Post processing shader screen overlay issues

Unity Engine
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1

I am trying to make a post processing shader that creates a post processing effect, right now my shader just makes my camera effect display the current screen but slightly brighter when the post processing shader is enabled. What I am trying to do is duplicate the screen, blur that image, then apply as overlay to make the camera have a dreamy like effect, where the edges of objects are slightly glowing. For a good reference if you duplicate a image in photoshop, then apply a slight guassian blur to the top image and use overlay. Below is the script I made but the blur part of the effect is not showing for some reason.

Shader "Hidden/Custom/ScreenOverlayNew"
{
    HLSLINCLUDE

#include "Packages/com.unity.postprocessing/PostProcessing/Shaders/StdLib.hlsl"

    TEXTURE2D_SAMPLER2D(_MainTex, sampler_MainTex);
    float _Opacity;
    float _BlurSize = 0.5f;
    float4 texelSize = 0.5f;

    float4 Frag(VaryingsDefault i) : SV_Target{
        float4 base = SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, i.texcoord);
 
        // Add the blur by sampling the texture in a kernel
        base += SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, i.texcoord + texelSize.xy * float2(-_BlurSize, -_BlurSize)) * 0.05;
        base += SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, i.texcoord + texelSize.xy * float2(-_BlurSize, 0)) * 0.09;
        base += SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, i.texcoord + texelSize.xy * float2(-_BlurSize, _BlurSize)) * 0.05;
        base += SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, i.texcoord + texelSize.xy * float2(0, -_BlurSize)) * 0.09;
        base += SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, i.texcoord + texelSize.xy * float2(0, 0)) * 0.16;
        base += SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, i.texcoord + texelSize.xy * float2(0, _BlurSize)) * 0.09;
        base += SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, i.texcoord + texelSize.xy * float2(_BlurSize, -_BlurSize)) * 0.05;
        base += SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, i.texcoord + texelSize.xy * float2(_BlurSize, 0)) * 0.09;
        base += SAMPLE_TEXTURE2D(_MainTex, sampler_MainTex, i.texcoord + texelSize.xy * float2(_BlurSize, _BlurSize)) * 0.05;
        base /= 1.6;

        float4 calculateBase = (1 - (1 - base)*(1 - base));
        return lerp(calculateBase, base, 0.75f);
    }

        ENDHLSL

        SubShader {
        Cull Off ZWrite Off ZTest Always

        Pass
        {
            HLSLPROGRAM
            #pragma vertex VertDefault
            #pragma fragment Frag
            ENDHLSL
        }
    }
}
2

Can anyone please help? I have not been able to resolve this issue

3

The “texel size” needs to be in normalize UV space. 0.5 is half the entire texture. If you’re rendering at 1920x1080 then the xy values need to be 1.0/1920.0 and 1.0/1080.0 respectively. Or you can use:

float4 _MainTex_TexelSize;

And Unity will fill in those values automatically.

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