feat: adding lfo to filter

core/Filter.cpp

@@ -1,6 +1,5 @@
 #include "Filter.hpp"
 #include <cmath>
-#include <sys/types.h>
 
 #ifndef M_PI
 #define M_PI 3.14159265358979323846
@@ -15,15 +14,24 @@ Filter::Filter(float initCutOff, float initQ, float initSampleRate)
 
 Filter::FilterType Filter::getType() const { return type_; }
 
+float Filter::clampFreq(float freq) {
+  return std::fmin(std::fmax(freq, kFilterMin), kFilterMax);
+}
+
 void Filter::updateCoeffs() {
-  float f = (cutOff_ + modulation_) / std::fmax(sampleRate_, 1.0f);
+  float totalFreq = clampFreq(cutOff_ + modulation_);
+
+  float f = totalFreq / std::fmax(sampleRate_, 1.0f);
+
   if (f > kMaxNormalizedFrequency)
     f = kMaxNormalizedFrequency;
+  if (f < 0.0001f)
+    f = 0.0001f;
+
   g_ = 2.0f * std::sin(M_PI * f);
 }
 
 float Filter::processFrame(float input, float &lp, float &bp) const {
-
   float hp = input - (bp / q_) - lp;
 
   bp = bp + g_ * hp;
@@ -48,8 +56,11 @@ void Filter::process(const float *in, float *out, uint32_t frames,
   float bp = bpL_;
 
   for (uint32_t i = 0; i < frames; ++i) {
-    if (modulation != nullptr)
+    if (modulation != nullptr) {
+      if (std::abs(modulation[i] - modulation_) > 0.001f) {
         setModulation(modulation[i]);
+      }
+    }
     out[i] = processFrame(in[i], lp, bp);
   }
 
@@ -64,10 +75,17 @@ void Filter::processStereo(const float *inL, const float *inR, float *outL,
   float lpR = lpR_, bpR = bpR_;
 
   for (uint32_t i = 0; i < frames; ++i) {
-    if (modulation != nullptr)
+    if (modulation != nullptr) {
+      if (std::abs(modulation[i] - modulation_) > 0.001f) {
         setModulation(modulation[i]);
-    outL[i] = processFrame(inL[i], lpL, bpL);
+      }
-    outR[i] = processFrame(inR[i], lpR, bpR);
+    }
+
+    float inValL = (inL != nullptr) ? inL[i] : 0.0f;
+    float inValR = (inR != nullptr) ? inR[i] : 0.0f;
+
+    outL[i] = processFrame(inValL, lpL, bpL);
+    outR[i] = processFrame(inValR, lpR, bpR);
   }
 
   lpL_ = lpL;
@@ -77,29 +95,35 @@ void Filter::processStereo(const float *inL, const float *inR, float *outL,
 }
 
 float Filter::getCutOff() const { return cutOff_; }
+
 void Filter::setCutOff(float freq) {
-  cutOff_ = std::fmax(freq, 1.0f);
+  cutOff_ = clampFreq(freq);
   updateCoeffs();
 }
 
 float Filter::getQ() const { return q_; }
+
 void Filter::setQ(float q) {
-  q_ = std::fmax(q, 0.1f);
+  q_ = std::fmin(std::fmax(q, kQMin), kQMax);
   updateCoeffs();
 }
 
 void Filter::setType(FilterType type) { type_ = type; }
 
 float Filter::getSampleRate() const { return sampleRate_; }
+
 void Filter::setSampleRate(float sr) {
+  if (sr > 0.0f) {
     sampleRate_ = sr;
     updateCoeffs();
   }
+}
 
 float Filter::getModulation() const { return modulation_; }
+
 void Filter::setModulation(float mod) {
-  if (modulation_ == mod)
+  if (std::abs(modulation_ - mod) > 0.0001f) {
-    return;
     modulation_ = mod;
     updateCoeffs();
   }
+}

core/Filter.hpp

@@ -4,6 +4,10 @@
 #include <cstdint>
 
 constexpr float kMaxNormalizedFrequency = 0.16667f;
+constexpr float kFilterMin = 20.0f;
+constexpr float kFilterMax = 10000.0f;
+constexpr float kQMin = 0.1f;
+constexpr float kQMax = 20.0f;
 
 class Filter {
 public:
@@ -34,6 +38,7 @@ private:
   void updateCoeffs();
   float modulation_;
 
+  float clampFreq(float freq);
   float processFrame(float input, float &lp, float &bp) const;
 
   float cutOff_;

core/Oscillator.cpp

@@ -22,6 +22,8 @@ void Oscillator::process(float *out, uint32_t frames) {
   }
 }
 
+void Oscillator::reset() { phase_ = 0; }
+
 void Oscillator::recalc_() { inc_ = freq_ / sampleRate_; }
 
 void Oscillator::setFrequency(float newFreq) {

core/Oscillator.hpp

@@ -26,6 +26,8 @@ public:
   void setWaveShape(WaveShape shape);
   WaveShape getWaveShape() const;
 
