#

API Docs for: 2.0.0
Show: Inherited Protected Private Deprecated

# File: src/pixi/filters/AlphaMaskFilter.js

    /**
     * @author Mat Groves http://matgroves.com/ @Doormat23
     */

    /**
     * The AlphaMaskFilter class uses the pixel values from the specified texture (called the displacement map) to perform a displacement of an object.
     * You can use this filter to apply all manor of crazy warping effects
     * Currently the r property of the texture is used to offset the x and the g property of the texture is used to offset the y.
     *
     * @class AlphaMaskFilter
     * @extends AbstractFilter
     * @constructor
     * @param texture {Texture} The texture used for the displacement map * must be power of 2 texture at the moment
     */
    PIXI.AlphaMaskFilter = function(texture)
    {
        PIXI.AbstractFilter.call( this );

        this.passes = [this];
        texture.baseTexture._powerOf2 = true;

        // set the uniforms
        this.uniforms = {
            mask: {type: 'sampler2D', value:texture},
            mapDimensions:   {type: '2f', value:{x:1, y:5112}},
            dimensions:   {type: '4fv', value:[0,0,0,0]}
        };

        if(texture.baseTexture.hasLoaded)
        {
            this.uniforms.mask.value.x = texture.width;
            this.uniforms.mask.value.y = texture.height;
        }
        else
        {
            this.boundLoadedFunction = this.onTextureLoaded.bind(this);

            texture.baseTexture.on('loaded', this.boundLoadedFunction);
        }

        this.fragmentSrc = [
            'precision mediump float;',
            'varying vec2 vTextureCoord;',
            'varying vec4 vColor;',
            'uniform sampler2D mask;',
            'uniform sampler2D uSampler;',
            'uniform vec2 offset;',
            'uniform vec4 dimensions;',
            'uniform vec2 mapDimensions;',

            'void main(void) {',
            '   vec2 mapCords = vTextureCoord.xy;',
            '   mapCords += (dimensions.zw + offset)/ dimensions.xy ;',
            '   mapCords.y *= -1.0;',
            '   mapCords.y += 1.0;',
            '   mapCords *= dimensions.xy / mapDimensions;',

            '   vec4 original =  texture2D(uSampler, vTextureCoord);',
            '   float maskAlpha =  texture2D(mask, mapCords).r;',
            '   original *= maskAlpha;',
            //'   original.rgb *= maskAlpha;',
            '   gl_FragColor =  original;',
            //'   gl_FragColor = gl_FragColor;',
            '}'
        ];
    };

    PIXI.AlphaMaskFilter.prototype = Object.create( PIXI.AbstractFilter.prototype );
    PIXI.AlphaMaskFilter.prototype.constructor = PIXI.AlphaMaskFilter;

    /**
     * Sets the map dimensions uniforms when the texture becomes available.
     *
     * @method onTextureLoaded
     */
    PIXI.AlphaMaskFilter.prototype.onTextureLoaded = function()
    {
        this.uniforms.mapDimensions.value.x = this.uniforms.mask.value.width;
        this.uniforms.mapDimensions.value.y = this.uniforms.mask.value.height;

        this.uniforms.mask.value.baseTexture.off('loaded', this.boundLoadedFunction);
    };

    /**
     * The texture used for the displacement map. Must be power of 2 sized texture.
     *
     * @property map
     * @type Texture
     */
    Object.defineProperty(PIXI.AlphaMaskFilter.prototype, 'map', {
        get: function() {
            return this.uniforms.mask.value;
        },
        set: function(value) {
            this.uniforms.mask.value = value;
        }
    });