actionscript-3 - 符号偶尔会卡在边缘

Question

我有一些代码，我希望一个符号(只是一个方形 atm)在舞台内弹跳。然而，有时它会卡在边缘。有关如何解决此问题的任何建议？

其他一切正常，包括惯性运动。

package  {
    import flash.display.MovieClip;
    import flash.events.*
    import flash.ui.Keyboard

    public class Unit extends MovieClip {

        var velocityX:Number = 1;
        var velocityY:Number = 1;
        var accellerationX:Number = 1;
        var accellerationY:Number = 1;
        var bounciness:Number = 1;
        var maxSpeed:Number = 10;

        public function Unit(){ 
            Key.initialize(stage);
            addEventListener("enterFrame", move);

        }

        private function move(e:Event){

            accellerate()
            if ((this.x<10)||(this.x>780)){
                velocityX *= -1;
                    if (velocityX>0){
                    velocityX -= bounciness;
                }
                if (velocityX<0){
                    velocityX += bounciness;
                }
                this.x += velocityX;
            }
            else{
                this.x += velocityX;
            }
            if ((this.y<10)||(this.y>520)){
                velocityY *= -1;
                if (velocityY>0){
                    velocityY -= bounciness;
                }
                if (velocityY<0){
                    velocityY += bounciness;
                }
                this.y += velocityY;
            }
            else {
            this.y += velocityY;
            }
        }

        private function accellerate(){

            if (Math.abs(velocityY) < maxSpeed){
                if (Key.isDown(Keyboard.UP)){
                    velocityY -= accellerationY;
                    trace("Accellerating UP");
                }
                if (Key.isDown(Keyboard.DOWN)){
                    velocityY += accellerationY;
                    trace("Accellerating DOWN");
                }
            }
            if (Math.abs(velocityX) < maxSpeed){
                if (Key.isDown(Keyboard.RIGHT)){
                    velocityX += accellerationX;
                    trace("Accellerating RIGHT");
                }
                if (Key.isDown(Keyboard.LEFT)){
                    velocityX -= accellerationX;
                    trace("Accellerating LEFT");
                }
            }
            if (Key.isDown(Keyboard.SPACE)){
                velocityX = 0;
                velocityY = 0;
        }

        }
    }

}

Answer 1

您的问题如下:

if ((this.x<10)||(this.x>780)){
    velocityX *= -1;

你切换了 volocityX，但可能会在下一帧发生，它仍然满足 if 条件(没有向另一个方向移动足够远)所以它只是在每一帧从 -1 到 1 来回移动.

改为做这样的事情:

if(this.x < 10 && velocity == -1) velocity = 1;  //If it's near the left edge, and still moving to the left, change direction
if(this.x > 780 && velocity == 1) velocity = -1;

这样，您只会在方向错误时改变方向。

重复 velocityY 的东西