| 1 |
#ifndef lint |
| 2 |
static const char RCSid[] = "$Id: source.c,v 2.40 2003/12/31 19:38:27 greg Exp $"; |
| 3 |
#endif |
| 4 |
/* |
| 5 |
* source.c - routines dealing with illumination sources. |
| 6 |
* |
| 7 |
* External symbols declared in source.h |
| 8 |
*/ |
| 9 |
|
| 10 |
#include "ray.h" |
| 11 |
|
| 12 |
#include "otypes.h" |
| 13 |
|
| 14 |
#include "source.h" |
| 15 |
|
| 16 |
#include "random.h" |
| 17 |
|
| 18 |
extern double ssampdist; /* scatter sampling distance */ |
| 19 |
|
| 20 |
#ifndef MAXSSAMP |
| 21 |
#define MAXSSAMP 16 /* maximum samples per ray */ |
| 22 |
#endif |
| 23 |
|
| 24 |
/* |
| 25 |
* Structures used by direct() |
| 26 |
*/ |
| 27 |
|
| 28 |
typedef struct { |
| 29 |
int sno; /* source number */ |
| 30 |
FVECT dir; /* source direction */ |
| 31 |
COLOR coef; /* material coefficient */ |
| 32 |
COLOR val; /* contribution */ |
| 33 |
} CONTRIB; /* direct contribution */ |
| 34 |
|
| 35 |
typedef struct { |
| 36 |
int sndx; /* source index (to CONTRIB array) */ |
| 37 |
float brt; /* brightness (for comparison) */ |
| 38 |
} CNTPTR; /* contribution pointer */ |
| 39 |
|
| 40 |
static CONTRIB *srccnt; /* source contributions in direct() */ |
| 41 |
static CNTPTR *cntord; /* source ordering in direct() */ |
| 42 |
static int maxcntr = 0; /* size of contribution arrays */ |
| 43 |
|
| 44 |
|
| 45 |
OBJREC * /* find an object's actual material */ |
| 46 |
findmaterial(register OBJREC *o) |
| 47 |
{ |
| 48 |
while (!ismaterial(o->otype)) { |
| 49 |
if (ismixture(o->otype)) |
| 50 |
return(NULL); /* reject mixed materials */ |
| 51 |
if (o->otype == MOD_ALIAS && o->oargs.nsargs) { |
| 52 |
OBJECT aobj; |
| 53 |
OBJREC *ao; |
| 54 |
aobj = lastmod(objndx(o), o->oargs.sarg[0]); |
| 55 |
if (aobj < 0) |
| 56 |
objerror(o, USER, "bad reference"); |
| 57 |
ao = objptr(aobj); |
| 58 |
if (ismaterial(ao->otype)) |
| 59 |
return(ao); |
| 60 |
} |
| 61 |
if (o->omod == OVOID) |
| 62 |
return(NULL); |
| 63 |
o = objptr(o->omod); |
| 64 |
} |
| 65 |
return(o); |
| 66 |
} |
| 67 |
|
| 68 |
|
| 69 |
void |
| 70 |
marksources() /* find and mark source objects */ |
| 71 |
{ |
| 72 |
int foundsource = 0; |
| 73 |
int i; |
| 74 |
register OBJREC *o, *m; |
| 75 |
register int ns; |
| 76 |
/* initialize dispatch table */ |
| 77 |
initstypes(); |
| 78 |
/* find direct sources */ |
| 79 |
for (i = 0; i < nsceneobjs; i++) { |
| 80 |
|
| 81 |
o = objptr(i); |
| 82 |
|
| 83 |
if (!issurface(o->otype) || o->omod == OVOID) |
| 84 |
continue; |
| 85 |
/* find material */ |
| 86 |
m = findmaterial(o); |
| 87 |
if (m == NULL || !islight(m->otype)) |
| 88 |
continue; /* not source modifier */ |
| 89 |
|
| 90 |
