Implement a provider

To implement a provider for the subsystem in this package (for example, say you are a hardware manufacturer for a new XR device), Unity recommends that your implementation inherit from XRHandSubsystem if you have platform-specific data you wish to surface. This subsystem base class has a corresponding abstract class called XRHandSubsystemProvider, which is the primary interface you must implement to support on your platform.

Subsystem implementations should be independent from each other. For example, your implementation of the XRHandSubsystem should have the same behavior whether or not other subsystem implementations are also active in a user's scene.

Register a subsystem descriptor

Each subsystem type has a corresponding subsystem descriptor type. Your provider should create and register a subsystem descriptor instance with Unity's SubsystemManager to enable runtime discovery and activation of subsystems. To register your subsystem descriptor, include a static void method with the [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.SubsystemRegistration)] attribute as shown in the example below, and in it call XRHandSubystemDescriptor.Register with subsystem descriptor information you are registering.

// This class defines a hand subsystem provider
class MyHandProvider : XRHandSubsystemProvider
{
    // ...
}

// This class defines a hand subsystem
class MyHandSubsystem : XRHandSubsystem
{
    public int myPlatformSpecificData => provider.RetrievePlatformSpecificData();

    // This method registers the subsystem descriptor with the SubsystemManager
    [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.SubsystemRegistration)]
    static void RegisterDescriptor()
    {
        var handsSubsystemCinfo = new XRHandSubsystemDescriptor.Cinfo
        {
            id = "My-Hands",
            providerType = typeof(MyHandProvider),
            subsystemTypeOverride = typeof(MyHandSubsystem)
        };
        XRHandSubsystemDescriptor.Register(handsSubsystemCinfo);
    }
}

Implement an XR Loader

An XRLoader is responsible for creating and destroying subsystem instances based on the settings found in Project Settings > XR Plug-in Management. All provider plug-ins must implement an XRLoader. For more information on authoring an XRLoader, see the XR Plug-in Management provider documentation.