text: /* jshint wsh:true */
  /**
  * @author       Richard Davey <rich@photonstorm.com>
  * @copyright    2016 Photon Storm Ltd.
  * @license      {@link https://github.com/photonstorm/phaser/blob/master/license.txt|MIT License}
  */
  
  /**
  * The Loader handles loading all external content such as Images, Sounds, Texture Atlases and data files.
  *
  * The loader uses a combination of tag loading (eg. Image elements) and XHR and provides progress and completion callbacks.
  *
  * Parallel loading (see {@link #enableParallel}) is supported and enabled by default.
  * Load-before behavior of parallel resources is controlled by synchronization points as discussed in {@link #withSyncPoint}.
  *
  * Texture Atlases can be created with tools such as [Texture Packer](https://www.codeandweb.com/texturepacker/phaser) and
  * [Shoebox](http://renderhjs.net/shoebox/)
  *
  * @class Phaser.Loader
  * @param {Phaser.Game} game - A reference to the currently running game.
  */
  Phaser.Loader = function (game) {
  
      /**
      * Local reference to game.
      * @property {Phaser.Game} game
      * @protected
      */
      this.game = game;
  
      /**
      * Local reference to the Phaser.Cache.
      * @property {Phaser.Cache} cache
      * @protected
      */
      this.cache = game.cache;
  
      /**
      * If true all calls to Loader.reset will be ignored. Useful if you need to create a load queue before swapping to a preloader state.
      * @property {boolean} resetLocked
      * @default
      */
      this.resetLocked = false;
  
      /**
      * True if the Loader is in the process of loading the queue.
      * @property {boolean} isLoading
      * @default
      */
      this.isLoading = false;
  
      /**
      * True if all assets in the queue have finished loading.
      * @property {boolean} hasLoaded
      * @default
      */
      this.hasLoaded = false;
  
      /**
      * You can optionally link a progress sprite with {@link Phaser.Loader#setPreloadSprite setPreloadSprite}.
      *
      * This property is an object containing: sprite, rect, direction, width and height
      *
      * @property {?object} preloadSprite
      * @protected
      */
      this.preloadSprite = null;
  
      /**
      * The crossOrigin value applied to loaded images. Very often this needs to be set to 'anonymous'.
      * @property {boolean|string} crossOrigin
      * @default
      */
      this.crossOrigin = false;
  
      /**
      * If you want to append a URL before the path of any asset you can set this here.
      * Useful if allowing the asset base url to be configured outside of the game code.
      * The string _must_ end with a "/".
      *
      * @property {string} baseURL
      */
      this.baseURL = '';
  
      /**
      * The value of `path`, if set, is placed before any _relative_ file path given. For example:
      *
      * `load.path = "images/sprites/";
      * load.image("ball", "ball.png");
      * load.image("tree", "level1/oaktree.png");
      * load.image("boom", "http://server.com/explode.png");`
      *
      * Would load the `ball` file from `images/sprites/ball.png` and the tree from
      * `images/sprites/level1/oaktree.png` but the file `boom` would load from the URL
      * given as it's an absolute URL.
      *
      * Please note that the path is added before the filename but *after* the baseURL (if set.)
      *
      * The string _must_ end with a "/".
      *
      * @property {string} path
      */
      this.path = '';
  
      /**
      * Used to map the application mime-types to to the Accept header in XHR requests.
      * If you don't require these mappings, or they cause problems on your server, then
      * remove them from the headers object and the XHR request will not try to use them.
      *
      * This object can also be used to set the `X-Requested-With` header to 
      * `XMLHttpRequest` (or any other value you need). To enable this do:
      *
      * `this.load.headers.requestedWith = 'XMLHttpRequest'`
      *
      * before adding anything to the Loader. The XHR loader will then call:
      *
      * `setRequestHeader('X-Requested-With', this.headers['requestedWith'])`
      * 
      * @property {object} headers
      * @default
      */
      this.headers = {
          "requestedWith": false,
          "json": "application/json",
          "xml": "application/xml"
      };
  
      /**
       * This event is dispatched when the loading process starts: before the first file has been requested,
      * but after all the initial packs have been loaded.
      *
      * @property {Phaser.Signal} onLoadStart
      */
      this.onLoadStart = new Phaser.Signal();
  
      /**
      * This event is dispatched when the final file in the load queue has either loaded or failed.
      *
      * @property {Phaser.Signal} onLoadComplete
      */
      this.onLoadComplete = new Phaser.Signal();
  
      /**
      * This event is dispatched when an asset pack has either loaded or failed to load.
      *
      * This is called when the asset pack manifest file has loaded and successfully added its contents to the loader queue.
      *
      * Params: `(pack key, success?, total packs loaded, total packs)`
      *
      * @property {Phaser.Signal} onPackComplete
      */
      this.onPackComplete = new Phaser.Signal();
  
      /**
      * This event is dispatched immediately before a file starts loading.
      * It's possible the file may fail (eg. download error, invalid format) after this event is sent.
      *
      * Params: `(progress, file key, file url)`
      *
      * @property {Phaser.Signal} onFileStart
      */
      this.onFileStart = new Phaser.Signal();
  
      /**
      * This event is dispatched when a file has either loaded or failed to load.
      *
      * Any function bound to this will receive the following parameters:
      *
      * progress, file key, success?, total loaded files, total files
      *
      * Where progress is a number between 1 and 100 (inclusive) representing the percentage of the load.
      *
      * @property {Phaser.Signal} onFileComplete
      */
      this.onFileComplete = new Phaser.Signal();
  
      /**
      * This event is dispatched when a file (or pack) errors as a result of the load request.
      *
      * For files it will be triggered before `onFileComplete`. For packs it will be triggered before `onPackComplete`.
      *
      * Params: `(file key, file)`
      *
      * @property {Phaser.Signal} onFileError
      */
      this.onFileError = new Phaser.Signal();
  
      /**
      * If true and if the browser supports XDomainRequest, it will be used in preference for XHR.
      *
      * This is only relevant for IE 9 and should _only_ be enabled for IE 9 clients when required by the server/CDN.
      *
      * @property {boolean} useXDomainRequest
      * @deprecated This is only relevant for IE 9.
      */
      this.useXDomainRequest = false;
  
      /**
      * @private
      * @property {boolean} _warnedAboutXDomainRequest - Control number of warnings for using XDR outside of IE 9.
      */
      this._warnedAboutXDomainRequest = false;
  
      /**
      * If true (the default) then parallel downloading will be enabled.
      *
      * To disable all parallel downloads this must be set to false prior to any resource being loaded.
      *
      * @property {boolean} enableParallel
      */
      this.enableParallel = true;
  
      /**
      * The number of concurrent / parallel resources to try and fetch at once.
      *
      * Many current browsers limit 6 requests per domain; this is slightly conservative.
      *
      * @property {integer} maxParallelDownloads
      * @protected
      */
      this.maxParallelDownloads = 4;
  
      /**
      * A counter: if more than zero, files will be automatically added as a synchronization point.
      * @property {integer} _withSyncPointDepth;
      */
      this._withSyncPointDepth = 0;
  
      /**
      * Contains all the information for asset files (including packs) to load.
      *
      * File/assets are only removed from the list after all loading completes.
      *
      * @property {file[]} _fileList
      * @private
      */
      this._fileList = [];
  
      /**
      * Inflight files (or packs) that are being fetched/processed.
      *
      * This means that if there are any files in the flight queue there should still be processing
      * going on; it should only be empty before or after loading.
      *
      * The files in the queue may have additional properties added to them,
      * including `requestObject` which is normally the associated XHR.
      *
      * @property {file[]} _flightQueue
      * @private
      */
      this._flightQueue = [];
  
      /**
      * The offset into the fileList past all the complete (loaded or error) entries.
      *
      * @property {integer} _processingHead
      * @private
      */
      this._processingHead = 0;
  
      /**
      * True when the first file (not pack) has loading started.
      * This used to to control dispatching `onLoadStart` which happens after any initial packs are loaded.
      *
      * @property {boolean} _initialPacksLoaded
      * @private
      */
      this._fileLoadStarted = false;
  
      /**
      * Total packs seen - adjusted when a pack is added.
      * @property {integer} _totalPackCount
      * @private
      */
      this._totalPackCount = 0;
  
      /**
      * Total files seen - adjusted when a file is added.
      * @property {integer} _totalFileCount
      * @private
      */
      this._totalFileCount = 0;
  
      /**
      * Total packs loaded - adjusted just prior to `onPackComplete`.
      * @property {integer} _loadedPackCount
      * @private
      */
      this._loadedPackCount = 0;
  
      /**
      * Total files loaded - adjusted just prior to `onFileComplete`.
      * @property {integer} _loadedFileCount
      * @private
      */
      this._loadedFileCount = 0;
  
  };
  
  /**
  * @constant
  * @type {number}
  */
  Phaser.Loader.TEXTURE_ATLAS_JSON_ARRAY = 0;
  
  /**
  * @constant
  * @type {number}
  */
  Phaser.Loader.TEXTURE_ATLAS_JSON_HASH = 1;
  
  /**
  * @constant
  * @type {number}
  */
  Phaser.Loader.TEXTURE_ATLAS_XML_STARLING = 2;
  
  /**
  * @constant
  * @type {number}
  */
  Phaser.Loader.PHYSICS_LIME_CORONA_JSON = 3;
  
  /**
  * @constant
  * @type {number}
  */
  Phaser.Loader.PHYSICS_PHASER_JSON = 4;
  
  /**
  * @constant
  * @type {number}
  */
  Phaser.Loader.TEXTURE_ATLAS_JSON_PYXEL = 5;
  
  Phaser.Loader.prototype = {
  
      /**
      * Set a Sprite to be a "preload" sprite by passing it to this method.
      *
      * A "preload" sprite will have its width or height crop adjusted based on the percentage of the loader in real-time.
      * This allows you to easily make loading bars for games.
      *
      * The sprite will automatically be made visible when calling this.
      *
      * @method Phaser.Loader#setPreloadSprite
      * @param {Phaser.Sprite|Phaser.Image} sprite - The sprite or image that will be cropped during the load.
      * @param {number} [direction=0] - A value of zero means the sprite will be cropped horizontally, a value of 1 means its will be cropped vertically.
      */
      setPreloadSprite: function (sprite, direction) {
  
          direction = direction || 0;
  
          this.preloadSprite = { sprite: sprite, direction: direction, width: sprite.width, height: sprite.height, rect: null };
  
          if (direction === 0)
          {
              //  Horizontal rect
              this.preloadSprite.rect = new Phaser.Rectangle(0, 0, 1, sprite.height);
          }
          else
          {
              //  Vertical rect
              this.preloadSprite.rect = new Phaser.Rectangle(0, 0, sprite.width, 1);
          }
  
          sprite.crop(this.preloadSprite.rect);
  
          sprite.visible = true;
  
      },
  
      /**
      * Called automatically by ScaleManager when the game resizes in RESIZE scalemode.
      *
      * This can be used to adjust the preloading sprite size, eg.
      *
      * @method Phaser.Loader#resize
      * @protected
      */
      resize: function () {
  
          if (this.preloadSprite && this.preloadSprite.height !== this.preloadSprite.sprite.height)
          {
              this.preloadSprite.rect.height = this.preloadSprite.sprite.height;
          }
  
      },
  
      /**
      * Check whether a file/asset with a specific key is queued to be loaded.
      *
      * To access a loaded asset use Phaser.Cache, eg. {@link Phaser.Cache#checkImageKey}
      *
      * @method Phaser.Loader#checkKeyExists
      * @param {string} type - The type asset you want to check.
      * @param {string} key - Key of the asset you want to check.
      * @return {boolean} Return true if exists, otherwise return false.
      */
      checkKeyExists: function (type, key) {
  
          return this.getAssetIndex(type, key) > -1;
  
      },
  
      /**
      * Get the queue-index of the file/asset with a specific key.
      *
      * Only assets in the download file queue will be found.
      *
      * @method Phaser.Loader#getAssetIndex
      * @param {string} type - The type asset you want to check.
      * @param {string} key - Key of the asset you want to check.
      * @return {number} The index of this key in the filelist, or -1 if not found.
      *     The index may change and should only be used immediately following this call
      */
      getAssetIndex: function (type, key) {
  
          var bestFound = -1;
  
          for (var i = 0; i < this._fileList.length; i++)
          {
              var file = this._fileList[i];
  
              if (file.type === type && file.key === key)
              {
                  bestFound = i;
  
                  // An already loaded/loading file may be superceded.
                  if (!file.loaded && !file.loading)
                  {
                      break;
                  }
              }
          }
  
          return bestFound;
  
      },
  
      /**
      * Find a file/asset with a specific key.
      *
      * Only assets in the download file queue will be found.
      *
      * @method Phaser.Loader#getAsset
      * @param {string} type - The type asset you want to check.
      * @param {string} key - Key of the asset you want to check.
      * @return {any} Returns an object if found that has 2 properties: `index` and `file`; otherwise a non-true value is returned.
      *     The index may change and should only be used immediately following this call.
      */
      getAsset: function (type, key) {
  
          var fileIndex = this.getAssetIndex(type, key);
  
          if (fileIndex > -1)
          {
              return { index: fileIndex, file: this._fileList[fileIndex] };
          }
  
          return false;
  
