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ee8b284d117385168739ee9f6f459e077af2ec8c
blender-archive/source/blender/bmesh/intern/bmesh_mods.c
Leon Zandman c317f111c1 Cleanup: Spelling Mistakes 
This patch fixes many minor spelling mistakes, all in comments or
console output. Mostly contractions like can't, won't, don't, its/it's,
etc.

Differential Revision: https://developer.blender.org/D11663

Reviewed by Harley Acheson
2021-06-22 10:54:50 -07:00

1111 lines
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/*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
/** \file
* \ingroup bmesh
*
* This file contains functions for locally modifying
* the topology of existing mesh data. (split, join, flip etc).
*/
#include "MEM_guardedalloc.h"
#include "BLI_array.h"
#include "BLI_math.h"
#include "BKE_customdata.h"
#include "bmesh.h"
#include "intern/bmesh_private.h"
/**
* \brief Dissolve Vert
*
* Turns the face region surrounding a manifold vertex into a single polygon.
*
* \par Example:
* <pre>
* +---------+ +---------+
* | \ / | | |
* Before: | v | After: | |
* | / \ | | |
* +---------+ +---------+
* </pre>
*
* This function can also collapse edges too
* in cases when it can't merge into faces.
*
* \par Example:
* <pre>
* Before: +----v----+ After: +---------+
* </pre>
*
* \note dissolves vert, in more situations than BM_disk_dissolve
* (e.g. if the vert is part of a wire edge, etc).
*/
bool BM_vert_dissolve(BMesh *bm, BMVert *v)
{
/* logic for 3 or more is identical */
const int len = BM_vert_edge_count_at_most(v, 3);
if (len == 1) {
BM_vert_kill(bm, v); /* will kill edges too */
return true;
}
if (!BM_vert_is_manifold(v)) {
if (!v->e) {
BM_vert_kill(bm, v);
return true;
}
if (!v->e->l) {
if (len == 2) {
return (BM_vert_collapse_edge(bm, v->e, v, true, true, true) != NULL);
}
/* used to kill the vertex here, but it may be connected to faces.
* so better do nothing */
return false;
}
return false;
}
if (len == 2 && BM_vert_face_count_is_equal(v, 1)) {
/* boundary vertex on a face */
return (BM_vert_collapse_edge(bm, v->e, v, true, true, true) != NULL);
}
return BM_disk_dissolve(bm, v);
}
/**
* dissolves all faces around a vert, and removes it.
*/
bool BM_disk_dissolve(BMesh *bm, BMVert *v)
{
BMEdge *e, *keepedge = NULL, *baseedge = NULL;
int len = 0;
if (!BM_vert_is_manifold(v)) {
return false;
}
if (v->e) {
/* v->e we keep, what else */
e = v->e;
do {
e = bmesh_disk_edge_next(e, v);
if (!(BM_edge_share_face_check(e, v->e))) {
keepedge = e;
baseedge = v->e;
break;
}
len++;
} while (e != v->e);
}
/* this code for handling 2 and 3-valence verts
* may be totally bad */
if (keepedge == NULL && len == 3) {
#if 0
/* handle specific case for three-valence. solve it by
* increasing valence to four. this may be hackish. . */
BMLoop *l_a = BM_face_vert_share_loop(e->l->f, v);
BMLoop *l_b = (e->l->v == v) ? e->l->next : e->l;
if (!BM_face_split(bm, e->l->f, l_a, l_b, NULL, NULL, false)) {
return false;
}
if (!BM_disk_dissolve(bm, v)) {
return false;
}
#else
if (UNLIKELY(!BM_faces_join_pair(bm, e->l, e->l->radial_next, true))) {
return false;
}
if (UNLIKELY(!BM_vert_collapse_faces(bm, v->e, v, 1.0, true, false, true, true))) {
return false;
}
#endif
return true;
}
if (keepedge == NULL && len == 2) {
/* collapse the vertex */
e = BM_vert_collapse_faces(bm, v->e, v, 1.0, true, true, true, true);
if (!e) {
return false;
}
/* handle two-valence */
if (e->l != e->l->radial_next) {
if (!BM_faces_join_pair(bm, e->l, e->l->radial_next, true)) {
return false;
}
}
return true;
}
if (keepedge) {
bool done = false;
while (!done) {
done = true;
e = v->e;
do {
BMFace *f = NULL;
if (BM_edge_is_manifold(e) && (e != baseedge) && (e != keepedge)) {
f = BM_faces_join_pair(bm, e->l, e->l->radial_next, true);
/* return if couldn't join faces in manifold
* conditions */
/* !disabled for testing why bad things happen */
if (!f) {
return false;
}
}
if (f) {
done = false;
break;
}
} while ((e = bmesh_disk_edge_next(e, v)) != v->e);
}
/* collapse the vertex */
/* note, the baseedge can be a boundary of manifold, use this as join_faces arg */
e = BM_vert_collapse_faces(
bm, baseedge, v, 1.0, true, !BM_edge_is_boundary(baseedge), true, true);
if (!e) {
return false;
}
if (e->l) {
/* get remaining two faces */
if (e->l != e->l->radial_next) {
/* join two remaining faces */
if (!BM_faces_join_pair(bm, e->l, e->l->radial_next, true)) {
return false;
}
}
}
}
return true;
}
/**
* \brief Faces Join Pair
*
* Joins two adjacent faces together.
