access components in other entities inside the job system with ComponentDataArray

Unity Engine
,
1

I have a IJobProcessComponentDataWithEntity job and wish to access components in other entities inside the job system.

Many of the examples out there use ComponentDataArray, but they are now deprecated.

I understand the new way to do it is using GetComponentDataFromEntity (https://github.com/Unity-Technologies/EntityComponentSystemSamples/blob/master/Documentation~/component_data_from_entity.md), but I cannot figure out how to put it together.

Does anyone have a simple worked example of how the entire JobComponentSystem fits together with this?

Many thanks in advance )

2

I’m also trying: var value = GetComponentDataFromEntity<myComponent>(false)[anotherEntity];
I have the id of anotherEntity in the form of an int, but then do not know how to get the Entity in the job:
Entity anotherEntity = does anyone know the answer (anotherEntityId)

No idea if this is the right approach, or what other code I need to write. So really grateful for any help. Thanks )

3

You can’t just use an int for getting the Entity, you must have Index and Version (both ints).

4

Here is a simple example of accessing an attached entity’s parent

public class MySystem : JobComponentSystem {

  [BurstCompile]
  struct GatherParents : IJobProcessComponentData<Parent> {
    [ReadOnly]
    public ComponentDataFromEntity<LocalToWorld> LocalToWorldFromEntity;

    public void Execute(ref Parent parent) {
      var parentLocalToWorld = LocalToWorldFromEntity[parent.Value];
      // Do something with parent matrix
    }
  }

  protected override JobHandle OnUpdate(JobHandle inputDeps) {

    inputDeps = new GatherParents {
      LocalToWorldFromEntity = GetComponentDataFromEntity<LocalToWorld>(true)
    }.Schedule(this, inputDeps);

    return inputDeps;
  }
}

You can also have a job were you pass an entity to it but you must know that entity before hand not just guessig :slight_smile:

5

I’m not trying to access a parent. I’d just like to access a certain type of component in a job and refer to it by entity. It used to be that you could do this with ComponentDataArray. But, how do you do it now?

6

But you can do it with GetComponentFromEntity()[entity].
I don’t get the problem.
The above was an example.of usage in a job, Parent.Value is an entity.

1 Like
7

That makes sense, GilCat.
I realise now the other part of my problem is getting the entity.
What I want to do is have an entity with a component on it that refers to some other entity (like an edge in a graph),
That’s what I’m having trouble with in implementing. Any ideas?

8

I use exactly that. I have and Edge component that has reference to source entity and target entity and from there i can access whatever components i want both on source and target.

public struct EdgeComponent : IComponentData{
  public Entity Source;
  public Entity Target
}

Then use IJobProcessComponentData
Works great for me!

1 Like