--- ray/src/common/bsdf_m.c	2011/02/24 20:14:26	3.8
+++ ray/src/common/bsdf_m.c	2011/04/20 14:44:05	3.11
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: bsdf_m.c,v 3.8 2011/02/24 20:14:26 greg Exp $";
+static const char RCSid[] = "$Id: bsdf_m.c,v 3.11 2011/04/20 14:44:05 greg Exp $";
 #endif
 /*
  *  bsdf_m.c
@@ -81,12 +81,12 @@ static int	nabases = 3;	/* current number of defined b
 static int
 fequal(double a, double b)
 {
-	if (b != .0)
+	if (b != 0)
 		a = a/b - 1.;
 	return (a <= 1e-6) & (a >= -1e-6);
 }
 
-/* returns the name of the given tag */
+/* Returns the name of the given tag */
 #ifdef ezxml_name
 #undef ezxml_name
 static char *
@@ -98,7 +98,7 @@ ezxml_name(ezxml_t xml)
 }
 #endif
 
-/* returns the given tag's character content or empty string if none */
+/* Returns the given tag's character content or empty string if none */
 #ifdef ezxml_txt
 #undef ezxml_txt
 static char *
@@ -159,14 +159,16 @@ SDnewMatrix(int ni, int no)
 
 /* get vector for this angle basis index (front exiting) */
 static int
-fo_getvec(FVECT v, int ndx, double randX, void *p)
+fo_getvec(FVECT v, double ndxr, void *p)
 {
-	ANGLE_BASIS  *ab = (ANGLE_BASIS *)p;
+	ANGLE_BASIS	*ab = (ANGLE_BASIS *)p;
+	int		ndx = (int)ndxr;
+	double		randX = ndxr - ndx;
 	double		rx[2];
 	int		li;
 	double		pol, azi, d;
 	
-	if ((ndx < 0) | (ndx >= ab->nangles))
+	if ((ndxr < 0) | (ndx >= ab->nangles))
 		return RC_FAIL;
 	for (li = 0; ndx >= ab->lat[li].nphis; li++)
 		ndx -= ab->lat[li].nphis;
@@ -185,13 +187,13 @@ fo_getvec(FVECT v, int ndx, double randX, void *p)
 static int
 fo_getndx(const FVECT v, void *p)
 {
-	ANGLE_BASIS  *ab = (ANGLE_BASIS *)p;
+	ANGLE_BASIS	*ab = (ANGLE_BASIS *)p;
 	int	li, ndx;
 	double	pol, azi, d;
 
 	if (v == NULL)
 		return -1;
-	if ((v[2] < .0) | (v[2] > 1.0))
+	if ((v[2] < 0) | (v[2] > 1.))
 		return -1;
 	pol = 180.0/M_PI*acos(v[2]);
 	azi = 180.0/M_PI*atan2(v[1], v[0]);
@@ -237,9 +239,9 @@ io_getohm(int ndx, void *p)
 
 /* get vector for this angle basis index (back incident) */
 static int
-bi_getvec(FVECT v, int ndx, double randX, void *p)
+bi_getvec(FVECT v, double ndxr, void *p)
 {
-	if (!fo_getvec(v, ndx, randX, p))
+	if (!fo_getvec(v, ndxr, p))
 		return RC_FAIL;
 
 	v[0] = -v[0];
@@ -264,9 +266,9 @@ bi_getndx(const FVECT v, void *p)
 
 /* get vector for this angle basis index (back exiting) */
 static int
-bo_getvec(FVECT v, int ndx, double randX, void *p)
+bo_getvec(FVECT v, double ndxr, void *p)
 {
-	if (!fo_getvec(v, ndx, randX, p))
+	if (!fo_getvec(v, ndxr, p))
 		return RC_FAIL;
 
 	v[2] = -v[2];
@@ -289,9 +291,9 @@ bo_getndx(const FVECT v, void *p)
 
