/*

 *  The Mana World

 *  Copyright (C) 2006  The Mana World Development Team

 *

 *  This file is part of The Mana World.

 *

 *  This program is free software; you can redistribute it and/or modify

 *  it under the terms of the GNU General Public License as published by

 *  the Free Software Foundation; either version 2 of the License, or

 *  any later version.

 *

 *  This program 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

 *  GNU General Public License for more details.

 *

 *  You should have received a copy of the GNU General Public License

 *  along with this program; if not, write to the Free Software

 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

#include <cmath>

/**

 * Returns a random numeric value that is larger than or equal min and smaller

 * than max

 */

enum ChangeFunc

{

    FUNC_NONE,

    FUNC_SINE,

    FUNC_SAW,

    FUNC_TRIANGLE,

    FUNC_SQUARE

};

template <typename T> struct ParticleEmitterProp

{

    ParticleEmitterProp():

        changeFunc(FUNC_NONE)

    {

    }

    void set(T min, T max)

    {

        minVal=min; maxVal=max;

    }

    void set(T val)

    {

        set(val, val);

    }

    void setFunction(ChangeFunc func, T amplitude, int period, int phase)

    {

        changeFunc = func;

        changeAmplitude = amplitude;

        changePeriod = period;

        changePhase = phase;

    }

    T value(int tick)

    {

        tick += changePhase;

        T val = (T) (minVal + (maxVal - minVal) * (rand() / ((double) RAND_MAX + 1)));

        switch (changeFunc)

        {

            case FUNC_SINE:

                val += (T) std::sin(M_PI * 2 * ((double)(tick%changePeriod) / (double)changePeriod)) * changeAmplitude;

                break;

            case FUNC_SAW:

                val += (T) (changeAmplitude * ((double)(tick%changePeriod) / (double)changePeriod)) * 2 - changeAmplitude;

                break;

            case FUNC_TRIANGLE:

                if ((tick%changePeriod) * 2 < changePeriod)

                {

                    val += changeAmplitude - (T)((tick%changePeriod) / (double)changePeriod) * changeAmplitude * 4;

                } else {

                    val += changeAmplitude * -3 + (T)((tick%changePeriod) / (double)changePeriod) * changeAmplitude * 4;

                    // I have no idea why this works but it does

                }

                break;

            case FUNC_SQUARE:

                if ((tick%changePeriod) * 2 < changePeriod)

                {

                    val += changeAmplitude;

                } else {

                    val -= changeAmplitude;

                }

                break;

            case FUNC_NONE:

            default:

                //nothing

                break;

        }

        return val;

    }

    T minVal;

    T maxVal;

    ChangeFunc changeFunc;

    T changeAmplitude;

    int changePeriod;

    int changePhase;

};