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root/radiance/ray/src/rt/source.c
Revision: 2.63
Committed: Mon Sep 15 00:54:39 2014 UTC (9 years, 7 months ago) by greg
Content type: text/plain
Branch: MAIN
CVS Tags: rad4R2P2, rad4R2P1
Changes since 2.62: +5 -2 lines
Log Message:
Set minimum number of shadow checks to perform (4)

File Contents

# User Rev Content
1 greg 1.1 #ifndef lint
2 greg 2.63 static const char RCSid[] = "$Id: source.c,v 2.62 2014/05/07 02:08:12 greg Exp $";
3 greg 1.1 #endif
4     /*
5     * source.c - routines dealing with illumination sources.
6     *
7 greg 2.29 * External symbols declared in source.h
8     */
9    
10 greg 1.1 #include "ray.h"
11     #include "otypes.h"
12 schorsch 2.44 #include "rtotypes.h"
13 greg 1.35 #include "source.h"
14 greg 2.19 #include "random.h"
15    
16 greg 2.22 #ifndef MAXSSAMP
17     #define MAXSSAMP 16 /* maximum samples per ray */
18     #endif
19    
20 greg 1.35 /*
21     * Structures used by direct()
22     */
23 greg 1.1
24 greg 1.35 typedef struct {
25 greg 1.45 int sno; /* source number */
26 greg 1.35 FVECT dir; /* source direction */
27     COLOR coef; /* material coefficient */
28     COLOR val; /* contribution */
29     } CONTRIB; /* direct contribution */
30 greg 1.1
31 greg 1.35 typedef struct {
32 greg 1.45 int sndx; /* source index (to CONTRIB array) */
33 greg 1.35 float brt; /* brightness (for comparison) */
34     } CNTPTR; /* contribution pointer */
35 greg 1.1
36 greg 1.25 static CONTRIB *srccnt; /* source contributions in direct() */
37     static CNTPTR *cntord; /* source ordering in direct() */
38 greg 1.45 static int maxcntr = 0; /* size of contribution arrays */
39 greg 1.1
40 schorsch 2.44 static int cntcmp(const void *p1, const void *p2);
41    
42 greg 1.25
43 greg 2.62 OBJREC * /* find an object's actual material */
44     findmaterial(OBJREC *o)
45 greg 2.38 {
46     while (!ismaterial(o->otype)) {
47     if (o->otype == MOD_ALIAS && o->oargs.nsargs) {
48     OBJECT aobj;
49     OBJREC *ao;
50     aobj = lastmod(objndx(o), o->oargs.sarg[0]);
51     if (aobj < 0)
52     objerror(o, USER, "bad reference");
53     ao = objptr(aobj);
54     if (ismaterial(ao->otype))
55     return(ao);
56 greg 2.54 if (ao->otype == MOD_ALIAS) {
57     o = ao;
58     continue;
59     }
60 greg 2.38 }
61     if (o->omod == OVOID)
62     return(NULL);
63     o = objptr(o->omod);
64     }
65 greg 2.48 return(o); /* mixtures will return NULL */
66 greg 2.38 }
67    
68    
69 greg 2.62 void
70 schorsch 2.44 marksources(void) /* find and mark source objects */
71 greg 1.1 {
72 greg 2.3 int foundsource = 0;
73 greg 1.33 int i;
74 greg 2.62 OBJREC *o, *m;
75     int ns;
76 greg 1.35 /* initialize dispatch table */
77     initstypes();
78     /* find direct sources */
79 greg 2.33 for (i = 0; i < nsceneobjs; i++) {
80 greg 1.1
81     o = objptr(i);
82    
83 greg 1.35 if (!issurface(o->otype) || o->omod == OVOID)
84 greg 1.1 continue;
85 greg 2.36 /* find material */
86 greg 2.43 m = findmaterial(objptr(o->omod));
87 greg 2.56 if (m == NULL)
88     continue;
89     if (m->otype == MAT_CLIP) {
90     markclip(m); /* special case for antimatter */
91     continue;
92     }
93     if (!islight(m->otype))
94 greg 2.36 continue; /* not source modifier */
95 greg 1.1
