1 |
greg |
1.1 |
#ifndef lint |
2 |
schorsch |
2.11 |
static const char RCSid[] = "$Id: ambcomp.c,v 2.10 2003/02/25 02:47:22 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 |
|
12 |
|
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#include "ray.h" |
13 |
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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 |
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static int |
20 |
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ambcmp(d1, d2) /* decreasing order */ |
21 |
|
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AMBSAMP *d1, *d2; |
22 |
|
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{ |
23 |
|
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if (d1->k < d2->k) |
24 |
|
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return(1); |
25 |
|
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if (d1->k > d2->k) |
26 |
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return(-1); |
27 |
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return(0); |
28 |
|
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} |
29 |
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|
30 |
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|
31 |
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static int |
32 |
|
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ambnorm(d1, d2) /* standard order */ |
33 |
|
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AMBSAMP *d1, *d2; |
34 |
|
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{ |
35 |
|
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register int c; |
36 |
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|
37 |
|
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if (c = d1->t - d2->t) |
38 |
|
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return(c); |
39 |
|
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return(d1->p - d2->p); |
40 |
|
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} |
41 |
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|
42 |
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|
43 |
greg |
2.9 |
int |
44 |
greg |
1.1 |
divsample(dp, h, r) /* sample a division */ |
45 |
|
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register AMBSAMP *dp; |
46 |
|
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AMBHEMI *h; |
47 |
|
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RAY *r; |
48 |
|
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{ |
49 |
|
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RAY ar; |
50 |
greg |
1.11 |
int hlist[3]; |
51 |
|
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double spt[2]; |
52 |
greg |
1.1 |
double xd, yd, zd; |
53 |
|
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double b2; |
54 |
|
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double phi; |
55 |
greg |
1.2 |
register int i; |
56 |
greg |
1.1 |
|
57 |
greg |
1.12 |
if (rayorigin(&ar, r, AMBIENT, AVGREFL) < 0) |
58 |
greg |
1.4 |
return(-1); |
59 |
greg |
1.1 |
hlist[0] = r->rno; |
60 |
|
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hlist[1] = dp->t; |
61 |
|
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hlist[2] = dp->p; |
62 |
greg |
1.13 |
multisamp(spt, 2, urand(ilhash(hlist,3)+dp->n)); |
63 |
greg |
1.11 |
zd = sqrt((dp->t + spt[0])/h->nt); |
64 |
|
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phi = 2.0*PI * (dp->p + spt[1])/h->np; |
65 |
gwlarson |
2.8 |
xd = tcos(phi) * zd; |
66 |
|
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yd = tsin(phi) * zd; |
67 |
greg |
1.1 |
zd = sqrt(1.0 - zd*zd); |
68 |
greg |
1.2 |
for (i = 0; i < 3; i++) |
69 |
|
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ar.rdir[i] = xd*h->ux[i] + |
70 |
|
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yd*h->uy[i] + |
71 |
|
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zd*h->uz[i]; |
72 |
|
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dimlist[ndims++] = dp->t*h->np + dp->p + 90171; |
73 |
greg |
1.1 |
rayvalue(&ar); |
74 |
|
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ndims--; |
75 |
|
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addcolor(dp->v, ar.rcol); |
76 |
greg |
2.9 |
/* use rt to improve gradient calc */ |
77 |
|
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if (ar.rt > FTINY && ar.rt < FHUGE) |
78 |
|
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dp->r += 1.0/ar.rt; |
79 |
greg |
1.1 |
/* (re)initialize error */ |
80 |
|
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if (dp->n++) { |
