//
// Source code for the shader:
//
<languageVersion : 1.0;>

kernel RedGradientFilter
<
    namespace: "Adobe::Example";
    vendor: "Adobe examples";
    version: 1;
    description: "Applies a gradient across the red channel of the input image.";
>
{
    input image4 src;
    output pixel4 dst;
    
    parameter float width
    <
        description: "The width of the image to which the shader is applied.";
        minValue: 0.0;
    >;

    void evaluatePixel()
    {
        pixel4 temp = sampleNearest(src, outCoord());
        temp.r = 1.0 - (outCoord().x * (1.0 / width));
        dst = temp;
    }
}

//
// ActionScript source code:
//
package {
    import flash.display.Shader;
    import flash.display.Sprite;
    import flash.events.Event;
    import flash.filters.ShaderFilter;
    import flash.net.URLLoader;
    import flash.net.URLLoaderDataFormat;
    import flash.net.URLRequest;

    public class ShaderFilterExample extends Sprite {
        
        private var loader:URLLoader;
        private var s:Sprite;
        
        public function ShaderFilterExample() {
            loader = new URLLoader();
            loader.dataFormat = URLLoaderDataFormat.BINARY;
            loader.addEventListener(Event.COMPLETE, loadCompleteHandler);
            loader.load(new URLRequest("gradient.pbj"));
            
            s = new Sprite();
            s.graphics.beginFill(0x009900);
            s.graphics.drawCircle(100, 100, 100);
            addChild(s);
        }
        
        private function loadCompleteHandler(event:Event):void {
            var shader:Shader = new Shader(loader.data);
            shader.data.width.value = [s.width];
            
            var gradientFilter:ShaderFilter = new ShaderFilter(shader);
            s.filters = [gradientFilter];
        }
    }
}