Blender Git Loki

PSculpt: Code cleanup - Remove dead code and tweak formatting

PSculpt: Reduce the strength of the curl and twist brushes

From previous feedback, the curl and twist brushes were far too strong,
making them hard to use whe ntrying to do careful posing work. This commit
removes the x10 boosting factor that was being used to make these get applied
at a "reasonable" speed; while this was a good idea for demos, it was quite
bad for actual posing work.

PSculpt: Tweak keybindings

* Q-LMB and L-Shift-LMB are used for painting now. The "shift" variant is used for
inverting the effect of the brush

* Alt-Q = Brush size
* Alt-Shift-Q = Brush strength

* Q-RMB - This is not used now, but has been reserved for showing a popup menu
to allow users to quickly change brushes without having to go through the panels
(just like with Grease Pencil)

CMake support for PSketch and PSculpt

PSculpt: Initial port of the old Pose Sculpting codebase from 2012 to modern Blender

Pose Sculpting allows animators to pose rigs using a brush-based "sculpting"
paradigm. It has multiple similarities to the sculpting tools for meshes,
the particle editing tools, and the upcoming Grease Pencil stroke sculpting
features. In each of these cases, we are trying to make it easier and faster
to work, by allowing artists to seamlessly affect a whole bunch of points/items
at the same time by varying amounts.

Current Status:
* Use Q-LMB and Q-RMB to sculpt strokes. Unlike in the past, Pose Sculpting is
not a separate mode, but instead works more like Grease Pencil drawing, which is
non-modal.

* Settings for brushes can be found in the "Sculpt" tab of the toolbar

* All the brushes work as they did before. That includes the dodgy behaviour that
the "Draw" brush had (fixing this is a top priority!), and/or any other random
bugs that the others may have had. Also, all the brush strengths/etc. are left
as-is so far (to be tweaked... they are still too strong)

PSKetch: Some uncommitted WIP fixes/tweaks

PSketch: Tweaks so that it doesn't immediately wreck non-connected chains

Pose Sketching: First working prototype of "Direct Mode"

This commit introduces a new tool which allows users to draw the shape that
a chain of bones should form, and have the bones be transformed to fit.

Usage:
1) Select a chain of bones. You must select at least 2 bones, and they should
ideally be connected (or appear to be) for best results.
2) EKEY to invoke the operator
3) Draw a stroke (*)
4) Your rig should now be posed

(*) This operator uses Grease Pencil strokes to provide its sketch input.
Please ensure that strokes are drawn in 3D space (not view), and that
"Continous Drawing" is not enabled.

The currently implementation is still heavily WIP, and suffers from a number
of limitations. It is also just "simpler" of the two initial algorithms planned.
* It currently only sets the pose_mat values (and the pose_head/tail) values.
To keyframe any poses made this way, use "Visual Keying" or else the poses
won't hold.

* There is currently a bug where each subsequent attempt to pose the rig
will result in incorrect bone alignments. More work is required to figure
out why this occurs.

PSketch: Fix bug where subsequent invocations would get placed wrong

This was because the calculations for the new tail positions was wrong.
It was only doing a fixed offset, which meant that the tails were not
where the bones were shown to be.