BMesh: Minor improvement to face-join

Pass in loops instead of edge & faces.
Nearly all callers have the loop-pairs to pass in.

source/blender/bmesh/intern/bmesh_mods.c

@@ -104,7 +104,6 @@ bool BM_vert_dissolve(BMesh *bm, BMVert *v)
  */
 bool BM_disk_dissolve(BMesh *bm, BMVert *v)
 {
-	BMFace *f, *f2;
 	BMEdge *e, *keepedge = NULL, *baseedge = NULL;
 	int len = 0;
 
@@ -141,7 +140,7 @@ bool BM_disk_dissolve(BMesh *bm, BMVert *v)
 			return false;
 		}
 #else
-		if (UNLIKELY(!BM_faces_join_pair(bm, e->l->f, e->l->radial_next->f, e, true))) {
+		if (UNLIKELY(!BM_faces_join_pair(bm, e->l, e->l->radial_next, true))) {
 			return false;
 		}
 		else if (UNLIKELY(!BM_vert_collapse_faces(bm, v->e, v, 1.0, true, false, true))) {
@@ -159,11 +158,10 @@ bool BM_disk_dissolve(BMesh *bm, BMVert *v)
 		}
 
 		/* handle two-valence */
-		f = e->l->f;
-		f2 = e->l->radial_next->f;
-
-		if (f != f2 && !BM_faces_join_pair(bm, f, f2, e, true)) {
-			return false;
+		if (e->l != e->l->radial_next) {
+			if (!BM_faces_join_pair(bm, e->l, e->l->radial_next, true)) {
+				return false;
+			}
 		}
 
 		return true;
@@ -176,9 +174,9 @@ bool BM_disk_dissolve(BMesh *bm, BMVert *v)
 			done = true;
 			e = v->e;
 			do {
-				f = NULL;
+				BMFace *f = NULL;
 				if (BM_edge_is_manifold(e) && (e != baseedge) && (e != keepedge)) {
-					f = BM_faces_join_pair(bm, e->l->f, e->l->radial_next->f, e, true);
+					f = BM_faces_join_pair(bm, e->l, e->l->radial_next, true);
 					/* return if couldn't join faces in manifold
 					 * conditions */
 					/* !disabled for testing why bad things happen */
@@ -204,12 +202,9 @@ bool BM_disk_dissolve(BMesh *bm, BMVert *v)
 		
 		if (e->l) {
 			/* get remaining two faces */
-			f = e->l->f;
-			f2 = e->l->radial_next->f;
-
-			if (f != f2) {
+			if (e->l != e->l->radial_next) {
 				/* join two remaining faces */
-				if (!BM_faces_join_pair(bm, f, f2, e, true)) {
+				if (!BM_faces_join_pair(bm, e->l, e->l->radial_next, true)) {
 					return false;
 				}
 			}
@@ -234,20 +229,16 @@ bool BM_disk_dissolve(BMesh *bm, BMVert *v)
  *
  * \return pointer to the combined face
  */
-BMFace *BM_faces_join_pair(BMesh *bm, BMFace *f_a, BMFace *f_b, BMEdge *e, const bool do_del)
+BMFace *BM_faces_join_pair(BMesh *bm, BMLoop *l_a, BMLoop *l_b, const bool do_del)
 {
-	BMFace *faces[2] = {f_a, f_b};
-
-	BMLoop *l_a = BM_face_edge_share_loop(f_a, e);
-	BMLoop *l_b = BM_face_edge_share_loop(f_b, e);
-
-	BLI_assert(l_a && l_b);
+	BLI_assert((l_a != l_b) && (l_a->e == l_b->e));
 
 	if (l_a->v == l_b->v) {
 		const int cd_loop_mdisp_offset = CustomData_get_offset(&bm->ldata, CD_MDISPS);
-		bmesh_loop_reverse(bm, f_b, cd_loop_mdisp_offset, true);
+		bmesh_loop_reverse(bm, l_b->f, cd_loop_mdisp_offset, true);
 	}
-	
+
+	BMFace *faces[2] = {l_a->f, l_b->f};
 	return BM_faces_join(bm, faces, 2, do_del);
 }
 
@@ -1040,7 +1031,7 @@ BMEdge *BM_edge_rotate(BMesh *bm, BMEdge *e, const bool ccw, const short check_f
 	f_hflag_prev_2 = l2->f->head.hflag;
 
 	/* don't delete the edge, manually remove the edge after so we can copy its attributes */
-	f = BM_faces_join_pair(bm, l1->f, l2->f, e, true);
+	f = BM_faces_join_pair(bm, BM_face_edge_share_loop(l1->f, e), BM_face_edge_share_loop(l2->f, e), true);
 
 	if (f == NULL) {
 		return NULL;

source/blender/bmesh/intern/bmesh_mods.h

@@ -31,7 +31,7 @@ bool BM_vert_dissolve(BMesh *bm, BMVert *v);
 
 bool BM_disk_dissolve(BMesh *bm, BMVert *v);
 
