getPrototypeOf = Object.setPrototypeOf ? Object.getPrototypeOf : function _getPrototypeOf(o) { return o.__proto__ || Object.getPrototypeOf(o); }; return _getPrototypeOf(o); }

  var GLTFLoader = /*#__PURE__*/function (_Loader) {
    _inherits(GLTFLoader, _Loader);

    var _super = _createSuper(GLTFLoader);

    function GLTFLoader(manager) {
      var _this;

      _classCallCheck(this, GLTFLoader);

      _this = _super.call(this, manager);
      _this.dracoLoader = null;
      _this.ktx2Loader = null;
      _this.meshoptDecoder = null;
      _this.pluginCallbacks = [];

      _this.register(function (parser) {
        return new GLTFMaterialsClearcoatExtension(parser);
      });

      _this.register(function (parser) {
        return new GLTFTextureBasisUExtension(parser);
      });

      _this.register(function (parser) {
        return new GLTFTextureWebPExtension(parser);
      });

      _this.register(function (parser) {
        return new GLTFMaterialsSheenExtension(parser);
      });

      _this.register(function (parser) {
        return new GLTFMaterialsTransmissionExtension(parser);
      });

      _this.register(function (parser) {
        return new GLTFMaterialsVolumeExtension(parser);
      });

      _this.register(function (parser) {
        return new GLTFMaterialsIorExtension(parser);
      });

      _this.register(function (parser) {
        return new GLTFMaterialsSpecularExtension(parser);
      });

      _this.register(function (parser) {
        return new GLTFLightsExtension(parser);
      });

      _this.register(function (parser) {
        return new GLTFMeshoptCompression(parser);
      });

      return _this;
    }

    _createClass(GLTFLoader, [{
      key: "load",
      value: function load(url, onLoad, onProgress, onError) {
        var scope = this;
        var resourcePath;

        if (this.resourcePath !== '') {
          resourcePath = this.resourcePath;
        } else if (this.path !== '') {
          resourcePath = this.path;
        } else {
          resourcePath = _three.LoaderUtils.extractUrlBase(url);
        } // Tells the LoadingManager to track an extra item, which resolves after
        // the model is fully loaded. This means the count of items loaded will
        // be incorrect, but ensures manager.onLoad() does not fire early.


        this.manager.itemStart(url);

        var _onError = function _onError(e) {
          if (onError) {
            onError(e);
          } else {
            console.error(e);
          }

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

        var loader = new _three.FileLoader(this.manager);
        loader.setPath(this.path);
        loader.setResponseType('arraybuffer');
        loader.setRequestHeader(this.requestHeader);
        loader.setWithCredentials(this.withCredentials);
        loader.load(url, function (data) {
          try {
            scope.parse(data, resourcePath, function (gltf) {
              onLoad(gltf);
              scope.manager.itemEnd(url);
            }, _onError);
          } catch (e) {
            _onError(e);
          }
        }, onProgress, _onError);
      }
    }, {
      key: "setDRACOLoader",
      value: function setDRACOLoader(dracoLoader) {
        this.dracoLoader = dracoLoader;
        return this;
      }
    }, {
      key: "setDDSLoader",
      value: function setDDSLoader() {
        throw new Error('THREE.GLTFLoader: "MSFT_texture_dds" no longer supported. Please update to "KHR_texture_basisu".');
      }
    }, {
      key: "setKTX2Loader",
      value: function setKTX2Loader(ktx2Loader) {
        this.ktx2Loader = ktx2Loader;
        return this;
      }
    }, {
      key: "setMeshoptDecoder",
      value: function setMeshoptDecoder(meshoptDecoder) {
        this.meshoptDecoder = meshoptDecoder;
        return this;
      }
    }, {
      key: "register",
      value: function register(callback) {
        if (this.pluginCallbacks.indexOf(callback) === -1) {
          this.pluginCallbacks.push(callback);
        }

        return this;
      }
    }, {
      key: "unregister",
      value: function unregister(callback) {
        if (this.pluginCallbacks.indexOf(callback) !== -1) {
          this.pluginCallbacks.splice(this.pluginCallbacks.indexOf(callback), 1);
        }

        return this;
      }
    }, {
      key: "parse",
      value: function parse(data, path, onLoad, onError) {
        var content;
        var extensions = {};
        var plugins = {};

        if (typeof data === 'string') {
          content = data;
        } else {
          var magic = _three.LoaderUtils.decodeText(new Uint8Array(data, 0, 4));

          if (magic === BINARY_EXTENSION_HEADER_MAGIC) {
            try {
              extensions[EXTENSIONS.KHR_BINARY_GLTF] = new GLTFBinaryExtension(data);
            } catch (error) {
              if (onError) onError(error);
              return;
            }

            content = extensions[EXTENSIONS.KHR_BINARY_GLTF].content;
          } else {
            content = _three.LoaderUtils.decodeText(new Uint8Array(data));
          }
        }

        var json = JSON.parse(content);

        if (json.asset === undefined || json.asset.version[0] < 2) {
          if (onError) onError(new Error('THREE.GLTFLoader: Unsupported asset. glTF versions >=2.0 are supported.'));
          return;
        }

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

        for (var i = 0; i < this.pluginCallbacks.length; i++) {
          var plugin = this.pluginCallbacks[i](parser);
          plugins[plugin.name] = plugin; // Workaround to avoid determining as unknown extension
          // in addUnknownExtensionsToUserData().
          // Remove this workaround if we move all the existing
          // extension handlers to plugin system

          extensions[plugin.name] = true;
        }

        if (json.extensionsUsed) {
          for (var _i = 0; _i < json.extensionsUsed.length; ++_i) {
            var extensionName = json.extensionsUsed[_i];
            var extensionsRequired = json.extensionsRequired || [];

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

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

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

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

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

              default:
                if (extensionsRequired.indexOf(extensionName) >= 0 && plugins[extensionName] === undefined) {
                  console.warn('THREE.GLTFLoader: Unknown extension "' + extensionName + '".');
                }

            }
          }
        }

        parser.setExtensions(extensions);
        parser.setPlugins(plugins);
        parser.parse(onLoad, onError);
      }
    }, {
      key: "parseAsync",
      value: function parseAsync(data, path) {
        var scope = this;
        return new Promise(function (resolve, reject) {
          scope.parse(data, path, resolve, reject);
        });
      }
    }]);

    return GLTFLoader;
  }(_three.Loader);
  /* GLTFREGISTRY */


  _exports.GLTFLoader = GLTFLoader;

  function GLTFRegistry() {
    var objects = {};
    return {
      get: function get(key) {
        return objects[key];
      },
      add: function add(key, object) {
        objects[key] = object;
      },
      remove: function remove(key) {
        delete objects[key];
      },
      removeAll: function removeAll() {
        objects = {};
      }
    };
  }
  /*********************************/

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

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


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

  var GLTFLightsExtension = /*#__PURE__*/function () {
    function GLTFLightsExtension(parser) {
      _classCallCheck(this, GLTFLightsExtension);

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

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

    _createClass(GLTFLightsExtension, [{
      key: "_markDefs",
      value: function _markDefs() {
        var parser = this.parser;
        var nodeDefs = this.parser.json.nodes || [];

        for (var nodeIndex = 0, nodeLength = nodeDefs.length; nodeIndex < nodeLength; nodeIndex++) {
          var nodeDef = nodeDefs[nodeIndex];

          if (nodeDef.extensions && nodeDef.extensions[this.name] && nodeDef.extensions[this.name].light !== undefined) {
            parser._addNodeRef(this.cache, nodeDef.extensions[this.name].light);
          }
        }
      }
    }, {
      key: "_loadLight",
      value: function _loadLight(lightIndex) {
        var parser = this.parser;
        var cacheKey = 'light:' + lightIndex;
        var dependency = parser.cache.get(cacheKey);
        if (dependency) return dependency;
        var json = parser.json;
        var extensions = json.extensions && json.extensions[this.name] || {};
        var lightDefs = extensions.lights || [];
        var lightDef = lightDefs[lightIndex];
        var lightNode;
        var color = new _three.Color(0xffffff);
        if (lightDef.color !== undefined) color.fromArray(lightDef.color);
        var range = lightDef.range !== undefined ? lightDef.range : 0;

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

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

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

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

          default:
            throw new Error('THREE.GLTFLoader: Unexpected light type: ' + lightDef.type);
        } // Some lights (e.g. spot) default to a position other than the origin. Reset the position
        // here, because node-level parsing will only override position if explicitly specified.


        lightNode.position.set(0, 0, 0);
        lightNode.decay = 2;
        if (lightDef.intensity !== undefined) lightNode.intensity = lightDef.intensity;
        lightNode.name = parser.createUniqueName(lightDef.name || 'light_' + lightIndex);
        dependency = Promise.resolve(lightNode);
        parser.cache.add(cacheKey, dependency);
        return dependency;
      }
    }, {
      key: "createNodeAttachment",
      value: function createNodeAttachment(nodeIndex) {
        var self = this;
        var parser = this.parser;
        var json = parser.json;
        var nodeDef = json.nodes[nodeIndex];
        var lightDef = nodeDef.extensions && nodeDef.extensions[this.name] || {};
        var lightIndex = lightDef.light;
        if (lightIndex === undefined) return null;
        return this._loadLight(lightIndex).then(function (light) {
          return parser._getNodeRef(self.cache, lightIndex, light);
        });
      }
    }]);

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


  var GLTFMaterialsUnlitExtension = /*#__PURE__*/function () {
    function GLTFMaterialsUnlitExtension() {
      _classCallCheck(this, GLTFMaterialsUnlitExtension);

      this.name = EXTENSIONS.KHR_MATERIALS_UNLIT;
    }

    _createClass(GLTFMaterialsUnlitExtension, [{
      key: "getMaterialType",
      value: function getMaterialType() {
        return _three.MeshBasicMaterial;
      }
    }, {
      key: "extendParams",
      value: function extendParams(materialParams, materialDef, parser) {
        var pending = [];
        materialParams.color = new _three.Color(1.0, 1.0, 1.0);
        materialParams.opacity = 1.0;
        var metallicRoughness = materialDef.pbrMetallicRoughness;

        if (metallicRoughness) {
          if (Array.isArray(metallicRoughness.baseColorFactor)) {
            var array = metallicRoughness.baseColorFactor;
            materialParams.color.fromArray(array);
            materialParams.opacity = array[3];
          }

          if (metallicRoughness.baseColorTexture !== undefined) {
            pending.push(parser.assignTexture(materialParams, 'map', metallicRoughness.baseColorTexture));
          }
        }

        return Promise.all(pending);
      }
    }]);

    return GLTFMaterialsUnlitExtension;
  }();
  /**
   * Clearcoat Materials Extension
   *
   * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_materials_clearcoat
   */


  var GLTFMaterialsClearcoatExtension = /*#__PURE__*/function () {
    function GLTFMaterialsClearcoatExtension(parser) {
      _classCallCheck(this, GLTFMaterialsClearcoatExtension);

