Opengl with cmake

[dyeray]

Hi, I have a problem trying to compile a small application that uses QtOpenGL with CMake. Here are the CMake files:

@project(tracking-example)
cmake_minimum_required(VERSION 2.8)
find_package(Qt4 REQUIRED)
find_package(OpenCV REQUIRED)
add_definitions(${QT_DEFINITIONS})
include_directories(${QT_INCLUDES})
add_subdirectory(src)@

and:

@set(tracking-example_SRCS
main.cpp
MainWindow.cpp
glwidget.cpp
)
set(QT_USE_QTOPENGL TRUE)
INCLUDE (${QT_USE_FILE})
qt4_wrap_cpp(tracking-example_SRCS MainWindow.h)
add_executable(tracking-example ${tracking-example_SRCS})
target_link_libraries(tracking-example ${OpenCV_LIBS} ${QT_QTCORE_LIBRARY} ${QT_QTGUI_LIBRARY} ${QT_LIBRARIES})@

This is the command make generates and its output (the relevant part):

@cd /home/dyeray/pfc/tracking-example/build/src && /usr/bin/cmake -E cmake_link_script CMakeFiles/tracking-example.dir/link.txt --verbose=1
/usr/bin/c++ CMakeFiles/tracking-example.dir/main.cpp.o CMakeFiles/tracking-example.dir/MainWindow.cpp.o CMakeFiles/tracking-example.dir/glwidget.cpp.o CMakeFiles/tracking-example.dir/moc_MainWindow.cxx.o -o tracking-example -rdynamic -L/usr/lib64/lib64 -lopencv_gpu -lopencv_contrib -lopencv_legacy -lopencv_objdetect -lopencv_calib3d -lopencv_features2d -lopencv_video -lopencv_highgui -lopencv_ml -lopencv_imgproc -lopencv_flann -lopencv_core -lQtCore -lQtGui -lQtOpenGL -lQtGui -lQtCore -lQtOpenGL -Wl,-rpath,/usr/lib64/lib64
/usr/bin/ld: CMakeFiles/tracking-example.dir/glwidget.cpp.o: undefined reference to symbol 'glMatrixMode'
/usr/bin/ld: note: 'glMatrixMode' is defined in DSO /lib64/libGL.so.1 so try adding it to the linker command line
/lib64/libGL.so.1: could not read symbols: Invalid operation
collect2: error: ld returned 1 exit status@

As you see, linking to qtopengl is not enough to detect the opengl functions like glMatrixMode. If I add to target_link_libraries GL GLU then the output is:

@/usr/bin/c++ CMakeFiles/tracking-example.dir/main.cpp.o CMakeFiles/tracking-example.dir/MainWindow.cpp.o CMakeFiles/tracking-example.dir/glwidget.cpp.o CMakeFiles/tracking-example.dir/moc_MainWindow.cxx.o -o tracking-example -rdynamic -L/usr/lib64/lib64 -lopencv_gpu -lopencv_contrib -lopencv_legacy -lopencv_objdetect -lopencv_calib3d -lopencv_features2d -lopencv_video -lopencv_highgui -lopencv_ml -lopencv_imgproc -lopencv_flann -lopencv_core -lQtCore -lQtGui -lQtOpenGL -lQtGui -lQtCore -lGL -lGLU -lQtOpenGL -lGL -lGLU -Wl,-rpath,/usr/lib64/lib64
CMakeFiles/tracking-example.dir/main.cpp.o: In function GLWidget::~GLWidget()': main.cpp:(.text._ZN8GLWidgetD2Ev[_ZN8GLWidgetD5Ev]+0x13): undefined reference to vtable for GLWidget'
main.cpp:(.text._ZN8GLWidgetD2Ev[_ZN8GLWidgetD5Ev]+0x1f): undefined reference to vtable for GLWidget' CMakeFiles/tracking-example.dir/glwidget.cpp.o: In function GLWidget::GLWidget(QWidget*)':
glwidget.cpp:(.text+0x45): undefined reference to vtable for GLWidget' glwidget.cpp:(.text+0x51): undefined reference to vtable for GLWidget'
collect2: error: ld returned 1 exit status@

I don't know if GL GLU makes the error earlier (if it hides qtopengl to the linker) or if I hace to link to this and this is other error more forward in the linking.

UPDATE: Problem solved. I got the solution here: http://www.qtforum.org/article/38200/opengl-with-cmake.html