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Reverse Engineering Star Wars: Yoda Stories (2014)

47 points by mmastrac 4y ago

United857 4y ago
Those four letter chunk IDs seem suspiciously like IFF (https://en.wikipedia.org/wiki/Interchange_File_Format https://en.wikipedia.org/wiki/Interchange_File_Format) in which case there's a bunch of generic parsing/extraction code out there which will avoid a lot of reinventing the wheel here.
- cleim 4y ago
  It looks very similar, but it think that’s mainly due to the TLV pattern they both use https://en.m.wikipedia.org/wiki/Type%E2%80%93length%E2%80%93value https://en.m.wikipedia.org/wiki/Type%E2%80%93length%E2%80%93... For some tags the file format deviates from the pattern. E.g VERS does not have a length field.
samspenc 4y ago
I remember doing similar things over 20 years ago with games that had poor customization. Open up the binaries, search for strings, and replace strings with custom text (e.g. character names etc). I learned quickly that I had to keep the string replacement the same length in order to fit with the byte boundaries otherwise the game would crash. But this author has taken reverse engineering to a whole new level, not just finding where text resides, but being able to parse out entire images (maps etc) by finding patterns in the binary representations. Truly Jedi Master level.
orionblastar 4y ago
I remember someone did this and found a Corvette in the sprites that was never used. Mark Hamill in Corvette Summer. A joke.
- King-Aaron 4y ago
  https://yodastories.tumblr.com/eastereggs https://yodastories.tumblr.com/eastereggs
paulryanrogers 4y ago
For another SW game being reverse engineered see TheForceEngine.GitHub.io The project is reversing the Jedi Engine from "Dark Forces" and "Outlaws". The fan doing it is clearly talented and a former game dev.
graderjs 4y ago
This was incredible
dirtyid 4y ago
Fond memories of Yoda Stories and Indy Desktop Adventures, had no idea they reviewed so poorly.
cleim 4y ago
Really great article. For anyone interested, I built a somewhat working reimplementation of the whole game at https://www.webfun.io/ https://www.webfun.io/ Reverse engineering the world generation algorithm and internal scripting language were especially challenging.

47 points by mmastrac 4y ago

Those four letter chunk IDs seem suspiciously like IFF (https://en.wikipedia.org/wiki/Interchange_File_Format https://en.wikipedia.org/wiki/Interchange_File_Format) in which case there's a bunch of generic parsing/extraction code out there which will avoid a lot of reinventing the wheel here.

cleim 4y ago
It looks very similar, but it think that’s mainly due to the TLV pattern they both use https://en.m.wikipedia.org/wiki/Type%E2%80%93length%E2%80%93value https://en.m.wikipedia.org/wiki/Type%E2%80%93length%E2%80%93... For some tags the file format deviates from the pattern. E.g VERS does not have a length field.

samspenc 4y ago

I remember doing similar things over 20 years ago with games that had poor customization. Open up the binaries, search for strings, and replace strings with custom text (e.g. character names etc). I learned quickly that I had to keep the string replacement the same length in order to fit with the byte boundaries otherwise the game would crash. But this author has taken reverse engineering to a whole new level, not just finding where text resides, but being able to parse out entire images (maps etc) by finding patterns in the binary representations. Truly Jedi Master level.

orionblastar 4y ago

I remember someone did this and found a Corvette in the sprites that was never used. Mark Hamill in Corvette Summer. A joke.

King-Aaron 4y ago
https://yodastories.tumblr.com/eastereggs https://yodastories.tumblr.com/eastereggs

paulryanrogers 4y ago

For another SW game being reverse engineered see TheForceEngine.GitHub.io The project is reversing the Jedi Engine from "Dark Forces" and "Outlaws". The fan doing it is clearly talented and a former game dev.

graderjs 4y ago

This was incredible

dirtyid 4y ago

Fond memories of Yoda Stories and Indy Desktop Adventures, had no idea they reviewed so poorly.

cleim 4y ago

Really great article. For anyone interested, I built a somewhat working reimplementation of the whole game at https://www.webfun.io/ https://www.webfun.io/ Reverse engineering the world generation algorithm and internal scripting language were especially challenging.