DragonRuby Libpd

ext.c

static void audio_callback(void *userdata, Uint8 *stream, int len) {
  float *inbuf = (float *)stream; // Point inbuf to the stream
  int num_samples = len / sizeof(float); // Total number of float samples
  int ticks = num_samples / 64 * 2; // Each tick is 64 samples per channel (128 samples total)

  float outbuf[num_samples]; // Allocate outbuf on the stack with the same size as inbuf

  // Process the samples
  libpd_process_float(ticks, inbuf, outbuf);

  // Copy output samples back to the stream
  memcpy(stream, outbuf, len);
}

static void start_processing()
{
  drb_api->drb_log_write("Game", 2, "* INFO - Starting processing");

  SDL_AudioSpec want, have;
  drb_api->SDL_memset(&want, 0, sizeof(want));
  // TODO populate from ivars
  want.freq = 48000; // Sample rate
  want.format = AUDIO_F32SYS; // 32-bit floating-point audio
  want.channels = 2; // Stereo output
  want.samples = 256; // Buffer size (64 samples per channel, 2 channels)
  want.callback = audio_callback;
  want.userdata = NULL;

  if (drb_api->SDL_OpenAudio(&want, &have) < 0) {
    printf("Could not open audio: %s\n", "");
    return;
  }
}