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bevy_event_set

A macro to create event bundles for Bevy 0.4

Crates.io GitHub

Standard practice in Bevy currently is declaring events as an enum. This is fine for many use cases, but in some situations you want to be able to listen for individual events in your systems while still being able to easily send multiple types of events (e.g. when parsing user input).

With the event_set macro, you can create an event set that allows you to send multiple event types.

Setup

Add the crate to your Cargo.toml dependencies:

[dependencies]
bevy_event_set = "0.2"

A bug in a subcrate of Bevy 0.4 prevents this crate from working properly. Add the following patch to your Cargo.toml to apply the fix:

[patch.crates-io]
bevy_ecs_macros = { git = "https://github.com/woubuc/bevy", branch = "fix/ecs-macro-systemparam-0.4" }

This bug is fixed in Bevy with PR #1434.

Usage

use bevy::prelude::*;
use bevy_event_set::*;

// Define your events
struct EventOne;
struct EventTwo;
struct EventThree(usize);

// Create an event set named `MyEvents`
event_set!(MyEvents { EventOne, EventTwo, EventThree });

// Use the event set in a system
fn event_emitter_system(mut events: MyEvents) {
    events.send(EventOne);
    events.send(EventTwo);
    events.send(EventThree(42));
}

// Subscribe to events selectively in different systems
fn event_one_listener_system(events: Res<Events<EventOne>>) { }
fn event_two_listener_system(events: Res<Events<EventTwo>>) { }
fn event_three_listener_system(events: Res<Events<EventThree>>) { }

// Add the event set to your app
App::build()
    .add_event_set::<MyEvents>();

Notes

  • Supports Bevy 0.4
  • Basically works, but keep in mind that the code is very basic
  • I welcome contributions to make this a little more versatile/user-friendly