      },
  
      /**
      * Reset the loader and clear any queued assets. If `Loader.resetLocked` is true this operation will abort.
      *
      * This will abort any loading and clear any queued assets.
      *
      * Optionally you can clear any associated events.
      *
      * @method Phaser.Loader#reset
      * @protected
      * @param {boolean} [hard=false] - If true then the preload sprite and other artifacts may also be cleared.
      * @param {boolean} [clearEvents=false] - If true then the all Loader signals will have removeAll called on them.
      */
      reset: function (hard, clearEvents) {
  
          if (clearEvents === undefined) { clearEvents = false; }
  
          if (this.resetLocked)
          {
              return;
          }
  
          if (hard)
          {
              this.preloadSprite = null;
          }
  
          this.isLoading = false;
  
          this._processingHead = 0;
          this._fileList.length = 0;
          this._flightQueue.length = 0;
  
          this._fileLoadStarted = false;
          this._totalFileCount = 0;
          this._totalPackCount = 0;
          this._loadedPackCount = 0;
          this._loadedFileCount = 0;
  
          if (clearEvents)
          {
              this.onLoadStart.removeAll();
              this.onLoadComplete.removeAll();
              this.onPackComplete.removeAll();
              this.onFileStart.removeAll();
              this.onFileComplete.removeAll();
              this.onFileError.removeAll();
          }
  
      },
  
      /**
      * Internal function that adds a new entry to the file list. Do not call directly.
      *
      * @method Phaser.Loader#addToFileList
      * @protected
      * @param {string} type - The type of resource to add to the list (image, audio, xml, etc).
      * @param {string} key - The unique Cache ID key of this resource.
      * @param {string} [url] - The URL the asset will be loaded from.
      * @param {object} [properties=(none)] - Any additional properties needed to load the file. These are added directly to the added file object and overwrite any defaults.
      * @param {boolean} [overwrite=false] - If true then this will overwrite a file asset of the same type/key. Otherwise it will only add a new asset. If overwrite is true, and the asset is already being loaded (or has been loaded), then it is appended instead.
      * @param {string} [extension] - If no URL is given the Loader will sometimes auto-generate the URL based on the key, using this as the extension.
      * @return {Phaser.Loader} This instance of the Phaser Loader.
      */
      addToFileList: function (type, key, url, properties, overwrite, extension) {
  
          if (overwrite === undefined) { overwrite = false; }
  
          if (key === undefined || key === '')
          {
              console.warn("Phaser.Loader: Invalid or no key given of type " + type);
              return this;
          }
  
          if (url === undefined || url === null)
          {
              if (extension)
              {
                  url = key + extension;
              }
              else
              {
                  console.warn("Phaser.Loader: No URL given for file type: " + type + " key: " + key);
                  return this;
              }
          }
  
          var file = {
              type: type,
              key: key,
              path: this.path,
              url: url,
              syncPoint: this._withSyncPointDepth > 0,
              data: null,
              loading: false,
              loaded: false,
              error: false
          };
  
          if (properties)
          {
              for (var prop in properties)
              {
                  file[prop] = properties[prop];
              }
          }
  
          var fileIndex = this.getAssetIndex(type, key);
  
          if (overwrite && fileIndex > -1)
          {
              var currentFile = this._fileList[fileIndex];
  
              if (!currentFile.loading && !currentFile.loaded)
              {
                  this._fileList[fileIndex] = file;
              }
              else
              {
                  this._fileList.push(file);
                  this._totalFileCount++;
              }
          }
          else if (fileIndex === -1)
          {
              this._fileList.push(file);
              this._totalFileCount++;
          }
  
          return this;
  
      },
  
      /**
      * Internal function that replaces an existing entry in the file list with a new one. Do not call directly.
      *
      * @method Phaser.Loader#replaceInFileList
      * @protected
      * @param {string} type - The type of resource to add to the list (image, audio, xml, etc).
      * @param {string} key - The unique Cache ID key of this resource.
      * @param {string} url - The URL the asset will be loaded from.
      * @param {object} properties - Any additional properties needed to load the file.
      */
      replaceInFileList: function (type, key, url, properties) {
  
          return this.addToFileList(type, key, url, properties, true);
  
      },
  
      /**
      * Add a JSON resource pack ('packfile') to the Loader.
      *
      * A packfile is a JSON file that contains a list of assets to the be loaded.
      * Please see the example 'loader/asset pack' in the Phaser Examples repository.
      *
      * Packs are always put before the first non-pack file that is not loaded / loading.
      *
      * This means that all packs added before any loading has started are added to the front
      * of the file queue, in the order added.
      *
      * The key must be a unique String. It is used to add the file to the Phaser.Cache upon successful load.
      *
      * The URL of the packfile can be relative or absolute. If the URL is relative the `Loader.baseURL` and `Loader.path` values will be prepended to it.
      *
      * @method Phaser.Loader#pack
      * @param {string} key - Unique asset key of this resource pack.
      * @param {string} [url] - URL of the Asset Pack JSON file. If you wish to pass a json object instead set this to null and pass the object as the data parameter.
      * @param {object} [data] - The Asset Pack JSON data. Use this to pass in a json data object rather than loading it from a URL. TODO
      * @param {object} [callbackContext=(loader)] - Some Loader operations, like Binary and Script require a context for their callbacks. Pass the context here.
      * @return {Phaser.Loader} This Loader instance.
      */
      pack: function (key, url, data, callbackContext) {
  
          if (url === undefined) { url = null; }
          if (data === undefined) { data = null; }
          if (callbackContext === undefined) { callbackContext = null; }
  
          if (!url && !data)
          {
              console.warn('Phaser.Loader.pack - Both url and data are null. One must be set.');
  
              return this;
          }
  
          var pack = {
              type: 'packfile',
              key: key,
              url: url,
              path: this.path,
              syncPoint: true,
              data: null,
              loading: false,
              loaded: false,
              error: false,
              callbackContext: callbackContext
          };
  
          //  A data object has been given
          if (data)
          {
              if (typeof data === 'string')
              {
                  data = JSON.parse(data);
              }
  
              pack.data = data || {};
  
              //  Already consider 'loaded'
              pack.loaded = true;
          }
  
          // Add before first non-pack/no-loaded ~ last pack from start prior to loading
          // (Read one past for splice-to-end)
          for (var i = 0; i < this._fileList.length + 1; i++)
          {
              var file = this._fileList[i];
  
              if (!file || (!file.loaded && !file.loading && file.type !== 'packfile'))
              {
                  this._fileList.splice(i, 0, pack);
                  this._totalPackCount++;
                  break;
              }
          }
  
          return this;
  
      },
  
      /**
      * Adds an Image to the current load queue.
      *
      * The file is **not** loaded immediately after calling this method. The file is added to the queue ready to be loaded when the loader starts.
      *
      * Phaser can load all common image types: png, jpg, gif and any other format the browser can natively handle.
      *
      * The key must be a unique String. It is used to add the file to the Phaser.Cache upon successful load.
      *
      * Retrieve the image via `Cache.getImage(key)`
      *
      * The URL can be relative or absolute. If the URL is relative the `Loader.baseURL` and `Loader.path` values will be prepended to it.
      *
      * If the URL isn't specified the Loader will take the key and create a filename from that. For example if the key is "alien"
      * and no URL is given then the Loader will set the URL to be "alien.png". It will always add `.png` as the extension.
      * If you do not desire this action then provide a URL.
      *
      * This method also supports passing in a texture object as the `url` argument. This allows you to load
      * compressed textures into Phaser. You can also use `Loader.texture` to do this.
      * 
      * Compressed Textures are a WebGL only feature, and require 3rd party tools to create.
      * Available tools include Texture Packer, PVRTexTool, DirectX Texture Tool and Mali Texture Compression Tool.
      *
      * Supported texture compression formats are: PVRTC, S3TC and ETC1.
      * Supported file formats are: PVR, DDS, KTX and PKM.
      *
      * The formats that support all 3 compression algorithms are PVR and KTX.
      * PKM only supports ETC1, and DDS only S3TC for now.
      *
      * The texture path object looks like this:
      *
      * ```
      * load.image('factory', {
      *     etc1: 'assets/factory_etc1.pkm',
      *     s3tc: 'assets/factory_dxt1.pvr',
      *     pvrtc: 'assets/factory_pvrtc.pvr',
      *     truecolor: 'assets/factory.png'
      * });
      * ```
      * 
      * The `truecolor` property points to a standard PNG file, that will be used if none of the 
      * compressed formats are supported by the browser / GPU.
      *
      * @method Phaser.Loader#image
      * @param {string} key - Unique asset key of this image file.
      * @param {string|object} [url] - URL of an image file. If undefined or `null` the url will be set to `<key>.png`, i.e. if `key` was "alien" then the URL will be "alien.png". Can also be a texture data object.
      * @param {boolean} [overwrite=false] - If an unloaded file with a matching key already exists in the queue, this entry will overwrite it.
      * @return {Phaser.Loader} This Loader instance.
      */
      image: function (key, url, overwrite) {
  
          if (typeof url === 'object')
          {
              return this.texture(key, url, overwrite);
          }
          else
          {
              return this.addToFileList('image', key, url, undefined, overwrite, '.png');
          }
  
      },
  
      /**
      * Adds a Compressed Texture Image to the current load queue.
      *
      * Compressed Textures are a WebGL only feature, and require 3rd party tools to create.
      * Available tools include Texture Packer, PVRTexTool, DirectX Texture Tool and Mali Texture Compression Tool.
      *
      * Supported texture compression formats are: PVRTC, S3TC and ETC1.
      * Supported file formats are: PVR, DDS, KTX and PKM.
      * 
      * The formats that support all 3 compression algorithms are PVR and KTX.
      * PKM only supports ETC1, and DDS only S3TC for now.
      *
      * The texture path object looks like this:
      *
      * ```
      * load.texture('factory', {
      *     etc1: 'assets/factory_etc1.pkm',
      *     s3tc: 'assets/factory_dxt1.pvr',
      *     pvrtc: 'assets/factory_pvrtc.pvr',
      *     truecolor: 'assets/factory.png'
      * });
      * ```
      * 
      * The `truecolor` property points to a standard PNG file, that will be used if none of the 
      * compressed formats are supported by the browser / GPU.
      * 
      * The file is **not** loaded immediately after calling this method. The file is added to the queue ready to be loaded when the loader starts.
      *
      * The key must be a unique String. It is used to add the file to the Phaser.Cache upon successful load.
      *
      * Retrieve the image via `Cache.getImage(key)`
      *
      * The URL can be relative or absolute. If the URL is relative the `Loader.baseURL` and `Loader.path` values will be prepended to it.
      *
      * If the URL isn't specified the Loader will take the key and create a filename from that. For example if the key is "alien"
      * and no URL is given then the Loader will set the URL to be "alien.pvr". It will always add `.pvr` as the extension.
      * If you do not desire this action then provide a URL.
      *
      * @method Phaser.Loader#texture
      * @param {string} key - Unique asset key of this image file.
      * @param {object} object - The texture path data object.
      * @param {boolean} [overwrite=false] - If an unloaded file with a matching key already exists in the queue, this entry will overwrite it.
      * @return {Phaser.Loader} This Loader instance.
      */
      texture: function (key, object, overwrite) {
  
          if (this.game.renderType === Phaser.WEBGL)
          {
              var compression = this.game.renderer.extensions.compression;
              var exkey;
  
              for (exkey in object)
              {
                  if (exkey.toUpperCase() in compression)
                  {
                      return this.addToFileList('texture', key, object[exkey], undefined, overwrite, '.pvr');
                  }
              }
          }
  
          // Check if we have a truecolor texture to fallback.
          // Also catches calls to this function that are from a Canvas renderer
  
          if (object['truecolor'])
          {
              this.addToFileList('image', key, object['truecolor'], undefined, overwrite, '.png');
          }
  
          return this;
  
      },
  
      /**
      * Adds an array of images to the current load queue.
      *
      * It works by passing each element of the array to the Loader.image method.
      *
      * The files are **not** loaded immediately after calling this method. The files are added to the queue ready to be loaded when the loader starts.
      *
      * Phaser can load all common image types: png, jpg, gif and any other format the browser can natively handle.
      *
      * The keys must be unique Strings. They are used to add the files to the Phaser.Cache upon successful load.
      *
      * Retrieve the images via `Cache.getImage(key)`
      *
      * The URL can be relative or absolute. If the URL is relative the `Loader.baseURL` and `Loader.path` values will be prepended to it.
      *
      * If the URL isn't specified the Loader will take the key and create a filename from that. For example if the key is "alien"
      * and no URL is given then the Loader will set the URL to be "alien.png". It will always add `.png` as the extension.
      * If you do not desire this action then provide a URL.
      *
      * @method Phaser.Loader#images
      * @param {array} keys - An array of unique asset keys of the image files.
      * @param {array} [urls] - Optional array of URLs. If undefined or `null` the url will be set to `<key>.png`, i.e. if `key` was "alien" then the URL will be "alien.png". If provided the URLs array length must match the keys array length.
      * @return {Phaser.Loader} This Loader instance.
       */
      images: function (keys, urls) {
  
          if (Array.isArray(urls))
          {
              for (var i = 0; i < keys.length; i++)
              {
                  this.image(keys[i], urls[i]);
              }
          }
          else
          {
              for (var i = 0; i < keys.length; i++)
              {
                  this.image(keys[i]);
              }
          }
  
          return this;
  
