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Factored out the filter implementations

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This commit is contained in:
Weird Constructor 2021-07-10 22:40:40 +02:00
parent 3d099f884c
commit d1f7cc9a4d
2 changed files with 60 additions and 58 deletions
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28
src/dsp/helpers.rs
View file

@ -705,6 +705,32 @@ impl Comb {
}
}
// one pole lp from valley rack free:
// https://github.com/ValleyAudio/ValleyRackFree/blob/v1.0/src/Common/DSP/OnePoleFilters.cpp
#[inline]
pub fn process_1pole_lowpass(input: f64, freq: f64, israte: f64, z: &mut f64) -> f64 {
let b = (-std::f64::consts::TAU * freq * israte).exp();
let a = 1.0 - b;
*z = a * input + *z * b;
*z
}
// one pole from:
// http://www.willpirkle.com/Downloads/AN-4VirtualAnalogFilters.pdf
// (page 5)
#[inline]
pub fn process_1pole_tpt_lowpass(input: f64, freq: f64, israte: f64, z: &mut f64) -> f64 {
let g = (std::f64::consts::PI * freq * israte).tan();
let a1 = g / (1.0 + g);
let v1 = a1 * (input - *z);
let v2 = v1 + *z;
*z = v2 + v1;
// let (m0, m1) = (0.0, 1.0);
// (m0 * input + m1 * v2) as f32);
v2
}
// translated from Odin 2 Synthesizer Plugin
// Copyright (C) 2020 TheWaveWarden
@ -747,6 +773,8 @@ impl DCBlockFilter {
}
}
#[cfg(test)]
mod tests {
use super::*;

90
src/dsp/node_sfilter.rs
View file

@ -4,15 +4,16 @@
use crate::nodes::{NodeAudioContext, NodeExecContext};
use crate::dsp::{NodeId, SAtom, ProcBuf, DspNode, LedPhaseVals, NodeContext};
use crate::dsp::helpers::{process_1pole_lowpass, process_1pole_tpt_lowpass};
#[macro_export]
macro_rules! fa_sfilter_type { ($formatter: expr, $v: expr, $denorm_v: expr) => { {
let s =
match ($v.round() as usize) {
0 => "LPDat(1p)",
1 => "LPSVF(1p)",
2 => "LPDAFX(1p)",
3 => "RC",
0 => "LP(1p)",
1 => "LP(1p,TPT)",
2 => "HP(1p)",
3 => "HP(1p,TPT)",
_ => "?",
};
write!($formatter, "{}", s)
@ -84,14 +85,10 @@ impl DspNode for SFilter {
0 => {
for frame in 0..ctx.nframes() {
let input = inp.read(frame) as f64;
let b =
(-std::f64::consts::TAU
* (denorm::SFilter::freq(freq, frame) as f64)
* self.israte).exp();
let a = 1.0 - b;
self.z = a * input + self.z * b;
out.write(frame, self.z as f32);
let freq = (denorm::SFilter::freq(freq, frame) as f64);
out.write(frame,
process_1pole_lowpass(input, freq, self.israte, &mut self.z)
as f32);
}
},
// one pole from:
@ -100,54 +97,31 @@ impl DspNode for SFilter {
1 => {
for frame in 0..ctx.nframes() {
let input = inp.read(frame) as f64;
let g =
(std::f64::consts::PI
* (denorm::SFilter::freq(freq, frame) as f64)
* self.israte).tan();
let a1 = g / (1.0 + g);
let v1 = a1 * (input - self.z);
let v2 = v1 + self.z;
self.z = v2 + v1;
let (m0, m1) = (0.0, 1.0);
out.write(frame, (m0 * input + m1 * v2) as f32);
}
},
// from DAFX by will pirkle:
2 => {
for frame in 0..ctx.nframes() {
let input = inp.read(frame) as f64;
let o =
(-std::f64::consts::TAU
* (denorm::SFilter::freq(freq, frame) as f64)
* self.israte).cos();
let y = 2.0 - o;
let b = (y * y - 1.0).sqrt() - y;
let a = 1.0 + b;
self.z = a * input - b * self.z;
out.write(frame, self.z as f32);
}
},
// From https://en.wikipedia.org/wiki/RC_circuit
3 => {
for frame in 0..ctx.nframes() {
let input = inp.read(frame) as f64;
let c =
2.0
/ (std::f64::consts::TAU
* (denorm::SFilter::freq(freq, frame) as f64)
* self.israte);
let y = (input + self.z - self.y * (1.0 - c)) / (1.0 + c);
self.z = input;
self.y = y;
// highpass: self.z - self.y
out.write(frame, y as f32);
let freq = (denorm::SFilter::freq(freq, frame) as f64);
out.write(frame,
process_1pole_tpt_lowpass(input, freq, self.israte, &mut self.z)
as f32);
}
},
// // From https://en.wikipedia.org/wiki/RC_circuit
// // has the same output as the SVF variant, takes the same amount of time.
// 3 => {
// for frame in 0..ctx.nframes() {
// let input = inp.read(frame) as f64;
// let c =
// 2.0
// / (std::f64::consts::TAU
// * (denorm::SFilter::freq(freq, frame) as f64)
// * self.israte);
//
// let y = (input + self.z - self.y * (1.0 - c)) / (1.0 + c);
// self.z = input;
// self.y = y;
//
// // highpass: self.z - self.y
// out.write(frame, y as f32);
// }
// },
_ => {},
}
}