How to get an Entiy to SharedComponentData Map

I'm looking for the SharedComponentData equivalent of ComponentDataFromEntity<MyComponent>()
or possibly a index derived from a group containing ComponentDataFromEntity to be used in SharedComponentData.

This is for an infrequent lookup.

 

EntityManager.GetSharedComponentData<T>(entity)

 

That's not the same thing.

I think the closest thing you can do is use the new Chunk approach, though this returns the index for shared components so you need to do a bit of a work around. Check out the new TransformSystem, I believe 1 section in there does it.

 

It's same as GetComponentData in simple way - get data by entity. Of course, this is different from the usual GetComponentData because the Shared component data is a different thing and have architectural differences, but on "top level" for users its same action: "System, give me please data for this entity"

 

He's not asking about GetComponentData though. He's asking about ComponentDataFromEntity.

ComponentDataFromEntity (what ComponentDataFromEntity returns) can be passed to Jobs to allow you to conditionally execute code if an entity has a specific component.

Code (CSharp):

1.         private struct Job : IJobParallelFor
2.         {
3.             [ReadOnly] public EntityArray Entities;
4.             [ReadOnly] public ComponentDataFromEntity<Initialized> IsInitialized;
5.  
6.             public void Execute(int index)
7.             {
8.                 if (IsInitialized.Exists(Entities[index]))
9.                 {
10.                     // Do somethibng
11.                 }
12.                 else
13.                 {
14.                     // Do something else
15.                 }
16.             }
17.         }

You can't do this with EntityManager.GetSharedComponentData

If you're not using it in a job, then sure, you can just use HasComponent<T> and GetSharedComponentData<T>

 

I know how it works and what limitations it has. We do not have enough context to understand whether he receives data in the job or not. Thus I described the simplest approach without jogs.

 

I posted a patch adding SharedComponentDataFromEntity here:

https://forum.unity.com/threads/missing-sharedcomponentdatafromentity.546130/#post-3603190

Was only a temporary workaround, I would rather use ArchetypeChunk now.