add a random generator on edges of a mesh

Generator/include/CGAL/point_generators_3.h

@@ -271,8 +271,24 @@ public:
                                                          (std::max)(to_double(p.z()), to_double(q.z()))),
                                   rnd) , _p(p), _q(q)
     {
-        generate_point();
+      generate_point();
     }
+
+    template <class Segment_3>
+    Random_points_on_segment_3( const Segment_3& s,
+                                Random& rnd = CGAL::get_default_random())
+        // g is an input iterator creating points of type `P' uniformly
+        // distributed on the segment from p to q except q, i.e. `*g' ==
+        // \lambda p + (1-\lambda)\, q where 0 <= \lambda < 1 . A single
+        // random number is needed from `rnd' for each point.
+      : Random_generator_base<P>( (std::max)( (std::max)( (std::max)(to_double(s[0].x()), to_double(s[1].x())),
+                                                         (std::max)(to_double(s[0].y()), to_double(s[1].y()))),
+                                                         (std::max)(to_double(s[0].z()), to_double(s[1].z()))),
+                                  rnd) , _p(s[0]), _q(s[1])
+    {
+      generate_point();
+    }
+
     const P&  source() const { return _p; }
     const P&  target() const { return _q; }
     This& operator++()    {
@@ -373,13 +389,11 @@ struct Random_points_in_triangle_mesh_3
   typedef typename boost::property_traits<VertexPointMap>::value_type  P;
   typedef Generic_random_point_generator<
             typename boost::graph_traits <TriangleMesh>::face_descriptor ,
-            CGAL::Property_map_to_unary_function<typename CGAL::Triangle_from_face_descriptor_map<
+            CGAL::Property_map_to_unary_function<CGAL::Triangle_from_face_descriptor_map<
             TriangleMesh,VertexPointMap> >,
             Random_points_in_triangle_3<P, Creator> , P>                   Base;
   typedef typename CGAL::Triangle_from_face_descriptor_map<
-                     TriangleMesh,VertexPointMap>                          Pmap;
+                     TriangleMesh,VertexPointMap>                          Object_from_id;
-  typedef typename CGAL::Triangle_from_face_descriptor_map<
-                     TriangleMesh,VertexPointMap>                          Object_from_id_map;
   typedef typename boost::graph_traits<TriangleMesh>::face_descriptor      Id;
   typedef P result_type;
   typedef Random_points_in_triangle_mesh_3< TriangleMesh, VertexPointMap, Creator>  This;
@@ -387,14 +401,14 @@ struct Random_points_in_triangle_mesh_3
 
   Random_points_in_triangle_mesh_3( const TriangleMesh& mesh,Random& rnd = get_default_random())
     : Base( faces(mesh),
-            CGAL::Property_map_to_unary_function<Pmap>(Pmap(&mesh, get(vertex_point, mesh))),
+            CGAL::Property_map_to_unary_function<Object_from_id>(Object_from_id(&mesh, get(vertex_point, mesh))),
             internal::Apply_approx_sqrt<typename Kernel_traits<P>::Kernel::Compute_squared_area_3>(),
             rnd )
   {
   }
   Random_points_in_triangle_mesh_3( const TriangleMesh& mesh, VertexPointMap vpm, Random& rnd = get_default_random())
     : Base( faces(mesh),
-            CGAL::Property_map_to_unary_function<Pmap>(Pmap(&mesh, vpm)),
+            CGAL::Property_map_to_unary_function<Object_from_id>(Object_from_id(&mesh, vpm)),
             internal::Apply_approx_sqrt<typename Kernel_traits<P>::Kernel::Compute_squared_area_3>(),
             rnd )
   {
@@ -414,6 +428,62 @@ struct Random_points_in_triangle_mesh_3
   }
 };
 
+template <class EdgeListGraph,
+          class VertexPointMap = typename boost::property_map<EdgeListGraph,
+                                                              CGAL::vertex_point_t>::const_type,
+          class Creator = Creator_uniform_3<
+                            typename Kernel_traits< typename boost::property_traits<VertexPointMap>::value_type >::Kernel::RT,
+                            typename boost::property_traits<VertexPointMap>::value_type >
+>
+struct Random_points_on_edge_list_graph_3
+  : public Generic_random_point_generator<
+             typename boost::graph_traits <EdgeListGraph>::edge_descriptor,
+             CGAL::Property_map_to_unary_function<CGAL::Segment_from_edge_descriptor_map<
+                                                  EdgeListGraph, VertexPointMap > >,
+             Random_points_on_segment_3<typename boost::property_traits<VertexPointMap>::value_type, Creator>,
+             typename boost::property_traits<VertexPointMap>::value_type>
+{
+  typedef typename boost::property_traits<VertexPointMap>::value_type  P;
+  typedef Generic_random_point_generator<
+            typename boost::graph_traits <EdgeListGraph>::edge_descriptor,
+            CGAL::Property_map_to_unary_function<CGAL::Segment_from_edge_descriptor_map<
+                                                 EdgeListGraph, VertexPointMap > >,
+            Random_points_on_segment_3<P, Creator> , P>                    Base;
+  typedef typename CGAL::Segment_from_edge_descriptor_map<
+                     EdgeListGraph,VertexPointMap>                          Object_from_id;
+  typedef typename boost::graph_traits<EdgeListGraph>::edge_descriptor      Id;
+  typedef P result_type;
+  typedef Random_points_on_edge_list_graph_3< EdgeListGraph, VertexPointMap, Creator>  This;
+
+  Random_points_on_edge_list_graph_3( const EdgeListGraph& mesh,Random& rnd = get_default_random())
+    : Base( edges(mesh),
+            CGAL::Property_map_to_unary_function<Object_from_id>(Object_from_id(&mesh, get(vertex_point, mesh))),
+            internal::Apply_approx_sqrt<typename Kernel_traits<P>::Kernel::Compute_squared_length_3>(),
+            rnd )
+  {
+  }
+  Random_points_on_edge_list_graph_3( const EdgeListGraph& mesh, VertexPointMap vpm, Random& rnd = get_default_random())
+    : Base( edges(mesh),
+            CGAL::Property_map_to_unary_function<Object_from_id>(Object_from_id(&mesh, vpm)),
+            internal::Apply_approx_sqrt<typename Kernel_traits<P>::Kernel::Compute_squared_length_3>(),
+            rnd )
+  {
+  }
+  This& operator++() {
+    Base::generate_point();
+    return *this;
+  }
+  This operator++(int) {
+    This tmp = *this;
+    ++(*this);
+    return tmp;
+  }
+  double mesh_length() const
+  {
+    return this->sum_of_weights();
+  }
+};
+
 namespace internal
 {