if (m->oargs.nfargs != (m->otype == MAT_GLOW ? 4 : |
| 91 |
m->otype == MAT_SPOT ? 7 : 3)) |
| 92 |
objerror(m, USER, "bad # arguments"); |
| 93 |
|
| 94 |
if (m->otype == MAT_GLOW && |
| 95 |
o->otype != OBJ_SOURCE && |
| 96 |
m->oargs.farg[3] <= FTINY) |
| 97 |
continue; /* don't bother */ |
| 98 |
if (m->oargs.farg[0] <= FTINY && m->oargs.farg[1] <= FTINY && |
| 99 |
m->oargs.farg[2] <= FTINY) |
| 100 |
continue; /* don't bother */ |
| 101 |
|
| 102 |
if (sfun[o->otype].of == NULL || |
| 103 |
sfun[o->otype].of->setsrc == NULL) |
| 104 |
objerror(o, USER, "illegal material"); |
| 105 |
|
| 106 |
if ((ns = newsource()) < 0) |
| 107 |
goto memerr; |
| 108 |
|
| 109 |
setsource(&source[ns], o); |
| 110 |
|
| 111 |
if (m->otype == MAT_GLOW) { |
| 112 |
source[ns].sflags |= SPROX; |
| 113 |
source[ns].sl.prox = m->oargs.farg[3]; |
| 114 |
if (source[ns].sflags & SDISTANT) |
| 115 |
source[ns].sflags |= SSKIP; |
| 116 |
} else if (m->otype == MAT_SPOT) { |
| 117 |
source[ns].sflags |= SSPOT; |
| 118 |
if ((source[ns].sl.s = makespot(m)) == NULL) |
| 119 |
goto memerr; |
| 120 |
if (source[ns].sflags & SFLAT && |
| 121 |
!checkspot(source[ns].sl.s,source[ns].snorm)) { |
| 122 |
objerror(o, WARNING, |
| 123 |
"invalid spotlight direction"); |
| 124 |
source[ns].sflags |= SSKIP; |
| 125 |
} |
| 126 |
} |
| 127 |
#if SHADCACHE |
| 128 |
source[ns].obscache = NULL; |
| 129 |
#endif |
| 130 |
if (!(source[ns].sflags & SSKIP)) |
| 131 |
foundsource++; |
| 132 |
} |
| 133 |
if (!foundsource) { |
| 134 |
error(WARNING, "no light sources found"); |
| 135 |
return; |
| 136 |
} |
| 137 |
markvirtuals(); /* find and add virtual sources */ |
| 138 |
/* allocate our contribution arrays */ |
| 139 |
maxcntr = nsources + MAXSPART; /* start with this many */ |
| 140 |
srccnt = (CONTRIB *)malloc(maxcntr*sizeof(CONTRIB)); |
| 141 |
cntord = (CNTPTR *)malloc(maxcntr*sizeof(CNTPTR)); |
| 142 |
if ((srccnt == NULL) | (cntord == NULL)) |
| 143 |
goto memerr; |
| 144 |
return; |
| 145 |
memerr: |
| 146 |
error(SYSTEM, "out of memory in marksources"); |
| 147 |
} |
| 148 |
|
| 149 |
|
| 150 |
void |
| 151 |
freesources() /* free all source structures */ |
| 152 |
{ |
| 153 |
if (nsources > 0) { |
| 154 |
#if SHADCACHE |
| 155 |
while (nsources--) |
| 156 |
freeobscache(&source[nsources]); |
| 157 |
#endif |
| 158 |
free((void *)source); |
| 159 |
source = NULL; |
| 160 |
nsources = 0; |
| 161 |
} |
| 162 |
if (maxcntr <= 0) |
| 163 |
return; |
| 164 |
free((void *)srccnt); |
| 165 |
srccnt = NULL; |
| 166 |
free((void *)cntord); |
| 167 |
cntord = NULL; |
| 168 |
maxcntr = 0; |
| 169 |
} |
| 170 |
|
| 171 |
|
| 172 |
int |
| 173 |
srcray( /* send a ray to a source, return domega */ |
| 174 |
