Flash Native As3 基礎總整理(1-3)Bitmap與BitmapData

使用Shape()做特效..
Sprite 物件是顯示物件容器，而 Shape 物件則不是 (而且也不包含子顯示物件)。因此，Shape物件耗用的記憶體比 Sprite 物件 (都包含相同的圖像)少.. 小小煙火特效demo

/**
* ...
* @author Ray Cheng
*/
[SWF(frameRate = "30", width = "800", height = "600", backgroundColor = "0x000000")]
public class BitmapEffectDemo extends Sprite 
{
 private var _timer:Timer;
 private var _ratius:uint = 200;       //--半徑
 private var _circleNum:uint = 36;     //--煙火數量
 private var _angle:Number;
  
 public function BitmapEffectDemo() 
 {
   _angle = Math.PI * 2 / _circleNum;
   _timer = new Timer(2000, 0);
   _timer.addEventListener(TimerEvent.TIMER, onTimerCompleteHandler);
   _timer.start()
 }
  
 private function onTimerCompleteHandler(e:TimerEvent):void 
 {
   for (var i:uint = 0; i < 3; i++)
   {
     var $mcCircle:Shape = new Shape(); 
     $mcCircle.graphics.beginGradientFill
            (GradientType.RADIAL, 
            ["0x" + Math.floor(Math.random() * 999999), "0x000000"], 
            [1, 0], 
            [0, 50]);
     $mcCircle.graphics.drawCircle( 0, 0, 20);
     $mcCircle.graphics.endFill();
     $mcCircle.cacheAsBitmap = true;
     $mcCircle.x = 800 / 2;
     $mcCircle.y = 600 + $mcCircle.height;
     addChild($mcCircle);
     TweenMax.to($mcCircle, .5, { y:200 , delay:0.2 * i, 
            onCompleteParams:[$mcCircle], onComplete:onTweenComplete } );
    }
 }
  
 private function onTweenComplete(pCircle:Shape):void 
 {
    removeChild(pCircle)
    for (var i:uint = 0; i < _circleNum; i++)
    {
  //trace(i)
      var $circle:Shape = new Shape();
      $circle.graphics.beginGradientFill(
             GradientType.RADIAL,
             ["0x" + Math.floor(Math.random() * 999999),
             "0x000000"],
             [1, 0],
             [0, 50]);
      $circle.graphics.drawCircle(0, 0, 20);
      $circle.graphics.endFill();
      $circle.x = 800 / 2;
      $circle.y = 200;
      $circle.rotationZ = 360 / _circleNum * i;
      addChild($circle)
      TweenMax.to($circle, .3, { x:Math.cos(_angle * i) * _ratius + 400,
             y:Math.sin(_angle * i) * _ratius + 200,
             scaleX:1.5 , 
             scaleY:0.5, 
             alpha:0 ,
             onCompleteParams:[$circle], 
             onComplete:function(pCircle:Shape):void {
     removeChild(pCircle);
    }} );
     }
   
 }