| 1 |
greg |
2.1 |
/* Copyright (c) 1992 Regents of the University of California */ |
| 2 |
|
|
|
| 3 |
|
|
#ifndef lint |
| 4 |
|
|
static char SCCSid[] = "$SunId$ LBL"; |
| 5 |
|
|
#endif |
| 6 |
|
|
|
| 7 |
|
|
/* |
| 8 |
|
|
* Shading functions for anisotropic materials. |
| 9 |
|
|
*/ |
| 10 |
|
|
|
| 11 |
|
|
#include "ray.h" |
| 12 |
|
|
|
| 13 |
|
|
#include "otypes.h" |
| 14 |
|
|
|
| 15 |
|
|
#include "func.h" |
| 16 |
|
|
|
| 17 |
|
|
#include "random.h" |
| 18 |
|
|
|
| 19 |
greg |
2.4 |
extern double specthresh; /* specular sampling threshold */ |
| 20 |
|
|
extern double specjitter; /* specular sampling jitter */ |
| 21 |
|
|
|
| 22 |
greg |
2.1 |
/* |
| 23 |
|
|
* This anisotropic reflection model uses a variant on the |
| 24 |
|
|
* exponential Gaussian used in normal.c. |
| 25 |
|
|
* We orient the surface towards the incoming ray, so a single |
| 26 |
|
|
* surface can be used to represent an infinitely thin object. |
| 27 |
|
|
* |
| 28 |
|
|
* Arguments for MAT_PLASTIC2 and MAT_METAL2 are: |
| 29 |
|
|
* 4+ ux uy uz funcfile [transform...] |
| 30 |
|
|
* 0 |
| 31 |
|
|
* 6 red grn blu specular-frac. u-facet-slope v-facet-slope |
| 32 |
|
|
* |
| 33 |
|
|
* Real arguments for MAT_TRANS2 are: |
| 34 |
|
|
* 8 red grn blu rspec u-rough v-rough trans tspec |
| 35 |
|
|
*/ |
| 36 |
|
|
|
| 37 |
|
|
/* specularity flags */ |
| 38 |
|
|
#define SP_REFL 01 /* has reflected specular component */ |
| 39 |
|
|
#define SP_TRAN 02 /* has transmitted specular */ |
| 40 |
greg |
2.10 |
#define SP_FLAT 04 /* reflecting surface is flat */ |
| 41 |
|
|
#define SP_RBLT 010 /* reflection below sample threshold */ |
| 42 |
|
|
#define SP_TBLT 020 /* transmission below threshold */ |
| 43 |
|
|
#define SP_BADU 040 /* bad u direction calculation */ |
| 44 |
greg |
2.1 |
|
| 45 |
|
|
typedef struct { |
| 46 |
greg |
2.2 |
OBJREC *mp; /* material pointer */ |
| 47 |
greg |
2.1 |
RAY *rp; /* ray pointer */ |
| 48 |
|
|
short specfl; /* specularity flags, defined above */ |
| 49 |
|
|
COLOR mcolor; /* color of this material */ |
| 50 |
|
|
COLOR scolor; /* color of specular component */ |
| 51 |
greg |
2.6 |
FVECT vrefl; /* vector in reflected direction */ |
| 52 |
greg |
2.1 |
FVECT prdir; /* vector in transmitted direction */ |
| 53 |
|
|
FVECT u, v; /* u and v vectors orienting anisotropy */ |
| 54 |
|
|
double u_alpha; /* u roughness */ |
| 55 |
|
|
double v_alpha; /* v roughness */ |
| 56 |
|
|
double rdiff, rspec; /* reflected specular, diffuse */ |
| 57 |
|
|
double trans; /* transmissivity */ |