register RAY *sr, /* returned source ray */ |
| 175 |
RAY *r, /* ray which hit object */ |
| 176 |
SRCINDEX *si /* source sample index */ |
| 177 |
) |
| 178 |
{ |
| 179 |
double d; /* distance to source */ |
| 180 |
register SRCREC *srcp; |
| 181 |
|
| 182 |
rayorigin(sr, r, SHADOW, 1.0); /* ignore limits */ |
| 183 |
|
| 184 |
while ((d = nextssamp(sr, si)) != 0.0) { |
| 185 |
sr->rsrc = si->sn; /* remember source */ |
| 186 |
srcp = source + si->sn; |
| 187 |
if (srcp->sflags & SDISTANT) { |
| 188 |
if (srcp->sflags & SSPOT && spotout(sr, srcp->sl.s)) |
| 189 |
continue; |
| 190 |
return(1); /* sample OK */ |
| 191 |
} |
| 192 |
/* local source */ |
| 193 |
/* check proximity */ |
| 194 |
if (srcp->sflags & SPROX && d > srcp->sl.prox) |
| 195 |
continue; |
| 196 |
/* check angle */ |
| 197 |
if (srcp->sflags & SSPOT) { |
| 198 |
if (spotout(sr, srcp->sl.s)) |
| 199 |
continue; |
| 200 |
/* adjust solid angle */ |
| 201 |
si->dom *= d*d; |
| 202 |
d += srcp->sl.s->flen; |
| 203 |
si->dom /= d*d; |
| 204 |
} |
| 205 |
return(1); /* sample OK */ |
| 206 |
} |
| 207 |
return(0); /* no more samples */ |
| 208 |
} |
| 209 |
|
| 210 |
|
| 211 |
void |
| 212 |
srcvalue( /* punch ray to source and compute value */ |
| 213 |
register RAY *r |
| 214 |
) |
| 215 |
{ |
| 216 |
register SRCREC *sp; |
| 217 |
|
| 218 |
sp = &source[r->rsrc]; |
| 219 |
if (sp->sflags & SVIRTUAL) { /* virtual source */ |
| 220 |
/* check intersection */ |
| 221 |
if (!(*ofun[sp->so->otype].funp)(sp->so, r)) |
| 222 |
return; |
| 223 |
if (!rayshade(r, r->ro->omod)) /* compute contribution */ |
| 224 |
goto nomat; |
| 225 |
rayparticipate(r); |
| 226 |
return; |
| 227 |
} |
| 228 |
/* compute intersection */ |
| 229 |
if (sp->sflags & SDISTANT ? sourcehit(r) : |
| 230 |
(*ofun[sp->so->otype].funp)(sp->so, r)) { |
| 231 |
if (sp->sa.success >= 0) |
| 232 |
sp->sa.success++; |
| 233 |
if (!rayshade(r, r->ro->omod)) /* compute contribution */ |
| 234 |
goto nomat; |
| 235 |
rayparticipate(r); |
| 236 |
return; |
| 237 |
} |
| 238 |
/* we missed our mark! */ |
| 239 |
if (sp->sa.success < 0) |
| 240 |
return; /* bitched already */ |
| 241 |
sp->sa.success -= AIMREQT; |
| 242 |
if (sp->sa.success >= 0) |
| 243 |
return; /* leniency */ |
| 244 |
sprintf(errmsg, "aiming failure for light source \"%s\"", |
| 245 |
sp->so->oname); |
| 246 |
error(WARNING, errmsg); /* issue warning */ |
| 247 |
return; |
| 248 |
nomat: |
| 249 |
objerror(r->ro, USER, "material not found"); |
| 250 |
} |
| 251 |
|
| 252 |
|
| 253 |
int |
| 254 |
sourcehit( /* check to see if ray hit distant source */ |
| 255 |
register RAY *r |
| 256 |
) |
| 257 |
{ |
| 258 |
int first, last; |
| 259 |
register int i; |
