blender-archive/source/blender/blenkernel/intern/mesh_validate.c

/*
 * 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.
 *
 * The Original Code is Copyright (C) 2011 Blender Foundation.
 * All rights reserved.
 */

/** \file \ingroup bke
 */


#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>

#include "CLG_log.h"

#include "DNA_mesh_types.h"
#include "DNA_meshdata_types.h"
#include "DNA_object_types.h"

#include "BLI_sys_types.h"

#include "BLI_utildefines.h"
#include "BLI_edgehash.h"
#include "BLI_math_base.h"
#include "BLI_math_vector.h"

#include "BKE_deform.h"
#include "BKE_mesh.h"

#include "DEG_depsgraph.h"

#include "MEM_guardedalloc.h"

/* loop v/e are unsigned, so using max uint_32 value as invalid marker... */
#define INVALID_LOOP_EDGE_MARKER 4294967295u

static CLG_LogRef LOG = {"bke.mesh"};

/** \name Internal functions
 * \{ */

typedef union {
	uint32_t verts[2];
	int64_t edval;
} EdgeUUID;

typedef struct SortFace {
	EdgeUUID     es[4];
	unsigned int index;
} SortFace;

/* Used to detect polys (faces) using exactly the same vertices. */
/* Used to detect loops used by no (disjoint) or more than one (intersect) polys. */
typedef struct SortPoly {
	int *verts;
	int numverts;
	int loopstart;
	unsigned int index;
	bool invalid;  /* Poly index. */
} SortPoly;

static void edge_store_assign(uint32_t verts[2],  const uint32_t v1, const uint32_t v2)
{
	if (v1 < v2) {
		verts[0] = v1;
		verts[1] = v2;
	}
	else {
		verts[0] = v2;
		verts[1] = v1;
	}
}

static void edge_store_from_mface_quad(EdgeUUID es[4], MFace *mf)
{
	edge_store_assign(es[0].verts, mf->v1, mf->v2);
	edge_store_assign(es[1].verts, mf->v2, mf->v3);
	edge_store_assign(es[2].verts, mf->v3, mf->v4);
	edge_store_assign(es[3].verts, mf->v4, mf->v1);
}

static void edge_store_from_mface_tri(EdgeUUID es[4], MFace *mf)
{
	edge_store_assign(es[0].verts, mf->v1, mf->v2);
	edge_store_assign(es[1].verts, mf->v2, mf->v3);
	edge_store_assign(es[2].verts, mf->v3, mf->v1);
	es[3].verts[0] = es[3].verts[1] = UINT_MAX;
}

static int int64_cmp(const void *v1, const void *v2)
{
	const int64_t x1 = *(const int64_t *)v1;
	const int64_t x2 = *(const int64_t *)v2;

	if (x1 > x2) {
		return 1;
	}
	else if (x1 < x2) {
		return -1;
	}

	return 0;
}

static int search_face_cmp(const void *v1, const void *v2)
{
	const SortFace *sfa = v1, *sfb = v2;

	if (sfa->es[0].edval > sfb->es[0].edval) {
		return 1;
	}
	else if (sfa->es[0].edval < sfb->es[0].edval) {
		return -1;
	}

	else if (sfa->es[1].edval > sfb->es[1].edval) {
		return 1;
	}
	else if (sfa->es[1].edval < sfb->es[1].edval) {
		return -1;
	}

	else if (sfa->es[2].edval > sfb->es[2].edval) {
		return 1;
	}
	else if (sfa->es[2].edval < sfb->es[2].edval) {
		return -1;
	}

	else if (sfa->es[3].edval > sfb->es[3].edval) {
		return 1;
	}
	else if (sfa->es[3].edval < sfb->es[3].edval) {
		return -1;
	}

	return 0;
}

/* TODO check there is not some standard define of this somewhere! */
static int int_cmp(const void *v1, const void *v2)
{
	return *(int *)v1 > *(int *)v2 ? 1 : *(int *)v1 < *(int *)v2 ? -1 : 0;
}

static int search_poly_cmp(const void *v1, const void *v2)
{
	const SortPoly *sp1 = v1, *sp2 = v2;
	const int max_idx = sp1->numverts > sp2->numverts ? sp2->numverts : sp1->numverts;
	int idx;

	/* Reject all invalid polys at end of list! */
	if (sp1->invalid || sp2->invalid)
		return sp1->invalid ? (sp2->invalid ? 0 : 1) : -1;
	/* Else, sort on first non-equal verts (remember verts of valid polys are sorted). */
	for (idx = 0; idx < max_idx; idx++) {
		const int v1_i = sp1->verts[idx];
		const int v2_i = sp2->verts[idx];
		if (v1_i != v2_i) {
			return (v1_i > v2_i) ? 1 : -1;
		}
	}
	return sp1->numverts > sp2->numverts ? 1 : sp1->numverts < sp2->numverts ? -1 : 0;
}

static int search_polyloop_cmp(const void *v1, const void *v2)
{
	const SortPoly *sp1 = v1, *sp2 = v2;

	/* Reject all invalid polys at end of list! */
	if (sp1->invalid || sp2->invalid)
		return sp1->invalid && sp2->invalid ? 0 : sp1->invalid ? 1 : -1;
	/* Else, sort on loopstart. */
	return sp1->loopstart > sp2->loopstart ? 1 : sp1->loopstart < sp2->loopstart ? -1 : 0;
}
/** \} */



/* -------------------------------------------------------------------- */
/** \name Mesh Validation
 * \{ */

#define PRINT_MSG(...) if(do_verbose) CLOG_INFO(&LOG, 1, __VA_ARGS__)

#define PRINT_ERR(...) do { \
		is_valid = false; \
		if (do_verbose) { CLOG_ERROR(&LOG, __VA_ARGS__); } \
	} while(0)

/**
 * Validate the mesh, \a do_fixes requires \a mesh to be non-null.
 *
 * \return false if no changes needed to be made.
 */
bool BKE_mesh_validate_arrays(
        Mesh *mesh,
        MVert *mverts, unsigned int totvert,
        MEdge *medges, unsigned int totedge,
        MFace *mfaces, unsigned int totface,
        MLoop *mloops, unsigned int totloop,
        MPoly *mpolys, unsigned int totpoly,
        MDeformVert *dverts, /* assume totvert length */
        const bool do_verbose, const bool do_fixes,
        bool *r_changed)
{
#define REMOVE_EDGE_TAG(_me) { _me->v2 = _me->v1; free_flag.edges = do_fixes; } (void)0
#define IS_REMOVED_EDGE(_me) (_me->v2 == _me->v1)

