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Diffstat (limited to 'source/blender/bmesh/tools/bmesh_decimate_unsubdivide.c')
| -rw-r--r-- | source/blender/bmesh/tools/bmesh_decimate_unsubdivide.c | 344 |
1 files changed, 344 insertions, 0 deletions
diff --git a/source/blender/bmesh/tools/bmesh_decimate_unsubdivide.c b/source/blender/bmesh/tools/bmesh_decimate_unsubdivide.c new file mode 100644 index 00000000000..acdab2510a4 --- /dev/null +++ b/source/blender/bmesh/tools/bmesh_decimate_unsubdivide.c @@ -0,0 +1,344 @@ +/* + * ***** 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): Campbell Barton + * + * ***** END GPL LICENSE BLOCK ***** + */ + +/** \file blender/bmesh/tools/bmesh_decimate_unsubdivide.c + * \ingroup bmesh + * + * BMesh decimator that uses a grid un-subdivide method. + */ + + +#include "MEM_guardedalloc.h" + +#include "BLI_math.h" + +#include "bmesh.h" + +#include "intern/bmesh_operators_private.h" /* own include */ + + +static int bm_vert_dissolve_fan_test(BMVert *v) +{ + /* check if we should walk over these verts */ + BMIter iter; + BMEdge *e; + + unsigned int tot_edge = 0; + unsigned int tot_edge_boundary = 0; + unsigned int tot_edge_manifold = 0; + unsigned int tot_edge_wire = 0; + + BM_ITER_ELEM (e, &iter, v, BM_EDGES_OF_VERT) { + if (BM_edge_is_boundary(e)) { + tot_edge_boundary++; + } + else if (BM_edge_is_manifold(e)) { + tot_edge_manifold++; + } + else if (BM_edge_is_wire(e)) { + tot_edge_wire++; + } + tot_edge++; + } + + if ((tot_edge == 4) && (tot_edge_boundary == 0) && (tot_edge_manifold == 4)) { + return TRUE; + } + else if ((tot_edge == 3) && (tot_edge_boundary == 0) && (tot_edge_manifold == 3)) { + return TRUE; + } + else if ((tot_edge == 3) && (tot_edge_boundary == 2) && (tot_edge_manifold == 1)) { + return TRUE; + } + else if ((tot_edge == 2) && (tot_edge_wire == 2)) { + return TRUE; + } + return FALSE; +} + +static int bm_vert_dissolve_fan(BMesh *bm, BMVert *v) +{ + /* collapse under 2 conditions. + * - vert connects to 4 manifold edges (and 4 faces). + * - vert connecrs to 1 manifold edge, 2 boundary edges (and 2 faces). + * + * This covers boundary verts of a quad grid and center verts. + * note that surrounding faces dont have to be quads. + */ + + BMIter iter; + BMEdge *e; + + unsigned int tot_loop = 0; + unsigned int tot_edge = 0; + unsigned int tot_edge_boundary = 0; + unsigned int tot_edge_manifold = 0; + unsigned int tot_edge_wire = 0; + + BM_ITER_ELEM (e, &iter, v, BM_EDGES_OF_VERT) { + if (BM_edge_is_boundary(e)) { + tot_edge_boundary++; + } + else if (BM_edge_is_manifold(e)) { + tot_edge_manifold++; + } + else if (BM_edge_is_wire(e)) { + tot_edge_wire++; + } + tot_edge++; + } + + if (tot_edge == 2) { + /* check for 2 wire verts only */ + if (tot_edge_wire == 2) { + return (BM_vert_collapse_edge(bm, v->e, v, TRUE) != NULL); + } + } + else if (tot_edge == 4) { + /* check for 4 faces