--- ray/src/common/bsdf.c	2011/01/06 04:40:22	2.12
+++ ray/src/common/bsdf.c	2012/09/02 15:33:15	2.42
@@ -1,15 +1,888 @@
 #ifndef lint
-static const char RCSid[] = "$Id: bsdf.c,v 2.12 2011/01/06 04:40:22 greg Exp $";
+static const char RCSid[] = "$Id: bsdf.c,v 2.42 2012/09/02 15:33:15 greg Exp $";
 #endif
 /*
+ *  bsdf.c
+ *  
+ *  Definitions for bidirectional scattering distribution functions.
+ *
+ *  Created by Greg Ward on 1/10/11.
+ *
+ */
+
+#define	_USE_MATH_DEFINES
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#include <ctype.h>
+#include "ezxml.h"
+#include "hilbert.h"
+#include "bsdf.h"
+#include "bsdf_m.h"
+#include "bsdf_t.h"
+
+/* English ASCII strings corresponding to ennumerated errors */
+const char		*SDerrorEnglish[] = {
+				"No error",
+				"Memory error",
+				"File input/output error",
+				"File format error",
+				"Illegal argument",
+				"Invalid data",
+				"Unsupported feature",
+				"Internal program error",
+				"Unknown error"
+			};
+
+/* Additional information on last error (ASCII English) */
+char			SDerrorDetail[256];
+
+/* Empty distribution for getCDist() calls that fail for some reason */
+const SDCDst		SDemptyCD;
+
+/* Cache of loaded BSDFs */
+struct SDCache_s	*SDcacheList = NULL;
+
+/* Retain BSDFs in cache list */
+int			SDretainSet = SDretainNone;
+
+/* Report any error to the indicated stream (in English) */
+SDError
+SDreportEnglish(SDError ec, FILE *fp)
+{
+	if (!ec)
+		return SDEnone;
+	if ((ec < SDEnone) | (ec > SDEunknown)) {
+		SDerrorDetail[0] = '\0';
+		ec = SDEunknown;
+	}
+	if (fp == NULL)
+		return ec;
+	fputs(SDerrorEnglish[ec], fp);
+	if (SDerrorDetail[0]) {
+		fputs(": ", fp);
+		fputs(SDerrorDetail, fp);
+	}
+	fputc('\n', fp);
+	if (fp != stderr)
+		fflush(fp);
+	return ec;
+}
+
+static double
+to_meters(		/* return factor to convert given unit to meters */
+	const char *unit
+)
+{
+	if (unit == NULL) return(1.);		/* safe assumption? */
+	if (!strcasecmp(unit, "Meter")) return(1.);
+	if (!strcasecmp(unit, "Foot")) return(.3048);
+	if (!strcasecmp(unit, "Inch")) return(.0254);
+	if (!strcasecmp(unit, "Centimeter")) return(.01);
+	if (!strcasecmp(unit, "Millimeter")) return(.001);
+	sprintf(SDerrorDetail, "Unknown dimensional unit '%s'", unit);
+	return(-1.);
+}
+
+/* Load geometric dimensions and description (if any) */
+static SDError
+SDloadGeometry(SDData *sd, ezxml_t wdb)
+{
+	ezxml_t		geom;
+	double		cfact;
+	const char	*fmt, *mgfstr;
+
+	if (wdb == NULL)		/* no geometry section? */
+		return SDEnone;
+	if ((geom = ezxml_child(wdb, "Name")) != NULL) {
+		strncpy(sd->matn, ezxml_txt(geom), SDnameLn);
+		if (sd->matn[SDnameLn-1])
+			strcpy(sd->matn+(SDnameLn-4), "...");
+	}
+	if ((geom = ezxml_child(wdb, "Manufacturer")) != NULL) {
+		strncpy(sd->makr, ezxml_txt(geom), SDnameLn);
+		if (sd->makr[SDnameLn-1])
+			strcpy(sd->makr+(SDnameLn-4), "...");
+	}
+	sd->dim[0] = sd->dim[1] = sd->dim[2] = .0;
+	SDerrorDetail[0] = '\0';
+	if ((geom = ezxml_child(wdb, "Width")) != NULL)
+		sd->dim[0] = atof(ezxml_txt(geom)) *
+				to_meters(ezxml_attr(geom, "unit"));
+	if ((geom = ezxml_child(wdb, "Height")) != NULL)
+		sd->dim[1] = atof(ezxml_txt(geom)) *
+				to_meters(ezxml_attr(geom, "unit"));
+	if ((geom = ezxml_child(wdb, "Thickness")) != NULL)
+		sd->dim[2] = atof(ezxml_txt(geom)) *
+				to_meters(ezxml_attr(geom, "unit"));
+	if ((sd->dim[0] < 0) | (sd->dim[1] < 0) | (sd->dim[2] < 0)) {
+		if (!SDerrorDetail[0])
+			sprintf(SDerrorDetail, "Negative dimension in \"%s\"",
+						sd->name);
+		return SDEdata;
+	}
+	if ((geom = ezxml_child(wdb, "Geometry")) == NULL ||
