how to apply output of shader to the same shader?

Unity Engine
1

I made a shader that does holes on the screen.

What I want to do is to pass the output of the shader again to the same shader.

Currently my shader is applied on a quad that takes 2 textures as the input.
1 tex is background, the other is something to add to the background.

What is the best way of doing this?
Is the material shaded texture available again?
So I want to use the modified texture and modify it again and again and again.

Thanks

2

You can’t really retrieve “shader results” unless you’re doing an image effect where you render to a texture.

I think you only have 2 options:

  • Make your shader in such a way that the result is directly caused by passed parameters (from your script to the shader) so you can continue with said parameters in the next shader(s).
  • Make the shader in multiple passes.

What suits better depends on what you’re trying to achieve though.

3

You can store the result of the first pass in a RenderTexture, and use that as input the next time you run the shader.

Be careful though, writing to the texture you’re reading from can give some unexpected results, so draw into a different RenderTexture the second time.

4

Uhm yeah, what RC-1290 said. For some reason I thought RenderTextures only worked properly for Image Effects. Guess I was wrong :slight_smile:

5

Yup

I am looking into that.
The shader is already designed to take 2 textures as an input + some info parameters.
So I will render a texture to a render texture and use the output as input of the next operation to make sure all effects are done on the same texture.