mesh_validate code for bmesh (i.e. polys/loops).

Everything seems to work well (many tests making random changes over various meshes went good), but the code is a bit complex and hard to follow, due to the various possibilities of invalid poly/loop combinations… Code also makes more operations than previous tri/quad faces version (hence is a bit slower), but I don’t think we can do otherwise, it’s just the price for bmesh flexibility. ;)

Note: added the py script I used to make the tests, under source/tests/...

1 files changed, 369 insertions, 235 deletions

diff --git a/source/blender/blenkernel/intern/mesh_validate.c b/source/blender/blenkernel/intern/mesh_validate.c
index fbd7a5fb47b..0a10184c730 100644
--- a/source/blender/blenkernel/intern/mesh_validate.c
+++ b/source/blender/blenkernel/intern/mesh_validate.c
@@ -33,111 +33,91 @@
 
 #include "DNA_mesh_types.h"
 #include "DNA_meshdata_types.h"
+#include "DNA_object_types.h"
 
 #include "BLO_sys_types.h"
 
-#include "BLI_utildefines.h"
 #include "BLI_edgehash.h"
 #include "BLI_math_base.h"
+#include "BLI_utildefines.h"
 
+#include "BKE_deform.h"
+#include "BKE_depsgraph.h"
 #include "BKE_DerivedMesh.h"
+#include "BKE_mesh.h"
 
 #include "MEM_guardedalloc.h"
 
-#include "BKE_mesh.h"
-#include "BKE_deform.h"
-
 #define SELECT 1
 
-typedef union {
-	uint32_t verts[2];
-	int64_t edval;
-} EdgeUUID;
-
-typedef struct SortFace {
-//	unsigned int	v[4];
-	EdgeUUID		es[4];
-	unsigned int	index;
-} SortFace;
-
-static void edge_store_assign(uint32_t verts[2],  const uint32_t v1, const uint32_t v2)
+/* 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;
+	int invalid; /* Poly index. */
+} SortPoly;
+
+/* TODO check there is not some standard define of this somewhere! */
+static int int_cmp(const void *v1, const void *v2)
 {
-	if(v1 < v2) {
-		verts[0]= v1;
-		verts[1]= v2;
-	}
-	else {
-		verts[0]= v2;
-		verts[1]= v1;
-	}
+	return *(int*)v1 > *(int*)v2 ? 1 : *(int*)v1 < *(int*)v2 ? -1 : 0;
 }
 
-static void edge_store_from_mface_quad(EdgeUUID es[4], MFace *mf)
+static int search_poly_cmp(const void *v1, const void *v2)
 {
-	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);
+	const SortPoly *sp1 = v1, *sp2 = v2;
+	const int max_idx = sp1->numverts > sp2->numverts ? sp2->numverts : sp1->numverts;
+	int idx = 0;
+
+	/* 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 first non-egal verts (remember verts of valid polys are sorted). */
+	while (idx < max_idx && sp1->verts[idx] == sp2->verts[idx])
+		idx++;
+	return sp1->verts[idx] > sp2->verts[idx] ? 1 : sp1->verts[idx] < sp2->verts[idx] ? -1 :
+	       sp1->numverts > sp2->numverts ? 1 : sp1->numverts < sp2->numverts ? -1 : 0;
 }
 
-static void edge_store_from_mface_tri(EdgeUUID es[4], MFace *mf)
+static int search_polyloop_cmp(const void *v1, const void *v2)
 {
-	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;
-	else										  return 0;
+	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;
 }
 