+			(mgfstr = ezxml_txt(geom)) == NULL)
+		return SDEnone;
+	while (isspace(*mgfstr))
+		++mgfstr;
+	if (!*mgfstr)
+		return SDEnone;
+	if ((fmt = ezxml_attr(geom, "format")) != NULL &&
+			strcasecmp(fmt, "MGF")) {
+		sprintf(SDerrorDetail,
+			"Unrecognized geometry format '%s' in \"%s\"",
+					fmt, sd->name);
+		return SDEsupport;
+	}
+	cfact = to_meters(ezxml_attr(geom, "unit"));
+	if (cfact <= 0)
+		return SDEformat;
+	sd->mgf = (char *)malloc(strlen(mgfstr)+32);
+	if (sd->mgf == NULL) {
+		strcpy(SDerrorDetail, "Out of memory in SDloadGeometry");
+		return SDEmemory;
+	}
+	if (cfact < 0.99 || cfact > 1.01)
+		sprintf(sd->mgf, "xf -s %.5f\n%s\nxf\n", cfact, mgfstr);
+	else
+		strcpy(sd->mgf, mgfstr);
+	return SDEnone;
+}
+
+/* Load a BSDF struct from the given file (free first and keep name) */
+SDError
+SDloadFile(SDData *sd, const char *fname)
+{
+	SDError		lastErr;
+	ezxml_t		fl, wtl;
+
+	if ((sd == NULL) | (fname == NULL || !*fname))
+		return SDEargument;
+				/* free old data, keeping name */
+	SDfreeBSDF(sd);
+				/* parse XML file */
+	fl = ezxml_parse_file(fname);
+	if (fl == NULL) {
+		sprintf(SDerrorDetail, "Cannot open BSDF \"%s\"", fname);
+		return SDEfile;
+	}
+	if (ezxml_error(fl)[0]) {
+		sprintf(SDerrorDetail, "BSDF \"%s\" %s", fname, ezxml_error(fl));
+		ezxml_free(fl);
+		return SDEformat;
+	}
+	if (strcmp(ezxml_name(fl), "WindowElement")) {
+		sprintf(SDerrorDetail,
+			"BSDF \"%s\": top level node not 'WindowElement'",
+				sd->name);
+		ezxml_free(fl);
+		return SDEformat;
+	}
+	wtl = ezxml_child(ezxml_child(fl, "Optical"), "Layer");
+	if (wtl == NULL) {
+		sprintf(SDerrorDetail, "BSDF \"%s\": no optical layers'",
+				sd->name);
+		ezxml_free(fl);
+		return SDEformat;
+	}
+				/* load geometry if present */
+	lastErr = SDloadGeometry(sd, ezxml_child(wtl, "Material"));
+	if (lastErr) {
+		ezxml_free(fl);
+		return lastErr;
+	}
+				/* try loading variable resolution data */
+	lastErr = SDloadTre(sd, wtl);
+				/* check our result */
+	if (lastErr == SDEsupport)	/* try matrix BSDF if not tree data */
+		lastErr = SDloadMtx(sd, wtl);
+		
+				/* done with XML file */
+	ezxml_free(fl);
+	
+	if (lastErr) {		/* was there a load error? */
+		SDfreeBSDF(sd);
+		return lastErr;
+	}
+				/* remove any insignificant components */
+	if (sd->rf != NULL && sd->rf->maxHemi <= .001) {
+		SDfreeSpectralDF(sd->rf); sd->rf = NULL;
+	}
+	if (sd->rb != NULL && sd->rb->maxHemi <= .001) {
+		SDfreeSpectralDF(sd->rb); sd->rb = NULL;
+	}
+	if (sd->tf != NULL && sd->tf->maxHemi <= .001) {
+		SDfreeSpectralDF(sd->tf); sd->tf = NULL;
+	}
+	if (sd->tb != NULL && sd->tb->maxHemi <= .001) {
+		SDfreeSpectralDF(sd->tb); sd->tb = NULL;
+	}
+				/* return success */
+	return SDEnone;
+}
+
+/* Allocate new spectral distribution function */
+SDSpectralDF *
+SDnewSpectralDF(int nc)
+{
+	SDSpectralDF	*df;
+	
+	if (nc <= 0) {
+		strcpy(SDerrorDetail, "Zero component spectral DF request");
+		return NULL;
+	}
+	df = (SDSpectralDF *)malloc(sizeof(SDSpectralDF) +
+					(nc-1)*sizeof(SDComponent));
+	if (df == NULL) {
+		sprintf(SDerrorDetail,
+				"Cannot allocate %d component spectral DF", nc);
+		return NULL;
+	}
+	df->minProjSA = .0;
+	df->maxHemi = .0;
+	df->ncomp = nc;
+	memset(df->comp, 0, nc*sizeof(SDComponent));
+	return df;
+}
+
+/* Add component(s) to spectral distribution function */
+SDSpectralDF *
+SDaddComponent(SDSpectralDF *odf, int nadd)
+{
+	SDSpectralDF	*df;
+
+	if (odf == NULL)
+		return SDnewSpectralDF(nadd);
+	if (nadd <= 0)
+		return odf;
+	df = (SDSpectralDF *)realloc(odf, sizeof(SDSpectralDF) +
+				(odf->ncomp+nadd-1)*sizeof(SDComponent));
