Unity Shader Example 18 (Fresnel)

Shader "Fresnel/Test"
{
Properties
{
_MainTex ("Base (RGB)", 2D) = "white" {}
_Fresnel0 ("fresnel0", Float) = 0.1
_Color ("Rim Color", Color) = (1.0, 1.0, 1.0, 1.0)
}
SubShader
{
Pass
{
CGPROGRAM
#include "UnityCG.cginc"
#pragma vertex vert
#pragma fragment frag

uniform sampler2D _MainTex;
uniform float4 _MainTex_ST;
uniform float4 _Color;
uniform float _Fresnel0;

struct vIN
{
float4 vertex : POSITION;
float3 normal : NORMAL;
float2 texcoord : TEXCOORD0;
};

struct vOUT
{
float4 pos : SV_POSITION;
float2 uv : TEXCOORD0;
float3 viewDir : TEXCOORD1;

};

vOUT vert(vIN v)
{
vOUT o;
o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
o.uv = v.texcoord;
o.viewDir = WorldSpaceViewDir(v.vertex);

return o;
}

float4 frag(vOUT i) :  COLOR
{
float4 col = tex2D(_MainTex, i.uv.xy * _MainTex_ST.xy + _MainTex_ST.zw);

fixed3 normViewDir = normalize(i.viewDir);

half nDotView = dot(fixed3(0, 1, 0), normViewDir);

half fresnel = _Fresnel0 + (1.0 - _Fresnel0) * pow( (1.0 - nDotView ), 5.0);

fresnel = max(0.0, fresnel - .1);

return lerp(col,_Color, fresnel);

}

ENDCG
}
}
FallBack "Diffuse"
}