96 greg 1.6 if (m->oargs.nfargs != (m->otype == MAT_GLOW ? 4 :
97     m->otype == MAT_SPOT ? 7 : 3))
98 greg 1.1 objerror(m, USER, "bad # arguments");
99    
100 greg 2.16 if (m->oargs.farg[0] <= FTINY && m->oargs.farg[1] <= FTINY &&
101     m->oargs.farg[2] <= FTINY)
102     continue; /* don't bother */
103 greg 2.61 if (m->otype == MAT_GLOW &&
104     o->otype != OBJ_SOURCE &&
105     m->oargs.farg[3] <= FTINY) {
106     foundsource += (ambounce > 0);
107     continue; /* don't track these */
108     }
109 greg 1.35 if (sfun[o->otype].of == NULL ||
110     sfun[o->otype].of->setsrc == NULL)
111     objerror(o, USER, "illegal material");
112    
113 greg 1.36 if ((ns = newsource()) < 0)
114 greg 1.25 goto memerr;
115 greg 1.1
116 greg 1.37 setsource(&source[ns], o);
117 greg 1.1
118 greg 1.6 if (m->otype == MAT_GLOW) {
119 greg 1.36 source[ns].sflags |= SPROX;
120     source[ns].sl.prox = m->oargs.farg[3];
121 greg 2.61 if (source[ns].sflags & SDISTANT) {
122 greg 1.36 source[ns].sflags |= SSKIP;
123 greg 2.61 foundsource += (ambounce > 0);
124     }
125 greg 1.6 } else if (m->otype == MAT_SPOT) {
126 greg 1.36 source[ns].sflags |= SSPOT;
127     if ((source[ns].sl.s = makespot(m)) == NULL)
128 greg 1.33 goto memerr;
129 greg 1.38 if (source[ns].sflags & SFLAT &&
130     !checkspot(source[ns].sl.s,source[ns].snorm)) {
131     objerror(o, WARNING,
132     "invalid spotlight direction");
133     source[ns].sflags |= SSKIP;
134     }
135 greg 1.6 }
136 greg 2.38 #if SHADCACHE
137 greg 2.46 initobscache(ns);
138 greg 2.38 #endif
139 greg 2.61 foundsource += !(source[ns].sflags & SSKIP);
140 greg 1.1 }
141 greg 2.3 if (!foundsource) {
142 greg 1.25 error(WARNING, "no light sources found");
143     return;
144     }
145 greg 1.33 markvirtuals(); /* find and add virtual sources */
146 greg 1.45 /* allocate our contribution arrays */
147 greg 1.48 maxcntr = nsources + MAXSPART; /* start with this many */
148 greg 1.45 srccnt = (CONTRIB *)malloc(maxcntr*sizeof(CONTRIB));
149     cntord = (CNTPTR *)malloc(maxcntr*sizeof(CNTPTR));
150 schorsch 2.35 if ((srccnt == NULL) | (cntord == NULL))
151 greg 1.33 goto memerr;
152     return;
153 greg 1.25 memerr:
154     error(SYSTEM, "out of memory in marksources");
155 greg 1.1 }
156    
157    
158 greg 2.62 void
159 schorsch 2.44 freesources(void) /* free all source structures */
160 greg 2.29 {
161     if (nsources > 0) {
162 greg 2.38 #if SHADCACHE
163     while (nsources--)
164     freeobscache(&source[nsources]);
165     #endif
166 greg 2.29 free((void *)source);
167     source = NULL;
168     nsources = 0;
169     }
170 greg 2.60 markclip(NULL);
171 greg 2.29 if (maxcntr <= 0)
172     return;
173     free((void *)srccnt);
174     srccnt = NULL;
175     free((void *)cntord);
176     cntord = NULL;
177     maxcntr = 0;
178     }
179    
180    
181 greg 2.62 int
182 greg 2.38 srcray( /* send a ray to a source, return domega */
183 greg 2.62 RAY *sr, /* returned source ray */
184 schorsch 2.44 RAY *r, /* ray which hit object */
185     SRCINDEX *si /* source sample index */
186 greg 2.38 )
187 greg 1.1 {
188 greg 2.59 double d; /* distance to source */
189 greg 2.62 SRCREC *srcp;
190 greg 1.1
191 greg 2.59 rayorigin(sr, SHADOW, r, NULL); /* ignore limits */
192 greg 1.1