#define REMOVE_LOOP_TAG(_ml) { _ml->e = INVALID_LOOP_EDGE_MARKER; free_flag.polyloops = do_fixes; } (void)0
#define REMOVE_POLY_TAG(_mp) { _mp->totloop *= -1; free_flag.polyloops = do_fixes; } (void)0

	MVert *mv = mverts;
	MEdge *me;
	MLoop *ml;
	MPoly *mp;
	unsigned int i, j;
	int *v;

	bool is_valid = true;

	union {
		struct {
			int verts : 1;
			int verts_weight : 1;
			int loops_edge : 1;
		};
		int as_flag;
	} fix_flag;

	union {
		struct {
			int edges : 1;
			int faces : 1;
			/* This regroups loops and polys! */
			int polyloops : 1;
			int mselect : 1;
		};
		int as_flag;
	} free_flag;

	union {
		struct {
			int edges : 1;
		};
		int as_flag;
	} recalc_flag;

	EdgeHash *edge_hash = BLI_edgehash_new_ex(__func__, totedge);

	BLI_assert(!(do_fixes && mesh == NULL));

	fix_flag.as_flag = 0;
	free_flag.as_flag = 0;
	recalc_flag.as_flag = 0;

	PRINT_MSG("verts(%u), edges(%u), loops(%u), polygons(%u)",
	          totvert, totedge, totloop, totpoly);

	if (totedge == 0 && totpoly != 0) {
		PRINT_ERR("\tLogical error, %u polygons and 0 edges", totpoly);
		recalc_flag.edges = do_fixes;
	}

	for (i = 0; i < totvert; i++, mv++) {
		bool fix_normal = true;

		for (j = 0; j < 3; j++) {
			if (!isfinite(mv->co[j])) {
				PRINT_ERR("\tVertex %u: has invalid coordinate", i);

				if (do_fixes) {
					zero_v3(mv->co);

					fix_flag.verts = true;
				}
			}

			if (mv->no[j] != 0)
				fix_normal = false;
		}

		if (fix_normal) {
			PRINT_ERR("\tVertex %u: has zero normal, assuming Z-up normal", i);
			if (do_fixes) {
				mv->no[2] = SHRT_MAX;
				fix_flag.verts = true;
			}
		}
	}

	for (i = 0, me = medges; i < totedge; i++, me++) {
		bool remove = false;

		if (me->v1 == me->v2) {
			PRINT_ERR("\tEdge %u: has matching verts, both %u", i, me->v1);
			remove = do_fixes;
		}
		if (me->v1 >= totvert) {
			PRINT_ERR("\tEdge %u: v1 index out of range, %u", i, me->v1);
			remove = do_fixes;
		}
		if (me->v2 >= totvert) {
			PRINT_ERR("\tEdge %u: v2 index out of range, %u", i, me->v2);
			remove = do_fixes;
		}

		if ((me->v1 != me->v2) && BLI_edgehash_haskey(edge_hash, me->v1, me->v2)) {
			PRINT_ERR("\tEdge %u: is a duplicate of %d", i,
			          POINTER_AS_INT(BLI_edgehash_lookup(edge_hash, me->v1, me->v2)));
			remove = do_fixes;
		}

		if (remove == false) {
			if (me->v1 != me->v2) {
				BLI_edgehash_insert(edge_hash, me->v1, me->v2, POINTER_FROM_INT(i));
			}
		}
		else {
			REMOVE_EDGE_TAG(me);
		}
	}

	if (mfaces && !mpolys) {
#		define REMOVE_FACE_TAG(_mf) { _mf->v3 = 0; free_flag.faces = do_fixes; } (void)0
#		define CHECK_FACE_VERT_INDEX(a, b) \
					if (mf->a == mf->b) { \
						PRINT_ERR("    face %u: verts invalid, " STRINGIFY(a) "/" STRINGIFY(b) " both %u", i, mf->a); \
						remove = do_fixes; \
					} (void)0
#		define CHECK_FACE_EDGE(a, b) \
					if (!BLI_edgehash_haskey(edge_hash, mf->a, mf->b)) { \
						PRINT_ERR("    face %u: edge " STRINGIFY(a) "/" STRINGIFY(b) \
						          " (%u,%u) is missing edge data", i, mf->a, mf->b); \
						recalc_flag.edges = do_fixes; \
					} (void)0

		MFace *mf;
		MFace *mf_prev;

		SortFace *sort_faces = MEM_callocN(sizeof(SortFace) * totface, "search faces");
		SortFace *sf;
		SortFace *sf_prev;
		unsigned int totsortface = 0;

		PRINT_ERR("No Polys, only tessellated Faces");

		for (i = 0, mf = mfaces, sf = sort_faces; i < totface; i++, mf++) {
			bool remove = false;
			int fidx;
			unsigned int fv[4];

			fidx = mf->v4 ? 3 : 2;
			do {
				fv[fidx] = *(&(mf->v1) + fidx);
				if (fv[fidx] >= totvert) {
					PRINT_ERR("\tFace %u: 'v%d' index out of range, %u", i, fidx + 1, fv[fidx]);
					remove = do_fixes;
				}
			} while (fidx--);

			if (remove == false) {
				if (mf->v4) {
					CHECK_FACE_VERT_INDEX(v1, v2);
					CHECK_FACE_VERT_INDEX(v1, v3);
					CHECK_FACE_VERT_INDEX(v1, v4);

					CHECK_FACE_VERT_INDEX(v2, v3);
					CHECK_FACE_VERT_INDEX(v2, v4);

					CHECK_FACE_VERT_INDEX(v3, v4);
				}
				else {
					CHECK_FACE_VERT_INDEX(v1, v2);
					CHECK_FACE_VERT_INDEX(v1, v3);

					CHECK_FACE_VERT_INDEX(v2, v3);
				}

				if (remove == false) {
					if (totedge) {
						if (mf->v4) {
							CHECK_FACE_EDGE(v1, v2);
							CHECK_FACE_EDGE(v2, v3);
							CHECK_FACE_EDGE(v3, v4);
							CHECK_FACE_EDGE(v4, v1);
						}
						else {
							CHECK_FACE_EDGE(v1, v2);
							CHECK_FACE_EDGE(v2, v3);
							CHECK_FACE_EDGE(v3, v1);
						}
					}

					sf->index = i;

					if (mf->v4) {
						edge_store_from_mface_quad(sf->es, mf);

						qsort(sf->es, 4, sizeof(int64_t), int64_cmp);
					}
					else {
						edge_store_from_mface_tri(sf->es, mf);
						qsort(sf->es, 3, sizeof(int64_t), int64_cmp);
					}

					totsortface++;
					sf++;
				}
			}

			if (remove) {
				REMOVE_FACE_TAG(mf);
			}
		}

		qsort(sort_faces, totsortface, sizeof(SortFace), search_face_cmp);

		sf = sort_faces;
		sf_prev = sf;
		sf++;

		for (i = 1; i < totsortface; i++, sf++) {
			bool remove = false;

