Blender Git Loki

Pampering the stupid MSVC compiler again, it fails to build valid C code.

Merge branch 'master' into gooseberry

Added new header for Eigen utility classes.

These make passing data between Eigen vector and matrix types and plain
C arrays more convenient.

Updated a few comments.

Compile hair volumetrics code as C++, so we can use Eigen easier.

Minor debug code fix.

Use a fixed, uniform cell size for hair continuum grids.

This is a bit more awkward for artists to use, but necessary for
a stable solution of the hair continuum calculation. The grid size is
defined by the user, the extent of the grid is then calculated based on
the hair geometry. A hard upper limit prevents bad memory allocation
in case too small values are entered.

Removed unused voxel_filter_size DNA property.

This is an artifact of earlier attempts to implement velocity smoothing,
but doesn't work anyway.

Renamed HairVertexGrid to HairGrid, since it's not actually storing
hair vertex data.

Removed unused "collider grid" struct from hair volumetrics.

This is a leftover from previous approach of hair collisions (with
insufficient results). The hair volumetrics actually implements
"collision" with solid objects as well, but uses a Neumann boundary
condition on the main grid for this purpose.

Better grid rasterization method for hair volumetric grids.

This is based on the paper
"Detail Preserving Continuum Simulation of Straight Hair"
(McAdams, Selle, Ward, 2009)

The main difference is that hair line segments are used rather than only
rasterizing velocity at the vertices. This gives a much better coverage
of the hair volume grid, otherwise gaps can be produced at smaller grid
cell sizes and the distribution is uneven along the hair curve.

The algorithm for rasterizing is a variation of Bresenham's algorithm
extended onto 3D grids.

Add mapping to properties for widgets.

Still pretty much exploring the best way to move here but currently this
works by wrapping objects in RNA pointers, pretty much like buttons do.

Also modified the arrow widget for lamps to use the new code. The new
"unmbrella" widget works now as expected for lamps - of course fine
tuning is also needed.

New debug element "circle" for simulations, which is quite useful for
visualizing scalar fields.

Resurrection of 2.49 feature:

Ghosting of original arrow position while we are interacting with an
arrow widget.

Make projection code for arrow widget better. Also add some code to
allow tweaking of properties

Debug grid drawing for hair volume was drawing one subdivision too many.

Merge branch 'master' into wiggly-widgets

Warnings

Merge branch 'master' into gooseberry

Support animation of camera dof properties.

Also minor cleanup