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use std::f32::consts::TAU;
use rand::Rng;
use super::{Hz, Sample};
use super::phasor::Phasor;
/// The various waveforms the `MonoSynth` can generate.
pub enum Waveform {
Sine,
Square,
Triangle,
Sawtooth,
WhiteNoise,
BrownNoise,
}
pub struct Osc {
pub phasor: Phasor,
pub waveform: Waveform,
pub last_value: Sample,
}
impl Osc {
pub fn new(frequency: Hz, sample_rate: f32) -> Self {
Self {
phasor: Phasor::new(frequency, sample_rate),
waveform: Waveform::Sine,
last_value: 0.1,
}
}
pub fn get_frequency(&self) -> Hz {
self.phasor.frequency
}
pub fn set_frequency(&mut self, frequency: Hz) {
self.phasor.frequency = frequency;
}
pub fn sample(&mut self) -> Sample {
match self.next() {
Some(s) => { s },
None => 0.0
}
}
}
impl Iterator for Osc {
type Item = Sample;
fn next(&mut self) -> Option<Self::Item> {
let phase = self.phasor.next().unwrap();
let mut rng = rand::thread_rng();
let sample = match self.waveform {
Waveform::Sine => {
(TAU * phase).sin()
},
Waveform::Square => {
if phase < 0.5 {
-1.0
} else {
1.0
}
},
Waveform::Triangle => {
if phase < 0.5 {
4.0 * phase - 1.0
} else {
4.0 * (1.0 - phase) - 1.0
}
},
Waveform::Sawtooth => {
2.0 * phase - 1.0
},
Waveform::WhiteNoise => {
(rng.gen::<f32>()).sin()
},
Waveform::BrownNoise => {
(self.last_value + (rng.gen::<f32>()) * 0.2 - 0.1).clamp(-1.0, 1.0)
},
};
Some(sample)
}
}
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