Transparent Standard Surface Shader with Depth

SurfaceShadowCaster.hlsl

Shader "Custom/SurfaceShadowCaster"
{
    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
        _Cutout ("Cutout", Range(0, 1)) = 0.5
    }

    SubShader
    {
        Pass
        {
            Name "ShadowCaster"
            Tags { "LightMode"="ShadowCaster" }

            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #pragma multi_compile_shadowcaster
            #include "UnityCG.cginc"

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

            struct v2f {
                V2F_SHADOW_CASTER;
                float2 uv : TEXCOORD1;
            };

            sampler2D _MainTex;
            float4 _MainTex_ST;
            float _Cutout;

            v2f vert(appdata v)
            {
                v2f o;
                o.uv = TRANSFORM_TEX(v.uv, _MainTex);
                TRANSFER_SHADOW_CASTER(o)
                return o;
            }

            float4 frag( v2f i ) : COLOR
            {
                fixed4 texcol = tex2D( _MainTex, i.uv );
                if (texcol.a < _Cutout)
                {
                    discard;
                }
                SHADOW_CASTER_FRAGMENT(i)
            }
            ENDCG
        }
    }

    SubShader
    {
        Tags { "RenderType"="Transparent" "Queue"="Transparent" }
        LOD 200
        Blend SrcAlpha OneMinusSrcAlpha
        ZWrite On

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

        // 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
    }
    FallBack "Diffuse"
}