--- ray/src/rt/normal.c	2010/09/26 15:51:15	2.53
+++ ray/src/rt/normal.c	2012/08/01 15:26:36	2.65
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: normal.c,v 2.53 2010/09/26 15:51:15 greg Exp $";
+static const char RCSid[] = "$Id: normal.c,v 2.65 2012/08/01 15:26:36 greg Exp $";
 #endif
 /*
  *  normal.c - shading function for normal materials.
@@ -65,22 +65,21 @@ typedef struct {
 	double  pdot;		/* perturbed dot product */
 }  NORMDAT;		/* normal material data */
 
-static srcdirf_t dirnorm;
-static void gaussamp(RAY  *r, NORMDAT  *np);
+static void gaussamp(NORMDAT  *np);
 
 
 static void
 dirnorm(		/* compute source contribution */
 	COLOR  cval,			/* returned coefficient */
-	void  *nnp,		/* material data */
+	void  *nnp,			/* material data */
 	FVECT  ldir,			/* light source direction */
 	double  omega			/* light source size */
 )
 {
-	register NORMDAT *np = nnp;
+	NORMDAT *np = nnp;
 	double  ldot;
 	double  lrdiff, ltdiff;
-	double  dtmp, d2;
+	double  dtmp, d2, d3, d4;
 	FVECT  vtmp;
 	COLOR  ctmp;
 
@@ -115,7 +114,7 @@ dirnorm(		/* compute source contribution */
 	if (ldot > FTINY && (np->specfl&(SP_REFL|SP_PURE)) == SP_REFL) {
 		/*
 		 *  Compute specular reflection coefficient using
-		 *  gaussian distribution model.
+		 *  Gaussian distribution model.
 		 */
 						/* roughness */
 		dtmp = np->alpha2;
@@ -123,18 +122,17 @@ dirnorm(		/* compute source contribution */
 		if (np->specfl & SP_FLAT)
 			dtmp += omega * (0.25/PI);
 						/* half vector */
-		vtmp[0] = ldir[0] - np->rp->rdir[0];
-		vtmp[1] = ldir[1] - np->rp->rdir[1];
-		vtmp[2] = ldir[2] - np->rp->rdir[2];
+		VSUB(vtmp, ldir, np->rp->rdir);
 		d2 = DOT(vtmp, np->pnorm);
 		d2 *= d2;
-		d2 = (DOT(vtmp,vtmp) - d2) / d2;
-						/* gaussian */
-		dtmp = exp(-d2/dtmp)/(4.*PI * np->pdot * dtmp);
+		d3 = DOT(vtmp,vtmp);
+		d4 = (d3 - d2) / d2;
+						/* new W-G-M-D model */
+		dtmp = exp(-d4/dtmp) * d3 / (PI * d2*d2 * dtmp);
 						/* worth using? */
 		if (dtmp > FTINY) {
 			copycolor(ctmp, np->scolor);
-			dtmp *= omega;
+			dtmp *= ldot * omega;
 			scalecolor(ctmp, dtmp);
 			addcolor(cval, ctmp);
 		}
@@ -155,7 +153,7 @@ dirnorm(		/* compute source contribution */
 		 */
 						/* roughness + source */
 		dtmp = np->alpha2 + omega*(1.0/PI);
-						/* gaussian */
+						/* Gaussian */
 		dtmp = exp((2.*DOT(np->prdir,ldir)-2.)/dtmp)/(PI*dtmp);
 						/* worth using? */
 		if (dtmp > FTINY) {
@@ -168,10 +166,10 @@ dirnorm(		/* compute source contribution */
 }
 
