#include <math.h>
#include <stdio.h>
#include <stdlib.h>

#define PI 3.141592653589793
#define HZ 500
#define OCTAVES 8
#define SAMPLERATE 48000
#define N (OCTAVES * SAMPLERATE)

float f[16][N];
float t[N];

int main()
{
  for (int j = 0; j < 16; ++j)
  {
    double js = j / 3.0;
    double w = ceil(js) + 1;
    for (int i = 0; i < N; ++i)
    {
      t[i] = i + js * rand() / (double) RAND_MAX;
      f[0][i] = sin(2 * PI * exp(log(HZ << OCTAVES) * t[i] / N + (1 - t[i] / N) * log(HZ)));
    }
    for (int i = 0; i < N; ++i)
    {
      double s = 0;
      double r = 0;
      for (int ii = i - w; ii <= i + w; ++ii)
      {
        if (ii < 0 || N <= ii) continue;
        double dt = t[i] - ii;
        double hat = fmax(1 - fabs(dt / w), 0);
        s += hat * f[0][ii];
        r += hat;
      }
      f[j][i] = s / r;
    }
  }
  for (int i = 0; i < N; ++i)
  {
    t[i] = i;
    f[0][i] = sin(2 * PI * exp(log(HZ << OCTAVES) * t[i] / N + (1 - t[i] / N) * log(HZ)));
  }
  FILE *o = fopen("sweep.raw", "wb");
  fwrite(f, sizeof(f), 1, o);
  fclose(o);
  return 0;
}