--- ray/src/common/bsdf.c	2012/10/13 20:15:43	2.43
+++ ray/src/common/bsdf.c	2021/04/28 00:59:10	2.60
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: bsdf.c,v 2.43 2012/10/13 20:15:43 greg Exp $";
+static const char RCSid[] = "$Id: bsdf.c,v 2.60 2021/04/28 00:59:10 greg Exp $";
 #endif
 /*
  *  bsdf.c
@@ -35,6 +35,9 @@ const char		*SDerrorEnglish[] = {
 				"Unknown error"
 			};
 
+/* Pointer to error list in preferred language */
+const char		**SDerrorList = SDerrorEnglish;
+
 /* Additional information on last error (ASCII English) */
 char			SDerrorDetail[256];
 
@@ -44,12 +47,15 @@ const SDCDst		SDemptyCD;
 /* Cache of loaded BSDFs */
 struct SDCache_s	*SDcacheList = NULL;
 
-/* Retain BSDFs in cache list */
+/* Retain BSDFs in cache list? */
 int			SDretainSet = SDretainNone;
 
-/* Report any error to the indicated stream (in English) */
+/* Maximum cache size for any given BSDF? */
+unsigned long		SDmaxCache = 0;		/* 0 == unlimited */
+
+/* Report any error to the indicated stream */
 SDError
-SDreportEnglish(SDError ec, FILE *fp)
+SDreportError(SDError ec, FILE *fp)
 {
 	if (!ec)
 		return SDEnone;
@@ -59,7 +65,7 @@ SDreportEnglish(SDError ec, FILE *fp)
 	}
 	if (fp == NULL)
 		return ec;
-	fputs(SDerrorEnglish[ec], fp);
+	fputs(SDerrorList[ec], fp);
 	if (SDerrorDetail[0]) {
 		fputs(": ", fp);
 		fputs(SDerrorDetail, fp);
@@ -196,7 +202,7 @@ SDloadFile(SDData *sd, const char *fname)
 	}
 	wtl = ezxml_child(ezxml_child(fl, "Optical"), "Layer");
 	if (wtl == NULL) {
-		sprintf(SDerrorDetail, "BSDF \"%s\": no optical layers'",
+		sprintf(SDerrorDetail, "BSDF \"%s\": no optical layers",
 				sd->name);
 		ezxml_free(fl);
 		return SDEformat;
@@ -324,6 +330,8 @@ SDclipName(char *res, const char *fname)
 	for (cp = fname; *cp; cp++)
 		if (*cp == '.')
 			dot = cp;
+		else if (*cp == '/')
+			dot = NULL;
 	if ((dot == NULL) | (dot < fname+2))
 		dot = cp;
 	if (dot - fname >= SDnameLn)
@@ -375,8 +383,10 @@ SDfreeBSDF(SDData *sd)
 	sd->rLambFront.spec.flags = 0;
 	sd->rLambBack.cieY = .0;
 	sd->rLambBack.spec.flags = 0;
-	sd->tLamb.cieY = .0;
-	sd->tLamb.spec.flags = 0;
+	sd->tLambFront.cieY = .0;
+	sd->tLambFront.spec.flags = 0;
+	sd->tLambBack.cieY = .0;
+	sd->tLambBack.spec.flags = 0;
 }
 
 /* Find writeable BSDF by name, or allocate new cache entry if absent */
@@ -419,15 +429,17 @@ SDcacheFile(const char *fname)
 	if (fname == NULL || !*fname)
 		return NULL;
 	SDerrorDetail[0] = '\0';
+	/* PLACE MUTEX LOCK HERE FOR THREAD-SAFE */
 	if ((sd = SDgetCache(fname)) == NULL) {
-		SDreportEnglish(SDEmemory, stderr);
+		SDreportError(SDEmemory, stderr);
 		return NULL;
 	}
 	if (!SDisLoaded(sd) && (ec = SDloadFile(sd, fname))) {
-		SDreportEnglish(ec, stderr);
+		SDreportError(ec, stderr);
 		SDfreeCache(sd);
-		return NULL;
+		sd = NULL;
 	}
+	/* END MUTEX LOCK */
 	return sd;
 }
 
