Actionscript 3 sprite clear with alpha

Question

我想用0.1透明度清除精靈，但sprite.graphics.clear（）沒有這個選項。每幀需要不斷清除。我怎樣才能做到這一點？我嘗試用透明度爲0.1的整個舞臺上的填充矩形，但我的遊戲正在減慢每一幀。

Answer 1

也許你應該把所有的精靈放到一個Vector中，當你需要的時候你可以手動去除它們。

private var vec:Vector.<Sprite> = new Vector.<Sprite>(); 

    private function update():void 
    { 
     // reduce the alpha of all other sprites 
     // check all other sprites from the newest to the oldest (so we can make a splice without getting an index error in case of there is other sprites to remove) 
     for(var i:int = this.vec.length -1; i >= 0; i--) 
     { 
      this.vec[i].alpha -= 0.1; 

      if(this.vec[i].alpha == 0) 
      { 
       if(this.contains(this.vec[i])) 
       { 
        this.removeChild(this.vec[i]); 
       } 

       // we clear the sprite so it doesn't use any memory 
       this.vec[i].graphics.clear(); 

       // remove the sprite from the vector 
       this.vec.splice(i,1); 
      } 
     } 

     // create and draw the new sprite you want to add 
     var addingSprite:Sprite = new Sprite(); 
     addingSprite.graphics.beginFill(0x005500); 
     addingSprite.graphics.drawCircle(0, 0, 10); 

     this.addChild(addingSprite);     // add the sprite to the stage 

     this.vec.push(addingSprite);     // add the sprite to the vector so you can reduce his alpha easily 
    }