nativeSquare

square wave oscillator with "active" control Bandwith limited with sync input. Sync resets oscillator phase on rising zero-crossing
Author: Johannes Taelman (editted by Remco van der Most)
License: BSD
Github: sss/osc/nativeSquare.axo

Inlets

frac32buffer sync, resets phase on rising zero-crossing

bool32 active

frac32.bipolar pitch

Outlets

frac32buffer.bipolar square wave, anti-aliased

Parameters

frac32.s.map.pitch pitch

Declaration
int32_t osc_p;
static const int blepvoices = 8;
int16_t *oscp[blepvoices];
uint32_t nextvoice;
int32_t i0;
Init
int j;
for (j = 0; j < blepvoices; j++)
  oscp[j] = &blept[BLEPSIZE - 1];
nextvoice = 0;
i0 = 0;
Control Rate
if (inlet_active > 0) {
  int32_t freq;
  MTOFEXTENDED(param_pitch + inlet_pitch, freq);
  int j;
  int16_t *lastblep = &blept[BLEPSIZE - 1];
  for (j = 0; j < BUFSIZE; j++) {
    int i;
    int p;
    p = osc_p;
    osc_p = p + (freq << 1);
    int32_t sum = 0;
    int i1 = inlet_sync[j] >> 2;
    if ((i1 > 0) && !(i0 > 0)) { // phase reset
      int32_t x = 64 - ((-i0 << 6) / (i1 - i0));
      osc_p = x * (freq >> 6);
      if (nextvoice & 1) {
        nextvoice = (nextvoice + 1) & (blepvoices - 1);
        oscp[nextvoice] = &blept[x];
      }
    } else if ((osc_p > 0) && !(p > 0)) { // dispatch
      nextvoice = (nextvoice + 1) & (blepvoices - 1);
      int32_t x = osc_p / (freq >> 5);
      oscp[nextvoice] = &blept[x];
    }
    i0 = i1;
    for (i = 0; i < blepvoices; i++) { // sample
      int16_t *t = oscp[i];
      if (i & 1)
        sum += *t;
      else
        sum -= *t;
      t += 64;
      if (t >= lastblep)
        t = lastblep;
      oscp[i] = t;
    }
    sum -= ((((nextvoice + 1) & 1) << 1) - 1) << 13;
    outlet_wave[j] = sum << 13;
  }
}
Audio Rate
if (inlet_active == 0) {
  outlet_wave = 0;
}

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