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

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 );