193 greg 2.59 if (r == NULL)
194     sr->rmax = 0.0;
195    
196     while ((d = nextssamp(sr, si)) != 0.0) {
197     sr->rsrc = si->sn; /* remember source */
198     srcp = source + si->sn;
199     if (srcp->sflags & SDISTANT) {
200     if (srcp->sflags & SSPOT && spotout(sr, srcp->sl.s))
201     continue;
202     return(1); /* sample OK */
203     }
204 greg 1.45 /* local source */
205 greg 1.6 /* check proximity */
206 greg 2.59 if (srcp->sflags & SPROX && d > srcp->sl.prox)
207     continue;
208 greg 1.6 /* check angle */
209 greg 2.59 if (srcp->sflags & SSPOT) {
210     if (spotout(sr, srcp->sl.s))
211     continue;
212 greg 1.45 /* adjust solid angle */
213 greg 2.59 si->dom *= d*d;
214     d += srcp->sl.s->flen;
215     si->dom /= d*d;
216     }
217     return(1); /* sample OK */
218     }
219     return(0); /* no more samples */
220 greg 1.1 }
221    
222    
223 greg 2.62 void
224 greg 2.38 srcvalue( /* punch ray to source and compute value */
225 greg 2.62 RAY *r
226 greg 2.38 )
227 greg 1.1 {
228 greg 2.62 SRCREC *sp;
229 greg 1.1
230 greg 1.35 sp = &source[r->rsrc];
231     if (sp->sflags & SVIRTUAL) { /* virtual source */
232     /* check intersection */
233     if (!(*ofun[sp->so->otype].funp)(sp->so, r))
234     return;
235 greg 2.15 if (!rayshade(r, r->ro->omod)) /* compute contribution */
236     goto nomat;
237 greg 2.19 rayparticipate(r);
238 greg 1.35 return;
239 greg 1.1 }
240 greg 1.35 /* compute intersection */
241     if (sp->sflags & SDISTANT ? sourcehit(r) :
242     (*ofun[sp->so->otype].funp)(sp->so, r)) {
243     if (sp->sa.success >= 0)
244     sp->sa.success++;
245 greg 2.15 if (!rayshade(r, r->ro->omod)) /* compute contribution */
246     goto nomat;
247 greg 2.19 rayparticipate(r);
248 greg 1.35 return;
249 greg 1.1 }
250 greg 2.15 /* we missed our mark! */
251 greg 1.35 if (sp->sa.success < 0)
252     return; /* bitched already */
253     sp->sa.success -= AIMREQT;
254     if (sp->sa.success >= 0)
255     return; /* leniency */
256     sprintf(errmsg, "aiming failure for light source \"%s\"",
257     sp->so->oname);
258     error(WARNING, errmsg); /* issue warning */
259 greg 2.15 return;
260     nomat:
261     objerror(r->ro, USER, "material not found");
262 greg 1.1 }
263    
264    
265 greg 2.47 static int
266     transillum( /* check if material is transparent illum */
267     OBJECT obj
268     )
269     {
270     OBJREC *m = findmaterial(objptr(obj));
271    
272     if (m == NULL)
273     return(1);
274     if (m->otype != MAT_ILLUM)
275     return(0);
276     return(!m->oargs.nsargs || !strcmp(m->oargs.sarg[0], VOIDID));
277     }
278    
279    
280 greg 2.62 int
281 greg 2.38 sourcehit( /* check to see if ray hit distant source */
282 greg 2.62 RAY *r
283 greg 2.38 )
284 greg 2.5 {
285 greg 2.47 int glowsrc = -1;
286     int transrc = -1;
287 greg 2.5 int first, last;
288 greg 2.62 int i;
289 greg 2.5
290     if (r->rsrc >= 0) { /* check only one if aimed */
291     first = last = r->rsrc;
292     } else { /* otherwise check all */
293     first = 0; last = nsources-1;
294     }
295 greg 2.47 for (i = first; i <= last; i++) {
296     if ((source[i].sflags & (SDISTANT|SVIRTUAL)) != SDISTANT)
297     continue;
298     /*
299     * Check to see if ray is within
300     * solid angle of source.
