From 37eb4787919d0babc6a322ebd4e887555c54a618 Mon Sep 17 00:00:00 2001
From: osa <osa@opencascade.com>
Date: Fri, 12 Oct 2012 13:37:55 +0400
Subject: [PATCH] 0023428: Extend OpenGl_Context to use Geometry Shaders
 extension Additional corrective integration

---
 src/OpenGl/OpenGl_Context.cxx | 15 +++++++++++++++
 src/OpenGl/OpenGl_Context.hxx |  2 ++
 2 files changed, 17 insertions(+)

diff --git a/src/OpenGl/OpenGl_Context.cxx b/src/OpenGl/OpenGl_Context.cxx
index 00f8c2f0f9..74747aa076 100644
--- a/src/OpenGl/OpenGl_Context.cxx
+++ b/src/OpenGl/OpenGl_Context.cxx
@@ -28,6 +28,7 @@
 #include <OpenGl_ArbTBO.hxx>
 #include <OpenGl_ArbIns.hxx>
 #include <OpenGl_ExtFBO.hxx>
+#include <OpenGl_ExtGS.hxx>
 #include <OpenGl_GlCore20.hxx>
 
 #include <Standard_ProgramError.hxx>
@@ -77,6 +78,7 @@ OpenGl_Context::OpenGl_Context()
   arbTBO (NULL),
   arbIns (NULL),
   extFBO (NULL),
+  extGS  (NULL),
   atiMem (Standard_False),
   nvxMem (Standard_False),
   mySharedResources (new OpenGl_ResourcesMap()),
@@ -125,6 +127,7 @@ OpenGl_Context::~OpenGl_Context()
   delete myGlCore20;
   delete arbVBO;
   delete extFBO;
+  delete extGS;
 }
 
 // =======================================================================
@@ -530,6 +533,18 @@ void OpenGl_Context::init()
     }
   }
 
+  // initialize GS extension (EXT)
+  if (CheckExtension ("GL_EXT_geometry_shader4"))
+  {
+    extGS = new OpenGl_ExtGS();
+    memset (extGS, 0, sizeof(OpenGl_ExtGS)); // nullify whole structure
+    if (!FindProcShort (extGS, glProgramParameteriEXT))
+    {
+      delete extGS;
+      extGS = NULL;
+    }
+  }
+
   myGlCore20 = new OpenGl_GlCore20();
   memset (myGlCore20, 0, sizeof(OpenGl_GlCore20)); // nullify whole structure
 
diff --git a/src/OpenGl/OpenGl_Context.hxx b/src/OpenGl/OpenGl_Context.hxx
index 1d30704018..0fd25a32b0 100644
--- a/src/OpenGl/OpenGl_Context.hxx
+++ b/src/OpenGl/OpenGl_Context.hxx
@@ -44,6 +44,7 @@ struct OpenGl_ArbVBO;
 struct OpenGl_ArbTBO;
 struct OpenGl_ArbIns;
 struct OpenGl_ExtFBO;
+struct OpenGl_ExtGS;
 
 //! This class generalize access to the GL context and available extensions.
 //!
@@ -234,6 +235,7 @@ public: // extensions
   OpenGl_ArbTBO*   arbTBO; //!< GL_ARB_texture_buffer_object
   OpenGl_ArbIns*   arbIns; //!< GL_ARB_draw_instanced
   OpenGl_ExtFBO*   extFBO; //!< GL_EXT_framebuffer_object
+  OpenGl_ExtGS*    extGS;  //!< GL_EXT_geometry_shader4
   Standard_Boolean atiMem; //!< GL_ATI_meminfo
   Standard_Boolean nvxMem; //!< GL_NVX_gpu_memory_info
 
-- 
2.20.1