How to Manage NativeArray(Allocator.Persistent) When Unloading Scenes/SubScene in Unity?

Unity Engine
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1

I’m making a game using ECS, and I have some Entities + ComponentData that contain NativeArray(Allocator.Persistent). I know I should Dispose these NativeArray when destroying the Entity. However, the issue arises when unloading Scenes/Subscenes, as these Entities may be destroyed along with the Scene, bypassing my cleanup process. My thoughts are: 1. Can Allocator.Domain solve this problem? 2. Manually clean up all Persistent-related items before unloading the scene. Any suggestions?

2

Something smells wrong here, how do you have native containers on entities that are linked to a subscene?

Are you baking native containers onto components because this isn’t allowed and will not work in builds.

3

this entity is a Baked Prefab, so will initiate in SubScene, However, the native container is not added through Baking, they are added by a System under certain conditions.

4

OK, so next question is. Why not just use a dynamic buffer to make everything a lot less problematic for yourself?

To answer your actual question though, the best way imo is just to react a subscene being closed with the following code - note i believe it will take internal access

    [UpdateInGroup(typeof(InitializationSystemGroup))]
    [UpdateBefore(typeof(SceneSystemGroup))]
    public partial struct RunBeforeSubSceneUnload : ISystem
    {
        /// <inheritdoc />
        [BurstCompile]
        public void OnUpdate(ref SystemState state)
        {
            foreach (var s in SystemAPI
                .Query<SceneSectionData>()
                .WithAll<SceneEntityReference, SceneSectionStreamingSystem.StreamingState>()
                .WithNone<RequestSceneLoaded, DisableSceneResolveAndLoad>())
            {
                var sceneSection = new SceneSection
                {
                    SceneGUID = s.SceneGUID,
                    Section = s.SubSectionIndex,
                };

                foreach (var d in SystemAPI.Query<YourComponent>().WithAll<SceneSection>().WithSharedComponentFilter(sceneSection))
                {
                    d.NativeArray.Dispose();
                }
            }
        }

Also put in an OnDestroy that’ll iterate all components and Dispose as well when shutting down world