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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 2.30 by greg, Mon Nov 6 12:03:20 1995 UTC

#	Line 19 | Line 19 | static char SCCSid[] = "$SunId$ LBL";
19		extern double  specthresh;              /* specular sampling threshold */
20		extern double  specjitter;              /* specular sampling jitter */
21
22	+	extern int  backvis;                    /* back faces visible? */
23	+
24	+	static  agaussamp(), getacoords();
25	+
26		/*
27	<	*      This anisotropic reflection model uses a variant on the
28	<	*  exponential Gaussian used in normal.c.
27	>	*      This routine implements the anisotropic Gaussian
28	>	*  model described by Ward in Siggraph `92 article.
29		*      We orient the surface towards the incoming ray, so a single
30		*  surface can be used to represent an infinitely thin object.
31		*
#	Line 34 | Line 38 | extern double  specjitter;             /* specular sampling jitte
38		*  8  red      grn     blu     rspec   u-rough v-rough trans   tspec
39		*/
40
37	–	#define  BSPEC(m)       (6.0)           /* specularity parameter b */
38	–
41		/* specularity flags */
42		#define  SP_REFL        01              /* has reflected specular component */
43		#define  SP_TRAN        02              /* has transmitted specular */
#	Line 70 | Line 72 | FVECT  ldir;                   /* light source direction */
72		double  omega;                  /* light source size */
73		{
74		double  ldot;
75	<	double  dtmp, dtmp2;
75	>	double  dtmp, dtmp1, dtmp2;
76		FVECT  h;
77		double  au2, av2;
78		COLOR  ctmp;
#	Line 103 | Line 105 | double  omega;                 /* light source size */
105		au2 = av2 = omega/(4.0*PI);
106		else
107		au2 = av2 = 0.0;
108	<	au2 += np->u_alpha * np->u_alpha;
109	<	av2 += np->v_alpha * np->v_alpha;
108	>	au2 += np->u_alpha*np->u_alpha;
109	>	av2 += np->v_alpha*np->v_alpha;
110		/* half vector */
111		h[0] = ldir[0] - np->rp->rdir[0];
112		h[1] = ldir[1] - np->rp->rdir[1];
113		h[2] = ldir[2] - np->rp->rdir[2];
112	–	normalize(h);
114		/* ellipse */
115	<	dtmp = DOT(np->u, h);
116	<	dtmp *= dtmp / au2;
115	>	dtmp1 = DOT(np->u, h);
116	>	dtmp1 *= dtmp1 / au2;
117		dtmp2 = DOT(np->v, h);
118		dtmp2 *= dtmp2 / av2;
119		/* gaussian */
120	<	dtmp = (dtmp + dtmp2) / (1.0 + DOT(np->pnorm, h));
121	<	dtmp = exp(-2.0*dtmp) / (4.0*PI * sqrt(au2*av2));
120	>	dtmp = DOT(np->pnorm, h);
121	>	dtmp = (dtmp1 + dtmp2) / (dtmp*dtmp);
122	>	dtmp = exp(-dtmp) * (0.25/PI)
123	>	* sqrt(ldot/(np->pdot*au2*av2));
124		/* worth using? */
125		if (dtmp > FTINY) {
126		copycolor(ctmp, np->scolor);
127	<	dtmp *= omega * sqrt(ldot/np->pdot);
127	>	dtmp *= omega;
128		scalecolor(ctmp, dtmp);
129		addcolor(cval, ctmp);
130		}
#	Line 141 | Line 144 | double  omega;                 /* light source size */
144		*  is always modified by material color.
