| 1 |
#ifndef lint |
| 2 |
static const char RCSid[] = "$Id: ambcomp.c,v 2.25 2014/04/11 20:31:37 greg Exp $"; |
| 3 |
#endif |
| 4 |
/* |
| 5 |
* Routines to compute "ambient" values using Monte Carlo |
| 6 |
* |
| 7 |
* Declarations of external symbols in ambient.h |
| 8 |
*/ |
| 9 |
|
| 10 |
#include "copyright.h" |
| 11 |
|
| 12 |
#include "ray.h" |
| 13 |
#include "ambient.h" |
| 14 |
#include "random.h" |
| 15 |
|
| 16 |
#ifdef NEWAMB |
| 17 |
|
| 18 |
extern void SDsquare2disk(double ds[2], double seedx, double seedy); |
| 19 |
|
| 20 |
typedef struct { |
| 21 |
RAY *rp; /* originating ray sample */ |
| 22 |
FVECT ux, uy; /* tangent axis directions */ |
| 23 |
int ns; /* number of samples per axis */ |
| 24 |
COLOR acoef; /* division contribution coefficient */ |
| 25 |
struct s_ambsamp { |
| 26 |
COLOR v; /* hemisphere sample value */ |
| 27 |
float p[3]; /* intersection point */ |
| 28 |
} sa[1]; /* sample array (extends struct) */ |
| 29 |
} AMBHEMI; /* ambient sample hemisphere */ |
| 30 |
|
| 31 |
#define ambsamp(h,i,j) (h)->sa[(i)*(h)->ns + (j)] |
| 32 |
|
| 33 |
|
| 34 |
static AMBHEMI * |
| 35 |
inithemi( /* initialize sampling hemisphere */ |
| 36 |
COLOR ac, |
| 37 |
RAY *r, |
| 38 |
double wt |
| 39 |
) |
| 40 |
{ |
| 41 |
AMBHEMI *hp; |
| 42 |
double d; |
| 43 |
int n, i; |
| 44 |
/* set number of divisions */ |
| 45 |
if (ambacc <= FTINY && |
| 46 |
wt > (d = 0.8*intens(ac)*r->rweight/(ambdiv*minweight))) |
| 47 |
wt = d; /* avoid ray termination */ |
| 48 |
n = sqrt(ambdiv * wt) + 0.5; |
| 49 |
i = 1 + 4*(ambacc > FTINY); /* minimum number of samples */ |
| 50 |
if (n < i) |
| 51 |
n = i; |
| 52 |
/* allocate sampling array */ |
| 53 |
hp = (AMBHEMI *)malloc(sizeof(AMBHEMI) + |
| 54 |
sizeof(struct s_ambsamp)*(n*n - 1)); |
| 55 |
if (hp == NULL) |
| 56 |
return(NULL); |
| 57 |
hp->rp = r; |
| 58 |
hp->ns = n; |
| 59 |
/* assign coefficient */ |
| 60 |
copycolor(hp->acoef, ac); |
| 61 |
d = 1.0/(n*n); |
| 62 |
scalecolor(hp->acoef, d); |
| 63 |
/* make tangent axes */ |
| 64 |
hp->uy[0] = hp->uy[1] = hp->uy[2] = 0.0; |
| 65 |
for (i = 0; i < 3; i++) |
| 66 |
if (r->rn[i] < 0.6 && r->rn[i] > -0.6) |
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break; |
| 68 |
if (i >= 3) |
| 69 |
error(CONSISTENCY, "bad ray direction in inithemi()"); |
| 70 |
hp->uy[i] = 1.0; |
| 71 |
VCROSS(hp->ux, hp->uy, r->rn); |
| 72 |
normalize(hp->ux); |
| 73 |
VCROSS(hp->uy, r->rn, hp->ux); |
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/* we're ready to sample */ |
