SL-17703: PBR: Move IOR calcF0() to deferred utils

1 files changed, 17 insertions, 0 deletions

diff --git a/indra/newview/app_settings/shaders/class1/deferred/deferredUtil.glsl b/indra/newview/app_settings/shaders/class1/deferred/deferredUtil.glsl
index bb1265802a..8a3eb39ae7 100644
--- a/indra/newview/app_settings/shaders/class1/deferred/deferredUtil.glsl
+++ b/indra/newview/app_settings/shaders/class1/deferred/deferredUtil.glsl
@@ -298,6 +298,23 @@ vec3 hue_to_rgb(float hue)
 
 // PBR Utils
 
+// ior Index of Refraction, normally 1.5
+// returns reflect0
+float calcF0(float ior)
+{
+    float f0 = (1.0 - ior) / (1.0 + ior);
+    return f0 * f0;
+}
+
+vec3 fresnel(float vh, vec3 f0, vec3 f90 )
+{
+    float x  = 1.0 - abs(vh);
+    float x2 = x*x;
+    float x5 = x2*x2*x;
+    vec3  fr = f0 + (f90 - f0)*x5;
+    return fr;
+}
+
 vec3 fresnelSchlick( vec3 reflect0, vec3 reflect90, float vh)
 {
     return reflect0 + (reflect90 - reflect0) * pow(clamp(1.0 - vh, 0.0, 1.0), 5.0);