Blender Git Loki

Drivers: add lerp and clamp functions to namespace.

Implementation of lerp without a function requires repeating one of
the arguments, which is not ideal. To avoid that, add a new function
to the driver namespace. In addition, provide a function for clamping
between 0 and 1 to support easy clamped lerp, and a smoothstep function
from GLSL that is somewhat related.

The function implementations are added to a new bl_math module.
As an aside, add the round function and two-argument log to the
pylike expression subset.

Differential Revision: https://developer.blender.org/D8205

Particles: initial object socket and emitter node support

Object sockets work now, but only the new Object Transforms and the
Particle Mesh Emitter node use it. The emitter does not actually
use the mesh surface yet. Instead, new particles are just emitted around
the origin of the object.

Internally, handles to object data blocks are passed around in the network,
instead of raw object pointers. Using handles has a couple of benefits:
* The caller of the function has control over which handles can be resolved
and therefore limit access to specific data. The set of data blocks that
is accessed by a node tree should be known statically. This is necessary
for a proper integration with the dependency graph.
* When the pointer to an object changes (e.g. after restarting Blender),
all handles are still valid.
* When an object is deleted, the handle is invalidated without causing crashes.
* The handle is just an integer that can be stored per particle and can be cached easily.

The mapping between handles and their corresponding data blocks is
stored in the Simulation data block.

UI: Adjust Multiresolution Modifier Layout

Adjusting the layout for this modifier is the final part of the modifier UI
project for 2.90. This layout exposes the most important information,
the levels and subdivision controls, by default, putting other contols
in collapsed subpanels.

Note that there is empty space for the "Delete Lower" button
that is still planned for 2.90. And there will also eventually be more
items added to the "Shape" panel, maybe for 2.90.

Differential Revision: https://developer.blender.org/D8187

UI: Use consistent layout for custom operator UI

Operators are one of the last places in Blender to use older UI designs
that don't fit in with recent style conventions. This commit updates
these custom operator UI callbacks for consistency and clarity.

Some of the code is also simplified a lot. Some of the older operator layouts
were much more complex (in terms of code) than they needed to be.

See the differential revision for a before and after screenshot
of each operator.

Differential Revision: https://developer.blender.org/D8326

UI: Add an outer boundary for edge panning, use in outliner

Currently if you drag and drop an item from the outliner elsewhere in
the Blender window, the outliner will scroll the entire time, even if the
mouse is far away. This commit adds optional behavior for the edge pan
operator that makes it only act if the mouse is close enough to the region.

Differential Revision: https://developer.blender.org/D8193

Cleanup: Comments.

Fix (unreported) broken code in recent override operator enhancements.

When overriding a whole linked collection from a single object in
3DView, said 'reference' object would be removed by code. We only want
that behavior when overriding from an instanciating Empty.

Fix T78994: Clear selected pose doesn't work without animation

It looks like the code left this as a todo, but the basic solution is to
add an extra parameter to BKE_bose_rest to check whether bones
are selected before reseting them.

I also corrected the operator description which said it acted on only
selected bones even when there is an option to turn that off. The
"act on selected" is generally implied for Blender's operators anyway.

Differential Revision: https://developer.blender.org/D8319

Fluid: Updated Mantaflow source files

Updated files include fixes for the mesh IO - read/write success was not propagated.

Cleanup: CodeQuality: Replace OB_DRAWXRAY by OB_DRAW_IN_FRONT

This is to match the option name and to avoid confusion with
workbench xray mode.

Fluid: Cleanup unused variables

Tests: IO, fixed a memory leak in the USDHierarchyIteratorTest

No functional changes to Blender.

Cleanup: IO, renamed `delete_object_writer()` ? `release_writer()`

The function is called for all writers, not just 'object' writers.
Furthermore, it's called by the function `release_writers()`, so now the
name is consistent with that as well.

No functional changes.

Tests: fix link errors when USD and Alembic are disabled

The unit tests for `bf_io_common` didn't actually link against
`bf_io_common`, so when both USD and Alembic were disabled, nothing
would link against that library and building the tests would fail.

Fix T79112: Redo shrink/fatten uses negative values

The numbers in the redo panel were negated compared to the value
entered while transforming.

Fix T78867: Crash related to viewing video files

Any time FFmpeg was used to get a picture Blender would crash
when FFmpeg 4.3 is used. This affects thumbnails, VSE, Clip Editor.

Caused by a bug in FFmpeg which lead to crashes when unaligned
buffer was passed to sws_scale(). It got fixed later on in FFmpeg,
but for portability and compatibility reasons still nice to avoid
crash, especially since it's not so difficult to do.

FFmpeg ticked number is #8747
The FFmpeg Git hash with the fix: ba3e771a42c2

Differential Revision: https://developer.blender.org/D8355

GPencil: Reorganize Snap pie menu

Put the options in the same position of meshes.

related to T79094

Cleanup: `layer_collection_sync`: use `LISTBASE_FOREACH_MUTABLE`.

Cleanup: `layer_collection_sync`: use proper naming.

Previous ones were extremely confusing and innacurate (probably
inherited from older versions of scene collections?).

Also, use named fields in struct initialization, much much safer and
cleaner than anonymous, positionned-based thing.

Fix T72621: Transform object origin support for grease-pencil

Added support for transforming only origins with greasepencil objects.

The new functions is based on BKE_gpencil_transform. That is why there is FIXME statements in there.

Reviewed By: Campbell, Antonio

Differential Revision: https://developer.blender.org/D8303