Qt6 OpenGL Static Release. Error: qopenglpaintengine.cpp:-1: error: undefined reference to `__imp_glMatrixMode'

[fxr65]

@8Observer8 I think you should get opengl32.lib for linker instead of dll. The dll for runtime depends on your app. In case your app is 32bit the dll is in syswow64 and for a 64bit app the dll is in system32. But you do not have to copy the dlls, as all system folders are in path.

[8Observer8]

@fxr65 said in Qt6 OpenGL Static Release. Error: qopenglpaintengine.cpp:-1: error: undefined reference to `__imp_glMatrixMode':

I think you should get opengl32.lib for linker instead of dll.

In my case it must be "libopengl.a" because I use MinGW instead of MSVC. But where to find "libopengl.a"? Why does my example work for dynamic Qt and it does not work for static Qt?

[fxr65]

@8Observer8 I use also mingw for compilation on a W10. Last week I also struggled to get a library recognized by the linker. After setting L and l it worked. libopengl.a is on linux systems, but as you are on W10 you need opengl32.lib. You can find the lib inside the windows sdk.
See https://stackoverflow.com/questions/22231740/opengl32-lib-not-linking-properly

[8Observer8]

@fxr65 said in Qt6 OpenGL Static Release. Error: qopenglpaintengine.cpp:-1: error: undefined reference to `__imp_glMatrixMode':

libopengl.a is on linux systems, but as you are on W10 you need opengl32.lib

I thought that MinGW uses the .a extension only. It compiles all libraries to '.a'. I tried to find libopengl32.a here C:\Qt6\6.2.0\mingw81_64\lib but I didn't find it.

@fxr65 I found OpenGL32.lib in this folder: C:\Program Files (x86)\Windows Kits\10\Lib\10.0.19041.0\um\x64:

I copied it to my project directory:

But it doesn't work:

QtStaticOpenGL.pro

QT += core gui openglwidgets

win32: LIBS += -L$$PWD -lopengl32

CONFIG += c++11

SOURCES += \
    main.cpp

main.cpp

#include <QtWidgets/QApplication>
#include <QtOpenGLWidgets/QOpenGLWidget>
#include <QtGui/QOpenGLFunctions>

class Widget : public QOpenGLWidget, QOpenGLFunctions
{
private:
    void initializeGL() override
    {
        initializeOpenGLFunctions();
        glClearColor(0.3f, 0.3f, 0.3f, 1.f);
    }

    void paintGL() override
    {
        glClear(GL_COLOR_BUFFER_BIT);
    }
};

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Widget w;
    w.show();
    return a.exec();
}

[fxr65]

On my Qt 5.12 this compiles, links and runs:
opengl.pro

QT += core gui widgets

win32: LIBS += -L$$PWD -lopengl32

CONFIG += c++11

SOURCES += \
    main.cpp

main.cpp

#include <QtWidgets/QApplication.h>
#include <QtWidgets/QOpenGLWidget.h>
#include <QtGui/QOpenGLFunctions.h>

class Widget : public QOpenGLWidget, QOpenGLFunctions
{
private:
    void initializeGL() override
    {
        initializeOpenGLFunctions();
        glClearColor(0.3f, 0.3f, 0.3f, 1.f);
    }

    void paintGL() override
    {
        glClear(GL_COLOR_BUFFER_BIT);
    }
};

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Widget w;
    w.show();
    return a.exec();
}

Also this compiles, links and runs:
opengl2.pro

QT += core gui widgets

win32:

CONFIG += c++11

SOURCES += \
    main.cpp \
    widget.cpp

HEADERS += \
  widget.h

widget.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QtWidgets/QOpenGLWidget>
#include <QtGui/QOpenGLFunctions>

class Widget : public QOpenGLWidget, protected QOpenGLFunctions
{
    Q_OBJECT

public:
    Widget(QWidget *parent = nullptr);
    ~Widget();

private:
    void initializeGL() override;
    void paintGL() override;
    void resizeGL(int w, int h) override;
};
#endif // WIDGET_H

widget.cpp

#include "widget.h"

Widget::Widget(QWidget *parent)
    : QOpenGLWidget(parent)
{
    resize(500, 500);
    setWindowTitle("Qt6 C++, OpenGL ES 2.0");
}

Widget::~Widget()
{
}

void Widget::initializeGL()
{
    initializeOpenGLFunctions();
    glClearColor(0.2f, 0.2f, 0.2f, 1.0f);
}

void Widget::paintGL()
{
    glClear(GL_COLOR_BUFFER_BIT);
}

void Widget::resizeGL(int w, int h)
{
    glViewport(0, 0, w, h);
}

main.cpp

#include "Widget.h"

#include <QtWidgets/QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Widget w;
    w.show();
    return a.exec();
}

[8Observer8]

@fxr65 said in Qt6 OpenGL Static Release. Error: qopenglpaintengine.cpp:-1: error: undefined reference to `__imp_glMatrixMode':

On my Qt 5.12 this compiles, links and runs

Yes, Qt 5.15.2 Static works for me too. The problem is only with Qt 6.2.0

[fxr65]

@8Observer8 It seems I can't assist further as it compiles, links and runs on my 6.3.1. The second sample opengl2 did also compile and run after adding "win32: LIBS += -L$$PWD -lopengl32".

[JonB]

@8Observer8
Since @fxr65 says it all works under 6.3.1 the first thing would be for you check whether that does work for you too. That should clarify whether it is a Qt issue or an individual build issue.

[8Observer8]

Okay, later maybe I will try to build latest Qt with the same configuration options as for Qt 6.2.0. But that might happen in a few months or next year because building with dynamic dlls is now preferred for me because it doesn't violate the LGPL license the way it makes building Qt static. Perhaps I will do it for the experiment, but I will not use a static assembly, so as not to violate the LGPL license.

[JonB]

@8Observer8
Then why can't you just give up on static now and go with the dynamic which you say already works and doesn't have all this heartache...? Anyway, up to you.

[8Observer8]

@JonB said in Qt6 OpenGL Static Release. Error: qopenglpaintengine.cpp:-1: error: undefined reference to `__imp_glMatrixMode':

Then why can't you just give up on static now and go with the dynamic which you say already works and doesn't have all this heartache...?

I already did it. I just leave here the links to the installed Qt 6.2.0 and the static build for it:

• Qt6.2.0_MinGW_8.1.0_64bit.zip (942 MB)
• Qt6.2.0_Static.zip (194)

But be aware that using static Qt violates the LGPL license. You can use static Qt under the GPL license, but you must disclose the source code for your product, or for a commercial Qt license.

[PythonDuncan]

I also had this issue today, I followed https://medium.com/swlh/setting-opengl-for-windows-d0b45062caf to install opengl/glew/freeglut and added win32: LIBS += -lfreeglut -lglew32 -lopengl32 in the .pro file. Now everything is working.
PS, I strongly recommend to install libs via https://www.msys2.org/. It's quite simple and convenient.