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BLI_math: add `isect_seg_seg_v3` function and use in the cloth collision algorith. 

In my tests a 4% improvement in performance was achieved by simulating a square cloth over the cube.
This commit is contained in:
Germano Cavalcante 2018-10-01 00:16:44 -03:00
parent 1f2c4f8809
commit 9df476ecaa
3 changed files with 75 additions and 37 deletions
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43
source/blender/blenkernel/intern/collision.c
View File

@ -192,36 +192,6 @@ void bvhtree_update_from_mvert(
Collision modifier code end
***********************************/
static void clamp_point_seg(float a[3], float b[3], float p[3])
{
float ap[3], bp[3], ab[3];
sub_v3_v3v3(ap, p, a);
sub_v3_v3v3(bp, p, b);
sub_v3_v3v3(ab, b, a);
if (dot_v3v3(ap, bp) > 0.0f) {
if (dot_v3v3(ap, ab) > 0.0f) {
copy_v3_v3(p, b);
}
else {
copy_v3_v3(p, a);
}
}
}
static bool isect_seg_seg(float a1[3], float a2[3], float b1[3], float b2[3], float r_a[3], float r_b[3])
{
if (isect_line_line_epsilon_v3(a1, a2, b1, b2, r_a, r_b, 0.0f)) {
clamp_point_seg(a1, a2, r_a);
clamp_point_seg(b1, b2, r_b);
return true;
}
return false;
}
BLI_INLINE int next_ind(int i)
{
return (++i < 3) ? i : 0;
@ -410,14 +380,13 @@ static float compute_collision_point(float a1[3], float a2[3], float a3[3], floa
if (isect_count == 0) {
for (int i = 0; i < 3; i++) {
for (int j = 0; j < 3; j++) {
if (isect_seg_seg(a[i], a[next_ind(i)], b[j], b[next_ind(j)], tmp_co1, tmp_co2)) {
tmp = len_squared_v3v3(tmp_co1, tmp_co2);
isect_seg_seg_v3(a[i], a[next_ind(i)], b[j], b[next_ind(j)], tmp_co1, tmp_co2);
tmp = len_squared_v3v3(tmp_co1, tmp_co2);
if (tmp < dist) {
dist = tmp;
copy_v3_v3(r_a, tmp_co1);
copy_v3_v3(r_b, tmp_co2);
}
if (tmp < dist) {
dist = tmp;
copy_v3_v3(r_a, tmp_co1);
copy_v3_v3(r_b, tmp_co2);
}
}
}

5
source/blender/blenlib/BLI_math_geom.h
View File

@ -207,6 +207,11 @@ void limit_dist_v3(float v1[3], float v2[3], const float dist);
#define ISECT_LINE_LINE_CROSS 2
int isect_seg_seg_v2(const float a1[2], const float a2[2], const float b1[2], const float b2[2]);
void isect_seg_seg_v3(
const float a0[3], const float a1[3],
const float b0[3], const float b1[3],
float r_a[3], float r_b[3]);
int isect_seg_seg_v2_int(const int a1[2], const int a2[2], const int b1[2], const int b2[2]);
int isect_seg_seg_v2_point_ex(
const float v0[2], const float v1[2], const float v2[2], const float v3[2], const float endpoint_bias,

64
source/blender/blenlib/intern/math_geom.c
View File

@ -1123,6 +1123,70 @@ int isect_seg_seg_v2(const float v1[2], const float v2[2], const float v3[2], co
return ISECT_LINE_LINE_NONE;
}
/* Returns a point on each segment that is closest to the other. */
void isect_seg_seg_v3(
const float a0[3], const float a1[3],
const float b0[3], const float b1[3],
float r_a[3], float r_b[3])
{
float fac_a, fac_b;
float a_dir[3], b_dir[3], a0b0[3], crs_ab[3];
sub_v3_v3v3(a_dir, a1, a0);
sub_v3_v3v3(b_dir, b1, b0);
sub_v3_v3v3(a0b0, b0, a0);
cross_v3_v3v3(crs_ab, b_dir, a_dir);
const float nlen = len_squared_v3(crs_ab);
if (nlen == 0.0f) {
/* Parallel Lines */
/* In this case return any point that
* is between the closest segments. */
float a0b1[3], a1b0[3], len_a, len_b, fac1, fac2;
sub_v3_v3v3(a0b1, b1, a0);
sub_v3_v3v3(a1b0, b0, a1);
len_a = len_squared_v3(a_dir);
len_b = len_squared_v3(b_dir);
if (len_a) {
fac1 = dot_v3v3(a0b0, a_dir);
fac2 = dot_v3v3(a0b1, a_dir);
CLAMP(fac1, 0.0f, len_a);
CLAMP(fac2, 0.0f, len_a);
fac_a = (fac1 + fac2) / (2 * len_a);
}
else {
fac_a = 0.0f;
}
if (len_b) {
fac1 = -dot_v3v3(a0b0, b_dir);
fac2 = -dot_v3v3(a1b0, b_dir);
CLAMP(fac1, 0.0f, len_b);
CLAMP(fac2, 0.0f, len_b);
fac_b = (fac1 + fac2) / (2 * len_b);
}
else {
fac_b = 0.0f;
}
}
else {
float c[3], cray[3];
sub_v3_v3v3(c, crs_ab, a0b0);
cross_v3_v3v3(cray, c, b_dir);
fac_a = dot_v3v3(cray, crs_ab) / nlen;
cross_v3_v3v3(cray, c, a_dir);
fac_b = dot_v3v3(cray, crs_ab) / nlen;
CLAMP(fac_a, 0.0f, 1.0f);
CLAMP(fac_b, 0.0f, 1.0f);
}
madd_v3_v3v3fl(r_a, a0, a_dir, fac_a);
madd_v3_v3v3fl(r_b, b0, b_dir, fac_b);
}
/**
* Get intersection point of two 2D segments.
*