--- ray/src/common/image.c	1990/10/15 14:17:05	1.13
+++ ray/src/common/image.c	1991/04/18 14:52:55	1.15
@@ -27,10 +27,13 @@ register VIEW  *v;
 	if (normalize(v->vdir) == 0.0)		/* normalize direction */
 		return("zero view direction");
 
+	if (normalize(v->vup) == 0.0)		/* normalize view up */
+		return("zero view up vector");
+
 	fcross(v->hvec, v->vdir, v->vup);	/* compute horiz dir */
 
 	if (normalize(v->hvec) == 0.0)
-		return("illegal view up vector");
+		return("view up parallel to view direction");
 
 	fcross(v->vvec, v->hvec, v->vdir);	/* compute vert dir */
 
@@ -329,21 +332,25 @@ FILE  *fp;
 }
 
 
-static VIEW  *hview;			/* view from header */
-static int  gothview;			/* success indicator */
 static char  *altname[] = {NULL,"rpict","rview","pinterp",VIEWSTR,NULL};
 
+struct myview {
+	VIEW	*hv;
+	int	ok;
+};
 
+
 static
-gethview(s)				/* get view from header */
+gethview(s, v)				/* get view from header */
 char  *s;
+register struct myview  *v;
 {
 	register char  **an;
 
 	for (an = altname; *an != NULL; an++)
 		if (!strncmp(*an, s, strlen(*an))) {
-			if (sscanview(hview, s+strlen(*an)) > 0)
-				gothview++;
+			if (sscanview(v->hv, s+strlen(*an)) > 0)
+				v->ok++;
 			return;
 		}
 }
@@ -356,22 +363,23 @@ VIEW  *vp;
 int  *xp, *yp;
 {
 	extern char  *progname;
+	struct myview	mvs;
 	FILE  *fp;
 
 	if ((fp = fopen(fname, "r")) == NULL)
 		return(-1);
 
 	altname[0] = progname;
-	hview = vp;
-	gothview = 0;
+	mvs.hv = vp;
+	mvs.ok = 0;
 
-	getheader(fp, gethview);
+	getheader(fp, gethview, &mvs);
 
 	if (xp != NULL && yp != NULL
 			&& fgetresolu(xp, yp, fp) == -1)
-		gothview = 0;
+		mvs.ok = 0;
 
 	fclose(fp);
 
-	return(gothview);
+	return(mvs.ok);
 }