Merge branch 'master' into palette-swap-filter

Gruntfile.js

@@ -80,6 +80,7 @@ module.exports = function(grunt) {
             '<%= dirs.src %>/filters/DotScreenFilter.js',
             '<%= dirs.src %>/filters/CrossHatchFilter.js',
             '<%= dirs.src %>/filters/RGBSplitFilter.js',
+            '<%= dirs.src %>/filters/PaletteFilter.js',
             '<%= dirs.src %>/Outro.js'
         ],
         banner = [

src/pixi/filters/PaletteFilter.js

@@ -0,0 +1,58 @@
+/**
+ * @author Mat Groves http://matgroves.com/ @Doormat23
+ */
+
+PIXI.PaletteFilter = function(paletteTexture, paletteWidth)
+{
+    PIXI.AbstractFilter.call(this);
+
+    this.passes = [this];
+
+    // set the uniforms
+    this.uniforms = {
+        palette: { type: 'sampler2D', value: paletteTexture },
+        width: { type: '1f', value: paletteWidth },
+        widthInv: { type: '1f', value: 1 / paletteWidth }
+    };
+
+    this.fragmentSrc = [
+        'precision mediump float;',
+        'varying vec2 vTextureCoord;',
+        'varying vec4 vColor;',
+        'uniform sampler2D uSampler;',
+        'uniform sampler2D palette;',
+        'uniform float width;',
+        'uniform float widthInv;',
+
+        'void main() {',
+        '   float index = texture2D(uSampler, vTextureCoord).r * 255.0;', //Red holds index into palette
+        '   vec2 coord = vec2(', //convert index into coords in palette texture
+        '       mod(index, width) * widthInv,',
+        '       (index / width) * widthInv',
+        '   );',
+        '   gl_FragColor = texture2D(palette, coord);', //Read color from palette and output
+        '}'
+    ];
+};
+
+PIXI.PaletteFilter.prototype = Object.create( PIXI.AbstractFilter.prototype );
+PIXI.PaletteFilter.prototype.constructor = PIXI.PaletteFilter;
+
+Object.defineProperty(PIXI.PaletteFilter.prototype, 'palette', {
+    get: function() {
+        return this.uniforms.palette.value;
+    },
+    set: function(value) {
+        this.uniforms.palette.value = value;
+    }
+});
+
+Object.defineProperty(PIXI.PaletteFilter.prototype, 'width', {
+    get: function() {
+        return this.uniforms.width.value;
+    },
+    set: function(value) {
+        this.uniforms.width.value = value;
+        this.uniforms.widthInv.value = 1 / value;
+    }
+});