      },
  
      /**
      * Adds a Text file to the current load queue.
      *
      * The file is **not** loaded immediately after calling this method. The file is added to the queue ready to be loaded when the loader starts.
      *
      * The key must be a unique String. It is used to add the file to the Phaser.Cache upon successful load.
      *
      * Retrieve the file via `Cache.getText(key)`
      *
      * The URL can be relative or absolute. If the URL is relative the `Loader.baseURL` and `Loader.path` values will be prepended to it.
      *
      * If the URL isn't specified the Loader will take the key and create a filename from that. For example if the key is "alien"
      * and no URL is given then the Loader will set the URL to be "alien.txt". It will always add `.txt` as the extension.
      * If you do not desire this action then provide a URL.
      *
      * @method Phaser.Loader#text
      * @param {string} key - Unique asset key of the text file.
      * @param {string} [url] - URL of the text file. If undefined or `null` the url will be set to `<key>.txt`, i.e. if `key` was "alien" then the URL will be "alien.txt".
      * @param {boolean} [overwrite=false] - If an unloaded file with a matching key already exists in the queue, this entry will overwrite it.
      * @return {Phaser.Loader} This Loader instance.
      */
      text: function (key, url, overwrite) {
  
          return this.addToFileList('text', key, url, undefined, overwrite, '.txt');
  
      },
  
      /**
      * Adds a JSON file to the current load queue.
      *
      * The file is **not** loaded immediately after calling this method. The file is added to the queue ready to be loaded when the loader starts.
      *
      * The key must be a unique String. It is used to add the file to the Phaser.Cache upon successful load.
      *
      * Retrieve the file via `Cache.getJSON(key)`. JSON files are automatically parsed upon load.
      * If you need to control when the JSON is parsed then use `Loader.text` instead and parse the text file as needed.
      *
      * The URL can be relative or absolute. If the URL is relative the `Loader.baseURL` and `Loader.path` values will be prepended to it.
      *
      * If the URL isn't specified the Loader will take the key and create a filename from that. For example if the key is "alien"
      * and no URL is given then the Loader will set the URL to be "alien.json". It will always add `.json` as the extension.
      * If you do not desire this action then provide a URL.
      *
      * @method Phaser.Loader#json
      * @param {string} key - Unique asset key of the json file.
      * @param {string} [url] - URL of the JSON file. If undefined or `null` the url will be set to `<key>.json`, i.e. if `key` was "alien" then the URL will be "alien.json".
      * @param {boolean} [overwrite=false] - If an unloaded file with a matching key already exists in the queue, this entry will overwrite it.
      * @return {Phaser.Loader} This Loader instance.
      */
      json: function (key, url, overwrite) {
  
          return this.addToFileList('json', key, url, undefined, overwrite, '.json');
  
      },
  
      /**
      * Adds a fragment shader file to the current load queue.
      *
      * The file is **not** loaded immediately after calling this method. The file is added to the queue ready to be loaded when the loader starts.
      *
      * The key must be a unique String. It is used to add the file to the Phaser.Cache upon successful load.
      *
      * Retrieve the file via `Cache.getShader(key)`.
      *
      * The URL can be relative or absolute. If the URL is relative the `Loader.baseURL` and `Loader.path` values will be prepended to it.
      *
      * If the URL isn't specified the Loader will take the key and create a filename from that. For example if the key is "blur"
      * and no URL is given then the Loader will set the URL to be "blur.frag". It will always add `.frag` as the extension.
      * If you do not desire this action then provide a URL.
      *
      * @method Phaser.Loader#shader
      * @param {string} key - Unique asset key of the fragment file.
      * @param {string} [url] - URL of the fragment file. If undefined or `null` the url will be set to `<key>.frag`, i.e. if `key` was "blur" then the URL will be "blur.frag".
      * @param {boolean} [overwrite=false] - If an unloaded file with a matching key already exists in the queue, this entry will overwrite it.
      * @return {Phaser.Loader} This Loader instance.
      */
      shader: function (key, url, overwrite) {
  
          return this.addToFileList('shader', key, url, undefined, overwrite, '.frag');
  
      },
  
      /**
      * Adds an XML file to the current load queue.
      *
      * The file is **not** loaded immediately after calling this method. The file is added to the queue ready to be loaded when the loader starts.
      *
      * The key must be a unique String. It is used to add the file to the Phaser.Cache upon successful load.
      *
      * Retrieve the file via `Cache.getXML(key)`.
      *
      * The URL can be relative or absolute. If the URL is relative the `Loader.baseURL` and `Loader.path` values will be prepended to it.
      *
      * If the URL isn't specified the Loader will take the key and create a filename from that. For example if the key is "alien"
      * and no URL is given then the Loader will set the URL to be "alien.xml". It will always add `.xml` as the extension.
      * If you do not desire this action then provide a URL.
      *
      * @method Phaser.Loader#xml
      * @param {string} key - Unique asset key of the xml file.
      * @param {string} [url] - URL of the XML file. If undefined or `null` the url will be set to `<key>.xml`, i.e. if `key` was "alien" then the URL will be "alien.xml".
      * @param {boolean} [overwrite=false] - If an unloaded file with a matching key already exists in the queue, this entry will overwrite it.
      * @return {Phaser.Loader} This Loader instance.
      */
      xml: function (key, url, overwrite) {
  
          return this.addToFileList('xml', key, url, undefined, overwrite, '.xml');
  
      },
  
      /**
      * Adds a JavaScript file to the current load queue.
      *
      * The file is **not** loaded immediately after calling this method. The file is added to the queue ready to be loaded when the loader starts.
      *
      * The key must be a unique String.
      *
      * The URL can be relative or absolute. If the URL is relative the `Loader.baseURL` and `Loader.path` values will be prepended to it.
      *
      * If the URL isn't specified the Loader will take the key and create a filename from that. For example if the key is "alien"
      * and no URL is given then the Loader will set the URL to be "alien.js". It will always add `.js` as the extension.
      * If you do not desire this action then provide a URL.
      *
      * Upon successful load the JavaScript is automatically turned into a script tag and executed, so be careful what you load!
      *
      * A callback, which will be invoked as the script tag has been created, can also be specified.
      * The callback must return relevant `data`.
      *
      * @method Phaser.Loader#script
      * @param {string} key - Unique asset key of the script file.
      * @param {string} [url] - URL of the JavaScript file. If undefined or `null` the url will be set to `<key>.js`, i.e. if `key` was "alien" then the URL will be "alien.js".
      * @param {function} [callback=(none)] - Optional callback that will be called after the script tag has loaded, so you can perform additional processing.
      * @param {object} [callbackContext=(loader)] - The context under which the callback will be applied. If not specified it will use the Phaser Loader as the context.
      * @return {Phaser.Loader} This Loader instance.
      */
      script: function (key, url, callback, callbackContext) {
  
          if (callback === undefined) { callback = false; }
  
          if (callback !== false && callbackContext === undefined) { callbackContext = this; }
  
          return this.addToFileList('script', key, url, { syncPoint: true, callback: callback, callbackContext: callbackContext }, false, '.js');
  
      },
  
      /**
      * Adds a binary file to the current load queue.
      *
      * The file is **not** loaded immediately after calling this method. The file is added to the queue ready to be loaded when the loader starts.
      *
      * The key must be a unique String. It is used to add the file to the Phaser.Cache upon successful load.
      *
      * Retrieve the file via `Cache.getBinary(key)`.
      *
      * The URL can be relative or absolute. If the URL is relative the `Loader.baseURL` and `Loader.path` values will be prepended to it.
      *
      * If the URL isn't specified the Loader will take the key and create a filename from that. For example if the key is "alien"
      * and no URL is given then the Loader will set the URL to be "alien.bin". It will always add `.bin` as the extension.
      * If you do not desire this action then provide a URL.
      *
      * It will be loaded via xhr with a responseType of "arraybuffer". You can specify an optional callback to process the file after load.
      * When the callback is called it will be passed 2 parameters: the key of the file and the file data.
      *
      * WARNING: If a callback is specified the data will be set to whatever it returns. Always return the data object, even if you didn't modify it.
      *
      * @method Phaser.Loader#binary
      * @param {string} key - Unique asset key of the binary file.
      * @param {string} [url] - URL of the binary file. If undefined or `null` the url will be set to `<key>.bin`, i.e. if `key` was "alien" then the URL will be "alien.bin".
      * @param {function} [callback=(none)] - Optional callback that will be passed the file after loading, so you can perform additional processing on it.
      * @param {object} [callbackContext] - The context under which the callback will be applied. If not specified it will use the callback itself as the context.
      * @return {Phaser.Loader} This Loader instance.
      */
      binary: function (key, url, callback, callbackContext) {
  
          if (callback === undefined) { callback = false; }
  
          // Why is the default callback context the ..callback?
          if (callback !== false && callbackContext === undefined) { callbackContext = callback; }
  
          return this.addToFileList('binary', key, url, { callback: callback, callbackContext: callbackContext }, false, '.bin');
  
      },
  
      /**
      * Adds a Sprite Sheet to the current load queue.
      *
      * The file is **not** loaded immediately after calling this method. The file is added to the queue ready to be loaded when the loader starts.
      *
      * To clarify the terminology that Phaser uses: A Sprite Sheet is an image containing frames, usually of an animation, that are all equal
      * dimensions and often in sequence. For example if the frame size is 32x32 then every frame in the sprite sheet will be that size.
      * Sometimes (outside of Phaser) the term "sprite sheet" is used to refer to a texture atlas.
      * A Texture Atlas works by packing together images as best it can, using whatever frame sizes it likes, often with cropping and trimming
      * the frames in the process. Software such as Texture Packer, Flash CC or Shoebox all generate texture atlases, not sprite sheets.
      * If you've got an atlas then use `Loader.atlas` instead.
      *
      * The key must be a unique String. It is used to add the image to the Phaser.Cache upon successful load.
      *
      * Retrieve the file via `Cache.getImage(key)`. Sprite sheets, being image based, live in the same Cache as all other Images.
      *
      * The URL can be relative or absolute. If the URL is relative the `Loader.baseURL` and `Loader.path` values will be prepended to it.
      *
      * If the URL isn't specified the Loader will take the key and create a filename from that. For example if the key is "alien"
      * and no URL is given then the Loader will set the URL to be "alien.png". It will always add `.png` as the extension.
      * If you do not desire this action then provide a URL.
      *
      * @method Phaser.Loader#spritesheet
      * @param {string} key - Unique asset key of the sheet file.
      * @param {string} url - URL of the sprite sheet file. If undefined or `null` the url will be set to `<key>.png`, i.e. if `key` was "alien" then the URL will be "alien.png".
      * @param {number} frameWidth - Width in pixels of a single frame in the sprite sheet.
      * @param {number} frameHeight - Height in pixels of a single frame in the sprite sheet.
      * @param {number} [frameMax=-1] - How many frames in this sprite sheet. If not specified it will divide the whole image into frames.
      * @param {number} [margin=0] - If the frames have been drawn with a margin, specify the amount here.
      * @param {number} [spacing=0] - If the frames have been drawn with spacing between them, specify the amount here.
      * @param {number} [skipFrames=0] - Skip a number of frames. Useful when there are multiple sprite sheets in one image.
      * @return {Phaser.Loader} This Loader instance.
      */
      spritesheet: function (key, url, frameWidth, frameHeight, frameMax, margin, spacing, skipFrames) {
  
          if (frameMax === undefined) { frameMax = -1; }
          if (margin === undefined) { margin = 0; }
          if (spacing === undefined) { spacing = 0; }
          if (skipFrames === undefined) { skipFrames = 0; }
  
          return this.addToFileList('spritesheet', key, url, { frameWidth: frameWidth, frameHeight: frameHeight, frameMax: frameMax, margin: margin, spacing: spacing, skipFrames: skipFrames }, false, '.png');
  
      },
  
      /**
      * Adds an audio file to the current load queue.
      *
      * The file is **not** loaded immediately after calling this method. The file is added to the queue ready to be loaded when the loader starts.
      *
      * The key must be a unique String. It is used to add the file to the Phaser.Cache upon successful load.
      *
      * Retrieve the file via `Cache.getSound(key)`.
      *
      * The URL can be relative or absolute. If the URL is relative the `Loader.baseURL` and `Loader.path` values will be prepended to it.
      *
      * Mobile warning: There are some mobile devices (certain iPad 2 and iPad Mini revisions) that cannot play 48000 Hz audio.
      * When they try to play the audio becomes extremely distorted and buzzes, eventually crashing the sound system.
      * The solution is to use a lower encoding rate such as 44100 Hz.
      *
      * @method Phaser.Loader#audio
      * @param {string} key - Unique asset key of the audio file.
      * @param {string|string[]|object[]} urls - Either a single string or an array of URIs or pairs of `{uri: .., type: ..}`.
      *    If an array is specified then the first URI (or URI + mime pair) that is device-compatible will be selected.
      *    For example: `"jump.mp3"`, `['jump.mp3', 'jump.ogg', 'jump.m4a']`, or `[{uri: "data:<opus_resource>", type: 'opus'}, 'fallback.mp3']`.
      *    BLOB and DATA URIs can be used but only support automatic detection when used in the pair form; otherwise the format must be manually checked before adding the resource.
      * @param {boolean} [autoDecode=true] - When using Web Audio the audio files can either be decoded at load time or run-time.
      *    Audio files can't be played until they are decoded and, if specified, this enables immediate decoding. Decoding is a non-blocking async process, however it consumes huge amounts of CPU time on mobiles especially.
      * @return {Phaser.Loader} This Loader instance.
      */
      audio: function (key, urls, autoDecode) {
  
          if (this.game.sound.noAudio)
          {
              return this;
          }
  
          if (autoDecode === undefined) { autoDecode = true; }
  
          if (typeof urls === 'string')
          {
              urls = [urls];
          }
  
          return this.addToFileList('audio', key, urls, { buffer: null, autoDecode: autoDecode });
  
