59 lines
2.2 KiB
Rust
59 lines
2.2 KiB
Rust
extern crate cpal;
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extern crate failure;
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fn main() -> Result<(), failure::Error> {
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let device = cpal::default_output_device().expect("failed to find a default output device");
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let format = device.default_output_format()?;
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let event_loop = cpal::EventLoop::new();
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let stream_id = event_loop.build_output_stream(&device, &format)?;
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event_loop.play_stream(stream_id.clone())?;
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let sample_rate = format.sample_rate.0 as f32;
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let mut sample_clock = 0f32;
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// Produce a sinusoid of maximum amplitude.
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let mut next_value = || {
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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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event_loop.run(move |id, event| {
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let data = match event {
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cpal::StreamEvent::Data(data) => data,
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cpal::StreamEvent::Close(cpal::StreamCloseCause::Error(err)) => {
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eprintln!("stream {:?} closed due to an error: {}", id, err);
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return;
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}
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_ => return,
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};
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match data {
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cpal::StreamData::Output { buffer: cpal::UnknownTypeOutputBuffer::U16(mut buffer) } => {
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for sample in buffer.chunks_mut(format.channels as usize) {
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let value = ((next_value() * 0.5 + 0.5) * std::u16::MAX as f32) as u16;
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for out in sample.iter_mut() {
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*out = value;
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}
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}
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},
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cpal::StreamData::Output { buffer: cpal::UnknownTypeOutputBuffer::I16(mut buffer) } => {
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for sample in buffer.chunks_mut(format.channels as usize) {
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let value = (next_value() * std::i16::MAX as f32) as i16;
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for out in sample.iter_mut() {
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*out = value;
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}
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}
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},
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cpal::StreamData::Output { buffer: cpal::UnknownTypeOutputBuffer::F32(mut buffer) } => {
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for sample in buffer.chunks_mut(format.channels as usize) {
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let value = next_value();
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for out in sample.iter_mut() {
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*out = value;
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}
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}
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},
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_ => (),
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}
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});
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}
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