 #define PRINT if(do_verbose) printf
 
-int BKE_mesh_validate_arrays( Mesh *me,
-                              MVert *mverts, unsigned int totvert,
-                              MEdge *medges, unsigned int totedge,
-                              MFace *mfaces, unsigned int totface,
-                              MDeformVert *dverts, /* assume totvert length */
-                              const short do_verbose, const short do_fixes)
+int BKE_mesh_validate_arrays(Mesh *mesh,
+                             MVert *mverts, unsigned int totvert,
+                             MEdge *medges, unsigned int totedge,
+                             MLoop *mloops, unsigned int totloop,
+                             MPoly *mpolys, unsigned int totpoly,
+                             MDeformVert *dverts, /* assume totvert length */
+                             const short do_verbose, const short do_fixes)
 {
-#	define REMOVE_EDGE_TAG(_med) { _med->v2= _med->v1; do_edge_free= 1; }
-#	define REMOVE_FACE_TAG(_mf) { _mf->v3=0; do_face_free= 1; }
+#	define REMOVE_EDGE_TAG(_me) { _me->v2 = _me->v1; do_edge_free = TRUE; }
+#	define IS_REMOVED_EDGE(_me) (_me->v2 == _me->v1)
+
+#	define REMOVE_LOOP_TAG(_ml) { _ml->e = INVALID_LOOP_EDGE_MARKER; do_polyloop_free = TRUE; }
+#	define REMOVE_POLY_TAG(_mp) { _mp->totloop *= -1; do_polyloop_free = TRUE; }
 
-//	MVert *mv;
-	MEdge *med;
-	MFace *mf;
-	MFace *mf_prev;
-	MVert *mvert= mverts;
-	unsigned int i;
+	MVert *mv = mverts;
+	MEdge *me;
+	MLoop *ml;
+	MPoly *mp;
+	unsigned int i, j;
+	int *v;
 
-	short do_face_free= FALSE;
 	short do_edge_free= FALSE;
+	short do_polyloop_free= FALSE; /* This regroups loops and polys! */
 
 	short verts_fixed= FALSE;
 	short vert_weights_fixed= FALSE;
@@ -146,180 +126,347 @@ int BKE_mesh_validate_arrays( Mesh *me,
 
 	EdgeHash *edge_hash = BLI_edgehash_new();
 
-	SortFace *sort_faces= MEM_callocN(sizeof(SortFace) * totface, "search faces");
-	SortFace *sf;
-	SortFace *sf_prev;
-	unsigned int totsortface= 0;
-
-	BLI_assert(!(do_fixes && me == NULL));
+	BLI_assert(!(do_fixes && mesh == NULL));
 
-	PRINT("%s: verts(%u), edges(%u), faces(%u)\n", __func__, totvert, totedge, totface);
+	PRINT("%s: verts(%u), edges(%u), loops(%u), polygons(%u)\n",
+	      __func__, totvert, totedge, totloop, totpoly);
 
-	if(totedge == 0 && totface != 0) {
-		PRINT("    locical error, %u faces and 0 edges\n", totface);
-		do_edge_recalc= TRUE;
+	if(totedge == 0 && totpoly != 0) {
+		PRINT("    logical error, %u polygons and 0 edges\n", totpoly);
+		do_edge_recalc = do_fixes;
 	}
 
-	for(i=1; i<totvert; i++, mvert++) {
+	for(i=1; i<totvert; i++, mv++) {
 		int j;
 		int fix_normal= TRUE;
 
 		for(j=0; j<3; j++) {
-			if(!finite(mvert->co[j])) {
+			if(!finite(mv->co[j])) {
 				PRINT("    vertex %u: has invalid coordinate\n", i);
 
 				if (do_fixes) {
-					zero_v3(mvert->co);
+					zero_v3(mv->co);
 
 					verts_fixed= TRUE;
 				}
 			}
 
-			if(mvert->no[j]!=0)
+			if(mv->no[j]!=0)
 				fix_normal= FALSE;
 		}
 
 		if(fix_normal) {
 			PRINT("    vertex %u: has zero normal, assuming Z-up normal\n", i);
 			if (do_fixes) {
-				mvert->no[2]= SHRT_MAX;
+				mv->no[2]= SHRT_MAX;
 				verts_fixed= TRUE;
 			}
 		}
 	}
 
