//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_INTERPOLATOR_
#define OSGPARTICLE_INTERPOLATOR_

#include <osgParticle/range>

#include <osg/CopyOp>
#include <osg/Object>
#include <osg/Vec2>
#include <osg/Vec3>
#include <osg/Vec4>

namespace osgParticle
{

    /// An abstract base class for implementing interpolators.
    class Interpolator : public osg::Object {
    public:
        Interpolator()
        : osg::Object() {}
        
        Interpolator(const Interpolator &copy, const osg::CopyOp &copyop = osg::CopyOp::SHALLOW_COPY)
        : osg::Object(copy, copyop) {}
        
        virtual const char *libraryName() const { return "osgParticle"; }
        virtual const char *className() const { return "Interpolator"; }
        virtual bool isSameKindAs(const osg::Object *obj) const { return dynamic_cast<const Interpolator *>(obj) != 0; }
                
        /// Interpolate between floats. Must be overriden in descendant classes.
        virtual float interpolate(float t, float y1, float y2) const = 0;    
        
        /// Interpolate between 2-dimensional vectors. Default behavior is to interpolate each component separately.
        virtual osg::Vec2 interpolate(float t, const osg::Vec2 &y1, const osg::Vec2 &y2) const
        {
            return osg::Vec2(
                interpolate(t, y1.x(), y2.x()),
                interpolate(t, y1.y(), y2.y())
            );
        }

        /// Interpolate between 3-dimensional vectors. Default behavior is to interpolate each component separately.
        virtual osg::Vec3 interpolate(float t, const osg::Vec3 &y1, const osg::Vec3 &y2) const
        {
            return osg::Vec3(
                interpolate(t, y1.x(), y2.x()),
                interpolate(t, y1.y(), y2.y()),
                interpolate(t, y1.z(), y2.z())
            );
        }
        
        /// Interpolate between 4-dimensional vectors. Default behavior is to interpolate each component separately.
        virtual osg::Vec4 interpolate(float t, const osg::Vec4 &y1, const osg::Vec4 &y2) const
        {
            return osg::Vec4(
                interpolate(t, y1.x(), y2.x()),
                interpolate(t, y1.y(), y2.y()),
                interpolate(t, y1.z(), y2.z()),
                interpolate(t, y1.w(), y2.w())
            );
        }
        
        template<class T_>
        T_ interpolate(float t, const range<T_> &r) const
        {
            return interpolate(t, r.minimum, r.maximum);
        }
        
    protected:
        virtual ~Interpolator() {}
    };

}

#endif