QGLWidget + QGraphicsScene + QGraphicsView problem

I would like to create a simple thumbnail viewer using QGLWidget, QGraphicsScene and QGraphicsView. And I have a problem with placing QGLWidget on QGraphicsScene. The code is similar to this:

QGraphicsScene *testScene = new QGraphicsScene (0, 0, 400, 400,开发者_运维百科 0);

QGLWidget *testWidget1 = new QGLWidget();
testWidget1->renderText("Test text1");

QGLWidget *testWidget2 = new QGLWidget();
testWidget2->renderText("Test text2");

testScene->addWidget(testWidget1);
testScene->addWidget(testWidget2);

QGraphicsView *testView = new QGraphicsView();
testView->setScene(testScene);
testView->show()

It is possible to place few QGLWidgets on QGraphicsScene/QGraphicsView? Where I doing something wrong? Is there any other component on which I could embed QGLWidgets and show them on the screen?

Thanks for help

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To make QGLWidget show in QGraphicsView, you should redirect painting for it. You can overwrite the paintGL like this:

virtual void MyGLWidget::paintGL()
{
    QGLWidget::paintGL();
    //support redirecting painting
    QPaintDevice* device = QPainter::redirected(this);
    if (device != NULL && device != this)
    {
        QImage image = grabFrameBuffer();
        QPainter painter(this);
        painter.drawImage(QPointF(0.0,0.0),image);
    }
}

It works well for most platforms, but still happens to show black widget.

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The QGraphicsScene::addWidget documentation states that QGLWidget is not a supported widget type.

Parenting a QGLWidget onto the viewport of the QGraphicsView doesn't seem to work either.

Edit:

Actually parenting a QGLWidget to the viewport does work provided I put the renderText call within the paintGL method of my test GL widget.

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From the QGraphicsView docs:

To render using OpenGL, simply call setViewport(new QGLWidget). QGraphicsView takes ownership of the viewport widget.

So, in order to draw text on the view, use a QGraphicsTextItem rather than trying to draw text using the QGLWidget.