51 |
|
#define MINCOS 0.997 /* minimum dot product for dispersion */ |
52 |
|
|
53 |
|
extern COLOR cextinction; /* global coefficient of extinction */ |
54 |
< |
extern double salbedo; /* global scattering albedo */ |
54 |
> |
extern COLOR salbedo; /* global scattering albedo */ |
55 |
|
|
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 |
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{ |
73 |
|
double cos1, cos2, nratio; |
74 |
|
COLOR ctrans; |
75 |
< |
double talb; |
75 |
> |
COLOR talb; |
76 |
|
double mabsorp; |
77 |
|
double refl, trans; |
78 |
|
FVECT dnorm; |
97 |
|
dnorm[0] = -dnorm[0]; |
98 |
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dnorm[1] = -dnorm[1]; |
99 |
|
dnorm[2] = -dnorm[2]; |
100 |
< |
setcolor(r->cext, -log(m->oargs.farg[0]*colval(r->pcol,RED)), |
101 |
< |
-log(m->oargs.farg[1]*colval(r->pcol,GRN)), |
102 |
< |
-log(m->oargs.farg[2]*colval(r->pcol,BLU))); |
103 |
< |
r->albedo = 0.; |
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 |
< |
-log(m->oargs.farg[4]*colval(r->pcol,RED)), |
108 |
< |
-log(m->oargs.farg[5]*colval(r->pcol,GRN)), |
109 |
< |
-log(m->oargs.farg[6]*colval(r->pcol,BLU))); |
110 |
< |
talb = 0.; |
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 |
< |
talb = salbedo; |
113 |
> |
copycolor(talb, salbedo); |
114 |
|
} |
115 |
|
} else { /* outside */ |
116 |
|
nratio = 1.0 / nratio; |
117 |
|
|
118 |
< |
setcolor(ctrans, -log(m->oargs.farg[0]*colval(r->pcol,RED)), |
119 |
< |
-log(m->oargs.farg[1]*colval(r->pcol,GRN)), |
120 |
< |
-log(m->oargs.farg[2]*colval(r->pcol,BLU))); |
121 |
< |
talb = 0.; |
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 |
< |
-log(m->oargs.farg[4]*colval(r->pcol,RED)), |
125 |
< |
-log(m->oargs.farg[5]*colval(r->pcol,GRN)), |
126 |
< |
-log(m->oargs.farg[6]*colval(r->pcol,BLU))); |
127 |
< |
r->albedo = 0.; |
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 |
|
} |
169 |
|
#endif |
170 |
|
{ |
171 |
|
copycolor(p.cext, ctrans); |
172 |
< |
p.albedo = talb; |
172 |
> |
copycolor(p.albedo, talb); |
173 |
|
rayvalue(&p); |
174 |
|
scalecolor(p.rcol, trans); |
175 |
|
addcolor(r->rcol, p.rcol); |