BMesh: support face-normal calculation in normal & looptri functions

Support calculating face normals when tessellating. When this is done
before updating vertex normals it gives ~20% performance improvement.

Now vertex normal calculation only needs to perform a single pass on the
mesh vertices when called after tessellation.

Extended versions of normal & looptri update functions have been added:

- BM_mesh_calc_tessellation_ex
- BM_mesh_normals_update_ex

Most callers don't need to be aware of this detail by using:

- BKE_editmesh_looptri_and_normals_calc
- BKE_editmesh_looptri_and_normals_calc_with_partial

- EDBM_update also takes advantage of this,
  where calling EDBM_update with calc_looptri & calc_normals
  enabled uses the faster normal updating logic.

1 files changed, 1 insertions, 3 deletions

diff --git a/source/blender/editors/object/object_edit.c b/source/blender/editors/object/object_edit.c
index 5be572baec5..c8923bb55c1 100644
--- a/source/blender/editors/object/object_edit.c
+++ b/source/blender/editors/object/object_edit.c
@@ -794,9 +794,7 @@ bool ED_object_editmode_enter_ex(Main *bmain, Scene *scene, Object *ob, int flag
 
     BMEditMesh *em = BKE_editmesh_from_object(ob);
     if (LIKELY(em)) {
-      /* order doesn't matter */
-      EDBM_mesh_normals_update(em);
-      BKE_editmesh_looptri_calc(em);
+      BKE_editmesh_looptri_and_normals_calc(em);
     }
 
     WM_main_add_notifier(NC_SCENE | ND_MODE | NS_EDITMODE_MESH, NULL);