      },
  
      /**
      * Adds an audio sprite file to the current load queue.
      *
      * The file is **not** loaded immediately after calling this method. The file is added to the queue ready to be loaded when the loader starts.
      *
      * The key must be a unique String. It is used to add the file to the Phaser.Cache upon successful load.
      *
      * Audio Sprites are a combination of audio files and a JSON configuration.
      *
      * The JSON follows the format of that created by https://github.com/tonistiigi/audiosprite
      *
      * Retrieve the file via `Cache.getSoundData(key)`.
      *
      * The URL can be relative or absolute. If the URL is relative the `Loader.baseURL` and `Loader.path` values will be prepended to it.
      *
      * @method Phaser.Loader#audioSprite
      * @param {string} key - Unique asset key of the audio file.
      * @param {Array|string} urls - An array containing the URLs of the audio files, i.e.: [ 'audiosprite.mp3', 'audiosprite.ogg', 'audiosprite.m4a' ] or a single string containing just one URL.
      * @param {string} [jsonURL=null] - The URL of the audiosprite configuration JSON object. If you wish to pass the data directly set this parameter to null.
      * @param {string|object} [jsonData=null] - A JSON object or string containing the audiosprite configuration data. This is ignored if jsonURL is not null.
      * @param {boolean} [autoDecode=true] - When using Web Audio the audio files can either be decoded at load time or run-time.
      *    Audio files can't be played until they are decoded and, if specified, this enables immediate decoding. Decoding is a non-blocking async process, however it consumes huge amounts of CPU time on mobiles especially.
      * @return {Phaser.Loader} This Loader instance.
      */
      audioSprite: function (key, urls, jsonURL, jsonData, autoDecode) {
  
          if (this.game.sound.noAudio)
          {
              return this;
          }
  
          if (jsonURL === undefined) { jsonURL = null; }
          if (jsonData === undefined) { jsonData = null; }
          if (autoDecode === undefined) { autoDecode = true; }
  
          this.audio(key, urls, autoDecode);
  
          if (jsonURL)
          {
              this.json(key + '-audioatlas', jsonURL);
          }
          else if (jsonData)
          {
              if (typeof jsonData === 'string')
              {
                  jsonData = JSON.parse(jsonData);
              }
  
              this.cache.addJSON(key + '-audioatlas', '', jsonData);
          }
          else
          {
              console.warn('Phaser.Loader.audiosprite - You must specify either a jsonURL or provide a jsonData object');
          }
  
          return this;
  
      },
  
      /**
      * A legacy alias for Loader.audioSprite. Please see that method for documentation.
      *
      * @method Phaser.Loader#audiosprite
      * @param {string} key - Unique asset key of the audio file.
      * @param {Array|string} urls - An array containing the URLs of the audio files, i.e.: [ 'audiosprite.mp3', 'audiosprite.ogg', 'audiosprite.m4a' ] or a single string containing just one URL.
      * @param {string} [jsonURL=null] - The URL of the audiosprite configuration JSON object. If you wish to pass the data directly set this parameter to null.
      * @param {string|object} [jsonData=null] - A JSON object or string containing the audiosprite configuration data. This is ignored if jsonURL is not null.
      * @param {boolean} [autoDecode=true] - When using Web Audio the audio files can either be decoded at load time or run-time.
      *    Audio files can't be played until they are decoded and, if specified, this enables immediate decoding. Decoding is a non-blocking async process, however it consumes huge amounts of CPU time on mobiles especially.
      * @return {Phaser.Loader} This Loader instance.
      */
      audiosprite: function (key, urls, jsonURL, jsonData, autoDecode) {
  
          return this.audioSprite(key, urls, jsonURL, jsonData, autoDecode);
  
      },
  
      /**
      * Adds a video file to the current load queue.
      *
      * The file is **not** loaded immediately after calling this method. The file is added to the queue ready to be loaded when the loader starts.
      *
      * The key must be a unique String. It is used to add the file to the Phaser.Cache upon successful load.
      *
      * Retrieve the file via `Cache.getVideo(key)`.
      *
      * The URL can be relative or absolute. If the URL is relative the `Loader.baseURL` and `Loader.path` values will be prepended to it.
      *
      * You don't need to preload a video in order to play it in your game. See `Video.createVideoFromURL` for details.
      *
      * @method Phaser.Loader#video
      * @param {string} key - Unique asset key of the video file.
      * @param {string|string[]|object[]} urls - Either a single string or an array of URIs or pairs of `{uri: .., type: ..}`.
      *    If an array is specified then the first URI (or URI + mime pair) that is device-compatible will be selected.
      *    For example: `"boom.mp4"`, `['boom.mp4', 'boom.ogg', 'boom.webm']`, or `[{uri: "data:<opus_resource>", type: 'opus'}, 'fallback.mp4']`.
      *    BLOB and DATA URIs can be used but only support automatic detection when used in the pair form; otherwise the format must be manually checked before adding the resource.
      * @param {string} [loadEvent='canplaythrough'] - This sets the Video source event to listen for before the load is considered complete.
      *    'canplaythrough' implies the video has downloaded enough, and bandwidth is high enough that it can be played to completion.
      *    'canplay' implies the video has downloaded enough to start playing, but not necessarily to finish.
      *    'loadeddata' just makes sure that the video meta data and first frame have downloaded. Phaser uses this value automatically if the
      *    browser is detected as being Firefox and no `loadEvent` is given, otherwise it defaults to `canplaythrough`.
      * @param {boolean} [asBlob=false] - Video files can either be loaded via the creation of a video element which has its src property set.
      *    Or they can be loaded via xhr, stored as binary data in memory and then converted to a Blob. This isn't supported in IE9 or Android 2.
      *    If you need to have the same video playing at different times across multiple Sprites then you need to load it as a Blob.
      * @return {Phaser.Loader} This Loader instance.
      */
      video: function (key, urls, loadEvent, asBlob) {
  
          if (loadEvent === undefined)
          {
              if (this.game.device.firefox)
              {
                  loadEvent = 'loadeddata';
              }
              else
              {
                  loadEvent = 'canplaythrough';
              }
          }
  
          if (asBlob === undefined) { asBlob = false; }
  
          if (typeof urls === 'string')
          {
              urls = [urls];
          }
  
          return this.addToFileList('video', key, urls, { buffer: null, asBlob: asBlob, loadEvent: loadEvent });
  
      },
  
      /**
      * Adds a Tile Map data file to the current load queue.
      *
      * Phaser can load data in two different formats: CSV and Tiled JSON.
      * 
      * Tiled is a free software package, specifically for creating tilemaps, and is available from http://www.mapeditor.org
      *
      * You can choose to either load the data externally, by providing a URL to a json file.
      * Or you can pass in a JSON object or String via the `data` parameter.
      * If you pass a String the data is automatically run through `JSON.parse` and then immediately added to the Phaser.Cache.
      *
      * If a URL is provided the file is **not** loaded immediately after calling this method, but is added to the load queue.
      *
      * The key must be a unique String. It is used to add the file to the Phaser.Cache upon successful load.
      *
      * Retrieve the file via `Cache.getTilemapData(key)`. JSON files are automatically parsed upon load.
      * If you need to control when the JSON is parsed then use `Loader.text` instead and parse the text file as needed.
      *
      * The URL can be relative or absolute. If the URL is relative the `Loader.baseURL` and `Loader.path` values will be prepended to it.
      *
      * If the URL isn't specified and no data is given then the Loader will take the key and create a filename from that.
      * For example if the key is "level1" and no URL or data is given then the Loader will set the URL to be "level1.json".
      * If you set the format to be Tilemap.CSV it will set the URL to be "level1.csv" instead.
      *
      * If you do not desire this action then provide a URL or data object.
      *
      * @method Phaser.Loader#tilemap
      * @param {string} key - Unique asset key of the tilemap data.
      * @param {string} [url] - URL of the tile map file. If undefined or `null` and no data is given the url will be set to `<key>.json`, i.e. if `key` was "level1" then the URL will be "level1.json".
      * @param {object|string} [data] - An optional JSON data object. If given then the url is ignored and this JSON object is used for map data instead.
      * @param {number} [format=Phaser.Tilemap.CSV] - The format of the map data. Either Phaser.Tilemap.CSV or Phaser.Tilemap.TILED_JSON.
      * @return {Phaser.Loader} This Loader instance.
      */
      tilemap: function (key, url, data, format) {
  
          if (url === undefined) { url = null; }
          if (data === undefined) { data = null; }
          if (format === undefined) { format = Phaser.Tilemap.CSV; }
  
          if (!url && !data)
          {
              if (format === Phaser.Tilemap.CSV)
              {
                  url = key + '.csv';
              }
              else
              {
                  url = key + '.json';
              }
          }
  
          //  A map data object has been given
          if (data)
          {
              switch (format)
              {
                  //  A csv string or object has been given
                  case Phaser.Tilemap.CSV:
                      break;
  
                  //  A json string or object has been given
                  case Phaser.Tilemap.TILED_JSON:
  
                      if (typeof data === 'string')
                      {
                          data = JSON.parse(data);
                      }
                      break;
              }
  
              this.cache.addTilemap(key, null, data, format);
          }
          else
          {
              this.addToFileList('tilemap', key, url, { format: format });
          }
  
          return this;
  
      },
  
      /**
      * Adds a physics data file to the current load queue.
      *
      * The data must be in `Lime + Corona` JSON format. [Physics Editor](https://www.codeandweb.com) by code'n'web exports in this format natively.
      *
      * You can choose to either load the data externally, by providing a URL to a json file.
      * Or you can pass in a JSON object or String via the `data` parameter.
      * If you pass a String the data is automatically run through `JSON.parse` and then immediately added to the Phaser.Cache.
      *
      * If a URL is provided the file is **not** loaded immediately after calling this method, but is added to the load queue.
      *
      * The key must be a unique String. It is used to add the file to the Phaser.Cache upon successful load.
      *
      * Retrieve the file via `Cache.getJSON(key)`. JSON files are automatically parsed upon load.
      * If you need to control when the JSON is parsed then use `Loader.text` instead and parse the text file as needed.
      *
      * The URL can be relative or absolute. If the URL is relative the `Loader.baseURL` and `Loader.path` values will be prepended to it.
      *
      * If the URL isn't specified and no data is given then the Loader will take the key and create a filename from that.
      * For example if the key is "alien" and no URL or data is given then the Loader will set the URL to be "alien.json".
      * It will always use `.json` as the extension.
      *
      * If you do not desire this action then provide a URL or data object.
      *
      * @method Phaser.Loader#physics
      * @param {string} key - Unique asset key of the physics json data.
      * @param {string} [url] - URL of the physics data file. If undefined or `null` and no data is given the url will be set to `<key>.json`, i.e. if `key` was "alien" then the URL will be "alien.json".
      * @param {object|string} [data] - An optional JSON data object. If given then the url is ignored and this JSON object is used for physics data instead.
      * @param {string} [format=Phaser.Physics.LIME_CORONA_JSON] - The format of the physics data.
      * @return {Phaser.Loader} This Loader instance.
      */
      physics: function (key, url, data, format) {
  
          if (url === undefined) { url = null; }
          if (data === undefined) { data = null; }
          if (format === undefined) { format = Phaser.Physics.LIME_CORONA_JSON; }
  
          if (!url && !data)
          {
              url = key + '.json';
          }
  
          //  A map data object has been given
          if (data)
          {
              if (typeof data === 'string')
              {
                  data = JSON.parse(data);
              }
  
              this.cache.addPhysicsData(key, null, data, format);
          }
          else
          {
              this.addToFileList('physics', key, url, { format: format });
          }
  
          return this;
  
