private void HandleShoot()
 {
     if (Input.GetButton(shootBtnName))
     {
         Debug.Log(shootBtnName + "Click!");
         GameObject bulletGO = GameObject.Instantiate(bulletPrefab);
         bulletGO.transform.position = muzzleTrans.position;
         bulletMoveForward = bulletGO.GetComponent<MoveForward>();
         mousePos = Input.mousePosition;
         muzzlePos = Camera.main.WorldToScreenPoint(muzzleTrans.position);
         shootDir = (mousePos - muzzlePos).normalized;
         bulletMoveForward.SetMoveDir(shootDir);
     }
 }