Mesh: Avoid unnecessary normal calculation and dirty tags

This is mostly a cleanup to avoid hardcoding the eager calculation of
normals it isn't necessary, by reducing calls to `BKE_mesh_calc_normals`
and by removing calls to `BKE_mesh_normals_tag_dirty` when the mesh
is newly created and already has dirty normals anyway. This reduces
boilerplate code and makes the "dirty by default" state more clear.
Any regressions from this commit should be easy to fix, though the
lazy calculation is solid enough that none are expected.

56 files changed, 28 insertions, 120 deletions

diff --git a/source/blender/blenkernel/intern/cloth.c b/source/blender/blenkernel/intern/cloth.c
index f7454a02de6..0d6a0c045a5 100644
--- a/source/blender/blenkernel/intern/cloth.c
+++ b/source/blender/blenkernel/intern/cloth.c
@@ -1171,6 +1171,7 @@ static Mesh *cloth_make_rest_mesh(ClothModifierData *clmd, Mesh *mesh)
   for (unsigned i = 0; i < mesh->totvert; i++, verts++) {
     copy_v3_v3(mvert[i].co, verts->xrest);
   }
+  BKE_mesh_normals_tag_dirty(new_mesh);
 
   return new_mesh;
 }
@@ -1507,7 +1508,6 @@ static bool cloth_build_springs(ClothModifierData *clmd, Mesh *mesh)
     if (clmd->sim_parms->shapekey_rest &&
         !(clmd->sim_parms->flags & CLOTH_SIMSETTINGS_FLAG_DYNAMIC_BASEMESH)) {
       tmp_mesh = cloth_make_rest_mesh(clmd, mesh);
-      BKE_mesh_calc_normals(tmp_mesh);
     }
 
     EdgeSet *existing_vert_pairs = BLI_edgeset_new("cloth_sewing_edges_graph");
diff --git a/source/blender/blenkernel/intern/curve_to_mesh_convert.cc b/source/blender/blenkernel/intern/curve_to_mesh_convert.cc
index c48d155f5ce..d7fd8f7a2b6 100644
--- a/source/blender/blenkernel/intern/curve_to_mesh_convert.cc
+++ b/source/blender/blenkernel/intern/curve_to_mesh_convert.cc
@@ -649,7 +649,6 @@ Mesh *curve_to_mesh_sweep(const CurvesGeometry &main,
       offsets.vert.last(), offsets.edge.last(), 0, offsets.loop.last(), offsets.poly.last());
   mesh->flag |= ME_AUTOSMOOTH;
   mesh->smoothresh = DEG2RADF(180.0f);
-  BKE_mesh_normals_tag_dirty(mesh);
   MutableSpan<MVert> verts(mesh->mvert, mesh->totvert);
   MutableSpan<MEdge> edges(mesh->medge, mesh->totedge);
   MutableSpan<MLoop> loops(mesh->mloop, mesh->totloop);
diff --git a/source/blender/blenkernel/intern/displist.cc b/source/blender/blenkernel/intern/displist.cc
index 8c1161d6ff6..5caed6d6219 100644
--- a/source/blender/blenkernel/intern/displist.cc
+++ b/source/blender/blenkernel/intern/displist.cc
@@ -887,17 +887,11 @@ static GeometrySet curve_calc_modifiers_post(Depsgraph *depsgraph,
     if (mti->type == eModifierTypeType_OnlyDeform) {
       int totvert;
       float(*vertex_coords)[3] = BKE_mesh_vert_coords_alloc(mesh, &totvert);
-      if (mti->dependsOnNormals != nullptr && mti->dependsOnNormals(md)) {
-        BKE_mesh_vertex_normals_ensure(mesh);
-      }
       mti->deformVerts(md, &mectx_deform, mesh, vertex_coords, totvert);
       BKE_mesh_vert_coords_apply(mesh, vertex_coords);
       MEM_freeN(vertex_coords);
     }
     else {
-      if (mti->dependsOnNormals != nullptr && mti->dependsOnNormals(md)) {
-        BKE_mesh_vertex_normals_ensure(mesh);
-      }
       Mesh *output_mesh = mti->modifyMesh(md, &mectx_apply, mesh);
       if (mesh != output_mesh) {
         geometry_set.replace_mesh(output_mesh);
diff --git a/source/blender/blenkernel/intern/dynamicpaint.c b/source/blender/blenkernel/intern/dynamicpaint.c
index b85b2b3157c..01fd53d1ea2 100644
--- a/source/blender/blenkernel/intern/dynamicpaint.c
+++ b/source/blender/blenkernel/intern/dynamicpaint.c
@@ -1899,7 +1899,6 @@ static Mesh *dynamicPaint_Modifier_apply(DynamicPaintModifierData *pmd, Object *
       pmd->type == MOD_DYNAMICPAINT_TYPE_CANVAS) {
 
     DynamicPaintSurface *surface;
-    bool update_normals = false;
 
     /* loop through surfaces */
     for (surface = pmd->canvas->surfaces.first; surface; surface = surface->next) {
@@ -2018,21 +2017,17 @@ static Mesh *dynamicPaint_Modifier_apply(DynamicPaintModifierData *pmd, Object *
             settings.use_threading = (sData->total_points > 1000);
             BLI_task_parallel_range(
                 0, sData->total_points, &data, dynamic_paint_apply_surface_wave_cb, &settings);
-            update_normals = true;
+            BKE_mesh_normals_tag_dirty(mesh);
           }
 
           /* displace */
           if (surface->type == MOD_DPAINT_SURFACE_T_DISPLACE) {
             dynamicPaint_applySurfaceDisplace(surface, result);
-            update_normals = true;
+            BKE_mesh_normals_tag_dirty(mesh);
           }
         }
       }
     }
-
-    if (update_normals) {
-      BKE_mesh_normals_tag_dirty(result);
-    }
   }
   /* make a copy of mesh to use as brush data */
   else if (pmd->brush && pmd->type == MOD_DYNAMICPAINT_TYPE_BRUSH) {
diff --git a/source/blender/blenkernel/intern/fluid.c b/source/blender/blenkernel/intern/fluid.c
index efb33294efd..5de13fbdbed 100644
--- a/source/blender/blenkernel/intern/fluid.c
+++ b/source/blender/blenkernel/intern/fluid.c
@@ -3537,7 +3537,6 @@ static Mesh *create_smoke_geometry(FluidDomainSettings *fds, Mesh *orgmesh, Obje
   }
 
