[osg-users] Specifying the GL context version to request

Robert Osfield robert.osfield at gmail.com
Mon Aug 21 10:46:33 PDT 2017

HI Sandro,

On 21 August 2017 at 18:16, Sandro Mani <manisandro at gmail.com> wrote:

> Sure. However I'm curious, how is the logic supposed to work under
> Windows, where support for specifying the GL version was already
> implemented? Wouldn't you hit the same issues on that platform also?

So far it's be a niche feature used by small number of developers on their
specific applications/platform combinations.  Functionality in the OSG
community gets developed on a need basis, so if the functionality isn't
there yet then it's because few people have required it.  There are so many
things one can do in real-time graphics one has to spend ones time on the
most important issues one hits upon with your own applications.

> I see it as a constraint on osgEarth working with Intel drivers and recent
> GL versions and associate drivers.  What we are talking about is working
> around these constraints in the driver to provide to full osgEarth
> functionality across a wider range of hardware.  The first step has been to
> add the GL version functionality to OSG's GLX support.
> Whether we need to push any changes to osgEarth is something I'm not clear
> on, if the above export's now work with OSG master and osgEarth then I
> think we are most of the way to getting what is reasonable to expect.
> Not that I want to be annoying or repetitive, but surely it's not ideal
> that osgEarth::Capabilities::Capabilities performs it's checks with a 1.0
> context, even though you specify OSG_GL_CONTEXT_VERSION=4.0? Or am I
> missing something here?

Having the the OSG to worry about is enough for my little brain, I can't
comment on the specifics of 3rd party software that builds upon it.
osgEarth has evolved alot over the years, the Capabilities functionality is
something I'm not familiar with at all.  All I can say in general is that
one would typically check for functionality supported by the driver once a
graphics context has been created, if one did create a dummy context just
testing functionality then you'd want to make sure it's created with the
same settings as you create the final viewer windows.

If osgEarth doesn't do this then it's something to take up with the
osgEarth team,

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