//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_APPVISITOR
#define OSGUTIL_APPVISITOR 1

#include <osg/NodeVisitor>
#include <osg/Node>
#include <osg/Geode>
#include <osg/Billboard>
#include <osg/LOD>
#include <osg/Switch>
#include <osg/LightSource>
#include <osg/Transform>
#include <osg/Projection>
#include <osg/Impostor>
#include <osg/OccluderNode>

#include <osgUtil/Export>

namespace osgUtil {

/**
 * Basic AppVisitor implementation for animating a scene.
 * This visitor traverses the scene graph, call each nodes appCallback if
 * it exists. 
 */
class OSGUTIL_EXPORT AppVisitor : public osg::NodeVisitor
{
    public:

        AppVisitor();
        virtual ~AppVisitor();

        virtual void reset();

        virtual void apply(osg::Node& node)         { handle_callbacks_and_traverse(node); }
        
        virtual void apply(osg::Geode& node)        { handle_geode_callbacks(node); }
        virtual void apply(osg::Billboard& node)    { handle_geode_callbacks(node); }
        
        virtual void apply(osg::LightSource& node)  { handle_callbacks_and_traverse(node); }
        
        virtual void apply(osg::Group& node)        { handle_callbacks_and_traverse(node); }
        virtual void apply(osg::Transform& node)    { handle_callbacks_and_traverse(node); }
        virtual void apply(osg::Projection& node)   { handle_callbacks_and_traverse(node); }
        virtual void apply(osg::Switch& node)       { handle_callbacks_and_traverse(node); }
        virtual void apply(osg::LOD& node)          { handle_callbacks_and_traverse(node); }
        virtual void apply(osg::Impostor& node)     { handle_callbacks_and_traverse(node); }
        virtual void apply(osg::OccluderNode& node) { handle_callbacks_and_traverse(node); }


    protected:

        /** prevent unwanted copy construction.*/
        AppVisitor(const AppVisitor&):osg::NodeVisitor() {}

        /** prevent unwanted copy operator.*/
        AppVisitor& operator = (const AppVisitor&) { return *this; }
        
        inline void handle_callbacks_and_traverse(osg::Node& node)
        {
            osg::NodeCallback* callback = node.getAppCallback();
            if (callback) (*callback)(&node,this);
            else if (node.getNumChildrenRequiringAppTraversal()>0) traverse(node);
        }

        inline void handle_geode_callbacks(osg::Geode& node)
        {
            osg::NodeCallback* callback = node.getAppCallback();
            if (callback) (*callback)(&node,this);
            else if (node.getNumChildrenRequiringAppTraversal()>0) traverse(node);
            
            // call the app callbacks on the drawables.
            for(unsigned int i=0;i<node.getNumDrawables();++i)
            {
                osg::Drawable::AppCallback* callback = node.getDrawable(i)->getAppCallback();
                if (callback) callback->app(this,node.getDrawable(i));
            }
            
        }
        
	
};

}

#endif