1 |
greg |
1.1 |
#ifndef lint |
2 |
greg |
2.23 |
static const char RCSid[] = "$Id: ambcomp.c,v 2.22 2010/09/26 15:51:15 greg Exp $"; |
3 |
greg |
1.1 |
#endif |
4 |
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/* |
5 |
|
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* Routines to compute "ambient" values using Monte Carlo |
6 |
greg |
2.9 |
* |
7 |
|
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* Declarations of external symbols in ambient.h |
8 |
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*/ |
9 |
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10 |
greg |
2.10 |
#include "copyright.h" |
11 |
greg |
1.1 |
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12 |
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#include "ray.h" |
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14 |
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#include "ambient.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 |
2.15 |
void |
20 |
greg |
2.14 |
inithemi( /* initialize sampling hemisphere */ |
21 |
greg |
2.23 |
AMBHEMI *hp, |
22 |
greg |
2.16 |
COLOR ac, |
23 |
greg |
2.14 |
RAY *r, |
24 |
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double wt |
25 |
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) |
26 |
greg |
1.1 |
{ |
27 |
greg |
2.16 |
double d; |
28 |
greg |
2.23 |
int i; |
29 |
greg |
2.14 |
/* set number of divisions */ |
30 |
greg |
2.16 |
if (ambacc <= FTINY && |
31 |
greg |
2.20 |
wt > (d = 0.8*intens(ac)*r->rweight/(ambdiv*minweight))) |
32 |
greg |
2.16 |
wt = d; /* avoid ray termination */ |
33 |
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hp->nt = sqrt(ambdiv * wt / PI) + 0.5; |
34 |
greg |
2.14 |
i = ambacc > FTINY ? 3 : 1; /* minimum number of samples */ |
35 |
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if (hp->nt < i) |
36 |
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hp->nt = i; |
37 |
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hp->np = PI * hp->nt + 0.5; |
38 |
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/* set number of super-samples */ |
39 |
greg |
2.15 |
hp->ns = ambssamp * wt + 0.5; |
40 |
greg |
2.16 |
/* assign coefficient */ |
41 |
greg |
2.14 |
copycolor(hp->acoef, ac); |
42 |
greg |
2.16 |
d = 1.0/(hp->nt*hp->np); |
43 |
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scalecolor(hp->acoef, d); |
44 |
greg |
2.14 |
/* make axes */ |
45 |
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VCOPY(hp->uz, r->ron); |
46 |
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hp->uy[0] = hp->uy[1] = hp->uy[2] = 0.0; |
47 |
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for (i = 0; i < 3; i++) |
48 |
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if (hp->uz[i] < 0.6 && hp->uz[i] > -0.6) |
49 |
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break; |
50 |
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if (i >= 3) |
51 |
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error(CONSISTENCY, "bad ray direction in inithemi"); |
52 |
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hp->uy[i] = 1.0; |
53 |
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fcross(hp->ux, hp->uy, hp->uz); |
54 |
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normalize(hp->ux); |
55 |
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fcross(hp->uy, hp->uz, hp->ux); |
56 |
greg |
1.1 |
} |
57 |
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58 |
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59 |
greg |
2.9 |
int |
60 |
greg |
2.14 |
divsample( /* sample a division */ |
61 |
greg |
2.23 |
AMBSAMP *dp, |
62 |
greg |
2.14 |
AMBHEMI *h, |
63 |
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RAY *r |
64 |
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) |
65 |
greg |
1.1 |
{ |
66 |
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RAY ar; |
67 |
greg |
1.11 |
int hlist[3]; |
68 |
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double spt[2]; |
69 |
greg |
1.1 |
double xd, yd, zd; |
70 |
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double b2; |
71 |
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double phi; |
72 |
greg |
2.23 |
int i; |
