更换模型的材质（点击鼠标左右键）

using UnityEngine;
using System.Collections;

public class ChangeMatericals : MonoBehaviour 
{
    public Material IniMaterical;// 替换前材质（原材质）
    public Material ChangeMaterical;//替换后的材质（半透明材质）
    private MeshRenderer mr;
    int index;

    void Start()
    {
        mr = GetComponent<MeshRenderer>();
        mr.sharedMaterial = IniMaterical;
    }
    void Update()
    {
        if (Input.GetMouseButton(0))
        {
            index = 0;
            Change();
        }
        if(Input.GetMouseButton(1))
        {
            index = 1;
            Change();
        }
    }
    public void Change()
    {
        Debug.Log("更换！");
        if (index==0)
        {
            mr.sharedMaterial = null;
            mr.sharedMaterial = ChangeMaterical;
        }
        if (index==1)
        {
            mr.sharedMaterial = null;
            mr.sharedMaterial = IniMaterical;
        }
    }
}