[Mesa-users] Using OpenGL 4+ with libOsMesa v11.1

[Brian Paul]

On 02/01/2016 01:16 AM, Anton Zachesov wrote:
> Hello, everyone.
>
> My name is Anton, I'm working on a small application, which runs
> back-end pre-rendering for a webGL player. It uses software rendering
> implementation from libOsMesa and is intended to use only software
> rendering. It currently uses libMesa 10.2.7.
>
> Recently one part of this app has migrated to OpenGL 4.0, which require
> update to a newer version of libMesa. I picked 11.1.1, as it is claimed
> to have implementation of OpenGL 4.

Only for the Intel i965 driver at this time.


> I built libOsMesa library (from v11.1) with the following command:
>
> ./configure --enable-osmesa --disable-driglx-direct --disable-dri
> --with-gallium-drivers=swrast --disable-egl
>
> The output libOsMesa.so library runs fine with the previous version of
> my app.
> However, when I try to link it with the newest version, I get undefined
> references to
> - glUniformSubroutinesuiv
> and
> - glGetSubroutineIndex
> which are used in the migrated part.
>
> My question is:
> Does the latest version of software rendering with libOsMesa supports
> this particular OpenGL functionality?

No.


> If so, how to build it correctly or correctly link with my application
> (it uses scons to build, if it is important. Any hints are appreciated)?
> If not, how to still use off-screen rendering from libOsMesa with
> support of OpenGL 4.0+?

It'll probably be quite a while before OpenGL 4.x is usable with OSMesa. 
  There are three possible software drivers that can be used with the 
OSMesa interface:

1. swrast - the original software driver
2. softpipe - gallium software driver
3. llvmpipe - gallium LLVM-based software driver.

I doubt 1 will ever support GL 3 or 4.
2 and/or 3 will probably support GL 3/4 someday, but we're quite a ways 
away from it.

Nowadays, off-screen rendering can be done with almost any OpenGL driver 
if you use framebuffer objects (or pbuffers).  Plus, you can get GPU 
acceleration, if present.

Do your machines not have GPUs?

-Brian