| 75 |
return(hp); |
| 76 |
} |
| 77 |
|
| 78 |
|
| 79 |
static int |
| 80 |
ambsample( /* sample an ambient direction */ |
| 81 |
AMBHEMI *hp, |
| 82 |
int i, |
| 83 |
int j, |
| 84 |
) |
| 85 |
{ |
| 86 |
struct s_ambsamp *ap = &ambsamp(hp,i,j); |
| 87 |
RAY ar; |
| 88 |
int hlist[3]; |
| 89 |
double spt[2], dz; |
| 90 |
int ii; |
| 91 |
/* ambient coefficient for weight */ |
| 92 |
if (ambacc > FTINY) |
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setcolor(ar.rcoef, AVGREFL, AVGREFL, AVGREFL); |
| 94 |
else |
| 95 |
copycolor(ar.rcoef, hp->acoef); |
| 96 |
if (rayorigin(&ar, AMBIENT, hp->rp, ar.rcoef) < 0) { |
| 97 |
setcolor(ap->v, 0., 0., 0.); |
| 98 |
ap->r = 0.; |
| 99 |
return(0); /* no sample taken */ |
| 100 |
} |
| 101 |
if (ambacc > FTINY) { |
| 102 |
multcolor(ar.rcoef, hp->acoef); |
| 103 |
scalecolor(ar.rcoef, 1./AVGREFL); |
| 104 |
} |
| 105 |
/* generate hemispherical sample */ |
| 106 |
SDsquare2disk(spt, (i+frandom())/hp->ns, (j+frandom())/hp->ns); |
| 107 |
zd = sqrt(1. - spt[0]*spt[0] - spt[1]*spt[1]); |
| 108 |
for (ii = 3; ii--; ) |
| 109 |
ar.rdir[ii] = spt[0]*hp->ux[ii] + |
| 110 |
spt[1]*hp->uy[ii] + |
| 111 |
zd*hp->rp->ron[ii]; |
| 112 |
checknorm(ar.rdir); |
| 113 |
dimlist[ndims++] = i*hp->ns + j + 90171; |
| 114 |
rayvalue(&ar); /* evaluate ray */ |
| 115 |
ndims--; |
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multcolor(ar.rcol, ar.rcoef); /* apply coefficient */ |
| 117 |
copycolor(ap->v, ar.rcol); |
| 118 |
if (ar.rt > 20.0*maxarad) /* limit vertex distance */ |
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ar.rt = 20.0*maxarad; |
| 120 |
VSUM(ap->p, ar.rorg, ar.rdir, ar.rt); |
| 121 |
return(1); |
| 122 |
} |
| 123 |
|
| 124 |
|
| 125 |
static void |
| 126 |
ambHessian( /* anisotropic radii & pos. gradient */ |
| 127 |
AMBHEMI *hp, |
| 128 |
FVECT uv[2], /* returned */ |
| 129 |
float ra[2], /* returned */ |
| 130 |
float pg[2] /* returned */ |
| 131 |
) |
| 132 |
{ |
| 133 |
if (ra != NULL) { /* compute Hessian-derived radii */ |
| 134 |
} else { /* else copy original tangent axes */ |
| 135 |
VCOPY(uv[0], hp->ux); |
| 136 |
VCOPY(uv[1], hp->uy); |
| 137 |
} |
| 138 |
if (pg == NULL) /* no position gradient requested? */ |
| 139 |
return; |
| 140 |
} |
| 141 |
|
| 142 |
int |
| 143 |
doambient( /* compute ambient component */ |
| 144 |
COLOR rcol, /* input/output color */ |
| 145 |
RAY *r, |
| 146 |
double wt, |
| 147 |
FVECT uv[2], /* returned */ |
| 148 |
float ra[2], /* returned */ |