| 58 |
|
|
double tdiff, tspec; /* transmitted specular, diffuse */ |
| 59 |
|
|
FVECT pnorm; /* perturbed surface normal */ |
| 60 |
|
|
double pdot; /* perturbed dot product */ |
| 61 |
|
|
} ANISODAT; /* anisotropic material data */ |
| 62 |
|
|
|
| 63 |
|
|
|
| 64 |
|
|
diraniso(cval, np, ldir, omega) /* compute source contribution */ |
| 65 |
|
|
COLOR cval; /* returned coefficient */ |
| 66 |
|
|
register ANISODAT *np; /* material data */ |
| 67 |
|
|
FVECT ldir; /* light source direction */ |
| 68 |
|
|
double omega; /* light source size */ |
| 69 |
|
|
{ |
| 70 |
|
|
double ldot; |
| 71 |
|
|
double dtmp, dtmp2; |
| 72 |
|
|
FVECT h; |
| 73 |
|
|
double au2, av2; |
| 74 |
|
|
COLOR ctmp; |
| 75 |
|
|
|
| 76 |
|
|
setcolor(cval, 0.0, 0.0, 0.0); |
| 77 |
|
|
|
| 78 |
|
|
ldot = DOT(np->pnorm, ldir); |
| 79 |
|
|
|
| 80 |
|
|
if (ldot < 0.0 ? np->trans <= FTINY : np->trans >= 1.0-FTINY) |
| 81 |
|
|
return; /* wrong side */ |
| 82 |
|
|
|
| 83 |
|
|
if (ldot > FTINY && np->rdiff > FTINY) { |
| 84 |
|
|
/* |
| 85 |
|
|
* Compute and add diffuse reflected component to returned |
| 86 |
|
|
* color. The diffuse reflected component will always be |
| 87 |
|
|
* modified by the color of the material. |
| 88 |
|
|
*/ |
| 89 |
|
|
copycolor(ctmp, np->mcolor); |
| 90 |
|
|
dtmp = ldot * omega * np->rdiff / PI; |
| 91 |
|
|
scalecolor(ctmp, dtmp); |
| 92 |
|
|
addcolor(cval, ctmp); |
| 93 |
|
|
} |
| 94 |
greg |
2.10 |
if (ldot > FTINY && (np->specfl&(SP_REFL|SP_BADU)) == SP_REFL) { |
| 95 |
greg |
2.1 |
/* |
| 96 |
|
|
* Compute specular reflection coefficient using |
| 97 |
|
|
* anisotropic gaussian distribution model. |
| 98 |
|
|
*/ |
| 99 |
greg |
2.2 |
/* add source width if flat */ |
| 100 |
|
|
if (np->specfl & SP_FLAT) |
| 101 |
|
|
au2 = av2 = omega/(4.0*PI); |
| 102 |
|
|
else |
| 103 |
|
|
au2 = av2 = 0.0; |
| 104 |
greg |
2.1 |
au2 += np->u_alpha * np->u_alpha; |
| 105 |
|
|
av2 += np->v_alpha * np->v_alpha; |
| 106 |
|
|
/* half vector */ |
| 107 |
|
|
h[0] = ldir[0] - np->rp->rdir[0]; |
| 108 |
|
|
h[1] = ldir[1] - np->rp->rdir[1]; |
| 109 |
|
|
h[2] = ldir[2] - np->rp->rdir[2]; |
| 110 |
|
|
normalize(h); |
| 111 |
|
|
/* ellipse */ |
| 112 |
|
|
dtmp = DOT(np->u, h); |
| 113 |
|
|
dtmp *= dtmp / au2; |
| 114 |
|
|
dtmp2 = DOT(np->v, h); |
| 115 |
|
|
dtmp2 *= dtmp2 / av2; |
| 116 |
|
|
/* gaussian */ |
| 117 |
|
|
dtmp = (dtmp + dtmp2) / (1.0 + DOT(np->pnorm, h)); |
| 118 |
|
|
dtmp = exp(-2.0*dtmp) / (4.0*PI * sqrt(au2*av2)); |
| 119 |
|
|
/* worth using? */ |
| 120 |
|
