How to Use Masks, the Blur Effect and Timer Events in AS3

This is a little demo I created to help familiarize myself with some of the special effects available in AS3. It started off as a stage light sweeping in random directions across the background image. The stage light was created by drawing a circle and applying that as the "mask" for the background image. The stage light expands and contracts by changing the scaleX and scaleY of the circle by random values.

I later decided to add a "blur" effect, which is a filter available via the BlurFilter class in AS3. Once you create an instance of BlurFilter, you can pass it on to a display object by placing it into an array. Code is presented below.

I used the same image for the background as the Hotdog Guitar demo.

package {

import flash.display.Sprite;
import flash.display.Bitmap;
import flash.display.BitmapData;
import flash.utils.Timer;
import flash.events.TimerEvent;
import flash.filters.BlurFilter;

public class StageLight extends Sprite {

// this is how you add MyStage.jpg from library to AS3
var bdStage : BitmapData = new MyStage(600, 400);
var bStage : Bitmap = new Bitmap(bdStage);
var circle : Sprite = new Sprite;
var tSweep : Timer = new Timer(30, 50); // about 30 frames per second

var blur : BlurFilter = new BlurFilter();
var filterArray = new Array();

var startX : int = Math.random() * 600; // x coordinate
var startY : int = Math.random() * 400; // y coordinate
var startR : int = 1 + Math.random() * 5; // radius 1..5 of original size
var startB : int = 10 + Math.random() * 20; // blur filter 10..30

var destX : int = Math.random() * 600;
var destY : int = Math.random() * 400;
var destR : int = 1 + Math.random() * 5;
var destB : int = 0;


public function StageLight() {

}

// creates a new destination point for the stage light
public function newSweep(e : TimerEvent) {

}

// continues the current sweep of the light
public function doSweep(e : TimerEvent) {

}

}

}