[Solved] LocalToWorld seems to be updated every frame no matter what

I've tried this:

Code (CSharp):

1. public class ChangeDetectionSystem : JobComponentSystem
2.     {
3.         protected override JobHandle OnUpdate(JobHandle inputDeps)
4.         {
5.             return this.Entities
6.                 .WithChangeFilter<LocalToParent>()
7.                 .ForEach(
8.                     (in Entity entity, in LocalToParent ltp) =>
9.                     {
10.                         UnityEngine.Debug.Log($"LocalToParent changed in {entity}");
11.                     }
12.                 )
13.                 .Schedule(inputDeps);
14.         }
15.     }

And for a child entity with the Translation component it detects change in LocalToParent every frame. I've looked through the source of TRSToLocalToParentSystem and it seems to me that it doesn't check DidChange. Interesting that TRSToLocalToWorldSystem and LocalToParentSystem both perform change checks. So my question is: did I miss something? Or is it by design? Or some considerations that I'm not aware of?

 

Ok, I've tried a subscene with just one empty game object. When converted it produces just one entity with LocalToWorld and Translation. In this case LocalToWorld gets updated just two first frames then I think change detection comes into play and .WithChangeFilter<LocalToWorld>() stops picking up the entity. This means that TRSToLocalToWorldSystem definitely respects Translation (un)changed status.

 

So does anybody know if it is working now as intended? I.e. should the LocalToParentSystem actually perform matrix calculation every frame, even when there's no change? I think it would be beneficial if this aspect was optimized. Not only would it reduce the amount of unnecessary calculations, but it would also allow other systems to only work when the positioning of an entity in the world has actually changed.

 

If anyone is interested or not, I have checked Entities 0.7.0 and can confirm that this issue has been resolved. I.e. now LocalToWorld on children is NOT being updated every frame when there is no change. Thank you Unity Entities team.