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add a named parameter to avoid flipping high triangles

This commit is contained in:
Sébastien Loriot 2022-06-07 16:15:53 +02:00
parent 6f526172dd
commit 6869bddeaa
4 changed files with 28 additions and 11 deletions
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5
Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/internal/Isotropic_remeshing/remesh_impl.h
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@ -853,11 +853,12 @@ namespace internal {
mesh_, vpmap_, vcmap_, ecmap_, gt_,
cap_threshold, // bound on the angle: above 160 deg => cap
4, // bound on shortest/longest edge above 4 => needle
0);// collapse length threshold : not needed here
0,// collapse length threshold : not needed here
0); // flip triangle height threshold
std::array<halfedge_descriptor, 2> r2 = internal::is_badly_shaped(
face(opposite(he, mesh_), mesh_),
mesh_, vpmap_, vcmap_, ecmap_, gt_, cap_threshold, 4, 0);
mesh_, vpmap_, vcmap_, ecmap_, gt_, cap_threshold, 4, 0, 0);
const bool badly_shaped = (r1[0] != boost::graph_traits<PolygonMesh>::null_halfedge()//needle
|| r1[1] != boost::graph_traits<PolygonMesh>::null_halfedge()//cap

31
Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/repair_degeneracies.h
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@ -61,7 +61,8 @@ is_badly_shaped(const typename boost::graph_traits<TriangleMesh>::face_descripto
const Traits& gt,
const double cap_threshold, // angle over 160° ==> cap
const double needle_threshold, // longest edge / shortest edge over this ratio ==> needle
const double collapse_length_threshold) // max length of edges allowed to be collapsed
const double collapse_length_threshold, // max length of edges allowed to be collapsed
const double flip_triangle_height_threshold_squared) // max height of triangles allowed to be flipped
{
namespace PMP = CGAL::Polygon_mesh_processing;
@ -83,8 +84,14 @@ is_badly_shaped(const typename boost::graph_traits<TriangleMesh>::face_descripto
}
res = PMP::is_cap_triangle_face(f, tmesh, cap_threshold, parameters::vertex_point_map(vpm).geom_traits(gt));
if(res != null_h && !get(ecm, edge(res, tmesh)))
if( res != null_h && !get(ecm, edge(res, tmesh) ) &&
(flip_triangle_height_threshold_squared == 0 ||
typename Traits::Compare_squared_distance_3()( get(vpm, target(next(res,tmesh), tmesh)),
typename Traits::Line_3(get(vpm, source(res,tmesh)), get(vpm, target(res,tmesh))),
flip_triangle_height_threshold_squared) != LARGER ))
{
return make_array(null_h, res);
}
return make_array(null_h, null_h);
}
@ -100,13 +107,15 @@ void collect_badly_shaped_triangles(const typename boost::graph_traits<TriangleM
const double cap_threshold, // angle over this threshold (as a cosine) ==> cap
const double needle_threshold, // longest edge / shortest edge over this ratio ==> needle
const double collapse_length_threshold, // max length of edges allowed to be collapsed
const double flip_triangle_height_threshold_squared, // max height squared of triangles that can be flipped
HalfedgeContainer& edges_to_collapse,
HalfedgeContainer& edges_to_flip)
{
typedef typename boost::graph_traits<TriangleMesh>::halfedge_descriptor halfedge_descriptor;
std::array<halfedge_descriptor, 2> res = is_badly_shaped(f, tmesh, vpm, vcm, ecm, gt, cap_threshold,
needle_threshold, collapse_length_threshold);
needle_threshold,
collapse_length_threshold, flip_triangle_height_threshold_squared);
if(res[0] != boost::graph_traits<TriangleMesh>::null_halfedge())
{
@ -580,6 +589,9 @@ bool remove_almost_degenerate_faces(const FaceRange& face_range,
typedef typename boost::property_map<TriangleMesh, Vertex_property_tag>::type DVCM;
DVCM vcm = get(Vertex_property_tag(), tmesh);
const double flip_triangle_height_threshold_squared =
CGAL::square(choose_parameter(get_parameter(np, internal_np::flip_triangle_height_threshold), 0));
CGAL_precondition(is_valid_polygon_mesh(tmesh));
CGAL_precondition(is_triangle_mesh(tmesh));
@ -611,7 +623,8 @@ bool remove_almost_degenerate_faces(const FaceRange& face_range,
for(face_descriptor f : face_range)
{
internal::collect_badly_shaped_triangles(f, tmesh, vpm, vcm, ecm, gt,
cap_threshold, needle_threshold, collapse_length_threshold,
cap_threshold, needle_threshold,
collapse_length_threshold, flip_triangle_height_threshold_squared,
edges_to_collapse, edges_to_flip);
}
@ -671,7 +684,7 @@ bool remove_almost_degenerate_faces(const FaceRange& face_range,
// Verify that the element is still badly shaped
const std::array<halfedge_descriptor, 2> nc =
internal::is_badly_shaped(face(h, tmesh), tmesh, vpm, vcm, ecm, gt,
cap_threshold, needle_threshold, collapse_length_threshold);
cap_threshold, needle_threshold, collapse_length_threshold, flip_triangle_height_threshold_squared);
if(nc[0] != h)
{
@ -757,7 +770,8 @@ bool remove_almost_degenerate_faces(const FaceRange& face_range,
if(!is_border(hv, tmesh))
{
internal::collect_badly_shaped_triangles(face(hv, tmesh), tmesh, vpm, vcm, ecm, gt,
cap_threshold, needle_threshold, collapse_length_threshold,
cap_threshold, needle_threshold,
collapse_length_threshold, flip_triangle_height_threshold_squared,
edges_to_collapse, edges_to_flip);
}
}
@ -806,7 +820,7 @@ bool remove_almost_degenerate_faces(const FaceRange& face_range,
std::array<halfedge_descriptor,2> nc = internal::is_badly_shaped(face(h, tmesh), tmesh, vpm, vcm, ecm, gt,
cap_threshold, needle_threshold,
collapse_length_threshold);
collapse_length_threshold, flip_triangle_height_threshold_squared);
// Check the triangle is still a cap
if(nc[1] != h)
{
@ -868,7 +882,8 @@ bool remove_almost_degenerate_faces(const FaceRange& face_range,
CGAL_assertion(!is_border(h, tmesh));
std::array<halfedge_descriptor, 2> nc =
internal::is_badly_shaped(face(h, tmesh), tmesh, vpm, vcm, ecm, gt,
cap_threshold, needle_threshold, collapse_length_threshold);
cap_threshold, needle_threshold,
collapse_length_threshold, flip_triangle_height_threshold_squared);
if(nc[1] != boost::graph_traits<TriangleMesh>::null_halfedge() && nc[1] != h)
next_edges_to_flip.insert(nc[1]);