 
-extern int
+int
 m_normal(			/* color a ray that hit something normal */
-	register OBJREC  *m,
-	register RAY  *r
+	OBJREC  *m,
+	RAY  *r
 )
 {
 	NORMDAT  nd;
@@ -181,7 +179,7 @@ m_normal(			/* color a ray that hit something normal *
 	int	hastexture;
 	double	d;
 	COLOR  ctmp;
-	register int  i;
+	int  i;
 						/* easy shadow test */
 	if (r->crtype & SHADOW && m->otype != MAT_TRANS)
 		return(1);
@@ -226,7 +224,7 @@ m_normal(			/* color a ray that hit something normal *
 	nd.rspec = m->oargs.farg[3];
 						/* compute Fresnel approx. */
 	if (nd.specfl & SP_PURE && nd.rspec >= FRESTHRESH) {
-		fest = FRESNE(r->rod);
+		fest = FRESNE(nd.pdot);
 		nd.rspec += fest*(1. - nd.rspec);
 	} else
 		fest = 0.;
@@ -282,9 +280,10 @@ m_normal(			/* color a ray that hit something normal *
 		if (m->otype != MAT_METAL) {
 			setcolor(nd.scolor, nd.rspec, nd.rspec, nd.rspec);
 		} else if (fest > FTINY) {
-			d = nd.rspec*(1. - fest);
+			d = m->oargs.farg[3]*(1. - fest);
 			for (i = 0; i < 3; i++)
-				nd.scolor[i] = fest + nd.mcolor[i]*d;
+				colval(nd.scolor,i) = fest +
+						colval(nd.mcolor,i)*d;
 		} else {
 			copycolor(nd.scolor, nd.mcolor);
 			scalecolor(nd.scolor, nd.rspec);
@@ -293,12 +292,10 @@ m_normal(			/* color a ray that hit something normal *
 		if (!(nd.specfl & SP_PURE) && specthresh >= nd.rspec-FTINY)
 			nd.specfl |= SP_RBLT;
 						/* compute reflected ray */
-		for (i = 0; i < 3; i++)
-			nd.vrefl[i] = r->rdir[i] + 2.*nd.pdot*nd.pnorm[i];
+		VSUM(nd.vrefl, r->rdir, nd.pnorm, 2.*nd.pdot);
 						/* penetration? */
 		if (hastexture && DOT(nd.vrefl, r->ron) <= FTINY)
-			for (i = 0; i < 3; i++)		/* safety measure */
-				nd.vrefl[i] = r->rdir[i] + 2.*r->rod*r->ron[i];
+			VSUM(nd.vrefl, r->rdir, r->ron, 2.*r->rod);
 		checknorm(nd.vrefl);
 	}
 						/* reflected ray */
@@ -322,14 +319,13 @@ m_normal(			/* color a ray that hit something normal *
 		return(1);			/* 100% pure specular */
 
 	if (!(nd.specfl & SP_PURE))
-		gaussamp(r, &nd);		/* checks *BLT flags */
+		gaussamp(&nd);		/* checks *BLT flags */
 
 	if (nd.rdiff > FTINY) {		/* ambient from this side */
 		copycolor(ctmp, nd.mcolor);	/* modified by material color */
-		if (nd.specfl & SP_RBLT)
-			scalecolor(ctmp, 1.0-nd.trans);
-		else
-			scalecolor(ctmp, nd.rdiff);
+		scalecolor(ctmp, nd.rdiff);
+		if (nd.specfl & SP_RBLT)	/* add in specular as well? */
+			addcolor(ctmp, nd.scolor);
 		multambient(ctmp, r, hastexture ? nd.pnorm : r->ron);
 		addcolor(r->rcol, ctmp);	/* add to returned color */
 	}
@@ -365,17 +361,17 @@ m_normal(			/* color a ray that hit something normal *
 
