Shader "Custom/Outline" {
    Properties {
        _MainTex ("MainTex", 2D) = "white" {}
        _Outline ("_Outline", Range(1,5)) = 0
        _OutlineClr ("Outline Color", Color) = (1, 1, 0, 1)
    }
    SubShader {
        Pass {
            Tags { "RenderType"="Opaque" }
            ZWrite Off

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

            half _Outline;
            half4 _OutlineClr;

            struct appdata
            {
                half4 vertex : POSITION;
                half4 normal : NORMAL;
                UNITY_VERTEX_INPUT_INSTANCE_ID
            };

            struct v2f {
                half4 pos : SV_POSITION;
                UNITY_VERTEX_INPUT_INSTANCE_ID
            };

            half4 vert(appdata v) : SV_POSITION {
                v2f o;
                v.vertex *= _Outline;
                o.pos = UnityObjectToClipPos(v.vertex);
                return o.pos;
            }

            half4 frag(v2f i) : COLOR {
                return _OutlineClr;
            }

            ENDCG
        }

        CGPROGRAM
        #pragma surface surf Lambert noforwardadd exclude_path:prepass nolightmap
        sampler2D _MainTex;

        struct Input {
            half2 uv_MainTex;
        };

        void surf(Input IN, inout SurfaceOutput o) {
            o.Albedo = tex2D(_MainTex, IN.uv_MainTex);
        }

        ENDCG
    }
    FallBack "Diffuse"
}