[Bf-blender-cvs] [745851e26b9] blender-v3.4-release: Fix T102772: Propagate edge creases in subdivision surface modifier

[Hans Goudey]

Commit: 745851e26b9f30693a9d09ca95f0d734bbcd25bc
Author: Hans Goudey
Date:   Mon Nov 28 14:06:18 2022 -0600
Branches: blender-v3.4-release
https://developer.blender.org/rB745851e26b9f30693a9d09ca95f0d734bbcd25bc

Fix T102772: Propagate edge creases in subdivision surface modifier

Before rBa8a454287a27, edge creases were copied to the result mesh as
part of `MEdge`. Now they are stored in a separate `CD_CREASE` layer,
which I mistakenly disabled for interpolation. However, to maintain
the geometry node uses a field input, remove the interpolated attribute
there.

===================================================================

M	source/blender/blenkernel/intern/subdiv_mesh.cc
M	source/blender/nodes/geometry/nodes/node_geo_subdivision_surface.cc

===================================================================

diff --git a/source/blender/blenkernel/intern/subdiv_mesh.cc b/source/blender/blenkernel/intern/subdiv_mesh.cc
index 3b97c1f5e68..5de78cdfe91 100644
--- a/source/blender/blenkernel/intern/subdiv_mesh.cc
+++ b/source/blender/blenkernel/intern/subdiv_mesh.cc
@@ -520,8 +520,10 @@ static bool subdiv_mesh_topology_info(const SubdivForeachContext *foreach_contex
    * so don't try to preserve it and use memory. Crease values should also not be interpolated. */
   CustomData_MeshMasks mask = CD_MASK_EVERYTHING;
   mask.lmask &= ~CD_MASK_MULTIRES_GRIDS;
+  /* Propagate edge creases so they can be used in another subdivision modifier (maintaining
+   * existing behavior), but don't propagate vertex creases to avoid extra work when the result
+   * isn't useful anyway. */
   mask.vmask &= ~CD_MASK_CREASE;
-  mask.emask &= ~CD_MASK_CREASE;
 
   SubdivMeshContext *subdiv_context = static_cast<SubdivMeshContext *>(foreach_context->user_data);
   subdiv_context->subdiv_mesh = BKE_mesh_new_nomain_from_template_ex(
@@ -791,7 +793,6 @@ static void subdiv_copy_edge_data(SubdivMeshContext *ctx,
 {
   const int subdiv_edge_index = subdiv_edge - ctx->subdiv_edges;
   if (coarse_edge == nullptr) {
-    /* TODO: Ensure crease layer isn't copied to result. */
     subdiv_edge->flag = 0;
     if (!ctx->settings->use_optimal_display) {
       subdiv_edge->flag |= ME_EDGERENDER;
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 2e6ad02bfd5..e0afae76419 100644
--- a/source/blender/nodes/geometry/nodes/node_geo_subdivision_surface.cc
+++ b/source/blender/nodes/geometry/nodes/node_geo_subdivision_surface.cc
@@ -170,6 +170,13 @@ static void node_geo_exec(GeoNodeExecParams params)
 
     Mesh *mesh_out = BKE_subdiv_to_mesh(subdiv, &mesh_settings, &mesh);
 
+    if (use_creases) {
+      /* Remove the layer in case it was created by the node from the field input. The fact
+       * that this node uses #CD_CREASE to input creases to the subvision code is meant to be
+       * an implementation detail ideally. */
+      CustomData_free_layers(&mesh_out->edata, CD_CREASE, mesh_out->totedge);
+    }
+
     geometry_set.replace_mesh(mesh_out);
 
     BKE_subdiv_free(subdiv);