1 files changed, 44 insertions, 0 deletions

diff --git a/Assets/uGUI-2017.1/UnityEngine.UI/UI/Core/Culling/Clipping.cs b/Assets/uGUI-2017.1/UnityEngine.UI/UI/Core/Culling/Clipping.cs
new file mode 100644
index 0000000..7dd39bf
--- /dev/null
+++ b/Assets/uGUI-2017.1/UnityEngine.UI/UI/Core/Culling/Clipping.cs
@@ -0,0 +1,44 @@
+using System.Collections.Generic;
+
+namespace UnityEngine.UI
+{
+    public static class Clipping
+    {
+        public static Rect FindCullAndClipWorldRect(List<RectMask2D> rectMaskParents, out bool validRect)
+        {
+            if (rectMaskParents.Count == 0)
+            {
+                validRect = false;
+                return new Rect();
+            }
+
+            var compoundRect = rectMaskParents[0].canvasRect;
+            for (var i = 0; i < rectMaskParents.Count; ++i)
+                compoundRect = RectIntersect(compoundRect, rectMaskParents[i].canvasRect);
+
+            var cull = compoundRect.width <= 0 || compoundRect.height <= 0;
+            if (cull)
+            {
+                validRect = false;
+                return new Rect();
+            }
+
+            Vector3 point1 = new Vector3(compoundRect.x, compoundRect.y, 0.0f);
+            Vector3 point2 = new Vector3(compoundRect.x + compoundRect.width, compoundRect.y + compoundRect.height, 0.0f);
+            validRect = true;
+            return new Rect(point1.x, point1.y, point2.x - point1.x, point2.y - point1.y);
+        }
+
+		// ¼ÆËã¾ØÐν»¼¯
+        private static Rect RectIntersect(Rect a, Rect b)
+        {
+            float xMin = Mathf.Max(a.x, b.x);
+            float xMax = Mathf.Min(a.x + a.width, b.x + b.width);
+            float yMin = Mathf.Max(a.y, b.y);
+            float yMax = Mathf.Min(a.y + a.height, b.y + b.height);
+            if (xMax >= xMin && yMax >= yMin)
+                return new Rect(xMin, yMin, xMax - xMin, yMax - yMin);
+            return new Rect(0f, 0f, 0f, 0f);
+        }
+    }
+}