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root/radiance/ray/src/rt/source.c
Revision: 2.61
Committed: Tue Aug 2 22:47:30 2011 UTC (12 years, 9 months ago) by greg
Content type: text/plain
Branch: MAIN
CVS Tags: rad4R1
Changes since 2.60: +11 -9 lines
Log Message:
Eliminated warning for "no light sources found" under normal circumstances

File Contents

# User Rev Content
1 greg 1.1 #ifndef lint
2 greg 2.61 static const char RCSid[] = "$Id: source.c,v 2.60 2011/02/14 20:13:38 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     extern double ssampdist; /* scatter sampling distance */
17    
18 greg 2.22 #ifndef MAXSSAMP
19     #define MAXSSAMP 16 /* maximum samples per ray */
20     #endif
21    
22 greg 1.35 /*
23     * Structures used by direct()
24     */
25 greg 1.1
26 greg 1.35 typedef struct {
27 greg 1.45 int sno; /* source number */
28 greg 1.35 FVECT dir; /* source direction */
29     COLOR coef; /* material coefficient */
30     COLOR val; /* contribution */
31     } CONTRIB; /* direct contribution */
32 greg 1.1
33 greg 1.35 typedef struct {
34 greg 1.45 int sndx; /* source index (to CONTRIB array) */
35 greg 1.35 float brt; /* brightness (for comparison) */
36     } CNTPTR; /* contribution pointer */
37 greg 1.1
38 greg 1.25 static CONTRIB *srccnt; /* source contributions in direct() */
39     static CNTPTR *cntord; /* source ordering in direct() */
40 greg 1.45 static int maxcntr = 0; /* size of contribution arrays */
41 greg 1.1
42 schorsch 2.44 static int cntcmp(const void *p1, const void *p2);
43    
44 greg 1.25
45 schorsch 2.44 extern OBJREC * /* find an object's actual material */
46 greg 2.38 findmaterial(register OBJREC *o)
47     {
48     while (!ismaterial(o->otype)) {
49     if (o->otype == MOD_ALIAS && o->oargs.nsargs) {
50     OBJECT aobj;
51     OBJREC *ao;
52     aobj = lastmod(objndx(o), o->oargs.sarg[0]);
53     if (aobj < 0)
54     objerror(o, USER, "bad reference");
55     ao = objptr(aobj);
56     if (ismaterial(ao->otype))
57     return(ao);
58 greg 2.54 if (ao->otype == MOD_ALIAS) {
59     o = ao;
60     continue;
61     }
62 greg 2.38 }
63     if (o->omod == OVOID)
64     return(NULL);
65     o = objptr(o->omod);
66     }
67 greg 2.48 return(o); /* mixtures will return NULL */
68 greg 2.38 }
69    
70    
71 schorsch 2.44 extern void
72     marksources(void) /* find and mark source objects */
73 greg 1.1 {
74 greg 2.3 int foundsource = 0;
75 greg 1.33 int i;
76 greg 1.1 register OBJREC *o, *m;
77 greg 1.36 register int ns;
78 greg 1.35 /* initialize dispatch table */
79     initstypes();
80     /* find direct sources */
81 greg 2.33 for (i = 0; i < nsceneobjs; i++) {
82 greg 1.1
83     o = objptr(i);
84    
85 greg 1.35 if (!issurface(o->otype) || o->omod == OVOID)
86 greg 1.1 continue;
87 greg 2.36 /* find material */
88 greg 2.43 m = findmaterial(objptr(o->omod));
89 greg 2.56 if (m == NULL)
90     continue;
91     if (m->otype == MAT_CLIP) {
92     markclip(m); /* special case for antimatter */
93     continue;
94     }
95     if (!islight(m->otype))
96 greg 2.36 continue; /* not source modifier */
97 greg 1.1
98 greg 1.6 if (m->oargs.nfargs != (m->otype == MAT_GLOW ? 4 :
99     m->otype == MAT_SPOT ? 7 : 3))
100 greg 1.1 objerror(m, USER, "bad # arguments");
