more correct SVF

notes

@@ -32,14 +32,24 @@ parameters {
 
 TODO {
     immediate frontburner {
-        - fix focus issues after loading a project with patchboard focused
-        - wet-only output for delay (be smart about it)
-        
         revert action
         
         distortion effect
     }
     
+    shift+drag fine tuning for KnobGadget
+    
+    automation node {
+        listens for one specific param
+        supports tweening
+        value bounds, scaling exponent
+        
+        how to UI?
+        I guess some sort of text box/spinner to enter bounds
+        dial for exponent
+        focusable control to set param
+    }
+    
     qt update causing some patchboard artifacting on mouse movement
     
     look into performance/timing/sync of audio engine; it's having buffer issues way more than it feels like it should

xybrid/nodelib/svfilter.cpp

@@ -9,11 +9,10 @@ using namespace Xybrid::Audio;
 
 void SVFilter::process(AudioFrame in, double freq, double res, int ovs) {
     if (ovs <= 0) return;
+    res = std::max(res, 0.01);
 
-    //double f = freq / (audioEngine->curSampleRate() * ovs);
-    double f = 2.0 * std::sin(freq / (audioEngine->curSampleRate() * ovs));
-    //double f = 2.0 * std::sin(PI * std::min(0.25, freq / (audioEngine->curSampleRate() * ovs)));
-    double q = std::sqrt(1.0 - std::atan(sqrt(res)) * 2.0 / PI);
+    double f = 2.0 * std::sin(PI * freq / (audioEngine->curSampleRate() * ovs));
+    double q = std::sqrt(1.0 - std::atan(std::sqrt(res)) * 2.0 / PI);
     double damp = std::sqrt(q);
 
     for (int i = 0; i < ovs; i++) {

xybrid/nodelib/svfilter.h

@@ -8,6 +8,9 @@ namespace Xybrid::NodeLib {
     class SVFilter {
         //
     public:
+        /// Default oversampling level. Enough to mostly eliminate artifacting at high cutoff.
+        static const constexpr int DEFAULT_OVERSAMP = 3;
+
         Data::AudioFrame low = 0.0;
         Data::AudioFrame high = 0.0;
         Data::AudioFrame band = 0.0;
@@ -19,7 +22,7 @@ namespace Xybrid::NodeLib {
         inline SVFilter(const SVFilter& o) { std::memcpy(static_cast<void*>(this), static_cast<const void*>(&o), sizeof(SVFilter)); }
         inline SVFilter& operator=(const SVFilter& o) { std::memcpy(static_cast<void*>(this), static_cast<const void*>(&o), sizeof(SVFilter)); return *this; }
 
-        void process(Data::AudioFrame in, double freq, double res, int oversamp = 2);
+        void process(Data::AudioFrame in, double freq, double res, int oversamp = DEFAULT_OVERSAMP);
         inline void reset() { low = 0.0; high = 0.0; band = 0.0; notch = 0.0; }
     };
 }

xybrid/nodes/effect/svf.cpp

@@ -132,7 +132,7 @@ void SVF::onGadgetCreated() {
         return qs("?");
     };
 
-    (new KnobGadget(l))->bind(frequency)->setLabel(qs("Freq"))->setRange(0.0, 25000.0, 10.0, KnobGadget::NoStep)->setDefault(6440.0);
+    (new KnobGadget(l))->bind(frequency)->setLabel(qs("Freq"))->setRange(0.0, 16000.0, 50.0, KnobGadget::NoStep)->setDefault(6400.0);
     (new KnobGadget(l))->bind(resonance)->setLabel(qs("Res"))->setRange(0.0, 100.0, 1.0)->setDefault(0.0);
     (new KnobGadget(l))->bind(mode)->setLabel(qs("Mode"))->setTextFunc(modetxt)->setRange(0, Notch, 1, KnobGadget::BigStep)->setDefault(0);
 }