- Add a new TCellBase model Triangulation_cell_base_with_circumcenter_3,

which stores the circumcenter.
- Delaunay.dual() now calls the .circumcenter() function of the cell
  to retrieve it.
- It implies a new requirement on the TCellBase, for the Delaunay::dual()
  case, hence the default model T_cell_base_3 provides a new function
  (and the concept is updated).

Triangulation_3/demo/Triangulation_3/demo_voronoi.cpp

@@ -33,6 +33,7 @@ int main()
 #include <CGAL/Exact_predicates_exact_constructions_kernel.h>
 
 #include <CGAL/Delaunay_triangulation_3.h>
+#include <CGAL/Triangulation_cell_base_with_circumcenter_3.h>
 
 #include <CGAL/IO/Triangulation_geomview_ostream_3.h>
 
@@ -42,7 +43,11 @@ int main()
 // demo, not only predicates 
 typedef CGAL::Exact_predicates_exact_constructions_kernel K;
 
-typedef CGAL::Delaunay_triangulation_3<K> Triangulation;
+typedef CGAL::Triangulation_vertex_base_3<K>                 Vb;
+typedef CGAL::Triangulation_cell_base_with_circumcenter_3<K> Cb;
+typedef CGAL::Triangulation_data_structure_3<Vb, Cb>         TDS;
+typedef CGAL::Delaunay_triangulation_3<K, TDS>               Triangulation;
+// typedef CGAL::Delaunay_triangulation_3<K> Triangulation;
 
 typedef Triangulation::Point          Point;
 

Triangulation_3/demo/Triangulation_3/makefile

@@ -13,6 +13,7 @@ include $(CGAL_MAKEFILE)
 #---------------------------------------------------------------------#
 
 CXXFLAGS = \
+           -I$(HOME)/CGAL/trunk/Kernel_23/include \
            -I../../include \
            $(TESTSUITE_CXXFLAGS) \
            $(EXTRA_FLAGS) \

Triangulation_3/doc_tex/Triangulation_3_ref/TriangulationCellBase_3.tex

@@ -15,17 +15,26 @@
 
 \ccDefinition
 
-The cell base required by the geometric triangulations does not store any
+The cell base required by the basic triangulation does not need to store any
 geometric information, so only the requirements of the triangulation data
-structure apply.  However, we provide this concept for symmetry with the
-vertex case.
+structure apply.
+
+However, for the Delaunay triangulation, the ability to store the circumcenter
+is provided (for optimization reasons), hence an additional requirement only
+in this case, and only when the dual functions are called.
 
 \ccRefines \ccc{TriangulationDSCellBase_3}
 
+\ccMethod{const DelaunayTriangulationTraits_3::Point_3& circumcenter(
+  const DelaunayTriangulationTraits_3&gt = DelaunayTriangulationTraits_3()) const;}
+{Returns the circumcenter.}
+
+
 \ccHasModels
 
 \ccc{CGAL::Triangulation_cell_base_3}\\
 \ccc{CGAL::Triangulation_cell_base_with_info_3}
+\ccc{CGAL::Triangulation_cell_base_with_circumcenter_3}
 
 \ccSeeAlso
 

Triangulation_3/doc_tex/Triangulation_3_ref/Triangulation_cell_base_3.tex

@@ -33,6 +33,12 @@ The second template argument is a combinatorial cell base class from which
 \ccc{Triangulation_cell_base_3} derives.
 It has the default value \ccc{Triangulation_ds_cell_base_3<>}.
 
+Note that this model does not store the circumcenter, but computes it
+every time the circumcenter function is called.  See
+\ccc{CGAL::Triangulation_cell_base_with_circumcenter_3} for a way to cache the
+circumcenter computation.
+
+
 \ccIsModel \ccc{TriangulationCellBase_3}
 
 \ccInheritsFrom \ccc{TriangulationDSCellBase_3}
@@ -41,6 +47,7 @@ It has the default value \ccc{Triangulation_ds_cell_base_3<>}.
 