|
if (dtmp > FTINY) { |
| 121 |
|
|
copycolor(ctmp, np->scolor); |
| 122 |
|
|
dtmp *= omega / np->pdot; |
| 123 |
|
|
scalecolor(ctmp, dtmp); |
| 124 |
|
|
addcolor(cval, ctmp); |
| 125 |
|
|
} |
| 126 |
|
|
} |
| 127 |
|
|
if (ldot < -FTINY && np->tdiff > FTINY) { |
| 128 |
|
|
/* |
| 129 |
|
|
* Compute diffuse transmission. |
| 130 |
|
|
*/ |
| 131 |
|
|
copycolor(ctmp, np->mcolor); |
| 132 |
|
|
dtmp = -ldot * omega * np->tdiff / PI; |
| 133 |
|
|
scalecolor(ctmp, dtmp); |
| 134 |
|
|
addcolor(cval, ctmp); |
| 135 |
|
|
} |
| 136 |
greg |
2.10 |
if (ldot < -FTINY && (np->specfl&(SP_TRAN|SP_BADU)) == SP_TRAN) { |
| 137 |
greg |
2.1 |
/* |
| 138 |
|
|
* Compute specular transmission. Specular transmission |
| 139 |
|
|
* is always modified by material color. |
| 140 |
|
|
*/ |
| 141 |
|
|
/* roughness + source */ |
| 142 |
|
|
/* gaussian */ |
| 143 |
|
|
dtmp = 0.0; |
| 144 |
|
|
/* worth using? */ |
| 145 |
|
|
if (dtmp > FTINY) { |
| 146 |
|
|
copycolor(ctmp, np->mcolor); |
| 147 |
|
|
dtmp *= np->tspec * omega / np->pdot; |
| 148 |
|
|
scalecolor(ctmp, dtmp); |
| 149 |
|
|
addcolor(cval, ctmp); |
| 150 |
|
|
} |
| 151 |
|
|
} |
| 152 |
|
|
} |
| 153 |
|
|
|
| 154 |
|
|
|
| 155 |
|
|
m_aniso(m, r) /* shade ray that hit something anisotropic */ |
| 156 |
|
|
register OBJREC *m; |
| 157 |
|
|
register RAY *r; |
| 158 |
|
|
{ |
| 159 |
|
|
ANISODAT nd; |
| 160 |
|
|
double dtmp; |
| 161 |
|
|
COLOR ctmp; |
| 162 |
|
|
register int i; |
| 163 |
|
|
/* easy shadow test */ |
| 164 |
greg |
2.10 |
if (r->crtype & SHADOW) |
| 165 |
greg |
2.1 |
return; |
| 166 |
|
|
|
| 167 |
|
|
if (m->oargs.nfargs != (m->otype == MAT_TRANS2 ? 8 : 6)) |
| 168 |
|
|
objerror(m, USER, "bad number of real arguments"); |
| 169 |
greg |
2.2 |
nd.mp = m; |
| 170 |
greg |
2.1 |
nd.rp = r; |
| 171 |
|
|
/* get material color */ |
| 172 |
|
|
setcolor(nd.mcolor, m->oargs.farg[0], |
| 173 |
|
|
m->oargs.farg[1], |
| 174 |
|
|
m->oargs.farg[2]); |
| 175 |
|
|
/* get roughness */ |
| 176 |
|
|
nd.specfl = 0; |
| 177 |
|
|
nd.u_alpha = m->oargs.farg[4]; |
| 178 |
|
|
nd.v_alpha = m->oargs.farg[5]; |
| 179 |
greg |
2.10 |
if (nd.u_alpha < 1e-6 || nd.v_alpha <= 1e-6) |
| 180 |
|
|
objerror(m, USER, "roughness too small"); |
| 181 |
greg |
2.1 |
/* reorient if necessary */ |
| 182 |
|
|
if (r->rod < 0.0) |
| 183 |
|
|
flipsurface(r); |
| 184 |
|
|
/* get modifiers */ |
| 185 |
|
|
raytexture(r, m->omod); |
| 186 |
|
|
nd.pdot = raynormal(nd.pnorm, r); /* perturb normal */ |
| 187 |
|
|
if (nd.pdot < .001) |
| 188 |
|
|
