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 |
|
* |
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 */ |
44 |
< |
#define SP_PURE 010 /* purely specular (zero roughness) */ |
45 |
< |
#define SP_FLAT 020 /* reflecting surface is flat */ |
46 |
< |
#define SP_RBLT 040 /* reflection below sample threshold */ |
47 |
< |
#define SP_TBLT 0100 /* transmission below threshold */ |
46 |
< |
#define SP_BADU 0200 /* bad u direction calculation */ |
44 |
> |
#define SP_FLAT 04 /* reflecting surface is flat */ |
45 |
> |
#define SP_RBLT 010 /* reflection below sample threshold */ |
46 |
> |
#define SP_TBLT 020 /* transmission below threshold */ |
47 |
> |
#define SP_BADU 040 /* bad u direction calculation */ |
48 |
|
|
49 |
|
typedef struct { |
50 |
|
OBJREC *mp; /* material pointer */ |
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; |
95 |
|
scalecolor(ctmp, dtmp); |
96 |
|
addcolor(cval, ctmp); |
97 |
|
} |
98 |
< |
if (ldot > FTINY && (np->specfl&(SP_REFL|SP_PURE|SP_BADU)) == SP_REFL) { |
98 |
> |
if (ldot > FTINY && (np->specfl&(SP_REFL|SP_BADU)) == SP_REFL) { |
99 |
|
/* |
100 |
|
* Compute specular reflection coefficient using |
101 |
|
* anisotropic gaussian distribution model. |
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]; |
113 |
– |
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 / np->pdot; |
127 |
> |
dtmp *= omega; |
128 |
|
scalecolor(ctmp, dtmp); |
129 |
|
addcolor(cval, ctmp); |
130 |
|
} |
138 |
|
scalecolor(ctmp, dtmp); |
139 |
|
addcolor(cval, ctmp); |
140 |
|
} |
141 |
< |
if (ldot < -FTINY && (np->specfl&(SP_TRAN|SP_PURE|SP_BADU)) == SP_TRAN) { |
141 |
> |
if (ldot < -FTINY && (np->specfl&(SP_TRAN|SP_BADU)) == SP_TRAN) { |
142 |
|
/* |
143 |
|
* Compute specular transmission. Specular transmission |
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 / np->pdot; |
173 |
> |
dtmp *= np->tspec * omega; |
174 |
|
scalecolor(ctmp, dtmp); |
175 |
|
addcolor(cval, ctmp); |
176 |
|
} |
183 |
|
register RAY *r; |
184 |
|
{ |
185 |
|
ANISODAT nd; |
163 |
– |
double transtest, transdist; |
164 |
– |
double dtmp; |
186 |
|
COLOR ctmp; |
187 |
|
register int i; |
188 |
|
/* easy shadow test */ |
189 |
< |
if (r->crtype & SHADOW && m->otype != MAT_TRANS2) |
190 |
< |
return; |
189 |
> |
if (r->crtype & SHADOW) |
190 |
> |
return(1); |
191 |
|
|
192 |
|
if (m->oargs.nfargs != (m->otype == MAT_TRANS2 ? 8 : 6)) |
193 |
|
objerror(m, USER, "bad number of real arguments"); |
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 <= FTINY || nd.v_alpha <= FTINY) |
205 |
< |
nd.specfl |= SP_PURE; |
206 |
< |
/* reorient if necessary */ |
207 |
< |
if (r->rod < 0.0) |
208 |
< |
flipsurface(r); |
204 |
> |
if (nd.u_alpha < FTINY || nd.v_alpha <= FTINY) |
205 |
> |
objerror(m, USER, "roughness too small"); |
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 */ |
217 |
|
if (nd.pdot < .001) |
