lots of balls

/**
 * Copyright wexler ( http://wonderfl.net/user/wexler )
 * MIT License ( http://www.opensource.org/licenses/mit-license.php )
 * Downloaded from: http://wonderfl.net/c/fWCk
 */

package {
    import flash.display.Sprite;
    import flash.events.Event;
    import flash.events.MouseEvent;
    import flash.geom.*;
    import flash.utils.getTimer;
    import net.hires.debug.Stats;
    
    [SWF(width = "400", height = "400", frameRate = "60", backgroundColor = "#7F7F7F")]

    public class mySprite extends Sprite {
        private const _size:uint = 500;
        private const _n_dots:uint = 500;
        private const _r_min:Number = 0.475;
        private const _r_max:Number = 0.95;
        private const _radius:uint = 7;
        private const _speed:Number = (10*Math.PI/180)/1000.0;    // in radians/msec
        //private const _frames:uint = 2;
        private const _fp_radius:uint = 4;
        private var _dots:Array = new Array(_n_dots);
        private var _stats:* = undefined;
        public function mySprite() {
            randomize();
            addEventListener(Event.ENTER_FRAME, update);
            stage.addEventListener(MouseEvent.MOUSE_DOWN, mouse_listener);
        }
        
        public function mouse_listener(e:MouseEvent):void
        {
            if(!e.shiftKey) {
                randomize();
            }
            else {
                if(_stats) {
                    removeChild(_stats);
                    _stats = undefined;
                }
                else {
                    _stats = addChild(new Stats());
                }
            }
        }

        private function randomize():void {
            const z:Number = Math.pow(_r_min/_r_max, 2);
            const u:Number = 1 - z;
            for(var i:uint = 0; i < _n_dots; i++) {
                var r:Number = Math.sqrt(z + u*Math.random())*_r_max;
                var th:Number = Math.random()*2*Math.PI;
                var gray:uint = Math.random()*256;
                _dots[i] = new dot(r, th, gray + 256*gray + 65536*gray);
            }
        }
  
        public function update(e:Event):void
        {
            const theta0:Number = getTimer()*_speed;
            graphics.clear();
            for each(var p:dot in _dots) {
                const x:Number = (1 + p.r*Math.cos(p.theta + theta0))*_size/2;
                const y:Number = (1 - p.r*Math.sin(p.theta + theta0))*_size/2;
                this.graphics.beginFill(p.color);
                this.graphics.drawCircle(x, y, _radius);
                graphics.endFill();
            }
            this.graphics.beginFill(0xFF0000);
            this.graphics.drawCircle(_size/2, _size/2, _fp_radius);
            graphics.endFill();
        }
    }
}

class dot 
{ 
    public var r:Number;
    public var theta:Number;
    public var color:uint;
    public function dot(R:Number, Theta:Number, Color:uint)
    {
        r = R;
        theta = Theta,
        color = Color;
    }
}