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Fix T41523: Mesh triangle fill creates flipped faces

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Calculate projection normal using edge-pairs
This commit is contained in:
Campbell Barton
2014-08-21 15:07:07 +10:00
parent 1706182be4
commit afa6d4e21f
1 changed files with 82 additions and 6 deletions
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88
source/blender/bmesh/operators/bmo_triangulate.c
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@@ -26,10 +26,12 @@
* Triangulate faces, also defines triangle fill.
*/
#include "MEM_guardedalloc.h"
#include "DNA_listBase.h"
#include "BLI_math.h"
#include "BLI_smallhash.h"
#include "BLI_sort_utils.h"
#include "BLI_scanfill.h"
#include "bmesh.h"
@@ -56,6 +58,10 @@ void bmo_triangulate_exec(BMesh *bm, BMOperator *op)
BMO_slot_buffer_from_enabled_hflag(bm, op, op->slots_out, "faces.out", BM_FACE, BM_ELEM_TAG);
}
struct SortNormal {
float value; /* keep first */
float no[3];
};
void bmo_triangle_fill_exec(BMesh *bm, BMOperator *op)
{
@@ -67,7 +73,7 @@ void bmo_triangle_fill_exec(BMesh *bm, BMOperator *op)
/* ScanFillEdge *sf_edge; */ /* UNUSED */
ScanFillFace *sf_tri;
GHash *sf_vert_map;
float normal[3], *normal_pt;
float normal[3];
const int scanfill_flag = BLI_SCANFILL_CALC_HOLES | BLI_SCANFILL_CALC_POLYS | BLI_SCANFILL_CALC_LOOSE;
bool calc_winding = false;
@@ -99,16 +105,86 @@ void bmo_triangle_fill_exec(BMesh *bm, BMOperator *op)
}
BLI_ghash_free(sf_vert_map, NULL, NULL);
if (is_zero_v3(normal)) {
normal_pt = NULL;
/* calculate the normal from the cross product of vert-edge pairs.
* Since we don't know winding, just accumulate */
ScanFillVert *sf_vert;
struct SortNormal *nors;
const unsigned int nors_tot = BLI_ghash_size(sf_vert_map);
unsigned int i;
bool is_degenerate = true;
nors = MEM_mallocN(sizeof(*nors) * nors_tot, __func__);
for (sf_vert = sf_ctx.fillvertbase.first, i = 0; sf_vert; sf_vert = sf_vert->next, i++) {
BMVert *v = sf_vert->tmp.p;
BMIter eiter;
BMEdge *e, *e_pair[2];
unsigned int e_index = 0;
nors[i].value = -1.0f;
/* only use if 'is_degenerate' stays true */
add_v3_v3(normal, v->no);
BM_ITER_ELEM (e, &eiter, v, BM_EDGES_OF_VERT) {
if (BMO_elem_flag_test(bm, e, EDGE_MARK)) {
if (e_index == 2) {
e_index = 0;
break;
}
e_pair[e_index++] = e;
}
}
if (e_index == 2) {
float dir_a[3], dir_b[3];
is_degenerate = false;
sub_v3_v3v3(dir_a, v->co, BM_edge_other_vert(e_pair[0], v)->co);
sub_v3_v3v3(dir_b, v->co, BM_edge_other_vert(e_pair[1], v)->co);
cross_v3_v3v3(nors[i].no, dir_a, dir_b);
nors[i].value = len_squared_v3(nors[i].no);
/* only to get deterministic behavior (for initial normal) */
if (len_squared_v3(dir_a) > len_squared_v3(dir_b)) {
negate_v3(nors[i].no);
}
}
}
if (UNLIKELY(is_degenerate)) {
/* no vertices have 2 edges?
* in this case fall back to the average vertex normals */
}
else {
qsort(nors, nors_tot, sizeof(*nors), BLI_sortutil_cmp_float_reverse);
copy_v3_v3(normal, nors[0].no);
for (i = 0; i < nors_tot; i++) {
if (UNLIKELY(nors[i].value == -1.0f)) {
break;
}
if (dot_v3v3(normal, nors[i].no) < 0.0f) {
negate_v3(nors[i].no);
}
add_v3_v3(normal, nors[i].no);
}
normalize_v3(normal);
}
MEM_freeN(nors);
}
else {
normalize_v3(normal);
normal_pt = normal;
calc_winding = false;
}
BLI_scanfill_calc_ex(&sf_ctx, scanfill_flag, normal_pt);
normalize_v3(normal);
BLI_scanfill_calc_ex(&sf_ctx, scanfill_flag, normal);
/* if we have existing faces, base winding on those */