+	if (df == NULL) {
+		sprintf(SDerrorDetail,
+			"Cannot add %d component(s) to spectral DF", nadd);
+		SDfreeSpectralDF(odf);
+		return NULL;
+	}
+	memset(df->comp+df->ncomp, 0, nadd*sizeof(SDComponent));
+	df->ncomp += nadd;
+	return df;
+}
+
+/* Free cached cumulative distributions for BSDF component */
+void
+SDfreeCumulativeCache(SDSpectralDF *df)
+{
+	int	n;
+	SDCDst	*cdp;
+
+	if (df == NULL)
+		return;
+	for (n = df->ncomp; n-- > 0; )
+		while ((cdp = df->comp[n].cdList) != NULL) {
+			df->comp[n].cdList = cdp->next;
+			free(cdp);
+		}
+}
+
+/* Free a spectral distribution function */
+void
+SDfreeSpectralDF(SDSpectralDF *df)
+{
+	int	n;
+
+	if (df == NULL)
+		return;
+	SDfreeCumulativeCache(df);
+	for (n = df->ncomp; n-- > 0; )
+		if (df->comp[n].dist != NULL)
+			(*df->comp[n].func->freeSC)(df->comp[n].dist);
+	free(df);
+}
+
+/* Shorten file path to useable BSDF name, removing suffix */
+void
+SDclipName(char *res, const char *fname)
+{
+	const char	*cp, *dot = NULL;
+	
+	for (cp = fname; *cp; cp++)
+		if (*cp == '.')
+			dot = cp;
+	if ((dot == NULL) | (dot < fname+2))
+		dot = cp;
+	if (dot - fname >= SDnameLn)
+		fname = dot - SDnameLn + 1;
+	while (fname < dot)
+		*res++ = *fname++;
+	*res = '\0';
+}
+
+/* Initialize an unused BSDF struct (simply clears to zeroes) */
+void
+SDclearBSDF(SDData *sd, const char *fname)
+{
+	if (sd == NULL)
+		return;
+	memset(sd, 0, sizeof(SDData));
+	if (fname == NULL)
+		return;
+	SDclipName(sd->name, fname);
+}
+
+/* Free data associated with BSDF struct */
+void
+SDfreeBSDF(SDData *sd)
+{
+	if (sd == NULL)
+		return;
+	if (sd->mgf != NULL) {
+		free(sd->mgf);
+		sd->mgf = NULL;
+	}
+	if (sd->rf != NULL) {
+		SDfreeSpectralDF(sd->rf);
+		sd->rf = NULL;
+	}
+	if (sd->rb != NULL) {
+		SDfreeSpectralDF(sd->rb);
+		sd->rb = NULL;
+	}
+	if (sd->tf != NULL) {
+		SDfreeSpectralDF(sd->tf);
+		sd->tf = NULL;
+	}
+	if (sd->tb != NULL) {
+		SDfreeSpectralDF(sd->tb);
+		sd->tb = NULL;
+	}
+	sd->rLambFront.cieY = .0;
+	sd->rLambFront.spec.flags = 0;
+	sd->rLambBack.cieY = .0;
+	sd->rLambBack.spec.flags = 0;
+	sd->tLamb.cieY = .0;
+	sd->tLamb.spec.flags = 0;
+}
+
+/* Find writeable BSDF by name, or allocate new cache entry if absent */
+SDData *
+SDgetCache(const char *bname)
+{
+	struct SDCache_s	*sdl;
+	char			sdnam[SDnameLn];
+
+	if (bname == NULL)
+		return NULL;
+
+	SDclipName(sdnam, bname);
+	for (sdl = SDcacheList; sdl != NULL; sdl = sdl->next)
+		if (!strcmp(sdl->bsdf.name, sdnam)) {
+			sdl->refcnt++;
+			return &sdl->bsdf;
+		}
+
+	sdl = (struct SDCache_s *)calloc(1, sizeof(struct SDCache_s));
+	if (sdl == NULL)
+		return NULL;
+
+	strcpy(sdl->bsdf.name, sdnam);
+	sdl->next = SDcacheList;
+	SDcacheList = sdl;
+
+	sdl->refcnt = 1;
+	return &sdl->bsdf;
+}
+
+/* Get loaded BSDF from cache (or load and cache it on first call) */
+/* Report any problem to stderr and return NULL on failure */
+const SDData *
+SDcacheFile(const char *fname)
+{
+	SDData		*sd;
+	SDError		ec;
+	
+	if (fname == NULL || !*fname)
+		return NULL;
+	SDerrorDetail[0] = '\0';
+	if ((sd = SDgetCache(fname)) == NULL) {
+		SDreportEnglish(SDEmemory, stderr);
+		return NULL;
+	}
+	if (!SDisLoaded(sd) && (ec = SDloadFile(sd, fname))) {
+		SDreportEnglish(ec, stderr);
+		SDfreeCache(sd);
+		return NULL;
+	}
+	return sd;
+}
+
+/* Free a BSDF from our cache (clear all if NULL) */
+void
+SDfreeCache(const SDData *sd)
+{
+	struct SDCache_s	*sdl, *sdLast = NULL;
+
+	if (sd == NULL) {		/* free entire list */
+		while ((sdl = SDcacheList) != NULL) {
+			SDcacheList = sdl->next;
+			SDfreeBSDF(&sdl->bsdf);
+			free(sdl);
+		}
+		return;
