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#include <time.h>
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>
#include "fft.h"
#define N_SAMPLES 512
#define K ((2 * M_PI) / N_SAMPLES)
static double
ssin (double f)
{
return 0.5 * (sin (K * f) + 1.0);
}
static double
scos (double f)
{
return 0.5 * (cos (K * f) + 1.0);
}
int
main ()
{
complex_t *noise = malloc (sizeof (complex_t) * N_SAMPLES * N_SAMPLES);
int i, j;
double max, min;
srand48 (time (0));
for (i = 0; i < N_SAMPLES; ++i)
{
for (j = 0; j < N_SAMPLES; ++j)
{
#if 0
noise[i * N_SAMPLES + j].re = 0.6 * (drand48() + drand48()) - 0.2 * drand48();
#endif
noise[i * N_SAMPLES + j].im = 0;
noise[i * N_SAMPLES + j].re = 0.5 * (drand48() + drand48());
noise[i * N_SAMPLES + j].re = 0.6 * (drand48() + drand48()) - 0.2 * drand48();
}
}
fft_2d (noise, N_SAMPLES);
shift_2d (noise, N_SAMPLES);
max = noise[0].re;
min = noise[0].re;
for (i = 0; i < N_SAMPLES; ++i)
{
for (j = 0; j < N_SAMPLES; ++j)
{
double d = sqrt ((i - N_SAMPLES/2) * (i - N_SAMPLES/2) +
(j - N_SAMPLES/2) * (j - N_SAMPLES/2));
double f = (d / (N_SAMPLES)); // * (d / N_SAMPLES);
if (d != 0.0)
{
double factor = 0;
#define CHECK(n) \
((i <= (n) || i >= N_SAMPLES - ((n) + 1)) ^ \
(j <= (n) || j >= N_SAMPLES - ((n) + 1)))
#if 0
if (CHECK(1))
{
factor = 1;
}
else if (CHECK(42))
{
factor = 1;
}
else
{
factor = 0.1;
}
#endif
if (f <= 0.5)
{
factor = 0.5 * (cos (M_PI * (1 - 2 * (f))) + 1.0);
}
else
{
factor = 1;
}
#if 0
noise[i * N_SAMPLES + j].re *= 2.4 * f;
noise[i * N_SAMPLES + j].im *= 2.4 * f;
#endif
#if 0
if (f < 0.4)
factor = 0;
else
factor = 12 * (f - 0.4);
#endif
noise[i * N_SAMPLES + j].re *= factor;
noise[i * N_SAMPLES + j].im *= factor; // 8 * N_SAMPLES * N_SAMPLES * factor;
}
}
}
printf ("%f %f\n", noise[i * (N_SAMPLES/2) + N_SAMPLES/2].re, noise[i * (N_SAMPLES/2) + N_SAMPLES/2].im);
shift_2d (noise, N_SAMPLES);
ifft_2d (noise, N_SAMPLES);
#define N_BUCKETS 128
int hist[N_BUCKETS];
int bad;
bad = 0;
memset (hist, 0, sizeof hist);
for (i = 0; i < N_SAMPLES * N_SAMPLES; ++i)
{
int v = (noise[i].re * N_BUCKETS);
if (v == N_BUCKETS)
v = N_BUCKETS - 1;
else if (v >= N_BUCKETS || v < 0)
{
printf ("bad: %f (%d)\n", noise[i].re, v);
bad++;
}
else
hist[v]++;
}
int total = 0;
for (i = 0; i < N_BUCKETS; ++i)
{
printf ("%d: %d\n", i, hist[i]);
total += hist[i];
}
printf ("bad: %d (%f %%)\n", bad, 100.0 * bad / (N_SAMPLES * N_SAMPLES));
printf ("total: %d \n", total + bad);
show_image ("blue noise", noise, N_SAMPLES);
return 0;
}
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