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#include "random.h" |
18 |
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|
19 |
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extern double specthresh; /* specular sampling threshold */ |
20 |
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extern double specjitter; /* specular sampling jitter */ |
21 |
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|
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static agaussamp(); |
23 |
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|
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/* |
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* This anisotropic reflection model uses a variant on the |
26 |
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* exponential Gaussian used in normal.c. |
25 |
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* This routine implements the anisotropic Gaussian |
26 |
> |
* model described by Ward in Siggraph `92 article. |
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* We orient the surface towards the incoming ray, so a single |
28 |
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* surface can be used to represent an infinitely thin object. |
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* |
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/* specularity flags */ |
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#define SP_REFL 01 /* has reflected specular component */ |
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#define SP_TRAN 02 /* has transmitted specular */ |
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#define SP_PURE 010 /* purely specular (zero roughness) */ |
45 |
< |
#define SP_BADU 020 /* bad u direction calculation */ |
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< |
#define SP_FLAT 040 /* reflecting surface is flat */ |
44 |
> |
#define SP_FLAT 04 /* reflecting surface is flat */ |
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> |
#define SP_RBLT 010 /* reflection below sample threshold */ |
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> |
#define SP_TBLT 020 /* transmission below threshold */ |
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> |
#define SP_BADU 040 /* bad u direction calculation */ |
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|
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typedef struct { |
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OBJREC *mp; /* material pointer */ |
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short specfl; /* specularity flags, defined above */ |
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COLOR mcolor; /* color of this material */ |
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COLOR scolor; /* color of specular component */ |
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FVECT vrefl; /* vector in reflected direction */ |
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FVECT prdir; /* vector in transmitted direction */ |
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FVECT u, v; /* u and v vectors orienting anisotropy */ |
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double u_alpha; /* u roughness */ |
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double omega; /* light source size */ |
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{ |
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double ldot; |
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double dtmp, dtmp2; |
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> |
double dtmp, dtmp1, dtmp2; |
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FVECT h; |
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double au2, av2; |
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COLOR ctmp; |