 \ccc{CGAL::Triangulation_ds_cell_base_3}\\
 \ccc{CGAL::Triangulation_cell_base_with_info_3}\\
+\ccc{CGAL::Triangulation_cell_base_with_circumcenter_3}\\
 \ccc{CGAL::Triangulation_vertex_base_3}
 
 \end{ccRefClass}

Triangulation_3/doc_tex/Triangulation_3_ref/Triangulation_cell_base_with_circumcenter_3.tex

@@ -0,0 +1,61 @@
+% +------------------------------------------------------------------------+
+% | Reference manual page: Triangulation_cell_base_with_circumcenter_3.tex
+% +------------------------------------------------------------------------+
+% | 29.3.2000   Sylvain Pion
+% | Package: Triangulation3
+% | 
+\RCSdef{\RCSTriangulationcellbaseRev}{$Id$}
+\RCSdefDate{\RCSTriangulationcellbaseDate}{$Date$}
+% |
+%%RefPage: end of header, begin of main body
+% +------------------------------------------------------------------------+
+
+
+\begin{ccRefClass}{Triangulation_cell_base_with_circumcenter_3<DelaunayTriangulationTraits_3, TriangulationCellBase_3>}
+
+\ccDefinition
+
+The class \ccc{Triangulation_cell_base_with_circumcenter_3} is a model of the
+concept \ccc{TriangulationCellBase_3}, the base cell of a 3D-triangulation.
+It provides an easy way to cache the computation of the circumcenter of
+tetrahedra.
+Note that input/output operators discard this additional information.
+
+All functions modifying the vertices of the cell, invalidate the cached
+circumcenter.
+
+\ccInclude{CGAL/Triangulation_cell_base_with_circumcenter_3.h}
+
+\ccParameters
+
+The first template argument is the geometric traits class
+\ccc{DelaunayTriangulationTraits_3}.
+
+The second template argument is a cell base class from which
+\ccc{Triangulation_cell_base_with_circumcenter_3} derives.
+It has the default value \ccc{Triangulation_cell_base_3<DelaunayTriangulationTraits_3>}.
+
+\ccIsModel \ccc{TriangulationCellBase_3}
+
+\ccInheritsFrom \ccc{TriangulationCellBase_3}
+
+%\ccTypes
+%\ccTypedef{typedef Info Info;}{}
+
+\ccCreationVariable{v}
+
+\ccAccessFunctions
+\ccThree{const Info&}{Facetxxxxxxxx}{}
+\ccTagFullDeclarations
+
+\ccMethod{const DelaunayTriangulationTraits_3::Point_3& circumcenter(
+  const DelaunayTriangulationTraits_3&gt = DelaunayTriangulationTraits_3()) const;}
+{Computes the circumcenter of the tetrahedron, or retrieve it if already
+computed.}
+
+\ccSeeAlso
+
+\ccc{CGAL::Triangulation_cell_base_3}\\
+\ccc{CGAL::Triangulation_cell_base_with_info_3}
+
+\end{ccRefClass}

Triangulation_3/doc_tex/Triangulation_3_ref/Triangulation_cell_base_with_info_3.tex

@@ -56,6 +56,7 @@ The third template argument is a cell base class from which
 \ccSeeAlso
 
 \ccc{CGAL::Triangulation_cell_base_3}\\
+\ccc{CGAL::Triangulation_cell_base_with_circumcenter_3}
 \ccc{CGAL::Triangulation_vertex_base_with_info_3}
 
 \end{ccRefClass}

Triangulation_3/doc_tex/Triangulation_3_ref/intro.tex

@@ -78,6 +78,7 @@ Figure~\ref{Triangulation3-fig-orient}.
 
 \ccRefIdfierPage{CGAL::Triangulation_cell_base_3<TriangulationTraits_3, TriangulationDSCellBase_3>}\\
 \ccRefIdfierPage{CGAL::Triangulation_cell_base_with_info_3<Info, TriangulationTraits_3, TriangulationCellBase_3>}\\
+\ccRefIdfierPage{CGAL::Triangulation_cell_base_with_circumcenter_3<DelaunayTriangulationTraits_3, TriangulationCellBase_3>}\\
 \ccRefIdfierPage{CGAL::Triangulation_vertex_base_3<TriangulationTraits_3, TriangulationDSVertexBase_3>}\\
 \ccRefIdfierPage{CGAL::Triangulation_vertex_base_with_info_3<Info, TriangulationTraits_3, TriangulationVertexBase_3>}\\
 \ccRefIdfierPage{CGAL::Triangulation_hierarchy_vertex_base_3<TriangulationVertexBase_3>}\\

Triangulation_3/doc_tex/Triangulation_3_ref/main.tex

@@ -27,6 +27,7 @@
 
 \input{Triangulation_3_ref/Triangulation_cell_base_3.tex}
 \input{Triangulation_3_ref/Triangulation_cell_base_with_info_3.tex}
+\input{Triangulation_3_ref/Triangulation_cell_base_with_circumcenter_3.tex}
 \input{Triangulation_3_ref/Triangulation_vertex_base_3.tex}
 \input{Triangulation_3_ref/Triangulation_vertex_base_with_info_3.tex}
 \input{Triangulation_3_ref/Triangulation_hierarchy_vertex_base_3.tex}