			/* on a valid mesh, code below will never run */
			if (memcmp(sf->es, sf_prev->es, sizeof(sf_prev->es)) == 0) {
				mf = mfaces + sf->index;

				if (do_verbose) {
					mf_prev = mfaces + sf_prev->index;

					if (mf->v4) {
						PRINT_ERR("\tFace %u & %u: are duplicates (%u,%u,%u,%u) (%u,%u,%u,%u)",
						          sf->index, sf_prev->index, mf->v1, mf->v2, mf->v3, mf->v4,
						          mf_prev->v1, mf_prev->v2, mf_prev->v3, mf_prev->v4);
					}
					else {
						PRINT_ERR("\tFace %u & %u: are duplicates (%u,%u,%u) (%u,%u,%u)",
						          sf->index, sf_prev->index, mf->v1, mf->v2, mf->v3,
						          mf_prev->v1, mf_prev->v2, mf_prev->v3);
					}
				}

				remove = do_fixes;
			}
			else {
				sf_prev = sf;
			}

			if (remove) {
				REMOVE_FACE_TAG(mf);
			}
		}

		MEM_freeN(sort_faces);

#		undef REMOVE_FACE_TAG
#		undef CHECK_FACE_VERT_INDEX
#		undef CHECK_FACE_EDGE
	}

	/* Checking loops and polys is a bit tricky, as they are quite intricate...
	 *
	 * Polys must have:
	 * - a valid loopstart value.
	 * - a valid totloop value (>= 3 and loopstart+totloop < me.totloop).
	 *
	 * Loops must have:
	 * - a valid v value.
	 * - a valid e value (corresponding to the edge it defines with the next loop in poly).
	 *
	 * Also, loops not used by polys can be discarded.
	 * And "intersecting" loops (i.e. loops used by more than one poly) are invalid,
	 * so be sure to leave at most one poly per loop!
	 */
	{
		SortPoly *sort_polys = MEM_callocN(sizeof(SortPoly) * totpoly, "mesh validate's sort_polys");
		SortPoly *prev_sp, *sp = sort_polys;
		int prev_end;

		for (i = 0, mp = mpolys; i < totpoly; i++, mp++, sp++) {
			sp->index = i;

			if (mp->loopstart < 0 || mp->totloop < 3) {
				/* Invalid loop data. */
				PRINT_ERR("\tPoly %u is invalid (loopstart: %d, totloop: %d)",
				          sp->index, mp->loopstart, mp->totloop);
				sp->invalid = true;
			}
			else if (mp->loopstart + mp->totloop > totloop) {
				/* Invalid loop data. */
				PRINT_ERR("\tPoly %u uses loops out of range (loopstart: %d, loopend: %d, max nbr of loops: %u)",
				          sp->index, mp->loopstart, mp->loopstart + mp->totloop - 1, totloop - 1);
				sp->invalid = true;
			}
			else {
				/* Poly itself is valid, for now. */
				int v1, v2; /* v1 is prev loop vert idx, v2 is current loop one. */
				sp->invalid = false;
				sp->verts = v = MEM_mallocN(sizeof(int) * mp->totloop, "Vert idx of SortPoly");
				sp->numverts = mp->totloop;
				sp->loopstart = mp->loopstart;

				/* Ideally we would only have to do that once on all vertices before we start checking each poly, but
				 * several polys can use same vert, so we have to ensure here all verts of current poly are cleared. */
				for (j = 0, ml = &mloops[sp->loopstart]; j < mp->totloop; j++, ml++) {
					if (ml->v < totvert) {
						mverts[ml->v].flag &= ~ME_VERT_TMP_TAG;
					}
				}

				/* Test all poly's loops' vert idx. */
				for (j = 0, ml = &mloops[sp->loopstart]; j < mp->totloop; j++, ml++, v++) {
					if (ml->v >= totvert) {
						/* Invalid vert idx. */
						PRINT_ERR("\tLoop %u has invalid vert reference (%u)", sp->loopstart + j, ml->v);
						sp->invalid = true;
					}
					else if (mverts[ml->v].flag & ME_VERT_TMP_TAG) {
						PRINT_ERR("\tPoly %u has duplicated vert reference at corner (%u)", i, j);
						sp->invalid = true;
					}
					else {
						mverts[ml->v].flag |= ME_VERT_TMP_TAG;
					}
					*v = ml->v;
				}

				if (sp->invalid)
					continue;

				/* Test all poly's loops. */
				for (j = 0, ml = &mloops[sp->loopstart]; j < mp->totloop; j++, ml++) {
					v1 = ml->v;
					v2 = mloops[sp->loopstart + (j + 1) % mp->totloop].v;
					if (!BLI_edgehash_haskey(edge_hash, v1, v2)) {
						/* Edge not existing. */
						PRINT_ERR("\tPoly %u needs missing edge (%d, %d)", sp->index, v1, v2);
						if (do_fixes)
							recalc_flag.edges = true;
						else
							sp->invalid = true;
					}
					else if (ml->e >= totedge) {
						/* Invalid edge idx.
						 * We already know from previous text that a valid edge exists, use it (if allowed)! */
						if (do_fixes) {
							int prev_e = ml->e;
							ml->e = POINTER_AS_INT(BLI_edgehash_lookup(edge_hash, v1, v2));
							fix_flag.loops_edge = true;
							PRINT_ERR("\tLoop %u has invalid edge reference (%d), fixed using edge %u",
							          sp->loopstart + j, prev_e, ml->e);
						}
						else {
							PRINT_ERR("\tLoop %u has invalid edge reference (%u)", sp->loopstart + j, ml->e);
							sp->invalid = true;
						}
					}
					else {
						me = &medges[ml->e];
						if (IS_REMOVED_EDGE(me) || !((me->v1 == v1 && me->v2 == v2) || (me->v1 == v2 && me->v2 == v1))) {
							/* The pointed edge is invalid (tagged as removed, or vert idx mismatch),
							 * and we already know from previous test that a valid one exists, use it (if allowed)! */
							if (do_fixes) {
								int prev_e = ml->e;
								ml->e = POINTER_AS_INT(BLI_edgehash_lookup(edge_hash, v1, v2));
								fix_flag.loops_edge = true;
								PRINT_ERR("\tPoly %u has invalid edge reference (%d, is_removed: %d), fixed using edge %u",
								          sp->index, prev_e, IS_REMOVED_EDGE(me), ml->e);
							}
							else {
								PRINT_ERR("\tPoly %u has invalid edge reference (%u)", sp->index, ml->e);
								sp->invalid = true;
							}
						}
					}
				}

				if (!sp->invalid) {
					/* Needed for checking polys using same verts below. */
					qsort(sp->verts, sp->numverts, sizeof(int), int_cmp);
				}
			}
		}

