Crate pyri_state

source ·
Expand description

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 ResolveStateSet 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§