[Interest] compiling qt with eglfs

[pritam.ghanghas at gmail.com]

On Thu, Nov 8, 2012 at 5:32 PM, pritam.ghanghas at gmail.com <
pritam.ghanghas at gmail.com> wrote:

>
>
> On Wed, Nov 7, 2012 at 10:50 PM, Thomas Senyk <thomas.senyk at pelagicore.com
> > wrote:
>
>> On Wed, November 07, 2012 06:16:39 PM pritam.ghanghas at gmail.com wrote:
>> > On Wed, Nov 7, 2012 at 5:29 PM, Thomas Senyk
>> <thomas.senyk at pelagicore.com>wrote:
>> > > On Wed, November 07, 2012 05:29:00 PM pritam.ghanghas at gmail.comwrote:
>> > > > Hi
>> > > >
>> > > > I was trying to get qt working with eglfs + opengles.
>> > > > I am able to compile but when I try to run hellogl_es2. I get this.
>> > > >
>> > > > ./hellogl_es2 -qws
>> > >
>> > > No no no! :) No! :)
>> > > I can't stretch that enough: eglfs doesn't support this application!
>> > >
>> > > Those plugins (eglfs, simplegl, minimalegl, kms,...) only support
>> one(!)
>> > > fullscreen opengl-surface..
>> > > Therefor one can't mix QWidget-classes with QGLWidget (as it's the
>> case
>> > > for
>> > > hellogl_es2)
>> > >
>> > > How do I get the mix(QWidget + some QGLWidgets) working then? I need
>> the
>> >
>> > mix. I have a lot of
>> > code that is in QWidgets and I would like to use QGLWIdget incremently
>> as
>> > and when I need it.
>> > I was previously using directfb. I enabled opengl without changing
>> anything
>> > else, hellogl_es2 lauched
>> > but glWidget showed nothing, just some garbage probably due to not
>> clearing
>> > the surface.
>> > So I swtiched to eglfs that resulted in the current scenario.
>>
>> This is a hard limitation of eglfs.
>> It can't handle/composit multiple egl-surfaces and as the QGLWidget needs
>> a
>> egl-surface and you also having QWidgets around the QGLWidget which also
>> need
>> a surface you can forget about eglfs.
>>
>>
>> You need a proper windowing system for that kind of approach.
>> The 3 I know of:
>> - X11       (not embedded)
>> - directfb (not clue about the current state of the different directfb
>> pluings)
>> - wayland (properly not available on your board)
>>
>>
>>
>> Another long-term solution would be to switch to QtQuick(2.0)   ;)
>>
>
> Thank you for great explanation. We would switch to QtQuick ultimately.
> But for now I need to see opengl performance. I have not yet reached to
> the point where I get
> a simple gl application running.
>
>
>>
>> >
>> > > Take qmlviewer or similar and use QGLWidget as viewport for the
>> > > QGraphicsView/QDeclarativeView
>> > > (-opengl as argument for qmlviewer)
>> > >
>> > > > QScreenLinuxFb::connect: No such file or directory
>> > > > Error opening framebuffer device /dev/fb0
>> > > >
>> > > > : driver cannot connect
>> > > >
>> > > > Aborted
>> > > >
>> > > > I don't understand why it needs  /dev/fb0.
>> > >
>> > > QWS != QPA
>> > >
>> > > They are different, independent Qt ports.
>> > > They can't co-exist! You have to take one or the other!
>> > >
>> > >
>> > > eglfs is a platform plugin for QPA
>> > > Their is simplegl for QWS, but I got no clue about it's current state.
>> > >
>> > > Me advice is to try QPA and eglfs as I know it's working.
>> >
>> > So if I supply -qpa while configuring qt and copy my mkspec from qws to
>> qpa
>> > dir, will i get working QPA?
>>
>> Yes most likely!
>>  ... as long as you keep in mind that the plugins are also two distinct
>> sets!
>> One set of plugins for QWS
>> Another set of plugins for QPA
>>
>> >
>> > > > Any Ideas what is wrong. This is with Qt 4.8.3.
>> > > > configure argument and output can be found here.
>> > > > http://pastebin.kde.org/598940/
>> > > >
>> > > > I am comiling qt5 in parallel but results from that will take some
>> time.
>> > > > Any ideas what is going wrong here.
>> > >
>> > > You will not have that problem with qt5, as qws is gone ;)
>> > >
>> > > great, lesser confusion :-).
>>
>
>
>
> --
> pritam
>

I am still stuck with qt 4.8.3 with qpa. It always compiles, but I never
got it to work.
Now when i try the application its failing at load time itself
# ./hellogl_es2 -qpa -platform egl
Failed to load platform plugin "egl". Available platforms are:
Minimal

if I try Minimal, I get a segfault.
./hellogl_es2 -qpa -platform Minimal
Segmentation fault

backtrace from gdb shows that it crashes in
QGLContext::chooseContext(QGLContext const*) ()

I have no idea what to do next. why didn't I get eglfs plugin when I had
specified -egl in configure.

-- 
pritam
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