Struct PolyBlepOscillator

Source

pub struct PolyBlepOscillator { /* private fields */ }

Expand description

This is a band-limited oscillator based on the PolyBlep technique.

NOTE: You need to call crate::init_cos_tab.

Here is a quick example on how to use it:

 use synfx_dsp::{PolyBlepOscillator, rand_01, init_cos_tab};
 init_cos_tab();

 // 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

 let mut block_of_samples = [0.0; 128];
 // 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)
        }
 }

Implementations§

Source §

impl PolyBlepOscillator

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pub fn new(init_phase: f32) -> Self

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 synfx_dsp::*;

 let mut osc = PolyBlepOscillator::new(rand_01() * 0.25);

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pub fn reset(&mut self)

Reset the internal state of the oscillator as if you just called PolyBlepOscillator::new.

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pub fn next_sin(&mut self, freq: f32, israte: f32) -> f32

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 synfx_dsp::*;

 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);
 // ...

Source

pub fn next_tri(&mut self, freq: f32, israte: f32) -> 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 synfx_dsp::*;

 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);
 // ...

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pub fn next_saw(&mut self, freq: f32, israte: f32) -> f32

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 synfx_dsp::*;

 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);
 // ...

Source

pub fn next_pulse(&mut self, freq: f32, israte: f32, pw: f32) -> f32

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 synfx_dsp::*;

 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, pw);
 // ...

Source

pub fn next_pulse_no_dc(&mut self, freq: f32, israte: f32, pw: f32) -> f32

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 synfx_dsp::*;

 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);
 // ...