tuxmain/HexoDSP
1
0
Fork 0
Code Issues Pull requests Packages Projects Releases Wiki Activity
HexoDSP/src/dsp/helpers.rs
Weird Constructor 7a46c38a00 use f32 instead of f64 for filtering
2021-07-15 06:28:44 +02:00

1108 lines
30 KiB
Rust
Raw Blame History

// Copyright (c) 2021 Weird Constructor <weirdconstructor@gmail.com>
// This is a part of HexoDSP. Released under (A)GPLv3 or any later.
// See README.md and COPYING for details.
/// Logarithmic table size of the table in [fast_cos] / [fast_sin].
static FAST_COS_TAB_LOG2_SIZE : usize = 9;
/// Table size of the table in [fast_cos] / [fast_sin].
static FAST_COS_TAB_SIZE : usize = 1 << FAST_COS_TAB_LOG2_SIZE; // =512
/// The wave table of [fast_cos] / [fast_sin].
static mut FAST_COS_TAB : [f32; 513] = [0.0; 513];
/// Initializes the cosine wave table for [fast_cos] and [fast_sin].
pub fn init_cos_tab() {
for i in 0..(FAST_COS_TAB_SIZE+1) {
let phase : f32 =
(i as f32)
* ((std::f32::consts::TAU)
/ (FAST_COS_TAB_SIZE as f32));
unsafe {
// XXX: note: mutable statics can be mutated by multiple
// threads: aliasing violations or data races
// will cause undefined behavior
FAST_COS_TAB[i] = phase.cos();
}
}
}
/// Internal phase increment/scaling for [fast_cos].
const PHASE_SCALE : f32 = 1.0_f32 / (std::f32::consts::TAU);
/// A faster implementation of cosine. It's not that much faster than
/// Rust's built in cosine function. But YMMV.
///
/// Don't forget to call [init_cos_tab] before using this!
///
///```
/// use hexodsp::dsp::helpers::*;
/// init_cos_tab(); // Once on process initialization.
///
/// // ...
/// assert!((fast_cos(std::f32::consts::PI) - -1.0).abs() < 0.001);
///```
pub fn fast_cos(mut x: f32) -> f32 {
x = x.abs(); // cosine is symmetrical around 0, let's get rid of negative values
// normalize range from 0..2PI to 1..2
let phase = x * PHASE_SCALE;
let index = FAST_COS_TAB_SIZE as f32 * phase;
let fract = index.fract();
let index = index.floor() as usize;
unsafe {
// XXX: note: mutable statics can be mutated by multiple
// threads: aliasing violations or data races
// will cause undefined behavior
let left = FAST_COS_TAB[index as usize];
let right = FAST_COS_TAB[index as usize + 1];
return left + (right - left) * fract;
}
}
/// A faster implementation of sine. It's not that much faster than
/// Rust's built in sine function. But YMMV.
///
/// Don't forget to call [init_cos_tab] before using this!
///
///```
/// use hexodsp::dsp::helpers::*;
/// init_cos_tab(); // Once on process initialization.
///
/// // ...
/// assert!((fast_sin(0.5 * std::f32::consts::PI) - 1.0).abs() < 0.001);
///```
pub fn fast_sin(x: f32) -> f32 {
fast_cos(x - (std::f32::consts::PI / 2.0))
}
/// A wavetable filled entirely with white noise.
/// Don't forget to call [init_white_noise_tab] before using it.
static mut WHITE_NOISE_TAB: [f64; 1024] = [0.0; 1024];
/// Initializes [WHITE_NOISE_TAB].
pub fn init_white_noise_tab() {
let mut rng = RandGen::new();
unsafe {
for i in 0..WHITE_NOISE_TAB.len() {
WHITE_NOISE_TAB[i as usize] = rng.next_open01();
}
}
}
#[derive(Debug, Copy, Clone, PartialEq)]
/// Random number generator based on xoroshiro128.
