Question Look up arbitrary data, question about doc code example

Just to clarify if I get this correctly or not. Trying to get back into the game...

Studying example code for ComponentLookup at https://docs.unity3d.com/Packages/com.unity.entities@1.0/manual/systems-looking-up-data.html , I wonder if the actual data from the lookup is somehow magically used, or if the job only uses the lookup to check that the linked entity still exist, and already has saved the target position in its "local entity" using another system.

If there isn't any magic I'm missing, in a real world example, wouldn't it be better to not keep the linked entity's posistion, and rather use the lookup to grab the position, replacing

Code (CSharp):

1. float3 targetPosition = entityPosition.Position;

with

Code (CSharp):

1. float 3 targetPosition = EntityPositions[targetEntity].Position;

The job from the page:

Code (CSharp):

1.     [BurstCompile]
2.     private partial struct MoveTowardsJob : IJobEntity
3.     {
4.  
5.         // Read-only data stored (potentially) in other chunks
6.         [ReadOnly]
7.         public ComponentLookup<LocalToWorld> EntityPositions;
8.  
9.         // Non-entity data
10.         public float deltaTime;
11.  
12.         public void Execute(ref LocalTransform transform, in Target target, in LocalToWorld entityPosition)
13.         {
14.             // Get the target Entity object
15.             Entity targetEntity = target.entity;
16.  
17.             // Check that the target still exists
18.             if (!EntityPositions.HasComponent(targetEntity))
19.                 return;
20.  
21.             // Update translation to move the chasing entity toward the target
22.             float3 targetPosition = entityPosition.Position;
23.             float3 chaserPosition = transform.Position;
24.  
25.             float3 displacement = targetPosition - chaserPosition;
26.             transform.Position = chaserPosition + displacement * deltaTime;
27.         }
28.     }
29.  

 

It's a typo in docs.

Code (CSharp):

1. float3 targetPosition = entityPosition.Position;

Should be

Code (CSharp):

1. float3 targetPosition = EntityPositions[targetEntity].Position;

 

Thank you, eizenhorn.

That's what puzzled me - it's not a simple typo, as they include component used (entityPosition) in the Execute parameters:

Code (CSharp):

1. public void Execute(ref LocalTransform transform, in Target target, in LocalToWorld entityPosition)
2.