[Mesa-dev] [Bug 59187] [Steam] Implement GLSL 1.30 on Ironlake Mobile/HM 55 (Gen5)

bugzilla-daemon at freedesktop.org bugzilla-daemon at freedesktop.org
Wed Feb 20 08:57:46 PST 2013


--- Comment #5 from Paul Berry <stereotype441 at gmail.com> ---
(In reply to comment #4)
> (In reply to comment #3)
> > In #60481 Ian Romanick said Source-Games would depend on GL3..
> > I demonstrated that the Source-Games don't need full GL3, but just depend on
> > GLSL 1.30 [0]. I run CS:S using Mesa-9.0's softpipe driver (OpenGL 2.1 &
> > GLSL 1.30). So there is probably just some GLSL 1.30 functionallity missing,
> > which could be implemented as a software fallback or using the graphics
> > hardware (if supported).
> > 
> > Where would we have to implement those missing GLSL 1.30 functions?
> > 
> > [0]
> > https://github.com/ValveSoftware/Source-1-Games/issues/19#issuecomment-
> > 13801640
> I can't speak to whether Source games require GL 3.0 or not, but here's a
> rough list of what would need to be added to the i965 driver in order to
> support GLSL 1.30 on Ironlake (this is based on section 1.2.1 "Summary of
> Functionality differences from version 1.2" of the GLSL 1.30 spec):
> - Texture size queries*
> - Texture arrays*
> - Texture offsetting*
> - Explicit LOD and derivative controls*
> - "noperspective" and "flat" interpolation qualifiers
> - gl_VertexID 
> *Some of these may already work on IronLake--I'm not terribly familiar with
> the texturing code.

Argh, sorry.  I hit submit before I was finished.  One more item:

- gl_ClipDistance

Of all of these items, the trickiest one is gl_ClipDistance, since it requires
modifying the Gen4/5-specific "clip" program (brw_clip.c) to perform clipping
in a manner more like what happens in Gen6+ (using clip distances provided by
the vertex shader rather than performing dot products in the clip program). 
This is not a project for the faint of heart--the brw_clip.c code isn't
terribly well tested, and has a lot of tricky corner cases in it.

Once those things are done, we would of course want to run the driver through a
pretty thorough round of piglit testing to make sure we hadn't missed any small

You are receiving this mail because:
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freedesktop.org/archives/mesa-dev/attachments/20130220/01df9d28/attachment.html>

More information about the mesa-dev mailing list