| 50 |
|
|
| 51 |
|
#define MINCOS 0.997 /* minimum dot product for dispersion */ |
| 52 |
|
|
| 53 |
+ |
extern COLOR cextinction; /* global coefficient of extinction */ |
| 54 |
+ |
extern COLOR salbedo; /* global scattering albedo */ |
| 55 |
|
|
| 56 |
< |
m_dielectric(m, r) /* color a ray which hit something transparent */ |
| 56 |
> |
|
| 57 |
> |
static double |
| 58 |
> |
mylog(x) /* special log for extinction coefficients */ |
| 59 |
> |
double x; |
| 60 |
> |
{ |
| 61 |
> |
if (x < 1e-40) |
| 62 |
> |
return(-100.); |
| 63 |
> |
if (x >= 1.) |
| 64 |
> |
return(0.); |
| 65 |
> |
return(log(x)); |
| 66 |
> |
} |
| 67 |
> |
|
| 68 |
> |
|
| 69 |
> |
m_dielectric(m, r) /* color a ray which hit a dielectric interface */ |
| 70 |
|
OBJREC *m; |
| 71 |
|
register RAY *r; |
| 72 |
|
{ |
| 73 |
|
double cos1, cos2, nratio; |
| 74 |
< |
COLOR mcolor; |
| 74 |
> |
COLOR ctrans; |
| 75 |
> |
COLOR talb; |
| 76 |
|
double mabsorp; |
| 77 |
|
double refl, trans; |
| 78 |
|
FVECT dnorm; |
| 97 |
|
dnorm[0] = -dnorm[0]; |
| 98 |
|
dnorm[1] = -dnorm[1]; |
| 99 |
|
dnorm[2] = -dnorm[2]; |
| 100 |
< |
setcolor(mcolor, pow(m->oargs.farg[0], r->rot), |
| 101 |
< |
pow(m->oargs.farg[1], r->rot), |
| 102 |
< |
pow(m->oargs.farg[2], r->rot)); |
| 103 |
< |
multcolor(mcolor, r->pcol); /* modify */ |
| 100 |
> |
setcolor(r->cext, -mylog(m->oargs.farg[0]*colval(r->pcol,RED)), |
| 101 |
> |
-mylog(m->oargs.farg[1]*colval(r->pcol,GRN)), |
| 102 |
> |
-mylog(m->oargs.farg[2]*colval(r->pcol,BLU))); |
| 103 |
> |
setcolor(r->albedo, 0., 0., 0.); |
| 104 |
> |
r->gecc = 0.; |
| 105 |
> |
if (m->otype == MAT_INTERFACE) { |
| 106 |
> |
setcolor(ctrans, |
| 107 |
> |
-mylog(m->oargs.farg[4]*colval(r->pcol,RED)), |
| 108 |
> |
-mylog(m->oargs.farg[5]*colval(r->pcol,GRN)), |
| 109 |
> |
-mylog(m->oargs.farg[6]*colval(r->pcol,BLU))); |
| 110 |
> |
setcolor(talb, 0., 0., 0.); |
| 111 |
> |
} else { |
| 112 |
> |
copycolor(ctrans, cextinction); |
| 113 |
> |
copycolor(talb, salbedo); |
| 114 |
> |
} |
| 115 |
|
} else { /* outside */ |
| 116 |
|
nratio = 1.0 / nratio; |
| 117 |
< |
if (m->otype == MAT_INTERFACE) |
| 118 |
< |
setcolor(mcolor, pow(m->oargs.farg[4], r->rot), |
| 119 |
< |
pow(m->oargs.farg[5], r->rot), |
| 120 |
< |
pow(m->oargs.farg[6], r->rot)); |
| 121 |
< |
else |
| 122 |
< |
setcolor(mcolor, 1.0, 1.0, 1.0); |
| 117 |
> |
|
| 118 |
> |
setcolor(ctrans, -mylog(m->oargs.farg[0]*colval(r->pcol,RED)), |
| 119 |
> |
-mylog(m->oargs.farg[1]*colval(r->pcol,GRN)), |
| 120 |
> |
-mylog(m->oargs.farg[2]*colval(r->pcol,BLU))); |
| 121 |
> |
setcolor(talb, 0., 0., 0.); |
| 122 |
> |
if (m->otype == MAT_INTERFACE) { |
| 123 |
> |
setcolor(r->cext, |
| 124 |
> |
-mylog(m->oargs.farg[4]*colval(r->pcol,RED)), |
| 125 |
> |
-mylog(m->oargs.farg[5]*colval(r->pcol,GRN)), |
| 126 |
> |
-mylog(m->oargs.farg[6]*colval(r->pcol,BLU))); |
| 127 |
> |
setcolor(r->albedo, 0., 0., 0.); |
| 128 |
> |
r->gecc = 0.; |
| 129 |
> |
} |
| 130 |
|
} |
| 131 |
< |
mabsorp = bright(mcolor); |
| 131 |
> |
mabsorp = exp(-bright(r->cext)*r->rot); /* approximate */ |
| 132 |
|
|
| 133 |
|
d2 = 1.0 - nratio*nratio*(1.0 - cos1*cos1); /* compute cos theta2 */ |
| 134 |
|
|
| 149 |
|
d1 = (d1 - d2) / (d1 + d2); |
| 150 |
|
refl += d1 * d1; |
| 151 |
|
|
| 152 |
< |
refl /= 2.0; |
| 152 |
> |
refl *= 0.5; |
| 153 |
|
trans = 1.0 - refl; |
| 154 |
|
|
| 155 |
|
if (rayorigin(&p, r, REFRACTED, mabsorp*trans) == 0) { |
| 168 |
|
|| !disperse(m, r, p.rdir, trans)) |
| 169 |
|
#endif |
| 170 |
|
{ |
| 171 |
+ |
copycolor(p.cext, ctrans); |
| 172 |
+ |
copycolor(p.albedo, talb); |
| 173 |
|
rayvalue(&p); |
| 174 |
|
scalecolor(p.rcol, trans); |
| 175 |
|
addcolor(r->rcol, p.rcol); |
| 191 |
|
scalecolor(p.rcol, refl); /* color contribution */ |
| 192 |
|
addcolor(r->rcol, p.rcol); |
| 193 |
|
} |
| 194 |
< |
|
| 159 |
< |
multcolor(r->rcol, mcolor); /* multiply by transmittance */ |
| 160 |
< |
|
| 194 |
> |
/* rayvalue() computes absorption */ |
| 195 |
|
return(1); |
| 196 |
|
} |
| 197 |
|
|
