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root/radiance/ray/src/rt/source.c
Revision: 2.27
Committed: Fri Aug 15 10:24:24 1997 UTC (26 years, 8 months ago) by gregl
Content type: text/plain
Branch: MAIN
Changes since 2.26: +1 -0 lines
Log Message:
added setting of r->robj for rv2.c

File Contents

# Content
1 /* Copyright (c) 1995 Regents of the University of California */
2
3 #ifndef lint
4 static char SCCSid[] = "$SunId$ LBL";
5 #endif
6
7 /*
8 * source.c - routines dealing with illumination sources.
9 *
10 * 8/20/85
11 */
12
13 #include "ray.h"
14
15 #include "octree.h"
16
17 #include "otypes.h"
18
19 #include "source.h"
20
21 #include "random.h"
22
23 extern double ssampdist; /* scatter sampling distance */
24
25 #ifndef MAXSSAMP
26 #define MAXSSAMP 16 /* maximum samples per ray */
27 #endif
28
29 /*
30 * Structures used by direct()
31 */
32
33 typedef struct {
34 int sno; /* source number */
35 FVECT dir; /* source direction */
36 COLOR coef; /* material coefficient */
37 COLOR val; /* contribution */
38 } CONTRIB; /* direct contribution */
39
40 typedef struct {
41 int sndx; /* source index (to CONTRIB array) */
42 float brt; /* brightness (for comparison) */
43 } CNTPTR; /* contribution pointer */
44
45 static CONTRIB *srccnt; /* source contributions in direct() */
46 static CNTPTR *cntord; /* source ordering in direct() */
47 static int maxcntr = 0; /* size of contribution arrays */
48
49
50 marksources() /* find and mark source objects */
51 {
52 int foundsource = 0;
53 int i;
54 register OBJREC *o, *m;
55 register int ns;
56 /* initialize dispatch table */
57 initstypes();
58 /* find direct sources */
59 for (i = 0; i < nobjects; i++) {
60
61 o = objptr(i);
62
63 if (!issurface(o->otype) || o->omod == OVOID)
64 continue;
65
66 m = objptr(o->omod);
67
68 if (!islight(m->otype))
69 continue;
70
71 if (m->oargs.nfargs != (m->otype == MAT_GLOW ? 4 :
72 m->otype == MAT_SPOT ? 7 : 3))
73 objerror(m, USER, "bad # arguments");
74
75 if (m->otype == MAT_GLOW &&
76 o->otype != OBJ_SOURCE &&
77 m->oargs.farg[3] <= FTINY)
78 continue; /* don't bother */
79 if (m->oargs.farg[0] <= FTINY && m->oargs.farg[1] <= FTINY &&
80 m->oargs.farg[2] <= FTINY)
81 continue; /* don't bother */
82
83 if (sfun[o->otype].of == NULL ||
84 sfun[o->otype].of->setsrc == NULL)
85 objerror(o, USER, "illegal material");
86
87 if ((ns = newsource()) < 0)
88 goto memerr;
89
90 setsource(&source[ns], o);
91
92 if (m->otype == MAT_GLOW) {
93 source[ns].sflags |= SPROX;
94 source[ns].sl.prox = m->oargs.farg[3];
95 if (source[ns].sflags & SDISTANT)
96 source[ns].sflags |= SSKIP;
97 } else if (m->otype == MAT_SPOT) {
98 source[ns].sflags |= SSPOT;
99 if ((source[ns].sl.s = makespot(m)) == NULL)
100 goto memerr;
101 if (source[ns].sflags & SFLAT &&
102 !checkspot(source[ns].sl.s,source[ns].snorm)) {
103 objerror(o, WARNING,
104 "invalid spotlight direction");
105 source[ns].sflags |= SSKIP;
106 }
107 }
108 if (!(source[ns].sflags & SSKIP))
109 foundsource++;
110 }
111 if (!foundsource) {
