/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2005 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 OSGUTIL_GLOBJECTSVISITOR
#define OSGUTIL_GLOBJECTSVISITOR 1

#include <osg/NodeVisitor>
#include <osg/Geode>
#include <osg/State>

#include <osgUtil/Export>

namespace osgUtil {

/** Visitor for traversing scene graph and setting each osg::Drawable's _useDisplayList flag, 
  * with option to immediately compile osg::Drawable OpenGL Display lists and
  * osg::StateAttribute's.
  */
class OSGUTIL_EXPORT GLObjectsVisitor : public osg::NodeVisitor
{
    public:

        /** Operation modes of the.*/
        enum ModeValues
        {
            SWITCH_ON_DISPLAY_LISTS             = 0x1,
            SWITCH_OFF_DISPLAY_LISTS            = 0x2,
            COMPILE_DISPLAY_LISTS               = 0x4,
            COMPILE_STATE_ATTRIBUTES            = 0x8,
            RELEASE_DISPLAY_LISTS               = 0x10,
            RELEASE_STATE_ATTRIBUTES            = 0x20,
            SWITCH_ON_VERTEX_BUFFER_OBJECTS     = 0x40,
            SWITCH_OFF_VERTEX_BUFFER_OBJECTS    = 0x80
        };
        
        typedef unsigned int Mode;

        /** Construct a GLObjectsVisitor to traverse all children, operating on
          * node according to specified mode, such as to compile or release 
          * display list/texture objects etc. Default mode is to compile 
          * GL objects.
          */
        GLObjectsVisitor(Mode mode=COMPILE_DISPLAY_LISTS|COMPILE_STATE_ATTRIBUTES);
        
        /** Set the operational mode of what operations to do on the scene graph.*/
        void setMode(Mode mode) { _mode = mode; }

        /** Get the operational mode.*/
        Mode getMode() const { return _mode; }
        

        /** Set the State to use during traversal. */
        void setState(osg::State* state)
        {
            _state = state;
        }
        
        osg::State* getState()
        {
            return _state.get();
        }
        

        /** Simply traverse using standard NodeVisitor traverse method.*/
        virtual void apply(osg::Node& node);
        
        /** For each Geode visited set the display list usage according to the 
          * _displayListMode.
          */
        virtual void apply(osg::Geode& node);

        void apply(osg::Drawable& drawable);
        void apply(osg::StateSet& stateset);

    protected:

        Mode _mode;

        osg::ref_ptr<osg::State> _state;

};

}

#endif