Error when parsing UFO 50 data

[jh05013]

parse_file panics while trying to read data.win from the game UFO 50:

use libgm::prelude::GMData;

fn main() {
	let path = "/home/jh/.steam/debian-installation/steamapps/common/UFO 50/data.win";
	let game: GMData = libgm::parse_file(path).unwrap();
    println!("Loaded {}", game.general_info.display_name);
}

Error reformatted for convenience:

thread 'main' (15535) panicked at src/main.rs:5:48:
called `Result::unwrap()` on an `Err`
value: Error { message: "Expected Unknown Always Zero to be 0 but it is actually 3 (0x00000003)",
context: [
    "deserializing element 0/17 of aligned GMBackground pointer list",
    "deserializing chunk 'BGND'",
    "parsing GameMaker data file /home/jh/.steam/debian-installation/steamapps/common/UFO 50/data.win"
] }

In fact, this "unknown always zero" value seems to grow quite a bit:

bg03_UFO_tileset
3
bg06_Golfania_tileset
6
bg07_GravGuns_tileset
14
bg09_FistHell_tileset
32
bg11_Mooncat_tileset
43
bg12_Cowboys_tileset
44
bg25_AntWar_tileset
69
bg26_Soccer_tileset
76
bg28_Ufoparty_tileset
80
bg30_Overbold_tileset
83
bg31_Elfazar_tileset
84
bg35b_Godsblood_tileset
117
bg37_Incremental_tileset
118
bg38_UFO_II_tileset
126
bg45_CyberOwls_tileset
147
bg51_UfoTower_tileset
160
bg51_UfoTowerGames_tileset_1
163

libgm detects the GameMaker version as 2024.13 (PostLTS), WAD 17.

[BioTomateDE]

interesting. as a temporary fix, you can use

libgm::ParsingOptions::new().validate_constants(false).parse_file("path/to/data.win")

this might also show other errors (possibly related to version detection idk).

i can take a look at this AlwaysZero thing later, but I don't really wanna buy the game for 25€ 😭

(also btw, the errors look better when printed out using .chain() instead of Debug)

[jh05013]

Another error with verify_constants(false):

Invalid extension::Kind 11 (0x0000000B)
> while deserializing element 0/250 of extension::function::Function pointer list
> while deserializing element 0/1 of extension::file::File pointer list
> while deserializing element 0/1 of GMExtension pointer list
> while deserializing chunk 'EXTN'
> while parsing GameMaker data file /home/jh/.steam/debian-installation/steamapps/common/UFO 50/data.win

The data loads without further errors when I add a dummy entry What = 11 to Kind. I'll check later if the data is indeed loaded correctly.

[BioTomateDE]

I think they added some more extension kinds, I got the same error for kind 11 for some other data file. it's just gonna get some stub name (unless we figure out what it is lol)

[BioTomateDE]

regarding the background stuff: I have to update background gms2 data to account for this new 2024 stuff: https://github.com/UnderminersTeam/UndertaleModTool/blob/master/UndertaleModLib%2FModels%2FUndertaleBackground.cs#L180

[BioTomateDE]

alright i added support for 2024.14.1 tilesets and for the extensionkind 11. i also stole version detection for 2024.14.11 from utml. the problem is: that detection requires 2024.13 to be detected first. the only way (i know of) to detect that version is to see if the UILR chunk exists. for some reason, this chunk does not exist in ufo50.

i temporarily forced the version detection to happens anyway. it succeeded (detected 2024.14.1), but broke other parts of deserialization. for example, it still has the 512 byte FONT padding, even though it was supposedly removed in 2024.14??

to be honest, i dont really know that much about gamemaker versioning.
i just steal code from undertalemodlib regarding that. i also tried to load the data file in undertalemodtool but it only detected 2024.4. so im gonna have to wait for smarter people (colinator27, etc) to figure out how to handle 2024.14.1 ¯\_(ツ)_/¯

[BioTomateDE]

alright i also changed the UnknownAlwaysZero to the newly discovered exported sprite index. i think we have different versions of ufo50 tho. can u test out if it works now? (main branch, not on cratesio yet)