tuxmain/HexoDSP
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

documented the PolyBlepOscillator

Browse source
This commit is contained in:
Weird Constructor 2021-08-01 06:43:17 +02:00
parent 3cbe0111cc
commit b974ed0bd7
1 changed files with 132 additions and 6 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

138
src/dsp/helpers.rs
View file

@ -1205,6 +1205,33 @@ fn poly_blep(t: f32, dt: f32) -> f32 {
}
}
/// This is a band-limited oscillator based on the PolyBlep technique.
/// Here is a quick example on how to use it:
///
///```
/// use HexoDSP::dsp::helpers::{PolyBlepOscillator, rand_01};
///
/// // Randomize the initial phase to make cancellation on summing less
/// // likely:
/// let mut osc =
/// PolyBlepOscillator::new(rand_01() * 0.25);
///
///
/// let freq = 440.0; // Hz
/// let israte = 1.0 / 44100.0; // Seconds per Sample
/// let pw = 0.2; // Pulse-Width for the next_pulse()
/// let waveform = 0; // 0 being pulse in this example, 1 being sawtooth
///
/// // in your process function:
/// for output_sample in block_of_samples.iter_mut() {
/// *output_sample =
/// if waveform == 1 {
/// osc.next_saw(freq, israte)
/// } else {
/// osc.next_pulse(freq, israte, pw)
/// }
/// }
///```
#[derive(Debug, Clone)]
pub struct PolyBlepOscillator {
phase: f32,
@ -1213,6 +1240,18 @@ pub struct PolyBlepOscillator {
}
impl PolyBlepOscillator {
/// Create a new instance of [PolyBlepOscillator].
///
/// * `init_phase` - Initial phase of the oscillator.
/// Range of this parameter is from 0.0 to 1.0. Passing a random
/// value is advised for preventing phase cancellation when summing multiple
/// oscillators.
///
///```
/// use HexoDSP::dsp::helpers::{PolyBlepOscillator, rand_01};
///
/// let mut osc = PolyBlepOscillator::new(rand_01() * 0.25);
///```
pub fn new(init_phase: f32) -> Self {
Self {
phase: 0.0,
@ -1221,18 +1260,30 @@ impl PolyBlepOscillator {
}
}
/// Reset the internal state of the oscillator as if you just called
/// [PolyBlepOscillator::new].
#[inline]
pub fn reset(&mut self) {
self.phase = self.init_phase;
self.last_output = 0.0;
}
// #[inline]
// pub fn next_tri(&mut self) -> f32 {
// let value = -1.0 + (2.0 * self.phase);
// 2.0 * (value.abs() - 0.5)
// }
/// Creates the next sample of a sine wave.
///
/// * `freq` - The frequency in Hz.
/// * `israte` - The inverse sampling rate, or seconds per sample as in eg. `1.0 / 44100.0`.
///```
/// use HexoDSP::dsp::helpers::{PolyBlepOscillator, rand_01};
///
/// let mut osc = PolyBlepOscillator::new(rand_01() * 0.25);
///
/// let freq = 440.0; // Hz
/// let israte = 1.0 / 44100.0; // Seconds per Sample
///
/// // ...
/// let sample = osc.next_sin(freq, israte);
/// // ...
///```
#[inline]
pub fn next_sin(&mut self, freq: f32, israte: f32) -> f32 {
let phase_inc = freq * israte;
@ -1245,6 +1296,23 @@ impl PolyBlepOscillator {
s as f32
}
/// Creates the next sample of a triangle wave. Please note that the
/// bandlimited waveform needs a few initial samples to swing in.
///
/// * `freq` - The frequency in Hz.
/// * `israte` - The inverse sampling rate, or seconds per sample as in eg. `1.0 / 44100.0`.
///```
/// use HexoDSP::dsp::helpers::{PolyBlepOscillator, rand_01};
///
/// let mut osc = PolyBlepOscillator::new(rand_01() * 0.25);
///
/// let freq = 440.0; // Hz
/// let israte = 1.0 / 44100.0; // Seconds per Sample
///
/// // ...
/// let sample = osc.next_tri(freq, israte);
/// // ...
///```
#[inline]
pub fn next_tri(&mut self, freq: f32, israte: f32) -> f32 {
let phase_inc = freq * israte;
@ -1269,6 +1337,22 @@ impl PolyBlepOscillator {
s * 4.0
}
/// Creates the next sample of a sawtooth wave.
///
/// * `freq` - The frequency in Hz.
/// * `israte` - The inverse sampling rate, or seconds per sample as in eg. `1.0 / 44100.0`.
///```
/// use HexoDSP::dsp::helpers::{PolyBlepOscillator, rand_01};
///
/// let mut osc = PolyBlepOscillator::new(rand_01() * 0.25);
///
/// let freq = 440.0; // Hz
/// let israte = 1.0 / 44100.0; // Seconds per Sample
///
/// // ...
/// let sample = osc.next_saw(freq, israte);
/// // ...
///```
#[inline]
pub fn next_saw(&mut self, freq: f32, israte: f32) -> f32 {
let phase_inc = freq * israte;
@ -1282,6 +1366,27 @@ impl PolyBlepOscillator {
s
}
/// Creates the next sample of a pulse wave.
/// In comparison to [PolyBlepOscillator::next_pulse_no_dc] this
/// version is DC compensated, so that you may add multiple different
/// pulse oscillators for a unison effect without too big DC issues.
///
/// * `freq` - The frequency in Hz.
/// * `israte` - The inverse sampling rate, or seconds per sample as in eg. `1.0 / 44100.0`.
/// * `pw` - The pulse width. Use the value 0.0 for a square wave.
///```
/// use HexoDSP::dsp::helpers::{PolyBlepOscillator, rand_01};
///
/// let mut osc = PolyBlepOscillator::new(rand_01() * 0.25);
///
/// let freq = 440.0; // Hz
/// let israte = 1.0 / 44100.0; // Seconds per Sample
/// let pw = 0.0; // 0.0 is a square wave.
///
/// // ...
/// let sample = osc.next_pulse(freq, israte);
/// // ...
///```
#[inline]
pub fn next_pulse(&mut self, freq: f32, israte: f32, pw: f32) -> f32 {
let phase_inc = freq * israte;
@ -1305,6 +1410,27 @@ impl PolyBlepOscillator {
s
}
/// Creates the next sample of a pulse wave.
/// In comparison to [PolyBlepOscillator::next_pulse] this
/// version is not DC compensated. So be careful when adding multiple
/// of this or generally using it in an audio context.
///
/// * `freq` - The frequency in Hz.
/// * `israte` - The inverse sampling rate, or seconds per sample as in eg. `1.0 / 44100.0`.
/// * `pw` - The pulse width. Use the value 0.0 for a square wave.
///```
/// use HexoDSP::dsp::helpers::{PolyBlepOscillator, rand_01};
///
/// let mut osc = PolyBlepOscillator::new(rand_01() * 0.25);
///
/// let freq = 440.0; // Hz
/// let israte = 1.0 / 44100.0; // Seconds per Sample
/// let pw = 0.0; // 0.0 is a square wave.
///
/// // ...
/// let sample = osc.next_pulse_no_dc(freq, israte, pw);
/// // ...
///```
#[inline]
pub fn next_pulse_no_dc(&mut self, freq: f32, israte: f32, pw: f32) -> f32 {
let phase_inc = freq * israte;