--- ray/src/px/panim.c	1990/04/05 13:58:45	1.6
+++ ray/src/px/panim.c	2003/06/30 14:59:12	2.3
@@ -1,9 +1,6 @@
-/* Copyright (c) 1988 Regents of the University of California */
-
 #ifndef lint
-static char SCCSid[] = "$SunId$ LBL";
+static const char	RCSid[] = "$Id: panim.c,v 2.3 2003/06/30 14:59:12 schorsch Exp $";
 #endif
-
 /*
  *  Send pictures to PC animation system.
  *
@@ -11,6 +8,7 @@ static char SCCSid[] = "$SunId$ LBL";
  */
 
 #include <stdio.h>
+#include <string.h>
 
 #include "random.h"
 #include "color.h"
@@ -103,6 +101,11 @@ char	*file;
 	}
 						/* get dimensions */
 	getheader(fp, NULL);
+	if (checkheader(fp, COLRFMT, NULL) < 0) {
+		fputs(file, stderr);
+		fputs(": not a Radiance picture\n", stderr);
+		exit(1);
+	}
 	if (fgetresolu(&xres, &yres, fp) != (YMAJOR|YDECR) ||
 			xres > SCANLINE || yres > NUMSCANS) {
 		fputs(file, stderr);
@@ -113,7 +116,7 @@ char	*file;
 	xbeg = (SCANLINE-xres)/2;
 	ybeg = (NUMSCANS-yres)/2;
 						/* clear output */
-	bzero(sc_frame_arr, sizeof(sc_frame_arr));
+	memset(sc_frame_arr, '\0', sizeof(sc_frame_arr));
 						/* get frame */
 	for (y = yres-1; y >= 0; y--) {
 		if (freadcolrs(scanin, xres, fp) < 0) {
@@ -144,7 +147,7 @@ compgamma()				/* compute gamma correction map */
 	register int  i, val;
 
 	for (i = 0; i < 256; i++) {
-		val = pow(i/256.0, 1.0/GAMMA) * 256.0;
+		val = pow((i+0.5)/256.0, 1.0/GAMMA) * 256.0;
 		if (val > 248) val = 248;
 		gammamap[i] = val;
 	}