73 |
greg |
2.15 |
/* ambient coefficient for weight */ |
74 |
greg |
2.16 |
if (ambacc > FTINY) |
75 |
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setcolor(ar.rcoef, AVGREFL, AVGREFL, AVGREFL); |
76 |
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else |
77 |
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copycolor(ar.rcoef, h->acoef); |
78 |
greg |
2.14 |
if (rayorigin(&ar, AMBIENT, r, ar.rcoef) < 0) |
79 |
greg |
1.4 |
return(-1); |
80 |
greg |
2.17 |
if (ambacc > FTINY) { |
81 |
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multcolor(ar.rcoef, h->acoef); |
82 |
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scalecolor(ar.rcoef, 1./AVGREFL); |
83 |
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} |
84 |
greg |
1.1 |
hlist[0] = r->rno; |
85 |
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hlist[1] = dp->t; |
86 |
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hlist[2] = dp->p; |
87 |
greg |
1.13 |
multisamp(spt, 2, urand(ilhash(hlist,3)+dp->n)); |
88 |
greg |
1.11 |
zd = sqrt((dp->t + spt[0])/h->nt); |
89 |
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phi = 2.0*PI * (dp->p + spt[1])/h->np; |
90 |
gwlarson |
2.8 |
xd = tcos(phi) * zd; |
91 |
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yd = tsin(phi) * zd; |
92 |
greg |
1.1 |
zd = sqrt(1.0 - zd*zd); |
93 |
greg |
1.2 |
for (i = 0; i < 3; i++) |
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ar.rdir[i] = xd*h->ux[i] + |
95 |
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yd*h->uy[i] + |
96 |
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zd*h->uz[i]; |
97 |
greg |
2.22 |
checknorm(ar.rdir); |
98 |
greg |
1.2 |
dimlist[ndims++] = dp->t*h->np + dp->p + 90171; |
99 |
greg |
1.1 |
rayvalue(&ar); |
100 |
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ndims--; |
101 |
greg |
2.16 |
multcolor(ar.rcol, ar.rcoef); /* apply coefficient */ |
102 |
greg |
1.1 |
addcolor(dp->v, ar.rcol); |
103 |
greg |
2.9 |
/* use rt to improve gradient calc */ |
104 |
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if (ar.rt > FTINY && ar.rt < FHUGE) |
105 |
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dp->r += 1.0/ar.rt; |
106 |
greg |
1.1 |
/* (re)initialize error */ |
107 |
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if (dp->n++) { |
108 |
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b2 = bright(dp->v)/dp->n - bright(ar.rcol); |
109 |
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b2 = b2*b2 + dp->k*((dp->n-1)*(dp->n-1)); |
110 |
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dp->k = b2/(dp->n*dp->n); |
111 |
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} else |
112 |
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dp->k = 0.0; |
113 |
greg |
1.4 |
return(0); |
114 |
greg |
1.1 |
} |
115 |
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116 |
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117 |
greg |
2.14 |
static int |
118 |
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ambcmp( /* decreasing order */ |
119 |
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const void *p1, |
120 |
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const void *p2 |
121 |
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) |
122 |
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{ |
123 |
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const AMBSAMP *d1 = (const AMBSAMP *)p1; |
124 |
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const AMBSAMP *d2 = (const AMBSAMP *)p2; |
125 |
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126 |
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if (d1->k < d2->k) |
127 |
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return(1); |
128 |
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if (d1->k > d2->k) |
129 |
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return(-1); |
130 |
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return(0); |
131 |
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} |
132 |
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133 |
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134 |
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static int |