| 149 |
float pg[2], /* returned */ |
| 150 |
float dg[2] /* returned */ |
| 151 |
) |
| 152 |
{ |
| 153 |
int cnt = 0; |
| 154 |
FVECT my_uv[2]; |
| 155 |
AMBHEMI *hp; |
| 156 |
double d, acol[3]; |
| 157 |
struct s_ambsamp *ap; |
| 158 |
int i, j; |
| 159 |
/* initialize */ |
| 160 |
if ((hp = inithemi(rcol, r, wt)) == NULL) |
| 161 |
return(0); |
| 162 |
if (uv != NULL) |
| 163 |
memset(uv, 0, sizeof(FVECT)*2); |
| 164 |
if (ra != NULL) |
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ra[0] = ra[1] = 0.0; |
| 166 |
if (pg != NULL) |
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pg[0] = pg[1] = 0.0; |
| 168 |
if (dg != NULL) |
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dg[0] = dg[1] = 0.0; |
| 170 |
/* sample the hemisphere */ |
| 171 |
acol[0] = acol[1] = acol[2] = 0.0; |
| 172 |
for (i = hemi.ns; i--; ) |
| 173 |
for (j = hemi.ns; j--; ) |
| 174 |
if (ambsample(hp, i, j)) { |
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ap = &ambsamp(hp,i,j); |
| 176 |
addcolor(acol, ap->v); |
| 177 |
++cnt; |
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} |
| 179 |
if (!cnt) { |
| 180 |
setcolor(rcol, 0.0, 0.0, 0.0); |
| 181 |
free(hp); |
| 182 |
return(0); /* no valid samples */ |
| 183 |
} |
| 184 |
d = 1.0 / cnt; /* final indirect irradiance/PI */ |
| 185 |
acol[0] *= d; acol[1] *= d; acol[2] *= d; |
| 186 |
copycolor(rcol, acol); |
| 187 |
if (cnt < hp->ns*hp->ns || /* incomplete sampling? */ |
| 188 |
(ra == NULL) & (pg == NULL) & (dg == NULL)) { |
| 189 |
free(hp); |
| 190 |
return(-1); /* no radius or gradient calc. */ |
| 191 |
} |
| 192 |
d = 0.01 * bright(rcol); /* add in 1% before Hessian comp. */ |
| 193 |
if (d < FTINY) d = FTINY; |
| 194 |
ap = hp->sa; /* using Y channel from here on... */ |
| 195 |
for (i = hp->ns*hp->ns; i--; ap++) |
| 196 |
colval(ap->v,CIEY) = bright(ap->v) + d; |
| 197 |
|
| 198 |
if (uv == NULL) /* make sure we have axis pointers */ |
| 199 |
uv = my_uv; |
| 200 |
/* compute radii & pos. gradient */ |
| 201 |
ambHessian(hp, uv, ra, pg); |
| 202 |
if (dg != NULL) /* compute direction gradient */ |
| 203 |
ambdirgrad(hp, uv, dg); |
| 204 |
if (ra != NULL) { /* adjust/clamp radii */ |
| 205 |
d = pow(wt, -0.25); |
| 206 |
if ((ra[0] *= d) > maxarad) |
| 207 |
ra[0] = maxarad; |
| 208 |
if ((ra[1] *= d) > 2.0*ra[0]) |
| 209 |
ra[1] = 2.0*ra[0]; |
| 210 |
} |
| 211 |
free(hp); /* clean up and return */ |
| 212 |
return(1); |
| 213 |
} |
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|
| 215 |
|
| 216 |
