--- ray/src/rt/raytrace.c	1991/10/23 13:43:45	1.23
+++ ray/src/rt/raytrace.c	1993/02/23 13:57:11	2.4
@@ -18,6 +18,8 @@ static char SCCSid[] = "$SunId$ LBL";
 
 #include  "otspecial.h"
 
+#define  MAXCSET	((MAXSET+1)*2-1)	/* maximum check set size */
+
 extern CUBE  thescene;			/* our scene */
 extern int  maxdepth;			/* maximum recursion depth */
 extern double  minweight;		/* minimum ray weight */
@@ -29,7 +31,7 @@ long  nrays = 0L;			/* number of calls to localhit */
 static FLOAT  Lambfa[5] = {PI, PI, PI, 0.0, 0.0};
 OBJREC  Lamb = {
 	OVOID, MAT_PLASTIC, "Lambertian",
-	{0, 5, NULL, Lambfa}, NULL, -1,
+	{0, 5, NULL, Lambfa}, NULL,
 };					/* a Lambertian surface */
 
 #define  MAXLOOP	128		/* modifier loop detection */
@@ -151,7 +153,6 @@ int  mod;
 				m = &Lamb;
 		}
 		(*ofun[m->otype].funp)(m, r);	/* execute function */
-		m->lastrno = r->rno;
 		if (ismaterial(m->otype)) {	/* materials call raytexture */
 			depth--;
 			return;		/* we're done */
@@ -178,7 +179,6 @@ int  mod;
 			error(USER, errmsg);
 		}
 		(*ofun[m->otype].funp)(m, r);
-		m->lastrno = r->rno;
 	}
 	depth--;			/* end here */
 }
@@ -318,6 +318,7 @@ localhit(r, scene)		/* check for hit in the octree */
 register RAY  *r;
 register CUBE  *scene;
 {
+	OBJECT  cxset[MAXCSET+1];	/* set of checked objects */
 	FVECT  curpos;			/* current cube position */
 	int  sflags;			/* sign flags */
 	double  t, dt;
@@ -358,13 +359,15 @@ register CUBE  *scene;
 		if (!incube(scene, curpos))	/* non-intersecting ray */
 			return(0);
 	}
-	return(raymove(curpos, sflags, r, scene) == RAYHIT);
+	cxset[0] = 0;
+	return(raymove(curpos, cxset, sflags, r, scene) == RAYHIT);
 }
 
 
 static int
-raymove(pos, dirf, r, cu)		/* check for hit as we move */
-FVECT  pos;			/* modified */
+raymove(pos, cxs, dirf, r, cu)		/* check for hit as we move */
+FVECT  pos;			/* current position, modified herein */
+OBJECT  *cxs;			/* checked objects, modified by checkhit */
 int  dirf;			/* direction indicators to speed tests */
 register RAY  *r;
 register CUBE  *cu;
@@ -393,7 +396,7 @@ register CUBE  *cu;
 		}
 		for ( ; ; ) {
 			cukid.cutree = octkid(cu->cutree, br);
-			if ((ax = raymove(pos,dirf,r,&cukid)) == RAYHIT)
+			if ((ax = raymove(pos,cxs,dirf,r,&cukid)) == RAYHIT)
 				return(RAYHIT);
 			sgn = 1 << ax;
 			if (sgn & dirf)			/* positive axis? */
@@ -412,7 +415,7 @@ register CUBE  *cu;
 		}
 		/*NOTREACHED*/
 	}
-	if (isfull(cu->cutree) && checkhit(r, cu))
+	if (isfull(cu->cutree) && checkhit(r, cu, cxs))
 		return(RAYHIT);
 					/* advance to next cube */
 	if (dirf&0x11) {
@@ -445,24 +448,57 @@ register CUBE  *cu;
 
 
 static
-checkhit(r, cu)			/* check for hit in full cube */
+checkhit(r, cu, cxs)		/* check for hit in full cube */
 register RAY  *r;
 CUBE  *cu;
+OBJECT  *cxs;
 {
 	OBJECT  oset[MAXSET+1];
 	register OBJREC  *o;
 	register int  i;
 
 	objset(oset, cu->cutree);
+	checkset(oset, cxs);			/* eliminate double-checking */
 	for (i = oset[0]; i > 0; i--) {
 		o = objptr(oset[i]);
-		if (o->lastrno == r->rno)		/* checked already? */
-			continue;
+		if (o->omod == OVOID && issurface(o->otype))
+			continue;		/* ignore void surfaces */
 		(*ofun[o->otype].funp)(o, r);
-		o->lastrno = r->rno;
 	}
 	if (r->ro == NULL)
 		return(0);			/* no scores yet */
 
 	return(incube(cu, r->rop));		/* hit OK if in current cube */
+}
+
+
+static
+checkset(os, cs)		/* modify checked set and set to check */
+register OBJECT  *os;			/* os' = os - cs */
+register OBJECT  *cs;			/* cs' = cs + os */
+{
+	OBJECT  cset[MAXCSET+MAXSET+1];
+	register int  i, j;
+	int  k;
+					/* copy os in place, cset <- cs */
+	cset[0] = 0;
+	k = 0;
+	for (i = j = 1; i <= os[0]; i++) {
+		while (j <= cs[0] && cs[j] < os[i])
+			cset[++cset[0]] = cs[j++];
+		if (j > cs[0] || os[i] != cs[j]) {	/* object to check */
+			os[++k] = os[i];
+			cset[++cset[0]] = os[i];
+		}
+	}
+	if (!(os[0] = k))		/* new "to check" set size */
+		return;			/* special case */
+	while (j <= cs[0])		/* get the rest of cs */
+		cset[++cset[0]] = cs[j++];
+	if (cset[0] > MAXCSET)		/* truncate "checked" set if nec. */
+		cset[0] = MAXCSET;
+	/* setcopy(cs, cset); */	/* copy cset back to cs */
+	os = cset;
+	for (i = os[0]; i-- >= 0; )
+		*cs++ = *os++;
 }