Netgames are unstable (consistency failures)

Networked multiplayer is currently very unstable and prone to desynchronization. Conjectured reasons are below:

• Thinker code is inconsistent between CPU architectures. (Confirmed for Linux64 and OSX 64)
• Player thinker code is reliant on non-scene state or other potentially unchecked behavior.
• Some consistency degrades due to type conversion from float to fixed and vice versa in player thinker.
• Synch code is broken. It needs to be changed.

Since SRB2 merely multiplexes player inputs to all nodes and hashes some position and item information in each player as Consistancy, any non-marginal difference in player position can cause a desynch.

These problems also affect demo playback, although less significantly. Demos recorded on one architecture may not play back correctly on others. (Not confirmed)

Maintainer notice: please reference other related issues here if they are posted.

Original description by @choalover:

The netcode is something that should be fixed. The synch code is messed up. Rewriting the netcode can make it really stable if done correctly. Make sure you fix it in a new branch called fix-netcode. It annoys alots of players who played SRB2 2.1.X.

Updated description to contain the knowledge we have on the subject. This issue will serve as a blanket issue referencing any more specific issues related to the topic.

Reassigned to @Furyhunter

Do not reassign issues, please.

Assignee removed

...um, there is nothing to be merged yet, why would we make a merge request?

Also, is that just bad english, or are you trying to state that our new netcode will be one like your own mod's, which we have almost no knowledge of to begin with? Not that we'd be interested in doing that anyway most likely.

I have been working on a new networking model, but it won't be ready for some time yet. Please be patient.

In the meantime, the development team has been doing what they can throughout most of 2.1's development, and continues to do so. It's very difficult to fix consistency issues like this and we're doing the best we can. Sorry it isn't perfect.

Status changed to closed

Status changed to reopened

Status changed to closed

With LJSonic's removal of one line regarding overzealous freeing of net commands for servers, the primary bug behind this issue is no more and we are back to 2.0 standards on the whole. There are a few lingering issues which appear to be level specific, but I'm pleased to say that as of the current state of Next, this can be closed.

(I'll note the 64-bit architecture thing is still a problem, but that probably deserves a seperate issue.)

I'm crying.