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fix the implementation of is_outward_oriented(polygon mesh) 

this implementation does not require the construction of the normal,
and is based only on Kernel predicates
This commit is contained in:
Jane Tournois 2017-04-14 17:42:06 +02:00 committed by Sébastien Loriot
parent ce8a0be55e
commit 6c2ee8a35e
1 changed files with 57 additions and 15 deletions
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72
Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/orientation.h
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@ -26,7 +26,6 @@
#include <algorithm>
#include <CGAL/Polygon_mesh_processing/compute_normal.h>
#include <CGAL/Polygon_mesh_processing/internal/named_function_params.h>
#include <CGAL/Polygon_mesh_processing/internal/named_params_helper.h>
#include <CGAL/boost/graph/helpers.h>
@ -40,23 +39,28 @@ namespace CGAL {
namespace Polygon_mesh_processing {
namespace internal{
template <class Less_xyz, class VPmap>
struct Compare_vertex_points_xyz_3{
Less_xyz less;
template <class GT, class VPmap>
struct Compare_vertex_points_z_3
{
typename GT::Compare_z_3 compare_z;
VPmap vpmap;
Compare_vertex_points_xyz_3(VPmap const& vpmap)
: vpmap(vpmap){}
Compare_vertex_points_z_3(VPmap const& vpmap, const GT& gt)
: vpmap(vpmap)
{
compare_z = gt.compare_z_3_object();
}
typedef bool result_type;
template <class vertex_descriptor>
bool operator()(vertex_descriptor v1, vertex_descriptor v2) const
{
return less(get(vpmap, v1), get(vpmap, v2));
return CGAL::SMALLER == compare_z(get(vpmap, v1), get(vpmap, v2));
}
};
template<typename Kernel, typename PM, typename NamedParameters>
bool is_outward_oriented(typename boost::graph_traits<PM>::vertex_descriptor vd,
const PM& pmesh,
@ -117,17 +121,55 @@ bool is_outward_oriented(const PolygonMesh& pmesh,
VPMap vpmap = choose_param(get_param(np, vertex_point),
get_const_property_map(vertex_point, pmesh));
//Kernel
typedef typename GetGeomTraits<PolygonMesh, NamedParameters>::type Kernel;
internal::Compare_vertex_points_xyz_3<typename Kernel::Less_xyz_3, VPMap >
less_xyz(vpmap);
typedef typename GetGeomTraits<PolygonMesh, NamedParameters>::type GT;
GT gt = choose_param(get_param(np, geom_traits), GT());
//find the vertex with maximal z coordinate
typename boost::graph_traits<PolygonMesh>::vertex_iterator vbegin, vend;
cpp11::tie(vbegin, vend) = vertices(pmesh);
typename boost::graph_traits<PolygonMesh>::vertex_iterator v_min
= std::min_element(vbegin, vend, less_xyz);
return internal::is_outward_oriented<Kernel>(*v_min, pmesh, np);
internal::Compare_vertex_points_z_3<GT, VPMap> less_z(vpmap, gt);
typename boost::graph_traits<PolygonMesh>::vertex_iterator v_max_it
= std::max_element(vbegin, vend, less_z);
typename boost::graph_traits<PolygonMesh>::vertex_descriptor v_max = *v_max_it;
//among the incident edges to v_max,
// find one of the edges e with the minimal slope
typedef typename boost::graph_traits<PolygonMesh>::halfedge_descriptor halfedge_descriptor;
halfedge_descriptor min_slope_he = halfedge(v_max, pmesh);
CGAL_assertion(v_max == target(min_slope_he, pmesh));
typename GT::Compare_slope_3 compare_slope = gt.compare_slope_3_object();
BOOST_FOREACH(halfedge_descriptor he, halfedges_around_target(v_max, pmesh))
{
CGAL_assertion(v_max == target(min_slope_he, pmesh));
CGAL_assertion(v_max == target(he, pmesh));
if(CGAL::SMALLER == compare_slope(get(vpmap, v_max),
get(vpmap, source(min_slope_he, pmesh)),
get(vpmap, v_max),
get(vpmap, source(he, pmesh))))
{
min_slope_he = he;
}
}
//around that edge, there are two faces(because the mesh is without borders),
//take the face f for which the other edge incident to f and v has the minimal slope
//Note we only keep the corresponding halfedge
if(CGAL::SMALLER != compare_slope(get(vpmap, v_max),
get(vpmap, source(min_slope_he, pmesh)),
get(vpmap, v_max),
get(vpmap, source(prev(opposite(min_slope_he, pmesh), pmesh), pmesh))))
min_slope_he = opposite(min_slope_he, pmesh);
//check that the normal to f has z > 0
typename GT::Angle_3 angle_3 = gt.angle_3_object();
typename GT::Vector_3 vertical(0, 0, 1);
return CGAL::ACUTE == angle_3(get(vpmap, source(min_slope_he, pmesh)),
get(vpmap, target(min_slope_he, pmesh)),
get(vpmap, target(next(min_slope_he, pmesh), pmesh)),
vertical);
}
///\cond SKIP_IN_MANUAL