[Bf-cycles] Question about Oren-Nayar diffuse model

[Yasuhiro Fujii]

Sorry. The original code is wrong.

original:
 nl = max(dot(N, L), 0.0f);
 nv = max(dot(N, E), 0.0f);
 arg_nl = acos(nl);
 arg_nv = acos(nv);
 a = max(arg_nl, arg_nv);
 b = min(arg_nl, arg_nv);
 b *= 0.95f;
 sin_a = sin(a);
 tan_b = tan(b);

-- y.fujii