--- ray/src/rt/aniso.c	2012/06/09 07:16:47	2.53
+++ ray/src/rt/aniso.c	2024/12/06 01:34:21	2.66
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: aniso.c,v 2.53 2012/06/09 07:16:47 greg Exp $";
+static const char RCSid[] = "$Id: aniso.c,v 2.66 2024/12/06 01:34:21 greg Exp $";
 #endif
 /*
  *  Shading functions for anisotropic materials.
@@ -14,6 +14,7 @@ static const char RCSid[] = "$Id: aniso.c,v 2.53 2012/
 #include  "source.h"
 #include  "func.h"
 #include  "random.h"
+#include  "pmapmat.h"
 
 #ifndef  MAXITER
 #define  MAXITER	10		/* maximum # specular ray attempts */
@@ -21,14 +22,15 @@ static const char RCSid[] = "$Id: aniso.c,v 2.53 2012/
 
 /*
  *	This routine implements the anisotropic Gaussian
- *  model described by Ward in Siggraph `92 article.
+ *  model described by Ward in Siggraph `92 article, updated with
+ *  normalization and sampling adjustments due to Geisler-Moroder and Duer.
  *	We orient the surface towards the incoming ray, so a single
  *  surface can be used to represent an infinitely thin object.
  *
  *  Arguments for MAT_PLASTIC2 and MAT_METAL2 are:
  *  4+ ux	uy	uz	funcfile	[transform...]
  *  0
- *  6  red	grn	blu	specular-frac.	u-facet-slope v-facet-slope
+ *  6  red	grn	blu	specular-frac.	u-rough v-rough
  *
  *  Real arguments for MAT_TRANS2 are:
  *  8  red 	grn	blu	rspec	u-rough	v-rough	trans	tspec
@@ -40,15 +42,13 @@ static const char RCSid[] = "$Id: aniso.c,v 2.53 2012/
 #define  SP_FLAT	04		/* reflecting surface is flat */
 #define  SP_RBLT	010		/* reflection below sample threshold */
 #define  SP_TBLT	020		/* transmission below threshold */
-#define  SP_BADU	040		/* bad u direction calculation */
 
 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 */
-	FVECT  vrefl;		/* vector in reflected direction */
+	SCOLOR  mcolor;		/* color of this material */
+	SCOLOR  scolor;		/* color of specular component */
 	FVECT  prdir;		/* vector in transmitted direction */
 	FVECT  u, v;		/* u and v vectors orienting anisotropy */
 	double  u_alpha;	/* u roughness */
@@ -60,46 +60,59 @@ typedef struct {
 	double  pdot;		/* perturbed dot product */
 }  ANISODAT;		/* anisotropic material data */
 
-static srcdirf_t diraniso;
-static void getacoords(RAY  *r, ANISODAT  *np);
-static void agaussamp(RAY  *r, ANISODAT  *np);
+static void getacoords(ANISODAT  *np);
+static void agaussamp(ANISODAT  *np);
 
 
 static void
 diraniso(		/* compute source contribution */
-	COLOR  cval,			/* returned coefficient */
-	void  *nnp,		/* material data */
+	SCOLOR  scval,			/* returned coefficient */
+	void  *nnp,			/* material data */
 	FVECT  ldir,			/* light source direction */
 	double  omega			/* light source size */
 )
 {
-	register ANISODAT *np = nnp;
+	ANISODAT *np = nnp;
 	double  ldot;
 	double  dtmp, dtmp1, dtmp2;
 	FVECT  h;
 	double  au2, av2;
-	COLOR  ctmp;
+	SCOLOR  sctmp;
 
-	setcolor(cval, 0.0, 0.0, 0.0);
+	scolorblack(scval);
 
 	ldot = DOT(np->pnorm, ldir);
 
 	if (ldot < 0.0 ? np->trans <= FTINY : np->trans >= 1.0-FTINY)
 		return;		/* wrong side */
 
