method Triangulation_3<GT,Tds>::triangle returns a triangle oriented

towards the outside of the cell c for facet (c,i)

Packages/Triangulation_3/TODO

@@ -1,8 +1,5 @@
 -------------- POUR LA RELEASE
 
-- .triangle(Facet) devrait retourner un triangle oriente 
-  (cf mail sur cgal-discuss-l).
-
 - bien tester le output_stream de T_3 et le copy_tds (ordre de creation des
   sommets). 
 - Verifier qu'il n'y a pas d'autres operations du meme style a modifier. 

Packages/Triangulation_3/changes.txt

@@ -1,3 +1,7 @@
+Version 1.110 (10 April 02)
+- method Triangulation_3<GT,Tds>::triangle returns a triangle oriented 
+towards the outside of the cell c for facet (c,i)
+
 Version 1.109 (9 April 02)
 - SunPro can't eat the automatic conversion iterator -> handle in some cases,
   so fix example_color.C.

Packages/Triangulation_3/doc_tex/Triangulation_3_ref/Triangulation_3.tex

@@ -218,14 +218,16 @@ an edge (resp. facet) \ccc{infinite} if it is incident to the infinite vertex.
 {Returns the tetrahedron formed by the four vertices of \ccc{c}.
 \ccPrecond{\ccVar.\ccc{dimension()} $=3$ and the cell is finite.}}
 \ccGlue
-\ccMethod{Triangle triangle(const Facet & f) const;}
-{Returns the triangle formed by the three vertices of \ccc{f}. 
-\ccPrecond{\ccVar.\ccc{dimension()} $\geq 2$ and the facet is finite.}}
-\ccGlue
 \ccMethod{Triangle triangle(const Cell_handle c, int i) const;}
-{Same as the previous method for facet \ccc{(c,i)}.
-\ccPrecond{As above and $i \in \{0,1,2,3\}$ in dimension~3, $i = 3$ in
-dimension~2.}}
+{Returns the triangle formed by the three vertices of facet
+\ccc{(c,i)}. The triangle is oriented so that its normal points to the
+outside of cell \ccc{c}. 
+\ccPrecond{\ccVar.\ccc{dimension()} $\geq 2$ and $i \in \{0,1,2,3\}$
+in dimension~3, $i = 3$ in dimension~2, and the facet is finite.}}
+\ccGlue
+\ccMethod{Triangle triangle(const Facet & f) const;}
+{Same as the previous method for facet \ccc{f}. 
+\ccPrecond{\ccVar.\ccc{dimension()} $\geq 2$ and the facet is finite.}}
 \ccGlue
 \ccMethod{Segment segment(const Edge & e) const;}
 {Returns the line segment formed by the vertices of \ccc{e}.

Packages/Triangulation_3/doc_tex/basic/Triangulation_3_ref/Triangulation_3.tex

@@ -218,14 +218,16 @@ an edge (resp. facet) \ccc{infinite} if it is incident to the infinite vertex.
 {Returns the tetrahedron formed by the four vertices of \ccc{c}.
 \ccPrecond{\ccVar.\ccc{dimension()} $=3$ and the cell is finite.}}
 \ccGlue
-\ccMethod{Triangle triangle(const Facet & f) const;}
-{Returns the triangle formed by the three vertices of \ccc{f}. 
-\ccPrecond{\ccVar.\ccc{dimension()} $\geq 2$ and the facet is finite.}}
-\ccGlue
 \ccMethod{Triangle triangle(const Cell_handle c, int i) const;}
-{Same as the previous method for facet \ccc{(c,i)}.
-\ccPrecond{As above and $i \in \{0,1,2,3\}$ in dimension~3, $i = 3$ in
-dimension~2.}}
+{Returns the triangle formed by the three vertices of facet
+\ccc{(c,i)}. The triangle is oriented so that its normal points to the
+outside of cell \ccc{c}. 
+\ccPrecond{\ccVar.\ccc{dimension()} $\geq 2$ and $i \in \{0,1,2,3\}$
+in dimension~3, $i = 3$ in dimension~2, and the facet is finite.}}
+\ccGlue
+\ccMethod{Triangle triangle(const Facet & f) const;}
+{Same as the previous method for facet \ccc{f}. 
+\ccPrecond{\ccVar.\ccc{dimension()} $\geq 2$ and the facet is finite.}}
 \ccGlue
 \ccMethod{Segment segment(const Edge & e) const;}
 {Returns the line segment formed by the vertices of \ccc{e}.

Packages/Triangulation_3/include/CGAL/Triangulation_3.h

@@ -99,8 +99,9 @@ public:
                                                Finite_vertices_iterator_base;
   typedef Triangulation_iterator_handle_adaptor_3<Finite_cells_iterator_base,
                                Cell_handle>    Finite_cells_iterator;
-  typedef Triangulation_iterator_handle_adaptor_3<Finite_vertices_iterator_base,
-                               Vertex_handle>  Finite_vertices_iterator;
+  typedef Triangulation_iterator_handle_adaptor_3
+                               <Finite_vertices_iterator_base,
+				 Vertex_handle> Finite_vertices_iterator;
   typedef Filter_iterator<Edge_iterator, Infinite_tester>
                                                Finite_edges_iterator;
   typedef Filter_iterator<Facet_iterator, Infinite_tester>
@@ -1193,11 +1194,15 @@ triangle(const Cell_handle c, int i) const
 { 
   CGAL_triangulation_precondition( dimension() == 2 || dimension() == 3 );
   CGAL_triangulation_precondition( (dimension() == 2 && i == 3)
-				   || (dimension() == 3 && i >= 0 && i <= 3) );
+				|| (dimension() == 3 && i >= 0 && i <= 3) );
   CGAL_triangulation_precondition( ! is_infinite(Facet(c, i)) );
-  return construct_triangle(c->vertex(i<=0 ? 1 : 0)->point(),
-			    c->vertex(i<=1 ? 2 : 1)->point(),
-			    c->vertex(i<=2 ? 3 : 2)->point());
+  if ( (i&1)==0 ) 
+    return construct_triangle(c->vertex( (i+2)&3 )->point(),
+			      c->vertex( (i+1)&3 )->point(),
+			      c->vertex( (i+3)&3 )->point());
+  return construct_triangle(c->vertex( (i+1)&3 )->point(),
+			    c->vertex( (i+2)&3 )->point(),
+			    c->vertex( (i+3)&3 )->point());
 }
 
 template < class GT, class Tds >