{ RCSid $Id: trans.cal,v 1.2 2003/10/08 17:10:53 greg Exp $ }
{
	These formulas give exact results from the infinite
	series solution for an uncoated pane of glass.

	Inputs:
		Tn	=	normal transmittance
		n	=	index of refraction

	Outputs:
		rn	=	single-layer normal reflectivity
		tn	=	transmissivity
		Rn	=	normal reflectance
}
Tn = 0.88;			{ normal transmittance }
n = 1.52;			{ index of refraction }

sq(x) : x*x;

rn = sq((1-n)/(1+n));

tn = (sqrt(sq(sq(1-rn))+4*sq(rn*Tn))-sq(1-rn)) / (2*sq(rn)*Tn);

Rn = rn + rn*sq((1-rn)*tn)/(1-sq(tn*rn));