Source: render/TextureTile.js

 * Copyright 2015-2017 WorldWind Contributors
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * @exports TextureTile
    function (ArgumentError,
              Tile) {
        "use strict";

         * Constructs a texture tile.
         * @alias TextureTile
         * @constructor
         * @augments Tile
         * @classdesc Represents an image applied to a portion of a globe's terrain. Applications typically do not
         * interact with this class.
         * @param {Sector} sector The sector this tile covers.
         * @param {Level} level The level this tile is associated with.
         * @param {Number} row This tile's row in the associated level.
         * @param {Number} column This tile's column in the associated level.
         * @throws {ArgumentError} If the specified sector or level is null or undefined, the row or column arguments
         * are less than zero, or the specified image path is null, undefined or empty.
        var TextureTile = function (sector, level, row, column) {
  , sector, level, row, column); // args are checked in the superclass' constructor

             * GPU cache key
             * @type {string}
            this.gpuCacheKey = null;

        TextureTile.prototype = Object.create(Tile.prototype);

         * Returns the size of the this tile in bytes.
         * @returns {Number} The size of this tile in bytes, not including the associated texture size.
        TextureTile.prototype.size = function () {

         * Causes this tile's texture to be active. Implements [SurfaceTile.bind]{@link SurfaceTile#bind}.
         * @param {DrawContext} dc The current draw context.
         * @returns {Boolean} true if the texture was bound successfully, otherwise false.
        TextureTile.prototype.bind = function (dc) {
            var texture = dc.gpuResourceCache.resourceForKey(this.gpuCacheKey);
            if (texture) {
                return texture.bind(dc);

            return false;

         * If this tile's fallback texture is used, applies the appropriate texture transform to a specified matrix.
         * Otherwise, this is a no-op.
         * @param {DrawContext} dc The current draw context.
         * @param {Matrix} matrix The matrix to apply the transform to.
        TextureTile.prototype.applyInternalTransform = function (dc, matrix) {
            // Override this method if the tile has a fallback texture.

        return TextureTile;