Shader "_MyShader/7_Advanced/2_Fresnel"

{

    Properties

    {

        _Color("Color", COLOR) = (1,1,1,1)

            _CubeMap("CubeMap", Cube) = "SkyBox" {}

            _FresnelScale("FresnelScale", Range(0,1.5)) = 0.5

    }

    SubShader

    {

        Tags { "RenderType"="ForwardBase" }



        Pass

        {

            CGPROGRAM

            #pragma vertex vert

            #pragma fragment frag



            #include "UnityCG.cginc"

            #include "Lighting.cginc"

            #include "AutoLight.cginc"



            struct a2v

            {

                float4 vertex : POSITION;

                float3 normal : NORMAL;

            };



            struct v2f

            {

                float4 pos : SV_POSITION;

                float4 worldPos : TEXCOORD1;

                float3 worldNormal : TEXCOORD2;

                float3 worldLight : TEXCOORD3;

                float3 worldView : TEXCOORD4;

                float3 worldReflection : TEXCOORD5;



                SHADOW_COORDS(5)

            };



            fixed4 _Color;

            samplerCUBE _CubeMap;

            float _FresnelScale;



            v2f vert (a2v v)

            {

                v2f o;

                o.pos = mul(UNITY_MATRIX_MVP, v.vertex);



                o.worldPos = mul(_Object2World,v.vertex);



                o.worldNormal = UnityObjectToWorldNormal(v.normal);

                o.worldLight = UnityWorldSpaceLightDir(o.worldPos);

                o.worldView = UnityWorldSpaceViewDir(o.worldPos);



                o.worldReflection = reflect(-o.worldView, o.worldNormal);



                TRANSFER_SHADOW(o);



                return o;

            }



            fixed4 frag (v2f i) : SV_Target

            {

                fixed3 worldNormalDir = normalize(i.worldNormal);

                fixed3 worldLightDir = normalize(i.worldLight);

                fixed3 worldViewDir = normalize(i.worldView);



                fixed3 ambient = UNITY_LIGHTMODEL_AMBIENT.xyz;



                fixed3 diffuseColor = _LightColor0.rgb * _Color.rgb * max(0, dot(worldNormalDir, worldLightDir));



                fixed3 refraction = texCUBE(_CubeMap, i.worldReflection).rgb;



                fixed3 fresnel = _FresnelScale + (1 - _FresnelScale) * pow((1 - dot(worldViewDir, worldNormalDir)), 5);



                UNITY_LIGHT_ATTENUATION(atten, i, i.worldPos);



                fixed3 color = ambient + lerp(diffuseColor, refraction, fresnel) * atten;



                return fixed4(color, 1);

            }

            ENDCG

        }

    }

}