void geometryUtils::subdivide(Polyhedron& P) {
if (P.size_of_facets() == 0)
return;
// We use that new vertices/halfedges/facets are appended at the end.
std::size_t nv = P.size_of_vertices();
Vertex_iterator last_v = P.vertices_end();
--last_v; // the last of the old vertices
Edge_iterator last_e = P.edges_end();
--last_e; // the last of the old edges
Facet_iterator last_f = P.facets_end();
--last_f; // the last of the old facets
Facet_iterator f = P.facets_begin(); // create new center vertices
do {
geometryUtils::subdivide_create_center_vertex(P, f);
} while (f++ != last_f);
std::vector<Point_3> pts; // smooth the old vertices
pts.reserve(nv); // get intermediate space for the new points
++last_v; // make it the past-the-end position again
std::transform(P.vertices_begin(), last_v, std::back_inserter(pts),
Smooth_old_vertex());
std::copy(pts.begin(), pts.end(), P.points_begin());
Edge_iterator e = P.edges_begin(); // flip the old edges
++last_e; // make it the past-the-end position again
while (e != last_e) {
Halfedge_handle h = e;
++e; // careful, incr. before flip since flip destroys current edge
geometryUtils::subdivide_flip_edge(P, h);
};
CGAL_postcondition(P.is_valid());
};
// Subdivide each facet of the lcc by using sqrt(3)-subdivision.
void
subdivide_lcc_3 (LCC & m)
{
if (m.number_of_darts () == 0)
return;
LCC::size_type mark = m.get_new_mark ();
LCC::size_type treated = m.get_new_mark ();
m.negate_mark (mark); // All the old darts are marked in O(1).
// 1) We smoth the old vertices.
std::vector <std::pair<Point_3, Dart_handle> > vertices; // smooth the old vertices
vertices.reserve (m.number_of_attributes<0> ()); // get intermediate space
std::transform (m.vertex_attributes().begin (),
m.vertex_attributes().end (),
std::back_inserter (vertices),
Smooth_old_vertex (m, mark));
// 2) We subdivide each facet.
m.negate_mark (treated); // All the darts are marked in O(1).
unsigned int nb = 0;
for (LCC::Dart_range::iterator it (m.darts().begin ());
m.number_of_marked_darts (treated) > 0; ++it)
{
++nb;
if (m.is_marked (it, treated))
{
// We unmark the darts of the facet to process only once dart/facet.
CGAL::unmark_cell < LCC, 2 > (m, it, treated);
// We triangulate the facet.
m.insert_barycenter_in_cell<2>(it);
}
}
CGAL_assertion (m.is_whole_map_unmarked (treated));
CGAL_assertion (m.is_valid ());
m.free_mark (treated);
// 3) We update the coordinates of old vertices.
for (std::vector<std::pair<Point_3, Dart_handle> >::iterator
vit=vertices.begin(); vit!=vertices.end(); ++vit)
{
m.point(vit->second)=vit->first;
}
// 4) We flip all the old edges.
m.negate_mark (mark); // Now only new darts are marked.
Dart_handle d2 =LCC::null_handle;
for (LCC::Dart_range::iterator it (m.darts().begin ());
it != m.darts().end ();)
{
d2 = it++;
if (!m.is_marked (d2, mark)) // This is an old dart.
{
// We process only the last dart of a same edge.
if (!m.is_free(d2,2) && (m.beta(d2,2,3)==m.beta(d2,3,2)))
{
if (m.is_marked(m.beta(d2,2), mark) &&
(m.is_free(d2,3) ||
(m.is_marked(m.beta(d2,3), mark) &&
m.is_marked(m.beta(d2,2,3), mark))))
{
flip_edge (m, d2);
m.mark(d2, mark);
}
else
m.mark (d2, mark);
}
else
m.mark (d2, mark);
}
}
CGAL_assertion (m.is_whole_map_marked (mark));
m.free_mark (mark);
CGAL_postcondition ( m.is_valid ());
}