/// Requires two internal state variables. You may prefer [SplitMix64] or [Rng].
pub struct RandGen {
r: [u64; 2],
}
// Taken from xoroshiro128 crate under MIT License
// Implemented by Matthew Scharley (Copyright 2016)
// https://github.com/mscharley/rust-xoroshiro128
/// Given the mutable `state` generates the next pseudo random number.
pub fn next_xoroshiro128(state: &mut [u64; 2]) -> u64 {
let s0: u64 = state[0];
let mut s1: u64 = state[1];
let result: u64 = s0.wrapping_add(s1);
s1 ^= s0;
state[0] = s0.rotate_left(55) ^ s1 ^ (s1 << 14); // a, b
state[1] = s1.rotate_left(36); // c
result
}
// Taken from rand::distributions
// Licensed under the Apache License, Version 2.0
// Copyright 2018 Developers of the Rand project.
/// Maps any `u64` to a `f64` in the open interval `[0.0, 1.0)`.
pub fn u64_to_open01(u: u64) -> f64 {
use core::f64::EPSILON;
let float_size = std::mem::size_of::<f64>() as u32 * 8;
let fraction = u >> (float_size - 52);
let exponent_bits: u64 = (1023 as u64) << 52;
f64::from_bits(fraction | exponent_bits) - (1.0 - EPSILON / 2.0)
}
impl RandGen {
pub fn new() -> Self {
RandGen {
r: [0x193a6754a8a7d469, 0x97830e05113ba7bb],
}
}
/// Next random unsigned 64bit integer.
pub fn next(&mut self) -> u64 {
next_xoroshiro128(&mut self.r)
}
/// Next random float between `[0.0, 1.0)`.
pub fn next_open01(&mut self) -> f64 {
u64_to_open01(self.next())
}
}
#[derive(Debug, Copy, Clone)]
/// Random number generator based on [SplitMix64].
/// Requires two internal state variables. You may prefer [SplitMix64] or [Rng].
pub struct Rng {
sm: SplitMix64,
}
impl Rng {
pub fn new() -> Self {
Self { sm: SplitMix64::new(0x193a67f4a8a6d769) }
}
pub fn seed(&mut self, seed: u64) {
println!("SEED {}", seed);
self.sm = SplitMix64::new(seed);
}
#[inline]
pub fn next(&mut self) -> f32 {
self.sm.next_open01() as f32
}
}
// Copyright 2018 Developers of the Rand project.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//- splitmix64 (http://xoroshiro.di.unimi.it/splitmix64.c)
//
/// A splitmix64 random number generator.
///
/// The splitmix algorithm is not suitable for cryptographic purposes, but is
/// very fast and has a 64 bit state.
///
/// The algorithm used here is translated from [the `splitmix64.c`
/// reference source code](http://xoshiro.di.unimi.it/splitmix64.c) by
/// Sebastiano Vigna. For `next_u32`, a more efficient mixing function taken
/// from [`dsiutils`](http://dsiutils.di.unimi.it/) is used.
#[derive(Debug, Copy, Clone)]
pub struct SplitMix64(pub u64);
/// Internal random constant for [SplitMix64].
const PHI: u64 = 0x9e3779b97f4a7c15;
impl SplitMix64 {
pub fn new(seed: u64) -> Self { Self(seed) }
pub fn new_from_i64(seed: i64) -> Self {
Self::new(u64::from_be_bytes(seed.to_be_bytes()))
}
#[inline]
pub fn next_u64(&mut self) -> u64 {
self.0 = self.0.wrapping_add(PHI);
let mut z = self.0;
z = (z ^ (z >> 30)).wrapping_mul(0xbf58476d1ce4e5b9);
z = (z ^ (z >> 27)).wrapping_mul(0x94d049bb133111eb);
z ^ (z >> 31)
}
#[inline]
pub fn next_i64(&mut self) -> i64 {
i64::from_be_bytes(
self.next_u64().to_be_bytes())
}
#[inline]
pub fn next_open01(&mut self) -> f64 {
u64_to_open01(self.next_u64())
}
}
#[inline]
pub fn crossfade(v1: f32, v2: f32, mix: f32) -> f32 {
v1 * (1.0 - mix) + v2 * mix
}
#[inline]
pub fn clamp(f: f32, min: f32, max: f32) -> f32 {
if f < min { min }
else if f > max { max }
else { f }
}
pub fn square_135(phase: f32) -> f32 {
fast_sin(phase)
+ fast_sin(phase * 3.0) / 3.0
+ fast_sin(phase * 5.0) / 5.0
}
pub fn square_35(phase: f32) -> f32 {
fast_sin(phase * 3.0) / 3.0
+ fast_sin(phase * 5.0) / 5.0
}
// note: MIDI note value?
