Blender Git Loki

Sculpt: experimental bending constraints for cloth
brush.

See "bending" checkmark in the cloth settings.

Changes based on Review by Hans Goudey (HooglyBoogly)

Sculpt: don't set strength to inherit from
scene defaults by default.

Sculpt: improve accuracy of tri in brush
test for dyntopo

EEVEE: Subsurface Scattering: New implementation

This new implementation follows the technique described in
"Efficient screen space subsurface scattering Siggraph 2018".

Compared to the old implementation it fixes a lot of issues at
the cost of it being slower. This fixes:
- Light leaking between different objects.
- Light leaking between different surfaces with different depths.
- SSS radii are now "texturable" per pixel. No SSS surfaces limits.
- Noise should be lower.
- Precomputation is only done once for all SSS surfaces which lowers the
per material storage and precomputation time.

Implementation is also simpler as it is only a one pass processing.

We differ from the reference presentation by not precomputing the
RGB weights per samples. We actually compute them on the fly in order
to support varying SSS radii.

Notes:
- SSS IOR and SSS anisotropy are not supported.
- Object level light leak prevention might not work for high number of
objects in the scene (> 1024). In this case light leak might occur.
Adding or deleting (hidding) objects in the scene might change which
objects can leak.

EEVEE: Material: Add thickness output

This only adds the output but the output is not yet used.

This thickness output is meant to control the aspect of subsurface,
refraction, absorption and volume shaders.

The value expected is the mean thickness inside the object at the
shading point. The source can be a vertex color or a texture map baked
from a raytracer.

EEVEE: Transmittance: Add back light transmittance

Same as SSS this has been rewritten to support varying SSS radius.

Instead of relying on shadowmap hack to improve the transmittance
artifact (previously called translucency) we exposed a min thickness
output that will reduce the maximum of light bleeding that can happen
at the shading point. This is far from perfect but at least it is
tweakable.

The effect is now cheaper and the option to enable it is now gone.
It can always be artificially disabled by making the thickness bigger
than the sss radius.

The effect is always enabled for all SSS surfaces and will even be
applied on forward shaded object (alpha blend mode).

EEVEE: Fix Crash with some geometry type

EEVEE: Fix smooth transition when using render borders

The first sample buffer is fullscreen and needs to have its uvs
corrected to match the render border viewport.

Implement `AssetCatalogCollection::deep_copy()`

Implement a deep copy function on `AssetCatalogCollection` that can be
used to create snapshots for storage in an undo stack.

Merge branch 'master' into asset-greasepencil

Cleanup: Asset Catalogs, make separate structure for a catalog collection

The collection of catalogs, as managed by a single instance of
`blender::bke::AssetCatalogService`, is now stored in a separate class
`AssetCatalogCollection`.

This opens the door to storing & restoring deep copies of that class,
for an upcoming undo system.

Asset Catalogs: Fix unit test on Windows

Force native slashes before comparing paths; on Windows mixing separators
caused a unit test to fail.

No functional changes.

Merge branch 'temp-lineart-contained' into lineart-shadow

Sculpt: fix sharp brush, new experimental
mode was being enabled when it
shouldn't be

Merge remote-tracking branch 'origin/master' into temp-lineart-contained

Sculpt: fix broken jitter and smooth
stabilize brush settings.

Cleanup: Use `_` suffix for non-public members in Compositor

To follow the style guide.

Cleanup: Convert camelCase naming to snake_case in Compositor

To follow the style guide.

Cleanup: Remove unused includes in Compositor

And move unneeded includes in frequently used headers
to source files.

Slightly reduces compilation time.