/*
* Copyright 2003-2006, 2009, 2017, United States Government, as represented by the Administrator of the
* National Aeronautics and Space Administration. All rights reserved.
*
* The NASAWorldWind/WebWorldWind platform is 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 FramebufferTile
*/
define([
'../error/ArgumentError',
'../render/FramebufferTexture',
'../util/Logger',
'../geom/Matrix',
'../geom/Rectangle',
'../render/TextureTile'
],
function (ArgumentError,
FramebufferTexture,
Logger,
Matrix,
Rectangle,
TextureTile) {
"use strict";
/**
* Constructs a framebuffer tile.
* @alias FramebufferTile
* @constructor
* @augments TextureTile
* @classdesc Represents a WebGL framebuffer applied to a portion of a globe's terrain. The framebuffer's width
* and height in pixels are equal to this tile's [tileWidth]{@link FramebufferTile#tileWidth} and
* [tileHeight]{@link FramebufferTile#tileHeight}, respectively. The framebuffer can be made active by calling
* [bindFramebuffer]{@link FramebufferTile#bindFramebuffer}. Color fragments written to this
* tile's framebuffer can then be drawn on the terrain surface using a
* [SurfaceTileRenderer]{@link SurfaceTileRenderer}.
* <p>
* This class is meant to be used internally. 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.
* @param {String} cacheKey A string uniquely identifying this tile relative to other tiles.
* @throws {ArgumentError} If the specified sector or level is null or undefined, the row or column arguments
* are less than zero, or the cache name is null, undefined or empty.
*/
var FramebufferTile = function (sector, level, row, column, cacheKey) {
if (!cacheKey || (cacheKey.length < 1)) {
throw new ArgumentError(
Logger.logMessage(Logger.LEVEL_SEVERE, "FramebufferTile", "constructor",
"The specified cache name is null, undefined or zero length."));
}
TextureTile.call(this, sector, level, row, column); // args are checked in the superclass' constructor
// Assign the cacheKey as the gpuCacheKey (inherited from TextureTile).
this.gpuCacheKey = cacheKey;
// Internal. Intentionally not documented.
this.textureTransform = Matrix.fromIdentity().setToUnitYFlip();
// Internal. Intentionally not documented.
this.mustClear = true;
};
FramebufferTile.prototype = Object.create(TextureTile.prototype);
/**
* Causes this tile to clear any color fragments written to its off-screen framebuffer.
* @param dc The current draw context.
*/
FramebufferTile.prototype.clearFramebuffer = function (dc) {
this.mustClear = true;
};
/**
* Causes this tile's off-screen framebuffer as the current WebGL framebuffer. WebGL operations that affect the
* framebuffer now affect this tile's framebuffer, rather than the default WebGL framebuffer.
* Color fragments are written to this tile's WebGL texture, which can be made active by calling
* [SurfaceTile.bind]{@link SurfaceTile#bind}.
*
* @param {DrawContext} dc The current draw context.
* @returns {Boolean} true if the framebuffer was bound successfully, otherwise false.
*/
FramebufferTile.prototype.bindFramebuffer = function (dc) {
var framebuffer = dc.gpuResourceCache.resourceForKey(this.gpuCacheKey);
if (!framebuffer) {
framebuffer = this.createFramebuffer(dc);
}
dc.bindFramebuffer(framebuffer);
if (this.mustClear) {
this.doClearFramebuffer(dc);
this.mustClear = false;
}
return true;
};
// Internal. Intentionally not documented.
FramebufferTile.prototype.createFramebuffer = function (dc) {
var framebuffer = new FramebufferTexture(dc.currentGlContext, this.tileWidth, this.tileHeight, false);
dc.gpuResourceCache.putResource(this.gpuCacheKey, framebuffer, framebuffer.size);
return framebuffer;
};
// Internal. Intentionally not documented.
FramebufferTile.prototype.doClearFramebuffer = function (dc) {
var gl = dc.currentGlContext;
gl.clearColor(0, 0, 0, 0);
gl.clear(gl.COLOR_BUFFER_BIT);
};
/**
* Applies the appropriate texture transform to display this tile's WebGL texture.
* @param {DrawContext} dc The current draw context.
* @param {Matrix} matrix The matrix to apply the transform to.
*/
FramebufferTile.prototype.applyInternalTransform = function (dc, matrix) {
matrix.multiplyMatrix(this.textureTransform);
};
return FramebufferTile;
});