as3雪花飞舞

package {

import flash.display.*;
import flash.events.*;
import flash.utils.Timer;
public class Snow extends MovieClip { 
private var snowArray:Array;
private var num:Number = 70;
private var snowTimer:Timer;

public function Snow() {
snowArray = new Array();
for (var i:uint =0; i<num; i++) {
var scale = Math.random()*1.2 + 0.2;
snowArray[i] = new snow();
snowArray[i].scaleX = scale;
snowArray[i].scaleY = scale;
snowArray[i].x = Math.random()*550;
snowArray[i].y = -Math.random()*400;
snowArray[i].rotation=Math.random()*360;
snowArray[i].v = Math.random()*2 + 2;
snowArray[i].dir = Math.random()*180;
addChild(snowArray[i]);
}
this.addEventListener(Event.ENTER_FRAME,motionSnow);
/*snowTimer = new Timer(80,0);
snowTimer.addEventListener("timer",motionSnow);
snowTimer.start();*/
}

private function motionSnow(e:Event){
//private function motionSnow(e:TimerEvent){
for (var i:uint = 0; i < num; i++) {
snowArray[i].x += Math.cos(snowArray[i].dir);
snowArray[i].y += snowArray[i].v;
if (snowArray[i].x > 550) snowArray[i].x = 0;
if (snowArray[i].x < 0) snowArray[i].x = 550;
if (snowArray[i].y > 400) snowArray[i].y = 0;
}
}
}
}