ViewVC Help
View File | Revision Log | Show Annotations | Download File | Root Listing
root/radiance/ray/src/rt/source.c
Revision: 2.20
Committed: Sat Dec 9 11:30:19 1995 UTC (28 years, 4 months ago) by greg
Content type: text/plain
Branch: MAIN
Changes since 2.19: +4 -0 lines
Log Message:
fixed handling of samplendx in srcscatter()

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