		/* Second check pass, testing polys using the same verts. */
		qsort(sort_polys, totpoly, sizeof(SortPoly), search_poly_cmp);
		sp = prev_sp = sort_polys;
		sp++;

		for (i = 1; i < totpoly; i++, sp++) {
			int p1_nv = sp->numverts, p2_nv = prev_sp->numverts;
			const int *p1_v = sp->verts, *p2_v = prev_sp->verts;

			if (sp->invalid) {
				/* break, because all known invalid polys have been put at the end by qsort with search_poly_cmp. */
				break;
			}

			/* Test same polys. */
			if ((p1_nv == p2_nv) && (memcmp(p1_v, p2_v, p1_nv * sizeof(*p1_v)) == 0)) {
				if (do_verbose) {
					// TODO: convert list to string
					PRINT_ERR("\tPolys %u and %u use same vertices (%d",
					          prev_sp->index, sp->index, *p1_v);
					for (j = 1; j < p1_nv; j++)
						PRINT_ERR(", %d", p1_v[j]);
					PRINT_ERR("), considering poly %u as invalid.", sp->index);
				}
				else {
					is_valid = false;
				}
				sp->invalid = true;
			}
			else {
				prev_sp = sp;
			}
		}

		/* Third check pass, testing loops used by none or more than one poly. */
		qsort(sort_polys, totpoly, sizeof(SortPoly), search_polyloop_cmp);
		sp = sort_polys;
		prev_sp = NULL;
		prev_end = 0;
		for (i = 0; i < totpoly; i++, sp++) {
			/* Free this now, we don't need it anymore, and avoid us another loop! */
			if (sp->verts)
				MEM_freeN(sp->verts);

			/* Note above prev_sp: in following code, we make sure it is always valid poly (or NULL). */
			if (sp->invalid) {
				if (do_fixes) {
					REMOVE_POLY_TAG((&mpolys[sp->index]));
					/* DO NOT REMOVE ITS LOOPS!!!
					 * As already invalid polys are at the end of the SortPoly list, the loops they
					 * were the only users have already been tagged as "to remove" during previous
					 * iterations, and we don't want to remove some loops that may be used by
					 * another valid poly! */
				}
			}
			/* Test loops users. */
			else {
				/* Unused loops. */
				if (prev_end < sp->loopstart) {
					for (j = prev_end, ml = &mloops[prev_end]; j < sp->loopstart; j++, ml++) {
						PRINT_ERR("\tLoop %u is unused.", j);
						if (do_fixes)
							REMOVE_LOOP_TAG(ml);
					}
					prev_end = sp->loopstart + sp->numverts;
					prev_sp = sp;
				}
				/* Multi-used loops. */
				else if (prev_end > sp->loopstart) {
					PRINT_ERR("\tPolys %u and %u share loops from %d to %d, considering poly %u as invalid.",
					          prev_sp->index, sp->index, sp->loopstart, prev_end, sp->index);
					if (do_fixes) {
						REMOVE_POLY_TAG((&mpolys[sp->index]));
						/* DO NOT REMOVE ITS LOOPS!!!
						 * They might be used by some next, valid poly!
						 * Just not updating prev_end/prev_sp vars is enough to ensure the loops
						 * effectively no more needed will be marked as "to be removed"! */
					}
				}
				else {
					prev_end = sp->loopstart + sp->numverts;
					prev_sp = sp;
				}
			}
		}
		/* We may have some remaining unused loops to get rid of! */
		if (prev_end < totloop) {
			for (j = prev_end, ml = &mloops[prev_end]; j < totloop; j++, ml++) {
				PRINT_ERR("\tLoop %u is unused.", j);
				if (do_fixes)
					REMOVE_LOOP_TAG(ml);
			}
		}

		MEM_freeN(sort_polys);
	}

	BLI_edgehash_free(edge_hash, NULL);

	/* fix deform verts */
	if (dverts) {
		MDeformVert *dv;
		for (i = 0, dv = dverts; i < totvert; i++, dv++) {
			MDeformWeight *dw;

			for (j = 0, dw = dv->dw; j < dv->totweight; j++, dw++) {
				/* note, greater than max defgroups is accounted for in our code, but not < 0 */
				if (!isfinite(dw->weight)) {
					PRINT_ERR("\tVertex deform %u, group %d has weight: %f", i, dw->def_nr, dw->weight);
					if (do_fixes) {
						dw->weight = 0.0f;
						fix_flag.verts_weight = true;
					}
				}
				else if (dw->weight < 0.0f || dw->weight > 1.0f) {
					PRINT_ERR("\tVertex deform %u, group %d has weight: %f", i, dw->def_nr, dw->weight);
					if (do_fixes) {
						CLAMP(dw->weight, 0.0f, 1.0f);
						fix_flag.verts_weight = true;
					}
				}

				if (dw->def_nr < 0) {
					PRINT_ERR("\tVertex deform %u, has invalid group %d", i, dw->def_nr);
					if (do_fixes) {
						defvert_remove_group(dv, dw);
						fix_flag.verts_weight = true;

						if (dv->dw) {
							/* re-allocated, the new values compensate for stepping
							 * within the for loop and may not be valid */
							j--;
							dw = dv->dw + j;

