--- ray/src/rt/m_clip.c	2003/07/21 22:30:19	2.7
+++ ray/src/rt/m_clip.c	2013/08/20 21:37:46	2.11
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char	RCSid[] = "$Id: m_clip.c,v 2.7 2003/07/21 22:30:19 schorsch Exp $";
+static const char	RCSid[] = "$Id: m_clip.c,v 2.11 2013/08/20 21:37:46 greg Exp $";
 #endif
 /*
  *  m_clip.c - routine for clipped (cut) objects.
@@ -8,6 +8,7 @@ static const char	RCSid[] = "$Id: m_clip.c,v 2.7 2003/
 #include "copyright.h"
 
 #include  "ray.h"
+#include  "rtotypes.h"
 
 /*
  *  Clipping objects permit holes and sections to be taken out
@@ -19,14 +20,15 @@ static const char	RCSid[] = "$Id: m_clip.c,v 2.7 2003/
 
 
 int
-m_clip(m, r)			/* clip objects from ray */
-register OBJREC  *m;
-register RAY  *r;
+m_clip(			/* clip objects from ray */
+	OBJREC  *m,
+	RAY  *r
+)
 {
 	OBJECT  cset[MAXSET+1], *modset;
 	OBJECT  obj, mod;
 	int  entering;
-	register int  i;
+	int  i;
 
 	obj = objndx(m);
 	if ((modset = (OBJECT *)m->os) == NULL) {
@@ -53,30 +55,30 @@ register RAY  *r;
 		}
 		m->os = (char *)modset;
 	}
+	if (r == NULL)
+		return(0);			/* just initializing */
 	if (r->clipset != NULL)
 		setcopy(cset, r->clipset);
 	else
 		cset[0] = 0;
 
-	entering = r->rod > 0.0;		/* entering clipped region? */
+	entering = (r->rod > 0.0);		/* entering clipped region? */
 
-	for (i = modset[0]; i > 0; i--) {
+	for (i = modset[0]; i > 0; i--)
 		if (entering) {
 			if (!inset(cset, modset[i])) {
 				if (cset[0] >= MAXSET)
 					error(INTERNAL, "set overflow in m_clip");
 				insertelem(cset, modset[i]);
 			}
-		} else {
-			if (inset(cset, modset[i]))
-				deletelem(cset, modset[i]);
-		}
-	}
+		} else if (inset(cset, modset[i]))
+			deletelem(cset, modset[i]);
+
 					/* compute ray value */
 	r->newcset = cset;
 	if (strcmp(m->oargs.sarg[0], VOIDID)) {
 		int  inside = 0;
-		register RAY  *rp;
+		const RAY  *rp;
 					/* check for penetration */
 		for (rp = r; rp->parent != NULL; rp = rp->parent)
 			if (!(rp->rtype & RAYREFL) && rp->parent->ro != NULL