101    
102 greg 2.16 if (m->oargs.farg[0] <= FTINY && m->oargs.farg[1] <= FTINY &&
103     m->oargs.farg[2] <= FTINY)
104     continue; /* don't bother */
105 greg 2.61 if (m->otype == MAT_GLOW &&
106     o->otype != OBJ_SOURCE &&
107     m->oargs.farg[3] <= FTINY) {
108     foundsource += (ambounce > 0);
109     continue; /* don't track these */
110     }
111 greg 1.35 if (sfun[o->otype].of == NULL ||
112     sfun[o->otype].of->setsrc == NULL)
113     objerror(o, USER, "illegal material");
114    
115 greg 1.36 if ((ns = newsource()) < 0)
116 greg 1.25 goto memerr;
117 greg 1.1
118 greg 1.37 setsource(&source[ns], o);
119 greg 1.1
120 greg 1.6 if (m->otype == MAT_GLOW) {
121 greg 1.36 source[ns].sflags |= SPROX;
122     source[ns].sl.prox = m->oargs.farg[3];
123 greg 2.61 if (source[ns].sflags & SDISTANT) {
124 greg 1.36 source[ns].sflags |= SSKIP;
125 greg 2.61 foundsource += (ambounce > 0);
126     }
127 greg 1.6 } else if (m->otype == MAT_SPOT) {
128 greg 1.36 source[ns].sflags |= SSPOT;
129     if ((source[ns].sl.s = makespot(m)) == NULL)
130 greg 1.33 goto memerr;
131 greg 1.38 if (source[ns].sflags & SFLAT &&
132     !checkspot(source[ns].sl.s,source[ns].snorm)) {
133     objerror(o, WARNING,
134     "invalid spotlight direction");
135     source[ns].sflags |= SSKIP;
136     }
137 greg 1.6 }
138 greg 2.38 #if SHADCACHE
139 greg 2.46 initobscache(ns);
140 greg 2.38 #endif
141 greg 2.61 foundsource += !(source[ns].sflags & SSKIP);
142 greg 1.1 }
143 greg 2.3 if (!foundsource) {
144 greg 1.25 error(WARNING, "no light sources found");
145     return;
146     }
147 greg 1.33 markvirtuals(); /* find and add virtual sources */
148 greg 1.45 /* allocate our contribution arrays */
149 greg 1.48 maxcntr = nsources + MAXSPART; /* start with this many */
150 greg 1.45 srccnt = (CONTRIB *)malloc(maxcntr*sizeof(CONTRIB));
151     cntord = (CNTPTR *)malloc(maxcntr*sizeof(CNTPTR));
152 schorsch 2.35 if ((srccnt == NULL) | (cntord == NULL))
153 greg 1.33 goto memerr;
154     return;
155 greg 1.25 memerr:
156     error(SYSTEM, "out of memory in marksources");
157 greg 1.1 }
158    
159    
160 schorsch 2.44 extern void
161     freesources(void) /* free all source structures */
162 greg 2.29 {
163     if (nsources > 0) {
164 greg 2.38 #if SHADCACHE
165     while (nsources--)
166     freeobscache(&source[nsources]);
167     #endif
168 greg 2.29 free((void *)source);
169     source = NULL;
170     nsources = 0;
171     }
172 greg 2.60 markclip(NULL);
173 greg 2.29 if (maxcntr <= 0)
174     return;
175     free((void *)srccnt);
176     srccnt = NULL;
177     free((void *)cntord);
178     cntord = NULL;
179     maxcntr = 0;
180     }
181    
182    
183 schorsch 2.44 extern int
184 greg 2.38 srcray( /* send a ray to a source, return domega */
185 schorsch 2.44 register RAY *sr, /* returned source ray */
186     RAY *r, /* ray which hit object */
187     SRCINDEX *si /* source sample index */
188 greg 2.38 )
189 greg 1.1 {
190 greg 2.59 double d; /* distance to source */
191     register SRCREC *srcp;
192 greg 1.1
193 greg 2.59 rayorigin(sr, SHADOW, r, NULL); /* ignore limits */
194 greg 1.1
195 greg 2.59 if (r == NULL)
196     sr->rmax = 0.0;
197    
198     while ((d = nextssamp(sr, si)) != 0.0) {
