How to make an Infinite plane?

I want to make an infinite floor which give the user the illusion of moving in an infinite space.
I think I should draw the part of the infinite floor that lies underneath the camera, wherever the camera happens to be.

However I don’t know how to code it…
Can you all give me example or tutorial for me to reference?

Thanks you very much.

[This message has been edited by takumi (edited 08-24-2002).]