nd.pdot = .001; /* non-zero for diraniso() */ |
| 189 |
|
|
multcolor(nd.mcolor, r->pcol); /* modify material color */ |
| 190 |
|
|
/* get specular component */ |
| 191 |
|
|
if ((nd.rspec = m->oargs.farg[3]) > FTINY) { |
| 192 |
|
|
nd.specfl |= SP_REFL; |
| 193 |
|
|
/* compute specular color */ |
| 194 |
|
|
if (m->otype == MAT_METAL2) |
| 195 |
|
|
copycolor(nd.scolor, nd.mcolor); |
| 196 |
|
|
else |
| 197 |
|
|
setcolor(nd.scolor, 1.0, 1.0, 1.0); |
| 198 |
|
|
scalecolor(nd.scolor, nd.rspec); |
| 199 |
greg |
2.4 |
/* check threshold */ |
| 200 |
greg |
2.5 |
if (specthresh > FTINY && |
| 201 |
greg |
2.12 |
(specthresh >= 1.-FTINY || |
| 202 |
|
|
specthresh > nd.rspec)) |
| 203 |
greg |
2.4 |
nd.specfl |= SP_RBLT; |
| 204 |
greg |
2.6 |
/* compute refl. direction */ |
| 205 |
|
|
for (i = 0; i < 3; i++) |
| 206 |
|
|
nd.vrefl[i] = r->rdir[i] + 2.0*nd.pdot*nd.pnorm[i]; |
| 207 |
|
|
if (DOT(nd.vrefl, r->ron) <= FTINY) /* penetration? */ |
| 208 |
|
|
for (i = 0; i < 3; i++) /* safety measure */ |
| 209 |
|
|
nd.vrefl[i] = r->rdir[i] + 2.*r->rod*r->ron[i]; |
| 210 |
greg |
2.1 |
} |
| 211 |
|
|
/* compute transmission */ |
| 212 |
|
|
if (m->otype == MAT_TRANS) { |
| 213 |
|
|
nd.trans = m->oargs.farg[6]*(1.0 - nd.rspec); |
| 214 |
|
|
nd.tspec = nd.trans * m->oargs.farg[7]; |
| 215 |
|
|
nd.tdiff = nd.trans - nd.tspec; |
| 216 |
|
|
if (nd.tspec > FTINY) { |
| 217 |
|
|
nd.specfl |= SP_TRAN; |
| 218 |
greg |
2.4 |
/* check threshold */ |
| 219 |
greg |
2.5 |
if (specthresh > FTINY && |
| 220 |
greg |
2.12 |
(specthresh >= 1.-FTINY || |
| 221 |
|
|
specthresh > nd.tspec)) |
| 222 |
greg |
2.4 |
nd.specfl |= SP_TBLT; |
| 223 |
greg |
2.10 |
if (DOT(r->pert,r->pert) <= FTINY*FTINY) { |
| 224 |
greg |
2.1 |
VCOPY(nd.prdir, r->rdir); |
| 225 |
|
|
} else { |
| 226 |
|
|
for (i = 0; i < 3; i++) /* perturb */ |
| 227 |
|
|
nd.prdir[i] = r->rdir[i] - |
| 228 |
greg |
2.7 |
0.5*r->pert[i]; |
| 229 |
greg |
2.6 |
if (DOT(nd.prdir, r->ron) < -FTINY) |
| 230 |
|
|
normalize(nd.prdir); /* OK */ |
| 231 |
|
|
else |
| 232 |
|
|
VCOPY(nd.prdir, r->rdir); |
| 233 |
greg |
2.1 |
} |
| 234 |
|
|
} |
| 235 |
|
|
} else |
| 236 |
|
|
nd.tdiff = nd.tspec = nd.trans = 0.0; |
| 237 |
|
|
|
| 238 |
|
|
/* diffuse reflection */ |
| 239 |
|
|
nd.rdiff = 1.0 - nd.trans - nd.rspec; |
| 240 |
|
|
|
| 241 |
greg |
2.11 |
if (r->ro != NULL && (r->ro->otype == OBJ_FACE || |
| 242 |
|
|
r->ro->otype == OBJ_RING)) |
| 243 |
greg |
2.4 |
nd.specfl |= SP_FLAT; |
| 244 |
|
|
|
| 245 |
greg |
2.1 |
getacoords(r, &nd); /* set up coordinates */ |
