好的，首先让我说这是我的第一个AS3项目。我对Java很好，所以OOP和继承对我来说并不陌生。 我真的花了好几个小时坐在这里，思考为什么我的代码不像我想要的那样工作。 我开始用炮塔试图射击子弹。但是，即使x和y坐标仍在变化，子弹也不会被绘制到屏幕上。 创建子弹/抛射物的方法称为OnMouseClick。 这是我的代码：
public class Main extends Sprite
{
public var projectileArr : Array = new Array(); //array which the projectile objects are stored
public var projCount : Number = 0; //projectile counter
public var curX:Number; //mouse coords
public var curY:Number;
private var tri1:Sprite = new Sprite();
private var tri1Height:Number = 50;
private var rect1:Sprite = new Sprite();
private var rect1W:Number = 2;
private var rect1H:Number = 10;
private var angle:Number = 0;
private var acceleration:Number = 0;
public var triSpeedX:Number = 0;
public var triSpeedY:Number = 0;
public var turretAngle:Number ;
//keyboard booleans
private var leftDown:Boolean = false, rightDown:Boolean = false, upDown:Boolean = false, downDown:Boolean = false;
public function Main():void
{
if (stage)
init();
else
addEventListener(Event.ADDED_TO_STAGE, init);
}
private function init(e:Event = null):void
{
removeEventListener(Event.ADDED_TO_STAGE, init);
// entry point
//draw triangle
addChild(tri1);
tri1.graphics.lineStyle(1, 0xff00ff00);
tri1.graphics.beginFill(0xff0000);
tri1.graphics.moveTo(0, -tri1Height / 2)
tri1.graphics.lineTo(tri1Height / 3, +tri1Height / 2);
tri1.graphics.lineTo(-tri1Height / 3, +tri1Height / 2);
tri1.graphics.endFill();
tri1.x = 400;
tri1.y = 300;
//draw turret
addChild(rect1);
rect1.graphics.beginFill(0xFFFFFF);
rect1.graphics.moveTo(rect1W / 2, -rect1H);
rect1.graphics.lineTo(rect1W / 2, 0);
rect1.graphics.lineTo(-rect1W / 2, 0);
rect1.graphics.lineTo(-rect1W / 2, -rect1H);
rect1.graphics.endFill();
rect1.x = tri1.x;
rect1.y = tri1.y;
stage.addEventListener(KeyboardEvent.KEY_UP, onUp);
stage.addEventListener(KeyboardEvent.KEY_DOWN, onDown);
stage.addEventListener(Event.ENTER_FRAME, Run);
stage.addEventListener(MouseEvent.MOUSE_MOVE, getMouseCoord);
stage.addEventListener(MouseEvent.MOUSE_DOWN, OnMouseClick);
}
//creation of projectile on click
public function OnMouseClick (e:MouseEvent):void
{
projectileArr[projCount] = new Projectile (rect1.x, rect1.y, turretAngle); //create a new projectile object
addChild(projectileArr [projCount]); //... then it doesn't display
projCount++;
trace ("BAM");
}
public function getMouseCoord(e:MouseEvent):void
{
curX = mouseX;
curY = mouseY;
}
public function onUp(e:KeyboardEvent):void
{
if (e.keyCode == Keyboard.LEFT)
leftDown = false;
else if (e.keyCode == Keyboard.RIGHT)
rightDown = false;
if (e.keyCode == Keyboard.UP)
upDown = false;
else if (e.keyCode == Keyboard.DOWN)
downDown = false;
}
public function onDown(e:KeyboardEvent):void
{
if (e.keyCode == Keyboard.LEFT)
leftDown = true;
else if (e.keyCode == Keyboard.RIGHT)
rightDown = true;
if (e.keyCode == Keyboard.UP)
upDown = true;
else if (e.keyCode == Keyboard.DOWN)
downDown = true;
}
public function addProjToScreen (projectile:Projectile) : void
{
addChild(projectile);
}
private function Run(e:Event):void
{
acceleration = 0; //resets acceleration back to 0 to limit speed
if (leftDown)
{
angle -= 5;
}
else if (rightDown)
{
angle += 5;
}
if (upDown)
{
acceleration += 3;
}
else if (downDown)
{
acceleration -= 3;
}
triSpeedX += acceleration * Math.cos(angle * Math.PI / 180);
triSpeedY += acceleration * Math.sin(angle * Math.PI / 180);
tri1.x += triSpeedX;
tri1.y += triSpeedY;
//borders
if (tri1.x < 0)
{
triSpeedX *= -.5;
tri1.x = 0 ;
}
if (tri1.x > 800 )
{
tri1.x = 800;
triSpeedX *= -.5;
}
if (tri1.y < 0)
{
triSpeedY *= -.5;
tri1.y = 0 ;
}
if (tri1.y > 600)
{
triSpeedY *= -.5;
tri1.y = 600;
}
//friction
triSpeedX *= 0.95
triSpeedY *= 0.95
rect1.x = tri1.x;
rect1.y = tri1.y;
var xCurDist:Number = curX - rect1.x;
var yCurDist:Number = curY - rect1.y;
turretAngle = Math.atan(yCurDist / xCurDist) * 180 / Math.PI ;
if (xCurDist < 0 )
{
turretAngle += 180;
}
if (xCurDist > 0 && yCurDist < 0 )
{
turretAngle += 360;
}
rect1.rotation= turretAngle + 90; // + 90 to account for the sprite originally pointing up, which is 270 degrees ccw
tri1.rotation = angle + 90;
for (var i:int = 0 ; i < projCount ; i ++)
{
projectileArr [i].move();
}
}
}
和弹丸类：
public class Projectile extends MovieClip
{
private var projectile : Sprite = new Sprite();
private var speed: int = 10;
private var angle :Number;
private var xIncr: Number;
private var yIncr: Number;
public function Projectile(x:Number, y:Number, angle:Number)
{
this.x = x;
this.y = y;
this.angle = angle;
projectile.graphics.beginFill (0xFF0000);
projectile.graphics.drawCircle (x, y, 4);
projectile.graphics.endFill() ;
xIncr = speed * Math.cos (angle); // angle needs to be converted to radians
yIncr = speed * Math.sin (angle);
}
public function move () :void
{
trace (this.x + " " + this.y);
this.x += xIncr;
this.y += yIncr;
}
}
我只是不知道我错过了什么......我正在为所有新创建的对象调用addChild，还有什么可以做的？
答案 0 :(得分：2)
您没有在构造函数中将精灵抛射物添加到Projectile的置换列表中。
addChild(projectile);
此外，你在你的射弹类中加倍x和y坐标。通过将projectile.graphics.drawCircle (x, y, 4);更改为projectile.graphics.drawCircle (0, 0, 4);