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/*
* ***** BEGIN GPL LICENSE BLOCK *****
*
* 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.
*
* Contributor(s): Joseph Eagar.
*
* ***** END GPL LICENSE BLOCK *****
*/
/** \file blender/bmesh/operators/bmo_beautify.c
* \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 "MEM_guardedalloc.h"
#include "bmesh.h"
#include "intern/bmesh_operators_private.h"
// #define DEBUG_TIME
#ifdef DEBUG_TIME
# include "PIL_time.h"
# include "PIL_time_utildefines.h"
#endif
enum {
VERT_RESTRICT_TAG = (1 << 0),
};
/* -------------------------------------------------------------------- */
/* GSet for edge rotation */
typedef struct EdRotState {
int v1, v2; /* edge vert, small -> large */
int f1, f2; /* face vert, small -> large */
} EdRotState;
static unsigned int erot_gsetutil_hash(const void *ptr)
{
const EdRotState *e_state = (const EdRotState *)ptr;
unsigned int
hash = BLI_ghashutil_inthash(SET_INT_IN_POINTER(e_state->v1));
hash ^= BLI_ghashutil_inthash(SET_INT_IN_POINTER(e_state->v2));
hash ^= BLI_ghashutil_inthash(SET_INT_IN_POINTER(e_state->f1));
hash ^= BLI_ghashutil_inthash(SET_INT_IN_POINTER(e_state->f2));
return hash;
}
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;
}
static GSet *erot_gset_new(void)
{
return BLI_gset_new(erot_gsetutil_hash, erot_gsetutil_cmp, __func__);
}
/* ensure v0 is smaller */
#define EDGE_ORD(v0, v1) \
if (v0 > v1) { \
v0 ^= v1; \
v1 ^= v0; \
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((BMEdge *)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 */
/**
* \return a negative value means the edge can be rotated.
*/
static float bm_edge_calc_rotate_beauty(const BMEdge *e, const int flag)
{
/* 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 *v1, *v2, *v3, *v4;
bool is_zero_a, is_zero_b;
float no[3];
float axis_mat[3][3];
v1 = e->l->prev->v->co; /* first face co */
v2 = e->l->v->co; /* e->v1 or e->v2*/
v3 = e->l->radial_next->prev->v->co; /* second face co */
v4 = e->l->next->v->co; /* e->v1 or e->v2*/
if (flag & VERT_RESTRICT_TAG) {
BMVert *v_a = e->l->prev->v, *v_b = e->l->radial_next->prev->v;
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;
}
// printf("%p %p %p %p - %p %p\n", v1, v2, v3, v4, e->l->f, e->l->radial_next->f);
BLI_assert((ELEM3(v1, v2, v3, v4) == false) &&
(ELEM3(v2, v1, v3, v4) == false) &&
(ELEM3(v3, v1, v2, v4) == false) &&
(ELEM3(v4, v1, v2, v3) == false));
is_zero_a = area_tri_v3(v2, v3, v4) <= FLT_EPSILON;
is_zero_b = area_tri_v3(v2, v4, v1) <= FLT_EPSILON;
if (LIKELY(is_zero_a == false && is_zero_b == false)) {
float no_a[3], no_b[3];
normal_tri_v3(no_a, v2, v3, v4); /* a */
normal_tri_v3(no_b, v2, v4, v1); /* b */
add_v3_v3v3(no, no_a, no_b);
if (UNLIKELY(normalize_v3(no) <= FLT_EPSILON)) {
break;
}
}
else if (is_zero_a == false) {
normal_tri_v3(no, v2, v3, v4); /* a */
}
else if (is_zero_b == false) {
normal_tri_v3(no, v2, v4, v1); /* b */
}
else {
/* both zero area, no useful normal can be calculated */
break;
}
// { float a = angle_normalized_v3v3(no_a, no_b); printf("~ %.7f\n", a); fflush(stdout);}
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);
}
// printf("%p %p %p %p - %p %p\n", v1, v2, v3, v4, e->l->f, e->l->radial_next->f);
if (is_quad_convex_v2(v1_xy, v2_xy, v3_xy, v4_xy)) {
/* testing rule: the area divided by the perimeter,
* check if (1-3) beats the existing (2-4) edge rotation */
float area_a, area_b;
float prim_a, prim_b;
float fac_24, fac_13;
float len_12, len_23, len_34, len_41, len_24, len_13;
/* edges around the quad */
len_12 = len_v2v2(v1_xy, v2_xy);
len_23 = len_v2v2(v2_xy, v3_xy);
len_34 = len_v2v2(v3_xy, v4_xy);
len_41 = len_v2v2(v4_xy, v1_xy);
/* edges crossing the quad interior */
len_13 = len_v2v2(v1_xy, v3_xy);
len_24 = len_v2v2(v2_xy, v4_xy);
/* edge (2-4), current state */
area_a = area_tri_v2(v2_xy, v3_xy, v4_xy);
area_b = area_tri_v2(v2_xy, v4_xy, v1_xy);
prim_a = len_23 + len_34 + len_24;
prim_b = len_24 + len_41 + len_12;
fac_24 = (area_a / prim_a) + (area_b / prim_b);
/* edge (1-3), new state */
area_a = area_tri_v2(v1_xy, v2_xy, v3_xy);
