From Farshid Lashkari, "As discussed, I've added the ability to handle Drawable objects within the NodeVisitor class. Here is an overview of the changes:

- Added apply(Drawable) and apply(Geometry) to NodeVisitor

- Added accept(NodeVisitor) method to Drawable/Geometry

- Added traverse(NodeVisitor) to Geode which calls accept(NodeVisitor) on all Drawables

- Updated CullVisitor to use new apply(Drawable) to handle drawables. The apply(Billboard) method still manually handles the drawables since it is depends on the billboard settings. I needed to disable the traverse within billboard to prevent duplicate traversal of drawables.

- Update other osgUtil node visitors (GLObjectsVisitor, IncrementalCompileOperation, ..) to use new apply(Drawable) method.
"

include/osg/Geometry

@@ -44,6 +44,8 @@ class OSG_EXPORT Geometry : public Drawable
         virtual Geometry* asGeometry() { return this; }
         virtual const Geometry* asGeometry() const { return this; }
 
+        virtual void accept(NodeVisitor& nv) { nv.apply(*this); }
+
         bool empty() const;
 
         typedef std::vector< osg::ref_ptr<osg::Array> >  ArrayList;