bevy/examples/audio/audio_control.rs

//! This example illustrates how to load and play an audio file, and control how it's played.

use bevy::{math::ops, prelude::*};

fn main() {
    App::new()
        .add_plugins(DefaultPlugins)
        .add_systems(Startup, setup)
        .add_systems(Update, (update_speed, pause, volume))
        .run();
}

fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
    commands.spawn((
        AudioPlayer::<AudioSource>(asset_server.load("sounds/Windless Slopes.ogg")),
        MyMusic,
    ));
}

#[derive(Component)]
struct MyMusic;

fn update_speed(music_controller: Query<&AudioSink, With<MyMusic>>, time: Res<Time>) {
    if let Ok(sink) = music_controller.get_single() {
        sink.set_speed((ops::sin(time.elapsed_secs() / 5.0) + 1.0).max(0.1));
    }
}

fn pause(
    keyboard_input: Res<ButtonInput<KeyCode>>,
    music_controller: Query<&AudioSink, With<MyMusic>>,
) {
    if keyboard_input.just_pressed(KeyCode::Space) {
        if let Ok(sink) = music_controller.get_single() {
            sink.toggle();
        }
    }
}

fn volume(
    keyboard_input: Res<ButtonInput<KeyCode>>,
    music_controller: Query<&AudioSink, With<MyMusic>>,
) {
    if let Ok(sink) = music_controller.get_single() {
        if keyboard_input.just_pressed(KeyCode::Equal) {
            sink.set_volume(sink.volume() + 0.1);
        } else if keyboard_input.just_pressed(KeyCode::Minus) {
            sink.set_volume(sink.volume() - 0.1);
        }
    }
}