/*  -*-c++-*- 
 *  Copyright (C) 2008 Cedric Pinson <mornifle@plopbyte.net>
 *
 * 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.
*/

#ifndef OSGANIMATION_EASE_MOTION_H
#define OSGANIMATION_EASE_MOTION_H

namespace osgAnimation {


    struct OutBounceFunction 
    {
        inline static void getValueAt(float t, float& result) 
        { 
            if ((t) < (1/2.75)) 
            {
                result = 7.5625 * t * t;
            } 
            else if (t < (2/2.75)) 
            {
                t = t - (1.5/2.75);
                result = 7.5625* t * t + .75;
            }
            else if (t < (2.5/2.75)) 
            {
                t = t - (2.25/2.75);
                result = 7.5625 * t * t + .9375;
            }
            else 
            {
                t = t - (2.625/2.75);
                result = 7.5625* t * t + .984375;
            }
        }
    };

    struct InBounceFunction 
    {
        inline static void getValueAt(float t, float& result) 
        { 
            OutBounceFunction::getValueAt(1-t, result);
            result = 1 - result;
        }
    };

    struct InOutBounceFunction 
    {
        inline static void getValueAt(float t, float& result) 
        { 
            if (t < 0.5) 
            {
                InBounceFunction::getValueAt(t * 2, result);
                result *= 0.5;
            } 
            else 
            {
                OutBounceFunction::getValueAt(t * 2 - 1 , result);
                result = result * 0.5 + 0.5;
            }
        }
    };


    /// Linear function
    struct LinearFunction 
    {
        inline static void getValueAt(float t, float& result) { result = t;}
    };

  
    /// Quad function
    struct OutQuadFunction 
    {
        inline static void getValueAt(float t, float& result) { result = - (t * (t -2.0));}
    };

    struct InQuadFunction 
    {
        inline static void getValueAt(float t, float& result) { result = t*t;}
    };
    struct InOutQuadFunction 
    {
        inline static void getValueAt(float t, float& result) 
        { 
            t = t * 2.0;
            if (t < 1.0)
                result = 0.5 * t * t;
            else 
            {
                t = t - 1.0;
                result = - 0.5 * t * ( t - 2) - 1;
            }
        }
    };


    /// Cubic function
    struct OutCubicFunction 
    {
        inline static void getValueAt(float t, float& result) { t = t-1.0; result = t*t*t + 1;}
    };
    struct InCubicFunction 
    {
        inline static void getValueAt(float t, float& result) { result = t*t*t;}
    };
    struct InOutCubicFunction 
    {
        inline static void getValueAt(float t, float& result) 
        { 
            t = t * 2;
            if (t < 1.0)
                result = 0.5 * t * t * t;
            else {
                t = t - 2;
                result = 0.5 * t * t * t + 2;
            }
        }
    };
 

    /// Quart function
    struct InQuartFunction 
    {
        inline static void getValueAt(float t, float& result) { result = t*t*t*t*t;}
    };

    struct OutQuartFunction
    {
        inline static void getValueAt(float t, float& result) { t = t - 1; result = - (t*t*t*t -1); }
    };

    struct InOutQuartFunction
    {
        inline static void getValueAt(float t, float& result) 
        {
            t = t * 2.0;
            if ( t < 1)
                result = 0.5*t*t*t*t;
            else
            {
                t -= 2.0;
                result = -0.5 * (t*t*t*t -2);
            }
        }
    };



    class Motion
    {
    public:
        typedef float value_type;
        enum TimeBehaviour 
        {
            CLAMP,
            LOOP,
        };
        Motion(float startValue = 0, float duration = 1, float changeValue = 1, TimeBehaviour tb = CLAMP) : _time(0), _b(startValue), _c(changeValue), _d(duration), _behaviour(tb) {}
        virtual ~Motion() {}
        void reset() { setTime(0);}
        float getTime() const { return _time; }
        void update(float dt)
        {
            _time += dt;
            switch (_behaviour) 
            {
            case CLAMP:
                if (_time > _d)
                    _time = _d;
                else if (_time < 0.0)
                    _time = 0.0;
                break;
            case LOOP:
                _time = fmodf(_time, _d);
                break;
            }
        }
    
        void setTime(float time) { _time = time; update(0);}
        void getValue(value_type& result) const { getValueAt(_time, result); }
        value_type getValue() const
        {
            value_type result;
            getValueAt(_time, result);
            return result;
        }

        void getValueAt(float time, value_type& result) const
        {
            getValueInNormalizedRange(time/_d, result);
            result = result * _c + _b;
        }
        value_type getValueAt(float time) const
        { 
            value_type result;
            getValueAt(time, result);
            return result;
        }

        virtual void getValueInNormalizedRange(float t, value_type& result) const = 0;

    protected:      
        float _time;
        float _b;
        float _c;
        float _d;
        TimeBehaviour _behaviour;
    };



    template <typename T>
    struct MathMotionTemplate : public Motion
    {
        MathMotionTemplate(float startValue = 0, float duration = 1, float changeValue = 1, TimeBehaviour tb = CLAMP) : Motion(startValue, duration, changeValue, tb) {}
        virtual void getValueInNormalizedRange(float t, value_type& result) const { T::getValueAt(t, result); }
    };

    template <class T>
    struct SamplerMotionTemplate : public Motion
    {
        T _sampler;
        SamplerMotionTemplate(float startValue = 0, float duration = 1, float changeValue = 1, TimeBehaviour tb = CLAMP) : Motion(startValue, duration, changeValue, tb) {}
        T& getSampler() { return _sampler;}
        const T& getSampler() const { return _sampler;}
        virtual void getValueInNormalizedRange(float t, value_type& result) const
        { 
            if (!_sampler.getKeyframeContainer()) 
            {
                result = 0;
                return;
            }
            float size = _sampler.getEndTime() - _sampler.getStartTime();
            t = t * size + _sampler.getStartTime();
            _sampler.getValueAt(t, result);
        }
    };



    // linear
    typedef MathMotionTemplate<LinearFunction > LinearMotion;

    // quad
    typedef MathMotionTemplate<OutQuadFunction > OutQuadMotion;
    typedef MathMotionTemplate<InQuadFunction> InQuadMotion;
    typedef MathMotionTemplate<InOutQuadFunction> InOutQuadMotion;

    // cubic
    typedef MathMotionTemplate<OutCubicFunction > OutCubicMotion;
    typedef MathMotionTemplate<InCubicFunction> InCubicMotion;
    typedef MathMotionTemplate<InOutCubicFunction> InOutCubicMotion;

    // quart
    typedef MathMotionTemplate<OutQuartFunction > OutQuartMotion;
    typedef MathMotionTemplate<InQuartFunction> InQuartMotion;
    typedef MathMotionTemplate<InOutQuartFunction> InOutQuartMotion;


    // bounce
    typedef MathMotionTemplate<OutBounceFunction > OutBounceMotion;
    typedef MathMotionTemplate<InBounceFunction> InBounceMotion;
    typedef MathMotionTemplate<InOutBounceFunction> InOutBounceMotion;


}

#endif