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

    _createClass(GLTFMaterialsClearcoatExtension, [{
      key: "getMaterialType",
      value: function getMaterialType(materialIndex) {
        var parser = this.parser;
        var materialDef = parser.json.materials[materialIndex];
        if (!materialDef.extensions || !materialDef.extensions[this.name]) return null;
        return _three.MeshPhysicalMaterial;
      }
    }, {
      key: "extendMaterialParams",
      value: function extendMaterialParams(materialIndex, materialParams) {
        var parser = this.parser;
        var materialDef = parser.json.materials[materialIndex];

        if (!materialDef.extensions || !materialDef.extensions[this.name]) {
          return Promise.resolve();
        }

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

        if (extension.clearcoatFactor !== undefined) {
          materialParams.clearcoat = extension.clearcoatFactor;
        }

        if (extension.clearcoatTexture !== undefined) {
          pending.push(parser.assignTexture(materialParams, 'clearcoatMap', extension.clearcoatTexture));
        }

        if (extension.clearcoatRoughnessFactor !== undefined) {
          materialParams.clearcoatRoughness = extension.clearcoatRoughnessFactor;
        }

        if (extension.clearcoatRoughnessTexture !== undefined) {
          pending.push(parser.assignTexture(materialParams, 'clearcoatRoughnessMap', extension.clearcoatRoughnessTexture));
        }

        if (extension.clearcoatNormalTexture !== undefined) {
          pending.push(parser.assignTexture(materialParams, 'clearcoatNormalMap', extension.clearcoatNormalTexture));

          if (extension.clearcoatNormalTexture.scale !== undefined) {
            var scale = extension.clearcoatNormalTexture.scale;
            materialParams.clearcoatNormalScale = new _three.Vector2(scale, scale);
          }
        }

        return Promise.all(pending);
      }
    }]);

    return GLTFMaterialsClearcoatExtension;
  }();
  /**
   * Sheen Materials Extension
   *
   * Specification: https://github.com/KhronosGroup/glTF/tree/main/extensions/2.0/Khronos/KHR_materials_sheen
   */


  var GLTFMaterialsSheenExtension = /*#__PURE__*/function () {
    function GLTFMaterialsSheenExtension(parser) {
      _classCallCheck(this, GLTFMaterialsSheenExtension);

      this.parser = parser;
      this.name = EXTENSIONS.KHR_MATERIALS_SHEEN;
    }

    _createClass(GLTFMaterialsSheenExtension, [{
      key: "getMaterialType",
      value: function getMaterialType(materialIndex) {
        var parser = this.parser;
        var materialDef = parser.json.materials[materialIndex];
        if (!materialDef.extensions || !materialDef.extensions[this.name]) return null;
        return _three.MeshPhysicalMaterial;
      }
    }, {
      key: "extendMaterialParams",
      value: function extendMaterialParams(materialIndex, materialParams) {
        var parser = this.parser;
        var materialDef = parser.json.materials[materialIndex];

        if (!materialDef.extensions || !materialDef.extensions[this.name]) {
          return Promise.resolve();
        }

        var pending = [];
        materialParams.sheenColor = new _three.Color(0, 0, 0);
        materialParams.sheenRoughness = 0;
        materialParams.sheen = 1;
        var extension = materialDef.extensions[this.name];

        if (extension.sheenColorFactor !== undefined) {
          materialParams.sheenColor.fromArray(extension.sheenColorFactor);
        }

        if (extension.sheenRoughnessFactor !== undefined) {
          materialParams.sheenRoughness = extension.sheenRoughnessFactor;
        }

        if (extension.sheenColorTexture !== undefined) {
          pending.push(parser.assignTexture(materialParams, 'sheenColorMap', extension.sheenColorTexture));
        }

        if (extension.sheenRoughnessTexture !== undefined) {
          pending.push(parser.assignTexture(materialParams, 'sheenRoughnessMap', extension.sheenRoughnessTexture));
        }

        return Promise.all(pending);
      }
    }]);

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


  var GLTFMaterialsTransmissionExtension = /*#__PURE__*/function () {
    function GLTFMaterialsTransmissionExtension(parser) {
      _classCallCheck(this, GLTFMaterialsTransmissionExtension);

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

    _createClass(GLTFMaterialsTransmissionExtension, [{
      key: "getMaterialType",
      value: function getMaterialType(materialIndex) {
        var parser = this.parser;
        var materialDef = parser.json.materials[materialIndex];
        if (!materialDef.extensions || !materialDef.extensions[this.name]) return null;
        return _three.MeshPhysicalMaterial;
      }
    }, {
      key: "extendMaterialParams",
      value: function extendMaterialParams(materialIndex, materialParams) {
        var parser = this.parser;
        var materialDef = parser.json.materials[materialIndex];

        if (!materialDef.extensions || !materialDef.extensions[this.name]) {
          return Promise.resolve();
        }

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

        if (extension.transmissionFactor !== undefined) {
          materialParams.transmission = extension.transmissionFactor;
        }

        if (extension.transmissionTexture !== undefined) {
          pending.push(parser.assignTexture(materialParams, 'transmissionMap', extension.transmissionTexture));
        }

        return Promise.all(pending);
      }
    }]);

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


  var GLTFMaterialsVolumeExtension = /*#__PURE__*/function () {
    function GLTFMaterialsVolumeExtension(parser) {
      _classCallCheck(this, GLTFMaterialsVolumeExtension);

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

    _createClass(GLTFMaterialsVolumeExtension, [{
      key: "getMaterialType",
      value: function getMaterialType(materialIndex) {
        var parser = this.parser;
        var materialDef = parser.json.materials[materialIndex];
        if (!materialDef.extensions || !materialDef.extensions[this.name]) return null;
        return _three.MeshPhysicalMaterial;
      }
    }, {
      key: "extendMaterialParams",
      value: function extendMaterialParams(materialIndex, materialParams) {
        var parser = this.parser;
        var materialDef = parser.json.materials[materialIndex];

        if (!materialDef.extensions || !materialDef.extensions[this.name]) {
          return Promise.resolve();
        }

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

        if (extension.thicknessTexture !== undefined) {
          pending.push(parser.assignTexture(materialParams, 'thicknessMap', extension.thicknessTexture));
        }

        materialParams.attenuationDistance = extension.attenuationDistance || 0;
        var colorArray = extension.attenuationColor || [1, 1, 1];
        materialParams.attenuationColor = new _three.Color(colorArray[0], colorArray[1], colorArray[2]);
        return Promise.all(pending);
      }
    }]);

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


  var GLTFMaterialsIorExtension = /*#__PURE__*/function () {
    function GLTFMaterialsIorExtension(parser) {
      _classCallCheck(this, GLTFMaterialsIorExtension);

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

    _createClass(GLTFMaterialsIorExtension, [{
      key: "getMaterialType",
      value: function getMaterialType(materialIndex) {
        var parser = this.parser;
        var materialDef = parser.json.materials[materialIndex];
        if (!materialDef.extensions || !materialDef.extensions[this.name]) return null;
        return _three.MeshPhysicalMaterial;
      }
    }, {
      key: "extendMaterialParams",
      value: function extendMaterialParams(materialIndex, materialParams) {
        var parser = this.parser;
        var materialDef = parser.json.materials[materialIndex];

        if (!materialDef.extensions || !materialDef.extensions[this.name]) {
          return Promise.resolve();
        }

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

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


  var GLTFMaterialsSpecularExtension = /*#__PURE__*/function () {
    function GLTFMaterialsSpecularExtension(parser) {
      _classCallCheck(this, GLTFMaterialsSpecularExtension);

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

    _createClass(GLTFMaterialsSpecularExtension, [{
      key: "getMaterialType",
      value: function getMaterialType(materialIndex) {
        var parser = this.parser;
        var materialDef = parser.json.materials[materialIndex];
        if (!materialDef.extensions || !materialDef.extensions[this.name]) return null;
        return _three.MeshPhysicalMaterial;
      }
    }, {
      key: "extendMaterialParams",
      value: function extendMaterialParams(materialIndex, materialParams) {
        var parser = this.parser;
        var materialDef = parser.json.materials[materialIndex];

        if (!materialDef.extensions || !materialDef.extensions[this.name]) {
          return Promise.resolve();
        }

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

        if (extension.specularTexture !== undefined) {
          pending.push(parser.assignTexture(materialParams, 'specularIntensityMap', extension.specularTexture));
        }

        var colorArray = extension.specularColorFactor || [1, 1, 1];
        materialParams.specularColor = new _three.Color(colorArray[0], colorArray[1], colorArray[2]);

        if (extension.specularColorTexture !== undefined) {
          pending.push(parser.assignTexture(materialParams, 'specularColorMap', extension.specularColorTexture).then(function (texture) {
            texture.encoding = _three.sRGBEncoding;
          }));
        }

        return Promise.all(pending);
      }
    }]);

    return GLTFMaterialsSpecularExtension;
  }();
  /**
   * BasisU Texture Extension
   *
   * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_texture_basisu
   */


  var GLTFTextureBasisUExtension = /*#__PURE__*/function () {
    function GLTFTextureBasisUExtension(parser) {
      _classCallCheck(this, GLTFTextureBasisUExtension);

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

    _createClass(GLTFTextureBasisUExtension, [{
      key: "loadTexture",
      value: function loadTexture(textureIndex) {
        var parser = this.parser;
        var json = parser.json;
        var textureDef = json.textures[textureIndex];

        if (!textureDef.extensions || !textureDef.extensions[this.name]) {
          return null;
        }

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

        if (!loader) {
          if (json.extensionsRequired && json.extensionsRequired.indexOf(this.name) >= 0) {
            throw new Error('THREE.GLTFLoader: setKTX2Loader must be called before loading KTX2 textures');
          } else {
            // Assumes that the extension is optional and that a fallback texture is present
            return null;
          }
        }

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

    return GLTFTextureBasisUExtension;
  }();
  /**
   * WebP Texture Extension
   *
   * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Vendor/EXT_texture_webp
   */


  var GLTFTextureWebPExtension = /*#__PURE__*/function () {
    function GLTFTextureWebPExtension(parser) {
      _classCallCheck(this, GLTFTextureWebPExtension);

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

    _createClass(GLTFTextureWebPExtension, [{
      key: "loadTexture",
      value: function loadTexture(textureIndex) {
        var name = this.name;
        var parser = this.parser;
        var json = parser.json;
        var textureDef = json.textures[textureIndex];

        if (!textureDef.extensions || !textureDef.extensions[name]) {
          return null;
        }

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

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

        return this.detectSupport().then(function (isSupported) {
          if (isSupported) return parser.loadTextureImage(textureIndex, source, loader);

          if (json.extensionsRequired && json.extensionsRequired.indexOf(name) >= 0) {
            throw new Error('THREE.GLTFLoader: WebP required by asset but unsupported.');
          } // Fall back to PNG or JPEG.


          return parser.loadTexture(textureIndex);
        });
      }
    }, {
      key: "detectSupport",
      value: function detectSupport() {
        if (!this.isSupported) {
          this.isSupported = new Promise(function (resolve) {
            var image = new Image(); // Lossy test image. Support for lossy images doesn't guarantee support for all
            // WebP images, unfortunately.

