--- ray/src/rt/normal.c	2004/03/30 16:13:01	2.47
+++ ray/src/rt/normal.c	2005/01/05 19:34:11	2.49
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: normal.c,v 2.47 2004/03/30 16:13:01 schorsch Exp $";
+static const char RCSid[] = "$Id: normal.c,v 2.49 2005/01/05 19:34:11 greg Exp $";
 #endif
 /*
  *  normal.c - shading function for normal materials.
@@ -78,7 +78,7 @@ dirnorm(		/* compute source contribution */
 {
 	register NORMDAT *np = nnp;
 	double  ldot;
-	double  ldiff;
+	double  lrdiff, ltdiff;
 	double  dtmp, d2;
 	FVECT  vtmp;
 	COLOR  ctmp;
@@ -91,18 +91,23 @@ dirnorm(		/* compute source contribution */
 		return;		/* wrong side */
 
 				/* Fresnel estimate */
-	ldiff = np->rdiff;
-	if (np->specfl & SP_PURE && (np->rspec > FTINY) & (ldiff > FTINY))
-		ldiff *= 1. - FRESNE(fabs(ldot));
+	lrdiff = np->rdiff;
+	ltdiff = np->tdiff;
+	if (np->specfl & SP_PURE && np->rspec > FTINY &&
+			(lrdiff > FTINY) | (ltdiff > FTINY)) {
+		dtmp = 1. - FRESNE(fabs(ldot));
+		lrdiff *= dtmp;
+		ltdiff *= dtmp;
+	}
 
-	if (ldot > FTINY && ldiff > FTINY) {
+	if (ldot > FTINY && lrdiff > FTINY) {
 		/*
 		 *  Compute and add diffuse reflected component to returned
 		 *  color.  The diffuse reflected component will always be
 		 *  modified by the color of the material.
 		 */
 		copycolor(ctmp, np->mcolor);
-		dtmp = ldot * omega * ldiff / PI;
+		dtmp = ldot * omega * lrdiff * (1.0/PI);
 		scalecolor(ctmp, dtmp);
 		addcolor(cval, ctmp);
 	}
@@ -115,7 +120,7 @@ dirnorm(		/* compute source contribution */
 		dtmp = np->alpha2;
 						/* + source if flat */
 		if (np->specfl & SP_FLAT)
-			dtmp += omega/(4.0*PI);
+			dtmp += omega * (0.25/PI);
 						/* half vector */
 		vtmp[0] = ldir[0] - np->rp->rdir[0];
 		vtmp[1] = ldir[1] - np->rp->rdir[1];
@@ -124,21 +129,21 @@ dirnorm(		/* compute source contribution */
 		d2 *= d2;
 		d2 = (DOT(vtmp,vtmp) - d2) / d2;
 						/* gaussian */
-		dtmp = exp(-d2/dtmp)/(4.*PI*dtmp);
+		dtmp = exp(-d2/dtmp)/(4.*PI * np->pdot * dtmp);
 						/* worth using? */
 		if (dtmp > FTINY) {
 			copycolor(ctmp, np->scolor);
-			dtmp *= omega * sqrt(ldot/np->pdot);
+			dtmp *= omega;
 			scalecolor(ctmp, dtmp);
 			addcolor(cval, ctmp);
 		}
 	}
-	if (ldot < -FTINY && np->tdiff > FTINY) {
+	if (ldot < -FTINY && ltdiff > FTINY) {
 		/*
 		 *  Compute diffuse transmission.
 		 */
 		copycolor(ctmp, np->mcolor);
-		dtmp = -ldot * omega * np->tdiff / PI;
+		dtmp = -ldot * omega * ltdiff * (1.0/PI);
 		scalecolor(ctmp, dtmp);
 		addcolor(cval, ctmp);
 	}
@@ -148,13 +153,14 @@ dirnorm(		/* compute source contribution */
 		 *  is always modified by material color.
 		 */
 						/* roughness + source */
-		dtmp = np->alpha2 + omega/PI;
+		dtmp = np->alpha2 + omega*(1.0/PI);
 						/* gaussian */
-		dtmp = exp((2.*DOT(np->prdir,ldir)-2.)/dtmp)/(PI*dtmp);
+		dtmp = exp((2.*DOT(np->prdir,ldir)-2.)/dtmp) /
+					(PI*np->pdot*dtmp);
 						/* worth using? */
 		if (dtmp > FTINY) {
 			copycolor(ctmp, np->mcolor);
-			dtmp *= np->tspec * omega * sqrt(-ldot/np->pdot);
+			dtmp *= np->tspec * omega;
 			scalecolor(ctmp, dtmp);
 			addcolor(cval, ctmp);
 		}