-	if (ldot > FTINY && np->rdiff > FTINY) {
+	if ((ldot > FTINY) & (np->rdiff > 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);
+		copyscolor(sctmp, np->mcolor);
 		dtmp = ldot * omega * np->rdiff * (1.0/PI);
-		scalecolor(ctmp, dtmp);
-		addcolor(cval, ctmp);
+		scalescolor(sctmp, dtmp);
+		saddscolor(scval, sctmp);
 	}
-	if (ldot > FTINY && (np->specfl&(SP_REFL|SP_BADU)) == SP_REFL) {
+
+	if ((ldot < -FTINY) & (np->tdiff > FTINY)) {
 		/*
+		 *  Compute diffuse transmission.
+		 */
+		copyscolor(sctmp, np->mcolor);
+		dtmp = -ldot * omega * np->tdiff * (1.0/PI);
+		scalescolor(sctmp, dtmp);
+		saddscolor(scval, sctmp);
+	}
+	
+	if (ambRayInPmap(np->rp))
+		return;		/* specular accounted for in photon map */
+
+	if (ldot > FTINY && np->specfl&SP_REFL) {
+		/*
 		 *  Compute specular reflection coefficient using
 		 *  anisotropic Gaussian distribution model.
 		 */
@@ -111,9 +124,7 @@ diraniso(		/* compute source contribution */
 		au2 += np->u_alpha*np->u_alpha;
 		av2 += np->v_alpha*np->v_alpha;
 						/* half vector */
-		h[0] = ldir[0] - np->rp->rdir[0];
-		h[1] = ldir[1] - np->rp->rdir[1];
-		h[2] = ldir[2] - np->rp->rdir[2];
+		VSUB(h, ldir, np->rp->rdir);
 						/* ellipse */
 		dtmp1 = DOT(np->u, h);
 		dtmp1 *= dtmp1 / au2;
@@ -127,23 +138,15 @@ diraniso(		/* compute source contribution */
 				(PI * dtmp*dtmp * sqrt(au2*av2));
 						/* worth using? */
 		if (dtmp > FTINY) {
-			copycolor(ctmp, np->scolor);
+			copyscolor(sctmp, np->scolor);
 			dtmp *= ldot * omega;
-			scalecolor(ctmp, dtmp);
-			addcolor(cval, ctmp);
+			scalescolor(sctmp, dtmp);
+			saddscolor(scval, sctmp);
 		}
 	}
-	if (ldot < -FTINY && np->tdiff > FTINY) {
+	
+	if (ldot < -FTINY && np->specfl&SP_TRAN) {
 		/*
-		 *  Compute diffuse transmission.
-		 */
-		copycolor(ctmp, np->mcolor);
-		dtmp = -ldot * omega * np->tdiff * (1.0/PI);
-		scalecolor(ctmp, dtmp);
-		addcolor(cval, ctmp);
-	}
-	if (ldot < -FTINY && (np->specfl&(SP_TRAN|SP_BADU)) == SP_TRAN) {
-		/*
 		 *  Compute specular transmission.  Specular transmission
 		 *  is always modified by material color.
 		 */
@@ -152,44 +155,43 @@ diraniso(		/* compute source contribution */
 		au2 += np->u_alpha*np->u_alpha;
 		av2 += np->v_alpha*np->v_alpha;
 						/* "half vector" */
-		h[0] = ldir[0] - np->prdir[0];
-		h[1] = ldir[1] - np->prdir[1];
-		h[2] = ldir[2] - np->prdir[2];
+		VSUB(h, ldir, np->prdir);
 		dtmp = DOT(h,h);
 		if (dtmp > FTINY*FTINY) {
 			dtmp1 = DOT(h,np->pnorm);
 			dtmp = 1.0 - dtmp1*dtmp1/dtmp;
-			if (dtmp > FTINY*FTINY) {
-				dtmp1 = DOT(h,np->u);
-				dtmp1 *= dtmp1 / au2;
-				dtmp2 = DOT(h,np->v);
-				dtmp2 *= dtmp2 / av2;
-				dtmp = (dtmp1 + dtmp2) / dtmp;
-			}
+		}
+		if (dtmp > FTINY*FTINY) {
+			dtmp1 = DOT(h,np->u);
+			dtmp1 *= dtmp1 / au2;
+			dtmp2 = DOT(h,np->v);
+			dtmp2 *= dtmp2 / av2;
+			dtmp = (dtmp1 + dtmp2) / dtmp;
+			dtmp = exp(-dtmp);
 		} else
-			dtmp = 0.0;
+			dtmp = 1.0;
 						/* Gaussian */
-		dtmp = exp(-dtmp) * (1.0/PI) * sqrt(-ldot/(np->pdot*au2*av2));
+		dtmp *= (1.0/PI) * sqrt(-ldot/(np->pdot*au2*av2));
 						/* worth using? */
 		if (dtmp > FTINY) {
-			copycolor(ctmp, np->mcolor);
+			copyscolor(sctmp, np->mcolor);
 			dtmp *= np->tspec * omega;
-			scalecolor(ctmp, dtmp);
-			addcolor(cval, ctmp);
+			scalescolor(sctmp, dtmp);
+			saddscolor(scval, sctmp);
 		}
 	}
 }
 
