{
	Coordinate mapping for globe onto unit sphere
	assuming uniform projection of latitude and longitude

	A1 = image height/width
}

globe_u = if(A1-1, 1, 1/A1) * (.5 + Atan2(Py, Px)/(2*PI)) ;

globe_v = if(A1-1, A1, 1) * (1 - Acos(Pz)/PI) ;