135 |
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ambnorm( /* standard order */ |
136 |
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const void *p1, |
137 |
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const void *p2 |
138 |
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) |
139 |
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{ |
140 |
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const AMBSAMP *d1 = (const AMBSAMP *)p1; |
141 |
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const AMBSAMP *d2 = (const AMBSAMP *)p2; |
142 |
greg |
2.23 |
int c; |
143 |
greg |
2.14 |
|
144 |
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if ( (c = d1->t - d2->t) ) |
145 |
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return(c); |
146 |
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return(d1->p - d2->p); |
147 |
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} |
148 |
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149 |
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150 |
greg |
1.1 |
double |
151 |
greg |
2.14 |
doambient( /* compute ambient component */ |
152 |
greg |
2.23 |
COLOR rcol, |
153 |
greg |
2.14 |
RAY *r, |
154 |
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double wt, |
155 |
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FVECT pg, |
156 |
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FVECT dg |
157 |
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) |
158 |
greg |
1.1 |
{ |
159 |
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double b, d; |
160 |
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AMBHEMI hemi; |
161 |
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AMBSAMP *div; |
162 |
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AMBSAMP dnew; |
163 |
greg |
2.23 |
double acol[3]; |
164 |
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AMBSAMP *dp; |
165 |
greg |
1.1 |
double arad; |
166 |
greg |
2.19 |
int divcnt; |
167 |
greg |
2.23 |
int i, j; |
168 |
greg |
1.1 |
/* initialize hemisphere */ |
169 |
greg |
2.23 |
inithemi(&hemi, rcol, r, wt); |
170 |
greg |
2.19 |
divcnt = hemi.nt * hemi.np; |
171 |
greg |
2.17 |
/* initialize */ |
172 |
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if (pg != NULL) |
173 |
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pg[0] = pg[1] = pg[2] = 0.0; |
174 |
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if (dg != NULL) |
175 |
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dg[0] = dg[1] = dg[2] = 0.0; |
176 |
greg |
2.23 |
setcolor(rcol, 0.0, 0.0, 0.0); |
177 |
greg |
2.19 |
if (divcnt == 0) |
178 |
greg |
1.1 |
return(0.0); |
179 |
greg |
2.14 |
/* allocate super-samples */ |
180 |
greg |
2.15 |
if (hemi.ns > 0 || pg != NULL || dg != NULL) { |
181 |
greg |
2.19 |
div = (AMBSAMP *)malloc(divcnt*sizeof(AMBSAMP)); |
182 |
greg |
1.1 |
if (div == NULL) |
183 |
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error(SYSTEM, "out of memory in doambient"); |
184 |
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} else |
185 |
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div = NULL; |
186 |
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/* sample the divisions */ |
187 |
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arad = 0.0; |
188 |
greg |
2.23 |
acol[0] = acol[1] = acol[2] = 0.0; |
189 |
greg |
1.1 |
if ((dp = div) == NULL) |
190 |
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dp = &dnew; |
191 |
greg |
2.19 |
divcnt = 0; |
192 |
greg |
1.1 |
for (i = 0; i < hemi.nt; i++) |
193 |
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for (j = 0; j < hemi.np; j++) { |
194 |
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dp->t = i; dp->p = j; |
195 |
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setcolor(dp->v, 0.0, 0.0, 0.0); |
196 |
greg |
1.2 |
dp->r = 0.0; |
197 |
greg |
1.1 |
dp->n = 0; |
198 |
greg |
2.16 |
if (divsample(dp, &hemi, r) < 0) { |
199 |
greg |
2.19 |
if (div != NULL) |
200 |
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dp++; |
201 |
greg |
2.16 |
continue; |
202 |
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} |
203 |
greg |
2.6 |
arad += dp->r; |
204 |
greg |
2.19 |
divcnt++; |
205 |
greg |
1.1 |
if (div != NULL) |
206 |
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dp++; |
207 |
greg |
2.6 |
else |
208 |
greg |
1.1 |
addcolor(acol, dp->v); |
209 |
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} |
210 |
greg |
2.21 |
if (!divcnt) { |
211 |
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if (div != NULL) |
212 |
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free((void *)div); |
213 |
greg |
2.19 |
return(0.0); /* no samples taken */ |
214 |
greg |
2.21 |
} |
215 |
greg |
2.19 |
if (divcnt < hemi.nt*hemi.np) { |
216 |
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pg = dg = NULL; /* incomplete sampling */ |
217 |
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hemi.ns = 0; |
218 |
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} else if (arad > FTINY && divcnt/arad < minarad) { |
219 |
greg |
2.15 |
hemi.ns = 0; /* close enough */ |
220 |
greg |
2.19 |
} else if (hemi.ns > 0) { /* else perform super-sampling? */ |
221 |
greg |
1.4 |
comperrs(div, &hemi); /* compute errors */ |
222 |
greg |
2.19 |
qsort(div, divcnt, sizeof(AMBSAMP), ambcmp); /* sort divs */ |
223 |
greg |
1.1 |
/* super-sample */ |
224 |
greg |
2.15 |
for (i = hemi.ns; i > 0; i--) { |
225 |
schorsch |
2.11 |
dnew = *div; |
226 |
greg |
2.16 |
if (divsample(&dnew, &hemi, r) < 0) { |
227 |
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dp++; |
228 |
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continue; |
229 |
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} |
230 |
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dp = div; /* reinsert */ |
231 |
greg |
2.19 |
j = divcnt < i ? divcnt : i; |
232 |
greg |
1.1 |
while (--j > 0 && dnew.k < dp[1].k) { |
233 |
schorsch |
2.11 |
*dp = *(dp+1); |
234 |
greg |
1.1 |
dp++; |
235 |
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} |
236 |
schorsch |
2.11 |
*dp = dnew; |
237 |
greg |
1.1 |
} |
238 |
greg |
1.2 |
if (pg != NULL || dg != NULL) /* restore order */ |
239 |
greg |
2.19 |
qsort(div, divcnt, sizeof(AMBSAMP), ambnorm); |
240 |
greg |
1.1 |
} |
241 |
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/* compute returned values */ |
242 |
greg |
1.3 |
if (div != NULL) { |
243 |
greg |
2.19 |
arad = 0.0; /* note: divcnt may be < nt*np */ |
244 |
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for (i = hemi.nt*hemi.np, dp = div; i-- > 0; dp++) { |
245 |
greg |
1.3 |
arad += dp->r; |
246 |
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if (dp->n > 1) { |
247 |
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b = 1.0/dp->n; |
248 |
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scalecolor(dp->v, b); |
249 |
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dp->r *= b; |
250 |
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dp->n = 1; |
251 |
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} |
252 |
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addcolor(acol, dp->v); |
253 |
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} |
254 |
greg |
1.5 |
b = bright(acol); |
255 |
greg |
1.6 |
if (b > FTINY) { |
256 |
greg |
2.17 |
b = 1.0/b; /* compute & normalize gradient(s) */ |
257 |
greg |
1.6 |
if (pg != NULL) { |
258 |
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posgradient(pg, div, &hemi); |
259 |
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for (i = 0; i < 3; i++) |
260 |
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pg[i] *= b; |
261 |
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} |
262 |
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if (dg != NULL) { |
263 |
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dirgradient(dg, div, &hemi); |
264 |
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for (i = 0; i < 3; i++) |
265 |
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dg[i] *= b; |
266 |
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} |
267 |
greg |
1.5 |
} |
268 |
greg |
2.9 |
free((void *)div); |
269 |
greg |
1.3 |
} |
270 |
greg |
2.23 |
copycolor(rcol, acol); |
271 |
greg |
1.1 |
if (arad <= FTINY) |
272 |
greg |
1.16 |
arad = maxarad; |
273 |
greg |
2.3 |
