Unity无法让子弹向正确的方向发射

Question

我试图让我的坦克朝老鼠面对的方向射击。目前坦克可以旋转看着鼠标，但我不知道如何让子弹去正确的方向！

目前顶部的炮塔旋转正确，我不确定那个物体上的旋转是否可以用于方向？

它是 unity 3d 但实际上是 2.5d 角度自上而下。

public class tankScript : MonoBehaviour
{
    public float rotateSpeed = 90;
    public float speed = 5.0f;
    public float fireInterval = 0.5f;
    public float bulletSpeed = 20;
    public Transform spawnPoint;
    public GameObject bulletObject;
    float nextFire;

    Camera cam;
    Collider planecollider;
    RaycastHit hit;
    Ray ray;
    Vector3 mouseDirection;

    void Start()
    {
        nextFire = Time.time + fireInterval;

        cam = GameObject.Find("Main Camera").GetComponent<Camera>();
        planecollider = GameObject.Find("Plane").GetComponent<Collider>();
    }

    void Update()
    {
        var transAmount = speed * Time.deltaTime;
        var rotateAmount = rotateSpeed * Time.deltaTime;

        if (Input.GetKey("w"))
        {
            transform.Translate(0, 0, transAmount);
        }
        if (Input.GetKey("s"))
        {
            transform.Translate(0, 0, -transAmount);
        }
        if (Input.GetKey("a"))
        {
            transform.Rotate(0, -rotateAmount, 0);
        }
        if (Input.GetKey("d"))
        {
            transform.Rotate(0, rotateAmount, 0);
        }
        if (Input.GetButtonDown("Fire1") && Time.time > nextFire)
        {
            nextFire = Time.time + fireInterval;
            fire();
        }
    }

    void fire()
    {
        ray = cam.ScreenPointToRay(Input.mousePosition);
        if (Physics.Raycast(ray, out hit))
        {
            if (hit.collider == planecollider)
            {
                mouseDirection = new Vector3(hit.point.x, 0.25f, hit.point.z);
                float step = bulletSpeed * Time.deltaTime;
                var bullet = Instantiate(bulletObject, spawnPoint.position, spawnPoint.rotation);
                bullet.GetComponent<Rigidbody>().transform.localPosition = Vector3.MoveTowards(transform.localPosition, mouseDirection, step);

            }
        }
    }