Unity 物体位置跟随鼠标位置移动

鼠标点击后，获取鼠标点击到的屏幕位置，
通过射线点击获取到3D空间中射线点击到的位置pos，
Ray ray = Camera.main.ScreenPointToRay(mousePos);
实时的将物体A位置移动到点pos。

注意：保证场景内有带碰撞的背景

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

//物体位置跟随鼠标移动
public class MovetoMousePos : MonoBehavIoUr {

    public Transform obj;
    public Vector3 targetPos;
    public float speed;

	// Use this for initialization
	void Start () {
        //obj = this.transform;
        targetPos = obj.position;

	}

    void Moveto()
    {
        if (Input.GetMouseButtonDown(0))
        {
            //获取鼠标位置
            Vector3 mousePos = Input.mousePosition;
            //将屏幕位置转为射线
            Ray ray = Camera.main.ScreenPointToRay(mousePos);
            //用来记录射线碰撞记录
            RaycastHit hitInfo;
            //产生射线
            bool isCast = Physics.Raycast(ray, out hitInfo);
            if (isCast)
            {
                //记录碰撞位置
                targetPos = hitInfo.point;
            }
        }

        //朝目标方向移动位置
        Vector3 pos = Vector3.Movetowards(obj.position,targetPos,speed*Time.deltaTime);
        //更新当前位置
        obj.position = pos;
    }
	// Update is called once per frame
	void Update ()
    {
        Moveto();	
	}
}