Factored out the filter implementations
This commit is contained in:
Weird Constructor
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3d099f884c
commit
d1f7cc9a4d
2 changed files with 60 additions and 58 deletions
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@ -705,6 +705,32 @@ impl Comb {
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}
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}
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// one pole lp from valley rack free:
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// https://github.com/ValleyAudio/ValleyRackFree/blob/v1.0/src/Common/DSP/OnePoleFilters.cpp
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#[inline]
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pub fn process_1pole_lowpass(input: f64, freq: f64, israte: f64, z: &mut f64) -> f64 {
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let b = (-std::f64::consts::TAU * freq * israte).exp();
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let a = 1.0 - b;
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*z = a * input + *z * b;
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*z
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}
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// one pole from:
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// http://www.willpirkle.com/Downloads/AN-4VirtualAnalogFilters.pdf
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// (page 5)
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#[inline]
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pub fn process_1pole_tpt_lowpass(input: f64, freq: f64, israte: f64, z: &mut f64) -> f64 {
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let g = (std::f64::consts::PI * freq * israte).tan();
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let a1 = g / (1.0 + g);
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let v1 = a1 * (input - *z);
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let v2 = v1 + *z;
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*z = v2 + v1;
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// let (m0, m1) = (0.0, 1.0);
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// (m0 * input + m1 * v2) as f32);
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v2
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}
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// translated from Odin 2 Synthesizer Plugin
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// Copyright (C) 2020 TheWaveWarden
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@ -747,6 +773,8 @@ impl DCBlockFilter {
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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@ -4,15 +4,16 @@
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use crate::nodes::{NodeAudioContext, NodeExecContext};
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use crate::dsp::{NodeId, SAtom, ProcBuf, DspNode, LedPhaseVals, NodeContext};
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use crate::dsp::helpers::{process_1pole_lowpass, process_1pole_tpt_lowpass};
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#[macro_export]
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macro_rules! fa_sfilter_type { ($formatter: expr, $v: expr, $denorm_v: expr) => { {
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let s =
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match ($v.round() as usize) {
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0 => "LPDat(1p)",
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1 => "LPSVF(1p)",
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2 => "LPDAFX(1p)",
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3 => "RC",
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0 => "LP(1p)",
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1 => "LP(1p,TPT)",
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2 => "HP(1p)",
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3 => "HP(1p,TPT)",
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_ => "?",
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};
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write!($formatter, "{}", s)
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@ -84,14 +85,10 @@ impl DspNode for SFilter {
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0 => {
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for frame in 0..ctx.nframes() {
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let input = inp.read(frame) as f64;
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let b =
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(-std::f64::consts::TAU
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* (denorm::SFilter::freq(freq, frame) as f64)
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* self.israte).exp();
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let a = 1.0 - b;
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self.z = a * input + self.z * b;
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out.write(frame, self.z as f32);
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let freq = (denorm::SFilter::freq(freq, frame) as f64);
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out.write(frame,
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process_1pole_lowpass(input, freq, self.israte, &mut self.z)
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as f32);
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}
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},
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// one pole from:
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@ -100,54 +97,31 @@ impl DspNode for SFilter {
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1 => {
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for frame in 0..ctx.nframes() {
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let input = inp.read(frame) as f64;
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let g =
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(std::f64::consts::PI
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* (denorm::SFilter::freq(freq, frame) as f64)
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* self.israte).tan();
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let a1 = g / (1.0 + g);
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let v1 = a1 * (input - self.z);
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let v2 = v1 + self.z;
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self.z = v2 + v1;
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let (m0, m1) = (0.0, 1.0);
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out.write(frame, (m0 * input + m1 * v2) as f32);
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}
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},
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// from DAFX by will pirkle:
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2 => {
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for frame in 0..ctx.nframes() {
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let input = inp.read(frame) as f64;
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let o =
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(-std::f64::consts::TAU
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* (denorm::SFilter::freq(freq, frame) as f64)
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* self.israte).cos();
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let y = 2.0 - o;
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let b = (y * y - 1.0).sqrt() - y;
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let a = 1.0 + b;
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self.z = a * input - b * self.z;
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out.write(frame, self.z as f32);
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}
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},
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// From https://en.wikipedia.org/wiki/RC_circuit
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3 => {
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for frame in 0..ctx.nframes() {
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let input = inp.read(frame) as f64;
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let c =
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2.0
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/ (std::f64::consts::TAU
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* (denorm::SFilter::freq(freq, frame) as f64)
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* self.israte);
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let y = (input + self.z - self.y * (1.0 - c)) / (1.0 + c);
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self.z = input;
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self.y = y;
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// highpass: self.z - self.y
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out.write(frame, y as f32);
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let freq = (denorm::SFilter::freq(freq, frame) as f64);
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out.write(frame,
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process_1pole_tpt_lowpass(input, freq, self.israte, &mut self.z)
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as f32);
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}
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},
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// // From https://en.wikipedia.org/wiki/RC_circuit
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// // has the same output as the SVF variant, takes the same amount of time.
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// 3 => {
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// for frame in 0..ctx.nframes() {
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// let input = inp.read(frame) as f64;
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// let c =
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// 2.0
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// / (std::f64::consts::TAU
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// * (denorm::SFilter::freq(freq, frame) as f64)
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// * self.israte);
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//
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// let y = (input + self.z - self.y * (1.0 - c)) / (1.0 + c);
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// self.z = input;
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// self.y = y;
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//
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// // highpass: self.z - self.y
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// out.write(frame, y as f32);
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// }
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// },
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_ => {},
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}
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}
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