--- ray/src/cv/bsdf2rad.c	2017/04/09 21:39:26	2.16
+++ ray/src/cv/bsdf2rad.c	2021/12/07 23:55:02	2.39
@@ -1,21 +1,22 @@
 #ifndef lint
-static const char RCSid[] = "$Id: bsdf2rad.c,v 2.16 2017/04/09 21:39:26 greg Exp $";
+static const char RCSid[] = "$Id: bsdf2rad.c,v 2.39 2021/12/07 23:55:02 greg Exp $";
 #endif
 /*
  *  Plot 3-D BSDF output based on scattering interpolant or XML representation
  */
 
-#include <stdio.h>
-#include <string.h>
 #include <stdlib.h>
+#include "rtio.h"
 #include "paths.h"
 #include "rtmath.h"
-#include "resolu.h"
 #include "bsdfrep.h"
 
-#define NINCIDENT	25		/* number of samples/hemisphere */
-
+#ifndef NINCIDENT
+#define NINCIDENT	37		/* number of samples/hemisphere */
+#endif
+#ifndef GRIDSTEP
 #define	GRIDSTEP	2		/* our grid step size */
+#endif
 #define SAMPRES		(GRIDRES/GRIDSTEP)
 
 int	front_comp = 0;			/* front component flags (SDsamp*) */
@@ -24,50 +25,58 @@ double	overall_min = 1./PI;		/* overall minimum BSDF v
 double	min_log10;			/* smallest log10 value for plotting */
 double	overall_max = .0;		/* overall maximum BSDF value */
 
-char	ourTempDir[TEMPLEN] = "";	/* our temporary directory */
+char	ourTempDir[TEMPLEN+1] = "";	/* our temporary directory */
 
-const FVECT	Xaxis = {1., 0., 0.};
-const FVECT	Yaxis = {0., 1., 0.};
-const FVECT	Zaxis = {0., 0., 1.};
-
-const char	frpref[] = "frefl";
-const char	ftpref[] = "ftrans";
-const char	brpref[] = "brefl";
-const char	btpref[] = "btrans";
+const char	frpref[] = "rf";
+const char	ftpref[] = "tf";
+const char	brpref[] = "rb";
+const char	btpref[] = "tb";
 const char	dsuffix[] = ".txt";
 
-const char	sph_mat[] = "BSDFmat";
+const char	sph_fmat[] = "fBSDFmat";
+const char	sph_bmat[] = "bBSDFmat";
 const double	sph_rad = 10.;
 const double	sph_xoffset = 15.;
 
 #define bsdf_rad	(sph_rad*.25)
 #define arrow_rad	(bsdf_rad*.015)
 
-#define	FEQ(a,b)	((a)-(b) <= 1e-7 && (b)-(a) <= 1e-7)
+#define	set_minlog()	overall_min = (overall_min < 1e-5) ? 1e-5 : overall_min; \
+				min_log10 = log10(overall_min) - .1
 
-#define	set_minlog()	(min_log10 = log10(overall_min + 1e-5) - .1)
-
 char	*progname;
 
 /* Get Fibonacci sphere vector (0 to NINCIDENT-1) */
-static void
+static RREAL *
 get_ivector(FVECT iv, int i)
 {
-	const double	zstep = 1./(2*NINCIDENT-1);
 	const double	phistep = PI*(3. - 2.236067978);
 	double		r;
 
-	iv[2] = 1. - (i+.5)*zstep;
+	iv[2] = 1. - (i+.5)*(1./NINCIDENT);
 	r = sqrt(1. - iv[2]*iv[2]);
 	iv[0] = r * cos((i+1.)*phistep);
 	iv[1] = r * sin((i+1.)*phistep);
+
+	return(iv);
 }
 
+/* Convert incident vector into sphere position */
+static RREAL *
+cvt_sposition(FVECT sp, const FVECT iv, int inc_side)
+{
+	sp[0] = -iv[0]*sph_rad + inc_side*sph_xoffset;
+	sp[1] = -iv[1]*sph_rad;
+	sp[2] = iv[2]*sph_rad;
+
+	return(sp);
+}
+
 /* Get temporary file name */
 static char *
 tfile_name(const char *prefix, const char *suffix, int i)
 {
-	static char	buf[128];
+	static char	buf[256];
 
 	if (!ourTempDir[0]) {		/* create temporary directory */
 		mktemp(strcpy(ourTempDir,TEMPLATE));
@@ -135,8 +144,8 @@ plotBSDF(const char *fname, const FVECT ivec, int dfl,
 		SDValue	sval;
 		double	bsdf;
 		ovec_from_pos(ovec, i*GRIDSTEP, j*GRIDSTEP);
-		if (SDreportError(SDevalBSDF(&sval, ovec,
-						ivec, sd), stderr))
+		if (SDreportError(SDevalBSDF(&sval, ivec,
+						ovec, sd), stderr))
 			return(0);
 		if (sval.cieY > overall_max)
 			overall_max = sval.cieY;
@@ -249,7 +258,7 @@ build_wRBF(void)
 		RBFNODE	*rbf;
 		get_ivector(ivec, i);
 		if (input_orient < 0) {
-			ivec[0] = -ivec[0]; ivec[1] = -ivec[1]; ivec[2] = -ivec[2];
+			ivec[0] = -ivec[0]; ivec[2] = -ivec[2];
 		}
 		rbf = advect_rbf(ivec, 15000);
 		if (!plotRBF(tfile_name(pref, dsuffix, i), rbf))
@@ -261,34 +270,32 @@ build_wRBF(void)
 
