/*
* 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
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* @exports ImageTile
*/
define([
'../error/ArgumentError',
'../util/Logger',
'../render/TextureTile',
'../util/Tile'
],
function (ArgumentError,
Logger,
TextureTile,
Tile) {
"use strict";
/**
* Constructs an image tile.
* @alias ImageTile
* @constructor
* @classdesc Represents an image applied to a portion of a globe's terrain. Applications typically do not
* interact with this class.
* @augments TextureTile
* @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.
* @param {String} imagePath The full path to the image.
* @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 ImageTile = function (sector, level, row, column, imagePath) {
if (!imagePath || (imagePath.length < 1)) {
throw new ArgumentError(
Logger.logMessage(Logger.LEVEL_SEVERE, "ImageTile", "constructor",
"The specified image path is null, undefined or zero length."));
}
TextureTile.call(this, sector, level, row, column); // args are checked in the superclass' constructor
/**
* This tile's image path.
* @type {String}
*/
this.imagePath = imagePath;
/**
* The tile whose texture to use when this tile's texture is not available.
* @type {Matrix}
*/
this.fallbackTile = null;
// Assign imagePath to gpuCacheKey (inherited from TextureTile).
this.gpuCacheKey = imagePath;
};
ImageTile.prototype = Object.create(TextureTile.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.
*/
ImageTile.prototype.size = function () {
return this.__proto__.__proto__.size.call(this) + this.imagePath.length + 8;
};
/**
* 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.
*/
ImageTile.prototype.bind = function (dc) {
// Attempt to bind in TextureTile first.
var isBound = this.__proto__.__proto__.bind.call(this, dc);
if (isBound) {
return true;
}
if (this.fallbackTile) {
return this.fallbackTile.bind(dc);
}
return false;
};
/**
* If this tile's fallback texture is used, applies the appropriate texture transform to a specified matrix.
* @param {DrawContext} dc The current draw context.
* @param {Matrix} matrix The matrix to apply the transform to.
*/
ImageTile.prototype.applyInternalTransform = function (dc, matrix) {
if (this.fallbackTile && !(dc.gpuResourceCache.resourceForKey(this.imagePath))) {
// Must apply a texture transform to map the tile's sector into its fallback's image.
this.applyFallbackTransform(matrix);
}
};
// Intentionally not documented.
ImageTile.prototype.applyFallbackTransform = function (matrix) {
var deltaLevel = this.level.levelNumber - this.fallbackTile.level.levelNumber;
if (deltaLevel <= 0)
return;
var fbTileDeltaLat = this.fallbackTile.sector.deltaLatitude(),
fbTileDeltaLon = this.fallbackTile.sector.deltaLongitude(),
sx = this.sector.deltaLongitude() / fbTileDeltaLon,
sy = this.sector.deltaLatitude() / fbTileDeltaLat,
tx = (this.sector.minLongitude - this.fallbackTile.sector.minLongitude) / fbTileDeltaLon,
ty = (this.sector.minLatitude - this.fallbackTile.sector.minLatitude) / fbTileDeltaLat;
// Apply a transform to the matrix that maps texture coordinates for this tile to texture coordinates for the
// fallback tile. Rather than perform the full set of matrix operations, a single multiply is performed with the
// precomputed non-zero values:
//
// Matrix trans = Matrix.fromTranslation(tx, ty, 0);
// Matrix scale = Matrix.fromScale(sxy, sxy, 1);
// matrix.multiply(trans);
// matrix.multiply(scale);
matrix.multiply(
sx, 0, 0, tx,
0, sy, 0, ty,
0, 0, 1, 0,
0, 0, 0, 1);
};
return ImageTile;
});