topical media & game development
[] readme course(s) preface I 1 2 II 3 4 III 5 6 7 IV 8 9 10 V 11 12 afterthought(s) appendix reference(s) example(s) resource(s) _

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animation-ch09-Bubbles.ax

animation-ch09-Bubbles.ax [swf] [flash] flex

package -- bubble(s)


  package
  {
   import flash.display.Sprite;
   import flash.events.Event;

class


   
   public class @ax-animation-ch09-Bubbles extends Sprite
   {
    private var balls:Array;
    private var numBalls:Number = 10;
    private var centerBall:animation_ch09_Ball;
    private var bounce:Number = -1;
    private var spring:Number = 0.2;

constructor


    
    public function @ax-animation-ch09-Bubbles()
    {
     init();
    }

init(s)


    
    private function init():void
    {
     balls = new Array();
     centerBall = new animation_ch09_Ball(100, 0xcccccc);
     addChild(centerBall);
     centerBall.x = stage.stageWidth / 2;
     centerBall.y = stage.stageHeight / 2;

balls


     for(var i:uint = 0; i < numBalls; i++)
     {
      var ball:animation_ch09_Ball = new animation_ch09_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);
     }

install listener


     
     addEventListener(Event.ENTER_FRAME, onEnterFrame);   
    }

animation / frame(s)


    private function onEnterFrame(event:Event):void
    {
     for(var i:uint = 0; i < numBalls; i++)
     {
      var ball:animation_ch09_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;

check distance(s)


      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;
      }
     }
    }

move(s)


    private function move(ball:animation_ch09_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;
     }

and bounce if necessary


     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;
     }

in all directions


     else if(ball.y - ball.radius < 0)
     {
      ball.y = ball.radius;
      ball.vy *= bounce;
     }
    }
   }
  }
[] readme course(s) preface I 1 2 II 3 4 III 5 6 7 IV 8 9 10 V 11 12 afterthought(s) appendix reference(s) example(s) resource(s) _

(C) Æliens 04/09/2009

You may not copy or print any of this material without explicit permission of the author or the publisher. In case of other copyright issues, contact the author.