 /* get vector for this angle basis index (front incident) */
 static int
-fi_getvec(FVECT v, int ndx, double randX, void *p)
+fi_getvec(FVECT v, double ndxr, void *p)
 {
-	if (!fo_getvec(v, ndx, randX, p))
+	if (!fo_getvec(v, ndxr, p))
 		return RC_FAIL;
 
 	v[0] = -v[0];
@@ -418,10 +420,11 @@ load_bsdf_data(SDData *sd, ezxml_t wdb, int rowinc)
 	sdata = ezxml_txt(ezxml_child(wdb, "WavelengthDataDirection"));
 	/*
 	 * Remember that front and back are reversed from WINDOW 6 orientations
+	 * Favor their "Front" (incoming light) since that's more often valid
 	 */
-	if ((tfront = !strcasecmp(sdata, "Transmission Back")) ||
-			(sd->tf == NULL &&
-				!strcasecmp(sdata, "Transmission Front"))) {
+	tfront = !strcasecmp(sdata, "Transmission Back");
+	if (!strcasecmp(sdata, "Transmission Front") ||
+			tfront & (sd->tf == NULL)) {
 		if (sd->tf != NULL)
 			SDfreeSpectralDF(sd->tf);
 		if ((sd->tf = SDnewSpectralDF(1)) == NULL)
@@ -504,7 +507,7 @@ load_bsdf_data(SDData *sd, ezxml_t wdb, int rowinc)
 	df->comp[0].dist = dp;
 	df->comp[0].func = &SDhandleMtx;
 					/* read BSDF data */
-	sdata  = ezxml_txt(ezxml_child(wdb,"ScatteringData"));
+	sdata = ezxml_txt(ezxml_child(wdb,"ScatteringData"));
 	if (!sdata || !*sdata) {
 		sprintf(SDerrorDetail, "Missing BSDF ScatteringData in '%s'",
 				sd->name);
@@ -648,16 +651,23 @@ SDgetMtxBSDF(float coef[SDmaxCh], const FVECT outVec,
 
 /* Query solid angle for vector */
 static SDError
-SDqueryMtxProjSA(double *psa, const FVECT vec, int qflags, const void *dist)
+SDqueryMtxProjSA(double *psa, const FVECT v1, const RREAL *v2,
+					int qflags, const void *dist)
 {
 	const SDMat	*dp = (const SDMat *)dist;
 	double		inc_psa, out_psa;
 					/* check arguments */
-	if ((psa == NULL) | (vec == NULL) | (dp == NULL))
+	if ((psa == NULL) | (v1 == NULL) | (dp == NULL))
 		return SDEargument;
+	if (v2 == NULL)
+		v2 = v1;
 					/* get projected solid angles */
-	inc_psa = mBSDF_incohm(dp, mBSDF_incndx(dp, vec));
-	out_psa = mBSDF_outohm(dp, mBSDF_outndx(dp, vec));
+	out_psa = mBSDF_outohm(dp, mBSDF_outndx(dp, v1));
+	inc_psa = mBSDF_incohm(dp, mBSDF_incndx(dp, v2));
+	if ((out_psa <= 0) & (inc_psa <= 0)) {
+		inc_psa = mBSDF_outohm(dp, mBSDF_outndx(dp, v2));
+		out_psa = mBSDF_incohm(dp, mBSDF_incndx(dp, v1));
+	}
 
 	switch (qflags) {		/* record based on flag settings */
 	case SDqueryVal:
@@ -676,14 +686,14 @@ SDqueryMtxProjSA(double *psa, const FVECT vec, int qfl
 			psa[1] = out_psa;
 		/* fall through */
 	case SDqueryMin:
-		if ((inc_psa > .0) & (inc_psa < psa[0]))
+		if ((inc_psa > 0) & (inc_psa < psa[0]))
 			psa[0] = inc_psa;
-		if ((out_psa > .0) & (out_psa < psa[0]))
+		if ((out_psa > 0) & (out_psa < psa[0]))
 			psa[0] = out_psa;
 		break;
 	}
 					/* make sure it's legal */
-	return (psa[0] <= .0) ? SDEinternal : SDEnone;
+	return (psa[0] <= 0) ? SDEinternal : SDEnone;
 }
 
 /* Compute new cumulative distribution from BSDF */
@@ -795,7 +805,7 @@ SDsampMtxCDist(FVECT outVec, double randX, const SDCDs
 	randX = (randX*maxval - mcd->carr[ilower]) /
 			(double)(mcd->carr[iupper] - mcd->carr[ilower]);
 					/* convert index to vector */
-	if ((*mcd->ob_vec)(outVec, i, randX, mcd->ob_priv))
+	if ((*mcd->ob_vec)(outVec, i+randX, mcd->ob_priv))
 		return SDEnone;
 	strcpy(SDerrorDetail, "BSDF sampling fault");
 	return SDEinternal;