--- ray/src/hd/rhd_qtree2r.c	1997/11/25 16:51:41	3.1
+++ ray/src/hd/rhd_qtree2r.c	2004/01/01 11:21:55	3.6
@@ -1,9 +1,6 @@
-/* Copyright (c) 1997 Silicon Graphics, Inc. */
-
 #ifndef lint
-static char SCCSid[] = "$SunId$ SGI";
+static const char	RCSid[] = "$Id: rhd_qtree2r.c,v 3.6 2004/01/01 11:21:55 schorsch Exp $";
 #endif
-
 /*
  * Quadtree display support routines for rectangle output.
  */
@@ -12,11 +9,19 @@ static char SCCSid[] = "$SunId$ SGI";
 #include "rhd_qtree.h"
 
 
-static
-redraw(tp, x0, y0, x1, y1, l)	/* mark portion of a tree for redraw */
-register RTREE	*tp;
-int	x0, y0, x1, y1;
-int	l[2][2];
+static void redraw(RTREE *tp, int x0, int y0, int x1, int y1, int l[2][2]);
+static void update( BYTE ca[3], RTREE *tp, int x0, int y0, int x1, int y1);
+
+
+static void
+redraw(	/* mark portion of a tree for redraw */
+	register RTREE	*tp,
+	int	x0,
+	int	y0,
+	int	x1,
+	int	y1,
+	int	l[2][2]
+)
 {
 	int	quads = CH_ANY;
 	int	mx, my;
@@ -25,14 +30,14 @@ int	l[2][2];
 	mx = (x0 + x1) >> 1;
 	my = (y0 + y1) >> 1;
 					/* see what to do */
-	if (l[0][0] >= mx)
-		quads &= ~(CHF(2)|CHF(0));
+	if (l[0][0] > mx)
+		quads &= ~(CHF(UL)|CHF(DL));
 	else if (l[0][1] < mx)
-		quads &= ~(CHF(3)|CHF(1));
-	if (l[1][0] >= my)
-		quads &= ~(CHF(1)|CHF(0));
+		quads &= ~(CHF(UR)|CHF(DR));
+	if (l[1][0] > my)
+		quads &= ~(CHF(DR)|CHF(DL));
 	else if (l[1][1] < my)
-		quads &= ~(CHF(3)|CHF(2));
+		quads &= ~(CHF(UR)|CHF(UL));
 	tp->flgs |= quads;		/* mark quadrants for update */
 					/* climb the branches */
 	for (i = 0; i < 4; i++)
@@ -42,25 +47,45 @@ int	l[2][2];
 }
 
 
-static
-update(ca, tp, x0, y0, x1, y1)	/* update tree display as needed */
-BYTE	ca[3];		/* returned average color */
-register RTREE	*tp;
-int	x0, y0, x1, y1;
+static void
+update(	/* update tree display as needed */
+	BYTE	ca[3],		/* returned average color */
+	register RTREE	*tp,
+	int	x0,
+	int	y0,
+	int	x1,
+	int	y1
+)
 {
 	int	csm[3], nc;
 	register BYTE	*cp;
 	BYTE	rgb[3];
+	double	dpth2[4], d2;
 	int	gaps = 0;
 	int	mx, my;
 	register int	i;
+					/* compute leaf depths */
+	d2 = FHUGE*FHUGE;
+	for (i = 0; i < 4; i++)
+		if (tp->flgs & LFF(i)) {
+			FVECT	dv;
+			register float	*wp = qtL.wp[tp->k[i].li];
+
+			dv[0] = wp[0] - odev.v.vp[0];
+			dv[1] = wp[1] - odev.v.vp[1];
+			dv[2] = wp[2] - odev.v.vp[2];
+			dpth2[i] = DOT(dv,dv);
+			if (dpth2[i] < d2)
+				d2 = dpth2[i];
+		}
+	d2 *= (1.+qtDepthEps)*(1.+qtDepthEps);
 					/* compute midpoint */
 	mx = (x0 + x1) >> 1;
 	my = (y0 + y1) >> 1;
+					/* draw leaves */
 	csm[0] = csm[1] = csm[2] = nc = 0;
-					/* do leaves first */
 	for (i = 0; i < 4; i++) {
-		if (tp->flgs & LFF(i)) {
+		if (tp->flgs & LFF(i) && dpth2[i] <= d2) {
 			cp = qtL.rgb[tp->k[i].li];
 			csm[0] += cp[0]; csm[1] += cp[1]; csm[2] += cp[2];
 			nc++;
@@ -70,7 +95,7 @@ int	x0, y0, x1, y1;
 		} else if ((tp->flgs & CHBRF(i)) == CHF(i))
 			gaps |= 1<<i;	/* empty stem */
 	}
-					/* now do branches */
+					/* do branches */
 	for (i = 0; i < 4; i++)
 		if ((tp->flgs & CHBRF(i)) == CHBRF(i)) {
 			update(rgb, tp->k[i].b, i&01 ? mx : x0, i&02 ? my : y0,
@@ -92,21 +117,27 @@ int	x0, y0, x1, y1;
 }
 
 
-qtRedraw(x0, y0, x1, y1)	/* redraw part or all of our screen */
-int	x0, y0, x1, y1;
+extern void
+qtRedraw(	/* redraw part or all of our screen */
+	int	x0,
+	int	y0,
+	int	x1,
+	int	y1
+)
 {
 	int	lim[2][2];
 
 	if (is_stump(&qtrunk))
 		return;
-	if (!qtMapLeaves((lim[0][0]=x0) <= 0 & (lim[1][0]=y0) <= 0 &
-		(lim[0][1]=x1) >= odev.hres-1 & (lim[1][1]=y1) >= odev.vres-1))
+	if (!qtMapLeaves(((lim[0][0]=x0) <= 0) & ((lim[1][0]=y0) <= 0) &
+		((lim[0][1]=x1) >= odev.hres-1) & ((lim[1][1]=y1) >= odev.vres-1)))
 		return;
 	redraw(&qtrunk, 0, 0, odev.hres, odev.vres, lim);
 }
 
 
-qtUpdate()			/* update our tree display */
+extern void
+qtUpdate(void)			/* update our tree display */
 {
 	BYTE	ca[3];