301     */
302     if (2.*PI*(1. - DOT(source[i].sloc,r->rdir)) > source[i].ss2)
303     continue;
304     /* is it the only possibility? */
305     if (first == last) {
306     r->ro = source[i].so;
307     break;
308     }
309     /*
310     * If it's a glow or transparent illum, just remember it.
311     */
312     if (source[i].sflags & SSKIP) {
313 greg 2.58 if (glowsrc < 0)
314     glowsrc = i;
315 greg 2.47 continue;
316     }
317     if (transillum(source[i].so->omod)) {
318 greg 2.58 if (transrc < 0)
319     transrc = i;
320 greg 2.47 continue;
321     }
322     r->ro = source[i].so; /* otherwise, use first hit */
323     break;
324 greg 2.5 }
325 greg 2.47 /*
326     * Do we need fallback?
327     */
328     if (r->ro == NULL) {
329     if (transrc >= 0 && r->crtype & (AMBIENT|SPECULAR))
330     return(0); /* avoid overcounting */
331     if (glowsrc >= 0)
332     r->ro = source[glowsrc].so;
333     else
334     return(0); /* nothing usable */
335     }
336     /*
337     * Make assignments.
338     */
339     r->robj = objndx(r->ro);
340     for (i = 0; i < 3; i++)
341     r->ron[i] = -r->rdir[i];
342     r->rod = 1.0;
343     r->pert[0] = r->pert[1] = r->pert[2] = 0.0;
344     r->uv[0] = r->uv[1] = 0.0;
345     r->rox = NULL;
346     return(1);
347 greg 2.5 }
348 greg 2.38
349    
350 greg 1.4 static int
351 greg 2.38 cntcmp( /* contribution compare (descending) */
352 schorsch 2.44 const void *p1,
353     const void *p2
354 greg 2.38 )
355 greg 1.4 {
356 greg 2.62 const CNTPTR *sc1 = (const CNTPTR *)p1;
357     const CNTPTR *sc2 = (const CNTPTR *)p2;
358 greg 2.38
359 greg 1.4 if (sc1->brt > sc2->brt)
360     return(-1);
361     if (sc1->brt < sc2->brt)
362     return(1);
363     return(0);
364     }
365    
366    
367 greg 2.62 void
368 greg 2.38 direct( /* add direct component */
369 schorsch 2.44 RAY *r, /* ray that hit surface */
370     srcdirf_t *f, /* direct component coefficient function */
371     void *p /* data for f */
372 greg 2.38 )
373 greg 1.4 {
374 greg 2.62 int sn;
375     CONTRIB *scp;
376 greg 1.45 SRCINDEX si;
377 greg 1.12 int nshadcheck, ncnts;
378 greg 1.29 int nhits;
379 greg 1.45 double prob, ourthresh, hwt;
380 greg 1.4 RAY sr;
381 greg 1.25 /* NOTE: srccnt and cntord global so no recursion */
382 greg 1.22 if (nsources <= 0)
383 greg 1.25 return; /* no sources?! */
384 greg 1.4 /* potential contributions */
385 greg 1.45 initsrcindex(&si);
386     for (sn = 0; srcray(&sr, r, &si); sn++) {
387     if (sn >= maxcntr) {
388     maxcntr = sn + MAXSPART;
389 greg 2.32 srccnt = (CONTRIB *)realloc((void *)srccnt,
390 greg 1.45 maxcntr*sizeof(CONTRIB));
391 greg 2.32 cntord = (CNTPTR *)realloc((void *)cntord,
392 greg 1.45 maxcntr*sizeof(CNTPTR));
393 schorsch 2.35 if ((srccnt == NULL) | (cntord == NULL))
394 greg 1.45 error(SYSTEM, "out of memory in direct");
395     }
396     cntord[sn].sndx = sn;
