cgal/Surface_mesh_approximation/include/CGAL/Approximation_l2_traits.h

200 lines
7.2 KiB
C++

#ifndef CGAL_APPROXIMATION_L2_TRAITS_H
#define CGAL_APPROXIMATION_L2_TRAITS_H
#include <CGAL/license/Surface_mesh_approximation.h>
#include <CGAL/Kernel/global_functions.h>
#include <CGAL/squared_distance_3.h>
#include <CGAL/linear_least_squares_fitting_3.h>
#include <boost/graph/graph_traits.hpp>
#include <boost/unordered_map.hpp>
#include <list>
namespace CGAL {
/*!
* \ingroup PkgTSMA
* @brief Approximation traits for L2 metric.
*
* \cgalModels`Approximation_traits`
*
* @tparam TriangleMesh a triangle `FaceListGraph`
* @tparam VertexPointMap a property map with `boost::graph_traits<TriangleMesh>::%vertex_descriptor`
as key type, GeomTraits::Point_3 as value type
* @tparam GeomTraits geometric traits
*/
template <typename TriangleMesh,
typename VertexPointMap
= typename boost::property_map<TriangleMesh, boost::vertex_point_t>::type,
typename GeomTraits
= typename TriangleMesh::Traits>
class Approximation_l2_traits {
typedef typename GeomTraits::FT FT;
typedef typename GeomTraits::Point_3 Point_3;
typedef typename boost::graph_traits<TriangleMesh>::face_descriptor face_descriptor;
typedef typename boost::graph_traits<TriangleMesh>::halfedge_descriptor halfedge_descriptor;
typedef CGAL::internal::face_property_t<FT> Face_area_tag;
typedef typename CGAL::internal::dynamic_property_map<TriangleMesh, Face_area_tag >::type Face_area_map;
public:
// type required by the `Approximation_traits` concept
typedef typename GeomTraits::Plane_3 Proxy;
// constructor
Approximation_l2_traits(const TriangleMesh &tm, const VertexPointMap &vpmap)
: m_tm(&tm), m_vpmap(vpmap){
m_famap = CGAL::internal::add_property(
Face_area_tag("VSA-face_area"), const_cast<TriangleMesh &>(*m_tm));
BOOST_FOREACH(face_descriptor f, faces(*m_tm)) {
const halfedge_descriptor he = halfedge(f, *m_tm);
const Point_3 &p0 = m_vpmap[source(he, *m_tm)];
const Point_3 &p1 = m_vpmap[target(he, *m_tm)];
const Point_3 &p2 = m_vpmap[target(next(he, *m_tm), *m_tm)];
put(m_famap, f, std::sqrt(CGAL::to_double(CGAL::squared_area(p0, p1, p2))));
}
}
// member function required by the `Approximation_traits` concept
// It is a function that takes a facet and a proxy, returns the L21 error between them.
FT compute_error(const face_descriptor &f, const Proxy &px) const {
halfedge_descriptor he = halfedge(f, *m_tm);
const Point_3 &p0 = m_vpmap[source(he, *m_tm)];
const Point_3 &p1 = m_vpmap[target(he, *m_tm)];
const Point_3 &p2 = m_vpmap[target(next(he, *m_tm), *m_tm)];
const FT sq_d0 = CGAL::squared_distance(p0, px.fit_plane);
const FT sq_d1 = CGAL::squared_distance(p1, px.fit_plane);
const FT sq_d2 = CGAL::squared_distance(p2, px.fit_plane);
const FT d0(std::sqrt(CGAL::to_double(sq_d0)));
const FT d1(std::sqrt(CGAL::to_double(sq_d1)));
const FT d2(std::sqrt(CGAL::to_double(sq_d2)));
return (sq_d0 + sq_d1 + sq_d2 + d0 * d1 + d1 * d2 + d2 * d0) * get(m_famap, f) / FT(6.0);
}
// member function required by the `Approximation_traits` concept
// It returns the proxy fitted from the facets from beg to end.