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

            image.onload = image.onerror = function () {
              resolve(image.height === 1);
            };
          });
        }

        return this.isSupported;
      }
    }]);

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


  var GLTFMeshoptCompression = /*#__PURE__*/function () {
    function GLTFMeshoptCompression(parser) {
      _classCallCheck(this, GLTFMeshoptCompression);

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

    _createClass(GLTFMeshoptCompression, [{
      key: "loadBufferView",
      value: function loadBufferView(index) {
        var json = this.parser.json;
        var bufferView = json.bufferViews[index];

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

          if (!decoder || !decoder.supported) {
            if (json.extensionsRequired && json.extensionsRequired.indexOf(this.name) >= 0) {
              throw new Error('THREE.GLTFLoader: setMeshoptDecoder must be called before loading compressed files');
            } else {
              // Assumes that the extension is optional and that fallback buffer data is present
              return null;
            }
          }

          return Promise.all([buffer, decoder.ready]).then(function (res) {
            var byteOffset = extensionDef.byteOffset || 0;
            var byteLength = extensionDef.byteLength || 0;
            var count = extensionDef.count;
            var stride = extensionDef.byteStride;
            var result = new ArrayBuffer(count * stride);
            var source = new Uint8Array(res[0], byteOffset, byteLength);
            decoder.decodeGltfBuffer(new Uint8Array(result), count, stride, source, extensionDef.mode, extensionDef.filter);
            return result;
          });
        } else {
          return null;
        }
      }
    }]);

    return GLTFMeshoptCompression;
  }();
  /* BINARY EXTENSION */


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

  var GLTFBinaryExtension = /*#__PURE__*/_createClass(function GLTFBinaryExtension(data) {
    _classCallCheck(this, GLTFBinaryExtension);

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

    if (this.header.magic !== BINARY_EXTENSION_HEADER_MAGIC) {
      throw new Error('THREE.GLTFLoader: Unsupported glTF-Binary header.');
    } else if (this.header.version < 2.0) {
      throw new Error('THREE.GLTFLoader: Legacy binary file detected.');
    }

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

    while (chunkIndex < chunkContentsLength) {
      var chunkLength = chunkView.getUint32(chunkIndex, true);
      chunkIndex += 4;
      var chunkType = chunkView.getUint32(chunkIndex, true);
      chunkIndex += 4;

      if (chunkType === BINARY_EXTENSION_CHUNK_TYPES.JSON) {
        var contentArray = new Uint8Array(data, BINARY_EXTENSION_HEADER_LENGTH + chunkIndex, chunkLength);
        this.content = _three.LoaderUtils.decodeText(contentArray);
      } else if (chunkType === BINARY_EXTENSION_CHUNK_TYPES.BIN) {
        var byteOffset = BINARY_EXTENSION_HEADER_LENGTH + chunkIndex;
        this.body = data.slice(byteOffset, byteOffset + chunkLength);
      } // Clients must ignore chunks with unknown types.


      chunkIndex += chunkLength;
    }

    if (this.content === null) {
      throw new Error('THREE.GLTFLoader: JSON content not found.');
    }
  });
  /**
   * DRACO Mesh Compression Extension
   *
   * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_draco_mesh_compression
   */


  var GLTFDracoMeshCompressionExtension = /*#__PURE__*/function () {
    function GLTFDracoMeshCompressionExtension(json, dracoLoader) {
      _classCallCheck(this, GLTFDracoMeshCompressionExtension);

      if (!dracoLoader) {
        throw new Error('THREE.GLTFLoader: No DRACOLoader instance provided.');
      }

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

    _createClass(GLTFDracoMeshCompressionExtension, [{
      key: "decodePrimitive",
      value: function decodePrimitive(primitive, parser) {
        var json = this.json;
        var dracoLoader = this.dracoLoader;
        var bufferViewIndex = primitive.extensions[this.name].bufferView;
        var gltfAttributeMap = primitive.extensions[this.name].attributes;
        var threeAttributeMap = {};
        var attributeNormalizedMap = {};
        var attributeTypeMap = {};

        for (var attributeName in gltfAttributeMap) {
          var threeAttributeName = ATTRIBUTES[attributeName] || attributeName.toLowerCase();
          threeAttributeMap[threeAttributeName] = gltfAttributeMap[attributeName];
        }

        for (var _attributeName in primitive.attributes) {
          var _threeAttributeName = ATTRIBUTES[_attributeName] || _attributeName.toLowerCase();

          if (gltfAttributeMap[_attributeName] !== undefined) {
            var accessorDef = json.accessors[primitive.attributes[_attributeName]];
            var componentType = WEBGL_COMPONENT_TYPES[accessorDef.componentType];
            attributeTypeMap[_threeAttributeName] = componentType;
            attributeNormalizedMap[_threeAttributeName] = accessorDef.normalized === true;
          }
        }

        return parser.getDependency('bufferView', bufferViewIndex).then(function (bufferView) {
          return new Promise(function (resolve) {
            dracoLoader.decodeDracoFile(bufferView, function (geometry) {
              for (var _attributeName2 in geometry.attributes) {
                var attribute = geometry.attributes[_attributeName2];
                var normalized = attributeNormalizedMap[_attributeName2];
                if (normalized !== undefined) attribute.normalized = normalized;
              }

              resolve(geometry);
            }, threeAttributeMap, attributeTypeMap);
          });
        });
      }
    }]);

    return GLTFDracoMeshCompressionExtension;
  }();
  /**
   * Texture Transform Extension
   *
   * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_texture_transform
   */


  var GLTFTextureTransformExtension = /*#__PURE__*/function () {
    function GLTFTextureTransformExtension() {
      _classCallCheck(this, GLTFTextureTransformExtension);

      this.name = EXTENSIONS.KHR_TEXTURE_TRANSFORM;
    }

    _createClass(GLTFTextureTransformExtension, [{
      key: "extendTexture",
      value: function extendTexture(texture, transform) {
        if (transform.texCoord !== undefined) {
          console.warn('THREE.GLTFLoader: Custom UV sets in "' + this.name + '" extension not yet supported.');
        }

        if (transform.offset === undefined && transform.rotation === undefined && transform.scale === undefined) {
          // See https://github.com/mrdoob/three.js/issues/21819.
          return texture;
        }

        texture = texture.clone();

        if (transform.offset !== undefined) {
          texture.offset.fromArray(transform.offset);
        }

        if (transform.rotation !== undefined) {
          texture.rotation = transform.rotation;
        }

        if (transform.scale !== undefined) {
          texture.repeat.fromArray(transform.scale);
        }

        texture.needsUpdate = true;
        return texture;
      }
    }]);

    return GLTFTextureTransformExtension;
  }();
  /**
   * Specular-Glossiness Extension
   *
   * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_materials_pbrSpecularGlossiness
   */

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


  var GLTFMeshStandardSGMaterial = /*#__PURE__*/function (_MeshStandardMaterial) {
    _inherits(GLTFMeshStandardSGMaterial, _MeshStandardMaterial);

    var _super2 = _createSuper(GLTFMeshStandardSGMaterial);

    function GLTFMeshStandardSGMaterial(params) {
      var _this2;

      _classCallCheck(this, GLTFMeshStandardSGMaterial);

      _this2 = _super2.call(this);
      _this2.isGLTFSpecularGlossinessMaterial = true; //various chunks that need replacing

      var specularMapParsFragmentChunk = ['#ifdef USE_SPECULARMAP', '	uniform sampler2D specularMap;', '#endif'].join('\n');
      var glossinessMapParsFragmentChunk = ['#ifdef USE_GLOSSINESSMAP', '	uniform sampler2D glossinessMap;', '#endif'].join('\n');
      var specularMapFragmentChunk = ['vec3 specularFactor = specular;', '#ifdef USE_SPECULARMAP', '	vec4 texelSpecular = texture2D( specularMap, vUv );', '	texelSpecular = sRGBToLinear( texelSpecular );', '	// reads channel RGB, compatible with a glTF Specular-Glossiness (RGBA) texture', '	specularFactor *= texelSpecular.rgb;', '#endif'].join('\n');
      var glossinessMapFragmentChunk = ['float glossinessFactor = glossiness;', '#ifdef USE_GLOSSINESSMAP', '	vec4 texelGlossiness = texture2D( glossinessMap, vUv );', '	// reads channel A, compatible with a glTF Specular-Glossiness (RGBA) texture', '	glossinessFactor *= texelGlossiness.a;', '#endif'].join('\n');
      var lightPhysicalFragmentChunk = ['PhysicalMaterial material;', 'material.diffuseColor = diffuseColor.rgb * ( 1. - max( specularFactor.r, max( specularFactor.g, specularFactor.b ) ) );', 'vec3 dxy = max( abs( dFdx( geometryNormal ) ), abs( dFdy( geometryNormal ) ) );', 'float geometryRoughness = max( max( dxy.x, dxy.y ), dxy.z );', 'material.roughness = max( 1.0 - glossinessFactor, 0.0525 ); // 0.0525 corresponds to the base mip of a 256 cubemap.', 'material.roughness += geometryRoughness;', 'material.roughness = min( material.roughness, 1.0 );', 'material.specularColor = specularFactor;'].join('\n');
      var uniforms = {
        specular: {
          value: new _three.Color().setHex(0xffffff)
        },
        glossiness: {
          value: 1
        },
        specularMap: {
          value: null
        },
        glossinessMap: {
          value: null
        }
      };
      _this2._extraUniforms = uniforms;

      _this2.onBeforeCompile = function (shader) {
        for (var uniformName in uniforms) {
          shader.uniforms[uniformName] = uniforms[uniformName];
        }

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

      Object.defineProperties(_assertThisInitialized(_this2), {
        specular: {
          get: function get() {
            return uniforms.specular.value;
          },
          set: function set(v) {
            uniforms.specular.value = v;
          }
        },
        specularMap: {
          get: function get() {
            return uniforms.specularMap.value;
          },
          set: function set(v) {
            uniforms.specularMap.value = v;

            if (v) {
              this.defines.USE_SPECULARMAP = ''; // USE_UV is set by the renderer for specular maps
            } else {
              delete this.defines.USE_SPECULARMAP;
            }
          }
        },
        glossiness: {
          get: function get() {
            return uniforms.glossiness.value;
          },
          set: function set(v) {
            uniforms.glossiness.value = v;
          }
        },
        glossinessMap: {
          get: function get() {
            return uniforms.glossinessMap.value;
          },
          set: function set(v) {
            uniforms.glossinessMap.value = v;

            if (v) {
              this.defines.USE_GLOSSINESSMAP = '';
              this.defines.USE_UV = '';
            } else {
              delete this.defines.USE_GLOSSINESSMAP;
              delete this.defines.USE_UV;
            }
          }
        }
      });
      delete _this2.metalness;
      delete _this2.roughness;
      delete _this2.metalnessMap;
      delete _this2.roughnessMap;

