From 25105714486143362edb1ec0a70ee98b6c0d6b89 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Loriot?= <sebastien.loriot@cgal.org>
Date: Thu, 4 Feb 2021 16:26:47 +0100
Subject: [PATCH 1/2] always init faces of patches

---
 .../internal/Corefinement/face_graph_utils.h  | 28 ++++++++++---------
 1 file changed, 15 insertions(+), 13 deletions(-)

diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Corefinement/face_graph_utils.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Corefinement/face_graph_utils.h
index c188231238c..c15a4f60ef6 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Corefinement/face_graph_utils.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Corefinement/face_graph_utils.h
@@ -437,22 +437,18 @@ void extract_patch_simplices(
   typedef typename GT::vertex_descriptor vertex_descriptor;
   typedef typename GT::face_descriptor face_descriptor;
 
-  for(face_descriptor f : faces(pm))
+  for(face_descriptor f : patch_faces)
   {
-    if ( patch_ids[ get(fids, f) ]==patch_id )
+    for(halfedge_descriptor h :
+                  halfedges_around_face(halfedge(f, pm),pm))
     {
-      patch_faces.push_back( f );
-      for(halfedge_descriptor h :
-                    halfedges_around_face(halfedge(f, pm),pm))
+      if ( !is_intersection_edge.count(edge(h, pm)) )
       {
-        if ( !is_intersection_edge.count(edge(h, pm)) )
-        {
-          if ( h < opposite(h,pm) || is_border(opposite(h,pm),pm) )
-            interior_edges.push_back( h );
-        }
-        else
-          shared_edges.push_back(h);
+        if ( h < opposite(h,pm) || is_border(opposite(h,pm),pm) )
+          interior_edges.push_back( h );
       }
+      else
+        shared_edges.push_back(h);
     }
   }
 
@@ -494,7 +490,13 @@ struct Patch_container{
     , patch_ids(patch_ids)
     , fids(fids)
     , is_intersection_edge(is_intersection_edge)
-  {}
+  {
+    typedef boost::graph_traits<PolygonMesh> GT;
+    typedef typename GT::face_descriptor face_descriptor;
+
+    for(face_descriptor f : faces(pm))
+      patches[patch_ids[ get(fids, f) ]].faces.push_back( f );
+  }
 
   Patch_description<PolygonMesh>& operator[](std::size_t i) {
     if ( !patches[i].is_initialized )

From b5277495e2b1111be2cea1cf7327c700fda776d2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Loriot?= <sebastien.loriot@cgal.org>
Date: Fri, 19 Feb 2021 16:10:32 +0100
Subject: [PATCH 2/2] remove no longer needed variables

---
 .../internal/Corefinement/face_graph_utils.h              | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Corefinement/face_graph_utils.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Corefinement/face_graph_utils.h
index c15a4f60ef6..d17227966f0 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Corefinement/face_graph_utils.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Corefinement/face_graph_utils.h
@@ -420,12 +420,9 @@ struct Patch_description{
 // shared_edges will be filled by halfedges pointing in the patch
 // that are inside `is_intersection_edge`, thus mesh boundary halfedges
 // are not necessarily inside.
-template <class PolygonMesh, class FaceIndexMap, class IsIntersectionEdge>
+template <class PolygonMesh, class IsIntersectionEdge>
 void extract_patch_simplices(
-  std::size_t patch_id,
   PolygonMesh& pm,
-  const FaceIndexMap fids,
-  const std::vector<std::size_t>& patch_ids,
   std::vector<typename boost::graph_traits<PolygonMesh>::face_descriptor>& patch_faces,
   std::set<typename boost::graph_traits<PolygonMesh>::vertex_descriptor>& interior_vertices,
   std::vector<typename boost::graph_traits<PolygonMesh>::halfedge_descriptor>& interior_edges,
@@ -502,8 +499,7 @@ struct Patch_container{
     if ( !patches[i].is_initialized )
     {
       extract_patch_simplices(
-        i, pm,
-        fids, patch_ids,
+        pm,
         patches[i].faces, patches[i].interior_vertices,
         patches[i].interior_edges, patches[i].shared_edges,
         is_intersection_edge