pub fn note_to_freq(note: f32) -> f32 {
440.0 * (2.0_f32).powf((note - 69.0) / 12.0)
}
// Ported from LMMS under GPLv2
// * DspEffectLibrary.h - library with template-based inline-effects
// * Copyright (c) 2006-2014 Tobias Doerffel <tobydox/at/users.sourceforge.net>
//
/// Signal distortion
/// ```text
/// gain: 0.1 - 5.0 default = 1.0
/// threshold: 0.0 - 100.0 default = 0.8
/// i: signal
/// ```
pub fn f_distort(gain: f32, threshold: f32, i: f32) -> f32 {
gain * (
i * ( i.abs() + threshold )
/ ( i * i + (threshold - 1.0) * i.abs() + 1.0 ))
}
// Ported from LMMS under GPLv2
// * DspEffectLibrary.h - library with template-based inline-effects
// * Copyright (c) 2006-2014 Tobias Doerffel <tobydox/at/users.sourceforge.net>
//
/// Foldback Signal distortion
/// ```text
/// gain: 0.1 - 5.0 default = 1.0
/// threshold: 0.0 - 100.0 default = 0.8
/// i: signal
/// ```
pub fn f_fold_distort(gain: f32, threshold: f32, i: f32) -> f32 {
if i >= threshold || i < -threshold {
gain
* ((
((i - threshold) % threshold * 4.0).abs()
- threshold * 2.0).abs()
- threshold)
} else {
gain * i
}
}
pub fn lerp(x: f32, a: f32, b: f32) -> f32 {
(a * (1.0 - x)) + (b * x)
}
pub fn lerp64(x: f64, a: f64, b: f64) -> f64 {
(a * (1.0 - x)) + (b * x)
}
pub fn p2range(x: f32, a: f32, b: f32) -> f32 {
lerp(x, a, b)
}
pub fn p2range_exp(x: f32, a: f32, b: f32) -> f32 {
let x = x * x;
(a * (1.0 - x)) + (b * x)
}
pub fn p2range_exp4(x: f32, a: f32, b: f32) -> f32 {
let x = x * x * x * x;
(a * (1.0 - x)) + (b * x)
}
pub fn range2p(v: f32, a: f32, b: f32) -> f32 {
((v - a) / (b - a)).abs()
}
pub fn range2p_exp(v: f32, a: f32, b: f32) -> f32 {
(((v - a) / (b - a)).abs()).sqrt()
}
pub fn range2p_exp4(v: f32, a: f32, b: f32) -> f32 {
(((v - a) / (b - a)).abs()).sqrt().sqrt()
}
/// ```text
/// gain: 24.0 - -90.0 default = 0.0
/// ```
pub fn gain2coef(gain: f32) -> f32 {
if gain > -90.0 {
10.0_f32.powf(gain * 0.05)
} else {
0.0
}
}
// quickerTanh / quickerTanh64 credits to mopo synthesis library:
// Under GPLv3 or any later.
// Little IO <littleioaudio@gmail.com>
// Matt Tytel <matthewtytel@gmail.com>
pub fn quicker_tanh64(v: f64) -> f64 {
let square = v * v;
v / (1.0 + square / (3.0 + square / 5.0))
}
pub fn quicker_tanh(v: f32) -> f32 {
let square = v * v;
v / (1.0 + square / (3.0 + square / 5.0))
}
// quickTanh / quickTanh64 credits to mopo synthesis library:
// Under GPLv3 or any later.
// Little IO <littleioaudio@gmail.com>
// Matt Tytel <matthewtytel@gmail.com>
pub fn quick_tanh64(v: f64) -> f64 {
let abs_v = v.abs();
let square = v * v;
let num =
v * (2.45550750702956
+ 2.45550750702956 * abs_v
+ square * (0.893229853513558
+ 0.821226666969744 * abs_v));
let den =
2.44506634652299
+ (2.44506634652299 + square)
* (v + 0.814642734961073 * v * abs_v).abs();
num / den
}
pub fn quick_tanh(v: f32) -> f32 {
let abs_v = v.abs();
let square = v * v;
let num =
v * (2.45550750702956
+ 2.45550750702956 * abs_v
+ square * (0.893229853513558
+ 0.821226666969744 * abs_v));
let den =
2.44506634652299
+ (2.44506634652299 + square)
* (v + 0.814642734961073 * v * abs_v).abs();
num / den
}
/// A helper function for exponential envelopes.
