//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.
//osgParticle - Copyright (C) 2002 Marco Jez

#ifndef OSGPARTICLE_PROGRAM_
#define OSGPARTICLE_PROGRAM_ 1

#include <osgParticle/Export>
#include <osgParticle/ParticleProcessor>

#include <osg/Object>
#include <osg/Node>
#include <osg/NodeVisitor>
#include <osg/CopyOp>

namespace osgParticle
{

    /**    An abstract <CODE>ParticleProcessor</CODE> descendant for modifying particles "on the fly" 
        during the cull traversal.
        Descendants of this class must implement the <CODE>execute()</CODE> method, which should iterate 
        through all particles in the linked particle system and modify them somehow 
        (usually updating their velocity vector).
    */
    class OSGPARTICLE_EXPORT Program: public ParticleProcessor {
    public:
        Program();
        Program(const Program &copy, const osg::CopyOp &copyop = osg::CopyOp::SHALLOW_COPY);

        virtual const char *libraryName() const { return "osgParticle"; }
        virtual const char *className() const { return "Program"; }
        virtual bool isSameKindAs(const osg::Object *obj) { return dynamic_cast<const Program*>(obj) != 0; }
        virtual void accept(osg::NodeVisitor& nv) { if (nv.validNodeMask(*this)) { nv.pushOntoNodePath(this); nv.apply(*this); nv.popFromNodePath(); } }

    protected:
        virtual ~Program() {}
        Program &operator=(const Program &) { return *this; }

        /// Implementation of <CODE>ParticleProcessor::process()</CODE>. Do not call this method by yourself.
        inline void process(double dt);
        
        /// Execute the program on the particle system. Must be overriden in descendant classes.
        virtual void execute(double dt) = 0;

    private:
    };

    // INLINE FUNCTIONS

    inline void Program::process(double dt)
    {
        execute(dt);
    }
    
}

#endif