public Bomb(Stage stage, int heading, int x, int y) {
        super(stage);
        this.x = x;
        this.y = y;
        String sprite ="";
        switch (heading) {
          case UP_LEFT : vx = -BOMB_SPEED; vy = -BOMB_SPEED; sprite="bombUL.gif";break;
          case UP : vx = 0; vy = -BOMB_SPEED; sprite="bombU.gif";break;
          case UP_RIGHT: vx = BOMB_SPEED; vy = -BOMB_SPEED; sprite="bombUR.gif";break;
          case LEFT : vx = -BOMB_SPEED; vy = 0; sprite = "bombL.gif";break;
          case RIGHT : vx = BOMB_SPEED; vy = 0; sprite = "bombR.gif";break;
          case DOWN_LEFT : vx = -BOMB_SPEED; vy = BOMB_SPEED; sprite="bombDL.gif";break;
          case DOWN : vx = 0; vy = BOMB_SPEED; sprite = "bombD.gif";break;
          case DOWN_RIGHT : vx = BOMB_SPEED; vy = BOMB_SPEED; sprite = "bombDR.gif";break;
        }   
        setSpriteNames( new String[] {sprite});
      }