--- ray/src/util/glarendx.c	1992/11/19 09:59:08	2.3
+++ ray/src/util/glarendx.c	2020/02/17 19:35:24	2.15
@@ -1,12 +1,13 @@
-/* Copyright (c) 1991 Regents of the University of California */
-
 #ifndef lint
-static char SCCSid[] = "$SunId$ LBL";
+static const char	RCSid[] = "$Id: glarendx.c,v 2.15 2020/02/17 19:35:24 greg Exp $";
 #endif
-
 /*
  * Compute Glare Index given by program name or -t option:
  *
+ *	dgi -		Daylight Glare Index
+ *	brs_gi -	Building Research Station Glare Index (Petherbridge
+ *							       & Hopkinson)
+ *	ugr -		Unified Glare Rating System (Fischer)
  *	guth_dgr -	Guth discomfort glare rating
  *	guth_vcp -	Guth visual comfort probability
  *	cie_cgi -	CIE Glare Index (1983, due to Einhorn)
@@ -15,23 +16,55 @@ static char SCCSid[] = "$SunId$ LBL";
  *	vert_ill -	Total vertical illuminance
  *
  *		12 April 1991	Greg Ward	EPFL
+ *		19 April 1993   R. Compagnon    EPFL (added dgi, brs_gi, ugr)
  */
 
+#include <string.h>
+
 #include "standard.h"
 #include "view.h"
 
-extern double	erfc();
 
-double	posindex();
+struct glare_src {
+	FVECT	dir;		/* source direction */
+	double	dom;		/* solid angle */
+	double	lum;		/* average luminance */
+	struct glare_src	*next;
+} *all_srcs = NULL;
 
-double	direct(), guth_dgr(), guth_vcp(), cie_cgi(),
-	indirect(), total();
+struct glare_dir {
+	double	ang;		/* angle (in radians) */
+	double	indirect;	/* indirect illuminance */
+	struct glare_dir	*next;
+} *all_dirs = NULL;
 
+typedef double gdfun(struct glare_dir *gd);
+
+static gdfun dgi;
+static gdfun brs_gi;
+static gdfun ugr;
+static gdfun guth_dgr;
+static gdfun guth_vcp;
+static gdfun cie_cgi;
+static gdfun direct;
+static gdfun indirect;
+static gdfun total;
+
+static gethfunc headline;
+static void init(void);
+static void read_input(void);
+static void print_values(gdfun *func);
+static double posindex(FVECT sd, FVECT vd, FVECT vu);
+
+
 struct named_func {
 	char	*name;
-	double	(*func)();
+	gdfun	*func;
 	char	*descrip;
 } all_funcs[] = {
+	{"dgi", dgi, "Daylight Glare Index"},
+	{"brs_gi", brs_gi, "BRS Glare Index"},
+	{"ugr", ugr, "Unified Glare Rating"},
 	{"guth_vcp", guth_vcp, "Guth Visual Comfort Probability"},
 	{"cie_cgi", cie_cgi, "CIE Glare Index (Einhorn)"},
 	{"guth_dgr", guth_dgr, "Guth Disability Glare Rating"},
@@ -41,19 +74,6 @@ struct named_func {
 	{NULL}
 };
 
-struct glare_src {
-	FVECT	dir;		/* source direction */
-	double	dom;		/* solid angle */
-	double	lum;		/* average luminance */
-	struct glare_src	*next;
-} *all_srcs = NULL;
-
-struct glare_dir {
-	double	ang;		/* angle (in radians) */
-	double	indirect;	/* indirect illuminance */
-	struct glare_dir	*next;
-} *all_dirs = NULL;
-
 #define newp(type)	(type *)malloc(sizeof(type))
 
 char	*progname;
@@ -64,17 +84,18 @@ VIEW	midview = STDVIEW;
 int	wrongformat = 0;
 
