How to use QGLWidget as the viewport of a QGraphicsView and use its QGLContext afterward?

rdebroiz

Hi,

I'm trying to use a QGLWidget as the viewport of a QGraphicsView and use its QGLContext afterward.
I found a satisfactory way to do it under Linux or OSX but not with Window. My Qt version is Qt-4.8.5.

Using the following snippet :
@
QGraphicsView *graphicsView = new QGraphicsView;
QGLContext *glContext = new QGLContext(QGLFormat::defaultFormat());
QGLWidget *glWidget = new QGLWidget(glContext);
qDebug() << "1" << glContext;
glContext->makeCurrent();
qDebug() << "2" << glWidget->context();
qDebug() << "3" << QGLContext::currentContext();
graphicsView ->setViewport(glWidget);
qDebug() << "4" << glWidget->context();
qDebug() << "5" << QGLContext::currentContext();
qDebug() << "6" << glContext->isValid();
qDebug() << "7" << glWidget->context()->isValid();
@

I get as output :

*Linux:

1 0x1aba5c0
2 0x1aba5c0
3 0x1aba5c0
4 0x1aba5c0
5 0x1aba5c0
6 true
7 true

windows:

1 0x335abee8
2 0x335abee8
3 0x335abee8
4 0x335bfd70
5 0x0
6 false
7 true*

With Windows, it appears that the context I created is invalid right after calling setViewport on my QGraphicsView, then If I try to call create() or makeCurrent() on it, it end up on a crash.

I can't figure out what is happening. Is it a normal bahavior ?

Can someone higlight me what's hapening here, and what the corrrect way to proceed ?

Thanks,
rp.