*
* \note This method calls to #BM_faces_join to do its work.
* This means connected edges which also share the two faces will be joined.
*
* If the windings do not match the winding of the new face will follow
* \a l_a's winding (i.e. \a l_b will be reversed before the join).
*
* \return The combined face or NULL on failure.
*/
BMFace *BM_faces_join_pair(BMesh *bm, BMLoop *l_a, BMLoop *l_b, const bool do_del)
{
BLI_assert((l_a != l_b) && (l_a->e == l_b->e));
if (l_a->v == l_b->v) {
const int cd_loop_mdisp_offset = CustomData_get_offset(&bm->ldata, CD_MDISPS);
bmesh_kernel_loop_reverse(bm, l_b->f, cd_loop_mdisp_offset, true);
}
BMFace *faces[2] = {l_a->f, l_b->f};
return BM_faces_join(bm, faces, 2, do_del);
}
/**
* \brief Face Split
*
* Split a face along two vertices. returns the newly made face, and sets
* the \a r_l member to a loop in the newly created edge.
*
* \param bm: The bmesh
* \param f: the original face
* \param l_a, l_b: Loops of this face, their vertices define
* the split edge to be created (must be differ and not can't be adjacent in the face).
* \param r_l: pointer which will receive the BMLoop for the split edge in the new face
* \param example: Edge used for attributes of splitting edge, if non-NULL
* \param no_double: Use an existing edge if found
*
* \return Pointer to the newly created face representing one side of the split
* if the split is successful (and the original original face will be the
* other side). NULL if the split fails.
*/
BMFace *BM_face_split(BMesh *bm,
BMFace *f,
BMLoop *l_a,
BMLoop *l_b,
BMLoop **r_l,
BMEdge *example,
const bool no_double)
{
const int cd_loop_mdisp_offset = CustomData_get_offset(&bm->ldata, CD_MDISPS);
BMFace *f_new, *f_tmp;
BLI_assert(l_a != l_b);
BLI_assert(f == l_a->f && f == l_b->f);
BLI_assert(!BM_loop_is_adjacent(l_a, l_b));
/* could be an assert */
if (UNLIKELY(BM_loop_is_adjacent(l_a, l_b)) || UNLIKELY((f != l_a->f || f != l_b->f))) {
if (r_l) {
*r_l = NULL;
}
return NULL;
}
/* do we have a multires layer? */
if (cd_loop_mdisp_offset != -1) {
f_tmp = BM_face_copy(bm, bm, f, false, false);
}
#ifdef USE_BMESH_HOLES
f_new = bmesh_kernel_split_face_make_edge(bm, f, l_a, l_b, r_l, NULL, example, no_double);
#else
f_new = bmesh_kernel_split_face_make_edge(bm, f, l_a, l_b, r_l, example, no_double);
#endif
if (f_new) {
/* handle multires update */
if (cd_loop_mdisp_offset != -1) {
float f_dst_center[3];
float f_src_center[3];
BM_face_calc_center_median(f_tmp, f_src_center);
BM_face_calc_center_median(f, f_dst_center);
BM_face_interp_multires_ex(bm, f, f_tmp, f_dst_center, f_src_center, cd_loop_mdisp_offset);
BM_face_calc_center_median(f_new, f_dst_center);
BM_face_interp_multires_ex(
bm, f_new, f_tmp, f_dst_center, f_src_center, cd_loop_mdisp_offset);
#if 0
/* BM_face_multires_bounds_smooth doesn't flip displacement correct */
BM_face_multires_bounds_smooth(bm, f);
BM_face_multires_bounds_smooth(bm, f_new);
#endif
}
}
if (cd_loop_mdisp_offset != -1) {
BM_face_kill(bm, f_tmp);
}
return f_new;
}
/**
* \brief Face Split with intermediate points
*
* Like BM_face_split, but with an edge split by \a n intermediate points with given coordinates.
