From 760c21c2c474e893c85a26f3b8155bd6dc6165cc Mon Sep 17 00:00:00 2001
From: kgv <kgv@opencascade.com>
Date: Fri, 20 Feb 2015 20:01:46 +0300
Subject: [PATCH] 0025851: Visualization, TKOpenGl - do not use FBO cache when
 GLSL is unavailable

---
 src/OpenGl/OpenGl_Workspace.cxx | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/OpenGl/OpenGl_Workspace.cxx b/src/OpenGl/OpenGl_Workspace.cxx
index 80e6ff1366..d9f8cca982 100644
--- a/src/OpenGl/OpenGl_Workspace.cxx
+++ b/src/OpenGl/OpenGl_Workspace.cxx
@@ -674,7 +674,12 @@ void OpenGl_Workspace::Redraw (const Graphic3d_CView& theCView,
   if (myResultFBO->GetVPSizeX() != aSizeX
    || myResultFBO->GetVPSizeY() != aSizeY)
   {
-    myResultFBO->Init (aGlCtx, aSizeX, aSizeY);
+    // prepare FBOs containing main scene
+    // for further blitting and rendering immediate presentations on top
+    if (aGlCtx->core20fwd != NULL)
+    {
+      myResultFBO->Init (aGlCtx, aSizeX, aSizeY);
+    }
   }
   if (myResultFBO->IsValid())
   {