199     sr->rsrc = si->sn; /* remember source */
200     srcp = source + si->sn;
201     if (srcp->sflags & SDISTANT) {
202     if (srcp->sflags & SSPOT && spotout(sr, srcp->sl.s))
203     continue;
204     return(1); /* sample OK */
205     }
206 greg 1.45 /* local source */
207 greg 1.6 /* check proximity */
208 greg 2.59 if (srcp->sflags & SPROX && d > srcp->sl.prox)
209     continue;
210 greg 1.6 /* check angle */
211 greg 2.59 if (srcp->sflags & SSPOT) {
212     if (spotout(sr, srcp->sl.s))
213     continue;
214 greg 1.45 /* adjust solid angle */
215 greg 2.59 si->dom *= d*d;
216     d += srcp->sl.s->flen;
217     si->dom /= d*d;
218     }
219     return(1); /* sample OK */
220     }
221     return(0); /* no more samples */
222 greg 1.1 }
223    
224    
225 schorsch 2.44 extern void
226 greg 2.38 srcvalue( /* punch ray to source and compute value */
227 schorsch 2.44 register RAY *r
228 greg 2.38 )
229 greg 1.1 {
230 greg 1.35 register SRCREC *sp;
231 greg 1.1
232 greg 1.35 sp = &source[r->rsrc];
233     if (sp->sflags & SVIRTUAL) { /* virtual source */
234     /* check intersection */
235     if (!(*ofun[sp->so->otype].funp)(sp->so, r))
236     return;
237 greg 2.15 if (!rayshade(r, r->ro->omod)) /* compute contribution */
238     goto nomat;
239 greg 2.19 rayparticipate(r);
240 greg 1.35 return;
241 greg 1.1 }
242 greg 1.35 /* compute intersection */
243     if (sp->sflags & SDISTANT ? sourcehit(r) :
244     (*ofun[sp->so->otype].funp)(sp->so, r)) {
245     if (sp->sa.success >= 0)
246     sp->sa.success++;
247 greg 2.15 if (!rayshade(r, r->ro->omod)) /* compute contribution */
248     goto nomat;
249 greg 2.19 rayparticipate(r);
250 greg 1.35 return;
251 greg 1.1 }
252 greg 2.15 /* we missed our mark! */
253 greg 1.35 if (sp->sa.success < 0)
254     return; /* bitched already */
255     sp->sa.success -= AIMREQT;
256     if (sp->sa.success >= 0)
257     return; /* leniency */
258     sprintf(errmsg, "aiming failure for light source \"%s\"",
259     sp->so->oname);
260     error(WARNING, errmsg); /* issue warning */
261 greg 2.15 return;
262     nomat:
263     objerror(r->ro, USER, "material not found");
264 greg 1.1 }
265    
266    
267 greg 2.47 static int
268     transillum( /* check if material is transparent illum */
269     OBJECT obj
270     )
271     {
272     OBJREC *m = findmaterial(objptr(obj));
273    
274     if (m == NULL)
275     return(1);
276     if (m->otype != MAT_ILLUM)
277     return(0);
278     return(!m->oargs.nsargs || !strcmp(m->oargs.sarg[0], VOIDID));
279     }
280    
281    
282 schorsch 2.44 extern int
283 greg 2.38 sourcehit( /* check to see if ray hit distant source */
284 schorsch 2.44 register RAY *r
285 greg 2.38 )
286 greg 2.5 {
287 greg 2.47 int glowsrc = -1;
288     int transrc = -1;
289 greg 2.5 int first, last;
290     register int i;
291    
292     if (r->rsrc >= 0) { /* check only one if aimed */
293     first = last = r->rsrc;
294     } else { /* otherwise check all */
295     first = 0; last = nsources-1;
296     }
297 greg 2.47 for (i = first; i <= last; i++) {
298     if ((source[i].sflags & (SDISTANT|SVIRTUAL)) != SDISTANT)
299     continue;
300     /*
301     * Check to see if ray is within
302     * solid angle of source.
