Can we use shaders without materials?

Hi

I want to generate textures in a shader but not have have the shader associated to game objects / materials. Basically i just want to use it for image processing (in my case the Fourier transform).

Is this possible ? Or does only compute shaders provide this functionality?

 

Try "Custom Render Textures"

 

Thanks though i am a bit confused how a shader might apply to it. Since i won't have a mesh.. how does it use a vertex shader in that context?

Also if i want to process each pixel and no sub pixel calculations, how do you stop the fragment shader running between each pixel in the image ? I am basically trying to represent an image dimensions equal to my vertices so in between vertices would not make sense for my algorithm.

 

Do you read article from link?
<<how does it use a vertex shader in that context>>
Custom render texture generate Vertex data by itself.
<<Also if i want to process each pixel and no sub pixel calculations>>
Just use texture coords(maybe you need add half texel offset to it)

https://unitycoder.com/blog/2018/05/26/fire-effect-using-customrendertexture/
https://github.com/keijiro/RDSystem
https://github.com/hecomi/UnityWaterSurface

If you need write computation results not in current fragment texel position then traditional shader is no go, you should use compute shader instead.

 

Ah yeah i misread the vertex part my bad.

When you say just use texture coords.. won't that mean i will run the calculation more than once for a given pixel on a render texture ? Say the fragment shader runs for a sub pixel coordinate, i would need to calculate it down to the nearest pixel coordinate each time. So i would be processing the same pixel more than once right ? Is there no way to get around that? Or do i misunderstand what you meant?

 

If output render target size equals to input texture size(for Custom render texture it's always true) then texel size equals to fragment size and no subpixel reads.