From Ulrich Hertlien with little bits from Robert Osfield and Chris Hanson, added provisionl support for controlling sync to vblank.

include/osgViewer/GraphicsWindow

@@ -134,6 +134,14 @@ class OSGVIEWER_EXPORT GraphicsWindow : public osg::GraphicsContext, public osgG
         /** Create a new mouse cursor from the usual bitmap data.*/
         //virtual MouseCursor createCursor(const char *data, const char *mask, unsigned w, unsigned h, unsigned hotx, unsigned hoty) { osg::notify(osg::NOTICE)<<"GraphicsWindow::createCursor(..) not implemented."<<std::endl; }
 
+        /** Set sync-to-vblank. */
+        virtual void setSyncToVBlank(bool on)
+        {
+            osg::notify(osg::NOTICE) << "GraphicsWindow::setSyncToVBlank(" << on << ") not implemented." << std::endl;
+        }
+
+        bool getSyncToVBlank() const { return _traits.valid() ? _traits->vsync : true; }
+
     public:
 
         /** Return whether a valid and usable GraphicsContext has been created.*/

include/osgViewer/ViewerEventHandlers

@@ -68,7 +68,9 @@ class OSGVIEWER_EXPORT HelpHandler : public osgGA::GUIEventHandler
 
 };
 
-/** Event handler for adding on screen stats reporting to Viewers.*/
+/**
+ * Event handler for adding on screen stats reporting to Viewers.
+ */
 class OSGVIEWER_EXPORT StatsHandler : public osgGA::GUIEventHandler
 {
     public:
@@ -91,6 +93,9 @@ class OSGVIEWER_EXPORT StatsHandler : public osgGA::GUIEventHandler
         void setKeyEventPrintsOutStats(int key) { _keyEventPrintsOutStats = key; }
         int getKeyEventPrintsOutStats() const { return _keyEventPrintsOutStats; }
 
+        void setKeyEventToggleVSync(int key) { _keyEventToggleVSync = key; }
+        int getKeyEventToggleVSync() const { return _keyEventToggleVSync; }
+
         double getBlockMultiplier() const { return _blockMultiplier; }
 
         void reset();
@@ -123,6 +128,7 @@ class OSGVIEWER_EXPORT StatsHandler : public osgGA::GUIEventHandler
 
         int                                 _keyEventTogglesOnScreenStats;
         int                                 _keyEventPrintsOutStats;
+        int                                 _keyEventToggleVSync;
 
         int                                 _statsType;
 

include/osgViewer/api/Carbon/GraphicsWindowCarbon

@@ -36,7 +36,8 @@ class GraphicsWindowCarbon : public osgViewer::GraphicsWindow, public osgViewer:
             _initialized(false),
             _realized(false),
             _ownsWindow(true),
-            _currentCursor(RightArrowCursor)
+            _currentCursor(RightArrowCursor),
+            _currentVSync(true)
         {
             _traits = traits;
 
@@ -108,7 +109,10 @@ class GraphicsWindowCarbon : public osgViewer::GraphicsWindow, public osgViewer:
         virtual void setWindowName (const std::string & name);
         virtual void useCursor(bool cursorOn);
         virtual void setCursor(MouseCursor mouseCursor);
-        
+
+        /** Set sync-to-vblank. */
+        virtual void setSyncToVBlank(bool on);
+
         WindowRef getNativeWindowRef() { return _window; }
         
         bool handleMouseEvent(EventRef theEvent);
@@ -168,6 +172,7 @@ class GraphicsWindowCarbon : public osgViewer::GraphicsWindow, public osgViewer:
         bool            _closeRequested;
         UInt32          _lastModifierKeys;
         MouseCursor     _currentCursor;
+        bool            _currentVSync;
 };
 
 }

include/osgViewer/api/Win32/GraphicsWindowWin32

@@ -86,7 +86,10 @@ class OSGVIEWER_EXPORT GraphicsWindowWin32 : public osgViewer::GraphicsWindow, p
         
         /** Set mouse cursor to a specific shape.*/
         virtual void setCursor(MouseCursor cursor);
-        
+
+        /** Set sync-to-vblank. */
+        virtual void setSyncToVBlank(bool on);
+
         /** Handle a native (Win32) windowing event as received from the system */
         virtual LRESULT handleNativeWindowingEvent( HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam );