How to render to texture with custom shader for current viewport?

Question

3D rendering

I need to get a texture which will then be used to render the post effect. As far as I understand, in order to get it, you need to render to a texture with a specific shader for the current viewporta-a. Then use this texture in the post effect shader.
In pure OpenGL, I would do this:

1. We clear the buffer.
   
2. Bind our custom shader.
   
3. We render everything.
   
4. Save to texture.
   
5. We clear the buffer.
   
6. Rendering with shaders that are attached to meshes.
   
7. We make a post effect with the texture that we got in step 5.
   
8. profit.
   

It's not clear to me how to stick steps 1-5 into Unity. Yes, there is Render to Texture, yes, you can render different layers, but there was no mention that this can be done with a custom shader.

Answer 1

You need Camera.RenderWithShader , OnRenderImage and manual .