Crate pyri_state

pyri_state is a bevy_state alternative offering flexible change detection & scheduling.

NOTE: This crate is incompatible with the bevy/bevy_state feature, so make sure it’s disabled.

Overview

1. The current state is a Resource or Component that implements State.
2. The next state is stored in a NextStateBuffer resource by default.
3. A state flush is triggered by the TriggerStateFlush resource and handled in the StateFlush schedule.
4. State flush hooks are organized into ResolveStateSystems system sets.
5. Tools are provided for state setup, access, pattern-matching, debugging, and more.

Getting started

Import the prelude to bring traits and common types into scope:

use pyri_state::prelude::*;

Define your own State type using the derive macro:

#[derive(State, Clone, PartialEq, Eq, Default)]
struct Level(pub usize);

Add StatePlugin and initialize your state type:

app.add_plugins(StatePlugin).init_state::<Level>();

Add update systems with StatePattern::on_update:

app.add_systems(Update, (
    Level::ANY.on_update(update_level_timer),
    Level(10).on_update(update_boss_health_bar),
    state!(Level(4..=6)).on_update(spawn_enemy_waves),
));

Add flush hooks with other StatePattern methods:

app.add_systems(StateFlush, (
    // Short-hand for `on_exit` followed by `on_enter`.
    Level::ANY.on_edge(despawn_old_level, spawn_new_level),
    Level(10).on_enter(play_boss_music),
    state!(Level(4 | 7 | 10)).on_enter(save_checkpoint),
    Level::with(|x| x.0 < 4).on_enter(spawn_tutorial_popup),
));

Modules

access

System parameters to access current and next states.

debug

State debugging tools.

extra

Extra tools behind feature flags.

next_state

NextState trait, extension traits and types.

pattern

State pattern-matching tools.

prelude

Re-exported traits and common types.

schedule

State flush scheduling types and functions.

setup

State setup and configuration tools.

state

State trait and extension traits.

Macros

add_to_split_state

A macro for extending SplitState newtypes.

state

A macro for building pattern-matching FnStatePattern and FnStateTransPattern instances.