Fix T95843: Invalid mesh runtime data after sculpt undov3.1.0

When the geometry of the sculpt mesh was replaced when restoring from
a full undo step, the runtime data was not cleared (including any
normals, triangulation data, or any other cached derived data).
In the report, only the invalid normals were observed.

The fix is to simply clear these caches. Later they will be reallocated
and recalculated if necessary. Since the whole mesh replaced here
anyway, this should be a safe fix.

Differential Revision: https://developer.blender.org/D14282

1 files changed, 3 insertions, 0 deletions

diff --git a/source/blender/editors/sculpt_paint/sculpt_undo.c b/source/blender/editors/sculpt_paint/sculpt_undo.c
index 8819496c168..f740f38fdc6 100644
--- a/source/blender/editors/sculpt_paint/sculpt_undo.c
+++ b/source/blender/editors/sculpt_paint/sculpt_undo.c
@@ -47,6 +47,7 @@
 #include "BKE_key.h"
 #include "BKE_main.h"
 #include "BKE_mesh.h"
+#include "BKE_mesh_runtime.h"
 #include "BKE_multires.h"
 #include "BKE_object.h"
 #include "BKE_paint.h"
@@ -547,6 +548,8 @@ static void sculpt_undo_geometry_restore_data(SculptUndoNodeGeometry *geometry,
       &geometry->pdata, &mesh->pdata, CD_MASK_MESH.pmask, CD_DUPLICATE, geometry->totpoly);
 
   BKE_mesh_update_customdata_pointers(mesh, false);
+
+  BKE_mesh_runtime_clear_cache(mesh);
 }
 
 static void sculpt_undo_geometry_free_data(SculptUndoNodeGeometry *geometry)