-	for(i=0, med= medges; i<totedge; i++, med++) {
+	for(i=0, me= medges; i<totedge; i++, me++) {
 		int remove= FALSE;
-		if(med->v1 == med->v2) {
-			PRINT("    edge %u: has matching verts, both %u\n", i, med->v1);
+		if(me->v1 == me->v2) {
+			PRINT("    edge %u: has matching verts, both %u\n", i, me->v1);
 			remove= do_fixes;
 		}
-		if(med->v1 >= totvert) {
-			PRINT("    edge %u: v1 index out of range, %u\n", i, med->v1);
+		if(me->v1 >= totvert) {
+			PRINT("    edge %u: v1 index out of range, %u\n", i, me->v1);
 			remove= do_fixes;
 		}
-		if(med->v2 >= totvert) {
-			PRINT("    edge %u: v2 index out of range, %u\n", i, med->v2);
+		if(me->v2 >= totvert) {
+			PRINT("    edge %u: v2 index out of range, %u\n", i, me->v2);
 			remove= do_fixes;
 		}
 
-		if(BLI_edgehash_haskey(edge_hash, med->v1, med->v2)) {
-			PRINT("    edge %u: is a duplicate of, %d\n", i, GET_INT_FROM_POINTER(BLI_edgehash_lookup(edge_hash, med->v1, med->v2)));
+		if(BLI_edgehash_haskey(edge_hash, me->v1, me->v2)) {
+			PRINT("    edge %u: is a duplicate of %d\n", i,
+			      GET_INT_FROM_POINTER(BLI_edgehash_lookup(edge_hash, me->v1, me->v2)));
 			remove= do_fixes;
 		}
 
 		if(remove == FALSE) {
-			BLI_edgehash_insert(edge_hash, med->v1, med->v2, SET_INT_IN_POINTER(i));
+			BLI_edgehash_insert(edge_hash, me->v1, me->v2, SET_INT_IN_POINTER(i));
 		}
 		else {
-			REMOVE_EDGE_TAG(med);
+			REMOVE_EDGE_TAG(me);
 		}
 	}
 
-	for(i=0, mf=mfaces, sf=sort_faces; i<totface; i++, mf++) {
-		int remove= FALSE;
-		int fidx;
-		unsigned int fv[4];
-
-		fidx = mf->v4 ? 3:2;
-		do {
-			fv[fidx]= *(&(mf->v1) + fidx);
-			if(fv[fidx] >= totvert) {
-				PRINT("    face %u: 'v%d' index out of range, %u\n", i, fidx + 1, fv[fidx]);
-				remove= do_fixes;
+	/* Checking loops and polys is a bit tricky, as they are quite intricated...
+	 *
+	 * 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/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("    poly %u is invalid (loopstart: %u, totloop: %u)\n", sp->index, mp->loopstart, mp->totloop);
+				sp->invalid = TRUE;
 			}
-		} while (fidx--);
-
-		if(remove == FALSE) {
-			if(mf->v4) {
-				if(mf->v1 == mf->v2) { PRINT("    face %u: verts invalid, v1/v2 both %u\n", i, mf->v1); remove= do_fixes; }
-				if(mf->v1 == mf->v3) { PRINT("    face %u: verts invalid, v1/v3 both %u\n", i, mf->v1); remove= do_fixes; }
-				if(mf->v1 == mf->v4) { PRINT("    face %u: verts invalid, v1/v4 both %u\n", i, mf->v1); remove= do_fixes; }
-
-				if(mf->v2 == mf->v3) { PRINT("    face %u: verts invalid, v2/v3 both %u\n", i, mf->v2); remove= do_fixes; }
-				if(mf->v2 == mf->v4) { PRINT("    face %u: verts invalid, v2/v4 both %u\n", i, mf->v2); remove= do_fixes; }
-
-				if(mf->v3 == mf->v4) { PRINT("    face %u: verts invalid, v3/v4 both %u\n", i, mf->v3); remove= do_fixes; }
+			else if (mp->loopstart + mp->totloop > totloop) {
+				/* Invalid loop data. */
+				PRINT("    poly %u uses loops out of range (loopstart: %u, loopend: %u, max nbr of loops: %u)\n",
+				      sp->index, mp->loopstart, mp->loopstart + mp->totloop - 1, totloop - 1);
+				sp->invalid = TRUE;
 			}
 			else {
-				if(mf->v1 == mf->v2) { PRINT("    faceT %u: verts invalid, v1/v2 both %u\n", i, mf->v1); remove= do_fixes; }
-				if(mf->v1 == mf->v3) { PRINT("    faceT %u: verts invalid, v1/v3 both %u\n", i, mf->v1); remove= do_fixes; }
-
-				if(mf->v2 == mf->v3) { PRINT("    faceT %u: verts invalid, v2/v3 both %u\n", i, mf->v2); remove= do_fixes; }
-			}
+				/* 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;
+
+				/* 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("    loop %u has invalid vert reference (%u)\n", sp->loopstart + j, ml->v);
+						sp->invalid = TRUE;
+					}
+					*v = ml->v;
+				}
 
