/**
         *  Static function to handle the GUI and User input related to the cascade slider.
         *
         *  @param  normalizedCascadePartition      The array of partition sizes in the range 0.0f - 1.0f; expects ONE entry if cascades = 2, and THREE if cascades=4
         *                                          The last entry will be automatically determined by summing up the array, and doing 1.0f - sum
         */
        public static void HandleCascadeSliderGUI(ref float[] normalizedCascadePartitions)
        {
            GUILayout.Label("Cascade splits");

            // get the inspector width since we need it while drawing the partition rects.
            // Only way currently is to reserve the block in the layout using GetRect(), and then immediately drawing the empty box
            // to match the call to GetRect.
            // From this point on, we move to non-layout based code.
            var sliderRect = GUILayoutUtility.GetRect(GUIContent.none
                                                      , s_CascadeSliderBG
                                                      , GUILayout.Height(kSliderbarTopMargin + kSliderbarHeight + kSliderbarBottomMargin)
                                                      , GUILayout.ExpandWidth(true));

            GUI.Box(sliderRect, GUIContent.none);

            float currentX            = sliderRect.x;
            float cascadeBoxStartY    = sliderRect.y + kSliderbarTopMargin;
            float cascadeSliderWidth  = sliderRect.width - (normalizedCascadePartitions.Length * kPartitionHandleWidth);
            Color origTextColor       = GUI.color;
            Color origBackgroundColor = GUI.backgroundColor;
            int   colorIndex          = -1;

            // setup the array locally with the last partition
            float[] adjustedCascadePartitions = new float[normalizedCascadePartitions.Length + 1];
            Array.Copy(normalizedCascadePartitions, adjustedCascadePartitions, normalizedCascadePartitions.Length);
            adjustedCascadePartitions[adjustedCascadePartitions.Length - 1] = 1.0f - normalizedCascadePartitions.Sum();


            // check for user input on any of the partition handles
            // this mechanism gets the current event in the queue... make sure that the mouse is over our control before consuming the event
            int   sliderControlId         = GUIUtility.GetControlID(s_CascadeSliderId, FocusType.Passive);
            Event currentEvent            = Event.current;
            int   hotPartitionHandleIndex = -1; // the index of any partition handle that we are hovering over or dragging

            // draw each cascade partition
            for (int i = 0; i < adjustedCascadePartitions.Length; ++i)
            {
                float currentPartition = adjustedCascadePartitions[i];

                colorIndex          = (colorIndex + 1) % kCascadeColors.Length;
                GUI.backgroundColor = kCascadeColors[colorIndex];
                float boxLength = (cascadeSliderWidth * currentPartition);

                // main cascade box
                Rect partitionRect = new Rect(currentX, cascadeBoxStartY, boxLength, kSliderbarHeight);
                GUI.Box(partitionRect, GUIContent.none, s_CascadeSliderBG);
                currentX += boxLength;

                // cascade box percentage text
                GUI.color = Color.white;
                Rect textRect    = partitionRect;
                var  cascadeText = UnityString.Format("{0}\n{1:F1}%", i, currentPartition * 100.0f);

                GUI.Label(textRect, GUIContent.Temp(cascadeText, cascadeText), s_TextCenteredStyle);

                // no need to draw the partition handle for last box
                if (i == adjustedCascadePartitions.Length - 1)
                {
                    break;
                }

                // partition handle
                GUI.backgroundColor = Color.black;
                Rect handleRect = partitionRect;
                handleRect.x     = currentX;
                handleRect.width = kPartitionHandleWidth;
                GUI.Box(handleRect, GUIContent.none, s_CascadeSliderBG);
                // we want a thin handle visually (since wide black bar looks bad), but a slightly larger
                // hit area for easier manipulation
                Rect handleHitRect = handleRect;
                handleHitRect.xMin -= kPartitionHandleExtraHitAreaWidth;
                handleHitRect.xMax += kPartitionHandleExtraHitAreaWidth;
                if (handleHitRect.Contains(currentEvent.mousePosition))
                {
                    hotPartitionHandleIndex = i;
                }

                // add regions to slider where the cursor changes to Resize-Horizontal
                if (s_DragCache == null)
                {
                    EditorGUIUtility.AddCursorRect(handleHitRect, MouseCursor.ResizeHorizontal, sliderControlId);
                }

                currentX += kPartitionHandleWidth;
            }

            GUI.color           = origTextColor;
            GUI.backgroundColor = origBackgroundColor;