 /* Put out mirror arrow for the given incident vector */
 static void
-put_mirror_arrow(const FVECT ivec, int inc_side)
+put_mirror_arrow(const FVECT origin, const FVECT nrm)
 {
 	const double	arrow_len = 1.2*bsdf_rad;
 	const double	tip_len = 0.2*bsdf_rad;
-	FVECT		origin, refl;
+	static int	cnt = 1;
+	FVECT		refl;
 	int		i;
 
-	for (i = 3; i--; ) origin[i] = ivec[i]*sph_rad;
-	origin[0] -= inc_side*sph_xoffset;
+	refl[0] = 2.*nrm[2]*nrm[0];
+	refl[1] = 2.*nrm[2]*nrm[1];
+	refl[2] = 2.*nrm[2]*nrm[2] - 1.;
 
-	refl[0] = 2.*ivec[2]*ivec[0];
-	refl[1] = 2.*ivec[2]*ivec[1];
-	refl[2] = 2.*ivec[2]*ivec[2] - 1.;
-
-	printf("\n# Mirror arrow\n");
-	printf("\narrow_mat cylinder inc_dir\n0\n0\n7");
+	printf("\n# Mirror arrow #%d\n", cnt);
+	printf("\nshaft_mat cylinder inc_dir%d\n0\n0\n7", cnt);
 	printf("\n\t%f %f %f\n\t%f %f %f\n\t%f\n",
 			origin[0], origin[1], origin[2]+arrow_len,
 			origin[0], origin[1], origin[2],
 			arrow_rad);
-	printf("\narrow_mat cylinder mir_dir\n0\n0\n7");
+	printf("\nshaft_mat cylinder mir_dir%d\n0\n0\n7", cnt);
 	printf("\n\t%f %f %f\n\t%f %f %f\n\t%f\n",
 			origin[0], origin[1], origin[2],
 			origin[0] + arrow_len*refl[0],
 			origin[1] + arrow_len*refl[1],
 			origin[2] + arrow_len*refl[2],
 			arrow_rad);
-	printf("\narrow_mat cone mir_tip\n0\n0\n8");
+	printf("\ntip_mat cone mir_tip%d\n0\n0\n8", cnt);
 	printf("\n\t%f %f %f\n\t%f %f %f\n\t%f 0\n",
 			origin[0] + (arrow_len-.5*tip_len)*refl[0],
 			origin[1] + (arrow_len-.5*tip_len)*refl[1],
@@ -297,31 +304,30 @@ put_mirror_arrow(const FVECT ivec, int inc_side)
 			origin[1] + (arrow_len+.5*tip_len)*refl[1],
 			origin[2] + (arrow_len+.5*tip_len)*refl[2],
 			2.*arrow_rad);
+	++cnt;
 }
 
 /* Put out transmitted direction arrow for the given incident vector */
 static void
-put_trans_arrow(const FVECT ivec, int inc_side)
+put_trans_arrow(const FVECT origin)
 {
 	const double	arrow_len = 1.2*bsdf_rad;
 	const double	tip_len = 0.2*bsdf_rad;
-	FVECT		origin;
+	static int	cnt = 1;
 	int		i;
 
-	for (i = 3; i--; ) origin[i] = ivec[i]*sph_rad;
-	origin[0] -= inc_side*sph_xoffset;
-
-	printf("\n# Transmission arrow\n");
-	printf("\narrow_mat cylinder trans_dir\n0\n0\n7");
+	printf("\n# Transmission arrow #%d\n", cnt);
+	printf("\nshaft_mat cylinder trans_dir%d\n0\n0\n7", cnt);
 	printf("\n\t%f %f %f\n\t%f %f %f\n\t%f\n",
 			origin[0], origin[1], origin[2],
 			origin[0], origin[1], origin[2]-arrow_len,
 			arrow_rad);
-	printf("\narrow_mat cone trans_tip\n0\n0\n8");
+	printf("\ntip_mat cone trans_tip%d\n0\n0\n8", cnt);
 	printf("\n\t%f %f %f\n\t%f %f %f\n\t%f 0\n",
 			origin[0], origin[1], origin[2]-arrow_len+.5*tip_len,
 			origin[0], origin[1], origin[2]-arrow_len-.5*tip_len,
-			2.*arrow_rad);	
+			2.*arrow_rad);
+	++cnt;
 }
 