      _this2.setValues(params);

      return _this2;
    }

    _createClass(GLTFMeshStandardSGMaterial, [{
      key: "copy",
      value: function copy(source) {
        _get(_getPrototypeOf(GLTFMeshStandardSGMaterial.prototype), "copy", this).call(this, source);

        this.specularMap = source.specularMap;
        this.specular.copy(source.specular);
        this.glossinessMap = source.glossinessMap;
        this.glossiness = source.glossiness;
        delete this.metalness;
        delete this.roughness;
        delete this.metalnessMap;
        delete this.roughnessMap;
        return this;
      }
    }]);

    return GLTFMeshStandardSGMaterial;
  }(_three.MeshStandardMaterial);

  var GLTFMaterialsPbrSpecularGlossinessExtension = /*#__PURE__*/function () {
    function GLTFMaterialsPbrSpecularGlossinessExtension() {
      _classCallCheck(this, GLTFMaterialsPbrSpecularGlossinessExtension);

      this.name = EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS;
      this.specularGlossinessParams = ['color', 'map', 'lightMap', 'lightMapIntensity', 'aoMap', 'aoMapIntensity', 'emissive', 'emissiveIntensity', 'emissiveMap', 'bumpMap', 'bumpScale', 'normalMap', 'normalMapType', 'displacementMap', 'displacementScale', 'displacementBias', 'specularMap', 'specular', 'glossinessMap', 'glossiness', 'alphaMap', 'envMap', 'envMapIntensity', 'refractionRatio'];
    }

    _createClass(GLTFMaterialsPbrSpecularGlossinessExtension, [{
      key: "getMaterialType",
      value: function getMaterialType() {
        return GLTFMeshStandardSGMaterial;
      }
    }, {
      key: "extendParams",
      value: function extendParams(materialParams, materialDef, parser) {
        var pbrSpecularGlossiness = materialDef.extensions[this.name];
        materialParams.color = new _three.Color(1.0, 1.0, 1.0);
        materialParams.opacity = 1.0;
        var pending = [];

        if (Array.isArray(pbrSpecularGlossiness.diffuseFactor)) {
          var array = pbrSpecularGlossiness.diffuseFactor;
          materialParams.color.fromArray(array);
          materialParams.opacity = array[3];
        }

        if (pbrSpecularGlossiness.diffuseTexture !== undefined) {
          pending.push(parser.assignTexture(materialParams, 'map', pbrSpecularGlossiness.diffuseTexture));
        }

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

        if (Array.isArray(pbrSpecularGlossiness.specularFactor)) {
          materialParams.specular.fromArray(pbrSpecularGlossiness.specularFactor);
        }

        if (pbrSpecularGlossiness.specularGlossinessTexture !== undefined) {
          var specGlossMapDef = pbrSpecularGlossiness.specularGlossinessTexture;
          pending.push(parser.assignTexture(materialParams, 'glossinessMap', specGlossMapDef));
          pending.push(parser.assignTexture(materialParams, 'specularMap', specGlossMapDef));
        }

        return Promise.all(pending);
      }
    }, {
      key: "createMaterial",
      value: function createMaterial(materialParams) {
        var material = new GLTFMeshStandardSGMaterial(materialParams);
        material.fog = true;
        material.color = materialParams.color;
        material.map = materialParams.map === undefined ? null : materialParams.map;
        material.lightMap = null;
        material.lightMapIntensity = 1.0;
        material.aoMap = materialParams.aoMap === undefined ? null : materialParams.aoMap;
        material.aoMapIntensity = 1.0;
        material.emissive = materialParams.emissive;
        material.emissiveIntensity = 1.0;
        material.emissiveMap = materialParams.emissiveMap === undefined ? null : materialParams.emissiveMap;
        material.bumpMap = materialParams.bumpMap === undefined ? null : materialParams.bumpMap;
        material.bumpScale = 1;
        material.normalMap = materialParams.normalMap === undefined ? null : materialParams.normalMap;
        material.normalMapType = _three.TangentSpaceNormalMap;
        if (materialParams.normalScale) material.normalScale = materialParams.normalScale;
        material.displacementMap = null;
        material.displacementScale = 1;
        material.displacementBias = 0;
        material.specularMap = materialParams.specularMap === undefined ? null : materialParams.specularMap;
        material.specular = materialParams.specular;
        material.glossinessMap = materialParams.glossinessMap === undefined ? null : materialParams.glossinessMap;
        material.glossiness = materialParams.glossiness;
        material.alphaMap = null;
        material.envMap = materialParams.envMap === undefined ? null : materialParams.envMap;
        material.envMapIntensity = 1.0;
        material.refractionRatio = 0.98;
        return material;
      }
    }]);

    return GLTFMaterialsPbrSpecularGlossinessExtension;
  }();
  /**
   * Mesh Quantization Extension
   *
   * Specification: https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_mesh_quantization
   */


  var GLTFMeshQuantizationExtension = /*#__PURE__*/_createClass(function GLTFMeshQuantizationExtension() {
    _classCallCheck(this, GLTFMeshQuantizationExtension);

    this.name = EXTENSIONS.KHR_MESH_QUANTIZATION;
  });
  /*********************************/

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

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


  var GLTFCubicSplineInterpolant = /*#__PURE__*/function (_Interpolant) {
    _inherits(GLTFCubicSplineInterpolant, _Interpolant);

    var _super3 = _createSuper(GLTFCubicSplineInterpolant);

    function GLTFCubicSplineInterpolant(parameterPositions, sampleValues, sampleSize, resultBuffer) {
      _classCallCheck(this, GLTFCubicSplineInterpolant);

      return _super3.call(this, parameterPositions, sampleValues, sampleSize, resultBuffer);
    }

    _createClass(GLTFCubicSplineInterpolant, [{
      key: "copySampleValue_",
      value: function copySampleValue_(index) {
        // Copies a sample value to the result buffer. See description of glTF
        // CUBICSPLINE values layout in interpolate_() function below.
        var result = this.resultBuffer,
            values = this.sampleValues,
            valueSize = this.valueSize,
            offset = index * valueSize * 3 + valueSize;

        for (var i = 0; i !== valueSize; i++) {
          result[i] = values[offset + i];
        }

        return result;
      }
    }]);

    return GLTFCubicSplineInterpolant;
  }(_three.Interpolant);

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

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

    for (var i = 0; i !== stride; i++) {
      var p0 = values[offset0 + i + stride]; // splineVertex_k

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

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

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

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

    return result;
  };

  var _q = new _three.Quaternion();

  var GLTFCubicSplineQuaternionInterpolant = /*#__PURE__*/function (_GLTFCubicSplineInter) {
    _inherits(GLTFCubicSplineQuaternionInterpolant, _GLTFCubicSplineInter);

    var _super4 = _createSuper(GLTFCubicSplineQuaternionInterpolant);

    function GLTFCubicSplineQuaternionInterpolant() {
      _classCallCheck(this, GLTFCubicSplineQuaternionInterpolant);

      return _super4.apply(this, arguments);
    }

    _createClass(GLTFCubicSplineQuaternionInterpolant, [{
      key: "interpolate_",
      value: function interpolate_(i1, t0, t, t1) {
        var result = _get(_getPrototypeOf(GLTFCubicSplineQuaternionInterpolant.prototype), "interpolate_", this).call(this, i1, t0, t, t1);

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

        return result;
      }
    }]);

    return GLTFCubicSplineQuaternionInterpolant;
  }(GLTFCubicSplineInterpolant);
  /*********************************/

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

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

  /* CONSTANTS */


  var WEBGL_CONSTANTS = {
    FLOAT: 5126,
    //FLOAT_MAT2: 35674,
    FLOAT_MAT3: 35675,
    FLOAT_MAT4: 35676,
    FLOAT_VEC2: 35664,
    FLOAT_VEC3: 35665,
    FLOAT_VEC4: 35666,
    LINEAR: 9729,
    REPEAT: 10497,
    SAMPLER_2D: 35678,
    POINTS: 0,
    LINES: 1,
    LINE_LOOP: 2,
    LINE_STRIP: 3,
    TRIANGLES: 4,
    TRIANGLE_STRIP: 5,
    TRIANGLE_FAN: 6,
    UNSIGNED_BYTE: 5121,
    UNSIGNED_SHORT: 5123
  };
  var WEBGL_COMPONENT_TYPES = {
    5120: Int8Array,
    5121: Uint8Array,
    5122: Int16Array,
    5123: Uint16Array,
    5125: Uint32Array,
    5126: Float32Array
  };
  var WEBGL_FILTERS = {
    9728: _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_TYPE_SIZES = {
    'SCALAR': 1,
    'VEC2': 2,
    'VEC3': 3,
    'VEC4': 4,
    'MAT2': 4,
    'MAT3': 9,
    'MAT4': 16
  };
  var ATTRIBUTES = {
    POSITION: 'position',
    NORMAL: 'normal',
    TANGENT: 'tangent',
    TEXCOORD_0: 'uv',
    TEXCOORD_1: 'uv2',
    COLOR_0: 'color',
    WEIGHTS_0: 'skinWeight',
    JOINTS_0: 'skinIndex'
  };
  var PATH_PROPERTIES = {
    scale: 'scale',
    translation: 'position',
    rotation: 'quaternion',
    weights: 'morphTargetInfluences'
  };
  var INTERPOLATION = {
    CUBICSPLINE: undefined,
    // We use a custom interpolant (GLTFCubicSplineInterpolation) for CUBICSPLINE tracks. Each
    // keyframe track will be initialized with a default interpolation type, then modified.
    LINEAR: _three.InterpolateLinear,
    STEP: _three.InterpolateDiscrete
  };
  var ALPHA_MODES = {
    OPAQUE: 'OPAQUE',
    MASK: 'MASK',
    BLEND: 'BLEND'
  };
  /**
   * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#default-material
   */

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

    return cache['DefaultMaterial'];
  }

  function addUnknownExtensionsToUserData(knownExtensions, object, objectDef) {
    // Add unknown glTF extensions to an object's userData.
    for (var name in objectDef.extensions) {
      if (knownExtensions[name] === undefined) {
        object.userData.gltfExtensions = object.userData.gltfExtensions || {};
        object.userData.gltfExtensions[name] = objectDef.extensions[name];
      }
    }
  }
  /**
   * @param {Object3D|Material|BufferGeometry} object
   * @param {GLTF.definition} gltfDef
   */


  function assignExtrasToUserData(object, gltfDef) {
    if (gltfDef.extras !== undefined) {
      if (typeof gltfDef.extras === 'object') {
        Object.assign(object.userData, gltfDef.extras);
      } else {
        console.warn('THREE.GLTFLoader: Ignoring primitive type .extras, ' + gltfDef.extras);
      }
    }
  }
  /**
   * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#morph-targets
   *
   * @param {BufferGeometry} geometry
   * @param {Array<GLTF.Target>} targets
   * @param {GLTFParser} parser
   * @return {Promise<BufferGeometry>}
   */


  function addMorphTargets(geometry, targets, parser) {
    var hasMorphPosition = false;
    var hasMorphNormal = false;

    for (var i = 0, il = targets.length; i < il; i++) {
      var target = targets[i];
      if (target.POSITION !== undefined) hasMorphPosition = true;
      if (target.NORMAL !== undefined) hasMorphNormal = true;
      if (hasMorphPosition && hasMorphNormal) break;
    }