| 246 |
|
|
|
| 247 |
greg |
2.10 |
if (nd.specfl & (SP_REFL|SP_TRAN) && !(nd.specfl & SP_BADU)) |
| 248 |
greg |
2.1 |
agaussamp(r, &nd); |
| 249 |
|
|
|
| 250 |
|
|
if (nd.rdiff > FTINY) { /* ambient from this side */ |
| 251 |
|
|
ambient(ctmp, r); |
| 252 |
greg |
2.4 |
if (nd.specfl & SP_RBLT) |
| 253 |
|
|
scalecolor(ctmp, 1.0-nd.trans); |
| 254 |
|
|
else |
| 255 |
|
|
scalecolor(ctmp, nd.rdiff); |
| 256 |
greg |
2.1 |
multcolor(ctmp, nd.mcolor); /* modified by material color */ |
| 257 |
|
|
addcolor(r->rcol, ctmp); /* add to returned color */ |
| 258 |
|
|
} |
| 259 |
|
|
if (nd.tdiff > FTINY) { /* ambient from other side */ |
| 260 |
|
|
flipsurface(r); |
| 261 |
|
|
ambient(ctmp, r); |
| 262 |
greg |
2.4 |
if (nd.specfl & SP_TBLT) |
| 263 |
|
|
scalecolor(ctmp, nd.trans); |
| 264 |
|
|
else |
| 265 |
|
|
scalecolor(ctmp, nd.tdiff); |
| 266 |
greg |
2.1 |
multcolor(ctmp, nd.mcolor); /* modified by color */ |
| 267 |
|
|
addcolor(r->rcol, ctmp); |
| 268 |
|
|
flipsurface(r); |
| 269 |
|
|
} |
| 270 |
|
|
/* add direct component */ |
| 271 |
|
|
direct(r, diraniso, &nd); |
| 272 |
|
|
} |
| 273 |
|
|
|
| 274 |
|
|
|
| 275 |
|
|
static |
| 276 |
|
|
getacoords(r, np) /* set up coordinate system */ |
| 277 |
|
|
RAY *r; |
| 278 |
|
|
register ANISODAT *np; |
| 279 |
|
|
{ |
| 280 |
|
|
register MFUNC *mf; |
| 281 |
|
|
register int i; |
| 282 |
|
|
|
| 283 |
|
|
mf = getfunc(np->mp, 3, 0x7, 1); |
| 284 |
|
|
setfunc(np->mp, r); |
| 285 |
|
|
errno = 0; |
| 286 |
|
|
for (i = 0; i < 3; i++) |
| 287 |
|
|
np->u[i] = evalue(mf->ep[i]); |
| 288 |
|
|
if (errno) { |
| 289 |
|
|
objerror(np->mp, WARNING, "compute error"); |
| 290 |
|
|
np->specfl |= SP_BADU; |
| 291 |
|
|
return; |
| 292 |
|
|
} |
| 293 |
|
|
multv3(np->u, np->u, mf->f->xfm); |
| 294 |
|
|
fcross(np->v, np->pnorm, np->u); |
| 295 |
|
|
if (normalize(np->v) == 0.0) { |
| 296 |
|
|
objerror(np->mp, WARNING, "illegal orientation vector"); |
| 297 |
|
|
np->specfl |= SP_BADU; |
| 298 |
|
|
return; |
| 299 |
|
|
} |
| 300 |
|
|
fcross(np->u, np->v, np->pnorm); |
| 301 |
|
|
} |
| 302 |
|
|
|
| 303 |
|
|
|
| 304 |
|
|
static |
| 305 |
|
|
agaussamp(r, np) /* sample anisotropic gaussian specular */ |
| 306 |
|
|
RAY *r; |
| 307 |
|
|
register ANISODAT *np; |
| 308 |
|
|
{ |
| 309 |
|
|
RAY sr; |
| 310 |
|
|
FVECT h; |
| 311 |
|
|
double rv[2]; |
| 312 |
|
|
double d, sinp, cosp; |
| 313 |
|
|
register int i; |
| 314 |
|
|
/* compute reflection */ |
| 315 |
greg |
2.4 |
if ((np->specfl & (SP_REFL|SP_RBLT)) == SP_REFL && |
