Blender Git Loki

Dyntopo: code cleanup

Cycles X: remove unused megakernel for GPU rendering

This reduces OptiX runtime compilation time to less than a second here.

Differential Revision: https://developer.blender.org/D11313

Apply D9974: Sanitize threaded preview creation with undo

With undo/redo after creating assets, previews of the "Current File"
asset library would often go missing, e.g. see T83884.

The preview generation in a background job will eventually modify ID
data, but the undo push was done prior to that. So obviously, an undo
then would mean the preview is lost.

This patch makes it so undo/redo will regenerate the preview, if the
preview rendering was invoked but not finished in the undone/redone
state.

The preview flag `PRV_UNFINISHED` wasn't entirely what we needed. So I
had to change it to a slightly different flag.

Cycles X: Remove usage of mega-kernel

The usage of the mega-kernel is commented out with this change.

There are few benefits of removing the mega-kernel:

- It takes extra time to compile and space to ship.
- It is not compatible with features like shadow catcher.

The rest of the changes are related on attempt to avoid performance
loss in various scenes. Those changes include:

- Make work tile smaller in size. This makes the work tile more
friendly for greedy scheduling when adaptive sampling is used.
Currently this is achieved by keeping pixel same the same and
lowering number of samples per work tile. The idea behind this
is to avoid dramatic change in order in which pixels are
scheduled for sampling.

- Keep tile size dimensions a power of two.
This lowers the unused path states (which can be watched with

./bin//blender --debug-cycles --verbose 3 2>&1 | grep "Number of unused path states"

In own tests it seems that we barely "waste" path states now.

- Make it so tiles are scheduled in the order of samples first.
As in: keep pixel-space coherency, similar to how it is done
in the `get_work_pixel()`.

- Only keep extreme case tests for the tile size calculation.
Avoids some unnecessary updates, while still ensuring correct
behavior in extremes.

The timing goes as following:
```
RTX 6000 (Turing)

new cycles-x
bmw27.blend 10.8964 10.4269
classroom.blend 17.4476 16.6609
pabellon.blend 9.77167 9.14966
monster.blend 10.3662 12.0106
barbershop_interior.blend 11.9445 12.5769
junkshop.blend 16.3556 16.5213
pvt_flat.blend 16.5317 17.4047

RTX A6000 (Ampere)
new cycles-x
bmw27.blend 7.74059 7.65293
classroom.blend 10.775 10.9143
pabellon.blend 6.00643 5.85334
monster.blend 6.79277 8.0134
barbershop_interior.blend 8.39941 8.47159
junkshop.blend 10.4258 10.9882
pvt_flat.blend 10.2752 10.8821
```

Not entirely happy with the results: there are some very nice speedups
interleaved with some slowdown. Although, slowdown is within 5%, so
hopes that we can gain it back with more tricks from the sleeves.

Some thing to try:
- Try lowering tile size in pixels
- Try better alignment of tile size with number of threads on a
multiprocessor.

This change is a combined brain activity from Brecht and myself.

Differential Revision: https://developer.blender.org/D11311

Merge branch 'asset-browser-poselib' into asset-browser

Remove unnecessary `NonCopyable` mixin usages

Merge branch 'master' into asset-browser-poselib

Merge branch 'master' into asset-system-filelist

Fix compile errors after merge conflicts

Merge branch 'master' into asset-browser

Merge branch 'master' into override-recursive-resync

Cycles X: More flexible tile scheduling support

Allow tiles with sample range smaller than the currently rendering
number of samples.

The previous code was trying to support it already, but it had some
mistakes in the math.

Currently should be no functional changes.

Cycles X: Increase verbosity level for kernel timings

Allows to more easily access overall kernel time execution without too
much flood in the terminal which could affect overall timing.

Version bump 2.83.15 stable.

2.83.14 missed cuda/optix kernels in distribution. Better to bump the
version.

Cycles X: Run init_from_camera kernel for all tiles

Avoids pointer magic which is not necessarily supported by all compute
backends and allows to ensure there are no extra latency caused by
multiple kernel launches.

Currently this does not bring performance improvements, but this change
opens doors for more compute backends and makes it possible to test
different tile slicing and scheduling strategies.

```
init_all_tiles cycles-x
bmw27.blend 10.3444 10.326
classroom.blend 16.476 16.6067
pabellon.blend 9.13914 9.13556
monster.blend 11.9673 11.963
barbershop_interior.blend 12.4566 12.4414
junkshop.blend 16.4764 16.491
pvt_flat.blend 17.288 17.2757
```

Differential Revision: https://developer.blender.org/D11304

Cycles X: Move Pass to its own file

While doing so found that the pass type enum could have double amount
of entries: items are added when initializing pass node and when
setting up film's display pass enum.

Cleanup: Use const qualifier in Cycles X scene parameters comparator

Cleanup: Remove unused pass stride accessor in Cycles X

Unused function, which usage was actually limited: the stride was only
correct after device update.

Cleanup: Remove unused table offset access in Cycles X

Cleanup: Follow naming convention for private members in Cycles X