Mesh: Move bevel weight out of MVert and MEdge

As described in T95966, the goal is to move to a "struct of arrays"
approach rather than gathering an arbitrary set of data in hard-coded
structs. This has performance benefits, but also code complexity
benefits (this patch removes plenty of code, though the boilerplate
for the new operators outweighs that here).

To mirror the internal change, the options for storing mesh bevel
weights are converted into operators that add or remove the layer,
like for some other layers.

The most complex change is to the solidify modifier, where bevel
weights had special handling. Other than that, most changes are
removing clearing of the weights, boilerplate for the add/remove
operators, and removing the manual transfer of bevel weights
in bmesh - mesh conversion.

Eventually bevel weights can become a fully generic attribute,
but for now this patch aims to avoid most functional changes.

Bevel weights are still written and read from the mesh in the old way,
so neither forward nor backward compatibility are affected. As described
in T95965, writing in the old format will be done until 4.0.

Differential Revision: https://developer.blender.org/D14077

10 files changed, 78 insertions, 91 deletions

diff --git a/source/blender/blenkernel/intern/customdata.cc b/source/blender/blenkernel/intern/customdata.cc
index a3b9f012e45..24373053896 100644
--- a/source/blender/blenkernel/intern/customdata.cc
+++ b/source/blender/blenkernel/intern/customdata.cc
@@ -1867,7 +1867,7 @@ static const LayerTypeInfo LAYERTYPEINFO[CD_NUMTYPES] = {
     /* 28: CD_SHAPEKEY */
     {sizeof(float[3]), "", 0, N_("ShapeKey"), nullptr, nullptr, layerInterp_shapekey},
     /* 29: CD_BWEIGHT */
-    {sizeof(float), "", 0, N_("BevelWeight"), nullptr, nullptr, layerInterp_bweight},
+    {sizeof(MFloatProperty), "MFloatProperty", 1, nullptr, nullptr, nullptr, layerInterp_bweight},
     /* 30: CD_CREASE */
     /* NOTE: we do not interpolate crease data as it should be either inherited for subdivided
      * edges, or for vertex creases, only present on the original vertex. */
@@ -2108,23 +2108,23 @@ static const char *LAYERTYPENAMES[CD_NUMTYPES] = {
 };
 
 const CustomData_MeshMasks CD_MASK_BAREMESH = {
-    /* vmask */ CD_MASK_MVERT | CD_MASK_BWEIGHT,
-    /* emask */ CD_MASK_MEDGE | CD_MASK_BWEIGHT,
+    /* vmask */ CD_MASK_MVERT,
+    /* emask */ CD_MASK_MEDGE,
     /* fmask */ 0,
     /* pmask */ CD_MASK_MPOLY | CD_MASK_FACEMAP,
     /* lmask */ CD_MASK_MLOOP,
 };
 const CustomData_MeshMasks CD_MASK_BAREMESH_ORIGINDEX = {
-    /* vmask */ CD_MASK_MVERT | CD_MASK_BWEIGHT | CD_MASK_ORIGINDEX,
-    /* emask */ CD_MASK_MEDGE | CD_MASK_BWEIGHT | CD_MASK_ORIGINDEX,
+    /* vmask */ CD_MASK_MVERT | CD_MASK_ORIGINDEX,
+    /* emask */ CD_MASK_MEDGE | CD_MASK_ORIGINDEX,
     /* fmask */ 0,
     /* pmask */ CD_MASK_MPOLY | CD_MASK_FACEMAP | CD_MASK_ORIGINDEX,
     /* lmask */ CD_MASK_MLOOP,
 };
 const CustomData_MeshMasks CD_MASK_MESH = {
     /* vmask */ (CD_MASK_MVERT | CD_MASK_MDEFORMVERT | CD_MASK_MVERT_SKIN | CD_MASK_PAINT_MASK |
-                 CD_MASK_PROP_ALL | CD_MASK_CREASE),
-    /* emask */ (CD_MASK_MEDGE | CD_MASK_FREESTYLE_EDGE | CD_MASK_PROP_ALL),
+                 CD_MASK_PROP_ALL | CD_MASK_CREASE | CD_MASK_BWEIGHT),
+    /* emask */ (CD_MASK_MEDGE | CD_MASK_FREESTYLE_EDGE | CD_MASK_PROP_ALL | CD_MASK_BWEIGHT),
     /* fmask */ 0,
     /* pmask */
     (CD_MASK_MPOLY | CD_MASK_FACEMAP | CD_MASK_FREESTYLE_FACE | CD_MASK_PROP_ALL |
@@ -2136,8 +2136,8 @@ const CustomData_MeshMasks CD_MASK_MESH = {
 const CustomData_MeshMasks CD_MASK_DERIVEDMESH = {
     /* vmask */ (CD_MASK_ORIGINDEX | CD_MASK_MDEFORMVERT | CD_MASK_SHAPEKEY | CD_MASK_MVERT_SKIN |
                  CD_MASK_PAINT_MASK | CD_MASK_ORCO | CD_MASK_CLOTH_ORCO | CD_MASK_PROP_ALL |
-                 CD_MASK_CREASE),
-    /* emask */ (CD_MASK_ORIGINDEX | CD_MASK_FREESTYLE_EDGE | CD_MASK_PROP_ALL),
+                 CD_MASK_CREASE | CD_MASK_BWEIGHT),
+    /* emask */ (CD_MASK_ORIGINDEX | CD_MASK_FREESTYLE_EDGE | CD_MASK_BWEIGHT | CD_MASK_PROP_ALL),
     /* fmask */ (CD_MASK_ORIGINDEX | CD_MASK_ORIGSPACE | CD_MASK_PREVIEW_MCOL | CD_MASK_TANGENT),
     /* pmask */
     (CD_MASK_ORIGINDEX | CD_MASK_FREESTYLE_FACE | CD_MASK_FACEMAP | CD_MASK_PROP_ALL |
@@ -5175,7 +5175,7 @@ void CustomData_data_transfer(const MeshPairRemap *me_remap,
   else {
     const LayerTypeInfo *type_info = layerType_getInfo(data_type);
 
