Quote from AlexMax
If anybody can demonstrate latency or jitter in 2.1 that does not occur when you play on the 2.0 server (please test the two relatively close together), please update this ticket.

<Water`> AlexMax it doesnt appear to happen frequently in duels
<Water`> for some reason, CTF is a lot more painful,
when i was playing duels on 2.1, it was okay for the most part
<Water`> for the duel server, i couldn't tell the difference between random
 packet loss and there being a bug, but in CTF it's a lot more ridiculous

Quote from unknownna

I've been away for a while so I didn't get to test 2.1 properly on real servers until today. I can most definitely confirm that there's a lot more jitter present in 2.1 compared to 2.0.

Quote from unknownna

I also noticed that other clients seem to skip a lot more in 2.1 compared to 2.0.

zandronum -iwad doom2.wad -playdemo ticbuffer_jitter.cld

Quote from unknownna

On a side note, I noticed that it's very easy to desync the weapons when using the proxy settings posted in my former note. This doesn't happen when the tic buffer is disabled.

Quote from unknownna
Disabling the tic buffer seems to completely fix the weapon sync issues (of course not those that we didn't fix yet).

Quote from unknownna
I'd personally rather have rock-solid movement prediction and weapon synchronization instead of having slightly smoother opponents, but that's just my opinion.

Quote from "Torr Samaho"

Some people were constantly complaining that opponents with a bad connection are constantly teleporting instead of moving and thus very difficult to hit.

Quote from Torr Samaho
Can you check how the weapon sync and the jitter is in this binary? It doesn't sort the movement commands, but still has the tic buffer.

Quote from Torr Samaho
I don't like having to make a compromise like this either, but some people were constantly complaining that opponents with a bad connection are constantly teleporting instead of moving and thus very difficult to hit.

Quote from Zalewa
When I play on that private server I have a constant ping of 25 with nearly perfectly reliable connection and I can't hear the end of how much I'm warping...

Quote from unknownna
I can understand the complaints as I've been observing this behavior many times as well. But I still observe this behavior in 2.1, which is probably what Zalewa's linked YouTube video showcases.

Quote from unknownna
On the other hand, since I haven't personally noticed any major weapon sync problems when playing on real servers in 2.1 so far, I'd say that we should keep the tic buffer for now.

Quote from Torr Samaho
From what I understood, this effect is supposedly worse in 2.1 than it was in 2.0. Hopefully, the fix for the jitter of the local player also restores the behavior of 2.0 regarding Zalewa's report.

zandronum -iwad doom2.wad -playdemo ticbuffer_jitter_2.0.cld

zandronum -iwad doom2.wad -playdemo ticbuffer_jitter_2.1.1.cld

Quote from Torr Samaho
Does this effect only happen if the observed player regularly changes its direction (like in your video) or also while the player moves in the same direction for a longer period of time?

Quote from unknownna
It also happens when the player moves in the same direction for a longer period of time.

Quote from unknownna
It's noticeably worse in 2.1.1 compared to 2.0 though, which makes it considerably more difficult to hit the unstable client properly, particularly in close combat. IMHO, it kind of defeats the purpose of having a tic buffer when unstable clients skip around.

Quote from unknownna

But then you simply need to add another server variable that decides whether or not clients should be allowed to disable the tic buffer, right?

Quote from AlexMax
By the way, if you need an easy way to test for weapon desync, BFGSHOOT in Duel40 is a really easy way to make said desyncs appear.

Quote from AlexMax
As a server administrator, I would rather a compromise be struck than potentially having to put up alternative tic buffer/no tic buffer servers.

Quote from Torr Samaho
Yes, that would work, but makes things quite complicated. Are cases where one could convince the server admin that players should be able to opt out of the tic buffer but "sv_useticbuffer 0" is not an option likely to occur?

Quote from Torr Samaho
So weapon sync problems still happen in 2.1 over the course of normal play on that map?