303     */
304     if (2.*PI*(1. - DOT(source[i].sloc,r->rdir)) > source[i].ss2)
305     continue;
306     /* is it the only possibility? */
307     if (first == last) {
308     r->ro = source[i].so;
309     break;
310     }
311     /*
312     * If it's a glow or transparent illum, just remember it.
313     */
314     if (source[i].sflags & SSKIP) {
315 greg 2.58 if (glowsrc < 0)
316     glowsrc = i;
317 greg 2.47 continue;
318     }
319     if (transillum(source[i].so->omod)) {
320 greg 2.58 if (transrc < 0)
321     transrc = i;
322 greg 2.47 continue;
323     }
324     r->ro = source[i].so; /* otherwise, use first hit */
325     break;
326 greg 2.5 }
327 greg 2.47 /*
328     * Do we need fallback?
329     */
330     if (r->ro == NULL) {
331     if (transrc >= 0 && r->crtype & (AMBIENT|SPECULAR))
332     return(0); /* avoid overcounting */
333     if (glowsrc >= 0)
334     r->ro = source[glowsrc].so;
335     else
336     return(0); /* nothing usable */
337     }
338     /*
339     * Make assignments.
340     */
341     r->robj = objndx(r->ro);
342     for (i = 0; i < 3; i++)
343     r->ron[i] = -r->rdir[i];
344     r->rod = 1.0;
345     r->pert[0] = r->pert[1] = r->pert[2] = 0.0;
346     r->uv[0] = r->uv[1] = 0.0;
347     r->rox = NULL;
348     return(1);
349 greg 2.5 }
350 greg 2.38
351    
352 greg 1.4 static int
353 greg 2.38 cntcmp( /* contribution compare (descending) */
354 schorsch 2.44 const void *p1,
355     const void *p2
356 greg 2.38 )
357 greg 1.4 {
358 greg 2.38 register const CNTPTR *sc1 = (const CNTPTR *)p1;
359     register const CNTPTR *sc2 = (const CNTPTR *)p2;
360    
361 greg 1.4 if (sc1->brt > sc2->brt)
362     return(-1);
363     if (sc1->brt < sc2->brt)
364     return(1);
365     return(0);
366     }
367    
368    
369 schorsch 2.44 extern void
370 greg 2.38 direct( /* add direct component */
371 schorsch 2.44 RAY *r, /* ray that hit surface */
372     srcdirf_t *f, /* direct component coefficient function */
373     void *p /* data for f */
374 greg 2.38 )
375 greg 1.4 {
376     register int sn;
377 greg 2.7 register CONTRIB *scp;
378 greg 1.45 SRCINDEX si;
379 greg 1.12 int nshadcheck, ncnts;
380 greg 1.29 int nhits;
381 greg 1.45 double prob, ourthresh, hwt;
382 greg 1.4 RAY sr;
383 greg 1.25 /* NOTE: srccnt and cntord global so no recursion */
384 greg 1.22 if (nsources <= 0)
385 greg 1.25 return; /* no sources?! */
386 greg 1.4 /* potential contributions */
387 greg 1.45 initsrcindex(&si);
388     for (sn = 0; srcray(&sr, r, &si); sn++) {
389     if (sn >= maxcntr) {
390     maxcntr = sn + MAXSPART;
391 greg 2.32 srccnt = (CONTRIB *)realloc((void *)srccnt,
392 greg 1.45 maxcntr*sizeof(CONTRIB));
393 greg 2.32 cntord = (CNTPTR *)realloc((void *)cntord,
394 greg 1.45 maxcntr*sizeof(CNTPTR));
395 schorsch 2.35 if ((srccnt == NULL) | (cntord == NULL))
396 greg 1.45 error(SYSTEM, "out of memory in direct");
