From 528fee377446af407fc34a7ac0a662bdb91202aa Mon Sep 17 00:00:00 2001
From: Shariff Faleel <shariff.mfa@outlook.com>
Date: Wed, 13 Dec 2023 14:50:06 -0800
Subject: [PATCH] Adding HandJointData

---
 Runtime/Tracking.meta                  |   8 +
 Runtime/Tracking/HandJointData.cs      | 225 +++++++++++++++++++++++++
 Runtime/Tracking/HandJointData.cs.meta |  11 ++
 Runtime/ubc.ok.ovilab.HPUI.asmdef      |   4 +-
 4 files changed, 247 insertions(+), 1 deletion(-)
 create mode 100644 Runtime/Tracking.meta
 create mode 100644 Runtime/Tracking/HandJointData.cs
 create mode 100644 Runtime/Tracking/HandJointData.cs.meta

diff --git a/Runtime/Tracking.meta b/Runtime/Tracking.meta
new file mode 100644
index 0000000..4972631
--- /dev/null
+++ b/Runtime/Tracking.meta
@@ -0,0 +1,8 @@
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+guid: c5420efcd478c5d4f971a34a520329ed
+folderAsset: yes
+DefaultImporter:
+  externalObjects: {}
+  userData: 
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diff --git a/Runtime/Tracking/HandJointData.cs b/Runtime/Tracking/HandJointData.cs
new file mode 100644
index 0000000..c9c965a
--- /dev/null
+++ b/Runtime/Tracking/HandJointData.cs
@@ -0,0 +1,225 @@
+using System;
+using System.Collections.Generic;
+using UnityEngine;
+using UnityEngine.XR.Hands;
+
+namespace ubco.ovi.HPUI.Core
+{
+    /// <summary>
+    /// Utility class to expose joint data accessible.
+    /// </summary>
+    public class HandJointData: MonoBehaviour
+    {
+        private XRHandSubsystem handSubsystem;
+        private List<JointDataEventHandler> jointDataEvents;
+
+        #region Unity events
+        /// <summary>
+        /// See <see cref="MonoBehaviour"/>.
+        /// </summary>
+        protected void Start()
+        {
+            // Initializing all the hand joint events
+            for (int i = XRHandJointIDUtility.ToIndex(XRHandJointID.BeginMarker); i < XRHandJointIDUtility.ToIndex(XRHandJointID.EndMarker); i++)
+            {
+                jointDataEvents.Add(new JointDataEventHandler(XRHandJointIDUtility.FromIndex(i), Handedness.Left));
+                jointDataEvents.Add(new JointDataEventHandler(XRHandJointIDUtility.FromIndex(i), Handedness.Right));
+            }
+        }
+
+        /// <summary>
+        /// See <see cref="MonoBehaviour"/>.
+        /// </summary>
+        protected void OnDisable()
+        {
+            if (handSubsystem != null)
+            {
+                handSubsystem.trackingAcquired -= OnTrackingAcquired;
+                handSubsystem.trackingLost -= OnTrackingLost;
+                handSubsystem.updatedHands -= OnUpdatedHands;
+                handSubsystem = null;
+            }
+        }
+
+        /// <summary>
+        /// See <see cref="MonoBehaviour"/>.
+        /// </summary>
+        protected void Update()
+        {
+            if (handSubsystem != null && handSubsystem.running)
+            {
+                return;
+            }
+            
+            List<XRHandSubsystem> handSubsystems = new List<XRHandSubsystem>();
+            SubsystemManager.GetSubsystems(handSubsystems);
+            bool foundRunningHandSubsystem = false;
+            for (var i = 0; i < handSubsystems.Count; ++i)
+            {
+                XRHandSubsystem handSubsystem = handSubsystems[i];
+                if (handSubsystem.running)
+                {
+                    UnsubscribeHandSubsystem();
+                    this.handSubsystem = handSubsystem;
+                    foundRunningHandSubsystem = true;
+                    break;
+                }
+            }
+
+            if (!foundRunningHandSubsystem)
+            {
+                return;
+            }
+            
+            SubscribeHandSubsystem();
+        }
+        #endregion
+
+        #region event handling
+        /// <summary>
+        /// Subscribe to events on the <see cref="XRHandSubsystem"/>
+        /// </summary>
+        private void SubscribeHandSubsystem()
+        {
+            if (handSubsystem == null)
+                return;
+
+            handSubsystem.trackingAcquired += OnTrackingAcquired;
+            handSubsystem.trackingLost += OnTrackingLost;
+            handSubsystem.updatedHands += OnUpdatedHands;
+        }
+
+        /// <summary>
+        /// Unsubscribe from events on the <see cref="XRHandSubsystem"/>
+        /// </summary>
+        private void UnsubscribeHandSubsystem()
+        {
+            if (handSubsystem == null)
+                return;
+
+            handSubsystem.trackingAcquired -= OnTrackingAcquired;
+            handSubsystem.trackingLost -= OnTrackingLost;
+            handSubsystem.updatedHands -= OnUpdatedHands;
+        }
+
+        /// <summary>
+        /// Event callback for <see cref="XRHandSubsystem.updatedHands"/>
+        /// </summary>
+        private void OnUpdatedHands(XRHandSubsystem subsystem,
