Partially revert 41216d5ad4
Some of this code had comments to be left as is for readability,
or comment the code should be kept.
Other functions were only for debugging.
This is a bug experienced by animators in the Blender Studio that developers
have been trying to fix for a /long/ time.
What happens is that partial file writing extracts the needed datablocks from
the main list of datablocks into a smaller one. Afterwards they are added back
to the main list, but in some cases not exactly in the same order.
There is file path remapping code that depends on the datablocks being in
exactly the same order as before, and when this was not the case filepaths
would get swapped between datablocks
The reason datablocks are not restored in the same order is because the sorting
of datablocks by name is a) case insensitive and b) undefined if there are
multiple datablocks with the same name from different libraries. This should
be made well defined, but the fix in this commit is simpler.
The way animators ran into this bug is that they use the Copy Attributes addon
a lot, which has as the first item in the menu Copy Selection to Buffer. In
some cases this would be clicked accidentally when menu is near the edge of the
window, breaking the library paths which would only be noticed a much later on
file save and reload.
The way this bug was finally tracked down is that it was suspected that the
undo system was the cause, and so Bastien added library validation for undo.
When Hjalti then did undo and noticed the error, he remembered accidentally
clicking Copy Selection to Buffer just before, and we could finally reproduce
the bug.
Having an invisible gizmo caused event handling problems (see: T56603).
This is hard to avoid since gizmos are similar to buttons in the way
they have priority over the regular keymap.
Transform events use tweak so events to fall though to the general
view 3d keymap (for cursor placement for eg).
- Use smooth normals to displace in Above Surface mode.
- Add an option to align an axis to the normal in the constraint.
I've seen people request the alignment feature, and it seems useful.
For the actual aligning I use the damped track logic.
In order to conveniently keep mesh data needed for normal
computation together, a new data structure is introduced.
Reviewers: mont29
Differential Revision: https://developer.blender.org/D3762
There are serious suspicions that weird corruptions faced by studio
artists may happen in undo/redo code, so let's see whether that's the
case.
With this, and when --debug-io arg is passed on startup, the whole lib
data are checked at every undo. This makes undo slower (from two to
three times slower), but it could help us spot better what happens...
This was re-enabled because it made copy-on-write bugs hard to
track down.
Since copy-on-write implementation has been simplified
this isn't a problem anymore.
