Upcoming Qt switch to OpenGL ES on arm64

[Adrian Bunk]

On Wed, Nov 28, 2018 at 05:03:51PM +0300, Dmitry Shachnev wrote:
> On Tue, Nov 27, 2018 at 11:00:52PM -0800, Steve Langasek wrote:
> > $ grep-dctrl -n -sSource:Package -FDepends \
> >         -e 'libqt5(gui|3drenderer|quick|quickparticles|quickwidgets|multimediawidgets)5[[:space:]]*(\(>= 5\.[0-9.]*\))(?|$),' \
> >         /var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_xenial_*binary-amd64_Packages | sort -u
> > maliit-plugins
> > ovito
> > pyqt5
> > qml-box2d
> > qt3d-opensource-src
> > qtbase-opensource-src
> > qtdeclarative-opensource-src
> > qtubuntu-cameraplugin-fake
> > stellarium
> > wallch
> > $
> >
> > Every single other binary package that depends on libqt5gui5 (etc) in Ubuntu
> > 16.04 has an ORed dependency on libqt5gui5 | libqt5gui5-gles.
> 
> Ah, this is interesting.
> 
> The amount of packages will probably be larger in the current sid,
> but it should not be more than 20 packages.
> 
> Plus there are packages which are using QT_OPENGL_ES macro for conditional
> compilation (as I mentioned in my previous mail), but there are also not many
> of them:
> 
> gammaray
> goldendict
> gst-plugins-good1.0
> kamoso
> krita
> leocad
> openclonk
> phonon-backend-gstreamer
> qtav
> qt-gstreamer
> qtwebkit-opensource-src
> qtwayland-opensource-src
> qtcharts-opensource-src
>...

There are also packages like qmmq or kdenlive that use 
Qt5Gui_OPENGL_IMPLEMENTATION for conditional compilation.[1]

ES/non-ES is in so many places part of the Qt API that I doubt this 
could be sorted out quickly.

Qt already supports runtime ES/non-ES in the same library build on 
Windows [2], something like that might also be doable for Linux if 
anyone (Linaro? Canonical?) with a real interest in that would work
on making it happen.

Some of the listed applications already set Qt::AA_UseOpenGLES or
Qt::AA_UseDesktopOpenGL for the Windows case, but there would surely
be additional application side fixes required after someone added
dynamic OpenGL selection also for Linux to Qt.

> Dmitry Shachnev

cu
Adrian

[1] https://codesearch.debian.net/search?q=Qt5Gui_OPENGL_IMPLEMENTATION
[2] http://doc.qt.io/qt-5/windows-requirements.html#dynamically-loading-graphics-drivers

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