@skinkie said in Fully offscreen QML rendering:

Is it possible (like with a raspberry pi) to specify in the Linux cmdline directly that a certain HDMI-output must be always available, even when no screen is connected, to prevent the "No screens available" errors. Something like a non-hardware based dummy output would do too.

I can answer the first question. You can specify video=HDMI-A-1:1280x720-24@50D to force the digital output on (notice the D in the end, e will work too). My current system makes that interlaced output, so it has some particularities.

If you want interlacing in Qt, on EGLFS that would still need this bug+patch to be applied. Sadly...

For question two. Still stumbling.

Sorry I juste saw your answer, mail notification was not taken into account.
I use a dragonboard with a debian jessie and qt 5.3.2. I tried to cross compile qt 5.5 but the compilation just stops without any errors ... I've tried the same way I successed on beagleboard and raspberry but have no more time spending on this compilation so I programming directly in the board -sick- with qtcreator -re sick-
I think QQuick is part of QtQuick that seems not be available on my board :(
There is no way to get paint event of an offcreeen management in Qt ?
For now what I've done :
SubClass Widget
load an ui
Render it to a QImage that has a mapped buffer to an OpenGl buffer

My problems :
copy to the buffer is long and seems not to be asynchronous I don't understand why :(
And my widget is transparent so successive render in the same buffer don't erase (fill with trasparency) the previous exposed area :(
And even if I success creating a texture I get the problem that Qt must uses it's own OpenGL context, and I have already mine (not Qt) , so texture aren't shared

I would like, either have an automatic repaint like a QApplication byt offscreen directly il OpenGL texture :D :D :D
Or at least now where the repaint should be done to manually erase to transparent (with right coordinates :s )