						}
						else { /* all freed */
							break;
						}
					}
				}
			}
		}
	}

#   undef REMOVE_EDGE_TAG
#   undef IS_REMOVED_EDGE
#   undef REMOVE_LOOP_TAG
#   undef REMOVE_POLY_TAG

	if (mesh) {
		if (free_flag.faces) {
			BKE_mesh_strip_loose_faces(mesh);
		}

		if (free_flag.polyloops) {
			BKE_mesh_strip_loose_polysloops(mesh);
		}

		if (free_flag.edges) {
			BKE_mesh_strip_loose_edges(mesh);
		}

		if (recalc_flag.edges) {
			BKE_mesh_calc_edges(mesh, true, false);
		}
	}

	if (mesh && mesh->mselect) {
		MSelect *msel;

		for (i = 0, msel = mesh->mselect; i < mesh->totselect; i++, msel++) {
			int tot_elem = 0;

			if (msel->index < 0) {
				PRINT_ERR("\tMesh select element %u type %d index is negative, "
				          "resetting selection stack.\n", i, msel->type);
				free_flag.mselect = do_fixes;
				break;
			}

			switch (msel->type) {
				case ME_VSEL:
					tot_elem = mesh->totvert;
					break;
				case ME_ESEL:
					tot_elem = mesh->totedge;
					break;
				case ME_FSEL:
					tot_elem = mesh->totface;
					break;
			}

			if (msel->index > tot_elem) {
				PRINT_ERR("\tMesh select element %u type %d index %d is larger than data array size %d, "
				          "resetting selection stack.\n", i, msel->type, msel->index, tot_elem);

				free_flag.mselect = do_fixes;
				break;
			}
		}

		if (free_flag.mselect) {
			MEM_freeN(mesh->mselect);
			mesh->mselect = NULL;
			mesh->totselect = 0;
		}
	}

	PRINT_MSG("%s: finished\n\n", __func__);

	*r_changed = (fix_flag.as_flag || free_flag.as_flag || recalc_flag.as_flag);

	BLI_assert((*r_changed == false) || (do_fixes == true));

	return is_valid;
}

static bool mesh_validate_customdata(
        CustomData *data, CustomDataMask mask, const uint totitems,
        const bool do_verbose, const bool do_fixes,
        bool *r_change)
{
	bool is_valid = true;
	bool has_fixes = false;
	int i = 0;

	PRINT_MSG("%s: Checking %d CD layers...\n", __func__, data->totlayer);

	while (i < data->totlayer) {
		CustomDataLayer *layer = &data->layers[i];
		bool ok = true;

		if (CustomData_layertype_is_singleton(layer->type)) {
			const int layer_tot = CustomData_number_of_layers(data, layer->type);
			if (layer_tot > 1) {
				PRINT_ERR("\tCustomDataLayer type %d is a singleton, found %d in Mesh structure\n",
				          layer->type, layer_tot);
				ok = false;
			}
		}

		if (mask != 0) {
			CustomDataMask layer_typemask = CD_TYPE_AS_MASK(layer->type);
			if ((layer_typemask & mask) == 0) {
				PRINT_ERR("\tCustomDataLayer type %d which isn't in the mask\n",
				          layer->type);
				ok = false;
			}
		}

		if (ok == false) {
			if (do_fixes) {
				CustomData_free_layer(data, layer->type, 0, i);
				has_fixes = true;
			}
		}

		if (ok) {
			if (CustomData_layer_validate(layer, totitems, do_fixes)) {
				PRINT_ERR("\tCustomDataLayer type %d has some invalid data\n", layer->type);
				has_fixes = do_fixes;
			}
			i++;
		}
	}

	PRINT_MSG("%s: Finished (is_valid=%d)\n\n", __func__, (int)!has_fixes);

	*r_change = has_fixes;

	return is_valid;
}

/**
 * \returns is_valid.
 */
bool BKE_mesh_validate_all_customdata(
        CustomData *vdata, const uint totvert,
        CustomData *edata, const uint totedge,
        CustomData *ldata, const uint totloop,
        CustomData *pdata, const uint totpoly,
        const bool check_meshmask,
        const bool do_verbose, const bool do_fixes,
        bool *r_change)
{
	bool is_valid = true;
	bool is_change_v, is_change_e, is_change_l, is_change_p;
	int tot_uvloop, tot_vcolloop;
	CustomDataMask mask = check_meshmask ? CD_MASK_MESH : 0;

	is_valid &= mesh_validate_customdata(vdata, mask, totvert, do_verbose, do_fixes, &is_change_v);
	is_valid &= mesh_validate_customdata(edata, mask, totedge, do_verbose, do_fixes, &is_change_e);
	is_valid &= mesh_validate_customdata(ldata, mask, totloop, do_verbose, do_fixes, &is_change_l);
	is_valid &= mesh_validate_customdata(pdata, mask, totpoly, do_verbose, do_fixes, &is_change_p);

	tot_uvloop = CustomData_number_of_layers(ldata, CD_MLOOPUV);
	tot_vcolloop = CustomData_number_of_layers(ldata, CD_MLOOPCOL);
	if (tot_uvloop > MAX_MTFACE) {
		PRINT_ERR("\tMore UV layers than %d allowed, %d last ones won't be available for render, shaders, etc.\n",
		          MAX_MTFACE, tot_uvloop - MAX_MTFACE);
	}
	if (tot_vcolloop > MAX_MCOL) {
		PRINT_ERR("\tMore VCol layers than %d allowed, %d last ones won't be available for render, shaders, etc.\n",
		          MAX_MCOL, tot_vcolloop - MAX_MCOL);
	}

	/* check indices of clone/stencil */
	if (do_fixes && CustomData_get_clone_layer(ldata, CD_MLOOPUV) >= tot_uvloop) {
		CustomData_set_layer_clone(ldata, CD_MLOOPUV, 0);
		is_change_l = true;
	}
	if (do_fixes && CustomData_get_stencil_layer(ldata, CD_MLOOPUV) >= tot_uvloop) {
		CustomData_set_layer_stencil(ldata, CD_MLOOPUV, 0);
		is_change_l = true;
	}

	*r_change = (is_change_v || is_change_e || is_change_l || is_change_p);

	return is_valid;
}

/**
 * Validates and corrects a Mesh.
 *
 * \returns true if a change is made.
 */
bool BKE_mesh_validate(Mesh *me, const bool do_verbose, const bool cddata_check_mask)
{
	bool is_valid = true;
	bool changed;

	if (do_verbose) {
		CLOG_INFO(&LOG, 0, "MESH: %s", me->id.name + 2);
	}

	is_valid &= BKE_mesh_validate_all_customdata(
	        &me->vdata, me->totvert,
	        &me->edata, me->totedge,
	        &me->ldata, me->totloop,
	        &me->pdata, me->totpoly,
	        cddata_check_mask,
	        do_verbose, true,
	        &changed);

	is_valid &= BKE_mesh_validate_arrays(
	        me,
	        me->mvert, me->totvert,
	        me->medge, me->totedge,
	        me->mface, me->totface,
	        me->mloop, me->totloop,
	        me->mpoly, me->totpoly,
	        me->dvert,
	        do_verbose, true,
	        &changed);

	if (changed) {
		DEG_id_tag_update(&me->id, ID_RECALC_GEOMETRY);
		return true;
	}
	else {
		return false;
	}
}