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scalecolor(ctmp, dtmp); |
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addcolor(cval, ctmp); |
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} |
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if (ldot > FTINY && (np->specfl&(SP_REFL|SP_PURE|SP_BADU)) == SP_REFL) { |
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> |
if (ldot > FTINY && (np->specfl&(SP_REFL|SP_BADU)) == SP_REFL) { |
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/* |
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* Compute specular reflection coefficient using |
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* anisotropic gaussian distribution model. |
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au2 = av2 = omega/(4.0*PI); |
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else |
107 |
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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; |
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/* half vector */ |
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h[0] = ldir[0] - np->rp->rdir[0]; |
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h[1] = ldir[1] - np->rp->rdir[1]; |
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h[2] = ldir[2] - np->rp->rdir[2]; |
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normalize(h); |
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/* ellipse */ |
115 |
< |
dtmp = DOT(np->u, h); |
116 |
< |
dtmp *= dtmp / au2; |
115 |
> |
dtmp1 = DOT(np->u, h); |
116 |
> |
dtmp1 *= dtmp1 / au2; |
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dtmp2 = DOT(np->v, h); |
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dtmp2 *= dtmp2 / av2; |
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/* gaussian */ |
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< |
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)); |
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/* worth using? */ |
125 |
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if (dtmp > FTINY) { |
126 |
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copycolor(ctmp, np->scolor); |
127 |
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dtmp *= omega / np->pdot; |
127 |
> |
dtmp *= omega; |
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scalecolor(ctmp, dtmp); |
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addcolor(cval, ctmp); |
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} |
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scalecolor(ctmp, dtmp); |
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addcolor(cval, ctmp); |
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} |
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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) { |
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/* |
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* Compute specular transmission. Specular transmission |
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* is always modified by material color. |
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*/ |
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/* 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 |
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h[0] = ldir[0] - np->prdir[0]; |
152 |
+ |
h[1] = ldir[1] - np->prdir[1]; |
153 |
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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; |
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/* gaussian */ |
168 |
< |
dtmp = 0.0; |
168 |
> |
dtmp = exp(-dtmp) * (1.0/PI) |
169 |
> |
* sqrt(-ldot/(np->pdot*au2*av2)); |
170 |
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/* worth using? */ |
171 |