Triangulation_3/include/CGAL/Delaunay_triangulation_3.h

@@ -134,13 +134,6 @@ protected:
       return geom_traits().construct_circumcenter_3_object()(p, q, r);
   }
 
-  Point
-  construct_circumcenter(const Point &p, const Point &q,
-	                 const Point &r, const Point &s) const
-  {
-      return geom_traits().construct_circumcenter_3_object()(p, q, r, s);
-  }
-
   Line
   construct_equi_distant_line(const Point &p1, const Point &p2,
                               const Point &p3) const
@@ -1388,10 +1381,7 @@ dual(Cell_handle c) const
 {
   CGAL_triangulation_precondition(dimension()==3);
   CGAL_triangulation_precondition( ! is_infinite(c) );
-  return construct_circumcenter( c->vertex(0)->point(),
-				 c->vertex(1)->point(),
-				 c->vertex(2)->point(),
-				 c->vertex(3)->point() );
+  return c->circumcenter(geom_traits());
 }
 
 

Triangulation_3/include/CGAL/Triangulation_cell_base_3.h

@@ -1,4 +1,3 @@
-
 // Copyright (c) 1999  INRIA Sophia-Antipolis (France).
 // All rights reserved.
 //
@@ -17,6 +16,7 @@
 // 
 //
 // Author(s)     : Monique Teillaud <Monique.Teillaud@sophia.inria.fr>
+//                 Sylvain Pion
 
 // cell of a triangulation of any dimension <=3
 
@@ -67,6 +67,16 @@ public:
   Point_iterator hidden_points_begin() const { return hidden_points_end(); }
   Point_iterator hidden_points_end() const { return NULL; }
   void hide_point (const Point &p) const { }
+
+  typename Geom_traits::Point_3
+  circumcenter(const Geom_traits& gt = Geom_traits()) const
+  {
+      return gt.construct_circumcenter_3_object()(this->vertex(0)->point(),
+                                                  this->vertex(1)->point(),
+                                                  this->vertex(2)->point(),
+                                                  this->vertex(3)->point());
+  }
+
 };
 
 // The following should be useless.