+  void reset();
+
 private:
   float freq_;
   float gain_;

plugins/SquidgeFilter/DistrhoPluginInfo.h

@@ -11,6 +11,8 @@
 
 #define DISTRHO_PLUGIN_NUM_PARAMETERS 3
 
+#define DISTRHO_PLUGIN_WANT_TIMEPOS 1
+
 #define DISTRHO_PLUGIN_WANT_PROGRAMS 0
 #define DISTRHO_PLUGIN_WANT_STATE 0
 

plugins/SquidgeFilter/SquidgeFilter.cpp

@@ -16,12 +16,14 @@ public:
     kParamFreq,
     kParamResonance,
     kParamType,
+    kParamLFOSyncMode,
+    kParamLFOAmount,
     kParameterCount // must be last
   };
 
-  SquidgeFilter() // Note: Constructor name must match class name
+  SquidgeFilter()
       : Plugin(kParameterCount, 0, 0), filter_(1000.0f, 0.707f, 48000.0f),
-        lfo_(4.0f) { // Default: 1kHz, Q=0.707
+        lfo_(4.0f) {
     filter_.setType(Filter::kLowPass);
   }
 
@@ -73,6 +75,34 @@ protected:
       parameter.enumValues.values =
           const_cast<ParameterEnumerationValue *>(sTypes);
       break;
+    case kParamLFOAmount:
+      parameter.name = "LFO Amount";
+      parameter.symbol = "lfoamount";
+      parameter.ranges.min = 0.0f;
+      parameter.ranges.def = 0.0f;
+      parameter.ranges.max = 1000.0f;
+
+      parameter.hints = kParameterIsAutomatable | kParameterIsInteger;
+      break;
+    case kParamLFOSyncMode:
+      parameter.name = "LFO Sync";
+      parameter.symbol = "lfosync";
+      parameter.ranges.min = 0.0f;
+      parameter.ranges.def = 3.0f;
+      parameter.ranges.max = 6.0f;
+
+      parameter.hints = kParameterIsAutomatable | kParameterIsInteger;
+
+      static const ParameterEnumerationValue sModes[] = {
+          {0.0f, "1/1 Bar"}, {1.0f, "1/2 Bar"},  {2.0f, "1/4 Bar"},
+          {3.0f, "1/8 Bar"}, {4.0f, "1/16 Bar"}, {5.0f, "1/32 Bar"},
+          {6.0f, "1/64 Bar"}};
+
+      parameter.enumValues.count = 7;
+      parameter.enumValues.restrictedMode = true;
+      parameter.enumValues.values =
+          const_cast<ParameterEnumerationValue *>(sModes);
+      break;
     }
   }
 
@@ -84,7 +114,12 @@ protected:
       return filter_.getQ();
     case kParamType:
       return static_cast<float>(filter_.getType());
-    }
+    case kParamLFOAmount:
+      return lfo_.getGain();
+      break;
+    case kParamLFOSyncMode:
+      return lfoSync_;
+    };
     return 0.0f;
   }
 
@@ -96,6 +131,12 @@ protected:
     case kParamResonance:
       filter_.setQ(value);
       break;
+    case kParamLFOAmount:
+      lfo_.setGain(value);
+      break;
+    case kParamLFOSyncMode:
+      lfoSync_ = value;
+      break;
     case kParamType:
       int typeIdx = static_cast<int>(std::fmin(std::fmax(value, 0.0f), 3.0f));
       filter_.setType(static_cast<Filter::FilterType>(typeIdx));
@@ -104,6 +145,39 @@ protected:
   }
 
   void run(const float **inputs, float **outputs, uint32_t frames) override {
+
+    const TimePosition &timePos = getTimePosition();
+
+    float targetFreq = 4.0f;
+    int syncIndex = static_cast<int>(lfoSync_);
+
+    if (syncIndex < 0)
+      syncIndex = 0;
+    if (syncIndex > 6)
+      syncIndex = 6;
+
+    if (timePos.bbt.valid && timePos.playing &&
+        timePos.bbt.beatsPerMinute > 0.0) {
+      float bpm = static_cast<float>(timePos.bbt.beatsPerMinute);
+
+      float baseFreq = (bpm / 60.0f) * 4.0f;
+
+      static const float multipliers[] = {1.0f,  2.0f,  4.0f, 8.0f,
+                                          16.0f, 32.0f, 64.0f};
+
+      targetFreq = baseFreq * multipliers[syncIndex];
+
+      static int lastBar = -1;
+      if (timePos.bbt.bar != lastBar) {
+        lfo_.reset();
+        lastBar = timePos.bbt.bar;
+      }
+    } else {
+
+      targetFreq = 1.0f;
+    }
+
+    lfo_.setFrequency(targetFreq);
     lfo_.process(lfoBuffer_, frames);
 
     filter_.processStereo(inputs[0], inputs[1], outputs[0], outputs[1], frames,
@@ -118,6 +192,7 @@ protected:
 private:
   Filter filter_;
   Oscillator lfo_;
+  float lfoSync_;
   float lfoBuffer_[BUFFER_SIZE];
 
   DISTRHO_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR(SquidgeFilter);