An open-source Asheron's Call client for .NET 10.
The original game's behavior, in a codebase built to be worked on.
OpenAC is a from-scratch client for Asheron's Call that reproduces the observable behavior of the original client in a C# codebase built to be read, tested, and changed. It renders with Vulkan through Silk.NET, talks to ACEmulator servers over the game's wire protocol, and exposes a plugin API the original never had.
OpenAC does not ship any game data. You supply your own data files.
OpenAC is in beta: it is fully playable against an ACEmulator server, and it is under active development. Expect bugs, plenty of them; the perfect is the enemy of the good, and this is out so people can play it and report what breaks. Today it does the following:
- Log in, create and select characters, enter the world, and log out cleanly.
- Stream the outdoor world, towns, buildings, cellars, and dungeons with the original terrain, scenery, lighting, sky, weather, and day/night cycle.
- Move, jump, and collide the way the original client did, including slopes, stairs, doorways, and portal travel.
- Melee, bows, crossbows, and the complete late-era spell catalog with components, enchantments, projectiles, and effects.
- Inventory, equipment, containers, corpse looting, vendors, secure trade, item use, assessment, and the familiar quick bars.
- Chat with the original channels, colors, and the slash commands.
- The original UI: vitals, options, character, spellbook, fellowship and allegiance panels, radar, dialogs, and floating windows.
- A headless host that runs the same game runtime without a window, for bots and automated testing, on Windows and Linux.
- Plugins, installed from the launcher, with a plugin manager that finds and updates them.
Found a bug or missing feature? Please report it in Discord or open a GitHub issue. Include your OpenAC version, what you did, what happened, and a screenshot if you can. Reports from players help us decide what to fix next.
Platforms. Windows and Linux, 64-bit, and macOS on Apple silicon, for the launcher, graphical client, and headless host. Windows is where most of the play-testing happens; the Linux and macOS clients are newer and have had less time in front of players, so reports from those desktops are especially welcome.
- Linux in CI. The Linux graphical client builds, installs through the launcher, and plays, but CI runs its rendering tests on Windows hardware only. A Linux rendering lane is next.
- macOS distribution. Add Developer ID signing and notarization to the Apple-silicon launcher packages.
- Performance tuning. Improve frame times, world streaming, memory use, and responsiveness.
- Housing.
- A documented plugin API.
Grab the launcher for your platform from the latest release, unzip it anywhere, and run it:
| Platform | Download | Run |
|---|---|---|
| Windows | launcher-win-x64.zip |
acdream-launcher.exe |
| Linux | launcher-linux-x64.zip |
./acdream-launcher |
| macOS (Apple silicon) | launcher-osx-arm64.zip |
Drag OpenAC.app to ~/Applications, then open it in Finder. |
The launcher installs the client, prepares your data files, keeps itself and the client up to date, and stores your server and character profiles.
You will need:
- Windows 10 or 11, or a 64-bit Linux desktop (X11 or Wayland), with a Vulkan 1.3 capable GPU and driver.
- Your own Asheron's Call data files (
client_portal.dat,client_cell_1.dat,client_highres.dat,client_local_English.dat). - A server to connect to. OpenAC speaks ACEmulator's protocol; a local ACE server works well for trying it out.
Requires the .NET 10 SDK (the exact band is pinned in global.json).
git clone https://github.com/eriknihlen/OpenAC.git
cd OpenAC
dotnet build AcDream.slnx -c Release
dotnet test AcDream.slnx -c Release --no-build --filter "Lane!=InstalledDat&Lane!=PreparedPackage&Lane!=Live&Lane!=Manual&Lane!=Timing&Lane!=Windows&Lane!=Linux&Lane!=Vulkan&Lane!=SystemFont&Purpose!=Diagnostic&Status!=KnownFailure"Then see docs/building-and-running.md for preparing your data files and launching the client or the headless host against a server.
Plugins are .NET assemblies that target AcDream.Plugin.Abstractions, a
small BCL-only contract: game state, events, commands, and a markup-based UI
panel system that renders in the game's own look.
Start with docs/plugin-development.md: project setup, the manifest, where plugins install, and what the API promises. docs/plugin-api.md describes every surface (game state, items, chat, trade, vendor, hotkeys, window, headless) and docs/plugin-ui-markup.md the in-game panels. Every public member of the contract carries a summary that your IDE shows, and the same summaries make up the API reference site.
Plugins live in their own repositories and install into the client's plugins folder; OpenAC-MagTools and openac-mosstank are external plugins built that way. The same plugin runs unchanged in the headless host for bots and tests.
Shipping one to other players goes through the launcher: publish a GitHub release it can install, check it first with the bundled validator so you know it meets the current rules, and ask for a listing so it shows up in the launcher's Discover panel. docs/plugin-development.md walks the whole path and docs/plugin-manifest.md is the field-by-field contract, including the icon rules, the size caps, beta releases, and the capabilities a plugin declares before a player installs it.
MossTank is a re-implementation of VirindiTank, the automation plugin most Asheron's Call players ran for years. It reads VirindiTank's own profile and navigation files so existing setups carry over, and it aims at the same tabs, the same behavior, and the same vocabulary. Full credit to Virindi for the original; MossTank exists because that design was right. It lives in its own repository and installs from the launcher's plugin manager like any other plugin.
Custom shader packs are an experiment. The render packs under samples/
are plugins that swap in their own shader stages (an atmospheric tier, a
shadows-only tier, a no-op pack), and they exist so people can play with the
rendering pipeline without touching the client. Try them, break them, and
say what you found. They can be enabled in game under the graphics settings.
This is a heavily AI-assisted project, and it says so openly. Most of the code was written by AI tools working under the maintainer's direction and supervision. Not every line has been read by a human. What every change has to pass instead is the same gate: it builds with warnings as errors, it passes the test suite (about 18,000 tests in CI), it survives an independent AI review pass, and it behaves like the original game when the maintainer plays it. The AI is a tool here, not the author of record; the person who merges a change answers for it.
The project welcomes AI-assisted contributions on exactly those terms. Use whatever tools you like; submit changes you understand, that build, that pass the tests, and that you can explain in the pull request.
OpenAC is meant to be built by the community, not by one person. The code is shared so that anyone who cares about Asheron's Call can read it, run it, change it, and ship it. Contributions of every size are wanted: a typo, a bug report with a screenshot, a plugin, a port to a new platform, or a whole subsystem. If you have played the game and something feels wrong, that observation alone is useful.
- Read CONTRIBUTING.md for the ground rules and how to get a build running.
- Join Discord to report bugs, share screenshots, and discuss what you find while playing. You do not need a GitHub account to help us improve the client.
- Ask questions and float ideas in Discussions.
- File bugs and feature requests in Issues.
- Fork it. The MIT license means you never need permission.
OpenAC stands on the work of the Asheron's Call preservation community: ACEmulator for the server and protocol, WorldBuilder and Chorizite for the data-file and rendering foundation this project extracted and adapted, ACViewer for the viewer that answered many rendering questions, and holtburger for a working reference of client behavior, and Virindi, whose VirindiTank defined what an Asheron's Call automation plugin should be. Rendering, windowing, and audio go through Silk.NET.
OpenAC is released under the MIT License. Third-party notices are in NOTICE.md.
Asheron's Call and all associated names, art, and data files are the property of their respective owners. This project distributes no game assets and is not affiliated with Microsoft, Turbine, or Warner Bros. Entertainment.
From Sweden with love 🇸🇪