area_b = area_tri_v2(v1_xy, v3_xy, v4_xy);
prim_a = len_12 + len_23 + len_13;
prim_b = len_34 + len_41 + len_13;
fac_13 = (area_a / prim_a) + (area_b / prim_b);
/* negative number if (1-3) is an improved state */
return fac_24 - fac_13;
}
} while (false);
return FLT_MAX;
}
/* -------------------------------------------------------------------- */
/* Update the edge cost of rotation in the heap */
/* 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,
const int flag)
{
if (BM_elem_flag_test(e, BM_ELEM_TAG)) {
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);
//BLI_assert(BMO_elem_flag_test(bm, e->l->f, FACE_MARK) &&
// BMO_elem_flag_test(bm, e->l->radial_next->f, FACE_MARK));
/* 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);
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 int flag)
{
BMLoop *l;
BLI_assert(e->l->f->len == 3 &&
e->l->radial_next->f->len == 3);
l = e->l;
bm_edge_update_beauty_cost_single(l->next->e, eheap, eheap_table, edge_state_arr, flag);
bm_edge_update_beauty_cost_single(l->prev->e, eheap, eheap_table, edge_state_arr, flag);
l = l->radial_next;
bm_edge_update_beauty_cost_single(l->next->e, eheap, eheap_table, edge_state_arr, flag);
bm_edge_update_beauty_cost_single(l->prev->e, eheap, eheap_table, edge_state_arr, flag);
}
/* -------------------------------------------------------------------- */
/* Beautify Fill */
#define ELE_NEW 1
#define FACE_MARK 2
/**
* \note All edges in \a edge_array must be tagged and
* have their index values set according to their position in the array.
*/
static void bm_mesh_beautify_fill(BMesh *bm, BMEdge **edge_array, const int edge_array_len,
const int flag)
{
Heap *eheap; /* edge heap */
HeapNode **eheap_table; /* edge index aligned table pointing to the eheap */
GSet **edge_state_arr = MEM_callocN(edge_array_len * sizeof(GSet *), __func__);
BLI_mempool *edge_state_pool = BLI_mempool_create(sizeof(EdRotState), 512, 512, BLI_MEMPOOL_SYSMALLOC);
int i;
#ifdef DEBUG_TIME
TIMEIT_START(beautify_fill);
#endif
eheap = BLI_heap_new_ex(edge_array_len);
eheap_table = MEM_mallocN(sizeof(HeapNode *) * 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);
if (cost < 0.0f) {
eheap_table[i] = BLI_heap_insert(eheap, cost, e);
}
else {
eheap_table[i] = NULL;
}
}
while (BLI_heap_is_empty(eheap) == false) {
BMEdge *e = BLI_heap_popmin(eheap);
i = BM_elem_index_get(e);
eheap_table[i] = NULL;
e = BM_edge_rotate(bm, e, false, BM_EDGEROT_CHECK_EXISTS);
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, flag);
/* update flags */
BMO_elem_flag_enable(bm, e, ELE_NEW);
BMO_elem_flag_enable(bm, e->l->f, FACE_MARK | ELE_NEW);
BMO_elem_flag_enable(bm, e->l->radial_next->f, FACE_MARK | ELE_NEW);
}
}
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
}
void bmo_beautify_fill_exec(BMesh *bm, BMOperator *op)
{
BMIter iter;
BMOIter siter;
BMFace *f;
BMEdge *e;
const bool use_restrict_tag = BMO_slot_bool_get(op->slots_in, "use_restrict_tag");
const int flag = (use_restrict_tag ? VERT_RESTRICT_TAG : 0);
BMEdge **edge_array;
int edge_array_len = 0;
BMO_ITER (f, &siter, op->slots_in, "faces", BM_FACE) {
if (f->len == 3) {
BMO_elem_flag_enable(bm, f, FACE_MARK);
}
}
BM_ITER_MESH (e, &iter, bm, BM_EDGES_OF_MESH) {
BM_elem_flag_disable(e, BM_ELEM_TAG);
}
/* will over alloc if some edges can't be rotated */
edge_array = MEM_mallocN(sizeof(*edge_array) * BMO_slot_buffer_count(op->slots_in, "edges"), __func__);
BMO_ITER (e, &siter, op->slots_in, "edges", BM_EDGE) {
/* edge is manifold and can be rotated */
if (BM_edge_rotate_check(e) &&
/* faces are tagged */
BMO_elem_flag_test(bm, e->l->f, FACE_MARK) &&
BMO_elem_flag_test(bm, e->l->radial_next->f, FACE_MARK))
{
BM_elem_index_set(e, edge_array_len); /* set_dirty */
BM_elem_flag_enable(e, BM_ELEM_TAG);
edge_array[edge_array_len] = e;
edge_array_len++;
}
}
bm->elem_index_dirty |= BM_EDGE;
bm_mesh_beautify_fill(bm, edge_array, edge_array_len, flag);
MEM_freeN(edge_array);
BMO_slot_buffer_from_enabled_flag(bm, op, op->slots_out, "geom.out", BM_EDGE | BM_FACE, ELE_NEW);
}
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