1 |
greg |
1.1 |
/* Copyright (c) 1991 Regents of the University of California */ |
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#ifndef lint |
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static char SCCSid[] = "$SunId$ LBL"; |
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#endif |
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/* |
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* Routines to compute "ambient" values using Monte Carlo |
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*/ |
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#include "ray.h" |
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#include "ambient.h" |
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#include "random.h" |
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typedef struct { |
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short t, p; /* theta, phi indices */ |
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COLOR v; /* value sum */ |
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greg |
1.2 |
float r; /* 1/distance sum */ |
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float k; /* variance for this division */ |
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greg |
1.1 |
int n; /* number of subsamples */ |
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greg |
1.2 |
} AMBSAMP; /* ambient sample division */ |
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greg |
1.1 |
|
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typedef struct { |
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FVECT ux, uy, uz; /* x, y and z axis directions */ |
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short nt, np; /* number of theta and phi directions */ |
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} AMBHEMI; /* ambient sample hemisphere */ |
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extern double sin(), cos(), sqrt(); |
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static int |
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ambcmp(d1, d2) /* decreasing order */ |
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AMBSAMP *d1, *d2; |
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{ |
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if (d1->k < d2->k) |
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return(1); |
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if (d1->k > d2->k) |
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return(-1); |
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return(0); |
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} |
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static int |
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ambnorm(d1, d2) /* standard order */ |
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AMBSAMP *d1, *d2; |
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{ |
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register int c; |
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51 |
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if (c = d1->t - d2->t) |
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return(c); |
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return(d1->p - d2->p); |
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} |
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divsample(dp, h, r) /* sample a division */ |
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register AMBSAMP *dp; |
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AMBHEMI *h; |
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RAY *r; |
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{ |
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RAY ar; |
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greg |
1.11 |
int hlist[3]; |
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double spt[2]; |
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greg |
1.1 |
double xd, yd, zd; |
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double b2; |
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double phi; |
68 |
greg |
1.2 |
register int i; |
69 |
greg |
1.1 |
|
70 |
greg |
1.12 |
if (rayorigin(&ar, r, AMBIENT, AVGREFL) < 0) |
71 |
greg |
1.4 |
return(-1); |
72 |
greg |
1.1 |
hlist[0] = r->rno; |
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hlist[1] = dp->t; |
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hlist[2] = dp->p; |
75 |
greg |
1.13 |
multisamp(spt, 2, urand(ilhash(hlist,3)+dp->n)); |
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greg |
1.11 |
zd = sqrt((dp->t + spt[0])/h->nt); |
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phi = 2.0*PI * (dp->p + spt[1])/h->np; |
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greg |
1.1 |
xd = cos(phi) * zd; |
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yd = sin(phi) * zd; |
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zd = sqrt(1.0 - zd*zd); |
81 |
greg |
1.2 |
for (i = 0; i < 3; i++) |
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ar.rdir[i] = xd*h->ux[i] + |
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yd*h->uy[i] + |
84 |
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zd*h->uz[i]; |
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dimlist[ndims++] = dp->t*h->np + dp->p + 90171; |
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greg |
1.1 |
rayvalue(&ar); |
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ndims--; |
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addcolor(dp->v, ar.rcol); |
89 |
greg |
1.8 |
if (ar.rt > FTINY && ar.rt < FHUGE) |
90 |
greg |
1.4 |
dp->r += 1.0/ar.rt; |
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greg |
1.1 |
/* (re)initialize error */ |
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if (dp->n++) { |
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b2 = bright(dp->v)/dp->n - bright(ar.rcol); |
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b2 = b2*b2 + dp->k*((dp->n-1)*(dp->n-1)); |
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dp->k = b2/(dp->n*dp->n); |
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} else |
97 |
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dp->k = 0.0; |
98 |
greg |
1.4 |
return(0); |
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greg |
1.1 |
} |
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double |
103 |
greg |
1.12 |
doambient(acol, r, wt, pg, dg) /* compute ambient component */ |