*
* \param bm: The bmesh.
* \param f: the original face.
* \param l_a, l_b: Vertices which define the split edge, must be different.
* \param cos: Array of coordinates for intermediate points.
* \param n: Length of \a cos (must be > 0).
* \param r_l: pointer which will receive the BMLoop.
* for the first split edge (from \a l_a) in the new face.
* \param example: Edge used for attributes of splitting edge, if non-NULL.
*
* \return Pointer to the newly created face representing one side of the split
* if the split is successful (and the original original face will be the
* other side). NULL if the split fails.
*/
BMFace *BM_face_split_n(BMesh *bm,
BMFace *f,
BMLoop *l_a,
BMLoop *l_b,
float cos[][3],
int n,
BMLoop **r_l,
BMEdge *example)
{
BMFace *f_new, *f_tmp;
BMLoop *l_new;
BMEdge *e, *e_new;
BMVert *v_new;
// BMVert *v_a = l_a->v; /* UNUSED */
BMVert *v_b = l_b->v;
int i, j;
BLI_assert(l_a != l_b);
BLI_assert(f == l_a->f && f == l_b->f);
BLI_assert(!((n == 0) && BM_loop_is_adjacent(l_a, l_b)));
/* could be an assert */
if (UNLIKELY((n == 0) && BM_loop_is_adjacent(l_a, l_b)) || UNLIKELY(l_a->f != l_b->f)) {
if (r_l) {
*r_l = NULL;
}
return NULL;
}
f_tmp = BM_face_copy(bm, bm, f, true, true);
#ifdef USE_BMESH_HOLES
f_new = bmesh_kernel_split_face_make_edge(bm, f, l_a, l_b, &l_new, NULL, example, false);
#else
f_new = bmesh_kernel_split_face_make_edge(bm, f, l_a, l_b, &l_new, example, false);
#endif
/* bmesh_kernel_split_face_make_edge returns in 'l_new'
* a Loop for f_new going from 'v_a' to 'v_b'.
* The radial_next is for 'f' and goes from 'v_b' to 'v_a' */
if (f_new) {
e = l_new->e;
for (i = 0; i < n; i++) {
v_new = bmesh_kernel_split_edge_make_vert(bm, v_b, e, &e_new);
BLI_assert(v_new != NULL);
/* bmesh_kernel_split_edge_make_vert returns in 'e_new'
* the edge going from 'v_new' to 'v_b'. */
copy_v3_v3(v_new->co, cos[i]);
/* interpolate the loop data for the loops with (v == v_new), using orig face */
for (j = 0; j < 2; j++) {
BMEdge *e_iter = (j == 0) ? e : e_new;
BMLoop *l_iter = e_iter->l;
do {
if (l_iter->v == v_new) {
/* this interpolates both loop and vertex data */
BM_loop_interp_from_face(bm, l_iter, f_tmp, true, true);
}
} while ((l_iter = l_iter->radial_next) != e_iter->l);
}
e = e_new;
}
}
BM_face_verts_kill(bm, f_tmp);
if (r_l) {
*r_l = l_new;
}
return f_new;
}
/**
* \brief Vert Collapse Faces
*
* Collapses vertex \a v_kill that has only two manifold edges
* onto a vertex it shares an edge with.
* \a fac defines the amount of interpolation for Custom Data.
*
* \note that this is not a general edge collapse function.
*
* \note this function is very close to #BM_vert_collapse_edge,
* both collapse a vertex and return a new edge.
* Except this takes a factor and merges custom data.
*
* \param bm: The bmesh
* \param e_kill: The edge to collapse
* \param v_kill: The vertex to collapse into the edge
* \param fac: The factor along the edge
* \param join_faces: When true the faces around the vertex will be joined
* otherwise collapse the vertex by merging the 2 edges this vert touches into one.
* \param kill_degenerate_faces: Removes faces with less than 3 verts after collapsing.
