Determinism

[SpindizzyGames]

Is Unity ECS itself (NOT the Physics package) cross platform determinstic? Can I use it in rollback netcode to restore ECS world state?

[koonm]

not now，maybe someday!
you can see DOTS roadmap | Unity, Burst Determinism just under consideration.

[TheOtherMonarch]

Roll back is also broken for the last 2 years.

Implement rollback and working around bug with CopyAndReplaceEntitiesFrom

I’ve looked into many ways to do rollback, which is creating a copy of the world at a specific frame and then restoring that world and simulating back to the current frame with updated inputs. The easiest way to implement it was with CopyAndReplaceEntitiesFrom to just copy and replace into a backup world then copy and replace back into the active world. Unfortunately this bug Unity Issue Tracker - Not every component is copied consistently with CopyAndReplaceEntitiesFrom and causes Player to cra…

[Selmar]

@SpindizzyGames

Is Unity ECS itself (NOT the Physics package) cross platform determinstic? Can I use it in rollback netcode to restore ECS world state?

From what I have experienced so far, which is somewhat limited, it is deterministic as long as you do not use floating point operations (which is a difficult subject to tackle).

As TheOtherMonarch mentioned, rollback isn’t working right now, but we do have a prototype working in lockstep.