FindQt4 fails to link QtOpenGL project properly - qt

Question

Projects that use the QtOpenGL fail to link to gl calls, but only on Windows (Linux is happy). The MSVC 2008 error messages for the following minimal case project are:
1>gllink.obj : error LNK2019: unresolved external symbol __imp__glLoadIdentity#0 referenced in function "protected: virtual void __thiscall ImageWidget::initializeGL(void)" (?initializeGL#ImageWidget##MAEXXZ)
1>gllink.obj : error LNK2019: unresolved external symbol __imp__glMatrixMode#4 referenced in function "protected: virtual void __thiscall ImageWidget::initializeGL(void)" (?initializeGL#ImageWidget##MAEXXZ)
1>gllink.exe : fatal error LNK1120: 2 unresolved externals
These errors disappear when I manually add "opengl32.lib" to the "Additional Dependencies" list, but I believe this should not be necessary, since this should either be done by FindQt4.cmake, or should be taken care of by the dependency of QtOpenGL on opengl32. Of course, I must be mistaken, so I would really appreciate some input on how to properly fix this project.
gllink.cpp
#include <QtOpenGL>
#include <QWidget>
class ImageWidget : public QGLWidget
{
public:
ImageWidget(QWidget* parent = 0) :
QGLWidget(parent)
{
}
protected:
void initializeGL()
{
glMatrixMode( GL_MODELVIEW );
glLoadIdentity();
}
};
int main()
{
ImageWidget w;
return 0;
}
CMakeLists.txt
PROJECT( gllink )
CMAKE_MINIMUM_REQUIRED( VERSION 2.8 )
FIND_PACKAGE( Qt4 4.6.0 REQUIRED COMPONENTS QtCore QtGui QtOpenGL )
INCLUDE( ${QT_USE_FILE} )
ADD_EXECUTABLE( gllink gllink.cpp )
TARGET_LINK_LIBRARIES( gllink ${QT_LIBRARIES} )

Answer 1

FindQt4 doesn't take care of that, you have to search for OpenGL by yourself. Now CMake provides a FindOpenGL package, so fixing your project is just a matter of adding find_package( OpenGL ) and linking the libraries to your target:
PROJECT( gllink )
CMAKE_MINIMUM_REQUIRED( VERSION 2.8 )
FIND_PACKAGE( OpenGL )
FIND_PACKAGE( Qt4 4.6.0 REQUIRED QtCore QtGui QtOpenGL )
INCLUDE( ${QT_USE_FILE} )
ADD_EXECUTABLE( gllink gllink.cpp )
TARGET_LINK_LIBRARIES( gllink ${OPENGL_LIBRARIES} ${QT_LIBRARIES} )
Btw, you should check if those libraries are really found and warn the user about the problem if they're not :)