145		*/
146		/* roughness + source */
147	+	au2 = av2 = omega / PI;
148	+	au2 += np->u_alpha*np->u_alpha;
149	+	av2 += np->v_alpha*np->v_alpha;
150	+	/* "half vector" */
151	+	h[0] = ldir[0] - np->prdir[0];
152	+	h[1] = ldir[1] - np->prdir[1];
153	+	h[2] = ldir[2] - np->prdir[2];
154	+	dtmp = DOT(h,h);
155	+	if (dtmp > FTINY*FTINY) {
156	+	dtmp1 = DOT(h,np->pnorm);
157	+	dtmp = 1.0 - dtmp1*dtmp1/dtmp;
158	+	if (dtmp > FTINY*FTINY) {
159	+	dtmp1 = DOT(h,np->u);
160	+	dtmp1 *= dtmp1 / au2;
161	+	dtmp2 = DOT(h,np->v);
162	+	dtmp2 *= dtmp2 / av2;
163	+	dtmp = (dtmp1 + dtmp2) / dtmp;
164	+	}
165	+	} else
166	+	dtmp = 0.0;
167		/* gaussian */
168	<	dtmp = 0.0;
168	>	dtmp = exp(-dtmp) * (1.0/PI)
169	>	* sqrt(-ldot/(np->pdot*au2*av2));
170		/* worth using? */
171		if (dtmp > FTINY) {
172		copycolor(ctmp, np->mcolor);
173	<	dtmp *= np->tspec * omega * sqrt(ldot/np->pdot);
173	>	dtmp *= np->tspec * omega;
174		scalecolor(ctmp, dtmp);
175		addcolor(cval, ctmp);
176		}
#	Line 159 | Line 183 | register OBJREC  *m;
183		register RAY  *r;
184		{
185		ANISODAT  nd;
162	–	double  dtmp;
186		COLOR  ctmp;
187		register int  i;
188		/* easy shadow test */
189		if (r->crtype & SHADOW)
190	<	return;
190	>	return(1);
191
192		if (m->oargs.nfargs != (m->otype == MAT_TRANS2 ? 8 : 6))
193		objerror(m, USER, "bad number of real arguments");
#	Line 178 | Line 201 | register RAY  *r;
201		nd.specfl = 0;
202		nd.u_alpha = m->oargs.farg[4];
203		nd.v_alpha = m->oargs.farg[5];
204	<	if (nd.u_alpha < 1e-6 || nd.v_alpha <= 1e-6)
204	>	if (nd.u_alpha < FTINY || nd.v_alpha <= FTINY)
205		objerror(m, USER, "roughness too small");
206	<	/* reorient if necessary */
207	<	if (r->rod < 0.0)
208	<	flipsurface(r);
206	>	/* check for back side */
207	>	if (r->rod < 0.0) {
208	>	if (!backvis && m->otype != MAT_TRANS2) {
209	>	raytrans(r);
210	>	return(1);
211	>	}
212	>	flipsurface(r);                 /* reorient if backvis */
213	>	}
214		/* get modifiers */
215		raytexture(r, m->omod);
216		nd.pdot = raynormal(nd.pnorm, r);       /* perturb normal */
#	Line 198 | Line 226 | register RAY  *r;
226		else
227		setcolor(nd.scolor, 1.0, 1.0, 1.0);
228		scalecolor(nd.scolor, nd.rspec);
201	–	/* improved model */
202	–	dtmp = exp(-BSPEC(m)*nd.pdot);
203	–	for (i = 0; i < 3; i++)
204	–	colval(nd.scolor,i) += (1.0-colval(nd.scolor,i))*dtmp;
205	–	nd.rspec += (1.0-nd.rspec)*dtmp;
229		/* check threshold */
230	<	if (specthresh > FTINY &&
208	<	(specthresh >= 1.-FTINY ||
209	<	specthresh + .05 - .1*frandom() > nd.rspec))
230	>	if (specthresh >= nd.rspec-FTINY)
231		nd.specfl |= SP_RBLT;
232		/* compute refl. direction */
233		for (i = 0; i < 3; i++)
#	Line 216 | Line 237 | register RAY  *r;
237		nd.vrefl[i] = r->rdir[i] + 2.*r->rod*r->ron[i];
238		}
239		/* compute transmission */
240	<	if (m->otype == MAT_TRANS) {
240	>	if (m->otype == MAT_TRANS2) {
241		nd.trans = m->oargs.farg[6]*(1.0 - nd.rspec);
242		nd.tspec = nd.trans * m->oargs.farg[7];
243		nd.tdiff = nd.trans - nd.tspec;
244		if (nd.tspec > FTINY) {
245		nd.specfl |= SP_TRAN;
246		/* check threshold */
