Blender Git Loki

Cycles: Use XDG's .cache folder for cached kernels

Basically just moves cached kernels from ~/.config/blender/BLENDER_VERSION to
~/.cache/cycles/kernels. This has following benefits:

- Follows XDG specification more closely,
not as if it's totally crucial or measurable by users, but still nice.

- Prevents unexpected sizes of config folder, makes disk space used in more
predictable for users way.

- Allows to share kernels across multiple Blender versions,
which makes it easier debugging at the times close to release.

- "Copy Previous Settings" operator will no longer be copying possibly
gigabytes of cached kernels, which used to lead to really nast disk usage
and annoying delays of copying settings.

- In the future we can have some smart logic to clear old unused cached
kernels.

Currently only done for Linux and OSX. Windows still follows old "cache"
folder logic, but it's not really important for now because we don't
support kernel compilation on this platform yet.

Reviewers: dingto, juicyfruit, brecht

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D2197

Cycles: Add overall timing log to SVNShaderManager

Cycles: Deduplicate QBVH node packing across BVH build and refit

Cycles: Don't run full shader evaluation for constant emission lamps

Most of the time, Lamps in Cycles are just a constant emission closure, no texturing etc. Therefore, running a full shader evaluation is wasteful.
To avoid that, Cycles now detects these constant emission shaders and stores their value in the lamp data along with a flag in the shader.
Then, at runtime, if this flag is set, the lamp code just uses this value and only runs the full shader evaluation if it is neccessary.

In scenes with a lot of lamps and with "Sample all direct/indirect" enabled, this saves up to 20% of rendering time in my tests.

Reviewers: #cycles

Differential Revision: https://developer.blender.org/D2193

Cycles: Revert cleanup commit, will make it easier to cherry-pick

Cycles/Render API: Get rid of Render Pass flags and port Denoising passes to the new system

This also means that the temporary uint64_t passflag hack is removed now.

Clean-up some collision data allocation stuff

Self collision pointer logic has been simplified and allocations
reduced, as it only collides with one object (self).

Also, allocation size for all collisions has been reduced to 1/4,
because it was allocating extra space for deprecated stuff.

Implement self col groups for new self col system

Remove edgeset stuff (no longer used)

Merge branch 'master' into cycles_split_kernel

Remove unused selfbvh stuff

Removed Batch storage
Also lots of renaming
Small visual tweaks
Material Settings Struct is now shared by Scene and material

Move use_normal to col object settings (was in cloth settings)

Use proper friction property for self col and redesign col UI

Separate self collision distance from object collision distance

Remove self collision quality (integrated with object collision)

Self collisions are now impulse based, and utilize the same solver as
the object collisions. Having separate quality controls would cause
issues when self and object collisions occur simultaneously.

Remove old repulsion stuff

Repulsions were long unused, and are now more obsolete than ever, with
the more stable collision response.

Remove unused functions in collision.c

I hereby declare layers syncing fully implemented!

curve convert and mesh separation working