Merge pull request #3946 from Railboy/mrtk_gc_alloc_fixes

Removes GC Alloc from various services

Author: wiwei

Assets/MixedRealityToolkit.Providers/WindowsMixedReality/WindowsMixedRealityDeviceManager.cs

@@ -42,6 +42,12 @@ public WindowsMixedRealityDeviceManager(
 
 #if UNITY_WSA
 
+        /// <summary>
+        /// The max expected sources is two - two controllers and/or two hands.
+        /// We'll set it to 20 just to be certain we can't run out of sources.
+        /// </summary>
+        public const int MaxInteractionSourceStates = 20;
+
         /// <summary>
         /// Dictionary to capture all active controllers detected
         /// </summary>
@@ -50,7 +56,12 @@ public WindowsMixedRealityDeviceManager(
         /// <summary>
         /// Cache of the states captured from the Unity InteractionManager for UWP
         /// </summary>
-        InteractionSourceState[] interactionmanagerStates;
+        InteractionSourceState[] interactionmanagerStates = new InteractionSourceState[MaxInteractionSourceStates];
+
+        /// <summary>
+        /// The number of states captured most recently
+        /// </summary>
+        private int numInteractionManagerStates;
 
         /// <summary>
         /// The current source state reading for the Unity InteractionManager for UWP
@@ -277,12 +288,12 @@ public override void Enable()
             InteractionManager.InteractionSourcePressed += InteractionManager_InteractionSourcePressed;
             InteractionManager.InteractionSourceReleased += InteractionManager_InteractionSourceReleased;
 
-            interactionmanagerStates = InteractionManager.GetCurrentReading();
+            numInteractionManagerStates = InteractionManager.GetCurrentReading(interactionmanagerStates);
 
             // Avoids a Unity Editor bug detecting a controller from the previous run during the first frame
 #if !UNITY_EDITOR
             // NOTE: We update the source state data, in case an app wants to query it on source detected.
-            for (var i = 0; i < interactionmanagerStates?.Length; i++)
+            for (var i = 0; i < numInteractionManagerStates; i++)
             {
                 var controller = GetController(interactionmanagerStates[i].source);
 
@@ -307,9 +318,9 @@ public override void Update()
         {
             base.Update();
 
-            interactionmanagerStates = InteractionManager.GetCurrentReading();
+            numInteractionManagerStates = InteractionManager.GetCurrentReading(interactionmanagerStates);
 
-            for (var i = 0; i < interactionmanagerStates?.Length; i++)
+            for (var i = 0; i < numInteractionManagerStates; i++)
             {
                 // SourceDetected gets raised when a new controller is detected and, if previously present, 
                 // when OnEnable is called. Do not create a new controller here.

Assets/MixedRealityToolkit.SDK/Features/UX/Scripts/Pointers/DefaultPointerMediator.cs

@@ -11,6 +11,7 @@ public class DefaultPointerMediator : IMixedRealityPointerMediator
         private readonly HashSet<IMixedRealityPointer> farInteractPointers = new HashSet<IMixedRealityPointer>();
         private readonly HashSet<IMixedRealityNearPointer> nearInteractPointers = new HashSet<IMixedRealityNearPointer>();
         private readonly HashSet<IMixedRealityTeleportPointer> teleportPointers = new HashSet<IMixedRealityTeleportPointer>();
+        private readonly HashSet<IMixedRealityPointer> unassignedPointers = new HashSet<IMixedRealityPointer>();
         private readonly Dictionary<IMixedRealityInputSource, HashSet<IMixedRealityPointer>> pointerByInputSourceParent = new Dictionary<IMixedRealityInputSource, HashSet<IMixedRealityPointer>>();
 
         public void RegisterPointers(IMixedRealityPointer[] pointers)
@@ -91,7 +92,11 @@ public void UpdatePointers()
             }
 
             // pointers whose active state has not yet been set this frame
-            HashSet<IMixedRealityPointer> unassignedPointers = new HashSet<IMixedRealityPointer>(allPointers);
+            unassignedPointers.Clear();
+            foreach (IMixedRealityPointer unassignedPointer in allPointers)
+            {
+                unassignedPointers.Add(unassignedPointer);
+            }
 
             // If any pointers are locked, they have priority. 
             // Deactivate all other pointers that are on that input source

Assets/MixedRealityToolkit.Services/InputSimulation/SimulatedHandDataProvider.cs

@@ -159,6 +159,9 @@ public class SimulatedHandDataProvider
         // Last timestamp when hands were tracked
         private long lastSimulatedTimestampLeft = 0;
         private long lastSimulatedTimestampRight = 0;
+        // Cached delegates for hand joint generation
+        private SimulatedHandData.HandJointDataGenerator generatorLeft;
+        private SimulatedHandData.HandJointDataGenerator generatorRight;
 
         public SimulatedHandDataProvider(MixedRealityInputSimulationProfile _profile)
         {
@@ -185,8 +188,20 @@ public bool UpdateHandData(SimulatedHandData handDataLeft, SimulatedHandData han
             // TODO: DateTime.UtcNow can be quite imprecise, better use Stopwatch.GetTimestamp
             // https://stackoverflow.com/questions/2143140/c-sharp-datetime-now-precision
             long timestamp = DateTime.UtcNow.Ticks;
-            handDataChanged |= handDataLeft.UpdateWithTimestamp(timestamp, HandStateLeft.IsTracked, HandStateLeft.IsPinching, HandStateLeft.FillCurrentFrame);
-            handDataChanged |= handDataRight.UpdateWithTimestamp(timestamp, HandStateRight.IsTracked, HandStateRight.IsPinching, HandStateRight.FillCurrentFrame);
+
+            // Cache the generator delegates so we don't gc alloc every frame
+            if (generatorLeft == null)
+            {
+                generatorLeft = HandStateLeft.FillCurrentFrame;
+            }
+
+            if (generatorRight == null)
+            {
+                generatorRight = HandStateRight.FillCurrentFrame;
+            }
+
+            handDataChanged |= handDataLeft.UpdateWithTimestamp(timestamp, HandStateLeft.IsTracked, HandStateLeft.IsPinching, generatorLeft);
+            handDataChanged |= handDataRight.UpdateWithTimestamp(timestamp, HandStateRight.IsTracked, HandStateRight.IsPinching, generatorRight);
 
             return handDataChanged;
         }

Assets/MixedRealityToolkit/Providers/UnityInput/UnityTouchDeviceManager.cs

@@ -41,7 +41,8 @@ public UnityTouchDeviceManager(
         /// <inheritdoc />
         public override void Update()
         {
-            for (var i = 0; i < UInput.touches.Length; i++)
+            int touchCount = UInput.touchCount;
+            for (var i = 0; i < touchCount; i++)
             {
                 Touch touch = UInput.touches[i];