*
* \returns The New Edge
*/
BMEdge *BM_vert_collapse_faces(BMesh *bm,
BMEdge *e_kill,
BMVert *v_kill,
float fac,
const bool do_del,
const bool join_faces,
const bool kill_degenerate_faces,
const bool kill_duplicate_faces)
{
BMEdge *e_new = NULL;
BMVert *tv = BM_edge_other_vert(e_kill, v_kill);
BMEdge *e2;
BMVert *tv2;
/* Only intended to be called for 2-valence vertices */
BLI_assert(bmesh_disk_count(v_kill) <= 2);
/* first modify the face loop data */
if (e_kill->l) {
BMLoop *l_iter;
const float w[2] = {1.0f - fac, fac};
l_iter = e_kill->l;
do {
if (l_iter->v == tv && l_iter->next->v == v_kill) {
const void *src[2];
BMLoop *tvloop = l_iter;
BMLoop *kvloop = l_iter->next;
src[0] = kvloop->head.data;
src[1] = tvloop->head.data;
CustomData_bmesh_interp(&bm->ldata, src, w, NULL, 2, kvloop->head.data);
}
} while ((l_iter = l_iter->radial_next) != e_kill->l);
}
/* now interpolate the vertex data */
BM_data_interp_from_verts(bm, v_kill, tv, v_kill, fac);
e2 = bmesh_disk_edge_next(e_kill, v_kill);
tv2 = BM_edge_other_vert(e2, v_kill);
if (join_faces) {
BMIter fiter;
BMFace **faces = NULL;
BMFace *f;
BLI_array_staticdeclare(faces, BM_DEFAULT_ITER_STACK_SIZE);
BM_ITER_ELEM (f, &fiter, v_kill, BM_FACES_OF_VERT) {
BLI_array_append(faces, f);
}
if (BLI_array_len(faces) >= 2) {
BMFace *f2 = BM_faces_join(bm, faces, BLI_array_len(faces), true);
if (f2) {
BMLoop *l_a, *l_b;
if ((l_a = BM_face_vert_share_loop(f2, tv)) && (l_b = BM_face_vert_share_loop(f2, tv2))) {
BMLoop *l_new;
if (BM_face_split(bm, f2, l_a, l_b, &l_new, NULL, false)) {
e_new = l_new->e;
}
}
}
}
BLI_assert(BLI_array_len(faces) < 8);
BLI_array_free(faces);
}
else {
/* single face or no faces */
/* same as BM_vert_collapse_edge() however we already
* have vars to perform this operation so don't call. */
e_new = bmesh_kernel_join_edge_kill_vert(
bm, e_kill, v_kill, do_del, true, kill_degenerate_faces, kill_duplicate_faces);
/* e_new = BM_edge_exists(tv, tv2); */ /* same as return above */
}
return e_new;
}
/**
* \brief Vert Collapse Faces
*
* Collapses a vertex onto another vertex it shares an edge with.
*
* \return The New Edge
*/
BMEdge *BM_vert_collapse_edge(BMesh *bm,
BMEdge *e_kill,
BMVert *v_kill,
const bool do_del,
const bool kill_degenerate_faces,
const bool kill_duplicate_faces)
{
/* nice example implementation but we want loops to have their customdata
* accounted for */
#if 0
BMEdge *e_new = NULL;
/* Collapse between 2 edges */
/* in this case we want to keep all faces and not join them,
* rather just get rid of the vertex - see bug T28645. */
BMVert *tv = BM_edge_other_vert(e_kill, v_kill);
if (tv) {
BMEdge *e2 = bmesh_disk_edge_next(e_kill, v_kill);
if (e2) {
BMVert *tv2 = BM_edge_other_vert(e2, v_kill);
if (tv2) {
/* only action, other calls here only get the edge to return */
e_new = bmesh_kernel_join_edge_kill_vert(
bm, e_kill, v_kill, do_del, true, kill_degenerate_faces);
}
}
}
return e_new;
#else
/* with these args faces are never joined, same as above
* but account for loop customdata */
return BM_vert_collapse_faces(
bm, e_kill, v_kill, 1.0f, do_del, false, kill_degenerate_faces, kill_duplicate_faces);
#endif
}
#undef DO_V_INTERP
/**
* Collapse and edge into a single vertex.