 /* Compute rotation (x,y,z) => (xp,yp,zp) */
@@ -340,19 +346,19 @@ addrot(char *xf, const FVECT xp, const FVECT yp, const
 		return(4);
 	}
 	theta = atan2(yp[2], zp[2]);
-	if (!FEQ(theta,0.0)) {
+	if (!FABSEQ(theta,0.0)) {
 		sprintf(xf, " -rx %f", theta*(180./PI));
 		while (*xf) ++xf;
 		n += 2;
 	}
 	theta = Asin(-xp[2]);
-	if (!FEQ(theta,0.0)) {
+	if (!FABSEQ(theta,0.0)) {
 		sprintf(xf, " -ry %f", theta*(180./PI));
 		while (*xf) ++xf;
 		n += 2;
 	}
 	theta = atan2(xp[1], xp[0]);
-	if (!FEQ(theta,0.0)) {
+	if (!FABSEQ(theta,0.0)) {
 		sprintf(xf, " -rz %f", theta*(180./PI));
 		/* while (*xf) ++xf; */
 		n += 2;
@@ -365,122 +371,86 @@ static int
 put_BSDFs(void)
 {
 	const double	scalef = bsdf_rad/(log10(overall_max) - min_log10);
-	FVECT		ivec;
+	FVECT		ivec, sorg, nrm, upv;
 	RREAL		vMtx[3][3];
 	char		*fname;
 	char		cmdbuf[256];
-	char		xfargs[128];
-	int		nxfa;
+	char		rotargs[64];
+	int		nrota;
 	int		i;
 
 	printf("\n# Gensurf output corresponding to %d incident directions\n",
 			NINCIDENT);
 
-	printf("\nvoid glow arrow_glow\n0\n0\n4 1 0 1 0\n");
-	printf("\nvoid mixfunc arrow_mat\n4 arrow_glow void .5 .\n0\n0\n");
+	printf("\nvoid glow tip_mat\n0\n0\n4 1 0 1 0\n");
+	printf("\nvoid mixfunc shaft_mat\n4 tip_mat void 0.25 .\n0\n0\n");
 
