From d4fa45f376461dfad835d84adedbbb6249eeeb0a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Loriot?= <sebastien.loriot@cgal.org>
Date: Mon, 3 Mar 2025 20:43:54 +0100
Subject: [PATCH] add test from the issue

---
 .../Polygon_mesh_processing/CMakeLists.txt    |   1 +
 .../Polygon_mesh_processing/issue_8730.cpp    | 145 ++++++++++++++++++
 2 files changed, 146 insertions(+)
 create mode 100644 Polygon_mesh_processing/test/Polygon_mesh_processing/issue_8730.cpp

diff --git a/Polygon_mesh_processing/test/Polygon_mesh_processing/CMakeLists.txt b/Polygon_mesh_processing/test/Polygon_mesh_processing/CMakeLists.txt
index 5f95e3eb196..78fbd76a744 100644
--- a/Polygon_mesh_processing/test/Polygon_mesh_processing/CMakeLists.txt
+++ b/Polygon_mesh_processing/test/Polygon_mesh_processing/CMakeLists.txt
@@ -66,6 +66,7 @@ create_single_source_cgal_program("test_pmp_polyhedral_envelope.cpp")
 create_single_source_cgal_program("test_pmp_np_function.cpp")
 create_single_source_cgal_program("test_degenerate_pmp_clip_split_corefine.cpp")
 create_single_source_cgal_program("test_corefinement_cavities.cpp")
+create_single_source_cgal_program("issue_8730.cpp")
 #  create_single_source_cgal_program("test_pmp_repair_self_intersections.cpp")
 
 find_package(Eigen3 3.2.0 QUIET) #(requires 3.2.0 or greater)
diff --git a/Polygon_mesh_processing/test/Polygon_mesh_processing/issue_8730.cpp b/Polygon_mesh_processing/test/Polygon_mesh_processing/issue_8730.cpp
new file mode 100644
index 00000000000..5ec9cf0898c
--- /dev/null
+++ b/Polygon_mesh_processing/test/Polygon_mesh_processing/issue_8730.cpp
@@ -0,0 +1,145 @@
+#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
+#include <CGAL/Surface_mesh.h>
+#include <CGAL/Polygon_mesh_processing/detect_features.h>
+
+using Kernel = CGAL::Exact_predicates_inexact_constructions_kernel;
+using Point_3 = Kernel::Point_3;
+
+using Surface_mesh = CGAL::Surface_mesh<Point_3>;
+
+using vertex_index = Surface_mesh::vertex_index;
+using halfedge_index = Surface_mesh::halfedge_index;
+using face_index = Surface_mesh::face_index;
+using edge_index = Surface_mesh::edge_index;
+
+
+std::vector<Point_3> points = {
+    {0,0,0},
+    {0,0.5,0},
+    {0,1,0},
+    {0.5,0,0},
+    {0.5,0.5,0},
+    {0.5,1,0},
+    {1,0,0},
+    {1,0.5,0},
+    {1,1,0},
+    {0,0,0.5},
+    {0,0.5,0.5},
+    {0,1,0.5},
+    {0.5,0,0.5},
+    {0.5,1,0.5},
+    {1,0,0.5},
+    {1,0.5,0.5},
+    {1,1,0.5},
+    {0,0,1},
+    {0,0.5,1},
+    {0,1,1},
+    {0.5,0,1},
+    {0.5,0.5,1},
+    {0.5,1,1},
+    {1,0,1},
+    {1,0.5,1},
+    {1,1,1}
+};
+
+std::vector<std::array<int, 3>> faces = {
+    {7,4,5},
+    {7,6,4},
+    {7,5,8},
+    {4,2,5},
+    {2,4,1},
+    {11,5,2},
+    {11,13,5},
+    {11,2,10},
+    {2,1,10},
+    {11,10,18},
+    {11,18,19},
+    {10,17,18},
+    {10,9,17},
+    {20,18,17},
+    {20,21,18},
+    {12,20,17},
+    {12,14,20},
+    {12,17,9},
+    {3,12,9},
+    {3,6,12},
+    {3,9,0},
+    {3,0,1},
+    {9,1,0},
+    {1,9,10},
+    {3,1,4},
+    {6,3,4},
+    {12,6,14},
+    {6,7,14},
+    {15,14,7},
+    {14,15,23},
+    {15,7,8},
+    {15,8,16},
+    {24,15,16},
+    {16,8,13},
+    {22,16,13},
+    {13,8,5},
+    {22,25,16},
+    {22,13,19},
+    {13,11,19},
+    {22,19,21},
+    {21,24,22},
+    {19,18,21},
+    {21,23,24},
+    {22,24,25},
+    {24,16,25},
+    {23,21,20},
+    {24,23,15},
+    {14,23,20}
+};
+
+int main()
+{
+  Surface_mesh mesh;
+  std::vector<vertex_index> vertices(points.size());
+  for (size_t i = 0; i < points.size(); ++i)
+  {
+    vertices[i] = mesh.add_vertex(points[i]);
+  }
+
+  for (size_t i = 0; i < faces.size(); ++i)
+  {
+    vertex_index v0 = vertices[faces[i][0]];
+    vertex_index v1 = vertices[faces[i][1]];
+    vertex_index v2 = vertices[faces[i][2]];
+    mesh.add_face(v0, v1, v2);
+  }
+
+  auto vertexToPatches = mesh.add_property_map<vertex_index, std::set<size_t>>("v:patches").first;
+  auto faceToPatch = mesh.add_property_map<face_index, size_t>("f:patch", std::numeric_limits<size_t>::max()).first;
+  auto edgeToIsFeature = mesh.add_property_map<edge_index, bool>("e:is_feature", false).first;
+
+  double angle_in_deg = 90;
+
+  CGAL::Polygon_mesh_processing::detect_sharp_edges(mesh, angle_in_deg, edgeToIsFeature);
+
+  auto number_of_patches = CGAL::Polygon_mesh_processing::
+    connected_components(mesh, faceToPatch,
+      CGAL::parameters::edge_is_constrained_map(edgeToIsFeature));
+
+  assert(number_of_patches==6);
+
+  CGAL::Polygon_mesh_processing::detect_vertex_incident_patches(mesh,
+    faceToPatch, vertexToPatches, edgeToIsFeature);
+
+  std::array<int,4> degrees = CGAL::make_array(0,0,0,0);
+
+  for (auto v : mesh.vertices())
+  {
+    auto d = vertexToPatches[v].size();
+    assert(d<4);
+    degrees[d]+=1;
+  }
+
+  assert(degrees[0]==6);
+  assert(degrees[1]==0);
+  assert(degrees[2]==12);
+  assert(degrees[3]==8);
+
+  return 0;
+}
\ No newline at end of file