Java游戏旋转图像和坐标轴

Question

我用飞船做了游戏，但移动它的时候遇到了问题。 这是脚本：

public class spaceship { 

private final local_client local_client; 

private final int startX; 
private final int startY; 
private final int startR; 

private double x,y,r; 
public static double rotation; 
public static double velo; 

public static AffineTransform at;

public spaceship(local_client local_client,int startX,int startY,int startR) { 
    this.local_client = local_client; 
    this.startX = startX; 
    this.startY = startY; 
    this.startR = startR; 
    x=200; 
    y=200; 
    r=90; 
} 

public void drawImage(Graphics2D g2d) { 
    g2d.drawImage(local_client.spaceship_img,200,200, local_client.game); 
    at = g2d.getTransform(); 

       at.translate(x , y); 
         at.rotate(Math.toRadians(r)); 
      at.translate(-(local_client.spaceship_img.getWidth()/2),-(local_client.spaceship_img.getHeight()/2)); 
    System.out.println(at.getTranslateX() + " - " + at.getTranslateY()); 
       g2d.setTransform(at); 
    g2d.drawImage(local_client.spaceship_img,0,0, local_client.game); 

} 

所以用这个剧本我可以旋转图像（见屏幕）： http://gyazo.com/c982b17afbba8cdc65e7786bd1cbea47

我的问题是，如果我增加在垂直轴X或Y移动（屏幕）： http://gyazo.com/1fb2efb5aff9e95c56e7dddb6a30df4a 和不是在对角线

Answer 1

at.translate(x , y);

这行代码移动你的船周围，是否正确？增加x和y只会根据轴向上和向下移动它们。

如果您想沿着船的路径移动，您将不得不使用三角函数来计算实际的x和y来移动。

以下是大概的伪代码，应该让你朝正确的方向。取决于你的r，可能会不准确或不准确。

//drive along the ship's nose line 
void moveAlongShipAxis(int magnitude) { 
    x += magnitude * Math.cos(Math.toRadians(r)); 
    y += magnitude * Math.sin(Math.toRadians(r));  
} 
//strafe left and right, if you have that, otherwise you can skip this one 
void moveYAlongTransverseAxis(int magnitude) { 
    y += magnitude * Math.cos(Math.toRadians(r)); 
    x += magnitude * Math.sin(Math.toRadians(r));  
}