51 |
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#define MINCOS 0.997 /* minimum dot product for dispersion */ |
52 |
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|
53 |
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extern COLOR cextinction; /* global coefficient of extinction */ |
54 |
< |
extern double salbedo; /* global scattering albedo */ |
54 |
> |
extern COLOR salbedo; /* global scattering albedo */ |
55 |
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|
56 |
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|
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 |
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m_dielectric(m, r) /* color a ray which hit a dielectric interface */ |
70 |
|
OBJREC *m; |
71 |
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register RAY *r; |
72 |
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{ |
73 |
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double cos1, cos2, nratio; |
74 |
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COLOR ctrans; |
75 |
< |
double talb; |
75 |
> |
COLOR talb; |
76 |
|
double mabsorp; |
77 |
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double refl, trans; |
78 |
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FVECT dnorm; |
97 |
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dnorm[0] = -dnorm[0]; |
98 |
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dnorm[1] = -dnorm[1]; |
99 |
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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 |
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r->gecc = 0.; |
105 |
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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 |
|
} |
131 |
< |
mabsorp = exp(-bright(r->cext)*r->rot); /* approximate */ |
131 |
> |
/* estimate absorption */ |
132 |
> |
mabsorp = colval(r->cext,RED) < colval(r->cext,GRN) ? |
133 |
> |
colval(r->cext,RED) : colval(r->cext,GRN); |
134 |
> |
if (colval(r->cext,BLU) < mabsorp) mabsorp = colval(r->cext,BLU); |
135 |
> |
if (mabsorp > 0.) |
136 |
> |
mabsorp = exp(-mabsorp*r->rot); /* conservative */ |
137 |
> |
else |
138 |
> |
mabsorp = 1.0; |
139 |
|
|
140 |
|
d2 = 1.0 - nratio*nratio*(1.0 - cos1*cos1); /* compute cos theta2 */ |
141 |
|
|
172 |
|
|| r->crtype & SHADOW |
173 |
|
|| !directvis |
174 |
|
|| m->oargs.farg[4] == 0.0 |
175 |
< |
|| !disperse(m, r, p.rdir, trans)) |
175 |
> |
|| !disperse(m, r, p.rdir, |
176 |
> |
trans, ctrans, talb)) |
177 |
|
#endif |
178 |
|
{ |
179 |
|
copycolor(p.cext, ctrans); |
180 |
< |
p.albedo = talb; |
180 |
> |
copycolor(p.albedo, talb); |
181 |
|
rayvalue(&p); |
182 |
|
scalecolor(p.rcol, trans); |
183 |
|
addcolor(r->rcol, p.rcol); |
207 |
|
#ifdef DISPERSE |
208 |
|
|
209 |
|
static |
210 |
< |
disperse(m, r, vt, tr) /* check light sources for dispersion */ |
210 |
> |
disperse(m, r, vt, tr, cet, abt) /* check light sources for dispersion */ |
211 |
|
OBJREC *m; |
212 |
|
RAY *r; |
213 |
|
FVECT vt; |
214 |
|
double tr; |
215 |
+ |
COLOR cet, abt; |
216 |
|
{ |
217 |
|
RAY sray, *entray; |
218 |
|
FVECT v1, v2, n1, n2; |
298 |
|
if (l1 > MAXLAMBDA || l1 < MINLAMBDA) /* not visible */ |
299 |
|
continue; |
300 |
|
/* trace source ray */ |
301 |
+ |
copycolor(sray.cext, cet); |
302 |
+ |
copycolor(sray.albedo, abt); |
303 |
|
normalize(sray.rdir); |
304 |
|
rayvalue(&sray); |
305 |
|
if (bright(sray.rcol) <= FTINY) /* missed it */ |