SVF library element

xybrid/nodelib/svfilter.cpp

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+#include "svfilter.h"
+
+#include <cmath>
+
+#include "nodelib/basics.h"
+#include "audio/audioengine.h"
+
+using Xybrid::NodeLib::SVFilter;
+using Xybrid::Data::AudioFrame;
+using namespace Xybrid::Audio;
+
+void SVFilter::process(AudioFrame in, double freq, double res, int ovs) {
+    if (poles <= 0) return;
+
+    double f = freq / (audioEngine->curSampleRate() * ovs);
+    double q = sqrt(1.0 - atan(sqrt(res)) * 2.0 / PI);
+    double damp = sqrt(q);
+
+    for (int i = 0; i < ovs; i++) {
+        low += band*f;
+        high = in*damp - low - band*q;
+        band += high*f;
+    }
+    notch = high+low;
+}

xybrid/nodelib/svfilter.h

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+#pragma once
+
+#include <cstring>
+
+#include "data/audioframe.h"
+
+namespace Xybrid::NodeLib {
+    class SVFilter {
+        //
+    public:
+        Data::AudioFrame low = 0.0;
+        Data::AudioFrame high = 0.0;
+        Data::AudioFrame band = 0.0;
+        Data::AudioFrame notch = 0.0;
+
+        SVFilter() = default;
+        ~SVFilter() = default;
+        inline SVFilter(const SVFilter& o) { std::memcpy(this, &o, sizeof(SVFilter)); } // trivial enough contents
+        inline SVFilter& operator=(const SVFilter& o) { std::memcpy(this, &o, sizeof(SVFilter)); return *this; } // same
+
+        void process(Data::AudioFrame in, double freq, double res, int oversamp = 2);
+        inline void reset() { low = 0.0; high = 0.0; band = 0.0; notch = 0.0; }
+    };
+}