/// It's a bit faster than calling the `pow` function of Rust.
///
/// * `x` the input value
/// * `v' the shape value.
/// Which is linear at `0.5`, the forth root of `x` at `1.0` and x to the power
/// of 4 at `0.0`. You can vary `v` as you like.
///
///```
/// use hexodsp::dsp::helpers::*;
///
/// assert!(((sqrt4_to_pow4(0.25, 0.0) - 0.25_f32 * 0.25 * 0.25 * 0.25)
/// .abs() - 1.0)
/// < 0.0001);
///
/// assert!(((sqrt4_to_pow4(0.25, 1.0) - (0.25_f32).sqrt().sqrt())
/// .abs() - 1.0)
/// < 0.0001);
///
/// assert!(((sqrt4_to_pow4(0.25, 0.5) - 0.25_f32).abs() - 1.0) < 0.0001);
///```
#[inline]
pub fn sqrt4_to_pow4(x: f32, v: f32) -> f32 {
if v > 0.75 {
let xsq1 = x.sqrt();
let xsq = xsq1.sqrt();
let v = (v - 0.75) * 4.0;
xsq1 * (1.0 - v) + xsq * v
} else if v > 0.5 {
let xsq = x.sqrt();
let v = (v - 0.5) * 4.0;
x * (1.0 - v) + xsq * v
} else if v > 0.25 {
let xx = x * x;
let v = (v - 0.25) * 4.0;
x * v + xx * (1.0 - v)
} else {
let xx = x * x;
let xxxx = xx * xx;
let v = v * 4.0;
xx * v + xxxx * (1.0 - v)
}
}
/// A-100 Eurorack states, that a trigger is usually 2-10 milliseconds.
const TRIG_SIGNAL_LENGTH_MS : f32 = 2.0;
#[derive(Debug, Clone, Copy)]
pub struct TrigSignal {
length: u32,
scount: u32,
}
impl TrigSignal {
pub fn new() -> Self {
Self {
length: ((44100.0 * TRIG_SIGNAL_LENGTH_MS) / 1000.0).ceil() as u32,
scount: 0,
}
}
pub fn reset(&mut self) {
self.scount = 0;
}
pub fn set_sample_rate(&mut self, srate: f32) {
self.length = ((srate * TRIG_SIGNAL_LENGTH_MS) / 1000.0).ceil() as u32;
self.scount = 0;
}
#[inline]
pub fn trigger(&mut self) { self.scount = self.length; }
#[inline]
pub fn next(&mut self) -> f32 {
if self.scount > 0 {
self.scount -= 1;
1.0
} else {
0.0
}
}
}
impl Default for TrigSignal {
fn default() -> Self { Self::new() }
}
#[derive(Debug, Clone, Copy)]
pub struct Trigger {
triggered: bool,
}
impl Trigger {
pub fn new() -> Self {
Self {
triggered: false,
}
}
#[inline]
pub fn reset(&mut self) {
self.triggered = false;
}
#[inline]
pub fn check_trigger(&mut self, input: f32) -> bool {
if self.triggered {
if input <= 0.25 {
self.triggered = false;
}
false
} else if input > 0.75 {
self.triggered = true;
true
} else {
false
}
}
}
#[derive(Debug, Clone, Copy)]
pub struct TriggerPhaseClock {
clock_phase: f64,
clock_inc: f64,
prev_trigger: bool,
clock_samples: u32,
}
impl TriggerPhaseClock {
pub fn new() -> Self {
Self {
clock_phase: 0.0,
clock_inc: 0.0,
prev_trigger: true,
clock_samples: 0,
}
}
#[inline]
pub fn reset(&mut self) {
self.clock_samples = 0;
self.clock_inc = 0.0;
self.prev_trigger = true;
self.clock_samples = 0;
}
#[inline]
pub fn sync(&mut self) {
self.clock_phase = 0.0;
}
#[inline]
pub fn next_phase(&mut self, clock_limit: f64, trigger_in: f32) -> f64 {
if self.prev_trigger {
if trigger_in <= 0.25 {
self.prev_trigger = false;
}
} else if trigger_in > 0.75 {
self.prev_trigger = true;
if self.clock_samples > 0 {
self.clock_inc =
1.0 / (self.clock_samples as f64);
}
self.clock_samples = 0;
}
self.clock_samples += 1;
self.clock_phase += self.clock_inc;
self.clock_phase = self.clock_phase % clock_limit;
self.clock_phase
}
}
#[derive(Debug, Clone, Copy)]
