Reorganized file structure to allow building Arduino project

AudioThread.cpp

@@ -1,7 +1,9 @@
+#include <mutex>
 #include "AudioThread.h"
 #include "SharedState.h"
 #include <I2S.h>
 #include <math.h>
+#include "synth_engine.h"
 
 // I2S Pin definitions
 // You may need to change these to match your hardware setup (e.g., for a specific DAC).
@@ -16,6 +18,8 @@ const int16_t AMPLITUDE = 16383; // Use a lower amplitude to avoid clipping (max
 // Create an I2S output object
 I2S i2s(OUTPUT);
 
+extern SynthEngine* globalSynth;
+
 // --- Synthesizer State ---
 float currentFrequency = 440.0f;
 double phase = 0.0;
@@ -36,6 +40,9 @@ void setupAudio() {
 
   // Seed the random number generator from an unconnected analog pin
   randomSeed(analogRead(A0));
+  
+  // Initialize the portable synth engine
+  globalSynth = new SynthEngine(SAMPLE_RATE);
 }
 
 void loopAudio() {
@@ -52,34 +59,20 @@ void loopAudio() {
     int semitoneOffset = SCALES[currentScaleIndex].semitones[noteIndex];
     currentFrequency = keyFrequency * pow(2.0f, semitoneOffset / 12.0f);
 
+    if (globalSynth) {
+        globalSynth->setFrequency(currentFrequency);
+        globalSynth->setGate(true); // Trigger envelope
+    }
     Serial.println("Playing note: " + String(currentFrequency) + " Hz");
   }
 
-  // Generate the sine wave sample
-  int16_t sample;
-  double phaseIncrement = 2.0 * M_PI * currentFrequency / SAMPLE_RATE;
-  phase = fmod(phase + phaseIncrement, 2.0 * M_PI);
+  // Process a small batch of samples
+  int16_t samples[32];
+  if (globalSynth) globalSynth->process(samples, 32);
+  else memset(samples, 0, sizeof(samples));
 
-  switch (currentWavetableIndex) {
-    case 0: // Sine
-        sample = static_cast<int16_t>(AMPLITUDE * sin(phase));
-        break;
-    case 1: // Square
-        sample = (phase < M_PI) ? AMPLITUDE : -AMPLITUDE;
-        break;
-    case 2: // Saw
-        sample = static_cast<int16_t>(AMPLITUDE * (1.0 - (phase / M_PI)));
-        break;
-    case 3: // Triangle
-        sample = static_cast<int16_t>(AMPLITUDE * (2.0 * fabs(phase / M_PI - 1.0) - 1.0));
-        break;
-    default:
-        sample = 0;
-        break;
+  for (int i = 0; i < 32; ++i) {
+      i2s.write(samples[i]);
+      i2s.write(samples[i]);
   }
-
-  // Write the same sample to both left and right channels (mono audio).
-  // This call is blocking and will wait until there is space in the DMA buffer.
-  i2s.write(sample);
-  i2s.write(sample);
 }