81 |
|
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b2 = bright(dp->v)/dp->n - bright(ar.rcol); |
82 |
|
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b2 = b2*b2 + dp->k*((dp->n-1)*(dp->n-1)); |
83 |
|
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dp->k = b2/(dp->n*dp->n); |
84 |
|
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} else |
85 |
|
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dp->k = 0.0; |
86 |
greg |
1.4 |
return(0); |
87 |
greg |
1.1 |
} |
88 |
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|
89 |
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|
90 |
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double |
91 |
greg |
1.12 |
doambient(acol, r, wt, pg, dg) /* compute ambient component */ |
92 |
greg |
1.1 |
COLOR acol; |
93 |
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RAY *r; |
94 |
greg |
1.12 |
double wt; |
95 |
greg |
1.1 |
FVECT pg, dg; |
96 |
|
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{ |
97 |
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double b, d; |
98 |
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AMBHEMI hemi; |
99 |
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AMBSAMP *div; |
100 |
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AMBSAMP dnew; |
101 |
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register AMBSAMP *dp; |
102 |
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double arad; |
103 |
|
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int ndivs, ns; |
104 |
|
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register int i, j; |
105 |
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/* initialize color */ |
106 |
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setcolor(acol, 0.0, 0.0, 0.0); |
107 |
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/* initialize hemisphere */ |
108 |
greg |
1.12 |
inithemi(&hemi, r, wt); |
109 |
greg |
1.1 |
ndivs = hemi.nt * hemi.np; |
110 |
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if (ndivs == 0) |
111 |
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return(0.0); |
112 |
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/* set number of super-samples */ |
113 |
greg |
1.12 |
ns = ambssamp * wt + 0.5; |
114 |
greg |
1.1 |
if (ns > 0 || pg != NULL || dg != NULL) { |
115 |
|
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div = (AMBSAMP *)malloc(ndivs*sizeof(AMBSAMP)); |
116 |
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if (div == NULL) |
117 |
|
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error(SYSTEM, "out of memory in doambient"); |
118 |
|
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} else |
119 |
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div = NULL; |
120 |
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/* sample the divisions */ |
121 |
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arad = 0.0; |
122 |
|
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if ((dp = div) == NULL) |
123 |
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dp = &dnew; |
124 |
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for (i = 0; i < hemi.nt; i++) |
125 |
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for (j = 0; j < hemi.np; j++) { |
126 |
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dp->t = i; dp->p = j; |
127 |
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setcolor(dp->v, 0.0, 0.0, 0.0); |
128 |
greg |
1.2 |
dp->r = 0.0; |
129 |
greg |
1.1 |
dp->n = 0; |
130 |
greg |
1.4 |
if (divsample(dp, &hemi, r) < 0) |
131 |
greg |
1.1 |
goto oopsy; |
132 |
greg |
2.6 |
arad += dp->r; |
133 |
greg |
1.1 |
if (div != NULL) |
134 |
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dp++; |
135 |
greg |
2.6 |
else |
136 |
greg |
1.1 |
addcolor(acol, dp->v); |
137 |
|
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} |
138 |
greg |
2.5 |
if (ns > 0 && arad > FTINY && ndivs/arad < minarad) |
139 |
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ns = 0; /* close enough */ |
140 |
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else if (ns > 0) { /* else perform super-sampling */ |
141 |
greg |
1.4 |
comperrs(div, &hemi); /* compute errors */ |
142 |
greg |
1.1 |
qsort(div, ndivs, sizeof(AMBSAMP), ambcmp); /* sort divs */ |
143 |
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/* super-sample */ |
144 |
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for (i = ns; i > 0; i--) { |
145 |
schorsch |
2.11 |
dnew = *div; |
146 |
greg |
1.4 |
if (divsample(&dnew, &hemi, r) < 0) |
147 |
greg |
1.1 |
