CGAL 4.7 - Planar Parameterization of Triangulated Surface Meshes: Surface_mesh_parameterization/Complete_parameterization_example.cpp

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CGAL 4.7 - Planar Parameterization of Triangulated Surface Meshes

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Surface_mesh_parameterization/Complete_parameterization_example.cpp
#include <CGAL/Simple_cartesian.h>
#include <CGAL/Polyhedron_3.h>
#include <CGAL/IO/Polyhedron_iostream.h>
#include <CGAL/Parameterization_polyhedron_adaptor_3.h>
#include <CGAL/parameterize.h>
#include <CGAL/Discrete_authalic_parameterizer_3.h>
#include <CGAL/Square_border_parameterizer_3.h>
#include <CGAL/Parameterization_mesh_patch_3.h>
#include <CGAL/Eigen_solver_traits.h>
#include <iostream>
#include <fstream>
#include <cstdlib>
// ----------------------------------------------------------------------------
// Private types
// ----------------------------------------------------------------------------
typedef CGAL::Simple_cartesian<double> Kernel;
typedef CGAL::Polyhedron_3<Kernel> Polyhedron;
// Polyhedron adaptor
typedef CGAL::Parameterization_polyhedron_adaptor_3<Polyhedron>
Parameterization_polyhedron_adaptor;
// Type describing a border or seam as a vertex list
typedef std::list<Parameterization_polyhedron_adaptor::Vertex_handle>
Seam;
// ----------------------------------------------------------------------------
// Private functions
// ----------------------------------------------------------------------------
// If the mesh is a topological disk, extract its longest border,
// else compute a very simple cut to make it homeomorphic to a disk.
// Return the border of this region (empty on error)
//
// CAUTION: this cutting algorithm is very naive. Write your own!
static Seam cut_mesh(Parameterization_polyhedron_adaptor& mesh_adaptor)
{
// Helper class to compute genus or extract borders
typedef CGAL::Parameterization_mesh_feature_extractor<Parameterization_polyhedron_adaptor>
Mesh_feature_extractor;
Seam seam; // returned list
// Get reference to Polyhedron_3 mesh
Polyhedron& mesh = mesh_adaptor.get_adapted_mesh();
// Extract mesh borders and compute genus
Mesh_feature_extractor feature_extractor(mesh_adaptor);
int nb_borders = feature_extractor.get_nb_borders();
int genus = feature_extractor.get_genus();
// If mesh is a topological disk
if (genus == 0 && nb_borders > 0)
{
// Pick the longest border
seam = feature_extractor.get_longest_border();
}
else // if mesh is *not* a topological disk, create a virtual cut
{
const int CUT_LENGTH = 6;
// Build consecutive halfedges array
Polyhedron::Halfedge_handle seam_halfedges[CUT_LENGTH];
seam_halfedges[0] = mesh.halfedges_begin();
if (seam_halfedges[0] == NULL)
return seam; // return empty list
int i;
for (i=1; i<CUT_LENGTH; i++)
{
seam_halfedges[i] = seam_halfedges[i-1]->next()->opposite()->next();
if (seam_halfedges[i] == NULL)
return seam; // return empty list
}
// Convert halfedges array to two-ways vertices list
for (i=0; i<CUT_LENGTH; i++)
seam.push_back(seam_halfedges[i]->vertex());
for (i=CUT_LENGTH-1; i>=0; i--)
seam.push_back(seam_halfedges[i]->opposite()->vertex());
}
return seam;
}
// Dump parameterized mesh to an eps file
static bool write_file_eps(const Parameterization_polyhedron_adaptor& mesh_adaptor,
const char *pFilename,
double scale = 500.0)
{
const Polyhedron& mesh = mesh_adaptor.get_adapted_mesh();
std::ofstream out(pFilename);
if(!out)
return false;
CGAL::set_ascii_mode(out);
// compute bounding box
double xmin,xmax,ymin,ymax;
xmin = ymin = xmax = ymax = 0;
Polyhedron::Halfedge_const_iterator pHalfedge;
for (pHalfedge = mesh.halfedges_begin();
pHalfedge != mesh.halfedges_end();
pHalfedge++)
{
double x1 = scale * mesh_adaptor.info(pHalfedge->prev())->uv().x();
double y1 = scale * mesh_adaptor.info(pHalfedge->prev())->uv().y();
double x2 = scale * mesh_adaptor.info(pHalfedge)->uv().x();
double y2 = scale * mesh_adaptor.info(pHalfedge)->uv().y();
xmin = (std::min)(xmin,x1);
xmin = (std::min)(xmin,x2);
xmax = (std::max)(xmax,x1);
xmax = (std::max)(xmax,x2);
ymax = (std::max)(ymax,y1);
ymax = (std::max)(ymax,y2);
ymin = (std::min)(ymin,y1);
ymin = (std::min)(ymin,y2);
}
out << "%!PS-Adobe-2.0 EPSF-2.0" << std::endl;
out << "%%BoundingBox: " << int(xmin+0.5) << " "
<< int(ymin+0.5) << " "
<< int(xmax+0.5) << " "
<< int(ymax+0.5) << std::endl;
out << "%%HiResBoundingBox: " << xmin << " "
<< ymin << " "
<< xmax << " "
<< ymax << std::endl;
out << "%%EndComments" << std::endl;
out << "gsave" << std::endl;
out << "0.1 setlinewidth" << std::endl;
// color macros
out << std::endl;
