我把tf理解为一个需要移动的角色。
根据OnMouseDown函数，
当用户在碰撞器上按下鼠标按钮时，将调用OnMouseDown。
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你需要一个背景，脚本可能会附加到它。从背景中获取鼠标位置。然后将位置设置为tf（字符）。2D游戏的z位置应该总是0。当然，你可以根据需要改变背景的大小。
图像和脚本可以更好地解释。

下面是GoToMouse.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class GoToMouse : MonoBehaviour
{
    public Transform tf;
    private bool Selected = false;

    // Start is called before the first frame update
    void Start()
    {
        // the tf is drag and drop from unity
        //tf = GetComponent<Transform>();
    }

    private void OnMouseDown()
    {
        if (Selected == false)
        {
            Selected = true;
        }
        if (Selected == true)
        {
            Vector3 mousePos = Camera.main.ScreenToWorldPoint(Input.mousePosition);
            tf.position = new Vector3(mousePos.x,mousePos.y,tf.position.z); // notice the tf.position.z
        }
    }

    private void OnMouseUp()
    {
        if (Selected == true)
        {
            Selected = false;
        }
    }

}

最后我终于弄明白了，我不知道我做错了什么，但这个新剧本看起来很好用。

using System.Collections;
using System.Collections.Generic;
using System.Runtime.CompilerServices;
using UnityEngine;

public class MoveTowards : MonoBehaviour
{
    private Rigidbody2D rb;
    public float force = 1f;
    private bool selected = false;

    public void Awake()
    {
        //Get rigidbody from the gameobject this script is attatched to
        rb = GetComponent<Rigidbody2D>();
    }

    public void OnMouseDown()
    {
        //become selected when clicked
        selected = true;
    }

    public void OnMouseUp()
    {
        //become deselected when you let go of left click
        selected = false;
    }

    void Update()
    {
        if (selected == true)
        {
            //move towards mouse if selected
            Vector3 mousePos = Camera.main.ScreenToWorldPoint(Input.mousePosition);
            Vector3 dir = (mousePos - transform.position);
            dir.z = 0.0f;
            Vector3 dirNormalized = dir.normalized;
            Vector2 relativePos = mousePos - gameObject.transform.position;
            rb.AddForce(relativePos * force);
            
        }

    }

}