-	if (front_comp & SDsampR)
-		for (i = 0; i < NINCIDENT; i++) {
-			get_ivector(ivec, i);
-			put_mirror_arrow(ivec, 1);
-			sprintf(xfargs, "-s %f -t %f %f %f", bsdf_rad,
-					ivec[0]*sph_rad - sph_xoffset,
-					ivec[1]*sph_rad, ivec[2]*sph_rad);
-			nxfa = 6;
+	for (i = 0; i < NINCIDENT; i++) {
+		get_ivector(ivec, i);
+		nrm[0] = -ivec[0]; nrm[1] = -ivec[1]; nrm[2] = ivec[2];
+		upv[0] = nrm[0]*nrm[1]*(nrm[2] - 1.);
+		upv[1] = nrm[0]*nrm[0] + nrm[1]*nrm[1]*nrm[2];
+		upv[2] = -nrm[1]*(nrm[0]*nrm[0] + nrm[1]*nrm[1]);
+		if (SDcompXform(vMtx, nrm, upv) != SDEnone)
+			continue;
+		nrota = addrot(rotargs, vMtx[0], vMtx[1], vMtx[2]);
+		if (front_comp) {
+			cvt_sposition(sorg, ivec, 1);
 			printf("\nvoid colorfunc scale_pat\n");
-			printf("%d bsdf_red bsdf_grn bsdf_blu bsdf2rad.cal\n\t%s\n0\n0\n",
-					4+nxfa, xfargs);
+			printf("10 bsdf_red bsdf_grn bsdf_blu bsdf2rad.cal\n");
+			printf("\t-s %f -t %f %f %f\n0\n0\n",
+					bsdf_rad, sorg[0], sorg[1], sorg[2]);
 			printf("\nscale_pat glow scale_mat\n0\n0\n4 1 1 1 0\n");
-			SDcompXform(vMtx, ivec, Yaxis);
-			nxfa = addrot(xfargs, vMtx[0], vMtx[1], vMtx[2]);
-			sprintf(xfargs+strlen(xfargs), " -s %f -t %f %f %f",
-					scalef, ivec[0]*sph_rad - sph_xoffset,
-					ivec[1]*sph_rad, ivec[2]*sph_rad);
-			nxfa += 6;
+		}
+		if (front_comp & SDsampR) {
+			put_mirror_arrow(sorg, nrm);
 			fname = tfile_name(frpref, dsuffix, i);
-			sprintf(cmdbuf, "gensurf scale_mat %s%d %s %s %s %d %d | xform -mx -my %s",
-					frpref, i+1, fname, fname, fname, SAMPRES-1, SAMPRES-1,
-					xfargs);
+			sprintf(cmdbuf,
+		"gensurf scale_mat %s%d %s %s %s %d %d | xform %s -s %f -t %f %f %f",
+					frpref, i, fname, fname, fname, SAMPRES-1, SAMPRES-1,
+					rotargs, scalef, sorg[0], sorg[1], sorg[2]);
 			if (!run_cmd(cmdbuf))
 				return(0);
 		}
-	if (front_comp & SDsampT)
-		for (i = 0; i < NINCIDENT; i++) {
-			get_ivector(ivec, i);
-			put_trans_arrow(ivec, 1);
-			sprintf(xfargs, "-s %f -t %f %f %f", bsdf_rad,
-					ivec[0]*sph_rad - sph_xoffset,
-					ivec[1]*sph_rad, ivec[2]*sph_rad);
-			nxfa = 6;
-			printf("\nvoid colorfunc scale_pat\n");
-			printf("%d bsdf_red bsdf_grn bsdf_blu bsdf2rad.cal\n\t%s\n0\n0\n",
-					4+nxfa, xfargs);
-			printf("\nscale_pat glow scale_mat\n0\n0\n4 1 1 1 0\n");
-			SDcompXform(vMtx, ivec, Yaxis);
-			nxfa = addrot(xfargs, vMtx[0], vMtx[1], vMtx[2]);
-			sprintf(xfargs+strlen(xfargs), " -s %f -t %f %f %f",
-					scalef, ivec[0]*sph_rad - sph_xoffset,
-					ivec[1]*sph_rad, ivec[2]*sph_rad);
-			nxfa += 6;
+		if (front_comp & SDsampT) {
+			put_trans_arrow(sorg);
 			fname = tfile_name(ftpref, dsuffix, i);
-			sprintf(cmdbuf, "gensurf scale_mat %s%d %s %s %s %d %d | xform -I -mx -my %s",
-					ftpref, i+1, fname, fname, fname, SAMPRES-1, SAMPRES-1,
-					xfargs);
+			sprintf(cmdbuf,
+		"gensurf scale_mat %s%d %s %s %s %d %d | xform -I %s -s %f -t %f %f %f",
+					ftpref, i, fname, fname, fname, SAMPRES-1, SAMPRES-1,
+					rotargs, scalef, sorg[0], sorg[1], sorg[2]);
 			if (!run_cmd(cmdbuf))
 				return(0);
 		}
-	if (back_comp & SDsampR)
-		for (i = 0; i < NINCIDENT; i++) {
-			get_ivector(ivec, i);
-			put_mirror_arrow(ivec, -1);
-			fname = tfile_name(brpref, dsuffix, i);
-			sprintf(xfargs, "-s %f -t %f %f %f", bsdf_rad,
-					ivec[0]*sph_rad + sph_xoffset,
-					ivec[1]*sph_rad, ivec[2]*sph_rad);
-			nxfa = 6;
+		if (back_comp) {
+			cvt_sposition(sorg, ivec, -1);
 			printf("\nvoid colorfunc scale_pat\n");
-			printf("%d bsdf_red bsdf_grn bsdf_blu bsdf2rad.cal\n\t%s\n0\n0\n",
-					4+nxfa, xfargs);
+			printf("10 bsdf_red bsdf_grn bsdf_blu bsdf2rad.cal\n");
+			printf("\t-s %f -t %f %f %f\n0\n0\n",
+					bsdf_rad, sorg[0], sorg[1], sorg[2]);
 			printf("\nscale_pat glow scale_mat\n0\n0\n4 1 1 1 0\n");
-			SDcompXform(vMtx, ivec, Yaxis);
-			nxfa = addrot(xfargs, vMtx[0], vMtx[1], vMtx[2]);
-			sprintf(xfargs+strlen(xfargs), " -s %f -t %f %f %f",
-					scalef, ivec[0]*sph_rad + sph_xoffset,
-					ivec[1]*sph_rad, ivec[2]*sph_rad);
-			nxfa += 6;
+		}
+		if (back_comp & SDsampR) {
+			put_mirror_arrow(sorg, nrm);
 			fname = tfile_name(brpref, dsuffix, i);
-			sprintf(cmdbuf, "gensurf scale_mat %s%d %s %s %s %d %d | xform -I -ry 180 -mx -my %s",
-					brpref, i+1, fname, fname, fname, SAMPRES-1, SAMPRES-1,
-					xfargs);
+			sprintf(cmdbuf,
+		"gensurf scale_mat %s%d %s %s %s %d %d | xform -I -ry 180 %s -s %f -t %f %f %f",
+					brpref, i, fname, fname, fname, SAMPRES-1, SAMPRES-1,
+					rotargs, scalef, sorg[0], sorg[1], sorg[2]);
 			if (!run_cmd(cmdbuf))
 				return(0);
 		}
-	if (back_comp & SDsampT)
-		for (i = 0; i < NINCIDENT; i++) {
-			get_ivector(ivec, i);
-			put_trans_arrow(ivec, -1);
+		if (back_comp & SDsampT) {
+			put_trans_arrow(sorg);
 			fname = tfile_name(btpref, dsuffix, i);
-			sprintf(xfargs, "-s %f -t %f %f %f", bsdf_rad,
-					ivec[0]*sph_rad + sph_xoffset,
-					ivec[1]*sph_rad, ivec[2]*sph_rad);
-			nxfa = 6;
-			printf("\nvoid colorfunc scale_pat\n");
-			printf("%d bsdf_red bsdf_grn bsdf_blu bsdf2rad.cal\n\t%s\n0\n0\n",
-					4+nxfa, xfargs);
-			printf("\nscale_pat glow scale_mat\n0\n0\n4 1 1 1 0\n");
-			SDcompXform(vMtx, ivec, Yaxis);
-			nxfa = addrot(xfargs, vMtx[0], vMtx[1], vMtx[2]);
-			sprintf(xfargs+strlen(xfargs), " -s %f -t %f %f %f",
-					scalef, ivec[0]*sph_rad + sph_xoffset,
-					ivec[1]*sph_rad, ivec[2]*sph_rad);
-			nxfa += 6;
-			fname = tfile_name(btpref, dsuffix, i);
-			sprintf(cmdbuf, "gensurf scale_mat %s%d %s %s %s %d %d | xform -ry 180 -mx -my %s",
-					btpref, i+1, fname, fname, fname, SAMPRES-1, SAMPRES-1,
-					xfargs);
+			sprintf(cmdbuf,
+		"gensurf scale_mat %s%d %s %s %s %d %d | xform -ry 180 %s -s %f -t %f %f %f",
+					btpref, i, fname, fname, fname, SAMPRES-1, SAMPRES-1,
+					rotargs, scalef, sorg[0], sorg[1], sorg[2]);
 			if (!run_cmd(cmdbuf))
 				return(0);
 		}
+	}
 	return(1);
 }
 
