Blender Git Commit Log

undoexp: better handling of recalc flags in undo case.

Fixes the 'object that not update its position when undoing the very
first undo step' issue.

Just like with the 'unchanged' detection, when going backward, i.e.
actual undo from n to n-1 stages, the 'recalc' flag stored in ID is not
that useful, as it actually marks the updates needed from n-2 to n-1 stages.

So we need a way to get 'future' recacl flags, i.e. the last recalc
flags used by the last despgraph update, for the current ID, and set
them into the newly read ID's racalc flags.

Note that am not sure how strong this approach is, it is relatively
simple, but may require some more involved handling (like accumulating
all flags used in-between two undo steps storage, or something
similar?).