397     }
398     cntord[sn].sndx = sn;
399 greg 2.7 scp = srccnt + sn;
400     scp->sno = sr.rsrc;
401 greg 1.4 /* compute coefficient */
402 greg 2.7 (*f)(scp->coef, p, sr.rdir, si.dom);
403 greg 2.53 cntord[sn].brt = intens(scp->coef);
404 greg 1.15 if (cntord[sn].brt <= 0.0)
405 greg 1.4 continue;
406 greg 2.38 #if SHADCACHE
407     /* check shadow cache */
408     if (si.np == 1 && srcblocked(&sr)) {
409     cntord[sn].brt = 0.0;
410     continue;
411     }
412     #endif
413 greg 2.7 VCOPY(scp->dir, sr.rdir);
414 greg 2.50 copycolor(sr.rcoef, scp->coef);
415 greg 1.35 /* compute potential */
416 greg 2.51 sr.revf = srcvalue;
417     rayvalue(&sr);
418 greg 2.50 multcolor(sr.rcol, sr.rcoef);
419 greg 2.7 copycolor(scp->val, sr.rcol);
420 greg 2.57 cntord[sn].brt = bright(sr.rcol);
421 greg 1.4 }
422     /* sort contributions */
423 greg 1.45 qsort(cntord, sn, sizeof(CNTPTR), cntcmp);
424 greg 1.13 { /* find last */
425     register int l, m;
426    
427 greg 1.45 ncnts = l = sn;
428     sn = 0;
429 greg 1.13 while ((m = (sn + ncnts) >> 1) != l) {
430     if (cntord[m].brt > 0.0)
431     sn = m;
432     else
433     ncnts = m;
434     l = m;
435     }
436     }
437 greg 2.2 if (ncnts == 0)
438     return; /* no contributions! */
439 greg 1.12 /* accumulate tail */
440     for (sn = ncnts-1; sn > 0; sn--)
441     cntord[sn-1].brt += cntord[sn].brt;
442 greg 1.45 /* compute number to check */
443     nshadcheck = pow((double)ncnts, shadcert) + .5;
444     /* modify threshold */
445     ourthresh = shadthresh / r->rweight;
446 greg 1.10 /* test for shadows */
447 greg 2.13 for (nhits = 0, hwt = 0.0, sn = 0; sn < ncnts;
448     hwt += (double)source[scp->sno].nhits /
449     (double)source[scp->sno].ntests,
450     sn++) {
451 greg 1.10 /* check threshold */
452 greg 1.12 if ((sn+nshadcheck>=ncnts ? cntord[sn].brt :
453 greg 1.27 cntord[sn].brt-cntord[sn+nshadcheck].brt)
454     < ourthresh*bright(r->rcol))
455 greg 1.4 break;
456 greg 2.7 scp = srccnt + cntord[sn].sndx;
457 greg 1.4 /* test for hit */
458 greg 2.52 rayorigin(&sr, SHADOW, r, NULL);
459     copycolor(sr.rcoef, scp->coef);
460 greg 2.7 VCOPY(sr.rdir, scp->dir);
461     sr.rsrc = scp->sno;
462 greg 2.34 /* keep statistics */
463     if (source[scp->sno].ntests++ > 0xfffffff0) {
464     source[scp->sno].ntests >>= 1;
465     source[scp->sno].nhits >>= 1;
466     }
467 greg 1.4 if (localhit(&sr, &thescene) &&
468 greg 2.7 ( sr.ro != source[scp->sno].so ||
469     source[scp->sno].sflags & SFOLLOW )) {
470 greg 1.33 /* follow entire path */
471 greg 2.23 raycont(&sr);
472 greg 1.42 if (trace != NULL)
473     (*trace)(&sr); /* trace execution */
474 greg 2.38 if (bright(sr.rcol) <= FTINY) {
475     #if SHADCACHE
476     if ((scp <= srccnt || scp[-1].sno != scp->sno)
477 greg 2.41 && (scp >= srccnt+ncnts-1 ||
478 greg 2.38 scp[1].sno != scp->sno))
