plot 3d function or 2d contour in a quadtree mesh type

Hello guys, I'm trying to plot any kind of function of two variables, or 2d contour of the same function, on a mesh type like the one in the picture:

I manged to do something like this, just to start, but I've plotted this surf (view(0.90)) separating it in 3 different surf, I'm looking for a way to do it just with one single surf or something "easier" to manage.