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/osgUtil/GLObjectsVisitor.cpp

@@ -61,18 +61,7 @@ void GLObjectsVisitor::apply(osg::Geode& node)
         apply(*(node.getStateSet()));
     }
 
-    for(unsigned int i=0;i<node.getNumDrawables();++i)
-    {
-        osg::Drawable* drawable = node.getDrawable(i);
-        if (drawable)
-        {
-            apply(*drawable);
-            if (drawable->getStateSet())
-            {
-                apply(*(drawable->getStateSet()));
-            }
-        }
-    }
+    traverse(node);
 
     bool programSetAfter = _lastCompiledProgram.valid();
     if (!programSetBefore && programSetAfter)
@@ -120,6 +109,11 @@ void GLObjectsVisitor::apply(osg::Drawable& drawable)
     {
         drawable.releaseGLObjects(_renderInfo.getState());
     }
+
+    if (drawable.getStateSet())
+    {
+        apply(*(drawable.getStateSet()));
+    }
 }
 
 void GLObjectsVisitor::apply(osg::StateSet& stateset)