Hello,
I am struggling to add fresnel coefficient to standard Surface shader in Unity 3.0 (to Reflective bumped specular).
I must admit, I am not very good at shading - so I googled a formula, applied it, but the results don’t look much different from an original shader.
Could any of Gurus help me out with that and give a hint where I might be wrong\incorrect?
Thanks! 
Shader "Reflective/Bumped Specular Fresnel" {
Properties {
_Color ("Main Color", Color) = (1,1,1,1)
_SpecColor ("Specular Color", Color) = (0.5,0.5,0.5,1)
_Shininess ("Shininess", Range (0.01, 1)) = 0.078125
_ReflectColor ("Reflection Color", Color) = (1,1,1,0.5)
_MainTex ("Base (RGB) RefStrGloss (A)", 2D) = "white" {}
_Cube ("Reflection Cubemap", Cube) = "" { TexGen CubeReflect }
_BumpMap ("Normalmap", 2D) = "bump" {}
_Fresnel("Fresnel Coef.", Range (0.01, 0.7)) = 0.35
}
SubShader {
Tags { "RenderType"="Opaque" }
LOD 400
CGPROGRAM
#pragma surface surf BlinnPhong
#pragma target 3.0
sampler2D _MainTex;
sampler2D _BumpMap;
samplerCUBE _Cube;
float4 _Color;
float4 _ReflectColor;
float _Shininess;
float _Fresnel;
struct Input {
float2 uv_MainTex;
float2 uv_BumpMap;
//float3 normal;
float3 viewDir;
float3 worldRefl;
INTERNAL_DATA
};
//taken from somewhere in internet
float fresnel(float VdotN, float eta)
{
float sqr_eta = eta * eta; // square of IOR
float etaCos = eta * VdotN; // η·cos(Θ)
float sqr_etaCos = etaCos*etaCos; // squared
float one_minSqrEta = 1.0 - sqr_eta; // 1 – η2
float value = etaCos - sqrt(one_minSqrEta + sqr_etaCos);
value *= value / one_minSqrEta; // square and divide by 1 – η2
return min(1.0, value * value); // square again
}
//float fFresnel = fresnel(dot(vViewNormal, vNormalWS), indexOfRefraction);
void surf (Input IN, inout SurfaceOutput o) {
half4 tex = tex2D(_MainTex, IN.uv_MainTex);
half4 c = tex * _Color;
o.Albedo = c.rgb;
o.Gloss = tex.a;
o.Specular = _Shininess;
o.Normal = UnpackNormal(tex2D(_BumpMap, IN.uv_BumpMap));
float3 worldRefl = WorldReflectionVector (IN, o.Normal);
half4 reflcol = texCUBE (_Cube, worldRefl);
reflcol *= tex.a;
//reflcol = lerp(c, reflcol, fresnel(worldRefl, _Fresnel));
reflcol = lerp(c, reflcol, fresnel(dot(IN.viewDir,o.Normal), _Fresnel));
o.Emission = reflcol.rgb * _ReflectColor.rgb;
o.Alpha = reflcol.a * _ReflectColor.a;
}
ENDCG
}
FallBack "Reflective/Bumped Diffuse"
}