397 greg 2.7 scp = srccnt + sn;
398     scp->sno = sr.rsrc;
399 greg 1.4 /* compute coefficient */
400 greg 2.7 (*f)(scp->coef, p, sr.rdir, si.dom);
401 greg 2.53 cntord[sn].brt = intens(scp->coef);
402 greg 1.15 if (cntord[sn].brt <= 0.0)
403 greg 1.4 continue;
404 greg 2.38 #if SHADCACHE
405     /* check shadow cache */
406     if (si.np == 1 && srcblocked(&sr)) {
407     cntord[sn].brt = 0.0;
408     continue;
409     }
410     #endif
411 greg 2.7 VCOPY(scp->dir, sr.rdir);
412 greg 2.50 copycolor(sr.rcoef, scp->coef);
413 greg 1.35 /* compute potential */
414 greg 2.51 sr.revf = srcvalue;
415     rayvalue(&sr);
416 greg 2.50 multcolor(sr.rcol, sr.rcoef);
417 greg 2.7 copycolor(scp->val, sr.rcol);
418 greg 2.57 cntord[sn].brt = bright(sr.rcol);
419 greg 1.4 }
420     /* sort contributions */
421 greg 1.45 qsort(cntord, sn, sizeof(CNTPTR), cntcmp);
422 greg 1.13 { /* find last */
423 greg 2.62 int l, m;
424 greg 1.13
425 greg 1.45 ncnts = l = sn;
426     sn = 0;
427 greg 1.13 while ((m = (sn + ncnts) >> 1) != l) {
428     if (cntord[m].brt > 0.0)
429     sn = m;
430     else
431     ncnts = m;
432     l = m;
433     }
434     }
435 greg 2.2 if (ncnts == 0)
436     return; /* no contributions! */
437 greg 1.12 /* accumulate tail */
438     for (sn = ncnts-1; sn > 0; sn--)
439     cntord[sn-1].brt += cntord[sn].brt;
440 greg 1.45 /* compute number to check */
441     nshadcheck = pow((double)ncnts, shadcert) + .5;
442     /* modify threshold */
443 greg 2.63 if (ncnts > MINSHADCNT)
444     ourthresh = shadthresh / r->rweight;
445     else
446     ourthresh = 0;
447 greg 1.10 /* test for shadows */
448 greg 2.13 for (nhits = 0, hwt = 0.0, sn = 0; sn < ncnts;
449     hwt += (double)source[scp->sno].nhits /
450     (double)source[scp->sno].ntests,
451     sn++) {
452 greg 1.10 /* check threshold */
453 greg 1.12 if ((sn+nshadcheck>=ncnts ? cntord[sn].brt :
454 greg 1.27 cntord[sn].brt-cntord[sn+nshadcheck].brt)
455     < ourthresh*bright(r->rcol))
456 greg 1.4 break;
457 greg 2.7 scp = srccnt + cntord[sn].sndx;
458 greg 1.4 /* test for hit */
459 greg 2.52 rayorigin(&sr, SHADOW, r, NULL);
460     copycolor(sr.rcoef, scp->coef);
461 greg 2.7 VCOPY(sr.rdir, scp->dir);
462     sr.rsrc = scp->sno;
463 greg 2.34 /* keep statistics */
464     if (source[scp->sno].ntests++ > 0xfffffff0) {
465     source[scp->sno].ntests >>= 1;
466     source[scp->sno].nhits >>= 1;
467     }
468 greg 1.4 if (localhit(&sr, &thescene) &&
469 greg 2.7 ( sr.ro != source[scp->sno].so ||
470     source[scp->sno].sflags & SFOLLOW )) {
471 greg 1.33 /* follow entire path */
472 greg 2.23 raycont(&sr);
473 greg 1.42 if (trace != NULL)
474     (*trace)(&sr); /* trace execution */
475 greg 2.38 if (bright(sr.rcol) <= FTINY) {
476     #if SHADCACHE
477     if ((scp <= srccnt || scp[-1].sno != scp->sno)
478 greg 2.41 && (scp >= srccnt+ncnts-1 ||
