package {
    import flash.display.Sprite;
    import flash.events.Event;
    import flash.text.TextField;
    import flash.text.TextFieldAutoSize;
    
    [SWF(width="465", height="465", backgroundColor="0x0", frameRate="45")]
    import flash.text.TextField;
    public class BallFollowingMouse extends Sprite {
    		private var ballCount:uint = 50;
    		private var speed:Number = 0.2;
        public function BallFollowingMouse() {
        	
        	var _txt:TextField = new TextField();
        	addChild(_txt);
        	_txt.autoSize = TextFieldAutoSize.LEFT;
        	_txt.text = new BallEvent(BallEvent.FOLLOW,0,1,2).toString();
        	
        	
        		for (var i:uint = 0; i<ballCount; i++){
        			addChild(new Ball(this,200));
        		}
            
            addEventListener(Event.ENTER_FRAME,followMouse);
        }
        
        private function followMouse(e:Event):void {
        		dispatchEvent(new BallEvent(BallEvent.FOLLOW,mouseX,mouseY,speed));
        }
    }
}

import flash.display.Sprite;
import flash.display.Graphics;
class Ball extends Sprite {
	
	private var angle:Number;
	private var radius:Number;
	private var sizeRate:Number = 0.1;
	private const deceleration:Number = 0.2;
	
	public function Ball(timeline:Sprite,maxRadius:Number){
		var randomRate:Number = Math.random();
		angle = Math.PI * 2 * Math.random();
		radius = maxRadius * randomRate;
		createBall(randomRate);
		
		timeline.addEventListener(BallEvent.FOLLOW,follow);
	}
	private function createBall(randomRate:Number):void {
		var myGraphics:Graphics = graphics;
		myGraphics.beginFill(Math.floor(0xFFFFFF * randomRate) + 1);
		myGraphics.drawCircle(0,0,radius * sizeRate);
	}
	
	private function follow(e:BallEvent):void {
		var randomRate:Number = Math.random();
		angle += e.speed;
		angle %= Math.PI * 2;
		var nX:Number = e.targetX + radius * Math.cos(angle);
		var nY:Number = e.targetY + radius * Math.sin(angle);
		x += (nX - x) * deceleration * randomRate;
		y += (nY - y) * deceleration * randomRate;
	}
}

import flash.events.Event;
class BallEvent extends Event {
	public static const FOLLOW:String = "follow";
	private var _targetX:Number;
	private var _targetY:Number;
	private var _speed:Number;
	
	public function get targetX():Number {
		return _targetX;
	}
	
	public function get targetY():Number {
		return _targetY;
	}
	
	public function get speed():Number {
		return _speed;
	}
	
	public function BallEvent(event_str:String,myTargetX:Number,myTargetY:Number,mySpeed:Number){
		super(event_str);
		_targetX = myTargetX;
		_targetY = myTargetY;
		_speed = mySpeed;
	}
	
	public override function toString():String {
		return formatToString("BallEvent","type","bubbles","cancelable","eventPhase","targetX","targetY","speed");
	}
	
	public override function clone():Event {
		return new BallEvent(type,targetX,targetY,speed);
	}
}

flash on 2010-2-19