Blender Git Loki

Cycles: add object level holdout property, to replace Z mask layer.

Fix unneeded legacy OpenGL call in Cycles viewport drawing.

Minor cleanup for own recent commits.

Merge branch 'master' into blender2.8

Getting rid of OMP: first usage of new parallel BMesh items iteration instead.

`BM_mesh_normals_update` was converted from OMP to new parallel iterator code,
basic test with heavily subdivided cube (24.5k faces) gives:
- old OMP code: average 10ms per run.
- new BLI_task code: average 6ms per run.

So new code seems to be easily 40% quicker, in addition to getting rid of OMP. ;)

Reviewers: sergey, campbellbarton

Differential Revision: https://developer.blender.org/D2930

BMesh: add limited support for parallelization over some basic iterators.

This merely uses new memloop/task looper over vertex/edge/face mempools.

Quite obviously, only BM_VERTS/EDGES/FACES_OF_MESH iterators are
supported.

atomic_ops: add `atomic_cas_float` helper.

Add a new parallel looper for MemPool items to BLI_task.

It merely uses the new thread-safe iterators system of mempool, quite
straight forward.

Note that to avoid possible confusion with two void pointers as
parameters of the callback, a dummy opaque struct pointer is used
instead for the second parameter (pointer generated by iteration over
mempool), callback functions must explicitely convert it to expected
real type.

Also added a basic gtest for this new feature.

Add ability to use more than one mempool iterator simultaneously.

This will allow threaded tasks to 'consume' all mempool items in
parallel tasks, each one working on a whole chunk at once (to reduce
concurrency managing overhead).

Merge branch 'master' into blender2.8

atomic_ops: Copy/adapt static assert macro from BLI_utildefines, and use it.

Checking for type sizes is much nicer with a static assert!

Add non-gcc variant of static assert macro.

Adapted from http://www.pixelbeat.org/programming/gcc/static_assert.html.

Note that this macro just discards error message, so error when building
is much less nice than with gcc's _Static_assert... But error log will
point to right place in code, so should still be OK.

Fix T53145: bevel tool fails when used a second time.

Pixel size was not initial early enough. For first time this was not a problem
because the bevel amount starts at 0 then, and after the mouse moves the pixel
size is initialized. For the second time the bevel amount starts at a non-zero
value, and it failed then.

Merge branch 'master' into blender2.8

Fix T53171: lamp specials strength tweak fails with renamed emission nodes.

Fix T53360: crash with GLSL bump mapping and missing group output node.

Cleanup: Rename ViewLayer *sl > ViewLayer *view_layer

Fix T53276: encoding output quality UI clarification.

Fix T53357: harmless assert after recent addition of render time pass.

Fix inaccuracy when storing material ID pass in half float multilayer EXR.

These and other non-RGB passes should always be stored as full float, the
precision loss is too unpredictable.

Related to T53381, but that one is about file output nodes where we don't
know the type of data being saved currently.