goto oopsy; |
148 |
|
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/* reinsert */ |
149 |
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dp = div; |
150 |
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j = ndivs < i ? ndivs : i; |
151 |
|
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while (--j > 0 && dnew.k < dp[1].k) { |
152 |
schorsch |
2.11 |
*dp = *(dp+1); |
153 |
greg |
1.1 |
dp++; |
154 |
|
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} |
155 |
schorsch |
2.11 |
*dp = dnew; |
156 |
greg |
1.1 |
} |
157 |
greg |
1.2 |
if (pg != NULL || dg != NULL) /* restore order */ |
158 |
greg |
1.1 |
qsort(div, ndivs, sizeof(AMBSAMP), ambnorm); |
159 |
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} |
160 |
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/* compute returned values */ |
161 |
greg |
1.3 |
if (div != NULL) { |
162 |
greg |
2.6 |
arad = 0.0; |
163 |
greg |
1.3 |
for (i = ndivs, dp = div; i-- > 0; dp++) { |
164 |
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arad += dp->r; |
165 |
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if (dp->n > 1) { |
166 |
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b = 1.0/dp->n; |
167 |
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scalecolor(dp->v, b); |
168 |
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dp->r *= b; |
169 |
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dp->n = 1; |
170 |
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} |
171 |
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addcolor(acol, dp->v); |
172 |
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} |
173 |
greg |
1.5 |
b = bright(acol); |
174 |
greg |
1.6 |
if (b > FTINY) { |
175 |
greg |
1.5 |
b = ndivs/b; |
176 |
greg |
1.6 |
if (pg != NULL) { |
177 |
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posgradient(pg, div, &hemi); |
178 |
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for (i = 0; i < 3; i++) |
179 |
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pg[i] *= b; |
180 |
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} |
181 |
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if (dg != NULL) { |
182 |
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dirgradient(dg, div, &hemi); |
183 |
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for (i = 0; i < 3; i++) |
184 |
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dg[i] *= b; |
185 |
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} |
186 |
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} else { |
187 |
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if (pg != NULL) |
188 |
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for (i = 0; i < 3; i++) |
189 |
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pg[i] = 0.0; |
190 |
|
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if (dg != NULL) |
191 |
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for (i = 0; i < 3; i++) |
192 |
|
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dg[i] = 0.0; |
193 |
greg |
1.5 |
} |
194 |
greg |
2.9 |
free((void *)div); |
195 |
greg |
1.3 |
} |
196 |
greg |
1.1 |
b = 1.0/ndivs; |
197 |
|
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scalecolor(acol, b); |
198 |
|
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if (arad <= FTINY) |
199 |
greg |
1.16 |
arad = maxarad; |
200 |
greg |
2.3 |
else |
201 |
greg |
1.1 |
arad = (ndivs+ns)/arad; |
202 |
greg |
1.15 |
if (pg != NULL) { /* reduce radius if gradient large */ |
203 |
|
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d = DOT(pg,pg); |
204 |
|
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if (d*arad*arad > 1.0) |
205 |
|
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arad = 1.0/sqrt(d); |
206 |
|
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} |
207 |
greg |
1.16 |
if (arad < minarad) { |
208 |
greg |
1.1 |
arad = minarad; |
209 |
greg |
1.16 |
if (pg != NULL && d*arad*arad > 1.0) { /* cap gradient */ |
210 |
|
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d = 1.0/arad/sqrt(d); |
211 |
|
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for (i = 0; i < 3; i++) |
212 |
|
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pg[i] *= d; |
213 |
|
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} |
214 |
|
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} |
215 |
greg |
2.3 |
if ((arad /= sqrt(wt)) > maxarad) |
216 |
|
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arad = maxarad; |
217 |
|
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return(arad); |
