1 |
greg |
1.1 |
#ifndef lint |
2 |
greg |
2.11 |
static const char RCSid[] = "$Id: srcsamp.c,v 2.10 2003/07/21 22:30:19 schorsch Exp $"; |
3 |
greg |
1.1 |
#endif |
4 |
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/* |
5 |
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* Source sampling routines |
6 |
greg |
2.7 |
* |
7 |
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* External symbols declared in source.h |
8 |
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*/ |
9 |
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10 |
greg |
2.8 |
#include "copyright.h" |
11 |
greg |
1.1 |
|
12 |
greg |
1.4 |
#include "ray.h" |
13 |
greg |
1.1 |
|
14 |
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#include "source.h" |
15 |
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16 |
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#include "random.h" |
17 |
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18 |
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19 |
greg |
2.5 |
static int cyl_partit(), flt_partit(); |
20 |
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21 |
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22 |
greg |
1.1 |
double |
23 |
greg |
1.4 |
nextssamp(r, si) /* compute sample for source, rtn. distance */ |
24 |
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register RAY *r; /* origin is read, direction is set */ |
25 |
greg |
1.1 |
register SRCINDEX *si; /* source index (modified to current) */ |
26 |
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{ |
27 |
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int cent[3], size[3], parr[2]; |
28 |
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FVECT vpos; |
29 |
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double d; |
30 |
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register int i; |
31 |
greg |
2.2 |
nextsample: |
32 |
greg |
1.1 |
while (++si->sp >= si->np) { /* get next sample */ |
33 |
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if (++si->sn >= nsources) |
34 |
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return(0.0); /* no more */ |
35 |
greg |
1.7 |
if (source[si->sn].sflags & SSKIP) |
36 |
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si->np = 0; |
37 |
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else if (srcsizerat <= FTINY) |
38 |
greg |
1.4 |
nopart(si, r); |
39 |
greg |
1.1 |
else { |
40 |
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for (i = si->sn; source[i].sflags & SVIRTUAL; |
41 |
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i = source[i].sa.sv.sn) |
42 |
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; /* partition source */ |
43 |
greg |
1.4 |
(*sfun[source[i].so->otype].of->partit)(si, r); |
44 |
greg |
1.1 |
} |
45 |
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si->sp = -1; |
46 |
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} |
47 |
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/* get partition */ |
48 |
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cent[0] = cent[1] = cent[2] = 0; |
49 |
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size[0] = size[1] = size[2] = MAXSPART; |
50 |
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parr[0] = 0; parr[1] = si->sp; |
51 |
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if (!skipparts(cent, size, parr, si->spt)) |
52 |
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error(CONSISTENCY, "bad source partition in nextssamp"); |
53 |
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/* compute sample */ |
54 |
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if (dstrsrc > FTINY) { /* jitter sample */ |
55 |
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dimlist[ndims] = si->sn + 8831; |
56 |
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dimlist[ndims+1] = si->sp + 3109; |
57 |
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d = urand(ilhash(dimlist,ndims+2)+samplendx); |
58 |
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if (source[si->sn].sflags & SFLAT) { |
59 |
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multisamp(vpos, 2, d); |
60 |
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vpos[2] = 0.5; |
61 |
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} else |
62 |
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multisamp(vpos, 3, d); |
63 |
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for (i = 0; i < 3; i++) |
64 |
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vpos[i] = dstrsrc * (1. - 2.*vpos[i]) * |
65 |
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(double)size[i]/MAXSPART; |
66 |
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} else |
67 |
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vpos[0] = vpos[1] = vpos[2] = 0.0; |
68 |
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69 |
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for (i = 0; i < 3; i++) |
70 |
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vpos[i] += (double)cent[i]/MAXSPART; |
71 |
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/* compute direction */ |
72 |
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for (i = 0; i < 3; i++) |
73 |
greg |
1.4 |
r->rdir[i] = source[si->sn].sloc[i] + |
74 |
greg |
1.1 |
vpos[SU]*source[si->sn].ss[SU][i] + |
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vpos[SV]*source[si->sn].ss[SV][i] + |
76 |
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vpos[SW]*source[si->sn].ss[SW][i]; |
77 |
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78 |
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if (!(source[si->sn].sflags & SDISTANT)) |
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for (i = 0; i < 3; i++) |