112 error(WARNING, "no light sources found");
113 return;
114 }
115 markvirtuals(); /* find and add virtual sources */
116 /* allocate our contribution arrays */
117 maxcntr = nsources + MAXSPART; /* start with this many */
118 srccnt = (CONTRIB *)malloc(maxcntr*sizeof(CONTRIB));
119 cntord = (CNTPTR *)malloc(maxcntr*sizeof(CNTPTR));
120 if (srccnt == NULL | cntord == NULL)
121 goto memerr;
122 return;
123 memerr:
124 error(SYSTEM, "out of memory in marksources");
125 }
126
127
128 srcray(sr, r, si) /* send a ray to a source, return domega */
129 register RAY *sr; /* returned source ray */
130 RAY *r; /* ray which hit object */
131 SRCINDEX *si; /* source sample index */
132 {
133 double d; /* distance to source */
134 register SRCREC *srcp;
135
136 rayorigin(sr, r, SHADOW, 1.0); /* ignore limits */
137
138 while ((d = nextssamp(sr, si)) != 0.0) {
139 sr->rsrc = si->sn; /* remember source */
140 srcp = source + si->sn;
141 if (srcp->sflags & SDISTANT) {
142 if (srcp->sflags & SSPOT && spotout(sr, srcp->sl.s))
143 continue;
144 return(1); /* sample OK */
145 }
146 /* local source */
147 /* check proximity */
148 if (srcp->sflags & SPROX && d > srcp->sl.prox)
149 continue;
150 /* check angle */
151 if (srcp->sflags & SSPOT) {
152 if (spotout(sr, srcp->sl.s))
153 continue;
154 /* adjust solid angle */
155 si->dom *= d*d;
156 d += srcp->sl.s->flen;
157 si->dom /= d*d;
158 }
159 return(1); /* sample OK */
160 }
161 return(0); /* no more samples */
162 }
163
164
165 srcvalue(r) /* punch ray to source and compute value */
166 register RAY *r;
167 {
168 register SRCREC *sp;
169
170 sp = &source[r->rsrc];
171 if (sp->sflags & SVIRTUAL) { /* virtual source */
172 /* check intersection */
173 if (!(*ofun[sp->so->otype].funp)(sp->so, r))
174 return;
175 if (!rayshade(r, r->ro->omod)) /* compute contribution */
176 goto nomat;
177 rayparticipate(r);
178 return;
179 }
180 /* compute intersection */
181 if (sp->sflags & SDISTANT ? sourcehit(r) :
182 (*ofun[sp->so->otype].funp)(sp->so, r)) {
183 if (sp->sa.success >= 0)
184 sp->sa.success++;
185 if (!rayshade(r, r->ro->omod)) /* compute contribution */
186 goto nomat;
187 rayparticipate(r);
188 return;
189 }
190 /* we missed our mark! */
191 if (sp->sa.success < 0)
192 return; /* bitched already */
193 sp->sa.success -= AIMREQT;
194 if (sp->sa.success >= 0)
195 return; /* leniency */
196 sprintf(errmsg, "aiming failure for light source \"%s\"",
197 sp->so->oname);
198 error(WARNING, errmsg); /* issue warning */
199 return;
200 nomat:
201 objerror(r->ro, USER, "material not found");
202 }
203
204
205 sourcehit(r) /* check to see if ray hit distant source */
206 register RAY *r;
207 {
208 int first, last;
209 register int i;
210
211 if (r->rsrc >= 0) { /* check only one if aimed */
212 first = last = r->rsrc;
213 } else { /* otherwise check all */
214 first = 0; last = nsources-1;
215 }
216 for (i = first; i <= last; i++)
217 if ((source[i].sflags & (SDISTANT|SVIRTUAL)) == SDISTANT)
218 /*
219 * Check to see if ray is within
220 * solid angle of source.
