BMesh: avoid extra calls per faces-of-vert iterator

- `bmesh_radial_faceloop_find_first` & `bmesh_disk_faceedge_find_first`
  can be replaced with a single call to a new function:
  `bmesh_disk_faceloop_find_first`

- `bmesh_disk_faceedge_find_first` called `bmesh_radial_facevert_check`
  which isn't needed, since either the current or next loop in the
  cycle is attached to the edge we're looking for.

3 files changed, 24 insertions, 8 deletions

diff --git a/source/blender/bmesh/intern/bmesh_iterators.c b/source/blender/bmesh/intern/bmesh_iterators.c
index 961b10d848a..96154f051f9 100644
--- a/source/blender/bmesh/intern/bmesh_iterators.c
+++ b/source/blender/bmesh/intern/bmesh_iterators.c
@@ -485,9 +485,9 @@ void  bmiter__face_of_vert_begin(struct BMIter__face_of_vert *iter)
 {
 	((BMIter *)iter)->count = bmesh_disk_facevert_count(iter->vdata);
 	if (((BMIter *)iter)->count) {
-		iter->e_first = bmesh_disk_faceedge_find_first(iter->vdata->e, iter->vdata);
+		iter->l_first = bmesh_disk_faceloop_find_first(iter->vdata->e, iter->vdata);
+		iter->e_first = iter->l_first->e;
 		iter->e_next = iter->e_first;
-		iter->l_first = bmesh_radial_faceloop_find_first(iter->e_first->l, iter->vdata);
 		iter->l_next = iter->l_first;
 	}
 	else {
@@ -526,9 +526,9 @@ void  bmiter__loop_of_vert_begin(struct BMIter__loop_of_vert *iter)
 {
 	((BMIter *)iter)->count = bmesh_disk_facevert_count(iter->vdata);
 	if (((BMIter *)iter)->count) {
-		iter->e_first = bmesh_disk_faceedge_find_first(iter->vdata->e, iter->vdata);
+		iter->l_first = bmesh_disk_faceloop_find_first(iter->vdata->e, iter->vdata);
+		iter->e_first = iter->l_first->e;
 		iter->e_next = iter->e_first;
-		iter->l_first = bmesh_radial_faceloop_find_first(iter->e_first->l, iter->vdata);
 		iter->l_next = iter->l_first;
 	}
 	else {
diff --git a/source/blender/bmesh/intern/bmesh_structure.c b/source/blender/bmesh/intern/bmesh_structure.c
index 6052de421dd..8e484841568 100644
--- a/source/blender/bmesh/intern/bmesh_structure.c
+++ b/source/blender/bmesh/intern/bmesh_structure.c
@@ -338,13 +338,28 @@ int bmesh_disk_facevert_count_ex(const BMVert *v, const int count_max)
  */
 BMEdge *bmesh_disk_faceedge_find_first(const BMEdge *e, const BMVert *v)
 {
-	const BMEdge *e_find = e;
+	const BMEdge *e_iter = e;
 	do {
-		if (e_find->l && bmesh_radial_facevert_check(e_find->l, v)) {
-			return (BMEdge *)e_find;
+		if (e_iter->l != NULL) {
+			return (BMEdge *)((e_iter->l->v == v) ? e_iter : e_iter->l->next->e);
 		}
-	} while ((e_find = bmesh_disk_edge_next(e_find, v)) != e);
+	} while ((e_iter = bmesh_disk_edge_next(e_iter, v)) != e);
+	return NULL;
+}
 
+/**
+ * Special case for BM_LOOPS_OF_VERT & BM_FACES_OF_VERT, avoids 2x calls.
+ *
+ * The returned BMLoop.e matches the result of #bmesh_disk_faceedge_find_first
+ */
+BMLoop *bmesh_disk_faceloop_find_first(const BMEdge *e, const BMVert *v)
+{
+	const BMEdge *e_iter = e;
+	do {
+		if (e_iter->l != NULL) {
+			return (e_iter->l->v == v) ? e_iter->l : e_iter->l->next;
+		}
+	} while ((e_iter = bmesh_disk_edge_next(e_iter, v)) != e);
 	return NULL;
 }
 
diff --git a/source/blender/bmesh/intern/bmesh_structure.h b/source/blender/bmesh/intern/bmesh_structure.h
index 679e7a269b3..0efb25da37c 100644
--- a/source/blender/bmesh/intern/bmesh_structure.h
+++ b/source/blender/bmesh/intern/bmesh_structure.h
@@ -52,6 +52,7 @@ BLI_INLINE BMEdge *bmesh_disk_edge_prev(const BMEdge *e, const BMVert *v) ATTR_W
 int     bmesh_disk_facevert_count_ex(const BMVert *v, const int count_max) ATTR_WARN_UNUSED_RESULT ATTR_NONNULL();
 int     bmesh_disk_facevert_count(const BMVert *v) ATTR_WARN_UNUSED_RESULT ATTR_NONNULL();
 BMEdge *bmesh_disk_faceedge_find_first(const BMEdge *e, const BMVert *v) ATTR_WARN_UNUSED_RESULT ATTR_NONNULL();
+BMLoop *bmesh_disk_faceloop_find_first(const BMEdge *e, const BMVert *v) ATTR_WARN_UNUSED_RESULT ATTR_NONNULL();
 BMEdge *bmesh_disk_faceedge_find_next(const BMEdge *e, const BMVert *v) ATTR_WARN_UNUSED_RESULT ATTR_NONNULL();
 
 /* RADIAL CYCLE MANAGMENT */