Implementation of perspective()

I’m working on a 3D Lua graphics library for Mac (a modification of Love2D, to be specific), and I’m trying to create a perspective() function which mirrors the behavior of perspective() in Codea. In the documentation, however, for the default value of zfar, it just says “calculated using Height.” Could I have a more specific definition to use in my library, as in Codea the default seems to work quite well. Thanks in advance!

Here is how we compute it:

zFar = ( ( height/2.0f ) / tan( pi * 60.0 / 360.0 ) ) * 10