[panera] make and implement crate

README.md

@@ -64,6 +64,7 @@ the following is the current list of plugins
 - `double_reverse_delta_inverter`: idk, a weird distortion
 - `transmute_pitch`: pitch to midi converter
 - `reverter`: play sound backwards
+- `panera`: pan individual notes differently
 
 there's a bit of an explanation of each of the plugins below, but it's not a thorough documentation or a manual, it's just a bunch of notes i've written and a short description of the parameters
 
@@ -264,6 +265,28 @@ this plugin will introduce a delay of `length` samples, since it has to record t
 
 in my experience values between 5000 and 8000 tend to work well, but you might want to experiment a bit to see what works for you
 
+### panera
+
+ever wanted to have each pluck of the guitar have a different pan? do i have something for you then! 
+
+params:
+- `gain`: pregain added to the detector. doesn't affect output sound
+- `attack`: attack of the envelope follower
+- `release`: release of the envelope follower
+- `gate`: gate level at which a peak is detected
+
+- `panning mode`: one of {alternating [0, 0.33), sine [0.33, 0.66), random [0.66, 1]}
+- `lfo freq`: frequency for the sine lfo
+
+panera consists of a peak detector with a sample and hold lfo tied to the pan. this lfo is sampled each time a new peak comes in, and it's value will be held until the next peak
+
+there's three panning modes: 
+- alternating: each peak will be hard panned to a different side, alternating between left and right
+- sine: samples a sine lfo, and uses that as the pan for the rest of the note
+- random: each note will have a random pan
+
+the peak detector is still a bit fiddly, so you'll have to tweak the params a bit until it works for the kind of sound you're giving it. the defaults have worked great for me, so i recommend you start from there and change as you see fit
+
 ## contributing
 
 issues and prs are welcome, but please open an issue before making any big pr, i don't wanna have to reject a pr where you have put a lot of effort on. if you are fine with that, ig go ahead i'm not your mum

crates/panera/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "panera"
+version = "0.1.0"
+edition = "2018"
+
+[lib]
+crate-type = ["cdylib"]
+
+[dependencies]
+baseplug = { git = "https://github.com/wrl/baseplug.git", rev = "9cec68f31cca9c0c7a1448379f75d92bbbc782a8" }
+serde = "1.0.126"
+
+utils = { path = "../utils" }