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if (dtmp > FTINY) { |
172 |
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copycolor(ctmp, np->mcolor); |
173 |
< |
dtmp *= np->tspec * omega / np->pdot; |
173 |
> |
dtmp *= np->tspec * omega; |
174 |
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scalecolor(ctmp, dtmp); |
175 |
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addcolor(cval, ctmp); |
176 |
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} |
183 |
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register RAY *r; |
184 |
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{ |
185 |
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ANISODAT nd; |
157 |
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double transtest, transdist; |
186 |
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double dtmp; |
187 |
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COLOR ctmp; |
188 |
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register int i; |
189 |
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/* easy shadow test */ |
190 |
< |
if (r->crtype & SHADOW && m->otype != MAT_TRANS2) |
190 |
> |
if (r->crtype & SHADOW) |
191 |
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return; |
192 |
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|
193 |
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if (m->oargs.nfargs != (m->otype == MAT_TRANS2 ? 8 : 6)) |
202 |
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nd.specfl = 0; |
203 |
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nd.u_alpha = m->oargs.farg[4]; |
204 |
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nd.v_alpha = m->oargs.farg[5]; |
205 |
< |
if (nd.u_alpha <= FTINY || nd.v_alpha <= FTINY) |
206 |
< |
nd.specfl |= SP_PURE; |
205 |
> |
if (nd.u_alpha < FTINY || nd.v_alpha <= FTINY) |
206 |
> |
objerror(m, USER, "roughness too small"); |
207 |
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/* reorient if necessary */ |
208 |
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if (r->rod < 0.0) |
209 |
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flipsurface(r); |
213 |
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if (nd.pdot < .001) |
214 |
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nd.pdot = .001; /* non-zero for diraniso() */ |
215 |
|
multcolor(nd.mcolor, r->pcol); /* modify material color */ |
188 |
– |
transtest = 0; |
216 |
|
/* get specular component */ |
217 |
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if ((nd.rspec = m->oargs.farg[3]) > FTINY) { |
218 |
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nd.specfl |= SP_REFL; |
227 |
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for (i = 0; i < 3; i++) |
228 |
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colval(nd.scolor,i) += (1.0-colval(nd.scolor,i))*dtmp; |
229 |
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nd.rspec += (1.0-nd.rspec)*dtmp; |
230 |
< |
|
231 |
< |
if (!(r->crtype & SHADOW) && nd.specfl & SP_PURE) { |
232 |
< |
RAY lr; |
233 |
< |
if (rayorigin(&lr, r, REFLECTED, nd.rspec) == 0) { |
234 |
< |
for (i = 0; i < 3; i++) |
235 |
< |
lr.rdir[i] = r->rdir[i] + |
236 |
< |
2.0*nd.pdot*nd.pnorm[i]; |
237 |
< |
rayvalue(&lr); |
238 |
< |
multcolor(lr.rcol, nd.scolor); |
239 |
< |
addcolor(r->rcol, lr.rcol); |
240 |
< |
} |
214 |
< |
} |
230 |
> |
/* check threshold */ |
231 |
> |
if (specthresh > FTINY && |
232 |
> |
(specthresh >= 1.-FTINY || |
233 |
> |
specthresh + .05 - .1*frandom() > nd.rspec)) |
234 |
> |
nd.specfl |= SP_RBLT; |
235 |
> |
/* compute refl. direction */ |
236 |
> |
for (i = 0; i < 3; i++) |
237 |
> |
nd.vrefl[i] = r->rdir[i] + 2.0*nd.pdot*nd.pnorm[i]; |
238 |
> |
if (DOT(nd.vrefl, r->ron) <= FTINY) /* penetration? */ |
239 |
> |
