rodio/src/dynamic_mixer.rs

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//! Queue that plays sounds one after the other.
use std::sync::Arc;
use std::sync::Mutex;
use std::sync::atomic::AtomicBool;
use std::sync::atomic::Ordering;
use std::time::Duration;
use source::Source;
use source::UniformSourceIterator;
use Sample;
/// Builds a new mixer.
///
/// You can choose the characteristics of the output thanks to this constructor. All the sounds
/// added to the mixer will be converted to these values.
///
/// After creating a mixer, you can add new sounds with the controller.
pub fn mixer<S>(channels: u16, samples_rate: u32) -> (Arc<DynamicMixerController<S>>, DynamicMixer<S>)
where S: Sample + Send + 'static
{
let input = Arc::new(DynamicMixerController {
has_pending: AtomicBool::new(false),
pending_sources: Mutex::new(Vec::new()),
channels: channels,
samples_rate: samples_rate,
});
let output = DynamicMixer {
current_sources: Vec::with_capacity(16),
input: input.clone(),
};
(input, output)
}
/// The input of the mixer.
pub struct DynamicMixerController<S> {
has_pending: AtomicBool,
pending_sources: Mutex<Vec<Box<Source<Item = S> + Send>>>,
channels: u16,
samples_rate: u32,
}
impl<S> DynamicMixerController<S> where S: Sample + Send + 'static {
/// Adds a new source to mix to the existing ones.
#[inline]
pub fn add<T>(&self, source: T)
where T: Source<Item = S> + Send + 'static
{
let uniform_source = UniformSourceIterator::new(source, self.channels, self.samples_rate);
self.pending_sources.lock().unwrap().push(Box::new(uniform_source) as Box<_>);
self.has_pending.store(true, Ordering::SeqCst); // TODO: can we relax this ordering?
}
}
/// The output of the mixer. Implements `Source`.
pub struct DynamicMixer<S> {
// The current iterator that produces samples.
current_sources: Vec<Box<Source<Item = S> + Send>>,
// The pending sounds.
input: Arc<DynamicMixerController<S>>,
}
impl<S> Source for DynamicMixer<S> where S: Sample + Send + 'static {
#[inline]
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fn current_frame_len(&self) -> Option<usize> {
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None
}
#[inline]
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fn channels(&self) -> u16 {
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self.input.channels
}
#[inline]
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fn samples_rate(&self) -> u32 {
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self.input.samples_rate
}
#[inline]
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fn total_duration(&self) -> Option<Duration> {
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None
}
}
impl<S> Iterator for DynamicMixer<S> where S: Sample + Send + 'static {
type Item = S;
#[inline]
fn next(&mut self) -> Option<S> {
if self.input.has_pending.load(Ordering::SeqCst) { // TODO: relax ordering?
let mut pending = self.input.pending_sources.lock().unwrap();
self.current_sources.extend(pending.drain(..));
self.input.has_pending.store(false, Ordering::SeqCst); // TODO: relax ordering?
}
if self.current_sources.is_empty() {
return None;
}
let mut to_drop = Vec::new();
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let mut sum = S::zero_value();
for (num, src) in self.current_sources.iter_mut().enumerate() {
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if let Some(val) = src.next() {
sum = sum.saturating_add(val);
} else {
to_drop.push(num);
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}
}
for &td in to_drop.iter().rev() {
self.current_sources.remove(td);
}
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if self.current_sources.is_empty() {
None
} else {
Some(sum)
}
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}
#[inline]
fn size_hint(&self) -> (usize, Option<usize>) {
(0, None)
}
}
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#[cfg(test)]
mod tests {
use dynamic_mixer;
use buffer::SamplesBuffer;
use source::Source;
#[test]
fn basic() {
let (tx, mut rx) = dynamic_mixer::mixer(1, 48000);
tx.add(SamplesBuffer::new(1, 48000, vec![10i16, -10, 10, -10]));
tx.add(SamplesBuffer::new(1, 48000, vec![5i16, 5, 5, 5]));
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assert_eq!(rx.channels(), 1);
assert_eq!(rx.samples_rate(), 48000);
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assert_eq!(rx.next(), Some(15));
assert_eq!(rx.next(), Some(-5));
assert_eq!(rx.next(), Some(15));
assert_eq!(rx.next(), Some(-5));
assert_eq!(rx.next(), None);
}
#[test]
fn channels_conv() {
let (tx, mut rx) = dynamic_mixer::mixer(2, 48000);
tx.add(SamplesBuffer::new(1, 48000, vec![10i16, -10, 10, -10]));
tx.add(SamplesBuffer::new(1, 48000, vec![5i16, 5, 5, 5]));
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assert_eq!(rx.channels(), 2);
assert_eq!(rx.samples_rate(), 48000);
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assert_eq!(rx.next(), Some(15));
assert_eq!(rx.next(), Some(15));
assert_eq!(rx.next(), Some(-5));
assert_eq!(rx.next(), Some(-5));
assert_eq!(rx.next(), Some(15));
assert_eq!(rx.next(), Some(15));
assert_eq!(rx.next(), Some(-5));
assert_eq!(rx.next(), Some(-5));
assert_eq!(rx.next(), None);
}
#[test]
fn rate_conv() {
let (tx, mut rx) = dynamic_mixer::mixer(1, 96000);
tx.add(SamplesBuffer::new(1, 48000, vec![10i16, -10, 10, -10]));
tx.add(SamplesBuffer::new(1, 48000, vec![5i16, 5, 5, 5]));
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assert_eq!(rx.channels(), 1);
assert_eq!(rx.samples_rate(), 96000);
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assert_eq!(rx.next(), Some(15));
assert_eq!(rx.next(), Some(5));
assert_eq!(rx.next(), Some(-5));
assert_eq!(rx.next(), Some(5));
assert_eq!(rx.next(), Some(15));
assert_eq!(rx.next(), Some(5));
assert_eq!(rx.next(), Some(-5));
assert_eq!(rx.next(), None);
}
}