60 lines
1.8 KiB
Rust
60 lines
1.8 KiB
Rust
extern crate anyhow;
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extern crate cpal;
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use cpal::traits::{DeviceTrait, HostTrait, StreamTrait};
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fn main() -> Result<(), anyhow::Error> {
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let host = cpal::default_host();
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let device = host
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.default_output_device()
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.expect("failed to find a default output device");
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let format = device.default_output_format()?;
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let sample_rate = format.sample_rate.0 as f32;
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let channels = format.channels as usize;
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// Produce a sinusoid of maximum amplitude.
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let mut sample_clock = 0f32;
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let mut next_value = move || {
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sample_clock = (sample_clock + 1.0) % sample_rate;
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(sample_clock * 440.0 * 2.0 * 3.141592 / sample_rate).sin()
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};
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let err_fn = |err| eprintln!("an error occurred on stream: {}", err);
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let stream = match format.data_type {
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cpal::SampleFormat::F32 => device.build_output_stream(
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&format.shape(),
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move |data: &mut [f32]| write_data(data, channels, &mut next_value),
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err_fn,
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)?,
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cpal::SampleFormat::I16 => device.build_output_stream(
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&format.shape(),
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move |data: &mut [i16]| write_data(data, channels, &mut next_value),
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err_fn,
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)?,
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cpal::SampleFormat::U16 => device.build_output_stream(
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&format.shape(),
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move |data: &mut [u16]| write_data(data, channels, &mut next_value),
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err_fn,
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)?,
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};
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stream.play()?;
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std::thread::sleep(std::time::Duration::from_millis(1000));
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Ok(())
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}
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fn write_data<T>(output: &mut [T], channels: usize, next_sample: &mut dyn FnMut() -> f32)
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where
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T: cpal::Sample,
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{
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for frame in output.chunks_mut(channels) {
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let value: T = cpal::Sample::from::<f32>(&next_sample());
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for sample in frame.iter_mut() {
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*sample = value;
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}
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}
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}
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