CGAL 6.1 - Polygon Mesh Processing

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Polygon_mesh_processing/isotropic_remeshing_with_custom_sizing_example.cpp
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Surface_mesh.h>
#include <CGAL/Polygon_mesh_processing/remesh.h>
#include <CGAL/Polygon_mesh_processing/IO/polygon_mesh_io.h>
#include <CGAL/Polygon_mesh_processing/bbox.h>
#include <fstream>
typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
typedef CGAL::Surface_mesh<K::Point_3> Mesh;
namespace PMP = CGAL::Polygon_mesh_processing;
// a sizing field that is increasing the size of edge along the y-axis
// starting at a minimum size at y-max and ending at a maximum size at
// y-min, with a linear interpolation of sizes in between the two extreme
// sizing values
struct My_sizing_field
{
double min_size, max_size;
double ymin, ymax;
My_sizing_field(double min_size, double max_size, double ymin, double ymax)
: min_size(min_size)
, max_size(max_size)
, ymin(ymin)
, ymax(ymax)
{}
double at(K::Point_3 p) const
{
double y=p.y();
return CGAL::square( (y-ymin)/(ymax-ymin) * (min_size - max_size) + max_size );
}
double at(const Mesh::Vertex_index v, const Mesh& mesh) const { return at(mesh.point(v)); }
std::optional<double> is_too_long(const Mesh::Vertex_index va,
const Mesh::Vertex_index vb,
const Mesh& mesh) const
{
// TODO: no mesh as parameters?
K::Point_3 mp = CGAL::midpoint(mesh.point(va), mesh.point(vb));
double sql_at = at(mp);
double sql = CGAL::squared_distance(mesh.point(va), mesh.point(vb));
if (sql > sql_at)
return sql / sql_at;
return std::nullopt;
}
std::optional<double> is_too_short(const Mesh::Halfedge_index h,
const Mesh& mesh) const
{
K::Point_3 mp = CGAL::midpoint(mesh.point(source(h, mesh)), mesh.point(target(h, mesh)));
double sql_at = at(mp);
double sql = CGAL::squared_distance(mesh.point(source(h, mesh)), mesh.point(target(h, mesh)));
if (sql < sql_at)
return sql / sql_at;
return std::nullopt;
}
K::Point_3 split_placement(const Mesh::Halfedge_index h,
const Mesh& mesh) const
{
return CGAL::midpoint(mesh.point(source(h, mesh)), mesh.point(target(h, mesh)));
}
void register_split_vertex(const Mesh::Vertex_index, const Mesh&) {}
};
int main(int argc, char* argv[])
{
const std::string filename = (argc > 1) ? argv[1] : CGAL::data_file_path("meshes/elk.off");
Mesh mesh;
if (!PMP::IO::read_polygon_mesh(filename, mesh) || !CGAL::is_triangle_mesh(mesh)) {
std::cerr << "Not a valid input file." << std::endl;
return 1;
}
std::cout << "Start remeshing of " << filename
<< " (" << num_faces(mesh) << " faces)..." << std::endl;
CGAL::Bbox_3 bb = PMP::bbox(mesh);
My_sizing_field sizing_field(0.1, 30, bb.ymin(), bb.ymax());
unsigned int nb_iter = 5;
PMP::isotropic_remeshing(
faces(mesh),
sizing_field,
mesh,
CGAL::parameters::number_of_iterations(nb_iter)
.number_of_relaxation_steps(3)
);
CGAL::IO::write_polygon_mesh("custom_remesh_out.off", mesh, CGAL::parameters::stream_precision(17));
std::cout << "Remeshing done." << std::endl;
return 0;
}
CGAL::Bbox_3
CGAL::Bbox_3::ymin
double ymin() const
CGAL::Bbox_3::ymax
double ymax() const
CGAL::Exact_predicates_inexact_constructions_kernel
CGAL::Surface_mesh
CGAL::square
NT square(const NT &x)
CGAL::is_triangle_mesh
bool is_triangle_mesh(const FaceGraph &g)
CGAL::IO::write_polygon_mesh
bool write_polygon_mesh(const std::string &fname, Graph &g, const NamedParameters &np=parameters::default_values())
CGAL::midpoint
CGAL::Point_2< Kernel > midpoint(const CGAL::Point_2< Kernel > &p, const CGAL::Point_2< Kernel > &q)
CGAL::squared_distance
Kernel::FT squared_distance(Type1< Kernel > obj1, Type2< Kernel > obj2)