      },
  
      /**
      * Adds Bitmap Font files to the current load queue.
      *
      * To create the Bitmap Font files you can use:
      *
      * BMFont (Windows, free): http://www.angelcode.com/products/bmfont/
      * Glyph Designer (OS X, commercial): http://www.71squared.com/en/glyphdesigner
      * Littera (Web-based, free): http://kvazars.com/littera/
      *
      * You can choose to either load the data externally, by providing a URL to an xml file.
      * Or you can pass in an XML object or String via the `xmlData` parameter.
      * If you pass a String the data is automatically run through `Loader.parseXML` and then immediately added to the Phaser.Cache.
      *
      * If URLs are provided the files are **not** loaded immediately after calling this method, but are added to the load queue.
      *
      * The key must be a unique String. It is used to add the file to the Phaser.Cache upon successful load.
      *
      * Retrieve the file via `Cache.getBitmapFont(key)`. XML files are automatically parsed upon load.
      * If you need to control when the XML is parsed then use `Loader.text` instead and parse the XML file as needed.
      *
      * The URLs can be relative or absolute. If the URL is relative the `Loader.baseURL` and `Loader.path` values will be prepended to it.
      *
      * If the textureURL isn't specified then the Loader will take the key and create a filename from that.
      * For example if the key is "megaFont" and textureURL is null then the Loader will set the URL to be "megaFont.png".
      * The same is true for the atlasURL. If atlasURL isn't specified and no atlasData has been provided then the Loader will
      * set the atlasURL to be the key. For example if the key is "megaFont" the atlasURL will be set to "megaFont.xml".
      *
      * If you do not desire this action then provide URLs and / or a data object.
      *
      * @method Phaser.Loader#bitmapFont
      * @param {string} key - Unique asset key of the bitmap font.
      * @param {string} textureURL -  URL of the Bitmap Font texture file. If undefined or `null` the url will be set to `<key>.png`, i.e. if `key` was "megaFont" then the URL will be "megaFont.png".
      * @param {string} atlasURL - URL of the Bitmap Font atlas file (xml/json). If undefined or `null` AND `atlasData` is null, the url will be set to `<key>.xml`, i.e. if `key` was "megaFont" then the URL will be "megaFont.xml".
      * @param {object} atlasData - An optional Bitmap Font atlas in string form (stringified xml/json).
      * @param {number} [xSpacing=0] - If you'd like to add additional horizontal spacing between the characters then set the pixel value here.
      * @param {number} [ySpacing=0] - If you'd like to add additional vertical spacing between the lines then set the pixel value here.
      * @return {Phaser.Loader} This Loader instance.
      */
      bitmapFont: function (key, textureURL, atlasURL, atlasData, xSpacing, ySpacing) {
  
          if (textureURL === undefined || textureURL === null)
          {
              textureURL = key + '.png';
          }
  
          if (atlasURL === undefined) { atlasURL = null; }
          if (atlasData === undefined) { atlasData = null; }
  
          if (atlasURL === null && atlasData === null)
          {
              atlasURL = key + '.xml';
          }
  
          if (xSpacing === undefined) { xSpacing = 0; }
          if (ySpacing === undefined) { ySpacing = 0; }
  
          //  A URL to a json/xml atlas has been given
          if (atlasURL)
          {
              this.addToFileList('bitmapfont', key, textureURL, { atlasURL: atlasURL, xSpacing: xSpacing, ySpacing: ySpacing });
          }
          else
          {
              //  A stringified xml/json atlas has been given
              if (typeof atlasData === 'string')
              {
                  var json, xml;
  
                  try
                  {
                      json = JSON.parse(atlasData);
                  }
                  catch ( e )
                  {
                      xml = this.parseXml(atlasData);
                  }
  
                  if (!xml && !json)
                  {
                      throw new Error("Phaser.Loader. Invalid Bitmap Font atlas given");
                  }
  
                  this.addToFileList('bitmapfont', key, textureURL, { atlasURL: null, atlasData: json || xml,
                      atlasType: (!!json ? 'json' : 'xml'), xSpacing: xSpacing, ySpacing: ySpacing });
              }
          }
  
          return this;
  
      },
  
      /**
      * Adds a Texture Atlas file to the current load queue.
      *
      * Unlike `Loader.atlasJSONHash` this call expects the atlas data to be in a JSON Array format.
      *
      * To create the Texture Atlas you can use tools such as:
      *
      * [Texture Packer](https://www.codeandweb.com/texturepacker/phaser)
      * [Shoebox](http://renderhjs.net/shoebox/)
      *
      * If using Texture Packer we recommend you enable "Trim sprite names".
      * If your atlas software has an option to "rotate" the resulting frames, you must disable it.
      *
      * You can choose to either load the data externally, by providing a URL to a json file.
      * Or you can pass in a JSON object or String via the `atlasData` parameter.
      * If you pass a String the data is automatically run through `JSON.parse` and then immediately added to the Phaser.Cache.
      *
      * If URLs are provided the files are **not** loaded immediately after calling this method, but are added to the load queue.
      *
      * The key must be a unique String. It is used to add the file to the Phaser.Cache upon successful load.
      *
      * Retrieve the file via `Cache.getImage(key)`. JSON files are automatically parsed upon load.
      * If you need to control when the JSON is parsed then use `Loader.text` instead and parse the JSON file as needed.
      *
      * The URLs can be relative or absolute. If the URL is relative the `Loader.baseURL` and `Loader.path` values will be prepended to it.
      *
      * If the textureURL isn't specified then the Loader will take the key and create a filename from that.
      * For example if the key is "player" and textureURL is null then the Loader will set the URL to be "player.png".
      * The same is true for the atlasURL. If atlasURL isn't specified and no atlasData has been provided then the Loader will
      * set the atlasURL to be the key. For example if the key is "player" the atlasURL will be set to "player.json".
      *
      * If you do not desire this action then provide URLs and / or a data object.
      *
      * @method Phaser.Loader#atlasJSONArray
      * @param {string} key - Unique asset key of the texture atlas file.
      * @param {string} [textureURL] - URL of the texture atlas image file. If undefined or `null` the url will be set to `<key>.png`, i.e. if `key` was "alien" then the URL will be "alien.png".
      * @param {string} [atlasURL] - URL of the texture atlas data file. If undefined or `null` and no atlasData is given, the url will be set to `<key>.json`, i.e. if `key` was "alien" then the URL will be "alien.json".
      * @param {object} [atlasData] - A JSON data object. You don't need this if the data is being loaded from a URL.
      * @return {Phaser.Loader} This Loader instance.
      */
      atlasJSONArray: function (key, textureURL, atlasURL, atlasData) {
  
          return this.atlas(key, textureURL, atlasURL, atlasData, Phaser.Loader.TEXTURE_ATLAS_JSON_ARRAY);
  
      },
  
      /**
      * Adds a Texture Atlas file to the current load queue.
      *
      * Unlike `Loader.atlas` this call expects the atlas data to be in a JSON Hash format.
      *
      * To create the Texture Atlas you can use tools such as:
      *
      * [Texture Packer](https://www.codeandweb.com/texturepacker/phaser)
      * [Shoebox](http://renderhjs.net/shoebox/)
      *
      * If using Texture Packer we recommend you enable "Trim sprite names".
      * If your atlas software has an option to "rotate" the resulting frames, you must disable it.
      *
      * You can choose to either load the data externally, by providing a URL to a json file.
      * Or you can pass in a JSON object or String via the `atlasData` parameter.
      * If you pass a String the data is automatically run through `JSON.parse` and then immediately added to the Phaser.Cache.
      *
      * If URLs are provided the files are **not** loaded immediately after calling this method, but are added to the load queue.
      *
      * The key must be a unique String. It is used to add the file to the Phaser.Cache upon successful load.
      *
      * Retrieve the file via `Cache.getImage(key)`. JSON files are automatically parsed upon load.
      * If you need to control when the JSON is parsed then use `Loader.text` instead and parse the JSON file as needed.
      *
      * The URLs can be relative or absolute. If the URL is relative the `Loader.baseURL` and `Loader.path` values will be prepended to it.
      *
      * If the textureURL isn't specified then the Loader will take the key and create a filename from that.
      * For example if the key is "player" and textureURL is null then the Loader will set the URL to be "player.png".
      * The same is true for the atlasURL. If atlasURL isn't specified and no atlasData has been provided then the Loader will
      * set the atlasURL to be the key. For example if the key is "player" the atlasURL will be set to "player.json".
      *
      * If you do not desire this action then provide URLs and / or a data object.
      *
      * @method Phaser.Loader#atlasJSONHash
      * @param {string} key - Unique asset key of the texture atlas file.
      * @param {string} [textureURL] - URL of the texture atlas image file. If undefined or `null` the url will be set to `<key>.png`, i.e. if `key` was "alien" then the URL will be "alien.png".
      * @param {string} [atlasURL] - URL of the texture atlas data file. If undefined or `null` and no atlasData is given, the url will be set to `<key>.json`, i.e. if `key` was "alien" then the URL will be "alien.json".
      * @param {object} [atlasData] - A JSON data object. You don't need this if the data is being loaded from a URL.
      * @return {Phaser.Loader} This Loader instance.
      */
      atlasJSONHash: function (key, textureURL, atlasURL, atlasData) {
  
          return this.atlas(key, textureURL, atlasURL, atlasData, Phaser.Loader.TEXTURE_ATLAS_JSON_HASH);
  
      },
  
      /**
      * Adds a Texture Atlas file to the current load queue.
      *
      * This call expects the atlas data to be in the Starling XML data format.
      *
      * To create the Texture Atlas you can use tools such as:
      *
      * [Texture Packer](https://www.codeandweb.com/texturepacker/phaser)
      * [Shoebox](http://renderhjs.net/shoebox/)
      *
      * If using Texture Packer we recommend you enable "Trim sprite names".
      * If your atlas software has an option to "rotate" the resulting frames, you must disable it.
      *
      * You can choose to either load the data externally, by providing a URL to an xml file.
      * Or you can pass in an XML object or String via the `atlasData` parameter.
      * If you pass a String the data is automatically run through `Loader.parseXML` and then immediately added to the Phaser.Cache.
      *
      * If URLs are provided the files are **not** loaded immediately after calling this method, but are added to the load queue.
      *
      * The key must be a unique String. It is used to add the file to the Phaser.Cache upon successful load.
      *
      * Retrieve the file via `Cache.getImage(key)`. XML files are automatically parsed upon load.
      * If you need to control when the XML is parsed then use `Loader.text` instead and parse the XML file as needed.
      *
      * The URLs can be relative or absolute. If the URL is relative the `Loader.baseURL` and `Loader.path` values will be prepended to it.
      *
      * If the textureURL isn't specified then the Loader will take the key and create a filename from that.
      * For example if the key is "player" and textureURL is null then the Loader will set the URL to be "player.png".
      * The same is true for the atlasURL. If atlasURL isn't specified and no atlasData has been provided then the Loader will
      * set the atlasURL to be the key. For example if the key is "player" the atlasURL will be set to "player.xml".
      *
      * If you do not desire this action then provide URLs and / or a data object.
      *
      * @method Phaser.Loader#atlasXML
      * @param {string} key - Unique asset key of the texture atlas file.
      * @param {string} [textureURL] - URL of the texture atlas image file. If undefined or `null` the url will be set to `<key>.png`, i.e. if `key` was "alien" then the URL will be "alien.png".
      * @param {string} [atlasURL] - URL of the texture atlas data file. If undefined or `null` and no atlasData is given, the url will be set to `<key>.json`, i.e. if `key` was "alien" then the URL will be "alien.xml".
      * @param {object} [atlasData] - An XML data object. You don't need this if the data is being loaded from a URL.
      * @return {Phaser.Loader} This Loader instance.
      */
      atlasXML: function (key, textureURL, atlasURL, atlasData) {
  
          if (atlasURL === undefined) { atlasURL = null; }
          if (atlasData === undefined) { atlasData = null; }
  
          if (!atlasURL && !atlasData)
          {
              atlasURL = key + '.xml';
          }
  
          return this.atlas(key, textureURL, atlasURL, atlasData, Phaser.Loader.TEXTURE_ATLAS_XML_STARLING);
  
      },
  
      /**
      * Adds a Texture Atlas file to the current load queue.
      *
      * To create the Texture Atlas you can use tools such as:
      *
      * [Texture Packer](https://www.codeandweb.com/texturepacker/phaser)
      * [Shoebox](http://renderhjs.net/shoebox/)
      *
      * If using Texture Packer we recommend you enable "Trim sprite names".
      * If your atlas software has an option to "rotate" the resulting frames, you must disable it.
      *
      * You can choose to either load the data externally, by providing a URL to a json file.
      * Or you can pass in a JSON object or String via the `atlasData` parameter.
      * If you pass a String the data is automatically run through `JSON.parse` and then immediately added to the Phaser.Cache.
      *
      * If URLs are provided the files are **not** loaded immediately after calling this method, but are added to the load queue.
      *
      * The key must be a unique String. It is used to add the file to the Phaser.Cache upon successful load.
      *
      * Retrieve the file via `Cache.getImage(key)`. JSON files are automatically parsed upon load.
      * If you need to control when the JSON is parsed then use `Loader.text` instead and parse the JSON file as needed.
      *
      * The URLs can be relative or absolute. If the URL is relative the `Loader.baseURL` and `Loader.path` values will be prepended to it.
      *
      * If the textureURL isn't specified then the Loader will take the key and create a filename from that.
      * For example if the key is "player" and textureURL is null then the Loader will set the URL to be "player.png".
      * The same is true for the atlasURL. If atlasURL isn't specified and no atlasData has been provided then the Loader will
      * set the atlasURL to be the key. For example if the key is "player" the atlasURL will be set to "player.json".
      *
      * If you do not desire this action then provide URLs and / or a data object.
      *
      * @method Phaser.Loader#atlas
      * @param {string} key - Unique asset key of the texture atlas file.
      * @param {string} [textureURL] - URL of the texture atlas image file. If undefined or `null` the url will be set to `<key>.png`, i.e. if `key` was "alien" then the URL will be "alien.png".
      * @param {string} [atlasURL] - URL of the texture atlas data file. If undefined or `null` and no atlasData is given, the url will be set to `<key>.json`, i.e. if `key` was "alien" then the URL will be "alien.json".
      * @param {object} [atlasData] - A JSON or XML data object. You don't need this if the data is being loaded from a URL.
      * @param {number} [format] - The format of the data. Can be Phaser.Loader.TEXTURE_ATLAS_JSON_ARRAY (the default), Phaser.Loader.TEXTURE_ATLAS_JSON_HASH or Phaser.Loader.TEXTURE_ATLAS_XML_STARLING.
      * @return {Phaser.Loader} This Loader instance.
      */
      atlas: function (key, textureURL, atlasURL, atlasData, format) {
  
          if (textureURL === undefined || textureURL === null)
          {
              textureURL = key + '.png';
          }
  
          if (atlasURL === undefined) { atlasURL = null; }
          if (atlasData === undefined) { atlasData = null; }
          if (format === undefined) { format = Phaser.Loader.TEXTURE_ATLAS_JSON_ARRAY; }
  
          if (!atlasURL && !atlasData)
          {
              if (format === Phaser.Loader.TEXTURE_ATLAS_XML_STARLING)
              {
                  atlasURL = key + '.xml';
              }
              else
              {
                  atlasURL = key + '.json';
              }
          }
  
