Double Buffering on QGLWidget - Background always grey

Hi,

I would like to do double buffering on QGLWidget. I already did that on QWidget and it worked perfectly. I have a QPixmap and i call a function, to draw some stuff to the pixmap.

Code:

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func()
{
     m_pixmap = QPixmap(size());
     m_pixmap.fill(this, 0, 0);
 
     QPainter painter(&m_pixmap);
     painter.setRenderHint(QPainter::Antialiasing);
     painter.initFrom(this);
     // drawing

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In my paintEvent() function I do:

Code:

---

QStylePainter painter(this);
painter.setRenderHint(QPainter::Antialiasing);
painter.drawPixmap(0, 0, m_pixmap);

---

But when I do this, my bachground is always grey. The OpenGL background is overpainted.

Any ideas why? And how can I fix this?

If I draw my objects in paintEvent directly it works. But I would like to draw the pixmap.

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Added after 23 minutes:

Solved! I had to set the QPixmap transparent.

Code:

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m_pixmap.fill(Qt::transparent);

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