218 |
greg |
1.1 |
oopsy: |
219 |
|
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if (div != NULL) |
220 |
greg |
2.9 |
free((void *)div); |
221 |
greg |
1.1 |
return(0.0); |
222 |
|
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} |
223 |
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|
224 |
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|
225 |
greg |
2.9 |
void |
226 |
greg |
1.12 |
inithemi(hp, r, wt) /* initialize sampling hemisphere */ |
227 |
greg |
1.1 |
register AMBHEMI *hp; |
228 |
|
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RAY *r; |
229 |
greg |
1.12 |
double wt; |
230 |
greg |
1.1 |
{ |
231 |
greg |
1.2 |
register int i; |
232 |
greg |
1.1 |
/* set number of divisions */ |
233 |
greg |
1.14 |
if (wt < (.25*PI)/ambdiv+FTINY) { |
234 |
|
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hp->nt = hp->np = 0; |
235 |
|
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return; /* zero samples */ |
236 |
|
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} |
237 |
greg |
1.12 |
hp->nt = sqrt(ambdiv * wt / PI) + 0.5; |
238 |
greg |
1.14 |
hp->np = PI * hp->nt + 0.5; |
239 |
greg |
1.1 |
/* make axes */ |
240 |
|
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VCOPY(hp->uz, r->ron); |
241 |
|
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hp->uy[0] = hp->uy[1] = hp->uy[2] = 0.0; |
242 |
greg |
1.2 |
for (i = 0; i < 3; i++) |
243 |
|
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if (hp->uz[i] < 0.6 && hp->uz[i] > -0.6) |
244 |
greg |
1.1 |
break; |
245 |
greg |
1.2 |
if (i >= 3) |
246 |
greg |
1.1 |
error(CONSISTENCY, "bad ray direction in inithemi"); |
247 |
greg |
1.2 |
hp->uy[i] = 1.0; |
248 |
greg |
1.3 |
fcross(hp->ux, hp->uy, hp->uz); |
249 |
|
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normalize(hp->ux); |
250 |
|
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fcross(hp->uy, hp->uz, hp->ux); |
251 |
greg |
1.1 |
} |
252 |
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|
253 |
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|
254 |
greg |
2.9 |
void |
255 |
greg |
1.1 |
comperrs(da, hp) /* compute initial error estimates */ |
256 |
greg |
1.2 |
AMBSAMP *da; /* assumes standard ordering */ |
257 |
greg |
1.1 |
register AMBHEMI *hp; |
258 |
|
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{ |
259 |
|
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double b, b2; |
260 |
|
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int i, j; |
261 |
|
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register AMBSAMP *dp; |
262 |
|
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/* sum differences from neighbors */ |
263 |
|
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dp = da; |
264 |
|
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for (i = 0; i < hp->nt; i++) |
265 |
|
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for (j = 0; j < hp->np; j++) { |
266 |
greg |
1.6 |
#ifdef DEBUG |
267 |
|
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if (dp->t != i || dp->p != j) |
268 |
|
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error(CONSISTENCY, |
269 |
|
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"division order in comperrs"); |
270 |
|
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#endif |
271 |
greg |
1.1 |
b = bright(dp[0].v); |
272 |
|
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if (i > 0) { /* from above */ |
273 |
|
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b2 = bright(dp[-hp->np].v) - b; |
274 |
|
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b2 *= b2 * 0.25; |
275 |
|
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dp[0].k += b2; |
276 |
|
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dp[-hp->np].k += b2; |
277 |
|
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} |
278 |
|
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if (j > 0) { /* from behind */ |
279 |
|
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b2 = bright(dp[-1].v) - b; |
280 |
|
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b2 *= b2 * 0.25; |
281 |
|
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dp[0].k += b2; |
282 |
|
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dp[-1].k += b2; |
283 |
greg |
1.4 |
} else { /* around */ |
284 |
|
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b2 = bright(dp[hp->np-1].v) - b; |
285 |
greg |
1.1 |
b2 *= b2 * 0.25; |
286 |
|
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dp[0].k += b2; |
287 |
greg |
1.4 |
dp[hp->np-1].k += b2; |
288 |
greg |
1.1 |
