Blender Git Loki

Cycles: Clamp Sky Texture altitude to avoid numerical issues

Differential Revision: https://developer.blender.org/D8091

Cycles: Account for Sky Texture mapping in the sun sampling code

Differential Revision: https://developer.blender.org/D8091

Cycles: Change precomputed Sky Texture mapping to prioritize the horizon

Differential Revision: https://developer.blender.org/D8091

Cycles: Add control for sun intensity in Sky Texture and change altitude to km

Differential Revision: https://developer.blender.org/D8091

Cycles: Add versioning code for the new Sky Texture model

Differential Revision: https://developer.blender.org/D8091

Cycles: Remove Vector input on Sky texture when using the included sun

When using the sun, we need to sun sampling logic to avoid excessive
sampling map resolution, but that logic assumes that the Vector input
comes from the view direction.
That is the case in the vast majority of cases anyways, so the easiest
solution is to just remove the input for that case.

Differential Revision: https://developer.blender.org/D8091

Cycles: Remove limits on the Sky texture's sun rotation

For animation/driver purposes, being able to go outside of the 0-360
range makes things easier.

Differential Revision: https://developer.blender.org/D8091

macOS: Fixed libpng build on arm64 without requiring a patch.

A large refactor of newboolean to perpare for performance tuning.

Many changes aimed at, broadly, more sharing and less copying;
and having coordinates stored simultaneously in double and multiprecision,
as that will be needed for floating predicate filtering.
Biggest change is that faces are represented by arrays of pointers to
Verts instead of as integer indices into a vertex array.

clang format, style: use {} initialization, nullptr.

Make custom B/Mesh deleters for clean syntax

Merge branch 'mac_arm64' of git.blender.org:blender into mac_arm64

deps: Cleanup.

Fix build error

Merge local branch for importer into soc-2020-io-performance

Merge branch 'master' into soc-2020-io-performance

Use custom creators and deleters for Mesh and BMesh

Avoid freeing meshes allocated by Guarded allocated by unique_ptr

Mark OBJRawObject const in add_object_to_parent.

Cleanup: unused debug variable

Particles: initial support for forces in simulation node trees

The force node can now be used to control the behavior of particles.
Forces can access particles attributes. Currently, there are three attributes:
`Position` (vector), `Velocity` (vector) and `ID` (integer).

Supported nodes are: Math, Vector Math, Separate Vector, Combine Vector and Value.

Next, I'll have to split `simulation.cc` into multiple files and move
some stuff out of blenkernel into another folder.