@@ -494,15 +464,17 @@ put_matBSDF(const char *XMLfile)
 		printf("\n# Simplified material because we have no XML input\n");
 		printf("\nvoid brightfunc latlong\n2 latlong bsdf2rad.cal\n0\n0\n");
 		if ((front_comp|back_comp) & SDsampT)
-			printf("\nlatlong trans %s\n0\n0\n7 .75 .75 .75 0 0 .5 .8\n",
-					sph_mat);
+			printf("\nlatlong trans %s\n0\n0\n7 .75 .75 .75 0 .04 .5 .8\n",
+					sph_fmat);
 		else
 			printf("\nlatlong plastic %s\n0\n0\n5 .5 .5 .5 0 0\n",
-					sph_mat);
+					sph_fmat);
+		printf("\ninherit alias %s %s\n", sph_bmat, sph_fmat);
 		return;
 	}
 	switch (XMLfile[0]) {		/* avoid RAYPATH search */
 	case '.':
+	case '~':
 	CASEDIRSEP:
 		curdir = "";
 		break;
@@ -511,12 +483,16 @@ put_matBSDF(const char *XMLfile)
 		exit(1);
 		break;
 	}
-	printf("\n# Actual BSDF material for rendering the hemispheres\n");
-	printf("\nvoid BSDF BSDFmat\n6 0 \"%s%s\" 0 1 0 .\n0\n0\n",
+	printf("\n# Actual BSDF materials for rendering the hemispheres\n");
+	printf("\nvoid BSDF BSDF_f\n6 0 \"%s%s\" upx upy upz bsdf2rad.cal\n0\n0\n",
 			curdir, XMLfile);
 	printf("\nvoid plastic black\n0\n0\n5 0 0 0 0 0\n");
-	printf("\nvoid mixfunc %s\n4 BSDFmat black latlong bsdf2rad.cal\n0\n0\n",
-			sph_mat);
+	printf("\nvoid mixfunc %s\n4 BSDF_f black latlong bsdf2rad.cal\n0\n0\n",
+			sph_fmat);
+	printf("\nvoid BSDF BSDF_b\n8 0 \"%s%s\" upx upy upz bsdf2rad.cal -ry 180\n0\n0\n",
+			curdir, XMLfile);
+	printf("\nvoid mixfunc %s\n4 BSDF_b black latlong bsdf2rad.cal\n0\n0\n",
+			sph_bmat);
 }
 
