docs/bevy/examples/app/plugin.rs 1.6 K · 52 lines · raw · history

1 //! Demonstrates the creation and registration of a custom plugin.
2 //!
3 //! Plugins are the foundation of Bevy. They are scoped sets of components, resources, and systems
4 //! that provide a specific piece of functionality (generally the smaller the scope, the better).
5 //! This example illustrates how to create a simple plugin that prints out a message.
6
7 use bevy::prelude::*;
8 use core::time::Duration;
9
10 fn main() {
11 App::new()
12 // plugins are registered as part of the "app building" process
13 .add_plugins((
14 DefaultPlugins,
15 PrintMessagePlugin {
16 wait_duration: Duration::from_secs(1),
17 message: "This is an example plugin".to_string(),
18 },
19 ))
20 .run();
21 }
22
23 // This "print message plugin" prints a `message` every `wait_duration`
24 struct PrintMessagePlugin {
25 // Put your plugin configuration here
26 wait_duration: Duration,
27 message: String,
28 }
29
30 impl Plugin for PrintMessagePlugin {
31 // this is where we set up our plugin
32 fn build(&self, app: &mut App) {
33 let state = PrintMessageState {
34 message: self.message.clone(),
35 timer: Timer::new(self.wait_duration, TimerMode::Repeating),
36 };
37 app.insert_resource(state)
38 .add_systems(Update, print_message_system);
39 }
40 }
41
42 #[derive(Resource)]
43 struct PrintMessageState {
44 message: String,
45 timer: Timer,
46 }
47
48 fn print_message_system(mut state: ResMut<PrintMessageState>, time: Res<Time>) {
49 if state.timer.tick(time.delta()).is_finished() {
50 info!("{}", state.message);
51 }
52 }