OpenBGI

This project aims to reverse-engineer the Ethornell Buriko General Interpreter (BGI), and create an open source re-implementation of the engine.

We now have a Discord server: https://discord.gg/3zFTJWUNt7

Workflow

Currently, the workflow is to use Ghidra for analysing the engine, then reimplement opcodes and support functions on a per-opcode basis.

The strategy is just to implement an opcode, run the game and see if it crashes. It's a pretty crude technique, but it'll work for now.

Milestones reached:

• Reimplemented enough basic opcodes for Tayutama to run.
• Standalone engine is being worked on.

Architecture

While we're still working on reimplementing opcodes, but it now makes sense to compile a stand-alone program. Uur strategy is still to hook into an existing engine and redirect functions and opcodes to a shared library, and reimplementing this into the standalone version.

Building

While cross-platform compatibility is our goal, the build chain currenly is only configured for Linux.

Before you do anything else, you need to install the various tools and dependencies needed:

apt install build-essential gcc-mingw-w64-i686

Building the ebgube is as simple as running:

make

Finally, run the engine in the directory of the game files:

cd /path/to/the/game
/path/to/openbgi

The engine expect all game resources to have been extracted from the game using the unarc tool in the tools directory. In due time we will support loading directly from unmodified game assets, but for now it helps development to have assets extracted.

Contact

Feel free to join our Discord server: https://discord.gg/3zFTJWUNt7