I am looking for resources on what are the steps of manually implementing tessellation (I'm using Unity cg).

Today it seems that it is all the rage to hide most of the gpu code far away and use rather rigid simplifications such as unity's SURFace shaders. And it seems useless unless you're doing supeficial stuff.

A little background: I have procedurally generated meshes (using marching cubes) which have quality normals but no UVs and no Tangents. I have successfully written a custom vertex and fragment shader to do triplanar texture and bumpmap projection as well as some custom stuff (custom lighting, procedurally warping the texture for variation etc).

I am using the GPU Gems book as reference. Now I need to implement tessellation, but It seems I must calculate the tangents at runtime by swizzling normals (ctrl+f this in gems: <normal.z, normal.y, -normal.x>) before the tessellator gets them.

And I also need to keep my custom vert+frag setup (with my custom parameters/textures being passed between them) - so apparently I cannot use surface shaders.

Can anyone provide some guidence?