 
-main(argc, argv)
-int	argc;
-char	*argv[];
+int
+main(
+	int	argc,
+	char	*argv[]
+)
 {
-	extern char	*rindex();
 	struct named_func	*funp;
 	char	*progtail;
 	int	i;
 					/* get program name */
 	progname = argv[0];
-	progtail = rindex(progname, '/');	/* final component */
+	progtail = strrchr(progname, '/');	/* final component */
 	if (progtail == NULL)
 		progtail = progname;
 	else
@@ -120,10 +141,13 @@ userr:
 }
 
 
-headline(s)			/* get line from header */
-char	*s;
+static int
+headline(			/* get line from header */
+	char	*s,
+	void	*p
+)
 {
-	char	fmt[32];
+	char	fmt[MAXFMTLEN];
 
 	if (print_header)		/* copy to output */
 		fputs(s, stdout);
@@ -133,11 +157,14 @@ char	*s;
 		formatval(fmt, s);
 		wrongformat = strcmp(fmt, "ascii");
 	}
+	return(0);
 }
 
 
-init()				/* initialize calculation */
+static void
+init(void)				/* initialize calculation */
 {
+	char	*err;
 					/* read header */
 	getheader(stdin, headline, NULL);
 	if (wrongformat) {
@@ -145,23 +172,30 @@ init()				/* initialize calculation */
 		exit(1);
 	}
 					/* set view */
-	if (setview(&midview) != NULL) {
-		fprintf(stderr, "%s: bad view information in input\n",
+	if ((err = setview(&midview)) != NULL) {
+		fprintf(stderr, "%s: %s\n",
+				progname, err);
+		exit(1);
+	}
+	if (fabs(DOT(midview.vdir, midview.vup)) > 1e-4) {
+		fprintf(stderr,
+		"%s: Input view direction not perpendicular to up vector\n",
 				progname);
 		exit(1);
 	}
 }
 
 
-read_input()			/* read glare sources from stdin */
+static void
+read_input(void)			/* read glare sources from stdin */
 {
 #define	S_SEARCH	0
 #define S_SOURCE	1
 #define S_DIREC		2
 	int	state = S_SEARCH;
 	char	buf[128];
-	register struct glare_src	*gs;
-	register struct glare_dir	*gd;
+	struct glare_src	*gs;
+	struct glare_dir	*gd;
 
 	while (fgets(buf, sizeof(buf), stdin) != NULL)
 		switch (state) {
@@ -178,9 +212,10 @@ read_input()			/* read glare sources from stdin */
 			}
 			if ((gs = newp(struct glare_src)) == NULL)
 				goto memerr;
-			if (sscanf(buf, "%lf %lf %lf %lf %lf",
-					&gs->dir[0], &gs->dir[1], &gs->dir[2],
-					&gs->dom, &gs->lum) != 5)
+			if (sscanf(buf, FVFORMAT, &gs->dir[0], &gs->dir[1],
+						&gs->dir[2]) != 3 ||
+					sscanf(sskip2(buf, 3), "%lf %lf",
+						&gs->dom, &gs->lum) != 2)
 				goto readerr;
 			normalize(gs->dir);
 			gs->next = all_srcs;
@@ -214,23 +249,26 @@ readerr:
 }
 
 
-print_values(funp)		/* print out calculations */
-double	(*funp)();
+static void
+print_values(		/* print out calculations */
+	gdfun *func
+)
 {
-	register struct glare_dir	*gd;
+	struct glare_dir	*gd;
 
 	for (gd = all_dirs; gd != NULL; gd = gd->next)
-		printf("%f\t%f\n", gd->ang*(180.0/PI), (*funp)(gd));
+		printf("%f\t%f\n", gd->ang*(180.0/PI), (*func)(gd));
 }
 
 
-double
-direct(gd)			/* compute direct vertical illuminance */
-struct glare_dir	*gd;
+static double
+direct(			/* compute direct vertical illuminance */
+	struct glare_dir	*gd
+)
 {
 	FVECT	mydir;
 	double	d, dval;
-	register struct glare_src	*gs;
+	struct glare_src	*gs;
 
 	spinvector(mydir, midview.vdir, midview.vup, gd->ang);
 	dval = 0.0;
@@ -243,17 +281,19 @@ struct glare_dir	*gd;
 }
 
