Generally, decompilation is a fairly advanced skill. If you aren't already familiar with it, it will likely take you months, or even years, to learn the skills necessary to do it (depending on your current proficiency with C/C++ and x86 assembly). If you're still interested, [part 1 of the decompilation vlog](https://www.youtube.com/watch?v=MToTEqoVv3I) covers the overall process and should give you a starting point that you can dive in from.
For documenting the original binaries and generating pseudocode that we decompile with, we primarily use [Ghidra](https://ghidra-sre.org/) (it's free and open source). To help with collaboration, we have a shared Ghidra repository with all of our current work. You are free to check it out and mess around with it locally, however to prevent sabotage, you will need to request permission before you can push your changes back to the server (ask in the Matrix room).
If you have contributions, feel free to create a pull request! Someone will review and merge it (or provide feedback) as soon as possible.
Please keep your pull requests small and understandable; you may be able to shoot ahead and make a lot of progress in a short amount of time, but this is a collaborative project, so you must allow others to catch up and follow along. Large pull requests become significantly more unwieldy to review, and as such make it exponentially more likely for a mistake or error to go undetected. They also make it harder to merge other pull requests because the more files you modify, the more likely it is for a merge conflict to occur. A general guideline is to keep submissions limited to one class at a time. Sometimes two or more classes may be too interlinked for this to be feasible, so this is not a hard rule, however if your PR is starting to modify more than 10 or so files, it's probably getting too big.
This repository currently has only one goal: accuracy to the original executables. We are byte/instruction matching as much as possible, which means the priority is making the original compiler (MSVC 4.20) produce code that matches the original game. As such, modernizations and bug fixes will probably be rejected for the time being.
* [`3rdparty`](/3rdparty): Contains code obtained from third parties, not including Mindscape. Generally, these are libraries that have been placed in the public domain or are freely available on the web. As these are unaltered files, our style guide (see below) does not apply.
* [`ISLE`](/ISLE): Decompilation of `ISLE.EXE`. It depends on some code in `LEGO1`.
* [`LEGO1`](/LEGO1): Decompilation of `LEGO1.DLL`. This folder contains code from Mindscape's custom in-house engine called **Omni** (file pattern: `mx*`), the LEGO Island-specific extensions for Omni and the game's code (file pattern: `lego*`) as well as several utility libraries developed by Mindscape.
* [`tools`](/tools): A set of tools aiding in the decompilation effort.
## Tooling
Please make yourself familiar with the [available tooling and annotations](/tools/README.md).
In general, we're not exhaustively strict about coding style, but there are some preferable guidelines to follow that have been adopted from what we know about the original codebase:
We are currently using [clang-format](https://clang.llvm.org/docs/ClangFormat.html) with a configuration file that aims to replicate the code formatting employed by the original developers. There are [integrations](https://clang.llvm.org/docs/ClangFormat.html#vim-integration) available for most editors and IDEs. The required `clang-format` version is `17.x`.
The following conventions should generally be applied everywhere except for the utility libraries (`LEGO1/realtime`, `LEGO1/tgl`, `LEGO1/viewmanager`) and any 3rd party libraries (`3rdparty`).
- Within the Omni engine (file pattern: `mx*`), instead of C++ primitives (e.g. `int`, `long`, etc.), use types in [`mxtypes.h`](LEGO1/mxtypes.h) instead. This will help us ensure that variables will be the correct size regardless of the underlying compiler/platform/architecture.
For any further questions, feel free to ask in either the [Matrix chatroom](https://matrix.to/#/#isledecomp:matrix.org) or on the [forum](https://forum.mattkc.com/viewforum.php?f=1).