@@ -485,16 +497,15 @@ SDsampComponent(SDValue *sv, FVECT ioVec, double randX
 		return SDEargument;
 					/* get cumulative distribution */
 	VCOPY(inVec, ioVec);
+	sv->cieY = 0;
 	cd = (*sdc->func->getCDist)(inVec, sdc);
-	if (cd == NULL)
-		return SDEmemory;
-	if (cd->cTotal <= 1e-6) {	/* anything to sample? */
+	if (cd != NULL)
+		sv->cieY = cd->cTotal;
+	if (sv->cieY <= 1e-6) {		/* nothing to sample? */
 		sv->spec = c_dfcolor;
-		sv->cieY = .0;
-		memset(ioVec, 0, 3*sizeof(double));
+		memset(ioVec, 0, sizeof(FVECT));
 		return SDEnone;
 	}
-	sv->cieY = cd->cTotal;
 					/* compute sample direction */
 	ec = (*sdc->func->sampCDist)(ioVec, randX, cd);
 	if (ec)
@@ -511,8 +522,7 @@ SDsampComponent(SDValue *sv, FVECT ioVec, double randX
 		c_cmix(&sv->spec, d, &sv->spec, coef[n], &sdc->cspec[n]);
 		d += coef[n];
 	}
-					/* make sure everything is set */
-	c_ccvt(&sv->spec, C_CSXY+C_CSSPEC);
+	c_ccvt(&sv->spec, C_CSXY);	/* make sure (x,y) is set */
 	return SDEnone;
 }
 
@@ -556,8 +566,7 @@ SDdiffuseSamp(FVECT outVec, int outFront, double randX
 	SDmultiSamp(outVec, 2, randX);
 	SDsquare2disk(outVec, outVec[0], outVec[1]);
 	outVec[2] = 1. - outVec[0]*outVec[0] - outVec[1]*outVec[1];
-	if (outVec[2] > 0)		/* a bit of paranoia */
-		outVec[2] = sqrt(outVec[2]);
+	outVec[2] = sqrt(outVec[2]*(outVec[2]>0));
 	if (!outFront)			/* going out back? */
 		outVec[2] = -outVec[2];
 }
@@ -594,11 +603,12 @@ SDsizeBSDF(double *projSA, const FVECT v1, const RREAL
 		rdf = sd->rb;
 		tdf = (sd->tb != NULL) ? sd->tb : sd->tf;
 	}
-	if (v2 != NULL)			/* bidirectional? */
+	if (v2 != NULL) {		/* bidirectional? */
 		if (v1[2] > 0 ^ v2[2] > 0)
 			rdf = NULL;
 		else
 			tdf = NULL;
+	}
 	ec = SDEdata;			/* run through components */
 	for (i = (rdf==NULL) ? 0 : rdf->ncomp; i--; ) {
 		ec = (*rdf->comp[i].func->queryProjSA)(projSA, v1, v2,
@@ -616,7 +626,8 @@ SDsizeBSDF(double *projSA, const FVECT v1, const RREAL
 		projSA[0] = M_PI;
 		if (qflags == SDqueryMin+SDqueryMax)
 			projSA[1] = M_PI;
-	}
+	} else if (qflags == SDqueryMin+SDqueryMax && projSA[0] > projSA[1])
+		projSA[0] = projSA[1];
 	return SDEnone;
 }
 
@@ -642,10 +653,10 @@ SDevalBSDF(SDValue *sv, const FVECT outVec, const FVEC
 		*sv = sd->rLambBack;
 		sdf = sd->rb;
 	} else if (inFront) {
-		*sv = sd->tLamb;
+		*sv = sd->tLambFront;
 		sdf = (sd->tf != NULL) ? sd->tf : sd->tb;
-	} else /* inBack */ {
-		*sv = sd->tLamb;
+	} else /* outFront & !inFront */ {
+		*sv = sd->tLambBack;
 		sdf = (sd->tb != NULL) ? sd->tb : sd->tf;
 	}
 	sv->cieY *= 1./M_PI;
@@ -660,8 +671,7 @@ SDevalBSDF(SDValue *sv, const FVECT outVec, const FVEC
 			sv->cieY += coef[nch];
 		}
 	}
-					/* make sure everything is set */
-	c_ccvt(&sv->spec, C_CSXY+C_CSSPEC);
+	c_ccvt(&sv->spec, C_CSXY);	/* make sure (x,y) is set */
 	return SDEnone;
 }
 