 
-double
-indirect(gd)			/* return indirect vertical illuminance */
-struct glare_dir	*gd;
+static double
+indirect(			/* return indirect vertical illuminance */
+	struct glare_dir	*gd
+)
 {
 	return(gd->indirect);
 }
 
 
-double
-total(gd)			/* return total vertical illuminance */
-struct glare_dir	*gd;
+static double
+total(			/* return total vertical illuminance */
+	struct glare_dir	*gd
+)
 {
 	return(direct(gd)+gd->indirect);
 }
@@ -273,9 +313,12 @@ struct glare_dir	*gd;
  * We return a value less than zero for improper positions.
  */
 
-double
-posindex(sd, vd, vu)			/* compute position index */
-FVECT	sd, vd, vu;
+static double
+posindex(			/* compute position index */
+	FVECT	sd,
+	FVECT	vd,
+	FVECT	vu
+)
 {
 	double	sigma, tau;
 	double	d;
@@ -283,28 +326,102 @@ FVECT	sd, vd, vu;
 	d = DOT(sd,vd);
 	if (d <= 0.0)
 		return(-1.0);
-	if (d >= 1.0)
+	if (d >= 1.0-FTINY)
 		return(1.0);
 	sigma = acos(d) * (180./PI);
-	d = DOT(sd,vu)/sqrt(1.0-d*d);
-	if (d >= 1.0)
-		tau = 0.0;
-	else if (d <= -1.0)
-		tau = 180.0;
-	else
-		tau = acos(d) * (180./PI);
+	d = fabs(DOT(sd,vu)/sqrt(1.0-d*d));
+	tau = Acos(d) * (180./PI);
 	return( exp( sigma*( (35.2 - tau*.31889 - 1.22*exp(-.22222*tau))*1e-3
 			+ sigma*(21. + tau*(.26667 + tau*-.002963))*1e-5 )
 		) );
 }
 
 
-double
-guth_dgr(gd)		/* compute Guth discomfort glare rating */
-struct glare_dir	*gd;
+static double
+dgi(		/* compute Daylight Glare Index */
+	struct glare_dir	*gd
+)
 {
+	struct glare_src	*gs;
+	FVECT	mydir,testdir[7],vhor;
+	double	r,posn,omega,p[7],sum;
+	int	i;
+
+	spinvector(mydir, midview.vdir, midview.vup, gd->ang);
+	sum = 0.0;
+	for (gs = all_srcs; gs != NULL; gs = gs->next) {
+
+		/* compute 1/p^2 weighted solid angle of the source */
+		r = 1. - gs->dom*(.5/PI);
+		r = sqrt(1. - r*r);
+		fcross(vhor,gs->dir,midview.vup);
+		if (normalize(vhor) == 0.)
+			continue;
+		VCOPY(testdir[0],gs->dir);
+		fvsum(testdir[1],gs->dir,vhor,r);
+		fvsum(testdir[2],gs->dir,vhor,0.5*r);
+		fvsum(testdir[5],testdir[2],midview.vup,-0.866*r);
+		fvsum(testdir[2],testdir[2],midview.vup,0.866*r);
+		fvsum(testdir[3],gs->dir,vhor,-r);
+		fvsum(testdir[4],gs->dir,vhor,-0.5*r);
+		fvsum(testdir[6],testdir[4],midview.vup,0.866*r);
+		fvsum(testdir[4],testdir[4],midview.vup,-0.866*r);
+		for (i = 0; i < 7; i++) {
+			p[i] = 0.0;
+			if (normalize(testdir[i]) == 0.)
+				continue;
+			posn = posindex(testdir[i],mydir,midview.vup);
+			if (posn > FTINY)
+				p[i] = 1./(posn*posn);
+		}
+		r = 1. - gs->dom*(.5/PI);
+		omega = gs->dom*p[0];
+		omega += (r*PI*(1.+1./(r*r))-2.*PI)*(-p[0]+(p[1]+p[2])*0.5);
+		omega += (2.*PI-r*PI*(1.+1./(r*r)))*(-p[0]-0.1667*(p[1]+p[3])
+			  +0.3334*(p[2]+p[4]+p[5]+p[6]));
+		if (omega <= 0.)
+			continue;
+		sum += pow(gs->lum,1.6) * pow(omega,0.8) /
+		       (gd->indirect*(1./PI) + 0.07*sqrt(gs->dom)*gs->lum);
+	}
+	if (sum <= FTINY)
+		return(0.0);
+	return( 10.*log10(0.478*sum) );
+}
+
+
+static double
+brs_gi(		/* compute BRS Glare Index */
+	struct glare_dir	*gd
+)
+{
+	struct glare_src	*gs;
+	FVECT	mydir;
+	double	p;
+	double	sum;
+
+	spinvector(mydir, midview.vdir, midview.vup, gd->ang);
+	sum = 0.0;
+	for (gs = all_srcs; gs != NULL; gs = gs->next) {
+		p = posindex(gs->dir, mydir, midview.vup);
+		if (p <= FTINY)
+			continue;
+		sum += pow(gs->lum/p,1.6) * pow(gs->dom,0.8);
+	}
+	if (sum <= FTINY)
+		return(0.0);
+	sum *= PI/gd->indirect;
+	return(10*log10(0.478*sum));
+}
+
+
+static double
+guth_dgr(		/* compute Guth discomfort glare rating */
+	struct glare_dir	*gd
+)
+{
 #define q(w)	(20.4*w+1.52*pow(w,.2)-.075)
-	register struct glare_src	*gs;
+	struct glare_src	*gs;
 	FVECT	mydir;
 	double	p;
 	double	sum;
@@ -324,15 +441,12 @@ struct glare_dir	*gd;
 	}
 	if (n == 0)
 		return(0.0);
-
 	return( pow(.5*sum/pow((brsum+(5.-wtot)*gd->indirect/PI)/5.,.44),
 			pow((double)n, -.0914) ) );
 #undef q
 }
 