   BKE_mesh_calc_edges(result, false, false);
-  BKE_mesh_normals_tag_dirty(result);
   return result;
 }
 
diff --git a/source/blender/blenkernel/intern/mesh.cc b/source/blender/blenkernel/intern/mesh.cc
index 25d97d0bd3c..7f005fda6a5 100644
--- a/source/blender/blenkernel/intern/mesh.cc
+++ b/source/blender/blenkernel/intern/mesh.cc
@@ -1112,6 +1112,9 @@ Mesh *BKE_mesh_new_nomain_from_template_ex(const Mesh *me_src,
   mesh_ensure_cdlayers_primary(me_dst, do_tessface);
   BKE_mesh_update_customdata_pointers(me_dst, false);
 
+  /* Expect that normals aren't copied at all, since the destination mesh is new. */
+  BLI_assert(BKE_mesh_vertex_normals_are_dirty(me_dst));
+
   return me_dst;
 }
 
@@ -1688,6 +1691,7 @@ void BKE_mesh_transform(Mesh *me, const float mat[4][4], bool do_keys)
       mul_m3_v3(m3, *lnors);
     }
   }
+  BKE_mesh_normals_tag_dirty(me);
 }
 
 void BKE_mesh_translate(Mesh *me, const float offset[3], const bool do_keys)
diff --git a/source/blender/blenkernel/intern/mesh_boolean_convert.cc b/source/blender/blenkernel/intern/mesh_boolean_convert.cc
index eee1d3b9eec..3fcacb31b24 100644
--- a/source/blender/blenkernel/intern/mesh_boolean_convert.cc
+++ b/source/blender/blenkernel/intern/mesh_boolean_convert.cc
@@ -782,7 +782,6 @@ static Mesh *imesh_to_mesh(IMesh *im, MeshesToIMeshInfo &mim)
     }
   }
 
-  BKE_mesh_calc_normals(result);
   if (dbg_level > 0) {
     BKE_mesh_validate(result, true, true);
   }
diff --git a/source/blender/blenkernel/intern/mesh_convert.cc b/source/blender/blenkernel/intern/mesh_convert.cc
index ff953ef5b46..a289d208684 100644
--- a/source/blender/blenkernel/intern/mesh_convert.cc
+++ b/source/blender/blenkernel/intern/mesh_convert.cc
@@ -120,9 +120,6 @@ void BKE_mesh_from_metaball(ListBase *lb, Mesh *me)
     }
 
     BKE_mesh_update_customdata_pointers(me, true);
-
-    BKE_mesh_normals_tag_dirty(me);
-
     BKE_mesh_calc_edges(me, true, false);
   }
 }
@@ -514,7 +511,6 @@ Mesh *BKE_mesh_new_nomain_from_curve_displist(const Object *ob, const ListBase *
   }
 
   mesh = BKE_mesh_new_nomain(totvert, totedge, 0, totloop, totpoly);
-  BKE_mesh_normals_tag_dirty(mesh);
 
   if (totvert != 0) {
     memcpy(mesh->mvert, allvert, totvert * sizeof(MVert));
diff --git a/source/blender/blenkernel/intern/mesh_remesh_voxel.cc b/source/blender/blenkernel/intern/mesh_remesh_voxel.cc
index 7be4a6f2f94..02c9f61957d 100644
--- a/source/blender/blenkernel/intern/mesh_remesh_voxel.cc
+++ b/source/blender/blenkernel/intern/mesh_remesh_voxel.cc
@@ -140,7 +140,6 @@ static Mesh *remesh_quadriflow(const Mesh *input_mesh,
   }
 
   BKE_mesh_calc_edges(mesh, false, false);
-  BKE_mesh_calc_normals(mesh);
 
   MEM_freeN(qrd.out_faces);
   MEM_freeN(qrd.out_verts);
@@ -257,7 +256,6 @@ static Mesh *remesh_voxel_volume_to_mesh(const openvdb::FloatGrid::Ptr level_set
   }
 
   BKE_mesh_calc_edges(mesh, false, false);
-  BKE_mesh_normals_tag_dirty(mesh);
 
   return mesh;
 }
diff --git a/source/blender/blenkernel/intern/modifier.c b/source/blender/blenkernel/intern/modifier.c
index f4703b32582..e7ee8caf0eb 100644
--- a/source/blender/blenkernel/intern/modifier.c
+++ b/source/blender/blenkernel/intern/modifier.c
@@ -944,8 +944,10 @@ static void modwrap_dependsOnNormals(Mesh *me)
       break;
     }
     case ME_WRAPPER_TYPE_SUBD:
+      /* Not an expected case. */
+      break;
     case ME_WRAPPER_TYPE_MDATA:
-      BKE_mesh_calc_normals(me);
+      /* Normals are calculated lazily. */
       break;
   }
 }
@@ -992,7 +994,7 @@ void BKE_modifier_deform_vertsEM(ModifierData *md,
 {
   const ModifierTypeInfo *mti = BKE_modifier_get_info(md->type);
   if (me && mti->dependsOnNormals && mti->dependsOnNormals(md)) {
-    BKE_mesh_calc_normals(me);
+    modwrap_dependsOnNormals(me);
   }
   mti->deformVertsEM(md, ctx, em, me, vertexCos, numVerts);
 }
diff --git a/source/blender/blenkernel/intern/multires_reshape_apply_base.c b/source/blender/blenkernel/intern/multires_reshape_apply_base.c
index 65ba7b64d83..837b64affa8 100644
--- a/source/blender/blenkernel/intern/multires_reshape_apply_base.c
+++ b/source/blender/blenkernel/intern/multires_reshape_apply_base.c
@@ -156,7 +156,7 @@ void multires_reshape_apply_base_refit_base_mesh(MultiresReshapeContext *reshape
   /* Vertices were moved around, need to update normals after all the vertices are updated
    * Probably this is possible to do in the loop above, but this is rather tricky because
    * we don't know all needed vertices' coordinates there yet. */
-  BKE_mesh_calc_normals(base_mesh);
+  BKE_mesh_normals_tag_dirty(base_mesh);
 }
 
