--- ray/src/util/reinhartb.cal	2014/08/26 18:56:19	2.5
+++ ray/src/util/reinhartb.cal	2015/03/27 18:58:06	2.6
@@ -1,4 +1,4 @@
-{ RCSid $Id: reinhartb.cal,v 2.5 2014/08/26 18:56:19 greg Exp $ }
+{ RCSid $Id: reinhartb.cal,v 2.6 2015/03/27 18:58:06 greg Exp $ }
 {
 	Compute Reinhart high-density sky patch bin (rbin)
 
@@ -19,12 +19,14 @@ Atan2(y,x) : posangle(atan2(y,x));
 
 				{ Default to Tregenza sky }
 MF = 1;
+				{ Set to -1 for left-handed coordinate system }
+RHS = 1;
 				{ Default axis orientation (+Y == north) }
 rNx = 0; rNy = 0; rNz = -1;
 Ux = 0; Uy = 1; Uz = 0;
 				{ Compute oriented axis angles }
 inc_dz = -Dx*rNx-Dy*rNy-Dz*rNz;
-inc_rx = -Dx*(Uy*rNz-Uz*rNy) - Dy*(Uz*rNx-Ux*rNz) - Dz*(Ux*rNy-Uy*rNx);
+inc_rx = -RHS*(Dx*(Uy*rNz-Uz*rNy) + Dy*(Uz*rNx-Ux*rNz) + Dz*(Ux*rNy-Uy*rNx));
 inc_ry = Dx*Ux+Dy*Uy+Dz*Uz + inc_dz*(rNx*Ux+rNy*Uy+rNz*Uz);
 
 r_alt = Asin(inc_dz);