On Sun, Oct 29, 2000 at 04:11:45AM +1100, Jamie Honan wrote:
> Abbreviated summary of SLUG meeting, 27 Oct 2000.
Thanks, quite helpful/useful.
> I got in a bit late so I missed the Q&A.
I was there from 6pm and still missed it. The joys of organising :-?
> Gareth Hughes on DRI
>
> Gareth is employed by VA to work on better support and performance for
> 3D cards under Linux.
>
> This is being done through a mechanism called DRI (Direct Rendering
> Infrastructure). Gareth only had time for an overview, but
> this is basically an extension to the X protocol and some
> kernel modules.
>From what I understood it works like this:
before DRI:
quake ---> OpenGL ---> GLX ---> X Server ---> Hardware
GLX takes OpenGL requests and packages them into X packets to send
to the server which then renders them. Great if your display is
not local. Latency and reduced bandwidth if you are.
Nowadays though, displays tend to be local. So with DRI it becomes:
quake ---> OpenGL ---> DRI ---> X Server ---> Hardware
\-------------------> Hardware
DRI takes OpenGL requests and shunts them straight out onto hardware
syncronising with other things (like the X Server, other clients)
and making use of the authenication mechanism X provides.
That is a very simplified way of explaining it though. Gareth did
a much better job.
> DRI should be going into XFree86 4.02. Gareth had some comments
I think DRI is in 4.0 baseline - 4.02 was the ATI radeon driver (he
says thus making sure Gareth gets it in >:-).
> on 3D cards in general. For example the close relationship between
> SGI and Nvidia.
I think he recommend the ATI Radeon card if you just want to use
Free Software. For those don't have principles^W^Wmind binary drivers
nVidia was recommended but keep in mind you have to through out things
like DRI as they have their own system.
> Gareth gave some quite impressive demos, Quake III, the teapot,
> sproingies and couple of others. These were very impressive, with
> quite high frame rates on fairly ordinary hardware.
750 frame/second roughly, for the gears demo iirc.
> There was a little discussion about frame rates and quake, and
> how important they were to survival and winning tournaments.
> (Perhaps the issues could be resolved in a demo tournament :)
In essence: what matters in network play is not your *top* framerate
(the peak) but your bottom framerate matters. Example: with 100 missles
headed in your direction if you peak framerate is 130 and each missle
slows down the framerate but 10 then you'll bottom out at 30fps. Still
enough to see where to dodge to.
> Mama's afterwards was good. A little slow in getting the food, but good
> value I thought. Good to chat to old friends and new.
We had varying comments about it. But there were certainly more of us
(or perhaps having a long table only makes it seem so ...). Thoughts
on switching between HoGZ and Mamma's every month?
> Many thanks to Gareth, if you're reading this, and Conrad.
> To the guys who organise the meetings, they really are enjoyable
> and worthwhile.
Thanks for the feedback - positive feedback is always welcome.
Constructive feedback even more so; most of the feedback we
have received was time related - so I've become more vicious
about it. That is why we left UTS at 21:17 - that and the
21:30 dinner booking :-).
Regards,
Anand
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