| 260 |
|
| 261 |
if (r->rsrc >= 0) { /* check only one if aimed */ |
| 262 |
first = last = r->rsrc; |
| 263 |
} else { /* otherwise check all */ |
| 264 |
first = 0; last = nsources-1; |
| 265 |
} |
| 266 |
for (i = first; i <= last; i++) |
| 267 |
if ((source[i].sflags & (SDISTANT|SVIRTUAL)) == SDISTANT) |
| 268 |
/* |
| 269 |
* Check to see if ray is within |
| 270 |
* solid angle of source. |
| 271 |
*/ |
| 272 |
if (2.0*PI * (1.0 - DOT(source[i].sloc,r->rdir)) |
| 273 |
<= source[i].ss2) { |
| 274 |
r->ro = source[i].so; |
| 275 |
if (!(source[i].sflags & SSKIP)) |
| 276 |
break; |
| 277 |
} |
| 278 |
|
| 279 |
if (r->ro != NULL) { |
| 280 |
r->robj = objndx(r->ro); |
| 281 |
for (i = 0; i < 3; i++) |
| 282 |
r->ron[i] = -r->rdir[i]; |
| 283 |
r->rod = 1.0; |
| 284 |
r->pert[0] = r->pert[1] = r->pert[2] = 0.0; |
| 285 |
r->uv[0] = r->uv[1] = 0.0; |
| 286 |
r->rox = NULL; |
| 287 |
return(1); |
| 288 |
} |
| 289 |
return(0); |
| 290 |
} |
| 291 |
|
| 292 |
|
| 293 |
static int |
| 294 |
cntcmp( /* contribution compare (descending) */ |
| 295 |
const void *p1, |
| 296 |
const void *p2 |
| 297 |
) |
| 298 |
{ |
| 299 |
register const CNTPTR *sc1 = (const CNTPTR *)p1; |
| 300 |
register const CNTPTR *sc2 = (const CNTPTR *)p2; |
| 301 |
|
| 302 |
if (sc1->brt > sc2->brt) |
| 303 |
return(-1); |
| 304 |
if (sc1->brt < sc2->brt) |
| 305 |
return(1); |
| 306 |
return(0); |
| 307 |
} |
| 308 |
|
| 309 |
|
| 310 |
void |
| 311 |
direct( /* add direct component */ |
| 312 |
RAY *r, /* ray that hit surface */ |
| 313 |
void (*f)(), /* direct component coefficient function */ |
| 314 |
char *p /* data for f */ |
| 315 |
) |
| 316 |
{ |
| 317 |
extern void (*trace)(); |
| 318 |
register int sn; |
| 319 |
register CONTRIB *scp; |
| 320 |
SRCINDEX si; |
| 321 |
int nshadcheck, ncnts; |
| 322 |
int nhits; |
| 323 |
double prob, ourthresh, hwt; |
| 324 |
RAY sr; |
| 325 |
/* NOTE: srccnt and cntord global so no recursion */ |
| 326 |
if (nsources <= 0) |
| 327 |
return; /* no sources?! */ |
| 328 |
/* potential contributions */ |
| 329 |
initsrcindex(&si); |
| 330 |
for (sn = 0; srcray(&sr, r, &si); sn++) { |
| 331 |
if (sn >= maxcntr) { |
| 332 |
maxcntr = sn + MAXSPART; |
| 333 |
srccnt = (CONTRIB *)realloc((void *)srccnt, |
| 334 |
maxcntr*sizeof(CONTRIB)); |
| 335 |
cntord = (CNTPTR *)realloc((void *)cntord, |
| 336 |
maxcntr*sizeof(CNTPTR)); |
| 337 |
if ((srccnt == NULL) | (cntord == NULL)) |
| 338 |
error(SYSTEM, "out of memory in direct"); |
| 339 |
} |
| 340 |
cntord[sn].sndx = sn; |
| 341 |
scp = srccnt + sn; |
| 342 |
scp->sno = sr.rsrc; |
| 343 |
/* compute coefficient */ |
| 344 |
(*f)(scp->coef, p, sr.rdir, si.dom); |
| 345 |