/**
 * Checks if a Mesh is valid without any modification. This is always verbose.
 *
 * \see  #DM_is_valid to call on derived meshes
 *
 * \returns is_valid.
 */
bool BKE_mesh_is_valid(Mesh *me)
{
	const bool do_verbose = true;
	const bool do_fixes = false;

	bool is_valid = true;
	bool changed = true;

	is_valid &= BKE_mesh_validate_all_customdata(
	        &me->vdata, me->totvert,
	        &me->edata, me->totedge,
	        &me->ldata, me->totloop,
	        &me->pdata, me->totpoly,
	        false,  /* setting mask here isn't useful, gives false positives */
	        do_verbose, do_fixes, &changed);

	is_valid &= BKE_mesh_validate_arrays(
	        me,
	        me->mvert, me->totvert,
	        me->medge, me->totedge,
	        me->mface, me->totface,
	        me->mloop, me->totloop,
	        me->mpoly, me->totpoly,
	        me->dvert,
	        do_verbose, do_fixes,
	        &changed);

	BLI_assert(changed == false);

	return is_valid;
}

/**
 * Check all material indices of polygons are valid, invalid ones are set to 0.
 * \returns is_valid.
 */
bool BKE_mesh_validate_material_indices(Mesh *me)
{
	MPoly *mp;
	const int max_idx = max_ii(0, me->totcol - 1);
	const int totpoly = me->totpoly;
	int i;
	bool is_valid = true;

	for (mp = me->mpoly, i = 0; i < totpoly; i++, mp++) {
		if (mp->mat_nr > max_idx) {
			mp->mat_nr = 0;
			is_valid = false;
		}
	}

	if (!is_valid) {
		DEG_id_tag_update(&me->id, ID_RECALC_GEOMETRY);
		return true;
	}
	else {
		return false;
	}
}

/** \} */


/* -------------------------------------------------------------------- */
/** \name Mesh Stripping (removing invalid data)
 * \{ */

/* We need to keep this for edge creation (for now?), and some old readfile code... */
void BKE_mesh_strip_loose_faces(Mesh *me)
{
	MFace *f;
	int a, b;

	for (a = b = 0, f = me->mface; a < me->totface; a++, f++) {
		if (f->v3) {
			if (a != b) {
				memcpy(&me->mface[b], f, sizeof(me->mface[b]));
				CustomData_copy_data(&me->fdata, &me->fdata, a, b, 1);
			}
			b++;
		}
	}
	if (a != b) {
		CustomData_free_elem(&me->fdata, b, a - b);
		me->totface = b;
	}
}

/* Works on both loops and polys! */
/* Note: It won't try to guess which loops of an invalid poly to remove!
 *       this is the work of the caller, to mark those loops...
 *       See e.g. BKE_mesh_validate_arrays(). */
void BKE_mesh_strip_loose_polysloops(Mesh *me)
{
	MPoly *p;
	MLoop *l;
	int a, b;
	/* New loops idx! */
	int *new_idx = MEM_mallocN(sizeof(int) * me->totloop, __func__);

	for (a = b = 0, p = me->mpoly; a < me->totpoly; a++, p++) {
		bool invalid = false;
		int i = p->loopstart;
		int stop = i + p->totloop;

		if (stop > me->totloop || stop < i) {
			invalid = true;
		}
		else {
			l = &me->mloop[i];
			i = stop - i;
			/* If one of the poly's loops is invalid, the whole poly is invalid! */
			for (; i--; l++) {
				if (l->e == INVALID_LOOP_EDGE_MARKER) {
					invalid = true;
					break;
				}
			}
		}

		if (p->totloop >= 3 && !invalid) {
			if (a != b) {
				memcpy(&me->mpoly[b], p, sizeof(me->mpoly[b]));
				CustomData_copy_data(&me->pdata, &me->pdata, a, b, 1);
			}
			b++;
		}
	}
	if (a != b) {
		CustomData_free_elem(&me->pdata, b, a - b);
		me->totpoly = b;
	}

	/* And now, get rid of invalid loops. */
	for (a = b = 0, l = me->mloop; a < me->totloop; a++, l++) {
		if (l->e != INVALID_LOOP_EDGE_MARKER) {
			if (a != b) {
				memcpy(&me->mloop[b], l, sizeof(me->mloop[b]));
				CustomData_copy_data(&me->ldata, &me->ldata, a, b, 1);
			}
			new_idx[a] = b;
			b++;
		}
		else {
			/* XXX Theoretically, we should be able to not do this, as no remaining poly
			 *     should use any stripped loop. But for security's sake... */
			new_idx[a] = -a;
		}
	}
	if (a != b) {
		CustomData_free_elem(&me->ldata, b, a - b);
		me->totloop = b;
	}

	/* And now, update polys' start loop index. */
	/* Note: At this point, there should never be any poly using a striped loop! */
	for (a = 0, p = me->mpoly; a < me->totpoly; a++, p++) {
		p->loopstart = new_idx[p->loopstart];
	}

	MEM_freeN(new_idx);
}

void BKE_mesh_strip_loose_edges(Mesh *me)
{
	MEdge *e;
	MLoop *l;
	int a, b;
	unsigned int *new_idx = MEM_mallocN(sizeof(int) * me->totedge, __func__);

	for (a = b = 0, e = me->medge; a < me->totedge; a++, e++) {
		if (e->v1 != e->v2) {
			if (a != b) {
				memcpy(&me->medge[b], e, sizeof(me->medge[b]));
				CustomData_copy_data(&me->edata, &me->edata, a, b, 1);
			}
			new_idx[a] = b;
			b++;
		}
		else {
			new_idx[a] = INVALID_LOOP_EDGE_MARKER;
		}
	}
	if (a != b) {
		CustomData_free_elem(&me->edata, b, a - b);
		me->totedge = b;
	}

	/* And now, update loops' edge indices. */
	/* XXX We hope no loop was pointing to a striped edge!
	 *     Else, its e will be set to INVALID_LOOP_EDGE_MARKER :/ */
	for (a = 0, l = me->mloop; a < me->totloop; a++, l++) {
		l->e = new_idx[l->e];
	}

