[Bf-cycles] build with OSL support

[Brecht Van Lommel]

On Fri, Nov 11, 2011 at 10:53 AM, Yasuhiro Fujii
<y-fujii at mimosa-pudica.net> wrote:
> I want to propose simpler ones:
>  0<= sigma <= 1
>  A = 1.0f - 0.5f * sigma;
>  B = 0.5f * sigma;
> which are much more useful for me. they have no magic numbers and
> behave straightforwardly.
> Of course, this form is artificial. however, original form also
> doesn't seem to have strong theoretical reason. It seems to be chosen
> by numerical experiment, not by the straight approximation.
>
> What do you think about it?

Looks like a good change, I've tried to keep things in 0..1 range in
other places too.

Brecht.