--- ray/src/rt/rv2.c	1993/09/09 13:47:55	2.20
+++ ray/src/rt/rv2.c	1995/05/04 15:50:26	2.31
@@ -1,4 +1,4 @@
-/* Copyright (c) 1993 Regents of the University of California */
+/* Copyright (c) 1994 Regents of the University of California */
 
 #ifndef lint
 static char SCCSid[] = "$SunId$ LBL";
@@ -32,6 +32,8 @@ static char SCCSid[] = "$SunId$ LBL";
 
 extern char  *atos();
 
+extern FILE  *popen();
+
 extern char  rifname[128];		/* rad input file name */
 
 extern char  VersionID[];
@@ -138,6 +140,16 @@ char  *s;
 	else {
 		nv.horiz = ourview.horiz; nv.vert = ourview.vert;
 	}
+	sprintf(buf, "fore and aft clipping plane (%.6g %.6g): ",
+			ourview.vfore, ourview.vaft);
+	(*dev->comout)(buf);
+	(*dev->comin)(buf, NULL);
+	if (buf[0] == CTRL('C')) return;
+	if (sscanf(buf, "%lf %lf", &nv.vfore, &nv.vaft) == 2)
+		change++;
+	else {
+		nv.vfore = ourview.vfore; nv.vaft = ourview.vaft;
+	}
 	sprintf(buf, "view shift and lift (%.6g %.6g): ",
 			ourview.hoff, ourview.voff);
 	(*dev->comout)(buf);
@@ -274,8 +286,9 @@ char  *s;
 	nv.type = ourview.type;
 	VCOPY(nv.vp, ourview.vp);
 	VCOPY(nv.vup, ourview.vup);
-	nv.hoff = ourview.hoff; nv.voff = ourview.voff;
 	nv.horiz = ourview.horiz; nv.vert = ourview.vert;
+	nv.vfore = ourview.vfore; nv.vaft = ourview.vaft;
+	nv.hoff = ourview.hoff; nv.voff = ourview.voff;
 	zoomview(&nv, zfact);
 	newview(&nv);
 }
@@ -309,6 +322,7 @@ char  *s;
 	VCOPY(nv.vp, ourview.vp);
 	VCOPY(nv.vup, ourview.vup);
 	nv.hoff = ourview.hoff; nv.voff = ourview.voff;
+	nv.vfore = ourview.vfore; nv.vaft = ourview.vaft;
 	spinvector(nv.vdir, ourview.vdir, ourview.vup, angle*(PI/180.));
 	if (elev != 0.0) {
 		fcross(v1, nv.vdir, ourview.vup);
@@ -348,12 +362,13 @@ char  *s;
 	register PNODE  *p = &ptrunk;
 	int  adapt = 0;
 	double  e = 1.0;
-start:
+
 	for (cp = s; isspace(*cp); cp++)
 		;
 	if (*cp == '@') {
 		adapt++;
-		goto start;
+		while (isspace(*++cp))
+			;
 	}
 	if (*cp == '\0') {		/* normalize to point */
 		if (dev->getcur == NULL)
@@ -487,11 +502,12 @@ register char  *s;
 	extern int  do_irrad;
 	extern double  specjitter;
 	extern double  specthresh;
+	extern int  backvis;
 	char  buf[128];
 	
 	if (s[0] == '\0') {
 		(*dev->comout)(
-		"aa ab ad ar as av b dc di dj ds dt i lr lw ps pt sj st: ");
+		"aa ab ad ar as av b dc dv dj ds dt i lr lw ps pt sj st bv: ");
 		(*dev->comin)(buf, NULL);
 		s = buf;
 	}
@@ -530,8 +546,20 @@ register char  *s;
 			goto badparam;
 		}
 		break;
-	case 'b':			/* black and white */
-		getparam(s+1, "black and white", 'b', &greyscale);
+	case 'b':			/* back faces or black and white */
+		switch (s[1]) {
+		case 'v':			/* back face visibility */
+			getparam(s+2, "back face visibility", 'b', &backvis);
+			break;
+		case '\0':			/* black and white */
+		case ' ':
+		case 'y': case 'Y': case 't': case 'T': case '1': case '+':
+		case 'n': case 'N': case 'f': case 'F': case '0': case '-':
+			getparam(s+1, "black and white", 'b', &greyscale);
+			break;
+		default:
+			goto badparam;
+		}
 		break;
 	case 'i':			/* irradiance */
 		getparam(s+1, "irradiance", 'b', &do_irrad);
@@ -607,6 +635,8 @@ char  *s;
 	int  x, y;
 	RAY  thisray;
 
+	thisray.rmax = 0.0;
+
 	if (!sscanvec(s, thisray.rorg) ||
 			!sscanvec(sskip(sskip(sskip(s))), thisray.rdir)) {
 
@@ -616,8 +646,8 @@ char  *s;
 		if ((*dev->getcur)(&x, &y) == ABORT)
 			return;
 
-		if (viewray(thisray.rorg, thisray.rdir, &ourview,
-				(x+.5)/hresolu, (y+.5)/vresolu) < 0) {
+		if ((thisray.rmax = viewray(thisray.rorg, thisray.rdir,
+			&ourview, (x+.5)/hresolu, (y+.5)/vresolu)) < -FTINY) {
 			error(COMMAND, "not on image");
 			return;
 		}
@@ -634,8 +664,10 @@ char  *s;
 	if (thisray.ro == NULL)
 		(*dev->comout)("ray hit nothing");
 	else {
-		sprintf(buf, "ray hit %s %s \"%s\"",
-				objptr(thisray.ro->omod)->oname,
+		sprintf(buf, "ray hit %s%s %s \"%s\"",
+				thisray.rod < 0.0 ? "back of " : "",
+				thisray.ro->omod == OVOID ? VOIDID :
+					objptr(thisray.ro->omod)->oname,
 				ofun[thisray.ro->otype].funame,
 				thisray.ro->oname);
 		(*dev->comout)(buf);
@@ -643,8 +675,9 @@ char  *s;
 		if (thisray.rot >= FHUGE)
 			(*dev->comout)("at infinity");
 		else {
-			sprintf(buf, "at (%.6g %.6g %.6g)", thisray.rop[0],
-					thisray.rop[1], thisray.rop[2]);
+			sprintf(buf, "at (%.6g %.6g %.6g) (%.6g)",
+					thisray.rop[0], thisray.rop[1],
+					thisray.rop[2], thisray.rt);
 			(*dev->comout)(buf);
 		}
 		(*dev->comin)(buf, NULL);
@@ -689,6 +722,7 @@ char  *s;
 	(*dev->comout)(fname);
 	(*dev->comout)("\"...\n");
 						/* write header */
+	newheader("RADIANCE", fp);
 	fputs(progname, fp);
 	fprintview(&ourview, fp);
 	if (octname != NULL)