#else /* ! NEWAMB */ |
| 217 |
|
| 218 |
|
| 219 |
void |
| 220 |
inithemi( /* initialize sampling hemisphere */ |
| 221 |
AMBHEMI *hp, |
| 222 |
COLOR ac, |
| 223 |
RAY *r, |
| 224 |
double wt |
| 225 |
) |
| 226 |
{ |
| 227 |
double d; |
| 228 |
int i; |
| 229 |
/* set number of divisions */ |
| 230 |
if (ambacc <= FTINY && |
| 231 |
wt > (d = 0.8*intens(ac)*r->rweight/(ambdiv*minweight))) |
| 232 |
wt = d; /* avoid ray termination */ |
| 233 |
hp->nt = sqrt(ambdiv * wt / PI) + 0.5; |
| 234 |
i = ambacc > FTINY ? 3 : 1; /* minimum number of samples */ |
| 235 |
if (hp->nt < i) |
| 236 |
hp->nt = i; |
| 237 |
hp->np = PI * hp->nt + 0.5; |
| 238 |
/* set number of super-samples */ |
| 239 |
hp->ns = ambssamp * wt + 0.5; |
| 240 |
/* assign coefficient */ |
| 241 |
copycolor(hp->acoef, ac); |
| 242 |
d = 1.0/(hp->nt*hp->np); |
| 243 |
scalecolor(hp->acoef, d); |
| 244 |
/* make axes */ |
| 245 |
VCOPY(hp->uz, r->ron); |
| 246 |
hp->uy[0] = hp->uy[1] = hp->uy[2] = 0.0; |
| 247 |
for (i = 0; i < 3; i++) |
| 248 |
if (hp->uz[i] < 0.6 && hp->uz[i] > -0.6) |
| 249 |
break; |
| 250 |
if (i >= 3) |
| 251 |
error(CONSISTENCY, "bad ray direction in inithemi"); |
| 252 |
hp->uy[i] = 1.0; |
| 253 |
fcross(hp->ux, hp->uy, hp->uz); |
| 254 |
normalize(hp->ux); |
| 255 |
fcross(hp->uy, hp->uz, hp->ux); |
| 256 |
} |
| 257 |
|
| 258 |
|
| 259 |
int |
| 260 |
divsample( /* sample a division */ |
| 261 |
AMBSAMP *dp, |
| 262 |
AMBHEMI *h, |
| 263 |
RAY *r |
| 264 |
) |
| 265 |
{ |
| 266 |
RAY ar; |
| 267 |
int hlist[3]; |
| 268 |
double spt[2]; |
| 269 |
double xd, yd, zd; |
| 270 |
double b2; |
| 271 |
double phi; |
| 272 |
int i; |
| 273 |
/* ambient coefficient for weight */ |
| 274 |
if (ambacc > FTINY) |
| 275 |
setcolor(ar.rcoef, AVGREFL, AVGREFL, AVGREFL); |
| 276 |
else |
| 277 |
copycolor(ar.rcoef, h->acoef); |
| 278 |
if (rayorigin(&ar, AMBIENT, r, ar.rcoef) < 0) |
| 279 |
return(-1); |
| 280 |
if (ambacc > FTINY) { |
| 281 |
multcolor(ar.rcoef, h->acoef); |
| 282 |
scalecolor(ar.rcoef, 1./AVGREFL); |
| 283 |
} |
| 284 |
hlist[0] = r->rno; |
| 285 |
hlist[1] = dp->t; |
| 286 |
hlist[2] = dp->p; |
| 287 |
multisamp(spt, 2, urand(ilhash(hlist,3)+dp->n)); |
| 288 |
zd = sqrt((dp->t + spt[0])/h->nt); |
| 289 |
phi = 2.0*PI * (dp->p + spt[1])/h->np; |
| 290 |
xd = tcos(phi) * zd; |
| 291 |
yd = tsin(phi) * zd; |
| 292 |
zd = sqrt(1.0 - zd*zd); |
| 293 |
for (i = 0; i < 3; i++) |
| 294 |
ar.rdir[i] = xd*h->ux[i] + |
| 295 |
yd*h->uy[i] + |
| 296 |
zd*h->uz[i]; |
| 297 |