479     srcblocker(&sr);
480     #endif
481 greg 1.4 continue; /* missed! */
482 greg 2.38 }
483 greg 2.55 rayparticipate(&sr);
484 greg 2.51 multcolor(sr.rcol, sr.rcoef);
485 greg 2.7 copycolor(scp->val, sr.rcol);
486 greg 2.51 } else if (trace != NULL &&
487     (source[scp->sno].sflags & (SDISTANT|SVIRTUAL|SFOLLOW))
488     == (SDISTANT|SFOLLOW) &&
489     sourcehit(&sr) && rayshade(&sr, sr.ro->omod)) {
490     (*trace)(&sr); /* trace execution */
491     /* skip call to rayparticipate() & scp->val update */
492 greg 1.4 }
493     /* add contribution if hit */
494 greg 2.7 addcolor(r->rcol, scp->val);
495 greg 1.29 nhits++;
496 greg 2.7 source[scp->sno].nhits++;
497 greg 1.4 }
498 greg 2.13 /* source hit rate */
499     if (hwt > FTINY)
500     hwt = (double)nhits / hwt;
501 greg 1.29 else
502     hwt = 0.5;
503 greg 1.20 #ifdef DEBUG
504 greg 2.13 sprintf(errmsg, "%d tested, %d untested, %f conditional hit rate\n",
505 greg 1.12 sn, ncnts-sn, hwt);
506     eputs(errmsg);
507 greg 1.4 #endif
508     /* add in untested sources */
509 greg 1.12 for ( ; sn < ncnts; sn++) {
510 greg 2.7 scp = srccnt + cntord[sn].sndx;
511     prob = hwt * (double)source[scp->sno].nhits /
512     (double)source[scp->sno].ntests;
513 greg 2.51 if (prob < 1.0)
514     scalecolor(scp->val, prob);
515 greg 2.7 addcolor(r->rcol, scp->val);
516 greg 2.19 }
517     }
518    
519    
520 schorsch 2.44 extern void
521 greg 2.38 srcscatter( /* compute source scattering into ray */
522 schorsch 2.44 register RAY *r
523 greg 2.38 )
524 greg 2.19 {
525 greg 2.20 int oldsampndx;
526 greg 2.19 int nsamps;
527     RAY sr;
528     SRCINDEX si;
529 greg 2.25 double t, d;
530     double re, ge, be;
531     COLOR cvext;
532 greg 2.19 int i, j;
533    
534 greg 2.22 if (r->slights == NULL || r->slights[0] == 0
535     || r->gecc >= 1.-FTINY || r->rot >= FHUGE)
536 greg 2.19 return;
537     if (ssampdist <= FTINY || (nsamps = r->rot/ssampdist + .5) < 1)
538     nsamps = 1;
539 greg 2.22 #if MAXSSAMP
540     else if (nsamps > MAXSSAMP)
541     nsamps = MAXSSAMP;
542     #endif
543 greg 2.20 oldsampndx = samplendx;
544     samplendx = random()&0x7fff; /* randomize */
545 greg 2.19 for (i = r->slights[0]; i > 0; i--) { /* for each source */
546 greg 2.25 for (j = 0; j < nsamps; j++) { /* for each sample position */
547 greg 2.19 samplendx++;
548     t = r->rot * (j+frandom())/nsamps;
549 greg 2.25 /* extinction */
550     re = t*colval(r->cext,RED);
551     ge = t*colval(r->cext,GRN);
552     be = t*colval(r->cext,BLU);
553     setcolor(cvext, re > 92. ? 0. : exp(-re),
554     ge > 92. ? 0. : exp(-ge),
555     be > 92. ? 0. : exp(-be));
556     if (intens(cvext) <= FTINY)
557     break; /* too far away */
558 greg 2.19 sr.rorg[0] = r->rorg[0] + r->rdir[0]*t;
559     sr.rorg[1] = r->rorg[1] + r->rdir[1]*t;
560     sr.rorg[2] = r->rorg[2] + r->rdir[2]*t;
