From 52d457e587ee22b17bbaf792528c4091259131f0 Mon Sep 17 00:00:00 2001
From: Nathan Graule <solarliner@gmail.com>
Date: Tue, 6 Feb 2024 23:17:58 +0100
Subject: [PATCH] refactor: move OpAmp saturator into dsp

---
 examples/svfmixer/src/dsp.rs | 41 ++++++++++++++++++++++++++++++++----
 examples/svfmixer/src/lib.rs | 38 +++++----------------------------
 2 files changed, 42 insertions(+), 37 deletions(-)

diff --git a/examples/svfmixer/src/dsp.rs b/examples/svfmixer/src/dsp.rs
index d453772..44a7075 100644
--- a/examples/svfmixer/src/dsp.rs
+++ b/examples/svfmixer/src/dsp.rs
@@ -1,12 +1,14 @@
-use crate::OpAmp;
 use enum_map::{enum_map, Enum, EnumMap};
 use nalgebra::SMatrix;
+use nih_plug::util::db_to_gain_fast;
 use valib::dsp::blocks::ModMatrix;
 use valib::dsp::parameter::{HasParameters, Parameter, SmoothedParam};
 use valib::dsp::DSP;
 use valib::filters::svf::Svf;
 use valib::oversample::Oversampled;
+use valib::saturators::{Clipper, Saturator, Slew};
 use valib::simd::{AutoSimd, SimdValue};
+use valib::Scalar;
 
 type Sample = AutoSimd<[f32; 2]>;
 
@@ -81,16 +83,47 @@ impl HasParameters for DspInner {
 impl DSP<1, 1> for DspInner {
     type Sample = Sample;
 
-    fn process(&mut self, x: [Self::Sample; 1]) -> [Self::Sample; 1] {
+    fn process(&mut self, [x]: [Self::Sample; 1]) -> [Self::Sample; 1] {
         self.filter
             .set_cutoff(Sample::splat(self.params[DspParam::Cutoff].next_sample()));
         self.filter.set_r(Sample::splat(
-            self.params[DspParam::Resonance].next_sample(),
+            1.0 - self.params[DspParam::Resonance].next_sample(),
         ));
         self.mod_matrix.weights.x = Sample::splat(self.params[DspParam::LpGain].next_sample());
         self.mod_matrix.weights.y = Sample::splat(self.params[DspParam::BpGain].next_sample());
         self.mod_matrix.weights.z = Sample::splat(self.params[DspParam::HpGain].next_sample());
 
-        self.mod_matrix.process(self.filter.process(x))
+        let drive = Sample::splat(db_to_gain_fast(self.params[DspParam::Drive].next_sample()));
+        let [out] = self.mod_matrix.process(self.filter.process([x * drive]));
+        [out / drive]
+    }
+}
+
+#[derive(Debug, Clone, Copy)]
+struct OpAmp<T>(Clipper, Slew<T>);
+
+impl<T: Scalar> Default for OpAmp<T> {
+    fn default() -> Self {
+        Self(Default::default(), Default::default())
+    }
+}
+
+impl<T: Scalar> Saturator<T> for OpAmp<T>
+where
+    Clipper: Saturator<T>,
+    Slew<T>: Saturator<T>,
+{
+    fn saturate(&self, x: T) -> T {
+        self.1.saturate(self.0.saturate(x))
+    }
+
+    fn sat_diff(&self, x: T) -> T {
+        self.0.sat_diff(x) * self.1.sat_diff(self.0.saturate(x))
+    }
+
+    fn update_state(&mut self, x: T, y: T) {
+        let xc = self.0.saturate(x);
+        self.0.update_state(x, xc);
+        self.1.update_state(xc, y);
     }
 }
diff --git a/examples/svfmixer/src/lib.rs b/examples/svfmixer/src/lib.rs
index 9dacf4e..5a45bd7 100644
--- a/examples/svfmixer/src/lib.rs
+++ b/examples/svfmixer/src/lib.rs
@@ -7,7 +7,7 @@ use valib::dsp::parameter::HasParameters;
 use valib::dsp::utils::{slice_to_mono_block, slice_to_mono_block_mut};
 use valib::dsp::DSPBlock;
 use valib::oversample::Oversample;
-use valib::saturators::{Clipper, Saturator, Slew};
+use valib::saturators::Saturator;
 use valib::simd::SimdValue;
 use valib::{dsp::DSP, Scalar};
 
@@ -67,6 +67,7 @@ impl PluginParams {
             )
             .with_value_to_string(formatters::v2s_f32_gain_to_db(2))
             .with_string_to_value(formatters::s2v_f32_gain_to_db())
+            .with_unit(" dB")
             .bind_to_parameter(dsp.get_parameter(DspParam::Drive)),
             fc: FloatParam::new(
                 "Frequency",
@@ -94,7 +95,7 @@ impl PluginParams {
             )
             .with_value_to_string(formatters::v2s_f32_gain_to_db(2))
             .with_string_to_value(formatters::s2v_f32_gain_to_db())
-            .with_unit("dB")
+            .with_unit(" dB")
             .bind_to_parameter(dsp.get_parameter(DspParam::LpGain)),
             bp_gain: FloatParam::new(
                 "BP Gain",
@@ -108,7 +109,7 @@ impl PluginParams {
             )
             .with_value_to_string(formatters::v2s_f32_gain_to_db(2))
             .with_string_to_value(formatters::s2v_f32_gain_to_db())
-            .with_unit("dB")
+            .with_unit(" dB")
             .bind_to_parameter(dsp.get_parameter(DspParam::BpGain)),
             hp_gain: FloatParam::new(
                 "HP Gain",
@@ -122,41 +123,12 @@ impl PluginParams {
             )
             .with_value_to_string(formatters::v2s_f32_gain_to_db(2))
             .with_string_to_value(formatters::s2v_f32_gain_to_db())
-            .with_unit("dB")
+            .with_unit(" dB")
             .bind_to_parameter(dsp.get_parameter(DspParam::HpGain)),
         }
     }
 }
 
-#[derive(Debug, Clone, Copy)]
-struct OpAmp<T>(Clipper, Slew<T>);
-
-impl<T: Scalar> Default for OpAmp<T> {
-    fn default() -> Self {
-        Self(Default::default(), Default::default())
-    }
-}
-
-impl<T: Scalar> Saturator<T> for OpAmp<T>
-where
-    Clipper: Saturator<T>,
-    Slew<T>: Saturator<T>,
-{
-    fn saturate(&self, x: T) -> T {
-        self.1.saturate(self.0.saturate(x))
-    }
-
-    fn sat_diff(&self, x: T) -> T {
-        self.0.sat_diff(x) * self.1.sat_diff(self.0.saturate(x))
-    }
-
-    fn update_state(&mut self, x: T, y: T) {
-        let xc = self.0.saturate(x);
-        self.0.update_state(x, xc);
-        self.1.update_state(xc, y);
-    }
-}
-
 struct SvfMixerPlugin {
     params: Arc<PluginParams>,
     dsp: Dsp,