//C++ header - Open Scene Graph - Copyright (C) 1998-2001 Robert Osfield
//Distributed under the terms of the GNU Library General Public License (LGPL)
//as published by the Free Software Foundation.

#ifndef OSGUTIL_VISUALSREQUIREMENTSVISITOR
#define OSGUTIL_VISUALSREQUIREMENTSVISITOR 1

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

#include <osgUtil/Export>

namespace osgUtil {

/** A visitor for traversing a scene graph establishing the OpenGL visuals are required
  * to support rendering of that scene graph.  The results can then be used by
  * applications to set up there windows with the correct visuals.  Have a look at
  * src/osgGLUT/Viewer.cpp's Viewer::open() method for an example how to use it.
  */
class OSGUTIL_EXPORT VisualsRequirementsVisitor : public osg::NodeVisitor
{
    public:

        /** Default to traversing all children, and reqiresDoubleBuffer,
          * requiresRGB and requiresDepthBuffer to true and with
          * alpha and stencil off.*/
        VisualsRequirementsVisitor();
        
        
        void setRequiresDoubleBuffer(const bool flag) { _requiresDoubleBuffer = flag; }

        const bool requiresDoubleBuffer() const { return _requiresDoubleBuffer; }


        void setRequiresRGB(const bool flag) { _requiresRBG = flag; }

        const bool requiresRGB() const { return _requiresRBG; }


        void setRequiresDepthBuffer(const bool flag) { _requiresDepthBuffer = flag; }

        const bool requiresDepthBuffer() const { return _requiresDepthBuffer; }


        void setMinimumNumAlphaBits(const unsigned int bits) { _minimumNumberAlphaBits = bits; }

        const unsigned int getMinimumNumAlphaBits() const { return _minimumNumberAlphaBits; }

        const bool requiresAlphaBuffer() const { return _minimumNumberAlphaBits!=0; }


        void setMinimumNumStencilBits(const unsigned int bits) { _minimumNumberStencilBits = bits; }

        const unsigned int getMinimumNumStencilBits() const { return _minimumNumberStencilBits; }
        
        const bool requiresStencilBuffer() const { return _minimumNumberStencilBits!=0; }


        virtual void applyStateSet(osg::StateSet& stateset);

        virtual void apply(osg::Node& node);

        virtual void apply(osg::Geode& geode);

        virtual void apply(osg::Impostor& impostor);
        
    protected:
    
        bool            _requiresDoubleBuffer;
        bool            _requiresRBG;
        bool            _requiresDepthBuffer;
        unsigned int    _minimumNumberAlphaBits;
        unsigned int    _minimumNumberStencilBits;

};

};

#endif