小功能⭐️不用传参，Unity获得鼠标悬浮处的物体、UI！

/// <summary>
        /// 获得当前鼠标悬浮处UI
        /// </summary>
        public static Transform GetOverUI(this Transform trans)
        {
            Transform obj = null;
 
            EventSystem uiEventSystem = EventSystem.current;
            if (uiEventSystem != null)
            {
                PointerEventData uiPointerEventData = new PointerEventData(uiEventSystem);
                uiPointerEventData.position = Input.mousePosition;
 
                List<RaycastResult> uiRaycastResultCache = new List<RaycastResult>();
 
                uiEventSystem.RaycastAll(uiPointerEventData, uiRaycastResultCache);
                if (uiRaycastResultCache.Count > 0)
                {
                    obj = uiRaycastResultCache[0].gameObject.transform;
                }
            }
 
            return obj;
        }

Transform overUI = transform.GetOverUI();

/// <summary>
        /// 获得MainCamera下，当前鼠标下的3D物体
        /// </summary>
        public static Transform GetOverObj(this Transform trans, Camera cam = null)
        {
            Transform obj = null;
            
            cam = cam == null ? Camera.main : cam;
 
            Ray ray = cam.ScreenPointToRay(Input.mousePosition);
            RaycastHit hit;
            if (Physics.Raycast(ray, out hit, cam.farClipPlane))
            {
                // 如果与物体发生碰撞，在Scene视图中绘制射线 
                Debug.DrawLine(ray.origin, hit.point, Color.green);
 
                obj = hit.transform;
            }
 
            return obj;
        }

Transform overObj = transform.GetOverObj();