Refactor: Merge non-functional-change part of 'edit normals' 2017 GSoC.

This merges changes in internals, runtime-only of existing custom
normals code, which make sense as of themselves, and will make diff of
soc branch easier/lighter to review.

In the details, it mostly changes two things:

* Now, smooth fans (aka MLoopNorSpaceArray) can store either loop
indices, or pointers to BMLoop themselves. This makes sense since in
BMesh, it's relatively easy to get index from a BMElement, but nearly
impracticable to go the other way around.

* First change enforces another, now we cannot rely anymore on `loops`
being NULL in MLoopNorSpace to detect single-loop fans, so we instead
store that info in a new flag.

Again, these are expected to be totally non-functional changes.

1 files changed, 3 insertions, 0 deletions

diff --git a/source/blender/bmesh/intern/bmesh_mesh.h b/source/blender/bmesh/intern/bmesh_mesh.h
index 8326e82af00..10f024423aa 100644
--- a/source/blender/bmesh/intern/bmesh_mesh.h
+++ b/source/blender/bmesh/intern/bmesh_mesh.h
@@ -52,6 +52,9 @@ void BM_loops_calc_normal_vcos(
         const bool use_split_normals, const float split_angle, float (*r_lnos)[3],
         struct MLoopNorSpaceArray *r_lnors_spacearr, short (*clnors_data)[2], const int cd_loop_clnors_offset);
 
+bool BM_loop_check_cyclic_smooth_fan(BMLoop *l_curr);
+
+
 void BM_edges_sharp_from_angle_set(BMesh *bm, const float split_angle);
 
 void bmesh_edit_begin(BMesh *bm, const BMOpTypeFlag type_flag);