checknorm(ar.rdir); |
| 298 |
dimlist[ndims++] = dp->t*h->np + dp->p + 90171; |
| 299 |
rayvalue(&ar); |
| 300 |
ndims--; |
| 301 |
multcolor(ar.rcol, ar.rcoef); /* apply coefficient */ |
| 302 |
addcolor(dp->v, ar.rcol); |
| 303 |
/* use rt to improve gradient calc */ |
| 304 |
if (ar.rt > FTINY && ar.rt < FHUGE) |
| 305 |
dp->r += 1.0/ar.rt; |
| 306 |
/* (re)initialize error */ |
| 307 |
if (dp->n++) { |
| 308 |
b2 = bright(dp->v)/dp->n - bright(ar.rcol); |
| 309 |
b2 = b2*b2 + dp->k*((dp->n-1)*(dp->n-1)); |
| 310 |
dp->k = b2/(dp->n*dp->n); |
| 311 |
} else |
| 312 |
dp->k = 0.0; |
| 313 |
return(0); |
| 314 |
} |
| 315 |
|
| 316 |
|
| 317 |
static int |
| 318 |
ambcmp( /* decreasing order */ |
| 319 |
const void *p1, |
| 320 |
const void *p2 |
| 321 |
) |
| 322 |
{ |
| 323 |
const AMBSAMP *d1 = (const AMBSAMP *)p1; |
| 324 |
const AMBSAMP *d2 = (const AMBSAMP *)p2; |
| 325 |
|
| 326 |
if (d1->k < d2->k) |
| 327 |
return(1); |
| 328 |
if (d1->k > d2->k) |
| 329 |
return(-1); |
| 330 |
return(0); |
| 331 |
} |
| 332 |
|
| 333 |
|
| 334 |
static int |
| 335 |
ambnorm( /* standard order */ |
| 336 |
const void *p1, |
| 337 |
const void *p2 |
| 338 |
) |
| 339 |
{ |
| 340 |
const AMBSAMP *d1 = (const AMBSAMP *)p1; |
| 341 |
const AMBSAMP *d2 = (const AMBSAMP *)p2; |
| 342 |
int c; |
| 343 |
|
| 344 |
if ( (c = d1->t - d2->t) ) |
| 345 |
return(c); |
| 346 |
return(d1->p - d2->p); |
| 347 |
} |
| 348 |
|
| 349 |
|
| 350 |
double |
| 351 |
doambient( /* compute ambient component */ |
| 352 |
COLOR rcol, |
| 353 |
RAY *r, |
| 354 |
double wt, |
| 355 |
FVECT pg, |
| 356 |
FVECT dg |
| 357 |
) |
| 358 |
{ |
| 359 |
double b, d=0; |
| 360 |
AMBHEMI hemi; |
| 361 |
AMBSAMP *div; |
| 362 |
AMBSAMP dnew; |
| 363 |
double acol[3]; |
| 364 |
AMBSAMP *dp; |
| 365 |
double arad; |
| 366 |
int divcnt; |
| 367 |
int i, j; |
| 368 |
/* initialize hemisphere */ |
| 369 |
inithemi(&hemi, rcol, r, wt); |
| 370 |
divcnt = hemi.nt * hemi.np; |
| 371 |
/* initialize */ |
| 372 |
if (pg != NULL) |
| 373 |
pg[0] = pg[1] = pg[2] = 0.0; |
| 374 |
if (dg != NULL) |
| 375 |
dg[0] = dg[1] = dg[2] = 0.0; |
| 376 |
setcolor(rcol, 0.0, 0.0, 0.0); |
| 377 |
if (divcnt == 0) |
| 378 |
return(0.0); |
| 379 |
/* allocate super-samples */ |
| 380 |
if (hemi.ns > 0 || pg != NULL || dg != NULL) { |
| 381 |
div = (AMBSAMP *)malloc(divcnt*sizeof(AMBSAMP)); |
| 382 |
if (div == NULL) |
| 383 |
error(SYSTEM, "out of memory in doambient"); |
| 384 |
} else |
| 385 |
div = NULL; |
| 386 |
/* sample the divisions */ |
