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Mythos Modding

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I was playing around with the gamefiles recently,


trying to find out a way of reading out:


  • picture files of weapons, interface etc..
  • quest names+descriptions ..
  • 3d model data+effects ..
  • world map data ..
  • localisation/translation files ..
  • maybe als hoping to find skill descriptions, dependencies, modifiers, etc somewhere..


you can download and install the client from here:





What I found out so far:


  • Mythos still uses the same game data file formats as it did in old client,
  • and Mythos still uses the same game data file formats as Hellgate London does.
  • you can extract the *.dat files
  • you can't read the 'cooked' files by default (eg. 'cooked' .xls or .xml files)



in the root folder where you installed Mythos to, there is a folder named data_mythos


inside it, there are all the relevant *.dat and *.idx files ..



I used a small program called Unhell -


as found on XeNTaX - game research forum,


which was developed for hellgate - but works for mythos too:

(tool is command-line based)




now, this will extract and unpack all the *.dat content,


however you can't open most of the 'cooked' files, that you will get as a result..


you can, however, listen to most of the sound files for example..



Now, I'm looking for a way to view the content of the cooked excel and xml files for example.. ?



also, maybe this could help to.. started an inquiry over at hellgateaus.com as well:




They are modding Hellgate for SP, with quite some success ...

(remember that hellgate and mythos both use very similar technology/gamefile-formats etc)





check this out:

Reanimator - A Hellgate Modding Tool




greetings bob

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got a hint from one of the hellgateaus modders :



For the .txt.cooked files, that involves looking through the executable, after analysing it with IDA. And is a very long, involved process. I've gone through the single player game, the multiplayer game, and the japanese beta, and unless you've got a lot of time on your hands, are patient(don't mind repetitive work), and can read assembly, then you'll struggle.


I have thought about going through mythos, but I've been having a break from it, and can't tell you when I'd go through it.


Here's a brief rundown of what I'd do.

After analysing with IDA, I would then find the file definitions. Generally, searching for the file name helps, because it will show the definition name, which can have _DATA, _DEFINITION at the end, or be completely different to the filename.

Once I've got the definition, I would go through it, and typing in a text file, note the name of the columns, their type(int32, float, etc), and their offset(where they are relative to each other. not many of them are in order as they appear in the file though.).

Then, double check I've got every column name, and go through placing them in order, from lowest offset(first column) to greatest(last column).

After that, open 010 editor, and with the column names, create a template, and check again that I have everything, and that I've accounted for any unused columns(these may be undefined in the executable, or not in there at all).

And then, convert the template into a .cs file so reanimator can read it. And also fix any mistakes I've made, columns I've missed, or placed wrong.

Repeat for all files.


I didn't work on either the xls, or xml cooked files, so I can't help you there.


So, anyone in here who worked with assembly code / assembler / disassembler before ? :)


greetings Bob

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got another PM from one of the Reanimator Devs,


this time regarding the .xml cooked files..


Hey there,


In Reanimator, we have reverse engineered most of the game files.


The .txt.cooked files are relational datasets that require individual class definitions which have been constructed by reading the game ASM.


Other formats like the .xml.cooked files require special definitions too.


A lot of the definitions we have may still work on the Mythos files but its likely they have been branched since FSS and wouldn't share the changes.

You could easily append the new class definitions to Reanimator to load the Mythos files but youd have to still read the ASM to get them.

Check out the source code on the google code page http://code.google.com/p/reanimator/ if your interested. Hope this helps



nobody in here with any clue, willing to help get this project started ? :)

Edited by Rotluchs

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