80 |
greg |
1.4 |
r->rdir[i] -= r->rorg[i]; |
81 |
greg |
1.1 |
/* compute distance */ |
82 |
greg |
1.4 |
if ((d = normalize(r->rdir)) == 0.0) |
83 |
greg |
2.2 |
goto nextsample; /* at source! */ |
84 |
greg |
1.1 |
|
85 |
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/* compute sample size */ |
86 |
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if (source[si->sn].sflags & SFLAT) { |
87 |
greg |
2.6 |
si->dom = sflatform(si->sn, r->rdir); |
88 |
greg |
2.4 |
si->dom *= size[SU]*size[SV]/(MAXSPART*(double)MAXSPART); |
89 |
greg |
1.1 |
} else if (source[si->sn].sflags & SCYL) { |
90 |
greg |
2.6 |
si->dom = scylform(si->sn, r->rdir); |
91 |
greg |
2.4 |
si->dom *= size[SU]/(double)MAXSPART; |
92 |
greg |
1.1 |
} else { |
93 |
greg |
2.6 |
si->dom = size[SU]*size[SV]*(double)size[SW] / |
94 |
greg |
2.4 |
(MAXSPART*MAXSPART*(double)MAXSPART) ; |
95 |
greg |
1.1 |
} |
96 |
greg |
2.6 |
if (source[si->sn].sflags & SDISTANT) { |
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si->dom *= source[si->sn].ss2; |
98 |
greg |
1.1 |
return(FHUGE); |
99 |
greg |
2.6 |
} |
100 |
greg |
2.3 |
if (si->dom <= 1e-4) |
101 |
greg |
2.2 |
goto nextsample; /* behind source? */ |
102 |
greg |
2.6 |
si->dom *= source[si->sn].ss2/(d*d); |
103 |
greg |
1.1 |
return(d); /* sample OK, return distance */ |
104 |
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} |
105 |
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106 |
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107 |
greg |
2.7 |
int |
108 |
greg |
1.1 |
skipparts(ct, sz, pp, pt) /* skip to requested partition */ |
109 |
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int ct[3], sz[3]; /* center and size of partition (returned) */ |
110 |
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register int pp[2]; /* current index, number to skip (modified) */ |
111 |
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unsigned char *pt; /* partition array */ |
112 |
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{ |
113 |
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register int p; |
114 |
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/* check this partition */ |
115 |
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p = spart(pt, pp[0]); |
116 |
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pp[0]++; |
117 |
schorsch |
2.10 |
if (p == S0) { /* leaf partition */ |
118 |
greg |
1.1 |
if (pp[1]) { |
119 |
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pp[1]--; |
120 |
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return(0); /* not there yet */ |
121 |
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} else |
122 |
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return(1); /* we've arrived */ |
123 |
schorsch |
2.10 |
} |
124 |
greg |
1.1 |
/* else check lower */ |
125 |
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sz[p] >>= 1; |
126 |
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ct[p] -= sz[p]; |
127 |
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if (skipparts(ct, sz, pp, pt)) |
128 |
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return(1); /* return hit */ |
129 |
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/* else check upper */ |
130 |
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ct[p] += sz[p] << 1; |
131 |
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if (skipparts(ct, sz, pp, pt)) |
132 |
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return(1); /* return hit */ |
133 |
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/* else return to starting position */ |
134 |
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ct[p] -= sz[p]; |
135 |
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sz[p] <<= 1; |
136 |
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return(0); /* return miss */ |
137 |
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} |
138 |
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139 |
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140 |
greg |
2.7 |
void |
141 |
greg |
1.4 |
nopart(si, r) /* single source partition */ |
142 |
greg |
1.1 |
register SRCINDEX *si; |
143 |
greg |
1.4 |
RAY *r; |
144 |
greg |
1.1 |
{ |
145 |
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clrpart(si->spt); |
146 |
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setpart(si->spt, 0, S0); |
147 |
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si->np = 1; |
148 |
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} |
149 |
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150 |
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151 |
greg |
2.7 |
void |
152 |
greg |
1.4 |
cylpart(si, r) /* partition a cylinder */ |
153 |
greg |
1.1 |
SRCINDEX *si; |
154 |
greg |
1.4 |
register RAY *r; |
155 |
greg |
1.1 |
{ |
156 |
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double dist2, safedist2, dist2cent, rad2; |
157 |
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FVECT v; |
158 |
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register SRCREC *sp; |
159 |
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int pi; |
160 |
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/* first check point location */ |
161 |
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clrpart(si->spt); |
162 |
greg |
1.4 |
sp = source + si->sn; |
163 |
greg |
1.3 |
rad2 = 1.365 * DOT(sp->ss[SV],sp->ss[SV]); |
164 |
greg |
1.4 |
v[0] = r->rorg[0] - sp->sloc[0]; |
165 |
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v[1] = r->rorg[1] - sp->sloc[1]; |
166 |
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v[2] = r->rorg[2] - sp->sloc[2]; |
167 |
greg |
