鼠标悬停在游戏对象上方时，不会改变游戏对象的材质

        public Material startColor;
        public Material mouseOverColor;
        Renderer rend;

        void OnMouseOver()
        {
            rend.sharedMaterial = mouseOverColor;
        }

        void OnMouseExit()
        {
            rend.sharedMaterial = startColor;
        }

        // Start is called before the first frame update
        void Start()
        {
            rend = GetComponent<Renderer>();
            rend.enabled = true;
            rend.sharedMaterial = startColor;
        }