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Comparing ray/src/rt/aniso.c (file contents):
Revision 2.15 by greg, Thu May 14 11:32:09 1992 UTC vs.
Revision 2.23 by greg, Fri Feb 12 10:41:05 1993 UTC

#	Line 20 | Line 20 | extern double  specthresh;             /* specular sampling thres
20		extern double  specjitter;              /* specular sampling jitter */
21
22		/*
23	<	*      This anisotropic reflection model uses a variant on the
24	<	*  exponential Gaussian used in normal.c.
23	>	*      This routine implements the anisotropic Gaussian
24	>	*  model described by Ward in Siggraph `92 article.
25		*      We orient the surface towards the incoming ray, so a single
26		*  surface can be used to represent an infinitely thin object.
27		*
#	Line 70 | Line 70 | FVECT  ldir;                   /* light source direction */
70		double  omega;                  /* light source size */
71		{
72		double  ldot;
73	<	double  dtmp, dtmp2;
73	>	double  dtmp, dtmp1, dtmp2;
74		FVECT  h;
75		double  au2, av2;
76		COLOR  ctmp;
#	Line 103 | Line 103 | double  omega;                 /* light source size */
103		au2 = av2 = omega/(4.0*PI);
104		else
105		au2 = av2 = 0.0;
106	<	au2 += np->u_alpha * np->u_alpha;
107	<	av2 += np->v_alpha * np->v_alpha;
106	>	au2 += np->u_alpha*np->u_alpha;
107	>	av2 += np->v_alpha*np->v_alpha;
108		/* half vector */
109		h[0] = ldir[0] - np->rp->rdir[0];
110		h[1] = ldir[1] - np->rp->rdir[1];
111		h[2] = ldir[2] - np->rp->rdir[2];
112	–	normalize(h);
112		/* ellipse */
113	<	dtmp = DOT(np->u, h);
114	<	dtmp *= dtmp / au2;
113	>	dtmp1 = DOT(np->u, h);
114	>	dtmp1 *= dtmp1 / au2;
115		dtmp2 = DOT(np->v, h);
116		dtmp2 *= dtmp2 / av2;
117		/* gaussian */
118	<	dtmp = (dtmp + dtmp2) / (1.0 + DOT(np->pnorm, h));
119	<	dtmp = exp(-2.0*dtmp) / (4.0*PI * sqrt(au2*av2));
118	>	dtmp = DOT(np->pnorm, h);
119	>	dtmp = (dtmp1 + dtmp2) / (dtmp*dtmp);
120	>	dtmp = exp(-dtmp) * (0.25/PI)
121	>	* sqrt(ldot/(np->pdot*au2*av2));
122		/* worth using? */
123		if (dtmp > FTINY) {
124		copycolor(ctmp, np->scolor);
125	<	dtmp *= omega * sqrt(ldot/np->pdot);
125	>	dtmp *= omega;
126		scalecolor(ctmp, dtmp);
127		addcolor(cval, ctmp);
128		}
#	Line 141 | Line 142 | double  omega;                 /* light source size */
142		*  is always modified by material color.
