Unity fractal server sample

The Unity-FractalStream sample is a server sample built in Unity that supports mono and stereo rendering.

Native Plugin

Unity-FractalStream consumes a native plugin that is produced by the 3D Streaming Toolkit build pipeline. As such it’s critical to first build 3dtoolkit before attempting to use the sample (see Building below).

The native plugin is responsible for negotiating with clients to configure a stream, and for encoding and sending visual frame data from Unity to a connected client. All of our scripting in Unity is designed to abstract and facilitate communication with this native module.


Mutable state is just what it sounds like - a lightweight abstraction around mutable data that is used to represent data surfaced from the native plugin within Unity. The component that powers this is PeerListState. PeerListState is a simple ScriptableObject that represents a collection of peers (potential clients) as well as an optional currently selected peer. To create an instance of a PeerListState, you simply navigate to Assets -> Create -> PeerListState. This will add an asset to the project that represents a particular mutable state. The instance can be wired to scripts (like WebRTCServer) in the editor by dragging it to a field.

Unity-FractalStream ships with a basic menu implementation that allows a user to interactively select a peer to connect to. This menu is powered by Unity-MenuStack which provides a framework for quickly building out menu systems using Unity’s built in UI System. Combined with two scripts (PeerListDropdownAdapter and DropdownSelectorButton) we’re able to build a UI that interacts with a PeerListState instance.


Unity-FractalStream ships with two prefabs that enable quick buildouts of WebRTC capable scenes. StereoCapableCameraHead represents a mono/stereo capable camera system with a WebRTCServer component that enables frame encoding and connectivity. Use this component instead of a traditional main Camera to power your scene rendering. MenuRoot represents the menu system that enables interactive selection of peers. Use this component if your scene should allow the user to connect to peers, rather than waiting for a peer to connect to it.


There are a handful of Unity scripts that enable our sample experience. We’ll briefly cover the roles and responsibilities of each, below.





Note: if you’re building a new experience, these can be ignored.


Note: Unity-FractalStream requires Unity 2017.4.4f1 LTS or higher (we test at 2017.4.4f1 LTS)

Note: Unity-FractalStream requires that the 3D Streaming Toolkit solution is built first, to create the needed native plugins

How it works

Once the config settings are changed, the server will require a client to connect to. In this toolkit, we have a few Sample Clients.

When both the client and server are connected to the same signaling server, they will appear in the peer list.

You can initiate the connection using the client or server, simply select the peer from the list and press join. That will start the video streaming and you can use the controls for that specific client to interact with the scene.