pub struct TriggerSampleClock {
prev_trigger: bool,
clock_samples: u32,
counter: u32,
}
impl TriggerSampleClock {
pub fn new() -> Self {
Self {
prev_trigger: true,
clock_samples: 0,
counter: 0,
}
}
#[inline]
pub fn reset(&mut self) {
self.clock_samples = 0;
self.counter = 0;
}
#[inline]
pub fn next(&mut self, trigger_in: f32) -> u32 {
if self.prev_trigger {
if trigger_in <= 0.25 {
self.prev_trigger = false;
}
} else if trigger_in > 0.75 {
self.prev_trigger = true;
self.clock_samples = self.counter;
self.counter = 0;
}
self.counter += 1;
self.clock_samples
}
}
/// Default size of the delay buffer: 5 seconds at 8 times 48kHz
const DEFAULT_DELAY_BUFFER_SAMPLES : usize = 8 * 48000 * 5;
#[derive(Debug, Clone)]
pub struct DelayBuffer {
data: Vec<f32>,
wr: usize,
srate: f32,
}
impl DelayBuffer {
pub fn new() -> Self {
Self {
data: vec![0.0; DEFAULT_DELAY_BUFFER_SAMPLES],
wr: 0,
srate: 44100.0,
}
}
pub fn new_with_size(size: usize) -> Self {
Self {
data: vec![0.0; size],
wr: 0,
srate: 44100.0,
}
}
pub fn set_sample_rate(&mut self, srate: f32) {
self.srate = srate;
}
pub fn reset(&mut self) {
self.data.fill(0.0);
self.wr = 0;
}
/// Feed one sample into the delay line and increment the write pointer.
/// Please note: For sample accurate feedback you need to retrieve the
/// output of the delay line before feeding in a new signal.
#[inline]
pub fn feed(&mut self, input: f32) {
self.data[self.wr] = input;
self.wr = (self.wr + 1) % self.data.len();
}
#[inline]
pub fn cubic_interpolate_at(&self, delay_time: f32) -> f32 {
let data = &self.data[..];
let len = data.len();
let s_offs = (delay_time * self.srate) / 1000.0;
let offs = s_offs.floor() as usize % len;
let fract = s_offs.fract();
let i = (self.wr + len) - offs;
// Hermite interpolation, take from
// https://github.com/eric-wood/delay/blob/main/src/delay.rs#L52
//
// Thanks go to Eric Wood!
//
// For the interpolation code:
// MIT License, Copyright (c) 2021 Eric Wood
let xm1 = data[(i - 1) % len];
let x0 = data[i % len];
let x1 = data[(i + 1) % len];
let x2 = data[(i + 2) % len];
let c = (x1 - xm1) * 0.5;
let v = x0 - x1;
let w = c + v;
let a = w + v + (x2 - x0) * 0.5;
let b_neg = w + a;
let fract = fract as f32;
(((a * fract) - b_neg) * fract + c) * fract + x0
}
#[inline]
pub fn nearest_at(&self, delay_time: f32) -> f32 {
let len = self.data.len();
let offs = (delay_time * self.srate).floor() as usize % len;
let idx = ((self.wr + len) - offs) % len;
self.data[idx]
}
#[inline]
pub fn at(&self, delay_sample_count: usize) -> f32 {
let len = self.data.len();
let idx = ((self.wr + len) - delay_sample_count) % len;
self.data[idx]
}
}
/// Default size of the delay buffer: 1 seconds at 8 times 48kHz
const DEFAULT_ALLPASS_COMB_SAMPLES : usize = 8 * 48000;
#[derive(Debug, Clone)]
pub struct AllPass {
delay: DelayBuffer,
}
impl AllPass {
pub fn new() -> Self {
Self {
delay: DelayBuffer::new_with_size(DEFAULT_ALLPASS_COMB_SAMPLES),
}
}
pub fn set_sample_rate(&mut self, srate: f32) {
self.delay.set_sample_rate(srate);
}
pub fn reset(&mut self) {
self.delay.reset();
}
#[inline]
pub fn next(&mut self, time: f32, g: f32, v: f32) -> f32 {
let s = self.delay.cubic_interpolate_at(time);