+	}
+	for (sdl = SDcacheList; sdl != NULL; sdl = (sdLast=sdl)->next)
+		if (&sdl->bsdf == sd)
+			break;
+	if (sdl == NULL || (sdl->refcnt -= (sdl->refcnt > 0)))
+		return;			/* missing or still in use */
+					/* keep unreferenced data? */
+	if (SDisLoaded(sd) && SDretainSet) {
+		if (SDretainSet == SDretainAll)
+			return;		/* keep everything */
+					/* else free cumulative data */
+		SDfreeCumulativeCache(sd->rf);
+		SDfreeCumulativeCache(sd->rb);
+		SDfreeCumulativeCache(sd->tf);
+		SDfreeCumulativeCache(sd->tb);
+		return;
+	}
+					/* remove from list and free */
+	if (sdLast == NULL)
+		SDcacheList = sdl->next;
+	else
+		sdLast->next = sdl->next;
+	SDfreeBSDF(&sdl->bsdf);
+	free(sdl);
+}
+
+/* Sample an individual BSDF component */
+SDError
+SDsampComponent(SDValue *sv, FVECT ioVec, double randX, SDComponent *sdc)
+{
+	float		coef[SDmaxCh];
+	SDError		ec;
+	FVECT		inVec;
+	const SDCDst	*cd;
+	double		d;
+	int		n;
+					/* check arguments */
+	if ((sv == NULL) | (ioVec == NULL) | (sdc == NULL))
+		return SDEargument;
+					/* get cumulative distribution */
+	VCOPY(inVec, ioVec);
+	cd = (*sdc->func->getCDist)(inVec, sdc);
+	if (cd == NULL)
+		return SDEmemory;
+	if (cd->cTotal <= 1e-6) {	/* anything to sample? */
+		sv->spec = c_dfcolor;
+		sv->cieY = .0;
+		memset(ioVec, 0, 3*sizeof(double));
+		return SDEnone;
+	}
+	sv->cieY = cd->cTotal;
+					/* compute sample direction */
+	ec = (*sdc->func->sampCDist)(ioVec, randX, cd);
+	if (ec)
+		return ec;
+					/* get BSDF color */
+	n = (*sdc->func->getBSDFs)(coef, ioVec, inVec, sdc);
+	if (n <= 0) {
+		strcpy(SDerrorDetail, "BSDF sample value error");
+		return SDEinternal;
+	}
+	sv->spec = sdc->cspec[0];
+	d = coef[0];
+	while (--n) {
+		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);
+	return SDEnone;
+}
+
+#define	MS_MAXDIM	15
+
+/* Convert 1-dimensional random variable to N-dimensional */
+void
+SDmultiSamp(double t[], int n, double randX)
+{
+	unsigned	nBits;
+	double		scale;
+	bitmask_t	ndx, coord[MS_MAXDIM];
+
+	if (n <= 0)			/* check corner cases */
+		return;
+	if (randX < 0) randX = 0;
+	else if (randX >= 1.) randX = 0.999999999999999;
+	if (n == 1) {
+		t[0] = randX;
+		return;
+	}
+	while (n > MS_MAXDIM)		/* punt for higher dimensions */
+		t[--n] = rand()*(1./(RAND_MAX+.5));
+	nBits = (8*sizeof(bitmask_t) - 1) / n;
+	ndx = randX * (double)((bitmask_t)1 << (nBits*n));
+					/* get coordinate on Hilbert curve */
+	hilbert_i2c(n, nBits, ndx, coord);
+					/* convert back to [0,1) range */
+	scale = 1. / (double)((bitmask_t)1 << nBits);
+	while (n--)
+		t[n] = scale * ((double)coord[n] + rand()*(1./(RAND_MAX+.5)));
+}
+
+#undef MS_MAXDIM
+
+/* Generate diffuse hemispherical sample */
+static void
+SDdiffuseSamp(FVECT outVec, int outFront, double randX)
+{
+					/* convert to position on hemisphere */
+	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]);
+	if (!outFront)			/* going out back? */
+		outVec[2] = -outVec[2];
+}
+
+/* Query projected solid angle coverage for non-diffuse BSDF direction */
+SDError
+SDsizeBSDF(double *projSA, const FVECT v1, const RREAL *v2,
+				int qflags, const SDData *sd)
+{
+	SDSpectralDF	*rdf, *tdf;
+	SDError		ec;
+	int		i;
+					/* check arguments */
+	if ((projSA == NULL) | (v1 == NULL) | (sd == NULL))
+		return SDEargument;
+					/* initialize extrema */
+	switch (qflags) {
+	case SDqueryMax:
+		projSA[0] = .0;
+		break;
+	case SDqueryMin+SDqueryMax:
+		projSA[1] = .0;
+		/* fall through */
+	case SDqueryMin:
+		projSA[0] = 10.;
+		break;
+	case 0:
+		return SDEargument;
+	}
+	if (v1[2] > 0) {		/* front surface query? */
+		rdf = sd->rf;