561 greg 2.21 initsrcindex(&si); /* sample ray to this source */
562     si.sn = r->slights[i];
563     nopart(&si, &sr);
564     if (!srcray(&sr, NULL, &si) ||
565     sr.rsrc != r->slights[i])
566     continue; /* no path */
567 greg 2.45 #if SHADCACHE
568     if (srcblocked(&sr)) /* check shadow cache */
569     continue;
570     #endif
571 greg 2.19 copycolor(sr.cext, r->cext);
572 greg 2.24 copycolor(sr.albedo, r->albedo);
573 greg 2.19 sr.gecc = r->gecc;
574 gregl 2.26 sr.slights = r->slights;
575 greg 2.19 rayvalue(&sr); /* eval. source ray */
576 greg 2.45 if (bright(sr.rcol) <= FTINY) {
577     #if SHADCACHE
578     srcblocker(&sr); /* add blocker to cache */
579     #endif
580 greg 2.19 continue;
581 greg 2.45 }
582 greg 2.19 if (r->gecc <= FTINY) /* compute P(theta) */
583     d = 1.;
584     else {
585     d = DOT(r->rdir, sr.rdir);
586 greg 2.25 d = 1. + r->gecc*r->gecc - 2.*r->gecc*d;
587     d = (1. - r->gecc*r->gecc) / (d*sqrt(d));
588 greg 2.19 }
589     /* other factors */
590 greg 2.24 d *= si.dom * r->rot / (4.*PI*nsamps);
591 greg 2.19 multcolor(sr.rcol, r->cext);
592 greg 2.24 multcolor(sr.rcol, r->albedo);
593 greg 2.19 scalecolor(sr.rcol, d);
594 greg 2.25 multcolor(sr.rcol, cvext);
595     addcolor(r->rcol, sr.rcol); /* add it in */
596 greg 2.19 }
597 greg 1.1 }
598 greg 2.20 samplendx = oldsampndx;
599 greg 2.4 }
600    
601    
602     /****************************************************************
603     * The following macros were separated from the m_light() routine
604     * because they are very nasty and difficult to understand.
605     */
606    
607 greg 2.11 /* illumblock *
608 greg 2.4 *
609     * We cannot allow an illum to pass to another illum, because that
610     * would almost certainly constitute overcounting.
611     * However, we do allow an illum to pass to another illum
612     * that is actually going to relay to a virtual light source.
613 greg 2.11 * We also prevent an illum from passing to a glow; this provides a
614     * convenient mechanism for defining detailed light source
615     * geometry behind (or inside) an effective radiator.
616 greg 2.4 */
617    
618 greg 2.37 static int
619 greg 2.42 weaksrcmat(OBJECT obj) /* identify material */
620 greg 2.37 {
621 greg 2.47 OBJREC *m = findmaterial(objptr(obj));
622 greg 2.37
623 greg 2.47 if (m == NULL) return(0);
624     return((m->otype==MAT_ILLUM) | (m->otype==MAT_GLOW));
625 greg 2.37 }
626 greg 2.4
627 greg 2.11 #define illumblock(m, r) (!(source[r->rsrc].sflags&SVIRTUAL) && \
628 greg 2.12 r->rod > 0.0 && \
629 greg 2.37 weaksrcmat(source[r->rsrc].so->omod))
630 greg 2.11
631 greg 2.4 /* wrongsource *
632     *
633     * This source is the wrong source (ie. overcounted) if we are
634     * aimed to a different source than the one we hit and the one
635 greg 2.11 * we hit is not an illum that should be passed.
