Question

我是ActionScript3的新手，正在制作小行星类游戏。现在，当您松开移动按钮时，船将继续沿直线漂浮，我希望能够阻止这种情况的发生。我在考虑或者是专用的制动按钮（例如b键），或者如果没有按下该键以停止运动，则以较容易的方式进行。就像我说的那样，我真的是AS3的新手，所以甚至不确定我的代码的哪一部分正在使它们保持直线飞行。这是控制运动的代码供参考：

// register key presses
        public function keyDownFunction(event:KeyboardEvent) {
            if (event.keyCode == 37) {
                    leftArrow = true;
            } else if (event.keyCode == 39) {
                    rightArrow = true;
            } else if (event.keyCode == 38) {
                    upArrow = true;
            //Add event listener for down arrow
            } else if (event.keyCode == 40) {
                    downArrow = true;
                    // show thruster
                    if (gameMode == "play") ship.gotoAndStop(2);
            } else if (event.keyCode == 32) { // space
                    var channel:SoundChannel = shootSound.play();
                    newMissile();
            } else if (event.keyCode == 90) { // z
                    startShield(false);
                    var channel:SoundChannel = shieldSound.play();
            }
        }

        // register key ups
        public function keyUpFunction(event:KeyboardEvent) {
            if (event.keyCode == 37) {
                leftArrow = false;
            } else if (event.keyCode == 39) {
                rightArrow = false;
            } else if (event.keyCode == 38) {
                upArrow = false;
            //Add listener for down arrow
            } else if (event.keyCode == 40) {
                downArrow = false;
                // remove thruster
                if (gameMode == "play") ship.gotoAndStop(1);
            }
        }

        // animate ship
        public function moveShip(timeDiff:uint) {

            // rotate and thrust
            if (leftArrow) {
                ship.rotation -= shipRotationSpeed*timeDiff;
            } else if (rightArrow) {
                ship.rotation += shipRotationSpeed*timeDiff;
            } else if (upArrow) {
                shipMoveX += Math.cos(Math.PI*ship.rotation/180)*thrustPower;
                shipMoveY += Math.sin(Math.PI*ship.rotation/180)*thrustPower;
                //Added down arrow movement to allow player to move backwards
            } else if (downArrow) {
                shipMoveX -= Math.cos(Math.PI*ship.rotation/180)*thrustPower;
                shipMoveY -= Math.sin(Math.PI*ship.rotation/180)*thrustPower;
            }

            // move
            ship.x += shipMoveX;
            ship.y += shipMoveY;

Answer 1

我同意您的代码中存在一些逻辑问题。您的船将继续行驶直到审判日，因为两个变量决定了它的运动速度-shipMoveX 和shipMoveY-不会随着时间的推移而自动降级。

现在实际上有成千上万种方法可以实现，但是让我们保持现状简单。您正在使用名为 thrustPower 的类变量-确保将其设置为 0.1 ，并且确保 shipMoveX 和 shipMoveY < / strong>为 0 。另外添加以下类变量：

private var thrustHorizontal:Number = 0; private var thrustVertical:Number = 0; private var speed:Number = 0; private var maxSpeed:Number = 5; private var decay:Number = 0.97;

用以下方法替换moveShip函数：

public function moveShip(timeDiff:uint):void { thrustHorizontal = Math.sin(Math.PI * ship.rotation / 180); thrustVertical = Math.cos(Math.PI * ship.rotation / 180); // rotate and thrust if (leftArrow) { ship.rotation -= shipRotationSpeed * timeDiff; } else if (rightArrow) { ship.rotation += shipRotationSpeed * timeDiff; } else if (upArrow) { shipMoveX += thrustPower * thrustHorizontal; shipMoveY += thrustPower * thrustVertical; } else if (downArrow) { shipMoveX -= thrustPower * thrustHorizontal; shipMoveY -= thrustPower * thrustVertical; } if (!upArrow && !downArrow) { shipMoveX *= decay; shipMoveY *= decay; } speed = Math.sqrt((shipMoveX * shipMoveX) + (shipMoveY * shipMoveY)); if (speed > maxSpeed) { shipMoveX *= maxSpeed / speed; shipMoveY *= maxSpeed / speed; } ship.x += shipMoveX; ship.y -= shipMoveY; }

如您所见，有一个新的if块：

if (!upArrow && !downArrow) { shipMoveX *= decay; shipMoveY *= decay; }

如果玩家既不向上也不向下并乘以衰变使飞船的水平/垂直速度。如果向后滚动一点，您会注意到它的值为 0.97 。通常可以说，如果将正数x乘以0
因此，如果您是Spaship，则当前以每帧3像素的水平移动（shipMoveX = 3； shipMoveY = 0）下一帧将变为2.91。下一个帧将是2.8227，然后是2.738019 ...依此类推，直到它最终达到无穷大零为止。

ActionScript3：应该使用什么代码阻止播放器控制的精灵移动？

1 个答案: