synth_keys.c

#include "demo_common.h"

static const uint8_t scale[]  = {36, 38, 40, 43, 45, 60, 50, 52};
static const uint8_t scale2[] = {33, 31, 26, 31, 29, 33, 31, 29};

static CT_Smush rnd;

static void init_voice(CTSS_Synth *synth, CTSS_DSPStack *stack, float freq);
static int render_synth(const void *in,
                        void *out,
                        unsigned long frames,
                        const PaStreamCallbackTimeInfo *timeInfo,
                        PaStreamCallbackFlags status,
                        void *data);
static void trigger_note(AppState *app, char ch);

int main(int argc, char *argv[]) {
  AppState app;

  ct_smush_init(&rnd, 0xdecafbad);
  ctss_init(&app.synth, 8);

  ctss_add_global_lfo(&app.synth, ctss_osc("lfo1", ctss_process_osc_sin, 0.0f,
                                           HZ_TO_RAD(0.1f), 0.5f, 1.0f));

  for (uint8_t i = 0; i < app.synth.numStacks; i++) {
    init_voice(&app.synth, &app.synth.stacks[i], ctss_notes[scale[0]]);
  }

  app.pitch     = 28;
  app.callback  = render_synth;
  app.handler   = trigger_note;
  app.channels  = 1;
  app.isNewNote = 0;

  return demo(&app);
}

static void init_voice(CTSS_Synth *synth, CTSS_DSPStack *stack, float freq) {
  ctss_init_stack(stack);
  CTSS_DSPNode *env = ctss_adsr("env", synth->lfo[0]);
  ctss_configure_adsr(env, 2.0f, 0.7f, 1.5f, 0.5f, 0.5f, true);
  CTSS_DSPNode *lfo = ctss_osc("lfoPitch", ctss_process_osc_square, 0.0f,
                               HZ_TO_RAD(2.0f), HZ_TO_RAD(1.0f), 0.0f);
  CTSS_DSPNode *lfo2 = ctss_osc("lfoGain", ctss_process_osc_saw, 0.0f,
                                HZ_TO_RAD(6.666666f), 0.4f, 0.6f);
  CTSS_DSPNode *osc1 = ctss_osc("osc1", ctss_process_osc_saw, 0.0f,
                                HZ_TO_RAD(freq * 0.51f), 0.35f, 0.0f);
  ctss_set_osc_lfo(osc1, lfo, 1.0f);
  CTSS_DSPNode *osc2 = ctss_osc("osc2", ctss_process_osc_saw, 0.0f,
                                HZ_TO_RAD(freq), 0.35f, 0.0f);
  ctss_set_osc_lfo(osc2, lfo, 1.0f);
  ctss_set_osc_env(osc2, env, HZ_TO_RAD(10.0f));
  CTSS_DSPNode *sum  = ctss_op4("sum", osc1, env, osc2, env, ctss_process_madd);
  CTSS_DSPNode *gate = ctss_op2("gate", sum, lfo2, ctss_process_mult);
  // CTSS_DSPNode *filter = ctss_filter_iir("filter", IIR_LP, gate, NULL,
  // ct_smush_minmax(&rnd, 300.0f, 1200.0f),
  //                  0.85f);
  CTSS_DSPNode *filter =
      ctss_filter_formant("filter", ct_smush(&rnd) % 5, gate);
  CTSS_DSPNode *delay = ctss_delay("delay", filter, SAMPLE_RATE >> 2, 0.4f, 1);
  CTSS_DSPNode *filter2 =
      ctss_filter_iir("filter2", IIR_HP, delay, NULL, 1800.0f, 0.0f);
  CTSS_DSPNode *delay2 =
      ctss_delay("delay2", filter2, (uint32_t)(SAMPLE_RATE * 0.333f), 0.4, 1);
  CTSS_DSPNode *delay3 =
      ctss_delay("delay3", delay2, (uint32_t)(SAMPLE_RATE * 0.4781f), 0.4f, 1);
  CTSS_DSPNode *sum2 = ctss_op4_const("sum2", filter, 0.2f, delay3, 0.8f,
                                      ctss_process_madd_const);
  CTSS_DSPNode *nodes[] = {env,    lfo,   lfo2,    osc1,   osc2,   sum, gate,
                           filter, delay, filter2, delay2, delay3, sum2};
  ctss_build_stack(stack, nodes, 13);
}

static int render_synth(const void *in,
                        void *out,
                        unsigned long frames,
                        const PaStreamCallbackTimeInfo *timeInfo,
                        PaStreamCallbackFlags status,
                        void *data) {
  AppState *app = (AppState *)data;
  if (app->isNewNote) {
    float freq       = ctss_notes[scale[app->noteID % 8]];
    float freq2      = ctss_notes[scale2[(app->noteID % 8)] + 12];
    CTSS_DSPStack *s = &app->synth.stacks[app->voiceID];
    ctss_reset_adsr(NODE_ID(s, "env"));
    NODE_ID_STATE(CTSS_OscState, s, "osc1")->freq = HZ_TO_RAD(freq2);
    NODE_ID_STATE(CTSS_OscState, s, "osc2")->freq = HZ_TO_RAD(freq);
    ctss_activate_stack(s);
    app->noteID++;
    app->voiceID   = (app->voiceID + 1) % app->synth.numStacks;
    app->isNewNote = 0;
  }

  ctss_update_mix_mono_f32(&app->synth, ctss_mixdown_f32, frames, (float *)out);
  return 0;
}

static void trigger_note(AppState *app, char ch) {
  app->isNewNote = 1;
}