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Robustification of most visible vertex normal computation

This commit is contained in:
Mael Rouxel-Labbé 2019-08-26 13:05:27 +02:00
parent 6da2cebc8d
commit ae60ff2d15
1 changed files with 27 additions and 27 deletions
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54
Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/compute_normal.h
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@ -297,17 +297,21 @@ typename GT::Vector_3 compute_normals_bisector(const typename GT::Vector_3& ni,
return traits.construct_sum_of_vectors_3_object()(ni, nj); // not normalized return traits.construct_sum_of_vectors_3_object()(ni, nj); // not normalized
} }
// @FIXME Handle the case of ni, nj and nk giving 3 points on a great circle
template <typename GT> template <typename GT>
typename GT::Vector_3 compute_normals_bisector(const typename GT::Vector_3& ni, typename GT::Vector_3 compute_normals_bisector(const typename GT::Vector_3& ni,
const typename GT::Vector_3& nj, const typename GT::Vector_3& nj,
const typename GT::Vector_3& nk, const typename GT::Vector_3& nk,
const GT& traits) const GT& traits)
{ {
typedef typename GT::FT FT;
typedef typename GT::Point_3 Point_3; typedef typename GT::Point_3 Point_3;
typedef typename GT::Vector_3 Vector_3; typedef typename GT::Vector_3 Vector_3;
Vector_3 nb = traits.construct_vector_3_object()(CGAL::NULL_VECTOR); typename GT::Construct_scaled_vector_3 cslv_3 = traits.construct_scaled_vector_3_object();
typename GT::Construct_sum_of_vectors_3 csv_3 = traits.construct_sum_of_vectors_3_object();
typename GT::Construct_vector_3 cv_3 = traits.construct_vector_3_object();
Vector_3 nb = cv_3(CGAL::NULL_VECTOR);
if(almost_equal(ni, nj, traits)) if(almost_equal(ni, nj, traits))
{ {
@ -329,27 +333,28 @@ typename GT::Vector_3 compute_normals_bisector(const typename GT::Vector_3& ni,
CGAL_assertion(ni != nj); CGAL_assertion(ni != nj);
CGAL_assertion(ni != nk); CGAL_assertion(ni != nk);
CGAL_assertion(nj != nk); CGAL_assertion(nj != nk);
CGAL_assertion(!traits.collinear_3_object()(CGAL::ORIGIN + ni, CGAL_assertion(!traits.collinear_3_object()(CGAL::ORIGIN + ni, CGAL::ORIGIN + nj, CGAL::ORIGIN + nk));
CGAL::ORIGIN + nj,
CGAL::ORIGIN + nk));
#ifdef CGAL_PMP_COMPUTE_NORMAL_DEBUG_PP #ifdef CGAL_PMP_COMPUTE_NORMAL_DEBUG_PP
std::cout << "Triplet: ni[" << ni << "] nj[" << nj << "] nk[" << nk << "]" << std::endl; std::cout << "Triplet: ni[" << ni << "] nj[" << nj << "] nk[" << nk << "]" << std::endl;
#endif #endif
const Point_3 c = traits.construct_circumcenter_3_object()(CGAL::ORIGIN + ni, const Point_3 c = traits.construct_circumcenter_3_object()(CGAL::ORIGIN + ni, CGAL::ORIGIN + nj, CGAL::ORIGIN + nk);
CGAL::ORIGIN + nj, if(c == CGAL::ORIGIN)
CGAL::ORIGIN + nk); {
CGAL_assertion(c != CGAL::ORIGIN); // will happen if the three vectors live in the same plan, return some weighted sum
const FT third = FT(1)/FT(3);
return csv_3(csv_3(cslv_3(ni, third), cslv_3(nj, third)), cslv_3(nk, third));
}
nb = traits.construct_vector_3_object()(CGAL::ORIGIN, c); // note that this isn't normalized nb = cv_3(CGAL::ORIGIN, c); // note that this isn't normalized
} }
return nb; return nb;
} }
template <typename PolygonMesh, typename FaceNormalVector, typename GT> template <typename PolygonMesh, typename FaceNormalVector, typename GT>
std::pair<typename GT::Vector_3, bool> typename GT::Vector_3
compute_most_visible_normal_2_points(std::vector<typename boost::graph_traits<PolygonMesh>::face_descriptor>& incident_faces, compute_most_visible_normal_2_points(std::vector<typename boost::graph_traits<PolygonMesh>::face_descriptor>& incident_faces,
const FaceNormalVector& face_normals, const FaceNormalVector& face_normals,
const GT& traits) const GT& traits)
@ -358,14 +363,15 @@ compute_most_visible_normal_2_points(std::vector<typename boost::graph_traits<Po
typedef typename GT::Vector_3 Vector_3; typedef typename GT::Vector_3 Vector_3;
typedef typename boost::property_traits<FaceNormalVector>::reference Vector_ref; typedef typename boost::property_traits<FaceNormalVector>::reference Vector_ref;
typename GT::Compute_scalar_product_3 sp = traits.compute_scalar_product_3_object(); typename GT::Compute_scalar_product_3 sp_3 = traits.compute_scalar_product_3_object();
typename GT::Construct_vector_3 cv_3 = traits.construct_vector_3_object();
#ifdef CGAL_PMP_COMPUTE_NORMAL_DEBUG_PP #ifdef CGAL_PMP_COMPUTE_NORMAL_DEBUG_PP
std::cout << "Trying to find enclosing normal with 2 normals" << std::endl; std::cout << "Trying to find enclosing normal with 2 normals" << std::endl;
#endif #endif
FT min_sp = -1; FT min_sp = -1;
Vector_3 n = traits.construct_vector_3_object()(CGAL::NULL_VECTOR); Vector_3 n = cv_3(CGAL::NULL_VECTOR);
const std::size_t nif = incident_faces.size(); const std::size_t nif = incident_faces.size();
for(int i=0; i<nif; ++i) for(int i=0; i<nif; ++i)
@ -377,12 +383,11 @@ compute_most_visible_normal_2_points(std::vector<typename boost::graph_traits<Po
const Vector_3 nb = compute_normals_bisector(ni, nj, traits); const Vector_3 nb = compute_normals_bisector(ni, nj, traits);
// Degeneracies like ni == -nj or a numerical error in the construction of 'nb' // Degeneracies like ni == -nj or a numerical error in the construction of 'nb' can happen.
