--- ray/src/rt/dielectric.c	1992/10/02 16:17:04	2.2
+++ ray/src/rt/dielectric.c	1993/11/18 09:43:00	2.6
@@ -16,6 +16,8 @@ static char SCCSid[] = "$SunId$ LBL";
 
 #ifdef  DISPERSE
 #include  "source.h"
+static  disperse();
+static int  lambda();
 #endif
 
 /*
@@ -65,8 +67,6 @@ register RAY  *r;
 	if (m->oargs.nfargs != (m->otype==MAT_DIELECTRIC ? 5 : 8))
 		objerror(m, USER, "bad arguments");
 
-	r->rt = r->rot;				/* just use ray length */
-
 	raytexture(r, m->omod);			/* get modifiers */
 
 	cos1 = raynormal(dnorm, r);		/* cosine of theta1 */
@@ -128,7 +128,7 @@ register RAY  *r;
 			if (m->otype != MAT_DIELECTRIC
 					|| r->rod > 0.0
 					|| r->crtype & SHADOW
-					|| directinvis
+					|| !directvis
 					|| m->oargs.farg[4] == 0.0
 					|| !disperse(m, r, p.rdir, trans))
 #endif
@@ -137,6 +137,8 @@ register RAY  *r;
 				multcolor(mcolor, r->pcol);	/* modify */
 				scalecolor(p.rcol, trans);
 				addcolor(r->rcol, p.rcol);
+				if (nratio >= 1.0-FTINY && nratio <= 1.0+FTINY)
+					r->rt = r->rot + p.rt;
 			}
 		}
 	}