-BMFace *BM_faces_join_pair(BMesh *bm, BMFace *f1, BMFace *f2, BMEdge *e, const bool do_del);
+BMFace *BM_faces_join_pair(BMesh *bm, BMLoop *l_a, BMLoop *l_b, const bool do_del);
 
 
 /** see: bmesh_polygon_edgenet.h for #BM_face_split_edgenet */

source/blender/bmesh/intern/bmesh_queries.c

@@ -926,7 +926,8 @@ bool BM_vert_is_manifold(const BMVert *v)
 
 	/* count edges while looking for non-manifold edges */
 	e_first = e_iter = v->e;
-	l_first = e_iter->l ? e_iter->l : NULL;
+	/* may be null */
+	l_first = e_iter->l;
 	do {
 		/* loose edge or edge shared by more than two faces,
 		 * edges with 1 face user are OK, otherwise we could

source/blender/bmesh/operators/bmo_dissolve.c

@@ -322,12 +322,12 @@ void bmo_dissolve_edges_exec(BMesh *bm, BMOperator *op)
 	}
 
 	BMO_ITER (e, &eiter, op->slots_in, "edges", BM_EDGE) {
-		BMFace *fa, *fb;
-		if (BM_edge_face_pair(e, &fa, &fb)) {
+		BMLoop *l_a, *l_b;
+		if (BM_edge_loop_pair(e, &l_a, &l_b)) {
 			BMFace *f_new;
 
 			/* join faces */
-			f_new = BM_faces_join_pair(bm, fa, fb, e, false);
+			f_new = BM_faces_join_pair(bm, l_a, l_b, false);
 
 			if (f_new) {
 				/* maintain active face */
@@ -437,12 +437,12 @@ void bmo_dissolve_verts_exec(BMesh *bm, BMOperator *op)
 
 		if (!BMO_vert_flag_test(bm, v, VERT_MARK_PAIR)) {
 			BM_ITER_ELEM (e, &itersub, v, BM_EDGES_OF_VERT) {
-				BMFace *fa, *fb;
-				if (BM_edge_face_pair(e, &fa, &fb)) {
+				BMLoop *l_a, *l_b;
+				if (BM_edge_loop_pair(e, &l_a, &l_b)) {
 					BMFace *f_new;
 
 					/* join faces */
-					f_new = BM_faces_join_pair(bm, fa, fb, e, false);
+					f_new = BM_faces_join_pair(bm, l_a, l_b, false);
 
 					/* maintain active face */
 					if (act_face && bm->act_face == NULL) {

source/blender/bmesh/operators/bmo_join_triangles.c

@@ -361,16 +361,16 @@ void bmo_join_triangles_exec(BMesh *bm, BMOperator *op)
 	qsort(jedges, totedge, sizeof(*jedges), BLI_sortutil_cmp_float);
 
 	for (i = 0; i < totedge; i++) {
-		BMFace *f_a, *f_b;
+		BMLoop *l_a, *l_b;
 
 		e = jedges[i].data;
-		f_a = e->l->f;
-		f_b = e->l->radial_next->f;
+		l_a = e->l;
+		l_b = e->l->radial_next;
 
 		/* check if another edge already claimed this face */
-		if ((f_a->len == 3) && (f_b->len == 3)) {
+		if ((l_a->f->len == 3) && (l_b->f->len == 3)) {
 			BMFace *f_new;
-			f_new = BM_faces_join_pair(bm, f_a, f_b, e, true);
+			f_new = BM_faces_join_pair(bm, l_a, l_b, true);
 			if (f_new) {
 				BMO_face_flag_enable(bm, f_new, FACE_OUT);
 			}

source/blender/bmesh/operators/bmo_triangulate.c

@@ -253,10 +253,7 @@ void bmo_triangle_fill_exec(BMesh *bm, BMOperator *op)
 			if (BMO_edge_flag_test(bm, e, ELE_NEW)) {
 				/* in rare cases the edges face will have already been removed from the edge */
 				if (LIKELY(e->l)) {
-					BMFace *f_new = BM_faces_join_pair(
-					        bm, e->l->f,
-					        e->l->radial_next->f, e,
-					        false); /* join faces */
+					BMFace *f_new = BM_faces_join_pair(bm, e->l, e->l->radial_next, false);
 					if (f_new) {
 						BMO_face_flag_enable(bm, f_new, ELE_NEW);
 						BM_edge_kill(bm, e);

source/blender/bmesh/tools/bmesh_decimate_dissolve.c

@@ -322,9 +322,7 @@ void BM_mesh_decimate_dissolve_ex(
 			i = BM_elem_index_get(e);
 
 			if (BM_edge_is_manifold(e)) {
-				f_new = BM_faces_join_pair(bm, e->l->f,
-				                           e->l->radial_next->f, e,
-				                           false); /* join faces */
+				f_new = BM_faces_join_pair(bm, e->l, e->l->radial_next, false);
 
 				if (f_new) {
 					BMLoop *l_first, *l_iter;