surrounding */ + if (tot_edge_boundary == 0 && tot_edge_manifold == 4) { + /* good to go! */ + tot_loop = 4; + } + } + else if (tot_edge == 3) { + /* check for 2 faces surrounding at a boundary */ + if (tot_edge_boundary == 2 && tot_edge_manifold == 1) { + /* good to go! */ + tot_loop = 2; + } + else if (tot_edge_boundary == 0 && tot_edge_manifold == 3) { + /* good to go! */ + tot_loop = 3; + } + } + + if (tot_loop) { + BMLoop *f_loop[4]; + unsigned int i; + + /* ensure there are exactly tot_loop loops */ + BLI_assert(BM_iter_at_index(bm, BM_LOOPS_OF_VERT, v, tot_loop) == NULL); + BM_iter_as_array(bm, BM_LOOPS_OF_VERT, v, (void **)f_loop, tot_loop); + + for (i = 0; i < tot_loop; i++) { + BMLoop *l = f_loop[i]; + if (l->f->len > 3) { + BMLoop *l_new; + BLI_assert(l->prev->v != l->next->v); + BM_face_split(bm, l->f, l->prev->v, l->next->v, &l_new, NULL, TRUE); + BM_elem_flag_merge_into(l_new->e, l->e, l->prev->e); + } + } + + return BM_vert_dissolve(bm, v); + } + + return FALSE; +} + +enum { + VERT_INDEX_DO_COLLAPSE = -1, + VERT_INDEX_INIT = 0, + VERT_INDEX_IGNORE = 1 +}; + +// #define USE_WALKER /* gives uneven results, disable for now */ + +/* - BMVert.flag & BM_ELEM_TAG: shows we touched this vert + * - BMVert.index == -1: shows we will remove this vert + */ + +/** + * \param tag_only so we can call this from an operator */ +void BM_mesh_decimate_unsubdivide_ex(BMesh *bm, const int iterations, const int tag_only) +{ +#ifdef USE_WALKER +# define ELE_VERT_TAG 1 +#else + BMVert **vert_seek_a = MEM_mallocN(sizeof(BMVert *) * bm->totvert, __func__); + BMVert **vert_seek_b = MEM_mallocN(sizeof(BMVert *) * bm->totvert, __func__); + unsigned vert_seek_a_tot = 0; + unsigned vert_seek_b_tot = 0; +#endif + + BMVert *v; + BMIter iter; + + const unsigned int offset = 0; + const unsigned int nth = 2; + + int iter_step; + + /* if tag_only is set, we assyme the caller knows what verts to tag + * needed for the operator */ + if (tag_only == FALSE) { + BM_ITER_MESH (v, &iter, bm, BM_VERTS_OF_MESH) { + BM_elem_flag_enable(v, BM_ELEM_TAG); + } + } + + for (iter_step = 0; iter_step < iterations; iter_step++) { + int iter_done; + + BM_ITER_MESH (v, &iter, bm, BM_VERTS_OF_MESH) { + if (BM_elem_flag_test(v, BM_ELEM_TAG) && bm_vert_dissolve_fan_test(v)) { +#ifdef USE_WALKER + BMO_elem_flag_enable(bm, v, ELE_VERT_TAG); +#endif + BM_elem_index_set(v, VERT_INDEX_INIT); /* set_dirty! */ + } + else { + BM_elem_index_set(v, VERT_INDEX_IGNORE); /* set_dirty! */ + } + } + /* done with selecting tagged verts */ + + + /* main loop, keep tagging until we can't tag any more islands */ + while (TRUE) { +#ifdef USE_WALKER + BMWalker walker; +#else + unsigned int depth = 1; + unsigned int i; +#endif + BMVert *v_first = NULL; + BMVert *v; + + /* we could avoid iterating from the start each time */ + BM_ITER_MESH (v, &iter, bm, BM_VERTS_OF_MESH) { + if (v->e && (BM_elem_index_get(v) == VERT_INDEX_INIT)) { +#ifdef