1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
|
/*
* 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
*
* normal recalculation.
*/
#include "MEM_guardedalloc.h"
#include "BLI_math.h"
#include "BLI_linklist_stack.h"
#include "bmesh.h"
#include "intern/bmesh_operators_private.h" /* own include */
/********* righthand faces implementation ****** */
#define FACE_FLAG (1 << 0)
#define FACE_FLIP (1 << 1)
#define FACE_TEMP (1 << 2)
static bool bmo_recalc_normal_loop_filter_cb(const BMLoop *l, void *UNUSED(user_data))
{
return BM_edge_is_manifold(l->e);
}
/**
* This uses a more comprehensive test to see if the furthest face from the center
* is pointing towards the center or not.
*
* A simple test could just check the dot product of the faces-normal and the direction from the center,
* however this can fail for faces which make a sharp spike. eg:
*
* <pre>
* +
* |\ <- face
* + +
* \ \
* \ \
* \ +--------------+
* \ |
* \ center -> + |
* \ |
* +------------+
* </pre>
*
* In the example above, the a\ face can point towards the \a center
* which would end up flipping the normals inwards.
*
* To take these spikes into account, find the furthest face-loop-vertex.
*/
/**
* \return a face index in \a faces and set \a r_is_flip if the face is flipped away from the center.
*/
static int recalc_face_normals_find_index(BMesh *bm,
BMFace **faces,
const int faces_len,
bool *r_is_flip)
{
const float eps = FLT_EPSILON;
float cent_area_accum = 0.0f;
float cent[3];
const float cent_fac = 1.0f / (float)faces_len;
bool is_flip = false;
int f_start_index;
int i;
/* Search for the best loop. Members are compared in-order defined here. */
struct {
/* Squared distance from the center to the loops vertex 'l->v'.
* The normalized direction between the center and this vertex is also used for the dot-products below. */
float dist_sq;
/* Signed dot product using the normalized edge vector,
* (best of 'l->prev->v' or 'l->next->v'). */
float edge_dot;
/* Unsigned dot product using the loop-normal
* (sign is used to check if we need to flip) */
float loop_dot;
} best, test;
UNUSED_VARS_NDEBUG(bm);
zero_v3(cent);
/* first calculate the center */
for (i = 0; i < faces_len; i++) {
float f_cent[3];
const float f_area = BM_face_calc_area(faces[i]);
BM_face_calc_center_median_weighted(faces[i], f_cent);
madd_v3_v3fl(cent, f_cent, cent_fac * f_area);
cent_area_accum += f_area;
BLI_assert(BMO_face_flag_test(bm, faces[i], FACE_TEMP) == 0);
BLI_assert(BM_face_is_normal_valid(faces[i]));
}
if (cent_area_accum != 0.0f) {
mul_v3_fl(cent, 1.0f / cent_area_accum);
}
/* Distances must start above zero,
* or we can't do meaningful calculations based on the direction to the center */
best.dist_sq = eps;
best.edge_dot = best.loop_dot = -FLT_MAX;
/* used in degenerate cases only */
f_start_index = 0;
/**
* Find the outer-most vertex, comparing distance to the center,
* then the outer-most loop attached to that vertex.
*
* Important this is correctly detected,
* where casting a ray from the center wont hit any loops past this one.
* Otherwise the result may be incorrect.
*/
for (i = 0; i < faces_len; i++) {
BMLoop *l_iter, *l_first;
l_iter = l_first = BM_FACE_FIRST_LOOP(faces[i]);
do {
bool is_best_dist_sq;
float dir[3];
sub_v3_v3v3(dir, l_iter->v->co, cent);
test.dist_sq = len_squared_v3(dir);
is_best_dist_sq = (test.dist_sq > best.dist_sq);
if (is_best_dist_sq || (test.dist_sq == best.dist_sq)) {
float edge_dir_pair[2][3];
mul_v3_fl(dir, 1.0f / sqrtf(test.dist_sq));
sub_v3_v3v3(edge_dir_pair[0], l_iter->next->v->co, l_iter->v->co);
sub_v3_v3v3(edge_dir_pair[1], l_iter->prev->v->co, l_iter->v->co);
if ((normalize_v3(edge_dir_pair[0]) > eps) && (normalize_v3(edge_dir_pair[1]) > eps)) {
bool is_best_edge_dot;
test.edge_dot = max_ff(dot_v3v3(dir, edge_dir_pair[0]), dot_v3v3(dir, edge_dir_pair[1]));
is_best_edge_dot = (test.edge_dot > best.edge_dot);
if (is_best_dist_sq || is_best_edge_dot || (test.edge_dot == best.edge_dot)) {
float loop_dir[3];
cross_v3_v3v3(loop_dir, edge_dir_pair[0], edge_dir_pair[1]);
if (normalize_v3(loop_dir) > eps) {
float loop_dir_dot;
/* Highly unlikely the furthest loop is also the concave part of an ngon,
* but it can be contrived with _very_ non-planar faces - so better check. */
if (UNLIKELY(dot_v3v3(loop_dir, l_iter->f->no) < 0.0f)) {
negate_v3(loop_dir);
}
loop_dir_dot = dot_v3v3(dir, loop_dir);
test.loop_dot = fabsf(loop_dir_dot);
if (is_best_dist_sq || is_best_edge_dot || (test.loop_dot > best.loop_dot)) {
best = test;
f_start_index = i;
is_flip = (loop_dir_dot < 0.0f);
}
}
}
}
}
} while ((l_iter = l_iter->next) != l_first);
}
*r_is_flip = is_flip;
return f_start_index;
}
/**
* Given an array of faces, recalculate their normals.
