src/main.cc


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#include "audio/audio.h"
#include "audio/synth.h"
#include "gpu/gpu.h"
#include "platform.h"
#include "util/math.h"
#include <math.h>
#include <string.h>

#define DEMO_BPM 120.0f
#define SECONDS_PER_BEAT (60.0f / DEMO_BPM)
#define SPEC_FRAMES 16

static float g_spec_buffer_a[SPEC_FRAMES * DCT_SIZE];
static float g_spec_buffer_b[SPEC_FRAMES * DCT_SIZE];

void generate_tone(float *buffer, float freq) {
  memset(buffer, 0, SPEC_FRAMES * DCT_SIZE * sizeof(float));
  for (int frame = 0; frame < SPEC_FRAMES; ++frame) {
    float *spec_frame = buffer + frame * DCT_SIZE;
    float amplitude = powf(1.0f - (float)frame / SPEC_FRAMES, 2.0f);

    int bin = (int)(freq / (32000.0f / 2.0f) * DCT_SIZE);
    if (bin > 0 && bin < DCT_SIZE) {
      spec_frame[bin] = amplitude;
    }
  }
}

int main() {
  platform_init();
  gpu_init(platform_get_window());
  audio_init();

  generate_tone(g_spec_buffer_a, 440.0f); // A4
  generate_tone(g_spec_buffer_b, 880.0f); // A5

  Spectrogram spec = {g_spec_buffer_a, g_spec_buffer_b, SPEC_FRAMES};
  int tone_id = synth_register_spectrogram(&spec);

  double last_beat_time = 0.0;
  int beat_count = 0;

  while (!platform_should_close()) {
    platform_poll();

    double current_time = platform_get_time();
    if (current_time - last_beat_time > SECONDS_PER_BEAT) {
      synth_trigger_voice(tone_id, 0.5f, 0.0f);
      last_beat_time = current_time;
      beat_count++;

      if (beat_count == 8) {
        // Time to update the sound!
        float *back_buffer = synth_begin_update(tone_id);
        if (back_buffer) {
          generate_tone(back_buffer, 220.0f); // A3
          synth_commit_update(tone_id);
        }
      }
    }

    gpu_draw();
    audio_update();
  }

  audio_shutdown();
  gpu_shutdown();
  platform_shutdown();
  return 0;
}