--- ray/src/ot/o_face.c	1989/02/02 10:33:03	1.1
+++ ray/src/ot/o_face.c	2004/03/27 12:41:45	2.4
@@ -1,9 +1,6 @@
-/* Copyright (c) 1986 Regents of the University of California */
-
 #ifndef lint
-static char SCCSid[] = "$SunId$ LBL";
+static const char	RCSid[] = "$Id: o_face.c,v 2.4 2004/03/27 12:41:45 schorsch Exp $";
 #endif
-
 /*
  *  o_face.c - routines for creating octrees for polygonal faces.
  *
@@ -40,10 +37,12 @@ static char SCCSid[] = "$SunId$ LBL";
  *	5) If test 4 fails, we have no intersection.
  */
 
-
-o_face(o, cu)			/* determine if face intersects cube */
-OBJREC  *o;
-CUBE  *cu;
+/* XXX this is extern, but not declared in any header file yet */
+int
+o_face(			/* determine if face intersects cube */
+	OBJREC  *o,
+	CUBE  *cu
+)
 {
 	FVECT  cumin, cumax;
 	FVECT  v1, v2;
@@ -54,20 +53,21 @@ CUBE  *cu;
 				/* get face arguments */
 	f = getface(o);
 	if (f->area == 0.0)		/* empty face */
-		return(0);
+		return(O_MISS);
 					/* compute cube boundaries */
 	for (j = 0; j < 3; j++)
-		cumax[j] = (cumin[j] = cu->cuorg[j]) + cu->cusize;
+		cumax[j] = (cumin[j] = cu->cuorg[j]-FTINY)
+				+ cu->cusize + 2.0*FTINY;
 
 	vloc = ABOVE | BELOW;		/* check vertices */
 	for (i = 0; i < f->nv; i++)
-		if (j = plocate(VERTEX(f,i), cumin, cumax))
+		if ( (j = plocate(VERTEX(f,i), cumin, cumax)) )
 			vloc &= j;
 		else
-			return(1);	/* vertex inside */
+			return(O_HIT);	/* vertex inside */
 
 	if (vloc)			/* all to one side */
-		return(0);
+		return(O_MISS);
 	
 	for (i = 0; i < f->nv; i++) {	/* check edges */
 		if ((j = i + 1) >= f->nv)
@@ -75,7 +75,7 @@ CUBE  *cu;
 		VCOPY(v1, VERTEX(f,i));		/* clip modifies */
 		VCOPY(v2, VERTEX(f,j));		/* the vertices! */
 		if (clip(v1, v2, cumin, cumax))
-			return(1);		/* edge inside */
+			return(O_HIT);		/* edge inside */
 	}
 					/* see if cube cuts plane */
 	for (j = 0; j < 3; j++)
@@ -86,15 +86,15 @@ CUBE  *cu;
 			v1[j] = cumax[j];
 			v2[j] = cumin[j];
 		}
-	if ((d1 = DOT(v1, f->norm) - f->const) > FTINY)
-		return(0);
-	if ((d2 = DOT(v2, f->norm) - f->const) < -FTINY)
-		return(0);
+	if ((d1 = DOT(v1, f->norm) - f->offset) > FTINY)
+		return(O_MISS);
+	if ((d2 = DOT(v2, f->norm) - f->offset) < -FTINY)
+		return(O_MISS);
 					/* intersect face */
 	for (j = 0; j < 3; j++)
 		v1[j] = (v1[j]*d2 - v2[j]*d1)/(d2 - d1);
 	if (inface(v1, f))
-		return(1);
+		return(O_HIT);
 	
-	return(0);		/* no intersection */
+	return(O_MISS);		/* no intersection */
 }