\( \newcommand{\E}{\mathrm{E}} \) \( \newcommand{\A}{\mathrm{A}} \) \( \newcommand{\R}{\mathrm{R}} \) \( \newcommand{\N}{\mathrm{N}} \) \( \newcommand{\Q}{\mathrm{Q}} \) \( \newcommand{\Z}{\mathrm{Z}} \) \( \def\ccSum #1#2#3{ \sum_{#1}^{#2}{#3} } \def\ccProd #1#2#3{ \sum_{#1}^{#2}{#3} }\)

CGAL 4.8 - Combinatorial Maps

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Combinatorial_map/map_3_dynamic_onmerge.cpp
#include <CGAL/Combinatorial_map.h>
#include <CGAL/Combinatorial_map_constructors.h>
#include <CGAL/Combinatorial_map_operations.h>
#include <CGAL/Cell_attribute.h>
#include <iostream>
#include <cstdlib>
// My item class: no functor is associated with Face_attribute.
struct Myitem
{
template<class CMap>
struct Dart_wrapper
{
typedef CGAL::Dart<3, CMap> Dart;
typedef CGAL::Cell_attribute<CMap, int> Face_attribute;
typedef CGAL::cpp11::tuple<void,void,Face_attribute> Attributes;
};
};
// Definition of my combinatorial map.
typedef CGAL::Combinatorial_map<3,Myitem> CMap_3;
typedef CMap_3::Dart_handle Dart_handle;
typedef CMap_3::Attribute_type<2>::type Face_attribute;
// Functor called when two faces are merged.
struct Merge_functor
{
// operator() automatically called before a merge.
void operator()(Face_attribute& ca1, Face_attribute& ca2)
{
ca1.info()=ca1.info()+ca2.info();
std::cout<<"After on merge faces: info of face1="<<ca1.info()
<<", info of face2="<<ca2.info()<<std::endl;
}
};
// Functor called when one face is split in two.
struct Split_functor
{
Split_functor(CMap_3& amap) : mmap(amap)
{}
// operator() automatically called after a split.
void operator()(Face_attribute& ca1, Face_attribute& ca2)
{
set_color_of_face(ca1.dart());
set_color_of_face(ca2.dart());
std::cout<<"After on split faces: info of face1="<<ca1.info()
<<", info of face2="<<ca2.info()<<std::endl;
}
private:
// The info of a face is the mean of the info of all its neighboors faces.
void set_color_of_face(CMap_3::Dart_handle dh)
{
int nb=0;
int sum=0;
for (CMap_3::Dart_of_orbit_range<1>::iterator
it=mmap.darts_of_orbit<1>(dh).begin(),
itend=mmap.darts_of_orbit<1>(dh).end();
it!=itend; ++it, ++nb)
{ sum+=mmap.info<2>(mmap.beta<2>(it)); }
mmap.info<2>(dh)=(sum/nb);
}
CMap_3& mmap;
};
// Function allowing to display all the 2-attributes, and the characteristics
// of a given combinatorial map.
void display_map_and_2attributes(CMap_3& cm)
{
for (CMap_3::Attribute_range<2>::type::iterator
it=cm.attributes<2>().begin(), itend=cm.attributes<2>().end();
it!=itend; ++it)
{
std::cout<<cm.info_of_attribute<2>(it)<<"; ";
}
std::cout<<std::endl;
cm.display_characteristics(std::cout);
std::cout<<", valid="<<cm.is_valid()<<std::endl;
}
int main()
{
CMap_3 cm;
// 0) Create 2 hexahedra.
Dart_handle dh1 = CGAL::make_combinatorial_hexahedron(cm);
Dart_handle dh2 = CGAL::make_combinatorial_hexahedron(cm);
// 1) Create 2-attributes of the first hexahedron, info()==7.
for (CMap_3::One_dart_per_incident_cell_range<2, 3>::iterator
it=cm.one_dart_per_incident_cell<2,3>(dh1).begin(),
itend=cm.one_dart_per_incident_cell<2,3>(dh1).end(); it!=itend; ++it)
{ cm.set_attribute<2>(it, cm.create_attribute<2>(7)); }
// 2) Create 2-attributes of the second hexahedron, info()==13.
for (CMap_3::One_dart_per_incident_cell_range<2, 3>::iterator it=
cm.one_dart_per_incident_cell<2,3>(dh2).begin(),
itend=cm.one_dart_per_incident_cell<2,3>(dh2).end(); it!=itend; ++it)
{ cm.set_attribute<2>(it, cm.create_attribute<2>(13)); }
// 3) Set the onsplit and onmerge functors.
cm.onsplit_functor<2>()=Split_functor(cm);
cm.onmerge_functor<2>()=Merge_functor();
// 4) 3-Sew the two hexahedra along one face. This calls 1 onmerge.
cm.sew<3>(dh1, dh2);
// 5) Display all the values of 2-attributes.
display_map_and_2attributes(cm);
// 6) Insert a vertex in the face between the two hexahedra.
// This calls 4 onsplit.
Dart_handle resdart=CGAL::insert_cell_0_in_cell_2(cm, dh2);
// 7) Display all the values of 2-attributes.
display_map_and_2attributes(cm);
// 8) "Remove" the dynamic onmerge functor.
cm.onmerge_functor<2>()=boost::function<void(Face_attribute&,
Face_attribute&)>();
// 9) Remove one edge: this merges two faces, however no dynamic
// functor is called (because it was removed).
CGAL::remove_cell<CMap_3, 1>(cm, resdart);
// 10) Display all the values of 2-attributes.
display_map_and_2attributes(cm);
return EXIT_SUCCESS;
}