[Mesa-dev] Question: st/mesa and context-shareable shaders

[Erik Faye-Lund]

On Mon, Sep 28, 2015 at 4:39 PM, Roland Scheidegger <sroland at vmware.com> wrote:
>
> In short, for simplicity, only things were sharable which were really
> required to be shared (pretty much just actual resources - and yes that
> doesn't work too well for GL neither as you can't share sampler/rt
> views, let's face it GL's resource model there from legacy GL is a
> disaster, not that d3d9 was any better).

OpenGL allows sharing the objects that potentially take up a lot of
sharable memory, like shaders, programs, texture images, renderbuffers
and vertex buffer objects. But not those who does not, like
framebuffer objects and sampler objects. This makes a ton of sense to
me, and calling this model "a disaster" seems quite unfair.

> And IIRC multithreaded GL in general never really used to work all that
> well and noone was really using that much.

That's not quite true. I've been writing multithreaded OpenGL
applications professionally for the last 7 years, and I've experienced
very few problems with the proprietary drivers in this respect. OpenGL
multi-threading works fine, and is in rather heavy use out there. You
might not see those applications, but they exist. And they have been
existing for a long time, without notable problems.