Shader object

I’d like to ask for object that would let you use shaders on specific area (rectangle). Why area? So it’d be easy to combine several shaders that affect different parts of the screen without combining them into one huge hard to debug shader (example: “reflection” shader for things like water and “wavy” shader for areas where fire happens).

On first iteration it’d probably just accept GLSL code, later we could do something like node-based shader editor.