Blender Git Loki

Merge branch 'master' into blender2.8

Object Mode: move logic to 'object_modes.c'

Was mixed with edit-mode, centralize mode switching in a single file.

No functional changes.

Cleanup: remove object-mode 'reset' check

Silently fail when attempting to enter a mode that's not compatible
with the object.

Cleanup: rename 'screen_changed_update'

Match 'workspace_change_update'.

WorksSpace: sync object-modes when changing scene

Note that this code will likely be generalized,
currently each new case is a little different though
so it's too early to move them into general functions.

FCurve: only calculate single axis length

Was calculating all 3

Fix building w/o Python

Also minor cleanup.

Cleanup: remove print

Remove legacy code used for sequencer preview image

This (now removed code) calls gl_Vertex deprecated draws. It was doing
background drawing (color gradient, flat background) which is not used
by any engine.

Discard non-free axis scaling in Maintain Volume to improve 2.79 compat.

It seems the reason the old version of the constraint overcompensates
as reported in T48079 is to allow the constraint to work with uniform
scaling on all axes. However the way it did that actually _requires_
uniform scaling for the constraint to work correctly, and breaks if
only the free scaling axis is used to avoid redundant channels.

This version attempts to allow both by discarding scaling in the non-
free directions instead of applying the correction on top of it.

Python tests: Split re-usable test related functionality to a module

The idea is to avoid re-implementing this for an upcoming FFmpeg tests.

Refactor: Merge non-functional-change part of 'edit normals' 2017 GSoC.

This merges changes in internals, runtime-only of existing custom
normals code, which make sense as of themselves, and will make diff of
soc branch easier/lighter to review.

In the details, it mostly changes two things:

* Now, smooth fans (aka MLoopNorSpaceArray) can store either loop
indices, or pointers to BMLoop themselves. This makes sense since in
BMesh, it's relatively easy to get index from a BMElement, but nearly
impracticable to go the other way around.

* First change enforces another, now we cannot rely anymore on `loops`
being NULL in MLoopNorSpace to detect single-loop fans, so we instead
store that info in a new flag.

Again, these are expected to be totally non-functional changes.

More clean of macros with an _END and no _BEGIN

Follow up on 7aed2de798b1e5f8663e.

Fix assert on exit edit-mode

3D View: minor selection tweaks

- don't initialize the GL context when cache is used.
- don't run second pass when the first one has no hits.

Merge branch 'master' into blender2.8

Cycles volume: fast empty space optimization by generating a tight mesh
around the volume.

We generate a tight mesh around the active voxels of the volume in order
to effectively skip empty space, and start volume ray marching as close
to interesting volume data as possible. See code comments for details on
how the mesh generation algorithm works.

This gives up to 2x speedups in some scenes.

Reviewed by: brecht, dingto

Reviewers: #cycles

Subscribers: lvxejay, jtheninja, brecht

Differential Revision: https://developer.blender.org/D3038

WorkSpace: fix mode exiting w/ multi-window

Activating an object exited modes for all other objects in the layer.
Now check these objects aren't active in other windows first.

Cleanup: macro's w/ an _END need a matching _BEGIN

Convention from 2.7x, since some looping macros don't need an '_END',
it avoids confusion to keep this.

Missing assignment in object mode sync

Own error in recent change (1aeb9294f4a)