template <typename FacetIterator>
Proxy fit_proxy(const FacetIterator beg, const FacetIterator end) const {
CGAL_assertion(beg != end);
std::list<Triangle_3> tris;
for (FacetIterator fitr = beg; fitr != end; ++fitr) {
halfedge_descriptor he = halfedge(*fitr, *m_tm);
const Point_3 &p0 = m_vpmap[source(he, *m_tm)];
const Point_3 &p1 = m_vpmap[target(he, *m_tm)];
const Point_3 &p2 = m_vpmap[target(next(he, *m_tm), *m_tm)];
tris.push_back(Triangle_3(p0, p1, p2));
}
// construct and fit proxy plane
Proxy px;
CGAL::linear_least_squares_fitting_3(
tris.begin(),
tris.end(),
px,
CGAL::Dimension_tag<2>());
// TODO: check and flip plane normal
return px;
}
private:
const TriangleMesh *m_tm;
const VertexPointMap m_vpmap;
Face_area_map m_famap;
};
// specializaiton for point map
template <typename TriangleMesh, typename GeomTraits>
class Approximation_l2_traits<TriangleMesh,
typename boost::property_map<TriangleMesh, boost::vertex_point_t>::type,
GeomTraits> {
typedef typename GeomTraits::FT FT;
typedef typename GeomTraits::Point_3 Point_3;
typedef typename boost::graph_traits<TriangleMesh>::face_descriptor face_descriptor;
typedef typename boost::graph_traits<TriangleMesh>::halfedge_descriptor halfedge_descriptor;
typedef CGAL::internal::face_property_t<FT> Face_area_tag;
typedef typename CGAL::internal::dynamic_property_map<TriangleMesh, Face_area_tag >::type Face_area_map;
public:
// type required by the `Approximation_traits` concept
typedef typename GeomTraits::Plane_3 Proxy;
// constructor
Approximation_l2_traits(const TriangleMesh &tm)
: m_tm(&tm), m_vpmap(get(boost::vertex_point, const_cast<TriangleMesh &>(tm))){
m_famap = CGAL::internal::add_property(
Face_area_tag("VSA-face_area"), const_cast<TriangleMesh &>(*m_tm));
BOOST_FOREACH(face_descriptor f, faces(*m_tm)) {
const halfedge_descriptor he = halfedge(f, *m_tm);
const Point_3 &p0 = m_vpmap[source(he, *m_tm)];
const Point_3 &p1 = m_vpmap[target(he, *m_tm)];
const Point_3 &p2 = m_vpmap[target(next(he, *m_tm), *m_tm)];
put(m_famap, f, std::sqrt(CGAL::to_double(CGAL::squared_area(p0, p1, p2))));
}
}
// member function required by the `Approximation_traits` concept
// It is a function that takes a facet and a proxy, returns the L21 error between them.
FT compute_error(const face_descriptor &f, const Proxy &px) const {
halfedge_descriptor he = halfedge(f, *m_tm);
const Point_3 &p0 = m_vpmap[source(he, *m_tm)];
const Point_3 &p1 = m_vpmap[target(he, *m_tm)];
const Point_3 &p2 = m_vpmap[target(next(he, *m_tm), *m_tm)];
const FT sq_d0 = CGAL::squared_distance(p0, px.fit_plane);
const FT sq_d1 = CGAL::squared_distance(p1, px.fit_plane);
const FT sq_d2 = CGAL::squared_distance(p2, px.fit_plane);
const FT d0(std::sqrt(CGAL::to_double(sq_d0)));
const FT d1(std::sqrt(CGAL::to_double(sq_d1)));
const FT d2(std::sqrt(CGAL::to_double(sq_d2)));
return (sq_d0 + sq_d1 + sq_d2 + d0 * d1 + d1 * d2 + d2 * d0) * get(m_famap, f) / FT(6.0);
}
// member function required by the `Approximation_traits` concept
// It returns the proxy fitted from the facets from beg to end.
template <typename FacetIterator>
Proxy fit_proxy(const FacetIterator beg, const FacetIterator end) const {
CGAL_assertion(beg != end);
std::list<Triangle_3> tris;
for (FacetIterator fitr = beg; fitr != end; ++fitr) {
halfedge_descriptor he = halfedge(*fitr, *m_tm);
const Point_3 &p0 = m_vpmap[source(he, *m_tm)];
const Point_3 &p1 = m_vpmap[target(he, *m_tm)];
const Point_3 &p2 = m_vpmap[target(next(he, *m_tm), *m_tm)];
tris.push_back(Triangle_3(p0, p1, p2));
}
// construct and fit proxy plane
Proxy px;
CGAL::linear_least_squares_fitting_3(
tris.begin(),
tris.end(),
px,
CGAL::Dimension_tag<2>());
// TODO: check and flip plane normal
return px;
}
private:
const TriangleMesh *m_tm;
const VertexPointMap m_vpmap;
Face_area_map m_famap;
};
} // namespace CGAL
#endif // CGAL_APPROXIMATION_L2_TRAITS_H