cntord[sn].brt = bright(scp->coef); |
| 346 |
if (cntord[sn].brt <= 0.0) |
| 347 |
continue; |
| 348 |
#if SHADCACHE |
| 349 |
/* check shadow cache */ |
| 350 |
if (si.np == 1 && srcblocked(&sr)) { |
| 351 |
cntord[sn].brt = 0.0; |
| 352 |
continue; |
| 353 |
} |
| 354 |
#endif |
| 355 |
VCOPY(scp->dir, sr.rdir); |
| 356 |
/* compute potential */ |
| 357 |
sr.revf = srcvalue; |
| 358 |
rayvalue(&sr); |
| 359 |
copycolor(scp->val, sr.rcol); |
| 360 |
multcolor(scp->val, scp->coef); |
| 361 |
cntord[sn].brt = bright(scp->val); |
| 362 |
} |
| 363 |
/* sort contributions */ |
| 364 |
qsort(cntord, sn, sizeof(CNTPTR), cntcmp); |
| 365 |
{ /* find last */ |
| 366 |
register int l, m; |
| 367 |
|
| 368 |
ncnts = l = sn; |
| 369 |
sn = 0; |
| 370 |
while ((m = (sn + ncnts) >> 1) != l) { |
| 371 |
if (cntord[m].brt > 0.0) |
| 372 |
sn = m; |
| 373 |
else |
| 374 |
ncnts = m; |
| 375 |
l = m; |
| 376 |
} |
| 377 |
} |
| 378 |
if (ncnts == 0) |
| 379 |
return; /* no contributions! */ |
| 380 |
/* accumulate tail */ |
| 381 |
for (sn = ncnts-1; sn > 0; sn--) |
| 382 |
cntord[sn-1].brt += cntord[sn].brt; |
| 383 |
/* compute number to check */ |
| 384 |
nshadcheck = pow((double)ncnts, shadcert) + .5; |
| 385 |
/* modify threshold */ |
| 386 |
ourthresh = shadthresh / r->rweight; |
| 387 |
/* test for shadows */ |
| 388 |
for (nhits = 0, hwt = 0.0, sn = 0; sn < ncnts; |
| 389 |
hwt += (double)source[scp->sno].nhits / |
| 390 |
(double)source[scp->sno].ntests, |
| 391 |
sn++) { |
| 392 |
/* check threshold */ |
| 393 |
if ((sn+nshadcheck>=ncnts ? cntord[sn].brt : |
| 394 |
cntord[sn].brt-cntord[sn+nshadcheck].brt) |
| 395 |
< ourthresh*bright(r->rcol)) |
| 396 |
break; |
| 397 |
scp = srccnt + cntord[sn].sndx; |
| 398 |
/* test for hit */ |
| 399 |
rayorigin(&sr, r, SHADOW, 1.0); |
| 400 |
VCOPY(sr.rdir, scp->dir); |
| 401 |
sr.rsrc = scp->sno; |
| 402 |
/* keep statistics */ |
| 403 |
if (source[scp->sno].ntests++ > 0xfffffff0) { |
| 404 |
source[scp->sno].ntests >>= 1; |
| 405 |
source[scp->sno].nhits >>= 1; |
| 406 |
} |
| 407 |
if (localhit(&sr, &thescene) && |
| 408 |
( sr.ro != source[scp->sno].so || |
| 409 |
source[scp->sno].sflags & SFOLLOW )) { |
| 410 |
/* follow entire path */ |
| 411 |
raycont(&sr); |
| 412 |
rayparticipate(&sr); |
| 413 |
if (trace != NULL) |
| 414 |
(*trace)(&sr); /* trace execution */ |
| 415 |
if (bright(sr.rcol) <= FTINY) { |
| 416 |
#if SHADCACHE |
| 417 |
if ((scp <= srccnt || scp[-1].sno != scp->sno) |
| 418 |
&& (scp >= srccnt+ncnts-1 || |
| 419 |
scp[1].sno != scp->sno)) |
| 420 |
srcblocker(&sr); |
| 421 |
#endif |
| 422 |
continue; /* missed! */ |
| 423 |
} |
| 424 |
copycolor(scp->val, sr.rcol); |
| 425 |