104 |
greg |
1.1 |
COLOR acol; |
105 |
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RAY *r; |
106 |
greg |
1.12 |
double wt; |
107 |
greg |
1.1 |
FVECT pg, dg; |
108 |
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{ |
109 |
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double b, d; |
110 |
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AMBHEMI hemi; |
111 |
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AMBSAMP *div; |
112 |
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AMBSAMP dnew; |
113 |
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register AMBSAMP *dp; |
114 |
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double arad; |
115 |
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int ndivs, ns; |
116 |
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register int i, j; |
117 |
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/* initialize color */ |
118 |
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setcolor(acol, 0.0, 0.0, 0.0); |
119 |
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/* initialize hemisphere */ |
120 |
greg |
1.12 |
inithemi(&hemi, r, wt); |
121 |
greg |
1.1 |
ndivs = hemi.nt * hemi.np; |
122 |
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if (ndivs == 0) |
123 |
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return(0.0); |
124 |
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/* set number of super-samples */ |
125 |
greg |
1.12 |
ns = ambssamp * wt + 0.5; |
126 |
greg |
1.1 |
if (ns > 0 || pg != NULL || dg != NULL) { |
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div = (AMBSAMP *)malloc(ndivs*sizeof(AMBSAMP)); |
128 |
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if (div == NULL) |
129 |
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error(SYSTEM, "out of memory in doambient"); |
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} else |
131 |
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div = NULL; |
132 |
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/* sample the divisions */ |
133 |
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arad = 0.0; |
134 |
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if ((dp = div) == NULL) |
135 |
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dp = &dnew; |
136 |
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for (i = 0; i < hemi.nt; i++) |
137 |
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for (j = 0; j < hemi.np; j++) { |
138 |
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dp->t = i; dp->p = j; |
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setcolor(dp->v, 0.0, 0.0, 0.0); |
140 |
greg |
1.2 |
dp->r = 0.0; |
141 |
greg |
1.1 |
dp->n = 0; |
142 |
greg |
1.4 |
if (divsample(dp, &hemi, r) < 0) |
143 |
greg |
1.1 |
goto oopsy; |
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if (div != NULL) |
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dp++; |
146 |
greg |
1.2 |
else { |
147 |
greg |
1.1 |
addcolor(acol, dp->v); |
148 |
greg |
1.2 |
arad += dp->r; |
149 |
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} |
150 |
greg |
1.1 |
} |
151 |
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if (ns > 0) { /* perform super-sampling */ |
152 |
greg |
1.4 |
comperrs(div, &hemi); /* compute errors */ |
153 |
greg |
1.1 |
qsort(div, ndivs, sizeof(AMBSAMP), ambcmp); /* sort divs */ |
154 |
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/* super-sample */ |
155 |
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for (i = ns; i > 0; i--) { |
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copystruct(&dnew, div); |
157 |
greg |
1.4 |
if (divsample(&dnew, &hemi, r) < 0) |
158 |
greg |
1.1 |
goto oopsy; |
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/* reinsert */ |
160 |
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dp = div; |
161 |
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j = ndivs < i ? ndivs : i; |
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while (--j > 0 && dnew.k < dp[1].k) { |
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copystruct(dp, dp+1); |
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dp++; |
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} |
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copystruct(dp, &dnew); |
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} |
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greg |
1.2 |
if (pg != NULL || dg != NULL) /* restore order */ |
169 |
greg |
1.1 |
qsort(div, ndivs, sizeof(AMBSAMP), ambnorm); |
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} |
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/* compute returned values */ |
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greg |
1.3 |
if (div != NULL) { |
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for (i = ndivs, dp = div; i-- > 0; dp++) { |
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arad += dp->r; |
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if (dp->n > 1) { |
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b = 1.0/dp->n; |
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scalecolor(dp->v, b); |
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dp->r *= b; |
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dp->n = 1; |
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} |
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addcolor(acol, dp->v); |
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} |
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greg |
1.5 |
b = bright(acol); |
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greg |
1.6 |
if (b > FTINY) { |
185 |
greg |
1.5 |
b = ndivs/b; |
186 |
greg |
1.6 |
if (pg != NULL) { |
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posgradient(pg, div, &hemi); |
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for (i = 0; i < 3; i++) |
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pg[i] *= b; |
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} |
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if (dg != NULL) { |
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dirgradient(dg, div, &hemi); |
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for (i = 0; i < 3; i++) |
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dg[i] *= b; |
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} |
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} else { |
