[sldev] Avatar Rending Speed (was: How server decide what to send?)

[Callum Lerwick]

On Fri, 2008-01-18 at 07:46 -0800, Dzonatas wrote:
> Callum Lerwick wrote:
> > You're barking up the wrong tree. If you want higher framerates, figure
> > out why avatar rendering is so goddamn slow. It dwarfs all other
> > rendering by far.
> >   

> There was some patches posted to speed up avatar rendering, but that 
> effort has been ..uhm.. derailed.

Where?

> Now that Windlight is coming out with its low quality avi tradeoff for 
> framerates, those patches don't seem to matter anymore.

Wrong. On even my fastest systems, (Radeon r300's) a mere three avatars
on screen drops the framerate like a rock. Impostors may help in really,
really busy areas, but they are not the answer. Impostors also eat up
valuable texture space.

Something seems very very wrong in that hanging out with a mere two or
three friends in a mostly empty sandbox kills the framerate so much.

I've stood in busy areas and toggled Avatar Vertex programs on and off.
At best, there was maybe a 0.1 change in framerate. Vertex programs do
not appear to be the answer either.

All profiling I've done consistently shows that the vast majority of run
time is actually spent inside the OpenGL drivers (and OpenJPEG). This
suggests to me that the problem is not a cycle-shaving issue in
slviewer, but a fundamental issue in the avatar rendering algorithm, an
issue in the way OpenGL is being used.

Game engines like Doom3 and Source appear to manage to render larger
numbers of much more detailed skeletal animated entities, with much
higher performance on the very same hardware. As they're not currently
open source, I haven't a clue how they're doing it.

And of course SL seems to be locking up my Wintendo upon loading the
HTML login screen at the moment, so I can't try and get some real
numbers at the moment. Sigh.
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