--- ray/src/util/rsensor.c	2013/10/16 04:35:50	2.13
+++ ray/src/util/rsensor.c	2015/04/23 23:54:08	2.16
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: rsensor.c,v 2.13 2013/10/16 04:35:50 greg Exp $";
+static const char RCSid[] = "$Id: rsensor.c,v 2.16 2015/04/23 23:54:08 greg Exp $";
 #endif
 
 /*
@@ -15,7 +15,7 @@ static const char RCSid[] = "$Id: rsensor.c,v 2.13 201
 
 #define DEGREE		(PI/180.)
 
-#define	MAXNT		180	/* maximum number of theta divisions */
+#define	MAXNT		181	/* maximum number of theta divisions */
 #define MAXNP		360	/* maximum number of phi divisions */
 
 extern char	*progname;	/* global argv[0] */
@@ -209,6 +209,7 @@ load_sensor(
 {
 	int	warnedneg;
 	char	linebuf[8192];
+	int	last_pos_val = 0;
 	int	nelem = 1000;
 	float	*sarr = (float *)malloc(sizeof(float)*nelem);
 	FILE	*fp;
@@ -269,7 +270,8 @@ load_sensor(
 					error(WARNING, errmsg);
 				}
 				sarr[i] = .0;
-			}
+			} else if (i > ntp[0]*(ntp[1]+1) && sarr[i] > FTINY)
+				last_pos_val = i;
 			++i;
 		}
 		if (i == ntp[0]*(ntp[1]+1))
@@ -288,9 +290,13 @@ load_sensor(
 			error(USER, errmsg);
 		}
 	}
-	nelem = i;
+						/* truncate zero region */
+	ntp[0] = (last_pos_val + ntp[1])/(ntp[1]+1) - 1;
+	nelem = (ntp[0]+1)*(ntp[1]+1);
 	fclose(fp);
 	errmsg[0] = '\0';			/* sanity checks */
+	if (!last_pos_val)
+		sprintf(errmsg, "no positive sensor values in file '%s'", sfile);
 	if (ntp[0] <= 0)
 		sprintf(errmsg, "no data in sensor file '%s'", sfile);
 	else if (fabs(sarr[ntp[1]+1]) > FTINY)
@@ -305,8 +311,8 @@ load_sensor(
 				sfile);
 	else if (sarr[ntp[0]*(ntp[1]+1)] <= FTINY)
 		sprintf(errmsg,
-			"maximum theta must be positive in sensor file '%s'",
-				sfile);
+			"maximum theta (%f) must be positive in sensor file '%s'",
+				sarr[ntp[0]*(ntp[1]+1)], sfile);
 	if (errmsg[0])
 		error(USER, errmsg);
 	return((float *)realloc((void *)sarr, sizeof(float)*nelem));
@@ -398,9 +404,8 @@ init_ptable(
 		tvals[i] = 1. - ( (1.-frac)*cos(thdiv[t]) +
 						frac*cos(thdiv[t+1]) );
 				/* offset b/c sensor values are centered */
-		if ((t < sntp[0]-1) & (frac >= 0.5)) {
-			if ((frac -= 0.5) < 0)
-				frac = 0;
+		if ((t < sntp[0]-1) & (!t | (frac >= 0.5))) {
+			frac -= 0.5;
 		} else {
 			frac += 0.5;
 			--t;
@@ -425,6 +430,9 @@ init_ptable(
 		}
 		pvals[i*(nphi+1) + nphi] = phdiv[sntp[1]];
 	}
+						/* duplicate final row */
+	memcpy(pvals+ntheta*(nphi+1), pvals+(ntheta-1)*(nphi+1),
+				sizeof(*pvals)*(nphi+1));
 	tvals[0] = .0f;
 	tvals[ntheta] = (float)tsize;
 }