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if (pg != NULL) |
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for (i = 0; i < 3; i++) |
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pg[i] = 0.0; |
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if (dg != NULL) |
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for (i = 0; i < 3; i++) |
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dg[i] = 0.0; |
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greg |
1.5 |
} |
204 |
greg |
1.1 |
free((char *)div); |
205 |
greg |
1.3 |
} |
206 |
greg |
1.1 |
b = 1.0/ndivs; |
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scalecolor(acol, b); |
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if (arad <= FTINY) |
209 |
greg |
1.16 |
arad = maxarad; |
210 |
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else { |
211 |
greg |
1.1 |
arad = (ndivs+ns)/arad; |
212 |
greg |
1.16 |
if (arad > maxarad) |
213 |
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arad = maxarad; |
214 |
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} |
215 |
greg |
1.15 |
if (pg != NULL) { /* reduce radius if gradient large */ |
216 |
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d = DOT(pg,pg); |
217 |
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if (d*arad*arad > 1.0) |
218 |
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arad = 1.0/sqrt(d); |
219 |
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} |
220 |
greg |
1.16 |
if (arad < minarad) { |
221 |
greg |
1.1 |
arad = minarad; |
222 |
greg |
1.16 |
if (pg != NULL && d*arad*arad > 1.0) { /* cap gradient */ |
223 |
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d = 1.0/arad/sqrt(d); |
224 |
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for (i = 0; i < 3; i++) |
225 |
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pg[i] *= d; |
226 |
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} |
227 |
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} |
228 |
greg |
1.15 |
return(arad/sqrt(wt)); |
229 |
greg |
1.1 |
oopsy: |
230 |
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if (div != NULL) |
231 |
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free((char *)div); |
232 |
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return(0.0); |
233 |
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} |
234 |
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235 |
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236 |
greg |
1.12 |
inithemi(hp, r, wt) /* initialize sampling hemisphere */ |
237 |
greg |
1.1 |
register AMBHEMI *hp; |
238 |
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RAY *r; |
239 |
greg |
1.12 |
double wt; |
240 |
greg |
1.1 |
{ |
241 |
greg |
1.2 |
register int i; |
242 |
greg |
1.1 |
/* set number of divisions */ |
243 |
greg |
1.14 |
if (wt < (.25*PI)/ambdiv+FTINY) { |
244 |
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hp->nt = hp->np = 0; |
245 |
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return; /* zero samples */ |
246 |
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} |
247 |
greg |
1.12 |
hp->nt = sqrt(ambdiv * wt / PI) + 0.5; |
248 |
greg |
1.14 |
hp->np = PI * hp->nt + 0.5; |
249 |
greg |
1.1 |
/* make axes */ |
250 |
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VCOPY(hp->uz, r->ron); |
251 |
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hp->uy[0] = hp->uy[1] = hp->uy[2] = 0.0; |
252 |
greg |
1.2 |
for (i = 0; i < 3; i++) |
253 |
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if (hp->uz[i] < 0.6 && hp->uz[i] > -0.6) |
254 |
greg |
1.1 |
break; |
255 |
greg |
1.2 |
if (i >= 3) |
256 |
greg |
1.1 |
error(CONSISTENCY, "bad ray direction in inithemi"); |
257 |
greg |
1.2 |
hp->uy[i] = 1.0; |
258 |
greg |
1.3 |
fcross(hp->ux, hp->uy, hp->uz); |
259 |
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normalize(hp->ux); |
260 |
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fcross(hp->uy, hp->uz, hp->ux); |
261 |
greg |
1.1 |
} |
262 |
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263 |
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264 |
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comperrs(da, hp) /* compute initial error estimates */ |
265 |
greg |
1.2 |
AMBSAMP *da; /* assumes standard ordering */ |
266 |
greg |
1.1 |
register AMBHEMI *hp; |
267 |
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{ |
268 |
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double b, b2; |
269 |
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int i, j; |
270 |
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register AMBSAMP *dp; |
271 |
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/* sum differences from neighbors */ |
272 |
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dp = da; |
273 |
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for (i = 0; i < hp->nt; i++) |
274 |
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for (j = 0; j < hp->np; j++) { |
275 |
greg |
1.6 |
#ifdef DEBUG |
276 |
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if (dp->t != i || dp->p != j) |
277 |
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error(CONSISTENCY, |
278 |
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"division order in comperrs"); |
279 |
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#endif |
280 |
greg |
1.1 |
b = bright(dp[0].v); |
281 |
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if (i > 0) { /* from above */ |
282 |
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b2 = bright(dp[-hp->np].v) - b; |
283 |
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b2 *= b2 * 0.25; |
284 |
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dp[0].k += b2; |
285 |
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dp[-hp->np].k += b2; |
286 |
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} |
287 |
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if (j > 0) { /* from behind */ |
288 |
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b2 = bright(dp[-1].v) - b; |
289 |
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b2 *= b2 * 0.25; |
290 |
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dp[0].k += b2; |
291 |
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dp[-1].k += b2; |
292 |
greg |
1.4 |
} else { /* around */ |
293 |
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b2 = bright(dp[hp->np-1].v) - b; |
294 |
greg |
1.1 |
b2 *= b2 * 0.25; |
295 |