+		tdf = (sd->tf != NULL) ? sd->tf : sd->tb;
+	} else {
+		rdf = sd->rb;
+		tdf = (sd->tb != NULL) ? sd->tb : sd->tf;
+	}
+	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,
+						qflags, &rdf->comp[i]);
+		if (ec)
+			return ec;
+	}
+	for (i = (tdf==NULL) ? 0 : tdf->ncomp; i--; ) {
+		ec = (*tdf->comp[i].func->queryProjSA)(projSA, v1, v2,
+						qflags, &tdf->comp[i]);
+		if (ec)
+			return ec;
+	}
+	if (ec) {			/* all diffuse? */
+		projSA[0] = M_PI;
+		if (qflags == SDqueryMin+SDqueryMax)
+			projSA[1] = M_PI;
+	}
+	return SDEnone;
+}
+
+/* Return BSDF for the given incident and scattered ray vectors */
+SDError
+SDevalBSDF(SDValue *sv, const FVECT outVec, const FVECT inVec, const SDData *sd)
+{
+	int		inFront, outFront;
+	SDSpectralDF	*sdf;
+	float		coef[SDmaxCh];
+	int		nch, i;
+					/* check arguments */
+	if ((sv == NULL) | (outVec == NULL) | (inVec == NULL) | (sd == NULL))
+		return SDEargument;
+					/* whose side are we on? */
+	inFront = (inVec[2] > 0);
+	outFront = (outVec[2] > 0);
+					/* start with diffuse portion */
+	if (inFront & outFront) {
+		*sv = sd->rLambFront;
+		sdf = sd->rf;
+	} else if (!(inFront | outFront)) {
+		*sv = sd->rLambBack;
+		sdf = sd->rb;
+	} else if (inFront) {
+		*sv = sd->tLamb;
+		sdf = (sd->tf != NULL) ? sd->tf : sd->tb;
+	} else /* inBack */ {
+		*sv = sd->tLamb;
+		sdf = (sd->tb != NULL) ? sd->tb : sd->tf;
+	}
+	sv->cieY *= 1./M_PI;
+					/* add non-diffuse components */
+	i = (sdf != NULL) ? sdf->ncomp : 0;
+	while (i-- > 0) {
+		nch = (*sdf->comp[i].func->getBSDFs)(coef, outVec, inVec,
+							&sdf->comp[i]);
+		while (nch-- > 0) {
+			c_cmix(&sv->spec, sv->cieY, &sv->spec,
+					coef[nch], &sdf->comp[i].cspec[nch]);
+			sv->cieY += coef[nch];
+		}
+	}
+					/* make sure everything is set */
+	c_ccvt(&sv->spec, C_CSXY+C_CSSPEC);
+	return SDEnone;
+}
+
+/* Compute directional hemispherical scattering at this incident angle */
+double
+SDdirectHemi(const FVECT inVec, int sflags, const SDData *sd)
+{
+	double		hsum;
+	SDSpectralDF	*rdf, *tdf;
+	const SDCDst	*cd;
+	int		i;
+					/* check arguments */
+	if ((inVec == NULL) | (sd == NULL))
+		return .0;
+					/* gather diffuse components */
+	if (inVec[2] > 0) {
+		hsum = sd->rLambFront.cieY;
+		rdf = sd->rf;
+		tdf = (sd->tf != NULL) ? sd->tf : sd->tb;
+	} else /* !inFront */ {
+		hsum = sd->rLambBack.cieY;
+		rdf = sd->rb;
+		tdf = (sd->tb != NULL) ? sd->tb : sd->tf;
+	}
+	if ((sflags & SDsampDf+SDsampR) != SDsampDf+SDsampR)
+		hsum = .0;
+	if ((sflags & SDsampDf+SDsampT) == SDsampDf+SDsampT)
+		hsum += sd->tLamb.cieY;
+					/* gather non-diffuse components */
+	i = (((sflags & SDsampSp+SDsampR) == SDsampSp+SDsampR) &
+			(rdf != NULL)) ? rdf->ncomp : 0;
+	while (i-- > 0) {		/* non-diffuse reflection */
+		cd = (*rdf->comp[i].func->getCDist)(inVec, &rdf->comp[i]);
+		if (cd != NULL)
+			hsum += cd->cTotal;
+	}
+	i = (((sflags & SDsampSp+SDsampT) == SDsampSp+SDsampT) &
+			(tdf != NULL)) ? tdf->ncomp : 0;
+	while (i-- > 0) {		/* non-diffuse transmission */
+		cd = (*tdf->comp[i].func->getCDist)(inVec, &tdf->comp[i]);
+		if (cd != NULL)
+			hsum += cd->cTotal;
+	}
+	return hsum;
+}
+
+/* Sample BSDF direction based on the given random variable */
+SDError
+SDsampBSDF(SDValue *sv, FVECT ioVec, double randX, int sflags, const SDData *sd)
+{
+	SDError		ec;
+	FVECT		inVec;
+	int		inFront;
+	SDSpectralDF	*rdf, *tdf;
+	double		rdiff;
+	float		coef[SDmaxCh];
+	int		i, j, n, nr;
+	SDComponent	*sdc;
+	const SDCDst	**cdarr = NULL;
+					/* check arguments */
+	if ((sv == NULL) | (ioVec == NULL) | (sd == NULL) |
+			(randX < 0) | (randX >= 1.))
