add oscillator class

src/synth/Oscillator.h

@@ -1,4 +1,50 @@
 
-# pragma once
+#pragma once
 
-// placeholder
+#include <cstdint>
+#include <cmath>
+#include <array>
+
+#ifndef M_PI // I hate my stupid chungus life
+    #define M_PI 3.14159265358979323846
+#endif
+
+// TODO: you get it, also in a yml config
+#define SYNTH_PITCH_STANDARD 440.0f // frequency of home pitch
+#define SYNTH_MIDI_HOME 69 // midi note index of home pitch
+#define SYNTH_NOTES_PER_OCTAVE 12
+#define SYNTH_WAVETABLE_SIZE 2048
+
+class Oscillator {
+public:
+
+    Oscillator() = default;
+    ~Oscillator() = default;
+
+    void setWavetable(uint8_t waveTableId);
+    void setSampleRate(float sampleRate);
+    float frequency();
+
+    float process(uint8_t note, bool& scopeTrigger);
+    float process(float frequency, bool& scopeTrigger);
+
+private:
+
+    float sampleRate_ = 44100.0f;
+
+    inline float noteToFrequency(uint8_t note);
+
+    // internal state tracking
+    float phase_ = 0.0f;
+    uint8_t activeWavetable_;
+    float frequency_ = 220.0f;
+
+    // TODO: implement
+    // TODO: wavetable class that can load from files
+    // TODO: wavetables should be shared among the entire synth
+    std::array<float, SYNTH_WAVETABLE_SIZE> wavetable1_;
+    std::array<float, SYNTH_WAVETABLE_SIZE> wavetable2_;
+    std::array<float, SYNTH_WAVETABLE_SIZE> wavetable3_;
+    std::array<float, SYNTH_WAVETABLE_SIZE> wavetable4_;
+
+};