diff options
Diffstat (limited to 'source/blender/bmesh/intern/bmesh_mesh_tessellate.c')
-rw-r--r-- | source/blender/bmesh/intern/bmesh_mesh_tessellate.c | 277 |
1 files changed, 277 insertions, 0 deletions
diff --git a/source/blender/bmesh/intern/bmesh_mesh_tessellate.c b/source/blender/bmesh/intern/bmesh_mesh_tessellate.c new file mode 100644 index 00000000000..bde2c75a079 --- /dev/null +++ b/source/blender/bmesh/intern/bmesh_mesh_tessellate.c @@ -0,0 +1,277 @@ +/* + * 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 code for polygon tessellation + * (creating triangles from polygons). + */ + +#include "DNA_meshdata_types.h" + +#include "MEM_guardedalloc.h" + +#include "BLI_alloca.h" +#include "BLI_heap.h" +#include "BLI_linklist.h" +#include "BLI_math.h" +#include "BLI_memarena.h" +#include "BLI_polyfill_2d.h" +#include "BLI_polyfill_2d_beautify.h" + +#include "bmesh.h" +#include "bmesh_tools.h" + +/** + * \brief BM_mesh_calc_tessellation get the looptris and its number from a certain bmesh + * \param looptris: + * + * \note \a looptris Must be pre-allocated to at least the size of given by: poly_to_tri_count + */ +void BM_mesh_calc_tessellation(BMesh *bm, BMLoop *(*looptris)[3]) +{ + /* Avoid polygon filling logic for 3-4 sided faces. */ +#define USE_TESSFACE_SPEEDUP + +#ifndef NDEBUG + const int looptris_tot = poly_to_tri_count(bm->totface, bm->totloop); +#endif + + BMIter iter; + BMFace *efa; + int i = 0; + + MemArena *arena = NULL; + + BM_ITER_MESH (efa, &iter, bm, BM_FACES_OF_MESH) { + BLI_assert(efa->len >= 3); +#ifdef USE_TESSFACE_SPEEDUP + if (efa->len == 3) { + /* `0 1 2` -> `0 1 2` */ + BMLoop *l; + BMLoop **l_ptr = looptris[i++]; + l_ptr[0] = l = BM_FACE_FIRST_LOOP(efa); + l_ptr[1] = l = l->next; + l_ptr[2] = l->next; + } + else if (efa->len == 4) { + /* `0 1 2 3` -> (`0 1 2`, `0 2 3`) */ + BMLoop *l; + BMLoop **l_ptr_a = looptris[i++]; + BMLoop **l_ptr_b = looptris[i++]; + (l_ptr_a[0] = l_ptr_b[0] = l = BM_FACE_FIRST_LOOP(efa)); + (l_ptr_a[1] = l = l->next); + (l_ptr_a[2] = l_ptr_b[1] = l = l->next); + (l_ptr_b[2] = l->next); + + if (UNLIKELY(is_quad_flip_v3_first_third_fast( + l_ptr_a[0]->v->co, l_ptr_a[1]->v->co, l_ptr_a[2]->v->co, l_ptr_b[2]->v->co))) { + /* flip out of degenerate 0-2 state. */ + l_ptr_a[2] = l_ptr_b[2]; + l_ptr_b[0] = l_ptr_a[1]; + } + } + else +#endif /* USE_TESSFACE_SPEEDUP */ + { + int j; + + BMLoop *l_iter; + BMLoop *l_first; + BMLoop **l_arr; + + float axis_mat[3][3]; + float(*projverts)[2]; + uint(*tris)[3]; + + const int totfilltri = efa->len - 2; + + if (UNLIKELY(arena == NULL)) { + arena = BLI_memarena_new(BLI_MEMARENA_STD_BUFSIZE, __func__); + } + + tris = BLI_memarena_alloc(arena, sizeof(*tris) * totfilltri); + l_arr = BLI_memarena_alloc(arena, sizeof(*l_arr) * efa->len); + projverts = BLI_memarena_alloc(arena, sizeof(*projverts) * efa->len); + + axis_dominant_v3_to_m3_negate(axis_mat, efa->no); + + j = 0; + l_iter = l_first = BM_FACE_FIRST_LOOP(efa); + do { + l_arr[j] = l_iter; + mul_v2_m3v3(projverts[j], axis_mat, l_iter->v->co); + j++; + } while ((l_iter = l_iter->next) != l_first); + + BLI_polyfill_calc_arena(projverts, efa->len, 1, tris, arena); + + for (j = 0; j < totfilltri; j++) { + BMLoop **l_ptr = looptris[i++]; + uint *tri = tris[j]; + + l_ptr[0] = l_arr[tri[0]]; + l_ptr[1] = l_arr[tri[1]]; + l_ptr[2] = l_arr[tri[2]]; + } + + BLI_memarena_clear(arena); + } + } + + if (arena) { + BLI_memarena_free(arena); + arena = NULL; + } + + BLI_assert(i <= looptris_tot); + +#undef USE_TESSFACE_SPEEDUP +} + +/** + * A version of #BM_mesh_calc_tessellation that avoids degenerate triangles. + */ +void BM_mesh_calc_tessellation_beauty(BMesh *bm, BMLoop *(*looptris)[3]) +{ +#ifndef NDEBUG + const int looptris_tot = poly_to_tri_count(bm->totface, bm->totloop); +#endif + + BMIter iter; + BMFace *efa; + int i = 0; + + MemArena *pf_arena = NULL; + + /* use_beauty */ + Heap *pf_heap = NULL; + + BM_ITER_MESH (efa, &iter, bm, BM_FACES_OF_MESH) { + BLI_assert(efa->len >= 3); + + if (efa->len == 3) { + BMLoop *l; + BMLoop **l_ptr = looptris[i++]; + l_ptr[0] = l = BM_FACE_FIRST_LOOP(efa); + l_ptr[1] = l = l->next; + l_ptr[2] = l->next; + } + else if (efa->len == 4) { + BMLoop *l_v1 = BM_FACE_FIRST_LOOP(efa); + BMLoop *l_v2 = l_v1->next; + BMLoop *l_v3 = l_v2->next; + BMLoop *l_v4 = l_v1->prev; + + /* #BM_verts_calc_rotate_beauty performs excessive checks we don't need! + * It's meant for rotating edges, it also calculates a new normal. + * + * Use #BLI_polyfill_beautify_quad_rotate_calc since we have the normal. + */ +#if 0 + const bool split_13 = (BM_verts_calc_rotate_beauty( + l_v1->v, l_v2->v, l_v3->v, l_v4->v, 0, 0) < 0.0f); +#else + float axis_mat[3][3], v_quad[4][2]; + axis_dominant_v3_to_m3(axis_mat, efa->no); + mul_v2_m3v3(v_quad[0], axis_mat, l_v1->v->co); + mul_v2_m3v3(v_quad[1], axis_mat, l_v2->v->co); + mul_v2_m3v3(v_quad[2], axis_mat, l_v3->v->co); + mul_v2_m3v3(v_quad[3], axis_mat, l_v4->v->co); + + const bool split_13 = BLI_polyfill_beautify_quad_rotate_calc( + v_quad[0], v_quad[1], v_quad[2], v_quad[3]) < 0.0f; +#endif + + BMLoop **l_ptr_a = looptris[i++]; + BMLoop **l_ptr_b = looptris[i++]; + if (split_13) { + l_ptr_a[0] = l_v1; + l_ptr_a[1] = l_v2; + l_ptr_a[2] = l_v3; + + l_ptr_b[0] = l_v1; + l_ptr_b[1] = l_v3; + l_ptr_b[2] = l_v4; + } + else { + l_ptr_a[0] = l_v1; + l_ptr_a[1] = l_v2; + l_ptr_a[2] = l_v4; + + l_ptr_b[0] = l_v2; + l_ptr_b[1] = l_v3; + l_ptr_b[2] = l_v4; + } + } + else { + int j; + + BMLoop *l_iter; + BMLoop *l_first; + BMLoop **l_arr; + + float axis_mat[3][3]; + float(*projverts)[2]; + unsigned int(*tris)[3]; + + const int totfilltri = efa->len - 2; + + if (UNLIKELY(pf_arena == NULL)) { + pf_arena = BLI_memarena_new(BLI_MEMARENA_STD_BUFSIZE, __func__); + pf_heap = BLI_heap_new_ex(BLI_POLYFILL_ALLOC_NGON_RESERVE); + } + + tris = BLI_memarena_alloc(pf_arena, sizeof(*tris) * totfilltri); + l_arr = BLI_memarena_alloc(pf_arena, sizeof(*l_arr) * efa->len); + projverts = BLI_memarena_alloc(pf_arena, sizeof(*projverts) * efa->len); + + axis_dominant_v3_to_m3_negate(axis_mat, efa->no); + + j = 0; + l_iter = l_first = BM_FACE_FIRST_LOOP(efa); + do { + l_arr[j] = l_iter; + mul_v2_m3v3(projverts[j], axis_mat, l_iter->v->co); + j++; + } while ((l_iter = l_iter->next) != l_first); + + BLI_polyfill_calc_arena(projverts, efa->len, 1, tris, pf_arena); + + BLI_polyfill_beautify(projverts, efa->len, tris, pf_arena, pf_heap); + + for (j = 0; j < totfilltri; j++) { + BMLoop **l_ptr = looptris[i++]; + unsigned int *tri = tris[j]; + + l_ptr[0] = l_arr[tri[0]]; + l_ptr[1] = l_arr[tri[1]]; + l_ptr[2] = l_arr[tri[2]]; + } + + BLI_memarena_clear(pf_arena); + } + } + + if (pf_arena) { + BLI_memarena_free(pf_arena); + + BLI_heap_free(pf_heap, NULL); + } + + BLI_assert(i <= looptris_tot); +} |