218 |
|
nd.pdot = .001; /* non-zero for diraniso() */ |
219 |
|
multcolor(nd.mcolor, r->pcol); /* modify material color */ |
194 |
– |
transtest = 0; |
220 |
|
/* get specular component */ |
221 |
|
if ((nd.rspec = m->oargs.farg[3]) > FTINY) { |
222 |
|
nd.specfl |= SP_REFL; |
226 |
|
else |
227 |
|
setcolor(nd.scolor, 1.0, 1.0, 1.0); |
228 |
|
scalecolor(nd.scolor, nd.rspec); |
204 |
– |
/* improved model */ |
205 |
– |
dtmp = exp(-BSPEC(m)*nd.pdot); |
206 |
– |
for (i = 0; i < 3; i++) |
207 |
– |
colval(nd.scolor,i) += (1.0-colval(nd.scolor,i))*dtmp; |
208 |
– |
nd.rspec += (1.0-nd.rspec)*dtmp; |
229 |
|
/* check threshold */ |
230 |
< |
if (specthresh > FTINY && |
211 |
< |
((specthresh >= 1.-FTINY || |
212 |
< |
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++) |
235 |
|
if (DOT(nd.vrefl, r->ron) <= FTINY) /* penetration? */ |
236 |
|
for (i = 0; i < 3; i++) /* safety measure */ |
237 |
|
nd.vrefl[i] = r->rdir[i] + 2.*r->rod*r->ron[i]; |
220 |
– |
|
221 |
– |
if (!(r->crtype & SHADOW) && nd.specfl & SP_PURE) { |
222 |
– |
RAY lr; |
223 |
– |
if (rayorigin(&lr, r, REFLECTED, nd.rspec) == 0) { |
224 |
– |
VCOPY(lr.rdir, nd.vrefl); |
225 |
– |
rayvalue(&lr); |
226 |
– |
multcolor(lr.rcol, nd.scolor); |
227 |
– |
addcolor(r->rcol, lr.rcol); |
228 |
– |
} |
229 |
– |
} |
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 && |
240 |
< |
((specthresh >= 1.-FTINY || |
241 |
< |
specthresh + |
242 |
< |
(.05 - .1*frandom()) > nd.tspec))) |
247 |
> |
if (specthresh >= nd.tspec-FTINY) |
248 |
|
nd.specfl |= SP_TBLT; |
249 |
< |
if (r->crtype & SHADOW || |
245 |
< |
DOT(r->pert,r->pert) <= FTINY*FTINY) { |
249 |
> |
if (DOT(r->pert,r->pert) <= FTINY*FTINY) { |
250 |
|
VCOPY(nd.prdir, r->rdir); |
247 |
– |
transtest = 2; |
251 |
|
} else { |
252 |
|
for (i = 0; i < 3; i++) /* perturb */ |
253 |
< |
nd.prdir[i] = r->rdir[i] - |
251 |
< |
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 |
259 |
|
} |
260 |
|
} else |
261 |
|
nd.tdiff = nd.tspec = nd.trans = 0.0; |
260 |
– |
/* transmitted ray */ |
261 |
– |
if ((nd.specfl&(SP_TRAN|SP_PURE)) == (SP_TRAN|SP_PURE)) { |
262 |
– |
RAY lr; |
263 |
– |
if (rayorigin(&lr, r, TRANS, nd.tspec) == 0) { |
264 |
– |
VCOPY(lr.rdir, nd.prdir); |
265 |
– |
rayvalue(&lr); |
266 |
– |
scalecolor(lr.rcol, nd.tspec); |
267 |
– |
multcolor(lr.rcol, nd.mcolor); /* modified by color */ |
268 |
– |
addcolor(r->rcol, lr.rcol); |
269 |
– |
transtest *= bright(lr.rcol); |
270 |
– |
transdist = r->rot + lr.rt; |
271 |
– |
} |
272 |
– |
} |
262 |
|
|
274 |
– |
if (r->crtype & SHADOW) /* the rest is shadow */ |
275 |
– |
return; |
263 |
|
/* diffuse reflection */ |
264 |
|
nd.rdiff = 1.0 - nd.trans - nd.rspec; |
265 |
|
|
266 |
< |
if (nd.specfl & SP_PURE && nd.rdiff <= FTINY && nd.tdiff <= FTINY) |
280 |
< |
return; /* 100% pure specular */ |
281 |
< |
|
282 |
< |
