--- ray/src/rt/aniso.c	2004/09/20 17:32:04	2.42
+++ ray/src/rt/aniso.c	2010/10/01 18:11:18	2.46
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: aniso.c,v 2.42 2004/09/20 17:32:04 greg Exp $";
+static const char RCSid[] = "$Id: aniso.c,v 2.46 2010/10/01 18:11:18 greg Exp $";
 #endif
 /*
  *  Shading functions for anisotropic materials.
@@ -101,7 +101,7 @@ diraniso(		/* compute source contribution */
 	if (ldot > FTINY && (np->specfl&(SP_REFL|SP_BADU)) == SP_REFL) {
 		/*
 		 *  Compute specular reflection coefficient using
-		 *  anisotropic gaussian distribution model.
+		 *  anisotropic Gaussian distribution model.
 		 */
 						/* add source width if flat */
 		if (np->specfl & SP_FLAT)
@@ -119,14 +119,16 @@ diraniso(		/* compute source contribution */
 		dtmp1 *= dtmp1 / au2;
 		dtmp2 = DOT(np->v, h);
 		dtmp2 *= dtmp2 / av2;
-						/* gaussian */
+						/* new W-G-M-D model */
 		dtmp = DOT(np->pnorm, h);
-		dtmp = (dtmp1 + dtmp2) / (dtmp*dtmp);
-		dtmp = exp(-dtmp) / (4.0*PI * np->pdot * sqrt(au2*av2));
+		dtmp *= dtmp;
+		dtmp1 = (dtmp1 + dtmp2) / dtmp;
+		dtmp = exp(-dtmp1) * DOT(h,h) /
+				(PI * dtmp*dtmp * sqrt(au2*av2));
 						/* worth using? */
 		if (dtmp > FTINY) {
 			copycolor(ctmp, np->scolor);
-			dtmp *= omega;
+			dtmp *= ldot * omega;
 			scalecolor(ctmp, dtmp);
 			addcolor(cval, ctmp);
 		}
@@ -166,8 +168,8 @@ diraniso(		/* compute source contribution */
 			}
 		} else
 			dtmp = 0.0;
-						/* gaussian */
-		dtmp = exp(-dtmp) / (PI * np->pdot * sqrt(au2*av2));
+						/* Gaussian */
+		dtmp = exp(-dtmp) * (1.0/PI) * sqrt(-ldot/(np->pdot*au2*av2));
 						/* worth using? */
 		if (dtmp > FTINY) {
 			copycolor(ctmp, np->mcolor);
@@ -214,7 +216,7 @@ m_aniso(			/* shade ray that hit something anisotropic
 	nd.specfl = 0;
 	nd.u_alpha = m->oargs.farg[4];
 	nd.v_alpha = m->oargs.farg[5];
-	if (nd.u_alpha < FTINY || nd.v_alpha <= FTINY)
+	if (nd.u_alpha <= FTINY || nd.v_alpha <= FTINY)
 		objerror(m, USER, "roughness too small");
 
 	nd.pdot = raynormal(nd.pnorm, r);	/* perturb normal */
@@ -276,12 +278,12 @@ m_aniso(			/* shade ray that hit something anisotropic
 		agaussamp(r, &nd);
 
 	if (nd.rdiff > FTINY) {		/* ambient from this side */
-		ambient(ctmp, r, nd.pnorm);
+		copycolor(ctmp, nd.mcolor);	/* modified by material color */
 		if (nd.specfl & SP_RBLT)
 			scalecolor(ctmp, 1.0-nd.trans);
 		else
 			scalecolor(ctmp, nd.rdiff);
-		multcolor(ctmp, nd.mcolor);	/* modified by material color */
+		multambient(ctmp, r, nd.pnorm);
 		addcolor(r->rcol, ctmp);	/* add to returned color */
 	}
 	if (nd.tdiff > FTINY) {		/* ambient from other side */
@@ -291,12 +293,12 @@ m_aniso(			/* shade ray that hit something anisotropic
 		bnorm[0] = -nd.pnorm[0];
 		bnorm[1] = -nd.pnorm[1];
 		bnorm[2] = -nd.pnorm[2];
-		ambient(ctmp, r, bnorm);
+		copycolor(ctmp, nd.mcolor);	/* modified by color */
 		if (nd.specfl & SP_TBLT)
 			scalecolor(ctmp, nd.trans);
 		else
 			scalecolor(ctmp, nd.tdiff);
-		multcolor(ctmp, nd.mcolor);	/* modified by color */
+		multambient(ctmp, r, bnorm);
 		addcolor(r->rcol, ctmp);
 		flipsurface(r);
 	}
@@ -339,7 +341,7 @@ getacoords(		/* set up coordinate system */
 
 
 static void
-agaussamp(		/* sample anisotropic gaussian specular */
+agaussamp(		/* sample anisotropic Gaussian specular */
 	RAY  *r,
 	register ANISODAT  *np
 )
@@ -352,7 +354,7 @@ agaussamp(		/* sample anisotropic gaussian specular */
 	register int  i;
 					/* compute reflection */
 	if ((np->specfl & (SP_REFL|SP_RBLT)) == SP_REFL &&
-			rayorigin(&sr, r, SPECULAR, np->rspec) == 0) {
+			rayorigin(&sr, SPECULAR, r, np->scolor) == 0) {
 		dimlist[ndims++] = (int)np->mp;
 		for (niter = 0; niter < MAXITER; niter++) {
 			if (niter)
@@ -380,8 +382,9 @@ agaussamp(		/* sample anisotropic gaussian specular */
 			for (i = 0; i < 3; i++)
 				sr.rdir[i] = r->rdir[i] + d*h[i];
 			if (DOT(sr.rdir, r->ron) > FTINY) {
+				checknorm(sr.rdir);
 				rayvalue(&sr);
-				multcolor(sr.rcol, np->scolor);
+				multcolor(sr.rcol, sr.rcoef);
 				addcolor(r->rcol, sr.rcol);
 				break;
 			}
@@ -389,8 +392,10 @@ agaussamp(		/* sample anisotropic gaussian specular */
 		ndims--;
 	}
 					/* compute transmission */
+	copycolor(sr.rcoef, np->mcolor);		/* modify by material color */
+	scalecolor(sr.rcoef, np->tspec);
 	if ((np->specfl & (SP_TRAN|SP_TBLT)) == SP_TRAN &&
-			rayorigin(&sr, r, SPECULAR, np->tspec) == 0) {
+			rayorigin(&sr, SPECULAR, r, sr.rcoef) == 0) {
 		dimlist[ndims++] = (int)np->mp;
 		for (niter = 0; niter < MAXITER; niter++) {
 			if (niter)
@@ -417,8 +422,7 @@ agaussamp(		/* sample anisotropic gaussian specular */
 			if (DOT(sr.rdir, r->ron) < -FTINY) {
 				normalize(sr.rdir);	/* OK, normalize */
 				rayvalue(&sr);
-				scalecolor(sr.rcol, np->tspec);
-				multcolor(sr.rcol, np->mcolor);	/* modify */
+				multcolor(sr.rcol, sr.rcoef);
 				addcolor(r->rcol, sr.rcol);
 				break;
 			}