479 greg 2.38 scp[1].sno != scp->sno))
480     srcblocker(&sr);
481     #endif
482 greg 1.4 continue; /* missed! */
483 greg 2.38 }
484 greg 2.55 rayparticipate(&sr);
485 greg 2.51 multcolor(sr.rcol, sr.rcoef);
486 greg 2.7 copycolor(scp->val, sr.rcol);
487 greg 2.51 } else if (trace != NULL &&
488     (source[scp->sno].sflags & (SDISTANT|SVIRTUAL|SFOLLOW))
489     == (SDISTANT|SFOLLOW) &&
490     sourcehit(&sr) && rayshade(&sr, sr.ro->omod)) {
491     (*trace)(&sr); /* trace execution */
492     /* skip call to rayparticipate() & scp->val update */
493 greg 1.4 }
494     /* add contribution if hit */
495 greg 2.7 addcolor(r->rcol, scp->val);
496 greg 1.29 nhits++;
497 greg 2.7 source[scp->sno].nhits++;
498 greg 1.4 }
499 greg 2.13 /* source hit rate */
500     if (hwt > FTINY)
501     hwt = (double)nhits / hwt;
502 greg 1.29 else
503     hwt = 0.5;
504 greg 1.20 #ifdef DEBUG
505 greg 2.13 sprintf(errmsg, "%d tested, %d untested, %f conditional hit rate\n",
506 greg 1.12 sn, ncnts-sn, hwt);
507     eputs(errmsg);
508 greg 1.4 #endif
509     /* add in untested sources */
510 greg 1.12 for ( ; sn < ncnts; sn++) {
511 greg 2.7 scp = srccnt + cntord[sn].sndx;
512     prob = hwt * (double)source[scp->sno].nhits /
513     (double)source[scp->sno].ntests;
514 greg 2.51 if (prob < 1.0)
515     scalecolor(scp->val, prob);
516 greg 2.7 addcolor(r->rcol, scp->val);
517 greg 2.19 }
518     }
519    
520    
521 greg 2.62 void
522 greg 2.38 srcscatter( /* compute source scattering into ray */
523 greg 2.62 RAY *r
524 greg 2.38 )
525 greg 2.19 {
526 greg 2.20 int oldsampndx;
527 greg 2.19 int nsamps;
528     RAY sr;
529     SRCINDEX si;
530 greg 2.25 double t, d;
531     double re, ge, be;
532     COLOR cvext;
533 greg 2.19 int i, j;
534    
535 greg 2.22 if (r->slights == NULL || r->slights[0] == 0
536     || r->gecc >= 1.-FTINY || r->rot >= FHUGE)
537 greg 2.19 return;
538     if (ssampdist <= FTINY || (nsamps = r->rot/ssampdist + .5) < 1)
539     nsamps = 1;
540 greg 2.22 #if MAXSSAMP
541     else if (nsamps > MAXSSAMP)
542     nsamps = MAXSSAMP;
543     #endif
544 greg 2.20 oldsampndx = samplendx;
545     samplendx = random()&0x7fff; /* randomize */
546 greg 2.19 for (i = r->slights[0]; i > 0; i--) { /* for each source */
547 greg 2.25 for (j = 0; j < nsamps; j++) { /* for each sample position */
548 greg 2.19 samplendx++;
549     t = r->rot * (j+frandom())/nsamps;
550 greg 2.25 /* extinction */
551     re = t*colval(r->cext,RED);
552     ge = t*colval(r->cext,GRN);
553     be = t*colval(r->cext,BLU);
554     setcolor(cvext, re > 92. ? 0. : exp(-re),
555     ge > 92. ? 0. : exp(-ge),
556     be > 92. ? 0. : exp(-be));
557     if (intens(cvext) <= FTINY)
558     break; /* too far away */
559 greg 2.19 sr.rorg[0] = r->rorg[0] + r->rdir[0]*t;
560     sr.rorg[1] = r->rorg[1] + r->rdir[1]*t;
561     sr.rorg[2] = r->rorg[2] + r->rdir[2]*t;