 /* Put out overhead parallel light source */
@@ -524,7 +500,7 @@ static void
 put_source(void)
 {
 	printf("\n# Overhead parallel light source\n");
-	printf("\nvoid light bright\n0\n0\n3 1000 1000 1000\n");
+	printf("\nvoid light bright\n0\n0\n3 2500 2500 2500\n");
 	printf("\nbright source light\n0\n0\n4 0 0 1 2\n");
 	printf("\n# Material used for labels\n");
 	printf("\nvoid trans vellum\n0\n0\n7 1 1 1 0 0 .5 0\n");
@@ -534,43 +510,40 @@ put_source(void)
 static void
 put_hemispheres(void)
 {
+	const int	nsegs = 131;
+
 	printf("\n# Hemisphere(s) for showing BSDF appearance (if XML file)\n");
-	printf("\nvoid antimatter anti_sph\n2 void %s\n0\n0\n", sph_mat);
 	if (front_comp) {
-		printf("\n%s sphere Front\n0\n0\n4 %f 0 0 %f\n",
-				sph_mat, -sph_xoffset, sph_rad);
-		printf("\n!genbox anti_sph sph_eraser %f %f %f | xform -t %f %f %f\n",
-				2.02*sph_rad, 2.02*sph_rad, 1.02*sph_rad,
-				-1.01*sph_rad - sph_xoffset, -1.01*sph_rad, -1.01*sph_rad);
+		printf(
+"\n!genrev %s Front \"R*sin(A*t)\" \"R*cos(A*t)\" %d -e \"R:%g;A:%f\" -s | xform -t %g 0 0\n",
+				sph_fmat, nsegs, sph_rad, 0.5*PI, sph_xoffset);
 		printf("\nvoid brighttext front_text\n3 helvet.fnt . FRONT\n0\n");
 		printf("12\n\t%f %f 0\n\t%f 0 0\n\t0 %f 0\n\t.01 1 -.1\n",
-				-.22*sph_rad - sph_xoffset, -1.2*sph_rad,
+				-.22*sph_rad + sph_xoffset, -1.4*sph_rad,
 				.35/5.*sph_rad, -1.6*.35/5.*sph_rad);
 		printf("\nfront_text alias front_label_mat vellum\n");
 		printf("\nfront_label_mat polygon front_label\n0\n0\n12");
 		printf("\n\t%f %f 0\n\t%f %f 0\n\t%f %f 0\n\t%f %f 0\n",
-				-.25*sph_rad - sph_xoffset, -1.1*sph_rad,
-				-.25*sph_rad - sph_xoffset, (-1.2-1.6*.35/5.-.1)*sph_rad,
-				.25*sph_rad - sph_xoffset, (-1.2-1.6*.35/5.-.1)*sph_rad,
-				.25*sph_rad - sph_xoffset, -1.1*sph_rad );
+				-.25*sph_rad + sph_xoffset, -1.3*sph_rad,
+				-.25*sph_rad + sph_xoffset, (-1.4-1.6*.35/5.-.1)*sph_rad,
+				.25*sph_rad + sph_xoffset, (-1.4-1.6*.35/5.-.1)*sph_rad,
+				.25*sph_rad + sph_xoffset, -1.3*sph_rad );
 	}
 	if (back_comp) {
-		printf("\n%s bubble Back\n0\n0\n4 %f 0 0 %f\n",
-				sph_mat, sph_xoffset, sph_rad);
-		printf("\n!genbox anti_sph sph_eraser %f %f %f | xform -t %f %f %f\n",
-				2.02*sph_rad, 2.02*sph_rad, 1.02*sph_rad,
-				-1.01*sph_rad + sph_xoffset, -1.01*sph_rad, -1.01*sph_rad);
+		printf(
+"\n!genrev %s Back \"R*cos(A*t)\" \"R*sin(A*t)\" %d -e \"R:%g;A:%f\" -s | xform -t %g 0 0\n",
+				sph_bmat, nsegs, sph_rad, 0.5*PI, -sph_xoffset);
 		printf("\nvoid brighttext back_text\n3 helvet.fnt . BACK\n0\n");
 		printf("12\n\t%f %f 0\n\t%f 0 0\n\t0 %f 0\n\t.01 1 -.1\n",
-				-.22*sph_rad + sph_xoffset, -1.2*sph_rad,
+				-.22*sph_rad - sph_xoffset, -1.4*sph_rad,
 				.35/4.*sph_rad, -1.6*.35/4.*sph_rad);
 		printf("\nback_text alias back_label_mat vellum\n");
 		printf("\nback_label_mat polygon back_label\n0\n0\n12");
 		printf("\n\t%f %f 0\n\t%f %f 0\n\t%f %f 0\n\t%f %f 0\n",
-				-.25*sph_rad + sph_xoffset, -1.1*sph_rad,
-				-.25*sph_rad + sph_xoffset, (-1.2-1.6*.35/4.-.1)*sph_rad,
-				.25*sph_rad + sph_xoffset, (-1.2-1.6*.35/4.-.1)*sph_rad,
-				.25*sph_rad + sph_xoffset, -1.1*sph_rad );
+				-.25*sph_rad - sph_xoffset, -1.3*sph_rad,
+				-.25*sph_rad - sph_xoffset, (-1.4-1.6*.35/4.-.1)*sph_rad,
+				.25*sph_rad - sph_xoffset, (-1.4-1.6*.35/4.-.1)*sph_rad,
+				.25*sph_rad - sph_xoffset, -1.3*sph_rad );
 	}
 }
 
