void Scene_polyhedron_transform_item::direct_draw_edges() const {
  typedef Kernel::Point_3		Point;
  typedef Polyhedron::Edge_const_iterator	Edge_iterator;

  ::glDisable(GL_LIGHTING);
  ::glBegin(GL_LINES);
  Edge_iterator he;
  for(he = poly->edges_begin();
      he != poly->edges_end();
      he++)
  {
    const Point& a = he->vertex()->point();
    const Point& b = he->opposite()->vertex()->point();
    ::glVertex3d(a.x()-center_.x,a.y()-center_.y,a.z()-center_.z);
    ::glVertex3d(b.x()-center_.x,b.y()-center_.y,b.z()-center_.z);
  }
  ::glEnd();
  ::glEnable(GL_LIGHTING);
}
void subdiv_border( Polyhedron& P) {
    if ( P.size_of_facets() == 0)
        return;
    // We use that new halfedges are appended at the end.
    Edge_iterator last_e = P.edges_end();
    -- last_e;  // the last of the old edges
    Edge_iterator e = P.edges_begin(); // create trisected border edges
    do {
        if ( e->opposite()->is_border())
            trisect_border_halfedge( P, e->opposite());
        else if ( e->is_border())
            trisect_border_halfedge( P, e);
    } while ( e++ != last_e);
    e = P.edges_begin();               // smooth points on border edges
    std::vector<Point> pts;  // store new smoothed points temporarily
    do {
        if ( e->opposite()->is_border())
            smooth_border_vertices( e->opposite(), std::back_inserter(pts));
        else if ( e->is_border())
            smooth_border_vertices( e, std::back_inserter(pts));
    } while ( e++ != last_e);
    e = P.edges_begin(); // copy smoothed points back
    std::vector<Point>::iterator i = pts.begin();
    do {
        if ( e->opposite()->is_border()) {
            e->vertex()->point() = *i++;
            e->opposite()->vertex()->point() = *i++;
            e->opposite()->next()->vertex()->point() = *i++;
        } else if ( e->is_border()) {
            e->opposite()->vertex()->point() = *i++;
            e->vertex()->point() = *i++;
            e->next()->vertex()->point() = *i++;
        }
    } while ( e++ != last_e);
    CGAL_assertion( i == pts.end());
    CGAL_postcondition( P.is_valid());
}
void Scene_polyhedron_transform_item::compute_elements() const
{
     positions_lines.resize(0);
    typedef Kernel::Point_3		Point;
    typedef Polyhedron::Edge_const_iterator	Edge_iterator;

    Edge_iterator he;
    for(he = poly->edges_begin();
        he != poly->edges_end();
        he++)
    {
        const Point& a = he->vertex()->point();
        const Point& b = he->opposite()->vertex()->point();
        positions_lines.push_back(a.x()-center_.x);
        positions_lines.push_back(a.y()-center_.y);
        positions_lines.push_back(a.z()-center_.z);

        positions_lines.push_back(b.x()-center_.x);
        positions_lines.push_back(b.y()-center_.y);
        positions_lines.push_back(b.z()-center_.z);

    }
}
void
Scene_textured_polyhedron_item::compute_normals_and_vertices(void)
{
    positions_facets.resize(0);
    positions_lines.resize(0);
    textures_map_facets.resize(0);
    textures_map_lines.resize(0);
    normals.resize(0);

    typedef ::EPIC_kernel Kernel;
    typedef CGAL::Textured_items Items;
    typedef Kernel::Point_3 Point;
    typedef Kernel::Vector_3 Vector;
    typedef CGAL::Polyhedron_3<Kernel,Items> Base;

    typedef Base::Halfedge_around_facet_circulator Halfedge_around_facet_circulator;
    typedef Base::Edge_iterator Edge_iterator;
    typedef Base::Facet Facet;
    typedef Base::Facet_iterator Facet_iterator;

    //Facets
    Facet_iterator f = poly->facets_begin();

    for(f = poly->facets_begin();
        f != poly->facets_end();
        f++)
    {

        Halfedge_around_facet_circulator he = f->facet_begin();
        Halfedge_around_facet_circulator end = he;
        CGAL_For_all(he,end)
        {

            // If Flat shading:1 normal per polygon added once per vertex
            if (cur_shading == Flat || cur_shading == FlatPlusEdges)
            {

                Vector n = CGAL::Polygon_mesh_processing::
                  compute_face_normal(f, static_cast<Base&>(*poly));
                normals.push_back(n[0]);
                normals.push_back(n[1]);
                normals.push_back(n[2]);
            }

            // If Gouraud shading: 1 normal per vertex
            else if(cur_shading == Gouraud)
            {

                const Facet::Normal_3& n = he->vertex()->normal();
                normals.push_back(n[0]);
                normals.push_back(n[1]);
                normals.push_back(n[2]);
            }

            //position
            const Point& p = he->vertex()->point();
            positions_facets.push_back(p.x());
            positions_facets.push_back(p.y());
            positions_facets.push_back(p.z());
            positions_facets.push_back(1.0);

            const double u = he->vertex()->u();
            const double v = he->vertex()->v();
            textures_map_facets.push_back(u);
            textures_map_facets.push_back(v);
        }


    }
    //Lines
    typedef Kernel::Point_3		Point;
    typedef Base::Edge_iterator	Edge_iterator;

    Edge_iterator he;

    for(he = poly->edges_begin();
        he != poly->edges_end();
        he++)
    {

        const Point& a = he->vertex()->point();
        const Point& b = he->opposite()->vertex()->point();
        positions_lines.push_back(a.x());
        positions_lines.push_back(a.y());
        positions_lines.push_back(a.z());
        positions_lines.push_back(1.0);

        const double u = he->vertex()->u();
        const double v = he->vertex()->v();
        textures_map_lines.push_back(u);
        textures_map_lines.push_back(v);

        positions_lines.push_back(b.x());
        positions_lines.push_back(b.y());
        positions_lines.push_back(b.z());
        positions_lines.push_back(1.0);

        const double ou = he->opposite()->vertex()->u();
        const double ov = he->opposite()->vertex()->v();
        textures_map_lines.push_back(ou);
        textures_map_lines.push_back(ov);

    }

}