            EventType eventType = currentEvent.GetTypeForControl(sliderControlId);

            switch (eventType)
            {
            case EventType.MouseDown:
                if (hotPartitionHandleIndex >= 0)
                {
                    s_DragCache = new DragCache(hotPartitionHandleIndex, normalizedCascadePartitions[hotPartitionHandleIndex], currentEvent.mousePosition);
                    if (GUIUtility.hotControl == 0)
                    {
                        GUIUtility.hotControl = sliderControlId;
                    }
                    currentEvent.Use();

                    // Switch active scene view into shadow cascades visualization mode, once we start
                    // tweaking cascade splits.
                    if (s_RestoreSceneView == null)
                    {
                        s_RestoreSceneView = SceneView.lastActiveSceneView;
                        if (s_RestoreSceneView != null)
                        {
                            s_OldSceneDrawMode            = s_RestoreSceneView.cameraMode;
                            s_OldSceneLightingMode        = s_RestoreSceneView.sceneLighting;
                            s_RestoreSceneView.cameraMode = SceneView.GetBuiltinCameraMode(DrawCameraMode.ShadowCascades);
                        }
                    }
                }
                break;

            case EventType.MouseUp:
                // mouseUp event anywhere should release the hotcontrol (if it belongs to us), drags (if any)
                if (GUIUtility.hotControl == sliderControlId)
                {
                    GUIUtility.hotControl = 0;
                    currentEvent.Use();
                }
                s_DragCache = null;

                // Restore previous scene view drawing mode once we stop tweaking cascade splits.
                if (s_RestoreSceneView != null)
                {
                    s_RestoreSceneView.cameraMode    = s_OldSceneDrawMode;
                    s_RestoreSceneView.sceneLighting = s_OldSceneLightingMode;
                    s_RestoreSceneView = null;
                }
                break;

            case EventType.MouseDrag:
                if (GUIUtility.hotControl != sliderControlId)
                {
                    break;
                }

                // convert the mouse movement to normalized cascade width. Make sure that we are safe to apply the delta before using it.
                float delta = (currentEvent.mousePosition - s_DragCache.m_LastCachedMousePosition).x / cascadeSliderWidth;
                bool  isLeftPartitionHappy  = ((adjustedCascadePartitions[s_DragCache.m_ActivePartition] + delta) > 0.0f);
                bool  isRightPartitionHappy = ((adjustedCascadePartitions[s_DragCache.m_ActivePartition + 1] - delta) > 0.0f);
                if (isLeftPartitionHappy && isRightPartitionHappy)
                {
                    s_DragCache.m_NormalizedPartitionSize += delta;
                    normalizedCascadePartitions[s_DragCache.m_ActivePartition] = s_DragCache.m_NormalizedPartitionSize;
                    if (s_DragCache.m_ActivePartition < normalizedCascadePartitions.Length - 1)
                    {
                        normalizedCascadePartitions[s_DragCache.m_ActivePartition + 1] -= delta;
                    }
                    GUI.changed = true;
                }
                s_DragCache.m_LastCachedMousePosition = currentEvent.mousePosition;
                currentEvent.Use();
                break;
            }
        }
        public static void HandleCascadeSliderGUI(ref float[] normalizedCascadePartitions)
        {
            GUILayout.Label("Cascade splits", new GUILayoutOption[0]);
            Rect rect = GUILayoutUtility.GetRect(GUIContent.none, ShadowCascadeSplitGUI.s_CascadeSliderBG, new GUILayoutOption[]
            {
                GUILayout.Height(28f),
                GUILayout.ExpandWidth(true)
            });

            GUI.Box(rect, GUIContent.none);
            float num             = rect.x;
            float y               = rect.y + 2f;
            float num2            = rect.width - (float)(normalizedCascadePartitions.Length * 2);
            Color color           = GUI.color;
            Color backgroundColor = GUI.backgroundColor;
            int   num3            = -1;

            float[] array = new float[normalizedCascadePartitions.Length + 1];
            Array.Copy(normalizedCascadePartitions, array, normalizedCascadePartitions.Length);
            array[array.Length - 1] = 1f - normalizedCascadePartitions.Sum();
            int   controlID = GUIUtility.GetControlID(ShadowCascadeSplitGUI.s_CascadeSliderId, FocusType.Passive);
            Event current   = Event.current;
            int   num4      = -1;

