Index: /OpenSceneGraph/trunk/include/osg/StateAttributeCallback
===================================================================
--- /OpenSceneGraph/trunk/include/osg/StateAttributeCallback (revision 10672)
+++ /OpenSceneGraph/trunk/include/osg/StateAttributeCallback (revision 10672)
@@ -0,0 +1,39 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 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 OSG_STATEATTRIBUTECALLBACK
+#define OSG_STATEATTRIBUTECALLBACK 1
+
+#include <osg/Export>
+#include <osg/Object>
+
+namespace osg {
+
+class StateAttribute;
+class NodeVisitor;
+
+class OSG_EXPORT StateAttributeCallback : public virtual osg::Object
+{
+    public:
+        StateAttributeCallback() {}
+
+        StateAttributeCallback(const StateAttributeCallback&,const CopyOp&) {}
+
+        META_Object(osg,StateAttributeCallback);
+
+        /** do customized update code.*/
+        virtual void operator () (StateAttribute*, NodeVisitor*) {}
+};
+
+}
+
+#endif