Blender Git Loki

Fix missing 3D viewport solid shading mode request for UVs and vertex colors

This probably fixes no current issues, because there is another one causing
these to be computed unnecessarily.

Cycles: Followup fix for my previous commit, there were uninitialized variable.

Cycles: Another fix for deferred ray marching, this time a buffer underflow.

Cycles: More consolidation for deferred ray marching

Cycles: Deferred ray marching now correctly spearates multiple intersections with the same object

Fix T70060: Add bgl wrapper for glVertexAttribIPointer

Cycles: Fixed bug where deferred ray marching would always march to infinity

Cycles: Fixed a mistake in my previous volume change - deferred ray marching would count multiple intersections of the same volume incorrectly.

Cycles: adding provisions to prevent volume stack overflow, don't add the same volume object twice even when there's empty space in between

userdef_defaults for 'Render In' and 'File Browser'

Otherwise --factory-startup would e.g render as `Keep User Interface`
(which is supposed to be `New Window` by default)

Reviewers: brecht

Differential Revision: https://developer.blender.org/D5851

Clean-up/safety check in new BKE_mesh_copy_settings().

From rBe7a514369fe70, since I did not have time to do proper review
in D5808...

Note that we could also consider that shallow copy of src should never
be dst of that function and add some asserts instead. For now going the
safest and simplest way though.

Cycles: fixed BV-5 - state update on volume bounce was overwriting bounce index and caused early path termination

Cycles: Fixed an issue with deferred ray marching where it wouldn't update the volume stack properly for volume scattering.

Cleanup: Spelling in comment

Fix T67934: Weight paint doesn't work with Subsurf/Multires

This is a regression since PBVH was introduced for weight paint.

The solution is: treat subsurf and multires modifiers as deforming
ones for the weight painting. This is an easiest solution to make
PBVH use subdivided location of original vertices.

This change could simplify some of the weight paint by removing
the grids check, since PBVH is not supposed to be built from grids
in this case anymore.

Differential Revision: https://developer.blender.org/D5751

Subdiv: Add vertex deformation callback to multires/subsurf

Currently unused but the intention is to use this to hook up these
modifiers to a generic deformed PBVH to make it easier to sculpt or
paint on a subdivided mesh.

Subdiv: Add deformation-only subdivision

Is intended to be used to generate an array of coordinates of coarse vertices
placed to the final subdivided position.

Subdiv: Cleanup, comments

Cycles: Small fix for deferred ray marching.

Fix T66154: viewlayer hide/exclude settings getting lost for linked collections

The problem was that the object and collection pointers in Base and
LayerCollection would get lost of file read. Normally such ID pointers would
be resolved by pointing to an ID_ID placeholder which has the datablock name,
and then replacing it will the real datablock. However ID_ID is only written
for directly linked datablocks.

This adds the concept of an indirectly linked datablock with a weak reference
to it. For this we write an ID_ID_WEAK_REF code, which is a reference that
will only be resolved if the datablock was read for another reason.

Differential Revision: https://developer.blender.org/D4416