 
-extern int
+int
 m_aniso(			/* shade ray that hit something anisotropic */
-	register OBJREC  *m,
-	register RAY  *r
+	OBJREC  *m,
+	RAY  *r
 )
 {
 	ANISODAT  nd;
-	COLOR  ctmp;
-	register int  i;
+	SCOLOR  sctmp;
+	int  i;
 						/* easy shadow test */
 	if (r->crtype & SHADOW)
 		return(1);
@@ -198,7 +200,7 @@ m_aniso(			/* shade ray that hit something anisotropic
 		objerror(m, USER, "bad number of real arguments");
 						/* check for back side */
 	if (r->rod < 0.0) {
-		if (!backvis && m->otype != MAT_TRANS2) {
+		if (!backvis) {
 			raytrans(r);
 			return(1);
 		}
@@ -209,36 +211,32 @@ m_aniso(			/* shade ray that hit something anisotropic
 						/* get material color */
 	nd.mp = m;
 	nd.rp = r;
-	setcolor(nd.mcolor, m->oargs.farg[0],
+	setscolor(nd.mcolor, m->oargs.farg[0],
 			   m->oargs.farg[1],
 			   m->oargs.farg[2]);
 						/* get roughness */
 	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 */
 	if (nd.pdot < .001)
 		nd.pdot = .001;			/* non-zero for diraniso() */
-	multcolor(nd.mcolor, r->pcol);		/* modify material color */
+	smultscolor(nd.mcolor, r->pcol);	/* modify material color */
 						/* get specular component */
 	if ((nd.rspec = m->oargs.farg[3]) > FTINY) {
 		nd.specfl |= SP_REFL;
 						/* compute specular color */
 		if (m->otype == MAT_METAL2)
-			copycolor(nd.scolor, nd.mcolor);
+			copyscolor(nd.scolor, nd.mcolor);
 		else
-			setcolor(nd.scolor, 1.0, 1.0, 1.0);
-		scalecolor(nd.scolor, nd.rspec);
+			setscolor(nd.scolor, 1.0, 1.0, 1.0);
+		scalescolor(nd.scolor, nd.rspec);
 						/* check threshold */
 		if (specthresh >= nd.rspec-FTINY)
 			nd.specfl |= SP_RBLT;
-						/* compute refl. direction */
-		VSUM(nd.vrefl, r->rdir, nd.pnorm, 2.0*nd.pdot);
-		if (DOT(nd.vrefl, r->ron) <= FTINY)	/* penetration? */
-			VSUM(nd.vrefl, r->rdir, r->ron, 2.0*r->rod);
 	}
 						/* compute transmission */
 	if (m->otype == MAT_TRANS2) {
@@ -270,34 +268,33 @@ m_aniso(			/* shade ray that hit something anisotropic
 	if (r->ro != NULL && isflat(r->ro->otype))
 		nd.specfl |= SP_FLAT;
 
-	getacoords(r, &nd);			/* set up coordinates */
+	getacoords(&nd);			/* set up coordinates */
 
-	if (nd.specfl & (SP_REFL|SP_TRAN) && !(nd.specfl & SP_BADU))
-		agaussamp(r, &nd);
+	if (nd.specfl & (SP_REFL|SP_TRAN))
+		agaussamp(&nd);
 
