Blender Git Loki

Removed the ID_PA code used for ParticleSettings.

Removed some unused declarations for boids code.

Cleanup: Move texture definitions to util, to avoid bad level include.

Curve draw fix w/ surface offset + only-first enabled

In this case the initial offset needs to be applied to the rest of the stroke.

Merge branch 'master' into temp_remove_particles

Fix T48157: 3D view's depth of field isn't displayed correctly with scene units scale.

focus distance is given in BU, no need to scale it at all.

Fix T48139: Checker texture strange behavior in cycles

Seems particular CUDA implementations has some precision issues,
which made integer coordinate (which was expected to always be
positive) to go negative.

UI: copy to selected: add 'single'/'all' options to buttons' menu when relevant.

Same as reset or anim keyframe/driver operators... Inconsistency reported by Leon Cheung
through IRC, thanks.

Code Cleanup: Fix up various odds and ends

Code Cleanup: Remove unused define left over from earlier versions of this code

Remove a leftover from older code

Cycles: Optimization to spatial BVH build

Simple fix: release lock earlier.

Reduces spatial split build time from 96 to 53sec on the Bunny.blend
(using studio Intel for benchmark).

NOTE: Timing difference is not that spectacular when comparing numbers
with builds before memory optimization, but even then it's about 20%
faster build.

Fix T48151: Brush texture overlay won't refresh automatically in UV editor when changed in buttons window.

Simple solution is to get rid of this stupid `rna_TextureSlot_brush_update` func, and do what it was doing directly
in BR case of `rna_TextureSlot_update`. That way, all updates to brush texture will invalidate correctly the overlay.

Note that this double definition of texture pointer for brushes looks rather fishy, am really not convinced this helps
keeping things simple and clear at all (what happened here is that texture selector in image paint editor was using
'texture' member of brush itself, which was performing correct RNA update, while context-based brush texture selector
from buttons space was using 'texture' member of the TextureSlot struct, which had default texture update callback
which was not invalidating overlay).

New freehand curve drawing tool

- Access with Shift-LMB or from the 'Create' toolbar tab.
- Uses curve fitting for bezier curves, with error and corner angle options.
- Optional tablet pressure to curve radius mapping.
- Depth can use the cursor or optionally draw onto the surface,
for the entire stroke or using the stroke start.
- Stroke plane can optionally be perpendicular to, or aligned to the surface normal.
- Optional radius tapering and for start/end points.
- Supports operator redo and calling from Python.

Add lib for n-dimensional cubic curve fitting

This will be used for calculating bezier curves from freehand drawing,
may be used for other areas too.

Original code from GraphicsGems, 1990 (FitCurve.c),
with updates from OpenToonz, under 3 clause BSD license.
with own minor modifications for integration with Blender:
- support adding extra custom-data.
- improved handle clamping.

Cycles: Support heat volume attribute

Similar to velocity, it was kind of supported by the mesh manager but
was missing a code in BlenderSession to get actual values.

In Cycles Heat is an attribute which goes from -1 to 1, where -1 is
the coldest ever temperature, 1 is the hottest ever one.

Cycles: Improve error print a bit

Tests: Fix wrong hash after "no redundant zeroes" commit

Drivers Editing: Added "Copy/Paste" buttons beside "Add Variable" for copying all variables from one driver to another

This was a feature request from a few years back (IIRC from ZanQdo?) to make it
easier to reuse one set of driver variables across several different drivers.

Dev Notes:
* Finally it's done! All that trouble for two little buttons.
* Grr... cmake... grrr!

NLA Copy/Paste Modifiers: Apply similar fixes as those done in Graph Editor