Getting Component Data from another Entity (Jobified Lambda in SystemBase)

I have entities that have a component that points to another entity by storing an Entity variable. I need to get component data from that associated entity to do work. An example of this is a camera system that follows the velocity of the object it's following (target stored as Entity, its PhysicsVelocity component data needed).

In ComponentSystem (main thread), one would use the Entity Manager, and just use EntityManager.GetComponentData to get the associated data.
In JobComponentSystem (multi threaded), one would use the GetComponentDataFromEntity container, and just plug the associated entity as an index to the collection (i.e. theData[theOtherEntity]).

How would one go about this in a Entities.ForEach(...).Schedule() or ScheduleParallel() (jobified) lambda in SystemBase?

 

You should be able top just also use GetComponentDataFromEntity inside your Entities.Foreach. Any issues trying to do so?

/edit: Check Enzis post below for correct answer

 

Actually, GetComponentDataFromEntity is used outside the ForEach and it gets captured in a display class in SystemBase.
You can also use GetComponent inside ForEach which gets translated into GetComponentDataFromEntity outside the ForEach when you look at the DOTS compiler.

 

@Enzi Do you know of a GetComponent-like shortcut for SystemBase ForEach but for DynamicBuffers?

 

are you looking for this GetBufferFromEntity<>

 

Ahh yes that's exactly right. Turns out Entities 0.11 doesn't have it, so I gotta update to 0.13

 

Small note - it will be GetBuffer<T>(Entity) if you looking for syntax sugar of SystemBase codegen.
GetBufferFromEntity lookup is similar to GetComponentFromEntity which should be captured outside of ForEach lambda. GetBuffer hides from you all boilerplate of GetBufferFromEntity under codegen. And yes it was added in 0.12.