 	if (nd.rdiff > FTINY) {		/* ambient from this side */
-		copycolor(ctmp, nd.mcolor);	/* modified by material color */
-		scalecolor(ctmp, nd.rdiff);
+		copyscolor(sctmp, nd.mcolor);	/* modified by material color */
+		scalescolor(sctmp, nd.rdiff);
 		if (nd.specfl & SP_RBLT)	/* add in specular as well? */
-			addcolor(ctmp, nd.scolor);
-		multambient(ctmp, r, nd.pnorm);
-		addcolor(r->rcol, ctmp);	/* add to returned color */
+			saddscolor(sctmp, nd.scolor);
+		multambient(sctmp, r, nd.pnorm);
+		saddscolor(r->rcol, sctmp);	/* add to returned color */
 	}
+	
 	if (nd.tdiff > FTINY) {		/* ambient from other side */
 		FVECT  bnorm;
-
-		flipsurface(r);
 		bnorm[0] = -nd.pnorm[0];
 		bnorm[1] = -nd.pnorm[1];
 		bnorm[2] = -nd.pnorm[2];
-		copycolor(ctmp, nd.mcolor);	/* modified by color */
-		if (nd.specfl & SP_TBLT)
-			scalecolor(ctmp, nd.trans);
-		else
-			scalecolor(ctmp, nd.tdiff);
-		multambient(ctmp, r, bnorm);
-		addcolor(r->rcol, ctmp);
-		flipsurface(r);
+		copyscolor(sctmp, nd.mcolor);	/* modified by color */
+		if (nd.specfl & SP_TBLT) {
+			scalescolor(sctmp, nd.trans);
+		} else {
+			scalescolor(sctmp, nd.tdiff);
+		}
+		multambient(sctmp, r, bnorm);
+		saddscolor(r->rcol, sctmp);
 	}
 					/* add direct component */
 	direct(r, diraniso, &nd);
@@ -305,71 +302,68 @@ m_aniso(			/* shade ray that hit something anisotropic
 	return(1);
 }
 
-
 static void
 getacoords(		/* set up coordinate system */
-	RAY  *r,
-	register ANISODAT  *np
+	ANISODAT  *np
 )
 {
-	register MFUNC  *mf;
-	register int  i;
+	MFUNC  *mf;
+	int  i;
 
 	mf = getfunc(np->mp, 3, 0x7, 1);
-	setfunc(np->mp, r);
+	setfunc(np->mp, np->rp);
 	errno = 0;
 	for (i = 0; i < 3; i++)
 		np->u[i] = evalue(mf->ep[i]);
-	if (errno == EDOM || errno == ERANGE) {
-		objerror(np->mp, WARNING, "compute error");
-		np->specfl |= SP_BADU;
-		return;
-	}
-	if (mf->fxp != &unitxf)
+	if ((errno == EDOM) | (errno == ERANGE))
+		np->u[0] = np->u[1] = np->u[2] = 0.0;
+	else if (mf->fxp != &unitxf)
 		multv3(np->u, np->u, mf->fxp->xfm);
 	fcross(np->v, np->pnorm, np->u);
 	if (normalize(np->v) == 0.0) {
-		objerror(np->mp, WARNING, "illegal orientation vector");
-		np->specfl |= SP_BADU;
-		return;
-	}
-	fcross(np->u, np->v, np->pnorm);
+		if (fabs(np->u_alpha - np->v_alpha) > 0.001)
+			objerror(np->mp, WARNING, "illegal orientation vector");
+		getperpendicular(np->u, np->pnorm, 1);	/* punting */
+		fcross(np->v, np->pnorm, np->u);
+		np->u_alpha = np->v_alpha = sqrt( 0.5 *
+			(np->u_alpha*np->u_alpha + np->v_alpha*np->v_alpha) );
+	} else
+		fcross(np->u, np->v, np->pnorm);
 }
 