 void multires_reshape_apply_base_refine_from_base(MultiresReshapeContext *reshape_context)
diff --git a/source/blender/blenkernel/intern/subdiv_mesh.c b/source/blender/blenkernel/intern/subdiv_mesh.c
index 83e4336e3b1..83427adcb43 100644
--- a/source/blender/blenkernel/intern/subdiv_mesh.c
+++ b/source/blender/blenkernel/intern/subdiv_mesh.c
@@ -1155,7 +1155,7 @@ Mesh *BKE_subdiv_to_mesh(Subdiv *subdiv,
    * calculation. Since vertex normals are supposed to be a consistent cache, don't bother
    * calculating them here. The work may have been pointless anyway if the mesh is deformed or
    * changed afterwards. */
-  BKE_mesh_normals_tag_dirty(result);
+  BLI_assert(BKE_mesh_vertex_normals_are_dirty(result) || BKE_mesh_poly_normals_are_dirty(result));
   /* Free used memory. */
   subdiv_mesh_context_free(&subdiv_context);
   return result;
diff --git a/source/blender/blenkernel/intern/volume_to_mesh.cc b/source/blender/blenkernel/intern/volume_to_mesh.cc
index 8544d6c9c77..ef75d3d2482 100644
--- a/source/blender/blenkernel/intern/volume_to_mesh.cc
+++ b/source/blender/blenkernel/intern/volume_to_mesh.cc
@@ -183,7 +183,6 @@ Mesh *volume_to_mesh(const openvdb::GridBase &grid,
                               {mesh->mloop, mesh->totloop});
 
   BKE_mesh_calc_edges(mesh, false, false);
-  BKE_mesh_normals_tag_dirty(mesh);
 
   return mesh;
 }
diff --git a/source/blender/editors/mesh/editmesh_mask_extract.c b/source/blender/editors/mesh/editmesh_mask_extract.c
index d3fc83eedd7..7634ce6af9e 100644
--- a/source/blender/editors/mesh/editmesh_mask_extract.c
+++ b/source/blender/editors/mesh/editmesh_mask_extract.c
@@ -230,8 +230,6 @@ static int geometry_extract_apply(bContext *C,
     }
   }
 
-  BKE_mesh_calc_normals(new_ob->data);
-
   WM_event_add_notifier(C, NC_OBJECT | ND_MODIFIER, new_ob);
   BKE_mesh_batch_cache_dirty_tag(new_ob->data, BKE_MESH_BATCH_DIRTY_ALL);
   DEG_relations_tag_update(bmain);
@@ -551,7 +549,6 @@ static int paint_mask_slice_exec(bContext *C, wmOperator *op)
     CustomData_free_layers(&new_ob_mesh->vdata, CD_PAINT_MASK, new_ob_mesh->totvert);
 
     BKE_mesh_nomain_to_mesh(new_ob_mesh, new_ob->data, new_ob, &CD_MASK_MESH, true);
-    BKE_mesh_calc_normals(new_ob->data);
     BKE_mesh_copy_parameters_for_eval(new_ob->data, mesh);
     WM_event_add_notifier(C, NC_OBJECT | ND_MODIFIER, new_ob);
     BKE_mesh_batch_cache_dirty_tag(new_ob->data, BKE_MESH_BATCH_DIRTY_ALL);
@@ -561,7 +558,6 @@ static int paint_mask_slice_exec(bContext *C, wmOperator *op)
   }
 
   BKE_mesh_nomain_to_mesh(new_mesh, ob->data, ob, &CD_MASK_MESH, true);
-  BKE_mesh_calc_normals(ob->data);
 
   if (ob->mode == OB_MODE_SCULPT) {
     SculptSession *ss = ob->sculpt;
diff --git a/source/blender/editors/mesh/mesh_data.c b/source/blender/editors/mesh/mesh_data.c
index 6f5c9d410c7..f6f4260b762 100644
--- a/source/blender/editors/mesh/mesh_data.c
+++ b/source/blender/editors/mesh/mesh_data.c
@@ -1092,7 +1092,8 @@ void ED_mesh_update(Mesh *mesh, bContext *C, bool calc_edges, bool calc_edges_lo
   /* Default state is not to have tessface's so make sure this is the case. */
   BKE_mesh_tessface_clear(mesh);
 
-  BKE_mesh_calc_normals(mesh);
+  /* Tag lazily calculated data as dirty. */
+  BKE_mesh_normals_tag_dirty(mesh);
 
   DEG_id_tag_update(&mesh->id, 0);
   WM_event_add_notifier(C, NC_GEOM | ND_DATA, mesh);
diff --git a/source/blender/editors/mesh/meshtools.c b/source/blender/editors/mesh/meshtools.c
index d57471b658c..9575fde68f0 100644
--- a/source/blender/editors/mesh/meshtools.c
+++ b/source/blender/editors/mesh/meshtools.c
@@ -681,8 +681,8 @@ int ED_mesh_join_objects_exec(bContext *C, wmOperator *op)
   /* tessface data removed above, no need to update */
   BKE_mesh_update_customdata_pointers(me, false);
 
-  /* update normals in case objects with non-uniform scale are joined */
-  BKE_mesh_calc_normals(me);
+  /* Tag normals dirty because vertex positions could be changed from the original. */
+  BKE_mesh_normals_tag_dirty(me);
 
   /* old material array */
   for (a = 1; a <= ob->totcol; a++) {
diff --git a/source/blender/editors/object/object_remesh.cc b/source/blender/editors/object/object_remesh.cc
index 966df0668ca..39416a5fbe3 100644
--- a/source/blender/editors/object/object_remesh.cc
+++ b/source/blender/editors/object/object_remesh.cc
@@ -885,9 +885,6 @@ static void quadriflow_start_job(void *customdata, short *stop, short *do_update
   BKE_mesh_nomain_to_mesh(new_mesh, mesh, ob, &CD_MASK_MESH, true);
 
   if (qj->smooth_normals) {
-    if (qj->use_mesh_symmetry) {
-      BKE_mesh_calc_normals(static_cast<Mesh *>(ob->data));
-    }
     BKE_mesh_smooth_flag_set(static_cast<Mesh *>(ob->data), true);
   }
 
diff --git a/source/blender/editors/object/object_transform.cc b/source/blender/editors/object/object_transform.cc
index 976fe683f95..798f34e26d9 100644
--- a/source/blender/editors/object/object_transform.cc
+++ b/source/blender/editors/object/object_transform.cc
@@ -884,9 +884,6 @@ static int apply_objects_internal(bContext *C,
 
