From 040b9ab19484010d8a5732b055420faf462a6ac5 Mon Sep 17 00:00:00 2001
From: Ivan Paden <i.paden@tudelft.nl>
Date: Fri, 18 Aug 2023 20:17:38 +0200
Subject: [PATCH] Add precondition that sizing field and remeshing vpmap must
 be the same

---
 .../CGAL/Polygon_mesh_processing/Adaptive_sizing_field.h      | 4 +++-
 .../CGAL/Polygon_mesh_processing/Uniform_sizing_field.h       | 4 +++-
 .../internal/Isotropic_remeshing/Sizing_field_base.h          | 2 ++
 .../include/CGAL/Polygon_mesh_processing/remesh.h             | 3 +++
 4 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/Adaptive_sizing_field.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/Adaptive_sizing_field.h
index 60b5e3a8855..36f714dab6e 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/Adaptive_sizing_field.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/Adaptive_sizing_field.h
@@ -223,12 +223,14 @@ public:
       return boost::none;
   }
 
-  virtual Point_3 split_placement(const halfedge_descriptor h, const PolygonMesh& pmesh) const
+  Point_3 split_placement(const halfedge_descriptor h, const PolygonMesh& pmesh) const
   {
     return midpoint(get(m_vpmap, target(h, pmesh)),
                     get(m_vpmap, source(h, pmesh)));
   }
 
+  const DefaultVPMap& get_vpmap() const { return m_vpmap; }
+
   void update_sizing_map(const vertex_descriptor v, const PolygonMesh& pmesh)
   {
     // calculating it as the average of two vertices on other ends
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/Uniform_sizing_field.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/Uniform_sizing_field.h
index d22e0079d7f..46ca4c5aced 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/Uniform_sizing_field.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/Uniform_sizing_field.h
@@ -126,12 +126,14 @@ public:
       return boost::none;
   }
 
-  virtual Point_3 split_placement(const halfedge_descriptor h, const PolygonMesh& pmesh) const
+  Point_3 split_placement(const halfedge_descriptor h, const PolygonMesh& pmesh) const
   {
     return midpoint(get(m_vpmap, target(h, pmesh)),
                     get(m_vpmap, source(h, pmesh)));
   }
 
+  const VPMap& get_vpmap() const { return m_vpmap; }
+
 private:
   FT m_sq_short;
   FT m_sq_long;
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Isotropic_remeshing/Sizing_field_base.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Isotropic_remeshing/Sizing_field_base.h
index 81afe3af21f..13661883b2a 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Isotropic_remeshing/Sizing_field_base.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Isotropic_remeshing/Sizing_field_base.h
@@ -53,6 +53,8 @@ public:
                                            const PolygonMesh& pmesh) const = 0;
   virtual Point_3 split_placement(const halfedge_descriptor h, const PolygonMesh& pmesh) const = 0;
 
+  virtual const VPMap& get_vpmap() const = 0;
+
 };
 
 }//end namespace CGAL
diff --git a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/remesh.h b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/remesh.h
index db036a4be6a..a36c3248db1 100644
--- a/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/remesh.h
+++ b/Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/remesh.h
@@ -277,6 +277,9 @@ void isotropic_remeshing(const FaceRange& faces
   }
 #endif
 
+  CGAL_precondition_msg((sizing.get_vpmap()) == vpmap, "Input mesh/vertex point map is not the same as the "
+                                                       "one used for sizing field. Remeshing aborted.");
+
 #ifdef CGAL_PMP_REMESHING_VERBOSE
   t.stop();
   std::cout << "\rRemeshing parameters done ("<< t.time() <<" sec)" << std::endl;