cpal/examples/beep.rs

57 lines
2.1 KiB
Rust

extern crate anyhow;
extern crate cpal;
use cpal::traits::{DeviceTrait, StreamTrait, HostTrait};
fn main() -> Result<(), anyhow::Error> {
let host = cpal::default_host();
let device = host.default_output_device().expect("failed to find a default output device");
let format = device.default_output_format()?;
let sample_rate = format.sample_rate.0 as f32;
let channels = format.channels;
let mut sample_clock = 0f32;
// Produce a sinusoid of maximum amplitude.
let mut next_value = move || {
sample_clock = (sample_clock + 1.0) % sample_rate;
(sample_clock * 440.0 * 2.0 * 3.141592 / sample_rate).sin()
};
let stream = device.build_output_stream(&format, move |data| {
match data {
cpal::StreamData::Output { buffer: cpal::UnknownTypeOutputBuffer::U16(mut buffer) } => {
for sample in buffer.chunks_mut(channels as usize) {
let value = ((next_value() * 0.5 + 0.5) * std::u16::MAX as f32) as u16;
for out in sample.iter_mut() {
*out = value;
}
}
},
cpal::StreamData::Output { buffer: cpal::UnknownTypeOutputBuffer::I16(mut buffer) } => {
for sample in buffer.chunks_mut(channels as usize) {
let value = (next_value() * std::i16::MAX as f32) as i16;
for out in sample.iter_mut() {
*out = value;
}
}
},
cpal::StreamData::Output { buffer: cpal::UnknownTypeOutputBuffer::F32(mut buffer) } => {
for sample in buffer.chunks_mut(channels as usize) {
let value = next_value();
for out in sample.iter_mut() {
*out = value;
}
}
},
_ => (),
}
}, move |err| {
eprintln!("an error occurred on stream: {}", err);
})?;
stream.play()?;
std::thread::sleep(std::time::Duration::from_millis(1000));
Ok(())
}