221 */
222 if (2.0*PI * (1.0 - DOT(source[i].sloc,r->rdir))
223 <= source[i].ss2) {
224 r->ro = source[i].so;
225 if (!(source[i].sflags & SSKIP))
226 break;
227 }
228
229 if (r->ro != NULL) {
230 r->robj = objndx(r->ro);
231 for (i = 0; i < 3; i++)
232 r->ron[i] = -r->rdir[i];
233 r->rod = 1.0;
234 r->rox = NULL;
235 return(1);
236 }
237 return(0);
238 }
239
240
241 static int
242 cntcmp(sc1, sc2) /* contribution compare (descending) */
243 register CNTPTR *sc1, *sc2;
244 {
245 if (sc1->brt > sc2->brt)
246 return(-1);
247 if (sc1->brt < sc2->brt)
248 return(1);
249 return(0);
250 }
251
252
253 direct(r, f, p) /* add direct component */
254 RAY *r; /* ray that hit surface */
255 int (*f)(); /* direct component coefficient function */
256 char *p; /* data for f */
257 {
258 extern int (*trace)();
259 register int sn;
260 register CONTRIB *scp;
261 SRCINDEX si;
262 int nshadcheck, ncnts;
263 int nhits;
264 double prob, ourthresh, hwt;
265 RAY sr;
266 /* NOTE: srccnt and cntord global so no recursion */
267 if (nsources <= 0)
268 return; /* no sources?! */
269 /* potential contributions */
270 initsrcindex(&si);
271 for (sn = 0; srcray(&sr, r, &si); sn++) {
272 if (sn >= maxcntr) {
273 maxcntr = sn + MAXSPART;
274 srccnt = (CONTRIB *)realloc((char *)srccnt,
275 maxcntr*sizeof(CONTRIB));
276 cntord = (CNTPTR *)realloc((char *)cntord,
277 maxcntr*sizeof(CNTPTR));
278 if (srccnt == NULL | cntord == NULL)
279 error(SYSTEM, "out of memory in direct");
280 }
281 cntord[sn].sndx = sn;
282 scp = srccnt + sn;
283 scp->sno = sr.rsrc;
284 /* compute coefficient */
285 (*f)(scp->coef, p, sr.rdir, si.dom);
286 cntord[sn].brt = bright(scp->coef);
287 if (cntord[sn].brt <= 0.0)
288 continue;
289 VCOPY(scp->dir, sr.rdir);
290 /* compute potential */
291 sr.revf = srcvalue;
292 rayvalue(&sr);
293 copycolor(scp->val, sr.rcol);
294 multcolor(scp->val, scp->coef);
295 cntord[sn].brt = bright(scp->val);
296 }
297 /* sort contributions */
298 qsort(cntord, sn, sizeof(CNTPTR), cntcmp);
299 { /* find last */
300 register int l, m;
301
302 ncnts = l = sn;
303 sn = 0;
304 while ((m = (sn + ncnts) >> 1) != l) {
305 if (cntord[m].brt > 0.0)
306 sn = m;
307 else
308 ncnts = m;
309 l = m;
310 }
311 }
312 if (ncnts == 0)
313 return; /* no contributions! */
314 /* accumulate tail */
315 for (sn = ncnts-1; sn > 0; sn--)
316 cntord[sn-1].brt += cntord[sn].brt;
317 /* compute number to check */
318 nshadcheck = pow((double)ncnts, shadcert) + .5;
319 /* modify threshold */
320 ourthresh = shadthresh / r->rweight;
321 /* test for shadows */
322 for (nhits = 0, hwt = 0.0, sn = 0; sn < ncnts;
323 hwt += (double)source[scp->sno].nhits /
324 (double)source[scp->sno].ntests,
325 sn++) {
326 /* check threshold */
327 if ((sn+nshadcheck>=ncnts ? cntord[sn].brt :
328 cntord[sn].brt-cntord[sn+nshadcheck].brt)
329 < ourthresh*bright(r->rcol))
330 break;
331 scp = srccnt + cntord[sn].sndx;
332 /* test for hit */
333 rayorigin(&sr, r, SHADOW, 1.0);
334 VCOPY(sr.rdir, scp->dir);
335 sr.rsrc = scp->sno;
336 source[scp->sno].ntests++; /* keep statistics */
337 if (localhit(&sr, &thescene) &&
338 ( sr.ro != source[scp->sno].so ||
339 source[scp->sno].sflags & SFOLLOW )) {
340 /* follow entire path */
341 raycont(&sr);
