1 // Boost.Geometry (aka GGL, Generic Geometry Library)
2
3 // Copyright (c) 2011-2012 Barend Gehrels, Amsterdam, the Netherlands.
4
5 // This file was modified by Oracle on 2016.
6 // Modifications copyright (c) 2016, Oracle and/or its affiliates.
7 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
8
9 // Use, modification and distribution is subject to the Boost Software License,
10 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
11 // http://www.boost.org/LICENSE_1_0.txt)
12
13 #ifndef BOOST_GEOMETRY_STRATEGIES_SPHERICAL_SSF_HPP
14 #define BOOST_GEOMETRY_STRATEGIES_SPHERICAL_SSF_HPP
15
16
17 #include <boost/geometry/core/cs.hpp>
18 #include <boost/geometry/core/access.hpp>
19 #include <boost/geometry/core/radian_access.hpp>
20
21 #include <boost/geometry/util/math.hpp>
22 #include <boost/geometry/util/promote_floating_point.hpp>
23 #include <boost/geometry/util/select_calculation_type.hpp>
24
25 #include <boost/geometry/strategies/side.hpp>
26 #include <boost/geometry/strategies/spherical/disjoint_segment_box.hpp>
27 #include <boost/geometry/strategies/spherical/envelope_segment.hpp>
28 //#include <boost/geometry/strategies/concepts/side_concept.hpp>
29
30
31 namespace boost { namespace geometry
32 {
33
34
35 namespace strategy { namespace side
36 {
37
38 #ifndef DOXYGEN_NO_DETAIL
39 namespace detail
40 {
41
42 template <typename T>
spherical_side_formula(T const & lambda1,T const & delta1,T const & lambda2,T const & delta2,T const & lambda,T const & delta)43 int spherical_side_formula(T const& lambda1, T const& delta1,
44 T const& lambda2, T const& delta2,
45 T const& lambda, T const& delta)
46 {
47 // Create temporary points (vectors) on unit a sphere
48 T const cos_delta1 = cos(delta1);
49 T const c1x = cos_delta1 * cos(lambda1);
50 T const c1y = cos_delta1 * sin(lambda1);
51 T const c1z = sin(delta1);
52
53 T const cos_delta2 = cos(delta2);
54 T const c2x = cos_delta2 * cos(lambda2);
55 T const c2y = cos_delta2 * sin(lambda2);
56 T const c2z = sin(delta2);
57
58 // (Third point is converted directly)
59 T const cos_delta = cos(delta);
60
61 // Apply the "Spherical Side Formula" as presented on my blog
62 T const dist
63 = (c1y * c2z - c1z * c2y) * cos_delta * cos(lambda)
64 + (c1z * c2x - c1x * c2z) * cos_delta * sin(lambda)
65 + (c1x * c2y - c1y * c2x) * sin(delta);
66
67 T zero = T();
68 return math::equals(dist, zero) ? 0
69 : dist > zero ? 1
70 : -1; // dist < zero
71 }
72
73 }
74 #endif // DOXYGEN_NO_DETAIL
75
76 /*!
77 \brief Check at which side of a Great Circle segment a point lies
78 left of segment (> 0), right of segment (< 0), on segment (0)
79 \ingroup strategies
80 \tparam CalculationType \tparam_calculation
81 */
82 template <typename CalculationType = void>
83 class spherical_side_formula
84 {
85
86 public :
87 typedef strategy::envelope::spherical_segment<CalculationType> envelope_strategy_type;
88
get_envelope_strategy()89 static inline envelope_strategy_type get_envelope_strategy()
90 {
91 return envelope_strategy_type();
92 }
93
94 typedef strategy::disjoint::segment_box_spherical disjoint_strategy_type;
95
get_disjoint_strategy()96 static inline disjoint_strategy_type get_disjoint_strategy()
97 {
98 return disjoint_strategy_type();
99 }
100
101 template <typename P1, typename P2, typename P>
apply(P1 const & p1,P2 const & p2,P const & p)102 static inline int apply(P1 const& p1, P2 const& p2, P const& p)
103 {
104 typedef typename promote_floating_point
105 <
106 typename select_calculation_type_alt
107 <
108 CalculationType,
109 P1, P2, P
110 >::type
111 >::type calculation_type;
112
113 calculation_type const lambda1 = get_as_radian<0>(p1);
114 calculation_type const delta1 = get_as_radian<1>(p1);
115 calculation_type const lambda2 = get_as_radian<0>(p2);
116 calculation_type const delta2 = get_as_radian<1>(p2);
117 calculation_type const lambda = get_as_radian<0>(p);
118 calculation_type const delta = get_as_radian<1>(p);
119
120 return detail::spherical_side_formula(lambda1, delta1,
121 lambda2, delta2,
122 lambda, delta);
123 }
124 };
125
126
127 #ifndef DOXYGEN_NO_STRATEGY_SPECIALIZATIONS
128 namespace services
129 {
130
131 /*template <typename CalculationType>
132 struct default_strategy<spherical_polar_tag, CalculationType>
133 {
134 typedef spherical_side_formula<CalculationType> type;
135 };*/
136
137 template <typename CalculationType>
138 struct default_strategy<spherical_equatorial_tag, CalculationType>
139 {
140 typedef spherical_side_formula<CalculationType> type;
141 };
142
143 template <typename CalculationType>
144 struct default_strategy<geographic_tag, CalculationType>
145 {
146 typedef spherical_side_formula<CalculationType> type;
147 };
148
149 }
150 #endif
151
152 }} // namespace strategy::side
153
154 }} // namespace boost::geometry
155
156
157 #endif // BOOST_GEOMETRY_STRATEGIES_SPHERICAL_SSF_HPP
158