Sonic Adventure 2 Hacking

In the interest of science and stuff, here is the program to restore pointers to .rel files.

For reference, Green Hill's LandTable can be found at B843C in stg31D.rel.

 

IIRC, they are. I did some texture dumps while playing in multplayer just for shits and giggles to see if there was anything missed way back when, and I found those in there. I've been wanting to know if their coding might still be in the game as well. But I dunno, never really checked...

 

This might be more relevant to the SA1 topic, but since Chao have more recently been mentioned here, I will ask here.

I was wondering, which, if any, of the various versions of the Chao Garden Save files have been documented, and if any tools or guides exist for converting the files between the various platforms?

 

As of this moment, the only one that has been documented is SADXPC's. Since you brought it up, I might look into SADXGC (should be mostly, if not entirely the same) and SA2B. The Dreamcast versions I'm not so sure about, especially SA1, being the first version of the Chao system.

They're probably not so different that converting the Chao themselves wouldn't be possible, but converting the entire file probably won't be possible, because each version has different gardens and items.

 

Arymond has been kind enough to provide me with the default.xex and stg31d.rel files from the XBOX 360 version. So far I have learned that the game apparently still uses actual .rel files, which is odd since it's a Nintendo format. I was able to locate the LandTable, it's still SA2B format, so nothing we can do with that yet.
In the xex file (after decrypting it) I was able to find a texture list, an object list, the code for the ring object (but I don't know PPC ASM), and a model in the same format as SA2B's level models, but no LandTables and only one reference to a level texture file.

This made me think:

Our best hope for the PC version is that they give up and just put everything that wasn't already a separate .bin file into the exe.

 

.rel stands for Relocatable ELF, and it's not a Nintendo format.
http://en.wikipedia.org/wiki/Executable_and_Linkable_Format

 

I don't see anything about .rel files on that page. They're not just .elf files renamed. The only place I have ever seen .rel files is on the GameCube, and the SDK includes tools to convert .elf to .rel, dump information about a .rel file, and library code to load .rel files.

 

I wasn't implying that they were ELF files renamed, they're not. They're relocatable ELF files, without the headers. Nintendo didn't invent that, they just picked the easiest thing to do.

 

So are you saying that there are other things which use this file format? If not, then the format (not the idea of relocatable elf files) is Nintendo's.

 

Yes, that's exactly what I'm saying.

The only examples I can give you though are Sega games. PSO Blue Burst used them, which might be a bad example because it was an enhanced port. But Phantasy Star Online 2 has references to .rel files in memory too, and that isn't coming to any Nintendo platforms. Someone with a more extensive library of games might be able to find more examples for you. I would expect it to be more common on consoles though, considering most platforms already have their own formats for this.

Edit: Oh, and Phantasy Star Universe used them too. This one you can easily verify yourself. Just grab one of the decrypted EXE's from a patched version of the game and search for the file table inside. That was never on a Nintendo platform so it's probably the best example.

 

Well that's interesting. How come I've never heard of .rel files outside of GameCube/Wii then? And why am I apparently the first person to reverse engineer them?

Also, the fact that there are references to files with a .rel extension means nothing unless you can prove they are the same format as the ones used on the GameCube.

 

This is a pointless argument. There isn't even consistency between REL files on the Gamecube, other than the fact that they contain data intended to be loaded into memory at an arbitrary location and used by whatever loaded them. I need to go back to PSO (on Gamecube) as another example, because I haven't looked at SA2 in a long time. In that game, there are several .rel files that are just tables full of strings. There's no format to decipher for those, because the main executable retains the string offsets into the file.

REL files are an artifact of the compiler toolchain. Yes, Nintendo may have made the choice to use that file extension, but there is no evidence that suggests it's a file format that Nintendo created. If the same files weren't compressed into .PRS archives on Dreamcast, Sega could have called those .REL files too if they wanted.

 

There is consistency between REL files on the GameCube, they all start with the same "OSModuleHeader" structure defined in the Nintendo GameCube SDK. The only exceptions I have seen thus far are SADX's compressed REL files, which is probably just a compressed version of a regular REL file. Anyway, I'm sorry for assuming it's a Nintendo-made format just because it's in their SDK and games.

For something actually relevant to the topic at hand, I've started looking at event files, and I think they might be a lot more editable than SA1's events, which are hardcoded.

 

The increasingly inaccurately named SADXPCTools now has an 'SA2' folder, which can split some data from SA2's files.

Currently I have an ini file for STG31 (Green Hill), which splits the object list, LandTable, and models for Big the Cat and the Item Balloon.

There is also splitmdl.bat, which splits every character's MDL file and MTN file (except Super Sonic/Shadow) for easier viewing of my half-implemented SA2 model support and half-implemented animation support. Super Sonic/Shadow's MDL files split fine, and are in the bat file, but their MTN files... seem to have a camera motion or something? I have no idea what the deal with that is, so they're currently unsplittable.

In order to use this, copy the entire folder structure of a US SA2 disc/disc image to your hard drive, and copy the contents of the SA2 folder into the folder with 1ST_READ.BIN.

 

Huh, that's interesting. I wish I could give a reason why they don't split properly, but I don't remember seeing anything funky about them when I was looking through them ages ago. But who knows.

 

Don't Super Sonic and Super Shadow use the same model? Would that screw up the other?