Math.h

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/*
 * True Reality Open Source Game and Simulation Engine
 * Copyright © 2021 Acid Rain Studios LLC
 *
 * This library is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License as published by the Free
 * Software Foundation; either version 3.0 of the License, or (at your option)
 * any later version.
 *
 * 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 GNU Lesser General Public License for more
 * details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * @author Maxim Serebrennik
 */

#pragma once

#include <trUtil/Export.h>

#include <osg/Math>

namespace trUtil::Math
{
    static const double PI = osg::PI;
    static const double PI_OVER_2 = osg::PI_2;
    static const double PI_OVER_4 = osg::PI_4;
    static const double TWO_PI = trUtil::Math::PI * 2.0;
    static const double FOUR_PI = trUtil::Math::PI * 4.0;
    static const double SQRT_PI = 1.77245385090551602729816748334;
    static const double E = 2.7182818284590452354;
    static const double LOG_OF_2 = osg::LN_2;
    static const double INV_LOG_OF_2 = osg::INVLN_2;
    static const double ONE_OVER_PI = 1.0 / trUtil::Math::PI;
    static const double ONE80_OVER_PI = (180.0*ONE_OVER_PI);

    inline void SinCos(double x, double& sinVal, double& cosVal)
    {
        sinVal = sin(x);
        cosVal = cos(x);
    }

    inline void SinCos(float x, float& sinVal, float& cosVal)
    {
        sinVal = sin(x);
        cosVal = cos(x); // Might benefit from trig identities
    }

    inline double Deg2Rad(double degree)
    {
        return osg::DegreesToRadians(degree);
    }

    inline float Deg2Rad(float degree)
    {
        return osg::DegreesToRadians(degree);
    }

    inline double Rad2Deg(double radian)
    {
        return osg::RadiansToDegrees(radian);
    }

    inline float Rad2Deg(float radian)
    {
        return osg::RadiansToDegrees(radian);
    }

    inline double CheckState(double state)
    {
        if (state == 0)
            return 0;
        else if (state < 0)
            return -1;
        else
            return 1;
    }

    inline float CheckState(float state)
    {
        if (state == 0)
            return 0;
        else if (state < 0)
            return -1;
        else
            return 1;
    }

    template <typename T>
    inline T Lerp(T from, T to, T alpha)
    {
        return from + ((to - from) * alpha);
    }
}