From Marius Heise, "here is a patch that implements Win32 HW-synced swapping using wglJoinSwapGroupNV, wglBindSwapBarrierNV and the existing traits. It was tested with multiple ATI FirePro S400 cards.

I also fixed the vsync implementation introduced with rev.11357 that was crashing with the Windows Error #170. So I removed your temporary /* */ around the vsync condition..."

include/osgViewer/api/Win32/GraphicsWindowWin32

@@ -90,6 +90,9 @@ class OSGVIEWER_EXPORT GraphicsWindowWin32 : public osgViewer::GraphicsWindow, p
         /** Set sync-to-vblank. */
         virtual void setSyncToVBlank(bool on);
 
+        /** Set swap group. */
+        virtual void setSwapGroup(bool on, GLuint group, GLuint barrier);
+
         /** Handle a native (Win32) windowing event as received from the system */
         virtual LRESULT handleNativeWindowingEvent( HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam );