Alembic Procedural: only subdivide if subsurf modifier is present

As subdivision objects are first class citizens in Alembic, to
differentiate them with non-subdivided polygon meshes, the Alembic
Procedural automatically sets up subdivision properties on the generated
Cycles Mesh.

However, for real-time playback subdivision is far too slow, so this
modifies the detection of a MeshSeqCache modifier used to activate the
procedural to allow for a Subsurf modifier right after the cache one. If
present, the procedural will tag the object for subdivision, if absent, the
object will be treated as a regular mesh.

This is a temporary measure for until subdivision surface settings are part
of the Mesh datablock (see T68891).

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D11162

1 files changed, 2 insertions, 2 deletions

diff --git a/intern/cycles/blender/blender_mesh.cpp b/intern/cycles/blender/blender_mesh.cpp
index d1042277183..ebba6981502 100644
--- a/intern/cycles/blender/blender_mesh.cpp
+++ b/intern/cycles/blender/blender_mesh.cpp
@@ -1078,7 +1078,7 @@ static void sync_mesh_cached_velocities(BL::Object &b_ob, Scene *scene, Mesh *me
     return;
   }
 
-  BL::MeshSequenceCacheModifier b_mesh_cache = object_mesh_cache_find(b_ob, true);
+  BL::MeshSequenceCacheModifier b_mesh_cache = object_mesh_cache_find(b_ob, true, nullptr);
 
   if (!b_mesh_cache) {
     return;
@@ -1241,7 +1241,7 @@ void BlenderSync::sync_mesh_motion(BL::Depsgraph b_depsgraph,
   }
 
   /* Cached motion blur already exported. */
-  BL::MeshSequenceCacheModifier mesh_cache = object_mesh_cache_find(b_ob, true);
+  BL::MeshSequenceCacheModifier mesh_cache = object_mesh_cache_find(b_ob, true, nullptr);
   if (mesh_cache) {
     return;
   }