fld [defaultFOV]
fld [number2]
fdiv
fldpi
fld [fov180]
fdiv
fmul
fld [arheight1]
fld [arheight2]
fdiv
fmul
fld [fov180]
fldpi
fdiv
fmul
fld [number2]
fmul
fstp [newFOV]