out << "% RGB color command - r g b C" << std::endl;
out << "/C { setrgbcolor } bind def" << std::endl;
out << "/white { 1 1 1 C } bind def" << std::endl;
out << "/black { 0 0 0 C } bind def" << std::endl;
// edge macro -> E
out << std::endl;
out << "% Black stroke - x1 y1 x2 y2 E" << std::endl;
out << "/E {moveto lineto stroke} bind def" << std::endl;
out << "black" << std::endl << std::endl;
// for each halfedge
for (pHalfedge = mesh.halfedges_begin();
pHalfedge != mesh.halfedges_end();
pHalfedge++)
{
double x1 = scale * mesh_adaptor.info(pHalfedge->prev())->uv().x();
double y1 = scale * mesh_adaptor.info(pHalfedge->prev())->uv().y();
double x2 = scale * mesh_adaptor.info(pHalfedge)->uv().x();
double y2 = scale * mesh_adaptor.info(pHalfedge)->uv().y();
out << x1 << " " << y1 << " " << x2 << " " << y2 << " E" << std::endl;
}
/* Emit EPS trailer. */
out << "grestore" << std::endl;
out << std::endl;
out << "showpage" << std::endl;
return true;
}
// ----------------------------------------------------------------------------
// main()
// ----------------------------------------------------------------------------
int main(int argc, char * argv[])
{
std::cerr << "PARAMETERIZATION" << std::endl;
std::cerr << " Discrete Authalic Parameterization" << std::endl;
std::cerr << " Square border" << std::endl;
std::cerr << " Eigen solver" << std::endl;
std::cerr << " Very simple cut if model is not a topological disk" << std::endl;
std::cerr << " Output: EPS" << std::endl;
//***************************************
// decode parameters
//***************************************
if (argc-1 != 2)
{
std::cerr << "Usage: " << argv[0] << " input_file.off output_file.eps" << std::endl;
return(EXIT_FAILURE);
}
// File names are:
const char* input_filename = argv[1];
const char* output_filename = argv[2];
//***************************************
// Read the mesh
//***************************************
// Read the mesh
std::ifstream stream(input_filename);
Polyhedron mesh;
stream >> mesh;
if(!stream || !mesh.is_valid() || mesh.empty())
{
std::cerr << "Error: cannot read OFF file " << input_filename << std::endl;
return EXIT_FAILURE;
}
//***************************************
// Create Polyhedron adaptor
//***************************************
Parameterization_polyhedron_adaptor mesh_adaptor(mesh);
//***************************************
// Virtually cut mesh
//***************************************
// The parameterization methods support only meshes that
// are topological disks => we need to compute a "cutting" of the mesh
// that makes it homeomorphic to a disk
Seam seam = cut_mesh(mesh_adaptor);
if (seam.empty())
{
std::cerr << "Input mesh not supported: the example cutting algorithm is too simple to cut this shape" << std::endl;
return EXIT_FAILURE;
}
// Create a second adaptor that virtually "cuts" the mesh following the 'seam' path
typedef CGAL::Parameterization_mesh_patch_3<Parameterization_polyhedron_adaptor>
Mesh_patch_polyhedron;
Mesh_patch_polyhedron mesh_patch(mesh_adaptor, seam.begin(), seam.end());
if (!mesh_patch.is_valid())
{
std::cerr << "Input mesh not supported: non manifold shape or invalid cutting" << std::endl;
return EXIT_FAILURE;
}
//***************************************
// Discrete Authalic Parameterization (square border)
// with Eigen solver
//***************************************
// Border parameterizer
typedef CGAL::Square_border_arc_length_parameterizer_3<Mesh_patch_polyhedron>
Border_parameterizer;
// Eigen solver
typedef CGAL::Eigen_solver_traits<> Solver;
// Discrete Authalic Parameterization (square border)
// with Eigen solver
typedef CGAL::Discrete_authalic_parameterizer_3<Mesh_patch_polyhedron,
Border_parameterizer,
Solver> Parameterizer;
Parameterizer::Error_code err = CGAL::parameterize(mesh_patch, Parameterizer());
switch(err) {
case Parameterizer::OK: // Success
break;
case Parameterizer::ERROR_EMPTY_MESH: // Input mesh not supported
case Parameterizer::ERROR_NON_TRIANGULAR_MESH:
case Parameterizer::ERROR_NO_TOPOLOGICAL_DISC:
case Parameterizer::ERROR_BORDER_TOO_SHORT:
std::cerr << "Input mesh not supported: " << Parameterizer::get_error_message(err) << std::endl;
return EXIT_FAILURE;
break;
default: // Error
std::cerr << "Error: " << Parameterizer::get_error_message(err) << std::endl;
return EXIT_FAILURE;
break;
};
//***************************************
// Output
//***************************************
// Write Postscript file
if ( ! write_file_eps(mesh_adaptor, output_filename) )
{
std::cerr << "Error: cannot write file " << output_filename << std::endl;
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
}