/***************************************************************************
 *   Copyright (C) 2012 by Nicolas PASCAL                                  *
 *   nicolas.pascal@icare.univ-lille1.fr                                   *
 *                                                                         *
 *   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     *
 *   (at your option) 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.             *
 ***************************************************************************/

/***************************************************************************
 *  Descrition :                                                           *
 *  implements common geometry constants and functions                     *
 *                                                                         *
 *  History :                                                              *
 *  2012/02/03 : start                                                     *
 ***************************************************************************/

#ifndef GEOMETRY_COMMON_H
#define GEOMETRY_COMMON_H

#include <cmath>

/** PI multiplied by 2 */
static const double M_2PI = 2. * M_PI;
/** PI divided by 2 */
// static const double M_PI_2 = M_PI / 2.;

/** degrees to radians conversion constant */
const double DEG2RAD = double ( M_PI ) / double ( 180.);
/** radians to degrees conversion constant */
const double RAD2DEG = double ( 180. ) * double ( M_1_PI );

/**
 * @brief convert an angle in degrees to radians
 * @param degrees angle to convert in degrees
 * @return angle in radians
 */
inline const double radians (const double alpha) {
    return DEG2RAD * alpha;
};
/**
 * @brief convert an angle in radians to degrees
 * @param radians angle to convert in radians
 * @return angle in degrees
 */
inline const double degrees (const double alpha) {
    return RAD2DEG * alpha;
};

/**
 * @brief format a latitude to be in the range [-90, 90]
 * @param lat any latitude
 * @return the latitude in the range [-90, 90]
 */
inline double format_lat (double lat) {
    while (lat < - 90.)
        lat = -180. - lat;
    while (lat > 90.)
        lat = 180. - lat;
    return lat;
};

/**
 * @brief format a longitude to be in the range [-180, 180[
 * @param lon any longitude
 * @return the longitude in the range [-180, 180[
 */
inline double format_lon (double lon) {
    while (lon < - 180.)
        lon += 360.;
    while (lon >= 180.)
        lon -= 360.;
    return lon;
};

#endif