Blender Git Loki

Constraints: refactor the D7437 patch adding Custom Space for constraints.

As mentioned in the comments to that patch, I had an idea for
a different way to do some technical aspects, but it was too
complicated to force changes in the original patch. Thus I submit
this follow up patch.

First, instead of modifying all the get_constraint_targets and
flush_constraint_targets callbacks, introduce wrapper functions
for accessing constraint targets, convert all code to use them,
and handle the new reference there uniformly for all constraints.

This incidentally revealed a place in the Collada exporter that
didn't clean up after retrieving the targets.

Also, tag the special target with a flag so other code can
handle it appropriately where necessary. This for instance
allows dependency graph to know that the Use B-Bone Shape
option doesn't affect this specific target.

Finally, rename and simplify the function for initializing the
custom space, and make sure it is called everywhere necessary.

Differential Revision: https://developer.blender.org/D9732

EEVEE: Lookdev: Add back lighting support

This does not include reference spheres rendering.

The approach is a bit different than before.
Now we use a `bNodeTree` to control the rendering of lookdev. This
generates a `GPUMaterial` that is stored per `Instance`. This way
rendering lookdev is just updating the temp light cache using this
material as world material. Removing the use of custom shader.

This introduces a small hack in order to bind the studiolight hdri after
the nodetree glsl parsing.

The background display however is still using a custom shader in order
to sample the world cubemap with different roughness.

The view space option of the studiolight is now faster by using a
transform before shading instead of rebaking the lightprobe constantly.
This should not have any particular impact on render time.

Knife: Implemented D10853 - Constrained angle mode improvements

This is the first commit for the GSOC 2021 Knife Tool Improvements project. It implements D10853 which adds more control over constrained angle mode through new UI elements and number key input.

Merge branch 'master' into eevee-gpencil

Curve deform working slightly better

EEVEE: Light: Fix culling in orthographic view

EEVEE: LightCache: Fix broken visibility sampling

EEVEE: LightCache: Fix broken light bounce

Merge branch 'master' into eevee-gpencil

EEVEE: Fix world probe rendering objects

Was leftover of a test.

Merge branch 'master' into override-recursive-resync

Sculpt: Make subdivision surface modifier use the On Cage option

Fix compile error on windows.

Merge branch 'master' into override-recursive-resync

Conflicts:
source/blender/blenkernel/intern/lib_override.c

Fix crash when extracting multiple iterators.

Merge branch 'master' into temp-geometry-nodes-curve-deform-node

Cycles X: add path state compaction for GPU rendering

Before enqueing more work tiles, compact the path states so that all active
states are at the start. This improve coherence by avoiding paths from
different tiles to be interleaved.

It only provides minor performance benefits at this point, and only on
some GPUs. But it can be a useful building block for further optimizations.

Differential Revision: https://developer.blender.org/D11346

Cleanup: rename extract_run_and_finish_init > extract_run_single_threaded.

Cleanup: remove `extract_extract_iter_task_data_create_mesh`.

Cycles X: tweak inlining flags in preparation of shader raytracing

No difference by itself, but will be needed to keep inlining behavior the same
after the addition of the new kernel.