1.1 |
dist2 = DOT(v,sp->ss[SU]); |
168 |
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safedist2 = DOT(sp->ss[SU],sp->ss[SU]); |
169 |
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dist2 *= dist2 / safedist2; |
170 |
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dist2cent = DOT(v,v); |
171 |
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dist2 = dist2cent - dist2; |
172 |
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if (dist2 <= rad2) { /* point inside extended cylinder */ |
173 |
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si->np = 0; |
174 |
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return; |
175 |
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} |
176 |
greg |
1.4 |
safedist2 *= 4.*r->rweight*r->rweight/(srcsizerat*srcsizerat); |
177 |
greg |
1.5 |
if (dist2 <= 4.*rad2 || /* point too close to subdivide */ |
178 |
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dist2cent >= safedist2) { /* or too far */ |
179 |
greg |
1.1 |
setpart(si->spt, 0, S0); |
180 |
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si->np = 1; |
181 |
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return; |
182 |
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} |
183 |
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pi = 0; |
184 |
greg |
1.4 |
si->np = cyl_partit(r->rorg, si->spt, &pi, MAXSPART, |
185 |
greg |
1.1 |
sp->sloc, sp->ss[SU], safedist2); |
186 |
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} |
187 |
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188 |
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189 |
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static int |
190 |
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cyl_partit(ro, pt, pi, mp, cent, axis, d2) /* slice a cylinder */ |
191 |
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FVECT ro; |
192 |
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unsigned char *pt; |
193 |
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register int *pi; |
194 |
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int mp; |
195 |
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FVECT cent, axis; |
196 |
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double d2; |
197 |
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{ |
198 |
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FVECT newct, newax; |
199 |
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int npl, npu; |
200 |
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201 |
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if (mp < 2 || dist2(ro, cent) >= d2) { /* hit limit? */ |
202 |
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setpart(pt, *pi, S0); |
203 |
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(*pi)++; |
204 |
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return(1); |
205 |
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} |
206 |
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/* subdivide */ |
207 |
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setpart(pt, *pi, SU); |
208 |
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(*pi)++; |
209 |
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newax[0] = .5*axis[0]; |
210 |
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newax[1] = .5*axis[1]; |
211 |
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newax[2] = .5*axis[2]; |
212 |
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d2 *= 0.25; |
213 |
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/* lower half */ |
214 |
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newct[0] = cent[0] - newax[0]; |
215 |
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newct[1] = cent[1] - newax[1]; |
216 |
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newct[2] = cent[2] - newax[2]; |
217 |
greg |
1.2 |
npl = cyl_partit(ro, pt, pi, mp/2, newct, newax, d2); |
218 |
greg |
1.1 |
/* upper half */ |
219 |
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newct[0] = cent[0] + newax[0]; |
220 |
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newct[1] = cent[1] + newax[1]; |
221 |
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newct[2] = cent[2] + newax[2]; |
222 |
greg |
1.2 |
npu = cyl_partit(ro, pt, pi, mp/2, newct, newax, d2); |
223 |
greg |
1.1 |
/* return total */ |
224 |
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return(npl + npu); |
225 |
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} |
226 |
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227 |
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228 |
greg |
2.7 |
void |
229 |
greg |
1.4 |
flatpart(si, r) /* partition a flat source */ |
230 |
greg |
1.1 |
register SRCINDEX *si; |
231 |
greg |
1.5 |
register RAY *r; |
232 |
greg |
1.1 |
{ |
233 |
schorsch |
2.9 |
register RREAL *vp; |
234 |
greg |
1.5 |
FVECT v; |
235 |
greg |
1.1 |
double du2, dv2; |
236 |
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int pi; |
237 |
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238 |
greg |
1.5 |
clrpart(si->spt); |
239 |
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vp = source[si->sn].sloc; |
240 |
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v[0] = r->rorg[0] - vp[0]; |
241 |
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v[1] = r->rorg[1] - vp[1]; |
242 |
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v[2] = r->rorg[2] - vp[2]; |
243 |
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vp = source[si->sn].snorm; |
244 |
greg |
2.11 |
if (DOT(v,vp) <= 0.) { /* behind source */ |
245 |
greg |
1.5 |
si->np = 0; |
246 |
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return; |
247 |
