
240 15. Deferred Shading in Luma
as heat, resulting in no diuse response. Taking advantage of this parametric coupling, color
is conditionally interpreted as albedo or specular color, based on the metallic Boolean. In
the case of metallic surfaces, albedo is hard-coded as zero. In the case of nonmetallic sur-
faces, specular color is hard-coded at (0.04, 0.04, 0.04), a common value in the plausible range
[Homan10; Lagarde 11]. We nd the slight loss in control well worth the savings in g-buer
storage. Further, this coupling makes it challenging for artists to create implausible architec-
tural materials: a fundamental principle of physica ...