--- ray/src/common/bsdf_t.c	2012/09/02 15:33:15	3.24
+++ ray/src/common/bsdf_t.c	2013/07/04 15:14:45	3.30
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: bsdf_t.c,v 3.24 2012/09/02 15:33:15 greg Exp $";
+static const char RCSid[] = "$Id: bsdf_t.c,v 3.30 2013/07/04 15:14:45 greg Exp $";
 #endif
 /*
  *  bsdf_t.c
@@ -499,9 +499,16 @@ build_scaffold(float val, const double *cmin, double c
 {
 	SDdistScaffold	*sp = (SDdistScaffold *)cptr;
 	int		wid = csiz*(double)iwmax + .5;
+	double		revcmin[2];
 	bitmask_t	bmin[2], bmax[2];
 
-	cmin += sp->nic * !sp->rev;	/* skip to output coords */
+	if (sp->rev) {			/* need to reverse sense? */
+		revcmin[0] = 1. - cmin[0] - csiz;
+		revcmin[1] = 1. - cmin[1] - csiz;
+		cmin = revcmin;
+	} else {
+		cmin += sp->nic;	/* else skip to output coords */
+	}
 	if (wid < sp->wmin)		/* new minimum width? */
 		sp->wmin = wid;
 	if (wid > sp->wmax)		/* new maximum? */
@@ -596,7 +603,7 @@ make_cdist(const SDTre *sdt, const double *invec, int 
 					/* record input range */
 	scale = myScaffold.wmin / (double)iwmax;
 	for (i = myScaffold.nic; i--; ) {
-		cd->clim[i][0] = floor(pos[i]/scale) * scale;
+		cd->clim[i][0] = floor(pos[i+2*rev]/scale) * scale;
 		cd->clim[i][1] = cd->clim[i][0] + scale;
 	}
 	if (cd->isodist) {		/* avoid issue in SDqueryTreProjSA() */
@@ -667,7 +674,10 @@ SDgetTreCDist(const FVECT inVec, SDComponent *sdc)
 			return &SDemptyCD;
 		inCoord[0] = .5 - .5*sqrt(inVec[0]*inVec[0] + inVec[1]*inVec[1]);
 	} else if (sdt->st->ndim == 4) {
-		SDdisk2square(inCoord, -inVec[0], -inVec[1]);
+		if (mode != sdt->sidef)	/* use reciprocity? */
+			SDdisk2square(inCoord, inVec[0], inVec[1]);
+		else
+			SDdisk2square(inCoord, -inVec[0], -inVec[1]);
 	} else
 		return NULL;		/* should be internal error */
 					/* quantize to avoid f.p. errors */
@@ -718,10 +728,12 @@ SDqueryTreProjSA(double *psa, const FVECT v1, const RR
 	} else {
 		const SDTreCDst	*cd = (const SDTreCDst *)SDgetTreCDist(v1, sdc);
 		if (cd == NULL)
-			return SDEmemory;
-		myPSA[0] = M_PI * (cd->clim[0][1] - cd->clim[0][0]) *
-				(cd->clim[1][1] - cd->clim[1][0]);
-		myPSA[1] = cd->max_psa;
+			myPSA[0] = myPSA[1] = 0;
+		else {
+			myPSA[0] = M_PI * (cd->clim[0][1] - cd->clim[0][0]) *
+					(cd->clim[1][1] - cd->clim[1][0]);
+			myPSA[1] = cd->max_psa;
+		}
 	}
 	switch (qflags) {		/* record based on flag settings */
 	case SDqueryVal:
@@ -736,7 +748,7 @@ SDqueryTreProjSA(double *psa, const FVECT v1, const RR
 			psa[1] = myPSA[1];
 		/* fall through */
 	case SDqueryMin:
-		if (myPSA[0] < psa[0])
+		if ((myPSA[0] > 0) & (myPSA[0] < psa[0]))
 			psa[0] = myPSA[0];
 		break;
 	}
@@ -947,25 +959,25 @@ load_bsdf_data(SDData *sd, ezxml_t wdb, int ndim)
 	 * Remember that front and back are reversed from WINDOW 6 orientations
 	 */
 	if (!strcasecmp(sdata, "Transmission Front")) {
-		if (sd->tf != NULL)
-			SDfreeSpectralDF(sd->tf);
-		if ((sd->tf = SDnewSpectralDF(1)) == NULL)
-			return SDEmemory;
-		df = sd->tf;
-	} else if (!strcasecmp(sdata, "Transmission Back")) {
 		if (sd->tb != NULL)
 			SDfreeSpectralDF(sd->tb);
 		if ((sd->tb = SDnewSpectralDF(1)) == NULL)
 			return SDEmemory;
 		df = sd->tb;
+	} else if (!strcasecmp(sdata, "Transmission Back")) {
+		if (sd->tf != NULL)
+			SDfreeSpectralDF(sd->tf);
+		if ((sd->tf = SDnewSpectralDF(1)) == NULL)
+			return SDEmemory;
+		df = sd->tf;
 	} else if (!strcasecmp(sdata, "Reflection Front")) {
-		if (sd->rb != NULL)	/* note back-front reversal */
+		if (sd->rb != NULL)
 			SDfreeSpectralDF(sd->rb);
 		if ((sd->rb = SDnewSpectralDF(1)) == NULL)
 			return SDEmemory;
 		df = sd->rb;
 	} else if (!strcasecmp(sdata, "Reflection Back")) {
-		if (sd->rf != NULL)	/* note front-back reversal */
+		if (sd->rf != NULL)
 			SDfreeSpectralDF(sd->rf);
 		if ((sd->rf = SDnewSpectralDF(1)) == NULL)
 			return SDEmemory;
@@ -1153,7 +1165,10 @@ SDloadTre(SDData *sd, ezxml_t wtl)
 					/* separate diffuse components */
 	extract_diffuse(&sd->rLambFront, sd->rf);
 	extract_diffuse(&sd->rLambBack, sd->rb);
-	extract_diffuse(&sd->tLamb, (sd->tf != NULL) ? sd->tf : sd->tb);
+	if (sd->tf != NULL)
+		extract_diffuse(&sd->tLamb, sd->tf);
+	if (sd->tb != NULL)
+		extract_diffuse(&sd->tLamb, sd->tb);
 					/* return success */
 	return SDEnone;
 }