CGAL 6.2 - Manual

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How to use CGAL with CMake

This page will explain how to manually create a `CMakeLists.txt` file to link a custom program with CGAL.

A base can be created using the script `cgal_create_CMakeLists`. Its usage is detailed in Section Creating a CMake Script for a Program Using CGAL.

# Linking with CGAL

To link with the CGAL library, use the following:

find_package(CGAL REQUIRED)
add_executable(my_executable my_source_file.cpp)
target_link_libraries(my_executable CGAL::CGAL)
CGAL

Other CGAL libraries are linked similarly. For example, with `CGAL_Core`:

find_package(CGAL REQUIRED COMPONENTS Core)
target_link_libraries(my_executable CGAL::CGAL CGAL::CGAL_Core)

There are also imported targets to link with CGAL dependencies that can be found in the section Compilers and Third Party Dependencies.

Note
  The CGAL targets define the following compiler flags:
  - `-frounding-math` with gcc
  - `/fp:strict /fp:except-` with MSVC

# Minimal Example Using Qt6

This section describes a minimal example of a program that uses CGAL and Qt6 for some GUI features.

## CMakeLists.txt

cmake_minimum_required(VERSION 3.12...3.31)
project(Surface_mesh_Examples)
#CGAL_Qt6 is needed for the drawing.
find_package(CGAL REQUIRED OPTIONAL_COMPONENTS Qt6)
#create the executable of the application
create_single_source_cgal_program("draw_surface_mesh.cpp")
if(CGAL_Qt6_FOUND)
#link it with the required CGAL libraries
target_link_libraries(draw_surface_mesh PRIVATE CGAL::CGAL_Basic_viewer)
endif()
#end of the file

## draw_surface_mesh.cpp

#include <CGAL/Simple_cartesian.h>
#include <CGAL/Surface_mesh.h>
#include <CGAL/draw_surface_mesh.h>
#include <fstream>
typedef CGAL::Simple_cartesian<double> Kernel;
typedef Kernel::Point_3 Point;
typedef CGAL::Surface_mesh<Point> Mesh;
int main(int argc, char* argv[])
{
const std::string filename = (argc>1) ? argv[1] : CGAL::data_file_path("meshes/elephant.off");
Mesh sm;
if(!CGAL::IO::read_polygon_mesh(filename, sm))
{
std::cerr << "Invalid input file: " << filename << std::endl;
return EXIT_FAILURE;
}
// Internal color property maps are used if they exist and are called "v:color", "e:color" and "f:color".
auto vcm = sm.add_property_map<Mesh::Vertex_index, CGAL::IO::Color>("v:color").first;
auto ecm = sm.add_property_map<Mesh::Edge_index, CGAL::IO::Color>("e:color").first;
auto fcm = sm.add_property_map<Mesh::Face_index>("f:color", CGAL::IO::white() /*default*/).first;
for(auto v : vertices(sm))
{
if(v.idx()%2)
{ put(vcm, v, CGAL::IO::black()); }
else
{ put(vcm, v, CGAL::IO::blue()); }
}
for(auto e : edges(sm))
{ put(ecm, e, CGAL::IO::gray()); }
put(fcm, *(sm.faces().begin()), CGAL::IO::red());
// Draw!
CGAL::draw(sm);
return EXIT_SUCCESS;
}
CGAL::IO::Color
CGAL::Surface_mesh
CGAL::Surface_mesh::add_property_map
std::pair< Property_map< I, T >, bool > add_property_map(std::string name=std::string(), const T t=T())
Kernel::Point_3
CGAL::IO::read_polygon_mesh
bool read_polygon_mesh(const std::string &fname, Graph &g, const NamedParameters &np=parameters::default_values())
CGAL::draw
void draw(const P &p, const GSOptions &gso)
Kernel
CGAL::Simple_cartesian