       /* adjust data */
       BKE_mesh_transform(me, mat, true);
-
-      /* If normal layers exist, they are now dirty. */
-      BKE_mesh_normals_tag_dirty(me);
     }
     else if (ob->type == OB_ARMATURE) {
       bArmature *arm = static_cast<bArmature *>(ob->data);
diff --git a/source/blender/editors/sculpt_paint/paint_mask.c b/source/blender/editors/sculpt_paint/paint_mask.c
index 5929aa75b45..3ca686e9351 100644
--- a/source/blender/editors/sculpt_paint/paint_mask.c
+++ b/source/blender/editors/sculpt_paint/paint_mask.c
@@ -950,7 +950,6 @@ static void sculpt_gesture_trim_normals_update(SculptGestureContext *sgcontext)
 {
   SculptGestureTrimOperation *trim_operation = (SculptGestureTrimOperation *)sgcontext->operation;
   Mesh *trim_mesh = trim_operation->mesh;
-  BKE_mesh_calc_normals(trim_mesh);
 
   const BMAllocTemplate allocsize = BMALLOC_TEMPLATE_FROM_ME(trim_mesh);
   BMesh *bm;
@@ -1288,7 +1287,6 @@ static void sculpt_gesture_apply_trim(SculptGestureContext *sgcontext)
                                             }),
                                             sculpt_mesh);
   BM_mesh_free(bm);
-  BKE_mesh_normals_tag_dirty(result);
   BKE_mesh_nomain_to_mesh(
       result, sgcontext->vc.obact->data, sgcontext->vc.obact, &CD_MASK_MESH, true);
 }
diff --git a/source/blender/editors/sculpt_paint/sculpt.c b/source/blender/editors/sculpt_paint/sculpt.c
index bbbed32e316..8807032bf69 100644
--- a/source/blender/editors/sculpt_paint/sculpt.c
+++ b/source/blender/editors/sculpt_paint/sculpt.c
@@ -3097,8 +3097,7 @@ void SCULPT_vertcos_to_key(Object *ob, KeyBlock *kb, const float (*vertCos)[3])
     for (a = 0; a < me->totvert; a++, mvert++) {
       copy_v3_v3(mvert->co, vertCos[a]);
     }
-
-    BKE_mesh_calc_normals(me);
+    BKE_mesh_normals_tag_dirty(me);
   }
 
   /* Apply new coords on active key block, no need to re-allocate kb->data here! */
diff --git a/source/blender/editors/sculpt_paint/sculpt_ops.c b/source/blender/editors/sculpt_paint/sculpt_ops.c
index 9581bf2071c..49286ce3308 100644
--- a/source/blender/editors/sculpt_paint/sculpt_ops.c
+++ b/source/blender/editors/sculpt_paint/sculpt_ops.c
@@ -245,7 +245,7 @@ static int sculpt_symmetrize_exec(bContext *C, wmOperator *op)
       BKE_mesh_mirror_apply_mirror_on_axis(bmain, mesh, sd->symmetrize_direction, dist);
 
       ED_sculpt_undo_geometry_end(ob);
-      BKE_mesh_calc_normals(ob->data);
+      BKE_mesh_normals_tag_dirty(mesh);
       BKE_mesh_batch_cache_dirty_tag(ob->data, BKE_MESH_BATCH_DIRTY_ALL);
 
       break;
diff --git a/source/blender/editors/sculpt_paint/sculpt_undo.c b/source/blender/editors/sculpt_paint/sculpt_undo.c
index eae90359dfd..5867dc558de 100644
--- a/source/blender/editors/sculpt_paint/sculpt_undo.c
+++ b/source/blender/editors/sculpt_paint/sculpt_undo.c
@@ -854,7 +854,7 @@ static void sculpt_undo_restore_list(bContext *C, Depsgraph *depsgraph, ListBase
 
     if (tag_update) {
       Mesh *mesh = ob->data;
-      BKE_mesh_calc_normals(mesh);
+      BKE_mesh_normals_tag_dirty(mesh);
 
       BKE_sculptsession_free_deformMats(ss);
     }
diff --git a/source/blender/geometry/intern/mesh_merge_by_distance.cc b/source/blender/geometry/intern/mesh_merge_by_distance.cc
index 9bb1cbb324e..e45b84632ab 100644
--- a/source/blender/geometry/intern/mesh_merge_by_distance.cc
+++ b/source/blender/geometry/intern/mesh_merge_by_distance.cc
@@ -1580,10 +1580,6 @@ static Mesh *create_merged_mesh(const Mesh &mesh,
   BLI_assert((int)r_i == result_npolys);
   BLI_assert(loop_cur == result_nloops);
 
-  /* We could only update the normals of the elements in context, but the next modifier can make it
-   * dirty anyway which would make the work useless. */
-  BKE_mesh_normals_tag_dirty(result);
-
   return result;
 }
 
diff --git a/source/blender/geometry/intern/realize_instances.cc b/source/blender/geometry/intern/realize_instances.cc
index 0a0f01c1ff2..f3f0e5b1fce 100644
--- a/source/blender/geometry/intern/realize_instances.cc
+++ b/source/blender/geometry/intern/realize_instances.cc
@@ -1015,8 +1015,6 @@ static void execute_realize_mesh_tasks(const RealizeInstancesOptions &options,
   if (vertex_ids) {
     vertex_ids.save();
   }
-
-  BKE_mesh_normals_tag_dirty(dst_mesh);
 }
 
 /** \} */
diff --git a/source/blender/io/alembic/intern/abc_reader_mesh.cc b/source/blender/io/alembic/intern/abc_reader_mesh.cc
index fe2b0470432..9b65707bc91 100644
--- a/source/blender/io/alembic/intern/abc_reader_mesh.cc
+++ b/source/blender/io/alembic/intern/abc_reader_mesh.cc
@@ -245,7 +245,7 @@ static void read_mpolys(CDStreamConfig &config, const AbcMeshData &mesh_data)
 static void process_no_normals(CDStreamConfig &config)
 {
   /* Absence of normals in the Alembic mesh is interpreted as 'smooth'. */
-  BKE_mesh_calc_normals(config.mesh);
+  BKE_mesh_normals_tag_dirty(config.mesh);
 }
 
 static void process_loop_normals(CDStreamConfig &config, const N3fArraySamplePtr loop_normals_ptr)
diff --git a/source/blender/io/collada/MeshImporter.cpp b/source/blender/io/collada/MeshImporter.cpp
index fc94e912417..cdd35d23daf 100644
--- a/source/blender/io/collada/MeshImporter.cpp
+++ b/source/blender/io/collada/MeshImporter.cpp
@@ -1057,7 +1057,6 @@ Object *MeshImporter::create_mesh_object(
   Mesh *new_mesh = uid_mesh_map[*geom_uid];
 
