How to compile GLUT + OpenGL project with CMake an

问题:

As the titles says I can't seem to build the project with OpenGL and Glut.

I get Undefined reference errors for OpenGL functions.

I tried doing :

project(testas)
find_package(OpenGL)
find_package(GLUT)
add_executable(testas main.cpp)

But that doesn't work.

Any suggestions?

回答1:

find_package(OpenGL) will find the package for you, but it doesn't link the package to the target.

To link to a library, you can use target_link_libraries(<target> <item>). In addition, you also need to set the include directory, so that the linker knows where to look for things. This is done with the include_directories.

An example CMakeLists.txt which would do this looks something like this:

cmake_minimum_required(VERSION 2.8)

project(testas)
add_executable(testas main.cpp)
find_package(OpenGL REQUIRED)
find_package(GLUT REQUIRED)
include_directories( ${OPENGL_INCLUDE_DIRS}  ${GLUT_INCLUDE_DIRS} )

target_link_libraries(testas ${OPENGL_LIBRARIES} ${GLUT_LIBRARY} )

If OpenGL is a necessity for your project, you might consider either testing OpenGL_FOUND after the find_package(OpenGL) or using REQUIRED, which will stop cmake if OpenGL is not found.

For more information and better examples:

• CMake 2.8 documentation, target_link_libraries
• CMake 2.8 documentation, find_package
• CMake wiki: how to find libraries
• Forum post with solution: cmake and opengl
• Tutorial for CMake by swarthmore.edu

In particular, the CMake wiki and cmake and opengl links should give you enough to get things working.

回答2:

In recent versions of CMake (3.10+) there is a new way to use OpenGL using a so-called IMPORTED target:

cmake_minimum_required(VERSION 3.10)

project(testas)
add_executable(testas main.cpp)
find_package(OpenGL REQUIRED COMPONENTS OpenGL)
find_package(GLUT REQUIRED)

add_dependencies(testas OpenGL::OpenGL)
include_directories(${GLUT_INCLUDE_DIRS} )

target_link_libraries(testas OpenGL::OpenGL ${GLUT_LIBRARY} )

At the moment the only practical difference seems to be on Linux (where GLVND is used if available), but presumably this solution should be more future-proof, as CMake has more information about your intentions and other tools parsing your CMakeFiles will better understand the dependency tree.

回答3:

I use these two cmake files to build my OpenGL projects, and they all work well.

I only test these two cmake files under Deepin Linux. Deepin Linux is a Chinese grown Linux system like Ubuntu or from Debian.

First, the main CMakeLists.txt

cmake_minimum_required(VERSION 3.1.0)
project(project_name)

set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_CURRENT_SOURCE_DIR}/CMakeModules/")

find_package(OpenGL REQUIRED)
find_package(FREEGLUT REQUIRED)
find_package(GLEW REQUIRED)

if(NOT ${OPENGL_FOUND})
    message("OPENGL not found")
endif()

include_directories(
    ${PROJECT_SOURCE_DIR}
    ${FREEGLUT_INCLUDE_DIR}
    ${GLEW_INCLUDE_DIR}
    ${OPENGL_INCLUDE_DIR}
    )

message(${OPENGL_INCLUDE_DIR})
add_executable(${PROJECT_NAME}  ${PROJECT_SOURCE_DIR}/filename.cpp) 
target_link_libraries(${PROJECT_NAME} 
${OPENGL_LIBRARY}
${FREEGLUT_LIBRARY}
${GLEW_LIBRARY}
)

Second, the find GLUT cmake file under CMakeModules directory

# Try to find the FREEGLUT library
#
# FREEGLUT_INCLUDE_DIR
# FREEGLUT_LIBRARY
# FREEGLUT_FOUND

FIND_PATH(
  FREEGLUT_INCLUDE_DIR GL/freeglut.h GL/gl.h GL/glu.h GL/glew.h
  ${CMAKE_INCLUDE_PATH}
  $ENV{include}
  ${OPENGL_INCLUDE_DIR}
  /usr/include
  /usr/local/include
)

SET(STORE_CMAKE_FIND_FRAMEWORK ${CMAKE_FIND_FRAMEWORK})
SET(CMAKE_FIND_FRAMEWORK NEVER)

FIND_LIBRARY(
  FREEGLUT_LIBRARY
  NAMES freeglut_static freeglut glut GL
  PATH
    /opt/local/lib
    ${CMAKE_LIBRARY_PATH}
    $ENV{lib}
    /usr/lib
    /usr/local/lib
)

SET(CMAKE_FIND_FRAMEWORK ${STORE_CMAKE_FIND_FRAMEWORK})

IF (FREEGLUT_INCLUDE_DIR AND FREEGLUT_LIBRARY)
   SET(FREEGLUT_FOUND TRUE)
ENDIF (FREEGLUT_INCLUDE_DIR AND FREEGLUT_LIBRARY)

IF (FREEGLUT_FOUND)
   IF (NOT FREEGLUT_FIND_QUIETLY)
      MESSAGE(STATUS "Found FREEGLUT: ${FREEGLUT_LIBRARY}")
   ENDIF (NOT FREEGLUT_FIND_QUIETLY)
ELSE (FREEGLUT_FOUND)
   IF (FREEGLUT_FIND_REQUIRED)
      MESSAGE(FATAL_ERROR "Could not find FREEGLUT")
   ENDIF (FREEGLUT_FIND_REQUIRED)
ENDIF (FREEGLUT_FOUND)