	MEM_freeN(new_idx);
}
/** \} */



/* -------------------------------------------------------------------- */
/** \name Mesh Edge Calculation
 * \{ */

/* make edges in a Mesh, for outside of editmode */

struct EdgeSort {
	unsigned int v1, v2;
	char is_loose, is_draw;
};

/* edges have to be added with lowest index first for sorting */
static void to_edgesort(
        struct EdgeSort *ed,
        unsigned int v1, unsigned int v2,
        char is_loose, short is_draw)
{
	if (v1 < v2) {
		ed->v1 = v1; ed->v2 = v2;
	}
	else {
		ed->v1 = v2; ed->v2 = v1;
	}
	ed->is_loose = is_loose;
	ed->is_draw = is_draw;
}

static int vergedgesort(const void *v1, const void *v2)
{
	const struct EdgeSort *x1 = v1, *x2 = v2;

	if (x1->v1 > x2->v1) return 1;
	else if (x1->v1 < x2->v1) return -1;
	else if (x1->v2 > x2->v2) return 1;
	else if (x1->v2 < x2->v2) return -1;

	return 0;
}


/* Create edges based on known verts and faces,
 * this function is only used when loading very old blend files */

static void mesh_calc_edges_mdata(
        MVert *UNUSED(allvert), MFace *allface, MLoop *allloop,
        MPoly *allpoly, int UNUSED(totvert), int totface, int UNUSED(totloop), int totpoly,
        const bool use_old,
        MEdge **r_medge, int *r_totedge)
{
	MPoly *mpoly;
	MFace *mface;
	MEdge *medge, *med;
	EdgeHash *hash;
	struct EdgeSort *edsort, *ed;
	int a, totedge = 0;
	unsigned int totedge_final = 0;
	unsigned int edge_index;

	/* we put all edges in array, sort them, and detect doubles that way */

	for (a = totface, mface = allface; a > 0; a--, mface++) {
		if (mface->v4) totedge += 4;
		else if (mface->v3) totedge += 3;
		else totedge += 1;
	}

	if (totedge == 0) {
		/* flag that mesh has edges */
		(*r_medge) = MEM_callocN(0, __func__);
		(*r_totedge) = 0;
		return;
	}

	ed = edsort = MEM_mallocN(totedge * sizeof(struct EdgeSort), "EdgeSort");

	for (a = totface, mface = allface; a > 0; a--, mface++) {
		to_edgesort(ed++, mface->v1, mface->v2, !mface->v3, mface->edcode & ME_V1V2);
		if (mface->v4) {
			to_edgesort(ed++, mface->v2, mface->v3, 0, mface->edcode & ME_V2V3);
			to_edgesort(ed++, mface->v3, mface->v4, 0, mface->edcode & ME_V3V4);
			to_edgesort(ed++, mface->v4, mface->v1, 0, mface->edcode & ME_V4V1);
		}
		else if (mface->v3) {
			to_edgesort(ed++, mface->v2, mface->v3, 0, mface->edcode & ME_V2V3);
			to_edgesort(ed++, mface->v3, mface->v1, 0, mface->edcode & ME_V3V1);
		}
	}

	qsort(edsort, totedge, sizeof(struct EdgeSort), vergedgesort);

	/* count final amount */
	for (a = totedge, ed = edsort; a > 1; a--, ed++) {
		/* edge is unique when it differs from next edge, or is last */
		if (ed->v1 != (ed + 1)->v1 || ed->v2 != (ed + 1)->v2) totedge_final++;
	}
	totedge_final++;

	medge = MEM_callocN(sizeof(MEdge) * totedge_final, __func__);

	for (a = totedge, med = medge, ed = edsort; a > 1; a--, ed++) {
		/* edge is unique when it differs from next edge, or is last */
		if (ed->v1 != (ed + 1)->v1 || ed->v2 != (ed + 1)->v2) {
			med->v1 = ed->v1;
			med->v2 = ed->v2;
			if (use_old == false || ed->is_draw) med->flag = ME_EDGEDRAW | ME_EDGERENDER;
			if (ed->is_loose) med->flag |= ME_LOOSEEDGE;

			/* order is swapped so extruding this edge as a surface wont flip face normals
			 * with cyclic curves */
			if (ed->v1 + 1 != ed->v2) {
				SWAP(unsigned int, med->v1, med->v2);
			}
			med++;
		}
		else {
			/* equal edge, we merge the drawflag */
			(ed + 1)->is_draw |= ed->is_draw;
		}
	}
	/* last edge */
	med->v1 = ed->v1;
	med->v2 = ed->v2;
	med->flag = ME_EDGEDRAW;
	if (ed->is_loose) med->flag |= ME_LOOSEEDGE;
	med->flag |= ME_EDGERENDER;

	MEM_freeN(edsort);

	/* set edge members of mloops */
	hash = BLI_edgehash_new_ex(__func__, totedge_final);
	for (edge_index = 0, med = medge; edge_index < totedge_final; edge_index++, med++) {
		BLI_edgehash_insert(hash, med->v1, med->v2, POINTER_FROM_UINT(edge_index));
	}

	mpoly = allpoly;
	for (a = 0; a < totpoly; a++, mpoly++) {
		MLoop *ml, *ml_next;
		int i = mpoly->totloop;

		ml_next = allloop + mpoly->loopstart;  /* first loop */
		ml = &ml_next[i - 1];                  /* last loop */

		while (i-- != 0) {
			ml->e = POINTER_AS_UINT(BLI_edgehash_lookup(hash, ml->v, ml_next->v));
			ml = ml_next;
			ml_next++;
		}
	}

	BLI_edgehash_free(hash, NULL);

	*r_medge = medge;
	*r_totedge = totedge_final;
}

/**
 * If the mesh is from a very old blender version,
 * convert mface->edcode to edge drawflags
 */
void BKE_mesh_calc_edges_legacy(Mesh *me, const bool use_old)
{
	MEdge *medge;
	int totedge = 0;

	mesh_calc_edges_mdata(
	        me->mvert, me->mface, me->mloop, me->mpoly,
	        me->totvert, me->totface, me->totloop, me->totpoly,
	        use_old, &medge, &totedge);

	if (totedge == 0) {
		/* flag that mesh has edges */
		me->medge = medge;
		me->totedge = 0;
		return;
	}

	medge = CustomData_add_layer(&me->edata, CD_MEDGE, CD_ASSIGN, medge, totedge);
	me->medge = medge;
	me->totedge = totedge;

