[overlay] fix new case #case_recursive_boxes_48 for self-intersections

by discarding self ii turns NOT located within another geometry

include/boost/geometry/algorithms/detail/overlay/enrich_intersection_points.hpp

@@ -371,7 +371,12 @@ inline void enrich_intersection_points(Turns& turns,
             OverlayType,
             target_operation
         >::apply(turns, geometry1, geometry2);
-//    detail::overlay::discard_open_turns
+    detail::overlay::discard_open_turns
+        <
+            OverlayType,
+            target_operation
+        >::apply(turns, geometry1, geometry2);
+
     // Create a map of vectors of indexed operation-types to be able
     // to sort intersection points PER RING
     mapped_vector_type mapped_vector;

include/boost/geometry/algorithms/detail/overlay/handle_self_turns.hpp

@@ -73,6 +73,66 @@ struct discard_closed_turns<overlay_union, operation_union>
     }
 };
 
+struct discard_self_intersection_turns
+{
+    template <typename Turns, typename Geometry0, typename Geometry1>
+    static inline
+    void apply(Turns& turns,
+            Geometry0 const& geometry0, Geometry1 const& geometry1)
+    {
+        typedef typename boost::range_value<Turns>::type turn_type;
+
+        for (typename boost::range_iterator<Turns>::type
+                it = boost::begin(turns);
+             it != boost::end(turns);
+             ++it)
+        {
+            turn_type& turn = *it;
+
+            if (turn.cluster_id >= 0
+                    || turn.discarded
+                    || ! is_self_turn<overlay_intersection>(turn))
+            {
+                continue;
+            }
+
+            segment_identifier const& id0 = turn.operations[0].seg_id;
+            segment_identifier const& id1 = turn.operations[1].seg_id;
+            if (id0.multi_index != id1.multi_index
+                    || (id0.ring_index == -1 && id1.ring_index == -1)
+                    || (id0.ring_index >= 0 && id1.ring_index >= 0))
+            {
+                // Not an ii ring (int/ext) on same ring
+                continue;
+            }
+
+            // It is a non co-located ii self-turn
+            // Check if it is within the other geometry
+            // If not, it can be ignored
+
+            bool const within =
+                    turn.operations[0].seg_id.source_index == 0
+                    ? geometry::within(turn.point, geometry1)
+                    : geometry::within(turn.point, geometry0);
+
+            if (! within)
+            {
+                // It is not within another geometry, discard the turn
+                turn.discarded = true;
+            }
+        }
+    }
+};
+
+template <overlay_type OverlayType, operation_type OperationType>
+struct discard_open_turns : discard_turns {};
+
+// Handler it for intersection
+template <>
+struct discard_open_turns<overlay_intersection, operation_intersection>
+        : discard_self_intersection_turns {};
+
+// For difference, it should be done in a different way (TODO)
 
 }} // namespace detail::overlay
 #endif //DOXYGEN_NO_DETAIL

test/algorithms/overlay/multi_overlay_cases.hpp

@@ -932,6 +932,12 @@ static std::string case_recursive_boxes_47[2] =
     "MULTIPOLYGON(((4 5,4 4,1 4,1 5,4 5)),((5 6,5 7,6 7,6 6,5 6)),((5 6,5 5,4 5,4 6,5 6)),((5 3,5 5,6 5,6 3,5 3)),((5 3,5 2,4 2,4 3,5 3)),((6 5,6 6,7 6,7 5,6 5)),((3 7,2 7,2 9,3 9,3 8,4 8,4 7,3 7)))"
 };
 
+static std::string case_recursive_boxes_48[2] =
+{
+    "MULTIPOLYGON(((6 7,6 8,7 8,7 7,6 7)))",
+    "MULTIPOLYGON(((9 9,10 9,10 7,9 7,9 5,8 5,8 6,7 6,7 7,6 7,6 8,7 8,7 9,8 9,8 10,9 10,9 9),(9 8,8 8,8 7,9 7,9 8)))"
+};
+
 static std::string pie_21_7_21_0_3[2] =
 {
     "MULTIPOLYGON(((2500 2500,2500 3875,2855 3828,3187 3690,3472 3472,3690 3187,3828 2855,3875 2500,3828 2144,3690 1812,3472 1527,3187 1309,2855 1171,2499 1125,2144 1171,1812 1309,1527 1527,1309 1812,1171 2144,1125 2499,1171 2855,1309 3187,2500 2500)))",

test/algorithms/set_operations/intersection/intersection_multi.cpp

@@ -282,6 +282,7 @@ void test_areal()
     TEST_INTERSECTION(case_recursive_boxes_43, 2, 0, 22.5);
     TEST_INTERSECTION(case_recursive_boxes_44, 2, 0, 3.0);
     TEST_INTERSECTION(case_recursive_boxes_45, 7, 0, 12.0);
+    TEST_INTERSECTION(case_recursive_boxes_48, 1, 0, 1.0);
 
     test_one<Polygon, MultiPolygon, MultiPolygon>("ggl_list_20120915_h2_a",
         ggl_list_20120915_h2[0], ggl_list_20120915_h2[1],