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, 3 insertions, 0 deletions

diff --git a/source/blender/editors/include/ED_mesh.h b/source/blender/editors/include/ED_mesh.h
index b76c35c7d7a..0e2be5eb568 100644
--- a/source/blender/editors/include/ED_mesh.h
+++ b/source/blender/editors/include/ED_mesh.h
@@ -36,6 +36,7 @@ struct BMFace;
 struct BMLoop;
 struct BMVert;
 struct BMesh;
+struct BMeshNormalsUpdate_Params;
 struct Base;
 struct Depsgraph;
 struct ID;
@@ -76,6 +77,8 @@ struct BMFace *EDBM_verts_mirror_get_face(struct BMEditMesh *em, struct BMFace *
 void EDBM_verts_mirror_cache_clear(struct BMEditMesh *em, struct BMVert *v);
 void EDBM_verts_mirror_cache_end(struct BMEditMesh *em);
 
+void EDBM_mesh_normals_update_ex(struct BMEditMesh *em,
+                                 const struct BMeshNormalsUpdate_Params *params);
 void EDBM_mesh_normals_update(struct BMEditMesh *em);
 void EDBM_mesh_clear(struct BMEditMesh *em);