feat(filter): Add modulation support and LFO integration

core/Oscillator.cpp

@@ -0,0 +1,44 @@
+#include "Oscillator.hpp"
+
+#include <cmath>
+
+Oscillator::Oscillator(float initFreq)
+    : freq_(initFreq), gain_(100.0f), waveShape_(kWaveShapeSine),
+      sampleRate_(48000.f), phase_(0.0f), inc_(0.0f) {
+  recalc_();
+};
+
+void Oscillator::process(float *out, uint32_t frames) {
+  for (uint32_t i = 0; i < frames; ++i) {
+    switch (waveShape_) {
+    default:
+    case kWaveShapeSine:
+      out[i] = std::sinf(phase_ * 2.0f * M_PI) * gain_;
+      break;
+    }
+    phase_ += inc_;
+    if (phase_ >= 1.0f)
+      phase_ -= 1.0f;
+  }
+}
+
+void Oscillator::recalc_() { inc_ = freq_ / sampleRate_; }
+
+void Oscillator::setFrequency(float newFreq) {
+  freq_ = std::fmax(newFreq, 0.0f);
+}
+float Oscillator::getFrequency() const { return freq_; };
+
+void Oscillator::setGain(float newGain) {
+  gain_ = newGain > 0 ? newGain : 1.0f;
+}
+float Oscillator::getGain() const { return gain_; };
+
+void Oscillator::setSampleRate(float newSampleRate) {
+  sampleRate_ = newSampleRate > 0 ? newSampleRate : 48000.0f;
+  recalc_();
+}
+float Oscillator::getSampleRate() const { return sampleRate_; }
+
+void Oscillator::setWaveShape(WaveShape shape) { waveShape_ = shape; }
+Oscillator::WaveShape Oscillator::getWaveShape() const { return waveShape_; }