Background attributes are used as fallback in two cases:
1) Non-object light samples (e.g. lamp shaders)
2) Fallback if no implicit object attribute can be found
* std::particle_index
* std::particle_age
* std::particle_lifetime
* std::particle_location
* std::particle_size
* std::particle_velocity
* std::particle_angular_velocity
Just as with SVM the rotation state attribute is currently disabled due to lack of a proper quaternion or matrix type in Cycles nodes.
* std::object_location
* std::object_index
* std::material_index
* std::object_random
Other object-based attributes can be added for particle info in the same way.
Fixes for API changes in OSL RendererServices:
* Added two new required get_matrix methods, from OSL RendererServices (otherwise the constructor fails). The two new matrix methods probably still need an implementation.
* Removed deprecated "get_pointcloud_attr_query" and "pointcloud". There are two new routines for pointclouds, function headers for those are there.
* Removed the (unused) PARTIO code parts from OSL. It was marked as not tested / not working, and due to the api changes here broken for sure. Code is still in svn history if needed.