--- ray/src/rt/dielectric.c	2005/04/19 01:15:06	2.20
+++ ray/src/rt/dielectric.c	2014/05/10 17:43:01	2.24
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char	RCSid[] = "$Id: dielectric.c,v 2.20 2005/04/19 01:15:06 greg Exp $";
+static const char	RCSid[] = "$Id: dielectric.c,v 2.24 2014/05/10 17:43:01 greg Exp $";
 #endif
 /*
  *  dielectric.c - shading function for transparent materials.
@@ -64,24 +64,24 @@ mylog(		/* special log for extinction coefficients */
 }
 
 
-extern int
+int
 m_dielectric(	/* color a ray which hit a dielectric interface */
 	OBJREC  *m,
-	register RAY  *r
+	RAY  *r
 )
 {
 	double  cos1, cos2, nratio;
 	COLOR  ctrans;
 	COLOR  talb;
 	int  hastexture;
-	double  transdist, transtest=0;
-	double  mirdist, mirtest=0;
+	double  transdist=0, transtest=0;
+	double  mirdist=0, mirtest=0;
 	int	flatsurface;
 	double  refl, trans;
 	FVECT  dnorm;
 	double  d1, d2;
 	RAY  p;
-	register int  i;
+	int  i;
 
 	if (m->oargs.nfargs != (m->otype==MAT_DIELECTRIC ? 5 : 8))
 		objerror(m, USER, "bad arguments");
@@ -94,7 +94,8 @@ m_dielectric(	/* color a ray which hit a dielectric in
 		VCOPY(dnorm, r->ron);
 		cos1 = r->rod;
 	}
-	flatsurface = !hastexture && r->ro != NULL && isflat(r->ro->otype);
+	flatsurface = r->ro != NULL && isflat(r->ro->otype) &&
+			!hastexture | (r->crtype & AMBIENT);
 
 						/* index of refraction */
 	if (m->otype == MAT_DIELECTRIC)
@@ -180,7 +181,8 @@ m_dielectric(	/* color a ray which hit a dielectric in
 					p.rdir[i] = nratio*r->rdir[i] +
 							d1*r->ron[i];
 				normalize(p.rdir);	/* not exact */
-			}
+			} else
+				checknorm(p.rdir);
 #ifdef  DISPERSE
 			if (m->otype != MAT_DIELECTRIC
 					|| r->rod > 0.0
@@ -198,8 +200,8 @@ m_dielectric(	/* color a ray which hit a dielectric in
 				addcolor(r->rcol, p.rcol);
 						/* virtual distance */
 				if (flatsurface ||
-					(1.-FTINY <= nratio &&
-						nratio <= 1.+FTINY)) {
+					(1.-FTINY <= nratio) &
+						(nratio <= 1.+FTINY)) {
 					transtest = 2*bright(p.rcol);
 					transdist = r->rot + p.rt;
 				}
@@ -212,13 +214,11 @@ m_dielectric(	/* color a ray which hit a dielectric in
 			rayorigin(&p, REFLECTED, r, p.rcoef) == 0) {
 
 					/* compute reflected ray */
-		for (i = 0; i < 3; i++)
-			p.rdir[i] = r->rdir[i] + 2.0*cos1*dnorm[i];
+		VSUM(p.rdir, r->rdir, dnorm, 2.*cos1);
 					/* accidental penetration? */
 		if (hastexture && DOT(p.rdir,r->ron)*hastexture <= FTINY)
-			for (i = 0; i < 3; i++)		/* ignore texture */
-				p.rdir[i] = r->rdir[i] + 2.0*r->rod*r->ron[i];
-
+			VSUM(p.rdir, r->rdir, r->ron, 2.*r->rod);
+		checknorm(p.rdir);
 		rayvalue(&p);			/* reflected ray value */
 
 		multcolor(p.rcol, p.rcoef);	/* color contribution */
@@ -308,10 +308,10 @@ disperse(  /* check light sources for dispersion */
 	VCOPY(n2, r->ron);
 
 					/* first order dispersion approx. */
-	dtmp1 = DOT(n1, v1);
-	dtmp2 = DOT(n2, v2);
+	dtmp1 = 1./DOT(n1, v1);
+	dtmp2 = 1./DOT(n2, v2);
 	for (i = 0; i < 3; i++)
-		dv[i] = v1[i] + v2[i] - n1[i]/dtmp1 - n2[i]/dtmp2;
+		dv[i] = v1[i] + v2[i] - n1[i]*dtmp1 - n2[i]*dtmp2;
 		
 	if (DOT(dv, dv) <= FTINY)	/* null effect */
 		return(0);
@@ -354,15 +354,13 @@ disperse(  /* check light sources for dispersion */
 		dtmp1 = sqrt(si.dom  / v2Xdvv2Xdv / PI);
 
 							/* compute first ray */
-		for (i = 0; i < 3; i++)
-			vtmp2[i] = sray.rdir[i] + dtmp1*vtmp1[i];
+		VSUM(vtmp2, sray.rdir, vtmp1, dtmp1);
 
 		l1 = lambda(m, v2, dv, vtmp2);		/* first lambda */
 		if (l1 < 0)
 			continue;
 							/* compute second ray */
-		for (i = 0; i < 3; i++)
-			vtmp2[i] = sray.rdir[i] - dtmp1*vtmp1[i];
+		VSUM(vtmp2, sray.rdir, vtmp1, -dtmp1);
 
 		l2 = lambda(m, v2, dv, vtmp2);		/* second lambda */
 		if (l2 < 0)
@@ -383,7 +381,7 @@ disperse(  /* check light sources for dispersion */
 
 static int
 lambda(			/* compute lambda for material */
-	register OBJREC  *m,
+	OBJREC  *m,
 	FVECT  v2,
 	FVECT  dv,
 	FVECT  lr
@@ -395,7 +393,7 @@ lambda(			/* compute lambda for material */
 
 	fcross(lrXdv, lr, dv);
 	for (i = 0; i < 3; i++)	
-		if (lrXdv[i] > FTINY || lrXdv[i] < -FTINY)
+		if ((lrXdv[i] > FTINY) | (lrXdv[i] < -FTINY))
 			break;
 	if (i >= 3)
 		return(-1);