Depsgraph: Add query methods to identify all the ID's that a given datablock depends on

This commit adds a new method, DEG_foreach_ancestor_ID()
to accompany the existing DEG_foreach_descendent_ID().

It can be used to help print/collect all the ID's that
a given ID block depends on (i.e. all the datablocks that
need to be evaluated before the datablock of interest can
be evaluated)

1 files changed, 3 insertions, 0 deletions

diff --git a/source/blender/depsgraph/DEG_depsgraph_query.h b/source/blender/depsgraph/DEG_depsgraph_query.h
index 1c4e11d1197..41650769fcf 100644
--- a/source/blender/depsgraph/DEG_depsgraph_query.h
+++ b/source/blender/depsgraph/DEG_depsgraph_query.h
@@ -197,6 +197,9 @@ typedef void (*DEGForeachIDCallback)(ID *id, void *user_data);
 /* NOTE: Modifies runtime flags in depsgraph nodes, so can not be used in
  * parallel. Keep an eye on that!
  */
+void DEG_foreach_ancestor_ID(const Depsgraph *depsgraph,
+                             const ID *id,
+                             DEGForeachIDCallback callback, void *user_data);
 void DEG_foreach_dependent_ID(const Depsgraph *depsgraph,
                               const ID *id,
                               DEGForeachIDCallback callback, void *user_data);