The Tobii EyeX Plugin for Unreal Engine 4 makes it possible to create games that the player can interact with using her eyes. It does that by integrating the Tobii EyeX Engine API into the Unreal Engine development environment.

The plugin can be inserted into any game built with the Unreal Engine 4 and used from both Blueprints and C++ code.

• A Tobii EyeX Dev Kit or other compatible Tobii eye tracker, such as the Tobii REX or Tobii X2-30.
• Unreal Engine 4.5 or above.
• Visual Studio 2013. Tested with Professional edition; we think it also should work fine with the free Visual Studio 2013 Express Windows Desktop edition.

1. Take a look at the developer's guide in this package. Just read through the introduction: there's plenty of useful information in there and we don't want to repeat it here.

2. Check out the 4.5 or 4.6 branch of EpicGames/UnrealEngine, or your fork of choice, from GitHub. Download and install the required files as described in the readme file in the UnrealEngine repository, but don't start the build just yet.

   Alternatively, if you use an installed version of the Unreal Engine, you can skip steps 2-4.

3. Optionally merge the pull request https://github.com/EpicGames/UnrealEngine/pull/582.
   This removes the offset error that is present when the game starts. The workaround is to move the mouse pointer over the viewport.

4. Build the Unreal Engine as described in its readme file.

5. Clone or download this repository from GitHub. Download the EyeX SDK for C/C++ from developer.tobii.com. Extract the files and copy the lib and include directories to Plugins/TobiiEyeX/ThirdParty/EyeX. Note that the SDK license differs from the one used for this plugin.

6. Locate the EyeXSamples.uproject file in the EyeX Plugin package. Right- click and select Generate Visual Studio project files. Open the Visual Studio solution file that appears. Build and run the sample project (EyeXSamples). The EyeXSamples editor should launch. Click play to start the samples.

7. To import the plugin into your own game project:

   • Create a new directory in your Unreal project directory called "Plugins".
   • Copy the contents of the Plugins directory in this repository into that directory.
   • Start the editor and open the plugin viewer (can be found in the Windows->Plugins menu).
   • Add a reference to the module in your build script (MYPROJECT.Build.cs). The relevant row might look something like: PublicDependencyModuleNames.AddRange(new string[] { "Core", "CoreUObject", "Engine", "InputCore", "TobiiEyeX" });

8. Use the plugin through the EyeX function library (Blueprints) and/or the IEyeXPlugin interface (C++).

HAVE FUN!!!

If you have problems, questions, ideas, or suggestions, please use the forums on the Tobii Developer Zone.

The master branch has been tested against Unreal Engine 4.5 and 4.6. More branches will be added later on.

You're always welcome to submit a Pull Request on GitHub.

By contributing code to this project, you agree to license your contributed code under the same terms as the rest of the source code in the repository.

• 4 Dec 2014: First public release.

• Tim Lindeberg
• The Tobii developer communications team
• Fredrik Lindh (@Temaran), who set the ball rolling
• Special thanks to @getnamo whose unofficial Hydra plugin has been very useful as a working example of plugin code.