ShadowMapping With Outline

Shader "Unlit/recieveShadowMapWithOutline"

{
    Properties
    {
        _MainTex ("Texture", 2D) = "white" {}
    }
    SubShader
    {
        Tags { "LightMode" = "ForwardBase"
                "RenderType"="Opaque"
    }
        LOD 100

        Pass
        {
            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            // make fog work
            #pragma multi_compile_fog
#define SHADOWS_SCREEN
            #include "AutoLight.cginc"
            #include "UnityCG.cginc"

            struct appdata
            {
                float4 vertex : POSITION;
                float2 uv : TEXCOORD0;
            };

            struct v2f
            {
                float2 uv : TEXCOORD0;
                UNITY_FOG_COORDS(1)
                SHADOW_COORDS(5)
                float4 pos : SV_POSITION;
            };

            sampler2D _MainTex;
            float4 _MainTex_ST;

            v2f vert (appdata v)
            {
                v2f o;
                o.pos = UnityObjectToClipPos(v.vertex);
                o.uv = TRANSFORM_TEX(v.uv, _MainTex);
                TRANSFER_SHADOW(o);
                UNITY_TRANSFER_FOG(o,o.pos);
                return o;
            }

            float sampleEdge(sampler2D tex, float2 uv, float Offset) {

                float mi = 1000.;
                float ma = -100.;
                float x, y;
                for (y = -1.; y <= 1.; y += 1.0)
                {
                    for (x = -1.; x <= 1.; x += 1.0)
                    {
                        float offsets = Offset / _ScreenParams.xy;

                        float v = tex2D(tex, uv + float2(x, y)*offsets );
                        mi = min(v, mi);
                        ma = max(v, ma);
                    }
                }

                return abs(ma - mi);
            }

            fixed4 frag (v2f i) : SV_Target
            {
                // sample the texture
                fixed4 col = tex2D(_MainTex, i.uv);
            float3 shadowCoord = i._ShadowCoord.xyz / i._ShadowCoord.w;
            float shadowmap = tex2D(_ShadowMapTexture, shadowCoord.xy);
            float thickness = 20.;
            float e = sampleEdge(_ShadowMapTexture, shadowCoord.xy, thickness / i._ShadowCoord.w);
            col.xyz = lerp(pow(col.xyz, 3.6)*0.45, col.xyz, shadowmap);
            col.xyz = lerp(col.xyz, float3(.1,0.2,0.3), e);
            UNITY_APPLY_FOG(i.fogCoord, col);
                return col;
            }
            ENDCG
        }
    }   FallBack "VertexLit"
}