ceph/src/boost/libs/geometry/include/boost/geometry/strategies/agnostic/point_in_poly_oriented_winding.hpp

   1 // Boost.Geometry (aka GGL, Generic Geometry Library)
   2
   3 // Copyright (c) 2011-2012 Barend Gehrels, Amsterdam, the Netherlands.
   4
   5 // Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
   6 // (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.
   7
   8 // Use, modification and distribution is subject to the Boost Software License,
   9 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
  10 // http://www.boost.org/LICENSE_1_0.txt)
  11
  12 #ifndef BOOST_GEOMETRY_STRATEGY_AGNOSTIC_POINT_IN_POLY_ORIENTED_WINDING_HPP
  13 #define BOOST_GEOMETRY_STRATEGY_AGNOSTIC_POINT_IN_POLY_ORIENTED_WINDING_HPP
  14
  15
  16 #include <boost/geometry/core/point_order.hpp>
  17 #include <boost/geometry/util/math.hpp>
  18 #include <boost/geometry/util/select_calculation_type.hpp>
  19
  20 #include <boost/geometry/strategies/side.hpp>
  21 #include <boost/geometry/strategies/within.hpp>
  22
  23
  24 namespace boost { namespace geometry
  25 {
  26
  27 namespace strategy { namespace within
  28 {
  29
  30 /*!
  31 \brief Within detection using winding rule, but checking if enclosing ring is
  32     counter clockwise and, if so, reverses the result
  33 \ingroup strategies
  34 \tparam Point \tparam_point
  35 \tparam Reverse True if parameter should be reversed
  36 \tparam PointOfSegment \tparam_segment_point
  37 \tparam CalculationType \tparam_calculation
  38 \author Barend Gehrels
  39 \note The implementation is inspired by terralib http://www.terralib.org (LGPL)
  40 \note but totally revised afterwards, especially for cases on segments
  41 \note Only dependant on "side", -> agnostic, suitable for spherical/latlong
  42
  43 \qbk{
  44 [heading See also]
  45 [link geometry.reference.algorithms.within.within_3_with_strategy within (with strategy)]
  46 }
  47  */
  48 template
  49 <
  50     bool Reverse,
  51     typename Point,
  52     typename PointOfSegment = Point,
  53     typename CalculationType = void
  54 >
  55 class oriented_winding
  56 {
  57     typedef typename select_calculation_type
  58         <
  59             Point,
  60             PointOfSegment,
  61             CalculationType
  62         >::type calculation_type;
  63
  64
  65     typedef typename strategy::side::services::default_strategy
  66         <
  67             typename cs_tag<Point>::type
  68         >::type strategy_side_type;
  69
  70
  71     /*! subclass to keep state */
  72     class counter
  73     {
  74         int m_count;
  75         bool m_touches;
  76         calculation_type m_sum_area;
  77
  78         inline int code() const
  79         {
  80             return m_touches ? 0 : m_count == 0 ? -1 : 1;
  81         }
  82         inline int clockwise_oriented_code() const
  83         {
  84             return (m_sum_area > 0) ? code() : -code();
  85         }
  86         inline int oriented_code() const
  87         {
  88             return Reverse
  89                 ? -clockwise_oriented_code()
  90                 : clockwise_oriented_code();
  91         }
  92
  93     public :
  94         friend class oriented_winding;
  95
  96         inline counter()
  97             : m_count(0)
  98             , m_touches(false)
  99             , m_sum_area(0)
 100         {}
 101
 102         inline void add_to_area(calculation_type triangle)
 103         {
 104             m_sum_area += triangle;
 105         }
 106
 107     };
 108
 109
 110     template <size_t D>
 111     static inline int check_touch(Point const& point,
 112                 PointOfSegment const& seg1, PointOfSegment const& seg2,
 113                 counter& state)
 114     {
 115         calculation_type const p = get<D>(point);
 116         calculation_type const s1 = get<D>(seg1);
 117         calculation_type const s2 = get<D>(seg2);
 118         if ((s1 <= p && s2 >= p) || (s2 <= p && s1 >= p))
 119         {
 120             state.m_touches = true;
 121         }
 122         return 0;
 123     }
 124
 125
 126     template <size_t D>
 127     static inline int check_segment(Point const& point,
 128                 PointOfSegment const& seg1, PointOfSegment const& seg2,
 129                 counter& state)
 130     {
 131         calculation_type const p = get<D>(point);
 132         calculation_type const s1 = get<D>(seg1);
 133         calculation_type const s2 = get<D>(seg2);
 134
 135
 136         // Check if one of segment endpoints is at same level of point
 137         bool eq1 = math::equals(s1, p);
 138         bool eq2 = math::equals(s2, p);
 139
 140         if (eq1 && eq2)
 141         {
 142             // Both equal p -> segment is horizontal (or vertical for D=0)
 143             // The only thing which has to be done is check if point is ON segment
 144             return check_touch<1 - D>(point, seg1, seg2, state);
 145         }
 146
 147         return
 148               eq1 ? (s2 > p ?  1 : -1)  // Point on level s1, UP/DOWN depending on s2
 149             : eq2 ? (s1 > p ? -1 :  1)  // idem
 150             : s1 < p && s2 > p ?  2     // Point between s1 -> s2 --> UP
 151             : s2 < p && s1 > p ? -2     // Point between s2 -> s1 --> DOWN
 152             : 0;
 153     }
 154
 155
 156
 157
 158 public :
 159
 160     // Typedefs and static methods to fulfill the concept
 161     typedef Point point_type;
 162     typedef PointOfSegment segment_point_type;
 163     typedef counter state_type;
 164
 165     static inline bool apply(Point const& point,
 166                 PointOfSegment const& s1, PointOfSegment const& s2,
 167                 counter& state)
 168     {
 169         state.add_to_area(get<0>(s2) * get<1>(s1) - get<0>(s1) * get<1>(s2));
 170
 171         int count = check_segment<1>(point, s1, s2, state);
 172         if (count != 0)
 173         {
 174             int side = strategy_side_type::apply(s1, s2, point);
 175             if (side == 0)
 176             {
 177                 // Point is lying on segment
 178                 state.m_touches = true;
 179                 state.m_count = 0;
 180                 return false;
 181             }
 182
 183             // Side is NEG for right, POS for left.
 184             // The count is -2 for down, 2 for up (or -1/1)
 185             // Side positive thus means UP and LEFTSIDE or DOWN and RIGHTSIDE
 186             // See accompagnying figure (TODO)
 187             if (side * count > 0)
 188             {
 189                 state.m_count += count;
 190             }
 191         }
 192         return ! state.m_touches;
 193     }
 194
 195     static inline int result(counter const& state)
 196     {
 197         return state.oriented_code();
 198     }
 199 };
 200
 201
 202 }} // namespace strategy::within
 203
 204
 205 }} // namespace boost::geometry
 206
 207
 208 #endif // BOOST_GEOMETRY_STRATEGY_AGNOSTIC_POINT_IN_POLY_ORIENTED_WINDING_HPP