void BLI_jitter_init(float (*jitarr)[2], int num)
{
float (*jit2)[2];
float num_fl, num_fl_sqrt;
float x, rad1, rad2, rad3;
RNG *rng;
int i;
if (num == 0) {
return;
}
num_fl = (float)num;
num_fl_sqrt = sqrtf(num_fl);
jit2 = MEM_mallocN(12 + (unsigned int)num * sizeof(float[2]), "initjit");
rad1 = 1.0f / num_fl_sqrt;
rad2 = 1.0f / num_fl;
rad3 = num_fl_sqrt / num_fl;
rng = BLI_rng_new(31415926 + (unsigned int)num);
x = 0;
for (i = 0; i < num; i++) {
jitarr[i][0] = x + rad1 * (float)(0.5 - BLI_rng_get_double(rng));
jitarr[i][1] = (float)i / num_fl + rad1 * (float)(0.5 - BLI_rng_get_double(rng));
x += rad3;
x -= floorf(x);
}
BLI_rng_free(rng);
for (i = 0; i < 24; i++) {
BLI_jitterate1(jitarr, jit2, num, rad1);
BLI_jitterate1(jitarr, jit2, num, rad1);
BLI_jitterate2(jitarr, jit2, num, rad2);
}
MEM_freeN(jit2);
/* finally, move jittertab to be centered around (0, 0) */
for (i = 0; i < num; i++) {
jitarr[i][0] -= 0.5f;
jitarr[i][1] -= 0.5f;
}
}
/* modified copy from rayshade.c */
static void hammersley_create(float *out, int n, int seed, float amount)
{
RNG *rng;
double p, t, offs[2];
int k, kk;
rng = BLI_rng_new(31415926 + n + seed);
offs[0] = BLI_rng_get_double(rng) + (double)amount;
offs[1] = BLI_rng_get_double(rng) + (double)amount;
BLI_rng_free(rng);
for (k = 0; k < n; k++) {
t = 0;
for (p = 0.5, kk = k; kk; p *= 0.5, kk >>= 1)
if (kk & 1) /* kk mod 2 = 1 */
t += p;
out[2*k + 0] = fmod((double)k/(double)n + offs[0], 1.0);
out[2*k + 1] = fmod(t + offs[1], 1.0);
}
}