-    /* NOTE: we can use 'fake' CDLayers, like e.g. for crease, bweight, etc. :/. */
+    /* NOTE: we can use 'fake' CDLayers for crease :/. */
     data_size = (size_t)type_info->size;
     data_step = laymap->elem_size ? laymap->elem_size : data_size;
     data_offset = laymap->data_offset;
diff --git a/source/blender/blenkernel/intern/data_transfer.c b/source/blender/blenkernel/intern/data_transfer.c
index 6fbdade08f8..6c7715c625e 100644
--- a/source/blender/blenkernel/intern/data_transfer.c
+++ b/source/blender/blenkernel/intern/data_transfer.c
@@ -192,7 +192,7 @@ int BKE_object_data_transfer_dttype_to_cdtype(const int dtdata_type)
     case DT_TYPE_SKIN:
       return CD_MVERT_SKIN;
     case DT_TYPE_BWEIGHT_VERT:
-      return CD_FAKE_BWEIGHT;
+      return CD_BWEIGHT;
 
     case DT_TYPE_SHARP_EDGE:
       return CD_FAKE_SHARP;
@@ -201,7 +201,7 @@ int BKE_object_data_transfer_dttype_to_cdtype(const int dtdata_type)
     case DT_TYPE_CREASE:
       return CD_FAKE_CREASE;
     case DT_TYPE_BWEIGHT_EDGE:
-      return CD_FAKE_BWEIGHT;
+      return CD_BWEIGHT;
     case DT_TYPE_FREESTYLE_EDGE:
       return CD_FREESTYLE_EDGE;
 
@@ -928,38 +928,6 @@ static bool data_transfer_layersmapping_generate(ListBase *r_map,
       }
       return true;
     }
-    if (cddata_type == CD_FAKE_BWEIGHT) {
-      const size_t elem_size = sizeof(*((MVert *)NULL));
-      const size_t data_size = sizeof(((MVert *)NULL)->bweight);
-      const size_t data_offset = offsetof(MVert, bweight);
-      const uint64_t data_flag = 0;
-
-      if (!(me_src->cd_flag & ME_CDFLAG_VERT_BWEIGHT)) {
-        if (use_delete) {
-          me_dst->cd_flag &= ~ME_CDFLAG_VERT_BWEIGHT;
-        }
-        return true;
-      }
-      me_dst->cd_flag |= ME_CDFLAG_VERT_BWEIGHT;
-      if (r_map) {
-        data_transfer_layersmapping_add_item(r_map,
-                                             cddata_type,
-                                             mix_mode,
-                                             mix_factor,
-                                             mix_weights,
-                                             BKE_mesh_verts(me_src),
-                                             BKE_mesh_verts_for_write(me_dst),
-                                             me_src->totvert,
-                                             me_dst->totvert,
-                                             elem_size,
-                                             data_size,
-                                             data_offset,
-                                             data_flag,
-                                             data_transfer_interp_char,
-                                             interp_data);
-      }
-      return true;
-    }
     if (cddata_type == CD_FAKE_MDEFORMVERT) {
       bool ret;
 
