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use super::{Millisecond, Amplitude, SamplesPerSecond, Line};
pub struct Envelope {
pub attack: Line,
pub decay: Line,
pub release: Line,
}
impl Envelope {
pub fn new(
attack: Millisecond, decay: Millisecond, sustain: Amplitude, release: Millisecond, sample_rate: SamplesPerSecond
) -> Self {
let attack = Line::new(0.0, 1.0, attack, sample_rate);
let decay = Line::new(1.0, sustain, decay, sample_rate);
let release = Line::new(sustain, 0.0, release, sample_rate);
Self { attack, decay, release }
}
}
impl Iterator for Envelope {
type Item = Amplitude;
fn next(&mut self) -> Option<Self::Item> {
let mut val = self.attack.next();
if val.is_none() {
val = self.decay.next();
if val.is_none() {
self.release.next()
} else {
val
}
} else {
val
}
}
}
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