fix: NetworkSceneManager does not synchronize despawned in-scene placed NetworkObjects [MTT-2924]

com.unity.netcode.gameobjects/CHANGELOG.md

@@ -18,14 +18,15 @@ Additional documentation and release notes are available at [Multiplayer Documen
 ### Changed
 
 - `unmanaged` structs are no longer universally accepted as RPC parameters because some structs (i.e., structs with pointers in them, such as `NativeList<T>`) can't be supported by the default memcpy struct serializer. Structs that are intended to be serialized across the network must add `INetworkSerializeByMemcpy` to the interface list (i.e., `struct Foo : INetworkSerializeByMemcpy`). This interface is empty and just serves to mark the struct as compatible with memcpy serialization. For external structs you can't edit, you can pass them to RPCs by wrapping them in `ForceNetworkSerializeByMemcpy<T>`. (#1901)
+- Changed requirement to register in-scene placed NetworkObjects with `NetworkManager` in order to respawn them.  In-scene placed NetworkObjects are now automatically tracked during runtime and no longer need to be registered as a NetworkPrefab.  (#1898)
 
 ### Removed
 - Removed `SIPTransport` (#1870)
 
 - Removed `ClientNetworkTransform` from the package samples and moved to Boss Room's Utilities package which can be found [here](https://github.com/Unity-Technologies/com.unity.multiplayer.samples.coop/blob/main/Packages/com.unity.multiplayer.samples.coop/Utilities/Net/ClientAuthority/ClientNetworkTransform.cs).
 
 ### Fixed
-
+- Fixed issue where `NetworkSceneManager` did not synchronize despawned in-scene placed NetworkObjects. (#1898)
 - Fixed `NetworkTransform` generating false positive rotation delta checks when rolling over between 0 and 360 degrees. (#1890)
 - Fixed client throwing an exception if it has messages in the outbound queue when processing the `NetworkEvent.Disconnect` event and is using UTP. (#1884)
 - Fixed issue during client synchronization if 'ValidateSceneBeforeLoading' returned false it would halt the client synchronization process resulting in a client that was approved but not synchronized or fully connected with the server. (#1883)
@@ -36,6 +37,7 @@ Additional documentation and release notes are available at [Multiplayer Documen
 ## [1.0.0-pre.7] - 2022-04-06
 
 ### Added
+
 - Added editor only check prior to entering into play mode if the currently open and active scene is in the build list and if not displays a dialog box asking the user if they would like to automatically add it prior to entering into play mode. (#1828)
 - Added `UnityTransport` implementation and `com.unity.transport` package dependency (#1823)
 - Added `NetworkVariableWritePermission` to `NetworkVariableBase` and implemented `Owner` client writable netvars. (#1762)

com.unity.netcode.gameobjects/Editor/NetworkBehaviourEditor.cs

@@ -218,6 +218,11 @@ public override void OnInspectorGUI()
         /// </summary>
         private void OnEnable()
         {
+            // This can be null and throw an exception when running test runner in the editor
+            if (target == null)
+            {
+                return;
+            }
             // When we first add a NetworkBehaviour this editor will be enabled
             // so we go ahead and check for an already existing NetworkObject here
             CheckForNetworkObject((target as NetworkBehaviour).gameObject);

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

@@ -1838,7 +1838,7 @@ internal void HandleApproval(ulong ownerClientId, bool createPlayerObject, uint?
 
                 if (createPlayerObject)
                 {
-                    var networkObject = SpawnManager.CreateLocalNetworkObject(false, playerPrefabHash ?? NetworkConfig.PlayerPrefab.GetComponent<NetworkObject>().GlobalObjectIdHash, ownerClientId, null, position, rotation);
+                    var networkObject = SpawnManager.CreateLocalNetworkObject(false, playerPrefabHash ?? NetworkConfig.PlayerPrefab.GetComponent<NetworkObject>().GlobalObjectIdHash, ownerClientId, null, null, position, rotation);
                     SpawnManager.SpawnNetworkObjectLocally(networkObject, SpawnManager.GetNetworkObjectId(), false, true, ownerClientId, false);
 
                     ConnectedClients[ownerClientId].PlayerObject = networkObject;

