//C++ header - Open Scene Graph - Copyright (C) 1998-2002 Robert Osfield
//Distributed under the terms of the GNU Library General Public License (LGPL)
//as published by the Free Software Foundation.

#ifndef OSGUTIL_INSERTIMPOSTORSVISITOR
#define OSGUTIL_INSERTIMPOSTORSVISITOR

#include <osg/NodeVisitor>
#include <osg/Impostor>

#include <osgUtil/Export>

namespace osgUtil {

/** Insert impostor nodes into scene graph.
  * For example of usage see src/Demos/osgimpostor.
  */
class OSGUTIL_EXPORT InsertImpostorsVisitor : public osg::NodeVisitor
{
    public:

        /// default to traversing all children.
        InsertImpostorsVisitor();
        
        void setImpostorThresholdRatio(float ratio) { _impostorThresholdRatio = ratio; }
        float getImpostorThresholdRatio() const { return _impostorThresholdRatio; }

        void setMaximumNumberOfNestedImpostors(unsigned int num) { _maximumNumNestedImpostors = num; }
        unsigned int getMaximumNumberOfNestedImpostors() const { return _maximumNumNestedImpostors; }

        /** empty visitor, make it ready for next traversal.*/        
        void reset();

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

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

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

        virtual void apply(osg::Impostor& node);
        
        /* insert the required impostors into the scene graph.*/
        void insertImpostors();
        
    protected:
    
        typedef std::vector< osg::Group* >  GroupList;
        typedef std::vector< osg::LOD* >    LODList;
        
        GroupList       _groupList;
        LODList         _lodList;        

        float           _impostorThresholdRatio;
        unsigned int    _maximumNumNestedImpostors;
        unsigned int    _numNestedImpostors;

};

}

#endif