Mesh: Move edge crease out of MEdge

This is very similar to D14077. There are two differences though.
First is that vertex creases are already stored in a separate layer,
and second is that we can now completely remove use of `Mesh.cd_flag`,
since that information is now inherent to whether the layers exist.

There are two functional differences here:
 * Operators are used to add and remove layers instead of a property.
 * The "crease" attribute can be created and removed by geometry nodes.

The second change should make various geometry nodes slightly faster,
since the "crease" attribute was always processed before. Creases are
now interpolated generically in the CustomData API too, which should
help maintain the values across edits better.

Meshes get an `edge_creases` RNA property like the existing vertex
property, to provide more efficient access to the data in Cycles.

One test failure is expected, where different rounding between float
the old char storage means that 5 additional points are scattered in
a geometry nodes test.

Differential Revision: https://developer.blender.org/D15927

3 files changed, 0 insertions, 86 deletions

diff --git a/source/blender/bmesh/intern/bmesh_construct.c b/source/blender/bmesh/intern/bmesh_construct.c
index 757d006b04d..8b770050ba0 100644
--- a/source/blender/bmesh/intern/bmesh_construct.c
+++ b/source/blender/bmesh/intern/bmesh_construct.c
@@ -507,8 +507,6 @@ void BM_mesh_copy_init_customdata_from_mesh_array(BMesh *bm_dst,
     allocsize = &bm_mesh_allocsize_default;
   }
 
-  char cd_flag = 0;
-
   for (int i = 0; i < me_src_array_len; i++) {
     const Mesh *me_src = me_src_array[i];
     if (i == 0) {
@@ -531,18 +529,12 @@ void BM_mesh_copy_init_customdata_from_mesh_array(BMesh *bm_dst,
       CustomData_merge_mesh_to_bmesh(
           &me_src->pdata, &bm_dst->pdata, CD_MASK_BMESH.pmask, CD_SET_DEFAULT, 0);
     }
-
-    cd_flag |= me_src->cd_flag;
   }
 
-  cd_flag |= BM_mesh_cd_flag_from_bmesh(bm_dst);
-
   CustomData_bmesh_init_pool(&bm_dst->vdata, allocsize->totvert, BM_VERT);
   CustomData_bmesh_init_pool(&bm_dst->edata, allocsize->totedge, BM_EDGE);
   CustomData_bmesh_init_pool(&bm_dst->ldata, allocsize->totloop, BM_LOOP);
   CustomData_bmesh_init_pool(&bm_dst->pdata, allocsize->totface, BM_FACE);
-
-  BM_mesh_cd_flag_apply(bm_dst, cd_flag);
 }
 
 void BM_mesh_copy_init_customdata_from_mesh(BMesh *bm_dst,
diff --git a/source/blender/bmesh/intern/bmesh_mesh_convert.cc b/source/blender/bmesh/intern/bmesh_mesh_convert.cc
index 0bbf425971f..a52f95c1e9d 100644
--- a/source/blender/bmesh/intern/bmesh_mesh_convert.cc
+++ b/source/blender/bmesh/intern/bmesh_mesh_convert.cc
@@ -110,57 +110,6 @@ using blender::MutableSpan;
 using blender::Span;
 using blender::StringRef;
 
-void BM_mesh_cd_flag_ensure(BMesh *bm, Mesh *mesh, const char cd_flag)
-{
-  const char cd_flag_all = BM_mesh_cd_flag_from_bmesh(bm) | cd_flag;
-  BM_mesh_cd_flag_apply(bm, cd_flag_all);
-  if (mesh) {
-    mesh->cd_flag = cd_flag_all;
-  }
-}
-
-void BM_mesh_cd_flag_apply(BMesh *bm, const char cd_flag)
-{
-  /* CustomData_bmesh_init_pool() must run first */
-  BLI_assert(bm->vdata.totlayer == 0 || bm->vdata.pool != nullptr);
-  BLI_assert(bm->edata.totlayer == 0 || bm->edata.pool != nullptr);
-  BLI_assert(bm->pdata.totlayer == 0 || bm->pdata.pool != nullptr);
-
-  if (cd_flag & ME_CDFLAG_VERT_CREASE) {
-    if (!CustomData_has_layer(&bm->vdata, CD_CREASE)) {
-      BM_data_layer_add(bm, &bm->vdata, CD_CREASE);
-    }
-  }
-  else {
-    if (CustomData_has_layer(&bm->vdata, CD_CREASE)) {
-      BM_data_layer_free(bm, &bm->vdata, CD_CREASE);
-    }
-  }
-
-  if (cd_flag & ME_CDFLAG_EDGE_CREASE) {
-    if (!CustomData_has_layer(&bm->edata, CD_CREASE)) {
-      BM_data_layer_add(bm, &bm->edata, CD_CREASE);
-    }
-  }
-  else {
-    if (CustomData_has_layer(&bm->edata, CD_CREASE)) {
-      BM_data_layer_free(bm, &bm->edata, CD_CREASE);
-    }
-  }
-}
-
-char BM_mesh_cd_flag_from_bmesh(BMesh *bm)
-{
-  char cd_flag = 0;
-  if (CustomData_has_layer(&bm->vdata, CD_CREASE)) {
-    cd_flag |= ME_CDFLAG_VERT_CREASE;
-  }
-  if (CustomData_has_layer(&bm->edata, CD_CREASE)) {
-    cd_flag |= ME_CDFLAG_EDGE_CREASE;
-  }
-  return cd_flag;
-}
-
 /* Static function for alloc (duplicate in modifiers_bmesh.c) */
 static BMFace *bm_face_create_from_mpoly(BMesh &bm,
                                          Span<MLoop> loops,
@@ -310,13 +259,9 @@ void BM_mesh_bm_from_me(BMesh *bm, const Mesh *me, const struct BMeshFromMeshPar
     CustomData_bmesh_init_pool(&bm->ldata, me->totloop, BM_LOOP);
     CustomData_bmesh_init_pool(&bm->pdata, me->totpoly, BM_FACE);
   }
-  BM_mesh_cd_flag_apply(bm, me->cd_flag | (is_new ? 0 : BM_mesh_cd_flag_from_bmesh(bm)));
 