| 387 |
arad = 0.0; |
| 388 |
acol[0] = acol[1] = acol[2] = 0.0; |
| 389 |
if ((dp = div) == NULL) |
| 390 |
dp = &dnew; |
| 391 |
divcnt = 0; |
| 392 |
for (i = 0; i < hemi.nt; i++) |
| 393 |
for (j = 0; j < hemi.np; j++) { |
| 394 |
dp->t = i; dp->p = j; |
| 395 |
setcolor(dp->v, 0.0, 0.0, 0.0); |
| 396 |
dp->r = 0.0; |
| 397 |
dp->n = 0; |
| 398 |
if (divsample(dp, &hemi, r) < 0) { |
| 399 |
if (div != NULL) |
| 400 |
dp++; |
| 401 |
continue; |
| 402 |
} |
| 403 |
arad += dp->r; |
| 404 |
divcnt++; |
| 405 |
if (div != NULL) |
| 406 |
dp++; |
| 407 |
else |
| 408 |
addcolor(acol, dp->v); |
| 409 |
} |
| 410 |
if (!divcnt) { |
| 411 |
if (div != NULL) |
| 412 |
free((void *)div); |
| 413 |
return(0.0); /* no samples taken */ |
| 414 |
} |
| 415 |
if (divcnt < hemi.nt*hemi.np) { |
| 416 |
pg = dg = NULL; /* incomplete sampling */ |
| 417 |
hemi.ns = 0; |
| 418 |
} else if (arad > FTINY && divcnt/arad < minarad) { |
| 419 |
hemi.ns = 0; /* close enough */ |
| 420 |
} else if (hemi.ns > 0) { /* else perform super-sampling? */ |
| 421 |
comperrs(div, &hemi); /* compute errors */ |
| 422 |
qsort(div, divcnt, sizeof(AMBSAMP), ambcmp); /* sort divs */ |
| 423 |
/* super-sample */ |
| 424 |
for (i = hemi.ns; i > 0; i--) { |
| 425 |
dnew = *div; |
| 426 |
if (divsample(&dnew, &hemi, r) < 0) { |
| 427 |
dp++; |
| 428 |
continue; |
| 429 |
} |
| 430 |
dp = div; /* reinsert */ |
| 431 |
j = divcnt < i ? divcnt : i; |
| 432 |
while (--j > 0 && dnew.k < dp[1].k) { |
| 433 |
*dp = *(dp+1); |
| 434 |
dp++; |
| 435 |
} |
| 436 |
*dp = dnew; |
| 437 |
} |
| 438 |
if (pg != NULL || dg != NULL) /* restore order */ |
| 439 |
qsort(div, divcnt, sizeof(AMBSAMP), ambnorm); |
| 440 |
} |
| 441 |
/* compute returned values */ |
| 442 |
if (div != NULL) { |
| 443 |
arad = 0.0; /* note: divcnt may be < nt*np */ |
| 444 |
for (i = hemi.nt*hemi.np, dp = div; i-- > 0; dp++) { |
| 445 |
arad += dp->r; |
| 446 |
if (dp->n > 1) { |
| 447 |
b = 1.0/dp->n; |
| 448 |
scalecolor(dp->v, b); |
| 449 |
dp->r *= b; |
| 450 |
dp->n = 1; |
| 451 |
} |
| 452 |
addcolor(acol, dp->v); |
| 453 |
} |
| 454 |
b = bright(acol); |
| 455 |
if (b > FTINY) { |
| 456 |
b = 1.0/b; /* compute & normalize gradient(s) */ |
| 457 |
if (pg != NULL) { |
| 458 |
posgradient(pg, div, &hemi); |
| 459 |
for (i = 0; i < 3; i++) |
| 460 |
pg[i] *= b; |
| 461 |
} |
| 462 |
if (dg != NULL) { |
| 463 |
dirgradient(dg, div, &hemi); |
| 464 |
for (i = 0; i < 3; i++) |
| 465 |
dg[i] *= b; |
| 466 |
} |
| 467 |
} |
| 468 |
