private void drawLine(Graphics g, Vector p, Vector q) {
// FIXME: maybe eliminate class instantiations
// from this method for performance reasons:
// use static point arrays for transformations
Vector u = rotation.apply(p.sub(origin));
Vector v = rotation.apply(q.sub(origin));
Point2D.Double from = new Point2D.Double(u.getX(), u.getZ());
Point2D.Double to = new Point2D.Double(v.getX(), v.getZ());
Point ifrom = new Point();
Point ito = new Point();
transform.transform(from, ifrom);
transform.transform(to, ito);
// g.drawLine(xInt(u.getX()),yInt(u.getZ()),
// xInt(v.getX()),yInt(v.getZ()));
g.drawLine(ifrom.x, ifrom.y, ito.x, ito.y);
}
