Shader - Custom Dilate Node for Shader Graph

Question

Can anyone assist me creating a custom node?
I'm new to shaders in general and I'm trying to achieve a Dilate effect combined with other visuals available through nodes already.
I got the desired effect I want minus the Dilate effect which I've got in a separate shader made by user poisoned_banana here: http://answers.unity.com/answers/1495613/view.html
I want to turn this Dilate effect into a node so I can apply it together with the effect I've created using Shader graph.
I tried this myself using the Custom Node API/Tutorial, but I can't get it to compile, I'm not quite sure which part of the shader I can put into the shader string and which variables to assign to which slots.

I've illustrated the problem I have in the following image.
alt text Outside red is my current effect which I want to combine with a custom Dilate effect node to get a sort of outline shader with effects.

I tried creating a custom node, but I'm not experienced enough with shaders to grasp what I'm doing. This doesn't work:

 using UnityEngine;
 using UnityEditor.ShaderGraph;
 using System.Reflection;
 
 [Title("Custom", "Dilate Unlit Node")]
 public class DilateUnlitNode : CodeFunctionNode
 {
     public DilateUnlitNode()
     {
         name = "Dilate Unlit Node";
     }
 
     protected override MethodInfo GetFunctionToConvert()
     {
         return GetType().GetMethod("DilateFunction", BindingFlags.Static | BindingFlags.NonPublic);
     }
 
 
     static string DilateFunction(
         [Slot(0, Binding.None)] Texture2D _MainTex,
         [Slot(1, Binding.None)] Vector1 _PixelOffset,
         [Slot(2, Binding.None)] out ColorRGBA finalColor)
     {
         return
                     @"
                         {
                             //min and max Vector
                             float2 _min = float2(0,0);
                             float2 _max = float2(1,1);
             
                             //get the color of 8 neighbour pixels
                             fixed4 U = tex2D(_MainTex,clamp(i.uv + float2(0,_PixelOffset),_min,_max));
                             fixed4 UR = tex2D(_MainTex,clamp(i.uv + float2(_PixelOffset,_PixelOffset),_min,_max));
                             fixed4 R = tex2D(_MainTex,clamp(i.uv + float2(_PixelOffset,0),_min,_max));
                             fixed4 DR = tex2D(_MainTex,clamp(i.uv + float2(_PixelOffset,-_PixelOffset),_min,_max));
                             fixed4 D = tex2D(_MainTex,clamp(i.uv + float2(0,-_PixelOffset),_min,_max));
                             fixed4 DL = tex2D(_MainTex,clamp(i.uv + float2(-_PixelOffset,-_PixelOffset),_min,_max));
                             fixed4 L = tex2D(_MainTex,clamp(i.uv + float2(-_PixelOffset,0),_min,_max));
                             fixed4 UL = tex2D(_MainTex,clamp(i.uv + float2(-_PixelOffset,_PixelOffset),_min,_max));
                             
                             //add all colors up to one final color
                             fixed4 finalColor = U + UR + R + DR + D + DL + L + UL;
             
                             //return final color
                             return finalColor;
                         } 
                     ";
     }
 }

Answer 1

I needed a dilate node too so I did the conversion. Use the below code in the body of a custom shader graph node of the type "string" name it "Dilate" and add the inputs: "tex" as Texture2D, "uv" as Vector2, "offset" as float, "state" as Sampler State. For outputs add "dilated" as a Vector4.

 float2 _min = float2(0,0);
 float2 _max = float2(1,1);
  
 float4 U = tex.Sample(state, clamp(uv + float2(0, offset),_min,_max));
 float4 UR = tex.Sample(state, clamp(uv + float2(offset, offset),_min,_max));
 float4  R = tex.Sample(state, clamp(uv + float2(offset, 0),_min,_max));
 float4 DR = tex.Sample(state, clamp(uv + float2(offset, -offset),_min,_max));
 float4 D = tex.Sample(state, clamp(uv + float2(0, -offset),_min,_max));
 float4  DL = tex.Sample(state, clamp(uv + float2(-offset, -offset),_min,_max));
 float4  L = tex.Sample(state, clamp(uv + float2(-offset, 0),_min,_max));
 float4 UL = tex.Sample(state, clamp(uv + float2(-offset, offset),_min,_max));
 
 dilated = U + UR + R + DR + D + DL + L + UL;

Confirmed to work in Shader Graph using URP in Unity 2020 LTS.

Shader - Custom Dilate Node for Shader Graph

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