   BKE_mesh_assign_object(m_bmain, ob, new_mesh);
-  BKE_mesh_calc_normals(new_mesh);
 
   /* Because BKE_mesh_assign_object would have already decreased it... */
   id_us_plus(&old_mesh->id);
diff --git a/source/blender/makesrna/intern/rna_mesh_api.c b/source/blender/makesrna/intern/rna_mesh_api.c
index b1ebe583afc..8447074a3ef 100644
--- a/source/blender/makesrna/intern/rna_mesh_api.c
+++ b/source/blender/makesrna/intern/rna_mesh_api.c
@@ -159,7 +159,6 @@ static void rna_Mesh_normals_split_custom_set_from_vertices(Mesh *mesh,
 static void rna_Mesh_transform(Mesh *mesh, float mat[16], bool shape_keys)
 {
   BKE_mesh_transform(mesh, (float(*)[4])mat, shape_keys);
-  BKE_mesh_normals_tag_dirty(mesh);
 
   DEG_id_tag_update(&mesh->id, 0);
 }
diff --git a/source/blender/modifiers/intern/MOD_array.c b/source/blender/modifiers/intern/MOD_array.c
index 758858c8b1d..c44a4e0b438 100644
--- a/source/blender/modifiers/intern/MOD_array.c
+++ b/source/blender/modifiers/intern/MOD_array.c
@@ -789,13 +789,6 @@ static Mesh *arrayModifier_doArray(ArrayModifierData *amd,
     MEM_freeN(full_doubles_map);
   }
 
-  /* In case org dm has dirty normals, or we made some merging, mark normals as dirty in new mesh!
-   * TODO: we may need to set other dirty flags as well?
-   */
-  if (use_recalc_normals) {
-    BKE_mesh_normals_tag_dirty(result);
-  }
-
   if (vgroup_start_cap_remap) {
     MEM_freeN(vgroup_start_cap_remap);
   }
diff --git a/source/blender/modifiers/intern/MOD_bevel.c b/source/blender/modifiers/intern/MOD_bevel.c
index b6cceade4e2..a7364af10a3 100644
--- a/source/blender/modifiers/intern/MOD_bevel.c
+++ b/source/blender/modifiers/intern/MOD_bevel.c
@@ -229,8 +229,6 @@ static Mesh *modifyMesh(ModifierData *md, const ModifierEvalContext *ctx, Mesh *
 
   BM_mesh_free(bm);
 
-  BKE_mesh_normals_tag_dirty(result);
-
   return result;
 }
 
diff --git a/source/blender/modifiers/intern/MOD_boolean.cc b/source/blender/modifiers/intern/MOD_boolean.cc
index 915428f99da..d47f2a130e3 100644
--- a/source/blender/modifiers/intern/MOD_boolean.cc
+++ b/source/blender/modifiers/intern/MOD_boolean.cc
@@ -501,7 +501,6 @@ static Mesh *modifyMesh(ModifierData *md, const ModifierEvalContext *ctx, Mesh *
         result = BKE_mesh_from_bmesh_for_eval_nomain(bm, nullptr, mesh);
 
         BM_mesh_free(bm);
-        BKE_mesh_normals_tag_dirty(result);
       }
 
       if (result == nullptr) {
@@ -536,7 +535,6 @@ static Mesh *modifyMesh(ModifierData *md, const ModifierEvalContext *ctx, Mesh *
 
           result = BKE_mesh_from_bmesh_for_eval_nomain(bm, nullptr, mesh);
           BM_mesh_free(bm);
-          BKE_mesh_normals_tag_dirty(result);
         }
       }
     }
diff --git a/source/blender/modifiers/intern/MOD_build.c b/source/blender/modifiers/intern/MOD_build.c
index 61959d242d8..687ff04cedf 100644
--- a/source/blender/modifiers/intern/MOD_build.c
+++ b/source/blender/modifiers/intern/MOD_build.c
@@ -263,8 +263,6 @@ static Mesh *modifyMesh(ModifierData *md, const ModifierEvalContext *ctx, struct
   MEM_freeN(edgeMap);
   MEM_freeN(faceMap);
 
-  BKE_mesh_normals_tag_dirty(result);
-
   /* TODO(sybren): also copy flags & tags? */
   return result;
 }
diff --git a/source/blender/modifiers/intern/MOD_collision.c b/source/blender/modifiers/intern/MOD_collision.c
index 1cb308bb2a0..593610f5bad 100644
--- a/source/blender/modifiers/intern/MOD_collision.c
+++ b/source/blender/modifiers/intern/MOD_collision.c
@@ -120,7 +120,7 @@ static void deformVerts(ModifierData *md,
     uint mvert_num = 0;
 
     BKE_mesh_vert_coords_apply(mesh_src, vertexCos);
-    BKE_mesh_calc_normals(mesh_src);
+    BKE_mesh_normals_tag_dirty(mesh_src);
 
     current_time = DEG_get_ctime(ctx->depsgraph);
 
diff --git a/source/blender/modifiers/intern/MOD_decimate.c b/source/blender/modifiers/intern/MOD_decimate.c
index 67515478be5..70f028d6907 100644
--- a/source/blender/modifiers/intern/MOD_decimate.c
+++ b/source/blender/modifiers/intern/MOD_decimate.c
@@ -212,8 +212,6 @@ static Mesh *modifyMesh(ModifierData *md, const ModifierEvalContext *ctx, Mesh *
   TIMEIT_END(decim);
 #endif
 
-  BKE_mesh_normals_tag_dirty(result);
-
   return result;
 }
 
diff --git a/source/blender/modifiers/intern/MOD_edgesplit.c b/source/blender/modifiers/intern/MOD_edgesplit.c
index 14431e5ff2e..49ddcb9a61d 100644
--- a/source/blender/modifiers/intern/MOD_edgesplit.c
+++ b/source/blender/modifiers/intern/MOD_edgesplit.c
@@ -102,7 +102,6 @@ Mesh *doEdgeSplit(const Mesh *mesh, EdgeSplitModifierData *emd)
   result = BKE_mesh_from_bmesh_for_eval_nomain(bm, NULL, mesh);
   BM_mesh_free(bm);
 