636 greg 2.4 */
637    
638     #define wrongsource(m, r) (r->rsrc>=0 && source[r->rsrc].so!=r->ro && \
639 greg 2.11 (m->otype!=MAT_ILLUM || illumblock(m,r)))
640 greg 2.4
641     /* distglow *
642     *
643     * A distant glow is an object that sometimes acts as a light source,
644     * but is too far away from the test point to be one in this case.
645 greg 2.11 * (Glows with negative radii should NEVER participate in illumination.)
646 greg 2.4 */
647    
648 greg 2.17 #define distglow(m, r, d) (m->otype==MAT_GLOW && \
649 greg 2.10 m->oargs.farg[3] >= -FTINY && \
650 greg 2.17 d > m->oargs.farg[3])
651 greg 2.4
652     /* badcomponent *
653     *
654     * We must avoid counting light sources in the ambient calculation,
655     * since the direct component is handled separately. Therefore, any
656     * ambient ray which hits an active light source must be discarded.
657     * The same is true for stray specular samples, since the specular
658     * contribution from light sources is calculated separately.
659     */
660    
661     #define badcomponent(m, r) (r->crtype&(AMBIENT|SPECULAR) && \
662     !(r->crtype&SHADOW || r->rod < 0.0 || \
663 greg 2.17 /* not 100% correct */ distglow(m, r, r->rot)))
664 greg 2.4
665     /* passillum *
666     *
667     * An illum passes to another material type when we didn't hit it
668     * on purpose (as part of a direct calculation), or it is relaying
669     * a virtual light source.
670     */
671    
672     #define passillum(m, r) (m->otype==MAT_ILLUM && \
673     (r->rsrc<0 || source[r->rsrc].so!=r->ro || \
674     source[r->rsrc].sflags&SVIRTUAL))
675    
676     /* srcignore *
677     *
678 greg 2.10 * The -dv flag is normally on for sources to be visible.
679 greg 2.4 */
680    
681 greg 2.17 #define srcignore(m, r) !(directvis || r->crtype&SHADOW || \
682     distglow(m, r, raydist(r,PRIMARY)))
683 greg 2.4
684    
685 schorsch 2.44 extern int
686 greg 2.38 m_light( /* ray hit a light source */
687 schorsch 2.44 register OBJREC *m,
688     register RAY *r
689 greg 2.38 )
690 greg 2.4 {
691     /* check for over-counting */
692 greg 2.50 if (badcomponent(m, r)) {
693     setcolor(r->rcoef, 0.0, 0.0, 0.0);
694 greg 2.14 return(1);
695 greg 2.50 }
696     if (wrongsource(m, r)) {
697     setcolor(r->rcoef, 0.0, 0.0, 0.0);
698 greg 2.14 return(1);
699 greg 2.50 }
700 greg 2.4 /* check for passed illum */
701     if (passillum(m, r)) {
702 greg 2.14 if (m->oargs.nsargs && strcmp(m->oargs.sarg[0], VOIDID))
703 gwlarson 2.28 return(rayshade(r,lastmod(objndx(m),m->oargs.sarg[0])));
704 greg 2.14 raytrans(r);
705     return(1);
706 greg 2.4 }
707 greg 2.50 /* check for invisibility */
708     if (srcignore(m, r)) {
709     setcolor(r->rcoef, 0.0, 0.0, 0.0);
710     return(1);
711     }
712 greg 2.4 /* otherwise treat as source */
713     /* check for behind */
714     if (r->rod < 0.0)
715 greg 2.14 return(1);
716 greg 2.4 /* check for outside spot */
717 greg 2.18 if (m->otype==MAT_SPOT && spotout(r, makespot(m)))
718 greg 2.14 return(1);
719 greg 2.4 /* get distribution pattern */
720     raytexture(r, m->omod);
721     /* get source color */
722     setcolor(r->rcol, m->oargs.farg[0],
723     m->oargs.farg[1],
724     m->oargs.farg[2]);
725     /* modify value */
726     multcolor(r->rcol, r->pcol);
727 greg 2.14 return(1);
728 greg 1.1 }