USE_WALKER + if (BMO_elem_flag_test(bm, v, ELE_VERT_TAG)) +#endif + { + /* check again incase the topology changed */ + if (bm_vert_dissolve_fan_test(v)) { + v_first = v; + } + break; + } + } + } + if (v_first == NULL) { + break; + } + +#ifdef USE_WALKER + /* Walk over selected elements starting at active */ + BMW_init(&walker, bm, BMW_CONNECTED_VERTEX, + ELE_VERT_TAG, BMW_MASK_NOP, BMW_MASK_NOP, + BMW_FLAG_NOP, /* don't use BMW_FLAG_TEST_HIDDEN here since we want to desel all */ + BMW_NIL_LAY); + + BLI_assert(walker.order == BMW_BREADTH_FIRST); + for (v = BMW_begin(&walker, v_first); v != NULL; v = BMW_step(&walker)) { + /* Deselect elements that aren't at "nth" depth from active */ + if (BM_elem_index_get(v) == VERT_INDEX_INIT) { + if ((offset + BMW_current_depth(&walker)) % nth) { + /* tag for removal */ + BM_elem_index_set(v, VERT_INDEX_DO_COLLAPSE); /* set_dirty! */ + } + else { + /* works better to allow these verts to be checked again */ + //BM_elem_index_set(v, VERT_INDEX_IGNORE); /* set_dirty! */ + } + } + } + BMW_end(&walker); +#else + + BM_elem_index_set(v_first, (offset + depth) % nth ? VERT_INDEX_IGNORE : VERT_INDEX_DO_COLLAPSE); /* set_dirty! */ + + vert_seek_b_tot = 0; + vert_seek_b[vert_seek_b_tot++] = v_first; + + while (TRUE) { + BMEdge *e; + + if ((offset + depth) % nth) { + vert_seek_a_tot = 0; + for (i = 0; i < vert_seek_b_tot; i++) { + v = vert_seek_b[i]; + BLI_assert(BM_elem_index_get(v) == VERT_INDEX_IGNORE); + BM_ITER_ELEM (e, &iter, v, BM_EDGES_OF_VERT) { + BMVert *v_other = BM_edge_other_vert(e, v); + if (BM_elem_index_get(v_other) == VERT_INDEX_INIT) { + BM_elem_index_set(v_other, VERT_INDEX_DO_COLLAPSE); /* set_dirty! */ + vert_seek_a[vert_seek_a_tot++] = v_other; + } + } + } + if (vert_seek_a_tot == 0) { + break; + } + } + else { + vert_seek_b_tot = 0; + for (i = 0; i < vert_seek_a_tot; i++) { + v = vert_seek_a[i]; + BLI_assert(BM_elem_index_get(v) == VERT_INDEX_DO_COLLAPSE); + BM_ITER_ELEM (e, &iter, v, BM_EDGES_OF_VERT) { + BMVert *v_other = BM_edge_other_vert(e, v); + if (BM_elem_index_get(v_other) == VERT_INDEX_INIT) { + BM_elem_index_set(v_other, VERT_INDEX_IGNORE); /* set_dirty! */ + vert_seek_b[vert_seek_b_tot++] = v_other; + } + } + } + if (vert_seek_b_tot == 0) { + break; + } + } + + depth++; + } +#endif /* USE_WALKER */ + + } + + /* now we tagged all verts -1 for removal, lets loop over and rebuild faces */ + iter_done = FALSE; + BM_ITER_MESH (v, &iter, bm, BM_VERTS_OF_MESH) { + if (BM_elem_index_get(v) == VERT_INDEX_DO_COLLAPSE) { + iter_done |= bm_vert_dissolve_fan(bm, v); + } + } + + if (iter_done == FALSE) { + break; + } + } + + bm->elem_index_dirty |= BM_VERT; + +#ifndef USE_WALKER + MEM_freeN(vert_seek_a); + MEM_freeN(vert_seek_b); +#endif +} + +void BM_mesh_decimate_unsubdivide(BMesh *bm, const int iterations) +{ + BM_mesh_decimate_unsubdivide_ex(bm, iterations, FALSE); +} |