I'm a game dev student and last semester we had a '3D-programming' course, in which we did some basic stuff such as rendering a textured quad spinning around in the "scene". We used quite basic vertex-, geometry-, and fragment-shaders to do this.

Sorry if the question is poorly formulated, hope it makes some sense. ^^'

An example would be great, HLSL/D3D or GLSL/OpenGL doesnt matter, I've fiddled with both.

The other approach is the uber shader. This is a very broad term, and you won't find a lot about it on the internet either. Usually, uber shaders are massive shader programs meant to deal with a variety of rendering situations (however, post-processing is usually not one of them). They either use compile time (#define, #if) or runtime (if (...)) switches to handle different scenarios. Sometimes even water and other reflecting or refracting surfaces are included in the mix. If you want, you can literally include every shader program in a single file, but it's not advised.