[Mesa-dev] OpenGL ES only configuration (without "desktop" OpenGL support)

[Siarhei Siamashka]

On Mon, 12 Aug 2013 14:09:39 -0700
Chad Versace <chad.versace at linux.intel.com> wrote:

> On 08/06/2013 09:44 PM, Siarhei Siamashka wrote:
> > On Tue, 6 Aug 2013 15:54:57 -0700
> > Matt Turner <mattst88 at gmail.com> wrote:
> >
> >> On Tue, Aug 6, 2013 at 2:13 PM, Siarhei Siamashka
> >> <siarhei.siamashka at gmail.com> wrote:
> 
> >>> But if upstream Mesa treats this configuration as unsupported, then I
> >>> also don't see it progressing anywhere in Gentoo. So could you please
> >>> re-consider this decision?
> >>
> >> As far as I'm aware, ES without Desktop GL is disallowed only because
> >> it was discovered to be broken
> >> which is because no one working on Mesa appears to test it.
> >
> > I have not done any really serious testing. I'm just playing around [...]
> 
> 
> >> If you can test it (and provide patches when you notice that it's
> >> broken) I don't have a problem with allowing ES-only builds.
> 
> I agree. If you can fix Mesa to support ES-only builds and do *serious*
> testing with Piglit and some real ES applications to prove that it works,
> then I'm not opposed to supporting that configuration.

That's a really good point about Piglit.

Also if you wonder about what can be run with OpenGL ES only (and
without OpenGL), then here is some initial list:

Qt5 works, KWin works, glmark2 works, OGRE works to some extent (simple
demos run, but not full fledged games). WebGL in Firefox also works,
but still has some issues:
    https://bugzilla.mozilla.org/show_bug.cgi?id=788319

But anything, that wants GLU as a dependency, simply does not build.
Some applications desperately want to link with -lGL for no reason.
If you want an example of such problematic package, a good one
is mesa demos - http://cgit.freedesktop.org/mesa/demos
While it is supposed to provide the es2gears test program, it does not
build out of the box:

    checking for GL... no
    checking GL/gl.h usability... no
    checking GL/gl.h presence... no
    checking for GL/gl.h... no
    configure: error: GL not found

And so on. There is definitely some work to do on the applications
front.

PS. I would be grateful if somebody could advise a highly dynamic and
enjoyable OpenGL ES compatible open source 3D game (not Quake3!). Tux
Rider World Challenge seems to be promising (as a GLESv1 testcase),
but needs some porting back to Linux and X11 EGL:
    http://www.barlow-server.com/tuxriderworldchallenge

-- 
Best regards,
Siarhei Siamashka