/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield
 *
 * This library is open source and may be redistributed and/or modified under
 * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
 * (at your option) any later version.  The full license is in LICENSE file
 * included with this distribution, and on the openscenegraph.org website.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * OpenSceneGraph Public License for more details.
*/
//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 overridden 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 ValueType>
        ValueType interpolate(float t, const range<ValueType>& r) const
        {
            return interpolate(t, r.minimum, r.maximum);
        }

    protected:
        virtual ~Interpolator() {}
    };

}

#endif