A simple surface shader for Unity which honours a specific stencil buffer value

UnityStencilledObject.shader

Shader "Custom/Stencilled" {
	Properties {
		_StencilMask("Stencil mask", Int) = 0
		_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

		Stencil {
			Ref[_StencilMask]
			Comp equal
			Pass keep
			Fail keep
		}

		CGPROGRAM
		#pragma surface surf Standard fullforwardshadows
		#pragma target 3.0

		sampler2D _MainTex;

		struct Input {
			float2 uv_MainTex;
		};

		half _Glossiness;
		half _Metallic;
		fixed4 _Color;

		void surf (Input IN, inout SurfaceOutputStandard o) {
			fixed4 c = tex2D(_MainTex, IN.uv_MainTex) * _Color;
			o.Albedo = c.rgb;
			o.Metallic = _Metallic;
			o.Smoothness = _Glossiness;
			o.Alpha = c.a;
		}
		ENDCG
	}
	FallBack "Diffuse"
}