fix: MirrorNetworking#3588 NetworkTransform OnTeleport doesn't call R…

…eset() anymore, causing NetworkTransformReliable's delta compression to get out of sync before

Assets/Mirror/Components/NetworkTransform/NetworkTransformBase.cs

@@ -313,13 +313,22 @@ void RpcReset()
         // common Teleport code for client->server and server->client
         protected virtual void OnTeleport(Vector3 destination)
         {
-            // reset any in-progress interpolation & buffers
-            Reset();
-
             // set the new position.
             // interpolation will automatically continue.
             target.position = destination;
 
+            // reset interpolation to immediately jump to the new position.
+            // do not call Reset() here, this would cause delta compression to
+            // get out of sync for NetworkTransformReliable because NTReliable's
+            // 'override Reset()' resets lastDe/SerializedPosition:
+            // https://github.com/MirrorNetworking/Mirror/issues/3588
+            // because client's next OnSerialize() will delta compress,
+            // but server's last delta will have been reset, causing offsets.
+            //
+            // instead, simply clear snapshots.
+            serverSnapshots.Clear();
+            clientSnapshots.Clear();
+
             // TODO
             // what if we still receive a snapshot from before the interpolation?
             // it could easily happen over unreliable.
@@ -329,14 +338,23 @@ protected virtual void OnTeleport(Vector3 destination)
         // common Teleport code for client->server and server->client
         protected virtual void OnTeleport(Vector3 destination, Quaternion rotation)
         {
-            // reset any in-progress interpolation & buffers
-            Reset();
-
             // set the new position.
             // interpolation will automatically continue.
             target.position = destination;
             target.rotation = rotation;
 
+            // reset interpolation to immediately jump to the new position.
+            // do not call Reset() here, this would cause delta compression to
+            // get out of sync for NetworkTransformReliable because NTReliable's
+            // 'override Reset()' resets lastDe/SerializedPosition:
+            // https://github.com/MirrorNetworking/Mirror/issues/3588
+            // because client's next OnSerialize() will delta compress,
+            // but server's last delta will have been reset, causing offsets.
+            //
+            // instead, simply clear snapshots.
+            serverSnapshots.Clear();
+            clientSnapshots.Clear();
+
             // TODO
             // what if we still receive a snapshot from before the interpolation?
             // it could easily happen over unreliable.

Assets/Mirror/Components/NetworkTransform/NetworkTransformReliable.cs

@@ -405,6 +405,9 @@ static void RewriteHistory(
             );
         }
 
+        // reset state for next session.
+        // do not ever call this during a session (i.e. after teleport).
+        // calling this will break delta compression.
         public override void Reset()
         {
             base.Reset();