cpal/examples/beep.rs

61 lines
2.2 KiB
Rust

extern crate cpal;
extern crate failure;
use cpal::{Device, EventLoop, Host};
fn main() -> Result<(), failure::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 event_loop = host.event_loop();
let stream_id = event_loop.build_output_stream(&device, &format)?;
event_loop.play_stream(stream_id.clone())?;
let sample_rate = format.sample_rate.0 as f32;
let mut sample_clock = 0f32;
// Produce a sinusoid of maximum amplitude.
let mut next_value = || {
sample_clock = (sample_clock + 1.0) % sample_rate;
(sample_clock * 440.0 * 2.0 * 3.141592 / sample_rate).sin()
};
event_loop.run(move |id, result| {
let data = match result {
Ok(data) => data,
Err(err) => {
eprintln!("an error occurred on stream {:?}: {}", id, err);
return;
}
};
match data {
cpal::StreamData::Output { buffer: cpal::UnknownTypeOutputBuffer::U16(mut buffer) } => {
for sample in buffer.chunks_mut(format.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(format.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(format.channels as usize) {
let value = next_value();
for out in sample.iter_mut() {
*out = value;
}
}
},
_ => (),
}
});
}