+		return SDEargument;
+					/* whose side are we on? */
+	VCOPY(inVec, ioVec);
+	inFront = (inVec[2] > 0);
+					/* remember diffuse portions */
+	if (inFront) {
+		*sv = sd->rLambFront;
+		rdf = sd->rf;
+		tdf = (sd->tf != NULL) ? sd->tf : sd->tb;
+	} else /* !inFront */ {
+		*sv = sd->rLambBack;
+		rdf = sd->rb;
+		tdf = (sd->tb != NULL) ? sd->tb : sd->tf;
+	}
+	if ((sflags & SDsampDf+SDsampR) != SDsampDf+SDsampR)
+		sv->cieY = .0;
+	rdiff = sv->cieY;
+	if ((sflags & SDsampDf+SDsampT) == SDsampDf+SDsampT)
+		sv->cieY += sd->tLamb.cieY;
+					/* gather non-diffuse components */
+	i = nr = (((sflags & SDsampSp+SDsampR) == SDsampSp+SDsampR) &
+			(rdf != NULL)) ? rdf->ncomp : 0;
+	j = (((sflags & SDsampSp+SDsampT) == SDsampSp+SDsampT) &
+			(tdf != NULL)) ? tdf->ncomp : 0;
+	n = i + j;
+	if (n > 0 && (cdarr = (const SDCDst **)malloc(n*sizeof(SDCDst *))) == NULL)
+		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;
+		}
+		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;
+		}
+		sv->cieY += cdarr[i]->cTotal;
+	}
+	if (sv->cieY <= 1e-6) {		/* anything to sample? */
+		sv->cieY = .0;
+		memset(ioVec, 0, 3*sizeof(double));
+		return SDEnone;
+	}
+					/* scale random variable */
+	randX *= sv->cieY;
+					/* diffuse reflection? */
+	if (randX < rdiff) {
+		SDdiffuseSamp(ioVec, inFront, randX/rdiff);
+		goto done;
+	}
+	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);
+			goto done;
+		}
+		randX -= sd->tLamb.cieY;
+	}
+					/* else one of cumulative dist. */
+	for (i = 0; i < n && randX < cdarr[i]->cTotal; i++)
+		randX -= cdarr[i]->cTotal;
+	if (i >= n)
+		return SDEinternal;
+					/* compute sample direction */
+	sdc = (i < nr) ? &rdf->comp[i] : &tdf->comp[i-nr];
+	ec = (*sdc->func->sampCDist)(ioVec, randX/cdarr[i]->cTotal, cdarr[i]);
+	if (ec)
+		return ec;
+					/* compute color */
+	j = (*sdc->func->getBSDFs)(coef, ioVec, inVec, sdc);
+	if (j <= 0) {
+		sprintf(SDerrorDetail, "BSDF \"%s\" sampling value error",
+				sd->name);
+		return SDEinternal;
+	}
+	sv->spec = sdc->cspec[0];
+	rdiff = coef[0];
+	while (--j) {
+		c_cmix(&sv->spec, rdiff, &sv->spec, coef[j], &sdc->cspec[j]);
+		rdiff += coef[j];
+	}
+done:
+	if (cdarr != NULL)
+		free(cdarr);
+					/* make sure everything is set */
+	c_ccvt(&sv->spec, C_CSXY+C_CSSPEC);
+	return SDEnone;
+}
+
+/* Compute World->BSDF transform from surface normal and up (Y) vector */
+SDError	
+SDcompXform(RREAL vMtx[3][3], const FVECT sNrm, const FVECT uVec)
+{
+	if ((vMtx == NULL) | (sNrm == NULL) | (uVec == NULL))
+		return SDEargument;
+	VCOPY(vMtx[2], sNrm);
+	if (normalize(vMtx[2]) == 0)
+		return SDEargument;
+	fcross(vMtx[0], uVec, vMtx[2]);
+	if (normalize(vMtx[0]) == 0)
+		return SDEargument;
+	fcross(vMtx[1], vMtx[2], vMtx[0]);
+	return SDEnone;
+}
+
+/* Compute inverse transform */
+SDError	
+SDinvXform(RREAL iMtx[3][3], RREAL vMtx[3][3])
+{
+	RREAL	mTmp[3][3];
+	double	d;
+
+	if ((iMtx == NULL) | (vMtx == NULL))
+		return SDEargument;
+					/* compute determinant */
+	mTmp[0][0] = vMtx[2][2]*vMtx[1][1] - vMtx[2][1]*vMtx[1][2];
+	mTmp[0][1] = vMtx[2][1]*vMtx[0][2] - vMtx[2][2]*vMtx[0][1];
