unity:为什么我不能在此脚本中引用" targetVelocity"变量？

最近，我为2D游戏实现了射击系统，但是该系统存在问题.问题在于，当玩家面对左侧时，子弹仍在向右射击.要解决此问题，我需要访问 Vector2 名为 targetVelocity 检查播放器是否正确. targetVelocity 在另一个脚本中定义，称为 PhysicsObject 专门用于播放器物理，并且播放器脚本从中继承（变量为 protected 但我将其更改为 public ）.我只是不知道该如何在我的 Bullet中引用 脚本，而我不想将播放器脚本添加到项目符号中.另外，我已经阅读了与之相似的过去的问题和答案，但是由于情况不同，我还没有找到答案.预先感谢。

This is my Bullet 脚本，我想以某种方式引用 targetVelocity 。

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Bullet : MonoBehaviour
{
    [SerializeField] float speed;
    [SerializeField] float lifeTime;
    public GameObject destroyEffect;
    
    private void Start()
    {
        Invoke("DestroyBullet", lifeTime);
    }
    private void Update()
    {
        transform.Translate(Vector2.right * speed * Time.deltaTime);
    }
    void DestroyBullet()
    {
        Instantiate(destroyEffect, transform.position, Quaternion.identity);
        Destroy(gameObject);
    }
}

Here is the weapon script.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class Weapon : MonoBehaviour
{
    public GameObject bullet;
    public Transform firePoint;
    private float timeBtwShots;
    public float startTimeBtwShots;
    private void Update()
    {
        if (timeBtwShots <= 0)
        {
            if (Input.GetButton("Fire1"))
            {
                Instantiate(bullet, firePoint.position, transform.rotation);
                timeBtwShots = startTimeBtwShots;
            }
        }
        else
        {
            timeBtwShots -= Time.deltaTime;
        }
    }
}

This is the player script.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class NewPlayer : PhysicsObject
{
    [Header("Attributes")]
    [SerializeField] private float jumpPower = 10;
    [SerializeField] private float maxSpeed = 1;
    //Singleton instantation
    private static NewPlayer instance;
    public static NewPlayer Instance
    {
        get
        {
            if (instance == null) instance = GameObject.FindObjectOfType<NewPlayer>();
            return instance;
        }
    }
    // Update is called once per frame
    void Update()
    {
        targetVelocity = new Vector2(Input.GetAxis("Horizontal") * maxSpeed, 0);
        //If the player presses "Jump" and we're grounded, set the velocity to a jump power value
        if (Input.GetButtonDown("Jump") && grounded)
        {
            velocity.y = jumpPower;
        }
        //Flip the player's localScale.x if the move speed is greater than .01 or less than -.01
        if (targetVelocity.x < -.01)
        {
            transform.localScale = new Vector2(-1, 1);
        }
        else if (targetVelocity.x > .01)
        {
            transform.localScale = new Vector2(1, 1);
        }
}
}