breakers 0.1.4

Interpreter for the Breaker livecoding language
Documentation 
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/*!
* The audio engine module.
*
* This module is responsible for setting up the audio output,
* and for sending the audio samples to the output device.
*
* The audio engine is a separate thread, which receives the audio samples.
*/

use std::{
    sync::mpsc::Receiver,
    time::{SystemTime, UNIX_EPOCH},
};

use cpal::{
    traits::{DeviceTrait, HostTrait},
    Stream, SupportedStreamConfig,
};

pub fn start(source: Receiver<f32>) -> (Stream, SupportedStreamConfig) {
    let host = cpal::host_from_id(
        cpal::available_hosts()
            .into_iter()
            .find(|id| *id == cpal::HostId::Jack)
            .expect("make sure --features jack is specified"),
    )
    .expect("jack host unavailable");

    let device = host.default_output_device().unwrap();

    let config = device.default_output_config().unwrap();

    let err_fn = |err| eprintln!("an error occurred on input stream: {err}");

    let out_stream = device.build_output_stream(
        &config.config(),
        move |data: &mut [f32], _: &cpal::OutputCallbackInfo| {
            for (_, frame) in data.chunks_mut(2).enumerate() {
                let Ok(sample) = source.recv() else {
                    println!("Some receiving error at the audio engine side");
                    continue;
                };
                log::trace!(
                    "audio_engine, {}",
                    SystemTime::now()
                        .duration_since(UNIX_EPOCH)
                        .unwrap()
                        .as_nanos()
                );
                for ch in frame {
                    *ch = sample;
                }
            }
        },
        err_fn,
        None,
    );

    (out_stream.unwrap(), config)
}