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dp[0].k += b2; |
296 |
greg |
1.4 |
dp[hp->np-1].k += b2; |
297 |
greg |
1.1 |
} |
298 |
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dp++; |
299 |
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} |
300 |
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/* divide by number of neighbors */ |
301 |
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dp = da; |
302 |
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for (j = 0; j < hp->np; j++) /* top row */ |
303 |
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(dp++)->k *= 1.0/3.0; |
304 |
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if (hp->nt < 2) |
305 |
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return; |
306 |
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for (i = 1; i < hp->nt-1; i++) /* central region */ |
307 |
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for (j = 0; j < hp->np; j++) |
308 |
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(dp++)->k *= 0.25; |
309 |
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for (j = 0; j < hp->np; j++) /* bottom row */ |
310 |
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(dp++)->k *= 1.0/3.0; |
311 |
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} |
312 |
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313 |
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314 |
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posgradient(gv, da, hp) /* compute position gradient */ |
315 |
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FVECT gv; |
316 |
greg |
1.2 |
AMBSAMP *da; /* assumes standard ordering */ |
317 |
greg |
1.1 |
AMBHEMI *hp; |
318 |
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{ |
319 |
greg |
1.2 |
register int i, j; |
320 |
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double b, d; |
321 |
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double mag0, mag1; |
322 |
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double phi, cosp, sinp, xd, yd; |
323 |
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register AMBSAMP *dp; |
324 |
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325 |
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xd = yd = 0.0; |
326 |
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for (j = 0; j < hp->np; j++) { |
327 |
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dp = da + j; |
328 |
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mag0 = mag1 = 0.0; |
329 |
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for (i = 0; i < hp->nt; i++) { |
330 |
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#ifdef DEBUG |
331 |
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if (dp->t != i || dp->p != j) |
332 |
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error(CONSISTENCY, |
333 |
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"division order in posgradient"); |
334 |
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#endif |
335 |
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b = bright(dp->v); |
336 |
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if (i > 0) { |
337 |
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d = dp[-hp->np].r; |
338 |
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if (dp[0].r > d) d = dp[0].r; |
339 |
greg |
1.15 |
d *= 1.0 - (double)i/hp->nt; /* cos(t)^2 */ |
340 |
greg |
1.2 |
mag0 += d*(b - bright(dp[-hp->np].v)); |
341 |
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} |
342 |
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if (j > 0) { |
343 |
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d = dp[-1].r; |
344 |
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if (dp[0].r > d) d = dp[0].r; |
345 |
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mag1 += d*(b - bright(dp[-1].v)); |
346 |
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} else { |
347 |
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d = dp[hp->np-1].r; |
348 |
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if (dp[0].r > d) d = dp[0].r; |
349 |
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mag1 += d*(b - bright(dp[hp->np-1].v)); |
350 |
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} |
351 |
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dp += hp->np; |
352 |
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} |
353 |
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if (hp->nt > 1) { |
354 |
greg |
1.4 |
mag0 /= (double)hp->np; |
355 |
greg |
1.2 |
mag1 /= (double)hp->nt; |
356 |
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} |
357 |
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phi = 2.0*PI * (double)j/hp->np; |
358 |
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cosp = cos(phi); sinp = sin(phi); |
359 |
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xd += mag0*cosp - mag1*sinp; |
360 |
|
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yd += mag0*sinp + mag1*cosp; |
361 |
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} |
362 |
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for (i = 0; i < 3; i++) |
363 |
greg |
1.5 |
gv[i] = (xd*hp->ux[i] + yd*hp->uy[i])/PI; |
364 |
greg |
1.1 |
} |
365 |
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366 |
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367 |
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dirgradient(gv, da, hp) /* compute direction gradient */ |
368 |
|
|
FVECT gv; |
369 |
greg |
1.2 |
AMBSAMP *da; /* assumes standard ordering */ |
370 |
greg |
1.1 |
AMBHEMI *hp; |
371 |
|
|
{ |
372 |
greg |
1.2 |
register int i, j; |
373 |
|
|
double mag; |
374 |
|
|
double phi, xd, yd; |
375 |
|
|
register AMBSAMP *dp; |
376 |
|
|
|
377 |
|
|
xd = yd = 0.0; |
378 |
|
|
for (j = 0; j < hp->np; j++) { |
379 |
|
|
dp = da + j; |
380 |
|
|
mag = 0.0; |
381 |
|
|
for (i = 0; i < hp->nt; i++) { |
382 |
|
|
#ifdef DEBUG |
383 |
|
|
if (dp->t != i || dp->p != j) |
384 |
|
|
error(CONSISTENCY, |
385 |
|
|
"division order in dirgradient"); |
386 |
|
|
#endif |
387 |
greg |
1.15 |
mag += sqrt((i+.5)/hp->nt)*bright(dp->v); /* sin(t) */ |
388 |
greg |
1.2 |
dp += hp->np; |
389 |
|
|
} |
390 |
|
|
phi = 2.0*PI * (j+.5)/hp->np + PI/2.0; |
391 |
|
|
xd += mag * cos(phi); |
392 |
|
|
yd += mag * sin(phi); |
393 |
|
|
} |
394 |
|
|
for (i = 0; i < 3; i++) |
395 |
greg |
1.5 |
gv[i] = (xd*hp->ux[i] + yd*hp->uy[i])*PI/(hp->nt*hp->np); |
396 |
greg |
1.1 |
} |