multcolor(scp->val, scp->coef); |
| 426 |
} |
| 427 |
/* add contribution if hit */ |
| 428 |
addcolor(r->rcol, scp->val); |
| 429 |
nhits++; |
| 430 |
source[scp->sno].nhits++; |
| 431 |
} |
| 432 |
/* source hit rate */ |
| 433 |
if (hwt > FTINY) |
| 434 |
hwt = (double)nhits / hwt; |
| 435 |
else |
| 436 |
hwt = 0.5; |
| 437 |
#ifdef DEBUG |
| 438 |
sprintf(errmsg, "%d tested, %d untested, %f conditional hit rate\n", |
| 439 |
sn, ncnts-sn, hwt); |
| 440 |
eputs(errmsg); |
| 441 |
#endif |
| 442 |
/* add in untested sources */ |
| 443 |
for ( ; sn < ncnts; sn++) { |
| 444 |
scp = srccnt + cntord[sn].sndx; |
| 445 |
prob = hwt * (double)source[scp->sno].nhits / |
| 446 |
(double)source[scp->sno].ntests; |
| 447 |
if (prob > 1.0) |
| 448 |
prob = 1.0; |
| 449 |
scalecolor(scp->val, prob); |
| 450 |
addcolor(r->rcol, scp->val); |
| 451 |
} |
| 452 |
} |
| 453 |
|
| 454 |
|
| 455 |
void |
| 456 |
srcscatter( /* compute source scattering into ray */ |
| 457 |
register RAY *r |
| 458 |
) |
| 459 |
{ |
| 460 |
int oldsampndx; |
| 461 |
int nsamps; |
| 462 |
RAY sr; |
| 463 |
SRCINDEX si; |
| 464 |
double t, d; |
| 465 |
double re, ge, be; |
| 466 |
COLOR cvext; |
| 467 |
int i, j; |
| 468 |
|
| 469 |
if (r->slights == NULL || r->slights[0] == 0 |
| 470 |
|| r->gecc >= 1.-FTINY || r->rot >= FHUGE) |
| 471 |
return; |
| 472 |
if (ssampdist <= FTINY || (nsamps = r->rot/ssampdist + .5) < 1) |
| 473 |
nsamps = 1; |
| 474 |
#if MAXSSAMP |
| 475 |
else if (nsamps > MAXSSAMP) |
| 476 |
nsamps = MAXSSAMP; |
| 477 |
#endif |
| 478 |
oldsampndx = samplendx; |
| 479 |
samplendx = random()&0x7fff; /* randomize */ |
| 480 |
for (i = r->slights[0]; i > 0; i--) { /* for each source */ |
| 481 |
for (j = 0; j < nsamps; j++) { /* for each sample position */ |
| 482 |
samplendx++; |
| 483 |
t = r->rot * (j+frandom())/nsamps; |
| 484 |
/* extinction */ |
| 485 |
re = t*colval(r->cext,RED); |
| 486 |
ge = t*colval(r->cext,GRN); |
| 487 |
be = t*colval(r->cext,BLU); |
| 488 |
setcolor(cvext, re > 92. ? 0. : exp(-re), |
| 489 |
ge > 92. ? 0. : exp(-ge), |
| 490 |
be > 92. ? 0. : exp(-be)); |
| 491 |
if (intens(cvext) <= FTINY) |
| 492 |
break; /* too far away */ |
| 493 |
sr.rorg[0] = r->rorg[0] + r->rdir[0]*t; |
| 494 |
sr.rorg[1] = r->rorg[1] + r->rdir[1]*t; |
| 495 |
sr.rorg[2] = r->rorg[2] + r->rdir[2]*t; |
| 496 |
sr.rmax = 0.; |
| 497 |
initsrcindex(&si); /* sample ray to this source */ |
| 498 |
si.sn = r->slights[i]; |
| 499 |
nopart(&si, &sr); |
| 500 |
if (!srcray(&sr, NULL, &si) || |
| 501 |
sr.rsrc != r->slights[i]) |
| 502 |
continue; /* no path */ |
| 503 |
copycolor(sr.cext, r->cext); |
| 504 |
copycolor(sr.albedo, r->albedo); |
| 505 |
sr.gecc = r->gecc; |
| 506 |