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

    for (var _i2 = 0, _il = targets.length; _i2 < _il; _i2++) {
      var _target = targets[_i2];

      if (hasMorphPosition) {
        var pendingAccessor = _target.POSITION !== undefined ? parser.getDependency('accessor', _target.POSITION) : geometry.attributes.position;
        pendingPositionAccessors.push(pendingAccessor);
      }

      if (hasMorphNormal) {
        var _pendingAccessor = _target.NORMAL !== undefined ? parser.getDependency('accessor', _target.NORMAL) : geometry.attributes.normal;

        pendingNormalAccessors.push(_pendingAccessor);
      }
    }

    return Promise.all([Promise.all(pendingPositionAccessors), Promise.all(pendingNormalAccessors)]).then(function (accessors) {
      var morphPositions = accessors[0];
      var morphNormals = accessors[1];
      if (hasMorphPosition) geometry.morphAttributes.position = morphPositions;
      if (hasMorphNormal) geometry.morphAttributes.normal = morphNormals;
      geometry.morphTargetsRelative = true;
      return geometry;
    });
  }
  /**
   * @param {Mesh} mesh
   * @param {GLTF.Mesh} meshDef
   */


  function updateMorphTargets(mesh, meshDef) {
    mesh.updateMorphTargets();

    if (meshDef.weights !== undefined) {
      for (var i = 0, il = meshDef.weights.length; i < il; i++) {
        mesh.morphTargetInfluences[i] = meshDef.weights[i];
      }
    } // .extras has user-defined data, so check that .extras.targetNames is an array.


    if (meshDef.extras && Array.isArray(meshDef.extras.targetNames)) {
      var targetNames = meshDef.extras.targetNames;

      if (mesh.morphTargetInfluences.length === targetNames.length) {
        mesh.morphTargetDictionary = {};

        for (var _i3 = 0, _il2 = targetNames.length; _i3 < _il2; _i3++) {
          mesh.morphTargetDictionary[targetNames[_i3]] = _i3;
        }
      } else {
        console.warn('THREE.GLTFLoader: Invalid extras.targetNames length. Ignoring names.');
      }
    }
  }

  function createPrimitiveKey(primitiveDef) {
    var dracoExtension = primitiveDef.extensions && primitiveDef.extensions[EXTENSIONS.KHR_DRACO_MESH_COMPRESSION];
    var geometryKey;

    if (dracoExtension) {
      geometryKey = 'draco:' + dracoExtension.bufferView + ':' + dracoExtension.indices + ':' + createAttributesKey(dracoExtension.attributes);
    } else {
      geometryKey = primitiveDef.indices + ':' + createAttributesKey(primitiveDef.attributes) + ':' + primitiveDef.mode;
    }

    return geometryKey;
  }

  function createAttributesKey(attributes) {
    var attributesKey = '';
    var keys = Object.keys(attributes).sort();

    for (var i = 0, il = keys.length; i < il; i++) {
      attributesKey += keys[i] + ':' + attributes[keys[i]] + ';';
    }

    return attributesKey;
  }

  function getNormalizedComponentScale(constructor) {
    // Reference:
    // https://github.com/KhronosGroup/glTF/tree/master/extensions/2.0/Khronos/KHR_mesh_quantization#encoding-quantized-data
    switch (constructor) {
      case Int8Array:
        return 1 / 127;

      case Uint8Array:
        return 1 / 255;

      case Int16Array:
        return 1 / 32767;

      case Uint16Array:
        return 1 / 65535;

      default:
        throw new Error('THREE.GLTFLoader: Unsupported normalized accessor component type.');
    }
  }
  /* GLTF PARSER */


  var GLTFParser = /*#__PURE__*/function () {
    function GLTFParser() {
      var json = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : {};
      var options = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {};

      _classCallCheck(this, GLTFParser);

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

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

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

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

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

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

      if (typeof createImageBitmap !== 'undefined' && /Firefox/.test(navigator.userAgent) === false) {
        this.textureLoader = new _three.ImageBitmapLoader(this.options.manager);
      } else {
        this.textureLoader = new _three.TextureLoader(this.options.manager);
      }

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

      if (this.options.crossOrigin === 'use-credentials') {
        this.fileLoader.setWithCredentials(true);
      }
    }

    _createClass(GLTFParser, [{
      key: "setExtensions",
      value: function setExtensions(extensions) {
        this.extensions = extensions;
      }
    }, {
      key: "setPlugins",
      value: function setPlugins(plugins) {
        this.plugins = plugins;
      }
    }, {
      key: "parse",
      value: function parse(onLoad, onError) {
        var parser = this;
        var json = this.json;
        var extensions = this.extensions; // Clear the loader cache

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

        this._invokeAll(function (ext) {
          return ext._markDefs && ext._markDefs();
        });

        Promise.all(this._invokeAll(function (ext) {
          return ext.beforeRoot && ext.beforeRoot();
        })).then(function () {
          return Promise.all([parser.getDependencies('scene'), parser.getDependencies('animation'), parser.getDependencies('camera')]);
        }).then(function (dependencies) {
          var result = {
            scene: dependencies[0][json.scene || 0],
            scenes: dependencies[0],
            animations: dependencies[1],
            cameras: dependencies[2],
            asset: json.asset,
            parser: parser,
            userData: {}
          };
          addUnknownExtensionsToUserData(extensions, result, json);
          assignExtrasToUserData(result, json);
          Promise.all(parser._invokeAll(function (ext) {
            return ext.afterRoot && ext.afterRoot(result);
          })).then(function () {
            onLoad(result);
          });
        }).catch(onError);
      }
      /**
       * Marks the special nodes/meshes in json for efficient parse.
       */

    }, {
      key: "_markDefs",
      value: function _markDefs() {
        var nodeDefs = this.json.nodes || [];
        var skinDefs = this.json.skins || [];
        var meshDefs = this.json.meshes || []; // Nothing in the node definition indicates whether it is a Bone or an
        // Object3D. Use the skins' joint references to mark bones.

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


        for (var nodeIndex = 0, nodeLength = nodeDefs.length; nodeIndex < nodeLength; nodeIndex++) {
          var nodeDef = nodeDefs[nodeIndex];

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


            if (nodeDef.skin !== undefined) {
              meshDefs[nodeDef.mesh].isSkinnedMesh = true;
            }
          }

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

    }, {
      key: "_addNodeRef",
      value: function _addNodeRef(cache, index) {
        if (index === undefined) return;

        if (cache.refs[index] === undefined) {
          cache.refs[index] = cache.uses[index] = 0;
        }

        cache.refs[index]++;
      }
      /** Returns a reference to a shared resource, cloning it if necessary. */

    }, {
      key: "_getNodeRef",
      value: function _getNodeRef(cache, index, object) {
        var _this3 = this;

        if (cache.refs[index] <= 1) return object;
        var ref = object.clone(); // Propagates mappings to the cloned object, prevents mappings on the
        // original object from being lost.

        var updateMappings = function updateMappings(original, clone) {
          var mappings = _this3.associations.get(original);

          if (mappings != null) {
            _this3.associations.set(clone, mappings);
          }

          var _iterator = _createForOfIteratorHelper(original.children.entries()),
              _step;

          try {
            for (_iterator.s(); !(_step = _iterator.n()).done;) {
              var _step$value = _slicedToArray(_step.value, 2),
                  i = _step$value[0],
                  child = _step$value[1];

              updateMappings(child, clone.children[i]);
            }
          } catch (err) {
            _iterator.e(err);
          } finally {
            _iterator.f();
          }
        };

        updateMappings(object, ref);
        ref.name += '_instance_' + cache.uses[index]++;
        return ref;
      }
    }, {
      key: "_invokeOne",
      value: function _invokeOne(func) {
        var extensions = Object.values(this.plugins);
        extensions.push(this);

        for (var i = 0; i < extensions.length; i++) {
          var result = func(extensions[i]);
          if (result) return result;
        }

        return null;
      }
    }, {
      key: "_invokeAll",
      value: function _invokeAll(func) {
        var extensions = Object.values(this.plugins);
        extensions.unshift(this);
        var pending = [];

        for (var i = 0; i < extensions.length; i++) {
          var result = func(extensions[i]);
          if (result) pending.push(result);
        }

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

    }, {
      key: "getDependency",
      value: function getDependency(type, index) {
        var cacheKey = type + ':' + index;
        var dependency = this.cache.get(cacheKey);

        if (!dependency) {
          switch (type) {
            case 'scene':
              dependency = this.loadScene(index);
              break;

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

            case 'mesh':
              dependency = this._invokeOne(function (ext) {
                return ext.loadMesh && ext.loadMesh(index);
              });
              break;

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

            case 'bufferView':
              dependency = this._invokeOne(function (ext) {
                return ext.loadBufferView && ext.loadBufferView(index);
              });
              break;

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

            case 'material':
              dependency = this._invokeOne(function (ext) {
                return ext.loadMaterial && ext.loadMaterial(index);
              });
              break;

            case 'texture':
              dependency = this._invokeOne(function (ext) {
                return ext.loadTexture && ext.loadTexture(index);
              });
              break;

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

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

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

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

          this.cache.add(cacheKey, dependency);
        }

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

    }, {
      key: "getDependencies",
      value: function getDependencies(type) {
        var dependencies = this.cache.get(type);

        if (!dependencies) {
          var parser = this;
          var defs = this.json[type + (type === 'mesh' ? 'es' : 's')] || [];
          dependencies = Promise.all(defs.map(function (def, index) {
            return parser.getDependency(type, index);
          }));
          this.cache.add(type, dependencies);
        }

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

    }, {
      key: "loadBuffer",
      value: function loadBuffer(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(_three.LoaderUtils.resolveURL(bufferDef.uri, options.path), resolve, undefined, function () {
            reject(new Error('THREE.GLTFLoader: Failed to load buffer "' + bufferDef.uri + '".'));
          });
        });
      }
      /**
       * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#buffers-and-buffer-views
       * @param {number} bufferViewIndex
       * @return {Promise<ArrayBuffer>}
       */

    }, {
      key: "loadBufferView",
      value: function loadBufferView(bufferViewIndex) {
        var bufferViewDef = this.json.bufferViews[bufferViewIndex];
        return this.getDependency('buffer', bufferViewDef.buffer).then(function (buffer) {
          var byteLength = bufferViewDef.byteLength || 0;
          var byteOffset = bufferViewDef.byteOffset || 0;
          return buffer.slice(byteOffset, byteOffset + byteLength);
        });
      }
      /**
       * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#accessors
       * @param {number} accessorIndex
       * @return {Promise<BufferAttribute|InterleavedBufferAttribute>}
       */

    }, {
      key: "loadAccessor",
      value: function loadAccessor(accessorIndex) {
        var parser = this;
        var json = this.json;
        var accessorDef = this.json.accessors[accessorIndex];

        if (accessorDef.bufferView === undefined && accessorDef.sparse === undefined) {
          // Ignore empty accessors, which may be used to declare runtime
          // information about attributes coming from another source (e.g. Draco
          // compression extension).
          return Promise.resolve(null);
        }

        var pendingBufferViews = [];

        if (accessorDef.bufferView !== undefined) {
          pendingBufferViews.push(this.getDependency('bufferView', accessorDef.bufferView));
        } else {
          pendingBufferViews.push(null);
        }

        if (accessorDef.sparse !== undefined) {
          pendingBufferViews.push(this.getDependency('bufferView', accessorDef.sparse.indices.bufferView));
          pendingBufferViews.push(this.getDependency('bufferView', accessorDef.sparse.values.bufferView));
        }

        return Promise.all(pendingBufferViews).then(function (bufferViews) {
          var bufferView = bufferViews[0];
          var itemSize = WEBGL_TYPE_SIZES[accessorDef.type];
          var TypedArray = WEBGL_COMPONENT_TYPES[accessorDef.componentType]; // For VEC3: itemSize is 3, elementBytes is 4, itemBytes is 12.