          //  A URL to a json/xml file has been given
          if (atlasURL)
          {
              this.addToFileList('textureatlas', key, textureURL, { atlasURL: atlasURL, format: format });
          }
          else
          {
              switch (format)
              {
                  //  A json string or object has been given
                  case Phaser.Loader.TEXTURE_ATLAS_JSON_ARRAY:
  
                      if (typeof atlasData === 'string')
                      {
                          atlasData = JSON.parse(atlasData);
                      }
                      break;
  
                  //  An xml string or object has been given
                  case Phaser.Loader.TEXTURE_ATLAS_XML_STARLING:
  
                      if (typeof atlasData === 'string')
                      {
                          var xml = this.parseXml(atlasData);
  
                          if (!xml)
                          {
                              throw new Error("Phaser.Loader. Invalid Texture Atlas XML given");
                          }
  
                          atlasData = xml;
                      }
                      break;
              }
  
              this.addToFileList('textureatlas', key, textureURL, { atlasURL: null, atlasData: atlasData, format: format });
  
          }
  
          return this;
  
      },
  
      /**
      * Add a synchronization point to the assets / files added within the supplied callback.
      *
      * A synchronization point denotes that an asset _must_ be completely loaded before
      * subsequent assets can be loaded. An asset marked as a sync-point does not need to wait
      * for previous assets to load (unless they are sync-points). Resources, such as packs, may still
      * be downloaded around sync-points, as long as they do not finalize loading.
      *
      * @method Phaser.Loader#withSyncPoint
      * @param {function} callback - The callback is invoked and is supplied with a single argument: the loader.
      * @param {object} [callbackContext=(loader)] - Context for the callback.
      * @return {Phaser.Loader} This Loader instance.
      */
      withSyncPoint: function (callback, callbackContext) {
  
          this._withSyncPointDepth++;
  
          try {
              callback.call(callbackContext || this, this);
          } finally {
              this._withSyncPointDepth--;
          }
  
          return this;
      },
  
      /**
      * Add a synchronization point to a specific file/asset in the load queue.
      *
      * This has no effect on already loaded assets.
      *
      * @method Phaser.Loader#addSyncPoint
      * @param {string} type - The type of resource to turn into a sync point (image, audio, xml, etc).
      * @param {string} key - Key of the file you want to turn into a sync point.
      * @return {Phaser.Loader} This Loader instance.
      * @see {@link Phaser.Loader#withSyncPoint withSyncPoint}
      */
      addSyncPoint: function (type, key) {
  
          var asset = this.getAsset(type, key);
  
          if (asset)
          {
              asset.file.syncPoint = true;
          }
  
          return this;
      },
  
      /**
      * Remove a file/asset from the loading queue.
      *
      * A file that is loaded or has started loading cannot be removed.
      *
      * @method Phaser.Loader#removeFile
      * @protected
      * @param {string} type - The type of resource to add to the list (image, audio, xml, etc).
      * @param {string} key - Key of the file you want to remove.
      */
      removeFile: function (type, key) {
  
          var asset = this.getAsset(type, key);
  
          if (asset)
          {
              if (!asset.loaded && !asset.loading)
              {
                  this._fileList.splice(asset.index, 1);
              }
          }
  
      },
  
      /**
      * Remove all file loading requests - this is _insufficient_ to stop current loading. Use `reset` instead.
      *
      * @method Phaser.Loader#removeAll
      * @protected
      */
      removeAll: function () {
  
          this._fileList.length = 0;
          this._flightQueue.length = 0;
  
      },
  
      /**
      * Start loading the assets. Normally you don't need to call this yourself as the StateManager will do so.
      *
      * @method Phaser.Loader#start
      */
      start: function () {
  
          if (this.isLoading)
          {
              return;
          }
  
          this.hasLoaded = false;
          this.isLoading = true;
  
          this.updateProgress();
  
          this.processLoadQueue();
  
      },
  
      /**
      * Process the next item(s) in the file/asset queue.
      *
      * Process the queue and start loading enough items to fill up the inflight queue.
      *
      * If a sync-file is encountered then subsequent asset processing is delayed until it completes.
      * The exception to this rule is that packfiles can be downloaded (but not processed) even if
      * there appear other sync files (ie. packs) - this enables multiple packfiles to be fetched in parallel.
      * such as during the start phaser.
      *
      * @method Phaser.Loader#processLoadQueue
      * @private
      */
      processLoadQueue: function () {
  
          if (!this.isLoading)
          {
              console.warn('Phaser.Loader - active loading canceled / reset');
              this.finishedLoading(true);
              return;
          }
  
          // Empty the flight queue as applicable
          for (var i = 0; i < this._flightQueue.length; i++)
          {
              var file = this._flightQueue[i];
  
              if (file.loaded || file.error)
              {
                  this._flightQueue.splice(i, 1);
                  i--;
  
                  file.loading = false;
                  file.requestUrl = null;
                  file.requestObject = null;
  
                  if (file.error)
                  {
                      this.onFileError.dispatch(file.key, file);
                  }
  
                  if (file.type !== 'packfile')
                  {
                      this._loadedFileCount++;
                      this.onFileComplete.dispatch(this.progress, file.key, !file.error, this._loadedFileCount, this._totalFileCount);
                  }
                  else if (file.type === 'packfile' && file.error)
                  {
                      // Non-error pack files are handled when processing the file queue
                      this._loadedPackCount++;
                      this.onPackComplete.dispatch(file.key, !file.error, this._loadedPackCount, this._totalPackCount);
                  }
  
              }
          }
  
          // When true further non-pack file downloads are suppressed
          var syncblock = false;
  
          var inflightLimit = this.enableParallel ? Phaser.Math.clamp(this.maxParallelDownloads, 1, 12) : 1;
  
          for (var i = this._processingHead; i < this._fileList.length; i++)
          {
              var file = this._fileList[i];
  
              // Pack is fetched (ie. has data) and is currently at the start of the process queue.
              if (file.type === 'packfile' && !file.error && file.loaded && i === this._processingHead)
              {
                  // Processing the pack / adds more files
                  this.processPack(file);
  
                  this._loadedPackCount++;
                  this.onPackComplete.dispatch(file.key, !file.error, this._loadedPackCount, this._totalPackCount);
              }
  
              if (file.loaded || file.error)
              {
                  // Item at the start of file list finished, can skip it in future
                  if (i === this._processingHead)
                  {
                      this._processingHead = i + 1;
                  }
              }
              else if (!file.loading && this._flightQueue.length < inflightLimit)
              {
                  // -> not loaded/failed, not loading
                  if (file.type === 'packfile' && !file.data)
                  {
                      // Fetches the pack data: the pack is processed above as it reaches queue-start.
                      // (Packs do not trigger onLoadStart or onFileStart.)
                      this._flightQueue.push(file);
                      file.loading = true;
  
                      this.loadFile(file);
                  }
                  else if (!syncblock)
                  {
                      if (!this._fileLoadStarted)
                      {
                          this._fileLoadStarted = true;
                          this.onLoadStart.dispatch();
                      }
  
                      this._flightQueue.push(file);
                      file.loading = true;
                      this.onFileStart.dispatch(this.progress, file.key, file.url);
  
                      this.loadFile(file);
                  }
              }
  
              if (!file.loaded && file.syncPoint)
              {
                  syncblock = true;
              }
  
              // Stop looking if queue full - or if syncblocked and there are no more packs.
              // (As only packs can be loaded around a syncblock)
              if (this._flightQueue.length >= inflightLimit ||
                  (syncblock && this._loadedPackCount === this._totalPackCount))
              {
                  break;
              }
          }
  
          this.updateProgress();
  
          // True when all items in the queue have been advanced over
          // (There should be no inflight items as they are complete - loaded/error.)
          if (this._processingHead >= this._fileList.length)
          {
              this.finishedLoading();
          }
          else if (!this._flightQueue.length)
          {
              // Flight queue is empty but file list is not done being processed.
              // This indicates a critical internal error with no known recovery.
              console.warn("Phaser.Loader - aborting: processing queue empty, loading may have stalled");
  
              var _this = this;
  
              setTimeout(function () {
                  _this.finishedLoading(true);
              }, 2000);
          }
  
      },
  
      /**
      * The loading is all finished.
      *
      * @method Phaser.Loader#finishedLoading
      * @private
      * @param {boolean} [abnormal=true] - True if the loading finished abnormally.
      */
      finishedLoading: function (abnormal) {
  
          if (this.hasLoaded)
          {
              return;
          }
  
          this.hasLoaded = true;
          this.isLoading = false;
  
          // If there were no files make sure to trigger the event anyway, for consistency
          if (!abnormal && !this._fileLoadStarted)
          {
              this._fileLoadStarted = true;
              this.onLoadStart.dispatch();
          }
  
          this.onLoadComplete.dispatch();
  
          this.game.state.loadComplete();
  
          this.reset();
  
      },
  
      /**
      * Informs the loader that the given file resource has been fetched and processed;
      * or such a request has failed.
      *
      * @method Phaser.Loader#asyncComplete
      * @private
      * @param {object} file
      * @param {string} [error=''] - The error message, if any. No message implies no error.
      */
      asyncComplete: function (file, errorMessage) {
  
          if (errorMessage === undefined) { errorMessage = ''; }
  
          file.loaded = true;
          file.error = !!errorMessage;
  
          if (errorMessage)
          {
              file.errorMessage = errorMessage;
  
              console.warn('Phaser.Loader - ' + file.type + '[' + file.key + ']' + ': ' + errorMessage);
          }
  
          this.processLoadQueue();
  
      },
  
      /**
      * Process pack data. This will usually modify the file list.
      *
      * @method Phaser.Loader#processPack
      * @private
      * @param {object} pack
      */
      processPack: function (pack) {
  
          var packData = pack.data[pack.key];
  
          if (!packData)
          {
              console.warn('Phaser.Loader - ' + pack.key + ': pack has data, but not for pack key');
              return;
          }
  
          for (var i = 0; i < packData.length; i++)
          {
              var file = packData[i];
  
              switch (file.type)
              {
                  case "image":
                      this.image(file.key, file.url, file.overwrite);
                      break;
  
                  case "text":
                      this.text(file.key, file.url, file.overwrite);
                      break;
  
                  case "json":
                      this.json(file.key, file.url, file.overwrite);
                      break;
  
                  case "xml":
                      this.xml(file.key, file.url, file.overwrite);
                      break;
  
                  case "script":
                      this.script(file.key, file.url, file.callback, pack.callbackContext || this);
                      break;
  
                  case "binary":
                      this.binary(file.key, file.url, file.callback, pack.callbackContext || this);
                      break;
  
                  case "spritesheet":
                      this.spritesheet(file.key, file.url, file.frameWidth, file.frameHeight, file.frameMax, file.margin, file.spacing, file.skipFrames);
                      break;
  
                  case "video":
                      this.video(file.key, file.urls);
                      break;
  
                  case "audio":
                      this.audio(file.key, file.urls, file.autoDecode);
                      break;
  
                  case "audiosprite":
                      this.audiosprite(file.key, file.urls, file.jsonURL, file.jsonData, file.autoDecode);
                      break;
  
                  case "tilemap":
                      this.tilemap(file.key, file.url, file.data, Phaser.Tilemap[file.format]);
                      break;
  
                  case "physics":
                      this.physics(file.key, file.url, file.data, Phaser.Loader[file.format]);
                      break;
  
                  case "bitmapFont":
                      this.bitmapFont(file.key, file.textureURL, file.atlasURL, file.atlasData, file.xSpacing, file.ySpacing);
                      break;
  
                  case "atlasJSONArray":
                      this.atlasJSONArray(file.key, file.textureURL, file.atlasURL, file.atlasData);
                      break;
  
                  case "atlasJSONHash":
                      this.atlasJSONHash(file.key, file.textureURL, file.atlasURL, file.atlasData);
                      break;
  
                  case "atlasXML":
                      this.atlasXML(file.key, file.textureURL, file.atlasURL, file.atlasData);
                      break;
  
                  case "atlas":
                      this.atlas(file.key, file.textureURL, file.atlasURL, file.atlasData, Phaser.Loader[file.format]);
                      break;
  
                  case "shader":
                      this.shader(file.key, file.url, file.overwrite);
                      break;
              }
          }
  
      },
  
      /**
      * Transforms the asset URL.
      *
      * The default implementation prepends the baseURL if the url doesn't begin with http or //
      *
      * @method Phaser.Loader#transformUrl
      * @protected
      * @param {string} url - The url to transform.
      * @param {object} file - The file object being transformed.
      * @return {string} The transformed url. In rare cases where the url isn't specified it will return false instead.
      */
      transformUrl: function (url, file) {
  
          if (!url)
          {
              return false;
          }
  
          if (url.match(/^(?:blob:|data:|http:\/\/|https:\/\/|\/\/)/))
          {
              return url;
          }
          else
          {
              return this.baseURL + file.path + url;
          }
  