   /* Only copy these values over if the source mesh is flagged to be using them.
    * Even if `bm` has these layers, they may have been added from another mesh, when `!is_new`. */
-  const int cd_edge_crease_offset = (me->cd_flag & ME_CDFLAG_EDGE_CREASE) ?
-                                        CustomData_get_offset(&bm->edata, CD_CREASE) :
-                                        -1;
   const int cd_shape_key_offset = tot_shape_keys ? CustomData_get_offset(&bm->vdata, CD_SHAPEKEY) :
                                                    -1;
   const int cd_shape_keyindex_offset = is_new && (tot_shape_keys || params->add_key_index) ?
@@ -394,10 +339,6 @@ void BM_mesh_bm_from_me(BMesh *bm, const Mesh *me, const struct BMeshFromMeshPar
 
     /* Copy Custom Data */
     CustomData_to_bmesh_block(&me->edata, &bm->edata, i, &e->head.data, true);
-
-    if (cd_edge_crease_offset != -1) {
-      BM_ELEM_CD_SET_FLOAT(e, cd_edge_crease_offset, (float)medge[i].crease / 255.0f);
-    }
   }
   if (is_new) {
     bm->elem_index_dirty &= ~BM_EDGE; /* Added in order, clear dirty flag. */
@@ -957,7 +898,6 @@ void BM_mesh_bm_to_me(Main *bmain, BMesh *bm, Mesh *me, const struct BMeshToMesh
   BMIter iter;
   int i, j;
 
-  const int cd_edge_crease_offset = CustomData_get_offset(&bm->edata, CD_CREASE);
   const int cd_shape_keyindex_offset = CustomData_get_offset(&bm->vdata, CD_SHAPE_KEYINDEX);
 
   const int ototvert = me->totvert;
@@ -1006,8 +946,6 @@ void BM_mesh_bm_to_me(Main *bmain, BMesh *bm, Mesh *me, const struct BMeshToMesh
    * different than the BMesh's. */
   BKE_mesh_clear_derived_normals(me);
 
-  me->cd_flag = BM_mesh_cd_flag_from_bmesh(bm);
-
   i = 0;
   BM_ITER_MESH (v, &iter, bm, BM_VERTS_OF_MESH) {
     copy_v3_v3(mvert[i].co, v->co);
@@ -1045,10 +983,6 @@ void BM_mesh_bm_to_me(Main *bmain, BMesh *bm, Mesh *me, const struct BMeshToMesh
 
     bmesh_quick_edgedraw_flag(&medge[i], e);
 
-    if (cd_edge_crease_offset != -1) {
-      medge[i].crease = BM_ELEM_CD_GET_FLOAT_AS_UCHAR(e, cd_edge_crease_offset);
-    }
-
     i++;
     BM_CHECK_ELEMENT(e);
   }
@@ -1258,8 +1192,6 @@ void BM_mesh_bm_to_me_for_eval(BMesh *bm, Mesh *me, const CustomData_MeshMasks *
   MLoop *mloop = loops.data();
   unsigned int i, j;
 
-  const int cd_edge_crease_offset = CustomData_get_offset(&bm->edata, CD_CREASE);
-
   /* Clear normals on the mesh completely, since the original vertex and polygon count might be
    * different than the BMesh's. */
   BKE_mesh_clear_derived_normals(me);
@@ -1315,10 +1247,6 @@ void BM_mesh_bm_to_me_for_eval(BMesh *bm, Mesh *me, const CustomData_MeshMasks *
       }
     }
 
-    if (cd_edge_crease_offset != -1) {
-      med->crease = BM_ELEM_CD_GET_FLOAT_AS_UCHAR(eed, cd_edge_crease_offset);
-    }
-
     CustomData_from_bmesh_block(&bm->edata, &me->edata, eed->head.data, i);
   }
   bm->elem_index_dirty &= ~BM_EDGE;
@@ -1374,6 +1302,4 @@ void BM_mesh_bm_to_me_for_eval(BMesh *bm, Mesh *me, const CustomData_MeshMasks *
   hide_vert_attribute.finish();
   hide_edge_attribute.finish();
   hide_poly_attribute.finish();
-
-  me->cd_flag = BM_mesh_cd_flag_from_bmesh(bm);
 }
diff --git a/source/blender/bmesh/intern/bmesh_mesh_convert.h b/source/blender/bmesh/intern/bmesh_mesh_convert.h
index a04136afc1d..3f8e9e3dfef 100644
--- a/source/blender/bmesh/intern/bmesh_mesh_convert.h
+++ b/source/blender/bmesh/intern/bmesh_mesh_convert.h
@@ -13,10 +13,6 @@ struct CustomData_MeshMasks;
 struct Main;
 struct Mesh;
 
-void BM_mesh_cd_flag_ensure(BMesh *bm, struct Mesh *mesh, char cd_flag);
-void BM_mesh_cd_flag_apply(BMesh *bm, char cd_flag);
-char BM_mesh_cd_flag_from_bmesh(BMesh *bm);
-
 struct BMeshFromMeshParams {
   bool calc_face_normal;
   bool calc_vert_normal;