Standard Shader - 2 Sided (cull off) - Also, 2 Sided Standard Surface Shader with Fixed Normals

Standard-2Sided-FixNormals.shader

// 2 sided standard surface shader (using 2 passes), with fixed normals for flipped faces

Shader "Custom/TwoSided (FixedNormals)"
{
    Properties
    {
        _Color ("Color", Color) = (1,1,1,1)
        _MainTex ("Albedo (RGB)", 2D) = "white" {}
        _Glossiness ("Smoothness", Range(0,1)) = 0.5
        _Metallic ("Metallic", Range(0,1)) = 0.0
    }
    SubShader
	{

		Tags { "RenderType" = "Opaque" }
		LOD 200
		Cull Back

		CGPROGRAM
		// Physically based Standard lighting model, and enable shadows on all light types
		#pragma surface surf Standard fullforwardshadows

		// Use shader model 3.0 target, to get nicer looking lighting
		#pragma target 3.0

		sampler2D _MainTex;

		struct Input
		{
			float2 uv_MainTex;
		};

		half _Glossiness;
		half _Metallic;
		fixed4 _Color;

		// Add instancing support for this shader. You need to check 'Enable Instancing' on materials that use the shader.
		// See https://docs.unity3d.com/Manual/GPUInstancing.html for more information about instancing.
		// #pragma instancing_options assumeuniformscaling
		UNITY_INSTANCING_BUFFER_START(Props)
			// put more per-instance properties here
		UNITY_INSTANCING_BUFFER_END(Props)

		void surf(Input IN, inout SurfaceOutputStandard o)
		{
			// Albedo comes from a texture tinted by color
			fixed4 c = tex2D(_MainTex, IN.uv_MainTex) * _Color;
			o.Albedo = c.rgb;
			// Metallic and smoothness come from slider variables
			o.Metallic = _Metallic;
			o.Smoothness = _Glossiness;
			o.Alpha = c.a;
		}
		ENDCG

		// 2nd pass to fix flipped normals
		Tags{ "RenderType" = "Opaque" }
		LOD 200
		Cull Front

		CGPROGRAM
		// Physically based Standard lighting model, and enable shadows on all light types
		#pragma surface surf Standard fullforwardshadows
		#pragma vertex vert

		// Use shader model 3.0 target, to get nicer looking lighting
		#pragma target 3.0

		sampler2D _MainTex;

		struct Input
		{
			float2 uv_MainTex;
		};

		half _Glossiness;
		half _Metallic;
		fixed4 _Color;

		// Add instancing support for this shader. You need to check 'Enable Instancing' on materials that use the shader.
		// See https://docs.unity3d.com/Manual/GPUInstancing.html for more information about instancing.
		// #pragma instancing_options assumeuniformscaling
		UNITY_INSTANCING_BUFFER_START(Props)
		// put more per-instance properties here
		UNITY_INSTANCING_BUFFER_END(Props)

		void vert(inout appdata_full v, out Input o) {
			UNITY_INITIALIZE_OUTPUT(Input, o);
			v.normal = -v.normal;
		}

		void surf(Input IN, inout SurfaceOutputStandard o)
		{
			// Albedo comes from a texture tinted by color
			fixed4 c = tex2D(_MainTex, IN.uv_MainTex) * _Color;
			o.Albedo = c.rgb;
			// Metallic and smoothness come from slider variables
			o.Metallic = _Metallic;
			o.Smoothness = _Glossiness;
			o.Alpha = c.a;
		}
		ENDCG


	}
    FallBack "Diffuse"
}

Standard-2Sided.shader

// Unity built-in shader source. Copyright (c) 2016 Unity Technologies. MIT license (see license.txt)

Shader "Standard 2-Sided"
{
	Properties
	{
		_Color("Color", Color) = (1,1,1,1)
		_MainTex("Albedo", 2D) = "white" {}
		
		_Cutoff("Alpha Cutoff", Range(0.0, 1.0)) = 0.5

		_Glossiness("Smoothness", Range(0.0, 1.0)) = 0.5
		_GlossMapScale("Smoothness Scale", Range(0.0, 1.0)) = 1.0
		[Enum(Metallic Alpha,0,Albedo Alpha,1)] _SmoothnessTextureChannel ("Smoothness texture channel", Float) = 0

		[Gamma] _Metallic("Metallic", Range(0.0, 1.0)) = 0.0
		_MetallicGlossMap("Metallic", 2D) = "white" {}

		[ToggleOff] _SpecularHighlights("Specular Highlights", Float) = 1.0
		[ToggleOff] _GlossyReflections("Glossy Reflections", Float) = 1.0

		_BumpScale("Scale", Float) = 1.0
		_BumpMap("Normal Map", 2D) = "bump" {}

		_Parallax ("Height Scale", Range (0.005, 0.08)) = 0.02
		_ParallaxMap ("Height Map", 2D) = "black" {}

		_OcclusionStrength("Strength", Range(0.0, 1.0)) = 1.0
		_OcclusionMap("Occlusion", 2D) = "white" {}