Triangulation_3/include/CGAL/Triangulation_cell_base_with_circumcenter_3.h

@@ -0,0 +1,137 @@
+// Copyright (c) 1999-2006  INRIA Sophia-Antipolis (France).
+// All rights reserved.
+//
+// This file is part of CGAL (www.cgal.org); you may redistribute it under
+// the terms of the Q Public License version 1.0.
+// See the file LICENSE.QPL distributed with CGAL.
+//
+// Licensees holding a valid commercial license may use this file in
+// accordance with the commercial license agreement provided with the software.
+//
+// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
+// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+//
+// $Source: /CVSROOT/CGAL/Packages/Triangulation_3/include/CGAL/Triangulation_cell_base_3.h,v $
+// $Revision$ $Date$
+// $Name:  $
+//
+// Author(s)     : Monique Teillaud <Monique.Teillaud@sophia.inria.fr>
+//                 Sylvain Pion
+
+// cell of a triangulation of any dimension <=3,
+// storing its circumcenter lazily.
+
+#ifndef CGAL_TRIANGULATION_CELL_BASE_WITH_CIRCUMCENTER_3_H
+#define CGAL_TRIANGULATION_CELL_BASE_WITH_CIRCUMCENTER_3_H
+
+#include <CGAL/basic.h>
+#include <CGAL/triangulation_assertions.h>
+#include <CGAL/Triangulation_short_names_3.h>
+#include <CGAL/Triangulation_ds_cell_base_3.h>
+
+CGAL_BEGIN_NAMESPACE
+
+template < typename GT, typename Cb = Triangulation_ds_cell_base_3<> >
+class Triangulation_cell_base_with_circumcenter_3
+  : public Cb
+{
+  typedef typename GT::Point_3                         Point_3;
+
+  mutable Point_3 * circumcenter_;
+
+  void invalidate_circumcenter()
+  {
+      if (circumcenter_) {
+          delete circumcenter_;
+          circumcenter_ = NULL;
+      }
+  }
+
+public:
+  typedef typename Cb::Vertex_handle                   Vertex_handle;
+  typedef typename Cb::Cell_handle                     Cell_handle;
+
+  typedef GT                                           Geom_traits;
+
+  template < typename TDS2 >
+  struct Rebind_TDS {
+    typedef typename Cb::template Rebind_TDS<TDS2>::Other         Cb2;
+    typedef Triangulation_cell_base_with_circumcenter_3<GT, Cb2>  Other;
+  };
+
+  Triangulation_cell_base_with_circumcenter_3()
+    : Cb(), circumcenter_(NULL) {}
+
+  Triangulation_cell_base_with_circumcenter_3
+        (const Triangulation_cell_base_with_circumcenter_3 &c)
+  {
+      if (c.circumcenter_ != NULL)
+	  circumcenter_ = new Point_3(*circumcenter_);
+      else
+          circumcenter_ = NULL;
+  }
+
+  Triangulation_cell_base_with_circumcenter_3&
+  operator=(const Triangulation_cell_base_with_circumcenter_3 &c)
+  {
+      Triangulation_cell_base_with_circumcenter_3 tmp=c;
+      std::swap(tmp, *this);
+      return *this;
+  }
+
+  Triangulation_cell_base_with_circumcenter_3(
+	                    const Vertex_handle& v0, const Vertex_handle& v1,
+                            const Vertex_handle& v2, const Vertex_handle& v3)
+    : Cb(v0, v1, v2, v3), circumcenter_(NULL) {}
+
+  Triangulation_cell_base_with_circumcenter_3(
+	                    const Vertex_handle& v0, const Vertex_handle& v1,
+                            const Vertex_handle& v2, const Vertex_handle& v3,
+                            const Cell_handle&   n0, const Cell_handle&   n1,
+                            const Cell_handle&   n2, const Cell_handle&   n3)
+    : Cb(v0, v1, v2, v3, n0, n1, n2, n3), circumcenter_(NULL) {}
+
+  ~Triangulation_cell_base_with_circumcenter_3()
+  {
+      delete circumcenter_;
+  }
+
+  // We must override the functions that modify the vertices.
+  // And if the point inside a vertex is modified, we fail,
+  // but there's not much we can do for this now.
+  void set_vertex(int i, const Vertex_handle& v)
+  {
+      invalidate_circumcenter();
+      Cb::set_vertex(i, v);
+  }
+
+  void set_vertices()
+  {
+      invalidate_circumcenter();
+      Cb::set_vertices();
+  }
+
+  void set_vertices(const Vertex_handle& v0, const Vertex_handle& v1,
+                    const Vertex_handle& v2, const Vertex_handle& v3)
+  {
+      invalidate_circumcenter();
+      Cb::set_vertices(v0, v1, v2, v3);
+  }
+
+  const Point_3 &
+  circumcenter(const Geom_traits& gt = Geom_traits()) const
+  {
+      if (circumcenter_ == NULL) {
+	  circumcenter_ = new Point_3(
+	      gt.construct_circumcenter_3_object()(this->vertex(0)->point(),
+	                                           this->vertex(1)->point(),
+						   this->vertex(2)->point(),
+						   this->vertex(3)->point()));
+      }
+      return *circumcenter_;
+  }
+};
+
+CGAL_END_NAMESPACE
+
+#endif // CGAL_TRIANGULATION_CELL_BASE_WITH_CIRCUMCENTER_3_H

Triangulation_3/test/Triangulation_3/Makefile

@@ -15,7 +15,7 @@ include $(CGAL_MAKEFILE)
 
 CXXFLAGS = \
            -I../../include \
-           -I../../../Kernel_23/include \
+           -I$(HOME)/CGAL/trunk/Kernel_23/include \
            $(TESTSUITE_CXXFLAGS) \
            $(EXTRA_FLAGS) \
            $(CGAL_CXXFLAGS) \

Triangulation_3/test/Triangulation_3/test_delaunay_3.C

@@ -18,6 +18,7 @@
 // Author(s)     : Francois Rebufat
 
 #include <CGAL/Delaunay_triangulation_3.h>
+#include <CGAL/Triangulation_cell_base_with_circumcenter_3.h>
 
 bool del=true;
 
@@ -30,6 +31,14 @@ int main()
 
   _test_cls_delaunay_3( Cls() );
 
+  // Second version for the circumcenter storing cell base class.
+  typedef CGAL::Triangulation_vertex_base_3<K>                 Vb;
+  typedef CGAL::Triangulation_cell_base_with_circumcenter_3<K> Cb;
+  typedef CGAL::Triangulation_data_structure_3<Vb, Cb>         TDS;
+  typedef CGAL::Delaunay_triangulation_3<K, TDS>               Cls_circumcenter;
+
+  _test_cls_delaunay_3( Cls_circumcenter() );
+
   return 0;
 }