CMake can't find freeglut-3.0.0

Question

Freeglut-3.0.0 is build with cmake (MinGW makefiles) and mingw and then successfully installed with mingw32-make install to C:/Program Files (x86)/freeglut.

My CMakeLists.txt is:

    cmake_minimum_required(VERSION 3.7)

    project(math_tests)

    set(TESTS_SOURCES tests.cpp gl_core_3_3.c)
    set(CMAKE_CXX_STANDARD 11)

    # GLUT
    find_package(GLUT REQUIRED)
    include_directories(${GLUT_INCLUDE_DIR})
    if(NOT GLUT_FOUND)
        message(ERROR "GLUT not found!")
    endif(NOT GLUT_FOUND)

    # OpenGL
    find_package(OpenGL REQUIRED)
    include_directories(${OpenGL_INCLUDE_DIRS})
    link_directories(${OpenGL_LIBRARY_DIRS})
    add_definitions(${OpenGL_DEFINITIONS})
    if(NOT OPENGL_FOUND)
        message(ERROR "OPENGL not found!")
    endif(NOT OPENGL_FOUND)

    add_executable(tests ${TESTS_SOURCES})
    target_link_libraries(tests math ${GLUT_LIBRARIES} ${OPENGL_LIBRARIES})

Now CMake prints error: Could NOT find GLUT (missing: GLUT_glut_LIBRARY).

I can't figure out what I am doing wrong.

Achromatous

Answer 1

Your CMakeLists.txt file statement

find_package(GLUT REQUIRED)

is going to execute this code from FindGLUT.cmake

find_library( GLUT_glut_LIBRARY NAMES glut glut32 freeglut
    PATHS
    ${OPENGL_LIBRARY_DIR}
    ${GLUT_ROOT_PATH}/Release
    )

and find_library is in your scenario unable to find any of glut glut32 freeglut libraries, because it doesn't know where they are (which for you are under C:/Program Files (x86)/freeglut).

In your case you could set ${OPENGL_LIBRARY_DIR} to the right directory, that is the one containing the freeglut.dll file, for e.g.:

set(OPENGL_LIBRARY_DIR "C:/Program Files (x86)/freeglut/lib")

given the file is under C:/Program Files (x86)/freeglut/lib directory.

Irremissible

Thanks! That worked. But how user will specify this path (since FindGLUT will require its variables instead of OPENG_LIBRARY_DIR in case it will not find GLUT)? Also, I'm building for Linux too, and CmakeLists.txt should work on both platforms. Currently it sets OPENGL_LIBRARY_DIR in if (WIN32) statement. – Achromatous

for multiplatform's sake, better to set CMAKE_PREFIX_PATH to a the parent of "lib/<freeglutlibrary>", such as "c:/program files (x86)/freeglut" in your specific scenario. Best to avoid any specific SET in your cmake, but let the end user set proper prefix with -DCMAKE_PREFIX_PATH=<your path> at configuration time. Perhaps using OPTIONS to let enduser set a specific path to freeglut would be sensible too (and the option's value would be appended to CMAKE_PREFIX_PATH by your script) – Irremissible

forgot to say that for Linux you do not need to set anything for the discovery of freeglut library, it should just work with no additional settings – Irremissible