self.delay.feed(v + s * g);
s + -1.0 * g * v
}
}
#[derive(Debug, Clone)]
pub struct Comb {
delay: DelayBuffer,
}
impl Comb {
pub fn new() -> Self {
Self {
delay: DelayBuffer::new_with_size(DEFAULT_ALLPASS_COMB_SAMPLES),
}
}
pub fn set_sample_rate(&mut self, srate: f32) {
self.delay.set_sample_rate(srate);
}
pub fn reset(&mut self) {
self.delay.reset();
}
#[inline]
pub fn next_feedback(&mut self, time: f32, g: f32, v: f32) -> f32 {
let s = self.delay.cubic_interpolate_at(time);
self.delay.feed(v + s * g);
v
}
#[inline]
pub fn next_feedforward(&mut self, time: f32, g: f32, v: f32) -> f32 {
let s = self.delay.cubic_interpolate_at(time);
self.delay.feed(v);
v + s * g
}
}
// one pole lp from valley rack free:
// https://github.com/ValleyAudio/ValleyRackFree/blob/v1.0/src/Common/DSP/OnePoleFilters.cpp
#[inline]
/// Process a very simple one pole 6dB low pass filter.
/// Useful in various applications, from usage in a synthesizer to
/// damping stuff in a reverb/delay.
///
/// * `input` - Input sample
/// * `freq` - Frequency between 1.0 and 22000.0Hz
/// * `israte` - 1.0 / samplerate
/// * `z` - The internal one sample buffer of the filter.
///
///```
/// use hexodsp::dsp::helpers::*;
///
/// let samples = vec![0.0; 44100];
/// let mut z = 0.0;
/// let mut freq = 1000.0;
///
/// for s in samples.iter() {
/// let s_out =
/// process_1pole_lowpass(*s, freq, 1.0 / 44100.0, &mut z);
/// // ... do something with the result here.
/// }
///```
pub fn process_1pole_lowpass(input: f32, freq: f32, israte: f32, z: &mut f32) -> f32 {
let b = (-std::f32::consts::TAU * freq * israte).exp();
let a = 1.0 - b;
*z = a * input + *z * b;
*z
}
// one pole hp from valley rack free:
// https://github.com/ValleyAudio/ValleyRackFree/blob/v1.0/src/Common/DSP/OnePoleFilters.cpp
#[inline]
/// Process a very simple one pole 6dB high pass filter.
/// Useful in various applications.
///
/// * `input` - Input sample
/// * `freq` - Frequency between 1.0 and 22000.0Hz
/// * `israte` - 1.0 / samplerate
/// * `z` - The first internal buffer of the filter.
/// * `y` - The second internal buffer of the filter.
///
///```
/// use hexodsp::dsp::helpers::*;
///
/// let samples = vec![0.0; 44100];
/// let mut z = 0.0;
/// let mut y = 0.0;
/// let mut freq = 1000.0;
///
/// for s in samples.iter() {
/// let s_out =
/// process_1pole_highpass(*s, freq, 1.0 / 44100.0, &mut z, &mut y);
/// // ... do something with the result here.
/// }
///```
pub fn process_1pole_highpass(input: f32, freq: f32, israte: f32, z: &mut f32, y: &mut f32) -> f32 {
let b = (-std::f32::consts::TAU * freq * israte).exp();
let a = (1.0 + b) / 2.0;
let v =
a * input
- a * *z
+ b * *y;
*y = v;
*z = input;
v
}
// one pole from:
// http://www.willpirkle.com/Downloads/AN-4VirtualAnalogFilters.pdf
// (page 5)
#[inline]
/// Process a very simple one pole 6dB low pass filter in TPT form.
/// Useful in various applications, from usage in a synthesizer to
/// damping stuff in a reverb/delay.
///
/// * `input` - Input sample
/// * `freq` - Frequency between 1.0 and 22000.0Hz
/// * `israte` - 1.0 / samplerate
/// * `z` - The internal one sample buffer of the filter.
