--- ray/src/rt/m_mirror.c	1992/11/20 12:09:16	2.2
+++ ray/src/rt/m_mirror.c	1995/09/15 15:47:29	2.6
@@ -1,4 +1,4 @@
-/* Copyright (c) 1991 Regents of the University of California */
+/* Copyright (c) 1995 Regents of the University of California */
 
 #ifndef lint
 static char SCCSid[] = "$SunId$ LBL";
@@ -36,6 +36,7 @@ register RAY  *r;
 {
 	COLOR  mcolor;
 	RAY  nr;
+	int  rpure = 1;
 	register int  i;
 					/* check arguments */
 	if (m->oargs.nfargs != 3 || m->oargs.nsargs > 1)
@@ -43,15 +44,18 @@ register RAY  *r;
 					/* check for substitute material */
 	if (m->oargs.nsargs > 0 &&
 			(r->rsrc < 0 || source[r->rsrc].so != r->ro)) {
-		rayshade(r, modifier(m->oargs.sarg[0]));
-		return;
+		if (!strcmp(m->oargs.sarg[0], VOIDID)) {
+			raytrans(r);
+			return(1);
+		}
+		return(rayshade(r, modifier(m->oargs.sarg[0])));
 	}
 					/* check for bad source ray */
 	if (r->rsrc >= 0 && source[r->rsrc].so != r->ro)
-		return;
+		return(1);
 
 	if (r->rod < 0.)		/* back is black */
-		return;
+		return(1);
 					/* get modifiers */
 	raytexture(r, m->omod);
 					/* assign material color */
@@ -72,18 +76,24 @@ register RAY  *r;
 		double  pdot;
 
 		if (rayorigin(&nr, r, REFLECTED, bright(mcolor)) < 0)
-			return;
-		pdot = raynormal(pnorm, r);	/* use textures */
-		for (i = 0; i < 3; i++)
-			nr.rdir[i] = r->rdir[i] + 2.*pdot*pnorm[i];
+			return(1);
+		if (DOT(r->pert,r->pert) > FTINY*FTINY) {
+			pdot = raynormal(pnorm, r);	/* use textures */
+			for (i = 0; i < 3; i++)
+				nr.rdir[i] = r->rdir[i] + 2.*pdot*pnorm[i];
+			rpure = 0;
+		}
 						/* check for penetration */
-		if (DOT(nr.rdir, r->ron) <= FTINY)
+		if (rpure || DOT(nr.rdir, r->ron) <= FTINY)
 			for (i = 0; i < 3; i++)
 				nr.rdir[i] = r->rdir[i] + 2.*r->rod*r->ron[i];
 	}
 	rayvalue(&nr);
 	multcolor(nr.rcol, mcolor);
 	addcolor(r->rcol, nr.rcol);
+	if (rpure && r->ro != NULL && isflat(r->ro->otype))
+		r->rt = r->rot + nr.rt;
+	return(1);
 }
 
 
@@ -93,12 +103,21 @@ register OBJREC  *o;
 SRCREC  *s;
 int  n;
 {
-	FVECT  nv;
+	FVECT  nv, sc;
 	double  od;
+	register int  i, j;
 				/* get surface normal and offset */
 	od = getplaneq(nv, o);
-				/* check for behind */
-	if (DOT(s->sloc, nv) <= (s->sflags & SDISTANT ? FTINY : od+FTINY))
+				/* check for extreme point for behind */
+	VCOPY(sc, s->sloc);
+	for (i = s->sflags & SFLAT ? SV : SW; i >= 0; i--)
+		if (DOT(nv, s->ss[i]) > 0.)
+			for (j = 0; j < 3; j++)
+				sc[j] += s->ss[i][j];
+		else
+			for (j = 0; j < 3; j++)
+				sc[j] -= s->ss[i][j];
+	if (DOT(sc, nv) <= (s->sflags & SDISTANT ? FTINY : od+FTINY))
 		return(0);
 				/* everything OK -- compute projection */
 	mirrorproj(pm, nv, od);