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

@@ -151,6 +151,7 @@ internal string GetNameForMetrics()
 #endif
         }
 
+        private readonly HashSet<ulong> m_EmptyULongHashSet = new HashSet<ulong>();
         /// <summary>
         /// Returns Observers enumerator
         /// </summary>
@@ -159,7 +160,7 @@ public HashSet<ulong>.Enumerator GetObservers()
         {
             if (!IsSpawned)
             {
-                throw new SpawnStateException("Object is not spawned");
+                return m_EmptyULongHashSet.GetEnumerator();
             }
 
             return Observers.GetEnumerator();
@@ -174,9 +175,8 @@ public bool IsNetworkVisibleTo(ulong clientId)
         {
             if (!IsSpawned)
             {
-                throw new SpawnStateException("Object is not spawned");
+                return false;
             }
-
             return Observers.Contains(clientId);
         }
 
@@ -372,7 +372,7 @@ private void SpawnInternal(bool destroyWithScene, ulong ownerClientId, bool play
                 throw new NotServerException($"Only server can spawn {nameof(NetworkObject)}s");
             }
 
-            NetworkManager.SpawnManager.SpawnNetworkObjectLocally(this, NetworkManager.SpawnManager.GetNetworkObjectId(), false, playerObject, ownerClientId, destroyWithScene);
+            NetworkManager.SpawnManager.SpawnNetworkObjectLocally(this, NetworkManager.SpawnManager.GetNetworkObjectId(), IsSceneObject.HasValue && IsSceneObject.Value, playerObject, ownerClientId, destroyWithScene);
 
             for (int i = 0; i < NetworkManager.ConnectedClientsList.Count; i++)
             {
@@ -865,16 +865,17 @@ public struct TransformData : INetworkSerializeByMemcpy
             public NetworkObject OwnerObject;
             public ulong TargetClientId;
 
+            public int NetworkSceneHandle;
+
             public unsafe void Serialize(FastBufferWriter writer)
             {
-                if (!writer.TryBeginWrite(
-                    sizeof(HeaderData) +
-                    (Header.HasParent ? FastBufferWriter.GetWriteSize(ParentObjectId) : 0) +
-                    (Header.HasTransform ? FastBufferWriter.GetWriteSize(Transform) : 0) +
-                    (Header.IsReparented
-                        ? FastBufferWriter.GetWriteSize(IsLatestParentSet) +
-                          (IsLatestParentSet ? FastBufferWriter.GetWriteSize<ulong>() : 0)
-                        : 0)))
+                var writeSize = sizeof(HeaderData);
+                writeSize += Header.HasParent ? FastBufferWriter.GetWriteSize(ParentObjectId) : 0;
+                writeSize += Header.HasTransform ? FastBufferWriter.GetWriteSize(Transform) : 0;
+                writeSize += Header.IsReparented ? FastBufferWriter.GetWriteSize(IsLatestParentSet) + (IsLatestParentSet ? FastBufferWriter.GetWriteSize<ulong>() : 0) : 0;
+                writeSize += Header.IsSceneObject ? FastBufferWriter.GetWriteSize<int>() : 0;
+
+                if (!writer.TryBeginWrite(writeSize))
                 {
                     throw new OverflowException("Could not serialize SceneObject: Out of buffer space.");
                 }
@@ -900,6 +901,16 @@ public unsafe void Serialize(FastBufferWriter writer)
                     }
                 }
 
+                // In-Scene NetworkObjects are uniquely identified NetworkPrefabs defined by their
+                // NetworkSceneHandle and GlobalObjectIdHash. Since each loaded scene has a unique
+                // handle, it provides us with a unique and persistent "scene prefab asset" instance.
+                // This is only set on in-scene placed NetworkObjects to reduce the over-all packet
+                // sizes for dynamically spawned NetworkObjects.
+                if (Header.IsSceneObject)
+                {
+                    writer.WriteValue(OwnerObject.gameObject.scene.handle);
+                }
+
                 OwnerObject.WriteNetworkVariableData(writer, TargetClientId);
             }
 
