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diff --git a/content/articles/girlfriend-of-steel-re.md b/content/articles/girlfriend-of-steel-re.md new file mode 100644 index 0000000..35db72b --- /dev/null +++ b/content/articles/girlfriend-of-steel-re.md @@ -0,0 +1,75 @@ ++++ +title = 'Reverse Engineering _Neon Genesis Evangelion: Girlfriend of Steel_' +date = 2026-04-22T20:30:53-05:00 +draft = true ++++ + + + +Last year, I started reverse enginering _Neon Genesis Evangelion: Girlfriend of Steel_ with the intention of writing a replacement engine that runs on modern computers. +I ended up losing interest, but not before cracking a few of the game data formats. I'm going to document them here, that way anyone who takes a similar +interest in restoration or modding can have a head start. + +The source code of the abandoned project is available here: [fantatech-1776908508.tar.gz](/files/girlfriend-of-steel-re/fantatech-1776908508.tar.gz). +It includes [ImHex](https://imhex.werwolv.net/) patterns and rudimentary decoders for some of the formats described below. + +## What game am I talking about? + +I actually looked at two different games. I will share the information I know about the 1997 formats, but the primary focus will be on the 2006 version. +VNDB has a good record of all the available ports and translations here: [https://vndb.org/v556](https://vndb.org/v556). + +**_Neon Genesis Evangelion: Girlfriend of Steel (1997, PC)_**: This is the original release of the game. It's also the most widely available. +I was able to buy a factory sealed copy on eBay. Surprisingly, you can still mount the ISO and run the ~30 year old binaries on Windows 11. It plays mostly +fine with a [Shift-JIS locale emulator](https://github.com/xupefei/Locale-Emulator). +The chunky bitmap graphics and audio, although charming, are considerably lower quality than in the 2006 version. + +**_Neon Genesis Evangelion: Girlfriend of Steel (Special Edition) (2006, PC)_**: Also called _Shin Seiki Evangelion: Koutetsu no Girlfriend Tokubetsu-hen_, is a remake. +It has upgraded sounds and visuals, additional scenarios, and a full-motion video (Cinepak) intro sequence. It's also filled to the brim with DRM that makes it completely +broken on any system that isn't running Windows XP with Direct3D acceleration. +This will only run in VMWare because VirtualBox dropped 3D acceleration support for Windows XP guests. + +I have not been able to find a physical copy of the PC version of Special Edition for sale anywhere. +The PSP version is available, but the image resolutions are smaller than those found in the PC version. + +Luckily, someone in 2020 found a copy and had the foresight to rip the disc and upload it to the The Internet Archive. This is the raw, original disc; DRM and all: +[https://archive.org/details/ssekngpcredump](https://archive.org/details/ssekngpcredump) - [http://redump.org/disc/74520/](http://redump.org/disc/74520/). + +MD5: `536adbefc80a84378b65224fddf122e7` SHA-1: `77a03fb1823cb96189ac50b9afece8930e709c93` + +## Getting around DRM + +Special edition is secured with [SafeDisc](https://en.wikipedia.org/wiki/SafeDisc). It's completely broken on modern Windows, so you'll need to use a virtual machine to run the game. +I had good success with Windows XP in VMWare with 3D acceleration enabled. + +Once the game is running in the VM (lots of fiddling, unfortunately) the executable can be dumped with [Scylla x86](https://x64dbg.com/). +To save you the headache, here's the dump: [mana01_dump.tar.gz](/files/girlfriend-of-steel-re/mana01_dump.tar.gz) + + + +Although it doesn't run, the dump is a correct PE file. +Ghidra is able to create proper data and code cross-references. Here's a function that parses script keywords: + + + + +## Custom file types (1997) + +* **BP2**: Image (1997) +* **BP3**: Image (2006) +* **LB5**: Lump file +* **TXT**: Game script +* **ZDF**: Animation data + +## Prior work + +When reverse engineering the 1997 game executable, I found several strings referencing something called "bmpwaku". +This was the name given to the tiled bitmap rasterizer written by programmer RitsurÅ Hashimoto. + +A small portion of the source code is still available on his website to this day: [bmpwaku.cpp](http://www.ritsuro.com/prog1/bmpwaku.html). +This wasn't particularly useful, but it was cool to find. + +Aside from that, here are the existing tools I looked at: +* [evac010](https://www.vector.co.jp/soft/win95/art/se055672.html): BP2 <-> BMP transcoder, likely written when the game came out in the 1990s. +* [mdukat/EvaGOS\_engine](https://github.com/mdukat/EvaGOS_engine): Includes partial documentation of the game scripting language from the 1997 game. +* [lb5\_decode.c](https://d3suu.neocities.org/EvaGOS_engine/lb5_decode.txt): LB5 unpacker, written by either mdukat or roxfan. +* [Durik256/GOS2-Tools](https://github.com/Durik256/GOS2-Tools): Tools for dealing with files found in Girlfriend of Steel 2. Some overlap. |