Changed slew logix to a real slew rate limiter

src/dsp/helpers.rs

@@ -705,8 +705,55 @@ impl TriggerSampleClock {
     }
 }
 
+/// A slew rate limiter, with a configurable time per 1.0 increase.
 #[derive(Debug, Clone, Copy)]
 pub struct SlewValue<F: Flt> {
+    current:        F,
+    slew_per_ms:    F,
+}
+
+impl<F: Flt> SlewValue<F> {
+    pub fn new() -> Self {
+        Self {
+            current:     f(0.0),
+            slew_per_ms: f(1000.0 / 44100.0),
+        }
+    }
+
+    pub fn reset(&mut self) {
+        self.current    = f(0.0);
+    }
+
+    pub fn set_sample_rate(&mut self, srate: F) {
+        self.slew_per_ms = f::<F>(1000.0) / srate;
+    }
+
+    #[inline]
+    pub fn value(&self) -> F { self.current }
+
+    /// * `slew_ms_per_1` - The time (in milliseconds) it should take
+    /// to get to 1.0 from 0.0.
+    #[inline]
+    pub fn next(&mut self, target: F, slew_ms_per_1: F) -> F {
+        // at 0.11ms, there are barely enough samples for proper slew.
+        if slew_ms_per_1 < f(0.11) {
+            self.current = target;
+
+        } else {
+            let max_delta = self.slew_per_ms / slew_ms_per_1;
+            self.current =
+                target
+                    .min(self.current + max_delta)
+                    .max(self.current - max_delta);
+        }
+
+        self.current
+    }
+}
+
+/// A ramped value changer, with a configurable time to reach the target value.
+#[derive(Debug, Clone, Copy)]
+pub struct RampValue<F: Flt> {
     slew_count: u64,
     current:    F,
     target:     F,
@@ -714,7 +761,7 @@ pub struct SlewValue<F: Flt> {
     sr_ms:      F,
 }
 
-impl<F: Flt> SlewValue<F> {
+impl<F: Flt> RampValue<F> {
     pub fn new() -> Self {
         Self {
             slew_count: 0,

src/dsp/mod.rs

@@ -610,7 +610,7 @@ define_exp!{n_env d_env 0.0, 1000.0}
 define_exp6!{n_lfot d_lfot 0.1,300000.0}
 define_exp!{n_time d_time 0.5,  5000.0}
 define_exp!{n_ftme d_ftme 0.1,  1000.0}
-define_exp!{n_ftmz d_ftmz 0.0,  1000.0}
+define_exp!{n_ftmz d_ftmz 0.0,  5000.0}
 
 // Special linear gain factor for the Out node, to be able
 // to reach more exact "1.0".
@@ -760,7 +760,7 @@ macro_rules! node_list {
                 (2 offs  n_id      d_id  r_id   f_def stp_d -1.0, 1.0, 0.0)
                 (3 min   n_id      d_id  r_id   f_def stp_d  0.0, 1.0, 0.0)
                 (4 max   n_id      d_id  r_id   f_def stp_d  0.0, 1.0, 1.0)
-                (5 slewt n_ftmz   d_ftmz r_fmz  f_ms  stp_m  0.0, 1.0, 10.0)
+                (5 slew  n_ftmz   d_ftmz r_fmz  f_ms  stp_m  0.0, 1.0, 75.0)
                 [0 sig],
             delay => Delay UIType::Generic UICategory::Signal
                (0  inp   n_id      d_id  r_id   f_def stp_d -1.0, 1.0, 0.0)

src/dsp/node_rndwk.rs

@@ -13,8 +13,9 @@ use crate::dsp::{
 #[derive(Debug, Clone)]
 pub struct RndWk {
     rng:        Rng,
-    slew_val:   SlewValue<f32>,
+    slew_val:   SlewValue<f64>,
     trig:       Trigger,
+    target:     f64,
 }
 
 impl RndWk {
@@ -28,6 +29,7 @@ impl RndWk {
             rng,
             trig:       Trigger::new(),
             slew_val:   SlewValue::new(),
+            target:     0.0,
         }
     }
 
