GSoC 2025: Hexahedral Mesh Generation

Combinatorial_map/include/CGAL/Combinatorial_map/internal/cmap_3close_cc.h

@@ -0,0 +1,63 @@
+// Copyright (c) 2025 CNRS and LIRIS' Establishments (France).
+// All rights reserved.
+//
+// This file is part of CGAL (www.cgal.org)
+//
+// $URL$
+// $Id$
+// SPDX-License-Identifier: LGPL-3.0-or-later OR LicenseRef-Commercial
+//
+// Author(s)     : Guillaume Damiand <guillaume.damiand@liris.cnrs.fr>
+//
+////////////////////////////////////////////////////////////////////////////////
+#ifndef CGAL_CMAP_3CLOSE_CC_H
+#define CGAL_CMAP_3CLOSE_CC_H
+
+#include <cstddef>
+
+namespace CGAL::internal
+{
+////////////////////////////////////////////////////////////////////////////////
+/** 3-close a connected component
+ *  @param dh a dart
+ *  @return the number of new darts.
+ */
+template<typename LCC>
+std::size_t close_cc_for_beta3(LCC& lcc, typename LCC::Dart_descriptor dh)
+{
+  std::size_t res=0;
+  typename LCC::Dart_descriptor d, d2;
+
+  for (auto it=lcc.template darts_of_cell<3>(dh).begin(),
+       itend=lcc.template darts_of_cell<3>(dh).end(); it!=itend; ++it)
+  {
+    if(lcc.template is_free<3>(it))
+    {
+      d=lcc.create_dart();
+      ++res;
+      lcc.template link_beta_for_involution<3>(it, d);
+
+      // Special cases for 0 and 1
+      if (!lcc.template is_free<1>(it) &&
+          !lcc.template is_free<3>(lcc.template beta<1>(it)))
+      { lcc.template link_beta<1>(lcc.template beta<1,3>(it),d); }
+      if (!lcc.template is_free<0>(it) &&
+          !lcc.template is_free<3>(lcc.template beta<0>(it)))
+      { lcc.template link_beta<0>(lcc.template beta<0,3>(it),d); }
+
+      d2=lcc.template beta<2>(it);
+      while (d2!=lcc.null_dart_descriptor &&
+             !lcc.template is_free<2>(lcc.template beta<3>(d2)))
+      { d2=lcc.template beta<3, 2>(d2); }
+      if (d2!=lcc.null_dart_descriptor && !lcc.template is_free<3>(d2))
+      {
+        lcc.template basic_link_beta_for_involution<2>
+            (lcc.template beta<3>(d2), d);
+      }
+    }
+  }
+  return res;
+}
+////////////////////////////////////////////////////////////////////////////////
+}
+#endif // CGAL_CMAP_3CLOSE_CC_H