feature: allow NetworkBehaviour components in children. solves #2276 (#3486)

* feature: allow child NetworkBehaviour components in children

* Tanks demo: move Turret NetworkTransform to child

* NT TODO

* RequireInParents NI

* NetworkAnimatore allow in children

* call base onvalidate

* Add OnValidate to Script Template

* fix for pre-2020.3 Unity

* MirrorTest: CreateNetworked with NetworkBehaviour in children

* Tests: child networkbehaviours

---------

Co-authored-by: MrGadget1024 <9826063+MrGadget1024@users.noreply.github.com>

Author: 2 people

Assets/Mirror/Components/Experimental/NetworkLerpRigidbody.cs

@@ -33,8 +33,9 @@ public class NetworkLerpRigidbody : NetworkBehaviour
 
         bool ClientWithAuthority => clientAuthority && isOwned;
 
-        void OnValidate()
+        protected override void OnValidate()
         {
+            base.OnValidate();
             if (target == null)
                 target = GetComponent<Rigidbody>();
         }

Assets/Mirror/Components/Experimental/NetworkRigidbody.cs

@@ -37,8 +37,9 @@ public class NetworkRigidbody : NetworkBehaviour
         /// </summary>
         readonly ClientSyncState previousValue = new ClientSyncState();
 
-        void OnValidate()
+        protected override void OnValidate()
         {
+            base.OnValidate();
             if (target == null)
                 target = GetComponent<Rigidbody>();
         }

Assets/Mirror/Components/Experimental/NetworkRigidbody2D.cs

@@ -37,8 +37,9 @@ public class NetworkRigidbody2D : NetworkBehaviour
         /// </summary>
         readonly ClientSyncState previousValue = new ClientSyncState();
 
-        void OnValidate()
+        protected override void OnValidate()
         {
+            base.OnValidate();
             if (target == null)
                 target = GetComponent<Rigidbody2D>();
         }

Assets/Mirror/Components/NetworkAnimator.cs

@@ -13,8 +13,8 @@ namespace Mirror
     /// <para>If the object has authority on the server, then it should be animated on the server and state information will be sent to all clients. This is common for objects not related to a specific client, such as an enemy unit.</para>
     /// <para>The NetworkAnimator synchronizes all animation parameters of the selected Animator. It does not automatically synchronize triggers. The function SetTrigger can by used by an object with authority to fire an animation trigger on other clients.</para>
     /// </remarks>
+    // [RequireComponent(typeof(NetworkIdentity))] disabled to allow child NetworkBehaviours
     [AddComponentMenu("Network/Network Animator")]
-    [RequireComponent(typeof(NetworkIdentity))]
     [HelpURL("https://mirror-networking.gitbook.io/docs/components/network-animator")]
     public class NetworkAnimator : NetworkBehaviour
     {

Assets/Mirror/Components/NetworkTransformBase.cs

@@ -25,6 +25,7 @@ namespace Mirror
     public abstract class NetworkTransformBase : NetworkBehaviour
     {
         // target transform to sync. can be on a child.
+        // TODO this field is kind of unnecessary since we now support child NetworkBehaviours
         [Header("Target")]
         [Tooltip("The Transform component to sync. May be on on this GameObject, or on a child.")]
         public Transform target;
@@ -67,17 +68,17 @@ public abstract class NetworkTransformBase : NetworkBehaviour
         public bool timelineOffset = false;
 
         // Ninja's Notes on offset & mulitplier:
-        // 
+        //
         // In a no multiplier scenario:
         // 1. Snapshots are sent every frame (frame being 1 NM send interval).
         // 2. Time Interpolation is set to be 'behind' by 2 frames times.
         // In theory where everything works, we probably have around 2 snapshots before we need to interpolate snapshots. From NT perspective, we should always have around 2 snapshots ready, so no stutter.
-        // 
+        //
         // In a multiplier scenario:
         // 1. Snapshots are sent every 10 frames.
         // 2. Time Interpolation remains 'behind by 2 frames'.
-        // When everything works, we are receiving NT snapshots every 10 frames, but start interpolating after 2. 
-        // Even if I assume we had 2 snapshots to begin with to start interpolating (which we don't), by the time we reach 13th frame, we are out of snapshots, and have to wait 7 frames for next snapshot to come. This is the reason why we absolutely need the timestamp adjustment. We are starting way too early to interpolate. 
+        // When everything works, we are receiving NT snapshots every 10 frames, but start interpolating after 2.
+        // Even if I assume we had 2 snapshots to begin with to start interpolating (which we don't), by the time we reach 13th frame, we are out of snapshots, and have to wait 7 frames for next snapshot to come. This is the reason why we absolutely need the timestamp adjustment. We are starting way too early to interpolate.
         //
         protected double timeStampAdjustment => NetworkServer.sendInterval * (sendIntervalMultiplier - 1);
         protected double offset => timelineOffset ? NetworkServer.sendInterval * sendIntervalMultiplier : 0;
@@ -92,8 +93,10 @@ public abstract class NetworkTransformBase : NetworkBehaviour
         // make sure to call this when inheriting too!
         protected virtual void Awake() { }
 
