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

1 files changed, 1 insertions, 34 deletions

diff --git a/source/blender/blenkernel/intern/data_transfer.c b/source/blender/blenkernel/intern/data_transfer.c
index 6c7715c625e..f2732cea91a 100644
--- a/source/blender/blenkernel/intern/data_transfer.c
+++ b/source/blender/blenkernel/intern/data_transfer.c
@@ -199,7 +199,7 @@ int BKE_object_data_transfer_dttype_to_cdtype(const int dtdata_type)
     case DT_TYPE_SEAM:
       return CD_FAKE_SEAM;
     case DT_TYPE_CREASE:
-      return CD_FAKE_CREASE;
+      return CD_CREASE;
     case DT_TYPE_BWEIGHT_EDGE:
       return CD_BWEIGHT;
     case DT_TYPE_FREESTYLE_EDGE:
@@ -981,39 +981,6 @@ static bool data_transfer_layersmapping_generate(ListBase *r_map,
       }
       return true;
     }
-    if (cddata_type == CD_FAKE_CREASE) {
-      const size_t elem_size = sizeof(*((MEdge *)NULL));
-      const size_t data_size = sizeof(((MEdge *)NULL)->crease);
-      const size_t data_offset = offsetof(MEdge, crease);
-      const uint64_t data_flag = 0;
-
-      if (!(me_src->cd_flag & ME_CDFLAG_EDGE_CREASE)) {
-        if (use_delete) {
-          me_dst->cd_flag &= ~ME_CDFLAG_EDGE_CREASE;
-        }
-        return true;
-      }
-      me_dst->cd_flag |= ME_CDFLAG_EDGE_CREASE;
-      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);