void Update()
    {
        if(Input.GetMouseButtonDown(0))
        {
            GetComponent<Renderer>().material.color = new Color(Random.value, Random.value, Random.value, 1.0f);
        }
    }

        public override void Raycast(PointerEventData eventData, List<RaycastResult> resultAppendList)
        {
            if (canvas == null)
                return;

            // Convert to view space
            Vector2 pos;
            if (eventCamera == null)
                pos = new Vector2(eventData.position.x / Screen.width, eventData.position.y / Screen.height);
            else
                pos = eventCamera.ScreenToViewportPoint(eventData.position);

            // If it's outside the camera's viewport, do nothing
            if (pos.x < 0f || pos.x > 1f || pos.y < 0f || pos.y > 1f)
                return;

            float hitDistance = float.MaxValue;

            Ray ray = new Ray();

            if (eventCamera != null)
                ray = eventCamera.ScreenPointToRay(eventData.position);

            if (canvas.renderMode != RenderMode.ScreenSpaceOverlay && blockingObjects != BlockingObjects.None)
            {
                float dist = eventCamera.farClipPlane - eventCamera.nearClipPlane;

                if (blockingObjects == BlockingObjects.ThreeD || blockingObjects == BlockingObjects.All)
                {
                    RaycastHit hit;
                    if (Physics.Raycast(ray, out hit, dist, m_BlockingMask))
                    {
                        hitDistance = hit.distance;
                    }
                }

                if (blockingObjects == BlockingObjects.TwoD || blockingObjects == BlockingObjects.All)
                {
                    RaycastHit2D hit = Physics2D.Raycast(ray.origin, ray.direction, dist, m_BlockingMask);

                    if (hit.collider != null)
                    {
                        hitDistance = hit.fraction * dist;
                    }
                }
            }

            m_RaycastResults.Clear();
            Raycast(canvas, eventCamera, eventData.position, m_RaycastResults);

            for (var index = 0; index < m_RaycastResults.Count; index++)
            {
                var go = m_RaycastResults[index].gameObject;
                bool appendGraphic = true;

                if (ignoreReversedGraphics)
                {
                    if (eventCamera == null)
                    {
                        // If we dont have a camera we know that we should always be facing forward
                        var dir = go.transform.rotation * Vector3.forward;
                        appendGraphic = Vector3.Dot(Vector3.forward, dir) > 0;
                    }
                    else
                    {
                        // If we have a camera compare the direction against the cameras forward.
                        var cameraFoward = eventCamera.transform.rotation * Vector3.forward;
                        var dir = go.transform.rotation * Vector3.forward;
                        appendGraphic = Vector3.Dot(cameraFoward, dir) > 0;
                    }
                }

                if (appendGraphic)
                {
                    float distance = 0;

                    if (eventCamera == null || canvas.renderMode == RenderMode.ScreenSpaceOverlay)
                        distance = 0;
                    else
                    {
                        // http:///a06-_intersect-2.html
                        distance = (Vector3.Dot(go.transform.forward, go.transform.position - ray.origin) / Vector3.Dot(go.transform.forward, ray.direction));

                        // Check to see if the go is behind the camera.
                        if (distance < 0)
                            continue;
                    }

                    if (distance >= hitDistance)
                        continue;

                    var castResult = new RaycastResult
                    {
                        gameObject = go,
                        module = this,
                        distance = distance,
                        index = resultAppendList.Count,
                        depth = m_RaycastResults[index].depth,
                        sortingLayer =  canvas.sortingLayerID,
                        sortingOrder = canvas.sortingOrder
                    };
                    resultAppendList.Add(castResult);
                }
            }
        }

        protected override void OnEnable()
        {
            base.OnEnable();
            CacheCanvas();
            GraphicRegistry.RegisterGraphicForCanvas(canvas, this);

#if UNITY_EDITOR
            GraphicRebuildTracker.TrackGraphic(this);
#endif
            if (s_WhiteTexture == null)
                s_WhiteTexture = Texture2D.whiteTexture;

            SetAllDirty();

            SendGraphicEnabledDisabled();
        }

        public static void RegisterGraphicForCanvas(Canvas c, Graphic graphic)
        {
            if (c == null)
                return;

            IndexedSet<Graphic> graphics;
            instance.m_Graphics.TryGetValue(c, out graphics);

            if (graphics != null)
            {
                graphics.Add(graphic);
                return;
            }

            graphics = new IndexedSet<Graphic>();
            graphics.Add(graphic);
            instance.m_Graphics.Add(c, graphics);
        }

    bool CheckGuiRaycastObjects()
    {
        PointerEventData eventData = new PointerEventData(Main.Instance.eventSystem);
        eventData.pressPosition = Input.mousePosition;
        eventData.position = Input.mousePosition;

        List<RaycastResult> list = new List<RaycastResult>();
        Main.Instance.graphicRaycaster.Raycast(eventData, list);
        //Debug.Log(list.Count);
        return list.Count > 0;
    }

    void Update () 
    {
        if (CheckGuiRaycastObjects()) return;
        //Debug.Log(EventSystem.current.gameObject.name);
        if (Input.GetMouseButtonDown(0))
        {
            Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
            RaycastHit hit;

            if (Physics.Raycast(ray, out hit))
            {
                //do some thing
            }
        }
    }