 
 static void
 agaussamp(		/* sample anisotropic Gaussian specular */
-	RAY  *r,
-	register ANISODAT  *np
+	ANISODAT  *np
 )
 {
 	RAY  sr;
 	FVECT  h;
 	double  rv[2];
 	double  d, sinp, cosp;
-	COLOR	scol;
 	int  maxiter, ntrials, nstarget, nstaken;
-	register int  i;
+	int  i;
 					/* compute reflection */
 	if ((np->specfl & (SP_REFL|SP_RBLT)) == SP_REFL &&
-			rayorigin(&sr, SPECULAR, r, np->scolor) == 0) {
+			rayorigin(&sr, RSPECULAR, np->rp, np->scolor) == 0) {
+		SCOLOR	scol;
 		nstarget = 1;
 		if (specjitter > 1.5) {	/* multiple samples? */
-			nstarget = specjitter*r->rweight + .5;
+			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);
+				scalescolor(sr.rcoef, d);
 				sr.rweight *= d;
 			} else
 				nstarget = 1;
 		}
-		setcolor(scol, 0., 0., 0.);
+		scolorblack(scol);
 		dimlist[ndims++] = (int)(size_t)np->mp;
 		maxiter = MAXITER*nstarget;
-		for (nstaken = ntrials = 0; nstaken < nstarget &&
-						ntrials < maxiter; ntrials++) {
+		for (nstaken = ntrials = 0; (nstaken < nstarget) &
+						(ntrials < maxiter); ntrials++) {
 			if (ntrials)
 				d = frandom();
 			else
@@ -383,63 +377,60 @@ agaussamp(		/* sample anisotropic Gaussian specular */
 			sinp *= d;
 			if ((0. <= specjitter) & (specjitter < 1.))
 				rv[1] = 1.0 - specjitter*rv[1];
-			if (rv[1] <= FTINY)
-				d = 1.0;
-			else
-				d = sqrt(-log(rv[1]) /
+			d = (rv[1] <= FTINY) ? 1.0 : sqrt( -log(rv[1]) /
 					(cosp*cosp/(np->u_alpha*np->u_alpha) +
-					 sinp*sinp/(np->v_alpha*np->v_alpha)));
+					 sinp*sinp/(np->v_alpha*np->v_alpha)) );
 			for (i = 0; i < 3; i++)
 				h[i] = np->pnorm[i] +
 					d*(cosp*np->u[i] + sinp*np->v[i]);
-			d = -2.0 * DOT(h, r->rdir) / (1.0 + d*d);
-			VSUM(sr.rdir, r->rdir, h, d);
+			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, r->ron)) <= FTINY)
+			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. + r->rod/d);
-				scalecolor(sr.rcol, d);
-				addcolor(scol, sr.rcol);
+				d = 2./(1. + np->rp->rod/d);
+				scalescolor(sr.rcol, d);
+				saddscolor(scol, sr.rcol);
 			} else {
 				rayvalue(&sr);
-				multcolor(sr.rcol, sr.rcoef);
-				addcolor(r->rcol, sr.rcol);
+				smultscolor(sr.rcol, sr.rcoef);
+				saddscolor(np->rp->rcol, sr.rcol);
 			}
 			++nstaken;
 		}
 		if (nstarget > 1) {		/* final W-G-M-D weighting */
-			multcolor(scol, sr.rcoef);
+			smultscolor(scol, sr.rcoef);
 			d = (double)nstarget/ntrials;
-			scalecolor(scol, d);
-			addcolor(r->rcol, scol);
+			scalescolor(scol, d);
+			saddscolor(np->rp->rcol, scol);
 		}
 		ndims--;
 	}
 					/* compute transmission */
-	copycolor(sr.rcoef, np->mcolor);		/* modify by material color */
-	scalecolor(sr.rcoef, np->tspec);
+	copyscolor(sr.rcoef, np->mcolor);		/* modify by material color */
+	scalescolor(sr.rcoef, np->tspec);
 	if ((np->specfl & (SP_TRAN|SP_TBLT)) == SP_TRAN &&
-			rayorigin(&sr, SPECULAR, r, sr.rcoef) == 0) {
+			rayorigin(&sr, TSPECULAR, np->rp, sr.rcoef) == 0) {
 		nstarget = 1;
 		if (specjitter > 1.5) {	/* multiple samples? */
-			nstarget = specjitter*r->rweight + .5;
+			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);
+				scalescolor(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++) {
+		for (nstaken = ntrials = 0; (nstaken < nstarget) &
+						(ntrials < maxiter); ntrials++) {
 			if (ntrials)
 				d = frandom();
 			else
@@ -462,14 +453,14 @@ agaussamp(		/* sample anisotropic Gaussian specular */
 			for (i = 0; i < 3; i++)
 				sr.rdir[i] = np->prdir[i] +
 						d*(cosp*np->u[i] + sinp*np->v[i]);
-			if (DOT(sr.rdir, r->ron) >= -FTINY)
-				continue;
+			if (DOT(sr.rdir,np->rp->ron) >= -FTINY)
+				continue;	/* reject sample */
 			normalize(sr.rdir);	/* OK, normalize */
 			if (nstaken)		/* multi-sampling */
 				rayclear(&sr);
 			rayvalue(&sr);
-			multcolor(sr.rcol, sr.rcoef);
-			addcolor(r->rcol, sr.rcol);
+			smultscolor(sr.rcol, sr.rcoef);
+			saddscolor(np->rp->rcol, sr.rcol);
 			++nstaken;
 		}
 		ndims--;