c++linuxcmakelibigl

After `libigl` update to ver 2.4.0 I can't build anymore

My CMakeLists.txt file for my old libigl testing project contains the piece below:

project(libigl)

set(LIBIGL_HOME $ENV{HOME}/apps/libigl)
set(CMAKE_PREFIX_PATH ${LIBIGL_HOME})
set(CMAKE_MODULE_PATH ${LIBIGL_HOME}/cmake)
find_package(${PROJECT_NAME} CONFIGS libigl.cmake REQUIRED)

if(${PROJECT_NAME}_FOUND)
  message("-- Found ${PROJECT_NAME}")
else()
  message(FATAL_ERROR "${PROJECT_NAME} is not found")
endif()

I tried to build this project with the new version 2.4.0 of the libigl library and got this message:

CMake Error at /home/hekto/apps/libigl/cmake/libigl.cmake:5 (message):
  You included libigl.cmake directly from your own project.  This behavior is
  not supported anymore.  Please add libigl to your project via
  add_subdirectory(<path_to_libigl>).  See the libigl example project for
  more information: https://github.com/libigl/libigl-example-project/
Call Stack (most recent call first):
  CMakeLists.txt:43 (find_package)

So, they recommend to use the add_subdirectory command for client projects. I looked at the CMakeLists.txt file from the recommended GitHub example project and couldn't find the add_subdirectory command:

cmake_minimum_required(VERSION 3.16)
project(example)

list(PREPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake)

# Libigl
include(libigl)

# Enable the target igl::glfw
igl_include(glfw)

# Add your project files
file(GLOB SRC_FILES *.cpp)
add_executable(${PROJECT_NAME} ${SRC_FILES})
target_link_libraries(${PROJECT_NAME} PUBLIC igl::glfw)

How should I build with the new version 2.4.0 of the libigl?

Solution

  • Just to wrap up the discussion in comments - may be, this answer will help somebody...

    So, the minimal CMakeLists.txt file, which worked for me to compile a simple test, showing the "bunny" mesh, is below:

    cmake_minimum_required(VERSION 3.10)

project(bunny)

set(CMAKE_PREFIX_PATH $ENV{HOME}/apps/CGAL/current)
find_package(CGAL CONFIG REQUIRED)

add_subdirectory($ENV{HOME}/apps/libigl/current ${CMAKE_BINARY_DIR}/libigl)

igl_include(copyleft cgal)
igl_include(glfw)

add_executable(${PROJECT_NAME} ${PROJECT_NAME}.cpp)
target_link_libraries(${PROJECT_NAME} CGAL::CGAL igl::core igl::glfw)

    You can see here, that both CGAL and libigl libraries are installed in my home directory. The CGAL version is 6.0.1, the libigl is 2.4.0. If you have these libraries in system directories, then the CMakeLists.txt file will be even simpler. The source bunny.cpp is below:

    #include <Eigen/Dense>

#include <igl/read_triangle_mesh.h>
#include <igl/opengl/glfw/Viewer.h>

int main()
{
  Eigen::MatrixXd V;
  Eigen::MatrixXi F;
  // ------ load a mesh
  igl::read_triangle_mesh("data/bunny.off", V, F);
  // ------ plot the mesh
  igl::opengl::glfw::Viewer viewer;
  viewer.data().set_mesh(V, F);
  viewer.launch();
}

    Good luck with the libigl!