*/
BMVert *BM_edge_collapse(
BMesh *bm, BMEdge *e_kill, BMVert *v_kill, const bool do_del, const bool kill_degenerate_faces)
{
return bmesh_kernel_join_vert_kill_edge(bm, e_kill, v_kill, do_del, true, kill_degenerate_faces);
}
/**
* \brief Edge Split
*
* <pre>
* Before: v
* +-----------------------------------+
* e
*
* After: v v_new (returned)
* +-----------------+-----------------+
* r_e e
* </pre>
*
* \param e: The edge to split.
* \param v: One of the vertices in \a e and defines the "from" end of the splitting operation,
* the new vertex will be \a fac of the way from \a v to the other end.
* \param r_e: The newly created edge.
* \return The new vertex.
*/
BMVert *BM_edge_split(BMesh *bm, BMEdge *e, BMVert *v, BMEdge **r_e, float fac)
{
BMVert *v_new, *v_other;
BMEdge *e_new;
BMFace **oldfaces = NULL;
BLI_array_staticdeclare(oldfaces, 32);
const int cd_loop_mdisp_offset = BM_edge_is_wire(e) ?
-1 :
CustomData_get_offset(&bm->ldata, CD_MDISPS);
BLI_assert(BM_vert_in_edge(e, v) == true);
/* do we have a multi-res layer? */
if (cd_loop_mdisp_offset != -1) {
BMLoop *l;
int i;
l = e->l;
do {
BLI_array_append(oldfaces, l->f);
l = l->radial_next;
} while (l != e->l);
/* flag existing faces so we can differentiate oldfaces from new faces */
for (i = 0; i < BLI_array_len(oldfaces); i++) {
BM_ELEM_API_FLAG_ENABLE(oldfaces[i], _FLAG_OVERLAP);
oldfaces[i] = BM_face_copy(bm, bm, oldfaces[i], true, true);
BM_ELEM_API_FLAG_DISABLE(oldfaces[i], _FLAG_OVERLAP);
}
}
v_other = BM_edge_other_vert(e, v);
v_new = bmesh_kernel_split_edge_make_vert(bm, v, e, &e_new);
if (r_e != NULL) {
*r_e = e_new;
}
BLI_assert(v_new != NULL);
BLI_assert(BM_vert_in_edge(e_new, v) && BM_vert_in_edge(e_new, v_new));
BLI_assert(BM_vert_in_edge(e, v_new) && BM_vert_in_edge(e, v_other));
sub_v3_v3v3(v_new->co, v_other->co, v->co);
madd_v3_v3v3fl(v_new->co, v->co, v_new->co, fac);
e_new->head.hflag = e->head.hflag;
BM_elem_attrs_copy(bm, bm, e, e_new);
/* v->v_new->v2 */
BM_data_interp_face_vert_edge(bm, v_other, v, v_new, e, fac);
BM_data_interp_from_verts(bm, v, v_other, v_new, fac);
if (cd_loop_mdisp_offset != -1) {
int i, j;
/* interpolate new/changed loop data from copied old faces */
for (i = 0; i < BLI_array_len(oldfaces); i++) {
float f_center_old[3];
BM_face_calc_center_median(oldfaces[i], f_center_old);
for (j = 0; j < 2; j++) {
BMEdge *e1 = j ? e_new : e;
BMLoop *l;
l = e1->l;
if (UNLIKELY(!l)) {
BMESH_ASSERT(0);
break;
}
do {
/* check this is an old face */
if (BM_ELEM_API_FLAG_TEST(l->f, _FLAG_OVERLAP)) {
float f_center[3];
BM_face_calc_center_median(l->f, f_center);
BM_face_interp_multires_ex(
bm, l->f, oldfaces[i], f_center, f_center_old, cd_loop_mdisp_offset);
}
l = l->radial_next;
} while (l != e1->l);
}
}
/* destroy the old faces */
for (i = 0; i < BLI_array_len(oldfaces); i++) {
BM_face_verts_kill(bm, oldfaces[i]);
}
/* fix boundaries a bit, doesn't work too well quite yet */
#if 0
for (j = 0; j < 2; j++) {
BMEdge *e1 = j ? e_new : e;
BMLoop *l, *l2;
l = e1->l;
if (UNLIKELY(!l)) {
BMESH_ASSERT(0);
break;
}
do {
BM_face_multires_bounds_smooth(bm, l->f);
l = l->radial_next;
} while (l != e1->l);
}
#endif
BLI_array_free(oldfaces);
}
return v_new;
}
/**
* \brief Split an edge multiple times evenly
*
* \param r_varr: Optional array, verts in between (v1 -> v2)
*/
BMVert *BM_edge_split_n(BMesh *bm, BMEdge *e, int numcuts, BMVert **r_varr)
{
int i;
float percent;
BMVert *v_new = NULL;
for (i = 0; i < numcuts; i++) {
percent = 1.0f / (float)(numcuts + 1 - i);
v_new = BM_edge_split(bm, e, e->v2, NULL, percent);
if (r_varr) {
/* fill in reverse order (v1 -> v2) */
r_varr[numcuts - i - 1] = v_new;
}
}
return v_new;
}
/**
* Swap v1 & v2
*
* \note Typically we shouldn't care about this, however it's used when extruding wire edges.
