FXAA + Fiddling

Signed-off-by: Robear Selwans <robear.selwans@outlook.com>

assets/shaders/_builtins/PBR.glsl

@@ -37,4 +37,9 @@ vec3 fresnelSchlick(float cosTheta, vec3 F0)
     return F0 + (1.0 - F0) * pow(1.0 - cosTheta, 5.0);
 }
 
+vec3 fresnelSchlickRoughness(float cosTheta, vec3 F0, float roughness)
+{
+    return F0 + (max(vec3(1.0 - roughness), F0) - F0) * pow(max(1.0 - cosTheta, 0.0), 5.0);
+}
+
 #endif