code: function () {
  
              /**
               * The width in pixels of framebuffers associated with this controller's tiles.
               * @type {Number}
               * @readonly
               */
              this.tileWidth = 256;
  
              /**
               * The height in pixels of framebuffers associated with this controller's tiles.
               * @type {Number}
               * @readonly
               */
              this.tileHeight = 256;
  
              /**
               * Controls the level of detail switching for this controller. The next highest resolution level is
               * used when an image's texel size is greater than this number of pixels.
               * @type {Number}
               * @default 1.75
               */
              this.detailControl = 1.75;
  
              // Internal. Intentionally not documented.
              this.levels = new LevelSet(Sector.FULL_SPHERE, new Location(45, 45), 16, this.tileWidth, this.tileHeight);
  
              // Internal. Intentionally not documented.
              this.topLevelTiles = [];
  
              // Internal. Intentionally not documented.
              this.currentTiles = [];
  
              // Internal. Intentionally not documented.
              this.currentTimestamp = null;
  
              // Internal. Intentionally not documented.
              this.currentGlobeStateKey = null;
  
              // Internal. Intentionally not documented.
              this.tileCache = new MemoryCache(500000, 400000);
  
              // Internal. Intentionally not documented.
              this.key = "FramebufferTileController " + ++FramebufferTileController.keyPool;
          }
docs: Constructs a framebuffer tile controller.
  @alias FramebufferTileController
  @constructor
  @classdesc Provides access to a multi-resolution WebGL framebuffer arranged as adjacent tiles in a pyramid.
  WorldWind shapes use this class internally to draw on the terrain surface. Applications typically do not
  interact with this class.