		_EmissionColor("Color", Color) = (0,0,0)
		_EmissionMap("Emission", 2D) = "white" {}
		
		_DetailMask("Detail Mask", 2D) = "white" {}

		_DetailAlbedoMap("Detail Albedo x2", 2D) = "grey" {}
		_DetailNormalMapScale("Scale", Float) = 1.0
		_DetailNormalMap("Normal Map", 2D) = "bump" {}

		[Enum(UV0,0,UV1,1)] _UVSec ("UV Set for secondary textures", Float) = 0


		// Blending state
		[HideInInspector] _Mode ("__mode", Float) = 0.0
		[HideInInspector] _SrcBlend ("__src", Float) = 1.0
		[HideInInspector] _DstBlend ("__dst", Float) = 0.0
		[HideInInspector] _ZWrite ("__zw", Float) = 1.0
	}

	CGINCLUDE
		#define UNITY_SETUP_BRDF_INPUT MetallicSetup
	ENDCG

	SubShader
	{
		Tags { "RenderType"="Opaque" "PerformanceChecks"="False" }
		LOD 300
	

		// ------------------------------------------------------------------
		//  Base forward pass (directional light, emission, lightmaps, ...)
		Pass
		{
			Name "FORWARD" 
			Tags { "LightMode" = "ForwardBase" }

			Blend [_SrcBlend] [_DstBlend]
			ZWrite [_ZWrite]
			
			Cull Off

			CGPROGRAM
			#pragma target 3.0

			// -------------------------------------

			#pragma shader_feature _NORMALMAP
			#pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
			#pragma shader_feature _EMISSION
			#pragma shader_feature _METALLICGLOSSMAP
			#pragma shader_feature ___ _DETAIL_MULX2
			#pragma shader_feature _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
			#pragma shader_feature _ _SPECULARHIGHLIGHTS_OFF
			#pragma shader_feature _ _GLOSSYREFLECTIONS_OFF
			#pragma shader_feature _PARALLAXMAP

			#pragma multi_compile_fwdbase
			#pragma multi_compile_fog
			#pragma multi_compile_instancing

			#pragma vertex vertBase
			#pragma fragment fragBase
			#include "UnityStandardCoreForward.cginc"

			ENDCG
		}
		// ------------------------------------------------------------------
		//  Additive forward pass (one light per pass)
		Pass
		{
			Name "FORWARD_DELTA"
			Tags { "LightMode" = "ForwardAdd" }
			Blend [_SrcBlend] One
			Fog { Color (0,0,0,0) } // in additive pass fog should be black
			ZWrite Off
			ZTest LEqual
			Cull Off

			CGPROGRAM
			#pragma target 3.0

			// -------------------------------------


			#pragma shader_feature _NORMALMAP
			#pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
			#pragma shader_feature _METALLICGLOSSMAP
			#pragma shader_feature _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
			#pragma shader_feature _ _SPECULARHIGHLIGHTS_OFF
			#pragma shader_feature ___ _DETAIL_MULX2
			#pragma shader_feature _PARALLAXMAP

			#pragma multi_compile_fwdadd_fullshadows
			#pragma multi_compile_fog

			#pragma vertex vertAdd
			#pragma fragment fragAdd
			#include "UnityStandardCoreForward.cginc"

			ENDCG
		}
		// ------------------------------------------------------------------
		//  Shadow rendering pass
		Pass {
			Name "ShadowCaster"
			Tags { "LightMode" = "ShadowCaster" }

			ZWrite On ZTest LEqual

			CGPROGRAM
			#pragma target 3.0

			// -------------------------------------


			#pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
			#pragma shader_feature _METALLICGLOSSMAP
			#pragma shader_feature _PARALLAXMAP
			#pragma multi_compile_shadowcaster
			#pragma multi_compile_instancing

			#pragma vertex vertShadowCaster
			#pragma fragment fragShadowCaster

			#include "UnityStandardShadow.cginc"

			ENDCG
		}
		// ------------------------------------------------------------------
		//  Deferred pass
		Pass
		{
			Name "DEFERRED"
			Tags { "LightMode" = "Deferred" }

			CGPROGRAM
			#pragma target 3.0
			#pragma exclude_renderers nomrt


			// -------------------------------------

			#pragma shader_feature _NORMALMAP
			#pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
			#pragma shader_feature _EMISSION
			#pragma shader_feature _METALLICGLOSSMAP
			#pragma shader_feature _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
			#pragma shader_feature _ _SPECULARHIGHLIGHTS_OFF
			#pragma shader_feature ___ _DETAIL_MULX2
			#pragma shader_feature _PARALLAXMAP

			#pragma multi_compile_prepassfinal
			#pragma multi_compile_instancing

			#pragma vertex vertDeferred
			#pragma fragment fragDeferred

			#include "UnityStandardCore.cginc"

			ENDCG
		}

		// ------------------------------------------------------------------
		// Extracts information for lightmapping, GI (emission, albedo, ...)
		// This pass it not used during regular rendering.
		Pass
		{
			Name "META" 
			Tags { "LightMode"="Meta" }

