--- ray/src/rt/normal.c	1992/04/16 13:31:28	2.13
+++ ray/src/rt/normal.c	1992/05/19 17:09:03	2.20
@@ -50,6 +50,7 @@ extern double  specjitter;		/* specular sampling jitte
 
 typedef struct {
 	OBJREC  *mp;		/* material pointer */
+	RAY  *rp;		/* ray pointer */
 	short  specfl;		/* specularity flags, defined above */
 	COLOR  mcolor;		/* color of this material */
 	COLOR  scolor;		/* color of specular component */
@@ -71,8 +72,8 @@ FVECT  ldir;			/* light source direction */
 double  omega;			/* light source size */
 {
 	double  ldot;
-	double  dtmp;
-	int	i;
+	double  dtmp, d2;
+	FVECT  vtmp;
 	COLOR  ctmp;
 
 	setcolor(cval, 0.0, 0.0, 0.0);
@@ -99,16 +100,22 @@ double  omega;			/* light source size */
 		 *  gaussian distribution model.
 		 */
 						/* roughness */
-		dtmp = 2.0*np->alpha2;
+		dtmp = np->alpha2;
 						/* + source if flat */
 		if (np->specfl & SP_FLAT)
-			dtmp += omega/(2.0*PI);
+			dtmp += omega/(4.0*PI);
+						/* delta */
+		vtmp[0] = ldir[0] - np->rp->rdir[0];
+		vtmp[1] = ldir[1] - np->rp->rdir[1];
+		vtmp[2] = ldir[2] - np->rp->rdir[2];
+		d2 = DOT(vtmp, np->pnorm);
+		d2 = 2.0 - 2.0*d2/sqrt(DOT(vtmp,vtmp));
 						/* gaussian */
-		dtmp = exp((DOT(np->vrefl,ldir)-1.)/dtmp)/(2.*PI)/dtmp;
+		dtmp = exp(-d2/dtmp)/(4.*PI*dtmp);
 						/* worth using? */
 		if (dtmp > FTINY) {
 			copycolor(ctmp, np->scolor);
-			dtmp *= omega / np->pdot;
+			dtmp *= omega * sqrt(ldot/np->pdot);
 			scalecolor(ctmp, dtmp);
 			addcolor(cval, ctmp);
 		}
@@ -128,13 +135,13 @@ double  omega;			/* light source size */
 		 *  is always modified by material color.
 		 */
 						/* roughness + source */
-		dtmp = np->alpha2/2.0 + omega/(2.0*PI);
+		dtmp = np->alpha2 + omega/PI;
 						/* gaussian */
-		dtmp = exp((DOT(np->prdir,ldir)-1.)/dtmp)/(2.*PI)/dtmp;
+		dtmp = exp((2.*DOT(np->prdir,ldir)-2.)/dtmp)/(4.*PI*dtmp);
 						/* worth using? */
 		if (dtmp > FTINY) {
 			copycolor(ctmp, np->mcolor);
-			dtmp *= np->tspec * omega / np->pdot;
+			dtmp *= np->tspec * omega * sqrt(-ldot/np->pdot);
 			scalecolor(ctmp, dtmp);
 			addcolor(cval, ctmp);
 		}
@@ -158,6 +165,7 @@ register RAY  *r;
 	if (m->oargs.nfargs != (m->otype == MAT_TRANS ? 7 : 5))
 		objerror(m, USER, "bad number of arguments");
 	nd.mp = m;
+	nd.rp = r;
 						/* get material color */
 	setcolor(nd.mcolor, m->oargs.farg[0],
 			   m->oargs.farg[1],
@@ -186,15 +194,16 @@ register RAY  *r;
 		else
 			setcolor(nd.scolor, 1.0, 1.0, 1.0);
 		scalecolor(nd.scolor, nd.rspec);
-		if (nd.specfl & SP_PURE) {		/* improved model */
-			dtmp = exp(-BSPEC(m)*nd.pdot);
-			for (i = 0; i < 3; i++)
-				colval(nd.scolor,i) +=
-						(1.0-colval(nd.scolor,i))*dtmp;
-			nd.rspec += (1.0-nd.rspec)*dtmp;
-		} else if (specthresh > FTINY &&	/* check threshold */
+						/* improved model */
+		dtmp = exp(-BSPEC(m)*nd.pdot);
+		for (i = 0; i < 3; i++)
+			colval(nd.scolor,i) += (1.0-colval(nd.scolor,i))*dtmp;
+		nd.rspec += (1.0-nd.rspec)*dtmp;
+						/* check threshold */
+		if (!(nd.specfl & SP_PURE) &&
+				specthresh > FTINY &&
 				(specthresh >= 1.-FTINY ||
-				specthresh > nd.rspec))
+				specthresh + .05 - .1*frandom() > nd.rspec))
 			nd.specfl |= SP_RBLT;
 						/* compute reflected ray */
 		for (i = 0; i < 3; i++)
@@ -223,7 +232,7 @@ register RAY  *r;
 							/* check threshold */
 			if (!(nd.specfl & SP_PURE) && specthresh > FTINY &&
 					(specthresh >= 1.-FTINY ||
-					specthresh > nd.tspec))
+				specthresh + .05 - .1*frandom() > nd.tspec))
 				nd.specfl |= SP_TBLT;
 			if (r->crtype & SHADOW ||
 					DOT(r->pert,r->pert) <= FTINY*FTINY) {
@@ -231,8 +240,7 @@ register RAY  *r;
 				transtest = 2;
 			} else {
 				for (i = 0; i < 3; i++)		/* perturb */
-					nd.prdir[i] = r->rdir[i] -
-							0.5*r->pert[i];
+					nd.prdir[i] = r->rdir[i] - r->pert[i];
 				if (DOT(nd.prdir, r->ron) < -FTINY)
 					normalize(nd.prdir);	/* OK */
 				else
@@ -361,7 +369,7 @@ register NORMDAT  *np;
 		if (rv[1] <= FTINY)
 			d = 1.0;
 		else
-			d = sqrt( np->alpha2/4.0 * -log(rv[1]) );
+			d = sqrt( -log(rv[1]) * np->alpha2 );
 		for (i = 0; i < 3; i++)
 			sr.rdir[i] = np->prdir[i] + d*(cosp*u[i] + sinp*v[i]);
 		if (DOT(sr.rdir, r->ron) < -FTINY)