free((void *)div); |
| 469 |
} |
| 470 |
copycolor(rcol, acol); |
| 471 |
if (arad <= FTINY) |
| 472 |
arad = maxarad; |
| 473 |
else |
| 474 |
arad = (divcnt+hemi.ns)/arad; |
| 475 |
if (pg != NULL) { /* reduce radius if gradient large */ |
| 476 |
d = DOT(pg,pg); |
| 477 |
if (d*arad*arad > 1.0) |
| 478 |
arad = 1.0/sqrt(d); |
| 479 |
} |
| 480 |
if (arad < minarad) { |
| 481 |
arad = minarad; |
| 482 |
if (pg != NULL && d*arad*arad > 1.0) { /* cap gradient */ |
| 483 |
d = 1.0/arad/sqrt(d); |
| 484 |
for (i = 0; i < 3; i++) |
| 485 |
pg[i] *= d; |
| 486 |
} |
| 487 |
} |
| 488 |
if ((arad /= sqrt(wt)) > maxarad) |
| 489 |
arad = maxarad; |
| 490 |
return(arad); |
| 491 |
} |
| 492 |
|
| 493 |
|
| 494 |
void |
| 495 |
comperrs( /* compute initial error estimates */ |
| 496 |
AMBSAMP *da, /* assumes standard ordering */ |
| 497 |
AMBHEMI *hp |
| 498 |
) |
| 499 |
{ |
| 500 |
double b, b2; |
| 501 |
int i, j; |
| 502 |
AMBSAMP *dp; |
| 503 |
/* sum differences from neighbors */ |
| 504 |
dp = da; |
| 505 |
for (i = 0; i < hp->nt; i++) |
| 506 |
for (j = 0; j < hp->np; j++) { |
| 507 |
#ifdef DEBUG |
| 508 |
if (dp->t != i || dp->p != j) |
| 509 |
error(CONSISTENCY, |
| 510 |
"division order in comperrs"); |
| 511 |
#endif |
| 512 |
b = bright(dp[0].v); |
| 513 |
if (i > 0) { /* from above */ |
| 514 |
b2 = bright(dp[-hp->np].v) - b; |
| 515 |
b2 *= b2 * 0.25; |
| 516 |
dp[0].k += b2; |
| 517 |
dp[-hp->np].k += b2; |
| 518 |
} |
| 519 |
if (j > 0) { /* from behind */ |
| 520 |
b2 = bright(dp[-1].v) - b; |
| 521 |
b2 *= b2 * 0.25; |
| 522 |
dp[0].k += b2; |
| 523 |
dp[-1].k += b2; |
| 524 |
} else { /* around */ |
| 525 |
b2 = bright(dp[hp->np-1].v) - b; |
| 526 |
b2 *= b2 * 0.25; |
| 527 |
dp[0].k += b2; |
| 528 |
dp[hp->np-1].k += b2; |
| 529 |
} |
| 530 |
dp++; |
| 531 |
} |
| 532 |
/* divide by number of neighbors */ |
| 533 |
dp = da; |
| 534 |
for (j = 0; j < hp->np; j++) /* top row */ |
| 535 |
(dp++)->k *= 1.0/3.0; |
| 536 |
if (hp->nt < 2) |
| 537 |
return; |
| 538 |
for (i = 1; i < hp->nt-1; i++) /* central region */ |
| 539 |
for (j = 0; j < hp->np; j++) |
| 540 |
(dp++)->k *= 0.25; |
| 541 |
for (j = 0; j < hp->np; j++) /* bottom row */ |
| 542 |
(dp++)->k *= 1.0/3.0; |
| 543 |
} |
| 544 |
|
| 545 |
|
| 546 |
void |
| 547 |
posgradient( /* compute position gradient */ |
| 548 |
FVECT gv, |
| 549 |
AMBSAMP *da, /* assumes standard ordering */ |
| 550 |
AMBHEMI *hp |
| 551 |
) |
| 552 |
{ |
| 553 |
int i, j; |
| 554 |
double nextsine, lastsine, b, d; |
