Two-sided shader - shadow problem

[Killstar]

Hi
Anyone knows how to fix shadow sorting? I changed shader AlphaTest-BumpSpec by adding "Cull Off"

Shader "2-sided Bumped Specular" {
Properties {
    _Color ("Main Color", Color) = (1,1,1,1)
    _SpecColor ("Specular Color", Color) = (0.5, 0.5, 0.5, 0)
    _Shininess ("Shininess", Range (0.01, 10)) = 0.078125
    _MainTex ("Base (RGB) TransGloss (A)", 2D) = "white" {}
    _BumpMap ("Normalmap", 2D) = "bump" {}
    _Cutoff ("Alpha cutoff", Range(0,1)) = 0.5
}
 
SubShader {
    Tags {"Queue"="AlphaTest" "IgnoreProjector"="True" "RenderType"="TransparentCutout"}
    LOD 400
    Cull Off
    
CGPROGRAM
#pragma surface surf BlinnPhong alphatest:_Cutoff
 
sampler2D _MainTex;
sampler2D _BumpMap;
fixed4 _Color;
half _Shininess;
 
struct Input {
    float2 uv_MainTex;
    float2 uv_BumpMap;
};
 
void surf (Input IN, inout SurfaceOutput o) {
    fixed4 tex = tex2D(_MainTex, IN.uv_MainTex);
    o.Albedo = tex.rgb * _Color.rgb;
    o.Gloss = tex.rgb * _Color.rgb;
    o.Alpha = tex.a * _Color.a;
    o.Specular = _Shininess;
    o.Normal = UnpackNormal(tex2D(_BumpMap, IN.uv_BumpMap));
}
ENDCG
}
 
FallBack "Transparent/Cutout/VertexLit"
}

[Jessy]

Why would you think having culling off would work for something that takes lighting?

http://danielbrauer.com/files/archive-mar-2011.html

[Killstar]

I did not think. I do not know much about programming, so I was looking for help

[Killstar]

"...There is an easy way around this, which is to split the shader into two passes. The first pass uses Cull Back, and treats each normal as usual. The second pass uses Cull Front, and inverts each normal in the vertex program. Now we have a shader that renders both sides of each triangle with correct lighting..."

How to do it?

[Andrew_atl]

"...There is an easy way around this, which is to split the shader into two passes. The first pass uses Cull Back, and treats each normal as usual. The second pass uses Cull Front, and inverts each normal in the vertex program. Now we have a shader that renders both sides of each triangle with correct lighting..."

How to do it?

Read to the end of the article. *Hint* you won't need to learn how to do it.