fmath.h

#pragma once
/*
 * Copyright 2010-2016 OpenXcom Developers.
 *
 * This file is part of OpenXcom.
 *
 * OpenXcom 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 3 of the License, or
 * (at your option) any later version.
 *
 * OpenXcom 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 OpenXcom.  If not, see <http://www.gnu.org/licenses/>.
 */
#include <algorithm>
#include <cfloat>
#define _USE_MATH_DEFINES
#include <cmath>

#ifndef M_PI
#define M_PI       3.14159265358979323846
#define M_PI_2     1.57079632679489661923
#define M_PI_4     0.785398163397448309616
#endif

// Float operations

inline bool AreSame(float l, float r)
{
	return std::fabs(l-r) <= FLT_EPSILON * std::max(1.0f, std::max(std::fabs(l), std::fabs(r)));
}

inline bool AreSame(double l, double r)
{
	return std::fabs(l-r) <= DBL_EPSILON * std::max(1.0, std::max(std::fabs(l), std::fabs(r)));;
}

inline float Round(float x)
{
	return x < 0.0f ? std::ceil(x - 0.5f) : std::floor(x + 0.5f);
}

inline double Round(double x)
{
	return x < 0.0 ? std::ceil(x - 0.5) : std::floor(x + 0.5);
}

// Number operations

template <class _Tx>
inline _Tx Sqr(const _Tx& x)
{
	return x * x;
}

template <class _Tx>
inline _Tx Sign(const _Tx& x)
{
	return (_Tx(0) < x) - (x < _Tx(0));
}

template <class _Tx>
inline _Tx Clamp(const _Tx& x, const _Tx& min, const _Tx& max)
{
	return std::min(std::max(x, min), max);
}

// Degree operations

inline double Deg2Rad(double deg)
{
	return deg * M_PI / 180.0;
}

inline double Rad2Deg(double rad)
{
	return rad / M_PI * 180.0;
}

inline double Xcom2Rad(int deg)
{
	return deg * 0.125 * M_PI / 180.0;
}

inline double Nautical(double x)
{
	return x * (1 / 60.0) * (M_PI / 180.0);
}