* this functions assumes all faces in the array are connected by edges.
*
* \param bm:
* \param faces: Array of connected faces.
* \param faces_len: Length of \a faces
* \param oflag: Flag to check before doing the actual face flipping.
*/
static void bmo_recalc_face_normals_array(BMesh *bm,
BMFace **faces,
const int faces_len,
const short oflag)
{
int i, f_start_index;
const short oflag_flip = oflag | FACE_FLIP;
bool is_flip;
BMFace *f;
BLI_LINKSTACK_DECLARE(fstack, BMFace *);
f_start_index = recalc_face_normals_find_index(bm, faces, faces_len, &is_flip);
if (is_flip) {
BMO_face_flag_enable(bm, faces[f_start_index], FACE_FLIP);
}
/* now that we've found our starting face, make all connected faces
* have the same winding. this is done recursively, using a manual
* stack (if we use simple function recursion, we'd end up overloading
* the stack on large meshes). */
BLI_LINKSTACK_INIT(fstack);
BLI_LINKSTACK_PUSH(fstack, faces[f_start_index]);
BMO_face_flag_enable(bm, faces[f_start_index], FACE_TEMP);
while ((f = BLI_LINKSTACK_POP(fstack))) {
const bool flip_state = BMO_face_flag_test_bool(bm, f, FACE_FLIP);
BMLoop *l_iter, *l_first;
l_iter = l_first = BM_FACE_FIRST_LOOP(f);
do {
BMLoop *l_other = l_iter->radial_next;
if ((l_other != l_iter) && bmo_recalc_normal_loop_filter_cb(l_iter, NULL)) {
if (!BMO_face_flag_test(bm, l_other->f, FACE_TEMP)) {
BMO_face_flag_enable(bm, l_other->f, FACE_TEMP);
BMO_face_flag_set(bm, l_other->f, FACE_FLIP, (l_other->v == l_iter->v) != flip_state);
BLI_LINKSTACK_PUSH(fstack, l_other->f);
}
}
} while ((l_iter = l_iter->next) != l_first);
}
BLI_LINKSTACK_FREE(fstack);
/* apply flipping to oflag'd faces */
for (i = 0; i < faces_len; i++) {
if (BMO_face_flag_test(bm, faces[i], oflag_flip) == oflag_flip) {
BM_face_normal_flip(bm, faces[i]);
}
BMO_face_flag_disable(bm, faces[i], FACE_TEMP);
}
}
/*
* put normal to the outside, and set the first direction flags in edges
*
* then check the object, and set directions / direction-flags: but only for edges with 1 or 2 faces
* this is in fact the 'select connected'
*
* in case all faces were not done: start over with 'find the ultimate ...' */
void bmo_recalc_face_normals_exec(BMesh *bm, BMOperator *op)
{
int *groups_array = MEM_mallocN(sizeof(*groups_array) * bm->totface, __func__);
BMFace **faces_grp = MEM_mallocN(sizeof(*faces_grp) * bm->totface, __func__);
int(*group_index)[2];
const int group_tot = BM_mesh_calc_face_groups(
bm, groups_array, &group_index, bmo_recalc_normal_loop_filter_cb, NULL, 0, BM_EDGE);
int i;
BMO_slot_buffer_flag_enable(bm, op->slots_in, "faces", BM_FACE, FACE_FLAG);
BM_mesh_elem_table_ensure(bm, BM_FACE);
for (i = 0; i < group_tot; i++) {
const int fg_sta = group_index[i][0];
const int fg_len = group_index[i][1];
int j;
bool is_calc = false;
for (j = 0; j < fg_len; j++) {
faces_grp[j] = BM_face_at_index(bm, groups_array[fg_sta + j]);
if (is_calc == false) {
is_calc = BMO_face_flag_test_bool(bm, faces_grp[j], FACE_FLAG);
}
}
if (is_calc) {
bmo_recalc_face_normals_array(bm, faces_grp, fg_len, FACE_FLAG);
}
}
MEM_freeN(faces_grp);
MEM_freeN(groups_array);
MEM_freeN(group_index);
}
|