h = 2. * cam.getDistance() * Math.tan(cam.getFovY() / 2.);
l = h * (((double) width) / ((double) height));
u = dir.crossProduct(cam.getUp()).normal().product(l / (double) width);
v = dir.crossProduct(u).normal().product(h / (double) height);
ori = pos.add(dir.product(cam.getDistance()))
.add(u.product(-(double) width / 2.))
.add(v.product(-(double) height / 2.));
}
@Override