#gamedev #bevy

bevy_roll_safe

Rollback safe utilities and abstractions for Bevy

1 unstable release

0.1.0 Nov 14, 2023

#1702 in Game dev

37 downloads per month

MIT/Apache

19KB
76 lines

bevy_roll_safe

crates.io MIT/Apache 2.0 docs.rs

Rollback-safe implementations and utilities for Bevy Engine.

Motivation

Some of Bevy's features can't be used in a rollback context (with crates such as bevy_ggrs). This is either because they behave non-deterministically, rely on inaccessible local system state, or are tightly coupled to the Main schedule.

Roadmap

  • States
  • FrameCount
  • Events

States

Bevy states when added through app.add_state::<FooState>() have two big problems:

  1. They happen in the StateTransition schedule within the MainSchedule
  2. If rolled back to the first frame, OnEnter(InitialState) is not re-run.

This crate provides an extension method, add_roll_state::<S>(schedule), which lets you add a state to the schedule you want, and a resource, InitialStateEntered<S> which can be rolled back and tracks whether the initial OnEnter should be run (or re-run on rollbacks to the initial frame).

See the states example for usage with bevy_ggrs.

Cargo features

  • bevy_ggrs: Enable integration with bevy_ggrs
  • math_determinism: Enable cross-platform determinism for operations on Bevy's (glam) math types.

Bevy Version Support

bevy bevy_roll_safe
0.12 0.1, main

License

bevy_roll_safe is dual-licensed under either

at your option.

Contributions

PRs welcome!

Dependencies

~21MB
~405K SLoC