			Cull Off

			CGPROGRAM
			#pragma vertex vert_meta
			#pragma fragment frag_meta

			#pragma shader_feature _EMISSION
			#pragma shader_feature _METALLICGLOSSMAP
			#pragma shader_feature _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
			#pragma shader_feature ___ _DETAIL_MULX2
			#pragma shader_feature EDITOR_VISUALIZATION

			#include "UnityStandardMeta.cginc"
			ENDCG
		}
	}

	SubShader
	{
		Tags { "RenderType"="Opaque" "PerformanceChecks"="False" }
		LOD 150

		// ------------------------------------------------------------------
		//  Base forward pass (directional light, emission, lightmaps, ...)
		Pass
		{
			Name "FORWARD" 
			Tags { "LightMode" = "ForwardBase" }

			Blend [_SrcBlend] [_DstBlend]
			ZWrite [_ZWrite]
			Cull Off

			CGPROGRAM
			#pragma target 2.0
			
			#pragma shader_feature _NORMALMAP
			#pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
			#pragma shader_feature _EMISSION 
			#pragma shader_feature _METALLICGLOSSMAP 
			#pragma shader_feature _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
			#pragma shader_feature _ _SPECULARHIGHLIGHTS_OFF
			#pragma shader_feature _ _GLOSSYREFLECTIONS_OFF
			// SM2.0: NOT SUPPORTED shader_feature ___ _DETAIL_MULX2
			// SM2.0: NOT SUPPORTED shader_feature _PARALLAXMAP

			#pragma skip_variants SHADOWS_SOFT DIRLIGHTMAP_COMBINED

			#pragma multi_compile_fwdbase
			#pragma multi_compile_fog

			#pragma vertex vertBase
			#pragma fragment fragBase
			#include "UnityStandardCoreForward.cginc"

			ENDCG
		}
		// ------------------------------------------------------------------
		//  Additive forward pass (one light per pass)
		Pass
		{
			Name "FORWARD_DELTA"
			Tags { "LightMode" = "ForwardAdd" }
			Blend [_SrcBlend] One
			Fog { Color (0,0,0,0) } // in additive pass fog should be black
			ZWrite Off
			ZTest LEqual
			Cull Off
			
			CGPROGRAM
			#pragma target 2.0

			#pragma shader_feature _NORMALMAP
			#pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
			#pragma shader_feature _METALLICGLOSSMAP
			#pragma shader_feature _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
			#pragma shader_feature _ _SPECULARHIGHLIGHTS_OFF
			#pragma shader_feature ___ _DETAIL_MULX2
			// SM2.0: NOT SUPPORTED shader_feature _PARALLAXMAP
			#pragma skip_variants SHADOWS_SOFT
			
			#pragma multi_compile_fwdadd_fullshadows
			#pragma multi_compile_fog
			
			#pragma vertex vertAdd
			#pragma fragment fragAdd
			#include "UnityStandardCoreForward.cginc"

			ENDCG
		}
		// ------------------------------------------------------------------
		//  Shadow rendering pass
		Pass {
			Name "ShadowCaster"
			Tags { "LightMode" = "ShadowCaster" }
			
			ZWrite On ZTest LEqual

			CGPROGRAM
			#pragma target 2.0

			#pragma shader_feature _ _ALPHATEST_ON _ALPHABLEND_ON _ALPHAPREMULTIPLY_ON
			#pragma shader_feature _METALLICGLOSSMAP
			#pragma skip_variants SHADOWS_SOFT
			#pragma multi_compile_shadowcaster

			#pragma vertex vertShadowCaster
			#pragma fragment fragShadowCaster

			#include "UnityStandardShadow.cginc"

			ENDCG
		}

		// ------------------------------------------------------------------
		// Extracts information for lightmapping, GI (emission, albedo, ...)
		// This pass it not used during regular rendering.
		Pass
		{
			Name "META" 
			Tags { "LightMode"="Meta" }

			Cull Off

			CGPROGRAM
			#pragma vertex vert_meta
			#pragma fragment frag_meta

			#pragma shader_feature _EMISSION
			#pragma shader_feature _METALLICGLOSSMAP
			#pragma shader_feature _ _SMOOTHNESS_TEXTURE_ALBEDO_CHANNEL_A
			#pragma shader_feature ___ _DETAIL_MULX2
			#pragma shader_feature EDITOR_VISUALIZATION

			#include "UnityStandardMeta.cginc"
			ENDCG
		}
	}


	FallBack "VertexLit"
	CustomEditor "StandardShaderGUI"
}

Thank You!

2020 and it's still a great shader. I have Unity 2019 but like using Unity 2018 and the 2018 shader I tried to add CULL OFF to the shader but it doesn't work for some reason. It used to work with Unity 5 shaders. Surprised Unity still hasn't made it easier to turn backface culling off, or at least provide a default shader that has culling turned off (maybe it does? I haven't found one yet). It's a useful shader for clothing, hair and capes, etc. Thanks.

Perfect. Thank You!

Great!

Love you!

only if this engine had anything good in it they prefer engine preformance over anything else everything is code engine sucks balls