///
///```
/// use hexodsp::dsp::helpers::*;
///
/// let samples = vec![0.0; 44100];
/// let mut z = 0.0;
/// let mut freq = 1000.0;
///
/// for s in samples.iter() {
/// let s_out =
/// process_1pole_tpt_highpass(*s, freq, 1.0 / 44100.0, &mut z);
/// // ... do something with the result here.
/// }
///```
pub fn process_1pole_tpt_lowpass(input: f32, freq: f32, israte: f32, z: &mut f32) -> f32 {
let g = (std::f32::consts::PI * freq * israte).tan();
let a = g / (1.0 + g);
let v1 = a * (input - *z);
let v2 = v1 + *z;
*z = v2 + v1;
// let (m0, m1) = (0.0, 1.0);
// (m0 * input + m1 * v2) as f32);
v2
}
// one pole from:
// http://www.willpirkle.com/Downloads/AN-4VirtualAnalogFilters.pdf
// (page 5)
#[inline]
/// Process a very simple one pole 6dB high pass filter in TPT form.
/// Useful in various applications.
///
/// * `input` - Input sample
/// * `freq` - Frequency between 1.0 and 22000.0Hz
/// * `israte` - 1.0 / samplerate
/// * `z` - The internal one sample buffer of the filter.
///
///```
/// use hexodsp::dsp::helpers::*;
///
/// let samples = vec![0.0; 44100];
/// let mut z = 0.0;
/// let mut freq = 1000.0;
///
/// for s in samples.iter() {
/// let s_out =
/// process_1pole_tpt_lowpass(*s, freq, 1.0 / 44100.0, &mut z);
/// // ... do something with the result here.
/// }
///```
pub fn process_1pole_tpt_highpass(input: f32, freq: f32, israte: f32, z: &mut f32) -> f32 {
let g = (std::f32::consts::PI * freq * israte).tan();
let a1 = g / (1.0 + g);
let v1 = a1 * (input - *z);
let v2 = v1 + *z;
*z = v2 + v1;
input - v2
}
/// The internal oversampling factor of [process_hal_chamberlin_svf].
const FILTER_OVERSAMPLE_HAL_CHAMBERLIN : usize = 2;
// Hal Chamberlin's State Variable (12dB/oct) filter
// https://www.earlevel.com/main/2003/03/02/the-digital-state-variable-filter/
// Inspired by SynthV1 by Rui Nuno Capela, under the terms of
// GPLv2 or any later:
/// Process a HAL Chamberlin filter with two delays/state variables.
/// The filter does internal oversampling with very simple decimation to
/// rise the stability for cutoff frequency up to 16kHz.
///
/// * `input` - Input sample.
/// * `freq` - Frequency in Hz. Please keep it inside 0.0 to 16000.0 Hz!
/// otherwise the filter becomes unstable.
/// * `res` - Resonance from 0.0 to 0.99. Resonance of 1.0 is not recommended,
/// as the filter will then oscillate itself out of control.
/// * `israte` - 1.0 divided by the sampling rate (eg. 1.0 / 44100.0).
/// * `band` - First state variable, containing the band pass result
/// after processing.
/// * `low` - Second state variable, containing the low pass result
/// after processing.
///
/// Returned are the results of the high and notch filter.
///
///```
/// use hexodsp::dsp::helpers::*;
///
/// let samples = vec![0.0; 44100];
/// let mut band = 0.0;
/// let mut low = 0.0;
/// let mut freq = 1000.0;
///
/// for s in samples.iter() {
/// let (high, notch) =
/// process_hal_chamberlin_svf(
/// *s, freq, 0.5, 1.0 / 44100.0, &mut band, &mut low);
/// // ... do something with the result here.
/// }
///```
#[inline]
pub fn process_hal_chamberlin_svf(
input: f32, freq: f32, res: f32, israte: f32, band: &mut f32, low: &mut f32)
-> (f32, f32)
{
let q = 1.0 - res;
let cutoff = 2.0 * (std::f32::consts::PI * freq * 0.5 * israte).sin();
let mut high = 0.0;
let mut notch = 0.0;
for _ in 0..FILTER_OVERSAMPLE_HAL_CHAMBERLIN {
*low += cutoff * *band;
high = input - *low - q * *band;
*band += cutoff * high;
notch = high + *low;
}
//d// println!("q={:4.2} cut={:8.3} freq={:8.1} LP={:8.3} HP={:8.3} BP={:8.3} N={:8.3}",
//d// q, cutoff, freq, *low, high, *band, notch);
(high, notch)
}
/// This function processes a Simper SVF. It's a much newer algorithm
/// for filtering and provides easy to calculate multiple outputs.