562 greg 2.21 initsrcindex(&si); /* sample ray to this source */
563     si.sn = r->slights[i];
564     nopart(&si, &sr);
565     if (!srcray(&sr, NULL, &si) ||
566     sr.rsrc != r->slights[i])
567     continue; /* no path */
568 greg 2.45 #if SHADCACHE
569     if (srcblocked(&sr)) /* check shadow cache */
570     continue;
571     #endif
572 greg 2.19 copycolor(sr.cext, r->cext);
573 greg 2.24 copycolor(sr.albedo, r->albedo);
574 greg 2.19 sr.gecc = r->gecc;
575 gregl 2.26 sr.slights = r->slights;
576 greg 2.19 rayvalue(&sr); /* eval. source ray */
577 greg 2.45 if (bright(sr.rcol) <= FTINY) {
578     #if SHADCACHE
579     srcblocker(&sr); /* add blocker to cache */
580     #endif
581 greg 2.19 continue;
582 greg 2.45 }
583 greg 2.19 if (r->gecc <= FTINY) /* compute P(theta) */
584     d = 1.;
585     else {
586     d = DOT(r->rdir, sr.rdir);
587 greg 2.25 d = 1. + r->gecc*r->gecc - 2.*r->gecc*d;
588     d = (1. - r->gecc*r->gecc) / (d*sqrt(d));
589 greg 2.19 }
590     /* other factors */
591 greg 2.24 d *= si.dom * r->rot / (4.*PI*nsamps);
592 greg 2.19 multcolor(sr.rcol, r->cext);
593 greg 2.24 multcolor(sr.rcol, r->albedo);
594 greg 2.19 scalecolor(sr.rcol, d);
595 greg 2.25 multcolor(sr.rcol, cvext);
596     addcolor(r->rcol, sr.rcol); /* add it in */
597 greg 2.19 }
598 greg 1.1 }
599 greg 2.20 samplendx = oldsampndx;
600 greg 2.4 }
601    
602    
603     /****************************************************************
604     * The following macros were separated from the m_light() routine
605     * because they are very nasty and difficult to understand.
606     */
607    
608 greg 2.11 /* illumblock *
609 greg 2.4 *
610     * We cannot allow an illum to pass to another illum, because that
611     * would almost certainly constitute overcounting.
612     * However, we do allow an illum to pass to another illum
613     * that is actually going to relay to a virtual light source.
614 greg 2.11 * We also prevent an illum from passing to a glow; this provides a
615     * convenient mechanism for defining detailed light source
616     * geometry behind (or inside) an effective radiator.
617 greg 2.4 */
618    
619 greg 2.37 static int
620 greg 2.42 weaksrcmat(OBJECT obj) /* identify material */
621 greg 2.37 {
622 greg 2.47 OBJREC *m = findmaterial(objptr(obj));
623 greg 2.37
624 greg 2.47 if (m == NULL) return(0);
625     return((m->otype==MAT_ILLUM) | (m->otype==MAT_GLOW));
626 greg 2.37 }
627 greg 2.4
628 greg 2.11 #define illumblock(m, r) (!(source[r->rsrc].sflags&SVIRTUAL) && \
629 greg 2.12 r->rod > 0.0 && \
630 greg 2.37 weaksrcmat(source[r->rsrc].so->omod))
631 greg 2.11
632 greg 2.4 /* wrongsource *
633     *
634     * This source is the wrong source (ie. overcounted) if we are
635     * aimed to a different source than the one we hit and the one
636 greg 2.11 * we hit is not an illum that should be passed.