-        protected virtual void OnValidate()
+        protected override void OnValidate()
         {
+            base.OnValidate();
+
             // set target to self if none yet
             if (target == null) target = transform;
 

Assets/Mirror/Components/RemoteStatistics.cs

@@ -133,8 +133,9 @@ void LoadPassword()
             }
         }
 
-        void OnValidate()
+        protected override void OnValidate()
         {
+            base.OnValidate();
             syncMode = SyncMode.Owner;
         }
 

Assets/Mirror/Core/NetworkBehaviour.cs

@@ -19,8 +19,8 @@ public enum SyncMode { Observers, Owner }
     public enum SyncDirection { ServerToClient, ClientToServer }
 
     /// <summary>Base class for networked components.</summary>
+    // [RequireComponent(typeof(NetworkIdentity))] disabled to allow child NetworkBehaviours
     [AddComponentMenu("")]
-    [RequireComponent(typeof(NetworkIdentity))]
     [HelpURL("https://mirror-networking.gitbook.io/docs/guides/networkbehaviour")]
     public abstract class NetworkBehaviour : MonoBehaviour
     {
@@ -293,6 +293,27 @@ protected void InitSyncObject(SyncObject syncObject)
             };
         }
 
+        protected virtual void OnValidate()
+        {
+            // we now allow child NetworkBehaviours.
+            // we can not [RequireComponent(typeof(NetworkIdentity))] anymore.
+            // instead, we need to ensure a NetworkIdentity is somewhere in the
+            // parents.
+            // only run this in Editor. don't add more runtime overhead.
+
+#if UNITY_EDITOR
+            if (GetComponent<NetworkIdentity>() == null &&
+#if UNITY_2020_3_OR_NEWER
+                GetComponentInParent<NetworkIdentity>(true) == null)
+#else
+                GetComponentInParent<NetworkIdentity>() == null)
+#endif
+            {
+                Debug.LogError($"{GetType()} on {name} requires a NetworkIdentity. Please add a NetworkIdentity component to {name} or it's parents.");
+            }
+#endif
+        }
+
         // pass full function name to avoid ClassA.Func <-> ClassB.Func collisions
         protected void SendCommandInternal(string functionFullName, int functionHashCode, NetworkWriter writer, int channelId, bool requiresAuthority = true)
         {

Assets/Mirror/Core/NetworkClient.cs

@@ -534,6 +534,9 @@ static void RegisterPrefabIdentity(NetworkIdentity prefab)
                 return;
             }
 
+            // disallow child NetworkIdentities.
+            // TODO likely not necessary anymore due to the new check in
+            // NetworkIdentity.OnValidate.
             NetworkIdentity[] identities = prefab.GetComponentsInChildren<NetworkIdentity>();
             if (identities.Length > 1)
             {

Assets/Mirror/Core/NetworkIdentity.cs

@@ -292,9 +292,12 @@ internal static void ResetServerStatics()
         // BUT internal so tests can add them after creating the NetworkIdentity
         internal void InitializeNetworkBehaviours()
         {
-            // Get all NetworkBehaviours
-            // (never null. GetComponents returns [] if none found)
-            NetworkBehaviours = GetComponents<NetworkBehaviour>();
+            // Get all NetworkBehaviour components, including children.
+            // Some users need NetworkTransform on child bones, etc.
+            // => Deterministic: https://forum.unity.com/threads/getcomponentsinchildren.4582/#post-33983
+            // => Never null. GetComponents returns [] if none found.
+            // => Include inactive. We need all child components.
+            NetworkBehaviours = GetComponentsInChildren<NetworkBehaviour>(true);
             ValidateComponents();
 
             // initialize each one
@@ -347,11 +350,29 @@ void OnValidate()
             hasSpawned = false;
 
 #if UNITY_EDITOR
+            DisallowChildNetworkIdentities();
             SetupIDs();
 #endif
         }
 
 #if UNITY_EDITOR
+        // child NetworkIdentities are not supported.
+        // Disallow them and show an error for the user to fix.
+        // This needs to work for Prefabs & Scene objects, so the previous check
+        // in NetworkClient.RegisterPrefab is not enough.
+        void DisallowChildNetworkIdentities()
+        {
+#if UNITY_2020_3_OR_NEWER
+            NetworkIdentity[] identities = GetComponentsInChildren<NetworkIdentity>(true);
+#else
+            NetworkIdentity[] identities = GetComponentsInChildren<NetworkIdentity>();
+#endif
+            if (identities.Length > 1)
+            {
+                Debug.LogError($"'{name}' has {identities.Length} NetworkIdentity components. There should only be one NetworkIdentity, and it must be on the root object.");
+            }
+        }
+
         void AssignAssetID(string path)
         {
             // only set if not empty. fixes https://github.com/vis2k/Mirror/issues/2765

Assets/Mirror/Examples/AdditiveLevels/Scripts/PlayerController.cs

@@ -54,8 +54,10 @@ public enum GroundState : byte { Jumping, Falling, Grounded }
         public Vector3Int velocity;
         public Vector3 direction;
 
-        void OnValidate()
+        protected override void OnValidate()
         {
+            base.OnValidate();
+
             if (characterController == null)
                 characterController = GetComponent<CharacterController>();