@@ -1045,38 +1013,7 @@ static bool data_transfer_layersmapping_generate(ListBase *r_map,
       }
       return true;
     }
-    if (cddata_type == CD_FAKE_BWEIGHT) {
-      const size_t elem_size = sizeof(*((MEdge *)NULL));
-      const size_t data_size = sizeof(((MEdge *)NULL)->bweight);
-      const size_t data_offset = offsetof(MEdge, bweight);
-      const uint64_t data_flag = 0;
 
-      if (!(me_src->cd_flag & ME_CDFLAG_EDGE_BWEIGHT)) {
-        if (use_delete) {
-          me_dst->cd_flag &= ~ME_CDFLAG_EDGE_BWEIGHT;
-        }
-        return true;
-      }
-      me_dst->cd_flag |= ME_CDFLAG_EDGE_BWEIGHT;
-      if (r_map) {
-        data_transfer_layersmapping_add_item(r_map,
-                                             cddata_type,
-                                             mix_mode,
-                                             mix_factor,
-                                             mix_weights,
-                                             BKE_mesh_edges(me_src),
-                                             BKE_mesh_edges_for_write(me_dst),
-                                             me_src->totedge,
-                                             me_dst->totedge,
-                                             elem_size,
-                                             data_size,
-                                             data_offset,
-                                             data_flag,
-                                             data_transfer_interp_char,
-                                             interp_data);
-      }
-      return true;
-    }
     if (r_map && ELEM(cddata_type, CD_FAKE_SHARP, CD_FAKE_SEAM)) {
       const size_t elem_size = sizeof(*((MEdge *)NULL));
       const size_t data_size = sizeof(((MEdge *)NULL)->flag);
diff --git a/source/blender/blenkernel/intern/mball_tessellate.c b/source/blender/blenkernel/intern/mball_tessellate.c
index 3917c020759..49963c333ec 100644
--- a/source/blender/blenkernel/intern/mball_tessellate.c
+++ b/source/blender/blenkernel/intern/mball_tessellate.c
@@ -1447,7 +1447,6 @@ Mesh *BKE_mball_polygonize(Depsgraph *depsgraph, Scene *scene, Object *ob)
   MVert *mvert = CustomData_add_layer(&mesh->vdata, CD_MVERT, CD_CONSTRUCT, NULL, mesh->totvert);
   for (int i = 0; i < mesh->totvert; i++) {
     copy_v3_v3(mvert[i].co, process.co[i]);
-    mvert->bweight = 0;
     mvert->flag = 0;
   }
   MEM_freeN(process.co);
diff --git a/source/blender/blenkernel/intern/mesh.cc b/source/blender/blenkernel/intern/mesh.cc
index c82d9be008d..a5b50824542 100644
--- a/source/blender/blenkernel/intern/mesh.cc
+++ b/source/blender/blenkernel/intern/mesh.cc
@@ -251,6 +251,7 @@ static void mesh_blend_write(BlendWriter *writer, ID *id, const void *id_address
     if (!BLO_write_is_undo(writer)) {
       BKE_mesh_legacy_convert_hide_layers_to_flags(mesh);
       BKE_mesh_legacy_convert_material_indices_to_mpoly(mesh);
+      BKE_mesh_legacy_bevel_weight_from_layers(mesh);
       /* When converting to the old mesh format, don't save redundant attributes. */
       names_to_skip.add_multiple_new({".hide_vert", ".hide_edge", ".hide_poly"});
 
@@ -348,6 +349,7 @@ static void mesh_blend_read_data(BlendDataReader *reader, ID *id)
   if (!BLO_read_data_is_undo(reader)) {
     BKE_mesh_legacy_convert_flags_to_hide_layers(mesh);
     BKE_mesh_legacy_convert_mpoly_to_material_indices(mesh);
+    BKE_mesh_legacy_bevel_weight_to_layers(mesh);
   }
 
