Upcoming Qt switch to OpenGL ES on arm64

[Lisandro Damián Nicanor Pérez Meyer]

El sábado, 24 de noviembre de 2018 11:23:51 -03 bret curtis escribió:
> Hello Lisandro!
> 
> > Yes, that's a drawback we are not hiding. Applications needing Desktop
> > OpenGL would be left out. But...
> 
> Sorry, but this is just not acceptable. There has to be another way.
> 
> > > If you say that arm64 has to be GLESv2 as well, then that is yet another
> > > arch that OpenMW can't be built for.  Before the GLESv2 switch, OpenMW
> > > worked just fine on arm* hardware, including the Raspberry Pi/Raspbian
> > > with
> > > the VC4 mesa driver that has OpenGL 2.0 support.
> > 
> > ...one thing is running and quite another is: how well does it performs
> > when doing 100% CPU-based OpenGL? Are your users *really* interested to
> > use your application when all drawing must be CPU-based?
> 
> There is a misunderstanding here and also in this thread. The Raspberry Pi
> has the VC4 GPU which is hardware accelerated Desktop OpenGL 2.1 via the
> VC4 Mesa driver.[1] This driver is fully open-source unlike the binary blob
> it comes with that only supports GLESv2, but not via X11 nor Wayland.

Ok, that's totally new for me. And indeed it changes the way (at least I) see 
things.

> So the only way to support Qt with hardware (not software) accelerated GL on
> the RPi is with the VC4 mesa driver and Desktop GL.

Point taken.

> As for OpenMW running on a RPi, it is fully hardware (GPU) accelerated via
> the VC4 driver. It runs pretty darn well. You can walk around Morrowind
> (with mods) right now at 25fps @ 1080p using a GPU-based VC4[1] OpenGL 2.0
> renderer. 60fps in interiors. This is on a Raspberry Pi 2, likely better
> with the RPi3 with VC4 being EoL, the next iteration of the RPi will likely
> be VC5/6 that is arm64.
> 
> > > I beg you, please either reverse the GLES decision in Qt or provide two
> > > separate packages for GL or GLES support.
> > 
> > I'm afraid providing two set ups is a non-go (alas, we would be doing that
> > already and avoiding all this). And I don't there are many armel/armhf
> > users with hardware Desktop OpenGL in their boards.
> 
> There are more than 5 million Raspberry Pis were sold as of February 2015.
> All of them with a VC4 GPU, Raspbian ships with the VC4 mesa driver
> enabled!
> 
> I'm of the opinion that the switch away from Desktop OpenGL to GLES was a
> huge mistake and should be reversed as soon as possible unless there is a
> way to provide for both on all archtictures.

Well, f you can prove this for armhf and/or armel, we can certainly do it.

-- 
7: Hay diferencia entre "cortar" un archivo y "borrarlo" o "eliminarlo"
    * Depende cuando se "cuelgue" Windows
    Damian Nadales
    http://mx.grulic.org.ar/lurker/message/20080307.141449.a70fb2fc.es.html

Lisandro Damián Nicanor Pérez Meyer
http://perezmeyer.com.ar/
http://perezmeyer.blogspot.com/
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