// Upgrade NOTE: replaced 'mul(UNITY_MATRIX_MVP,*)' with 'UnityObjectToClipPos(*)'

Shader "Custom/Post Outline"
{
	Properties
	{
		 _Color("Main Color", Color) = (0.5,0.5,0.5,1)
		_MainTex("Main Texture",2D) = "black"{}
		_SceneTex("Scene Texture",2D) = "black"{}
	}
	
	SubShader
	{
		// Fog { Mode Off }
		 ZWrite off
			 Cull Off
			Lighting Off

		Pass
		{
			CGPROGRAM

			sampler2D _MainTex;
	float4 _Color;

			//<SamplerName>_TexelSize is a float2 that says how much screen space a texel occupies.
			float2 _MainTex_TexelSize;

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

			struct v2f
			{
				float4 pos : SV_POSITION;
				float2 uvs : TEXCOORD0;
			};

			v2f vert(appdata_base v)
			{
				v2f o;

				//Despite the fact that we are only drawing a quad to the screen, Unity requires us to multiply vertices by our MVP matrix, presumably to keep things working when inexperienced people try copying code from other shaders.
				o.pos = UnityObjectToClipPos(v.vertex);

				//Also, we need to fix the UVs to match our screen space coordinates. There is a Unity define for this that should normally be used.
				o.uvs = o.pos.xy / 2 + 0.5;

				return o;
			}


			half frag(v2f i) : COLOR
			{
				//arbitrary number of iterations for now
				int NumberOfIterations = 4;

				//split texel size into smaller words
				float TX_x = _MainTex_TexelSize.x;

				//and a final intensity that increments based on surrounding intensities.
				float ColorIntensityInRadius;

				//for every iteration we need to do horizontally
				for (int k = 0; k < NumberOfIterations; k += 1)
				{
					//increase our output color by the pixels in the area
					ColorIntensityInRadius += tex2D(
						_MainTex,
						i.uvs.xy + float2((k - NumberOfIterations / 2)*TX_x, 0)).r / NumberOfIterations;
				}
				//output some intensity of teal
			//	ColorIntensityInRadius = 0;

				return ColorIntensityInRadius;
			}
		ENDCG

		}
		//end pass    

		GrabPass{}

		Pass
		{
				ZWrite off

			CGPROGRAM

			sampler2D _MainTex;
			sampler2D _SceneTex;

			//we need to declare a sampler2D by the name of "_GrabTexture" that Unity can write to during GrabPass{}
			sampler2D _GrabTexture;

			//<SamplerName>_TexelSize is a float2 that says how much screen space a texel occupies.
			float2 _GrabTexture_TexelSize;

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

			struct v2f
			{
				float4 pos : SV_POSITION;
				float2 uvs : TEXCOORD0;
			};

			v2f vert(appdata_base v)
			{
				v2f o;

				//Despite the fact that we are only drawing a quad to the screen, Unity requires us to multiply vertices by our MVP matrix, presumably to keep things working when inexperienced people try copying code from other shaders.
				o.pos = UnityObjectToClipPos(v.vertex);

				//Also, we need to fix the UVs to match our screen space coordinates. There is a Unity define for this that should normally be used.
				o.uvs = o.pos.xy / 2 + 0.5; // smooth rough line

				return o;
			}


			half4 frag(v2f i) : COLOR
			{
				//arbitrary number of iterations for now
				int NumberOfIterations = 20;

				//split texel size into smaller words
				float TX_y = _GrabTexture_TexelSize.y; //here we can change outline width

				//and a final intensity that increments based on surrounding intensities.
				half ColorIntensityInRadius = 0;

				//if something already exists underneath the fragment (in the original texture), discard the fragment.
				if (tex2D(_MainTex,i.uvs.xy).r > 0)
				{
					return tex2D(_SceneTex,float2(i.uvs.x,1 - i.uvs.y));
				}

				//for every iteration we need to do vertically
				for (int j = 0; j < NumberOfIterations; j += 1)
				{
					//increase our output color by the pixels in the area
					ColorIntensityInRadius += tex2D(
													_GrabTexture,
													float2(i.uvs.x,1 - i.uvs.y) + float2
																					(
																						0,
																						(j - NumberOfIterations / 2)*TX_y 
																					)
												//	).r / (NumberOfIterations);
													).r / (1);
				}

				//this is alpha blending, but we can't use HW blending unless we make a third pass, so this is probably cheaper.
			//	half4 outcolor = ColorIntensityInRadius * half4(0,1,1,1) * 2 + (1 - ColorIntensityInRadius)*tex2D(_SceneTex,float2(i.uvs.x,1 - i.uvs.y));
				half4 outcolor = half4(0, 0, 0, 0)  + (1 - ColorIntensityInRadius)  *tex2D(_SceneTex, float2(i.uvs.x, 1 - i.uvs.y));

			//	outcolor = (outcolor[0], outcolor[1], outcolor[2], 0.5f);
				return outcolor;
			}
		ENDCG
		}
		//end pass    
	}
	//end subshader
}
//end shader