@@ -910,10 +921,12 @@ public unsafe void Deserialize(FastBufferReader reader)
                     throw new OverflowException("Could not deserialize SceneObject: Out of buffer space.");
                 }
                 reader.ReadValue(out Header);
-                if (!reader.TryBeginRead(
-                    (Header.HasParent ? FastBufferWriter.GetWriteSize(ParentObjectId) : 0) +
-                    (Header.HasTransform ? FastBufferWriter.GetWriteSize(Transform) : 0) +
-                    (Header.IsReparented ? FastBufferWriter.GetWriteSize(IsLatestParentSet) : 0)))
+                var readSize = Header.HasParent ? FastBufferWriter.GetWriteSize(ParentObjectId) : 0;
+                readSize += Header.HasTransform ? FastBufferWriter.GetWriteSize(Transform) : 0;
+                readSize += Header.IsReparented ? FastBufferWriter.GetWriteSize(IsLatestParentSet) + (IsLatestParentSet ? FastBufferWriter.GetWriteSize<ulong>() : 0) : 0;
+                readSize += Header.IsSceneObject ? FastBufferWriter.GetWriteSize<int>() : 0;
+
+                if (!reader.TryBeginRead(readSize))
                 {
                     throw new OverflowException("Could not deserialize SceneObject: Out of buffer space.");
                 }
@@ -937,6 +950,16 @@ public unsafe void Deserialize(FastBufferReader reader)
                         LatestParent = latestParent;
                     }
                 }
+
+                // In-Scene NetworkObjects are uniquely identified NetworkPrefabs defined by their
+                // NetworkSceneHandle and GlobalObjectIdHash. Since each loaded scene has a unique
+                // handle, it provides us with a unique and persistent "scene prefab asset" instance.
+                // Client-side NetworkSceneManagers use this to locate their local instance of the
+                // NetworkObject instance.
+                if (Header.IsSceneObject)
+                {
+                    reader.ReadValue(out NetworkSceneHandle);
+                }
             }
         }
 
@@ -1006,6 +1029,7 @@ internal static NetworkObject AddSceneObject(in SceneObject sceneObject, FastBuf
             Vector3? position = null;
             Quaternion? rotation = null;
             ulong? parentNetworkId = null;
+            int? networkSceneHandle = null;
 
             if (sceneObject.Header.HasTransform)
             {
@@ -1018,10 +1042,15 @@ internal static NetworkObject AddSceneObject(in SceneObject sceneObject, FastBuf
                 parentNetworkId = sceneObject.ParentObjectId;
             }
 
+            if (sceneObject.Header.IsSceneObject)
+            {
+                networkSceneHandle = sceneObject.NetworkSceneHandle;
+            }
+
             //Attempt to create a local NetworkObject
             var networkObject = networkManager.SpawnManager.CreateLocalNetworkObject(
                 sceneObject.Header.IsSceneObject, sceneObject.Header.Hash,
-                sceneObject.Header.OwnerClientId, parentNetworkId, position, rotation, sceneObject.Header.IsReparented);
+                sceneObject.Header.OwnerClientId, parentNetworkId, networkSceneHandle, position, rotation, sceneObject.Header.IsReparented);
 
             networkObject?.SetNetworkParenting(sceneObject.Header.IsReparented, sceneObject.LatestParent);
 

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

@@ -19,7 +19,7 @@ public bool Deserialize(FastBufferReader reader, ref NetworkContext context)
             }
 
             ObjectInfo.Deserialize(reader);
-            if (!networkManager.NetworkConfig.ForceSamePrefabs && !networkManager.SpawnManager.HasPrefab(ObjectInfo.Header.IsSceneObject, ObjectInfo.Header.Hash))
+            if (!networkManager.NetworkConfig.ForceSamePrefabs && !networkManager.SpawnManager.HasPrefab(ObjectInfo))
             {
                 networkManager.DeferredMessageManager.DeferMessage(IDeferredMessageManager.TriggerType.OnAddPrefab, ObjectInfo.Header.Hash, reader, ref context);
                 return false;

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

@@ -3,6 +3,7 @@ namespace Unity.Netcode
     internal struct DestroyObjectMessage : INetworkMessage, INetworkSerializeByMemcpy
     {
         public ulong NetworkObjectId;
+        public bool DestroyGameObject;
 
         public void Serialize(FastBufferWriter writer)
         {
@@ -37,7 +38,7 @@ public void Handle(ref NetworkContext context)
             }
 
             networkManager.NetworkMetrics.TrackObjectDestroyReceived(context.SenderId, networkObject, context.MessageSize);
-            networkManager.SpawnManager.OnDespawnObject(networkObject, true);
+            networkManager.SpawnManager.OnDespawnObject(networkObject, DestroyGameObject);
         }
     }
 }

com.unity.netcode.gameobjects/Runtime/SceneManagement/ISceneManagerHandler.cs

@@ -15,8 +15,14 @@ struct SceneEventAction
         {
             internal uint SceneEventId;
             internal Action<uint> EventAction;
+            /// <summary>
+            /// Used server-side for integration testing in order to
+            /// invoke the SceneEventProgress once done loading
+            /// </summary>
+            internal Action Completed;
             internal void Invoke()
             {
+                Completed?.Invoke();
                 EventAction.Invoke(SceneEventId);
             }
         }