} |
289 |
|
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dp++; |
290 |
|
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} |
291 |
|
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/* divide by number of neighbors */ |
292 |
|
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dp = da; |
293 |
|
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for (j = 0; j < hp->np; j++) /* top row */ |
294 |
|
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(dp++)->k *= 1.0/3.0; |
295 |
|
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if (hp->nt < 2) |
296 |
|
|
return; |
297 |
|
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for (i = 1; i < hp->nt-1; i++) /* central region */ |
298 |
|
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for (j = 0; j < hp->np; j++) |
299 |
|
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(dp++)->k *= 0.25; |
300 |
|
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for (j = 0; j < hp->np; j++) /* bottom row */ |
301 |
|
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(dp++)->k *= 1.0/3.0; |
302 |
|
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} |
303 |
|
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|
304 |
|
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|
305 |
greg |
2.9 |
void |
306 |
greg |
1.1 |
posgradient(gv, da, hp) /* compute position gradient */ |
307 |
|
|
FVECT gv; |
308 |
greg |
1.2 |
AMBSAMP *da; /* assumes standard ordering */ |
309 |
greg |
2.2 |
register AMBHEMI *hp; |
310 |
greg |
1.1 |
{ |
311 |
greg |
1.2 |
register int i, j; |
312 |
greg |
2.2 |
double nextsine, lastsine, b, d; |
313 |
greg |
1.2 |
double mag0, mag1; |
314 |
|
|
double phi, cosp, sinp, xd, yd; |
315 |
|
|
register AMBSAMP *dp; |
316 |
|
|
|
317 |
|
|
xd = yd = 0.0; |
318 |
|
|
for (j = 0; j < hp->np; j++) { |
319 |
|
|
dp = da + j; |
320 |
|
|
mag0 = mag1 = 0.0; |
321 |
greg |
2.2 |
lastsine = 0.0; |
322 |
greg |
1.2 |
for (i = 0; i < hp->nt; i++) { |
323 |
|
|
#ifdef DEBUG |
324 |
|
|
if (dp->t != i || dp->p != j) |
325 |
|
|
error(CONSISTENCY, |
326 |
|
|
"division order in posgradient"); |
327 |
|
|
#endif |
328 |
|
|
b = bright(dp->v); |
329 |
|
|
if (i > 0) { |
330 |
|
|
d = dp[-hp->np].r; |
331 |
|
|
if (dp[0].r > d) d = dp[0].r; |
332 |
greg |
2.2 |
/* sin(t)*cos(t)^2 */ |
333 |
|
|
d *= lastsine * (1.0 - (double)i/hp->nt); |
334 |
greg |
1.2 |
mag0 += d*(b - bright(dp[-hp->np].v)); |
335 |
|
|
} |
336 |
greg |
2.2 |
nextsine = sqrt((double)(i+1)/hp->nt); |
337 |
greg |
1.2 |
if (j > 0) { |
338 |
|
|
d = dp[-1].r; |
339 |
|
|
if (dp[0].r > d) d = dp[0].r; |
340 |
greg |
2.2 |
mag1 += d * (nextsine - lastsine) * |
341 |
|
|
(b - bright(dp[-1].v)); |
342 |
greg |
1.2 |
} else { |
343 |
|
|
d = dp[hp->np-1].r; |
344 |
|
|
if (dp[0].r > d) d = dp[0].r; |
345 |
greg |
2.2 |
mag1 += d * (nextsine - lastsine) * |
346 |
|
|
(b - bright(dp[hp->np-1].v)); |
347 |
greg |
1.2 |
} |
348 |
|
|
dp += hp->np; |
349 |
greg |
2.2 |
lastsine = nextsine; |
350 |
greg |
1.2 |
} |
351 |
greg |
2.2 |
mag0 *= 2.0*PI / hp->np; |
352 |
greg |
1.2 |
phi = 2.0*PI * (double)j/hp->np; |
353 |
gwlarson |
2.8 |
cosp = tcos(phi); sinp = tsin(phi); |
354 |
greg |
1.2 |
xd += mag0*cosp - mag1*sinp; |
355 |
|
|
yd += mag0*sinp + mag1*cosp; |
356 |
|
|
} |
357 |
|
|
for (i = 0; i < 3; i++) |
358 |
greg |
1.5 |
gv[i] = (xd*hp->ux[i] + yd*hp->uy[i])/PI; |
359 |
greg |
1.1 |
} |
360 |
|
|
|
361 |
|
|
|
362 |
greg |
2.9 |
void |
363 |
greg |
1.1 |
dirgradient(gv, da, hp) /* compute direction gradient */ |
364 |
|
|
FVECT gv; |
365 |
greg |
1.2 |
AMBSAMP *da; /* assumes standard ordering */ |
366 |
greg |
2.2 |
register AMBHEMI *hp; |
367 |
greg |
1.1 |
{ |
368 |
greg |
1.2 |
register int i, j; |
369 |
|
|
double mag; |
370 |
|
|
double phi, xd, yd; |
371 |
|
|
register AMBSAMP *dp; |
372 |
|
|
|
373 |
|
|
xd = yd = 0.0; |
374 |
|
|
for (j = 0; j < hp->np; j++) { |
375 |
|
|
dp = da + j; |
376 |
|
|
mag = 0.0; |
377 |
|
|
for (i = 0; i < hp->nt; i++) { |
378 |
|
|
#ifdef DEBUG |
379 |
|
|
if (dp->t != i || dp->p != j) |
380 |
|
|
error(CONSISTENCY, |
381 |
|
|
"division order in dirgradient"); |
382 |
|
|
#endif |
383 |
greg |
2.2 |
/* tan(t) */ |
384 |
|
|
mag += bright(dp->v)/sqrt(hp->nt/(i+.5) - 1.0); |
385 |
greg |
1.2 |
dp += hp->np; |
386 |
|
|
} |
387 |
|
|
phi = 2.0*PI * (j+.5)/hp->np + PI/2.0; |
388 |
gwlarson |
2.8 |
xd += mag * tcos(phi); |
389 |
|
|
yd += mag * tsin(phi); |
390 |
greg |
1.2 |
} |
391 |
|
|
for (i = 0; i < 3; i++) |
392 |
greg |
2.2 |
gv[i] = (xd*hp->ux[i] + yd*hp->uy[i])/(hp->nt*hp->np); |
393 |
greg |
1.1 |
} |