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// Augmented Audio: Audio libraries and applications
// Copyright (c) 2022 Pedro Tacla Yamada
//
// The MIT License (MIT)
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//!
//! Very simple implementation of an oscillator.
//!
//! # Examples
//! ## Sine oscillator
//! ```
//! let sample_rate = 44100.0;
//! let mut osc = augmented_oscillator::Oscillator::sine(sample_rate);
//! osc.set_frequency(40.0); // set freq. in Hz
//! let _sample = osc.next_sample(); // tick the oscillator forward
//! ```
//!
//! ## Wave-table oscillator
//! ```
//! use augmented_oscillator::{Oscillator, wavetable::WaveTableOscillator};
//!
//! let sample_rate = 44100.0;
//! // let mut osc = WaveTableOscillator::new(vec![/* your wave table data */]);
//! // You can either ^^^^ provide your own table (and update it at runtime) or generate a table
//! // of a certain length (100 sample here) from a function oscillator
//! let mut osc = WaveTableOscillator::from_oscillator(Oscillator::sine(sample_rate), 100);
//! osc.set_frequency(40.0); // set freq. in Hz
//! let _sample = osc.next_sample(); // tick the oscillator forward
//! ```
//!
//! ## Custom oscillator generator function
//! ```
//! let sample_rate = 44100.0;
//! let mut osc = augmented_oscillator::Oscillator::new_with_sample_rate(
//! sample_rate,
//! move |phase: f32| phase.sin()
//! );
//! osc.set_frequency(40.0); // set freq. in Hz
//! let _sample = osc.next_sample(); // tick the oscillator forward
//! ```
pub mod generators;
pub mod wavetable;
#[cfg(test)]
mod test_utils;
/// Calculate the phase step increment between samples.
///
/// This is the fraction of a period which will go through each sample tick
pub fn get_phase_step(sample_rate: f32, frequency: f32) -> f32 {
frequency / sample_rate
}
#[derive(Clone)]
pub struct Oscillator<T> {
/// Current phase of the oscillator
phase: f32,
phase_step: f32,
/// A function from `phase` to `sample`
generator_fn: fn(T) -> T,
/// The sample rate to output with
sample_rate: f32,
/// The oscillator frequency
frequency: f32,
}
impl Oscillator<f32> {
/// Construct a sine generator
pub fn sine(sample_rate: f32) -> Oscillator<f32> {
Oscillator::new_with_sample_rate(sample_rate, generators::sine_generator)
}
}
impl<T> Oscillator<T> {
/// Construct a new oscillator with a given sample rate
pub fn new_with_sample_rate(sample_rate: f32, generator_fn: fn(T) -> T) -> Self {
let frequency = 440.;
let phase_step = get_phase_step(sample_rate, frequency);
Oscillator {
sample_rate,
generator_fn,
frequency,
phase: 0.,
phase_step,
}
}
/// Construct an oscillator with `44.1Hz` default sample rate
pub fn new(generator_fn: fn(T) -> T) -> Self {
Oscillator::new_with_sample_rate(44100., generator_fn)
}
}
impl<T> Oscillator<T> {
/// Set the generator function
pub fn set_generator(&mut self, generator_fn: fn(T) -> T) {
self.generator_fn = generator_fn;
}
}
impl<T> Oscillator<T> {
/// Set the sample rate
pub fn set_sample_rate(&mut self, sample_rate: f32) {
self.sample_rate = sample_rate;
self.phase_step = get_phase_step(self.sample_rate, self.frequency);
}
}
impl<T> Oscillator<T> {
/// Get the oscillator frequency
pub fn get_frequency(&self) -> f32 {
self.frequency
}
/// Set the oscillator frequency
pub fn set_frequency(&mut self, frequency: f32) {
if (frequency - self.frequency).abs() < f32::EPSILON {
return;
}
self.frequency = frequency;
self.phase_step = get_phase_step(self.sample_rate, self.frequency);
}
}
impl<T> Oscillator<T>
where
T: From<f32>,
{
/// Process a single sample & update the oscillator phase.
pub fn next_sample(&mut self) -> T {
let result = self.get();
self.tick();
result
}
pub fn tick_n(&mut self, n: f32) {
self.phase += n * self.phase_step;
if self.phase > 1.0 {
self.phase -= 1.0;
}
}
pub fn tick(&mut self) {
self.phase += self.phase_step;
if self.phase > 1.0 {
self.phase -= 1.0;
}
}
pub fn value_for_phase(&self, phase: T) -> T {
(self.generator_fn)(phase)
}
pub fn get(&self) -> T {
// User provided function from phase to a sample
(self.generator_fn)(T::from(self.phase))
}
/// Return the current phase as a number between 0-1
pub fn phase(&self) -> f32 {
self.phase
}
}
#[cfg(test)]
mod test {
use crate::test_utils::generate_plot;
use super::*;
static DEFAULT_SAMPLE_RATE: f32 = 44100.0;
#[test]
fn test_generate_plots() {
let root_path = format!("{}/src/lib.rs", env!("CARGO_MANIFEST_DIR"));
let mut oscillator = Oscillator::sine(DEFAULT_SAMPLE_RATE);
oscillator.set_frequency(440.0);
generate_plot(&root_path, || oscillator.next_sample(), "sine-wave");
let mut oscillator =
Oscillator::new_with_sample_rate(DEFAULT_SAMPLE_RATE, generators::square_generator);
oscillator.set_frequency(440.0);
generate_plot(&root_path, || oscillator.next_sample(), "square-wave");
let mut oscillator =
Oscillator::new_with_sample_rate(DEFAULT_SAMPLE_RATE, generators::saw_generator);
oscillator.set_frequency(440.0);
generate_plot(&root_path, || oscillator.next_sample(), "saw-wave");
}
}