*/
void BM_edge_verts_swap(BMEdge *e)
{
SWAP(BMVert *, e->v1, e->v2);
SWAP(BMDiskLink, e->v1_disk_link, e->v2_disk_link);
}
#if 0
/**
* Checks if a face is valid in the data structure
*/
bool BM_face_validate(BMFace *face, FILE *err)
{
BMIter iter;
BLI_array_declare(verts);
BMVert **verts = NULL;
BMLoop *l;
int i, j;
bool ret = true;
if (face->len == 2) {
fprintf(err, "warning: found two-edged face. face ptr: %p\n", face);
fflush(err);
}
BLI_array_grow_items(verts, face->len);
BM_ITER_ELEM_INDEX (l, &iter, face, BM_LOOPS_OF_FACE, i) {
verts[i] = l->v;
if (l->e->v1 == l->e->v2) {
fprintf(err, "Found bmesh edge with identical verts!\n");
fprintf(err, " edge ptr: %p, vert: %p\n", l->e, l->e->v1);
fflush(err);
ret = false;
}
}
for (i = 0; i < face->len; i++) {
for (j = 0; j < face->len; j++) {
if (j == i) {
continue;
}
if (verts[i] == verts[j]) {
fprintf(err, "Found duplicate verts in bmesh face!\n");
fprintf(err, " face ptr: %p, vert: %p\n", face, verts[i]);
fflush(err);
ret = false;
}
}
}
BLI_array_free(verts);
return ret;
}
#endif
/**
* Calculate the 2 loops which _would_ make up the newly rotated Edge
* but don't actually change anything.
*
* Use this to further inspect if the loops to be connected have issues:
*
* Examples:
* - the newly formed edge already exists
* - the new face would be degenerate (zero area / concave / bow-tie)
* - may want to measure if the new edge gives improved results topology.
* over the old one, as with beauty fill.
*
* \note #BM_edge_rotate_check must have already run.
*/
void BM_edge_calc_rotate(BMEdge *e, const bool ccw, BMLoop **r_l1, BMLoop **r_l2)
{
BMVert *v1, *v2;
BMFace *fa, *fb;
/* this should have already run */
BLI_assert(BM_edge_rotate_check(e) == true);
/* we know this will work */
BM_edge_face_pair(e, &fa, &fb);
/* so we can use `ccw` variable correctly,
* otherwise we could use the edges verts direct */
BM_edge_ordered_verts(e, &v1, &v2);
/* we could swap the verts _or_ the faces, swapping faces
* gives more predictable results since that way the next vert
* just stitches from face fa / fb */
if (!ccw) {
SWAP(BMFace *, fa, fb);
}
*r_l1 = BM_face_other_vert_loop(fb, v2, v1);
*r_l2 = BM_face_other_vert_loop(fa, v1, v2);
}
/**
* \brief Check if Rotate Edge is OK
*
* Quick check to see if we could rotate the edge,
* use this to avoid calling exceptions on common cases.
*/
bool BM_edge_rotate_check(BMEdge *e)
{
BMFace *fa, *fb;
if (BM_edge_face_pair(e, &fa, &fb)) {
BMLoop *la, *lb;
la = BM_face_other_vert_loop(fa, e->v2, e->v1);
lb = BM_face_other_vert_loop(fb, e->v2, e->v1);
/* check that the next vert in both faces isn't the same
* (ie - the next edge doesn't share the same faces).