@@ -579,24 +552,24 @@ static void
 put_scale(void)
 {
 	const double	max_log10 = log10(overall_max);
-	const double	leg_width = 2.*.75*(sph_xoffset - sph_rad);
+	const double	leg_width = 2.*.75*(fabs(sph_xoffset) - sph_rad);
 	const double	leg_height = 2.*sph_rad;
 	const int	text_lines = 6;
-	const int	text_digits = 7;
+	const int	text_digits = 8;
 	char		fmt[16];
 	int		i;
 
 	printf("\n# BSDF legend with falsecolor scale\n");
 	printf("\nvoid colorfunc lscale\n10 sca_red(Py) sca_grn(Py) sca_blu(Py)");
 	printf("\n\tbsdf2rad.cal -s %f -t 0 %f 0\n0\n0\n", leg_height, -.5*leg_height);
-	sprintf(fmt, "%%%dg", text_digits-2);
+	sprintf(fmt, "%%.%df", text_digits-3);
 	for (i = 0; i < text_lines; i++) {
 		char	vbuf[16];
 		sprintf(vbuf, fmt, pow(10., (i+.5)/text_lines*(max_log10-min_log10)+min_log10));
 		printf("\nlscale brighttext lscale\n");
 		printf("3 helvet.fnt . %s\n0\n12\n", vbuf);
 		printf("\t%f %f 0\n", -.45*leg_width, ((i+.9)/text_lines-.5)*leg_height);
-		printf("\t%f 0 0\n", .9*leg_width/strlen(vbuf));
+		printf("\t%f 0 0\n", .8*leg_width/strlen(vbuf));
 		printf("\t0 %f 0\n", -.9/text_lines*leg_height);
 		printf("\t.01 1 -.1\n");
 	}
@@ -623,7 +596,7 @@ put_scale(void)
 		return;
 	printf("\nvoid brighttext BSDFname\n3 helvet.fnt . \"%s\"\n0\n12\n", bsdf_name);
 	printf("\t%f %f 0\n", -.95*leg_width, -.6*leg_height);
-	printf("\t%f 0 0\n", .4/strlen(bsdf_name)*leg_width);
+	printf("\t%f 0 0\n", 1.8/strlen(bsdf_name)*leg_width);
 	printf("\t0 %f 0\n", -.1*leg_height);
 	printf("\t.01 1 -.1\n");
 	printf("\nBSDFname alias name_mat vellum\n");
@@ -678,7 +651,7 @@ convert_mgf(const char *mgfdata)
 		sprintf(cmdbuf, "xform -t %f %f %f -s %f -t %f %f 0 %s",
 				-.5*(xmin+xmax), -.5*(ymin+ymax), -zmax,
 				1.5*sph_rad/max_dim,
-				-sph_xoffset, -2.5*sph_rad,
+				sph_xoffset, -2.5*sph_rad,
 				radfn);
 		if (!run_cmd(cmdbuf))
 			return;
@@ -688,7 +661,7 @@ convert_mgf(const char *mgfdata)
 		sprintf(cmdbuf, "xform -t %f %f %f -s %f -ry 180 -t %f %f 0 %s",
 				-.5*(xmin+xmax), -.5*(ymin+ymax), -zmin,
 				1.5*sph_rad/max_dim,
-				sph_xoffset, -2.5*sph_rad,
+				-sph_xoffset, -2.5*sph_rad,
 				radfn);
 		if (!run_cmd(cmdbuf))
 			return;
@@ -699,7 +672,7 @@ convert_mgf(const char *mgfdata)
 static int
 rbf_headline(char *s, void *p)
 {
-	char	fmt[64];
+	char	fmt[MAXFMTLEN];
 