| 555 |
double mag0, mag1; |
| 556 |
double phi, cosp, sinp, xd, yd; |
| 557 |
AMBSAMP *dp; |
| 558 |
|
| 559 |
xd = yd = 0.0; |
| 560 |
for (j = 0; j < hp->np; j++) { |
| 561 |
dp = da + j; |
| 562 |
mag0 = mag1 = 0.0; |
| 563 |
lastsine = 0.0; |
| 564 |
for (i = 0; i < hp->nt; i++) { |
| 565 |
#ifdef DEBUG |
| 566 |
if (dp->t != i || dp->p != j) |
| 567 |
error(CONSISTENCY, |
| 568 |
"division order in posgradient"); |
| 569 |
#endif |
| 570 |
b = bright(dp->v); |
| 571 |
if (i > 0) { |
| 572 |
d = dp[-hp->np].r; |
| 573 |
if (dp[0].r > d) d = dp[0].r; |
| 574 |
/* sin(t)*cos(t)^2 */ |
| 575 |
d *= lastsine * (1.0 - (double)i/hp->nt); |
| 576 |
mag0 += d*(b - bright(dp[-hp->np].v)); |
| 577 |
} |
| 578 |
nextsine = sqrt((double)(i+1)/hp->nt); |
| 579 |
if (j > 0) { |
| 580 |
d = dp[-1].r; |
| 581 |
if (dp[0].r > d) d = dp[0].r; |
| 582 |
mag1 += d * (nextsine - lastsine) * |
| 583 |
(b - bright(dp[-1].v)); |
| 584 |
} else { |
| 585 |
d = dp[hp->np-1].r; |
| 586 |
if (dp[0].r > d) d = dp[0].r; |
| 587 |
mag1 += d * (nextsine - lastsine) * |
| 588 |
(b - bright(dp[hp->np-1].v)); |
| 589 |
} |
| 590 |
dp += hp->np; |
| 591 |
lastsine = nextsine; |
| 592 |
} |
| 593 |
mag0 *= 2.0*PI / hp->np; |
| 594 |
phi = 2.0*PI * (double)j/hp->np; |
| 595 |
cosp = tcos(phi); sinp = tsin(phi); |
| 596 |
xd += mag0*cosp - mag1*sinp; |
| 597 |
yd += mag0*sinp + mag1*cosp; |
| 598 |
} |
| 599 |
for (i = 0; i < 3; i++) |
| 600 |
gv[i] = (xd*hp->ux[i] + yd*hp->uy[i])*(hp->nt*hp->np)/PI; |
| 601 |
} |
| 602 |
|
| 603 |
|
| 604 |
void |
| 605 |
dirgradient( /* compute direction gradient */ |
| 606 |
FVECT gv, |
| 607 |
AMBSAMP *da, /* assumes standard ordering */ |
| 608 |
AMBHEMI *hp |
| 609 |
) |
| 610 |
{ |
| 611 |
int i, j; |
| 612 |
double mag; |
| 613 |
double phi, xd, yd; |
| 614 |
AMBSAMP *dp; |
| 615 |
|
| 616 |
xd = yd = 0.0; |
| 617 |
for (j = 0; j < hp->np; j++) { |
| 618 |
dp = da + j; |
| 619 |
mag = 0.0; |
| 620 |
for (i = 0; i < hp->nt; i++) { |
| 621 |
#ifdef DEBUG |
| 622 |
if (dp->t != i || dp->p != j) |
| 623 |
error(CONSISTENCY, |
| 624 |
"division order in dirgradient"); |
| 625 |
#endif |
| 626 |
/* tan(t) */ |
| 627 |
mag += bright(dp->v)/sqrt(hp->nt/(i+.5) - 1.0); |
| 628 |
dp += hp->np; |
| 629 |
} |
| 630 |
phi = 2.0*PI * (j+.5)/hp->np + PI/2.0; |
| 631 |
xd += mag * tcos(phi); |
| 632 |
yd += mag * tsin(phi); |
| 633 |
} |
| 634 |
for (i = 0; i < 3; i++) |
| 635 |
gv[i] = xd*hp->ux[i] + yd*hp->uy[i]; |
| 636 |
} |
| 637 |
|
| 638 |
#endif /* ! NEWAMB */ |
