Chris@16: // Boost.Geometry (aka GGL, Generic Geometry Library)
Chris@16: 
Chris@16: // Copyright (c) 2011-2012 Barend Gehrels, Amsterdam, the Netherlands.
Chris@16: 
Chris@16: // Use, modification and distribution is subject to the Boost Software License,
Chris@16: // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: #ifndef BOOST_GEOMETRY_STRATEGIES_SPHERICAL_SSF_HPP
Chris@16: #define BOOST_GEOMETRY_STRATEGIES_SPHERICAL_SSF_HPP
Chris@16: 
Chris@16: #include <boost/mpl/if.hpp>
Chris@16: #include <boost/type_traits.hpp>
Chris@16: 
Chris@16: #include <boost/geometry/core/cs.hpp>
Chris@16: #include <boost/geometry/core/access.hpp>
Chris@16: #include <boost/geometry/core/radian_access.hpp>
Chris@16: 
Chris@16: #include <boost/geometry/util/math.hpp>
Chris@101: #include <boost/geometry/util/promote_floating_point.hpp>
Chris@101: #include <boost/geometry/util/select_calculation_type.hpp>
Chris@16: 
Chris@16: #include <boost/geometry/strategies/side.hpp>
Chris@16: //#include <boost/geometry/strategies/concepts/side_concept.hpp>
Chris@16: 
Chris@16: 
Chris@16: namespace boost { namespace geometry
Chris@16: {
Chris@16: 
Chris@16: 
Chris@16: namespace strategy { namespace side
Chris@16: {
Chris@16: 
Chris@101: #ifndef DOXYGEN_NO_DETAIL
Chris@101: namespace detail
Chris@101: {
Chris@101: 
Chris@101: template <typename T>
Chris@101: int spherical_side_formula(T const& lambda1, T const& delta1,
Chris@101:                            T const& lambda2, T const& delta2,
Chris@101:                            T const& lambda, T const& delta)
Chris@101: {
Chris@101:     // Create temporary points (vectors) on unit a sphere
Chris@101:     T const cos_delta1 = cos(delta1);
Chris@101:     T const c1x = cos_delta1 * cos(lambda1);
Chris@101:     T const c1y = cos_delta1 * sin(lambda1);
Chris@101:     T const c1z = sin(delta1);
Chris@101: 
Chris@101:     T const cos_delta2 = cos(delta2);
Chris@101:     T const c2x = cos_delta2 * cos(lambda2);
Chris@101:     T const c2y = cos_delta2 * sin(lambda2);
Chris@101:     T const c2z = sin(delta2);
Chris@101: 
Chris@101:     // (Third point is converted directly)
Chris@101:     T const cos_delta = cos(delta);
Chris@101: 
Chris@101:     // Apply the "Spherical Side Formula" as presented on my blog
Chris@101:     T const dist
Chris@101:         = (c1y * c2z - c1z * c2y) * cos_delta * cos(lambda)
Chris@101:         + (c1z * c2x - c1x * c2z) * cos_delta * sin(lambda)
Chris@101:         + (c1x * c2y - c1y * c2x) * sin(delta);
Chris@101: 
Chris@101:     T zero = T();
Chris@101:     return dist > zero ? 1
Chris@101:         : dist < zero ? -1
Chris@101:         : 0;
Chris@101: }
Chris@101: 
Chris@101: }
Chris@101: #endif // DOXYGEN_NO_DETAIL
Chris@16: 
Chris@16: /*!
Chris@16: \brief Check at which side of a Great Circle segment a point lies
Chris@16:          left of segment (> 0), right of segment (< 0), on segment (0)
Chris@16: \ingroup strategies
Chris@16: \tparam CalculationType \tparam_calculation
Chris@16:  */
Chris@16: template <typename CalculationType = void>
Chris@16: class spherical_side_formula
Chris@16: {
Chris@16: 
Chris@16: public :
Chris@16:     template <typename P1, typename P2, typename P>
Chris@16:     static inline int apply(P1 const& p1, P2 const& p2, P const& p)
Chris@16:     {
Chris@101:         typedef typename promote_floating_point
Chris@16:             <
Chris@101:                 typename select_calculation_type_alt
Chris@101:                     <
Chris@101:                         CalculationType,
Chris@101:                         P1, P2, P
Chris@101:                     >::type
Chris@101:             >::type calculation_type;
Chris@16: 
Chris@101:         calculation_type const lambda1 = get_as_radian<0>(p1);
Chris@101:         calculation_type const delta1 = get_as_radian<1>(p1);
Chris@101:         calculation_type const lambda2 = get_as_radian<0>(p2);
Chris@101:         calculation_type const delta2 = get_as_radian<1>(p2);
Chris@101:         calculation_type const lambda = get_as_radian<0>(p);
Chris@101:         calculation_type const delta = get_as_radian<1>(p);
Chris@16: 
Chris@101:         return detail::spherical_side_formula(lambda1, delta1,
Chris@101:                                               lambda2, delta2,
Chris@101:                                               lambda, delta);
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: #ifndef DOXYGEN_NO_STRATEGY_SPECIALIZATIONS
Chris@16: namespace services
Chris@16: {
Chris@16: 
Chris@16: /*template <typename CalculationType>
Chris@16: struct default_strategy<spherical_polar_tag, CalculationType>
Chris@16: {
Chris@16:     typedef spherical_side_formula<CalculationType> type;
Chris@16: };*/
Chris@16: 
Chris@16: template <typename CalculationType>
Chris@16: struct default_strategy<spherical_equatorial_tag, CalculationType>
Chris@16: {
Chris@16:     typedef spherical_side_formula<CalculationType> type;
Chris@16: };
Chris@16: 
Chris@16: template <typename CalculationType>
Chris@16: struct default_strategy<geographic_tag, CalculationType>
Chris@16: {
Chris@16:     typedef spherical_side_formula<CalculationType> type;
Chris@16: };
Chris@16: 
Chris@16: }
Chris@16: #endif
Chris@16: 
Chris@16: }} // namespace strategy::side
Chris@16: 
Chris@16: }} // namespace boost::geometry
Chris@16: 
Chris@16: 
Chris@16: #endif // BOOST_GEOMETRY_STRATEGIES_SPHERICAL_SSF_HPP