Blender Git Loki

Pose Library: don't crash `POSELIB_OT_blend_pose` outside asset browser

Cleanup: update TODO

No functional changes.

Pose Library: blend quaternions properly, instead of LERPing them

This also removes the `bool flush_to_original` argument, as this flushing
is not required for the pose library (poses are always applied to the
original, and not to evaluated copies).

Cleanup: remove unnecessary `ATTR_FALLTHROUGH`

`ATTR_FALLTHROUGH` is only necessary when there is actually code inside
the falling-through `case`.

No functional changes.

Explicitly consider hidden bones as not selected

Cleanup: pose library, remove unused includes

No functional changes.

Pose blending: also apply rounding to floats

My code for interpolating booleans basically performed the same function
as the rounding for ints and enums. Now the code is the same, too.

No functional changes

Add operator `POSELIB_OT_blend_pose` for interactive pose blending

The operator doesn't blend yet, but it does allow temporarily applying the
pose, switching between the original and the given pose with Tab, applying
the pose with Enter/LeftClick, and cancelling with Esc/RightClick.

Rough implementation for temp-loading poses from C

The code needs some cleanup, as the temp-loading of asset datablocks needs
to be separated from the pose library code.

Cleanup: remove unused code and rename variables/fields

No functional changes.

Pose library: add simple blending of pose Action onto current pose

Naieve blending of the pose Action onto the current pose. This performs
linear blending (LERP) per FCurve. This is not suitable for rotations, so
it's probably better to do proper matrix interpolation for loc/rot/scale.
However, for other properties, the current LERP will be necessary anyway.

Pose library: Use scrollwheel to set the blend factor

This is not the final UI, but gives a way to at least set it to some value.

Do proper updates when local asset data changes

Makes sure the asset list is updated and redrawn correctly an local asset data
changes: Creating assets, removing assets, clearing assets, undo/redo, reading
files (with and without UI), parallel reading of asset data from files, ...

For redraws there now is a listener callback in the uiList type (C only) that
asks the asset lists if it needs a redraw after a given notifier. For the case
of asset data-block removal there is a ID remapping function in the asset list
now (just tags the list for a complete re-read). File reading, undo, redo and
the "Mark Asset"/"Clear Asset" operators explicitly tag asset lists showing
main data as dirty (via the global asset storage).

Merge branch 'master' into ui-asset-view-template

Merge branch 'master' into ui-asset-view-template

Support passing ID type filter to the template

The ID type filter can be set as follows:
```
template_asset_view(..., filter_id_types={'filter_material', 'filter_object'})
```

I would have prefered if you could just create a
`bpy.types.AssetFilterSettings` object, fill that and pass it to the
template. But that doesn't seem possible right now without more complex
BPY additions.
Also, newer ID types (hair, point cloud, volume and simulation IDs) do
not support filtering, because their filtering flags exceed 32, meaning
we have to store them in 64 bit integers which RNA doesn't support for
enum properties...

Merge branch 'master' into ui-asset-view-template

Fix items not showing up if the preview is missing

No reason to skip adding the UI elements just because the preview is missing.
We can still show the text and allow dragging. Also makes it feel more
interactive while the previews load in a background thread.

Add own button/widget type for the asset previews

The new button type (UI_BTYPE_PREVIEW_TILE) shows the items similar to
the Asset Browser, or the File Browser in thumbnail display mode. That
is, previews bigger than normal buttons, with the name drawn centered
below it.

Would be nice if the File/Asset Browser and preview templates could
adopt that new button type, so that there's no ad-hoc drawing for these
anymore. That's for a future cleanup though.

Properly support mouse-selecting items in the asset view list

This was very glitchy before and just didn't work in most cases. The mouse
press event was simply caught by the preview icon button and didn't make its
way to the underlying list-row button.