* since we can't rotate usefully in this case. */
if (la->v == lb->v) {
return false;
}
/* mirror of the check above but in the opposite direction */
la = BM_face_other_vert_loop(fa, e->v1, e->v2);
lb = BM_face_other_vert_loop(fb, e->v1, e->v2);
if (la->v == lb->v) {
return false;
}
return true;
}
return false;
}
/**
* \brief Check if Edge Rotate Gives Degenerate Faces
*
* Check 2 cases
* 1) does the newly forms edge form a flipped face (compare with previous cross product)
* 2) does the newly formed edge cause a zero area corner (or close enough to be almost zero)
*
* \param e: The edge to test rotation.
* \param l1, l2: are the loops of the proposed verts to rotate too and should
* be the result of calling #BM_edge_calc_rotate
*/
bool BM_edge_rotate_check_degenerate(BMEdge *e, BMLoop *l1, BMLoop *l2)
{
/* note: for these vars 'old' just means initial edge state. */
float ed_dir_old[3]; /* edge vector */
float ed_dir_new[3]; /* edge vector */
float ed_dir_new_flip[3]; /* edge vector */
float ed_dir_v1_old[3];
float ed_dir_v2_old[3];
float ed_dir_v1_new[3];
float ed_dir_v2_new[3];
float cross_old[3];
float cross_new[3];
/* original verts - these will be in the edge 'e' */
BMVert *v1_old, *v2_old;
/* verts from the loops passed */
BMVert *v1, *v2;
/* These are the opposite verts - the verts that _would_ be used if `ccw` was inverted. */
BMVert *v1_alt, *v2_alt;
/* this should have already run */
BLI_assert(BM_edge_rotate_check(e) == true);
BM_edge_ordered_verts(e, &v1_old, &v2_old);
v1 = l1->v;
v2 = l2->v;
/* get the next vert along */
v1_alt = BM_face_other_vert_loop(l1->f, v1_old, v1)->v;
v2_alt = BM_face_other_vert_loop(l2->f, v2_old, v2)->v;
/* normalize all so comparisons are scale independent */
BLI_assert(BM_edge_exists(v1_old, v1));
BLI_assert(BM_edge_exists(v1, v1_alt));
BLI_assert(BM_edge_exists(v2_old, v2));
BLI_assert(BM_edge_exists(v2, v2_alt));
/* old and new edge vecs */
sub_v3_v3v3(ed_dir_old, v1_old->co, v2_old->co);
sub_v3_v3v3(ed_dir_new, v1->co, v2->co);
normalize_v3(ed_dir_old);
normalize_v3(ed_dir_new);
/* old edge corner vecs */
sub_v3_v3v3(ed_dir_v1_old, v1_old->co, v1->co);
sub_v3_v3v3(ed_dir_v2_old, v2_old->co, v2->co);
normalize_v3(ed_dir_v1_old);
normalize_v3(ed_dir_v2_old);
/* old edge corner vecs */
sub_v3_v3v3(ed_dir_v1_new, v1->co, v1_alt->co);
sub_v3_v3v3(ed_dir_v2_new, v2->co, v2_alt->co);
normalize_v3(ed_dir_v1_new);
normalize_v3(ed_dir_v2_new);
/* compare */
cross_v3_v3v3(cross_old, ed_dir_old, ed_dir_v1_old);
cross_v3_v3v3(cross_new, ed_dir_new, ed_dir_v1_new);
if (dot_v3v3(cross_old, cross_new) < 0.0f) { /* does this flip? */
return false;
}
cross_v3_v3v3(cross_old, ed_dir_old, ed_dir_v2_old);
cross_v3_v3v3(cross_new, ed_dir_new, ed_dir_v2_new);
if (dot_v3v3(cross_old, cross_new) < 0.0f) { /* does this flip? */
return false;
}
negate_v3_v3(ed_dir_new_flip, ed_dir_new);
/* result is zero area corner */
if ((dot_v3v3(ed_dir_new, ed_dir_v1_new) > 0.999f) ||
(dot_v3v3(ed_dir_new_flip, ed_dir_v2_new) > 0.999f)) {
return false;
}
return true;
}
bool BM_edge_rotate_check_beauty(BMEdge *e, BMLoop *l1, BMLoop *l2)
{
/* Stupid check for now:
* Could compare angles of surrounding edges
* before & after, but this is OK.*/
return (len_squared_v3v3(e->v1->co, e->v2->co) > len_squared_v3v3(l1->v->co, l2->v->co));
}
/**
* \brief Rotate Edge
*
* Spins an edge topologically,
* either counter-clockwise or clockwise depending on \a ccw.
