Normal UI: for all ops needing autosmooth on, enable it if needed.

Now Normal menu operations and rotate normals (r n) do not need
manual enabling of autosmooth first.
See T64324 for discussion of Normal UI changes.

source/blender/blenkernel/BKE_editmesh.h

@@ -90,6 +90,7 @@ void BKE_editmesh_color_free(BMEditMesh *em);
 void BKE_editmesh_color_ensure(BMEditMesh *em, const char htype);
 float (*BKE_editmesh_vertexCos_get_orco(BMEditMesh *em, int *r_numVerts))[3];
 void BKE_editmesh_lnorspace_update(BMEditMesh *em);
+void BKE_editmesh_ensure_autosmooth(BMEditMesh *em);
 
 /* editderivedmesh.c */
 /* should really be defined in editmesh.c, but they use 'EditDerivedBMesh' */

source/blender/blenkernel/intern/editmesh.c

@@ -248,3 +248,13 @@ void BKE_editmesh_lnorspace_update(BMEditMesh *em)
 
   BM_lnorspace_update(bm);
 }
+
+/* If autosmooth not already set, set it */
+void BKE_editmesh_ensure_autosmooth(BMEditMesh *em)
+{
+  Mesh *me = em->ob->data;
+  if (!(me->flag & ME_AUTOSMOOTH)) {
+    me->flag |= ME_AUTOSMOOTH;
+    BKE_editmesh_lnorspace_update (em);
+  }
+}

source/blender/editors/mesh/editmesh_tools.c

@@ -7687,6 +7687,7 @@ static int point_normals_init(bContext *C, wmOperator *op, const wmEvent *UNUSED
   BMEditMesh *em = BKE_editmesh_from_object(obedit);
   BMesh *bm = em->bm;
 
+  BKE_editmesh_ensure_autosmooth(em);
   BKE_editmesh_lnorspace_update(em);
   BMLoopNorEditDataArray *lnors_ed_arr = BM_loop_normal_editdata_array_init(bm);
 
@@ -8076,7 +8077,7 @@ void MESH_OT_point_normals(struct wmOperatorType *ot)
   ot->exec = edbm_point_normals_exec;
   ot->invoke = edbm_point_normals_invoke;
   ot->modal = edbm_point_normals_modal;
-  ot->poll = ED_operator_editmesh_auto_smooth;
+  ot->poll = ED_operator_editmesh;
   ot->ui = edbm_point_normals_ui;
   ot->cancel = point_normals_free;
 
@@ -8242,6 +8243,7 @@ static int normals_split_merge(bContext *C, const bool do_merge)
   BMEdge *e;
   BMIter eiter;
 
+  BKE_editmesh_ensure_autosmooth(em);
   BKE_editmesh_lnorspace_update(em);
 
   BMLoopNorEditDataArray *lnors_ed_arr = do_merge ? BM_loop_normal_editdata_array_init(bm) : NULL;
@@ -8287,7 +8289,7 @@ void MESH_OT_merge_normals(struct wmOperatorType *ot)
 
   /* api callbacks */
   ot->exec = edbm_merge_normals_exec;
-  ot->poll = ED_operator_editmesh_auto_smooth;
+  ot->poll = ED_operator_editmesh;
 
   /* flags */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
@@ -8307,7 +8309,7 @@ void MESH_OT_split_normals(struct wmOperatorType *ot)
 
   /* api callbacks */
   ot->exec = edbm_split_normals_exec;
-  ot->poll = ED_operator_editmesh_auto_smooth;
+  ot->poll = ED_operator_editmesh;
 
   /* flags */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
@@ -8345,6 +8347,7 @@ static int edbm_average_normals_exec(bContext *C, wmOperator *op)
   BMLoop *l, *l_curr, *l_first;
   BMIter fiter;
 
+  BKE_editmesh_ensure_autosmooth(em);
   bm->spacearr_dirty |= BM_SPACEARR_DIRTY_ALL;
   BKE_editmesh_lnorspace_update(em);
 
@@ -8505,7 +8508,7 @@ void MESH_OT_average_normals(struct wmOperatorType *ot)
 