 	if (formatval(fmt, s)) {
 		if (strcmp(fmt, BSDFREP_FMT))
@@ -733,27 +706,35 @@ int
 main(int argc, char *argv[])
 {
 	int	inpXML = -1;
+	double	myLim[2];
 	SDData	myBSDF;
-	int	n;
+	int	a, n;
 						/* check arguments */
 	progname = argv[0];
-	if (argc > 1 && (n = strlen(argv[1])-4) > 0) {
-		if (!strcasecmp(argv[1]+n, ".xml"))
+	a = 1;
+	myLim[0] = -1; myLim[1] = -2;		/* specified BSDF range? */
+	if (argc > a+3 && argv[a][0] == '-' && argv[a][1] == 'r') {
+		myLim[0] = atof(argv[++a]);
+		myLim[1] = atof(argv[++a]);
+		++a;
+	}
+	if (argc > a && (n = strlen(argv[a])-4) > 0) {
+		if (!strcasecmp(argv[a]+n, ".xml"))
 			inpXML = 1;
-		else if (!strcasecmp(argv[1]+n, ".sir"))
+		else if (!strcasecmp(argv[a]+n, ".sir"))
 			inpXML = 0;
 	}
-	if (inpXML < 0 || inpXML & (argc > 2)) {
-		fprintf(stderr, "Usage: %s bsdf.xml > output.rad\n", progname);
-		fprintf(stderr, "   Or: %s hemi1.sir hemi2.sir .. > output.rad\n", progname);
+	if (inpXML < 0 || inpXML & (argc > a+1)) {
+		fprintf(stderr, "Usage: %s [-r min max] bsdf.xml > output.rad\n", progname);
+		fprintf(stderr, "   Or: %s [-r min max] hemi1.sir hemi2.sir .. > output.rad\n", progname);
 		return(1);
 	}
 	fputs("# ", stdout);			/* copy our command */
 	printargs(argc, argv, stdout);
 						/* evaluate BSDF */
 	if (inpXML) {
-		SDclearBSDF(&myBSDF, argv[1]);
-		if (SDreportError(SDloadFile(&myBSDF, argv[1]), stderr))
+		SDclearBSDF(&myBSDF, argv[a]);
+		if (SDreportError(SDloadFile(&myBSDF, argv[a]), stderr))
 			return(1);
 		if (myBSDF.rf != NULL) front_comp |= SDsampR;
 		if (myBSDF.tf != NULL) front_comp |= SDsampT;
@@ -761,16 +742,21 @@ main(int argc, char *argv[])
 		if (myBSDF.tb != NULL) back_comp |= SDsampT;
 		if (!front_comp & !back_comp) {
 			fprintf(stderr, "%s: nothing to plot in '%s'\n",
-					progname, argv[1]);
+					progname, argv[a]);
 			return(1);
 		}
-		if (front_comp & SDsampR && myBSDF.rLambFront.cieY < overall_min*PI)
-			overall_min = myBSDF.rLambFront.cieY/PI;
-		if (back_comp & SDsampR && myBSDF.rLambBack.cieY < overall_min*PI)
-			overall_min = myBSDF.rLambBack.cieY/PI;
-		if ((front_comp|back_comp) & SDsampT &&
-				myBSDF.tLamb.cieY < overall_min*PI)
-			overall_min = myBSDF.tLamb.cieY/PI;
+		if (myLim[0] >= 0)
+			overall_min = myLim[0];
+		else {
+			if (front_comp & SDsampR && myBSDF.rLambFront.cieY < overall_min*PI)
+				overall_min = myBSDF.rLambFront.cieY/PI;
+			if (back_comp & SDsampR && myBSDF.rLambBack.cieY < overall_min*PI)
+				overall_min = myBSDF.rLambBack.cieY/PI;
+			if (front_comp & SDsampT && myBSDF.tLambFront.cieY < overall_min*PI)
+				overall_min = myBSDF.tLambFront.cieY/PI;
+			if (back_comp & SDsampT && myBSDF.tLambBack.cieY < overall_min*PI)
+				overall_min = myBSDF.tLambBack.cieY/PI;
+		}
 		set_minlog();
 		if (!build_wBSDF(&myBSDF))
 			return(1);
@@ -779,40 +765,51 @@ main(int argc, char *argv[])
 		else
 			strcpy(bsdf_name, myBSDF.name);
 		strcpy(bsdf_manuf, myBSDF.makr);
-		put_matBSDF(argv[1]);
+		put_matBSDF(argv[a]);
 	} else {
-		FILE	*fp;
-		for (n = 1; n < argc; n++) {
-			fp = fopen(argv[n], "rb");
-			if (fp == NULL) {
+		FILE	*fp[4];
+		if (argc > a+4) {
+			fprintf(stderr, "%s: more than 4 hemispheres!\n", progname);
+			return(1);
+		}
+		for (n = a; n < argc; n++) {
+			fp[n-a] = fopen(argv[n], "rb");
+			if (fp[n-a] == NULL) {
 				fprintf(stderr, "%s: cannot open BSDF interpolant '%s'\n",
 						progname, argv[n]);
 				return(1);
 			}
-			if (getheader(fp, rbf_headline, NULL) < 0) {
+			if (getheader(fp[n-a], rbf_headline, NULL) < 0) {
 				fprintf(stderr, "%s: bad BSDF interpolant '%s'\n",
 						progname, argv[n]);
 				return(1);
 			}
-			fclose(fp);
 		}
+		if (myLim[0] >= 0)
+			overall_min = myLim[0];
 		set_minlog();
-		for (n = 1; n < argc; n++) {
-			fp = fopen(argv[n], "rb");
-			if (!load_bsdf_rep(fp))
+		for (n = a; n < argc; n++) {
+			if (fseek(fp[n-a], 0L, SEEK_SET) < 0) {
+				fprintf(stderr, "%s: cannot seek on '%s'\n",
+						progname, argv[n]);
 				return(1);
-			fclose(fp);
+			}
+			if (!load_bsdf_rep(fp[n-a]))
+				return(1);
+			fclose(fp[n-a]);
 			if (!build_wRBF())
 				return(1);
 		}
 		put_matBSDF(NULL);
 	}
+	if (myLim[1] > myLim[0])	/* override maximum BSDF? */
+		overall_max = myLim[1];
 	put_source();			/* before hemispheres & labels */
 	put_hemispheres();
 	put_scale();
 	if (inpXML && myBSDF.mgf)
 		convert_mgf(myBSDF.mgf);
-	if (!put_BSDFs())
+	if (!put_BSDFs())		/* most of the output happens here */
 		return(1);
 	cleanup_tmp();
 	return(0);