shrooms-vb-native/src/audio.rs

102 lines
3.6 KiB
Rust

use anyhow::{bail, Result};
use cpal::traits::{DeviceTrait, HostTrait, StreamTrait};
use itertools::Itertools;
use rubato::{FftFixedInOut, Resampler};
pub struct Audio {
#[allow(unused)]
stream: cpal::Stream,
sampler: FftFixedInOut<f32>,
input_buffer: Vec<Vec<f32>>,
output_buffer: Vec<Vec<f32>>,
sample_sink: rtrb::Producer<f32>,
}
impl Audio {
pub fn init() -> Result<Self> {
let host = cpal::default_host();
let Some(device) = host.default_output_device() else {
bail!("No output device available");
};
let Some(config) = device
.supported_output_configs()?
.find(|c| c.channels() == 2 && c.sample_format().is_float())
else {
bail!("No suitable output config available");
};
let mut config = config.with_max_sample_rate().config();
let sampler = FftFixedInOut::new(41700, config.sample_rate.0 as usize, 834, 2)?;
config.buffer_size = cpal::BufferSize::Fixed(sampler.output_frames_max() as u32);
let input_buffer = sampler.input_buffer_allocate(true);
let output_buffer = sampler.output_buffer_allocate(true);
let (sample_sink, mut sample_source) =
rtrb::RingBuffer::new(sampler.output_frames_max() * 4);
let stream = device.build_output_stream(
&config,
move |data: &mut [f32], _| {
let requested = data.len();
let chunk = match sample_source.read_chunk(data.len()) {
Ok(c) => c,
Err(rtrb::chunks::ChunkError::TooFewSlots(n)) => {
sample_source.read_chunk(n).unwrap()
}
};
let len = chunk.len();
let (first, second) = chunk.as_slices();
data[0..first.len()].copy_from_slice(first);
data[first.len()..len].copy_from_slice(second);
for rest in &mut data[len..requested] {
*rest = 0.0;
}
chunk.commit_all();
},
move |err| eprintln!("stream error: {err}"),
None,
)?;
stream.play()?;
Ok(Self {
stream,
sampler,
input_buffer,
output_buffer,
sample_sink,
})
}
pub fn update(&mut self, samples: &[f32]) {
for sample in samples.chunks_exact(2) {
for (channel, value) in self.input_buffer.iter_mut().zip(sample) {
channel.push(*value);
}
if self.input_buffer[0].len() >= self.sampler.input_frames_next() {
let (_, output_samples) = self
.sampler
.process_into_buffer(&self.input_buffer, &mut self.output_buffer, None)
.unwrap();
let chunk = match self.sample_sink.write_chunk_uninit(output_samples * 2) {
Ok(c) => c,
Err(rtrb::chunks::ChunkError::TooFewSlots(n)) => {
self.sample_sink.write_chunk_uninit(n).unwrap()
}
};
let interleaved = self.output_buffer[0]
.iter()
.interleave(self.output_buffer[1].iter())
.cloned();
chunk.fill_from_iter(interleaved);
for channel in &mut self.input_buffer {
channel.clear();
}
}
}
while self.sample_sink.slots() < self.sampler.output_frames_max() * 2 {
std::hint::spin_loop();
}
}
}