Unity 鼠标跟随点击位置

using UnityEngine;
using UnityEngine.AI;

public class MeshlinksDemo : MonoBehaviour {

    NavMeshAgent mr;   //声明变量
	// Use this for initialization
	void Start () {
        //获取到自身的NavMeshAgent组件
        mr = GetComponent<NavMeshAgent>();
	}
	
	// Update is called once per frame
	void Update () {
       
        if (Input.GetMouseButtonDown(0))
        {
            //获取鼠标点击的点，
            Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
            RaycastHit rayhit;  //声明RacastHit类型
            if (Physics.Raycast(ray, out rayhit))  
            {
                if (rayhit.transform.name == "Plane") //判断是不是点击地面
                {
                    //鼠标点击的点赋值给目标点
                    mr.SetDestination(rayhit.point);
                }
            }
        }

	}
}