Total Newbie - Loading Saves from older version GZDoom

kermit · Post by **kermit** » Sat Nov 08, 2008 3:41

OK this may be a silly question

but....

Is it possible to 'alter' Saved games so that the latest GZDoom [v1-1-05] can load them in ??

I have MANY saved positions for all the Doom Standard WADS (Doom/DII/TNT/Plutonia/Hexen/Heretic) from the previous version [v1.1.4] but 'upgrading' to the latest version of GZDoom & trying to load I get 'Different version' message & my saved games are 'greyed out'

Since I'm ~half way through many of these (on the mid skill level) - I don't really want to start again from scratch.

- I'm guessing there's something in the save file that tells GZDoom what version saved it in the first place & if it doesn't match up with current GZDoom version it won't allow it to be loaded.

Surely some clever person can come up with a 'patching utility' that alter the necessary bit/byte/word (or whatever) in a save file to allow it to be loaded in a different version of GZDoom ??

I bet that there isn't that much difference between a v1.1.4 & 1.15 game save

Post by **Rachael** » Sat Nov 08, 2008 5:14

I think it's very very ill-advised. It's possible that the data structures can change between different versions of the game, and when that happens you're going to run into serious issues, most notably, stability, among other things.

The changes in the game can occur behind-the-scenes, which won't affect you at all, but would affect the savegames dramatically. I know for certain that between 1.1.04 and 1.1.05 there were a LOT of changes.

While what you're asking for is possible, it's just simply not a good idea.

kermit · Post by **kermit** » Sat Nov 08, 2008 6:03

SoulPriestess wrote: The changes in the game can occur behind-the-scenes, which won't affect you at all, but would affect the savegames dramatically. I know for certain that between 1.1.04 and 1.1.05 there were a LOT of changes.

While what you're asking for is possible, it's just simply not a good idea.

Oh Dam

& there's me thinking it was just a version number change that was stopping me loading my current position(s)

I guess that I'll have to stick with 1.1.4 until I complete all the games - Then upgrade to the latest when I go through @ a harder level

Many thanks for the background info

WolfyGirl · Post by **WolfyGirl** » Sat Nov 08, 2008 10:21

just make use of the Console command 'Nextmap".

or "Changemap <mapname here>". Example "Changemap map10".
A very easy methode of skipping annoying level and maybe also in case you lost your savegames.

Post by **Graf Zahl** » Sat Nov 08, 2008 18:51

Just a bit of explanation:

Savegames contain a revision number. When trying to load a savegame this is checked against a minimum compatible number. So if you get an incompatibility message there's not much that can be done.

And the changes between 1.1.4 and 1.1.5 were indeed significant enough that an attempt to load the old ones was not an option.

kermit · Post by **kermit** » Sat Nov 08, 2008 19:57

WolfyGirl wrote:just make use of the Console command 'Nextmap".
or "Changemap <mapname here>". Example "Changemap map10".
A very easy methode of skipping annoying level and maybe also in case you lost your savegames.

yes but 'skipping' = 'cheating' in my book

I'd rather work my way through (although I DO use 'GOD' mode occasionally

)

Post by **Enjay** » Sat Nov 08, 2008 19:59

If you are only using skipping to get yourself to a point in the game where your save game would have taken you to anyway, what's the difference?

Post by **Gez** » Sat Nov 08, 2008 21:15

As a compromise of sort, I'd like the possibility to make saves between levels that would be protected from deprecation as they wouldn't contain any map information.

Post by **Enjay** » Sat Nov 08, 2008 23:28

What if inventory handling changes between versions?

As an aside, I'm always surprised when people have precious save games that they want to hang on to. Doom simply doesn't strike me as a game where savegames are likely to be particularly valuable. I guess they are to some people though.

Post by **Rachael** » Mon Nov 10, 2008 15:20

Maybe a good system to have would be a new save format that deals exclusively with changing levels; it might even replace the normal autosave function.

It of course would not work in Hexen or Strife or any game that used any form of hub system where levels have to be saved, and it also probably should not be used for multiplayer games.

What it would be would be something like an AUTO0000.ASG where the .ASG is simply a .cfg file that's autogenerated similar to the following:

Code: Select all

ECHO Wads loaded: doom2.wad thiswad.wad thatwad.wad etc.wad (for the save description)
SKILL 2
MAP (mapname)
TAKE all
GIVE rocketlauncher
GIVE pistol
GIVE fist
GIVE health 25
GIVE armor 54
GIVE ammo 50
GIVE shells 0
GIVE rockets 2
GIVE cells 0

... and so on. It would simply enumerate every item you had without counts first, and then it would enumerate the counted items.

File could even be .gzipped to discourage cheating, for those who are vehemently against it.

Another thing that might work would be just to even do it in .ini format.

Post by **Graf Zahl** » Mon Nov 10, 2008 17:36

Such a system would only work in non-hub games, In addition even savegames at level start contain additonal information that can't be saved like this.

Jive · Post by **Jive** » Thu Nov 13, 2008 19:04

How strange it is !!!
With Doom Legacy, I never had a problem when the engine was updated between minor changes (from 1.30 to 1.34, let say). I had only to edit the savedgame file, to localise at the beginning the number of the version, and to change it, that was it ! I was able to enjoy the new version, using my old saved game.
Sometimes, it wasn't working, because the changes were very important.

Please Graf, can you think about it, and imagine how could be the structure of an efficient savedgame file, being able to handle changes of the engine?
For example, Doom Legacy... Hey Graf, stop yelling !!!!!! I said: Doom Legacy was able to handle changes being made on textures of a wad without hanging. When I was updating wads, it was very useful, particularly when I put texture where it was missing. Gzdoom can't do such a thing. Why?!? Why the need to store within the savedgame file the textures used?
Maybe you're asking to this file to store unnecessary details?
Please, apologies me if I'm writing stupidities, because I don't know about what I'm talking, but only you!

Post by **Graf Zahl** » Thu Nov 13, 2008 19:13

Sorry, no. The changes between 1.1.4 and 1.1.5 regarding savegames were quite extensive. Some internal data structures were heavily altered so an attempt to convert savegames from 1.1.4 to 1.1.5 is not possible.

Jive · Post by **Jive** » Thu Nov 13, 2008 19:40

All is fine!
What you made with this fabulous engine is astonishing enough to let me having lots of fun.

Maybe a solution:
is it possible to write some sort of script, describing the inventory, the amount of life and so on, so that we have only to load a map, execute the script once the map loaded ?
We would have only to replace the correct values for each of the wanted savedgame.

Post by **Graf Zahl** » Thu Nov 13, 2008 20:09

If it was that simple, savegames wouldn't become incompatible.

And small changes can easily be handled by the savegame code.

But between 1.1.4 and 1.1.5 2 entire subsystems that need to be saved got changed completely and some new features were added that also heavily affected the saved data in a way that makes processing old savegames close to impossible.