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

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

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

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

            bufferAttribute = new _three.InterleavedBufferAttribute(ib, itemSize, byteOffset % byteStride / elementBytes, normalized);
          } else {
            if (bufferView === null) {
              array = new TypedArray(accessorDef.count * itemSize);
            } else {
              array = new TypedArray(bufferView, byteOffset, accessorDef.count * itemSize);
            }

            bufferAttribute = new _three.BufferAttribute(array, itemSize, normalized);
          } // https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#sparse-accessors


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

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

            for (var i = 0, il = sparseIndices.length; i < il; i++) {
              var index = sparseIndices[i];
              bufferAttribute.setX(index, sparseValues[i * itemSize]);
              if (itemSize >= 2) bufferAttribute.setY(index, sparseValues[i * itemSize + 1]);
              if (itemSize >= 3) bufferAttribute.setZ(index, sparseValues[i * itemSize + 2]);
              if (itemSize >= 4) bufferAttribute.setW(index, sparseValues[i * itemSize + 3]);
              if (itemSize >= 5) throw new Error('THREE.GLTFLoader: Unsupported itemSize in sparse BufferAttribute.');
            }
          }

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

    }, {
      key: "loadTexture",
      value: function loadTexture(textureIndex) {
        var json = this.json;
        var options = this.options;
        var textureDef = json.textures[textureIndex];
        var source = json.images[textureDef.source];
        var loader = this.textureLoader;

        if (source.uri) {
          var handler = options.manager.getHandler(source.uri);
          if (handler !== null) loader = handler;
        }

        return this.loadTextureImage(textureIndex, source, loader);
      }
    }, {
      key: "loadTextureImage",
      value: function loadTextureImage(textureIndex, source, loader) {
        var parser = this;
        var json = this.json;
        var options = this.options;
        var textureDef = json.textures[textureIndex];
        var cacheKey = (source.uri || source.bufferView) + ':' + textureDef.sampler;

        if (this.textureCache[cacheKey]) {
          // See https://github.com/mrdoob/three.js/issues/21559.
          return this.textureCache[cacheKey];
        }

        var URL = self.URL || self.webkitURL;
        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;
          });
        } else if (source.uri === undefined) {
          throw new Error('THREE.GLTFLoader: Image ' + textureIndex + ' is missing URI and bufferView');
        }

        var promise = Promise.resolve(sourceURI).then(function (sourceURI) {
          return new Promise(function (resolve, reject) {
            var onLoad = resolve;

            if (loader.isImageBitmapLoader === true) {
              onLoad = function onLoad(imageBitmap) {
                var texture = new _three.Texture(imageBitmap);
                texture.needsUpdate = true;
                resolve(texture);
              };
            }

            loader.load(_three.LoaderUtils.resolveURL(sourceURI, options.path), onLoad, undefined, reject);
          });
        }).then(function (texture) {
          // Clean up resources and configure Texture.
          if (isObjectURL === true) {
            URL.revokeObjectURL(sourceURI);
          }

          texture.flipY = false;
          if (textureDef.name) texture.name = textureDef.name;
          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;
          parser.associations.set(texture, {
            textures: textureIndex
          });
          return texture;
        }).catch(function () {
          console.error('THREE.GLTFLoader: Couldn\'t load texture', sourceURI);
          return null;
        });
        this.textureCache[cacheKey] = promise;
        return promise;
      }
      /**
       * Asynchronously assigns a texture to the given material parameters.
       * @param {Object} materialParams
       * @param {string} mapName
       * @param {Object} mapDef
       * @return {Promise<Texture>}
       */

    }, {
      key: "assignTexture",
      value: function assignTexture(materialParams, mapName, mapDef) {
        var parser = this;
        return this.getDependency('texture', mapDef.index).then(function (texture) {
          // Materials sample aoMap from UV set 1 and other maps from UV set 0 - this can't be configured
          // However, we will copy UV set 0 to UV set 1 on demand for aoMap
          if (mapDef.texCoord !== undefined && mapDef.texCoord != 0 && !(mapName === 'aoMap' && mapDef.texCoord == 1)) {
            console.warn('THREE.GLTFLoader: Custom UV set ' + mapDef.texCoord + ' for texture ' + mapName + ' not yet supported.');
          }

          if (parser.extensions[EXTENSIONS.KHR_TEXTURE_TRANSFORM]) {
            var transform = mapDef.extensions !== undefined ? mapDef.extensions[EXTENSIONS.KHR_TEXTURE_TRANSFORM] : undefined;

            if (transform) {
              var gltfReference = parser.associations.get(texture);
              texture = parser.extensions[EXTENSIONS.KHR_TEXTURE_TRANSFORM].extendTexture(texture, transform);
              parser.associations.set(texture, gltfReference);
            }
          }

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

    }, {
      key: "assignFinalMaterial",
      value: function assignFinalMaterial(mesh) {
        var geometry = mesh.geometry;
        var material = mesh.material;
        var useDerivativeTangents = geometry.attributes.tangent === undefined;
        var useVertexColors = geometry.attributes.color !== undefined;
        var useFlatShading = geometry.attributes.normal === undefined;

        if (mesh.isPoints) {
          var cacheKey = 'PointsMaterial:' + material.uuid;
          var pointsMaterial = this.cache.get(cacheKey);

          if (!pointsMaterial) {
            pointsMaterial = new _three.PointsMaterial();

            _three.Material.prototype.copy.call(pointsMaterial, material);

            pointsMaterial.color.copy(material.color);
            pointsMaterial.map = material.map;
            pointsMaterial.sizeAttenuation = false; // glTF spec says points should be 1px

            this.cache.add(cacheKey, pointsMaterial);
          }

          material = pointsMaterial;
        } else if (mesh.isLine) {
          var _cacheKey = 'LineBasicMaterial:' + material.uuid;

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

          if (!lineMaterial) {
            lineMaterial = new _three.LineBasicMaterial();

            _three.Material.prototype.copy.call(lineMaterial, material);

            lineMaterial.color.copy(material.color);
            this.cache.add(_cacheKey, lineMaterial);
          }

          material = lineMaterial;
        } // Clone the material if it will be modified


        if (useDerivativeTangents || useVertexColors || useFlatShading) {
          var _cacheKey2 = 'ClonedMaterial:' + material.uuid + ':';

          if (material.isGLTFSpecularGlossinessMaterial) _cacheKey2 += 'specular-glossiness:';
          if (useDerivativeTangents) _cacheKey2 += 'derivative-tangents:';
          if (useVertexColors) _cacheKey2 += 'vertex-colors:';
          if (useFlatShading) _cacheKey2 += 'flat-shading:';
          var cachedMaterial = this.cache.get(_cacheKey2);

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

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

            this.cache.add(_cacheKey2, cachedMaterial);
            this.associations.set(cachedMaterial, this.associations.get(material));
          }

          material = cachedMaterial;
        } // workarounds for mesh and geometry


        if (material.aoMap && geometry.attributes.uv2 === undefined && geometry.attributes.uv !== undefined) {
          geometry.setAttribute('uv2', geometry.attributes.uv);
        }

        mesh.material = material;
      }
    }, {
      key: "getMaterialType",
      value: function
        /* materialIndex */
      getMaterialType() {
        return _three.MeshStandardMaterial;
      }
      /**
       * Specification: https://github.com/KhronosGroup/glTF/blob/master/specification/2.0/README.md#materials
       * @param {number} materialIndex
       * @return {Promise<Material>}
       */

    }, {
      key: "loadMaterial",
      value: function loadMaterial(materialIndex) {
        var parser = this;
        var json = this.json;
        var extensions = this.extensions;
        var materialDef = json.materials[materialIndex];
        var materialType;
        var materialParams = {};
        var materialExtensions = materialDef.extensions || {};
        var pending = [];

        if (materialExtensions[EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS]) {
          var sgExtension = extensions[EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS];
          materialType = sgExtension.getMaterialType();
          pending.push(sgExtension.extendParams(materialParams, materialDef, parser));
        } else if (materialExtensions[EXTENSIONS.KHR_MATERIALS_UNLIT]) {
          var kmuExtension = extensions[EXTENSIONS.KHR_MATERIALS_UNLIT];
          materialType = kmuExtension.getMaterialType();
          pending.push(kmuExtension.extendParams(materialParams, materialDef, parser));
        } else {
          // Specification:
          // https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#metallic-roughness-material
          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));
          }

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

          if (metallicRoughness.metallicRoughnessTexture !== undefined) {
            pending.push(parser.assignTexture(materialParams, 'metalnessMap', metallicRoughness.metallicRoughnessTexture));
            pending.push(parser.assignTexture(materialParams, 'roughnessMap', metallicRoughness.metallicRoughnessTexture));
          }

          materialType = this._invokeOne(function (ext) {
            return ext.getMaterialType && ext.getMaterialType(materialIndex);
          });
          pending.push(Promise.all(this._invokeAll(function (ext) {
            return ext.extendMaterialParams && ext.extendMaterialParams(materialIndex, materialParams);
          })));
        }

        if (materialDef.doubleSided === true) {
          materialParams.side = _three.DoubleSide;
        }

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

        if (alphaMode === ALPHA_MODES.BLEND) {
          materialParams.transparent = true; // See: https://github.com/mrdoob/three.js/issues/17706

          materialParams.depthWrite = false;
        } else {
          materialParams.format = _three.RGBFormat;
          materialParams.transparent = false;

          if (alphaMode === ALPHA_MODES.MASK) {
            materialParams.alphaTest = materialDef.alphaCutoff !== undefined ? materialDef.alphaCutoff : 0.5;
          }
        }

        if (materialDef.normalTexture !== undefined && materialType !== _three.MeshBasicMaterial) {
          pending.push(parser.assignTexture(materialParams, 'normalMap', materialDef.normalTexture));
          materialParams.normalScale = new _three.Vector2(1, 1);

          if (materialDef.normalTexture.scale !== undefined) {
            var scale = materialDef.normalTexture.scale;
            materialParams.normalScale.set(scale, scale);
          }
        }

        if (materialDef.occlusionTexture !== undefined && materialType !== _three.MeshBasicMaterial) {
          pending.push(parser.assignTexture(materialParams, 'aoMap', materialDef.occlusionTexture));

          if (materialDef.occlusionTexture.strength !== undefined) {
            materialParams.aoMapIntensity = materialDef.occlusionTexture.strength;
          }
        }

        if (materialDef.emissiveFactor !== undefined && materialType !== _three.MeshBasicMaterial) {
          materialParams.emissive = new _three.Color().fromArray(materialDef.emissiveFactor);
        }

        if (materialDef.emissiveTexture !== undefined && materialType !== _three.MeshBasicMaterial) {
          pending.push(parser.assignTexture(materialParams, 'emissiveMap', materialDef.emissiveTexture));
        }

        return Promise.all(pending).then(function () {
          var material;

          if (materialType === GLTFMeshStandardSGMaterial) {
            material = extensions[EXTENSIONS.KHR_MATERIALS_PBR_SPECULAR_GLOSSINESS].createMaterial(materialParams);
          } else {
            material = new materialType(materialParams);
          }

          if (materialDef.name) material.name = materialDef.name; // baseColorTexture, emissiveTexture, and specularGlossinessTexture use sRGB encoding.

