Merge pull request #1208 from aprokop/segment_box_intersection

Add segment-box intersection
arborx · Feb 1, 2025 · 9b7baae · 9b7baae
2 parents 166aba4 + e7fb859
commit 9b7baae
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diff --git a/src/geometry/algorithms/ArborX_Intersects.hpp b/src/geometry/algorithms/ArborX_Intersects.hpp
@@ -476,6 +476,42 @@ struct intersects<SegmentTag, SegmentTag, Segment, Segment>
   }
 };
 
+template <typename Segment, typename Box>
+struct intersects<SegmentTag, BoxTag, Segment, Box>
+{
+  KOKKOS_FUNCTION static constexpr bool apply(Segment const &segment,
+                                              Box const &box)
+  {
+    static_assert(GeometryTraits::dimension_v<Segment> == 2);
+
+    if (Details::intersects(segment.a, box) ||
+        Details::intersects(segment.b, box))
+      return true;
+
+    using Point = std::decay_t<decltype(box.minCorner())>;
+
+    auto const &bottom_left = box.minCorner();
+    auto const &top_right = box.maxCorner();
+    auto const top_left = Point{bottom_left[0], top_right[1]};
+    auto const bottom_right = Point{top_right[0], bottom_left[1]};
+
+    return Details::intersects(segment, Segment{bottom_left, top_left}) ||
+           Details::intersects(segment, Segment{bottom_left, bottom_right}) ||
+           Details::intersects(segment, Segment{top_right, top_left}) ||
+           Details::intersects(segment, Segment{top_right, bottom_right});
+  }
+};
+
+template <typename Box, typename Segment>
+struct intersects<BoxTag, SegmentTag, Box, Segment>
+{
+  KOKKOS_FUNCTION static constexpr bool apply(Box const &box,
+                                              Segment const &segment)
+  {
+    return Details::intersects(segment, box);
+  }
+};
+
 } // namespace Dispatch
 
 } // namespace ArborX::Details

diff --git a/test/tstDetailsAlgorithms.cpp b/test/tstDetailsAlgorithms.cpp
@@ -327,6 +327,20 @@ BOOST_AUTO_TEST_CASE(intersects)
   BOOST_TEST(!intersects(Segment2{{1.1, 1}, {2, 1}}, seg));
   BOOST_TEST(!intersects(Segment2{{1, 0}, {2, 1}}, seg));
   BOOST_TEST(!intersects(Segment2{{1, 3}, {3, 1.1}}, seg));
+
+  constexpr ArborX::Box<2> box2{{{0.0, 0.0}}, {{1.0, 1.0}}};
+  BOOST_TEST(intersects(Segment2{{0, 0}, {0, 0}}, box2));
+  BOOST_TEST(intersects(Segment2{{-1, 1}, {1, -1}}, box2));
+  BOOST_TEST(intersects(Segment2{{-1, 0}, {2, 0}}, box2));
+  BOOST_TEST(intersects(Segment2{{-1, 0.5}, {0.5, 0.5}}, box2));
+  BOOST_TEST(intersects(Segment2{{0.5, 0.5}, {0.5, 2}}, box2));
+  BOOST_TEST(intersects(Segment2{{-1, 2}, {2, -1}}, box2));
+  BOOST_TEST(intersects(Segment2{{0.5, 2}, {0.5, -1}}, box2));
+  BOOST_TEST(intersects(Segment2{{0.4, 0.4}, {0.6, 0.6}}, box2));
+  BOOST_TEST(!intersects(Segment2{{0, -1}, {1, -1}}, box2));
+  BOOST_TEST(!intersects(Segment2{{0.5, 1.6}, {2, 0}}, box2));
+  BOOST_TEST(intersects(box2, Segment2{{-1, 2}, {2, -1}}));
+  BOOST_TEST(!intersects(Segment2{{0.5, 1.6}, {2, 0}}, box2));
 }
 
 BOOST_AUTO_TEST_CASE(equals)