bevy/crates/bevy_audio/src/pitch.rs
Rob Parrett 39c68e3f92
More ergonomic spatial audio (#9800)
# Objective

Spatial audio was heroically thrown together at the last minute for Bevy
0.10, but right now it's a bit of a pain to use -- users need to
manually update audio sinks with the position of the listener / emitter.

Hopefully the migration guide entry speaks for itself.

## Solution

Add a new `SpatialListener` component and automatically update sinks
with the position of the listener and and emitter.

## Changelog

`SpatialAudioSink`s are now automatically updated with positions of
emitters and listeners.

## Migration Guide

Spatial audio now automatically uses the transform of the `AudioBundle`
and of an entity with a `SpatialListener` component.

If you were manually scaling emitter/listener positions, you can use the
`spatial_scale` field of `AudioPlugin` instead.

```rust

// Old

commands.spawn(
    SpatialAudioBundle {
        source: asset_server.load("sounds/Windless Slopes.ogg"),
        settings: PlaybackSettings::LOOP,
        spatial: SpatialSettings::new(listener_position, gap, emitter_position),
    },
);

fn update(
    emitter_query: Query<(&Transform, &SpatialAudioSink)>,
    listener_query: Query<&Transform, With<Listener>>,
) {
    let listener = listener_query.single();

    for (transform, sink) in &emitter_query {
        sink.set_emitter_position(transform.translation);
        sink.set_listener_position(*listener, gap);
    }
}

// New

commands.spawn((
    SpatialBundle::from_transform(Transform::from_translation(emitter_position)),
    AudioBundle {
        source: asset_server.load("sounds/Windless Slopes.ogg"),
        settings: PlaybackSettings::LOOP.with_spatial(true),
    },
));

commands.spawn((
    SpatialBundle::from_transform(Transform::from_translation(listener_position)),
    SpatialListener::new(gap),
));
```

## Discussion

I removed `SpatialAudioBundle` because the `SpatialSettings` component
was made mostly redundant, and without that it was identical to
`AudioBundle`.

`SpatialListener` is a bare component and not a bundle which is feeling
like a maybe a strange choice. That happened from a natural aversion
both to nested bundles and to duplicating `Transform` etc in bundles and
from figuring that it is likely to just be tacked on to some other
bundle (player, head, camera) most of the time.

Let me know what you think about these things / everything else.

---------

Co-authored-by: Mike <mike.hsu@gmail.com>
2023-10-09 19:43:56 +00:00

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Rust

use crate::{AudioSourceBundle, Decodable};
use bevy_asset::Asset;
use bevy_reflect::TypePath;
use rodio::{source::SineWave, source::TakeDuration, Source};
/// A source of sine wave sound
#[derive(Asset, Debug, Clone, TypePath)]
pub struct Pitch {
/// Frequency at which sound will be played
pub frequency: f32,
/// Duration for which sound will be played
pub duration: std::time::Duration,
}
impl Pitch {
/// Creates a new note
pub fn new(frequency: f32, duration: std::time::Duration) -> Self {
Pitch {
frequency,
duration,
}
}
}
impl Decodable for Pitch {
type DecoderItem = <SineWave as Iterator>::Item;
type Decoder = TakeDuration<SineWave>;
fn decoder(&self) -> Self::Decoder {
SineWave::new(self.frequency).take_duration(self.duration)
}
}
/// Bundle for playing a bevy note sound
pub type PitchBundle = AudioSourceBundle<Pitch>;