From Stephan Huber, "attached you'll find the missing GraphicsHandleCocoa-implementation."

include/osgViewer/api/Cocoa/GraphicsHandleCocoa

@@ -0,0 +1,53 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2009 Robert Osfield 
+ *
+ * This library is open source and may be redistributed and/or modified under  
+ * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or 
+ * (at your option) any later version.  The full license is in LICENSE file
+ * included with this distribution, and on the openscenegraph.org website.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
+ * OpenSceneGraph Public License for more details.
+*/
+
+#ifndef OSGVIEWER_GRAPHICSHANDLECOCOA
+#define OSGVIEWER_GRAPHICSHANDLECOCOA 1
+
+#include <osgViewer/Export>
+
+
+#ifdef __OBJC__
+@class NSOpenGLContext;
+#else
+class NSOpenGLContext;
+#endif
+
+namespace osgViewer
+{
+
+/** Class to encapsulate platform-specific OpenGL context handle variables.
+  * Derived osg::GraphicsContext classes can inherit from this class to
+  * share OpenGL resources.*/
+
+class OSGVIEWER_EXPORT GraphicsHandleCocoa
+{
+    public:
+    
+        GraphicsHandleCocoa():
+            _context(0) {}
+
+        /** Set native AGL graphics context.*/        
+        inline void setNSOpenGLContext(NSOpenGLContext* context) { _context = context; }
+
+        /** Get native AGL graphics context.*/        
+        inline NSOpenGLContext* getNSOpenGLContext() const { return _context; }
+
+    protected:
+        
+        NSOpenGLContext*      _context;
+};
+
+}
+
+#endif

include/osgViewer/api/Cocoa/GraphicsWindowCocoa

@@ -36,18 +36,21 @@ class NSView;
 #endif
 
 #include <osgViewer/GraphicsWindow>
+#include <osgViewer/api/Cocoa/GraphicsHandleCocoa>
 
 // we may not include any cocoa-header here, because this will pollute the name-sapce and tend to compile-errors
 
 namespace osgViewer
 {
 
-class GraphicsWindowCocoa : public osgViewer::GraphicsWindow
+class GraphicsWindowCocoa : public osgViewer::GraphicsWindow, public osgViewer::GraphicsHandleCocoa
 {
     public:
     class Implementation;
 
         GraphicsWindowCocoa(osg::GraphicsContext::Traits* traits):
+            osgViewer::GraphicsWindow(),
+            osgViewer::GraphicsHandleCocoa(),
             _valid(false),
             _initialized(false),
             _realized(false),
@@ -55,8 +58,7 @@ class GraphicsWindowCocoa : public osgViewer::GraphicsWindow
             _checkForEvents(true),
             _ownsWindow(true),
             _currentCursor(RightArrowCursor),
-            _window(NULL),
-            _context(NULL)
+            _window(NULL)
         {
             _traits = traits;
 

include/osgViewer/api/Cocoa/PixelBufferCocoa

@@ -20,23 +20,19 @@
 
 #include <osg/GraphicsContext>
 #include <osgViewer/Export>
-
-
-#ifdef __OBJC__
-@class NSOpenGLContext;
-#else
-class NSOpenGLContext;
-#endif
+#include <osgViewer/api/Cocoa/GraphicsHandleCocoa>
 
 namespace osgViewer
 {
 
-class OSGVIEWER_EXPORT PixelBufferCocoa : public osg::GraphicsContext
+class OSGVIEWER_EXPORT PixelBufferCocoa : public osg::GraphicsContext, public osgViewer::GraphicsHandleCocoa
 {
     public:
         struct Implementation;
 
         PixelBufferCocoa(osg::GraphicsContext::Traits* traits):
+            osg::GraphicsContext(),
+            osgViewer::GraphicsHandleCocoa(),
             _valid(false),
             _initialized(false),
             _realized(false),