Blender Git Loki

Merge branch 'master' into blender2.8

Cleanup: long lines

Merge branch 'master' into blender2.8

Cycles: add roughness baking support, using squared roughness convention.

Cycles: switch to squared roughness convention for all nodes.

This was already done for the Principled BSDF to be compatible with typical
baked roughness maps in PBR workflows.

Merge branch 'master' into blender2.8

Code cleanup: fix compiler warning.

Fix T54279: viewport update bug with volume meshes.

Meshes without vertex normals were not handled correctly.

Code refactor: reduce number of loops over meshes.

Fix T54278: volume artifacts with small density and color after recent changes.

Fix T54269: saved EXR file files unreadable some editors in Blender.

Don't write the multichannel metadata when there is only a single layer,
and don't unnecessarily consider single layer images with Blender metadata
as multi layer.

Code cleanup: use spaces for aligned indentation.

Cycles: support arbitrary number of motion blur steps for objects.

Cycles: support arbitrary number of motion blur steps for cameras.

Code refactor: motion blur cleanups, preparing for next commit.

Code refactor: don't expose UpdateObjectTransformState in header.

Code refactor: make Transform always affine, dropping last row.

This save a little memory and copying in the kernel by storing only a 4x3
matrix instead of a 4x4 matrix. We already did this in a few places, and
those don't need to be special exceptions anymore now.

Code refactor: add DecomposedTransform.

This is in preparation of making Transform affine only, and also gives us
a little extra type safety so we don't accidentally treat it as a regular
4x4 matrix.

Code refactor: add ProjectionTransform separate from regular Transform.

This is in preparation of making Transform affine only.

Code refactor: avoid motion transform copy, remove unused curved code.

The purpose of the previous code refactoring is to make the code more readable,
but combined with this change benchmarks also render about 2-3% faster with an
NVIDIA Titan Xp.