Hardware tessellation shaders only are available on tessellation-capable hardware. Right. But what makes this hardware capable of tessellation?
I mean, GeForce 8xxx or 2xx GPUs have a general-purpose GPU. For instance, one can find CUDA tessellation libraries on the net.
What is this magical thing done by newer hardware that effectively enables hardware tessellation? What is this piece of silicon (maybe the tessellation unit or something), what does it do so much better than software, could somebody explain me maybe how poorly a CUDA piece of code would perform to do the same thing?
Sorry if this question sounds stupid but so far I can't find the answer.