247	<	if (specthresh > FTINY &&
227	<	(specthresh >= 1.-FTINY ||
228	<	specthresh + .05 - .1*frandom() > nd.tspec))
247	>	if (specthresh >= nd.tspec-FTINY)
248		nd.specfl |= SP_TBLT;
249		if (DOT(r->pert,r->pert) <= FTINY*FTINY) {
250		VCOPY(nd.prdir, r->rdir);
251		} else {
252		for (i = 0; i < 3; i++)         /* perturb */
253	<	nd.prdir[i] = r->rdir[i] -
235	<	0.5*r->pert[i];
253	>	nd.prdir[i] = r->rdir[i] - r->pert[i];
254		if (DOT(nd.prdir, r->ron) < -FTINY)
255		normalize(nd.prdir);    /* OK */
256		else
#	Line 245 | Line 263 | register RAY  *r;
263		/* diffuse reflection */
264		nd.rdiff = 1.0 - nd.trans - nd.rspec;
265
266	<	if (r->ro != NULL && (r->ro->otype == OBJ_FACE ||
249	<	r->ro->otype == OBJ_RING))
266	>	if (r->ro != NULL && isflat(r->ro->otype))
267		nd.specfl |= SP_FLAT;
268
269		getacoords(r, &nd);                     /* set up coordinates */
#	Line 255 | Line 272 | register RAY  *r;
272		agaussamp(r, &nd);
273
274		if (nd.rdiff > FTINY) {         /* ambient from this side */
275	<	ambient(ctmp, r);
275	>	ambient(ctmp, r, nd.pnorm);
276		if (nd.specfl & SP_RBLT)
277		scalecolor(ctmp, 1.0-nd.trans);
278		else
#	Line 265 | Line 282 | register RAY  *r;
282		}
283		if (nd.tdiff > FTINY) {         /* ambient from other side */
284		flipsurface(r);
285	<	ambient(ctmp, r);
285	>	ambient(ctmp, r, nd.pnorm);
286		if (nd.specfl & SP_TBLT)
287		scalecolor(ctmp, nd.trans);
288		else
#	Line 276 | Line 293 | register RAY  *r;
293		}
294		/* add direct component */
295		direct(r, diraniso, &nd);
296	+
297	+	return(1);
298		}
299
300
#	Line 297 | Line 316 | register ANISODAT  *np;
316		np->specfl |= SP_BADU;
317		return;
318		}
319	<	multv3(np->u, np->u, mf->f->xfm);
319	>	if (mf->f != &unitxf)
320	>	multv3(np->u, np->u, mf->f->xfm);
321		fcross(np->v, np->pnorm, np->u);
322		if (normalize(np->v) == 0.0) {
323		objerror(np->mp, WARNING, "illegal orientation vector");
#	Line 325 | Line 345 | register ANISODAT  *np;
345		d = urand(ilhash(dimlist,ndims)+samplendx);
346		multisamp(rv, 2, d);
347		d = 2.0*PI * rv[0];
348	<	cosp = np->u_alpha * cos(d);
349	<	sinp = np->v_alpha * sin(d);
348	>	cosp = cos(d) * np->u_alpha;
349	>	sinp = sin(d) * np->v_alpha;
350		d = sqrt(cosp*cosp + sinp*sinp);
351		cosp /= d;
352		sinp /= d;
#	Line 357 | Line 377 | register ANISODAT  *np;
377		d = urand(ilhash(dimlist,ndims)+1823+samplendx);
378		multisamp(rv, 2, d);
379		d = 2.0*PI * rv[0];
380	<	cosp = cos(d);
381	<	sinp = sin(d);
380	>	cosp = cos(d) * np->u_alpha;
381	>	sinp = sin(d) * np->v_alpha;
382	>	d = sqrt(cosp*cosp + sinp*sinp);
383	>	cosp /= d;
384	>	sinp /= d;
385		rv[1] = 1.0 - specjitter*rv[1];
386		if (rv[1] <= FTINY)
387		d = 1.0;
388		else
389		d = sqrt(-log(rv[1]) /
390	<	(cosp*cosp*4./(np->u_alpha*np->u_alpha) +
391	<	sinp*sinp*4./(np->v_alpha*np->v_alpha)));
390	>	(cosp*cosp/(np->u_alpha*np->u_alpha) +
391	>	sinp*sinp/(np->v_alpha*np->u_alpha)));
392		for (i = 0; i < 3; i++)
393		sr.rdir[i] = np->prdir[i] +
394		d*(cosp*np->u[i] + sinp*np->v[i]);

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