///
/// * `input` - Input sample.
/// * `freq` - Frequency in Hz.
/// otherwise the filter becomes unstable.
/// * `res` - Resonance from 0.0 to 0.99. Resonance of 1.0 is not recommended,
/// as the filter will then oscillate itself out of control.
/// * `israte` - 1.0 divided by the sampling rate (eg. 1.0 / 44100.0).
/// * `band` - First state variable, containing the band pass result
/// after processing.
/// * `low` - Second state variable, containing the low pass result
/// after processing.
///
/// This function returns the low pass, band pass and high pass signal.
/// For a notch or peak filter signal, please consult the following example:
///
///```
/// use hexodsp::dsp::helpers::*;
///
/// let samples = vec![0.0; 44100];
/// let mut ic1eq = 0.0;
/// let mut ic2eq = 0.0;
/// let mut freq = 1000.0;
///
/// for s in samples.iter() {
/// let (low, band, high) =
/// process_simper_svf(
/// *s, freq, 0.5, 1.0 / 44100.0, &mut ic1eq, &mut ic2eq);
///
/// // You can easily calculate the notch and peak results too:
/// let notch = low + high;
/// let peak = low - high;
/// // ... do something with the result here.
/// }
///```
// Simper SVF taken from baseplug (Rust crate) example svf_simper.rs:
// implemented from https://cytomic.com/files/dsp/SvfLinearTrapOptimised2.pdf
// thanks, andy!
#[inline]
pub fn process_simper_svf(
input: f32, freq: f32, res: f32, israte: f32, ic1eq: &mut f32, ic2eq: &mut f32
) -> (f32, f32, f32) {
let g = (std::f32::consts::PI * freq * israte).tan();
// XXX: the 1.989 were tuned by hand, so the resonance is more audible.
let k = 2f32 - (1.989f32 * res);
let a1 = 1.0 / (1.0 + (g * (g + k)));
let a2 = g * a1;
let a3 = g * a2;
let v3 = input - *ic2eq;
let v1 = (a1 * *ic1eq) + (a2 * v3);
let v2 = *ic2eq + (a2 * *ic1eq) + (a3 * v3);
*ic1eq = (2.0 * v1) - *ic1eq;
*ic2eq = (2.0 * v2) - *ic2eq;
// low = v2
// band = v1
// high = input - k * v1 - v2
// notch = low + high = input - k * v1
// peak = low - high = 2 * v2 - input + k * v1
// all = low + high - k * band = input - 2 * k * v1
(v2, v1, input - k * v1 - v2)
}
// translated from Odin 2 Synthesizer Plugin
// Copyright (C) 2020 TheWaveWarden
// under GPLv3 or any later
#[derive(Debug, Clone)]
pub struct DCBlockFilter {
xm1: f64,
ym1: f64,
r: f64,
}
impl DCBlockFilter {
pub fn new() -> Self {
Self {
xm1: 0.0,
ym1: 0.0,
r: 0.995,
}
}
pub fn reset(&mut self) {
self.xm1 = 0.0;
self.ym1 = 0.0;
}
pub fn set_sample_rate(&mut self, srate: f32) {
self.r = 0.995;
if srate > 90000.0 {
self.r = 0.9965;
} else if srate > 120000.0 {
self.r = 0.997;
}
}
pub fn next(&mut self, input: f32) -> f32 {
let y = input as f64 - self.xm1 + self.r * self.ym1;
self.xm1 = input as f64;
self.ym1 = y;
y as f32
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn check_range2p_exp() {
let a = p2range_exp(0.5, 1.0, 100.0);
let x = range2p_exp(a, 1.0, 100.0);
assert!((x - 0.5).abs() < std::f32::EPSILON);
}
#[test]
fn check_range2p() {
let a = p2range(0.5, 1.0, 100.0);
let x = range2p(a, 1.0, 100.0);
assert!((x - 0.5).abs() < std::f32::EPSILON);
}
}
Reference in a new issue View git blame Copy permalink