fix [#35555] Collada: export destroys mesh in some cases

add arguments to calculate normals when converting to bmesh:
  BM_mesh_bm_from_me, DM_to_bmesh

This gives some speedup to undo (which didnt need to re-calculate vertex normals), and array modifier which doesnt need to calculate face normals at all

3 files changed, 9 insertions, 3 deletions

diff --git a/source/blender/bmesh/intern/bmesh_mesh_conv.c b/source/blender/bmesh/intern/bmesh_mesh_conv.c
index 6d1db98f32e..9d330075a3a 100644
--- a/source/blender/bmesh/intern/bmesh_mesh_conv.c
+++ b/source/blender/bmesh/intern/bmesh_mesh_conv.c
@@ -185,7 +185,8 @@ static BMFace *bm_face_create_from_mpoly(MPoly *mp, MLoop *ml,
  *
  * \warning This function doesn't calculate face normals.
  */
-void BM_mesh_bm_from_me(BMesh *bm, Mesh *me, bool set_key, int act_key_nr)
+void BM_mesh_bm_from_me(BMesh *bm, Mesh *me,
+                        const bool calc_face_normal, const bool set_key, int act_key_nr)
 {
 	MVert *mvert;
 	MEdge *medge;
@@ -397,6 +398,10 @@ void BM_mesh_bm_from_me(BMesh *bm, Mesh *me, bool set_key, int act_key_nr)
 
 		/* Copy Custom Data */
 		CustomData_to_bmesh_block(&me->pdata, &bm->pdata, i, &f->head.data, true);
+
+		if (calc_face_normal) {
+			BM_face_normal_update(f);
+		}
 	}
 
 	bm->elem_index_dirty &= ~BM_FACE; /* added in order, clear dirty flag */
diff --git a/source/blender/bmesh/intern/bmesh_mesh_conv.h b/source/blender/bmesh/intern/bmesh_mesh_conv.h
index 7fe4b8fe58b..754ae8bcad4 100644
--- a/source/blender/bmesh/intern/bmesh_mesh_conv.h
+++ b/source/blender/bmesh/intern/bmesh_mesh_conv.h
@@ -38,7 +38,8 @@ void BM_mesh_cd_flag_ensure(BMesh *bm, struct Mesh *mesh, const char cd_flag);
 void BM_mesh_cd_flag_apply(BMesh *bm, const char cd_flag);
 char BM_mesh_cd_flag_from_bmesh(BMesh *bm);
 
-void BM_mesh_bm_from_me(BMesh *bm, struct Mesh *me, bool set_key, int act_key_nr);
+void BM_mesh_bm_from_me(BMesh *bm, struct Mesh *me,
+                        const bool calc_face_normal, const bool set_key, int act_key_nr);
 void BM_mesh_bm_to_me(BMesh *bm, struct Mesh *me, bool do_tessface);
 
 #endif /* __BMESH_MESH_CONV_H__ */
diff --git a/source/blender/bmesh/operators/bmo_mesh_conv.c b/source/blender/bmesh/operators/bmo_mesh_conv.c
index a75d0353079..d124aaaf80e 100644
--- a/source/blender/bmesh/operators/bmo_mesh_conv.c
+++ b/source/blender/bmesh/operators/bmo_mesh_conv.c
@@ -45,7 +45,7 @@ void bmo_mesh_to_bmesh_exec(BMesh *bm, BMOperator *op)
 	Mesh *me     = BMO_slot_ptr_get(op->slots_in,  "mesh");
 	bool set_key = BMO_slot_bool_get(op->slots_in, "use_shapekey");
 
-	BM_mesh_bm_from_me(bm, me, set_key, ob->shapenr);
+	BM_mesh_bm_from_me(bm, me, false, set_key, ob->shapenr);
 
 	if (me->key && ob->shapenr > me->key->totkey) {
 		ob->shapenr = me->key->totkey - 1;