   /* We don't expect to load normals from files, since they are derived data. */
diff --git a/source/blender/blenkernel/intern/mesh_boolean_convert.cc b/source/blender/blenkernel/intern/mesh_boolean_convert.cc
index 4b08e0b2ed5..7a04e45fe00 100644
--- a/source/blender/blenkernel/intern/mesh_boolean_convert.cc
+++ b/source/blender/blenkernel/intern/mesh_boolean_convert.cc
@@ -381,7 +381,6 @@ static void copy_vert_attributes(Mesh *dest_mesh,
                                  int mv_index,
                                  int index_in_orig_me)
 {
-  mv->bweight = orig_mv->bweight;
   mv->flag = orig_mv->flag;
 
   /* For all layers in the orig mesh, copy the layer information. */
@@ -450,7 +449,6 @@ static void copy_edge_attributes(Mesh *dest_mesh,
                                  int medge_index,
                                  int index_in_orig_me)
 {
-  medge->bweight = orig_medge->bweight;
   medge->crease = orig_medge->crease;
   medge->flag = orig_medge->flag;
   CustomData *target_cd = &dest_mesh->edata;
diff --git a/source/blender/blenkernel/intern/mesh_convert.cc b/source/blender/blenkernel/intern/mesh_convert.cc
index 756529473f4..b7d8972aa7b 100644
--- a/source/blender/blenkernel/intern/mesh_convert.cc
+++ b/source/blender/blenkernel/intern/mesh_convert.cc
@@ -118,7 +118,7 @@ static void make_edges_mdata_extend(Mesh &mesh)
       BLI_edgehashIterator_getKey(ehi, &medge->v1, &medge->v2);
       BLI_edgehashIterator_setValue(ehi, POINTER_FROM_UINT(e_index));
 
-      medge->crease = medge->bweight = 0;
+      medge->crease = 0;
       medge->flag = ME_EDGEDRAW | ME_EDGERENDER;
     }
     BLI_edgehashIterator_free(ehi);
diff --git a/source/blender/blenkernel/intern/mesh_debug.cc b/source/blender/blenkernel/intern/mesh_debug.cc
index 1826a77d6f4..8a9ce901923 100644
--- a/source/blender/blenkernel/intern/mesh_debug.cc
+++ b/source/blender/blenkernel/intern/mesh_debug.cc
@@ -30,12 +30,6 @@
 static void mesh_debug_info_from_cd_flag(const Mesh *me, DynStr *dynstr)
 {
   BLI_dynstr_append(dynstr, "'cd_flag': {");
-  if (me->cd_flag & ME_CDFLAG_VERT_BWEIGHT) {
-    BLI_dynstr_append(dynstr, "'VERT_BWEIGHT', ");
-  }
-  if (me->cd_flag & ME_CDFLAG_EDGE_BWEIGHT) {
-    BLI_dynstr_append(dynstr, "'EDGE_BWEIGHT', ");
-  }
   if (me->cd_flag & ME_CDFLAG_EDGE_CREASE) {
     BLI_dynstr_append(dynstr, "'EDGE_CREASE', ");
   }
diff --git a/source/blender/blenkernel/intern/mesh_legacy_convert.cc b/source/blender/blenkernel/intern/mesh_legacy_convert.cc
index 2f67e303095..10fc8ff3195 100644
--- a/source/blender/blenkernel/intern/mesh_legacy_convert.cc
+++ b/source/blender/blenkernel/intern/mesh_legacy_convert.cc
@@ -918,6 +918,67 @@ void BKE_mesh_add_mface_layers(CustomData *fdata, CustomData *ldata, int total)
 /** \} */
 
