Cleaning out old createGradientBox thingies?

programming flash
1

Here’s my question. I’m trying to create a rippling effect for use in a touch-sensitive kiosk – when the user touches the screen, I want it to create a ripple effect (a sort of replacement for the mouse cursor).

I’ve created a gradientBox on a matrix, blah blah blah, and it appears as though the animation function I’ve thrown together works – almost. I’m not sure how to erase the “old” gradientBoxes before the new one gets drawn.

Here’s the code I’m using: Just copy it and save it and set it as the document class for a new movie to test.

I would greatly appreciate any help or direction! Thanks!

package
{
    import flash.display.MovieClip;
    import flash.display.Bitmap;
    import flash.display.BitmapData;
    import flash.display.BitmapDataChannel;
    
    import flash.display.GradientType;
    
    import flash.filters.DisplacementMapFilter;
    import flash.filters.DisplacementMapFilterMode;
    
    import flash.geom.Matrix;
    import flash.geom.Point;
    
    import flash.events.*;
    import flash.ui.Mouse;
    
    public class DMFilterExample extends MovieClip
    {
        internal static var gbX:Number;
        internal static var gbY:Number;
        internal static var gbR:Number;
        
        internal static var gbD:uint;
        
        internal static var myMatrix:Matrix;
        internal static var myBitmapData:BitmapData;

        public function DMFilterExample ()
        {
            /**
             * Base all of the circle's values on these numbers: including the
             * gradientBox! The relationships here will kill the world if messed up!
             */
            gbX=200;
            gbY=200;
            gbR=75;
            
            gbD=0;
            
            buildRippler(gbR*0.5);
            this.stage.addEventListener(Event.ENTER_FRAME, animateRippler);
        }
        
        private function buildRippler (tmpGbR:Number):void
        {
            if (!tmpGbR) tmpGbR=gbR;
            
            myMatrix=new Matrix();
            myMatrix.createGradientBox(tmpGbR*2, tmpGbR*2, 0, gbX-tmpGbR, gbY-tmpGbR);
            
            var colors:Array=[0xFF0000, 0xFF0000, 0xFF0000];
            var alphas:Array=[0, 0.3, 0];
            var ratios:Array=[0, 207, 255];
            
            this.graphics.lineStyle(1, 0x000000, 0.3, false); // Debugging.
            this.graphics.beginGradientFill(GradientType.RADIAL, colors, alphas, ratios, myMatrix);
            this.graphics.drawCircle(gbX, gbY, tmpGbR);
            
            if (myBitmapData) myBitmapData.dispose();
            
            myBitmapData=new BitmapData(tmpGbR*2, tmpGbR*2, true, 0x000000)
            myBitmapData.draw(this, myMatrix);
        }
        
        public function animateRippler (e:Event):void
        {
            gbD++;
            gbD%=360;
            
            buildRippler(Math.abs(((Math.PI/180)*Math.sin(gbD)*(gbR*0.75))*(gbR)));
        }
    }
}

FYI, once I get things working, this rippler won’t be the document class…I’m just trying to take one step at a time…thanks!