Blender Git Loki

Visualization: compute normals for voxel box drawing.

Visualization: draw full boxes for voxels.

Also avoid creating several instances of the same vertex.

Exporter: option to write grids as 16-bit half floats.

This is just for storing on disk, the grids are converted back to full
float format upon reading. Also this affects all grids to be written for
now.

Merge branch 'master' into openvdb

Add a function to allocate and set default values for the drawing
properties.

One more de-duplication.

Rework the UI for displaying the OpenVDB data.

Cleanup: de-duplicate drawing code.

Add a level of detail scheme to reduce the number of voxels to be drawn.

Add possibility to draw voxels as boxes.

The colors are set to be the same as the VDB paper, just like for the
tree. They are drawn perfectly, but that'll for the moment.

Move draw settings to its own struct and add some more options.

For now the options control the tolerance for drawing voxels and their
size in the viewport.

Use vertex arrays to draw the VDB tree and its values.

Merge branch 'master' into openvdb

Several fixes and cleanups to the compile process:

- disable exceptions in tbb for cycles due to typeid usage
- cleanup SConscript in intern/openvdb, and make others align with
CMakeLists
- import fixes from gooseberry branch by sergey
- fix compilation error when cycles logging is disabled
- avoid unnecessary includes if building without openvdb

A simple UI for the VDB tree visualization.

Merge branch 'master' into openvdb

Add extra metadatas to the grids:

- set vector type for scalar grids as well
- set vector grids class to GRID_STAGGERED, this might become an option/
function parameter at some point.

Cycles: add support for sampling staggered vector grids.

Cycles: rename openvdb.* files to volume.*

Cycles: style cleanup.