Blender Git Loki

Minor fix for lost variable declaration during cherry-picking.

Fix for warnings/errors

Conflicts:
source/blender/blenkernel/intern/key.c
source/blender/blenkernel/intern/particle_system.c
source/blender/makesrna/intern/rna_particle.c

Reorganizing hair dynamics UI layout a bit to make settings slightly
more intuitive.

Also removed a couple of unused or useless features from the UI:
* collider friction is unused and replaced in favor of true collision
* spring damping refers to structural springs (stretch), which is
not noticable in hair due to extreme stiffness atm.
* pressure factors are not sure since this feature is too unstable atm.

Conflicts:
release/scripts/startup/bl_ui/properties_particle.py

Moved render simplification function for particle distribution into the
distribution code.

Removed unused variable.

A little bit of code sanity by splitting particle distribution function
by type.

Instead of squashing totally unrelated code into the same monster
function.

Moved particle code for distributions into own file to make hacking
easier.

This code is badly broken and needs to be replaced, but at least having
a workable code structure might help with quick hacks to fix the worst
cases.

Removed unused line.

New hair editing feature "Shape Cut", for cutting hair based on a mesh
shape instead of a brush tool.

The brush cutting tool for hair, while useful, is not very accurate and
often requires rotating the model constantly to get the right trimming
on every side. This makes adjustments to a hair shape a very tedious
process.

On the other hand, making proxy meshes for hair shapes is a common
workflow. The new operator allows using such rough meshes as boundaries
for hair. All hairs that are outside the shape mesh are removed, while
those cutting it at some length are shortened accordingly.

The operator can be accessed in the particle edit mode toolbar via the
"Shape Cut" button. The "Shape Object" must be set first and stays
selected as a tool setting for repeatedly applying the shape.

Switched back to blender implicit solver for merge.

Unified the main Eigen solver function a bit for constrained/unconstrained
solver variants.

Ported the remaining implicit solver functions for Eigen.

Also added a couple of utility wrapper functions for Eigen types to make
interfacing with plain float arrays and blenlib math easier.

Updating Eigen implicit dynamics solver implementation to adhere to the
new mass-spring solver API.

Conflicts:
source/blender/physics/intern/implicit_eigen.cpp

Fix for inverted condition: hair data needs to be rebuilt when the
cloth DM does not exist.

Cleanup: Removed the unnecessary cloth solver abstraction (there is only
one solver anyway), and split some particle cloth functions for clarity.

Conflicts:
source/blender/blenkernel/BKE_particle.h
source/blender/blenkernel/intern/particle_system.c
source/blender/blenloader/intern/versioning_270.c
source/blender/makesdna/DNA_particle_types.h
source/blender/makesrna/intern/rna_particle.c

enum instead of #define for cloth vertex flags.

Removed accidentally committed debug print.

Use the generic task scheduler for threaded particle tasks, i.e.
distribution and path caching for child particles.

This gives a significant improvement of viewport playback performance
with higher child particle counts. Particles previously used their own
threads and had a rather high limit for threading. Also threading
apparently was disabled because only 1 thread was being used ...

Removed block matrix indices storage from ClothSpring struct.

This is not necessary: the implicit solver data can keep track instead
of how many off-diagonal matrix blocks are in use (provided the
allocation limit is calculated correctly). Every time a spring is
created it then simply increments this counter and uses the block index
locally - no need to store this persistently.

Removed unused force arguments for angular bending springs and avoid
redundant calculation for counterforces.