Features to get the 2nd, 3rd, 4th closest point instead of the closest, and
various distance metrics. No viewport/Eevee support yet.
Patch by Michel Anders, Charlie Jolly and Brecht Van Lommel.
Differential Revision: https://developer.blender.org/D3503
Let's finally delete this code, after 4 years of being unused,
there really is no excuse anymore.
If we decide to extend the procedural textures in SVM, we can do this anytime in the future.
* Simplify default color values, where each component was the same.
* Initialize closures as Null Closure, rather than assigning an existing closure, gets overwritten anyways.
* Moved kernel/osl/nodes to kernel/shaders
* Renamed standard attributes to use geom:, particle:, object: prefixes
* Update stdosl.h to properly reflect the closures we support
* Fix the wrong stdosl.h being used for building shaders
* Add geom:numpolyvertices, geom:trianglevertices, geom:polyvertices attributes
