1 files changed, 26 insertions, 0 deletions
diff --git a/source/blender/bmesh/intern/bmesh_core.c b/source/blender/bmesh/intern/bmesh_core.c
index 34e11f5c9f9..8441a6ec75f 100644
--- a/source/blender/bmesh/intern/bmesh_core.c
+++ b/source/blender/bmesh/intern/bmesh_core.c
@@ -1278,6 +1278,7 @@ BMFace *bmesh_sfme(BMesh *bm, BMFace *f, BMVert *v1, BMVert *v2,
 	}
 
 	if (!l_v1 || !l_v2) {
+		BLI_assert(0);
 		return NULL;
 	}
 
@@ -2278,3 +2279,28 @@ BMVert *bmesh_urmv(BMesh *bm, BMFace *f_sep, BMVert *v_sep)
 	BMLoop *l = BM_face_vert_share_loop(f_sep, v_sep);
 	return bmesh_urmv_loop(bm, l);
 }
+
+/**
+ * Avoid calling this where possible,
+ * low level function so both face pointers remain intact but point to swapped data.
+ * \note must be from the same bmesh.
+ */
+void bmesh_face_swap_data(BMesh *bm, BMFace *f_a, BMFace *f_b)
+{
+	BMLoop *l_iter, *l_first;
+
+	BLI_assert(f_a != f_b);
+
+	l_iter = l_first = BM_FACE_FIRST_LOOP(f_a);
+	do {
+		l_iter->f = f_b;
+	} while ((l_iter = l_iter->next) != l_first);
+
+	l_iter = l_first = BM_FACE_FIRST_LOOP(f_b);
+	do {
+		l_iter->f = f_a;
+	} while ((l_iter = l_iter->next) != l_first);
+
+	SWAP(BMFace, (*f_a), (*f_b));
+	bm->elem_index_dirty |= BM_FACE;
+}