package
{
import flash.display.Sprite;
import flash.events.Event;
/**
* ...
* @author zkl
*/
public class Spring1 extends Sprite
{
private var ball:Ball;
private var vx:Number = 0;
private var spring:Number = 0.1;
private var friction:Number = 0.95;
private var targetX:Number = stage.stageWidth / 2;
public function Spring1():void
{
init();
}
private function init():void
{
ball = new Ball;
addChild(ball);
ball.y = stage.stageHeight / 2;
addEventListener(Event.ENTER_FRAME, EnterFrame);
}
private function EnterFrame(e:Event):void
{
//與目标點的距離:
var dx:Number = targetX - ball.x;
//下面計算加速度。加速度與距離成正比,也就是距離乘以 spring 的值
var ax:Number = dx * spring;
//把加速度加到速度向量中。
vx += ax;
//引入摩擦力
vx *= friction;
ball.x += vx;
}
}
}