knogle/libsamp

Libre-SAMP is an experimental open-source reimplementation of a single file: the samp.dll that ships with SA-MP 0.3.7-R5. SA-MP (San Andreas Multiplayer) is a long-running multiplayer mod for the game Grand Theft Auto: San Andreas, and samp.dll is the core client library that handles networking, UI, vehicle sync, player rendering, and other multiplayer features. The goal here is to rebuild that file from scratch using reverse engineering, observed behavior traces, and public server-side references, so that it works as a drop-in replacement without depending on the original proprietary binary. The project is not a finished product. At the current development milestone, the replacement DLL can connect to local test servers, enter the gameplay state, handle basic chat and dialog flows, spawn a local player, create vehicles, display core HUD elements, and render a portion of the TextDraw system (the mechanism servers use to draw text and sprites on screen). Remote player synchronization, full RPC coverage, custom object loading, and several other subsystems are still in active development. Alongside the DLL itself, the repository includes an ASI probe, which is a separate plugin that loads into the game and collects instrumentation traces. Those traces feed the reverse engineering process, providing evidence about how the original DLL behaves so the reimplementation can match it. The code uses an evidence-tagging system in its documentation to mark each implementation detail as observed behavior, a static reference, an inference, or something still needing verification. Building from source requires CMake, Ninja, and the MinGW-w64 cross-compiler. The build runs on Linux and produces a Windows 32-bit DLL and ASI file. A continuous integration workflow on GitHub produces the same outputs and generates checksums. The vendored networking library used is a fork of RakNet, the protocol underlying SA-MP. The project is scoped to compatibility research, local testing, and software preservation. Using it on public servers to cheat or evade bans is outside its intended purpose. It is released under the MIT license.