--- ray/src/rt/dielectric.c	2003/02/22 02:07:28	2.15
+++ ray/src/rt/dielectric.c	2010/09/26 15:51:15	2.21
@@ -1,77 +1,25 @@
 #ifndef lint
-static const char	RCSid[] = "$Id: dielectric.c,v 2.15 2003/02/22 02:07:28 greg Exp $";
+static const char	RCSid[] = "$Id: dielectric.c,v 2.21 2010/09/26 15:51:15 greg Exp $";
 #endif
 /*
  *  dielectric.c - shading function for transparent materials.
  */
 
-/* ====================================================================
- * The Radiance Software License, Version 1.0
- *
- * Copyright (c) 1990 - 2002 The Regents of the University of California,
- * through Lawrence Berkeley National Laboratory.   All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- *         notice, this list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright
- *       notice, this list of conditions and the following disclaimer in
- *       the documentation and/or other materials provided with the
- *       distribution.
- *
- * 3. The end-user documentation included with the redistribution,
- *           if any, must include the following acknowledgment:
- *             "This product includes Radiance software
- *                 (http://radsite.lbl.gov/)
- *                 developed by the Lawrence Berkeley National Laboratory
- *               (http://www.lbl.gov/)."
- *       Alternately, this acknowledgment may appear in the software itself,
- *       if and wherever such third-party acknowledgments normally appear.
- *
- * 4. The names "Radiance," "Lawrence Berkeley National Laboratory"
- *       and "The Regents of the University of California" must
- *       not be used to endorse or promote products derived from this
- *       software without prior written permission. For written
- *       permission, please contact radiance@radsite.lbl.gov.
- *
- * 5. Products derived from this software may not be called "Radiance",
- *       nor may "Radiance" appear in their name, without prior written
- *       permission of Lawrence Berkeley National Laboratory.
- *
- * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
- * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
- * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
- * DISCLAIMED.   IN NO EVENT SHALL Lawrence Berkeley National Laboratory OR
- * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
- * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
- * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- * ====================================================================
- *
- * This software consists of voluntary contributions made by many
- * individuals on behalf of Lawrence Berkeley National Laboratory.   For more
- * information on Lawrence Berkeley National Laboratory, please see
- * <http://www.lbl.gov/>.
- */
+#include "copyright.h"
 
 #include  "ray.h"
-
 #include  "otypes.h"
+#include  "rtotypes.h"
 
 #ifdef  DISPERSE
 #include  "source.h"
-static  disperse();
-static int  lambda();
+static int disperse(OBJREC *m,RAY *r,FVECT vt,double tr,COLOR cet,COLOR abt);
+static int lambda(OBJREC  *m, FVECT  v2, FVECT  dv, FVECT  lr);
 #endif
 
+static double mylog(double  x);
+
+
 /*
  *     Explicit calculations for Fresnel's equation are performed,
  *  but only one square root computation is necessary.
@@ -104,8 +52,9 @@ static int  lambda();
 
 
 static double
-mylog(x)		/* special log for extinction coefficients */
-double  x;
+mylog(		/* special log for extinction coefficients */
+	double  x
+)
 {
 	if (x < 1e-40)
 		return(-100.);
@@ -115,14 +64,19 @@ double  x;
 }
 
 
-m_dielectric(m, r)	/* color a ray which hit a dielectric interface */
-OBJREC  *m;
-register RAY  *r;
+extern int
+m_dielectric(	/* color a ray which hit a dielectric interface */
+	OBJREC  *m,
+	register RAY  *r
+)
 {
 	double  cos1, cos2, nratio;
 	COLOR  ctrans;
 	COLOR  talb;
 	int  hastexture;
+	double  transdist, transtest=0;
+	double  mirdist, mirtest=0;
+	int	flatsurface;
 	double  refl, trans;
 	FVECT  dnorm;
 	double  d1, d2;
@@ -134,12 +88,14 @@ register RAY  *r;
 
