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/* SPDX-License-Identifier: GPL-2.0-or-later
* Copyright 2001-2002 NaN Holding BV. All rights reserved. */
/** \file
* \ingroup bli
* \brief Jitter offset table
*/
#include "MEM_guardedalloc.h"
#include <math.h>
#include <string.h>
#include "BLI_jitter_2d.h"
#include "BLI_rand.h"
#include "BLI_strict_flags.h"
void BLI_jitterate1(float (*jit1)[2], float (*jit2)[2], int num, float radius1)
{
int i, j, k;
float vecx, vecy, dvecx, dvecy, x, y, len;
for (i = num - 1; i >= 0; i--) {
dvecx = dvecy = 0.0;
x = jit1[i][0];
y = jit1[i][1];
for (j = num - 1; j >= 0; j--) {
if (i != j) {
vecx = jit1[j][0] - x - 1.0f;
vecy = jit1[j][1] - y - 1.0f;
for (k = 3; k > 0; k--) {
if (fabsf(vecx) < radius1 && fabsf(vecy) < radius1) {
len = sqrtf(vecx * vecx + vecy * vecy);
if (len > 0 && len < radius1) {
len = len / radius1;
dvecx += vecx / len;
dvecy += vecy / len;
}
}
vecx += 1.0f;
if (fabsf(vecx) < radius1 && fabsf(vecy) < radius1) {
len = sqrtf(vecx * vecx + vecy * vecy);
if (len > 0 && len < radius1) {
len = len / radius1;
dvecx += vecx / len;
dvecy += vecy / len;
}
}
vecx += 1.0f;
if (fabsf(vecx) < radius1 && fabsf(vecy) < radius1) {
len = sqrtf(vecx * vecx + vecy * vecy);
if (len > 0 && len < radius1) {
len = len / radius1;
dvecx += vecx / len;
dvecy += vecy / len;
}
}
vecx -= 2.0f;
vecy += 1.0f;
}
}
}
x -= dvecx / 18.0f;
y -= dvecy / 18.0f;
x -= floorf(x);
y -= floorf(y);
jit2[i][0] = x;
jit2[i][1] = y;
}
memcpy(jit1, jit2, 2 * (unsigned int)num * sizeof(float));
}
void BLI_jitterate2(float (*jit1)[2], float (*jit2)[2], int num, float radius2)
{
int i, j;
float vecx, vecy, dvecx, dvecy, x, y;
for (i = num - 1; i >= 0; i--) {
dvecx = dvecy = 0.0;
x = jit1[i][0];
y = jit1[i][1];
for (j = num - 1; j >= 0; j--) {
if (i != j) {
vecx = jit1[j][0] - x - 1.0f;
vecy = jit1[j][1] - y - 1.0f;
if (fabsf(vecx) < radius2) {
dvecx += vecx * radius2;
}
vecx += 1.0f;
if (fabsf(vecx) < radius2) {
dvecx += vecx * radius2;
}
vecx += 1.0f;
if (fabsf(vecx) < radius2) {
dvecx += vecx * radius2;
}
if (fabsf(vecy) < radius2) {
dvecy += vecy * radius2;
}
vecy += 1.0f;
if (fabsf(vecy) < radius2) {
dvecy += vecy * radius2;
}
vecy += 1.0f;
if (fabsf(vecy) < radius2) {
dvecy += vecy * radius2;
}
}
}
x -= dvecx / 2.0f;
y -= dvecy / 2.0f;
x -= floorf(x);
y -= floorf(y);
jit2[i][0] = x;
jit2[i][1] = y;
}
memcpy(jit1, jit2, (unsigned int)num * sizeof(float[2]));
}
void BLI_jitter_init(float (*jitarr)[2], int num)
{
float(*jit2)[2];
float number_fl, number_fl_sqrt;
float x, rad1, rad2, rad3;
RNG *rng;
int i;
if (num == 0) {
return;
}
number_fl = (float)num;
number_fl_sqrt = sqrtf(number_fl);
jit2 = MEM_mallocN(12 + (unsigned int)num * sizeof(float[2]), "initjit");
rad1 = 1.0f / number_fl_sqrt;
rad2 = 1.0f / number_fl;
rad3 = number_fl_sqrt / number_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 / number_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 jitter to be centered around (0, 0). */
for (i = 0; i < num; i++) {
jitarr[i][0] -= 0.5f;
jitarr[i][1] -= 0.5f;
}
}
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