Hidden operations of the Direct3D pipeline

Question

I'm curious- what operations are there in Direct3D that aren't controlled directly through shader, or directly to do with shader manipulation- i.e., that occur behind the scenes.

So far, I've got just pixel interpolation.

Answer 1

Off the top of my head: There is triangle setup, triangle clipping, backface removal, rasterization, raster operations (blending), z testing, tessellation, texture filtering, shadow map texture depth testing, stencil ops, pixel/buffer format conversion.

Answer 2

Tessellation. It is a separate fixed function system that doesn't have a 1:1 with OpenGL and will result in different tessellation unlike shaders which can be ported fairly easily. http://msdn.microsoft.com/en-us/library/bb206188%28v=vs.85%29.aspx