*
* \return The spun edge, NULL on error
* (e.g., if the edge isn't surrounded by exactly two faces).
*
* \note This works by dissolving the edge then re-creating it,
* so the returned edge won't have the same pointer address as the original one.
*
* \see header definition for \a check_flag enum.
*/
BMEdge *BM_edge_rotate(BMesh *bm, BMEdge *e, const bool ccw, const short check_flag)
{
BMVert *v1, *v2;
BMLoop *l1, *l2;
BMFace *f;
BMEdge *e_new = NULL;
char f_active_prev = 0;
char f_hflag_prev_1;
char f_hflag_prev_2;
if (!BM_edge_rotate_check(e)) {
return NULL;
}
BM_edge_calc_rotate(e, ccw, &l1, &l2);
/* the loops will be freed so assign verts */
v1 = l1->v;
v2 = l2->v;
/* --------------------------------------- */
/* Checking Code - make sure we can rotate */
if (check_flag & BM_EDGEROT_CHECK_BEAUTY) {
if (!BM_edge_rotate_check_beauty(e, l1, l2)) {
return NULL;
}
}
/* check before applying */
if (check_flag & BM_EDGEROT_CHECK_EXISTS) {
if (BM_edge_exists(v1, v2)) {
return NULL;
}
}
/* slowest, check last */
if (check_flag & BM_EDGEROT_CHECK_DEGENERATE) {
if (!BM_edge_rotate_check_degenerate(e, l1, l2)) {
return NULL;
}
}
/* Done Checking */
/* ------------- */
/* --------------- */
/* Rotate The Edge */
/* first create the new edge, this is so we can copy the customdata from the old one
* if splice if disabled, always add in a new edge even if there's one there. */
e_new = BM_edge_create(
bm, v1, v2, e, (check_flag & BM_EDGEROT_CHECK_SPLICE) ? BM_CREATE_NO_DOUBLE : BM_CREATE_NOP);
f_hflag_prev_1 = l1->f->head.hflag;
f_hflag_prev_2 = l2->f->head.hflag;
/* maintain active face */
if (bm->act_face == l1->f) {
f_active_prev = 1;
}
else if (bm->act_face == l2->f) {
f_active_prev = 2;
}
const bool is_flipped = !BM_edge_is_contiguous(e);
/* don't delete the edge, manually remove the edge after so we can copy its attributes */
f = BM_faces_join_pair(
bm, BM_face_edge_share_loop(l1->f, e), BM_face_edge_share_loop(l2->f, e), true);
if (f == NULL) {
return NULL;
}
/* note, this assumes joining the faces _didnt_ also remove the verts.
* the #BM_edge_rotate_check will ensure this, but its possibly corrupt state or future edits
* break this */
if ((l1 = BM_face_vert_share_loop(f, v1)) && (l2 = BM_face_vert_share_loop(f, v2)) &&
BM_face_split(bm, f, l1, l2, NULL, NULL, true)) {
/* we should really be able to know the faces some other way,
* rather than fetching them back from the edge, but this is predictable
* where using the return values from face split isn't. - campbell */
BMFace *fa, *fb;
if (BM_edge_face_pair(e_new, &fa, &fb)) {
fa->head.hflag = f_hflag_prev_1;
fb->head.hflag = f_hflag_prev_2;
if (f_active_prev == 1) {
bm->act_face = fa;
}
else if (f_active_prev == 2) {
bm->act_face = fb;
}
if (is_flipped) {
BM_face_normal_flip(bm, fb);
if (ccw) {
/* Needed otherwise `ccw` toggles direction */
e_new->l = e_new->l->radial_next;
}
}
}
}
else {
return NULL;
}
return e_new;
}
/**
* \brief Rip a single face from a vertex fan
*/
BMVert *BM_face_loop_separate(BMesh *bm, BMLoop *l_sep)
{
return bmesh_kernel_unglue_region_make_vert(bm, l_sep);
}
BMVert *BM_face_loop_separate_multi_isolated(BMesh *bm, BMLoop *l_sep)
{
return bmesh_kernel_unglue_region_make_vert_multi_isolated(bm, l_sep);
}
BMVert *BM_face_loop_separate_multi(BMesh *bm, BMLoop **larr, int larr_len)
{
return bmesh_kernel_unglue_region_make_vert_multi(bm, larr, larr_len);
}
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