fix: owner authoritative parenting backport (#3453)

This PR backports the the `NetworkObject.SyncOwnerTransformWhenParented`
and `NetworkObject.AllowOwnerToParent` functionality.

[MTTB-1284](https://jira.unity3d.com/browse/MTTB-1284)

fix: #2842

## Changelog

- Added: `NetworkObject.SyncOwnerTransformWhenParented` which will not
synchronize transform values sent by the server when parented (primarily
for owner authoritative motion models).
- Added: `NetworkObject.AllowOwnerToParent` which allows a client owner
to parent locally and have the changes synchronize with the server and
other clients (primarily for owner authoritative motion models).


## Testing and Documentation

- Includes backported integration test modified to the constraints of
v1.x.
- Includes additions to public API documentation.

<!-- Uncomment and mark items off with a * if this PR deprecates any
API:
### Deprecated API
- [ ] An `[Obsolete]` attribute was added along with a `(RemovedAfter
yyyy-mm-dd)` entry.
- [ ] An [api updater] was added.
- [ ] Deprecation of the API is explained in the CHANGELOG.
- [ ] The users can understand why this API was removed and what they
should use instead.
-->

## Backport

No back port needed as this is a targeted backport of certain v2.x
features that could be useful to projects still using v1.x.

---------

Co-authored-by: Emma <[email protected]>

Author: NoelStephensUnity

com.unity.netcode.gameobjects/Runtime/Core/NetworkObject.cs

@@ -417,6 +417,24 @@ private GlobalObjectId GetGlobalId()
         /// </summary>
         public bool AutoObjectParentSync = true;
 
+        /// <summary>
+        /// Determines if the owner will apply transform values sent by the parenting message.
+        /// </summary>
+        /// <remarks>
+        /// When enabled, the resultant parenting transform changes sent by the authority will be applied on all instances. <br />
+        /// When disabled, the resultant parenting transform changes sent by the authority will not be applied on the owner's instance. <br />
+        /// When disabled, all non-owner instances will still be synchronized by the authority's transform values when parented.
+        /// </remarks>
+        [Tooltip("When disabled (default enabled), the owner will not apply a server or host's transform properties when parenting changes. Primarily useful for client-server network topology configurations.")]
+        public bool SyncOwnerTransformWhenParented = true;
+
+        /// <summary>
+        /// Client-Server specific, when enabled an owner of a NetworkObject can parent locally as opposed to requiring the owner to notify the server it would like to be parented.
+        /// This behavior is always true when using a distributed authority network topology and does not require it to be set.
+        /// </summary>
+        [Tooltip("When enabled (default disabled), owner's can parent a NetworkObject locally without having to send an RPC to the server or host. Only pertinent when using client-server network topology configurations.")]
+        public bool AllowOwnerToParent;
+
         internal readonly HashSet<ulong> Observers = new HashSet<ulong>();
 
 #if MULTIPLAYER_TOOLS
@@ -1086,8 +1104,9 @@ public bool TrySetParent(NetworkObject parent, bool worldPositionStays = true)
             {
                 return false;
             }
-
-            if (!NetworkManager.IsServer && !NetworkManager.ShutdownInProgress)
+            // If we don't have authority and we are not shutting down, then don't allow any parenting.
+            // If we are shutting down and don't have authority then allow it.
+            if (!(NetworkManager.IsServer || (AllowOwnerToParent && IsOwner)) && !NetworkManager.ShutdownInProgress)
             {
                 return false;
             }
@@ -1102,6 +1121,8 @@ public bool TrySetParent(NetworkObject parent, bool worldPositionStays = true)
                 return false;
             }
 
+
+
             m_CachedWorldPositionStays = worldPositionStays;
 
             if (parent == null)
@@ -1135,7 +1156,9 @@ private void OnTransformParentChanged()
                 return;
             }
 
-            if (!NetworkManager.IsServer)
+            var hasAuthority = NetworkManager.IsServer || (AllowOwnerToParent && IsOwner);
+
+            if (!hasAuthority)
             {
                 // Log exception if we are a client and not shutting down.
                 if (!NetworkManager.ShutdownInProgress)

com.unity.netcode.gameobjects/Runtime/Messaging/Messages/ParentSyncMessage.cs

@@ -106,19 +106,42 @@ public void Handle(ref NetworkContext context)
             networkObject.SetNetworkParenting(LatestParent, WorldPositionStays);
             networkObject.ApplyNetworkParenting(RemoveParent);
 
