oscillator.c

typedef struct {
  float current_step;
  float step_size;
  float volume;
} oscillator;

oscillator oscillate(float rate, float volume) {
  oscillator o = {
      .current_step = 0,
      .volume = volume,
      .step_size = (2 * M_PI) / rate,
  };
  return o;
}

float next(oscillator *os) {
  os->current_step += os->step_size;
  return sinf(os->current_step) * os->volume;
}

// using the oscillator:
float A4_freq = (float)SAMPLE_RATE / 440.00f;
a4 = oscillate(A4_freq, 0.8f)

next(a4); // returns the next sample point in the A4 sine wave