How to deserialize a world with SharedComponents?

The old examples no longer work, there are now additional parameters:
SerializeWorld(EntityManager entityManager, BinaryWriter writer, out int[] sharedComponentsToSerialize)
DeserializeWorld(ExclusiveEntityTransaction manager, BinaryReader reader, int numSharedComponents)

I have a simple scene with 2 MeshInstanceRenderers which are SharedComponents, my code is:

Code (CSharp):

1. private void SaveWorld()
2. {
3.     EntityManager entityManager = World.Active.GetOrCreateManager<EntityManager>();
4.  
5.     using (Unity.Entities.Serialization.BinaryWriter writer = new StreamBinaryWriter(savedWorldFilename))
6.     {
7.         int[] sharedComponents;
8.         SerializeUtility.SerializeWorld(entityManager, writer, out sharedComponents);
9.     }
10. }
11.  
12. private void LoadWorld()
13. {
14.     EntityManager entityManager = World.Active.GetOrCreateManager<EntityManager>();
15.  
16.     using (Unity.Entities.Serialization.BinaryReader reader = new StreamBinaryReader(savedWorldFilename))
17.     {
18.         using (World tempWorld = new World("loading"))
19.         {
20.             EntityManager e2 = tempWorld.GetOrCreateManager<EntityManager>();
21.  
22.             SerializeUtility.DeserializeWorld(e2.BeginExclusiveEntityTransaction(), reader, 2);
23.             e2.EndExclusiveEntityTransaction();
24.  
25.             entityManager.MoveEntitiesFrom(e2);
26.         }
27.     }
28. }
29.  

From SerializeWorld I get out int[] sharedComponents = {2, 1}. Do I need to do some additional steps here?

No matter what I pass to DeserializeWorld as parameter numSharedComponents, I always get an error (I tried 0, 1, 2).

NullReferenceException: Object reference not set to an instance of an object
Unity.Entities.EntityDataManager.TryRemoveEntityId (Unity.Entities.Entity* entities, System.Int32 count, Unity.Entities.ArchetypeManager archetypeManager, Unity.Entities.SharedComponentDataManager sharedComponentDataManager, Unity.Entities.EntityGroupManager groupManager, Unity.Entities.ComponentTypeInArchetype* componentTypeInArchetypeArray) (at C:/Users/Michal/AppData/Local/Unity/cache/packages/staging-packages.unity.com/com.unity.entities@0.0.12-preview.19/Unity.Entities/EntityDataManager.cs:896)
Unity.Entities.EntityManager.DestroyEntityInternal (Unity.Entities.Entity* entities, System.Int32 count) (at C:/Users/Michal/AppData/Local/Unity/cache/packages/staging-packages.unity.com/com.unity.entities@0.0.12-preview.19/Unity.Entities/EntityManager.cs:341)
Unity.Entities.EntityManager.DestroyEntity (Unity.Collections.NativeArray`1[T] entities) (at C:/Users/Michal/AppData/Local/Unity/cache/packages/staging-packages.unity.com/com.unity.entities@0.0.12-preview.19/Unity.Entities/EntityManager.cs:324)
Unity.Entities.EntityManager.OnDestroyManager () (at C:/Users/Michal/AppData/Local/Unity/cache/packages/staging-packages.unity.com/com.unity.entities@0.0.12-preview.19/Unity.Entities/EntityManager.cs:204)
Unity.Entities.ScriptBehaviourManager.DestroyInstance () (at C:/Users/Michal/AppData/Local/Unity/cache/packages/staging-packages.unity.com/com.unity.entities@0.0.12-preview.19/Unity.Entities/ScriptBehaviourManager.cs:41)
Unity.Entities.World.Dispose () (at C:/Users/Michal/AppData/Local/Unity/cache/packages/staging-packages.unity.com/com.unity.entities@0.0.12-preview.19/Unity.Entities/Injection/World.cs:73)
UnityEngine.Debug:LogException(Exception)
Unity.Debug:LogException(Exception) (at C:/Users/Michal/AppData/Local/Unity/cache/packages/staging-packages.unity.com/com.unity.entities@0.0.12-preview.19/Unity.Entities/Stubs/Unity/Debug.cs:25)
Unity.Entities.Worldispose() (at C:/Users/Michal/AppData/Local/Unity/cache/packages/staging-packages.unity.com/com.unity.entities@0.0.12-preview.19/Unity.Entities/Injection/World.cs:77)
BootTime:LoadWorld() (at Assets/Code/BootTime/BootTime.cs:71)
BootTime:Update() (at Assets/Code/BootTime/BootTime.cs:50)

IndexOutOfRangeException: Index 1 is out of range in NativeList of '1' Length.
Unity.Collections.NativeListImpl`3[T,TMemManager,TSentinel].get_Item (System.Int32 index) (at C:/Users/Michal/AppData/Local/Unity/cache/packages/staging-packages.unity.com/com.unity.collections@0.0.9-preview.9/Unity.Collections/NativeListImpl.cs:57)
Unity.Collections.NativeList`1[T].get_Item (System.Int32 index) (at C:/Users/Michal/AppData/Local/Unity/cache/packages/staging-packages.unity.com/com.unity.collections@0.0.9-preview.9/Unity.Collections/NativeList.cs:49)
Unity.Entities.SharedComponentDataManager.AddReference (System.Int32 index) (at C:/Users/Michal/AppData/Local/Unity/cache/packages/staging-packages.unity.com/com.unity.entities@0.0.12-preview.19/Unity.Entities/SharedComponentManager.cs:215)
Unity.Entities.ArchetypeManager.AddExistingChunk (Unity.Entities.Chunk* chunk) (at C:/Users/Michal/AppData/Local/Unity/cache/packages/staging-packages.unity.com/com.unity.entities@0.0.12-preview.19/Unity.Entities/ArchetypeManager.cs:685)
Unity.Entities.ExclusiveEntityTransaction.AddExistingChunk (Unity.Entities.Chunk* chunk) (at C:/Users/Michal/AppData/Local/Unity/cache/packages/staging-packages.unity.com/com.unity.entities@0.0.12-preview.19/Unity.Entities/ExclusiveEntityTransaction.cs:276)
Unity.Entities.Serialization.SerializeUtility.DeserializeWorld (Unity.Entities.ExclusiveEntityTransaction manager, Unity.Entities.Serialization.BinaryReader reader, System.Int32 numSharedComponents) (at C:/Users/Michal/AppData/Local/Unity/cache/packages/staging-packages.unity.com/com.unity.entities@0.0.12-preview.19/Unity.Entities/SerializeUtility.cs:89)
BootTime.LoadWorld () (at Assets/Code/BootTime/BootTime.cs:75)
BootTime.Update () (at Assets/Code/BootTime/BootTime.cs:50)

 

OK, so I can use SerializeUtilityHybrid.Serialize / Deserialize as in:
FPSSample/Packages/com.unity.entities/Unity.Entities.Hybrid.Tests/Runtime/SharedComponentSerializeTests.cs

where sharedComponents stays in memory between Serialize and Deserialize.

But how can I serialize and deserialize sharedComponents? What do you mean in a prefab? Isn't it available only in the editor, not at runtime?

Thanks in advance.

 

Thank you, that approach worked for me.

My use case is that I am trying to implement the usual savegame functionality (game save and load). I guess that's possible as long as the SharedComponents (MeshInstanceRenderers) are not changing during runtime and I can write them once into a prefab when the game is running in Unity Editor.

 

I would be nice if during Serialize with only selective Entity (with a list of typeof<IComponent> as input). Instead of Serialize the whole World of junks and then late on running so many issues to Deserialize...