@@ -52,16 +54,17 @@ impl RndWk {
         "RndWk max\nThe maximum of the new target value. If a value is drawn \
         that is outside of this range, it will be reflected back into it.\
         \nRange: (0..1)";
-    pub const slewt : &'static str =
+    pub const slew : &'static str =
-        "RndWk slewt\nThe slew time, the time it takes to reach the \
+        "RndWk slew\nThe slew rate limiting time. Thats the time it takes to \
-        new target value. This can be used to smooth off rough transitions and \
+        get to 1.0 from 0.0. Useful for smoothing modulation of audio signals. \
-        clicky noises.\nRange: (0..1)";
+        The higher the time, the smoother/slower the transition to new \
+        target values will be.\nRange: (0..1)";
     pub const sig : &'static str =
         "RndWk sig\nOscillator output\nRange: (-1..1)\n";
     pub const DESC : &'static str =
 r#"Random Walker
 
-This modulator generates a random number by walking a pre defined maximum random 'step' width. For smoother transitions a slew time is integrated.
+This modulator generates a random number by walking a pre defined maximum random 'step' width. For smoother transitions a slew rate limiter is integrated.
 "#;
     pub const HELP : &'static str =
 r#"RndWk - Random Walker
@@ -72,12 +75,12 @@ be folded within the defined 'min'/'max' range. The 'offs' parameter defines a
 minimal step width each 'trig' has to change the target value.
 
 For smoother transitions, if you want to modulate an audio signal with this,
-a slew time ('slewt') is integrated.
+a slew rate limiter ('slew') is integrated.
 
 You can disable all randomness by setting 'step' to 0.0.
 
-Tip: Interesting and smooth results can be achieved if you set 'slewt'
+Tip: Interesting and smooth results can be achieved if you set 'slew'
-to a longer time than the interval in that you trigger 'trig'. It will smooth
+to a (way) longer time than the 'trig' interval. It will smooth
 off the step widths and the overall motion even more.
 "#;
 
@@ -87,12 +90,13 @@ impl DspNode for RndWk {
     fn outputs() -> usize { 1 }
 
     fn set_sample_rate(&mut self, srate: f32) {
-        self.slew_val.set_sample_rate(srate);
+        self.slew_val.set_sample_rate(srate as f64);
     }
 
     fn reset(&mut self) {
         self.slew_val.reset();
         self.trig.reset();
+        self.target = 0.0;
     }
 
     #[inline]
@@ -109,7 +113,7 @@ impl DspNode for RndWk {
         let offs    = inp::RndWk::offs(inputs);
         let min     = inp::RndWk::min(inputs);
         let max     = inp::RndWk::max(inputs);
-        let slewt   = inp::RndWk::slewt(inputs);
+        let slew    = inp::RndWk::slew(inputs);
         let out     = out::RndWk::sig(outputs);
 
         for frame in 0..ctx.nframes() {
@@ -125,17 +129,19 @@ impl DspNode for RndWk {
                 let offs = denorm::RndWk::offs(offs, frame).clamp(-1.0, 1.0);
 
                 let target =
-                    self.slew_val.value()
+                    self.slew_val.value() as f32
                     + ((self.rng.next() * 2.0 * step) - step)
                     + offs;
-                let target = ((target - min) % delta).abs() + min;
+                self.target = (((target - min) % delta).abs() + min) as f64;
-
-                let slew_time_ms = denorm::RndWk::slewt(slewt, frame);
-
-                self.slew_val.set_target(target, slew_time_ms);
             }
 
-            out.write(frame, self.slew_val.next());
+            let slew_time_ms = denorm::RndWk::slew(slew, frame);
+
+            out.write(
+                frame,
+                self.slew_val.next(
+                    self.target,
+                    slew_time_ms as f64) as f32);
         }
 
         ctx_vals[0].set(out.read(ctx.nframes() - 1));