-  BKE_mesh_normals_tag_dirty(result);
   return result;
 }
 
diff --git a/source/blender/modifiers/intern/MOD_explode.c b/source/blender/modifiers/intern/MOD_explode.c
index 87ff648f13d..9e2bb79138e 100644
--- a/source/blender/modifiers/intern/MOD_explode.c
+++ b/source/blender/modifiers/intern/MOD_explode.c
@@ -1102,7 +1102,6 @@ static Mesh *explodeMesh(ExplodeModifierData *emd,
   /* finalization */
   BKE_mesh_calc_edges_tessface(explode);
   BKE_mesh_convert_mfaces_to_mpolys(explode);
-  BKE_mesh_normals_tag_dirty(explode);
 
   if (psmd->psys->lattice_deform_data) {
     BKE_lattice_deform_data_destroy(psmd->psys->lattice_deform_data);
diff --git a/source/blender/modifiers/intern/MOD_mask.cc b/source/blender/modifiers/intern/MOD_mask.cc
index cb26bd1b26b..900dee98268 100644
--- a/source/blender/modifiers/intern/MOD_mask.cc
+++ b/source/blender/modifiers/intern/MOD_mask.cc
@@ -748,7 +748,6 @@ static Mesh *modifyMesh(ModifierData *md, const ModifierEvalContext *UNUSED(ctx)
   }
 
   BKE_mesh_calc_edges_loose(result);
-  BKE_mesh_normals_tag_dirty(result);
 
   return result;
 }
diff --git a/source/blender/modifiers/intern/MOD_ocean.c b/source/blender/modifiers/intern/MOD_ocean.c
index 6ded702ceda..fbc5b7c288f 100644
--- a/source/blender/modifiers/intern/MOD_ocean.c
+++ b/source/blender/modifiers/intern/MOD_ocean.c
@@ -302,8 +302,6 @@ static Mesh *generate_ocean_geometry(OceanModifierData *omd, Mesh *mesh_orig, co
     }
   }
 
-  BKE_mesh_normals_tag_dirty(result);
-
   return result;
 }
 
@@ -361,7 +359,6 @@ static Mesh *doOcean(ModifierData *md, const ModifierEvalContext *ctx, Mesh *mes
 
   if (omd->geometry_mode == MOD_OCEAN_GEOM_GENERATE) {
     result = generate_ocean_geometry(omd, mesh, resolution);
-    BKE_mesh_normals_tag_dirty(result);
   }
   else if (omd->geometry_mode == MOD_OCEAN_GEOM_DISPLACE) {
     result = (Mesh *)BKE_id_copy_ex(NULL, &mesh->id, NULL, LIB_ID_COPY_LOCALIZE);
@@ -472,6 +469,8 @@ static Mesh *doOcean(ModifierData *md, const ModifierEvalContext *ctx, Mesh *mes
     }
   }
 
+  BKE_mesh_normals_tag_dirty(mesh);
+
   if (allocated_ocean) {
     BKE_ocean_free(omd->ocean);
     omd->ocean = NULL;
@@ -490,15 +489,7 @@ static Mesh *doOcean(ModifierData *UNUSED(md), const ModifierEvalContext *UNUSED
 
 static Mesh *modifyMesh(ModifierData *md, const ModifierEvalContext *ctx, Mesh *mesh)
 {
-  Mesh *result;
-
-  result = doOcean(md, ctx, mesh);
-
-  if (result != mesh) {
-    BKE_mesh_normals_tag_dirty(result);
-  }
-
-  return result;
+  return doOcean(md, ctx, mesh);
 }
 // #define WITH_OCEANSIM
 static void panel_draw(const bContext *UNUSED(C), Panel *panel)
diff --git a/source/blender/modifiers/intern/MOD_particleinstance.c b/source/blender/modifiers/intern/MOD_particleinstance.c
index 205a1986552..5af95a0f289 100644
--- a/source/blender/modifiers/intern/MOD_particleinstance.c
+++ b/source/blender/modifiers/intern/MOD_particleinstance.c
@@ -530,8 +530,6 @@ static Mesh *modifyMesh(ModifierData *md, const ModifierEvalContext *ctx, Mesh *
   MEM_SAFE_FREE(vert_part_index);
   MEM_SAFE_FREE(vert_part_value);
 
-  BKE_mesh_normals_tag_dirty(result);
-
   return result;
 }
 
diff --git a/source/blender/modifiers/intern/MOD_particlesystem.c b/source/blender/modifiers/intern/MOD_particlesystem.c
index 7df7ba7c1db..032227307e7 100644
--- a/source/blender/modifiers/intern/MOD_particlesystem.c
+++ b/source/blender/modifiers/intern/MOD_particlesystem.c
@@ -158,7 +158,6 @@ static void deformVerts(ModifierData *md,
   /* make new mesh */
   psmd->mesh_final = BKE_mesh_copy_for_eval(mesh_src, false);
   BKE_mesh_vert_coords_apply(psmd->mesh_final, vertexCos);
-  BKE_mesh_calc_normals(psmd->mesh_final);
 
   BKE_mesh_tessface_ensure(psmd->mesh_final);
 
diff --git a/source/blender/modifiers/intern/MOD_remesh.c b/source/blender/modifiers/intern/MOD_remesh.c
index f6f4746f44f..288faee247f 100644
--- a/source/blender/modifiers/intern/MOD_remesh.c
+++ b/source/blender/modifiers/intern/MOD_remesh.c
@@ -206,7 +206,6 @@ static Mesh *modifyMesh(ModifierData *md, const ModifierEvalContext *UNUSED(ctx)
 
