Flash AS2如何阻止字符移出屏幕+移动和旋转代码

Question

嘿，下面是我移动我的角色player_mc的代码，它工作得很好，他在屏幕上完美地移动，但我不能想出一个办法来阻止他离开屏幕。据我所知，如果playermc = x>舞台宽度减少5增加5等，y也是如此，但为什么这对我不起作用?你们能告诉我我哪里做错了吗?您可以看到标记为不能作为注释工作的代码。谢谢，如果你想看到完整的代码，这里有一个链接到我问的另一个问题:https://stackoverflow.com/questions/16764305/educational-simulation-actionscript-2

   function rotatePlayer()
    {
        //calculate player_mc rotation, based on player position & mouse position 
        player_mc._rotation = Math.atan2(_ymouse - player_mc._y, _xmouse - player_mc._x) * radians2;
        // not working code: stage collision.
    if (player_mc._x > stage.width)
    {
        player_mc._x+50
    }
    if (Key.isDown(Key.RIGHT))
    {
    player_mc._x += 5; 
    }
    else if (Key.isDown(Key.LEFT))
    {
    player_mc._x -= 5;
    }
    else if (Key.isDown(Key.UP))
    {
    player_mc._y -= 5;
    }
    else if (Key.isDown(Key.DOWN))
    {
    player_mc._y += 5;
    }
    }

Answer 1

如果我理解正确的话，您想要这样的内容:

if (player_mc._x > stage.width)
        {
            player_mc._x = stage.width
        }
if (player_mc._x < 0) {
    player_mc._x = 0;
}

Answer 2

同样，在AS2中，Stage需要大写，所以它读起来应该是

if (player_mc._x > Stage.width) {
    player_mc._x= Stage.width;
}
else if (player_mc._x < 0) {
    player_mc._x = 0;
}
if (player_mc._y > Stage.height) {
    player_mc._y= Stage.height;
}
else if (player_mc._y < 0) {
    player_mc._y = 0;
}

将此代码放在Key下面。isDown部分，而不是上面，否则在添加另一个增量之前纠正超调会产生奇怪的反弹效果。最后，你可能想要在边界中减去/添加播放器mc宽度的一半，这样一半的宽度就不会消失。