sr.slights = r->slights; |
| 507 |
rayvalue(&sr); /* eval. source ray */ |
| 508 |
if (bright(sr.rcol) <= FTINY) |
| 509 |
continue; |
| 510 |
if (r->gecc <= FTINY) /* compute P(theta) */ |
| 511 |
d = 1.; |
| 512 |
else { |
| 513 |
d = DOT(r->rdir, sr.rdir); |
| 514 |
d = 1. + r->gecc*r->gecc - 2.*r->gecc*d; |
| 515 |
d = (1. - r->gecc*r->gecc) / (d*sqrt(d)); |
| 516 |
} |
| 517 |
/* other factors */ |
| 518 |
d *= si.dom * r->rot / (4.*PI*nsamps); |
| 519 |
multcolor(sr.rcol, r->cext); |
| 520 |
multcolor(sr.rcol, r->albedo); |
| 521 |
scalecolor(sr.rcol, d); |
| 522 |
multcolor(sr.rcol, cvext); |
| 523 |
addcolor(r->rcol, sr.rcol); /* add it in */ |
| 524 |
} |
| 525 |
} |
| 526 |
samplendx = oldsampndx; |
| 527 |
} |
| 528 |
|
| 529 |
|
| 530 |
/**************************************************************** |
| 531 |
* The following macros were separated from the m_light() routine |
| 532 |
* because they are very nasty and difficult to understand. |
| 533 |
*/ |
| 534 |
|
| 535 |
/* illumblock * |
| 536 |
* |
| 537 |
* We cannot allow an illum to pass to another illum, because that |
| 538 |
* would almost certainly constitute overcounting. |
| 539 |
* However, we do allow an illum to pass to another illum |
| 540 |
* that is actually going to relay to a virtual light source. |
| 541 |
* We also prevent an illum from passing to a glow; this provides a |
| 542 |
* convenient mechanism for defining detailed light source |
| 543 |
* geometry behind (or inside) an effective radiator. |
| 544 |
*/ |
| 545 |
|
| 546 |
static int |
| 547 |
weaksrcmat(int obj) /* identify material */ |
| 548 |
{ |
| 549 |
register OBJREC *o = objptr(obj); |
| 550 |
|
| 551 |
while (!ismaterial(o->otype)) /* find material */ |
| 552 |
o = objptr(o->omod); |
| 553 |
return((o->otype==MAT_ILLUM)|(o->otype==MAT_GLOW)); |
| 554 |
} |
| 555 |
|
| 556 |
#define illumblock(m, r) (!(source[r->rsrc].sflags&SVIRTUAL) && \ |
| 557 |
r->rod > 0.0 && \ |
| 558 |
weaksrcmat(source[r->rsrc].so->omod)) |
| 559 |
|
| 560 |
/* wrongsource * |
| 561 |
* |
| 562 |
* This source is the wrong source (ie. overcounted) if we are |
| 563 |
* aimed to a different source than the one we hit and the one |
| 564 |
* we hit is not an illum that should be passed. |
| 565 |
*/ |
| 566 |
|
| 567 |
#define wrongsource(m, r) (r->rsrc>=0 && source[r->rsrc].so!=r->ro && \ |
| 568 |
(m->otype!=MAT_ILLUM || illumblock(m,r))) |
| 569 |
|
| 570 |
/* distglow * |
| 571 |
* |
| 572 |
* A distant glow is an object that sometimes acts as a light source, |
| 573 |
* but is too far away from the test point to be one in this case. |
| 574 |
* (Glows with negative radii should NEVER participate in illumination.) |
