--- ray/src/rt/raytrace.c	1994/01/25 10:18:25	2.14
+++ ray/src/rt/raytrace.c	1995/12/06 12:07:50	2.22
@@ -1,4 +1,4 @@
-/* Copyright (c) 1994 Regents of the University of California */
+/* Copyright (c) 1995 Regents of the University of California */
 
 #ifndef lint
 static char SCCSid[] = "$SunId$ LBL";
@@ -34,6 +34,8 @@ OBJREC  Lamb = {
 	{0, 5, NULL, Lambfa}, NULL,
 };					/* a Lambertian surface */
 
+OBJREC  Aftplane;			/* aft clipping plane object */
+
 static int  raymove(), checkset(), checkhit();
 
 #define  MAXLOOP	128		/* modifier loop detection */
@@ -59,9 +61,11 @@ double  rw;
 			r->rlvl++;
 			r->rsrc = -1;
 			r->clipset = ro->clipset;
+			r->rmax = 0.0;
 		} else {
 			r->rsrc = ro->rsrc;
 			r->clipset = ro->newcset;
+			r->rmax = ro->rmax <= FTINY ? 0.0 : ro->rmax - ro->rot;
 		}
 		r->revf = ro->revf;
 		r->rweight = ro->rweight * rw;
@@ -95,7 +99,10 @@ RAY  *r;
 
 	if (localhit(r, &thescene))
 		gotmat = raycont(r);
-	else if (sourcehit(r))
+	else if (r->ro == &Aftplane) {
+		r->ro = NULL;
+		r->rot = FHUGE;
+	} else if (sourcehit(r))
 		gotmat = rayshade(r, r->ro->omod);
 
 	if (r->ro != NULL && !gotmat)
@@ -156,7 +163,7 @@ int  mod;
 			if (irr_ignore(m->otype)) {
 				depth--;
 				raytrans(r);
-				return;
+				return(1);
 			}
 			if (!islight(m->otype))
 				m = &Lamb;
@@ -187,8 +194,11 @@ int  mod;
 			error(USER, errmsg);
 		}
 		******/
-		if ((*ofun[m->otype].funp)(m, r))
-			objerror(r->ro, USER, "conflicting materials");
+		if ((*ofun[m->otype].funp)(m, r)) {
+			sprintf(errmsg, "conflicting material \"%s\"",
+					m->oname);
+			objerror(r->ro, USER, errmsg);
+		}
 	}
 	depth--;			/* end here */
 }
@@ -249,6 +259,21 @@ double  coef;
 
 
 double
+raydist(r, flags)		/* compute (cumulative) ray distance */
+register RAY  *r;
+register int  flags;
+{
+	double  sum = 0.0;
+
+	while (r != NULL && r->crtype&flags) {
+		sum += r->rot;
+		r = r->parent;
+	}
+	return(sum);
+}
+
+
+double
 raynormal(norm, r)		/* compute perturbed normal for ray */
 FVECT  norm;
 register RAY  *r;
@@ -353,6 +378,14 @@ register CUBE  *scene;
 	}
 	if (sflags == 0)
 		error(CONSISTENCY, "zero ray direction in localhit");
+					/* start off assuming nothing hit */
+	if (r->rmax > FTINY) {		/* except aft plane if one */
+		r->ro = &Aftplane;
+		r->rot = r->rmax;
+		for (i = 0; i < 3; i++)
+			r->rop[i] = r->rorg[i] + r->rot*r->rdir[i];
+	}
+					/* find global cube entrance point */
 	t = 0.0;
 	if (!incube(scene, curpos)) {
 					/* find distance to entry */
@@ -370,6 +403,8 @@ register CUBE  *scene;
 				t = dt;	/* farthest face is the one */
 		}
 		t += FTINY;		/* fudge to get inside cube */
+		if (t >= r->rot)	/* clipped already */
+			return(0);
 					/* advance position */
 		for (i = 0; i < 3; i++)
 			curpos[i] += r->rdir[i]*t;
@@ -378,7 +413,8 @@ register CUBE  *scene;
 			return(0);
 	}
 	cxset[0] = 0;
-	return(raymove(curpos, cxset, sflags, r, scene) == RAYHIT);
+	raymove(curpos, cxset, sflags, r, scene);
+	return(r->ro != NULL & r->ro != &Aftplane);
 }
 
 
@@ -433,7 +469,10 @@ register CUBE  *cu;
 		}
 		/*NOTREACHED*/
 	}
-	if (isfull(cu->cutree) && checkhit(r, cu, cxs))
+	if (isfull(cu->cutree)) {
+		if (checkhit(r, cu, cxs))
+			return(RAYHIT);
+	} else if (r->ro == &Aftplane && incube(cu, r->rop))
 		return(RAYHIT);
 					/* advance to next cube */
 	if (dirf&0x11) {