# Objective - Contributes to #11478 - Contributes to #16877 ## Solution - Removed everything except `Instant` from `bevy_utils::time` ## Testing - CI --- ## Migration Guide If you relied on any of the following from `bevy_utils::time`: - `Duration` - `TryFromFloatSecsError` Import these directly from `core::time` regardless of platform target (WASM, mobile, etc.) If you relied on any of the following from `bevy_utils::time`: - `SystemTime` - `SystemTimeError` Instead import these directly from either `std::time` or `web_time` as appropriate for your target platform. ## Notes `Duration` and `TryFromFloatSecsError` are both re-exports from `core::time` regardless of whether they are used from `web_time` or `std::time`, so there is no value gained from re-exporting them from `bevy_utils::time` as well. As for `SystemTime` and `SystemTimeError`, no Bevy internal crates or examples rely on these types. Since Bevy doesn't have a `Time<Wall>` resource for interacting with wall-time (and likely shouldn't need one), I think removing these from `bevy_utils` entirely and waiting for a use-case to justify inclusion is a reasonable path forward.
		
			
				
	
	
		
			104 lines
		
	
	
		
			2.9 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
			
		
		
	
	
			104 lines
		
	
	
		
			2.9 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
//! Shows how to create a custom [`Decodable`] type by implementing a Sine wave.
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use bevy::{
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    audio::{AddAudioSource, AudioPlugin, Source},
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    math::ops,
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    prelude::*,
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    reflect::TypePath,
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};
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use core::time::Duration;
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// This struct usually contains the data for the audio being played.
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// This is where data read from an audio file would be stored, for example.
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// This allows the type to be registered as an asset.
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#[derive(Asset, TypePath)]
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struct SineAudio {
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    frequency: f32,
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}
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// This decoder is responsible for playing the audio,
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// and so stores data about the audio being played.
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struct SineDecoder {
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    // how far along one period the wave is (between 0 and 1)
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    current_progress: f32,
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    // how much we move along the period every frame
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    progress_per_frame: f32,
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    // how long a period is
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    period: f32,
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    sample_rate: u32,
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}
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impl SineDecoder {
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    fn new(frequency: f32) -> Self {
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        // standard sample rate for most recordings
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        let sample_rate = 44_100;
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        SineDecoder {
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            current_progress: 0.,
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            progress_per_frame: frequency / sample_rate as f32,
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            period: std::f32::consts::PI * 2.,
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            sample_rate,
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        }
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    }
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}
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// The decoder must implement iterator so that it can implement `Decodable`.
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impl Iterator for SineDecoder {
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    type Item = f32;
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    fn next(&mut self) -> Option<Self::Item> {
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        self.current_progress += self.progress_per_frame;
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        // we loop back round to 0 to avoid floating point inaccuracies
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        self.current_progress %= 1.;
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        Some(ops::sin(self.period * self.current_progress))
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    }
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}
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// `Source` is what allows the audio source to be played by bevy.
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// This trait provides information on the audio.
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impl Source for SineDecoder {
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    fn current_frame_len(&self) -> Option<usize> {
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        None
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    }
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    fn channels(&self) -> u16 {
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        1
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    }
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    fn sample_rate(&self) -> u32 {
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        self.sample_rate
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    }
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    fn total_duration(&self) -> Option<Duration> {
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        None
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    }
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}
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// Finally `Decodable` can be implemented for our `SineAudio`.
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impl Decodable for SineAudio {
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    type DecoderItem = <SineDecoder as Iterator>::Item;
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    type Decoder = SineDecoder;
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    fn decoder(&self) -> Self::Decoder {
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        SineDecoder::new(self.frequency)
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    }
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}
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fn main() {
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    let mut app = App::new();
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    // register the audio source so that it can be used
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    app.add_plugins(DefaultPlugins.set(AudioPlugin {
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        global_volume: GlobalVolume::new(0.2),
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        ..default()
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    }))
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    .add_audio_source::<SineAudio>()
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    .add_systems(Startup, setup)
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    .run();
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}
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fn setup(mut assets: ResMut<Assets<SineAudio>>, mut commands: Commands) {
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    // add a `SineAudio` to the asset server so that it can be played
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    let audio_handle = assets.add(SineAudio {
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        frequency: 440., // this is the frequency of A4
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    });
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    commands.spawn(AudioPlayer(audio_handle));
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}
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