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- /*
- * Copyright (C) 2021 Christopher J. Howard
- *
- * This file is part of Antkeeper source code.
- *
- * Antkeeper source code 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.
- *
- * Antkeeper source code 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 Antkeeper source code. If not, see <http://www.gnu.org/licenses/>.
- */
-
- #ifndef ANTKEEPER_COORDINATES_ECLIPTIC_HPP
- #define ANTKEEPER_COORDINATES_ECLIPTIC_HPP
-
- #include "coordinates/rectangular.hpp"
- #include "coordinates/spherical.hpp"
- #include "utility/fundamental-types.hpp"
- #include <cmath>
-
- namespace coordinates {
-
- namespace rectangular {
-
- /// Rectangular coordinate system with the plane of the Earth's orbit as the fundamental plane. This is a right-handed coordinate system with the x-axis pointing to the vernal equinox, the y-axis pointing east, and the z-axis is the north orbital pole.
- namespace ecliptic {
-
- /**
- * Produces a matrix which rotates rectangular coordinates from ecliptic space into equatorial space.
- *
- * @param ecl Obliquity of the ecliptic, in radians.
- * @return Rotation matrix.
- *
- * @see coordinates::rectangular::equatorial
- */
- template <class T>
- math::matrix3<T> to_equatorial(T ecl);
-
- /**
- * Rotates rectangular coordinates from ecliptic space into equatorial space.
- *
- * @param v Rectangular coordinates in ecliptic space.
- * @param ecl Obliquity of the ecliptic, in radians.
- * @return Rectangular coordinates in equatorial space.
- *
- * @see coordinates::rectangular::equatorial
- */
- template <class T>
- math::vector3<T> to_equatorial(const math::vector3<T>& v, T ecl);
-
- /**
- * Produces a matrix which rotates rectangular coordinates from ecliptic space into local horizontal space.
- *
- * @param ecl Obliquity of the ecliptic, in radians.
- * @param lat Observer's latitude, in radians.
- * @param lst Local sidereal time, in radians.
- * @return Rotation matrix.
- *
- * @see coordinates::rectangular::horizontal
- */
- template <class T>
- math::matrix3<T> to_horizontal(T ecl, T lat, T lst);
-
- /**
- * Rotates rectangular coordinates from ecliptic space into local horizontal space.
- *
- * @param v Rectangular coordinates in ecliptic space.
- * @param ecl Obliquity of the ecliptic, in radians.
- * @param lat Observer's latitude, in radians.
- * @param lst Local sidereal time, in radians.
- * @return Rectangular coordinates in local horizontal space.
- *
- * @see coordinates::rectangular::horizontal
- */
- template <class T>
- math::vector3<T> to_horizontal(const math::vector3<T>& v, T ecl, T lat, T lst);
-
- } // namespace ecliptic
-
- } // namespace rectangular
-
- namespace spherical {
-
- /// Spherical ecliptic coordinate system.
- namespace ecliptic {
-
- /**
- * Rotates spherical coordinates from ecliptic space into equatorial space.
- *
- * @param v Spherical coordinates in ecliptic space, in the ISO order of radial distance, ecliptic latitude (radians), and ecliptic longitude (radians).
- * @param ecl Obliquity of the ecliptic, in radians.
- * @return Spherical coordinates in equatorial space, in the ISO order of radial distance, declination (radians), and right ascension (radians).
- *
- * @see coordinates::spherical::equatorial
- */
- template <class T>
- math::vector3<T> to_equatorial(const math::vector3<T>& v, T ecl);
-
- /**
- * Rotates spherical coordinates from ecliptic space into local horizontal space.
- *
- * @param v Spherical coordinates in ecliptic space, in the ISO order of radial distance, ecliptic latitude (radians), and ecliptic longitude (radians).
- * @param ecl Obliquity of the ecliptic, in radians.
- * @param lat Observer's latitude, in radians.
- * @param lst Local sidereal time, in radians.
- * @return Spherical coordinates in local horizontal space, in the ISO order of radial distance, altitude (radians), and azimuth (radians).
- *
- * @see coordinates::spherical::horizontal
- */
- template <class T>
- math::vector3<T> to_horizontal(const math::vector3<T>& v, T ecl, T lat, T lst);
-
- } // namespace ecliptic
-
- } // namespace spherical
-
- namespace rectangular {
-
- namespace ecliptic {
-
- template <class T>
- math::matrix3<T> to_equatorial(T ecl)
- {
- const T c_ecl = std::cos(ecl);
- const T s_ecl = std::sin(ecl);
-
- return math::matrix3<T>
- {
- T(1.0), T(0.0), T(0.0),
- T(0.0), c_ecl, s_ecl,
- T(0.0), -s_ecl, c_ecl
- };
- }
-
- template <class T>
- math::vector3<T> to_equatorial(const math::vector3<T>& v, T ecl)
- {
- return to_equatorial<T>(ecl) * v;
- }
-
- template <class T>
- math::matrix3<T> to_horizontal(T ecl, T lat, T lst)
- {
- const T c_ecl = std::cos(ecl);
- const T s_ecl = std::sin(ecl);
- const T c_lat = std::cos(lat);
- const T s_lat = std::sin(lat);
- const T c_lst = std::cos(lst);
- const T s_lst = std::sin(lst);
-
- return math::matrix3<T>
- {
- s_lat * c_lst, s_lst, c_lat * c_lst,
- s_lat * s_lst * c_ecl - c_lat * s_ecl, -c_lst * c_ecl, c_lat * s_lst * c_ecl + s_lat * s_ecl,
- s_lat * s_lst * -s_ecl - c_lat * c_ecl, c_lst * s_ecl, c_lat * s_lst * -s_ecl + s_lat * c_ecl
- };
- }
-
- template <class T>
- math::vector3<T> to_horizontal(const math::vector3<T>& v, T ecl, T lat, T lst)
- {
- return to_horizontal<T>(ecl, lat, lst) * v;
- }
-
- } // namespace ecliptic
-
- } // namespace rectangular
-
- namespace spherical {
-
- namespace ecliptic {
-
- template <class T>
- math::vector3<T> to_equatorial(const math::vector3<T>& v, T ecl)
- {
- return coordinates::rectangular::to_spherical<T>
- (
- coordinates::rectangular::ecliptic::to_equatorial<T>
- (
- coordinates::spherical::to_rectangular<T>(v),
- ecl
- )
- );
- }
-
- template <class T>
- math::vector3<T> to_horizontal(const math::vector3<T>& v, T ecl, T lat, T lst)
- {
- return coordinates::rectangular::to_spherical<T>
- (
- coordinates::rectangular::ecliptic::to_horizontal<T>
- (
- coordinates::spherical::to_rectangular<T>(v),
- ecl,
- lat,
- lst
- )
- );
- }
-
- } // namespace ecliptic
-
- } // namespace spherical
-
- } // namespace coordinates
-
- #endif // ANTKEEPER_COORDINATES_ECLIPTIC_HPP
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