tessellation C++
WANING: I just wrote this, not fully tested, may contain bugs :)
1, this is C++ implementation of tessellation on CPU.
2, in source code, some classes/functions are not defined, but, it's easy to write your own.
3, and in tess.hlsl, it's a short code for removal of tessellation cracks.
4, and made this one, exactly like the one in DirectX.
5, made quad tessellation more rebust by supporting case like this one.
