Bevy Kira audio

This bevy plugin is intended to test an integration of Kira into Bevy. The goal is to replace or update bevy_audio, if Kira turns out to be a good approach. Currently, this plugin can play ogg, mp3, flac, and wav formats and supports web builds.

Sound can be played in channels. Each channel has controls to pause or stop playback and can change the volume, playback speed, and panning of all sounds playing in it. You can easily add new channels and access them through Bevy's ECS (see the custom_channel example).

Usage

Note: the Bevy feature bevy_audio is enabled by default and not compatible with this plugin. Make sure to not have the bevy_audio feature enabled if you want to use bevy_kira_audio. The same goes for Bevy's vorbis feature. See Bevys' Cargo file for a list of all default features of version 0.14 and list them manually in your Cargo file excluding the ones you do not want. Make sure to set default-features to false for the Bevy dependency. You can take a look at bevy_game_template's cargo file as an example.

To play audio, you usually want to load audio files as assets. This requires AssetLoaders. bevy_kira_audio comes with loaders for most common audio formats. You can enable them with the features ogg (enabled by default), mp3, wav, or flac. The following example assumes that the feature ogg is enabled.

use bevy_kira_audio::prelude::*;
use bevy::prelude::*;

fn main() {
   App::new()
        .add_plugins((DefaultPlugins, AudioPlugin))
        .add_systems(Startup, start_background_audio)
        .run();
}

fn start_background_audio(asset_server: Res<AssetServer>, audio: Res<Audio>) {
    audio.play(asset_server.load("background_audio.ogg")).looped();
}

You can change settings like volume, panning, or playback rate for running sounds, or when starting to play a sound. All changes can be done as smooth transitions. By default, they will be almost instantaneous.

Sound settings

You can configure a sound when playing it:

use bevy_kira_audio::prelude::*;
use bevy::prelude::*;
use std::time::Duration;

fn play_audio(asset_server: Res<AssetServer>, audio: Res<Audio>) {
    audio.play(asset_server.load("background_audio.ogg"))
        // The first 0.5 seconds will not be looped and are the "intro"
        .loop_from(0.5)
        // Fade-in with a dynamic easing
        .fade_in(AudioTween::new(Duration::from_secs(2), AudioEasing::OutPowi(2)))
        // Only play on our right ear
        .with_panning(1.0)
        // Increase playback rate by 50% (this also increases the pitch)
        .with_playback_rate(1.5)
        // Play at half volume
        .with_volume(0.5)
        // play the track reversed
        .reverse();
}

Optionally, you can also load a sound with already applied settings. This requires the feature settings_loader.

Sounds are configured in ron files. The following file loads as a AudioSource which is looped and has a 3 seconds intro before the loop:

(
    // The actual sound file in your assets directory
    file: "sounds/loop.ogg",

    loop_behavior: Some(3.0),
)

would make the loaded sound loop by default and start each repeated playback three seconds into the sound (the three seconds are the intro).

More settings are available. See the settings_loader example for all options.

Controlling sounds

You can either control a whole audio channel and all instances playing in it (channel_control example), or a single audio instance (instance_control example). Both ways offer audio transitions with Tweens supporting multiple easings.

Spatial audio

There is limited spatial audio support. Currently, only the volume of audio and it's panning can be automatically changed based on emitter and receiver positions. Take a look at the spatial example for some code.

Compatible Bevy versions

The main branch is compatible with the latest Bevy release.

Compatibility of bevy_kira_audio versions:

License

Dual-licensed under either of

• Apache License, Version 2.0, (LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or https://opensource.org/licenses/MIT)

at your option.

Assets in the examples might be distributed under different terms. See the readme in the examples directory.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.