crates/panera/src/lib.rs

@@ -0,0 +1,167 @@
+#![allow(incomplete_features)]
+#![feature(generic_associated_types)]
+
+use baseplug::{Plugin, ProcessContext};
+use serde::{Deserialize, Serialize};
+
+use utils::delay::*;
+use utils::envelope::*;
+
+const DELAY_LEN: usize = 200;
+
+baseplug::model! {
+    #[derive(Debug, Serialize, Deserialize)]
+    struct PaneraModel {
+        // peak detection options
+        #[model(min = 0.0, max = 3.0)]
+        #[parameter(name = "gain")]
+        gain: f32,
+        #[model(min = 0.0, max = 1.0)]
+        #[parameter(name = "attack")]
+        attack: f32,
+        #[model(min = 0.0, max = 1.0)]
+        #[parameter(name = "release")]
+        release: f32,
+        #[model(min = 0.0, max = 1.0)]
+        #[parameter(name = "gate")]
+        gate: f32,
+
+        // options to control the pan oscillation
+        #[model(min = 0.0, max = 1.0)]
+        #[parameter(name = "panning mode")]
+        panning_mode: f32,
+        #[model(min = 0.0, max = 10.0)]
+        #[parameter(name = "lfo freq")]
+        lfo_freq: f32,
+    }
+}
+
+impl Default for PaneraModel {
+    fn default() -> Self {
+        Self {
+            gain: 1.8,
+            attack: 0.0,
+            release: 0.27,
+            gate: 0.22,
+
+            panning_mode: 0.0,
+            lfo_freq: 1.0,
+        }
+    }
+}
+
+struct Panera {
+    /// envelope follower so we can detect peaks
+    envelope_follower: EnvelopeFollower,
+    /// whether we are currently on a peak
+    on: bool,
+    /// the current pan position
+    /// goes from 0 (left) to 1 (right)
+    pan: f32,
+    /// delay line is used so we don't change the pan after the peak has started
+    /// since to detect a peak we have to be halfway through it, if we change the pan
+    /// when we detect a peak, this means that it gets changed halfway, which results in a click
+    /// the delay makes it so we can detect a peak before actually playing it, therefore
+    /// allowing us to change the pan before the peak actually starts, and thus no clicks :)
+    delay: DelayLine<DELAY_LEN>,
+
+    lfo_idx: usize,
+}
+
+impl Plugin for Panera {
+    const NAME: &'static str = "panera";
+    const PRODUCT: &'static str = "panera";
+    const VENDOR: &'static str = "unnieversal";
+
+    const INPUT_CHANNELS: usize = 1;
+    const OUTPUT_CHANNELS: usize = 2;
+
+    type Model = PaneraModel;
+
+    #[inline]
+    fn new(_sample_rate: f32, _model: &PaneraModel) -> Self {
+        Self {
+            envelope_follower: EnvelopeFollower::new(),
+            on: true,
+            pan: 0.0,
+            delay: DelayLine::<DELAY_LEN>::new(),
+            lfo_idx: 0,
+        }
+    }
+
+    #[inline]
+    fn process(&mut self, model: &PaneraModelProcess, ctx: &mut ProcessContext<Self>) {
+        let input = &ctx.inputs[0].buffers;
+        let output = &mut ctx.outputs[0].buffers;
+
+        for i in 0..ctx.nframes {
+            // set values for env detector
+            self.envelope_follower.set_attack_release(
+                ctx.sample_rate,
+                model.attack[i],
+                model.release[i],
+            );
+
+            // process envelope detector with the non-delayed sample
+            let env = self.envelope_follower.process(input[0][i] * model.gain[i]);
+
+            // detect peak
+            if env > model.gate[i] && !self.on {
+                self.update_pan(
+                    model.panning_mode[i].into(),
+                    model.lfo_freq[i],
+                    ctx.sample_rate,
+                );
+
+                self.on = true;
+            }
+            if env < model.gate[i] && self.on {
+                self.on = false;
+            }
+
+            // increment lfo counter
+            self.lfo_idx += 1;
+
+            // update delay and get value
+            let s = self.delay.write_and_advance_get_last(input[0][i]);
+
+            // square pan law
+            // we play the delayed value
+            output[0][i] = self.pan.sqrt() * s;
+            output[1][i] = (1.0 - self.pan).sqrt() * s;
+        }
+    }
+}
+
+enum PanningMode {
+    Alternating,
+    Sine,
+    Random,
+}
+impl From<f32> for PanningMode {
+    fn from(a: f32) -> Self {
+        if a < 0.33 {
+            Self::Alternating
+        } else if a < 0.66 {
+            Self::Sine
+        } else {
+            Self::Random
+        }
+    }
+}
+
+impl Panera {
+    fn update_pan(&mut self, lfo_type: PanningMode, lfo_freq: f32, sample_rate: f32) {
+        self.pan = match lfo_type {
+            PanningMode::Alternating => 1.0 - self.pan,
+            PanningMode::Sine => ((self.lfo_idx as f32 * lfo_freq / sample_rate).sin() + 1.0) / 2.0,
+            PanningMode::Random => {
+                // idk tbh, just something kinda random ig
+                // i just want it to not be predictable
+                (((self.lfo_idx * (self.lfo_idx ^ 1234)) as f32 * lfo_freq).sin() + 1.0) / 2.0
+            }
+        }
+    }
+}
+
+baseplug::vst2!(Panera, b"pann");

crates/robotuna/src/lib.rs

@@ -170,17 +170,13 @@ impl RoboTuna {
         self.delay_idx_r += adv_r;
         self.true_idx += 1;
 
-        // get how close we are to the input idx, so we know if we have to interpolate/jump
-        let l_diff = self.true_idx as f32 - self.delay_idx_l;
-        let r_diff = self.true_idx as f32 - self.delay_idx_r;
-
         // get the current value
         let mut l = self.delays.l.floating_index(self.delay_idx_l);
         let mut r = self.delays.r.floating_index(self.delay_idx_r);
 
-        // Interpolation
+        // get how close we are to the input idx, so we know if we have to interpolate/jump
-        // if we are close to having to jump, we start interpolating with the jump destination
+        let l_diff = self.true_idx as f32 - self.delay_idx_l;
-        // interpolate when we're one third of the period away from jumping
+        let r_diff = self.true_idx as f32 - self.delay_idx_r;
 