// can happen. In that case, we can't compute a most visible normal
if(traits.equal_3_object()(nb, CGAL::NULL_VECTOR)) if(traits.equal_3_object()(nb, CGAL::NULL_VECTOR))
return std::make_pair(CGAL::NULL_VECTOR, false); return CGAL::NULL_VECTOR;
const FT sp_bi = sp(nb, ni); const FT sp_bi = sp_3(nb, ni);
CGAL_assertion(sp_bi >= 0); CGAL_assertion(sp_bi >= 0);
if(sp_bi <= min_sp) if(sp_bi <= min_sp)
@ -396,8 +401,7 @@ compute_most_visible_normal_2_points(std::vector<typename boost::graph_traits<Po
} }
} }
// note that 'n' can be NULL_VECTOR here if the min circle is a diametric cycle return n;
return std::make_pair(n, true);
} }
template <typename PolygonMesh, typename FaceNormalVector, typename GT> template <typename PolygonMesh, typename FaceNormalVector, typename GT>
@ -410,9 +414,6 @@ compute_most_visible_normal_3_points(const std::vector<typename boost::graph_tra
typedef typename GT::Vector_3 Vector_3; typedef typename GT::Vector_3 Vector_3;
typedef typename boost::property_traits<FaceNormalVector>::reference Vector_ref; typedef typename boost::property_traits<FaceNormalVector>::reference Vector_ref;
typename GT::Compute_scalar_product_3 sp = traits.compute_scalar_product_3_object();
typename GT::Construct_sum_of_vectors_3 csv = traits.construct_sum_of_vectors_3_object();
#ifdef CGAL_PMP_COMPUTE_NORMAL_DEBUG_PP #ifdef CGAL_PMP_COMPUTE_NORMAL_DEBUG_PP
std::cout << "Trying to find enclosing normal with 3 normals" << std::endl; std::cout << "Trying to find enclosing normal with 3 normals" << std::endl;
#endif #endif
@ -437,7 +438,7 @@ compute_most_visible_normal_3_points(const std::vector<typename boost::graph_tra
if(traits.equal_3_object()(nb, CGAL::NULL_VECTOR)) if(traits.equal_3_object()(nb, CGAL::NULL_VECTOR))
return nb; return nb;
FT sp_bi = sp(nb, ni); FT sp_bi = traits.compute_scalar_product_3_object()(nb, ni);
if(sp_bi < FT(0)) if(sp_bi < FT(0))
{ {
nb = traits.construct_opposite_vector_3_object()(nb); nb = traits.construct_opposite_vector_3_object()(nb);
@ -488,11 +489,10 @@ compute_vertex_normal_most_visible_min_circle(typename boost::graph_traits<Polyg
if(incident_faces.size() == 1) if(incident_faces.size() == 1)
return get(face_normals, incident_faces.front()); return get(face_normals, incident_faces.front());
std::pair<Vector_3, bool> res = compute_most_visible_normal_2_points<PolygonMesh>(incident_faces, face_normals, traits); Vector_3 res = compute_most_visible_normal_2_points<PolygonMesh>(incident_faces, face_normals, traits);
if(!res.second || // won't be able to find a most visible normal if(res != CGAL::NULL_VECTOR) // found a valid normal through 2 point min circle
(res.second && res.first != CGAL::NULL_VECTOR)) // found a valid normal through 2 point min circle return res;
return res.first;
CGAL_assertion(incident_faces.size() > 2); CGAL_assertion(incident_faces.size() > 2);