OpenGL with Graphics View?

[olidem]

Hi!

I followed the discussion and I am very interested in being able to use OpenGL commands inside the paint() code of the items in my scene. Actually, I have started implementing this, with great success.

Here's a schematic overview of how I've done:

//...
QGraphicsScene scene;
QGraphicsView view(&scene);
//the following line adds the opengl support
view.setViewport(new QGLWidget(QGLFormat(QGL::SampleBuffers | QGL::Rgba)));
 
//here's my item class
class GLGraphicsItem : public QGraphicsItem
{
//...
void paint(QPainter *painter,	const QStyleOptionGraphicsItem *option, QWidget *widget)
{
	Q_UNUSED(option);
	Q_UNUSED(widget);
	if (painter->paintEngine()->type() != QPaintEngine::OpenGL)
	            qWarning("OpenGLScene: drawBackground needs a "
	                     "QGLWidget to be set as viewport on the "
	                     "graphics view");
	else{
		//opengl commands here
	}
}
//...
}//end-class

//...
QGraphicsScene scene;
QGraphicsView view(&scene);
//the following line adds the opengl support
view.setViewport(new QGLWidget(QGLFormat(QGL::SampleBuffers | QGL::Rgba)));

//here's my item class
class GLGraphicsItem : public QGraphicsItem
{
//...
void paint(QPainter *painter,	const QStyleOptionGraphicsItem *option, QWidget *widget)
{
	Q_UNUSED(option);
	Q_UNUSED(widget);
	if (painter->paintEngine()->type() != QPaintEngine::OpenGL)
	            qWarning("OpenGLScene: drawBackground needs a "
	                     "QGLWidget to be set as viewport on the "
	                     "graphics view");
	else{
		//opengl commands here
	}
}
//...
}//end-class

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The ablove code works nicely and does what it shoud - if I just display the view.

Now I tried to use the view function

QGraphicsView::render ( QPainter * painter, const QRectF & target = QRectF(), const QRect & source = QRect(), Qt::AspectRatioMode aspectRatioMode = Qt::KeepAspectRatio )

QGraphicsView::render ( QPainter * painter, const QRectF & target = QRectF(), const QRect & source = QRect(), Qt::AspectRatioMode aspectRatioMode = Qt::KeepAspectRatio )

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which will output the warning message, i.e. this rendering is performed *without* opengl support.

I do not need the fastest hardware acceleration for this offscreen rendering at this point, just the opengl commends are very important for me.