	BKE_mesh_strip_loose_faces(me);
}


/**
 * Calculate edges from polygons
 *
 * \param mesh: The mesh to add edges into
 * \param update: When true create new edges co-exist
 */
void BKE_mesh_calc_edges(Mesh *mesh, bool update, const bool select)
{
	CustomData edata;
	EdgeHashIterator *ehi;
	MPoly *mp;
	MEdge *med, *med_orig;
	EdgeHash *eh;
	unsigned int eh_reserve;
	int i, totedge, totpoly = mesh->totpoly;
	int med_index;
	/* select for newly created meshes which are selected [#25595] */
	const short ed_flag = (ME_EDGEDRAW | ME_EDGERENDER) | (select ? SELECT : 0);

	if (mesh->totedge == 0)
		update = false;

	eh_reserve = max_ii(update ? mesh->totedge : 0, BLI_EDGEHASH_SIZE_GUESS_FROM_POLYS(totpoly));
	eh = BLI_edgehash_new_ex(__func__, eh_reserve);

	if (update) {
		/* assume existing edges are valid
		 * useful when adding more faces and generating edges from them */
		med = mesh->medge;
		for (i = 0; i < mesh->totedge; i++, med++)
			BLI_edgehash_insert(eh, med->v1, med->v2, med);
	}

	/* mesh loops (bmesh only) */
	for (mp = mesh->mpoly, i = 0; i < totpoly; mp++, i++) {
		MLoop *l = &mesh->mloop[mp->loopstart];
		int j, v_prev = (l + (mp->totloop - 1))->v;
		for (j = 0; j < mp->totloop; j++, l++) {
			if (v_prev != l->v) {
				void **val_p;
				if (!BLI_edgehash_ensure_p(eh, v_prev, l->v, &val_p)) {
					*val_p = NULL;
				}
			}
			v_prev = l->v;
		}
	}

	totedge = BLI_edgehash_len(eh);

	/* write new edges into a temporary CustomData */
	CustomData_reset(&edata);
	CustomData_add_layer(&edata, CD_MEDGE, CD_CALLOC, NULL, totedge);

	med = CustomData_get_layer(&edata, CD_MEDGE);
	for (ehi = BLI_edgehashIterator_new(eh), i = 0;
	     BLI_edgehashIterator_isDone(ehi) == false;
	     BLI_edgehashIterator_step(ehi), ++i, ++med)
	{
		if (update && (med_orig = BLI_edgehashIterator_getValue(ehi))) {
			*med = *med_orig; /* copy from the original */
		}
		else {
			BLI_edgehashIterator_getKey(ehi, &med->v1, &med->v2);
			med->flag = ed_flag;
		}

		/* store the new edge index in the hash value */
		BLI_edgehashIterator_setValue(ehi, POINTER_FROM_INT(i));
	}
	BLI_edgehashIterator_free(ehi);

	if (mesh->totpoly) {
		/* second pass, iterate through all loops again and assign
		 * the newly created edges to them. */
		for (mp = mesh->mpoly, i = 0; i < mesh->totpoly; mp++, i++) {
			MLoop *l = &mesh->mloop[mp->loopstart];
			MLoop *l_prev = (l + (mp->totloop - 1));
			int j;
			for (j = 0; j < mp->totloop; j++, l++) {
				/* lookup hashed edge index */
				med_index = POINTER_AS_INT(BLI_edgehash_lookup(eh, l_prev->v, l->v));
				l_prev->e = med_index;
				l_prev = l;
			}
		}
	}

	/* free old CustomData and assign new one */
	CustomData_free(&mesh->edata, mesh->totedge);
	mesh->edata = edata;
	mesh->totedge = totedge;

	mesh->medge = CustomData_get_layer(&mesh->edata, CD_MEDGE);

	BLI_edgehash_free(eh, NULL);
}

void BKE_mesh_calc_edges_loose(Mesh *mesh)
{
	MEdge *med = mesh->medge;
	for (int i = 0; i < mesh->totedge; i++, med++) {
		med->flag |= ME_LOOSEEDGE;
	}
	MLoop *ml = mesh->mloop;
	for (int i = 0; i < mesh->totloop; i++, ml++) {
		mesh->medge[ml->e].flag &= ~ME_LOOSEEDGE;
	}
}

/**
 * Calculate/create edges from tessface data
 *
 * \param mesh: The mesh to add edges into
 */

void BKE_mesh_calc_edges_tessface(Mesh *mesh)
{
	CustomData edgeData;
	EdgeSetIterator *ehi;
	MFace *mf = mesh->mface;
	MEdge *med;
	EdgeSet *eh;
	int i, *index, numEdges, numFaces = mesh->totface;

	eh = BLI_edgeset_new_ex(__func__, BLI_EDGEHASH_SIZE_GUESS_FROM_POLYS(numFaces));

	for (i = 0; i < numFaces; i++, mf++) {
		BLI_edgeset_add(eh, mf->v1, mf->v2);
		BLI_edgeset_add(eh, mf->v2, mf->v3);

		if (mf->v4) {
			BLI_edgeset_add(eh, mf->v3, mf->v4);
			BLI_edgeset_add(eh, mf->v4, mf->v1);
		}
		else {
			BLI_edgeset_add(eh, mf->v3, mf->v1);
		}
	}

	numEdges = BLI_edgeset_len(eh);

	/* write new edges into a temporary CustomData */
	CustomData_reset(&edgeData);
	CustomData_add_layer(&edgeData, CD_MEDGE, CD_CALLOC, NULL, numEdges);
	CustomData_add_layer(&edgeData, CD_ORIGINDEX, CD_CALLOC, NULL, numEdges);

	med = CustomData_get_layer(&edgeData, CD_MEDGE);
	index = CustomData_get_layer(&edgeData, CD_ORIGINDEX);

	for (ehi = BLI_edgesetIterator_new(eh), i = 0;
	     BLI_edgesetIterator_isDone(ehi) == false;
	     BLI_edgesetIterator_step(ehi), i++, med++, index++)
	{
		BLI_edgesetIterator_getKey(ehi, &med->v1, &med->v2);

		med->flag = ME_EDGEDRAW | ME_EDGERENDER;
		*index = ORIGINDEX_NONE;
	}
	BLI_edgesetIterator_free(ehi);

	/* free old CustomData and assign new one */
	CustomData_free(&mesh->edata, mesh->totedge);
	mesh->edata = edgeData;
	mesh->totedge = numEdges;

	mesh->medge = CustomData_get_layer(&mesh->edata, CD_MEDGE);

	BLI_edgeset_free(eh);
}

/** \} */