Blender Git Loki

Vertex Paint: use view normal w/ 2D falloff

When projecting to the view, cull faces pointing
away from the view normal.

Vertex Paint: use brush front-face setting

Follow sculpt mode more closely by using the brush front-face option.

Sculpt: use tube falloff when calculating normals

Also apply 2D clamping for other tools when the option is set.

Sculpt: clamp normal to plane w/ projected falloff

Allows for editing outlines w/o pushing geometry towards/away from
the view.

Fix ruler access from search pop-up

D2831 by @1xundoredo

Cleanup: style

Gawain: Simplify / optimize the shader interface.

This changes quite a few things:
- Drops the allocation of inputs as a chunk.
- Merge the linked list system into the Gwn_ShaderInput.
- Put name buffer into another memory block, easily resizable.
- Use offset instead of char* to direct to input name.
- Add only requested uniforms dynamicaly to the Shader Interface.

This drops some minor optimisation and use a bit more memory for small shaders (which are fixed count).
But this saves a lot of memory when using UBOs because the names and the Gwn_ShaderInput were alloc'ed for every UBO variable.
This also reduce the Shader Interface initial generation.
The lookup time is left unchanged.

Revert "Gawain: Optimize out extra level on top of ShaderInput"

This reverts commit 5514d2df1c6d9f2f108336e46b0db14316610d24.

Fix T52514: don't clear filename when dropping directory path in file browser.

Fix T52998: disabled menu entries responding to key shortcuts.

Fix T53002: Batch-Generate Previews generate empty or none image for large objects.

Camera clipping was left to default values, which won't work well for
very large (or small) objects. Now recompute valid clipping start/end
based on boundingbox of rendered data, and final location of camera.

Fix T53001: more workarounds for crash in AMD compiler with recent drivers.

Code refactor: split displace/background into separate kernels, remove luma.

Sculpt Mode: 2D falloff option

This makes brush influence into a tube instead of a sphere.
It can be used along the outline of a mesh to adjust it's silhouette.

Note that all this takes advantage of changes from vertex paint,
from testing this seems useful so exposing from the brush options.

Gawain: Optimize out extra level on top of ShaderInput

This is an internal structure, and we don't put it to a list for anything else
that hash collision resolution. No need to have dedicated entry here, saves us
from extra allocation and pointer dereference.

Draw manager: Avoid unneeded memory malloc/free when attempting to create missing uniform

Gawain: Make builtin uniform lookup to be O(1)

Gawain: Lookup uniforms and attributes from buckets

This way we reduce number of loops from look-over-all-inputs to
loop-over-collision, which is expected to be much less CPU ticks.

There is still possible optimization: use memory pool of some sort
to manage memory needed for hash entries, but that will only speedup
shader interface construction / deconstruction time.

There are also some trickery happening to speed up process even more
in the case there is no hash collisions detected when constructing
shader interface.

Gawain: Force hashing function to be inlined

Makes sure we don't waste CPU ticks on function call in such a time critical
area.

Vertex Paint: apply when cursor isn't over faces

This behavior makes more sense for sculpt, less so for painting.
Restores non PBVH behavior, adding `BKE_pbvh_find_nearest_to_ray` -
similar to ray-cast except it finds the closest point on the surface.