   /* api callbacks */
   ot->exec = edbm_average_normals_exec;
-  ot->poll = ED_operator_editmesh_auto_smooth;
+  ot->poll = ED_operator_editmesh;
   ot->ui = edbm_average_normals_ui;
 
   /* flags */
@@ -8568,6 +8571,7 @@ static int edbm_normals_tools_exec(bContext *C, wmOperator *op)
   const int mode = RNA_enum_get(op->ptr, "mode");
   const bool absolute = RNA_boolean_get(op->ptr, "absolute");
 
+  BKE_editmesh_ensure_autosmooth(em);
   BKE_editmesh_lnorspace_update(em);
   BMLoopNorEditDataArray *lnors_ed_arr = BM_loop_normal_editdata_array_init(bm);
   BMLoopNorEditData *lnor_ed = lnors_ed_arr->lnor_editdata;
@@ -8724,7 +8728,7 @@ void MESH_OT_normals_tools(struct wmOperatorType *ot)
 
   /* api callbacks */
   ot->exec = edbm_normals_tools_exec;
-  ot->poll = ED_operator_editmesh_auto_smooth;
+  ot->poll = ED_operator_editmesh;
   ot->ui = edbm_normals_tools_ui;
 
   /* flags */
@@ -8764,6 +8768,7 @@ static int edbm_set_normals_from_faces_exec(bContext *C, wmOperator *op)
 
     const bool keep_sharp = RNA_boolean_get(op->ptr, "keep_sharp");
 
+    BKE_editmesh_ensure_autosmooth(em);
     BKE_editmesh_lnorspace_update(em);
 
     float(*vnors)[3] = MEM_callocN(sizeof(*vnors) * bm->totvert, __func__);
@@ -8842,7 +8847,7 @@ void MESH_OT_set_normals_from_faces(struct wmOperatorType *ot)
 
   /* api callbacks */
   ot->exec = edbm_set_normals_from_faces_exec;
-  ot->poll = ED_operator_editmesh_auto_smooth;
+  ot->poll = ED_operator_editmesh;
 
   /* flags */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
@@ -8859,6 +8864,7 @@ static int edbm_smoothen_normals_exec(bContext *C, wmOperator *op)
   BMLoop *l;
   BMIter fiter, liter;
 
+  BKE_editmesh_ensure_autosmooth(em);
   BKE_editmesh_lnorspace_update(em);
   BMLoopNorEditDataArray *lnors_ed_arr = BM_loop_normal_editdata_array_init(bm);
 
@@ -8934,7 +8940,7 @@ void MESH_OT_smoothen_normals(struct wmOperatorType *ot)
 
   /* api callbacks */
   ot->exec = edbm_smoothen_normals_exec;
-  ot->poll = ED_operator_editmesh_auto_smooth;
+  ot->poll = ED_operator_editmesh;
 
   /* flags */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
@@ -9017,7 +9023,7 @@ void MESH_OT_mod_weighted_strength(struct wmOperatorType *ot)
 
   /* api callbacks */
   ot->exec = edbm_mod_weighted_strength_exec;
-  ot->poll = ED_operator_editmesh_auto_smooth;
+  ot->poll = ED_operator_editmesh;
 
   /* flags */
   ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;

source/blender/editors/transform/transform.c

@@ -4835,6 +4835,7 @@ static void initNormalRotation(TransInfo *t)
     BMEditMesh *em = BKE_editmesh_from_object(tc->obedit);
     BMesh *bm = em->bm;
 
+    BKE_editmesh_ensure_autosmooth(em);
     BKE_editmesh_lnorspace_update(em);
 
     storeCustomLNorValue(tc, bm);

source/blender/editors/transform/transform_ops.c

@@ -1170,7 +1170,7 @@ static void TRANSFORM_OT_rotate_normal(struct wmOperatorType *ot)
   ot->exec = transform_exec;
   ot->modal = transform_modal;
   ot->cancel = transform_cancel;
-  ot->poll = ED_operator_editmesh_auto_smooth;
+  ot->poll = ED_operator_editmesh;
 
   RNA_def_float_rotation(
       ot->srna, "value", 0, NULL, -FLT_MAX, FLT_MAX, "Angle", "", -M_PI * 2, M_PI * 2);