 
 static void
-gaussamp(			/* sample gaussian specular */
-	RAY  *r,
-	register NORMDAT  *np
+gaussamp(			/* sample Gaussian specular */
+	NORMDAT  *np
 )
 {
 	RAY  sr;
 	FVECT  u, v, h;
 	double  rv[2];
 	double  d, sinp, cosp;
-	int  niter;
-	register int  i;
+	COLOR  scol;
+	int  maxiter, ntrials, nstarget, nstaken;
+	int  i;
 					/* quick test */
 	if ((np->specfl & (SP_REFL|SP_RBLT)) != SP_REFL &&
 			(np->specfl & (SP_TRAN|SP_TBLT)) != SP_TRAN)
@@ -391,10 +387,25 @@ gaussamp(			/* sample gaussian specular */
 	fcross(v, np->pnorm, u);
 					/* compute reflection */
 	if ((np->specfl & (SP_REFL|SP_RBLT)) == SP_REFL &&
-			rayorigin(&sr, SPECULAR, r, np->scolor) == 0) {
-		dimlist[ndims++] = (int)np->mp;
-		for (niter = 0; niter < MAXITER; niter++) {
-			if (niter)
+			rayorigin(&sr, SPECULAR, np->rp, np->scolor) == 0) {
+		nstarget = 1;
+		if (specjitter > 1.5) {	/* multiple samples? */
+			nstarget = specjitter*np->rp->rweight + .5;
+			if (sr.rweight <= minweight*nstarget)
+				nstarget = sr.rweight/minweight;
+			if (nstarget > 1) {
+				d = 1./nstarget;
+				scalecolor(sr.rcoef, d);
+				sr.rweight *= d;
+			} else
+				nstarget = 1;
+		}
+		setcolor(scol, 0., 0., 0.);
+		dimlist[ndims++] = (int)(size_t)np->mp;
+		maxiter = MAXITER*nstarget;
+		for (nstaken = ntrials = 0; nstaken < nstarget &&
+						ntrials < maxiter; ntrials++) {
+			if (ntrials)
 				d = frandom();
 			else
 				d = urand(ilhash(dimlist,ndims)+samplendx);
@@ -402,54 +413,88 @@ gaussamp(			/* sample gaussian specular */
 			d = 2.0*PI * rv[0];
 			cosp = tcos(d);
 			sinp = tsin(d);
-			rv[1] = 1.0 - specjitter*rv[1];
+			if ((0. <= specjitter) & (specjitter < 1.))
+				rv[1] = 1.0 - specjitter*rv[1];
 			if (rv[1] <= FTINY)
 				d = 1.0;
 			else
 				d = sqrt( np->alpha2 * -log(rv[1]) );
 			for (i = 0; i < 3; i++)
 				h[i] = np->pnorm[i] + d*(cosp*u[i] + sinp*v[i]);
-			d = -2.0 * DOT(h, r->rdir) / (1.0 + d*d);
-			for (i = 0; i < 3; i++)
-				sr.rdir[i] = r->rdir[i] + d*h[i];
-			if (DOT(sr.rdir, r->ron) > FTINY) {
+			d = -2.0 * DOT(h, np->rp->rdir) / (1.0 + d*d);
+			VSUM(sr.rdir, np->rp->rdir, h, d);
+						/* sample rejection test */
+			if ((d = DOT(sr.rdir, np->rp->ron)) <= FTINY)
+				continue;
+			checknorm(sr.rdir);
+			if (nstarget > 1) {	/* W-G-M-D adjustment */
+				if (nstaken) rayclear(&sr);
 				rayvalue(&sr);
+				d = 2./(1. + np->rp->rod/d);
+				scalecolor(sr.rcol, d);
+				addcolor(scol, sr.rcol);
+			} else {
+				rayvalue(&sr);
 				multcolor(sr.rcol, sr.rcoef);
-				addcolor(r->rcol, sr.rcol);
-				break;
+				addcolor(np->rp->rcol, sr.rcol);
 			}
+			++nstaken;
 		}
+		if (nstarget > 1) {		/* final W-G-M-D weighting */
+			multcolor(scol, sr.rcoef);
+			d = (double)nstarget/ntrials;
+			scalecolor(scol, d);
+			addcolor(np->rp->rcol, scol);
+		}
 		ndims--;
 	}
 					/* compute transmission */
 	copycolor(sr.rcoef, np->mcolor);	/* modified by color */
 	scalecolor(sr.rcoef, np->tspec);
 	if ((np->specfl & (SP_TRAN|SP_TBLT)) == SP_TRAN &&
-			rayorigin(&sr, SPECULAR, r, sr.rcoef) == 0) {
-		dimlist[ndims++] = (int)np->mp;
-		for (niter = 0; niter < MAXITER; niter++) {
-			if (niter)
+			rayorigin(&sr, SPECULAR, np->rp, sr.rcoef) == 0) {
+		nstarget = 1;
+		if (specjitter > 1.5) {	/* multiple samples? */
+			nstarget = specjitter*np->rp->rweight + .5;
+			if (sr.rweight <= minweight*nstarget)
+				nstarget = sr.rweight/minweight;
+			if (nstarget > 1) {
+				d = 1./nstarget;
+				scalecolor(sr.rcoef, d);
+				sr.rweight *= d;
+			} else
+				nstarget = 1;
+		}
+		dimlist[ndims++] = (int)(size_t)np->mp;
+		maxiter = MAXITER*nstarget;
+		for (nstaken = ntrials = 0; nstaken < nstarget &&
+						ntrials < maxiter; ntrials++) {
+			if (ntrials)
 				d = frandom();
 			else
-				d = urand(ilhash(dimlist,ndims)+1823+samplendx);
+				d = urand(ilhash(dimlist,ndims)+samplendx);
 			multisamp(rv, 2, d);
 			d = 2.0*PI * rv[0];
 			cosp = tcos(d);
 			sinp = tsin(d);
-			rv[1] = 1.0 - specjitter*rv[1];
+			if ((0. <= specjitter) & (specjitter < 1.))
+				rv[1] = 1.0 - specjitter*rv[1];
 			if (rv[1] <= FTINY)
 				d = 1.0;
 			else
 				d = sqrt( np->alpha2 * -log(rv[1]) );
 			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) {
-				normalize(sr.rdir);	/* OK, normalize */
-				rayvalue(&sr);
-				multcolor(sr.rcol, sr.rcoef);
-				addcolor(r->rcol, sr.rcol);
-				break;
-			}
+						/* sample rejection test */
+			if (DOT(sr.rdir, np->rp->ron) >= -FTINY)
+				continue;
+			normalize(sr.rdir);	/* OK, normalize */
+			if (nstaken)		/* multi-sampling */
+				rayclear(&sr);
+			rayvalue(&sr);
+			multcolor(sr.rcol, sr.rcoef);
+			addcolor(np->rp->rcol, sr.rcol);
+			++nstaken;
 		}
 		ndims--;
 	}