Stencil Outline Effect

Shader "Outline"
{
    Properties
    {
        _Color("Color", Color) = (1,0,0,1)
        _Thickness("Thickness", float) = 4
        _NoiseTex("Noise Map", 2D) = "white" {}
        _FadeDist("Fade Distance", Range(0, 500)) = 100
        _MinDist("Minimum Fade-In Distance", Range(0,25)) = 10
    }
        SubShader
    {

        Tags{ "Queue" = "Transparent+1" "IgnoreProjector" = "True" "RenderType" = "Transparent" "DisableBatching" = "True" }
        Blend SrcAlpha One
        Cull Back
        ZTest always
        Pass
    {
        Stencil
        {
            Ref 1
            Comp always
            Pass replace
        }

        CGPROGRAM
#pragma vertex vert
#pragma fragment frag
#pragma multi_compile_fog

#include "UnityCG.cginc"

    struct v2g
    {
        float4  pos : SV_POSITION;
        float2  uv : TEXCOORD0;
        float3 viewTangent : TANGENT;
        float3 normals : NORMAL;
    };

    struct g2f
    {
        float4  pos : SV_POSITION;
        float2  uv : TEXCOORD0;
        float3  viewTangent : TANGENT;
        float3  normals : NORMAL;
    };

    v2g vert(appdata_base v)
    {
        v2g OUT;
        OUT.pos = UnityObjectToClipPos(v.vertex);
        OUT.uv = v.texcoord;
        OUT.normals = v.normal;
        OUT.viewTangent = ObjSpaceViewDir(v.vertex);

        return OUT;
    }

    half4 frag(g2f IN) : COLOR
    {
        //Render nothing, since this shader is for a secondary material
        return 0;
    }
        ENDCG
    }
        Pass
    {
        Stencil
        {
            Ref 0
            Comp equal
        }
        CGPROGRAM
#include "UnityCG.cginc"
#pragma target 3.0
#pragma vertex vert
#pragma require geometry
#pragma geometry geom
#pragma fragment frag


    half4 _Color;
    float _Thickness;
    sampler2D _NoiseTex;
    float _FadeDist;
    float _MinDist;
    struct v2g
    {
        float4 pos : SV_POSITION;
        float2 uv : TEXCOORD0;
        float3 viewTangent : TANGENT;
        float3 normals : NORMAL;
        float3 viewDist : TEXCOORD1;
    };
    struct g2f
    {
        float4 pos : SV_POSITION;
        float2 uv : TEXCOORD0;
        float3 viewTangent : TANGENT;
        float3 normals : NORMAL;
        float3 viewDist : TEXCOORD1;
    };

    v2g vert(appdata_base v)
    {
        v2g OUT;
        OUT.pos = UnityObjectToClipPos(v.vertex);
        OUT.uv = v.texcoord;
        OUT.normals = v.normal;
        OUT.viewTangent = ObjSpaceViewDir(v.vertex);
        OUT.viewDist = UnityObjectToViewPos(v.vertex).xyz;
        return OUT;
    }

    void displaceGeo(v2g start, v2g end, inout TriangleStream<g2f> triStream)
    {
        float width = _Thickness / 100;
        float4 parallel = end.pos - start.pos;
        normalize(parallel);
        parallel *= width;

        float4 perpendicular = float4(parallel.y, -parallel.x, 0, 0);
        perpendicular = normalize(perpendicular) * width;
        float4 v1 = start.pos - parallel;
        float4 v2 = end.pos + parallel;

        g2f OUT;

        OUT.pos = v1 - perpendicular;
        OUT.uv = start.uv;
        OUT.viewTangent = start.viewTangent;
        OUT.normals = start.normals;
        OUT.viewDist = start.viewDist;
        triStream.Append(OUT);

        OUT.pos = v1 + perpendicular;
        OUT.viewDist = start.viewDist;
        triStream.Append(OUT);

        OUT.pos = v2 - perpendicular;
        OUT.uv = end.uv;
        OUT.viewTangent = end.viewTangent;
        OUT.normals = end.normals;
        OUT.viewDist = start.viewDist;
        triStream.Append(OUT);

        OUT.pos = v2 + perpendicular;
        OUT.uv = end.uv;
        OUT.viewTangent = end.viewTangent;
        OUT.normals = end.normals;
        OUT.viewDist = start.viewDist;
        triStream.Append(OUT);
    }

    [maxvertexcount(4)]
    void geom(triangle v2g IN[3], inout TriangleStream<g2f> triStream)
    {
        displaceGeo(IN[0],IN[1], triStream);
        displaceGeo(IN[1],IN[2], triStream);
        displaceGeo(IN[2],IN[0], triStream);
    }

    half4 frag(g2f IN) : COLOR
    {
        IN.uv.x += _Time;
        IN.uv.y += _Time;
        fixed4 col = tex2D(_NoiseTex, IN.uv) * _Color;
        col.a = saturate((length(IN.viewDist) - _MinDist) / _FadeDist);
        clip(col.a - 0.001);
        return col;
    }
        ENDCG
    }
    }
        FallBack "Diffuse"
}