-			if(remove == FALSE) {
-				if(totedge) {
-					if(mf->v4) {
-						if(!BLI_edgehash_haskey(edge_hash, mf->v1, mf->v2)) { PRINT("    face %u: edge v1/v2 (%u,%u) is missing egde data\n", i, mf->v1, mf->v2); do_edge_recalc= TRUE; }
-						if(!BLI_edgehash_haskey(edge_hash, mf->v2, mf->v3)) { PRINT("    face %u: edge v2/v3 (%u,%u) is missing egde data\n", i, mf->v2, mf->v3); do_edge_recalc= TRUE; }
-						if(!BLI_edgehash_haskey(edge_hash, mf->v3, mf->v4)) { PRINT("    face %u: edge v3/v4 (%u,%u) is missing egde data\n", i, mf->v3, mf->v4); do_edge_recalc= TRUE; }
-						if(!BLI_edgehash_haskey(edge_hash, mf->v4, mf->v1)) { PRINT("    face %u: edge v4/v1 (%u,%u) is missing egde data\n", i, mf->v4, mf->v1); do_edge_recalc= TRUE; }
+				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("    poly %u needs missing edge (%u, %u)\n", sp->index, v1, v2);
+						if (do_fixes)
+							do_edge_recalc = 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 = GET_INT_FROM_POINTER(BLI_edgehash_lookup(edge_hash, v1, v2));
+							PRINT("    loop %u has invalid edge reference (%u), fixed using edge %u\n",
+							      sp->loopstart + j, prev_e, ml->e);
+						}
+						else {
+							PRINT("    loop %u has invalid edge reference (%u)\n", sp->loopstart + j, ml->e);
+							sp->invalid = TRUE;
+						}
 					}
 					else {
-						if(!BLI_edgehash_haskey(edge_hash, mf->v1, mf->v2)) { PRINT("    face %u: edge v1/v2 (%u,%u) is missing egde data\n", i, mf->v1, mf->v2); do_edge_recalc= TRUE; }
-						if(!BLI_edgehash_haskey(edge_hash, mf->v2, mf->v3)) { PRINT("    face %u: edge v2/v3 (%u,%u) is missing egde data\n", i, mf->v2, mf->v3); do_edge_recalc= TRUE; }
-						if(!BLI_edgehash_haskey(edge_hash, mf->v3, mf->v1)) { PRINT("    face %u: edge v3/v1 (%u,%u) is missing egde data\n", i, mf->v3, mf->v1); do_edge_recalc= TRUE; }
+						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 = GET_INT_FROM_POINTER(BLI_edgehash_lookup(edge_hash, v1, v2));
+								PRINT("    poly %u has invalid edge reference (%u), fixed using edge %u\n",
+									  sp->index, prev_e, ml->e);
+							}
+							else {
+								PRINT("    poly %u has invalid edge reference (%u)\n", sp->index, ml->e);
+								sp->invalid = TRUE;
+							}
+						}
 					}
 				}
 
-				sf->index = i;
-
-				if(mf->v4) {
-					edge_store_from_mface_quad(sf->es, mf);
+				/* Now check that that poly does not use a same vertex more than once! */
+				if (!sp->invalid) {
+					int *prev_v = v = sp->verts;
+					j = sp->numverts;
+
+					qsort(sp->verts, j, sizeof(int), int_cmp);
+
+					for (j--, v++; j; j--, v++) {
+						if (*v != *prev_v) {
+							int dlt = v - prev_v;
+							if (dlt > 1) {
+								PRINT("    poly %u is invalid, it multi-uses vertex %u (%u times)\n",
+								      sp->index, *prev_v, dlt);
+								sp->invalid = TRUE;
+							}
+							prev_v = v;
+						}
+					}
+					if (v - prev_v > 1) { /* Don’t forget final verts! */
+						PRINT("    poly %u is invalid, it multi-uses vertex %u (%u times)\n",
+						      sp->index, *prev_v, (int)(v - prev_v));
+						sp->invalid = TRUE;
+					}
+				}
+			
+			}
+		}
 