else |
274 |
greg |
2.19 |
arad = (divcnt+hemi.ns)/arad; |
275 |
greg |
1.15 |
if (pg != NULL) { /* reduce radius if gradient large */ |
276 |
|
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d = DOT(pg,pg); |
277 |
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if (d*arad*arad > 1.0) |
278 |
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arad = 1.0/sqrt(d); |
279 |
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} |
280 |
greg |
1.16 |
if (arad < minarad) { |
281 |
greg |
1.1 |
arad = minarad; |
282 |
greg |
1.16 |
if (pg != NULL && d*arad*arad > 1.0) { /* cap gradient */ |
283 |
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d = 1.0/arad/sqrt(d); |
284 |
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for (i = 0; i < 3; i++) |
285 |
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pg[i] *= d; |
286 |
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} |
287 |
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} |
288 |
greg |
2.3 |
if ((arad /= sqrt(wt)) > maxarad) |
289 |
|
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arad = maxarad; |
290 |
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return(arad); |
291 |
greg |
1.1 |
} |
292 |
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293 |
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|
294 |
greg |
2.9 |
void |
295 |
greg |
2.14 |
comperrs( /* compute initial error estimates */ |
296 |
|
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AMBSAMP *da, /* assumes standard ordering */ |
297 |
greg |
2.23 |
AMBHEMI *hp |
298 |
greg |
2.14 |
) |
299 |
greg |
1.1 |
{ |
300 |
|
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double b, b2; |
301 |
|
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int i, j; |
302 |
greg |
2.23 |
AMBSAMP *dp; |
303 |
greg |
1.1 |
/* sum differences from neighbors */ |
304 |
|
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dp = da; |
305 |
|
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for (i = 0; i < hp->nt; i++) |
306 |
|
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for (j = 0; j < hp->np; j++) { |
307 |
greg |
1.6 |
#ifdef DEBUG |
308 |
|
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if (dp->t != i || dp->p != j) |
309 |
|
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error(CONSISTENCY, |
310 |
|
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"division order in comperrs"); |
311 |
|
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#endif |
312 |
greg |
1.1 |
b = bright(dp[0].v); |
313 |
|
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if (i > 0) { /* from above */ |
314 |
|
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b2 = bright(dp[-hp->np].v) - b; |
315 |
|
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b2 *= b2 * 0.25; |
316 |
|
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dp[0].k += b2; |
317 |
|
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dp[-hp->np].k += b2; |
318 |
|
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} |
319 |
|
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if (j > 0) { /* from behind */ |
320 |
|
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b2 = bright(dp[-1].v) - b; |
321 |
|
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b2 *= b2 * 0.25; |
322 |
|
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dp[0].k += b2; |
323 |
|
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dp[-1].k += b2; |
324 |
greg |
1.4 |
} else { /* around */ |
325 |
|
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b2 = bright(dp[hp->np-1].v) - b; |
326 |
greg |
1.1 |
b2 *= b2 * 0.25; |
327 |
|
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dp[0].k += b2; |
328 |
greg |
1.4 |
dp[hp->np-1].k += b2; |
329 |
greg |
1.1 |
} |
330 |
|
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dp++; |
331 |
|
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} |
332 |
|
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/* divide by number of neighbors */ |
333 |
|
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dp = da; |
334 |
|
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for (j = 0; j < hp->np; j++) /* top row */ |
335 |
|