      },
  
      /**
      * Start fetching a resource.
      *
      * All code paths, async or otherwise, from this function must return to `asyncComplete`.
      *
      * @method Phaser.Loader#loadFile
      * @private
      * @param {object} file
      */
      loadFile: function (file) {
  
          //  Image or Data?
          switch (file.type)
          {
              case 'packfile':
                  this.xhrLoad(file, this.transformUrl(file.url, file), 'text', this.fileComplete);
                  break;
  
              case 'image':
              case 'spritesheet':
              case 'textureatlas':
              case 'bitmapfont':
                  this.loadImageTag(file);
                  break;
  
              case 'audio':
                  file.url = this.getAudioURL(file.url);
  
                  if (file.url)
                  {
                      //  WebAudio or Audio Tag?
                      if (this.game.sound.usingWebAudio)
                      {
                          this.xhrLoad(file, this.transformUrl(file.url, file), 'arraybuffer', this.fileComplete);
                      }
                      else if (this.game.sound.usingAudioTag)
                      {
                          this.loadAudioTag(file);
                      }
                  }
                  else
                  {
                      this.fileError(file, null, 'No supported audio URL specified or device does not have audio playback support');
                  }
                  break;
  
              case 'video':
                  file.url = this.getVideoURL(file.url);
  
                  if (file.url)
                  {
                      if (file.asBlob)
                      {
                          this.xhrLoad(file, this.transformUrl(file.url, file), 'blob', this.fileComplete);
                      }
                      else
                      {
                          this.loadVideoTag(file);
                      }
                  }
                  else
                  {
                      this.fileError(file, null, 'No supported video URL specified or device does not have video playback support');
                  }
                  break;
  
              case 'json':
  
                  this.xhrLoad(file, this.transformUrl(file.url, file), 'text', this.jsonLoadComplete);
                  break;
  
              case 'xml':
  
                  this.xhrLoad(file, this.transformUrl(file.url, file), 'text', this.xmlLoadComplete);
                  break;
  
              case 'tilemap':
  
                  if (file.format === Phaser.Tilemap.TILED_JSON)
                  {
                      this.xhrLoad(file, this.transformUrl(file.url, file), 'text', this.jsonLoadComplete);
                  }
                  else if (file.format === Phaser.Tilemap.CSV)
                  {
                      this.xhrLoad(file, this.transformUrl(file.url, file), 'text', this.csvLoadComplete);
                  }
                  else
                  {
                      this.asyncComplete(file, "invalid Tilemap format: " + file.format);
                  }
                  break;
  
              case 'text':
              case 'script':
              case 'shader':
              case 'physics':
                  this.xhrLoad(file, this.transformUrl(file.url, file), 'text', this.fileComplete);
                  break;
  
              case 'texture':
  
                  if (file.key.split('_').pop() === 'truecolor')
                  {
                      this.loadImageTag(file);
                  }
                  break;
  
              case 'binary':
                  this.xhrLoad(file, this.transformUrl(file.url, file), 'arraybuffer', this.fileComplete);
                  break;
          }
  
      },
  
      /**
      * Continue async loading through an Image tag.
      * @private
      */
      loadImageTag: function (file) {
          var _this = this;
  
          file.data = new Image();
          file.data.name = file.key;
  
          if (this.crossOrigin)
          {
              file.data.crossOrigin = this.crossOrigin;
          }
  
          file.data.onload = function () {
              if (file.data.onload)
              {
                  file.data.onload = null;
                  file.data.onerror = null;
                  _this.fileComplete(file);
              }
          };
  
          file.data.onerror = function () {
              if (file.data.onload)
              {
                  file.data.onload = null;
                  file.data.onerror = null;
                  _this.fileError(file);
              }
          };
  
          file.data.src = this.transformUrl(file.url, file);
  
          // Image is immediately-available/cached
          // Special Firefox magic, exclude from cached reload
          // More info here: https://github.com/photonstorm/phaser/issues/2534
          if (!this.game.device.firefox && file.data.complete && file.data.width && file.data.height)
          {
              file.data.onload = null;
              file.data.onerror = null;
              this.fileComplete(file);
          }
  
      },
  
      /**
      * Continue async loading through a Video tag.
      * @private
      */
      loadVideoTag: function (file) {
  
          var _this = this;
  
          file.data = document.createElement("video");
          file.data.name = file.key;
          file.data.controls = false;
          file.data.autoplay = false;
  
          var videoLoadEvent = function () {
  
              file.data.removeEventListener(file.loadEvent, videoLoadEvent, false);
              file.data.onerror = null;
              file.data.canplay = true;
              Phaser.GAMES[_this.game.id].load.fileComplete(file);
  
          };
  
          file.data.onerror = function () {
              file.data.removeEventListener(file.loadEvent, videoLoadEvent, false);
              file.data.onerror = null;
              file.data.canplay = false;
              _this.fileError(file);
          };
  
          file.data.addEventListener(file.loadEvent, videoLoadEvent, false);
  
          file.data.src = this.transformUrl(file.url, file);
          file.data.load();
  
      },
  
      /**
      * Continue async loading through an Audio tag.
      * @private
      */
      loadAudioTag: function (file) {
  
          var _this = this;
  
          if (this.game.sound.touchLocked)
          {
              //  If audio is locked we can't do this yet, so need to queue this load request. Bum.
              file.data = new Audio();
              file.data.name = file.key;
              file.data.preload = 'auto';
              file.data.src = this.transformUrl(file.url, file);
  
              this.fileComplete(file);
          }
          else
          {
              file.data = new Audio();
              file.data.name = file.key;
  
              var playThroughEvent = function () {
                  file.data.removeEventListener('canplaythrough', playThroughEvent, false);
                  file.data.onerror = null;
                  _this.fileComplete(file);
              };
  
              file.data.onerror = function () {
                  file.data.removeEventListener('canplaythrough', playThroughEvent, false);
                  file.data.onerror = null;
                  _this.fileError(file);
              };
  
              file.data.preload = 'auto';
              file.data.src = this.transformUrl(file.url, file);
              file.data.addEventListener('canplaythrough', playThroughEvent, false);
              file.data.load();
          }
  
      },
  
      /**
      * Starts the xhr loader.
      *
      * This is designed specifically to use with asset file processing.
      *
      * @method Phaser.Loader#xhrLoad
      * @private
      * @param {object} file - The file/pack to load.
      * @param {string} url - The URL of the file.
      * @param {string} type - The xhr responseType.
      * @param {function} onload - The function to call on success. Invoked in `this` context and supplied with `(file, xhr)` arguments.
      * @param {function} [onerror=fileError]  The function to call on error. Invoked in `this` context and supplied with `(file, xhr)` arguments.
      */
      xhrLoad: function (file, url, type, onload, onerror) {
  
          if (this.useXDomainRequest && window.XDomainRequest)
          {
              this.xhrLoadWithXDR(file, url, type, onload, onerror);
              return;
          }
  
          var xhr = new XMLHttpRequest();
          xhr.open("GET", url, true);
          xhr.responseType = type;
  
          if (this.headers['requestedWith'] !== false)
          {
              xhr.setRequestHeader('X-Requested-With', this.headers['requestedWith']);
          }
  
          if (this.headers[file.type])
          {
              xhr.setRequestHeader('Accept', this.headers[file.type]);
          }
  
          onerror = onerror || this.fileError;
  
          var _this = this;
  
          xhr.onload = function () {
  
              try {
                  if (xhr.readyState === 4 && xhr.status >= 400 && xhr.status <= 599) { // Handle HTTP status codes of 4xx and 5xx as errors, even if xhr.onerror was not called.
                      return onerror.call(_this, file, xhr);
                  }
                  else {
                      return onload.call(_this, file, xhr);
                  }
              } catch (e) {
  
                  //  If this was the last file in the queue and an error is thrown in the create method
                  //  then it's caught here, so be sure we don't carry on processing it
  
                  if (!_this.hasLoaded)
                  {
                      _this.asyncComplete(file, e.message || 'Exception');
                  }
                  else
                  {
                      if (window['console'])
                      {
                          console.error(e);
                      }
                  }
              }
          };
  
          xhr.onerror = function () {
  
              try {
  
                  return onerror.call(_this, file, xhr);
  
              } catch (e) {
  
                  if (!_this.hasLoaded)
                  {
                      _this.asyncComplete(file, e.message || 'Exception');
                  }
                  else
                  {
                      if (window['console'])
                      {
                          console.error(e);
                      }
                  }
  
              }
          };
  
          file.requestObject = xhr;
          file.requestUrl = url;
  
          xhr.send();
  
      },
  
      /**
      * Starts the xhr loader - using XDomainRequest.
      * This should _only_ be used with IE 9. Phaser does not support IE 8 and XDR is deprecated in IE 10.
      *
      * This is designed specifically to use with asset file processing.
      *
      * @method Phaser.Loader#xhrLoad
      * @private
      * @param {object} file - The file/pack to load.
      * @param {string} url - The URL of the file.
      * @param {string} type - The xhr responseType.
      * @param {function} onload - The function to call on success. Invoked in `this` context and supplied with `(file, xhr)` arguments.
      * @param {function} [onerror=fileError]  The function to call on error. Invoked in `this` context and supplied with `(file, xhr)` arguments.
      * @deprecated This is only relevant for IE 9.
      */
      xhrLoadWithXDR: function (file, url, type, onload, onerror) {
  
          // Special IE9 magic .. only
          if (!this._warnedAboutXDomainRequest &&
              (!this.game.device.ie || this.game.device.ieVersion >= 10))
          {
              this._warnedAboutXDomainRequest = true;
              console.warn("Phaser.Loader - using XDomainRequest outside of IE 9");
          }
  
          // Ref: http://blogs.msdn.com/b/ieinternals/archive/2010/05/13/xdomainrequest-restrictions-limitations-and-workarounds.aspx
          var xhr = new window.XDomainRequest();
          xhr.open('GET', url, true);
          xhr.responseType = type;
  
          // XDomainRequest has a few quirks. Occasionally it will abort requests
          // A way to avoid this is to make sure ALL callbacks are set even if not used
          // More info here: http://stackoverflow.com/questions/15786966/xdomainrequest-aborts-post-on-ie-9
          xhr.timeout = 3000;
  
          onerror = onerror || this.fileError;
  
          var _this = this;
  
          xhr.onerror = function () {
              try {
                  return onerror.call(_this, file, xhr);
              } catch (e) {
                  _this.asyncComplete(file, e.message || 'Exception');
              }
          };
  
          xhr.ontimeout = function () {
              try {
                  return onerror.call(_this, file, xhr);
              } catch (e) {
                  _this.asyncComplete(file, e.message || 'Exception');
              }
          };
  
          xhr.onprogress = function() {};
  
          xhr.onload = function () {
              try {
                  if (xhr.readyState === 4 && xhr.status >= 400 && xhr.status <= 599) { // Handle HTTP status codes of 4xx and 5xx as errors, even if xhr.onerror was not called.
                      return onerror.call(_this, file, xhr);
                  }
                  else {
                      return onload.call(_this, file, xhr);
                  }
                  return onload.call(_this, file, xhr);
              } catch (e) {
                  _this.asyncComplete(file, e.message || 'Exception');
              }
          };
  
          file.requestObject = xhr;
          file.requestUrl = url;
  
          //  Note: The xdr.send() call is wrapped in a timeout to prevent an issue with the interface where some requests are lost
          //  if multiple XDomainRequests are being sent at the same time.
          setTimeout(function () {
              xhr.send();
          }, 0);
  
      },
  
      /**
      * Give a bunch of URLs, return the first URL that has an extension this device thinks it can play.
      *
      * It is assumed that the device can play "blob:" or "data:" URIs - There is no mime-type checking on data URIs.
      *
      * @method Phaser.Loader#getVideoURL
      * @private
      * @param {object[]|string[]} urls - See {@link #video} for format.
      * @return {string} The URL to try and fetch; or null.
      */
      getVideoURL: function (urls) {
  
          for (var i = 0; i < urls.length; i++)
          {
              var url = urls[i];
              var videoType;
  
              if (url.uri) // {uri: .., type: ..} pair
              {
                  videoType = url.type;
                  url = url.uri;
  
                  if (this.game.device.canPlayVideo(videoType))
                  {
                      return url;
                  }
              }
              else
              {
                  // Assume direct-data URI can be played if not in a paired form; select immediately
                  if (url.indexOf("blob:") === 0 || url.indexOf("data:") === 0)
                  {
                      return url;
                  }
  
                  if (url.indexOf("?") >= 0) // Remove query from URL
                  {
                      url = url.substr(0, url.indexOf("?"));
                  }
  
                  var extension = url.substr((Math.max(0, url.lastIndexOf(".")) || Infinity) + 1);
  
                  videoType = extension.toLowerCase();
  
                  if (this.game.device.canPlayVideo(videoType))
                  {
                      return urls[i];
                  }
              }
          }
  
          return null;
  
