Blender Git Loki

Copied high-level operator code from the paint/sculpt system as a basis
for brush-stroke operators in hair edit mode.

Hopefully this can help avoid some redundant code and ensure consistent
keymapping etc.

Revert previous hair edit operator scaffolding and port over the old
operator for strokes instead.

The paint system is much too complicated and does not add any real
advantage at this point.

Calculate some basic info about mouse strokes and context and pass it
on to a general hair tool function.

New image file icons for hair brush tools and an according tool enum in
the Brush RNA.

Intermediate commit: switching strand edit data to BMesh.

Hair/Strand editing will only use a subset of the bmesh topology and
expect a specific topology that needs to be verified and enforced.
However, this extra requirement is much less work than reimplementing a
whole edit data system with the same feature set as bmesh and avoids
much redundant code.

Fix for particle-to-bmesh: only was looping over totvert instead of
pa->totkey.

Fix for verts-of-strand iterator: After last edge step has to set the
edge to NULL to avoid infinite looping over the same edge (1-elem disk).

Basic particle data reconstruction when exiting edit mode.

First customdata layer for particle mass.

This is more for testing purposes, since currently there is only a
single mass property for the psys as a whole. This should change in the
future though, to allow variable mass per strand or vertex.

Store the hair key weight in edit mode.

Currently particles only have a single weight value, controlling
pinning in the simulation (for root and virtual root verts) and goal
force scaling. This will be replaced by a full vertex group weight
system eventually.

CustomData layer for storing hair root locations as MSurfaceSamples.

This requires converting the old messy particle num/num_dmcache/fuv/foffset
data into the new mesh samples, which can potentially introduce floating
point errors and inaccuracies due to lack of face index mapping in the
new system. However, in any well-constructed particle system the hair
roots should be nearest to their num face, so mapping would be accurate
enough. If necessary face index data could be added to samples as a
legacy code hack, but probably it's best to eventually replace the
hair system as a whole anyway.

Fix for verts-of-strand iterator: This requires a second pointer in
addition to the edge, otherwise the last point is omitted.

Free strand edit memory after use.

Removed deprecated code.

New drawing code for hair edit mode.

Fix for GL buffer size for edges, needs to 2x for two vertex indices.

New customdata type for mesh surface samples.

Switched the hair edit data to a bmesh-like structure for consistency.

This means using mempools to store curve and vertex data, which allows
arbitrary addition and removal of data more easily. Also this includes
an iterator system similar to bmesh iterators (although the simpler
topology makes it a lot less complex).

More work on particle conversion methods for hair edit mode.

Finished the particle-to-edit conversion function.