blender
/
blender
136
406
Fork 589
Code Issues 6.2k Pull Requests 750 Projects 19 Wiki Activity

Fix T48167: Mesh select random factor is not accurate 

Selecting random percentage would not reliably guarantee the precise
percentage of selected elements now randomize an index array instead
and use the precise number of elements from this array.

Note that this change has only been made to edit-mesh
and should be applied to all random selection operators.
This commit is contained in:
Philipp Oeser 2021-04-06 14:30:44 +10:00 committed by Campbell Barton
parent 3f3b4745b6
commit 9c20228128
Notes: blender-bot 2023-05-29 09:17:12 +02:00 
Referenced by commit 98cd0fed36, Fix edit-mesh random select regression in random seed use
Referenced by issue #87228, Apply random selection factor precisely for all operators
Referenced by issue #48167, bpy.ops.mesh.select_random() not accurate
1 changed files with 31 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

41
source/blender/editors/mesh/editmesh_select.c
View File

@ -4632,35 +4632,56 @@ static int edbm_select_random_exec(bContext *C, wmOperator *op)
seed_iter += BLI_ghashutil_strhash_p(obedit->id.name);
}
RNG *rng = BLI_rng_new_srandom(seed_iter);
if (em->selectmode & SCE_SELECT_VERTEX) {
int elem_map_len = 0;
BMVert **elem_map = MEM_mallocN(sizeof(*elem_map) * em->bm->totvert, __func__);
BMVert *eve;
BM_ITER_MESH (eve, &iter, em->bm, BM_VERTS_OF_MESH) {
if (!BM_elem_flag_test(eve, BM_ELEM_HIDDEN) && BLI_rng_get_float(rng) < randfac) {
BM_vert_select_set(em->bm, eve, select);
if (!BM_elem_flag_test(eve, BM_ELEM_HIDDEN)) {
elem_map[elem_map_len++] = eve;
}
}
BLI_array_randomize(elem_map, sizeof(*elem_map), elem_map_len, seed);
const int count_select = elem_map_len * randfac;
for (int i = 0; i < count_select; i++) {
BM_vert_select_set(em->bm, elem_map[i], select);
}
MEM_freeN(elem_map);
}
else if (em->selectmode & SCE_SELECT_EDGE) {
int elem_map_len = 0;
BMEdge **elem_map = MEM_mallocN(sizeof(*elem_map) * em->bm->totedge, __func__);
BMEdge *eed;
BM_ITER_MESH (eed, &iter, em->bm, BM_EDGES_OF_MESH) {
if (!BM_elem_flag_test(eed, BM_ELEM_HIDDEN) && BLI_rng_get_float(rng) < randfac) {
BM_edge_select_set(em->bm, eed, select);
if (!BM_elem_flag_test(eed, BM_ELEM_HIDDEN)) {
elem_map[elem_map_len++] = eed;
}
}
BLI_array_randomize(elem_map, sizeof(*elem_map), elem_map_len, seed);
const int count_select = elem_map_len * randfac;
for (int i = 0; i < count_select; i++) {
BM_edge_select_set(em->bm, elem_map[i], select);
}
MEM_freeN(elem_map);
}
else {
int elem_map_len = 0;
BMFace **elem_map = MEM_mallocN(sizeof(*elem_map) * em->bm->totface, __func__);
BMFace *efa;
BM_ITER_MESH (efa, &iter, em->bm, BM_FACES_OF_MESH) {
if (!BM_elem_flag_test(efa, BM_ELEM_HIDDEN) && BLI_rng_get_float(rng) < randfac) {
BM_face_select_set(em->bm, efa, select);
if (!BM_elem_flag_test(efa, BM_ELEM_HIDDEN)) {
elem_map[elem_map_len++] = efa;
}
}
BLI_array_randomize(elem_map, sizeof(*elem_map), elem_map_len, seed);
const int count_select = elem_map_len * randfac;
for (int i = 0; i < count_select; i++) {
BM_face_select_set(em->bm, elem_map[i], select);
}
MEM_freeN(elem_map);
}
BLI_rng_free(rng);
if (select) {
/* was EDBM_select_flush, but it over select in edge/face mode */
EDBM_selectmode_flush(em);