-            // We set all of the transform values after parenting as they are
-            // the values of the server-side post-parenting transform values
-            if (!WorldPositionStays)
+
+            // This check is primarily for client-server network topologies when the motion model is owner authoritative:
+            // When SyncOwnerTransformWhenParented is enabled, then always apply the transform values.
+            // When SyncOwnerTransformWhenParented is disabled, then only synchronize the transform on non-owner instances.
+            if (networkObject.SyncOwnerTransformWhenParented || (!networkObject.SyncOwnerTransformWhenParented && !networkObject.IsOwner))
             {
-                networkObject.transform.localPosition = Position;
-                networkObject.transform.localRotation = Rotation;
+                // We set all of the transform values after parenting as they are
+                // the values of the server-side post-parenting transform values
+                if (!WorldPositionStays)
+                {
+                    networkObject.transform.localPosition = Position;
+                    networkObject.transform.localRotation = Rotation;
+                }
+                else
+                {
+                    networkObject.transform.position = Position;
+                    networkObject.transform.rotation = Rotation;
+                }
             }
-            else
+            networkObject.transform.localScale = Scale;
+
+            // If client side parenting is enabled and this is the server instance, then notify the rest of the connected clients that parenting has taken place.
+            if (networkObject.AllowOwnerToParent && context.SenderId == networkObject.OwnerClientId && networkManager.IsServer)
             {
-                networkObject.transform.position = Position;
-                networkObject.transform.rotation = Rotation;
+                var size = 0;
+                var message = this;
+                foreach (var client in networkManager.ConnectedClients)
+                {
+                    if (client.Value.ClientId == networkObject.OwnerClientId || client.Value.ClientId == networkManager.LocalClientId || !networkObject.IsNetworkVisibleTo(client.Value.ClientId))
+                    {
+                        continue;
+                    }
+                    size = networkManager.ConnectionManager.SendMessage(ref message, NetworkDelivery.ReliableSequenced, client.Value.ClientId);
+                    networkManager.NetworkMetrics.TrackOwnershipChangeSent(client.Key, networkObject, size);
+                }
             }
-            networkObject.transform.localScale = Scale;
         }
     }
 }

com.unity.netcode.gameobjects/Tests/Runtime/NetworkTransform/NetworkTransformBase.cs

@@ -347,7 +347,6 @@ protected override void OnNewClientCreated(NetworkManager networkManager)
             base.OnNewClientCreated(networkManager);
         }
 
-
         /// <summary>
         /// Returns true when the server-host and all clients have
         /// instantiated the child object to be used in <see cref="NetworkTransformParentingLocalSpaceOffsetTests"/>
@@ -378,6 +377,26 @@ protected bool AllChildObjectInstancesAreSpawned()
             return true;
         }
 
+        /// <summary>
+        /// Conditional check that all child object instances also have a child
+        /// </summary>
+        /// <returns>true if they do and false if they do not</returns>
+        protected bool AllFirstLevelChildObjectInstancesHaveChild()
+        {
+            foreach (var instance in ChildObjectComponent.ClientInstances.Values)
+            {
+                if (instance.transform.parent == null)
+                {
+                    return false;
+                }
+            }
+            return true;
+        }
+
+        /// <summary>
+        /// Conditional check that all child instances have a child.
+        /// </summary>
+        /// <returns>true if they do and false if they do not</returns>
         protected bool AllChildObjectInstancesHaveChild()
         {
             foreach (var instance in ChildObjectComponent.ClientInstances.Values)
@@ -400,6 +419,41 @@ protected bool AllChildObjectInstancesHaveChild()
             return true;
         }
 
+        /// <summary>
+        /// Conditional check that all first level child objects have no parent.
+        /// </summary>
+        /// <returns>true if they do and false if they do not</returns>
+        protected bool AllFirstLevelChildObjectInstancesHaveNoParent()
+        {
+            foreach (var instance in ChildObjectComponent.ClientInstances.Values)
+            {
+                if (instance.transform.parent != null)
+                {
+                    return false;
+                }
+            }
+            return true;
+        }
+
+        /// <summary>
+        /// Conditional check that all sub-child objects have no parent.
+        /// </summary>
+        /// <returns>true if they do and false if they do not</returns>
+        protected bool AllSubChildObjectInstancesHaveNoParent()
+        {
+            if (ChildObjectComponent.HasSubChild)
+            {
+                foreach (var instance in ChildObjectComponent.ClientSubChildInstances.Values)
+                {
+                    if (instance.transform.parent != null)
+                    {
+                        return false;
+                    }
+                }
+            }
+            return true;
+        }
+
         /// <summary>
         /// A wait condition specific method that assures the local space coordinates
         /// are not impacted by NetworkTransform when parented.