LibGDX实现敌人延迟射击及解决子弹不显示问题求助

在LibGDX开发中，实现敌人向玩家发射直线飞行子弹的功能，但子弹未在PlayState中显示。以下是Ghost类代码：

public class Ghost {
    private Texture topGhost, bottomGhost;
    private  Vector2 postopGhost;
    private Vector2 posBotGhost;
    private Random rand;
    private static final int fluct = 130;
    private int GhostGap;
    public int lowopening;
    public static int width;
    private Texture bullet;
    private Vector2 bulletpos;
    private Vector2 botbulletpos;


    public Ghost(float x) {
        GhostGap = 120; // the gap between the top and bottom ghost
        lowopening = 90; //
        bullet = new Texture("Bird.png");
        topGhost = new Texture("Bird.png");
        // middletude = new Texture("sipkemiddle.png"); //spelling mistake
        bottomGhost = new Texture("Bird.png");
        rand = new Random();
        width = topGhost.getWidth();
        posBotGhost = new Vector2(x + 120, rand.nextInt(fluct));
        postopGhost = new Vector2(x + 113, posBotGhost.y + bottomGhost.getHeight() + GhostGap - 50); 
        bulletpos = new Vector2(postopGhost);
        botbulletpos = new Vector2(posBotGhost);
    }

    public void repostition(float x) {
        postopGhost.set(x + 75, rand.nextInt(fluct) + 200);
        posBotGhost.set(x + 75, postopGhost.y + GhostGap - bottomGhost.getHeight() - 247);
    }
    public void timer(float dt) {
        int ticker = 0;
        ticker += dt;
        if(ticker > 5) {
            ticker = 0;
            shoot();
        }
    }
    public void shoot(){
        setBulletpos(postopGhost);        
        bulletpos.x = (bulletpos.x + 40);
        bulletpos. y = bulletpos.y;
    }

}

目前无法生成可见的沿X轴移动的子弹，寻求解决建议。

• 修正计时器变量作用域：timer方法内的ticker是局部变量，每次调用都会重置为0，永远触发不了射击逻辑。将ticker改为Ghost类的成员变量，且用float类型存储时间累计：

  private float ticker = 0;
  public void timer(float dt) {
      ticker += dt;
      if(ticker > 5) {
          ticker = 0;
          shoot();
      }
  }
  

• 重构子弹管理逻辑：当前shoot方法每次都会把同一颗子弹拉回幽灵位置再移动，无法生成多颗子弹。改为维护一个子弹列表，每次射击创建新的子弹实例：

  private List<Vector2> bullets = new ArrayList<>();
  
  public void shoot(){
      // 从幽灵位置生成新子弹
      bullets.add(new Vector2(postopGhost.x, postopGhost.y));
  }
  

  同时新增更新方法处理子弹移动与回收：

  public void update(float dt){
      Iterator<Vector2> iterator = bullets.iterator();
      while(iterator.hasNext()){
          Vector2 bullet = iterator.next();
          // 按时间比例移动，保证帧率无关
          bullet.x -= 40 * dt;
          // 移除超出屏幕的子弹，避免内存泄漏
          if(bullet.x < -bullet.getWidth()){
              iterator.remove();
          }
      }
  }
  

• 确保子弹在PlayState中被渲染：在PlayState的render方法里，遍历Ghost的子弹列表绘制每一颗子弹：

  // 假设已有ghost实例和SpriteBatch batch
  for(Vector2 bulletPos : ghost.getBullets()){
      batch.draw(ghost.getBulletTexture(), bulletPos.x, bulletPos.y);
  }
  

  给Ghost类添加对应获取方法：

  public List<Vector2> getBullets(){
      return bullets;
  }
  
  public Texture getBulletTexture(){
      return bullet;
  }
  

• 检查子弹移动方向：如果玩家在幽灵左侧，当前代码bulletpos.x +=40是向右移动，会导致子弹飞离玩家方向，应改为bullet.x -= 速度值。

• 验证纹理加载：确认Bird.png路径正确，可在Ghost构造方法中打印System.out.println(bullet != null)验证纹理是否成功加载。

内容的提问来源于stack exchange，提问作者banabrain