          if (material.map) material.map.encoding = _three.sRGBEncoding;
          if (material.emissiveMap) material.emissiveMap.encoding = _three.sRGBEncoding;
          assignExtrasToUserData(material, materialDef);
          parser.associations.set(material, {
            materials: materialIndex
          });
          if (materialDef.extensions) addUnknownExtensionsToUserData(extensions, material, materialDef);
          return material;
        });
      }
      /** When Object3D instances are targeted by animation, they need unique names. */

    }, {
      key: "createUniqueName",
      value: function createUniqueName(originalName) {
        var sanitizedName = _three.PropertyBinding.sanitizeNodeName(originalName || '');

        var name = sanitizedName;

        for (var i = 1; this.nodeNamesUsed[name]; ++i) {
          name = sanitizedName + '_' + i;
        }

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

    }, {
      key: "loadGeometries",
      value: function loadGeometries(primitives) {
        var parser = this;
        var extensions = this.extensions;
        var cache = this.primitiveCache;

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

        var pending = [];

        for (var i = 0, il = primitives.length; i < il; i++) {
          var primitive = primitives[i];
          var cacheKey = createPrimitiveKey(primitive); // See if we've already created this geometry

          var cached = cache[cacheKey];

          if (cached) {
            // Use the cached geometry if it exists
            pending.push(cached.promise);
          } else {
            var geometryPromise = void 0;

            if (primitive.extensions && primitive.extensions[EXTENSIONS.KHR_DRACO_MESH_COMPRESSION]) {
              // Use DRACO geometry if available
              geometryPromise = createDracoPrimitive(primitive);
            } else {
              // Otherwise create a new geometry
              geometryPromise = addPrimitiveAttributes(new _three.BufferGeometry(), primitive, parser);
            } // Cache this geometry


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

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

    }, {
      key: "loadMesh",
      value: function loadMesh(meshIndex) {
        var parser = this;
        var json = this.json;
        var extensions = this.extensions;
        var meshDef = json.meshes[meshIndex];
        var primitives = meshDef.primitives;
        var pending = [];

        for (var i = 0, il = primitives.length; i < il; i++) {
          var material = primitives[i].material === undefined ? createDefaultMaterial(this.cache) : this.getDependency('material', primitives[i].material);
          pending.push(material);
        }

        pending.push(parser.loadGeometries(primitives));
        return Promise.all(pending).then(function (results) {
          var materials = results.slice(0, results.length - 1);
          var geometries = results[results.length - 1];
          var meshes = [];

          for (var _i4 = 0, _il3 = geometries.length; _i4 < _il3; _i4++) {
            var geometry = geometries[_i4];
            var primitive = primitives[_i4]; // 1. create Mesh

            var mesh = void 0;
            var _material = materials[_i4];

            if (primitive.mode === WEBGL_CONSTANTS.TRIANGLES || primitive.mode === WEBGL_CONSTANTS.TRIANGLE_STRIP || primitive.mode === WEBGL_CONSTANTS.TRIANGLE_FAN || primitive.mode === undefined) {
              // .isSkinnedMesh isn't in glTF spec. See ._markDefs()
              mesh = meshDef.isSkinnedMesh === true ? new _three.SkinnedMesh(geometry, _material) : new _three.Mesh(geometry, _material);

              if (mesh.isSkinnedMesh === true && !mesh.geometry.attributes.skinWeight.normalized) {
                // we normalize floating point skin weight array to fix malformed assets (see #15319)
                // it's important to skip this for non-float32 data since normalizeSkinWeights assumes non-normalized inputs
                mesh.normalizeSkinWeights();
              }

              if (primitive.mode === WEBGL_CONSTANTS.TRIANGLE_STRIP) {
                mesh.geometry = toTrianglesDrawMode(mesh.geometry, _three.TriangleStripDrawMode);
              } else if (primitive.mode === WEBGL_CONSTANTS.TRIANGLE_FAN) {
                mesh.geometry = toTrianglesDrawMode(mesh.geometry, _three.TriangleFanDrawMode);
              }
            } else if (primitive.mode === WEBGL_CONSTANTS.LINES) {
              mesh = new _three.LineSegments(geometry, _material);
            } else if (primitive.mode === WEBGL_CONSTANTS.LINE_STRIP) {
              mesh = new _three.Line(geometry, _material);
            } else if (primitive.mode === WEBGL_CONSTANTS.LINE_LOOP) {
              mesh = new _three.LineLoop(geometry, _material);
            } else if (primitive.mode === WEBGL_CONSTANTS.POINTS) {
              mesh = new _three.Points(geometry, _material);
            } else {
              throw new Error('THREE.GLTFLoader: Primitive mode unsupported: ' + primitive.mode);
            }

            if (Object.keys(mesh.geometry.morphAttributes).length > 0) {
              updateMorphTargets(mesh, meshDef);
            }

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

          for (var _i5 = 0, _il4 = meshes.length; _i5 < _il4; _i5++) {
            parser.associations.set(meshes[_i5], {
              meshes: meshIndex,
              primitives: _i5
            });
          }

          if (meshes.length === 1) {
            return meshes[0];
          }

          var group = new _three.Group();
          parser.associations.set(group, {
            meshes: meshIndex
          });

          for (var _i6 = 0, _il5 = meshes.length; _i6 < _il5; _i6++) {
            group.add(meshes[_i6]);
          }

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

    }, {
      key: "loadCamera",
      value: function loadCamera(cameraIndex) {
        var camera;
        var cameraDef = this.json.cameras[cameraIndex];
        var params = cameraDef[cameraDef.type];

        if (!params) {
          console.warn('THREE.GLTFLoader: Missing camera parameters.');
          return;
        }

        if (cameraDef.type === 'perspective') {
          camera = new _three.PerspectiveCamera(_three.MathUtils.radToDeg(params.yfov), params.aspectRatio || 1, params.znear || 1, params.zfar || 2e6);
        } else if (cameraDef.type === 'orthographic') {
          camera = new _three.OrthographicCamera(-params.xmag, params.xmag, params.ymag, -params.ymag, params.znear, params.zfar);
        }

        if (cameraDef.name) camera.name = this.createUniqueName(cameraDef.name);
        assignExtrasToUserData(camera, cameraDef);
        return Promise.resolve(camera);
      }
      /**
       * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#skins
       * @param {number} skinIndex
       * @return {Promise<Object>}
       */

    }, {
      key: "loadSkin",
      value: function loadSkin(skinIndex) {
        var skinDef = this.json.skins[skinIndex];
        var skinEntry = {
          joints: skinDef.joints
        };

        if (skinDef.inverseBindMatrices === undefined) {
          return Promise.resolve(skinEntry);
        }

        return this.getDependency('accessor', skinDef.inverseBindMatrices).then(function (accessor) {
          skinEntry.inverseBindMatrices = accessor;
          return skinEntry;
        });
      }
      /**
       * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#animations
       * @param {number} animationIndex
       * @return {Promise<AnimationClip>}
       */

    }, {
      key: "loadAnimation",
      value: function loadAnimation(animationIndex) {
        var json = this.json;
        var animationDef = json.animations[animationIndex];
        var pendingNodes = [];
        var pendingInputAccessors = [];
        var pendingOutputAccessors = [];
        var pendingSamplers = [];
        var pendingTargets = [];

        for (var i = 0, il = animationDef.channels.length; i < il; i++) {
          var channel = animationDef.channels[i];
          var sampler = animationDef.samplers[channel.sampler];
          var target = channel.target;
          var name = target.node !== undefined ? target.node : target.id; // NOTE: target.id is deprecated.

          var input = animationDef.parameters !== undefined ? animationDef.parameters[sampler.input] : sampler.input;
          var output = animationDef.parameters !== undefined ? animationDef.parameters[sampler.output] : sampler.output;
          pendingNodes.push(this.getDependency('node', name));
          pendingInputAccessors.push(this.getDependency('accessor', input));
          pendingOutputAccessors.push(this.getDependency('accessor', output));
          pendingSamplers.push(sampler);
          pendingTargets.push(target);
        }

        return Promise.all([Promise.all(pendingNodes), Promise.all(pendingInputAccessors), Promise.all(pendingOutputAccessors), Promise.all(pendingSamplers), Promise.all(pendingTargets)]).then(function (dependencies) {
          var nodes = dependencies[0];
          var inputAccessors = dependencies[1];
          var outputAccessors = dependencies[2];
          var samplers = dependencies[3];
          var targets = dependencies[4];
          var tracks = [];

          var _loop = function _loop(_i7, _il6) {
            var node = nodes[_i7];
            var inputAccessor = inputAccessors[_i7];
            var outputAccessor = outputAccessors[_i7];
            var sampler = samplers[_i7];
            var target = targets[_i7];
            if (node === undefined) return "continue";
            node.updateMatrix();
            node.matrixAutoUpdate = true;
            var TypedKeyframeTrack = void 0;

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

            if (PATH_PROPERTIES[target.path] === PATH_PROPERTIES.weights) {
              node.traverse(function (object) {
                if (object.morphTargetInfluences) {
                  targetNames.push(object.name ? object.name : object.uuid);
                }
              });
            } else {
              targetNames.push(targetName);
            }

            var outputArray = outputAccessor.array;

            if (outputAccessor.normalized) {
              var scale = getNormalizedComponentScale(outputArray.constructor);
              var scaled = new Float32Array(outputArray.length);

              for (var j = 0, jl = outputArray.length; j < jl; j++) {
                scaled[j] = outputArray[j] * scale;
              }

              outputArray = scaled;
            }

            for (var _j = 0, _jl = targetNames.length; _j < _jl; _j++) {
              var track = new TypedKeyframeTrack(targetNames[_j] + '.' + PATH_PROPERTIES[target.path], inputAccessor.array, outputArray, interpolation); // Override interpolation with custom factory method.

              if (sampler.interpolation === 'CUBICSPLINE') {
                track.createInterpolant = function InterpolantFactoryMethodGLTFCubicSpline(result) {
                  // A CUBICSPLINE keyframe in glTF has three output values for each input value,
                  // representing inTangent, splineVertex, and outTangent. As a result, track.getValueSize()
                  // must be divided by three to get the interpolant's sampleSize argument.
                  var interpolantType = this instanceof _three.QuaternionKeyframeTrack ? GLTFCubicSplineQuaternionInterpolant : GLTFCubicSplineInterpolant;
                  return new interpolantType(this.times, this.values, this.getValueSize() / 3, result);
                }; // Mark as CUBICSPLINE. `track.getInterpolation()` doesn't support custom interpolants.


                track.createInterpolant.isInterpolantFactoryMethodGLTFCubicSpline = true;
              }

              tracks.push(track);
            }
          };

          for (var _i7 = 0, _il6 = nodes.length; _i7 < _il6; _i7++) {
            var _ret = _loop(_i7, _il6);

            if (_ret === "continue") continue;
          }

          var name = animationDef.name ? animationDef.name : 'animation_' + animationIndex;
          return new _three.AnimationClip(name, undefined, tracks);
        });
      }
    }, {
      key: "createNodeMesh",
      value: function createNodeMesh(nodeIndex) {
        var json = this.json;
        var parser = this;
        var nodeDef = json.nodes[nodeIndex];
        if (nodeDef.mesh === undefined) return null;
        return parser.getDependency('mesh', nodeDef.mesh).then(function (mesh) {
          var node = parser._getNodeRef(parser.meshCache, nodeDef.mesh, mesh); // if weights are provided on the node, override weights on the mesh.


