Process joints

If you wish to process or filter joint data before it's returned to the subsystem caller, derive a class from IXRHandProcessor and register it with XRHandSubsystem.RegisterProcessor in a static method decorated with [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.SubsystemRegistration)]. IXRHandProcessors with a lower callbackOrder value will be called sooner than this with higher values for their callbackOrder.

If you wish to access the joint data before anyone has had a chance to process the joints, you can use XRHandSubsystem.preprocessJoints.

Note

This is an advanced use case. Typically, you should use the XRHandSubsystem's updatedHands callback and just consume the data instead of altering it in any way.

Use extension methods in UnityEngine.XR.Hands.Processing.XRHandProcessingUtility. The below sample code demonstrates how to set pose data before it's returned to the subsystem.

using UnityEngine.XR.Hands.Processing;

public class MyHandProcessor : MonoBehaviour, IXRHandProcessor
{
    public int callbackOrder => 0;

    public void ProcessJoints(XRHandSubsystem subsystem, XRHandSubsystem.UpdateSuccessFlags successFlags, XRHandSubsystem.UpdateType updateType)
    {
        var leftHand = subsystem.leftHand;
        leftHand.SetRootPose(Pose.identity);
        subsystem.SetCorrespondingHand(leftHand);

        var rightHand = subsystem.rightHand;
        rightHand.SetRootPose(Pose.identity);
        subsystem.SetCorrespondingHand(rightHand);

        var leftJoints = leftHand.GetRawJointArray();
        var rightJoints = rightHand.GetRawJointArray();
        for (int jointIndex = 0; jointIndex < leftJoints.Length; ++jointIndex)
        {
            var leftJoint = leftJoints[jointIndex];
            leftJoint.SetPose(Pose.identity);
            leftJoints[jointIndex] = leftJoint;

            var rightJoint = rightJoints[jointIndex];
            rightJoint.SetPose(Pose.identity);
            rightJoints[jointIndex] = rightJoint;
        }
    }

    void Update()
    {
        if (m_Registered)
            return;

        SubsystemManager.GetSubsystems(s_SubsystemsReuse);
        if (s_SubsystemsReuse.Count == 0)
            return;

        m_Subsystem = s_SubsystemsReuse[0];
        m_Subsystem.RegisterProcessor(this);
        m_Registered = true;
    }

    void OnDisable()
    {
        if (m_Subsystem != null)
        {
            m_Subsystem.UnregisterProcessor(this);
            m_Subsystem = null;
            m_Registered = false;
        }
    }

    bool m_Registered;
    XRHandSubsystem m_Subsystem;

    static List<XRHandSubsystem> s_SubsystemsReuse = new List<XRHandSubsystem>();
}

See sample HandProcessor script in the HandVisualizer sample for a more useful example of how to use this functionality.