342 rayparticipate(&sr);
343 if (trace != NULL)
344 (*trace)(&sr); /* trace execution */
345 if (bright(sr.rcol) <= FTINY)
346 continue; /* missed! */
347 copycolor(scp->val, sr.rcol);
348 multcolor(scp->val, scp->coef);
349 }
350 /* add contribution if hit */
351 addcolor(r->rcol, scp->val);
352 nhits++;
353 source[scp->sno].nhits++;
354 }
355 /* source hit rate */
356 if (hwt > FTINY)
357 hwt = (double)nhits / hwt;
358 else
359 hwt = 0.5;
360 #ifdef DEBUG
361 sprintf(errmsg, "%d tested, %d untested, %f conditional hit rate\n",
362 sn, ncnts-sn, hwt);
363 eputs(errmsg);
364 #endif
365 /* add in untested sources */
366 for ( ; sn < ncnts; sn++) {
367 scp = srccnt + cntord[sn].sndx;
368 prob = hwt * (double)source[scp->sno].nhits /
369 (double)source[scp->sno].ntests;
370 if (prob > 1.0)
371 prob = 1.0;
372 scalecolor(scp->val, prob);
373 addcolor(r->rcol, scp->val);
374 }
375 }
376
377
378 srcscatter(r) /* compute source scattering into ray */
379 register RAY *r;
380 {
381 int oldsampndx;
382 int nsamps;
383 RAY sr;
384 SRCINDEX si;
385 double t, d;
386 double re, ge, be;
387 COLOR cvext;
388 int i, j;
389
390 if (r->slights == NULL || r->slights[0] == 0
391 || r->gecc >= 1.-FTINY || r->rot >= FHUGE)
392 return;
393 if (ssampdist <= FTINY || (nsamps = r->rot/ssampdist + .5) < 1)
394 nsamps = 1;
395 #if MAXSSAMP
396 else if (nsamps > MAXSSAMP)
397 nsamps = MAXSSAMP;
398 #endif
399 oldsampndx = samplendx;
400 samplendx = random()&0x7fff; /* randomize */
401 for (i = r->slights[0]; i > 0; i--) { /* for each source */
402 for (j = 0; j < nsamps; j++) { /* for each sample position */
403 samplendx++;
404 t = r->rot * (j+frandom())/nsamps;
405 /* extinction */
406 re = t*colval(r->cext,RED);
407 ge = t*colval(r->cext,GRN);
408 be = t*colval(r->cext,BLU);
409 setcolor(cvext, re > 92. ? 0. : exp(-re),
410 ge > 92. ? 0. : exp(-ge),
411 be > 92. ? 0. : exp(-be));
412 if (intens(cvext) <= FTINY)
413 break; /* too far away */
414 sr.rorg[0] = r->rorg[0] + r->rdir[0]*t;
415 sr.rorg[1] = r->rorg[1] + r->rdir[1]*t;
416 sr.rorg[2] = r->rorg[2] + r->rdir[2]*t;
417 sr.rmax = 0.;
418 initsrcindex(&si); /* sample ray to this source */
419 si.sn = r->slights[i];
420 nopart(&si, &sr);
421 if (!srcray(&sr, NULL, &si) ||
422 sr.rsrc != r->slights[i])
423 continue; /* no path */
424 copycolor(sr.cext, r->cext);
425 copycolor(sr.albedo, r->albedo);
426 sr.gecc = r->gecc;
427 sr.slights = r->slights;
428 rayvalue(&sr); /* eval. source ray */
429 if (bright(sr.rcol) <= FTINY)
430 continue;
431 if (r->gecc <= FTINY) /* compute P(theta) */
432 d = 1.;
433 else {
434 d = DOT(r->rdir, sr.rdir);
435 d = 1. + r->gecc*r->gecc - 2.*r->gecc*d;
436 d = (1. - r->gecc*r->gecc) / (d*sqrt(d));
437 }
438 /* other factors */
439 d *= si.dom * r->rot / (4.*PI*nsamps);
440 multcolor(sr.rcol, r->cext);
441 multcolor(sr.rcol, r->albedo);
442 scalecolor(sr.rcol, d);
443 multcolor(sr.rcol, cvext);
444 addcolor(r->rcol, sr.rcol); /* add it in */
445 }
446 }
447 samplendx = oldsampndx;
448 }
449
450
451 /****************************************************************
452 * The following macros were separated from the m_light() routine
453 * because they are very nasty and difficult to understand.
