Question

好的，所以我有一个太空射击游戏，从上面看。当用鼠标左右移动时，船向上移动（-y）并稍微旋转。最大旋转在-10到10之间，宽度为* 0.5。为了让“子弹”朝着船所面向的方向射击，我正在尝试使用cos sin公式。只要船的旋转为-5或5（-10 * 0.5,10 * 0.5），它就能很好地工作，但是一旦旋转接近0，就会开始在整个地方开火：）

我已经读过我需要将度数转换为弧度以便能够使用cos和sin，并且我已经尝试过 - 我得到的最好结果是它只向左或向右发射，具体取决于旋转，没有角度变化。

现在我是AS的新手，所以为可理解的代码道歉：）

任何人都可以帮我弄清楚为什么角度在-5和5时工作正常，但是当它在0时关闭时会变得疯狂吗？

谢谢你们！

import flash.events.KeyboardEvent;
import flash.events.Event;

var spaceship_mc:spaceship = new spaceship();

stage.addChild(spaceship_mc);

spaceship_mc.x = stage.stageWidth / 2;
spaceship_mc.y = stage.stageHeight / 2;

stage.addEventListener(Event.ENTER_FRAME,shipMovement);


function shipMovement(event:Event):void 
{

var dx:int = spaceship_mc.x - mouseX;
var dy:int = spaceship_mc.y - mouseY;
spaceship_mc.x -= dx / 15;
spaceship_mc.y -= dy /20;


if (dx >= -10 && dx <= 0) 
{
    spaceship_mc.rotation = -dx * 0.5;
}
else if (dx >= 0 && dx <= 10) 
{
    spaceship_mc.rotation = dx * -0.5;
}
else if (dx > -10) 
{
    spaceship_mc.rotation = -10 * 0.5;
}
else if (dx < 10) 
{
    spaceship_mc.rotation = 10 * 0.5;
}


if (spaceship_mc.rotation > 0)
{
    spaceship_mc.scaleX = 1-(0.05 * spaceship_mc.rotation);
}
if (spaceship_mc.rotation < 0)
{
    spaceship_mc.scaleX = 1-(0.05 * -(spaceship_mc.rotation));
}


    if (dy >= 0 && dy < 22 )
{
    spaceship_mc.afterburner_mc.y = 22;
}
else if (dy >= 22 && dy <= 32)
{
    spaceship_mc.afterburner_mc.y = dy;
}
else if (dy > 32)
{
    spaceship_mc.afterburner_mc.y = 32;
}
else if (dy < 0)
{
    spaceship_mc.afterburner_mc.y = 22;
}


var spaceshipHalfWidth:uint = spaceship_mc.width/2;
var spaceshipHalfHeight:uint = spaceship_mc.height/2;


if (spaceship_mc.x + spaceshipHalfWidth > stage.stageWidth) 
{
    spaceship_mc.x = stage.stageWidth - spaceshipHalfWidth;
}
else if (spaceship_mc.x - spaceshipHalfWidth < 0) 
{        
    spaceship_mc.x = 0 + spaceshipHalfWidth;    
}      
if (spaceship_mc.y - spaceshipHalfHeight < 0) 
{        
    spaceship_mc.y = 0 + spaceshipHalfHeight;    
}    
else if (spaceship_mc.y + spaceshipHalfHeight > stage.stageHeight) 
{
    spaceship_mc.y = stage.stageHeight - spaceshipHalfHeight;
}
}


addEventListener(MouseEvent.CLICK, skyt);


function skyt(e:MouseEvent):void
{
nyttSkudd();
}


function nyttSkudd()
{
var leftPhoton_mc:photon = new photon();
var rightPhoton_mc:photon = new photon();

leftPhoton_mc.x = spaceship_mc.x - 25;
leftPhoton_mc.y = spaceship_mc.y - 10;

rightPhoton_mc.x = spaceship_mc.x + 16;
rightPhoton_mc.y = spaceship_mc.y - 10;

leftPhoton_mc.rotation = spaceship_mc.rotation;
rightPhoton_mc.rotation = spaceship_mc.rotation;

addChild(leftPhoton_mc);
addChild(rightPhoton_mc);
addChild(spaceship_mc);

leftPhoton_mc.addEventListener(Event.ENTER_FRAME, skudd);
rightPhoton_mc.addEventListener(Event.ENTER_FRAME, skudd);
}


function skudd(e:Event):void
{   
var photonAngle = e.target.rotation;
var photonSpeed = 10;

if (photonAngle == 0)
{
    e.target.y -= photonSpeed;
}
else if (photonAngle > 0)
{
    e.target.x += photonSpeed * Math.cos(photonAngle);
    e.target.y += photonSpeed * Math.sin(photonAngle);      
}
else if (photonAngle < 0)
{
    e.target.x -= photonSpeed * Math.cos(photonAngle);
    e.target.y -= photonSpeed * Math.sin(photonAngle);
}

if (e.target.y < 0 || e.target.y > 400)
{
    e.target.removeEventListener(Event.ENTER_FRAME, skudd);
    e.target.parent.removeChild(e.target);
}
}

Answer 1

photonAngle是度，但Math.sin / cos需要弧度。所以你需要进行以下转换。

var photonAngle = e.target.rotation * Math.PI / 180.0;

也

e.target.x += photonSpeed * Math.cos(photonAngle);
e.target.y += photonSpeed * Math.sin(photonAngle);

就足够了，你不需要if / else语句：

if (photonAngle == 0)
{
    e.target.y -= photonSpeed;
}
else if (photonAngle > 0)
{
    e.target.x += photonSpeed * Math.cos(photonAngle);
    e.target.y += photonSpeed * Math.sin(photonAngle);      
}
else if (photonAngle < 0)
{
    e.target.x -= photonSpeed * Math.cos(photonAngle);
    e.target.y -= photonSpeed * Math.sin(photonAngle);
}

祝你好运！

cos3 / sin的AS3问题 - 不会向我想要的方向发射

1 个答案: