[Mesa-users] X11 forwarding issue

Thu Mar 26 15:36:53 UTC 2020

This site gives a lot of helpful information about this topic:
http://whiteboard.ping.se/Linux/GLX

El mié., 25 de mar. de 2020 a la(s) 16:40, Pekka Paalanen (
ppaalanen at gmail.com) escribió:

> On Wed, 25 Mar 2020 15:51:19 +0100
> Guillermo Hazebrouck <gahazebrouck at gmail.com> wrote:
>
> > Hi Michael,
> > Thanks for the info. We have not tried that yet (I will try it as soon as
> > we are allowed to go back to our office :-/).
> > I find it strange that it would work for 2.0 since GLX does not seem to
> > implement glBindBuffer, glBufferData or any of the core profile calls. I
> > only see it can handle texture buffers...
>
> Hi,
>
> FYI, the NVIDIA proprietary drivers completely replace almost all of the
> graphics stack, including libGLX IIRC. So anything seen on NVIDIA says
> nothing about any other driver.
>
> To me it seems to have been trend for a decade or more now, that
> transmitting drawing commands is being replaced with transmitting
> images and video, both locally within a machine and across a network.
> Games as a service and so on. I suppose it is not uncommon nowadays that
> transmitting video takes less bandwidth than transmitting the drawing
> commands and the data needed by them.
>
> > The whole OpenGL + X11 world is very hard to digest for newbies like me.
> It
> > grew up like a snowball and seems to have mutated in the meanwhile. The
> > fact that the specification is broken in two parts (call it
> "compatibility"
> > and "core" profiles) is a big pain. And with Wayland I don't see it is
> > getting much better. This comes again as the promise of a new paradise,
> but
> > in fact it is just adding more wires to the already chaotic software
> > protoboard we have.
>
> Actually, Wayland completely removes the ability to go over the network
> at the display protocol level. This follows from the years of changes
> around X11 (and Xorg) where more and more functionality and especially
> performance relies on shared memory and shared file descriptors, which
> also cannot cross a network. Applications no longer submit X11 drawing
> requests, instead they draw locally and submit completed images of
> windows over X11. That needs a lot of bandwidth, but available
> bandwidth is infinite with shared memory - not good for a network.
> Wayland fully embraced that direction of development.
>
> I think the above largely explains why X11 is nowadays generally
> considered to be inefficient going over a network. Another thing about
> X11 is that it is fairly roundtrip-happy. My personal experience is
> that if you stick with ancient apps, X11 forwarding is somewhat usable.
>
> I've been lead to believe the future is VNC-like remoting, but in my
> very casual attempts it has left a lot to wish for. Transmitting video
> instead of data and commands does seem like the only strategy nowadays.
>
> > There are components plugged everywhere and very little documentation
> > explaining the bigger picture, as if the programmers would be so excited
> > about writing "the best software ever" that they never took the time to
> > explain in details what they were actually doing (sorry for this comment,
> > it is a personal frustration against this recurrent behavior of the open
> > source software community).
>
> Yet I find it quite accurate. I'm guilty as well, there is always
> something to improve or a product to ship, and it's not developer
> documentation at the top of a todo.
>
> A bag of random links:
> https://gitlab.freedesktop.org/freedesktop/freedesktop/issues/76
> which might not be quite on topic for you, but just in case...
>
>
> Thanks,
> pq
>
> > El mié., 25 de mar. de 2020 a la(s) 15:05, Michael Saunders (
> > r.michael.saunders at gmail.com) escribió:
> >
> > > Guillermo,
> > >
> > > We have an engineering application that was written using the fixed
> > > function pipeline as well. We have experimented with moving to the
> > > programmable pipeline and noticed this same problem. What we did
> discover,
> > > however, is that OpenGL 2.0 was supported when using GLX. I can't say
> we
> > > tried it on a wide range of X11 platforms but at least between two
> Linux
> > > machines that had native (not nouveau drivers) NVidia drivers it
> worked. We
> > > had to make sure that we were using the older shader language that
> matched
> > > OpenGL 2. I would suggest assembling a simple "hello world" program
> that
> > > renders a gradated triangle where you can easily experiment with OpenGL
> > > versioning and shader language versioning.
> > >
> > > Michael
> > >
> > > On Wed, Mar 25, 2020 at 4:59 AM Guillermo Hazebrouck <
> > > gahazebrouck at gmail.com> wrote:
> > >
> > >> Hello!
> > >> I am having troubles to export an OpenGL-based application through the
> > >> network using X11.
> > >> At the beginning I used only compatibility mode calls (OpenGL 1.2 ->
> > >> lists + glBegin/glVertex/glEnd), and everything worked like a charm.
> > >> However, because a restriction on drivers and OS, I had to move the
> whole
> > >> application to Core Profile (version 3.3 to 4.5). The performance
> remained
> > >> good, but I was no longer able of exporting the application through
> X11!
> > >> I started searching for information and, to my astonishment, it seems
> > >> that the GLX library that is in charge of doing this (forwarding the
> OpenGL
> > >> calls through the network) is now becoming obsolete as it is only
> > >> compatible with legacy (compatibility mode) calls.
> > >> Why is GLX only compatible with OpenGL lists and not able of
> forwarding
> > >> the vertex buffers? Is there any development ongoing in that
> direction? Or
> > >> is there any known solution to this?
> > >> Thanks,
> > >> Guillermo
> > >>
> > >> _______________________________________________
> > >> mesa-users mailing list
> > >> mesa-users at lists.freedesktop.org
> > >> https://lists.freedesktop.org/mailman/listinfo/mesa-users
> > >>
> > >
>
>
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