Traditional subscattering

Shader "Custom/Translucent" {

    Properties {
        _MainTex ("Base (RGB)", 2D) = "white" {}
        _BumpMap ("Normal (Normal)", 2D) = "bump" {}
        _Color ("Main Color", Color) = (1,1,1,1)
        _SpecColor ("Specular Color", Color) = (0.5, 0.5, 0.5, 1)
        _Shininess ("Shininess", Range (0.03, 1)) = 0.078125

        //_Thickness = Thickness texture (invert normals, bake AO).
        //_Power = "Sharpness" of translucent glow.
        //_Distortion = Subsurface distortion, shifts surface normal, effectively a refractive index.
        //_Scale = Multiplier for translucent glow - should be per-light, really.
        //_SubColor = Subsurface colour.
        _Thickness ("Thickness (R)", 2D) = "bump" {}
        _Power ("Subsurface Power", Float) = 1.0
        _Distortion ("Subsurface Distortion", Float) = 0.0
        _Scale ("Subsurface Scale", Float) = 0.5
        _SubColor ("Subsurface Color", Color) = (1.0, 1.0, 1.0, 1.0)
    }

    SubShader {
        Tags { "RenderType"="Opaque" }
        LOD 200

        CGPROGRAM
        #pragma surface surf Translucent
        #pragma exclude_renderers flash

        sampler2D _MainTex, _BumpMap, _Thickness;
        float _Scale, _Power, _Distortion;
        fixed4 _Color, _SubColor;
        half _Shininess;

        struct Input {
            float2 uv_MainTex;
        };

        void surf (Input IN, inout SurfaceOutput o) {
            fixed4 tex = tex2D(_MainTex, IN.uv_MainTex);
            o.Albedo = tex.rgb * _Color.rgb;
            o.Alpha = tex2D(_Thickness, IN.uv_MainTex).r;
            o.Gloss = tex.a;
            o.Specular = _Shininess;
            o.Normal = UnpackNormal(tex2D(_BumpMap, IN.uv_MainTex));
        }

        inline fixed4 LightingTranslucent (SurfaceOutput s, fixed3 lightDir, fixed3 viewDir, fixed atten)
        {       
            // You can remove these two lines,
            // to save some instructions. They're just
            // here for visual fidelity.
            viewDir = normalize ( viewDir );
            lightDir = normalize ( lightDir );

            // Translucency.
            half3 transLightDir = lightDir + s.Normal * _Distortion;
            float transDot = pow ( max (0, dot ( viewDir, -transLightDir ) ), _Power ) * _Scale;
            fixed3 transLight = (atten * 2) * ( transDot ) * s.Alpha * _SubColor.rgb;
            fixed3 transAlbedo = s.Albedo * _LightColor0.rgb * transLight;

            // Regular BlinnPhong.
            half3 h = normalize (lightDir + viewDir);
            fixed diff = max (0, dot (s.Normal, lightDir));
            float nh = max (0, dot (s.Normal, h));
            float spec = pow (nh, s.Specular*128.0) * s.Gloss;
            fixed3 diffAlbedo = (s.Albedo * _LightColor0.rgb * diff + _LightColor0.rgb * _SpecColor.rgb * spec) * (atten * 2);

            // Add the two together.
            fixed4 c;
            c.rgb = diffAlbedo + transAlbedo;
            c.a = _LightColor0.a * _SpecColor.a * spec * atten;
            return c;
        }

        ENDCG
    }
    FallBack "Bumped Diffuse"
}