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Diffstat (limited to 'source/blender/blenlib/intern/polyfill_2d.c')
-rw-r--r-- | source/blender/blenlib/intern/polyfill_2d.c | 969 |
1 files changed, 969 insertions, 0 deletions
diff --git a/source/blender/blenlib/intern/polyfill_2d.c b/source/blender/blenlib/intern/polyfill_2d.c new file mode 100644 index 00000000000..8c0870f0c07 --- /dev/null +++ b/source/blender/blenlib/intern/polyfill_2d.c @@ -0,0 +1,969 @@ +/* + * ***** 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. + * + * ***** END GPL LICENSE BLOCK ***** + */ + +/** \file blender/blenlib/intern/polyfill_2d.c + * \ingroup bli + * + * An ear clipping algorithm to triangulate single boundary polygons. + * + * Details: + * + * - The algorithm guarantees all triangles are assigned (number of coords - 2) + * and that triangles will have non-overlapping indices (even for degenerate geometry). + * - Self-intersections are considered degenerate (resulting triangles will overlap). + * - While multiple polygons aren't supported, holes can still be defined using *key-holes* + * (where the polygon doubles back on its self with *exactly* matching coordinates). + * + * \note + * + * Changes made for Blender. + * + * - loop the array to clip last verts first (less array resizing) + * + * - advance the ear to clip each iteration + * to avoid fan-filling convex shapes (USE_CLIP_EVEN). + * + * - avoid intersection tests when there are no convex points (USE_CONVEX_SKIP). + * + * \note + * + * No globals - keep threadsafe. + */ + +#include "BLI_utildefines.h" +#include "BLI_math.h" + +#include "BLI_memarena.h" +#include "BLI_alloca.h" + +#include "BLI_polyfill_2d.h" /* own include */ + +#include "BLI_strict_flags.h" + +/* avoid fan-fill topology */ +#define USE_CLIP_EVEN +#define USE_CONVEX_SKIP +/* sweep back-and-forth about convex ears (avoids lop-sided fans) */ +#define USE_CLIP_SWEEP +// #define USE_CONVEX_SKIP_TEST + +#ifdef USE_CONVEX_SKIP +# define USE_KDTREE +#endif + +/* disable in production, it can fail on near zero area ngons */ +// #define USE_STRICT_ASSERT + +// #define DEBUG_TIME +#ifdef DEBUG_TIME +# include "PIL_time_utildefines.h" +#endif + + +typedef signed char eSign; + +#ifdef USE_KDTREE +/** + * Spatial optimization for point-in-triangle intersection checks. + * The simple version of this algorithm is ``O(n^2)`` complexity + * (every point needing to check the triangle defined by every other point), + * Using a binary-tree reduces the complexity to ``O(n log n)`` + * plus some overhead of creating the tree. + * + * This is a single purpose KDTree based on BLI_kdtree with some modifications + * to better suit polyfill2d. + * + * + * - #KDTreeNode2D is kept small (only 16 bytes), + * by not storing coords in the nodes and using index values rather then pointers + * to reference neg/pos values. + * + * - #kdtree2d_isect_tri is the only function currently used. + * This simply intersects a triangle with the kdtree points. + * + * - the KDTree is only built & used when the polygon is concave. + */ + +typedef bool axis_t; + +/* use for sorting */ +typedef struct KDTreeNode2D_head { + uint neg, pos; + uint index; +} KDTreeNode2D_head; + +typedef struct KDTreeNode2D { + uint neg, pos; + uint