Fix: Joining armatures loses drivers

Currently, when joining two armatures, the drivers of the armatures being merged
in are lost. This commit introduces a new AnimData API function for merging
animation data into another AnimData block.

NOTE:
* For now, this only copies the drivers over. As a result, manual effort will
  still be needed to go through and fix the drivers.

  I am working on automating that process, but it's more important that the
  drivers don't have to be created from scratch for now (since this is needed
  for the Goosberry rigging work).

1 files changed, 14 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_animsys.h b/source/blender/blenkernel/BKE_animsys.h
index a5109acfa56..24abd114a90 100644
--- a/source/blender/blenkernel/BKE_animsys.h
+++ b/source/blender/blenkernel/BKE_animsys.h
@@ -73,6 +73,20 @@ bool BKE_copy_animdata_id(struct ID *id_to, struct ID *id_from, const bool do_ac
 /* Copy AnimData Actions */
 void BKE_copy_animdata_id_action(struct ID *id);
 
+/* Merge copies of data from source AnimData block */
+typedef enum eAnimData_MergeCopy_Modes {
+	/* Keep destination action */
+	ADT_MERGECOPY_KEEP_DST = 0,
+	
+	/* Use src action (make a new copy) */
+	ADT_MERGECOPY_SRC_COPY = 1,
+	
+	/* Use src action (but just reference the existing version) */
+	ADT_MERGECOPY_SRC_REF  = 2
+} eAnimData_MergeCopy_Modes;
+
+void BKE_animdata_merge_copy(struct ID *dst_id, struct ID *src_id, eAnimData_MergeCopy_Modes action_mode, bool fix_drivers);
+
 /* Make Local */
 void BKE_animdata_make_local(struct AnimData *adt);