--- ray/src/gen/gensky.c	1992/03/20 12:23:38	2.4
+++ ray/src/gen/gensky.c	1992/10/23 14:19:35	2.8
@@ -36,7 +36,8 @@ extern double  s_longitude;
 extern double  s_meridian;
 					/* required values */
 int  month, day;				/* date */
-double  hour;					/* standard time */
+double  hour;					/* time */
+int  tsolar;					/* 0=standard, 1=solar */
 double  altitude, azimuth;			/* or solar angles */
 					/* default values */
 int  cloudy = 0;				/* 1=standard, 2=uniform */
@@ -48,7 +49,7 @@ double  gprefl = 0.2;
 double  sundir[3];
 double  groundbr;
 double  F2;
-double  solarbr;
+double  solarbr = -1.0;
 
 char  *progname;
 char  errmsg[128];
@@ -58,7 +59,6 @@ main(argc, argv)
 int  argc;
 char  *argv[];
 {
-	extern double  fabs();
 	int  i;
 
 	progname = argv[0];
@@ -74,8 +74,15 @@ char  *argv[];
 		month = 0;
 	} else {
 		month = atoi(argv[1]);
+		if (month < 1 || month > 12)
+			userror("bad month");
 		day = atoi(argv[2]);
+		if (day < 1 || day > 31)
+			userror("bad day");
 		hour = atof(argv[3]);
+		if (hour < 0 || hour >= 24)
+			userror("bad hour");
+		tsolar = argv[3][0] == '+';
 	}
 	for (i = 4; i < argc; i++)
 		if (argv[i][0] == '-' || argv[i][0] == '+')
@@ -84,6 +91,9 @@ char  *argv[];
 				cloudy = 0;
 				dosun = argv[i][0] == '+';
 				break;
+			case 'r':
+				solarbr = atof(argv[++i]);
+				break;
 			case 'c':
 				cloudy = argv[i][0] == '+' ? 2 : 1;
 				dosun = 0;
@@ -134,7 +144,10 @@ computesky()			/* compute sky parameters */
 
 		jd = jdate(month, day);		/* Julian date */
 		sd = sdec(jd);			/* solar declination */
-		st = hour + stadj(jd);		/* solar time */
+		if (tsolar)			/* solar time */
+			st = hour;
+		else
+			st = hour + stadj(jd);
 		altitude = salt(sd, st);
 		azimuth = sazi(sd, st);
 	}
@@ -146,7 +159,7 @@ computesky()			/* compute sky parameters */
 	if (zenithbr <= 0.0)
 		if (cloudy) {
 			zenithbr = 8.6*sundir[2] + .123;
-			zenithbr *= 1000.0/SKYEFFICACY;
+			zenithbr *= 1000.0/WHTEFFICACY;
 		} else {
 			zenithbr = (1.376*turbidity-1.81)*tan(altitude)+0.38;
 			zenithbr *= 1000.0/SKYEFFICACY;
@@ -163,14 +176,12 @@ computesky()			/* compute sky parameters */
 	} else {
 		F2 = 0.274*(0.91 + 10.0*exp(-3.0*(PI/2.0-altitude)) +
 				0.45*sundir[2]*sundir[2]);
-		groundbr = zenithbr*normsc(PI/2.0-altitude)/F2/PI;
+		groundbr = zenithbr*normsc(altitude)/F2/PI;
 		printf("# Ground ambient level: %f\n", groundbr);
-		if (sundir[2] > 0.0) {
-			if (sundir[2] > .16)
-				solarbr = (1.5e9/SUNEFFICACY) *
-					(1.147 - .147/sundir[2]);
-			else
-				solarbr = 1.5e9/SUNEFFICACY*(1.147-.147/.16);
+		if (sundir[2] > 0.0 && solarbr != 0.0) {
+			if (solarbr < 0.0)
+				solarbr = 1.5e9/SUNEFFICACY *
+				(1.147 - .147/(sundir[2]>.16?sundir[2]:.16));
 			groundbr += solarbr*6e-5*sundir[2]/PI;
 		} else
 			dosun = 0;