 	raytexture(r, m->omod);			/* get modifiers */
 
-	if (hastexture = DOT(r->pert,r->pert) > FTINY*FTINY)
+	if ( (hastexture = DOT(r->pert,r->pert) > FTINY*FTINY) )
 		cos1 = raynormal(dnorm, r);	/* perturb normal */
 	else {
 		VCOPY(dnorm, r->ron);
 		cos1 = r->rod;
 	}
+	flatsurface = !hastexture && r->ro != NULL && isflat(r->ro->otype);
+
 						/* index of refraction */
 	if (m->otype == MAT_DIELECTRIC)
 		nratio = m->oargs.farg[3] + m->oargs.farg[4]/MLAMBDA;
@@ -208,8 +164,10 @@ register RAY  *r;
 
 		trans *= nratio*nratio;		/* solid angle ratio */
 
-		if (rayorigin(&p, r, REFRACTED, trans) == 0) {
+		setcolor(p.rcoef, trans, trans, trans);
 
+		if (rayorigin(&p, REFRACTED, r, p.rcoef) == 0) {
+
 						/* compute refracted ray */
 			d1 = nratio*cos1 - cos2;
 			for (i = 0; i < 3; i++)
@@ -222,7 +180,8 @@ register RAY  *r;
 					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
@@ -236,16 +195,22 @@ register RAY  *r;
 				copycolor(p.cext, ctrans);
 				copycolor(p.albedo, talb);
 				rayvalue(&p);
-				scalecolor(p.rcol, trans);
+				multcolor(p.rcol, p.rcoef);
 				addcolor(r->rcol, p.rcol);
-				if (nratio >= 1.0-FTINY && nratio <= 1.0+FTINY)
-					r->rt = r->rot + p.rt;
+						/* virtual distance */
+				if (flatsurface ||
+					(1.-FTINY <= nratio &&
+						nratio <= 1.+FTINY)) {
+					transtest = 2*bright(p.rcol);
+					transdist = r->rot + p.rt;
+				}
 			}
 		}
 	}
-		
+	setcolor(p.rcoef, refl, refl, refl);
+
 	if (!(r->crtype & SHADOW) &&
-			rayorigin(&p, r, REFLECTED, refl) == 0) {
+			rayorigin(&p, REFLECTED, r, p.rcoef) == 0) {
 
 					/* compute reflected ray */
 		for (i = 0; i < 3; i++)
@@ -254,12 +219,23 @@ register RAY  *r;
 		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];
-
+		checknorm(p.rdir);
 		rayvalue(&p);			/* reflected ray value */
 
-		scalecolor(p.rcol, refl);	/* color contribution */
+		multcolor(p.rcol, p.rcoef);	/* color contribution */
 		addcolor(r->rcol, p.rcol);
+						/* virtual distance */
+		if (flatsurface) {
+			mirtest = 2*bright(p.rcol);
+			mirdist = r->rot + p.rt;
+		}
 	}
+				/* check distance to return */
+	d1 = bright(r->rcol);
+	if (transtest > d1)
+		r->rt = transdist;
+	else if (mirtest > d1)
+		r->rt = mirdist;
 				/* rayvalue() computes absorption */
 	return(1);
 }
@@ -267,15 +243,18 @@ register RAY  *r;
 
 #ifdef  DISPERSE
 
-static
-disperse(m, r, vt, tr, cet, abt)  /* check light sources for dispersion */
-OBJREC  *m;
-RAY  *r;
-FVECT  vt;
-double  tr;
-COLOR  cet, abt;
+static int
+disperse(  /* check light sources for dispersion */
+	OBJREC  *m,
+	RAY  *r,
+	FVECT  vt,
+	double  tr,
+	COLOR  cet,
+	COLOR  abt
+)
 {
-	RAY  sray, *entray;
+	RAY  sray;
+	const RAY  *entray;
 	FVECT  v1, v2, n1, n2;
 	FVECT  dv, v2Xdv;
 	double  v2Xdvv2Xdv;
@@ -404,9 +383,12 @@ COLOR  cet, abt;
 
 
 static int
-lambda(m, v2, dv, lr)			/* compute lambda for material */
-register OBJREC  *m;
-FVECT  v2, dv, lr;
+lambda(			/* compute lambda for material */
+	register OBJREC  *m,
+	FVECT  v2,
+	FVECT  dv,
+	FVECT  lr
+)
 {
 	FVECT  lrXdv, v2Xlr;
 	double  dtmp, denom;