2
Polygon_mesh_processing/include/CGAL/Polygon_mesh_processing/shape_predicates.h
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@ -503,7 +503,7 @@ struct Is_cap_angle_over_threshold<K, true>
/// \ingroup PMP_predicates_grp
///
/// checks whether a triangle face is a cap.
/// A triangle is said to be a <i>cap</i> if one of the its angles is close to `180` degrees.
/// A triangle is said to be a <i>cap</i> if one of its angles is close to `180` degrees.
///
/// @tparam TriangleMesh a model of `FaceGraph`
/// @tparam NamedParameters a sequence of \ref bgl_namedparameters "Named Parameters"

1
STL_Extension/include/CGAL/STL_Extension/internal/parameters_interface.h
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@ -130,6 +130,7 @@ CGAL_add_named_parameter(match_faces_t, match_faces, match_faces)
CGAL_add_named_parameter(face_epsilon_map_t, face_epsilon_map, face_epsilon_map)
CGAL_add_named_parameter(maximum_number_t, maximum_number, maximum_number)
CGAL_add_named_parameter(use_one_sided_hausdorff_t, use_one_sided_hausdorff, use_one_sided_hausdorff)
CGAL_add_named_parameter(flip_triangle_height_threshold_t, flip_triangle_height_threshold, flip_triangle_height_threshold)
// List of named parameters that we use in the package 'Surface Mesh Simplification'
CGAL_add_named_parameter(get_cost_policy_t, get_cost_policy, get_cost)