+                                    XRHandSubsystem.UpdateSuccessFlags updateSuccessFlags,
+                                    XRHandSubsystem.UpdateType updateType)
+        {
+            switch (updateType)
+            {
+                case XRHandSubsystem.UpdateType.Dynamic:
+                    // Update game logic that uses hand data
+                    break;
+                case XRHandSubsystem.UpdateType.BeforeRender:
+                    foreach (JointDataEventHandler handler in jointDataEvents)
+                    {
+                        if (handler.handedness == Handedness.Left)
+                        {
+                            handler.ProcessEvent(subsystem.leftHand);
+                        }
+                        else if (handler.handedness == Handedness.Right)
+                        {
+                            handler.ProcessEvent(subsystem.rightHand);
+                        }
+                    }
+                    break;
+            }
+        }
+
+        /// <summary>
+        /// Event callback for <see cref="XRHandSubsystem.trackingAcquired"/>
+        /// </summary>
+        private void OnTrackingAcquired(XRHand hand)
+        {
+        }
+
+        /// <summary>
+        /// Event callback for <see cref="XRHandSubsystem.trackingLost"/>
+        /// </summary>
+        private void OnTrackingLost(XRHand hand)
+        {
+        }
+        #endregion
+
+        #region public interface
+        /// <summary>
+        /// Subscribe to a joint on a hand
+        /// </summary>
+        public void SubscribeToJointDataEvent(Handedness handedness, XRHandJointID joinID, EventHandler<JointDataEventArgs> callback)
+        {
+            foreach(JointDataEventHandler handler in jointDataEvents)
+            {
+                if (handler.handedness == handedness && handler.jointID == joinID)
+                {
+                    handler.jointDataEventHandler += callback;
+                }
+            }
+        }
+
+        /// <summary>
+        /// Unsubscribe to a joint on a hand
+        /// </summary>
+        public void UnsubscribeToJointDataEvent(Handedness handedness, XRHandJointID joinID, EventHandler<JointDataEventArgs> callback)
+        {
+            foreach(JointDataEventHandler handler in jointDataEvents)
+            {
+                if (handler.handedness == handedness && handler.jointID == joinID)
+                {
+                    handler.jointDataEventHandler += callback;
+                }
+            }
+        }
+        #endregion
+    }
+
+    /// <summary>
+    /// Event args for joint data
+    /// </summary>
+    public class JointDataEventArgs: EventArgs
+    {
+        public Pose pose;
+        public Handedness handedness;
+        public XRHandJointID jointID;
+
+        public JointDataEventArgs(Pose pose, Handedness handedness, XRHandJointID jointID)
+        {
+            this.pose = pose;
+            this.handedness = handedness;
+            this.jointID = jointID;
+        }
+    }
+
+    /// <summary>
+    /// Helper to push the pose data for a joint
+    /// </summary>
+    internal class JointDataEventHandler
+    {
+        public XRHandJointID jointID;
+        public Handedness handedness;
+        public EventHandler<JointDataEventArgs> jointDataEventHandler;
+
+        public JointDataEventHandler(XRHandJointID jointID, Handedness handedness)
+        {
+            this.jointID = jointID;
+            this.handedness = handedness;
+        }
+
+        public void ProcessEvent(XRHand hand)
+        {
+            EventHandler<JointDataEventArgs> handler = jointDataEventHandler;
+            if (handler != null)
+            {
+                XRHandJoint joint = hand.GetJoint(jointID);
+                
+                if (joint.TryGetPose(out Pose resultingPose))
+                {
+                    handler(this, new JointDataEventArgs(resultingPose, handedness, jointID));
+                }
+            }
+        }
+    }
+}
diff --git a/Runtime/Tracking/HandJointData.cs.meta b/Runtime/Tracking/HandJointData.cs.meta
new file mode 100644
index 0000000..41f1012
--- /dev/null
+++ b/Runtime/Tracking/HandJointData.cs.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: 38299689a440c8e4fab0a65d2117c10b
+MonoImporter:
+  externalObjects: {}
+  serializedVersion: 2
+  defaultReferences: []
+  executionOrder: 0
+  icon: {instanceID: 0}
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
diff --git a/Runtime/ubc.ok.ovilab.HPUI.asmdef b/Runtime/ubc.ok.ovilab.HPUI.asmdef
index 0716e27..b962f08 100644
--- a/Runtime/ubc.ok.ovilab.HPUI.asmdef
+++ b/Runtime/ubc.ok.ovilab.HPUI.asmdef
@@ -1,7 +1,9 @@
 {
     "name": "ubc.ok.ovilab.HPUI",
     "rootNamespace": "ubc.ok.ovilab.HPUI",
-    "references": [],
+    "references": [
+        "Unity.XR.Hands"
+    ],
     "includePlatforms": [],
     "excludePlatforms": [],
     "allowUnsafeCode": false,