--- ray/src/util/rpiece.c	2004/03/26 21:36:20	2.43
+++ ray/src/util/rpiece.c	2009/02/07 05:40:47	2.50
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char	RCSid[] = "$Id: rpiece.c,v 2.43 2004/03/26 21:36:20 schorsch Exp $";
+static const char	RCSid[] = "$Id: rpiece.c,v 2.50 2009/02/07 05:40:47 greg Exp $";
 #endif
 /*
  * Generate sections of a picture.
@@ -9,11 +9,13 @@ static const char	RCSid[] = "$Id: rpiece.c,v 2.43 2004
 #include <stdio.h>
 #include <signal.h>
 #include <sys/types.h>
-#include <sys/wait.h>
 
 #include "platform.h"
-#include "rtio.h"
-#include "rtmisc.h"
+#ifndef NON_POSIX /* XXX need abstraction for process management */
+ #include <sys/wait.h>
+#endif
+
+#include "standard.h"
 #include "color.h"
 #include "view.h"
 #include "rtprocess.h"
@@ -106,7 +108,7 @@ main(
 		while ((rval = expandarg(&argc, &argv, i)) > 0)
 			;
 		if (rval < 0) {
-			fprintf(stderr, "%s: cannot expand '%s'",
+			fprintf(stderr, "%s: cannot expand '%s'\n",
 					argv[0], argv[i]);
 			exit(1);
 		}
@@ -247,6 +249,10 @@ init(			/* set up output file and start rpict */
 					/* compute piece size */
 	hres /= hmult;
 	vres /= vmult;
+	if (hres <= 0 || vres <= 0) {
+		fprintf(stderr, "%s: illegal resolution/subdivision\n", progname);
+		exit(1);
+	}
 	normaspect(viewaspect(&ourview)*hmult/vmult, &pixaspect, &hres, &vres);
 	sprintf(hrbuf, "%d", hres);
 	rpargv[rpargc++] = "-x"; rpargv[rpargc++] = hrbuf;
@@ -432,10 +438,10 @@ rpiece(void)			/* render picture piece by piece */
 	pview = ourview;
 	switch (ourview.type) {
 	case VT_PER:
-		pview.horiz = 2.*180./PI*atan(
-				tan(PI/180./2.*ourview.horiz)/hmult );
-		pview.vert = 2.*180./PI*atan(
-				tan(PI/180./2.*ourview.vert)/vmult );
+		pview.horiz = (2.*180./PI)*atan(
+				tan((PI/180./2.)*ourview.horiz)/hmult );
+		pview.vert = (2.*180./PI)*atan(
+				tan((PI/180./2.)*ourview.vert)/vmult );
 		break;
 	case VT_PAR:
 	case VT_ANG:
@@ -444,14 +450,26 @@ rpiece(void)			/* render picture piece by piece */
 		break;
 	case VT_CYL:
 		pview.horiz = ourview.horiz / hmult;
-		pview.vert = 2.*180./PI*atan(
-				tan(PI/180./2.*ourview.vert)/vmult );
+		pview.vert = (2.*180./PI)*atan(
+				tan((PI/180./2.)*ourview.vert)/vmult );
 		break;
 	case VT_HEM:
-		pview.horiz = 2.*180./PI*asin(
-				sin(PI/180./2.*ourview.horiz)/hmult );
-		pview.vert = 2.*180./PI*asin(
-				sin(PI/180./2.*ourview.vert)/vmult );
+		pview.horiz = (2.*180./PI)*asin(
+				sin((PI/180./2.)*ourview.horiz)/hmult );
+		pview.vert = (2.*180./PI)*asin(
+				sin((PI/180./2.)*ourview.vert)/vmult );
+		break;
+	case VT_PLS:
+		pview.horiz = sin((PI/180./2.)*ourview.horiz) /
+				(1.0 + cos((PI/180./2.)*ourview.horiz)) / hmult;
+		pview.horiz *= pview.horiz;
+		pview.horiz = (2.*180./PI)*acos((1. - pview.horiz) /
+						(1. + pview.horiz));
+		pview.vert = sin((PI/180./2.)*ourview.vert) /
+				(1.0 + cos((PI/180./2.)*ourview.vert)) / vmult;
+		pview.vert *= pview.vert;
+		pview.vert = (2.*180./PI)*acos((1. - pview.vert) /
+						(1. + pview.vert));
 		break;
 	default:
 		fprintf(stderr, "%s: unknown view type '-vt%c'\n",