 
-extern double	erf(), erfc();
-
 #ifndef M_SQRT2
 #define	M_SQRT2	1.41421356237309504880
 #endif
@@ -340,10 +454,12 @@ extern double	erf(), erfc();
 #define norm_integral(z)	(1.-.5*erfc((z)/M_SQRT2))
 
 
-double
-guth_vcp(gd)		/* compute Guth visual comfort probability */
-struct glare_dir	*gd;
+static double
+guth_vcp(		/* compute Guth visual comfort probability */
+	struct glare_dir	*gd
+)
 {
+	extern double	erfc();
 	double	dgr;
 
 	dgr = guth_dgr(gd);
@@ -353,11 +469,12 @@ struct glare_dir	*gd;
 }
 
 
-double
-cie_cgi(gd)		/* compute CIE Glare Index */
-struct glare_dir	*gd;
+static double
+cie_cgi(		/* compute CIE Glare Index */
+	struct glare_dir	*gd
+)
 {
-	register struct glare_src	*gs;
+	struct glare_src	*gs;
 	FVECT	mydir;
 	double	dillum;
 	double	p;
@@ -375,4 +492,28 @@ struct glare_dir	*gd;
 		return(0.0);
 	dillum = direct(gd);
 	return(8.*log10(2.*sum*(1.+dillum/500.)/(dillum+gd->indirect)));
+}
+
+
+static double
+ugr(		/* compute Unified Glare Rating */
+	struct glare_dir	*gd
+)
+{
+	struct glare_src	*gs;
+	FVECT	mydir;
+	double	p;
+	double	sum;
+
+	spinvector(mydir, midview.vdir, midview.vup, gd->ang);
+	sum = 0.0;
+	for (gs = all_srcs; gs != NULL; gs = gs->next) {
+		p = posindex(gs->dir, mydir, midview.vup);
+		if (p <= FTINY)
+			continue;
+		sum += gs->lum*gs->lum * gs->dom / (p*p);
+	}
+	if (sum <= FTINY)
+		return(0.0);
+	return(8.*log10(0.25*sum*PI/gd->indirect));
 }