   BKE_mesh_copy_parameters_for_eval(result, mesh);
   BKE_mesh_calc_edges(result, true, false);
-  BKE_mesh_normals_tag_dirty(result);
   return result;
 }
 
diff --git a/source/blender/modifiers/intern/MOD_screw.c b/source/blender/modifiers/intern/MOD_screw.c
index 4ace6404388..8166c44539d 100644
--- a/source/blender/modifiers/intern/MOD_screw.c
+++ b/source/blender/modifiers/intern/MOD_screw.c
@@ -384,7 +384,6 @@ static Mesh *modifyMesh(ModifierData *md, const ModifierEvalContext *ctx, Mesh *
 
   mvert_new = result->mvert;
   float(*vert_normals_new)[3] = BKE_mesh_vertex_normals_for_write(result);
-  BKE_mesh_vertex_normals_clear_dirty(result);
   mpoly_new = result->mpoly;
   mloop_new = result->mloop;
   medge_new = result->medge;
@@ -1120,7 +1119,6 @@ static Mesh *modifyMesh(ModifierData *md, const ModifierEvalContext *ctx, Mesh *
   }
 
   if ((ltmd->flag & MOD_SCREW_MERGE) && (screw_ofs == 0.0f)) {
-    Mesh *result_prev = result;
     result = mesh_remove_doubles_on_axis(result,
                                          mvert_new,
                                          totvert,
@@ -1128,13 +1126,10 @@ static Mesh *modifyMesh(ModifierData *md, const ModifierEvalContext *ctx, Mesh *
                                          axis_vec,
                                          ob_axis != NULL ? mtx_tx[3] : NULL,
                                          ltmd->merge_dist);
-    if (result != result_prev) {
-      BKE_mesh_normals_tag_dirty(result);
-    }
   }
 
-  if ((ltmd->flag & MOD_SCREW_NORMAL_CALC) == 0) {
-    BKE_mesh_normals_tag_dirty(result);
+  if ((ltmd->flag & MOD_SCREW_NORMAL_CALC)) {
+    BKE_mesh_vertex_normals_clear_dirty(mesh);
   }
 
   return result;
diff --git a/source/blender/modifiers/intern/MOD_skin.c b/source/blender/modifiers/intern/MOD_skin.c
index b950578ff1b..7f96dcb82fb 100644
--- a/source/blender/modifiers/intern/MOD_skin.c
+++ b/source/blender/modifiers/intern/MOD_skin.c
@@ -1950,8 +1950,6 @@ static Mesh *base_skin(Mesh *origmesh, SkinModifierData *smd, eSkinErrorFlag *r_
   result = BKE_mesh_from_bmesh_for_eval_nomain(bm, NULL, origmesh);
   BM_mesh_free(bm);
 
-  BKE_mesh_normals_tag_dirty(result);
-
   skin_set_orig_indices(result);
 
   return result;
diff --git a/source/blender/modifiers/intern/MOD_solidify_nonmanifold.c b/source/blender/modifiers/intern/MOD_solidify_nonmanifold.c
index 8a84cd0a3bf..8a5b600974c 100644
--- a/source/blender/modifiers/intern/MOD_solidify_nonmanifold.c
+++ b/source/blender/modifiers/intern/MOD_solidify_nonmanifold.c
@@ -2016,8 +2016,6 @@ Mesh *MOD_solidify_nonmanifold_modifyMesh(ModifierData *md,
     }
   }
 
-  BKE_mesh_normals_tag_dirty(result);
-
   /* Make edges. */
   {
     uint i = 0;
diff --git a/source/blender/modifiers/intern/MOD_surface.c b/source/blender/modifiers/intern/MOD_surface.c
index 3e75e325e44..c2869e590bd 100644
--- a/source/blender/modifiers/intern/MOD_surface.c
+++ b/source/blender/modifiers/intern/MOD_surface.c
@@ -129,7 +129,7 @@ static void deformVerts(ModifierData *md,
     MVert *x, *v;
 
     BKE_mesh_vert_coords_apply(surmd->mesh, vertexCos);
-    BKE_mesh_calc_normals(surmd->mesh);
+    BKE_mesh_normals_tag_dirty(surmd->mesh);
 
     mesh_verts_num = surmd->mesh->totvert;
 
diff --git a/source/blender/modifiers/intern/MOD_triangulate.c b/source/blender/modifiers/intern/MOD_triangulate.c
index d7e57c1f6e5..f1e8ef5bf38 100644
--- a/source/blender/modifiers/intern/MOD_triangulate.c
+++ b/source/blender/modifiers/intern/MOD_triangulate.c
@@ -89,8 +89,6 @@ static Mesh *triangulate_mesh(Mesh *mesh,
     me->flag |= ME_EDGEDRAW | ME_EDGERENDER;
   }
 
-  BKE_mesh_normals_tag_dirty(result);
-
   return result;
 }
 
diff --git a/source/blender/modifiers/intern/MOD_wireframe.c b/source/blender/modifiers/intern/MOD_wireframe.c
index dae7d19844e..b657ea87244 100644
--- a/source/blender/modifiers/intern/MOD_wireframe.c
+++ b/source/blender/modifiers/intern/MOD_wireframe.c
@@ -97,8 +97,6 @@ static Mesh *WireframeModifier_do(WireframeModifierData *wmd, Object *ob, Mesh *
   result = BKE_mesh_from_bmesh_for_eval_nomain(bm, NULL, mesh);
   BM_mesh_free(bm);
 
-  BKE_mesh_normals_tag_dirty(result);
-
   return result;
 }
 
diff --git a/source/blender/nodes/geometry/nodes/node_geo_convex_hull.cc b/source/blender/nodes/geometry/nodes/node_geo_convex_hull.cc
index 87f000897ed..877dc05211d 100644
--- a/source/blender/nodes/geometry/nodes/node_geo_convex_hull.cc
+++ b/source/blender/nodes/geometry/nodes/node_geo_convex_hull.cc
@@ -131,8 +131,6 @@ static Mesh *hull_from_bullet(const Mesh *mesh, Span<float3> coords)
   }
 
   plConvexHullDelete(hull);
-
-  BKE_mesh_normals_tag_dirty(result);
   return result;
 }
 
diff --git a/source/blender/nodes/geometry/nodes/node_geo_delete_geometry.cc b/source/blender/nodes/geometry/nodes/node_geo_delete_geometry.cc
index c3b1a141f4a..8a0c900fbde 100644
--- a/source/blender/nodes/geometry/nodes/node_geo_delete_geometry.cc
+++ b/source/blender/nodes/geometry/nodes/node_geo_delete_geometry.cc
@@ -1225,8 +1225,6 @@ static void do_mesh_separation(GeometrySet &geometry_set,
   }
 
