Fix assert in original modifiers pointer update function

The issue was happening with a specific file where the ID management
code was not fully copying all modifiers because of the extra check
in the `BKE_object_support_modifier_type_check()`.

While it is arguable that copy-on-write should be a 1:1 copy there is
no real need to maintain the per-modifier pointer to its original.
Use its SessionUUID to perform lookup in the original datablock.

Downside of this approach is that it is a linear lookup instead of
direct pointer access, but the upside is that there is less pointers
to manage and that the file with unsupported modifiers does behave
correct without any asserts.

Differential Revision: https://developer.blender.org/D13993

1 files changed, 2 insertions, 5 deletions

diff --git a/source/blender/makesdna/DNA_modifier_types.h b/source/blender/makesdna/DNA_modifier_types.h
index 1d0796bda8b..8e38d52a4d7 100644
--- a/source/blender/makesdna/DNA_modifier_types.h
+++ b/source/blender/makesdna/DNA_modifier_types.h
@@ -128,15 +128,11 @@ typedef struct ModifierData {
 
   char *error;
 
-  /** Pointer to a #ModifierData in the original domain. */
-  struct ModifierData *orig_modifier_data;
-
   /** Runtime field which contains unique identifier of the modifier. */
   SessionUUID session_uuid;
 
   /** Runtime field which contains runtime data which is specific to a modifier type. */
   void *runtime;
-  void *_pad1;
 } ModifierData;
 
 typedef enum {
@@ -1012,7 +1008,8 @@ typedef struct MeshDeformModifierData {
   float *bindcos;
 
   /* runtime */
-  void (*bindfunc)(struct MeshDeformModifierData *mmd,
+  void (*bindfunc)(struct Object *object,
+                   struct MeshDeformModifierData *mmd,
                    struct Mesh *cagemesh,
                    float *vertexcos,
                    int totvert,