ZDoom multiplayer setup, troubleshooting and FAQ

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Re: ZDoom multiplayer setup, troubleshooting and FAQ

Postby Danfun64 » Tue Oct 18, 2016 2:56 pm

Something that I forgot to ask earlier. Does ZDoom have issues if it connects to servers running an exe with a different architexture, for example, a 32-bit windows binary connecting to a 64-bit linux server? I thought I have heard otherwise, but I would like it double checked.
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Re: ZDoom multiplayer setup, troubleshooting and FAQ

Postby Rachael » Tue Oct 18, 2016 3:03 pm

It shouldn't, but that doesn't mean it won't. The biggest issue is how floating point math is calculated cross-platform due to the use of two different compilers. This problem has been addressed multiple times, but it's one of those kinds of things that's hard to keep a 100% eye on.

The only way to know for sure is to try it. Make sure that your Windows client and the Linux server are using the exact same checkout from Git. If necessary you can also try building with MinGW-w64. If there are going to be problems, you should know fairly quickly.

As far as cross-bits themselves though, they should work perfectly, unless you're using two different processor types (i.e. Intel vs ARM vs PPC) - in which case, I don't know exactly what will happen, there, again you'll just have to see.
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Re: ZDoom multiplayer setup, troubleshooting and FAQ

Postby Danfun64 » Tue Oct 18, 2016 5:36 pm

I don't think I can compile 32-bit software on Linux, and I don't think compiling with MinGW-w64 works with Windows builds. Also, I prefer compiling software and putting them in directories to "installing" software in Linux...

I know GZDoom has an official 64-bit windows binary. Do you think using said official 64-bit Windows binary with a 64-bit self-compiled Linux build of the same version and the pk3 from the 64-bit Windows ZIP will do well with each other, or at least, better than some of the alternatives?
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Re: ZDoom multiplayer setup, troubleshooting and FAQ

Postby Rachael » Tue Oct 18, 2016 6:20 pm

I think you missed a very important point in my previous post - you should be fine crossing 32-bit and 64-bit in a network game as long as the processor architecture is the same. The problem you're more likely to have is a GCC-compiled ZDoom vs a MSVC++-compiled one.

Personally, I think it should work just fine. But again, I don't know, I haven't tried it myself. You will just have to give it a shot and see.
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Re: ZDoom multiplayer setup, troubleshooting and FAQ

Postby Danfun64 » Tue Oct 18, 2016 7:11 pm

So according to the ZDoom wiki, when it comes to MinGW-W64 compiling, " The following information is severely outdated and will probably no longer work! Help in updating this section would be appreciated.", not to mention that MSVC++ can't compile to Linux...so basically there's no guaranteed way of making sure the floating point math is handled 100% the same on both platforms.....

Lovely -.-
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Re: ZDoom multiplayer setup, troubleshooting and FAQ

Postby Rachael » Tue Oct 18, 2016 10:24 pm

Do you have access to both a Linux and Windows machine?

Best thing to do is record a demo on one machine (say, Windows) - make it long, at least 4-5 minutes or so. Make sure it's complex enough, too, and that you're bonking into walls and colliding with demons and doing funny aiming with your gun - pretty much anything that will cause floating point sync problems.

Send that demo over to Linux and play it back. If it's rock solid and you're still in sync by the end of it, the chances of net compatibility are extremely high.

EDIT: I just tried it, myself, with the same version on both Windows and Linux - I recorded a demo on Windows, and then played it on Linux, and on Linux it played perfectly. So - like I said - the problem is addressed repeatedly (pre-emptively, mostly) and right now it does not seem to be a problem. You really should be just fine, and I really think you're overthinking it! If it does desync, just save the game, and rejoin from the same save. There should be no issue. Just practice some common sense - i.e. make sure you're both using the same mods, same versions of mods, same version of the game (sans platform) - things of that nature, and you should be just fine.
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Re: ZDoom multiplayer setup, troubleshooting and FAQ

Postby Edward-san » Wed Oct 19, 2016 5:37 am

A really good test would be with actors walking on slopes, because that's where the calculations (in particular in the function FindRefPoint) might depend on the double precision implementation.
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Re: ZDoom multiplayer setup, troubleshooting and FAQ

Postby Danfun64 » Wed Oct 19, 2016 9:35 am

Unfortunately, the multiplayer sessions I planed on having would have begun with vanilla/limit-removing maps with "Doom (Strict)" complevels and free look, crouching, and jumping forcibly disabled. (ZDoom has several valuable coop features most other ports, especially MBF and prior, don't have, like double ammo outside of nightmare, keeping keys after dying, multiplayer cheats, respawning items. Since most of these features are in Odamex, and since Odamex has more vanilla behavior, I'd use that port if it weren't for some nasty coop bugs... the worst one involving monster desyncs, no less!)

When I get the chance, I'll try the demo playback method, but is there a specific map I should try?

Also, are there plans to ensure GCC compiling of (G)ZDoom works on Windows?

Edit:oh, the demo playback method has already been tested?

...OK.
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Re: ZDoom multiplayer setup, troubleshooting and FAQ

Postby Dragon Mech » Mon Sep 18, 2017 3:05 am

hello. i've just installed GZDoom 0.2.1 on a pair of RCA Viking Pro 2 in 1 tablets running Android 6.0.
my question is: is it possible to start a 2 player network using either a wifi direct (ad hoc) connection, or a bluetooth connection?
i don't have a wifi network at home and the tablets can't use cellular data.
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Re: ZDoom multiplayer setup, troubleshooting and FAQ

Postby wildweasel » Mon Sep 18, 2017 9:32 am

Dragon Mech wrote:hello. i've just installed GZDoom 0.2.1 on a pair of RCA Viking Pro 2 in 1 tablets running Android 6.0.
my question is: is it possible to start a 2 player network using either a wifi direct (ad hoc) connection, or a bluetooth connection?
i don't have a wifi network at home and the tablets can't use cellular data.

I have no idea about the Android version (it's not part of the mainline source, and the version number indicates it's someone else's project) - I'd go ask whoever maintains the Android version for help.
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Re: ZDoom multiplayer setup, troubleshooting and FAQ

Postby Dragon Mech » Tue Sep 19, 2017 12:34 am

thanks for information. i'll get right on that :)
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Re: ZDoom multiplayer setup, troubleshooting and FAQ

Postby Wuerfel_21 » Sat Oct 14, 2017 10:42 am

Does anyone know which DMFlags settings result in a good Hexen coop mode?
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