Merge branch 'greasepencil-object' into greasepencil-refactor

Merge branch 'master' into greasepencil-object

GPencil: New evaluation of derived frames and Filling calculation

As grease pencil was created before depgraph, it was using a custom solution to create derived data to apply modifiers on top. With the new refactor of the drawing engine, we need to have the runtime data at datablock (bGPdata) level to share between instances, but also we neeed to have separated eval data because different objects can use different modifiers (equals to actual mesh_eval logic). The old derived frame array solution is not valid anymore.

The initial idea was to make a full copy of the datablock in a separated eval copy, but testing this solution, it was very slow, so now, the full copy is only done once, and later, only the active frame data is updated (see note below).

In a future development, the ideal solution would calculate all frames at the same time and only copy again if something changes, but now this change is out of scope. I have been performing tests and with this "only active frame" copy,

Also, this solution simplifies several areas of the code, because now it's not necessary to deal with derived frame array, and just use datablock as is.

This update also includes the following:

* How the filling information is managed. Before, the triangulation data was created only during drawing process, and it was not saved. With the new engine, this information must be available always, so instead to calculate in drawing time, now the information is saved and generated or updated each time the stroke is modified. To have the filling information calculated improves FPS and simplify drawing and modifier evaluation code.

* Remove unused parameters related to old Filling calculation logic. This also simplifies the UI panels.

* Added simplify modifier options. This was removed, but after last changes it's good to have as before.

Differential Revision: https://developer.blender.org/D6597

Weight Paint: implement a red shade for bones with locked weights.

Blender supports locking vertex groups to prevent changes to the
weights. However, as mentioned in comments for D3837, it is hard
to use this because there is no interface for locking in 3D View.

This adds a red shade to bones that are associated with a locked
weight group during weight paint mode, as the first step to adding
such interface. The next step is adding a pie menu for lock/unlock.

Differential Revision: https://developer.blender.org/D6533

GPencil: Refactor: Speedup: Add drawcall merging of consecutive strokes

This reduces driver & DRW overhead when a lot of strokes are drawn with
the same material pool.

Merge branch 'greasepencil-refactor' into temp-gpencil-eval

Merge branch 'greasepencil-object' into greasepencil-refactor

Merge branch 'master' into greasepencil-object

Merge branch 'blender-v2.82-release'

Cleanup: factorize collection handling in libquery code.

Both actual Collection datablocks and the horrible master collection
should share the same code (there were already some differences,
although probably not critical, but some callbacks from
scene->master_collection did not have the 'not self' flag...).