From ce866070070dbdcaf46a2ae8d6fa4dfb805162e2 Mon Sep 17 00:00:00 2001
From: nds <natalia.ermolaeva@opencascade.com>
Date: Tue, 26 May 2020 10:39:58 +0300
Subject: [PATCH] 0031579: Visualization - OpenGl_CappingAlgo performance on
 some clipping planes

---
 src/OpenGl/OpenGl_CappingAlgo.cxx | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/src/OpenGl/OpenGl_CappingAlgo.cxx b/src/OpenGl/OpenGl_CappingAlgo.cxx
index eed90116dd..6060fcb050 100755
--- a/src/OpenGl/OpenGl_CappingAlgo.cxx
+++ b/src/OpenGl/OpenGl_CappingAlgo.cxx
@@ -80,6 +80,32 @@ namespace
     theWorkspace->SetAllowFaceCulling (wasCullAllowed);
   }
 
+  Standard_Boolean isGroupClipped (const Handle(Graphic3d_Group)& theGroup, const Handle(OpenGl_Context)& theContext)
+  {
+    const Graphic3d_BndBox3d& aBBox = theGroup->Structure()->CStructure()->BoundingBox();
+    if (!aBBox.IsValid())
+    {
+      return Standard_False;
+    }
+
+    for (OpenGl_ClippingIterator aPlaneIt (theContext->Clipping()); aPlaneIt.More(); aPlaneIt.Next())
+    {
+      const Handle(Graphic3d_ClipPlane)& aPlane = aPlaneIt.Value();
+      if (!aPlane->IsOn())
+      {
+        continue;
+      }
+
+      const Graphic3d_ClipState aBoxState = aPlane->ProbeBox (aBBox);
+      if (aBoxState == Graphic3d_ClipState_Out)
+      {
+        return Standard_True;
+      }
+    }
+    return Standard_False;
+  }
+
+
   //! Render capping for specific structure.
   static void renderCappingForStructure (StencilTestSentry& theStencilSentry,
                                          const Handle(OpenGl_Workspace)& theWorkspace,
@@ -100,6 +126,11 @@ namespace
         continue;
       }
 
+      if (isGroupClipped (aGroupIter.Value(), aContext))
+      {
+        continue;
+      }
+
       // clear stencil only if something has been actually drawn
       theStencilSentry.Init();
 
-- 
2.31.1.windows.1