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blender-archive/source/blender/bmesh/tools/bmesh_beautify.c

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C

/*
* 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
*
* Beautify the mesh by rotating edges between triangles
* to more attractive positions until no more rotations can be made.
*
* In principle this is very simple however there is the possibility of
* going into an eternal loop where edges keep rotating.
* To avoid this - each edge stores a set of it previous
* states so as not to rotate back.
*
* TODO
* - Take face normals into account.
*/
#include "BLI_math.h"
#include "BLI_heap.h"
#include "BLI_polyfill_2d_beautify.h"
#include "MEM_guardedalloc.h"
#include "bmesh.h"
#include "bmesh_beautify.h" /* own include */
// #define DEBUG_TIME
#ifdef DEBUG_TIME
# include "PIL_time.h"
# include "PIL_time_utildefines.h"
#endif
/* -------------------------------------------------------------------- */
/* GSet for edge rotation */
typedef struct EdRotState {
int v1, v2; /* edge vert, small -> large */
int f1, f2; /* face vert, small -> large */
} EdRotState;
#if 0
/* use BLI_ghashutil_inthash_v4 direct */
static uint erot_gsetutil_hash(const void *ptr)
{
const EdRotState *e_state = (const EdRotState *)ptr;
return BLI_ghashutil_inthash_v4(&e_state->v1);
}
#endif
#if 0
static int erot_gsetutil_cmp(const void *a, const void *b)
{
const EdRotState *e_state_a = (const EdRotState *)a;
const EdRotState *e_state_b = (const EdRotState *)b;
if (e_state_a->v1 < e_state_b->v1) {
return -1;
}
else if (e_state_a->v1 > e_state_b->v1) {
return 1;
}
else if (e_state_a->v2 < e_state_b->v2) {
return -1;
}
else if (e_state_a->v2 > e_state_b->v2) {
return 1;
}
else if (e_state_a->f1 < e_state_b->f1) {
return -1;
}
else if (e_state_a->f1 > e_state_b->f1) {
return 1;
}
else if (e_state_a->f2 < e_state_b->f2) {
return -1;
}
else if (e_state_a->f2 > e_state_b->f2) {
return 1;
}
else {
return 0;
}
}
#endif
static GSet *erot_gset_new(void)
{
return BLI_gset_new(BLI_ghashutil_inthash_v4_p, BLI_ghashutil_inthash_v4_cmp, __func__);
}
/* ensure v0 is smaller */
#define EDGE_ORD(v0, v1) \
if (v0 > v1) { \
SWAP(int, v0, v1); \
} \
(void)0
static void erot_state_ex(const BMEdge *e, int v_index[2], int f_index[2])
{
BLI_assert(BM_edge_is_manifold(e));
BLI_assert(BM_vert_in_edge(e, e->l->prev->v) == false);
BLI_assert(BM_vert_in_edge(e, e->l->radial_next->prev->v) == false);
/* verts of the edge */
v_index[0] = BM_elem_index_get(e->v1);
v_index[1] = BM_elem_index_get(e->v2);
EDGE_ORD(v_index[0], v_index[1]);
/* verts of each of the 2 faces attached to this edge
* (that are not apart of this edge) */
f_index[0] = BM_elem_index_get(e->l->prev->v);
f_index[1] = BM_elem_index_get(e->l->radial_next->prev->v);
EDGE_ORD(f_index[0], f_index[1]);
}
static void erot_state_current(const BMEdge *e, EdRotState *e_state)
{
erot_state_ex(e, &e_state->v1, &e_state->f1);
}
static void erot_state_alternate(const BMEdge *e, EdRotState *e_state)
{
erot_state_ex(e, &e_state->f1, &e_state->v1);
}
/* -------------------------------------------------------------------- */
/* Calculate the improvement of rotating the edge */
static float bm_edge_calc_rotate_beauty__area(const float v1[3],
const float v2[3],
const float v3[3],
const float v4[3])
{
/* not a loop (only to be able to break out) */
do {
float v1_xy[2], v2_xy[2], v3_xy[2], v4_xy[2];
/* first get the 2d values */
{
const float eps = 1e-5;
float no_a[3], no_b[3];
float no[3];
float axis_mat[3][3];
float no_scale;
cross_tri_v3(no_a, v2, v3, v4);
cross_tri_v3(no_b, v2, v4, v1);
// printf("%p %p %p %p - %p %p\n", v1, v2, v3, v4, e->l->f, e->l->radial_next->f);
BLI_assert((ELEM(v1, v2, v3, v4) == false) && (ELEM(v2, v1, v3, v4) == false) &&
(ELEM(v3, v1, v2, v4) == false) && (ELEM(v4, v1, v2, v3) == false));
add_v3_v3v3(no, no_a, no_b);
if (UNLIKELY((no_scale = normalize_v3(no)) == 0.0f)) {
break;
}
axis_dominant_v3_to_m3(axis_mat, no);
mul_v2_m3v3(v1_xy, axis_mat, v1);
mul_v2_m3v3(v2_xy, axis_mat, v2);
mul_v2_m3v3(v3_xy, axis_mat, v3);
mul_v2_m3v3(v4_xy, axis_mat, v4);
/**
* Check if input faces are already flipped.
