Rendering to a QGLWidget from a QThread - makeCurrent fails [solved]

[neobrain]

Hi there,
I'm currently writing a Qt4 GUI for an emulator and need to offload the rendering of a QGLWidget to a separate QThread. The reason for this is that since our GPU emulation is using OpenGL for rendering, we'd have to run emulation on the GUI thread, which is kinda awkward. I don't want to restructure the underlying emulator code (especially since it's supposed to be toolkit-independent) to avoid this (if that's even possible), so I figured the best way would be to leave the GUI thread as it is and let the emulation run on a separate QThread.
This article suggests that this idea should be perfectly feasible. However, when I'm trying to implement it like described in the article, I get an "QGLContext::makeCurrent(): Failed." error whenever I'm calling glwidget->makeCurrent() from the QThread (glwidget->context()->isValid() returns true though). I've tried coding a minimal application that will test the implementation, and it also outputs makeCurrent errors:

#include <QtGui>
#include <QtOpenGL>
#include <X11/Xlib.h>
 
class MyGLWidget;
class MyThread : public QThread
{
public:
    MyThread(MyGLWidget* _glw);
    void run();
 
private:
    MyGLWidget* glw;
};
 
class MyGLWidget : public QGLWidget
{
public:
    MyGLWidget(QWidget* parent = NULL);
 
    void start_rendering() { thread.start(); }
private:
    MyThread thread;
};
 
MyThread::MyThread(MyGLWidget* _glw) : glw(_glw) {}
MyGLWidget::MyGLWidget(QWidget* parent) : QGLWidget(parent), thread(this) {}
 
 
void MyThread::run()
{
    while(1) {
        glw->makeCurrent();           // error
        glClear(GL_COLOR_BUFFER_BIT);
        glw->swapBuffers();
        glw->doneCurrent();
    }
}
 
int main(int argc, char* argv[])
{
    QCoreApplication::setAttribute(Qt::AA_X11InitThreads); //  or just XInitThreads();
    QApplication app(argc, argv);
 
    QMainWindow win;
    MyGLWidget* glw = new MyGLWidget(&win);
    win.setCentralWidget(glw);
    win.show();
    glw->start_rendering();
 
    return app.exec();
}

#include <QtGui>
#include <QtOpenGL>
#include <X11/Xlib.h>

class MyGLWidget;
class MyThread : public QThread
{
public:
    MyThread(MyGLWidget* _glw);
    void run();

private:
    MyGLWidget* glw;
};

class MyGLWidget : public QGLWidget
{
public:
    MyGLWidget(QWidget* parent = NULL);

    void start_rendering() { thread.start(); }
private:
    MyThread thread;
};

MyThread::MyThread(MyGLWidget* _glw) : glw(_glw) {}
MyGLWidget::MyGLWidget(QWidget* parent) : QGLWidget(parent), thread(this) {}


void MyThread::run()
{
    while(1) {
        glw->makeCurrent();           // error
        glClear(GL_COLOR_BUFFER_BIT);
        glw->swapBuffers();
        glw->doneCurrent();
    }
}

int main(int argc, char* argv[])
{
    QCoreApplication::setAttribute(Qt::AA_X11InitThreads); //  or just XInitThreads();
    QApplication app(argc, argv);

    QMainWindow win;
    MyGLWidget* glw = new MyGLWidget(&win);
    win.setCentralWidget(glw);
    win.show();
    glw->start_rendering();

    return app.exec();
}

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Note that I'm running this on an openSUSE Linux system right now. I haven't had a chance to test it on a Windows machine, yet, but will do so once I get a chance.

Anyway, I would be REALLY thankful if anyone could help me out with this one, I've spent so many hours on this already without finding a solution. Thanks in advance!