Access two transforms in a Job

Unity Engine
,
1

I have a very simple job that is trying to keep objects facing the camera:

struct KeepFacingCameraJob : IJobParallelFor
{
[ReadOnly]
public TransformAccessArray cameras;
[ReadOnly]
public TransformAccessArray objects;

public void Execute(int i)
{
objects = cameras*.rotation;*
}
}
This produces an error about unsafe pointers. I could use IJobParallelForTransform but then I can only access a single transform. How can I access multiple transforms in a job?

2

From what I know the TransformAccessArray is part of the hybrid functionality that’s been added. In this case it’ll provide access to the Transform object, NOT a struct type that can be safely accessed from a job. Also note that you’ve marked the TransformAccessArray you’re transforming as ReadOnly which is an optimization attribute used to determine if a job can be run concurrently with another because it’s only accessing data and not changing it, thus not able to cause race conditions.

3

Thanks. I can work around this by using the IJobParallelForTransform to modify the target object’s transform and storing the camera rotations into an array I can index in the Job instead of accessing the camera’s transform itself. It’s a bit clumsy of course.

But I guess the question is, how can I make a job that can use one transform to modify another transform. Practical example - I have a bunch of child objects which are dependant on their parent’s position/rotation/movement in some non-linear way.

4

I’ve looked through some of the Entities code and came across the TransformParentComponent you could use to parent the Transforms to the camera objects. The built-in TransformSystem takes care of matching rotation to that of the parent if the components are matched correctly.

5

I have that exact case (almost), child objects that need to rotate based on where the parent is. I just use separate jobs for each where the child job depends on the parent job.