143		*/
144		/* roughness + source */
145	+	au2 = av2 = omega / PI;
146	+	au2 += np->u_alpha*np->u_alpha;
147	+	av2 += np->v_alpha*np->v_alpha;
148	+	/* "half vector" */
149	+	h[0] = ldir[0] - np->prdir[0];
150	+	h[1] = ldir[1] - np->prdir[1];
151	+	h[2] = ldir[2] - np->prdir[2];
152	+	dtmp = DOT(h,h);
153	+	if (dtmp > FTINY*FTINY) {
154	+	dtmp1 = DOT(h,np->pnorm);
155	+	dtmp = 1.0 - dtmp1*dtmp1/dtmp;
156	+	if (dtmp > FTINY*FTINY) {
157	+	dtmp1 = DOT(h,np->u);
158	+	dtmp1 *= dtmp1 / au2;
159	+	dtmp2 = DOT(h,np->v);
160	+	dtmp2 *= dtmp2 / av2;
161	+	dtmp = (dtmp1 + dtmp2) / dtmp;
162	+	}
163	+	} else
164	+	dtmp = 0.0;
165		/* gaussian */
166	<	dtmp = 0.0;
166	>	dtmp = exp(-dtmp) * (1.0/PI)
167	>	* sqrt(-ldot/(np->pdot*au2*av2));
168		/* worth using? */
169		if (dtmp > FTINY) {
170		copycolor(ctmp, np->mcolor);
171	<	dtmp *= np->tspec * omega * sqrt(ldot/np->pdot);
171	>	dtmp *= np->tspec * omega;
172		scalecolor(ctmp, dtmp);
173		addcolor(cval, ctmp);
174		}
#	Line 178 | Line 200 | register RAY  *r;
200		nd.specfl = 0;
201		nd.u_alpha = m->oargs.farg[4];
202		nd.v_alpha = m->oargs.farg[5];
203	<	if (nd.u_alpha < 1e-6 || nd.v_alpha <= 1e-6)
203	>	if (nd.u_alpha < FTINY || nd.v_alpha <= FTINY)
204		objerror(m, USER, "roughness too small");
205		/* reorient if necessary */
206		if (r->rod < 0.0)
#	Line 216 | Line 238 | register RAY  *r;
238		nd.vrefl[i] = r->rdir[i] + 2.*r->rod*r->ron[i];
239		}
240		/* compute transmission */
241	<	if (m->otype == MAT_TRANS) {
241	>	if (m->otype == MAT_TRANS2) {
242		nd.trans = m->oargs.farg[6]*(1.0 - nd.rspec);
243		nd.tspec = nd.trans * m->oargs.farg[7];
244		nd.tdiff = nd.trans - nd.tspec;
#	Line 231 | Line 253 | register RAY  *r;
253		VCOPY(nd.prdir, r->rdir);
254		} else {
255		for (i = 0; i < 3; i++)         /* perturb */
256	<	nd.prdir[i] = r->rdir[i] -
235	<	0.5*r->pert[i];
256	>	nd.prdir[i] = r->rdir[i] - r->pert[i];
257		if (DOT(nd.prdir, r->ron) < -FTINY)
258		normalize(nd.prdir);    /* OK */
259		else
#	Line 297 | Line 318 | register ANISODAT  *np;
318		np->specfl |= SP_BADU;
319		return;
320		}
321	<	multv3(np->u, np->u, mf->f->xfm);
321	>	if (mf->f != &unitxf)
322	>	multv3(np->u, np->u, mf->f->xfm);
323		fcross(np->v, np->pnorm, np->u);
324		if (normalize(np->v) == 0.0) {
325		objerror(np->mp, WARNING, "illegal orientation vector");
#	Line 325 | Line 347 | register ANISODAT  *np;
347		d = urand(ilhash(dimlist,ndims)+samplendx);
348		multisamp(rv, 2, d);
349		d = 2.0*PI * rv[0];
350	<	cosp = np->u_alpha * cos(d);
351	<	sinp = np->v_alpha * sin(d);
350	>	cosp = cos(d) * np->u_alpha;
351	>	sinp = sin(d) * np->v_alpha;
352		d = sqrt(cosp*cosp + sinp*sinp);
353		cosp /= d;
354		sinp /= d;
#	Line 357 | Line 379 | register ANISODAT  *np;
379		d = urand(ilhash(dimlist,ndims)+1823+samplendx);
380		multisamp(rv, 2, d);
381		d = 2.0*PI * rv[0];
382	<	cosp = cos(d);
383	<	sinp = sin(d);
382	>	cosp = cos(d) * np->u_alpha;
383	>	sinp = sin(d) * np->v_alpha;
384	>	d = sqrt(cosp*cosp + sinp*sinp);
385	>	cosp /= d;
386	>	sinp /= d;
387		rv[1] = 1.0 - specjitter*rv[1];
388		if (rv[1] <= FTINY)
389		d = 1.0;
390		else
391		d = sqrt(-log(rv[1]) /
392	<	(cosp*cosp*4./(np->u_alpha*np->u_alpha) +
393	<	sinp*sinp*4./(np->v_alpha*np->v_alpha)));
392	>	(cosp*cosp/(np->u_alpha*np->u_alpha) +
393	>	sinp*sinp/(np->v_alpha*np->u_alpha)));
394		for (i = 0; i < 3; i++)
395		sr.rdir[i] = np->prdir[i] +
396		d*(cosp*np->u[i] + sinp*np->v[i]);

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