-					qsort(sf->es, 4, sizeof(int64_t), int64_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;
+			int *p1_v = sp->verts, *p2_v = prev_sp->verts;
+			short p1_sub = TRUE, p2_sub = TRUE;
+			if (sp->invalid)
+				break;
+			/* Test same polys. */
+#if 0
+			/* NOTE: This performs a sub-set test. */
+			/* XXX This (and the sort of verts list) is better than systematic
+			 *     search of all verts of one list into the other if lists have
+			 *     a fair amount of elements.
+			 *     Not sure however it's worth it in this case?
+			 *     But as we also need sorted vert list to check verts multi-used
+			 *     (in first pass of checks)... */
+			/* XXX If we consider only "equal" polys (i.e. using exactly same set of verts)
+			 *     as invalid, better to replace this by a simple memory cmp... */
+			while ((p1_nv && p2_nv) && (p1_sub || p2_sub)) {
+				if (*p1_v < *p2_v) {
+					if (p1_sub)
+						p1_sub = FALSE;
+					p1_nv--;
+					p1_v++;
+				}
+				else if (*p2_v < *p1_v) {
+					if (p2_sub)
+						p2_sub = FALSE;
+					p2_nv--;
+					p2_v++;
 				}
 				else {
-					edge_store_from_mface_tri(sf->es, mf);
-					qsort(sf->es, 3, sizeof(int64_t), int64_cmp);
+					/* Equality, both next verts. */
+					p1_nv--;
+					p2_nv--;
+					p1_v++;
+					p2_v++;
 				}
-
-				totsortface++;
-				sf++;
+			}
+			if (p1_nv && p1_sub)
+				p1_sub = FALSE;
+			else if (p2_nv && p2_sub)
+				p2_sub = FALSE;
+
+			if (p1_sub && p2_sub) {
+				PRINT("    polys %u and %u use same vertices, considering poly %u as invalid.\n",
+				      prev_sp->index, sp->index, sp->index);
+				sp->invalid = TRUE;
+			}
+			/* XXX In fact, these might be valid? :/ */
+			else if (p1_sub) {
+				PRINT("    %u is a sub-poly of %u, considering it as invalid.\n", sp->index, prev_sp->index);
+				sp->invalid = TRUE;
+			}
+			else if (p2_sub) {
+				PRINT("    %u is a sub-poly of %u, considering it as invalid.\n", prev_sp->index, sp->index);
+				prev_sp->invalid = TRUE;
+				prev_sp = sp; /* sp is new reference poly. */
+			}
+#else
+			if (0) {
+				p1_sub += 0;
+				p2_sub += 0;
+			}
+			if((p1_nv == p2_nv) && (memcmp(p1_v, p2_v, p1_nv * sizeof(*p1_v)) == 0)) {
+				if (do_verbose) {
+					PRINT("    polys %u and %u use same vertices (%u",
+					      prev_sp->index, sp->index, *p1_v);
+					for (j = 1; j < p1_nv; j++)
+						PRINT(", %u", p1_v[j]);
+					PRINT("), considering poly %u as invalid.\n", sp->index);
+				}
+				sp->invalid = TRUE;
+			}
+#endif
+			else {
+				prev_sp = sp;
 			}
 		}
-		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++) {
-		int 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("    face %u & %u: are duplicates (%u,%u,%u,%u) (%u,%u,%u,%u)\n", 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);
+		/* 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("    loop %u is unused.\n", 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("    polys %u and %u share loops from %u to %u, considering poly %u as invalid.\n",
+					      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 {
-					PRINT("    face %u & %u: are duplicates (%u,%u,%u) (%u,%u,%u)\n", sf->index, sf_prev->index, mf->v1, mf->v2, mf->v3, mf_prev->v1, mf_prev->v2, mf_prev->v3);
+					prev_end = sp->loopstart + sp->numverts;
+					prev_sp = sp;
 				}
 			}
-
-			remove= do_fixes;
 		}
-		else {
-			sf_prev= sf;
+		/* 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("    loop %u is unused.\n", j);
+				if (do_fixes)
+					REMOVE_LOOP_TAG(ml);
+			}
 		}
 
