/*
* AlphaMapFilter
* Visit http://createjs.com/ for documentation, updates and examples.
*
* Copyright (c) 2010 gskinner.com, inc.
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following
* conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
/**
* @module EaselJS
*/
// namespace:
this.createjs = this.createjs || {};
(function () {
"use strict";
// constructor:
/**
* Applies a greyscale alpha map image (or canvas) to the target, such that the alpha channel of the result will
* be copied from the red channel of the map, and the RGB channels will be copied from the target.
*
* Generally, it is recommended that you use {{#crossLink "AlphaMaskFilter"}}{{/crossLink}}, because it has much
* better performance.
*
* <h4>Example</h4>
* This example draws a red->blue box, caches it, and then uses the cache canvas as an alpha map on a 100x100 image.
*
* var box = new createjs.Shape();
* box.graphics.beginLinearGradientFill(["#ff0000", "#0000ff"], [0, 1], 0, 0, 0, 100)
* box.graphics.drawRect(0, 0, 100, 100);
* box.cache(0, 0, 100, 100);
*
* var bmp = new createjs.Bitmap("path/to/image.jpg");
* bmp.filters = [
* new createjs.AlphaMapFilter(box.cacheCanvas)
* ];
* bmp.cache(0, 0, 100, 100);
* stage.addChild(bmp);
*
* See {{#crossLink "Filter"}}{{/crossLink}} for more information on applying filters.
* @class AlphaMapFilter
* @extends Filter
* @constructor
* @param {HTMLImageElement|HTMLCanvasElement|WebGLTexture} alphaMap The greyscale image (or canvas) to use as the alpha value for the
* result. This should be exactly the same dimensions as the target.
**/
function AlphaMapFilter(alphaMap) {
this.Filter_constructor();
if (!createjs.Filter.isValidImageSource(alphaMap)) {
throw "Must provide valid image source for alpha map, see Filter.isValidImageSource";
}
// public properties:
/**
* The greyscale image (or canvas) to use as the alpha value for the result. This should be exactly the same
* dimensions as the target.
* @property alphaMap
* @type HTMLImageElement|HTMLCanvasElement
**/
this.alphaMap = alphaMap;
// private properties:
/**
* @property _map
* @protected
* @type HTMLImageElement|HTMLCanvasElement
**/
this._map = null;
/**
* @property _mapCtx
* @protected
* @type CanvasRenderingContext2D
**/
this._mapCtx = null;
/**
* @property _mapTexture
* @protected
* @type WebGLTexture
*/
this._mapTexture = null;
this.FRAG_SHADER_BODY = (
"uniform sampler2D uAlphaSampler;"+
"void main(void) {" +
"vec4 color = texture2D(uSampler, vTextureCoord);" +
"vec4 alphaMap = texture2D(uAlphaSampler, vTextureCoord);" +
// some image formats can have transparent white rgba(1,1,1, 0) when put on the GPU, this means we need a slight tweak
// using ceil ensure that the colour will be used so long as it exists but pure transparency will be treated black
"float newAlpha = alphaMap.r * ceil(alphaMap.a);" +
"gl_FragColor = vec4(clamp(color.rgb/color.a, 0.0, 1.0) * newAlpha, newAlpha);" +
"}"
);
if(alphaMap instanceof WebGLTexture) {
this._mapTexture = alphaMap;
}
}
var p = createjs.extend(AlphaMapFilter, createjs.Filter);
// TODO: deprecated
// p.initialize = function() {}; // searchable for devs wondering where it is. REMOVED. See docs for details.
// Docced in superclass
p.shaderParamSetup = function(gl, stage, shaderProgram) {
if(this._mapTexture === null) { this._mapTexture = gl.createTexture(); }
gl.activeTexture(gl.TEXTURE1);
gl.bindTexture(gl.TEXTURE_2D, this._mapTexture);
stage.setTextureParams(gl);
if (this.alphaMap !== this._mapTexture) {
gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, this.alphaMap);
}
gl.uniform1i(
gl.getUniformLocation(shaderProgram, "uAlphaSampler"),
1
);
};
// public methods:
// Docced in superclass
p.clone = function () {
var o = new AlphaMapFilter(this.alphaMap);
return o;
};
// Docced in superclass
p.toString = function () {
return "[AlphaMapFilter]";
};
// private methods:
// Docced in superclass
p._applyFilter = function (imageData) {
if (!this._prepAlphaMap()) { return false; }
var outArray = imageData.data;
var width = imageData.width;
var height = imageData.height;
var rowOffset, pixelStart;
var sampleData = this._mapCtx.getImageData(0,0, this._map.width,this._map.height);
var sampleArray = sampleData.data;
var sampleWidth = sampleData.width;
var sampleHeight = sampleData.height;
var sampleRowOffset, samplePixelStart;
var widthRatio = sampleWidth/width;
var heightRatio = sampleHeight/height;
// performance optimizing lookup
// the x and y need to stretch separately, nesting the for loops simplifies this logic even if the array is flat
for (var i=0; i<height; i++) {
rowOffset = i * width;
sampleRowOffset = ((i*heightRatio) |0) * sampleWidth;
// the arrays are int arrays, so a single pixel is [r,g,b,a, ...],so calculate the start of the pixel
for (var j=0; j<width; j++) {
pixelStart = (rowOffset + j) *4;
samplePixelStart = (sampleRowOffset + ((j*widthRatio) |0)) *4;
// modify the pixels
outArray[pixelStart] = outArray[pixelStart];
outArray[pixelStart+1] = outArray[pixelStart+1];
outArray[pixelStart+2] = outArray[pixelStart+2];
outArray[pixelStart+3] = sampleArray[samplePixelStart];
}
}
return true;
};
/**
* @method _prepAlphaMap
* @protected
**/
p._prepAlphaMap = function () {
if (!this.alphaMap) { return false; }
if (this.alphaMap === this._map && this._mapCtx) { return true; }
var map = this._map = this.alphaMap;
var canvas = map;
var ctx;
if (map instanceof HTMLCanvasElement) {
ctx = canvas.getContext("2d");
} else {
canvas = createjs.createCanvas ? createjs.createCanvas() : document.createElement("canvas");
canvas.width = map.width;
canvas.height = map.height;
ctx = canvas.getContext("2d");
ctx.drawImage(map, 0, 0);
}
this._mapCtx = ctx;
return true;
};
createjs.AlphaMapFilter = createjs.promote(AlphaMapFilter, "Filter");
}());