| 316 |
greg |
2.1 |
rayorigin(&sr, r, SPECULAR, np->rspec) == 0) { |
| 317 |
|
|
dimlist[ndims++] = (int)np->mp; |
| 318 |
greg |
2.6 |
d = urand(ilhash(dimlist,ndims)+samplendx); |
| 319 |
|
|
multisamp(rv, 2, d); |
| 320 |
|
|
d = 2.0*PI * rv[0]; |
| 321 |
|
|
cosp = np->u_alpha * cos(d); |
| 322 |
|
|
sinp = np->v_alpha * sin(d); |
| 323 |
|
|
d = sqrt(cosp*cosp + sinp*sinp); |
| 324 |
|
|
cosp /= d; |
| 325 |
|
|
sinp /= d; |
| 326 |
|
|
rv[1] = 1.0 - specjitter*rv[1]; |
| 327 |
|
|
if (rv[1] <= FTINY) |
| 328 |
|
|
d = 1.0; |
| 329 |
|
|
else |
| 330 |
|
|
d = sqrt(-log(rv[1]) / |
| 331 |
|
|
(cosp*cosp/(np->u_alpha*np->u_alpha) + |
| 332 |
|
|
sinp*sinp/(np->v_alpha*np->v_alpha))); |
| 333 |
|
|
for (i = 0; i < 3; i++) |
| 334 |
|
|
h[i] = np->pnorm[i] + |
| 335 |
|
|
d*(cosp*np->u[i] + sinp*np->v[i]); |
| 336 |
|
|
d = -2.0 * DOT(h, r->rdir) / (1.0 + d*d); |
| 337 |
|
|
for (i = 0; i < 3; i++) |
| 338 |
|
|
sr.rdir[i] = r->rdir[i] + d*h[i]; |
| 339 |
|
|
if (DOT(sr.rdir, r->ron) <= FTINY) /* penetration? */ |
| 340 |
|
|
VCOPY(sr.rdir, np->vrefl); /* jitter no good */ |
| 341 |
|
|
rayvalue(&sr); |
| 342 |
|
|
multcolor(sr.rcol, np->scolor); |
| 343 |
|
|
addcolor(r->rcol, sr.rcol); |
| 344 |
greg |
2.1 |
ndims--; |
| 345 |
|
|
} |
| 346 |
|
|
/* compute transmission */ |
| 347 |
greg |
2.7 |
if ((np->specfl & (SP_TRAN|SP_TBLT)) == SP_TRAN && |
| 348 |
|
|
rayorigin(&sr, r, SPECULAR, np->tspec) == 0) { |
| 349 |
|
|
dimlist[ndims++] = (int)np->mp; |
| 350 |
|
|
d = urand(ilhash(dimlist,ndims)+1823+samplendx); |
| 351 |
|
|
multisamp(rv, 2, d); |
| 352 |
|
|
d = 2.0*PI * rv[0]; |
| 353 |
|
|
cosp = cos(d); |
| 354 |
|
|
sinp = sin(d); |
| 355 |
|
|
rv[1] = 1.0 - specjitter*rv[1]; |
| 356 |
|
|
if (rv[1] <= FTINY) |
| 357 |
|
|
d = 1.0; |
| 358 |
|
|
else |
| 359 |
|
|
d = sqrt(-log(rv[1]) / |
| 360 |
|
|
(cosp*cosp*4./(np->u_alpha*np->u_alpha) + |
| 361 |
|
|
sinp*sinp*4./(np->v_alpha*np->v_alpha))); |
| 362 |
|
|
for (i = 0; i < 3; i++) |
| 363 |
|
|
sr.rdir[i] = np->prdir[i] + |
| 364 |
|
|
d*(cosp*np->u[i] + sinp*np->v[i]); |
| 365 |
|
|
if (DOT(sr.rdir, r->ron) < -FTINY) |
| 366 |
|
|
normalize(sr.rdir); /* OK, normalize */ |
| 367 |
|
|
else |
| 368 |
|
|
VCOPY(sr.rdir, np->prdir); /* else no jitter */ |
| 369 |
|
|
rayvalue(&sr); |
| 370 |
greg |
2.10 |
scalecolor(sr.rcol, np->tspec); |
| 371 |
|
|
multcolor(sr.rcol, np->mcolor); /* modify by color */ |
| 372 |
greg |
2.7 |
addcolor(r->rcol, sr.rcol); |
| 373 |
|
|
ndims--; |
| 374 |
|
|
} |
| 375 |
greg |
2.1 |
} |