for (i = 0; i < 3; i++) /* safety measure */ |
240 |
> |
nd.vrefl[i] = r->rdir[i] + 2.*r->rod*r->ron[i]; |
241 |
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} |
242 |
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/* compute transmission */ |
243 |
< |
if (m->otype == MAT_TRANS) { |
243 |
> |
if (m->otype == MAT_TRANS2) { |
244 |
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nd.trans = m->oargs.farg[6]*(1.0 - nd.rspec); |
245 |
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nd.tspec = nd.trans * m->oargs.farg[7]; |
246 |
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nd.tdiff = nd.trans - nd.tspec; |
247 |
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if (nd.tspec > FTINY) { |
248 |
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nd.specfl |= SP_TRAN; |
249 |
< |
if (r->crtype & SHADOW || |
250 |
< |
DOT(r->pert,r->pert) <= FTINY*FTINY) { |
249 |
> |
/* check threshold */ |
250 |
> |
if (specthresh > FTINY && |
251 |
> |
(specthresh >= 1.-FTINY || |
252 |
> |
specthresh + .05 - .1*frandom() > nd.tspec)) |
253 |
> |
nd.specfl |= SP_TBLT; |
254 |
> |
if (DOT(r->pert,r->pert) <= FTINY*FTINY) { |
255 |
|
VCOPY(nd.prdir, r->rdir); |
226 |
– |
transtest = 2; |
256 |
|
} else { |
257 |
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for (i = 0; i < 3; i++) /* perturb */ |
258 |
< |
nd.prdir[i] = r->rdir[i] - |
259 |
< |
.75*r->pert[i]; |
260 |
< |
normalize(nd.prdir); |
258 |
> |
nd.prdir[i] = r->rdir[i] - r->pert[i]; |
259 |
> |
if (DOT(nd.prdir, r->ron) < -FTINY) |
260 |
> |
normalize(nd.prdir); /* OK */ |
261 |
> |
else |
262 |
> |
VCOPY(nd.prdir, r->rdir); |
263 |
|
} |
264 |
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} |
265 |
|
} else |
266 |
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nd.tdiff = nd.tspec = nd.trans = 0.0; |
236 |
– |
/* transmitted ray */ |
237 |
– |
if ((nd.specfl&(SP_TRAN|SP_PURE)) == (SP_TRAN|SP_PURE)) { |
238 |
– |
RAY lr; |
239 |
– |
if (rayorigin(&lr, r, TRANS, nd.tspec) == 0) { |
240 |
– |
VCOPY(lr.rdir, nd.prdir); |
241 |
– |
rayvalue(&lr); |
242 |
– |
scalecolor(lr.rcol, nd.tspec); |
243 |
– |
multcolor(lr.rcol, nd.mcolor); /* modified by color */ |
244 |
– |
addcolor(r->rcol, lr.rcol); |
245 |
– |
transtest *= bright(lr.rcol); |
246 |
– |
transdist = r->rot + lr.rt; |
247 |
– |
} |
248 |
– |
} |
267 |
|
|
250 |
– |
if (r->crtype & SHADOW) /* the rest is shadow */ |
251 |
– |
return; |
268 |
|
/* diffuse reflection */ |
269 |
|
nd.rdiff = 1.0 - nd.trans - nd.rspec; |
270 |
|
|
271 |
< |
if (nd.specfl & SP_PURE && nd.rdiff <= FTINY && nd.tdiff <= FTINY) |
272 |
< |
return; /* 100% pure specular */ |
271 |
> |
if (r->ro != NULL && (r->ro->otype == OBJ_FACE || |
272 |
> |
r->ro->otype == OBJ_RING)) |
273 |
> |
nd.specfl |= SP_FLAT; |
274 |
|
|
275 |
|
getacoords(r, &nd); /* set up coordinates */ |
276 |
|
|
277 |
< |
if (nd.specfl & (SP_REFL|SP_TRAN) && !(nd.specfl & (SP_PURE|SP_BADU))) |
277 |
> |
if (nd.specfl & (SP_REFL|SP_TRAN) && !(nd.specfl & SP_BADU)) |
278 |
|
agaussamp(r, &nd); |
279 |
|
|
280 |
|
if (nd.rdiff > FTINY) { /* ambient from this side */ |
281 |
|
ambient(ctmp, r); |
282 |
< |
scalecolor(ctmp, nd.rdiff); |
282 |
> |
if (nd.specfl & SP_RBLT) |
283 |
> |
scalecolor(ctmp, 1.0-nd.trans); |
284 |
> |
else |
285 |
> |
scalecolor(ctmp, nd.rdiff); |
286 |
|
multcolor(ctmp, nd.mcolor); /* modified by material color */ |
287 |
|
addcolor(r->rcol, ctmp); /* add to returned color */ |
288 |
|
} |
289 |
|
if (nd.tdiff > FTINY) { /* ambient from other side */ |
290 |
|
flipsurface(r); |
291 |
|
ambient(ctmp, r); |
292 |
< |
scalecolor(ctmp, nd.tdiff); |
292 |
> |
if (nd.specfl & SP_TBLT) |
293 |
> |
scalecolor(ctmp, nd.trans); |
294 |
> |
else |
295 |
> |
scalecolor(ctmp, nd.tdiff); |
296 |
|
multcolor(ctmp, nd.mcolor); /* modified by color */ |