| 575 |
*/ |
| 576 |
|
| 577 |
#define distglow(m, r, d) (m->otype==MAT_GLOW && \ |
| 578 |
m->oargs.farg[3] >= -FTINY && \ |
| 579 |
d > m->oargs.farg[3]) |
| 580 |
|
| 581 |
/* badcomponent * |
| 582 |
* |
| 583 |
* We must avoid counting light sources in the ambient calculation, |
| 584 |
* since the direct component is handled separately. Therefore, any |
| 585 |
* ambient ray which hits an active light source must be discarded. |
| 586 |
* The same is true for stray specular samples, since the specular |
| 587 |
* contribution from light sources is calculated separately. |
| 588 |
*/ |
| 589 |
|
| 590 |
#define badcomponent(m, r) (r->crtype&(AMBIENT|SPECULAR) && \ |
| 591 |
!(r->crtype&SHADOW || r->rod < 0.0 || \ |
| 592 |
/* not 100% correct */ distglow(m, r, r->rot))) |
| 593 |
|
| 594 |
/* passillum * |
| 595 |
* |
| 596 |
* An illum passes to another material type when we didn't hit it |
| 597 |
* on purpose (as part of a direct calculation), or it is relaying |
| 598 |
* a virtual light source. |
| 599 |
*/ |
| 600 |
|
| 601 |
#define passillum(m, r) (m->otype==MAT_ILLUM && \ |
| 602 |
(r->rsrc<0 || source[r->rsrc].so!=r->ro || \ |
| 603 |
source[r->rsrc].sflags&SVIRTUAL)) |
| 604 |
|
| 605 |
/* srcignore * |
| 606 |
* |
| 607 |
* The -dv flag is normally on for sources to be visible. |
| 608 |
*/ |
| 609 |
|
| 610 |
#define srcignore(m, r) !(directvis || r->crtype&SHADOW || \ |
| 611 |
distglow(m, r, raydist(r,PRIMARY))) |
| 612 |
|
| 613 |
|
| 614 |
int |
| 615 |
m_light( /* ray hit a light source */ |
| 616 |
register OBJREC *m, |
| 617 |
register RAY *r |
| 618 |
) |
| 619 |
{ |
| 620 |
/* check for over-counting */ |
| 621 |
if (badcomponent(m, r)) |
| 622 |
return(1); |
| 623 |
if (wrongsource(m, r)) |
| 624 |
return(1); |
| 625 |
/* check for passed illum */ |
| 626 |
if (passillum(m, r)) { |
| 627 |
if (m->oargs.nsargs && strcmp(m->oargs.sarg[0], VOIDID)) |
| 628 |
return(rayshade(r,lastmod(objndx(m),m->oargs.sarg[0]))); |
| 629 |
raytrans(r); |
| 630 |
return(1); |
| 631 |
} |
| 632 |
/* otherwise treat as source */ |
| 633 |
/* check for behind */ |
| 634 |
if (r->rod < 0.0) |
| 635 |
return(1); |
| 636 |
/* check for invisibility */ |
| 637 |
if (srcignore(m, r)) |
| 638 |
return(1); |
| 639 |
/* check for outside spot */ |
| 640 |
if (m->otype==MAT_SPOT && spotout(r, makespot(m))) |
| 641 |
return(1); |
| 642 |
/* get distribution pattern */ |
| 643 |
raytexture(r, m->omod); |
| 644 |
/* get source color */ |
| 645 |
setcolor(r->rcol, m->oargs.farg[0], |
| 646 |
m->oargs.farg[1], |
| 647 |
m->oargs.farg[2]); |
| 648 |
/* modify value */ |
| 649 |
multcolor(r->rcol, r->pcol); |
| 650 |
return(1); |
| 651 |
} |