          if (nodeDef.weights !== undefined) {
            node.traverse(function (o) {
              if (!o.isMesh) return;

              for (var i = 0, il = nodeDef.weights.length; i < il; i++) {
                o.morphTargetInfluences[i] = nodeDef.weights[i];
              }
            });
          }

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

    }, {
      key: "loadNode",
      value: function loadNode(nodeIndex) {
        var json = this.json;
        var extensions = this.extensions;
        var parser = this;
        var nodeDef = json.nodes[nodeIndex]; // reserve node's name before its dependencies, so the root has the intended name.

        var nodeName = nodeDef.name ? parser.createUniqueName(nodeDef.name) : '';
        return function () {
          var pending = [];

          var meshPromise = parser._invokeOne(function (ext) {
            return ext.createNodeMesh && ext.createNodeMesh(nodeIndex);
          });

          if (meshPromise) {
            pending.push(meshPromise);
          }

          if (nodeDef.camera !== undefined) {
            pending.push(parser.getDependency('camera', nodeDef.camera).then(function (camera) {
              return parser._getNodeRef(parser.cameraCache, nodeDef.camera, camera);
            }));
          }

          parser._invokeAll(function (ext) {
            return ext.createNodeAttachment && ext.createNodeAttachment(nodeIndex);
          }).forEach(function (promise) {
            pending.push(promise);
          });

          return Promise.all(pending);
        }().then(function (objects) {
          var node; // .isBone isn't in glTF spec. See ._markDefs

          if (nodeDef.isBone === true) {
            node = new _three.Bone();
          } else if (objects.length > 1) {
            node = new _three.Group();
          } else if (objects.length === 1) {
            node = objects[0];
          } else {
            node = new _three.Object3D();
          }

          if (node !== objects[0]) {
            for (var i = 0, il = objects.length; i < il; i++) {
              node.add(objects[i]);
            }
          }

          if (nodeDef.name) {
            node.userData.name = nodeDef.name;
            node.name = nodeName;
          }

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

          if (nodeDef.matrix !== undefined) {
            var matrix = new _three.Matrix4();
            matrix.fromArray(nodeDef.matrix);
            node.applyMatrix4(matrix);
          } else {
            if (nodeDef.translation !== undefined) {
              node.position.fromArray(nodeDef.translation);
            }

            if (nodeDef.rotation !== undefined) {
              node.quaternion.fromArray(nodeDef.rotation);
            }

            if (nodeDef.scale !== undefined) {
              node.scale.fromArray(nodeDef.scale);
            }
          }

          if (!parser.associations.has(node)) {
            parser.associations.set(node, {});
          }

          parser.associations.get(node).nodes = nodeIndex;
          return node;
        });
      }
      /**
       * Specification: https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#scenes
       * @param {number} sceneIndex
       * @return {Promise<Group>}
       */

    }, {
      key: "loadScene",
      value: function loadScene(sceneIndex) {
        var json = this.json;
        var extensions = this.extensions;
        var sceneDef = this.json.scenes[sceneIndex];
        var parser = this; // Loader returns Group, not Scene.
        // See: https://github.com/mrdoob/three.js/issues/18342#issuecomment-578981172

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

        for (var i = 0, il = nodeIds.length; i < il; i++) {
          pending.push(buildNodeHierarchy(nodeIds[i], scene, json, parser));
        }

        return Promise.all(pending).then(function () {
          // Removes dangling associations, associations that reference a node that
          // didn't make it into the scene.
          var reduceAssociations = function reduceAssociations(node) {
            var reducedAssociations = new Map();

            var _iterator2 = _createForOfIteratorHelper(parser.associations),
                _step2;

            try {
              for (_iterator2.s(); !(_step2 = _iterator2.n()).done;) {
                var _step2$value = _slicedToArray(_step2.value, 2),
                    key = _step2$value[0],
                    value = _step2$value[1];

                if (key instanceof _three.Material || key instanceof _three.Texture) {
                  reducedAssociations.set(key, value);
                }
              }
            } catch (err) {
              _iterator2.e(err);
            } finally {
              _iterator2.f();
            }

            node.traverse(function (node) {
              var mappings = parser.associations.get(node);

              if (mappings != null) {
                reducedAssociations.set(node, mappings);
              }
            });
            return reducedAssociations;
          };

          parser.associations = reduceAssociations(scene);
          return scene;
        });
      }
    }]);

    return GLTFParser;
  }();

  function buildNodeHierarchy(nodeId, parentObject, json, parser) {
    var nodeDef = json.nodes[nodeId];
    return parser.getDependency('node', nodeId).then(function (node) {
      if (nodeDef.skin === undefined) return node; // build skeleton here as well

      var skinEntry;
      return parser.getDependency('skin', nodeDef.skin).then(function (skin) {
        skinEntry = skin;
        var pendingJoints = [];

        for (var i = 0, il = skinEntry.joints.length; i < il; i++) {
          pendingJoints.push(parser.getDependency('node', skinEntry.joints[i]));
        }

        return Promise.all(pendingJoints);
      }).then(function (jointNodes) {
        node.traverse(function (mesh) {
          if (!mesh.isMesh) return;
          var bones = [];
          var boneInverses = [];

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

            if (jointNode) {
              bones.push(jointNode);
              var mat = new _three.Matrix4();

              if (skinEntry.inverseBindMatrices !== undefined) {
                mat.fromArray(skinEntry.inverseBindMatrices.array, j * 16);
              }

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

          mesh.bind(new _three.Skeleton(bones, boneInverses), mesh.matrixWorld);
        });
        return node;
      });
    }).then(function (node) {
      // build node hierachy
      parentObject.add(node);
      var pending = [];

      if (nodeDef.children) {
        var children = nodeDef.children;

        for (var i = 0, il = children.length; i < il; i++) {
          var child = children[i];
          pending.push(buildNodeHierarchy(child, node, json, parser));
        }
      }

      return Promise.all(pending);
    });
  }
  /**
   * @param {BufferGeometry} geometry
   * @param {GLTF.Primitive} primitiveDef
   * @param {GLTFParser} parser
   */


  function computeBounds(geometry, primitiveDef, parser) {
    var attributes = primitiveDef.attributes;
    var box = new _three.Box3();

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

      if (min !== undefined && max !== undefined) {
        box.set(new _three.Vector3(min[0], min[1], min[2]), new _three.Vector3(max[0], max[1], max[2]));

        if (accessor.normalized) {
          var boxScale = getNormalizedComponentScale(WEBGL_COMPONENT_TYPES[accessor.componentType]);
          box.min.multiplyScalar(boxScale);
          box.max.multiplyScalar(boxScale);
        }
      } else {
        console.warn('THREE.GLTFLoader: Missing min/max properties for accessor POSITION.');
        return;
      }
    } else {
      return;
    }

    var targets = primitiveDef.targets;

    if (targets !== undefined) {
      var maxDisplacement = new _three.Vector3();
      var vector = new _three.Vector3();

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

        if (target.POSITION !== undefined) {
          var _accessor = parser.json.accessors[target.POSITION];
          var _min = _accessor.min;
          var _max = _accessor.max; // glTF requires 'min' and 'max', but VRM (which extends glTF) currently ignores that requirement.

          if (_min !== undefined && _max !== undefined) {
            // we need to get max of absolute components because target weight is [-1,1]
            vector.setX(Math.max(Math.abs(_min[0]), Math.abs(_max[0])));
            vector.setY(Math.max(Math.abs(_min[1]), Math.abs(_max[1])));
            vector.setZ(Math.max(Math.abs(_min[2]), Math.abs(_max[2])));

            if (_accessor.normalized) {
              var _boxScale = getNormalizedComponentScale(WEBGL_COMPONENT_TYPES[_accessor.componentType]);

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


            maxDisplacement.max(vector);
          } else {
            console.warn('THREE.GLTFLoader: Missing min/max properties for accessor POSITION.');
          }
        }
      } // As per comment above this box isn't conservative, but has a reasonable size for a very large number of morph targets.


      box.expandByVector(maxDisplacement);
    }

    geometry.boundingBox = box;
    var sphere = new _three.Sphere();
    box.getCenter(sphere.center);
    sphere.radius = box.min.distanceTo(box.max) / 2;
    geometry.boundingSphere = sphere;
  }
  /**
   * @param {BufferGeometry} geometry
   * @param {GLTF.Primitive} primitiveDef
   * @param {GLTFParser} parser
   * @return {Promise<BufferGeometry>}
   */


  function addPrimitiveAttributes(geometry, primitiveDef, parser) {
    var attributes = primitiveDef.attributes;
    var pending = [];

    function assignAttributeAccessor(accessorIndex, attributeName) {
      return parser.getDependency('accessor', accessorIndex).then(function (accessor) {
        geometry.setAttribute(attributeName, accessor);
      });
    }

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

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

    if (primitiveDef.indices !== undefined && !geometry.index) {
      var accessor = parser.getDependency('accessor', primitiveDef.indices).then(function (accessor) {
        geometry.setIndex(accessor);
      });
      pending.push(accessor);
    }

    assignExtrasToUserData(geometry, primitiveDef);
    computeBounds(geometry, primitiveDef, parser);
    return Promise.all(pending).then(function () {
      return primitiveDef.targets !== undefined ? addMorphTargets(geometry, primitiveDef.targets, parser) : geometry;
    });
  }
  /**
   * @param {BufferGeometry} geometry
   * @param {Number} drawMode
   * @return {BufferGeometry}
   */


  function toTrianglesDrawMode(geometry, drawMode) {
    var index = geometry.getIndex(); // generate index if not present

    if (index === null) {
      var indices = [];
      var position = geometry.getAttribute('position');

      if (position !== undefined) {
        for (var i = 0; i < position.count; i++) {
          indices.push(i);
        }

        geometry.setIndex(indices);
        index = geometry.getIndex();
      } else {
        console.error('THREE.GLTFLoader.toTrianglesDrawMode(): Undefined position attribute. Processing not possible.');
        return geometry;
      }
    } //


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

    if (drawMode === _three.TriangleFanDrawMode) {
      // gl.TRIANGLE_FAN
      for (var _i8 = 1; _i8 <= numberOfTriangles; _i8++) {
        newIndices.push(index.getX(0));
        newIndices.push(index.getX(_i8));
        newIndices.push(index.getX(_i8 + 1));
      }
    } else {
      // gl.TRIANGLE_STRIP
      for (var _i9 = 0; _i9 < numberOfTriangles; _i9++) {
        if (_i9 % 2 === 0) {
          newIndices.push(index.getX(_i9));
          newIndices.push(index.getX(_i9 + 1));
          newIndices.push(index.getX(_i9 + 2));
        } else {
          newIndices.push(index.getX(_i9 + 2));
          newIndices.push(index.getX(_i9 + 1));
          newIndices.push(index.getX(_i9));
        }
      }
    }

    if (newIndices.length / 3 !== numberOfTriangles) {
      console.error('THREE.GLTFLoader.toTrianglesDrawMode(): Unable to generate correct amount of triangles.');
    } // build final geometry


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