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(dp++)->k *= 1.0/3.0; |
336 |
|
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if (hp->nt < 2) |
337 |
|
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return; |
338 |
|
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for (i = 1; i < hp->nt-1; i++) /* central region */ |
339 |
|
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for (j = 0; j < hp->np; j++) |
340 |
|
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(dp++)->k *= 0.25; |
341 |
|
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for (j = 0; j < hp->np; j++) /* bottom row */ |
342 |
|
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(dp++)->k *= 1.0/3.0; |
343 |
|
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} |
344 |
|
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|
345 |
|
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|
346 |
greg |
2.9 |
void |
347 |
greg |
2.14 |
posgradient( /* compute position gradient */ |
348 |
|
|
FVECT gv, |
349 |
|
|
AMBSAMP *da, /* assumes standard ordering */ |
350 |
greg |
2.23 |
AMBHEMI *hp |
351 |
greg |
2.14 |
) |
352 |
greg |
1.1 |
{ |
353 |
greg |
2.23 |
int i, j; |
354 |
greg |
2.2 |
double nextsine, lastsine, b, d; |
355 |
greg |
1.2 |
double mag0, mag1; |
356 |
|
|
double phi, cosp, sinp, xd, yd; |
357 |
greg |
2.23 |
AMBSAMP *dp; |
358 |
greg |
1.2 |
|
359 |
|
|
xd = yd = 0.0; |
360 |
|
|
for (j = 0; j < hp->np; j++) { |
361 |
|
|
dp = da + j; |
362 |
|
|
mag0 = mag1 = 0.0; |
363 |
greg |
2.2 |
lastsine = 0.0; |
364 |
greg |
1.2 |
for (i = 0; i < hp->nt; i++) { |
365 |
|
|
#ifdef DEBUG |
366 |
|
|
if (dp->t != i || dp->p != j) |
367 |
|
|
error(CONSISTENCY, |
368 |
|
|
"division order in posgradient"); |
369 |
|
|
#endif |
370 |
|
|
b = bright(dp->v); |
371 |
|
|
if (i > 0) { |
372 |
|
|
d = dp[-hp->np].r; |
373 |
|
|
if (dp[0].r > d) d = dp[0].r; |
374 |
greg |
2.2 |
/* sin(t)*cos(t)^2 */ |
375 |
|
|
d *= lastsine * (1.0 - (double)i/hp->nt); |
376 |
greg |
1.2 |
mag0 += d*(b - bright(dp[-hp->np].v)); |
377 |
|
|
} |
378 |
greg |
2.2 |
nextsine = sqrt((double)(i+1)/hp->nt); |
379 |
greg |
1.2 |
if (j > 0) { |
380 |
|
|
d = dp[-1].r; |
381 |
|
|
if (dp[0].r > d) d = dp[0].r; |
382 |
greg |
2.2 |
mag1 += d * (nextsine - lastsine) * |
383 |
|
|
(b - bright(dp[-1].v)); |
384 |
greg |
1.2 |
} else { |
385 |
|
|
d = dp[hp->np-1].r; |
386 |
|
|
if (dp[0].r > d) d = dp[0].r; |
387 |
greg |
2.2 |
mag1 += d * (nextsine - lastsine) * |
388 |
|
|
(b - bright(dp[hp->np-1].v)); |
389 |
greg |
1.2 |
} |
390 |
|
|
dp += hp->np; |
391 |
greg |
2.2 |
lastsine = nextsine; |
392 |
greg |
1.2 |
} |
393 |
greg |
2.2 |
mag0 *= 2.0*PI / hp->np; |
394 |
greg |
1.2 |
phi = 2.0*PI * (double)j/hp->np; |
395 |
gwlarson |
2.8 |
cosp = tcos(phi); sinp = tsin(phi); |
396 |
greg |
1.2 |
xd += mag0*cosp - mag1*sinp; |
397 |
|
|
yd += mag0*sinp + mag1*cosp; |
398 |
|
|
} |
399 |
|
|
for (i = 0; i < 3; i++) |
400 |
greg |
2.16 |
gv[i] = (xd*hp->ux[i] + yd*hp->uy[i])*(hp->nt*hp->np)/PI; |
401 |
greg |
1.1 |
} |
402 |
|
|
|
403 |
|
|
|
404 |
greg |
2.9 |
void |
405 |
greg |
2.14 |
dirgradient( /* compute direction gradient */ |
406 |
|
|
FVECT gv, |
407 |
|
|
AMBSAMP *da, /* assumes standard ordering */ |
408 |
greg |
2.23 |
AMBHEMI *hp |
409 |
greg |
2.14 |
) |
410 |
greg |
1.1 |
{ |
411 |
greg |
2.23 |
int i, j; |
412 |
greg |
1.2 |
double mag; |
413 |
|
|
double phi, xd, yd; |
414 |
greg |
2.23 |
AMBSAMP *dp; |
415 |
greg |
1.2 |
|
416 |
|
|
xd = yd = 0.0; |
417 |
|
|
for (j = 0; j < hp->np; j++) { |
418 |
|
|
dp = da + j; |
419 |
|
|
mag = 0.0; |
420 |
|
|
for (i = 0; i < hp->nt; i++) { |
421 |
|
|
#ifdef DEBUG |
422 |
|
|
if (dp->t != i || dp->p != j) |
423 |
|
|
error(CONSISTENCY, |
424 |
|
|
"division order in dirgradient"); |
425 |
|
|
#endif |
426 |
greg |
2.2 |
/* tan(t) */ |
427 |
|
|
mag += bright(dp->v)/sqrt(hp->nt/(i+.5) - 1.0); |
428 |
greg |
1.2 |
dp += hp->np; |
429 |
|
|
} |
430 |
|
|
phi = 2.0*PI * (j+.5)/hp->np + PI/2.0; |
431 |
gwlarson |
2.8 |
xd += mag * tcos(phi); |
432 |
|
|
yd += mag * tsin(phi); |
433 |
greg |
1.2 |
} |
434 |
|
|
for (i = 0; i < 3; i++) |
435 |
greg |
2.16 |
gv[i] = xd*hp->ux[i] + yd*hp->uy[i]; |
436 |
greg |
1.1 |
} |