--- ray/src/hd/rhdisp3.c	1997/11/24 15:17:41	3.5
+++ ray/src/hd/rhdisp3.c	1997/11/26 20:12:19	3.7
@@ -271,3 +271,54 @@ VIEW	*vp;
 memerr:
 	error(SYSTEM, "out of memory in getviewcells");
 }
+
+
+gridlines(f)			/* run through holodeck section grid lines */
+int	(*f)();
+{
+	register int	hd, w, i;
+	int	g0, g1;
+	FVECT	wp[2], mov;
+	double	d;
+					/* do each wall on each section */
+	for (hd = 0; hdlist[hd] != NULL; hd++)
+		for (w = 0; w < 6; w++) {
+			g0 = ((w>>1)+1)%3;
+			g1 = ((w>>1)+2)%3;
+			d = 1.0/hdlist[hd]->grid[g0];
+			mov[0] = d * hdlist[hd]->xv[g0][0];
+			mov[1] = d * hdlist[hd]->xv[g0][1];
+			mov[2] = d * hdlist[hd]->xv[g0][2];
+			if (w & 1) {
+				VSUM(wp[0], hdlist[hd]->orig,
+						hdlist[hd]->xv[w>>1], 1.);
+				VSUM(wp[0], wp[0], mov, 1.);
+			} else
+				VCOPY(wp[0], hdlist[hd]->orig);
+			VSUM(wp[1], wp[0], hdlist[hd]->xv[g1], 1.);
+			for (i = hdlist[hd]->grid[g0]; ; ) {	/* g0 lines */
+				(*f)(wp);
+				if (!--i) break;
+				wp[0][0] += mov[0]; wp[0][1] += mov[1];
+				wp[0][2] += mov[2]; wp[1][0] += mov[0];
+				wp[1][1] += mov[1]; wp[1][2] += mov[2];
+			}
+			d = 1.0/hdlist[hd]->grid[g1];
+			mov[0] = d * hdlist[hd]->xv[g1][0];
+			mov[1] = d * hdlist[hd]->xv[g1][1];
+			mov[2] = d * hdlist[hd]->xv[g1][2];
+			if (w & 1)
+				VSUM(wp[0], hdlist[hd]->orig,
+						hdlist[hd]->xv[w>>1], 1.);
+			else
+				VSUM(wp[0], hdlist[hd]->orig, mov, 1.);
+			VSUM(wp[1], wp[0], hdlist[hd]->xv[g0], 1.);
+			for (i = hdlist[hd]->grid[g1]; ; ) {	/* g1 lines */
+				(*f)(wp);
+				if (!--i) break;
+				wp[0][0] += mov[0]; wp[0][1] += mov[1];
+				wp[0][2] += mov[2]; wp[1][0] += mov[0];
+				wp[1][1] += mov[1]; wp[1][2] += mov[2];
+			}
+		}
+}