Qt 5.0.1 and glext.h

  • Hi,

    Newbie here, and evaluating QT with a view to deploying it company-wide for app development, including for ios. I am aware that the ios side of QT is some time off, and willing to wait if QT works well on Windows.

    However, I have :

    #include <GL/gl.h>
    #include <GL/glext.h>
    #include <GL/glu.h>

    with the error message :

    fatal error C1083: Cannot open include file: 'GL/glext.h': No such file or directory

    No combination of also including, or substituting <QtOpenGL>, <QGLFormat>, etc seem to work, instead generating over a hundred errors.

    Any advice would be much appreciated.

  • Lifetime Qt Champion

    Hi and welcome to devnet,

    You might be missing the "glew":http://glew.sourceforge.net/ library

    Forgot to ask, which version of Qt did you download ?

    As a side note it's Qt, QT stands for Apple's QuickTime :)

  • Hi,

    I stand corrected. Qt it is then.
    What did I download ? Qt 5.0.2 64bit for desktop (MSVC2012)

    Trying to port a 4.8 project on Unix built by my colleague, to my 5.0.2 on windows, and suspect the problem is that he has used legacy opengl.

  • Lifetime Qt Champion

    What could be the most simple is to try Qt 5.1.

    IIRC, there should have been some patches that remove the needs for glew

    Hope it helps

  • Thanks. Well, I'm just evaluating it with a view to a commercial multi-seat licence, so interested if it is a configuration issue or a simple workaround. Having used many other development packages over the years to develop a variety of apps, I am somewhat disappointed with our experience of Qt to date.

    I'm also trying 4.8 on a Mac, so don't get me started there !

    Nevertheless, I'll persevere, who knows, could be a simple fix.

  • Lifetime Qt Champion

    On my side, I've been developing with Qt since the version 3 days without major problems.

    Currently on Windows and OS X with the 4.8.X series and it's going quite well. So if you encounter some problem I might be able to help

  • Thank you for your offer. Seems to be up and running on Mac, after having downloaded multi-Gb to update the OS and update xcode.

    Qt Demo examples compile and run, but a ported project is failing to find GL/gl.h, GL/glext.h, etc.

  • Lifetime Qt Champion

    Do you have QT += opengl in your pro file ?

  • Yes, most certainly

  • Lifetime Qt Champion

    Is it a simple project ? (Meaning one pro file for all)

    If not check that every other project that uses these class also includes opengl

  • It is one pro file only.

    I now notice that, if I try #include <QtOpenGL>, I get "library not found for -IGLU", if that helps.

  • Lifetime Qt Champion

    I think I found out the first problem (must be sleepy to have been so long...):

    on mac you have to:

    @#include <OpenGL/gl.h>@

    That is: framework_name/filename.h

    You can surround that with

    @#ifdef Q_OS_MACX
    #include <OpenGL/gl.h>
    #include <GL/gl.h>

  • Thank you. That seems to have fixed it.

    Now builds with no errors.

    The app runs perfectly. Brilliant. You've made my day.

  • Lifetime Qt Champion

    You're welcome !

    Don't forget to update your thread's title to solved so other forum users may know that a solution has been found :)

  • well, the original QT 5 on Windows and glext.h problem isn't solved....

  • Lifetime Qt Champion

    IIRC, there's no glext.h by default on windows. But you can get the file "here":http://www.opengl.org/registry/

  • Got the file thanks. Throwing up an error, but that may be down to internal programming, so will look into that and report back.....

  • Seems that trying to use glext.h throws up dozens of errors, and it's simply too much of a pain to sort this. I have to conclude that legacy opengl cannot be used with Qt 5.
    Tried reverting to Qt Creator 2.7.1 and Qt 4.8.4 on Windows, but this just refuses to configure a project, and ignores anything set up in the kit options.
    Qt 4.8 seems to be fine on Mac and a unix box, but Qt 5 has too many problems for us to think about using it as a future ipad app tool. If it has too many problems on Windows, it gives us no confidence that it will be safe for ios development.

  • Lifetime Qt Champion

    There must be a glitch in QtCreator's configuration.
    4.8.4 works pretty well on windows (even custom builds)

    Depending on your problem, you might consider contacting Digia to sort things out

Log in to reply

Looks like your connection to Qt Forum was lost, please wait while we try to reconnect.