Use a branchless diffuse function

Roughness is never used for the diffuse so the Oren-Nayar function with
branching is not needed.

Task-number: QT3DS-2010
Change-Id: I8d81adabbf254cb5af4d7ae6d6aec9da8ad89bc5
Reviewed-by: Janne Koskinen <janne.p.koskinen@qt.io>
Reviewed-by: Antti Määttä <antti.maatta@qt.io>
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>

1 files changed, 5 insertions, 0 deletions

diff --git a/res/effectlib/funclambertReflectionBSDF.glsllib b/res/effectlib/funclambertReflectionBSDF.glsllib
new file mode 100644
index 0000000..07278cc
--- /dev/null
+++ b/res/effectlib/funclambertReflectionBSDF.glsllib
@@ -0,0 +1,5 @@
+vec4 lambertReflectionBSDF( in vec3 N, in vec3 L, in vec3 lightDiffuse )
+{
+  float cosThetaI = max( 0.0, dot( N, L ) );
+  return vec4( cosThetaI * lightDiffuse, 1.0 );
+}