package hcmair.starling.effects
{
    import flash.display3D.Context3D;
    import flash.display3D.Context3DProgramType;

    import starling.rendering.FilterEffect;
    import starling.rendering.Program;

    public class ColorMaskEffect extends FilterEffect
    {
        private var _offsets:Vector.<Number>;

        public function ColorMaskEffect()
        {
            _offsets = new Vector.<Number>(2, true);
        }

        override protected function createProgram():Program
        {
            var vertexShader:String = STD_VERTEX_SHADER;
            var fragmentShader:String =
                "tex ft0, v0, fs0 <2d, linear> \n" + // read the pixel
                "sub ft1, ft1, ft1 \n" + // fill ft1 with zero
                "sge ft0.w, ft0.w, ft1.w \n" + // set the alpha to 1 if greater than zero
                "mov oc, ft0" // move it to the output

            return Program.fromSource(vertexShader, fragmentShader);
        }

        override protected function beforeDraw(context:Context3D):void
        {
            context.setProgramConstantsFromVector(Context3DProgramType.FRAGMENT, 0, _offsets);
            super.beforeDraw(context);
        }

        public function get maskColor():uint { return _offsets[0]; }
        public function set maskColor(value:uint):void { _offsets[0] = value; }

        public function get alphaOffset():Number { return _offsets[1]; }
        public function set alphaOffset(value:Number):void { _offsets[1] = value; }
    }
}