\( \newcommand{\E}{\mathrm{E}} \) \( \newcommand{\A}{\mathrm{A}} \) \( \newcommand{\R}{\mathrm{R}} \) \( \newcommand{\N}{\mathrm{N}} \) \( \newcommand{\Q}{\mathrm{Q}} \) \( \newcommand{\Z}{\mathrm{Z}} \) \( \def\ccSum #1#2#3{ \sum_{#1}^{#2}{#3} } \def\ccProd #1#2#3{ \sum_{#1}^{#2}{#3} }\)
CGAL 4.12.1 - Linear Cell Complex
Linear_cell_complex/linear_cell_complex_3_attributes_management.cpp
#include <CGAL/Linear_cell_complex_for_combinatorial_map.h>
#include <CGAL/Linear_cell_complex_constructors.h>
#include <CGAL/Timer.h>
#include <iostream>
#include <fstream>
typedef LCC_3::Dart_handle Dart_handle;
typedef LCC_3::Point Point;
typedef LCC_3::FT FT;
void load_and_simplify_off(LCC_3& lcc, const std::string& filename,
bool updateattribs, int percent)
{
std::ifstream ifile(filename.c_str());
if (ifile)
{
CGAL::load_off(lcc, ifile);
CGAL::Timer timer;
Dart_handle dh;
std::size_t nb=(lcc.number_of_darts()*percent)/200;
timer.start();
if (!updateattribs) lcc.set_automatic_attributes_management(false);
for (LCC_3::Dart_range::iterator it=lcc.darts().begin(),
itend=lcc.darts().end(); it!=itend && nb>0; )
{
dh=it++;
if ( it!=itend && it==lcc.beta<2>(dh) ) ++it;
lcc.remove_cell<1>(dh);
--nb;
}
if ( !updateattribs ) lcc.set_automatic_attributes_management(true);
timer.stop();
lcc.display_characteristics(std::cout);
std::cout<<", valid="<< lcc.is_valid()
<<" time: "<<timer.time()<<" seconds." << std::endl;
}
}
int main(int narg, char** argv)
{
if (narg>1 && (!strcmp(argv[1],"-h") || !strcmp(argv[1],"-?")) )
{
std::cout<<"Usage: a.out file.off [percentage]"<<std::endl;
return EXIT_FAILURE;
}
std::string filename;
if ( narg==1 )
{
filename=std::string("data/armadillo.off");
std::cout<<"No filename given: use data/armadillo.off by default."<<std::endl;
}
else filename=std::string(argv[1]);
int percent = 30; // remove 30 percent of edges
if ( narg>2 ) { percent = atoi(argv[2]); }
std::cout<<percent<<"% edges to remove."<<std::endl;
LCC_3 lcc;
std::cout<<"Update attribute DURING operations: ";
load_and_simplify_off(lcc, filename, true, percent);
LCC_3 lcc2;
std::cout<<"Update attribute AFTER operations: ";
load_and_simplify_off(lcc2, filename, false, percent);
return EXIT_SUCCESS;
}