+	mTmp[0][2] = vMtx[1][2]*vMtx[0][1] - vMtx[1][1]*vMtx[0][2];
+	d = vMtx[0][0]*mTmp[0][0] + vMtx[1][0]*mTmp[0][1] + vMtx[2][0]*mTmp[0][2];
+	if (d == 0) {
+		strcpy(SDerrorDetail, "Zero determinant in matrix inversion");
+		return SDEargument;
+	}
+	d = 1./d;			/* invert matrix */
+	mTmp[0][0] *= d; mTmp[0][1] *= d; mTmp[0][2] *= d;
+	mTmp[1][0] = d*(vMtx[2][0]*vMtx[1][2] - vMtx[2][2]*vMtx[1][0]);
+	mTmp[1][1] = d*(vMtx[2][2]*vMtx[0][0] - vMtx[2][0]*vMtx[0][2]);
+	mTmp[1][2] = d*(vMtx[1][0]*vMtx[0][2] - vMtx[1][2]*vMtx[0][0]);
+	mTmp[2][0] = d*(vMtx[2][1]*vMtx[1][0] - vMtx[2][0]*vMtx[1][1]);
+	mTmp[2][1] = d*(vMtx[2][0]*vMtx[0][1] - vMtx[2][1]*vMtx[0][0]);
+	mTmp[2][2] = d*(vMtx[1][1]*vMtx[0][0] - vMtx[1][0]*vMtx[0][1]);
+	memcpy(iMtx, mTmp, sizeof(mTmp));
+	return SDEnone;
+}
+
+/* Transform and normalize direction (column) vector */
+SDError
+SDmapDir(FVECT resVec, RREAL vMtx[3][3], const FVECT inpVec)
+{
+	FVECT	vTmp;
+
+	if ((resVec == NULL) | (inpVec == NULL))
+		return SDEargument;
+	if (vMtx == NULL) {		/* assume they just want to normalize */
+		if (resVec != inpVec)
+			VCOPY(resVec, inpVec);
+		return (normalize(resVec) > 0) ? SDEnone : SDEargument;
+	}
+	vTmp[0] = DOT(vMtx[0], inpVec);
+	vTmp[1] = DOT(vMtx[1], inpVec);
+	vTmp[2] = DOT(vMtx[2], inpVec);
+	if (normalize(vTmp) == 0)
+		return SDEargument;
+	VCOPY(resVec, vTmp);
+	return SDEnone;
+}
+
+/*################################################################*/
+/*######### DEPRECATED ROUTINES AWAITING PERMANENT REMOVAL #######*/
+
+/*
  * Routines for handling BSDF data
  */
 
 #include "standard.h"
-#include "bsdf.h"
 #include "paths.h"
-#include "ezxml.h"
-#include <ctype.h>
 
 #define MAXLATS		46		/* maximum number of latitudes */
 
@@ -66,12 +939,12 @@ 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 *
@@ -83,7 +956,7 @@ 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 *
@@ -129,7 +1002,7 @@ ab_getndx(		/* get index corresponding to the given ve
 {
 	ANGLE_BASIS  *ab = (ANGLE_BASIS *)p;
 	int	li, ndx;
-	double	pol, azi, d;
+	double	pol, azi;
 
 	if ((v[2] < -1.0) | (v[2] > 1.0))
 		return(-1);
@@ -247,22 +1120,6 @@ load_angle_basis(	/* load custom BSDF angle basis */
 }
 
 
-static double
-to_meters(		/* return factor to convert given unit to meters */
-	const char *unit
-)
-{
-	if (unit == NULL) return(1.);		/* safe assumption? */
-	if (!strcasecmp(unit, "Meter")) return(1.);
-	if (!strcasecmp(unit, "Foot")) return(.3048);
-	if (!strcasecmp(unit, "Inch")) return(.0254);
-	if (!strcasecmp(unit, "Centimeter")) return(.01);
-	if (!strcasecmp(unit, "Millimeter")) return(.001);
-	sprintf(errmsg, "unknown dimensional unit '%s'", unit);
-	error(USER, errmsg);
-}
-
-
 static void
 load_geometry(		/* load geometric dimensions and description (if any) */
 	struct BSDF_data *dp,
@@ -343,7 +1200,7 @@ load_bsdf_data(		/* load BSDF distribution for this wa
 			break;
 		}
 	if (i < 0) {
-		sprintf(errmsg, "undefined RowAngleBasis '%s'", cbasis);
+		sprintf(errmsg, "undefined RowAngleBasis '%s'", rbasis);
 		error(WARNING, errmsg);
 		return;
 	}
@@ -385,7 +1242,7 @@ check_bsdf_data(	/* check that BSDF data is sane */
 )
 {
 	double		*omega_iarr, *omega_oarr;
