[Interest] Display issue with Qt application over SSH/X11

[charlie hemlock]

Hello,
Thank you for replying Thiago.

Yes, I can display glxgears over ssh/x11 - not optimal, but at least
displays. (gears turn really slow, and framerate reported is high (~1000
FPS)

> Can you switch back to Mesa from the Nvidia drivers and try that?
I'm not exactly sure how to do that w/o uninstall of Nvidia drivers, or are
there some run-time setting changes just for the app?

setting LIBGL_ALWAYS_SOFTWARE=1.
didn't help.  (but believe expected since Nvidia drivers used)

However:
I have tried spyder and the other pyqt5/examples/opengl/ on another server
(CentOS 7, w/o Nvidia drivers)  and also have problems.
Though the app **doesn't display at all** in most cases . But some cases it
does appear but is so slow it is unusable.
(glxgears will display).    More details below.

For example, VcXsrv has a default setting called "Native opengl"
"Use the native windows opengl library (wgl). Make sure to export the
LIBGL_ALWAYS_INDIRECT environment variable".  This defaults setting seems
to work fine for several apps, and I believe is preferred.

Its these newer qt5 apps with opengl that appear to be problematic.
Between qt 5.6 and 5.9 something changed.

Previously spyder used qt4, and I had improved responsiveness when I set
QT_GRAPHICSSYTEM=native
Though I believe that environment variable is deprecated in qt5.  (see
links in original message)


Results below:

VcXsrv Native openGL = on (default, checked)
#Result#: Fails. Does not appear. Have to kill processes.
libGL error: No matching fbConfigs or visuals found
libGL error: failed to load driver: swrast
QQuickWidget: Failed to make context current
QQuickWidget::resizeEvent() no OpenGL context

VcXsrv Native openGL = on
LIBGL_ALWAYS_SOFTWARE=1
LIBGL_ALWAYS_INDIRECT=1
#Result#: Fails. Does not appear. Have to kill processes.
QQuickWidget: Failed to make context current
QQuickWidget::resizeEvent() no OpenGL context

VcXsrv Native openGL = on
LIBGL_ALWAYS_SOFTWARE=1
#Result#: Fails. Does not appear. Have to kill processes.
libGL error: No matching fbConfigs or visuals found
libGL error: failed to load driver: swrast
QQuickWidget: Failed to make context current
QQuickWidget::resizeEvent() no OpenGL context


VcXsrv Native openGL = on
LIBGL_ALWAYS_INDIRECT=1
#Result#: Fails. Does not appear. Have to kill processes.
QQuickWidget: Failed to make context current
QQuickWidget::resizeEvent() no OpenGL context

VcXsrv Native openGL = off
LIBGL_ALWAYS_SOFTWARE=1
#Result#: appears ok. responsive = very slow, unusable

VcXsrv Native openGL = off
LIBGL_ALWAYS_INDIRECT=1
#Result#: SegFault  (expected issues w/this)

VcXsrv Native openGL = off
#Result#: appears ok. responsive = very slow, unusable


Thanks!


On Mon, Jul 16, 2018 at 9:09 PM, Thiago Macieira <thiago.macieira at intel.com>
wrote:

> On Monday, 16 July 2018 16:47:55 PDT charlie hemlock wrote:
> > % spyder
> > QQuickWidget: Failed to make context current
> > QQuickWidget::resizeEvent() no OpenGL context
> > QQuickWidget: Failed to make context current
> > QQuickWidget: Failed to make context current
> > QQuickWidget::resizeEvent() no OpenGL context
> > QQuickWidget: Failed to make context current
> > QQuickWidget: Attempted to render scene with no context
> > QQuickWidget: Attempted to render scene with no context
> > composeAndFlush: makeCurrent() failed
>
> Yep, definitely OpenGL issues.
>
> Please make sure glxgears works before trying a Qt application.
>
> Can you switch back to Mesa from the NVidia drivers and try that? If that
> isn't enough, try setting LIBGL_ALWAYS_SOFTWARE=1.
>
> > Using Windows 10, PuTTY, VcXsrv, and the PyQt apps are on a Linux
> OpenSUSE
> > 42.3 host (nVidia drivers).
>
> On OpenSUSE, the GL libraries are indirected through libglvnd. I don't
> know
> how to tell it to load the Mesa raster instead of the NVidia drivers.
>
> --
> Thiago Macieira - thiago.macieira (AT) intel.com
>   Software Architect - Intel Open Source Technology Center
>
>
>
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