* Logic for 'signum_i' addition is:
*
* Accept:
* - (1, 1) or (-1, -1): same side (common case).
* - (-1/1, 0): one degenerate, OK since we may rotate into a valid state.
*
* Ignore:
* - (-1, 1): opposite winding, ignore.
* - ( 0, 0): both degenerate, ignore.
*
* \note The cross product is divided by 'no_scale'
* so the rotation calculation is scale independent.
*/
if (!(signum_i_ex(cross_tri_v2(v2_xy, v3_xy, v4_xy) / no_scale, eps) +
signum_i_ex(cross_tri_v2(v2_xy, v4_xy, v1_xy) / no_scale, eps))) {
break;
}
}
/**
* Important to lock degenerate here,
* since the triangle pars will be projected into different 2D spaces.
* Allowing to rotate out of a degenerate state can flip the faces
* (when performed iteratively).
*/
return BLI_polyfill_beautify_quad_rotate_calc_ex(v1_xy, v2_xy, v3_xy, v4_xy, true);
} while (false);
return FLT_MAX;
}
static float bm_edge_calc_rotate_beauty__angle(const float v1[3],
const float v2[3],
const float v3[3],
const float v4[3])
{
/* not a loop (only to be able to break out) */
do {
float no_a[3], no_b[3];
float angle_24, angle_13;
/* edge (2-4), current state */
normal_tri_v3(no_a, v2, v3, v4);
normal_tri_v3(no_b, v2, v4, v1);
angle_24 = angle_normalized_v3v3(no_a, no_b);
/* edge (1-3), new state */
/* only check new state for degenerate outcome */
if ((normal_tri_v3(no_a, v1, v2, v3) == 0.0f) || (normal_tri_v3(no_b, v1, v3, v4) == 0.0f)) {
break;
}
angle_13 = angle_normalized_v3v3(no_a, no_b);
return angle_13 - angle_24;
} while (false);
return FLT_MAX;
}
/**
* Assuming we have 2 triangles sharing an edge (2 - 4),
* check if the edge running from (1 - 3) gives better results.
*
* \return (negative number means the edge can be rotated, lager == better).
*/
float BM_verts_calc_rotate_beauty(const BMVert *v1,
const BMVert *v2,
const BMVert *v3,
const BMVert *v4,
const short flag,
const short method)
{
/* not a loop (only to be able to break out) */
do {
if (flag & VERT_RESTRICT_TAG) {
const BMVert *v_a = v1, *v_b = v3;
if (BM_elem_flag_test(v_a, BM_ELEM_TAG) == BM_elem_flag_test(v_b, BM_ELEM_TAG)) {
break;
}
}
if (UNLIKELY(v1 == v3)) {
// printf("This should never happen, but does sometimes!\n");
break;
}
switch (method) {
case 0:
return bm_edge_calc_rotate_beauty__area(v1->co, v2->co, v3->co, v4->co);
default:
return bm_edge_calc_rotate_beauty__angle(v1->co, v2->co, v3->co, v4->co);
}
} while (false);
return FLT_MAX;
}
static float bm_edge_calc_rotate_beauty(const BMEdge *e, const short flag, const short method)
{
const BMVert *v1, *v2, *v3, *v4;
v1 = e->l->prev->v; /* first vert co */
v2 = e->l->v; /* e->v1 or e->v2*/
v3 = e->l->radial_next->prev->v; /* second vert co */
v4 = e->l->next->v; /* e->v1 or e->v2*/
return BM_verts_calc_rotate_beauty(v1, v2, v3, v4, flag, method);
}
/* -------------------------------------------------------------------- */
/* Update the edge cost of rotation in the heap */
BLI_INLINE bool edge_in_array(const BMEdge *e, const BMEdge **edge_array, const int edge_array_len)
{
const int index = BM_elem_index_get(e);
return ((index >= 0) && (index < edge_array_len) && (e == edge_array[index]));
}
/* recalc an edge in the heap (surrounding geometry has changed) */
static void bm_edge_update_beauty_cost_single(BMEdge *e,
Heap *eheap,
HeapNode **eheap_table,
GSet **edge_state_arr,
/* only for testing the edge is in the array */
const BMEdge **edge_array,
const int edge_array_len,
const short flag,
const short method)
{
if (edge_in_array(e, edge_array, edge_array_len)) {
const int i = BM_elem_index_get(e);
GSet *e_state_set = edge_state_arr[i];
if (eheap_table[i]) {
BLI_heap_remove(eheap, eheap_table[i]);
eheap_table[i] = NULL;
}
/* check if we can add it back */
BLI_assert(BM_edge_is_manifold(e) == true);
/* check we're not moving back into a state we have been in before */
if (e_state_set != NULL) {
EdRotState e_state_alt;
erot_state_alternate(e, &e_state_alt);
if (BLI_gset_haskey(e_state_set, (void *)&e_state_alt)) {
// printf(" skipping, we already have this state\n");
return;
}
}
{
/* recalculate edge */
const float cost = bm_edge_calc_rotate_beauty(e, flag, method);
if (cost < 0.0f) {
eheap_table[i] = BLI_heap_insert(eheap, cost, e);
}
else {
eheap_table[i] = NULL;
}
}
}
}
/* we have rotated an edge, tag other edges and clear this one */
static void bm_edge_update_beauty_cost(BMEdge *e,
Heap *eheap,
HeapNode **eheap_table,
GSet **edge_state_arr,
const BMEdge **edge_array,
const int edge_array_len,
/* only for testing the edge is in the array */
const short flag,
const short method)
{
int i;
BMEdge *e_arr[4] = {
e->l->next->e,
e->l->prev->e,
e->l->radial_next->next->e,
e->l->radial_next->prev->e,
};
BLI_assert(e->l->f->len == 3 && e->l->radial_next->f->len == 3);
BLI_assert(BM_edge_face_count_is_equal(e, 2));
for (i = 0; i < 4; i++) {
bm_edge_update_beauty_cost_single(
e_arr[i], eheap, eheap_table, edge_state_arr, edge_array, edge_array_len, flag, method);
}
}
/* -------------------------------------------------------------------- */
/* Beautify Fill */
/**
* \note This function sets the edge indices to invalid values.
