| 24 |
|
extern int maxdepth; /* maximum recursion depth */ |
| 25 |
|
extern double minweight; /* minimum ray weight */ |
| 26 |
|
extern int do_irrad; /* compute irradiance? */ |
| 27 |
+ |
extern COLOR ambval; /* ambient value */ |
| 28 |
|
|
| 29 |
+ |
extern COLOR cextinction; /* global extinction coefficient */ |
| 30 |
+ |
extern double salbedo; /* global scattering albedo */ |
| 31 |
+ |
extern double seccg; /* global scattering eccentricity */ |
| 32 |
+ |
extern double ssampdist; /* scatter sampling distance */ |
| 33 |
+ |
|
| 34 |
|
unsigned long raynum = 0; /* next unique ray number */ |
| 35 |
|
unsigned long nrays = 0; /* number of calls to localhit */ |
| 36 |
|
|
| 61 |
|
r->rsrc = -1; |
| 62 |
|
r->clipset = NULL; |
| 63 |
|
r->revf = raytrace; |
| 64 |
+ |
copycolor(r->cext, cextinction); |
| 65 |
+ |
r->albedo = salbedo; |
| 66 |
+ |
r->gecc = seccg; |
| 67 |
+ |
r->slights = NULL; |
| 68 |
|
} else { /* spawned ray */ |
| 69 |
|
r->rlvl = ro->rlvl; |
| 70 |
|
if (rt & RAYREFL) { |
| 78 |
|
r->rmax = ro->rmax <= FTINY ? 0.0 : ro->rmax - ro->rot; |
| 79 |
|
} |
| 80 |
|
r->revf = ro->revf; |
| 81 |
+ |
copycolor(r->cext, ro->cext); |
| 82 |
+ |
r->albedo = ro->albedo; |
| 83 |
+ |
r->gecc = ro->gecc; |
| 84 |
+ |
r->slights = ro->slights; |
| 85 |
|
r->rweight = ro->rweight * rw; |
| 86 |
|
r->crtype = ro->crtype | (r->rtype = rt); |
| 87 |
|
VCOPY(r->rorg, ro->rop); |
| 112 |
|
int gotmat; |
| 113 |
|
|
| 114 |
|
if (localhit(r, &thescene)) |
| 115 |
< |
gotmat = raycont(r); |
| 115 |
> |
gotmat = raycont(r); /* hit local surface, evaluate */ |
| 116 |
|
else if (r->ro == &Aftplane) { |
| 117 |
< |
r->ro = NULL; |
| 117 |
> |
r->ro = NULL; /* hit aft clipping plane */ |
| 118 |
|
r->rot = FHUGE; |
| 119 |
|
} else if (sourcehit(r)) |
| 120 |
< |
gotmat = rayshade(r, r->ro->omod); |
| 120 |
> |
gotmat = rayshade(r, r->ro->omod); /* distant source */ |
| 121 |
|
|
| 122 |
|
if (r->ro != NULL && !gotmat) |
| 123 |
|
objerror(r->ro, USER, "material not found"); |
| 124 |
|
|
| 125 |
+ |
rayparticipate(r); /* for participating medium */ |
| 126 |
+ |
|
| 127 |
|
if (trace != NULL) |
| 128 |
|
(*trace)(r); /* trace execution */ |
| 129 |
|
} |
| 189 |
|
} |
| 190 |
|
depth--; |
| 191 |
|
return(gotmat); |
| 192 |
+ |
} |
| 193 |
+ |
|
| 194 |
+ |
|
| 195 |
+ |
rayparticipate(r) /* compute ray medium participation */ |
| 196 |
+ |
register RAY *r; |
| 197 |
+ |
{ |
| 198 |
+ |
COLOR ce, ca; |
| 199 |
+ |
double dist; |
| 200 |
+ |
double re, ge, be; |
| 201 |
+ |
|
| 202 |
+ |
if (intens(r->cext) <= 1./FHUGE) |
| 203 |
+ |
return; /* no medium */ |
| 204 |
+ |
if ((dist = r->rot) >= FHUGE) |
| 205 |
+ |
dist = 2.*thescene.cusize; /* what to use for infinity? */ |
| 206 |
+ |
if (r->crtype & SHADOW) |
| 207 |
+ |
dist *= 1. - salbedo; /* no scattering for sources */ |
| 208 |
+ |
if (dist <= FTINY) |
| 209 |
+ |
return; /* no effective ray travel */ |
| 210 |
+ |
re = dist*colval(r->cext,RED); |
| 211 |
+ |
ge = dist*colval(r->cext,GRN); |
| 212 |
+ |
be = dist*colval(r->cext,BLU); |
| 213 |
+ |
setcolor(ce, re>92. ? 0. : exp(-re), |
| 214 |
+ |
ge>92. ? 0. : exp(-ge), |
| 215 |
+ |
be>92. ? 0. : exp(-be)); |
| 216 |
+ |
multcolor(r->rcol, ce); /* path absorption */ |
| 217 |
+ |
if (r->albedo <= FTINY || r->crtype & SHADOW) |
| 218 |
+ |
return; /* no scattering */ |
| 219 |
+ |
setcolor(ca, salbedo*colval(ambval,RED)*(1.-colval(ce,RED)), |
| 220 |
+ |
salbedo*colval(ambval,GRN)*(1.-colval(ce,GRN)), |
| 221 |
+ |
salbedo*colval(ambval,BLU)*(1.-colval(ce,BLU))); |
| 222 |
+ |
addcolor(r->rcol, ca); /* ambient in scattering */ |
| 223 |
+ |
srcscatter(r); /* source in scattering */ |
| 224 |
|
} |
| 225 |
|
|
| 226 |
|
|
