Blender Git Loki

Cleanup: Get rid of remaining 'BKE_<id>_unlink()' functions, no more used anyway.

Cleanup: get rid of BKE_text_unlink(), replace by usage of generic BKE_libblock_... API.

Cleanup: remove RNA's `ID.destroy()` function.

We already have Main's ID lists' `remove()` function, better not do the same thing
in two different places!

Cleanup/refactor RNA IDs' `remove` functions.

Those (one per ID type!) were uselessly duplicated, and badly inconsistent
(some types were actually unlinking before deletion, others were only working if already unlinked!).

Now we use same func and same API for all types, by default deletion is performed only if ID is no more used,
set `do_unlink` parameter to True to always delete ID even if still in use.
Only exception now is with Scene, since we always want to keep at least one!

Note that this will change default behavior of some types (since unlinking is never done anymore by default).

CMake: exclude gitignore & arcconfig for addons

These files were included in releases

Cleanup: remove bad-level call

GPU: move select index code out of WM

This avoids bad-level calls.

Exclude obsolete static pythonlibs from install

Fix T48732, OpenCL compile failure after Multiscatter GGX commit.

Use OpenCL "all" builtin type for conversion, according to OpenCL 1.1 spec 6.3e.

Fix T48723: Curve bevel creates invalid geometry

Cleanup: use BLI_bitmap for bevel-split

BMesh: avoid redundant calculations comparing angles

Fix T48725: UI message typo.

Fix T48716: Knife cut creates inverted normals

In the case of having 3+ boundary edges, we need to find the best.

Cleanup: use return argument prefix

BKE_blender: Add own atexit functions

Runs before guarded-alloc leaks print.

Avoid memory leaks on exit during argument parsing

Exiting Blender during argument parsing would leak memory
(tests, documentation generation, utilities).

While harmless, it hides real leaks which should be resolved.

Cycles: Add multi-scattering, energy-conserving GGX as an option to the Glossy, Anisotropic and Glass BSDFs

This commit adds a new distribution to the Glossy, Anisotropic and Glass BSDFs that implements the
multiple-scattering microfacet model described in the paper "Multiple-Scattering Microfacet BSDFs with the Smith Model".

Essentially, the improvement is that unlike classical GGX, which only models single scattering and assumes
the contribution of multiple bounces to be zero, this new model performs a random walk on the microsurface until
the ray leaves it again, which ensures perfect energy conservation.

In practise, this means that the "darkening problem" - GGX materials becoming darker with increasing
roughness - is solved in a physically correct and efficient way.

The downside of this model is that it has no (known) analytic expression for evalation. However, it can be
evaluated stochastically, and although the correct PDF isn't known either, the properties of MIS and the
balance heuristic guarantee an unbiased result at the cost of slightly higher noise.

Reviewers: dingto, #cycles, brecht

Reviewed By: dingto, #cycles, brecht

Subscribers: bliblubli, ace_dragon, gregzaal, brecht, harvester, dingto, marcog, swerner, jtheninja, Blendify, nutel

Differential Revision: https://developer.blender.org/D2002

GPencil: Eraser respects "Selection Mask" when in EditMode

Fix minor typo - Was m[3][4] instead of m[4][4] for a 4x4 matrix