*/
void BM_mesh_beautify_fill(BMesh *bm,
BMEdge **edge_array,
const int edge_array_len,
const short flag,
const short method,
const short oflag_edge,
const short oflag_face)
{
Heap *eheap; /* edge heap */
HeapNode **eheap_table; /* edge index aligned table pointing to the eheap */
GSet **edge_state_arr = MEM_callocN((size_t)edge_array_len * sizeof(GSet *), __func__);
BLI_mempool *edge_state_pool = BLI_mempool_create(sizeof(EdRotState), 0, 512, BLI_MEMPOOL_NOP);
int i;
#ifdef DEBUG_TIME
TIMEIT_START(beautify_fill);
#endif
eheap = BLI_heap_new_ex((uint)edge_array_len);
eheap_table = MEM_mallocN(sizeof(HeapNode *) * (size_t)edge_array_len, __func__);
/* build heap */
for (i = 0; i < edge_array_len; i++) {
BMEdge *e = edge_array[i];
const float cost = bm_edge_calc_rotate_beauty(e, flag, method);
if (cost < 0.0f) {
eheap_table[i] = BLI_heap_insert(eheap, cost, e);
}
else {
eheap_table[i] = NULL;
}
BM_elem_index_set(e, i); /* set_dirty */
}
bm->elem_index_dirty |= BM_EDGE;
while (BLI_heap_is_empty(eheap) == false) {
BMEdge *e = BLI_heap_pop_min(eheap);
i = BM_elem_index_get(e);
eheap_table[i] = NULL;
BLI_assert(BM_edge_face_count_is_equal(e, 2));
e = BM_edge_rotate(bm, e, false, BM_EDGEROT_CHECK_EXISTS);
BLI_assert(e == NULL || BM_edge_face_count_is_equal(e, 2));
if (LIKELY(e)) {
GSet *e_state_set = edge_state_arr[i];
/* add the new state into the set so we don't move into this state again
* note: we could add the previous state too but this isn't essential)
* for avoiding eternal loops */
EdRotState *e_state = BLI_mempool_alloc(edge_state_pool);
erot_state_current(e, e_state);
if (UNLIKELY(e_state_set == NULL)) {
edge_state_arr[i] = e_state_set = erot_gset_new(); /* store previous state */
}
BLI_assert(BLI_gset_haskey(e_state_set, (void *)e_state) == false);
BLI_gset_insert(e_state_set, e_state);
// printf(" %d -> %d, %d\n", i, BM_elem_index_get(e->v1), BM_elem_index_get(e->v2));
/* maintain the index array */
edge_array[i] = e;
BM_elem_index_set(e, i);
/* recalculate faces connected on the heap */
bm_edge_update_beauty_cost(e,
eheap,
eheap_table,
edge_state_arr,
(const BMEdge **)edge_array,
edge_array_len,
flag,
method);
/* update flags */
if (oflag_edge) {
BMO_edge_flag_enable(bm, e, oflag_edge);
}
if (oflag_face) {
BMO_face_flag_enable(bm, e->l->f, oflag_face);
BMO_face_flag_enable(bm, e->l->radial_next->f, oflag_face);
}
}
}
BLI_heap_free(eheap, NULL);
MEM_freeN(eheap_table);
for (i = 0; i < edge_array_len; i++) {
if (edge_state_arr[i]) {
BLI_gset_free(edge_state_arr[i], NULL);
}
}
MEM_freeN(edge_state_arr);
BLI_mempool_destroy(edge_state_pool);
#ifdef DEBUG_TIME
TIMEIT_END(beautify_fill);
#endif
}