454 */
455
456 /* illumblock *
457 *
458 * We cannot allow an illum to pass to another illum, because that
459 * would almost certainly constitute overcounting.
460 * However, we do allow an illum to pass to another illum
461 * that is actually going to relay to a virtual light source.
462 * We also prevent an illum from passing to a glow; this provides a
463 * convenient mechanism for defining detailed light source
464 * geometry behind (or inside) an effective radiator.
465 */
466
467 static int weaksrcmod(obj) int obj; /* efficiency booster function */
468 {register OBJREC *o = objptr(obj);
469 return(o->otype==MAT_ILLUM|o->otype==MAT_GLOW);}
470
471 #define illumblock(m, r) (!(source[r->rsrc].sflags&SVIRTUAL) && \
472 r->rod > 0.0 && \
473 weaksrcmod(source[r->rsrc].so->omod))
474
475 /* wrongsource *
476 *
477 * This source is the wrong source (ie. overcounted) if we are
478 * aimed to a different source than the one we hit and the one
479 * we hit is not an illum that should be passed.
480 */
481
482 #define wrongsource(m, r) (r->rsrc>=0 && source[r->rsrc].so!=r->ro && \
483 (m->otype!=MAT_ILLUM || illumblock(m,r)))
484
485 /* distglow *
486 *
487 * A distant glow is an object that sometimes acts as a light source,
488 * but is too far away from the test point to be one in this case.
489 * (Glows with negative radii should NEVER participate in illumination.)
490 */
491
492 #define distglow(m, r, d) (m->otype==MAT_GLOW && \
493 m->oargs.farg[3] >= -FTINY && \
494 d > m->oargs.farg[3])
495
496 /* badcomponent *
497 *
498 * We must avoid counting light sources in the ambient calculation,
499 * since the direct component is handled separately. Therefore, any
500 * ambient ray which hits an active light source must be discarded.
501 * The same is true for stray specular samples, since the specular
502 * contribution from light sources is calculated separately.
503 */
504
505 #define badcomponent(m, r) (r->crtype&(AMBIENT|SPECULAR) && \
506 !(r->crtype&SHADOW || r->rod < 0.0 || \
507 /* not 100% correct */ distglow(m, r, r->rot)))
508
509 /* passillum *
510 *
511 * An illum passes to another material type when we didn't hit it
512 * on purpose (as part of a direct calculation), or it is relaying
513 * a virtual light source.
514 */
515
516 #define passillum(m, r) (m->otype==MAT_ILLUM && \
517 (r->rsrc<0 || source[r->rsrc].so!=r->ro || \
518 source[r->rsrc].sflags&SVIRTUAL))
519
520 /* srcignore *
521 *
522 * The -dv flag is normally on for sources to be visible.
523 */
524
525 #define srcignore(m, r) !(directvis || r->crtype&SHADOW || \
526 distglow(m, r, raydist(r,PRIMARY)))
527
528
529 m_light(m, r) /* ray hit a light source */
530 register OBJREC *m;
531 register RAY *r;
532 {
533 /* check for over-counting */
534 if (badcomponent(m, r))
535 return(1);
536 if (wrongsource(m, r))
537 return(1);
538 /* check for passed illum */
539 if (passillum(m, r)) {
540 if (m->oargs.nsargs && strcmp(m->oargs.sarg[0], VOIDID))
541 return(rayshade(r, modifier(m->oargs.sarg[0])));
542 raytrans(r);
543 return(1);
544 }
545 /* otherwise treat as source */
546 /* check for behind */
547 if (r->rod < 0.0)
548 return(1);
549 /* check for invisibility */
550 if (srcignore(m, r))
551 return(1);
552 /* check for outside spot */
553 if (m->otype==MAT_SPOT && spotout(r, makespot(m)))
554 return(1);
555 /* get distribution pattern */
556 raytexture(r, m->omod);
557 /* get source color */
558 setcolor(r->rcol, m->oargs.farg[0],
559 m->oargs.farg[1],
560 m->oargs.farg[2]);
561 /* modify value */
562 multcolor(r->rcol, r->pcol);
563 return(1);
564 }