OBD talk:OBLS

It would look like Oni used to support rather advanced lighting setups. Spatial distributions were not limited to point light sources, and allowed area lights (i.e., whole polygon surfaces emitting light with a uniform density) as well as "linear" distributions of light (something like a zero-thickness neon tube). As for the angular distribution, it could be either diffuse (light radiated in all directions from the source) or spot-like, determined by a "beam angle" (size of the cone where the radiated light intensity is maximal/nominal) and a "field angle" (size of the cone beyond which there is no light radiated at all), supposedly with linear falloff in-between. Although the beam and field angles only make sense for spot lights (and thus were probably unavailable for the "diffuse" flavor of angular distribution), it is not obvious from the dialog whether the "spot" flavor of angular distribution was available for all the flavors of the spatial distribution, or only for "point". On another note, there are no separate fields for specifying the spatial extent of linear or area lights, so it must be assumed that the OBLS were box-like entities placed in the world (with arbitrary translation, rotation, and scale), with one axis interpreted as the normal (central axis of a spot-like angular distribution if any), and the other two axes serving (via their respective scaling amounts) as the spatial extent for linear and area flavors. For area lights, emission was probably limited only to the forward-facing side of the light source object (rectangle). --geyser (talk) 00:53, 29 August 2020 (CEST)