[sldev] Re: Questions on the particle system

[Dale Glass]

On Sunday 02 December 2007 22:46:03 Dirk Moerenhout wrote:
> Dale,
>
> what version of the source tree did you start against? If it isn't the
> latest windlight branch I suggest you go check out at least VWR-418
> and VWR-983 first.
I was working against 1.18.4 (kinda old, yeah)

> My particle patches for VWR-418 and VWR-983 are in latest windlight
> though you need the info from VWR-3403 too because there was an issue
> during the merge (latest windlight binary is corrected but I haven't
> seen source yet). You can just lift the related files from the
> windlight branch and put it in another one (mind VWR-3403). There's
> one additional particle patch in there (VWR-2164) but apart from that
> files are pretty much identical to 1.18.3.2 (I used a diff against my
> personal 1.18.3.2 branch to find the issue of VWR-3403).
I just tried Windlight. I seems to share the same annoying behavior.

Meaning, that when running into the particle limit, things start to 
sputter. If you see a fountain, it doesn't shoot less water, it shoots the 
full amount for a frame, then nothing for several, and so on.

It also has the same issue with limiting particles. I only see an effect 
that has about 2500 of them. I have a 4096 limit set, and seeing a lot 
less particles than should be in the full effect.

>
> Argent already replied on the particle count stuff. If it needs to be
> tracked you need to count it. As such it's important to limit at spawn
> and not afterwards.
Why?

> My patches have done that by implementing a 
> dynamic throttling mechanism. The primary basis is particle
> viewability. As such a source spawning larger particles may get
> priority over one that is spawning smaller invisible particles near
> you. It may not be agressive enough to everyones liking but it offer a
> huge improvement over the old code.
I guess that I must be weird, but I disagree here. I find a huge smoke 
stack far away spewing lots of huge particles quite uninteresting. On the 
other hand I want to see a nearby candle, or tiny sparks from a magic wand 
I'm holding.

If the particles aren't visible then IMO they effectively don't exist and 
shouldn't be counted towards the limit.



> On the anti-griefing part the new code has some stuff too as the high
> throttling levels will cut in the amount of live particles a single
> source can want simultaneously. A source may for example try to get
> thousands of live particles by spawning a few at a time but giving
> them long lives. The new code will punish such sources by limiting the
> amount of particles they will get.

Not sure if that's going to be very effective as they can always use more 
prims. My limit is simply based on that particle griefing seldom happens 
right on your land, because if it was there you could remove it.

So my approach is to simply add the possibility of killing all sources more 
than X meters away. Eventually I'm going to mute all particle emission 
from avatars who are banned on the parcel you're on (been planning this 
for a while, but got busy)
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