            for (int i = 0; i < array.Length; i++)
            {
                float num5 = array[i];
                num3 = (num3 + 1) % ShadowCascadeSplitGUI.kCascadeColors.Length;
                GUI.backgroundColor = ShadowCascadeSplitGUI.kCascadeColors[num3];
                float num6  = num2 * num5;
                Rect  rect2 = new Rect(num, y, num6, 24f);
                GUI.Box(rect2, GUIContent.none, ShadowCascadeSplitGUI.s_CascadeSliderBG);
                num      += num6;
                GUI.color = Color.white;
                Rect   position = rect2;
                string text     = string.Format("{0}\n{1:F1}%", i, num5 * 100f);
                GUI.Label(position, GUIContent.Temp(text, text), ShadowCascadeSplitGUI.s_TextCenteredStyle);
                if (i == array.Length - 1)
                {
                    break;
                }
                GUI.backgroundColor = Color.black;
                Rect rect3 = rect2;
                rect3.x     = num;
                rect3.width = 2f;
                GUI.Box(rect3, GUIContent.none, ShadowCascadeSplitGUI.s_CascadeSliderBG);
                Rect position2 = rect3;
                position2.xMin -= 2f;
                position2.xMax += 2f;
                if (position2.Contains(current.mousePosition))
                {
                    num4 = i;
                }
                if (ShadowCascadeSplitGUI.s_DragCache == null)
                {
                    EditorGUIUtility.AddCursorRect(position2, MouseCursor.ResizeHorizontal, controlID);
                }
                num += 2f;
            }
            GUI.color           = color;
            GUI.backgroundColor = backgroundColor;
            EventType typeForControl = current.GetTypeForControl(controlID);

            if (typeForControl != EventType.MouseDown)
            {
                if (typeForControl != EventType.MouseUp)
                {
                    if (typeForControl == EventType.MouseDrag)
                    {
                        if (GUIUtility.hotControl == controlID)
                        {
                            float num7  = (current.mousePosition - ShadowCascadeSplitGUI.s_DragCache.m_LastCachedMousePosition).x / num2;
                            bool  flag  = array[ShadowCascadeSplitGUI.s_DragCache.m_ActivePartition] + num7 > 0f;
                            bool  flag2 = array[ShadowCascadeSplitGUI.s_DragCache.m_ActivePartition + 1] - num7 > 0f;
                            if (flag && flag2)
                            {
                                ShadowCascadeSplitGUI.s_DragCache.m_NormalizedPartitionSize += num7;
                                normalizedCascadePartitions[ShadowCascadeSplitGUI.s_DragCache.m_ActivePartition] = ShadowCascadeSplitGUI.s_DragCache.m_NormalizedPartitionSize;
                                if (ShadowCascadeSplitGUI.s_DragCache.m_ActivePartition < normalizedCascadePartitions.Length - 1)
                                {
                                    normalizedCascadePartitions[ShadowCascadeSplitGUI.s_DragCache.m_ActivePartition + 1] -= num7;
                                }
                                GUI.changed = true;
                            }
                            ShadowCascadeSplitGUI.s_DragCache.m_LastCachedMousePosition = current.mousePosition;
                            current.Use();
                        }
                    }
                }
                else
                {
                    if (GUIUtility.hotControl == controlID)
                    {
                        GUIUtility.hotControl = 0;
                        current.Use();
                    }
                    ShadowCascadeSplitGUI.s_DragCache = null;
                    if (ShadowCascadeSplitGUI.s_RestoreSceneView != null)
                    {
                        ShadowCascadeSplitGUI.s_RestoreSceneView.cameraMode      = ShadowCascadeSplitGUI.s_OldSceneDrawMode;
                        ShadowCascadeSplitGUI.s_RestoreSceneView.m_SceneLighting = ShadowCascadeSplitGUI.s_OldSceneLightingMode;
                        ShadowCascadeSplitGUI.s_RestoreSceneView = null;
                    }
                }
            }
            else if (num4 >= 0)
            {
                ShadowCascadeSplitGUI.s_DragCache = new ShadowCascadeSplitGUI.DragCache(num4, normalizedCascadePartitions[num4], current.mousePosition);
                if (GUIUtility.hotControl == 0)
                {
                    GUIUtility.hotControl = controlID;
                }
                current.Use();
                if (ShadowCascadeSplitGUI.s_RestoreSceneView == null)
                {
                    ShadowCascadeSplitGUI.s_RestoreSceneView = SceneView.lastActiveSceneView;
                    if (ShadowCascadeSplitGUI.s_RestoreSceneView != null)
                    {
                        ShadowCascadeSplitGUI.s_OldSceneDrawMode            = ShadowCascadeSplitGUI.s_RestoreSceneView.cameraMode;
                        ShadowCascadeSplitGUI.s_OldSceneLightingMode        = ShadowCascadeSplitGUI.s_RestoreSceneView.m_SceneLighting;
                        ShadowCascadeSplitGUI.s_RestoreSceneView.cameraMode = SceneView.GetBuiltinCameraMode(DrawCameraMode.ShadowCascades);
                    }
                }
            }
        }