Blender Git Loki

Volumes: use principled volume by default in volume object materials

This is mostly straightforward, but required some refactoring in Cycles to
ensure that the default volume material does not always turn on the volume
feature for GPU rendering.

GPencil: Remove old drawing from Interpolate operator

Now the drawing is done using the normal drawing engine and not the old drawing code.

Fluid: Optimization for fluid domain obstacle boundary handling

This fix should especially improve liquid obstacles boundaries, i.e. help with the problem of particles sticking to the surface.

Fluid: Hide Advanced cache options

The Manta script export should not be visible in the UI. At least not to normal users. The export feature is only useful for developers.

Merge branch 'undo-experiments' into undo-experiments-swap-reread-datablocks

Merge branch 'master' into undo-experiments

Readfile: refactor/factorize more handling of common ID data.

- Move handling of private ID data (nodetree and master_collection)
under generic ID code. This shortens code a bit, but mostly avoids having
to modify all type-specific callback functions if/when we have to add
generic processing to IDs there.

- Seriously factorize `expand_xxx` area, in the same way we were already
doing in `direct_link_xxx` and `lib_link_xxx` areas.

Note that this actually also fixes some bugs (at least, potential ones),
like e.g. missing call to expand_id() for our beloved 'private ID'
(nodetrees & co), in current master code...

Differential Revision: https://developer.blender.org/D6764

NodeTree: Add access to the address of an ID's nodetree pointer.

Merge branch 'master' into readfile_factorize_common_id_processing

Merge branch 'undo-experiments' into undo-experiments-swap-reread-datablocks

Conflicts:
source/blender/blenloader/intern/readfile.c

Merge branch 'master' into new-object-types

Merge branch 'blender-v2.82-release' into master

Cleanup: Interpolate operator

Replace loops and remove old unused code

Reference correct sha1s of submodules

OpenVDB: Fix IOError in try catch statement

Broader exception handling for OpenVDB IO errors.

Fluid: Fixed slow cache loading for smoke data

Cache files are currently loaded via the Manta Python API. With very big caches this can slow down the viewport playback. Especially smoke simulations, which just load grids and no meshes, can suffer from this. This fix solves this problem by directly loading the cache files from disk (no Python). This fix has been in the works for some time. The developer of this patch is ready to handle any potential fall-out of this patch quickly.

Merge branch 'readfile_factorize_common_id_processing' into undo-experiments

Merge branch 'master' into readfile_factorize_common_id_processing

store default value per CPPType

Readfile: refactor/factorize more handling of common ID data.

- Move handling of private ID data (nodetree and master_collection)
under generic ID code. This shortens code a bit, but mostly avoids having
to modify all type-specific callback functions if/when we have to add
generic processing to IDs there.

- Seriously factorize `expand_xxx` area, in the same way we were already
doing in `direct_link_xxx` and `lib_link_xxx` areas.

Differential Revision: https://developer.blender.org/D6764