by Hotride

Hotride / OrionUO

Orion - Ultima Online graphic client, using OpenGL for rendering

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The public version in all repositories of the project is temporarily not updated.

New Launcher (x32 or x64) can be downloaded from here

To fix missing api-ms-win-crt-runtime-l1-1-0.dll errors on Win 7 SP 1:

Download and install update: KB2999226

OrionUO Client

Travis Build Status Build status

  • OrionUO Client - is an alternative, open source Ultima Online graphic client.

  • Platforms: Windows and Linux (in progress)

  • Rendering: OpenGL 2.0 and higher

Orion Community



github issue tracking


Other Orion Projects

Building OrionUO

This project requires CMake 3.7 to build. It currently supports Visual Studio 2015, 2017, GCC 7.0 and Clang 6.


On Windows, to generate the Visual Studio solution, go inside your cloned OrionUO folder and do:

md build
cd build
cmake -G "Visual Studio 2017" ..

This will build a 32bits executable. If you do want 64bits, you can do

cmake -G "Visual Studio 2017 Win64" ..
instead. Note that plugins are still unsupported in the 64bits client.

Or, you can use CMake-GUI to configure and generate the solution.

  • If you want to help converting OrionUO to SDL, you can disable
    option in CMake. This option enables the original client implementation in pure win32 API and is kept as a reference implementation to use during the client conversion to SDL.

Linux (in progress)

$ mkdir build
$ cd build
$ cmake -G Ninja .. -DCMAKE_BUILD_TYPE=Release
$ ninja OrionUO_unity -j8
$ ./OrionUO/unity/OrionUO

You'll need a

and a
in the working directory. Inside
you can add a line
, so Orion will be able to find your original client data files.


See the project planning here to find tasks on which you can help.

More detailed contribution documentation soon


Hotride (Author)


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WebMoney: R644829964694 Z983232789532 E400319624386

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