index; + axis_t axis; /* range is only (0-1) */ + ushort flag; + uint parent; +} KDTreeNode2D; + +struct KDTree2D { + KDTreeNode2D *nodes; + const float (*coords)[2]; + uint root; + uint totnode; + uint *nodes_map; /* index -> node lookup */ +}; + +struct KDRange2D { + float min, max; +}; +#endif /* USE_KDTREE */ + +enum { + CONCAVE = -1, + TANGENTIAL = 0, + CONVEX = 1, +}; + +typedef struct PolyFill { + struct PolyIndex *indices; /* vertex aligned */ + + const float (*coords)[2]; + uint coords_tot; +#ifdef USE_CONVEX_SKIP + uint coords_tot_concave; +#endif + + /* A polygon with n vertices has a triangulation of n-2 triangles. */ + uint (*tris)[3]; + uint tris_tot; + +#ifdef USE_KDTREE + struct KDTree2D kdtree; +#endif +} PolyFill; + + +/* circular linklist */ +typedef struct PolyIndex { + struct PolyIndex *next, *prev; + uint index; + eSign sign; +} PolyIndex; + + +/* based on libgdx 2013-11-28, apache 2.0 licensed */ + +static void pf_coord_sign_calc(PolyFill *pf, PolyIndex *pi); + +static PolyIndex *pf_ear_tip_find( + PolyFill *pf +#ifdef USE_CLIP_EVEN + , PolyIndex *pi_ear_init +#endif +#ifdef USE_CLIP_SWEEP + , bool reverse +#endif + ); + +static bool pf_ear_tip_check(PolyFill *pf, PolyIndex *pi_ear_tip); +static void pf_ear_tip_cut(PolyFill *pf, PolyIndex *pi_ear_tip); + + +BLI_INLINE eSign signum_enum(float a) +{ + if (UNLIKELY(a == 0.0f)) + return 0; + else if (a > 0.0f) + return 1; + else + return -1; +} + +/** + * alternative version of #area_tri_signed_v2 + * needed because of float precision issues + * + * \note removes / 2 since its not needed since we only need the sign. + */ +BLI_INLINE float area_tri_signed_v2_alt_2x(const float v1[2], const float v2[2], const float v3[2]) +{ + return ((v1[0] * (v2[1] - v3[1])) + + (v2[0] * (v3[1] - v1[1])) + + (v3[0] * (v1[1] - v2[1]))); +} + + +static eSign span_tri_v2_sign(const float v1[2], const float v2[2], const float v3[2]) +{ + return signum_enum(area_tri_signed_v2_alt_2x(v3, v2, v1)); +} + + +#ifdef USE_KDTREE +#define KDNODE_UNSET ((uint)-1) + +enum { + KDNODE_FLAG_REMOVED = (1 << 0), +}; + +static void kdtree2d_new( + struct KDTree2D *tree, + uint tot, + const float (*coords)[2]) +{ + /* set by caller */ + // tree->nodes = nodes; + tree->coords = coords; + tree->root = KDNODE_UNSET; + tree->totnode = tot; +} + +/** + * no need for kdtree2d_insert, since we know the coords array. + */ +static void kdtree2d_init( + struct KDTree2D *tree, + const uint coords_tot, + const PolyIndex *indices) +{ + KDTreeNode2D *node; + uint i; + + for (i = 0, node = tree->nodes; i < coords_tot; i++) { + if (indices[i].sign != CONVEX) { + node->neg = node->pos = KDNODE_UNSET; + node->index = indices[i].index; + node->axis = 0; + node->flag = 0; + node++; + } + } + + BLI_assert(tree->totnode == (uint)(node - tree->nodes)); +} + +static uint kdtree2d_balance_recursive( + KDTreeNode2D *nodes, uint totnode, axis_t axis, + const float (*coords)[2], const uint ofs) +{ + KDTreeNode2D *node; + uint neg, pos, median, i, j; + + if (totnode <= 0) { + return KDNODE_UNSET; + } + else if (totnode == 1) { + return 0 + ofs; + } + + /* quicksort style sorting around median */ + neg = 0; + pos = totnode - 1; + median = totnode / 2; + + while (pos > neg) { + const float co = coords[nodes[pos].index][axis]; + i = neg - 1; + j = pos; + + while (1) { + while (coords[nodes[++i].index][axis] < co) ; + while (coords[nodes[--j].index][axis] > co && j > neg) ; + + if (i >= j) { + break; + } + SWAP(KDTreeNode2D_head, *(KDTreeNode2D_head *)&nodes[i], *(KDTreeNode2D_head *)&nodes[j]); + } + + SWAP(KDTreeNode2D_head, *(KDTreeNode2D_head *)&nodes[i], *(KDTreeNode2D_head *)&nodes[pos]); + if (i >= median) { + pos = i - 1; + } + if (i <= median) { + neg = i + 1; + } + } + + /* set node and sort subnodes */ + node = &nodes[median]; + node->axis = axis; + axis = !axis; + node->neg = kdtree2d_balance_recursive(nodes, median, axis, coords, ofs); + node->pos = kdtree2d_balance_recursive(&nodes[median + 1], (totnode - (median + 1)), axis, coords, (median + 1) + ofs); + + return median + ofs; +} + +static void kdtree2d_balance( + struct KDTree2D *tree) +{ + tree->root = kdtree2d_balance_recursive(tree->nodes, tree->totnode, 0, tree->coords, 0); +} + + +static void kdtree2d_init_mapping( + struct KDTree2D *tree) +{ + uint i; + KDTreeNode2D *node; + + for (i = 0, node = tree->nodes; i < tree->totnode; i++, node++) { + if (node->neg != KDNODE_UNSET) { + tree->nodes[node->neg].parent = i; + } + if (node->pos != KDNODE_UNSET) { + tree->nodes[node->pos].parent = i; + } + + /* build map */ + BLI_assert(tree->nodes_map[node->index] == KDNODE_UNSET); + tree->nodes_map[node->index] = i; + } + + tree->nodes[tree->root].parent = KDNODE_UNSET; +} + +static void kdtree2d_node_remove( + struct KDTree2D *tree, + uint index) +{ + uint node_index = tree->nodes_map[index]; + KDTreeNode2D *node; + + if (node_index == KDNODE_UNSET) { + return; + } + else { + tree->nodes_map[index] = KDNODE_UNSET; + } + + node = &tree->nodes[node_index]; + tree->totnode -= 1; + + BLI_assert((node->flag & KDNODE_FLAG_REMOVED) == 0); + node->flag |= KDNODE_FLAG_REMOVED; + + while ((node->neg == KDNODE_UNSET) && + (node->pos == KDNODE_UNSET) && + (node->parent != KDNODE_UNSET)) + { + KDTreeNode2D *node_parent = &tree->nodes[node->parent]; + + BLI_assert((uint)(node - tree->nodes) == node_index); + if (node_parent->neg == node_index) { + node_parent->neg = KDNODE_UNSET; + } + else { + BLI_assert(node_parent->pos == node_index); + node_parent->pos = KDNODE_UNSET; + } + + if (node_parent->flag & KDNODE_FLAG_REMOVED) { + node_index = node->parent; + node = node_parent; + } + else { + break; + } + } +} + +static bool kdtree2d_isect_tri_recursive( + const struct KDTree2D *tree, + const uint tri_index[3], + const float *tri_coords[3], + const float tri_center[2], + const struct KDRange2D bounds[2], + const KDTreeNode2D *node) +{ + const float *co = tree->coords[node->index]; + + /* bounds then triangle intersect */ + if ((node->flag & KDNODE_FLAG_REMOVED) == 0) { + /* bounding box test first */ + if ((co[0] >= bounds[0].min) && + (co[0] <= bounds[0].max) && + (co[1] >= bounds[1].min) && + (co[1] <= bounds[1].max)) + { + if ((span_tri_v2_sign(tri_coords[0], tri_coords[1], co) != CONCAVE) && + (span_tri_v2_sign(tri_coords[1], tri_coords[2], co) != CONCAVE) && + (span_tri_v2_sign(tri_coords[2], tri_coords[0], co) != CONCAVE)) + { + if (!ELEM(node->index, tri_index[0], tri_index[1], tri_index[2])) { + return true; + } + } + } + } + +#define KDTREE2D_ISECT_TRI_RECURSE_NEG \ + (((node->neg != KDNODE_UNSET) && (co[node->axis] >= bounds[node->axis].min)) && \ + (kdtree2d_isect_tri_recursive(tree, tri_index, tri_coords, tri_center, bounds, \ + &tree->nodes[node->neg]))) +#define KDTREE2D_ISECT_TRI_RECURSE_POS \ + (((node->pos != KDNODE_UNSET) && (co[node->axis] <= bounds[node->axis].max)) && \ + (kdtree2d_isect_tri_recursive(tree, tri_index, tri_coords, tri_center, bounds, \ + &tree->nodes[node->pos]))) + + if (tri_center[node->axis] > co[node->axis]) { + if (KDTREE2D_ISECT_TRI_RECURSE_POS) { + return true; + } + if (KDTREE2D_ISECT_TRI_RECURSE_NEG) { + return true; + } + } + else { + if (KDTREE2D_ISECT_TRI_RECURSE_NEG) { + return true; + } + if (KDTREE2D_ISECT_TRI_RECURSE_POS) { + return true; + } + } + +#undef KDTREE2D_ISECT_TRI_RECURSE_NEG +#undef KDTREE2D_ISECT_TRI_RECURSE_POS + + BLI_assert(node->index != KDNODE_UNSET); + + return false; +} + +static bool kdtree2d_isect_tri( + struct KDTree2D *tree, + const uint ind[3]) +{ + const float *vs[3]; + uint i; + struct KDRange2D bounds[2] = { + {FLT_MAX, -FLT_MAX}, + {FLT_MAX, -FLT_MAX}, + }; + float tri_center[2] = {0.0f, 0.0f}; + + for (i = 0; i < 3; i++) { + vs[i] = tree->coords[ind[i]]; + + add_v2_v2(tri_center, vs[i]); + + CLAMP_MAX(bounds[0].min, vs[i][0]); + CLAMP_MIN(bounds[0].max, vs[i][0]); + CLAMP_MAX(bounds[1].min, vs[i][1]); + CLAMP_MIN(bounds[1].max, vs[i][1]); + } + + mul_v2_fl(tri_center, 1.0f / 3.0f); + + return kdtree2d_isect_tri_recursive(tree, ind, vs, tri_center, bounds, &tree->nodes[tree->root]); +} + +#endif /* USE_KDTREE */ + + +static uint *pf_tri_add(PolyFill *pf) +{ + return pf->tris[pf->tris_tot++]; +} + +static void pf_coord_remove(PolyFill *pf, PolyIndex *pi) +{ +#ifdef USE_KDTREE + /* avoid double lookups, since convex coords are ignored when testing intersections */ + if (pf->kdtree.totnode) { + kdtree2d_node_remove(&pf->kdtree, pi->index); + } +#endif + + pi->next->prev = pi->prev; + pi->prev->next = pi->next; + + if (UNLIKELY(pf->indices == pi)) { + pf->indices = pi->next; + } +#ifdef DEBUG + pi->index = (uint)-1; + pi->next = pi->prev = NULL; +#endif + + pf->coords_tot -= 1; +} + +static void pf_triangulate(PolyFill *pf) +{ + /* localize */ + PolyIndex *pi_ear; + +#ifdef USE_CLIP_EVEN + PolyIndex *pi_ear_init = pf->indices; +#endif +#ifdef USE_CLIP_SWEEP + bool reverse = false; +#endif + + while (pf->coords_tot > 3) { + PolyIndex *pi_prev, *pi_next; + eSign sign_orig_prev, sign_orig_next; + + pi_ear = pf_ear_tip_find( + pf +#ifdef USE_CLIP_EVEN + , pi_ear_init +#endif +#ifdef USE_CLIP_SWEEP + , reverse +#endif + ); + +#ifdef USE_CONVEX_SKIP + if (pi_ear->sign != CONVEX) { + pf->coords_tot_concave -= 1; + } +#endif + + pi_prev = pi_ear->prev; + pi_next = pi_ear->next; + + pf_ear_tip_cut(pf, pi_ear); + + /* The type of the two vertices adjacent to the clipped vertex may have changed. */ + sign_orig_prev = pi_prev->sign; + sign_orig_next = pi_next->sign; + + /* check if any verts became convex the (else if) + * case is highly unlikely but may happen with degenerate polygons */ + if (sign_orig_prev != CONVEX) { + pf_coord_sign_calc(pf, pi_prev); +#ifdef USE_CONVEX_SKIP + if (pi_prev->sign == CONVEX) { + pf->coords_tot_concave -= 1; +#ifdef USE_KDTREE + kdtree2d_node_remove(&pf->kdtree, pi_prev->index); +#endif + } +#endif + } + if (sign_orig_next != CONVEX) { + pf_coord_sign_calc(pf, pi_next); +#ifdef USE_CONVEX_SKIP + if (pi_next->sign == CONVEX) { + pf->coords_tot_concave -= 1; +#ifdef USE_KDTREE + kdtree2d_node_remove(&pf->kdtree, pi_next->index); +#endif + } +#endif + } + +#ifdef USE_CLIP_EVEN +#ifdef USE_CLIP_SWEEP + pi_ear_init = reverse ? pi_prev->prev : pi_next->next; +#else + pi_ear_init = pi_next->next; +#endif +#endif + +#ifdef USE_CLIP_EVEN +#ifdef USE_CLIP_SWEEP + if (pi_ear_init->sign != CONVEX) { + /* take the extra step since this ear isn't a good candidate */ + pi_ear_init = reverse ? pi_ear_init->prev : pi_ear_init->next; + reverse = !reverse; + } +#endif +#else + if ((reverse ? pi_prev->prev : pi_next->next)->sign != CONVEX) { + reverse = !reverse; + } +#endif + + } + + if (pf->coords_tot == 3) { + uint *tri = pf_tri_add(pf); + pi_ear = pf->indices; + tri[0] = pi_ear->index; pi_ear = pi_ear->next; + tri[1] = pi_ear->index; pi_ear = pi_ear->next; + tri[2] = pi_ear->index; + } +} + +/** + * \return CONCAVE, TANGENTIAL or CONVEX + */ +static void pf_coord_sign_calc(PolyFill *pf, PolyIndex *pi) +{ + /* localize */ + const float (*coords)[2] = pf->coords; + + pi->sign = span_tri_v2_sign( + coords[pi->prev->index], + coords[pi->index], + coords[pi->next->index]); +} + +static PolyIndex *pf_ear_tip_find( + PolyFill *pf +#ifdef USE_CLIP_EVEN + , PolyIndex *pi_ear_init +#endif +#ifdef USE_CLIP_SWEEP + , bool reverse +#endif + ) +{ + /* localize */ + const uint coords_tot = pf->coords_tot; + PolyIndex *pi_ear; + + uint i; + +#ifdef USE_CLIP_EVEN + pi_ear = pi_ear_init; +#else + pi_ear = pf->indices; +#endif + + i = coords_tot; + while (i--) { + if (pf_ear_tip_check(pf, pi_ear)) { + return pi_ear; + } +#ifdef USE_CLIP_SWEEP + pi_ear = reverse ? pi_ear->prev : pi_ear->next; +#else + pi_ear = pi_ear->next; +#endif + } + + /* Desperate mode: if no vertex is an ear tip, we are dealing with a degenerate polygon (e.g. nearly collinear). + * Note that the input was not necessarily degenerate, but we could have made it so by clipping some valid ears. + * + * Idea taken from Martin Held, "FIST: Fast industrial-strength triangulation of polygons", Algorithmica (1998), + * http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.115.291 + * + * Return a convex or tangential vertex if one exists. + */ + +#ifdef USE_CLIP_EVEN + pi_ear = pi_ear_init; +#else + pi_ear = pf->indices; +#endif + + i = coords_tot; + while (i--) { + if (pi_ear->sign != CONCAVE) { + return pi_ear; + } + pi_ear = pi_ear->next; + } + + /* If all vertices are concave, just return the last one. */ + return pi_ear; +} + +static bool pf_ear_tip_check(PolyFill *pf, PolyIndex *pi_ear_tip) +{ +#ifndef USE_KDTREE + /* localize */ + const float (*coords)[2] = pf->coords; + PolyIndex *pi_curr; + + const float *v1, *v2, *v3; +#endif + +#if defined(USE_CONVEX_SKIP) && !defined(USE_KDTREE) + uint coords_tot_concave_checked = 0; +#endif + + +#ifdef USE_CONVEX_SKIP + +#ifdef USE_CONVEX_SKIP_TEST + /* check if counting is wrong */ + { + uint coords_tot_concave_test = 0; + PolyIndex *pi_iter = pi_ear_tip; + do { + if (pi_iter->sign != CONVEX) { + coords_tot_concave_test += 1; + } + } while ((pi_iter = pi_iter->next) != pi_ear_tip); + BLI_assert(coords_tot_concave_test == pf->coords_tot_concave); + } +#endif + + /* fast-path for circles */ + if (pf->coords_tot_concave == 0) { + return true; + } +#endif + + if (UNLIKELY(pi_ear_tip->sign == CONCAVE)) { + return false; + } + +#ifdef USE_KDTREE + { + const uint ind[3] = { + pi_ear_tip->index, + pi_ear_tip->next->index, + pi_ear_tip->prev->index}; + + if (kdtree2d_isect_tri(&pf->kdtree, ind)) { + return false; + } + } +#else + + v1 = coords[pi_ear_tip->prev->index]; + v2 = coords[pi_ear_tip->index]; + v3 = coords[pi_ear_tip->next->index]; + + /* Check if any point is inside the triangle formed by previous, current and next vertices. + * Only consider vertices that are not part of this triangle, or else we'll always find one inside. */ + + for (pi_curr = pi_ear_tip->next->next; pi_curr != pi_ear_tip->prev; pi_curr = pi_curr->next) { + /* Concave vertices can obviously be inside the candidate ear, but so can tangential vertices + * if they coincide with one of the triangle's vertices. */ + if (pi_curr->sign != CONVEX) { + const float *v = coords[pi_curr->index]; + /* Because the polygon has clockwise winding order, + * the area sign will be positive if the point is strictly inside. + * It will be 0 on the edge, which we want to include as well. */ + + /* note: check (v3, v1) first since it fails _far_ more often then the other 2 checks (those fail equally). + * It's logical - the chance is low that points exist on the same side as the ear we're clipping off. */ + if ((span_tri_v2_sign(v3, v1, v) != CONCAVE) && + (span_tri_v2_sign(v1, v2, v) != CONCAVE) && + (span_tri_v2_sign(v2, v3, v) != CONCAVE)) + { + return false; + } + +#ifdef USE_CONVEX_SKIP + coords_tot_concave_checked += 1; + if (coords_tot_concave_checked == pf->coords_tot_concave) { + break; + } +#endif + } + } +#endif /* USE_KDTREE */ + + return true; +} + +static void pf_ear_tip_cut(PolyFill *pf, PolyIndex *pi_ear_tip) +{ + uint *tri = pf_tri_add(pf); + + tri[0] = pi_ear_tip->prev->index; + tri[1] = pi_ear_tip->index; + tri[2] = pi_ear_tip->next->index; + + pf_coord_remove(pf, pi_ear_tip); +} + +/** + * Initializes the #PolyFill structure before tessellating with #polyfill_calc. + */ +static void polyfill_prepare( + PolyFill *pf, + const float (*coords)[2], + const uint coords_tot, + int coords_sign, + uint (*r_tris)[3], + PolyIndex *r_indices) +{ + /* localize */ + PolyIndex *indices = r_indices; + + uint i; + + /* assign all polyfill members here */ + pf->indices = r_indices; + pf->coords = coords; + pf->coords_tot = coords_tot; +#ifdef USE_CONVEX_SKIP + pf->coords_tot_concave = 0; +#endif + pf->tris = r_tris; + pf->tris_tot = 0; + + if (coords_sign == 0) { + coords_sign = (cross_poly_v2(coords, coords_tot) >= 0.0f) ? 1 : -1; + } + else { + /* check we're passing in correcty args */ +#ifdef USE_STRICT_ASSERT +#ifndef NDEBUG + if (coords_sign == 1) { + BLI_assert(cross_poly_v2(coords, coords_tot) >= 0.0f); + } + else { + BLI_assert(cross_poly_v2(coords, coords_tot) <= 0.0f); + } +#endif +#endif + } + + if (coords_sign == 1) { + for (i = 0; i < coords_tot; i++) { + indices[i].next = &indices[i + 1]; + indices[i].prev = &indices[i - 1]; + indices[i].index = i; + } + } + else { + /* reversed */ + uint n = coords_tot - 1; + for (i = 0; i < coords_tot; i++) { + indices[i].next = &indices[i + 1]; + indices[i].prev = &indices[i - 1]; + indices[i].index = (n - i); + } + } + indices[0].prev = &indices[coords_tot - 1]; + indices[coords_tot - 1].next = &indices[0]; + + for (i = 0; i < coords_tot; i++) { + PolyIndex *pi = &indices[i]; + pf_coord_sign_calc(pf, pi); +#ifdef USE_CONVEX_SKIP + if (pi->sign != CONVEX) { + pf->coords_tot_concave += 1; + } +#endif + } +} + +static void polyfill_calc( + PolyFill *pf) +{ +#ifdef USE_KDTREE +#ifdef USE_CONVEX_SKIP + if (pf->coords_tot_concave) +#endif + { + kdtree2d_new(&pf->kdtree, pf->coords_tot_concave, pf->coords); + kdtree2d_init(&pf->kdtree, pf->coords_tot, pf->indices); + kdtree2d_balance(&pf->kdtree); + kdtree2d_init_mapping(&pf->kdtree); + } +#endif + + pf_triangulate(pf); +} + +/** + * A version of #BLI_polyfill_calc that uses a memory arena to avoid re-allocations. + */ +void BLI_polyfill_calc_arena( + const float (*coords)[2], + const uint coords_tot, + const int coords_sign, + uint (*r_tris)[3], + + struct MemArena *arena) +{ + PolyFill pf; + PolyIndex *indices = BLI_memarena_alloc(arena, sizeof(*indices) * coords_tot); + +#ifdef DEBUG_TIME + TIMEIT_START(polyfill2d); +#endif + + polyfill_prepare( + &pf, + coords, coords_tot, coords_sign, + r_tris, + /* cache */ + indices); + +#ifdef USE_KDTREE + if (pf.coords_tot_concave) { + pf.kdtree.nodes = BLI_memarena_alloc(arena, sizeof(*pf.kdtree.nodes) * pf.coords_tot_concave); + pf.kdtree.nodes_map = memset(BLI_memarena_alloc(arena, sizeof(*pf.kdtree.nodes_map) * coords_tot), + 0xff, sizeof(*pf.kdtree.nodes_map) * coords_tot); + } + else { + pf.kdtree.totnode = 0; + } +#endif + + polyfill_calc(&pf); + + /* indices are no longer needed, + * caller can clear arena */ + +#ifdef DEBUG_TIME + TIMEIT_END(polyfill2d); +#endif +} + +/** + * Triangulates the given (convex or concave) simple polygon to a list of triangle vertices. + * + * \param coords: 2D coordinates describing vertices of the polygon, + * in either clockwise or counterclockwise order. + * \param coords_tot: Total points in the array. + * \param coords_sign: Pass this when we know the sign in advance to avoid extra calculations. + * + * \param r_tris: This array is filled in with triangle indices in clockwise order. + * The length of the array must be ``coords_tot - 2``. + * Indices are guaranteed to be assigned to unique triangles, with valid indices, + * even in the case of degenerate input (self intersecting polygons, zero area ears... etc). + */ +void BLI_polyfill_calc( + const float (*coords)[2], + const uint coords_tot, + const int coords_sign, + uint (*r_tris)[3]) +{ + PolyFill pf; + PolyIndex *indices = BLI_array_alloca(indices, coords_tot); + +#ifdef DEBUG_TIME + TIMEIT_START(polyfill2d); +#endif + + polyfill_prepare( + &pf, + coords, coords_tot, coords_sign, + r_tris, + /* cache */ + indices); + +#ifdef USE_KDTREE + if (pf.coords_tot_concave) { + pf.kdtree.nodes = BLI_array_alloca(pf.kdtree.nodes, pf.coords_tot_concave); + pf.kdtree.nodes_map = memset(BLI_array_alloca(pf.kdtree.nodes_map, coords_tot), + 0xff, sizeof(*pf.kdtree.nodes_map) * coords_tot); + } + else { + pf.kdtree.totnode = 0; + } +#endif + + polyfill_calc(&pf); + +#ifdef DEBUG_TIME + TIMEIT_END(polyfill2d); +#endif +} |