Improvements to bmesh edge rotate

On a user level, edge rotate now works better with multiple edges selected, it wont make zero area faces or rotate edges into existing ones.

With a single edge selected - rotate is less strict and will allow ugly resulting faces but still checks on duplicate edges.

API:
* BM_edge_rotate now takes a flag, to optionally...
** check for existing edge
** splice edge (rotate and merge)
** check for degenerate resulting faces (overlapping geometry, zero area)
** beauty - only rotate to a better fit.
... this allows it to still be used as a low level API function since all checks can be skipped.

* BM_edge_rotate() now works a bit different, it find the new edge rotation before joining the faces - exposed by BM_edge_rotate_calc().

* Added api call bmesh_radial_faceloop_find_vert() - Radial Find a Vertex Loop in Face

1 files changed, 24 insertions, 5 deletions

diff --git a/source/blender/bmesh/intern/bmesh_structure.c b/source/blender/bmesh/intern/bmesh_structure.c
index ad6a8a615e3..abce7780e79 100644
--- a/source/blender/bmesh/intern/bmesh_structure.c
+++ b/source/blender/bmesh/intern/bmesh_structure.c
@@ -201,15 +201,13 @@ void bmesh_disk_edge_remove(BMEdge *e, BMVert *v)
 	dl1->next = dl1->prev = NULL;
 }
 
-/*
- *			bmesh_disk_edge_next
+/**
+ * \brief Next Disk Edge
  *
  *	Find the next edge in a disk cycle
  *
- *  Returns -
- *	Pointer to the next edge in the disk cycle for the vertex v.
+ *	\return Pointer to the next edge in the disk cycle for the vertex v.
  */
-
 BMEdge *bmesh_disk_edge_next(BMEdge *e, BMVert *v)
 {
 	if (v == e->v1)
@@ -453,6 +451,27 @@ BMLoop *bmesh_radial_faceloop_find_next(BMLoop *l, BMVert *v)
 	return l;
 }
 
+/* NOTE: this function has not been used or tested - so take care but it should work ok,
+ * I wrote it for some tool that ended up not using it, however this seems like a reasonable
+ * thing to be able to find the loop between a vertex and a face so keeping - campbell */
+/**
+ * \brief Radial Find a Vertex Loop in Face
+ *
+ * Finds the loop used which uses \a v in face loop \a l
+ */
+BMLoop *bmesh_radial_faceloop_find_vert(BMFace *f, BMVert *v) /* name is a bit awkward */
+{
+	BMLoop *l_iter, *l_first;
+	if (v->e && (l_iter = l_first = v->e->l)) {
+		do {
+			if (l_iter->v == v && l_iter->f == f) {
+				return l_iter;
+			}
+		} while ((l_iter = l_iter->radial_next) != l_first);
+	}
+	return NULL;
+}
+
 int bmesh_radial_length(BMLoop *l)
 {
 	BMLoop *l_iter = l;