Constant desync

[KilledJoy]

Anyone else getting constant desync from games, ive tried 4 different lobbies today and all crash either right away upon joining or shortly after someone fired a weapon (they claim)

Ive had the game less then a day and ive already had more issues then games.

[[DEV] BeeMan]

It's possible some of your files are corrupt. To fix that, right click on Forts -> Properties -> Local files -> Verify integrity of game files. It also requires working sound but I'm guessing that's not an issue.

If there are player mods enabled it's use at your own risk, unfortunately. I'm trying to fix problems that come up, but mod authors are often trying strange things that are untested.

[paboss]

Constant desync here too. Been like this from the first minute I played multiplayer, fresh install, no mods.

Tried every solution mentioned in any thread I have found. Reinstall, verify files, "fix audio", turn off dedicated access to sound card, plugged in headset.

Unplayable in multiplayer :(

[Suros:/#]

I had originally thought it was due to my use of Proton. Disabled esync and forced single core to attempt to fix it. Might be seeing less desyncs, but then again that might just be a placebo. There are so many reports of this that I'm thinking that it's more likely just something broken.

[Kagoule]

Same issue here, we both did a verification af game files integrity (no problem), so game is unplayable.

[Nukeyou]

same here

[[DEV] BeeMan]

There is a bug causing a desync when network packets are dropped, so it tends to happen more on flaky connections. I'm planning a patch this weeks. Sorry for the trouble.

[Suros:/#]

Just a heads up. I've mostly been playing with my brother on wired LAN, and desyncs are still common. I'll be sure to let you know what effect your patch has. Thanks for continuing work on this excellent game!

[[DEV] BeeMan]

No worries! For some reason it appears to be more common when both players are on the same LAN.

[[DEV] BeeMan]

I've discovered it's not dropped packets causing the problem on LANs, but a clock synchronisation issue causing clients to run ahead of the host and failing to validate their checksums. I'm looking into a workaround.

[Suros:/#]

You've really got my hopes up now! We've been putting off playing against real players as having around 5-10 desyncs per match is pretty crippling. Also thanks for the updates as I find it quite interesting to know why things happen.

[[DEV] BeeMan]

All good, happy to help.

Got a few things you can try. On the client PC right click on Forts in Steam, then properties, local files, and browse local files. Navigate to data/db then open constants.lua in Notepad or similar. Search for SyncClock and try the following, one at a time (i.e. revert the failed change).

1) Set Enabled to false (no synchronisation)
2) Set PingMin to 0.04 (should avoid the client running ahead)
3) Set PingMin and PingMax to 0.06 or higher (same, but with less scope for error)

If these don't help you can install and run software called Network Emulation Toolkit[blog.mrpol.nl]. I use this to emulate less than ideal networks over my LAN. If you create a link with say 20-50ms of latency in both directions it should avoid the problem. This can be run on the host and then any number of clients on the LAN will be affected. Don't forget to turn it off afterwards.

Let me know how you go.

[Suros:/#]

I've tested the constants with the host acting as observer until I can get people together for proper testing. So far I've had desyncs with each of the settings tested, however disabling the clock sync may have reduced it a bit. I'll post again with results after I can get people together for more complete testing. Can't properly science it without running it the usual way.

Won't be able to test NEWT until later.

On a side note, many larger mods (especially Tanya's Mod) are outright unplayable with many desyncs happening only 5 seconds away from the last rejoin. As mods are rarely perfect and usually outside official control, this just goes to the "nice to have" pile.

Anyway, this is all the info I've got so far. Feel free to use me for any testing.

[[DEV] BeeMan]

OK, thanks for the feedback.

I had another thought. If a client or the host has VSync turned off, or has a very high refresh rate monitor, this will increase the chances of this happening. If this is the case turn VSync on, or reduce the refresh rate in options -> video or within Windows or your video card's control panel.

There are quite a few desync fixes in the pipeline, and I'm looking into another one involving mods.

[Suros:/#]

Oh, that makes sense. I've got it buzzing along at 240Hz. Would setting it to 60Hz in the game's settings suffice?

[[DEV] BeeMan]

Yes, 60Hz will be good. This will all be sorted properly in the next update or two, so you'll be able to return to the previous refresh rate then.