Shader "Custom/wMaillageShader"
{
    Properties
    {
		_MainTex("Texture", 2D) = "white" {}
		_Color("Color", Color) = (1,1,1,1)
		_Threshold("Threshold", float) = 0.01

		_EdgeColor("Edge color", Color) = (1,0,0,1)

		_Glossiness("Smoothness", Range(0,1)) = 0.5
		_Metallic("Metallic", Range(0,1)) = 0.0
    }
    SubShader
    {
        Cull Off ZWrite Off ZTest Always
		Tags { "RenderType" = "Opaque" }
        Pass

		{

			CGPROGRAM

			#pragma vertex vert

			#pragma fragment frag 
			

			#include "UnityCG.cginc"

			struct appdata

			{

				float4 vertex : POSITION;

				float2 uv : TEXCOORD0;

			};

			struct v2f

			{

				float2 uv : TEXCOORD0;

				float4 vertex : SV_POSITION;

			};

			sampler2D _CameraDepthNormalsTexture;
			float4 _MainTex_ST;

			v2f vert(appdata v)

			{

				v2f o;

				o.vertex = UnityObjectToClipPos(v.vertex);

				o.uv = TRANSFORM_TEX(v.uv, _MainTex);

				return o;

			}

			sampler2D _MainTex;

			float4 _MainTex_TexelSize;

			float _Threshold;

			fixed4 _EdgeColor;

			float4 GetPixelValue(in float2 uv) {

				half3 normal;

				float depth;

				DecodeDepthNormal(tex2D(_CameraDepthNormalsTexture, uv), depth, normal);

				return fixed4(normal, depth);

			}

			fixed4 frag(v2f i) : SV_Target

			{

				fixed4 col = tex2D(_MainTex, i.uv);

				fixed4 orValue = GetPixelValue(i.uv);

				float2 offsets[8] = {

					float2(-1, -1),

					float2(-1, 0),

					float2(-1, 1),

					float2(0, -1),

					float2(0, 1),

					float2(1, -1),

					float2(1, 0),

					float2(1, 1)

				};

				fixed4 sampledValue = fixed4(0,0,0,0);

				for (int j = 0; j < 8; j++) {

					sampledValue += GetPixelValue(i.uv + offsets[j] * _MainTex_TexelSize.xy);

				}

				sampledValue /= 8;

				return lerp(col, _EdgeColor, step(_Threshold, length(orValue - sampledValue)));

			}

			
			ENDCG
		}
    }
}