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 |
|
*/ |
170 |
|
return; |
171 |
|
if (!rayshade(r, r->ro->omod)) /* compute contribution */ |
172 |
|
goto nomat; |
173 |
+ |
rayparticipate(r); |
174 |
|
return; |
175 |
|
} |
176 |
|
/* compute intersection */ |
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! */ |
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) |
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 |
+ |
for (i = r->slights[0]; i > 0; i--) { /* for each source */ |
392 |
+ |
setcolor(cumval, 0., 0., 0.); |
393 |
+ |
lastt = r->rot; |
394 |
+ |
for (j = nsamps; j-- > 0; ) { /* for each sample position */ |
395 |
+ |
samplendx++; |
396 |
+ |
t = r->rot * (j+frandom())/nsamps; |
397 |
+ |
sr.rorg[0] = r->rorg[0] + r->rdir[0]*t; |
398 |
+ |
sr.rorg[1] = r->rorg[1] + r->rdir[1]*t; |
399 |
+ |
sr.rorg[2] = r->rorg[2] + r->rdir[2]*t; |
400 |
+ |
sr.rmax = 0.; |
401 |
+ |
initsrcindex(&si); /* sample ray to this source */ |
402 |
+ |
si.sn = r->slights[i]; |
403 |
+ |
nopart(&si, &sr); |
404 |
+ |
if (!srcray(&sr, NULL, &si) || |
405 |
+ |
sr.rsrc != r->slights[i]) |
406 |
+ |
continue; /* no path */ |
407 |
+ |
copycolor(sr.cext, r->cext); |
408 |
+ |
sr.albedo = r->albedo; |
409 |
+ |
sr.gecc = r->gecc; |
410 |
+ |
rayvalue(&sr); /* eval. source ray */ |
411 |
+ |
if (bright(sr.rcol) <= FTINY) |
412 |
+ |
continue; |
413 |
+ |
/* compute fall-off */ |
414 |
+ |
d = lastt - t; |
415 |
+ |
setcolor(ctmp, 1.-d*colval(r->cext,RED), |
416 |
+ |
1.-d*colval(r->cext,GRN), |
417 |
+ |
1.-d*colval(r->cext,BLU)); |
418 |
+ |
multcolor(cumval, ctmp); |
419 |
+ |
lastt = t; |
420 |
+ |
if (r->gecc <= FTINY) /* compute P(theta) */ |
421 |
+ |
d = 1.; |
422 |
+ |
else { |
423 |
+ |
d = DOT(r->rdir, sr.rdir); |
424 |
+ |
d = sqrt(1. + r->gecc*r->gecc - 2.*r->gecc*d); |
425 |
+ |
d = (1. - r->gecc*r->gecc) / (d*d*d); |
426 |
+ |
} |
427 |
+ |
/* other factors */ |
428 |
+ |
d *= si.dom * r->albedo * r->rot / (4.*PI*nsamps); |
429 |
+ |
multcolor(sr.rcol, r->cext); |
430 |
+ |
scalecolor(sr.rcol, d); |
431 |
+ |
addcolor(cumval, sr.rcol); |
432 |
+ |
} |
433 |
+ |
/* final fall-off */ |
434 |
+ |
setcolor(ctmp, 1.-lastt*colval(r->cext,RED), |
435 |
+ |
1.-lastt*colval(r->cext,GRN), |
436 |
+ |
1.-lastt*colval(r->cext,BLU)); |
437 |
+ |
multcolor(cumval, ctmp); |
438 |
+ |
addcolor(r->rcol, cumval); /* sum into ray result */ |
439 |
+ |
} |
440 |
+ |
samplendx = oldsampndx; |
441 |
|
} |
442 |
|
|
443 |
|
|