def perspective(fovy, aspect, znear, zfar):
 assert (znear != zfar)
 h = (math.tan(((fovy / 360.0) * math.pi)) * znear)
 w = (h * aspect)
 return frustum((- w), w, (- h), h, znear, zfar)

def perspective ( fovy , aspect , znear , zfar ) : assert ( znear != zfar ) h = ( math . tan ( ( ( fovy / 360.0 ) * math . pi ) ) * znear ) w = ( h * aspect ) return frustum ( ( - w ) , w , ( - h ) , h , znear , zfar )
create perspective projection matrix parameters fovy : float the field of view along the y axis .