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.
"

src/osg/Geode.cpp

@@ -48,6 +48,16 @@ Geode::~Geode()
     }
 }
 
+void Geode::traverse(NodeVisitor& nv)
+{
+    for(DrawableList::iterator itr=_drawables.begin();
+        itr!=_drawables.end();
+        ++itr)
+    {
+        (*itr)->accept(nv);
+    }
+}
+
 bool Geode::addDrawable( Drawable *drawable )
 {
     if (drawable /* && !containsDrawable(drawable)*/)