 /* -------------------------------------------------------------------- */
+/** \name Bevel Weight Conversion
+ * \{ */
+
+void BKE_mesh_legacy_bevel_weight_from_layers(Mesh *mesh)
+{
+  using namespace blender;
+  MutableSpan<MVert> verts = mesh->verts_for_write();
+  if (const float *weights = static_cast<const float *>(
+          CustomData_get_layer(&mesh->vdata, CD_BWEIGHT))) {
+    mesh->cd_flag |= ME_CDFLAG_VERT_BWEIGHT;
+    for (const int i : verts.index_range()) {
+      verts[i].bweight = std::clamp(weights[i], 0.0f, 1.0f) * 255.0f;
+    }
+  }
+  else {
+    mesh->cd_flag &= ~ME_CDFLAG_VERT_BWEIGHT;
+    for (const int i : verts.index_range()) {
+      verts[i].bweight = 0;
+    }
+  }
+  MutableSpan<MEdge> edges = mesh->edges_for_write();
+  if (const float *weights = static_cast<const float *>(
+          CustomData_get_layer(&mesh->edata, CD_BWEIGHT))) {
+    mesh->cd_flag |= ME_CDFLAG_EDGE_BWEIGHT;
+    for (const int i : edges.index_range()) {
+      edges[i].bweight = std::clamp(weights[i], 0.0f, 1.0f) * 255.0f;
+    }
+  }
+  else {
+    mesh->cd_flag &= ~ME_CDFLAG_EDGE_BWEIGHT;
+    for (const int i : edges.index_range()) {
+      edges[i].bweight = 0;
+    }
+  }
+}
+
+void BKE_mesh_legacy_bevel_weight_to_layers(Mesh *mesh)
+{
+  using namespace blender;
+  const Span<MVert> verts = mesh->verts();
+  if (mesh->cd_flag & ME_CDFLAG_VERT_BWEIGHT) {
+    float *weights = static_cast<float *>(
+        CustomData_add_layer(&mesh->vdata, CD_BWEIGHT, CD_CONSTRUCT, nullptr, verts.size()));
+    for (const int i : verts.index_range()) {
+      weights[i] = verts[i].bweight / 255.0f;
+    }
+  }
+
+  const Span<MEdge> edges = mesh->edges();
+  if (mesh->cd_flag & ME_CDFLAG_EDGE_BWEIGHT) {
+    float *weights = static_cast<float *>(
+        CustomData_add_layer(&mesh->edata, CD_BWEIGHT, CD_CONSTRUCT, nullptr, edges.size()));
+    for (const int i : edges.index_range()) {
+      weights[i] = edges[i].bweight / 255.0f;
+    }
+  }
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
 /** \name Hide Attribute and Legacy Flag Conversion
  * \{ */
 
diff --git a/source/blender/blenkernel/intern/subdiv_mesh.cc b/source/blender/blenkernel/intern/subdiv_mesh.cc
index dc9fc3dee09..44bdd6e6d06 100644
--- a/source/blender/blenkernel/intern/subdiv_mesh.cc
+++ b/source/blender/blenkernel/intern/subdiv_mesh.cc
@@ -791,7 +791,6 @@ static void subdiv_copy_edge_data(SubdivMeshContext *ctx,
   const int subdiv_edge_index = subdiv_edge - ctx->subdiv_edges;
   if (coarse_edge == nullptr) {
     subdiv_edge->crease = 0;
-    subdiv_edge->bweight = 0;
     subdiv_edge->flag = 0;
     if (!ctx->settings->use_optimal_display) {
       subdiv_edge->flag |= ME_EDGERENDER;
@@ -1138,9 +1137,6 @@ static void subdiv_mesh_vertex_of_loose_edge(const SubdivForeachContext *foreach
                                                subdiv_vertex->co);
   /* Reset flags and such. */
   subdiv_vertex->flag = 0;
-  /* TODO(sergey): This matches old behavior, but we can as well interpolate
-   * it. Maybe even using vertex varying attributes. */
-  subdiv_vertex->bweight = 0.0f;
 }
 
 /** \} */
diff --git a/source/blender/blenkernel/intern/subsurf_ccg.c b/source/blender/blenkernel/intern/subsurf_ccg.c
index 88c260be9ba..0e5f9f30243 100644
--- a/source/blender/blenkernel/intern/subsurf_ccg.c
+++ b/source/blender/blenkernel/intern/subsurf_ccg.c
@@ -879,7 +879,7 @@ static void ccgDM_getFinalVertNo(DerivedMesh *dm, int vertNum, float r_no[3])
 BLI_INLINE void ccgDM_to_MVert(MVert *mv, const CCGKey *key, CCGElem *elem)
 {
   copy_v3_v3(mv->co, CCG_elem_co(key, elem));
-  mv->flag = mv->bweight = 0;
+  mv->flag = 0;
 }
 
 static void ccgDM_copyFinalVertArray(DerivedMesh *dm, MVert *mvert)
@@ -949,7 +949,7 @@ BLI_INLINE void ccgDM_to_MEdge(MEdge *med, const int v1, const int v2, const sho
 {
   med->v1 = v1;
   med->v2 = v2;
-  med->crease = med->bweight = 0;
+  med->crease = 0;
   med->flag = flag;
 }