How to get a quad tessellation where all the triangle diagonals slope the same way in Opengl?

Question

When you set inner and outer tessellation level to the same value you get:

But I wanna know how to get all the diagonals to slope the same way:

Answer 1

That is not something you have the power to control. Exactly how triangulation happens in tessellation is largely implementation-defined. Outside of basic consistency requirements (the same set of tessellation levels will triangulate in the same way), implementations could do anything. And different implementations can triangulate in a different way, even for the same tessellation levels.

Most uses of tessellation do not need this level of control over the way primitives are generated. If your use does need it, then you are going to have to implement tessellation yourself.