297 |
|
addcolor(r->rcol, ctmp); |
298 |
|
flipsurface(r); |
299 |
|
} |
300 |
|
/* add direct component */ |
301 |
|
direct(r, diraniso, &nd); |
279 |
– |
/* check distance */ |
280 |
– |
if (transtest > bright(r->rcol)) |
281 |
– |
r->rt = transdist; |
302 |
|
} |
303 |
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|
304 |
|
|
320 |
|
np->specfl |= SP_BADU; |
321 |
|
return; |
322 |
|
} |
323 |
< |
multv3(np->u, np->u, mf->f->xfm); |
323 |
> |
if (mf->f != &unitxf) |
324 |
> |
multv3(np->u, np->u, mf->f->xfm); |
325 |
|
fcross(np->v, np->pnorm, np->u); |
326 |
|
if (normalize(np->v) == 0.0) { |
327 |
|
objerror(np->mp, WARNING, "illegal orientation vector"); |
341 |
|
FVECT h; |
342 |
|
double rv[2]; |
343 |
|
double d, sinp, cosp; |
323 |
– |
int confuse; |
344 |
|
register int i; |
345 |
|
/* compute reflection */ |
346 |
< |
if (np->specfl & SP_REFL && |
346 |
> |
if ((np->specfl & (SP_REFL|SP_RBLT)) == SP_REFL && |
347 |
|
rayorigin(&sr, r, SPECULAR, np->rspec) == 0) { |
328 |
– |
confuse = 0; |
348 |
|
dimlist[ndims++] = (int)np->mp; |
349 |
< |
refagain: |
331 |
< |
dimlist[ndims] = confuse += 3601; |
332 |
< |
d = urand(ilhash(dimlist,ndims+1)+samplendx); |
349 |
> |
d = urand(ilhash(dimlist,ndims)+samplendx); |
350 |
|
multisamp(rv, 2, d); |
351 |
|
d = 2.0*PI * rv[0]; |
352 |
< |
cosp = np->u_alpha * cos(d); |
353 |
< |
sinp = np->v_alpha * sin(d); |
352 |
> |
cosp = cos(d) * np->u_alpha; |
353 |
> |
sinp = sin(d) * np->v_alpha; |
354 |
|
d = sqrt(cosp*cosp + sinp*sinp); |
355 |
|
cosp /= d; |
356 |
|
sinp /= d; |
357 |
+ |
rv[1] = 1.0 - specjitter*rv[1]; |
358 |
|
if (rv[1] <= FTINY) |
359 |
|
d = 1.0; |
360 |
|
else |
361 |
< |
d = sqrt( -log(rv[1]) / |
361 |
> |
d = sqrt(-log(rv[1]) / |
362 |
|
(cosp*cosp/(np->u_alpha*np->u_alpha) + |
363 |
< |
sinp*sinp/(np->v_alpha*np->v_alpha)) ); |
363 |
> |
sinp*sinp/(np->v_alpha*np->v_alpha))); |
364 |
|
for (i = 0; i < 3; i++) |
365 |
|
h[i] = np->pnorm[i] + |
366 |
< |
d*(cosp*np->u[i] + sinp*np->v[i]); |
366 |
> |
d*(cosp*np->u[i] + sinp*np->v[i]); |
367 |
|
d = -2.0 * DOT(h, r->rdir) / (1.0 + d*d); |
368 |
|
for (i = 0; i < 3; i++) |
369 |
|
sr.rdir[i] = r->rdir[i] + d*h[i]; |
370 |
< |
if (DOT(sr.rdir, r->ron) <= FTINY) /* oops! */ |
371 |
< |
goto refagain; |
370 |
> |
if (DOT(sr.rdir, r->ron) <= FTINY) /* penetration? */ |
371 |
> |
VCOPY(sr.rdir, np->vrefl); /* jitter no good */ |
372 |
|
rayvalue(&sr); |
373 |
|
multcolor(sr.rcol, np->scolor); |
374 |
|
addcolor(r->rcol, sr.rcol); |
375 |
|
ndims--; |
376 |
|
} |
377 |
|
/* compute transmission */ |
378 |
+ |
if ((np->specfl & (SP_TRAN|SP_TBLT)) == SP_TRAN && |
379 |
+ |
rayorigin(&sr, r, SPECULAR, np->tspec) == 0) { |
380 |
+ |
dimlist[ndims++] = (int)np->mp; |
381 |
+ |
d = urand(ilhash(dimlist,ndims)+1823+samplendx); |
382 |
+ |
multisamp(rv, 2, d); |
383 |
+ |
d = 2.0*PI * rv[0]; |
384 |
+ |
cosp = cos(d) * np->u_alpha; |
385 |
+ |
sinp = sin(d) * np->v_alpha; |
386 |
+ |
d = sqrt(cosp*cosp + sinp*sinp); |
387 |
+ |
cosp /= d; |
388 |
+ |
sinp /= d; |
389 |
+ |
rv[1] = 1.0 - specjitter*rv[1]; |
390 |
+ |
if (rv[1] <= FTINY) |
391 |
+ |
d = 1.0; |
392 |
+ |
else |
393 |
+ |
d = sqrt(-log(rv[1]) / |
394 |
+ |
(cosp*cosp/(np->u_alpha*np->u_alpha) + |
395 |
+ |
sinp*sinp/(np->v_alpha*np->u_alpha))); |
396 |
+ |
for (i = 0; i < 3; i++) |
397 |
+ |
sr.rdir[i] = np->prdir[i] + |
398 |
+ |
d*(cosp*np->u[i] + sinp*np->v[i]); |
399 |
+ |
if (DOT(sr.rdir, r->ron) < -FTINY) |
400 |
+ |
normalize(sr.rdir); /* OK, normalize */ |
401 |
+ |
else |
402 |
+ |
VCOPY(sr.rdir, np->prdir); /* else no jitter */ |
403 |
+ |
rayvalue(&sr); |
404 |
+ |
scalecolor(sr.rcol, np->tspec); |
405 |
+ |
multcolor(sr.rcol, np->mcolor); /* modify by color */ |
406 |
+ |
addcolor(r->rcol, sr.rcol); |
407 |
+ |
ndims--; |
408 |
+ |
} |
409 |
|
} |