forked from: flash on 2010-3-9

/**
 * Copyright mikako ( http://wonderfl.net/user/mikako )
 * MIT License ( http://www.opensource.org/licenses/mit-license.php )
 * Downloaded from: http://wonderfl.net/c/if3E
 */

// forked from 084's flash on 2010-3-9
package {
	import flash.display.Sprite;
	import flash.events.Event;
	public class Bubbles extends Sprite {
		private var balls:Array;
		private var numBalls:Number = 10;
		private var centerBall:Ball;
		private var bounce:Number = -1;
		private var spring:Number = 0.2;
		
		public function Bubbles() {
			init();
		}
		
		private function init():void {
			balls = new Array();
			centerBall = new Ball(100, 0xcccccc);
			addChild(centerBall);
			centerBall.x = stage.stageWidth / 2;
			centerBall.y = stage.stageHeight / 2;
			
			for (var i:uint = 0; i < numBalls; i++) {
				var ball:Ball = new Ball(Math.random() * 40 + 5, Math.random() * 0xffffff);
				ball.x = Math.random() * stage.stageWidth;
				ball.y = Math.random() * stage.stageHeight;
				ball.vx = Math.random() * 6 - 3;
				ball.vy = Math.random() * 6 - 3;
				addChild(ball);
				balls.push(ball);
			}
			addEventListener(Event.ENTER_FRAME, onEnterFrame);
			
		}
		private function onEnterFrame(event:Event):void {
			for (var i:uint = 0; i < numBalls; i++) {
				var ball:Ball = balls[i];
				move(ball);
				var dx:Number = ball.x -centerBall.x;
				var dy:Number = ball.y -centerBall.y;
				var dist:Number = Math.sqrt(dx * dx +dy * dy);
				var minDist:Number = ball.radius + centerBall.radius;
				if (dist < minDist) {
					var angle:Number = Math.atan2(dy, dx);
					var tx:Number = centerBall.x + Math.cos(angle) * minDist;
					var ty:Number = centerBall.y + Math.sin(angle) * minDist;
					ball.vx += (tx - ball.x) * spring;
					ball.vy += (ty - ball.y) * spring;
				}
			}
		}
		private function move(ball:Ball):void {
			ball.x += ball.vx;
			ball.y += ball.vy;
			if (ball.x + ball.radius > stage.stageWidth) {
				ball.x = stage.stageWidth - ball.radius;
				ball.vx *= bounce;
				}else if (ball.x - ball.radius < 0) {
					ball.x = ball.radius;
					ball.vx *= bounce;
				}
				if (ball.y + ball.radius > stage.stageHeight) {
					ball.y = stage.stageHeight - ball.radius;
					ball.vy *= bounce;
					}else if (ball.y - ball.radius < 0) {
						ball.y = ball.radius;
						ball.vy *= bounce;
					}
			}
		}
	}
import flash.display.Sprite;
	 class Ball extends Sprite {
		public var radius:Number;
		public var color:uint;
		public var vx:Number = 0;
		public var vy:Number = 0;
			
		public function Ball(radius:Number = 40,color:uint=0xff0000 ):void {
			this.radius = radius;
			this.color = color;
		    init();
		}
		public function init():void {
			graphics.beginFill(color);
			graphics.drawCircle(0, 0, radius);
			graphics.endFill();
		}
	}