         // TODO change to a non-linear interpolation
 
@@ -189,11 +185,22 @@ impl RoboTuna {
             let a = (l_diff - period_l) / (period_l / DIV);
             l *= a;
             l += (1.0 - a) * self.delays.l.floating_index(self.delay_idx_l - period_l);
+        // crossfade
+        // if we are close to having to jump, we start crossfading with the jump destination
+        // crossfade when we're one third of the period away from jumping
+        // when we get close to jumping back
+        if l_diff - period_l < cf_len_l {
+            // cross goes from 1 (when l_diff is at the max) to 0 (when l_diff == period_l)
+            let cross = (l_diff - period_l) / cf_len_l;
+            let (fade_in, fade_out) = ep_crossfade(1.0 - cross);
+            l = fade_out * l + fade_in * self.delays.l.floating_index(self.delay_idx_l - period_l);
         }
-        if 3.0 * period_l - l_diff < (period_l / DIV) {
+        // when we get close to jumping foward
-            let a = (3.0 * period_l - l_diff) / (period_l / DIV);
+        if MAX_PERIOD * period_l - l_diff < cf_len_l {
-            l *= a;
+            // cross goes from 1 (when l_diff is at the min) to 0 (when l_diff == 3.0 * period_l)
-            l += (1.0 - a) * self.delays.l.floating_index(self.delay_idx_l - period_l);
+            let cross = (MAX_PERIOD * period_l - l_diff) / cf_len_l;
+            let (fade_in, fade_out) = ep_crossfade(1.0 - cross);
+            l = fade_out * l + fade_in * self.delays.l.floating_index(self.delay_idx_l + period_l);
         }
         if r_diff - period_r < (period_r / DIV) {
             let a = (r_diff - period_r) / (period_r / DIV);

crates/utils/src/delay.rs

@@ -10,13 +10,7 @@ impl<const LEN: usize> DelayLine<LEN> {
         }
     }
 
-    pub fn read_slice(&self, slice: &mut [f32]) {
+    /// write to delay line and advance index
-        // Copy values in order
-        for i in 0..LEN {
-            slice[i] = self.wrapped_index(self.index + i);
-        }
-    }
-
     pub fn write_and_advance(&mut self, value: f32) {
         self.buffer[self.index] = value;
 
@@ -27,6 +21,13 @@ impl<const LEN: usize> DelayLine<LEN> {
         }
     }
 
+    /// write to delay line, advance index, and return the oldest sample
+    pub fn write_and_advance_get_last(&mut self, value: f32) -> f32 {
+        self.write_and_advance(value);
+
+        self.wrapped_index(self.index + 1)
+    }
+
     /// Returns the sample at idx after taking modulo LEN
     pub fn wrapped_index(&self, idx: usize) -> f32 {
         self.buffer[idx % LEN]
@@ -37,9 +38,8 @@ impl<const LEN: usize> DelayLine<LEN> {
         let idx = val.trunc() as usize;
         let frac = val.fract();
 
-        // TODO uhm idk what this should be, but we don't want an underflow so yeah,
         let xm1 = if idx == 0 {
-            0.0
+            self.wrapped_index(LEN - 1)
         } else {
             self.wrapped_index(idx - 1)
         };
@@ -62,6 +62,13 @@ impl<const LEN: usize> DelayLine<LEN> {
     pub fn buffer(&self) -> &[f32; LEN] {
         &self.buffer
     }
+
+    pub fn read_slice(&self, slice: &mut [f32]) {
+        // Copy values in order
+        for i in 0..LEN {
+            slice[i] = self.wrapped_index(self.index + i);
+        }
+    }
 }
 
 pub struct DelayLines<const LEN: usize> {

crates/utils/src/envelope.rs

@@ -0,0 +1,41 @@
+// from https://www.musicdsp.org/en/latest/Analysis/97-envelope-detector.html
+// with some modifications
+pub struct EnvelopeFollower {
+    x1: f32,
+    x2: f32,
+
+    ga: f32,
+    gr: f32,
+}
+
+impl EnvelopeFollower {
+    pub fn new() -> Self {
+        Self {
+            x1: 0.0,
+            x2: 0.0,
+            ga: 0.0,
+            gr: 0.0,
+        }
+    }
+
+    /// attack and release are in seconds
+    pub fn set_attack_release(&mut self, sample_rate: f32, attack: f32, release: f32) {
+        self.ga = (-1.0 / (sample_rate * attack)).exp();
+        self.gr = (-1.0 / (sample_rate * release)).exp();
+    }
+
+    pub fn process(&mut self, input: f32) -> f32 {
+        let in_abs = input.abs();
+
+        // 2nd order lowpass
+        if self.x1 < in_abs {
+            self.x1 = in_abs + self.ga * (self.x1 - in_abs);
+            self.x2 = self.x1 + self.ga * (self.x2 - self.x1);
+        } else {
+            self.x1 = in_abs + self.gr * (self.x1 - in_abs);
+            self.x2 = self.x1 + self.gr * (self.x2 - self.x1);
+        }
+
+        self.x2
+    }
+}

crates/utils/src/lib.rs

@@ -1,5 +1,6 @@
 pub mod buffers;
 pub mod delay;
+pub mod envelope;
 pub mod logs;
 pub mod pitch;
 pub mod threeband;