This implements the proposal made in the forum for "shiny" materials -
material can now determine the angle at which the most light is reflected.
Shiny materials might set this lower to approximate a "reflection" effect,
and increase the "spottiness" at the same time. To compensate for the
lack of brightness without light, "emittance" can be used.
Not sure this is the most elegant way to model this - the "proper" way
here would be to have emittance, shading and specular as three separate
light parameters instead of molding one into the other and using the third
to compensate.
Furthermore, this reorganises shaders in a major way: We reduce the
number of shader files down to three, pushing a number of possible
configurations into preprocessor. I believe this should be easier to
understand, which for the moment trumps theoretical extensibility
benefits.
Peter Wortmann