637 greg 2.4 */
638    
639     #define wrongsource(m, r) (r->rsrc>=0 && source[r->rsrc].so!=r->ro && \
640 greg 2.11 (m->otype!=MAT_ILLUM || illumblock(m,r)))
641 greg 2.4
642     /* distglow *
643     *
644     * A distant glow is an object that sometimes acts as a light source,
645     * but is too far away from the test point to be one in this case.
646 greg 2.11 * (Glows with negative radii should NEVER participate in illumination.)
647 greg 2.4 */
648    
649 greg 2.17 #define distglow(m, r, d) (m->otype==MAT_GLOW && \
650 greg 2.10 m->oargs.farg[3] >= -FTINY && \
651 greg 2.17 d > m->oargs.farg[3])
652 greg 2.4
653     /* badcomponent *
654     *
655     * We must avoid counting light sources in the ambient calculation,
656     * since the direct component is handled separately. Therefore, any
657     * ambient ray which hits an active light source must be discarded.
658     * The same is true for stray specular samples, since the specular
659     * contribution from light sources is calculated separately.
660     */
661    
662     #define badcomponent(m, r) (r->crtype&(AMBIENT|SPECULAR) && \
663     !(r->crtype&SHADOW || r->rod < 0.0 || \
664 greg 2.17 /* not 100% correct */ distglow(m, r, r->rot)))
665 greg 2.4
666     /* passillum *
667     *
668     * An illum passes to another material type when we didn't hit it
669     * on purpose (as part of a direct calculation), or it is relaying
670     * a virtual light source.
671     */
672    
673     #define passillum(m, r) (m->otype==MAT_ILLUM && \
674     (r->rsrc<0 || source[r->rsrc].so!=r->ro || \
675     source[r->rsrc].sflags&SVIRTUAL))
676    
677     /* srcignore *
678     *
679 greg 2.10 * The -dv flag is normally on for sources to be visible.
680 greg 2.4 */
681    
682 greg 2.17 #define srcignore(m, r) !(directvis || r->crtype&SHADOW || \
683     distglow(m, r, raydist(r,PRIMARY)))
684 greg 2.4
685    
686 greg 2.62 int
687 greg 2.38 m_light( /* ray hit a light source */
688 greg 2.62 OBJREC *m,
689     RAY *r
690 greg 2.38 )
691 greg 2.4 {
692     /* check for over-counting */
693 greg 2.50 if (badcomponent(m, r)) {
694     setcolor(r->rcoef, 0.0, 0.0, 0.0);
695 greg 2.14 return(1);
696 greg 2.50 }
697     if (wrongsource(m, r)) {
698     setcolor(r->rcoef, 0.0, 0.0, 0.0);
699 greg 2.14 return(1);
700 greg 2.50 }
701 greg 2.4 /* check for passed illum */
702     if (passillum(m, r)) {
703 greg 2.14 if (m->oargs.nsargs && strcmp(m->oargs.sarg[0], VOIDID))
704 gwlarson 2.28 return(rayshade(r,lastmod(objndx(m),m->oargs.sarg[0])));
705 greg 2.14 raytrans(r);
706     return(1);
707 greg 2.4 }
708 greg 2.50 /* check for invisibility */
709     if (srcignore(m, r)) {
710     setcolor(r->rcoef, 0.0, 0.0, 0.0);
711     return(1);
712     }
713 greg 2.4 /* otherwise treat as source */
714     /* check for behind */
715     if (r->rod < 0.0)
716 greg 2.14 return(1);
717 greg 2.4 /* check for outside spot */
718 greg 2.18 if (m->otype==MAT_SPOT && spotout(r, makespot(m)))
719 greg 2.14 return(1);
720 greg 2.4 /* get distribution pattern */
721     raytexture(r, m->omod);
722     /* get source color */
723     setcolor(r->rcol, m->oargs.farg[0],
724     m->oargs.farg[1],
725     m->oargs.farg[2]);
726     /* modify value */
727     multcolor(r->rcol, r->pcol);
728 greg 2.14 return(1);
729 greg 1.1 }