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} |
248 |
greg |
1.4 |
dv2 = 2.*r->rweight/srcsizerat; |
249 |
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dv2 *= dv2; |
250 |
greg |
1.1 |
vp = source[si->sn].ss[SU]; |
251 |
greg |
1.4 |
du2 = dv2 * DOT(vp,vp); |
252 |
greg |
1.1 |
vp = source[si->sn].ss[SV]; |
253 |
greg |
1.4 |
dv2 *= DOT(vp,vp); |
254 |
greg |
1.1 |
pi = 0; |
255 |
greg |
1.4 |
si->np = flt_partit(r->rorg, si->spt, &pi, MAXSPART, |
256 |
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source[si->sn].sloc, |
257 |
greg |
1.1 |
source[si->sn].ss[SU], source[si->sn].ss[SV], du2, dv2); |
258 |
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} |
259 |
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260 |
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261 |
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static int |
262 |
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flt_partit(ro, pt, pi, mp, cent, u, v, du2, dv2) /* partition flatty */ |
263 |
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FVECT ro; |
264 |
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unsigned char *pt; |
265 |
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register int *pi; |
266 |
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int mp; |
267 |
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FVECT cent, u, v; |
268 |
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double du2, dv2; |
269 |
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{ |
270 |
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double d2; |
271 |
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FVECT newct, newax; |
272 |
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int npl, npu; |
273 |
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274 |
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if (mp < 2 || ((d2 = dist2(ro, cent)) >= du2 |
275 |
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&& d2 >= dv2)) { /* hit limit? */ |
276 |
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setpart(pt, *pi, S0); |
277 |
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(*pi)++; |
278 |
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return(1); |
279 |
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} |
280 |
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if (du2 > dv2) { /* subdivide in U */ |
281 |
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setpart(pt, *pi, SU); |
282 |
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(*pi)++; |
283 |
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newax[0] = .5*u[0]; |
284 |
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newax[1] = .5*u[1]; |
285 |
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newax[2] = .5*u[2]; |
286 |
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u = newax; |
287 |
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du2 *= 0.25; |
288 |
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} else { /* subdivide in V */ |
289 |
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setpart(pt, *pi, SV); |
290 |
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(*pi)++; |
291 |
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newax[0] = .5*v[0]; |
292 |
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newax[1] = .5*v[1]; |
293 |
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newax[2] = .5*v[2]; |
294 |
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v = newax; |
295 |
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dv2 *= 0.25; |
296 |
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} |
297 |
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/* lower half */ |
298 |
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newct[0] = cent[0] - newax[0]; |
299 |
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newct[1] = cent[1] - newax[1]; |
300 |
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newct[2] = cent[2] - newax[2]; |
301 |
greg |
1.2 |
npl = flt_partit(ro, pt, pi, mp/2, newct, u, v, du2, dv2); |
302 |
greg |
1.1 |
/* upper half */ |
303 |
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newct[0] = cent[0] + newax[0]; |
304 |
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newct[1] = cent[1] + newax[1]; |
305 |
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newct[2] = cent[2] + newax[2]; |
306 |
greg |
1.2 |
npu = flt_partit(ro, pt, pi, mp/2, newct, u, v, du2, dv2); |
307 |
greg |
1.1 |
/* return total */ |
308 |
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return(npl + npu); |
309 |
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} |
310 |
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311 |
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312 |
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double |
313 |
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scylform(sn, dir) /* compute cosine for cylinder's projection */ |
314 |
|
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int sn; |
315 |
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register FVECT dir; /* assume normalized */ |
316 |
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{ |
317 |
schorsch |
2.9 |
register RREAL *dv; |
318 |
greg |
1.1 |
double d; |
319 |
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320 |
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dv = source[sn].ss[SU]; |
321 |
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d = DOT(dir, dv); |
322 |
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d *= d / DOT(dv,dv); |
323 |
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return(sqrt(1. - d)); |
324 |
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} |