-		if(remove) {
-			REMOVE_FACE_TAG(mf);
-		}
+		MEM_freeN(sort_polys);
 	}
 
 	BLI_edgehash_free(edge_hash, NULL);
-	MEM_freeN(sort_faces);
-
 
 	/* fix deform verts */
 	if (dverts) {
@@ -366,27 +513,28 @@ int BKE_mesh_validate_arrays( Mesh *me,
 		}
 	}
 
-
 	PRINT("BKE_mesh_validate: finished\n\n");
 
-#	 undef REMOVE_EDGE_TAG
-#	 undef REMOVE_FACE_TAG
+#	undef REMOVE_EDGE_TAG
+#	undef IS_REMOVED_EDGE
+#	undef REMOVE_LOOP_TAG
+#	undef REMOVE_POLY_TAG
 
-	if(me) {
-		if(do_face_free) {
-			mesh_strip_loose_faces(me);
+	if(mesh) {
+		if(do_polyloop_free) {
+			mesh_strip_loose_polysloops(mesh);
 		}
 
 		if (do_edge_free) {
-			mesh_strip_loose_edges(me);
+			mesh_strip_loose_edges(mesh);
 		}
 
-		if(do_fixes && do_edge_recalc) {
-			BKE_mesh_calc_edges(me, TRUE);
+		if(do_edge_recalc) {
+			BKE_mesh_calc_edges(mesh, TRUE);
 		}
 	}
 
-	return (verts_fixed || vert_weights_fixed || do_face_free || do_edge_free || do_edge_recalc);
+	return (verts_fixed || vert_weights_fixed || do_polyloop_free || do_edge_free || do_edge_recalc);
 }
 
 static int mesh_validate_customdata(CustomData *data, short do_verbose, const short do_fixes)
@@ -417,16 +565,18 @@ static int mesh_validate_customdata(CustomData *data, short do_verbose, const sh
 
 #undef PRINT
 
-static int BKE_mesh_validate_all_customdata(CustomData *vdata, CustomData *edata, CustomData *fdata,
+static int BKE_mesh_validate_all_customdata(CustomData *vdata, CustomData *edata,
+                                            CustomData *ldata, CustomData *pdata,
                                             short do_verbose, const short do_fixes)
 {
-	int vfixed= 0, efixed= 0, ffixed= 0;
+	int vfixed= 0, efixed= 0, lfixed = 0, pfixed = 0;
 
 	vfixed= mesh_validate_customdata(vdata, do_verbose, do_fixes);
 	efixed= mesh_validate_customdata(edata, do_verbose, do_fixes);
-	ffixed= mesh_validate_customdata(fdata, do_verbose, do_fixes);
+	lfixed= mesh_validate_customdata(ldata, do_verbose, do_fixes);
+	pfixed= mesh_validate_customdata(pdata, do_verbose, do_fixes);
 
-	return vfixed || efixed || ffixed;
+	return vfixed || efixed || lfixed || pfixed;
 }
 
 int BKE_mesh_validate(Mesh *me, int do_verbose)
@@ -437,35 +587,41 @@ int BKE_mesh_validate(Mesh *me, int do_verbose)
 		printf("MESH: %s\n", me->id.name+2);
 	}
 
-	layers_fixed= BKE_mesh_validate_all_customdata(&me->vdata, &me->edata, &me->fdata, do_verbose, TRUE);
+	layers_fixed= BKE_mesh_validate_all_customdata(&me->vdata, &me->edata, &me->ldata, &me->pdata, do_verbose, TRUE);
 	arrays_fixed= 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);
 
