0024819: TKOpenGl - extend the ray-tracing core by visualization of lines, text and point sprites

OpenGl_GraphicDriver::Redraw() - do not recompute structures more than required
OpenGl_Workspace::Raytrace() - bind proper FBO before clearing it
Visual3d_View::Redraw() - perform automatic 2nd redraw on device lost

src/OpenGl/OpenGl_View.hxx

@@ -221,6 +221,7 @@ protected:
   void RedrawLayer2d (const Handle(OpenGl_PrinterContext)& thePrintContext,
                       const Graphic3d_CView&               theCView,
                       const Aspect_CLayer2d&               theCLayer);
+  void RedrawTrihedron (const Handle(OpenGl_Workspace) &theWorkspace);
 
   //! Redraw contents of model scene: clipping planes,
   //! lights, structures. The peculiar properties of "scene" is that
@@ -296,6 +297,8 @@ public:
   DEFINE_STANDARD_ALLOC
   DEFINE_STANDARD_RTTI(OpenGl_View) // Type definition
 
+  friend class OpenGl_Workspace;
+
 };
 
 #endif // _OpenGl_View_Header