Any reason why prboom would cause savegame desync?

[RamboBones]

In the course of building my doom2 demos I've now run across an interesting problem. I use prbooms in built savegame feature in order to save the state of a demo so that it doesn't have to be recalculated from the start each time, however in my current demo if I set a save point on seemingly any tic after tic 7035 then a desync is quick to follow.

I'm guessing that prboom wasn't designed to allow seamless saving and loading during demo playback however it seems curious that it only happens if I do it after this one exact tic. Either prboom isn't saving everything that is needed to prevent a desync or it's saving in an incorrect compatibility mode or something. Does anyone have any ideas? Because if I can't fix this I won't be able to continue my run very far :(

[Searcher]

I used to get this problem a lot when I was using 2.3, and for example, it seemed to be a constant problem on Gusta's demos even tho' I really doubt he used saved games. It still said there was a save game error and it dropped the demo. He was using 2.6 I think at the time.

It might possibly be a version issue. But I am just guessing here.

[entryway]

You should understand why it occurs.
I don't think that it very difficultly.

[Grazza]

Searcher said:

I used to get this problem a lot when I was using 2.3, and for example, it seemed to be a constant problem on Gusta's demos even tho' I really doubt he used saved games. It still said there was a save game error and it dropped the demo. He was using 2.6 I think at the time.

Regarding Gusta's demos, I'm sure the problem there was that he was using -longtics (by accident, and in version 2.2.6), and that version 2.2.3 therefore wasn't reading the data correctly, as the -longtics feature hadn't been added by then.

I'm not sure of the exact period during which Gusta was inadvertently using -longtics, but it certainly affects some of the his Scythe2 and 2sectors demos. prboom-plus will play these demos correctly.