-	return layers_fixed || arrays_fixed;
+	if (layers_fixed || arrays_fixed) {
+		DAG_id_tag_update(&me->id, OB_RECALC_DATA);
+		return TRUE;
+	}
+	return FALSE;
 }
 
 int BKE_mesh_validate_dm(DerivedMesh *dm)
 {
 	return BKE_mesh_validate_arrays(NULL,
-                                    dm->getVertArray(dm), dm->getNumVerts(dm),
-                                    dm->getEdgeArray(dm), dm->getNumEdges(dm),
-                                    dm->getTessFaceArray(dm), dm->getNumTessFaces(dm),
-                                    dm->getVertDataArray(dm, CD_MDEFORMVERT),
-                                    TRUE, FALSE);
+	                                dm->getVertArray(dm), dm->getNumVerts(dm),
+	                                dm->getEdgeArray(dm), dm->getNumEdges(dm),
+	                                dm->getLoopArray(dm), dm->getNumLoops(dm),
+	                                dm->getPolyArray(dm), dm->getNumPolys(dm),
+	                                dm->getVertDataArray(dm, CD_MDEFORMVERT),
+	                                TRUE, FALSE);
 }
 
 void BKE_mesh_calc_edges(Mesh *mesh, int update)
 {
 	CustomData edata;
 	EdgeHashIterator *ehi;
-	MFace *mf = mesh->mface;
+	MPoly *mp = mesh->mpoly;
 	MEdge *med, *med_orig;
 	EdgeHash *eh = BLI_edgehash_new();
-	int i, totedge, totface = mesh->totface;
+	int i, totedge, totpoly = mesh->totpoly;
 	int med_index;
 
 	if(mesh->totedge==0)
@@ -479,37 +635,15 @@ void BKE_mesh_calc_edges(Mesh *mesh, int update)
 			BLI_edgehash_insert(eh, med->v1, med->v2, med);
 	}
 
-	if(mesh->totpoly) {
-		/* mesh loops (bmesh only) */
-		MPoly *mp= mesh->mpoly;
-		for(i=0; i < mesh->totpoly; i++, mp++) {
-			MLoop *l= &mesh->mloop[mp->loopstart];
-			int j, l_prev= (l + (mp->totloop-1))->v;
-			for (j=0; j < mp->totloop; j++, l++) {
-				if (!BLI_edgehash_haskey(eh, l_prev, l->v)) {
-					BLI_edgehash_insert(eh, l_prev, l->v, NULL);
-				}
-				l_prev= l->v;
-			}
-		}
-	}
-	else {
-		/* regular faces (note, we could remove this for bmesh - campbell) */
-		for (i = 0; i < totface; i++, mf++) {
-			if (!BLI_edgehash_haskey(eh, mf->v1, mf->v2))
-				BLI_edgehash_insert(eh, mf->v1, mf->v2, NULL);
-			if (!BLI_edgehash_haskey(eh, mf->v2, mf->v3))
-				BLI_edgehash_insert(eh, mf->v2, mf->v3, NULL);
-
-			if (mf->v4) {
-				if (!BLI_edgehash_haskey(eh, mf->v3, mf->v4))
-					BLI_edgehash_insert(eh, mf->v3, mf->v4, NULL);
-				if (!BLI_edgehash_haskey(eh, mf->v4, mf->v1))
-					BLI_edgehash_insert(eh, mf->v4, mf->v1, NULL);
-			} else {
-				if (!BLI_edgehash_haskey(eh, mf->v3, mf->v1))
-					BLI_edgehash_insert(eh, mf->v3, mf->v1, NULL);
+	/* mesh loops (bmesh only) */
+	for(i=0; i < totpoly; i++, mp++) {
+		MLoop *l= &mesh->mloop[mp->loopstart];
+		int j, l_prev= (l + (mp->totloop-1))->v;
+		for (j=0; j < mp->totloop; j++, l++) {
+			if (!BLI_edgehash_haskey(eh, l_prev, l->v)) {
+				BLI_edgehash_insert(eh, l_prev, l->v, NULL);
 			}
+			l_prev= l->v;
 		}
 	}