Get System Update Order

I am writing a deterministic simulation where there is a Tick() method on each system which gets executed 10 times per second irrespective of frame-rate. This Tick() method will be present on all systems and must called on them in the same order as the order in which OnUpdate() is called. Is there a way I can get the list of systems in the order Update() will be called on them taking into account dependencies, UpdateBefore, UpdateAfter etc? Or if there is a better way to implement this, I'd love to hear that as well.

 

Would it not be easier to use existing update sequence by limiting frame rate and using FixedUupdate()?

But I'm sure there is a way of achieving exactly what you wrote.

Maybe if you record the sequence in which updates ran and use that?

 

I want OnUpdate() to run as well. That will be used to execute code that does not need to be deterministic - such as animations and particles. Game-play/simulation code must be inside Tick().

Sounds like a hack I'd prefer a more robust approach.

 

The simplest solution seems to be:

Create a TickSystem with a method IsCurrentUpdateATick().
All other systems will call this method to check if the current OnUpdate() call is where deterministic code must be executed. This also seems to be more in line with Unity ECS's approach of not having instant callbacks, and instead doing everything through the OnUpdate() method.