Quote from unknownna
Why would we even need sv_useticbuffer if clients would be allowed to disable the tic buffer at will?

Quote from Torr Samaho
IIRC there were CTF players with a very unstable connection who were very difficult to hit and thus had an unfair advantage when carrying the flag. Those players would surely opt-out of the tic buffer and we get the problem of unhittable players again.

Quote from Torr Samaho
That's also why 1.3 and 2.0 didn't have an option to turn it off.

Quote from unknownna
That's why I'd like to be able to toggle it at will. If I'd play with stable clients I'd turn it off, but if I'd see someone who skipped around a lot and also happened to be my opponent, I'd turn it on.

Quote from Ivan
Is there no way to fix both the client problems to a minimum and the weapon desyncs? They are both equally annoying and frustrating.

Quote from Torr Samaho
I think you misunderstood what the client could decide. [...]

Quote from Torr Samaho
Can you check if this has any effect on the weapon sync problems related to the tic buffer? Chances are not very high, but it won't hurt to give it a try.

Quote from Torr Samaho
I remembered one thing that could cause the backwards jumps, but it should affect 2.0 and 2.1.1 in the same manner: The server sends player position updates to the clients using an unreliable buffer. One of the effects is that if the updates arrive in wrong order at the client, the client will show the player at the position contained in the last update it received, not based on the gametic associated to the position (since the server simply didn't send this information).

Quote from unknownna

It still desyncs very quickly when ping spikes occur, as expected, but under stable conditions (using an emulated ping of 251) it seems to work nearly as good as 2.1. I managed to make it desync 6 times so far, but it seemed to correct itself 3 times. It's still not as good as 2.1 though.

Quote from unknownna
Could you tell us what you did in order to improve the sync?

Quote from unknownna

BTW, does this fix also include this?

Quote from unknownna

Ok, you win, but I'd appreciate it if you at least kept sv_useticbuffer. It'd also make it a lot easier to track potential weapon desyncs unrelated to the tic buffer. Speaking of which, it seems that the sv_useticbuffer value is archived.

Quote from Zalewa

We made another video showcasing the problem that still persists in version 2.1.1:

Quote from Torr Samaho
So this version is worse regarding weapon sync than 2.1 (but better than 2.0), but less jittery than 2.1? Is it better than what we plan to release as 2.1.1?

Quote from unknownna
I noticed that it desyncs very badly after "changemap" map changes in DM. In particular, it breaks badly when using the PK3s found in this ticket. This does not happen in 2.1 or when sv_useticbuffer is set to 0.

Quote from unknownna
Regarding the weapon desync, for some reason the weapons fire twice as fast on the server-end after "changemap" map changes on certain maps. This is really bad.

Quote from Torr Samaho
That sounds pretty bad. Is it any different in 2.0?

Quote from Torr Samaho
Regarding the lag icon: Is this any better?

Quote from unknownna
And unstable clients seem to be just as smooth as 2.0, or perhaps even smoother at times.

Quote from unknownna
I didn't even manage to make it desync even once so far, with or without ping spikes.

Quote from unknownna

Yeah, this is incredible! The weapon sync is now better than 2.1 even. And unstable clients seem to be just as smooth as 2.0, or perhaps even smoother at times. Great job! Weapons also don't desync with ping spikes anymore, which is awesome! This is like having the best of both worlds here.

Quote from unknownna

One thing I noticed is that clients will display the lag icon above their sprites if sv_useticbuffer is set to 0 and eventually time out from the server.

Quote from Torr Samaho
There was a bug in the "sv_useticbuffer 0" case, this should fix it. Possibly this also fixes the "twice as fast" problem.

 docs/zandronum-history.txt | 6 +
 src/sv_main.cpp | 171 +++++++++++++++++++++++++++----------------
 src/sv_main.h | 16 +++-
 3 files changed, 129 insertions(+), 64 deletions(-)