if (r->ro->otype == OBJ_FACE || 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 */ |
270 |
|
|
271 |
< |
if (nd.specfl & (SP_REFL|SP_TRAN) && !(nd.specfl & (SP_PURE|SP_BADU))) |
271 |
> |
if (nd.specfl & (SP_REFL|SP_TRAN) && !(nd.specfl & SP_BADU)) |
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 |
281 |
|
addcolor(r->rcol, ctmp); /* add to returned color */ |
282 |
|
} |
283 |
|
if (nd.tdiff > FTINY) { /* ambient from other side */ |
284 |
+ |
FVECT bnorm; |
285 |
+ |
|
286 |
|
flipsurface(r); |
287 |
< |
ambient(ctmp, r); |
287 |
> |
bnorm[0] = -nd.pnorm[0]; |
288 |
> |
bnorm[1] = -nd.pnorm[1]; |
289 |
> |
bnorm[2] = -nd.pnorm[2]; |
290 |
> |
ambient(ctmp, r, bnorm); |
291 |
|
if (nd.specfl & SP_TBLT) |
292 |
|
scalecolor(ctmp, nd.trans); |
293 |
|
else |
298 |
|
} |
299 |
|
/* add direct component */ |
300 |
|
direct(r, diraniso, &nd); |
301 |
< |
/* check distance */ |
302 |
< |
if (transtest > bright(r->rcol)) |
314 |
< |
r->rt = transdist; |
301 |
> |
|
302 |
> |
return(1); |
303 |
|
} |
304 |
|
|
305 |
|
|
321 |
|
np->specfl |= SP_BADU; |
322 |
|
return; |
323 |
|
} |
324 |
< |
multv3(np->u, np->u, mf->f->xfm); |
324 |
> |
if (mf->f != &unitxf) |
325 |
> |
multv3(np->u, np->u, mf->f->xfm); |
326 |
|
fcross(np->v, np->pnorm, np->u); |
327 |
|
if (normalize(np->v) == 0.0) { |
328 |
|
objerror(np->mp, WARNING, "illegal orientation vector"); |
350 |
|
d = urand(ilhash(dimlist,ndims)+samplendx); |
351 |
|
multisamp(rv, 2, d); |
352 |
|
d = 2.0*PI * rv[0]; |
353 |
< |
cosp = np->u_alpha * cos(d); |
354 |
< |
sinp = np->v_alpha * sin(d); |
353 |
> |
cosp = cos(d) * np->u_alpha; |
354 |
> |
sinp = sin(d) * np->v_alpha; |
355 |
|
d = sqrt(cosp*cosp + sinp*sinp); |
356 |
|
cosp /= d; |
357 |
|
sinp /= d; |
382 |
|
d = urand(ilhash(dimlist,ndims)+1823+samplendx); |
383 |
|
multisamp(rv, 2, d); |
384 |
|
d = 2.0*PI * rv[0]; |
385 |
< |
cosp = cos(d); |
386 |
< |
sinp = sin(d); |
385 |
> |
cosp = cos(d) * np->u_alpha; |
386 |
> |
sinp = sin(d) * np->v_alpha; |
387 |
> |
d = sqrt(cosp*cosp + sinp*sinp); |
388 |
> |
cosp /= d; |
389 |
> |
sinp /= d; |
390 |
|
rv[1] = 1.0 - specjitter*rv[1]; |
391 |
|
if (rv[1] <= FTINY) |
392 |
|
d = 1.0; |
393 |
|
else |
394 |
|
d = sqrt(-log(rv[1]) / |
395 |
< |
(cosp*cosp*4./(np->u_alpha*np->u_alpha) + |
396 |
< |
sinp*sinp*4./(np->v_alpha*np->v_alpha))); |
395 |
> |
(cosp*cosp/(np->u_alpha*np->u_alpha) + |
396 |
> |
sinp*sinp/(np->v_alpha*np->u_alpha))); |
397 |
|
for (i = 0; i < 3; i++) |
398 |
|
sr.rdir[i] = np->prdir[i] + |
399 |
|
d*(cosp*np->u[i] + sinp*np->v[i]); |
402 |
|
else |
403 |
|
VCOPY(sr.rdir, np->prdir); /* else no jitter */ |
404 |
|
rayvalue(&sr); |
405 |
< |
multcolor(sr.rcol, np->scolor); |
405 |
> |
scalecolor(sr.rcol, np->tspec); |
406 |
> |
multcolor(sr.rcol, np->mcolor); /* modify by color */ |
407 |
|
addcolor(r->rcol, sr.rcol); |
408 |
|
ndims--; |
409 |
|
} |