   BKE_mesh_calc_edges_loose(mesh_out);
-  /* Tag to recalculate normals later. */
-  BKE_mesh_normals_tag_dirty(mesh_out);
   geometry_set.replace_mesh(mesh_out);
 }
 
diff --git a/source/blender/nodes/geometry/nodes/node_geo_dual_mesh.cc b/source/blender/nodes/geometry/nodes/node_geo_dual_mesh.cc
index 2894e608819..dcd9bcfb034 100644
--- a/source/blender/nodes/geometry/nodes/node_geo_dual_mesh.cc
+++ b/source/blender/nodes/geometry/nodes/node_geo_dual_mesh.cc
@@ -897,7 +897,6 @@ static void calc_dual_mesh(GeometrySet &geometry_set,
     copy_v3_v3(mesh_out->mvert[i].co, vertex_positions[i]);
   }
   memcpy(mesh_out->medge, new_edges.data(), sizeof(MEdge) * new_edges.size());
-  BKE_mesh_normals_tag_dirty(mesh_out);
   geometry_set.replace_mesh(mesh_out);
 }
 
diff --git a/source/blender/nodes/geometry/nodes/node_geo_edge_split.cc b/source/blender/nodes/geometry/nodes/node_geo_edge_split.cc
index c03a340a0c8..84acab47661 100644
--- a/source/blender/nodes/geometry/nodes/node_geo_edge_split.cc
+++ b/source/blender/nodes/geometry/nodes/node_geo_edge_split.cc
@@ -41,8 +41,6 @@ static Mesh *mesh_edge_split(const Mesh &mesh, const IndexMask selection)
   Mesh *result = BKE_mesh_from_bmesh_for_eval_nomain(bm, nullptr, &mesh);
   BM_mesh_free(bm);
 
-  BKE_mesh_normals_tag_dirty(result);
-
   return result;
 }
 
diff --git a/source/blender/nodes/geometry/nodes/node_geo_mesh_primitive_cube.cc b/source/blender/nodes/geometry/nodes/node_geo_mesh_primitive_cube.cc
index e53be5213f6..636ecb8ab41 100644
--- a/source/blender/nodes/geometry/nodes/node_geo_mesh_primitive_cube.cc
+++ b/source/blender/nodes/geometry/nodes/node_geo_mesh_primitive_cube.cc
@@ -407,7 +407,6 @@ Mesh *create_cuboid_mesh(const float3 size,
 
   calculate_polys(config, {mesh->mpoly, mesh->totpoly}, {mesh->mloop, mesh->totloop});
   BKE_mesh_calc_edges(mesh, false, false);
-  BKE_mesh_normals_tag_dirty(mesh);
 
   calculate_uvs(config, mesh);
 
diff --git a/source/blender/nodes/geometry/nodes/node_geo_mesh_subdivide.cc b/source/blender/nodes/geometry/nodes/node_geo_mesh_subdivide.cc
index e1f85be0f80..3c0ccb01673 100644
--- a/source/blender/nodes/geometry/nodes/node_geo_mesh_subdivide.cc
+++ b/source/blender/nodes/geometry/nodes/node_geo_mesh_subdivide.cc
@@ -50,7 +50,6 @@ static void geometry_set_mesh_subdivide(GeometrySet &geometry_set, const int lev
   }
 
   Mesh *mesh_out = BKE_subdiv_to_mesh(subdiv, &mesh_settings, mesh_in);
-  BKE_mesh_normals_tag_dirty(mesh_out);
 
   MeshComponent &mesh_component = geometry_set.get_component_for_write<MeshComponent>();
   mesh_component.replace(mesh_out);
diff --git a/source/blender/nodes/geometry/nodes/node_geo_subdivision_surface.cc b/source/blender/nodes/geometry/nodes/node_geo_subdivision_surface.cc
index a5fe491e12b..4832feac5bd 100644
--- a/source/blender/nodes/geometry/nodes/node_geo_subdivision_surface.cc
+++ b/source/blender/nodes/geometry/nodes/node_geo_subdivision_surface.cc
@@ -119,7 +119,6 @@ static void node_geo_exec(GeoNodeExecParams params)
     }
 
     Mesh *mesh_out = BKE_subdiv_to_mesh(subdiv, &mesh_settings, mesh_in);
-    BKE_mesh_normals_tag_dirty(mesh_out);
 
     mesh_component.replace(mesh_out);
 
diff --git a/source/blender/nodes/geometry/nodes/node_geo_transform.cc b/source/blender/nodes/geometry/nodes/node_geo_transform.cc
index cc115ee3b3f..e95db205920 100644
--- a/source/blender/nodes/geometry/nodes/node_geo_transform.cc
+++ b/source/blender/nodes/geometry/nodes/node_geo_transform.cc
@@ -43,7 +43,6 @@ static void translate_mesh(Mesh &mesh, const float3 translation)
 static void transform_mesh(Mesh &mesh, const float4x4 &transform)
 {
   BKE_mesh_transform(&mesh, transform.values, false);
-  BKE_mesh_normals_tag_dirty(&mesh);
 }
 
 static void translate_pointcloud(PointCloud &pointcloud, const float3 translation)
diff --git a/source/blender/nodes/geometry/nodes/node_geo_triangulate.cc b/source/blender/nodes/geometry/nodes/node_geo_triangulate.cc
index 76cdbfb140f..992470e8279 100644
--- a/source/blender/nodes/geometry/nodes/node_geo_triangulate.cc
+++ b/source/blender/nodes/geometry/nodes/node_geo_triangulate.cc
@@ -62,7 +62,6 @@ static Mesh *triangulate_mesh_selection(const Mesh &mesh,
   BM_mesh_triangulate(bm, quad_method, ngon_method, min_vertices, true, nullptr, nullptr, nullptr);
   Mesh *result = BKE_mesh_from_bmesh_for_eval_nomain(bm, &cd_mask_extra, &mesh);
   BM_mesh_free(bm);
-  BKE_mesh_normals_tag_dirty(result);
   return result;
 }
 
diff --git a/source/blender/nodes/geometry/nodes/node_geo_volume_to_mesh.cc b/source/blender/nodes/geometry/nodes/node_geo_volume_to_mesh.cc
index c30c05bdd0d..e5827c24320 100644
--- a/source/blender/nodes/geometry/nodes/node_geo_volume_to_mesh.cc
+++ b/source/blender/nodes/geometry/nodes/node_geo_volume_to_mesh.cc
@@ -139,7 +139,6 @@ static Mesh *create_mesh_from_volume_grids(Span<openvdb::GridBase::ConstPtr> gri
   }
 
   BKE_mesh_calc_edges(mesh, false, false);
-  BKE_mesh_normals_tag_dirty(mesh);
 
   return mesh;
 }