Blender Git Loki

Alembic import: fixed memory management for CoW copies of CacheFile blocks

When a CacheFile datablock is copied to an in-main datablock, it means that
the new copy should be independent of the old copy. In this case certain
properties are reset/duplicated. When it is copied to a no-main datablock,
we assume this is a copy-on-write copy that's used for evaluating things,
in which case the handle and object paths are referenced instead of
reset/ duplicated. This prevents us from re-opening the Alembic file every
time a new CoW copy is made.

The same approach is taken when freeing data (only when an in-main datablock
is freed do we actually free the data).

Alembic import: assign cache_file handle to original datablock

Cycles: Added a checkbox in Blender's GUI to turn
on/off the new light sampling method.

The checkbox can be found at the bottom of the sampling
section in the Render tab. The method is not used by
default.

Cycles: Implemented the SAOH splitting method

Previously the light bvh construction code used a simple method
to split a node into two child nodes based only on the bounding
box of the node. Now, it splits a node into two by looking at
the energy and direction of the lights inside the nodes and the
area of their bounding boxes.

Technical changes:
- Implemented orientation BVH build
- Added energy to each node based on emission
- Updated PDF calculations for lights when using the light BVH

Cleanup: getting rid of G.main.

Sometimes one needs a *lot* of changes for a single G.main... :/

Fix T55391: Anim render only shows scene state at current frame (no animation)

Studiolight: Segment when using float based matcaps

Reduce sparse grid memory usage and minor fixes.

Sparse grids originally padded out an image to dimensions divisible by
TILE_SIZE, which resulted in many empty voxels in large volumes. Now,
border tiles are taken into account when calculating voxel indexes.

Aside from that, made some other minor fixes throughout the files.

Depsgraph: Fix missing relations when camera has drivers

Depsgraph: Cleanup, make conditions more clear and less indented

Depsgraph: Don't optimize out collections used by duplication system

This makes evaluated objects to point to a non-evaluated collection,
which is already really bad. What is even more worse, objects in those
collections are not evaluated either.

Proper solution would be to implement visibility flag for nodes, which
will be set to 0 for transform/geometry components, but which will be
1 for copy-on-write components.

This way we will guarantee consistency of dependency graph.

For now this change is good enough and unlocks production.

Fixes T55375: Crash when changing visibility of instanced collection
Fixes T55357: Particle geometry crash

Depsgraph: Cleanup, indentation

Depsgraph: Cleanup, make conditions more clear and less indented

Alembic export: create render-evaluated depsgraph for exporting

Previously the context depsgraph was used, which (most likely) uses
viewport evaluation instead of render evaluation.

Randomization is (currently) only available for melanin

Merge branch 'master' into soc-2018-hair-shader

Week 4's merge: two formatting issues fixed

CMake: disable WITH_COMPILER_ASAN for CMAKE_BUILD_TYPE Release

Cleanup: redundant check

Merge branch 'blender2.8' into greasepencil-object

Merge branch 'master' into blender2.8