-	double		dom, contrib, hemi_total, full_total;
+	double		dom, hemi_total, full_total;
 	int		nneg;
 	FVECT		v;
 	int		i, o;
@@ -400,7 +1257,7 @@ check_bsdf_data(	/* check that BSDF data is sane */
 	hemi_total = .0;
 	for (i = dp->ninc; i--; ) {
 		dom = getBSDF_incohm(dp,i);
-		if (dom <= .0) {
+		if (dom <= 0) {
 			error(WARNING, "zero/negative incoming solid angle");
 			continue;
 		}
@@ -423,7 +1280,7 @@ check_bsdf_data(	/* check that BSDF data is sane */
 	hemi_total = .0;
 	for (o = dp->nout; o--; ) {
 		dom = getBSDF_outohm(dp,o);
-		if (dom <= .0) {
+		if (dom <= 0) {
 			error(WARNING, "zero/negative outgoing solid angle");
 			continue;
 		}
@@ -447,7 +1304,7 @@ check_bsdf_data(	/* check that BSDF data is sane */
 		hemi_total = .0;
 		for (o = dp->nout; o--; ) {
 			double	f = BSDF_value(dp,i,o);
-			if (f >= .0)
+			if (f >= 0)
 				hemi_total += f*omega_oarr[o];
 			else {
 				nneg += (f < -FTINY);
@@ -535,22 +1392,28 @@ load_BSDF(		/* load BSDF data from file */
 		error(WARNING, errmsg);
 		ezxml_free(fl);
 		return(NULL);
-	}		
-	load_angle_basis(ezxml_child(ezxml_child(wtl,
-				"DataDefinition"), "AngleBasis"));
+	}
+	for (wld = ezxml_child(ezxml_child(wtl,
+				"DataDefinition"), "AngleBasis");
+			wld != NULL; wld = wld->next)
+		load_angle_basis(wld);
 	dp = (struct BSDF_data *)calloc(1, sizeof(struct BSDF_data));
 	load_geometry(dp, ezxml_child(wtl, "Material"));
 	for (wld = ezxml_child(wtl, "WavelengthData");
 				wld != NULL; wld = wld->next) {
-		if (strcasecmp(ezxml_txt(ezxml_child(wld,"Wavelength")), "Visible"))
+		if (strcasecmp(ezxml_txt(ezxml_child(wld,"Wavelength")),
+				"Visible"))
 			continue;
-		wdb = ezxml_child(wld, "WavelengthDataBlock");
-		if (wdb == NULL) continue;
-		if (strcasecmp(ezxml_txt(ezxml_child(wdb,"WavelengthDataDirection")),
+		for (wdb = ezxml_child(wld, "WavelengthDataBlock");
+				wdb != NULL; wdb = wdb->next)
+			if (!strcasecmp(ezxml_txt(ezxml_child(wdb,
+					"WavelengthDataDirection")),
 					"Transmission Front"))
-			continue;
-		load_bsdf_data(dp, wdb);	/* load front BTDF */
-		break;				/* ignore the rest */
+				break;
+		if (wdb != NULL) {		/* load front BTDF */
+			load_bsdf_data(dp, wdb);
+			break;			/* ignore the rest */
+		}
 	}
 	ezxml_free(fl);				/* done with XML file */
 	if (!check_bsdf_data(dp)) {
@@ -594,7 +1457,7 @@ r_BSDF_incvec(		/* compute random input vector at give
 	if (!getBSDF_incvec(v, b, i))
 		return(0);
 	rad = sqrt(getBSDF_incohm(b, i) / PI);
-	multisamp(pert, 3, rv);
+	SDmultiSamp(pert, 3, rv);
 	for (j = 0; j < 3; j++)
 		v[j] += rad*(2.*pert[j] - 1.);
 	if (xm != NULL)
@@ -619,7 +1482,7 @@ r_BSDF_outvec(		/* compute random output vector at giv
 	if (!getBSDF_outvec(v, b, o))
 		return(0);
 	rad = sqrt(getBSDF_outohm(b, o) / PI);
-	multisamp(pert, 3, rv);
+	SDmultiSamp(pert, 3, rv);
 	for (j = 0; j < 3; j++)
 		v[j] += rad*(2.*pert[j] - 1.);
 	if (xm != NULL)
@@ -726,3 +1589,6 @@ getBSDF_xfm(		/* compute BSDF orient. -> world orient.
 	}
 	return(1);
 }
+
+/*######### END DEPRECATED ROUTINES #######*/
+/*################################################################*/