@@ -689,7 +699,8 @@ SDdirectHemi(const FVECT inVec, int sflags, const SDDa
 	if ((sflags & SDsampDf+SDsampR) != SDsampDf+SDsampR)
 		hsum = .0;
 	if ((sflags & SDsampDf+SDsampT) == SDsampDf+SDsampT)
-		hsum += sd->tLamb.cieY;
+		hsum += (inVec[2] > 0) ?
+				sd->tLambFront.cieY : sd->tLambBack.cieY;
 					/* gather non-diffuse components */
 	i = (((sflags & SDsampSp+SDsampR) == SDsampSp+SDsampR) &
 			(rdf != NULL)) ? rdf->ncomp : 0;
@@ -742,7 +753,7 @@ SDsampBSDF(SDValue *sv, FVECT ioVec, double randX, int
 		sv->cieY = .0;
 	rdiff = sv->cieY;
 	if ((sflags & SDsampDf+SDsampT) == SDsampDf+SDsampT)
-		sv->cieY += sd->tLamb.cieY;
+		sv->cieY += inFront ? sd->tLambFront.cieY : sd->tLambBack.cieY;
 					/* gather non-diffuse components */
 	i = nr = (((sflags & SDsampSp+SDsampR) == SDsampSp+SDsampR) &
 			(rdf != NULL)) ? rdf->ncomp : 0;
@@ -753,23 +764,19 @@ SDsampBSDF(SDValue *sv, FVECT ioVec, double randX, int
 		return SDEmemory;
 	while (j-- > 0) {		/* non-diffuse transmission */
 		cdarr[i+j] = (*tdf->comp[j].func->getCDist)(inVec, &tdf->comp[j]);
-		if (cdarr[i+j] == NULL) {
-			free(cdarr);
-			return SDEmemory;
-		}
+		if (cdarr[i+j] == NULL)
+			cdarr[i+j] = &SDemptyCD;
 		sv->cieY += cdarr[i+j]->cTotal;
 	}
 	while (i-- > 0) {		/* non-diffuse reflection */
 		cdarr[i] = (*rdf->comp[i].func->getCDist)(inVec, &rdf->comp[i]);
-		if (cdarr[i] == NULL) {
-			free(cdarr);
-			return SDEmemory;
-		}
+		if (cdarr[i] == NULL)
+			cdarr[i] = &SDemptyCD;
 		sv->cieY += cdarr[i]->cTotal;
 	}
 	if (sv->cieY <= 1e-6) {		/* anything to sample? */
 		sv->cieY = .0;
-		memset(ioVec, 0, 3*sizeof(double));
+		memset(ioVec, 0, sizeof(FVECT));
 		return SDEnone;
 	}
 					/* scale random variable */
@@ -782,15 +789,16 @@ SDsampBSDF(SDValue *sv, FVECT ioVec, double randX, int
 	randX -= rdiff;
 					/* diffuse transmission? */
 	if ((sflags & SDsampDf+SDsampT) == SDsampDf+SDsampT) {
-		if (randX < sd->tLamb.cieY) {
-			sv->spec = sd->tLamb.spec;
-			SDdiffuseSamp(ioVec, !inFront, randX/sd->tLamb.cieY);
+		const SDValue	*sdt = inFront ? &sd->tLambFront : &sd->tLambBack;
+		if (randX < sdt->cieY) {
+			sv->spec = sdt->spec;
+			SDdiffuseSamp(ioVec, !inFront, randX/sdt->cieY);
 			goto done;
 		}
-		randX -= sd->tLamb.cieY;
+		randX -= sdt->cieY;
 	}
 					/* else one of cumulative dist. */
-	for (i = 0; i < n && randX < cdarr[i]->cTotal; i++)
+	for (i = 0; i < n && randX >= cdarr[i]->cTotal; i++)
 		randX -= cdarr[i]->cTotal;
 	if (i >= n)
 		return SDEinternal;
@@ -815,8 +823,7 @@ SDsampBSDF(SDValue *sv, FVECT ioVec, double randX, int
 done:
 	if (cdarr != NULL)
 		free(cdarr);
-					/* make sure everything is set */
-	c_ccvt(&sv->spec, C_CSXY+C_CSSPEC);
+	c_ccvt(&sv->spec, C_CSXY);	/* make sure (x,y) is set */
 	return SDEnone;
 }