Mesh: Start refactor of lazy face corner normals

This needs to wait until 4.0

@@ -59,0 +170,4 @@
+void do_versions_after_linking_400(FileData * /*fd*/, Main *bmain)
+{
+  if (!MAIN_VERSION_FILE_ATLEAST(bmain, 400, 14)) {
+    version_mesh_objects_replace_auto_smooth(*bmain);

@@ -2078,0 +2197,4 @@
+      BLI_addtail(&object->modifiers, md);
+    }
+
+    md->settings.properties = bke::idprop::create_group("Nodes Modifier Settings").release();

@@ -2819,3 +2819,2 @@
                 layout.operator("object.shade_smooth")
-                layout.operator("object.shade_smooth", text="Shade Auto Smooth").use_auto_smooth = True
-                layout.operator("object.shade_flat", text="Shade Flat")
+                layout.operator("object.shade_smooth_by_angle")

@@ -502,0 +470,4 @@
+      if (domain == ATTR_DOMAIN_FACE) {
+        mesh_final->face_normals();
+      }
+      else if (domain == ATTR_DOMAIN_FACE) {

@@ -783,0 +849,4 @@
+  }
+}
+
+static void build_edge_to_loop_map(const OffsetIndices<int> faces,

@@ -425,3 +441,1 @@
-  ME_AUTOSMOOTH = 1 << 5,
-  ME_FLAG_UNUSED_6 = 1 << 6, /* cleared */
-  ME_FLAG_UNUSED_7 = 1 << 7, /* cleared */
+  ME_AUTOSMOOTH = 1 << 5,        /* deprecated */

@@ -499,3 +469,1 @@
-     * (i.e. even if auto-smooth is disabled). */
-    if (CustomData_has_layer(&mesh_final->loop_data, CD_NORMAL)) {
-      CustomData_free_layers(&mesh_final->loop_data, CD_NORMAL, mesh_final->totloop);
+      /* Eager normal calculation can potentially be faster than deferring the to drawing code. */

@@ -2075,0 +2110,4 @@
+  bNode *store_node = nodeAddNode(nullptr, node_tree, "GeometryNodeStoreNamedAttribute");
+  store_node->locx = 40.0f;
+  store_node->locy = 40.0f;
+  static_cast<NodeGeometryStoreNamedAttribute *>(store_node->storage)->data_type = CD_PROP_BOOL;

@@ -342,1 +417,4 @@
+  }
 
+  BM_mesh_elem_table_ensure(bm, BM_FACE);
+  const VArrayImpl_For_SharpFace sharp_faces({bm->ftable, bm->totface});

@@ -362,0 +366,4 @@
+   * face corner normals, since there is a 2-4x performance cost increase for each more complex
+   * domain.
+   */
+  int normal_domain_all_info() const;

@@ -2249,3 +2214,2 @@
   RNA_def_property_range(prop, -1.0f, 1.0f);
-  RNA_def_property_float_funcs(
-      prop, "rna_MeshLoop_normal_get", "rna_MeshLoop_normal_set", nullptr);
+  RNA_def_property_float_funcs(prop, "rna_MeshLoop_normal_get", nullptr, nullptr);

@@ -337,1 +340,3 @@
-void mesh_render_data_update_normals(MeshRenderData &mr, const eMRDataType data_flag)
+static bool bm_edge_is_sharp(const BMEdge *const &edge)
+{
+  return BM_elem_flag_test(edge, BM_ELEM_SMOOTH);