X4Native — Native C++ Extension Framework for X4: Foundations [Beta]

[eg3r]

X4Native — Native C++ Extension Framework for X4: Foundations [Beta]

Hey everyone,

I've been working on something for X4 modders who've hit the limits of what Lua and MD XML can do on their own: X4Native — an open-source framework that lets you write X4 mods in C++, with direct access to the game's internals.

Lua is great for UI and glue code, and Mission Director handles game logic well — but some things just aren't possible (or practical) without native code. Think: intercepting game function calls, accessing the full range of 2,000+ exported game functions with proper typing, building performance-critical logic, or bridging game systems in ways Lua alone can't reach. X4Native fills that gap.

This is a first public release. The core framework is functional and tested, but the API may still evolve. Feedback and bug reports are very welcome.

Features

• Full access to X4's exported API (GetPlayerID, GetComponentName, IsPlayerValid, etc.)
• Function hooking — before/after hooks on any game function (inspect args, modify behavior, skip calls)
• Event system — lifecycle events, custom C++ events, and Lua-to-C++ bridges without writing any Lua
• Hot-reloadable core — /reloadui picks up new DLL builds without restarting the game
• Clean C++ SDK — modern C++23, single #include <x4native.h>, everything in the x4n:: namespace
• Auto-discovery — drop extension folders into extensions/, the framework finds and loads them

Quick Example

Code: Select all

#include <x4native.h>

X4N_EXTENSION {
    x4n::log::info("Hello X4!");

    x4n::on("on_game_loaded", [] {
        auto* game = x4n::game();
        UniverseID player = game->GetPlayerID();
        x4n::log::info("Player ID: {}", player);
    });
}

Installation (Players - Currently no value, unless extensions exist)

1. Download x4native-vXXX.zip from the Releases page
2. Extract into your X4 extensions/ folder so you have extensions/x4native/
3. Disable Protected UI mode in game settings (Settings → Extensions → uncheck Protected Mode)
4. Launch the game — check extensions/x4native/x4native.log to verify it loaded

Building Extensions (Developers)

1. Grab the SDK zip from the same Releases page
2. Point your CMake project at the sdk/ headers
3. Build a DLL, drop it in an extension folder with a content.xml and x4native.json, done

Full developer guide with API docs, hook examples, Lua bridging, and MD event forwarding:
Extension Developer Guide

Links

• Download: x4native-vXXX.zip
• Source & Docs: github
• Extension Guide: EXTENSION_GUIDE.md
• Contributions: CONTRIBUTING.md

Requirements: X4: Foundations v9+ (current beta), Windows x64, Protected UI mode OFF.

This is a beta — if you run into issues or have suggestions, open an issue on GitHub or reply here. I'm looking forward to your input.

Happy modding!

[ChemODun]

Sounds interesting, but your LLM not fully understand a content.xml structure…

[eg3r]

Thank you for your feedback! It will get its tokens reduced for a week as punishment for the oversight.

[beko]

> Windows x64

was interested until that. None around, can't test, don't see why this is a requirement

[IlikeThisgame]

sad that this has to come 8 years after release from a user, but ill sure test it, when i have time, i think about writing x4 mods now for a long time.

[eg3r]

> Windows x64

was interested until that. None around, can't test, don't see why this is a requirement

Hi there! I knew this question would come sooner or later

Let me first say it was a deliberate decision for the beta (and probably fervor once you understood the underlying problems).

This is a hooking library to give extension developers benefits compared to the current extension system of X4:

• Access functionality that is not exposed or too internalized to be exposed to current extensions
• Give a possibility to continue writing in their favorite language (which is obviously C++) and not dive into lua or md (too deep)
• Circumvent the performance overhead of lua or md

With that a certain need arises that is a very "special" field in computer science: Reverse Engineering
And so comes the question of builds into the spotlight: Address-Spaces
Which are very different for a windows and for example a linux build binary.

Lets assume Egosoft releases per year 2 major versions and per each about 4 hotfix versions, that means whoever reverse engineers certain "custom" things in this project would need to do it for all of the supported operating systems (would be 2x lin/win). This is a hobby project and the time needed even when using latest tech (like LLMs) is still not zero. Beside I would need to run the game and the whole testing/dev/re setup on my linux machine too, the effort is huge.

The good news are:

• Current X4Native architecture would pretty much support 2 OS builds (just need to replace minhook with something like funchook)
• It is completely open source and under the MIT license, everybody is welcome to contribute
• easy build system adjustments

So whoever wants to support a native linux build, get in touch!


With that said, I will of course keep the ~4 native linux extension devs out there in mind with feature releases.

[beko]

Nope, don't see it but hey it's your party

The X4RestServer did pull it off before too but that went nowhere for years.

Guess I'll stick with my socket approach.

[eg3r]

Nope, don't see it but hey it's your party

The X4RestServer did pull it off before too but that went nowhere for years.

Guess I'll stick with my socket approach.

Hi, I see.

My point is, you certainly can "pull it off". But there are time and resource constrains on me to do so.

Thank you for the discussion.