Resolved URP Sprite Gaussian Blur Customer SubShaderGraph

Hi all,

I decided to make a Gaussian Blur SubShaderGraph to be used into 2D pipline as I couldn't find anything that was working well.

I adopted the code from Daniel Lilett HERE but just updated it and cleaned it a bit to work in a custom function node.

Then that was converted into a SubShader so it can be easily used in any graph moving forward.

Custom Function Code Here:

Code (CSharp):

1. void GaussianBlur_float(UnityTexture2D Texture, float2 UV, float Blur, UnitySamplerState Sampler, out float3 Out_RGB, out float Out_Alpha)
2. {
3.     float4 col = float4(0.0, 0.0, 0.0, 0.0);
4.     float kernelSum = 0.0;
5.  
6.     int upper = ((Blur - 1) / 2);
7.     int lower = -upper;
8.  
9.     for (int x = lower; x <= upper; ++x)
10.     {
11.         for (int y = lower; y <= upper; ++y)
12.         {
13.             kernelSum ++;
14.  
15.             float2 offset = float2(_MainTex_TexelSize.x * x, _MainTex_TexelSize.y * y);
16.             col += Texture.Sample(Sampler, UV + offset);
17.         }
18.     }
19.  
20.     col /= kernelSum;
21.     Out_RGB = float3(col.r, col.g, col.b);
22.     Out_Alpha = col.a;
23. }

This is how it looks in graph:


And finally this is how the effect looks!


As the Depth Of Field post process doesn't work well in 2D and camera stacking is annoying this makes it much easier to get the blur effect you need.

 

This looks exactly like what I need! However, I'm getting an error in the shader graph:
"Shader error in 'Master': undeclared identifier '_MainTex_TexelSize' at Assets/Shaders/GaussianBlurSubShader.hlsl(15) (on d3d11)"

Any idea how I can fix this?

 

It is working, just open subgraph, add cging file by hand, and change precision to single. Then save, and you can use subgraph in your shader.
Thank you Graigy1337

 

Hi all!
This too looks like exactly what I need. I know next to nothing about HLSL though and I'm getting the same error. I'm trying to use this in an HDRP project in Unity 2021.3.15- could that be the problem? I too get "undeclared identifier '_MainTex_TexelSize' ". I've manually added the cging file and set the precision to single - inside the subshader for the node's precision. I don't get the error inside the subshader, only when I've added the subshader to another shader graph. I've tried adding...

Code (CSharp):

1. sampler2D _MainTex;
2. float4 _MainTex_TexelSize;

earlier in the script near the initialization of col and kernelSum. (I had read that maybe you need to declare them inside the function even if they might be declared somewhere else...? But that didn't solve it.) Any help or guidance would be appreciated!

 

Hi, you can also try accessing the "yourTexture_TexelSize" by Texture Size Node and expose the texel size property in the custom blur function.

The reason that MainTex is not defined may be because there's no texture called "_MainTex" in the shader properties panel.

 

Yea I'm getting this same error too.

-- Update --
Nevermind. To fix it do this in the new Shader Graph you created. Just add _MainTex in the "blackboard"
Like in the example from Graigy

 

For me unity shader don't see GaussianBlur Custom Function. How to fix it?

 

Fixed, ref for CustomFunction node was broken.

 

This look AMAZING, but when I apply the shader to a material and stick it on a sprite I'd like to blur it blurs everything except for the edges of the sprite. Example below:



I set up the shader graph exactly like in the example, am I just not able to blur sprites with half transparency?

 

It looks like you have a Tight Mesh on that sprite. Have you tried Full Rect on its Texture Import Settings? That should extend the edges.

 

That worked! So simple, thank you SO much for getting back to me!

 

I'm getting the "sampler2D object does not have methods at Assets/Art/Shaders/GaussianBlur.cginc(16) (on d3d11)" for the col += Texture.Sample(Sampler, UV + offset); part of the .cginc.

How did you guys prevent that from happening?

And there is also one more problem that keeps poping up, and that is

Shader error in 'Master': undeclared identifier 'GaussianBlur_half' at line 189 (on d3d11)

And when restarting unity, all of the errors above disappear and only this error is thrown
Shader error in 'AS_Character': redefinition of 'GaussianBlur_float' at Assets/Art/Shaders/GaussianBlur.cginc(1) (on d3d11)

 

amazing! but when i want to use something like Gradient noise to the blur input it gives an error, how should i change the shader to make it work with stuff like Gradient noise and alpha channels?

 

This sounds pretty specific so you should make a separate thread on it and post the code and error there.

 

Hi everyone! I did everything which Graigy suggested but I keep getting an error which says:
Shader error in 'Master': 'GaussianBlur_float': cannot implicitly convert from 'float3' to 'struct UnitySamplerState' at line 282 (on d3d11). Could someone please help me with this one?

 

Never mind, I fixed it. Thank you Graigy, this helped me a lot!

 

This is pretty nice but it's a Box Blur, not Gaussian blur. I noticed it also when you showed the GIF. In order to calculate a Gaussian blur you have to apply different weights for each sample, instead of aggregating the sample count.