      },
  
      /**
      * Give a bunch of URLs, return the first URL that has an extension this device thinks it can play.
      *
      * It is assumed that the device can play "blob:" or "data:" URIs - There is no mime-type checking on data URIs.
      *
      * @method Phaser.Loader#getAudioURL
      * @private
      * @param {object[]|string[]} urls - See {@link #audio} for format.
      * @return {string} The URL to try and fetch; or null.
      */
      getAudioURL: function (urls) {
  
          if (this.game.sound.noAudio)
          {
              return null;
          }
  
          for (var i = 0; i < urls.length; i++)
          {
              var url = urls[i];
              var audioType;
  
              if (url.uri) // {uri: .., type: ..} pair
              {
                  audioType = url.type;
                  url = url.uri;
  
                  if (this.game.device.canPlayAudio(audioType))
                  {
                      return url;
                  }
              }
              else
              {
                  // Assume direct-data URI can be played if not in a paired form; select immediately
                  if (url.indexOf("blob:") === 0 || url.indexOf("data:") === 0)
                  {
                      return url;
                  }
  
                  if (url.indexOf("?") >= 0) // Remove query from URL
                  {
                      url = url.substr(0, url.indexOf("?"));
                  }
  
                  var extension = url.substr((Math.max(0, url.lastIndexOf(".")) || Infinity) + 1);
  
                  audioType = extension.toLowerCase();
  
                  if (this.game.device.canPlayAudio(audioType))
                  {
                      return urls[i];
                  }
              }
          }
  
          return null;
  
      },
  
      /**
      * Error occurred when loading a file.
      *
      * @method Phaser.Loader#fileError
      * @private
      * @param {object} file
      * @param {?XMLHttpRequest} xhr - XHR request, unspecified if loaded via other means (eg. tags)
      * @param {string} reason
      */
      fileError: function (file, xhr, reason) {
  
          var url = file.requestUrl || this.transformUrl(file.url, file);
          var message = 'error loading asset from URL ' + url;
  
          if (!reason && xhr)
          {
              reason = xhr.status;
          }
  
          if (reason)
          {
              message = message + ' (' + reason + ')';
          }
  
          this.asyncComplete(file, message);
  
      },
  
      /**
      * Called when a file has been downloaded and needs to be processed further.
      *
      * @method Phaser.Loader#fileComplete
      * @private
      * @param {object} file - File loaded
      * @param {?XMLHttpRequest} xhr - XHR request, unspecified if loaded via other means (eg. tags)
      */
      fileComplete: function (file, xhr) {
  
          var loadNext = true;
  
          switch (file.type)
          {
              case 'packfile':
  
                  // Pack data must never be false-ish after it is fetched without error
                  var data = JSON.parse(xhr.responseText);
                  file.data = data || {};
                  break;
  
              case 'texture':
  
                  if (file.data !== null)
                  {
                      this.cache.addCompressedTextureMetaData(file.key, file.url, file.url.split('.').pop().toLowerCase(), file.data);
                  }
                  else
                  {
                      this.cache.addCompressedTextureMetaData(file.key, file.url, file.url.split('.').pop().toLowerCase(), xhr.response);
                  }
                  break;
  
              case 'image':
  
                  this.cache.addImage(file.key, file.url, file.data);
                  break;
  
              case 'spritesheet':
  
                  this.cache.addSpriteSheet(file.key, file.url, file.data, file.frameWidth, file.frameHeight, file.frameMax, file.margin, file.spacing, file.skipFrames);
                  break;
  
              case 'textureatlas':
  
                  if (file.atlasURL == null)
                  {
                      this.cache.addTextureAtlas(file.key, file.url, file.data, file.atlasData, file.format);
                  }
                  else
                  {
                      //  Load the JSON or XML before carrying on with the next file
                      loadNext = false;
  
                      if (file.format === Phaser.Loader.TEXTURE_ATLAS_JSON_ARRAY || file.format === Phaser.Loader.TEXTURE_ATLAS_JSON_HASH || file.format === Phaser.Loader.TEXTURE_ATLAS_JSON_PYXEL)
                      {
                          this.xhrLoad(file, this.transformUrl(file.atlasURL, file), 'text', this.jsonLoadComplete);
                      }
                      else if (file.format === Phaser.Loader.TEXTURE_ATLAS_XML_STARLING)
                      {
                          this.xhrLoad(file, this.transformUrl(file.atlasURL, file), 'text', this.xmlLoadComplete);
                      }
                      else
                      {
                          throw new Error("Phaser.Loader. Invalid Texture Atlas format: " + file.format);
                      }
                  }
                  break;
  
              case 'bitmapfont':
  
                  if (!file.atlasURL)
                  {
                      this.cache.addBitmapFont(file.key, file.url, file.data, file.atlasData, file.atlasType, file.xSpacing, file.ySpacing);
                  }
                  else
                  {
                      //  Load the XML before carrying on with the next file
                      loadNext = false;
                      this.xhrLoad(file, this.transformUrl(file.atlasURL, file), 'text', function (file, xhr) {
                          var json;
  
                          try
                          {
                              // Try to parse as JSON, if it fails, then it's hopefully XML
                              json = JSON.parse(xhr.responseText);
                          }
                          catch (e) {}
  
                          if (!!json)
                          {
                              file.atlasType = 'json';
                              this.jsonLoadComplete(file, xhr);
                          }
                          else
                          {
                              file.atlasType = 'xml';
                              this.xmlLoadComplete(file, xhr);
                          }
                      });
                  }
                  break;
  
              case 'video':
  
                  if (file.asBlob)
                  {
                      try
                      {
                          file.data = xhr.response;
                      }
                      catch (e)
                      {
                          throw new Error("Phaser.Loader. Unable to parse video file as Blob: " + file.key);
                      }
                  }
  
                  this.cache.addVideo(file.key, file.url, file.data, file.asBlob);
                  break;
  
              case 'audio':
  
                  if (this.game.sound.usingWebAudio)
                  {
                      file.data = xhr.response;
  
                      this.cache.addSound(file.key, file.url, file.data, true, false);
  
                      if (file.autoDecode)
                      {
                          this.game.sound.decode(file.key);
                      }
                  }
                  else
                  {
                      this.cache.addSound(file.key, file.url, file.data, false, true);
                  }
                  break;
  
              case 'text':
                  file.data = xhr.responseText;
                  this.cache.addText(file.key, file.url, file.data);
                  break;
  
              case 'shader':
                  file.data = xhr.responseText;
                  this.cache.addShader(file.key, file.url, file.data);
                  break;
  
              case 'physics':
                  var data = JSON.parse(xhr.responseText);
                  this.cache.addPhysicsData(file.key, file.url, data, file.format);
                  break;
  
              case 'script':
                  file.data = document.createElement('script');
                  file.data.language = 'javascript';
                  file.data.type = 'text/javascript';
                  file.data.defer = false;
                  file.data.text = xhr.responseText;
                  document.head.appendChild(file.data);
                  if (file.callback)
                  {
                      file.data = file.callback.call(file.callbackContext, file.key, xhr.responseText);
                  }
                  break;
  
              case 'binary':
                  if (file.callback)
                  {
                      file.data = file.callback.call(file.callbackContext, file.key, xhr.response);
                  }
                  else
                  {
                      file.data = xhr.response;
                  }
  
                  this.cache.addBinary(file.key, file.data);
  
                  break;
          }
  
          if (loadNext)
          {
              this.asyncComplete(file);
          }
  
      },
  
      /**
      * Successfully loaded a JSON file - only used for certain types.
      *
      * @method Phaser.Loader#jsonLoadComplete
      * @private
      * @param {object} file - File associated with this request
      * @param {XMLHttpRequest} xhr
      */
      jsonLoadComplete: function (file, xhr) {
  
          var data = JSON.parse(xhr.responseText);
  
          if (file.type === 'tilemap')
          {
              this.cache.addTilemap(file.key, file.url, data, file.format);
          }
          else if (file.type === 'bitmapfont')
          {
              this.cache.addBitmapFont(file.key, file.url, file.data, data, file.atlasType, file.xSpacing, file.ySpacing);
          }
          else if (file.type === 'json')
          {
              this.cache.addJSON(file.key, file.url, data);
          }
          else
          {
              this.cache.addTextureAtlas(file.key, file.url, file.data, data, file.format);
          }
  
          this.asyncComplete(file);
      },
  
      /**
      * Successfully loaded a CSV file - only used for certain types.
      *
      * @method Phaser.Loader#csvLoadComplete
      * @private
      * @param {object} file - File associated with this request
      * @param {XMLHttpRequest} xhr
      */
      csvLoadComplete: function (file, xhr) {
  
          var data = xhr.responseText;
  
          this.cache.addTilemap(file.key, file.url, data, file.format);
  
          this.asyncComplete(file);
  
      },
  
      /**
      * Successfully loaded an XML file - only used for certain types.
      *
      * @method Phaser.Loader#xmlLoadComplete
      * @private
      * @param {object} file - File associated with this request
      * @param {XMLHttpRequest} xhr
      */
      xmlLoadComplete: function (file, xhr) {
  
          // Always try parsing the content as XML, regardless of actually response type
          var data = xhr.responseText;
          var xml = this.parseXml(data);
  
          if (!xml)
          {
              var responseType = xhr.responseType || xhr.contentType; // contentType for MS-XDomainRequest
              console.warn('Phaser.Loader - ' + file.key + ': invalid XML (' + responseType + ')');
              this.asyncComplete(file, "invalid XML");
              return;
          }
  
          if (file.type === 'bitmapfont')
          {
              this.cache.addBitmapFont(file.key, file.url, file.data, xml, file.atlasType, file.xSpacing, file.ySpacing);
          }
          else if (file.type === 'textureatlas')
          {
              this.cache.addTextureAtlas(file.key, file.url, file.data, xml, file.format);
          }
          else if (file.type === 'xml')
          {
              this.cache.addXML(file.key, file.url, xml);
          }
  
          this.asyncComplete(file);
  
      },
  
      /**
      * Parses string data as XML.
      *
      * @method Phaser.Loader#parseXml
      * @private
      * @param {string} data - The XML text to parse
      * @return {?XMLDocument} Returns the xml document, or null if such could not parsed to a valid document.
      */
      parseXml: function (data) {
  
          var xml;
  
          try
          {
              if (window['DOMParser'])
              {
                  var domparser = new DOMParser();
                  xml = domparser.parseFromString(data, "text/xml");
              }
              else
              {
                  xml = new ActiveXObject("Microsoft.XMLDOM");
                  // Why is this 'false'?
                  xml.async = 'false';
                  xml.loadXML(data);
              }
          }
          catch (e)
          {
              xml = null;
          }
  
          if (!xml || !xml.documentElement || xml.getElementsByTagName("parsererror").length)
          {
              return null;
          }
          else
          {
              return xml;
          }
  
      },
  
      /**
      * Update the loading sprite progress.
      *
      * @method Phaser.Loader#nextFile
      * @private
      * @param {object} previousFile
      * @param {boolean} success - Whether the previous asset loaded successfully or not.
      */
      updateProgress: function () {
  
          if (this.preloadSprite)
          {
              if (this.preloadSprite.direction === 0)
              {
                  this.preloadSprite.rect.width = Math.floor((this.preloadSprite.width / 100) * this.progress);
              }
              else
              {
                  this.preloadSprite.rect.height = Math.floor((this.preloadSprite.height / 100) * this.progress);
              }
  
              if (this.preloadSprite.sprite)
              {
                  this.preloadSprite.sprite.updateCrop();
              }
              else
              {
                  //  We seem to have lost our sprite - maybe it was destroyed?
                  this.preloadSprite = null;
              }
          }
  
      },
  
      /**
      * Returns the number of files that have already been loaded, even if they errored.
      *
      * @method Phaser.Loader#totalLoadedFiles
      * @protected
      * @return {number} The number of files that have already been loaded (even if they errored)
      */
      totalLoadedFiles: function () {
  
          return this._loadedFileCount;
  
      },
  
      /**
      * Returns the number of files still waiting to be processed in the load queue. This value decreases as each file in the queue is loaded.
      *
      * @method Phaser.Loader#totalQueuedFiles
      * @protected
      * @return {number} The number of files that still remain in the load queue.
      */
      totalQueuedFiles: function () {
  
          return this._totalFileCount - this._loadedFileCount;
  
      },
  
      /**
      * Returns the number of asset packs that have already been loaded, even if they errored.
      *
      * @method Phaser.Loader#totalLoadedPacks
      * @protected
      * @return {number} The number of asset packs that have already been loaded (even if they errored)
      */
      totalLoadedPacks: function () {
  
          return this._totalPackCount;
  
      },
  
      /**
      * Returns the number of asset packs still waiting to be processed in the load queue. This value decreases as each pack in the queue is loaded.
      *
      * @method Phaser.Loader#totalQueuedPacks
      * @protected
      * @return {number} The number of asset packs that still remain in the load queue.
      */
      totalQueuedPacks: function () {
  
          return this._totalPackCount - this._loadedPackCount;
  
      }
  
  };
  
  /**
  * The non-rounded load progress value (from 0.0 to 100.0).
  *
  * A general indicator of the progress.
  * It is possible for the progress to decrease, after `onLoadStart`, if more files are dynamically added.
  *
  * @name Phaser.Loader#progressFloat
  * @property {number}
  */
  Object.defineProperty(Phaser.Loader.prototype, "progressFloat", {
  
      get: function () {
          var progress = (this._loadedFileCount / this._totalFileCount) * 100;
          return Phaser.Math.clamp(progress || 0, 0, 100);
      }
  
  });
  
  /**
  * The rounded load progress percentage value (from 0 to 100). See {@link Phaser.Loader#progressFloat}.
  *
  * @name Phaser.Loader#progress
  * @property {integer}
  */
  Object.defineProperty(Phaser.Loader.prototype, "progress", {
  
      get: function () {
          return Math.round(this.progressFloat);
      }
  
  });
  
  Phaser.Loader.prototype.constructor = Phaser.Loader;
  