| 27 |
|
short nt, np; /* number of theta and phi directions */ |
| 28 |
|
} AMBHEMI; /* ambient sample hemisphere */ |
| 29 |
|
|
| 30 |
– |
extern double sin(), cos(), sqrt(); |
| 30 |
|
|
| 32 |
– |
|
| 31 |
|
static int |
| 32 |
|
ambcmp(d1, d2) /* decreasing order */ |
| 33 |
|
AMBSAMP *d1, *d2; |
| 204 |
|
b = 1.0/ndivs; |
| 205 |
|
scalecolor(acol, b); |
| 206 |
|
if (arad <= FTINY) |
| 207 |
< |
arad = FHUGE; |
| 207 |
> |
arad = maxarad; |
| 208 |
|
else |
| 209 |
|
arad = (ndivs+ns)/arad; |
| 210 |
|
if (pg != NULL) { /* reduce radius if gradient large */ |
| 212 |
|
if (d*arad*arad > 1.0) |
| 213 |
|
arad = 1.0/sqrt(d); |
| 214 |
|
} |
| 215 |
< |
if (arad > maxarad) |
| 218 |
< |
arad = maxarad; |
| 219 |
< |
else if (arad < minarad) |
| 215 |
> |
if (arad < minarad) { |
| 216 |
|
arad = minarad; |
| 217 |
< |
return(arad/sqrt(wt)); |
| 217 |
> |
if (pg != NULL && d*arad*arad > 1.0) { /* cap gradient */ |
| 218 |
> |
d = 1.0/arad/sqrt(d); |
| 219 |
> |
for (i = 0; i < 3; i++) |
| 220 |
> |
pg[i] *= d; |
| 221 |
> |
} |
| 222 |
> |
} |
| 223 |
> |
if ((arad /= sqrt(wt)) > maxarad) |
| 224 |
> |
arad = maxarad; |
| 225 |
> |
return(arad); |
| 226 |
|
oopsy: |
| 227 |
|
if (div != NULL) |
| 228 |
|
free((char *)div); |
| 311 |
|
posgradient(gv, da, hp) /* compute position gradient */ |
| 312 |
|
FVECT gv; |
| 313 |
|
AMBSAMP *da; /* assumes standard ordering */ |
| 314 |
< |
AMBHEMI *hp; |
| 314 |
> |
register AMBHEMI *hp; |
| 315 |
|
{ |
| 316 |
|
register int i, j; |
| 317 |
< |
double b, d; |
| 317 |
> |
double nextsine, lastsine, b, d; |
| 318 |
|
double mag0, mag1; |
| 319 |
|
double phi, cosp, sinp, xd, yd; |
| 320 |
|
register AMBSAMP *dp; |
| 323 |
|
for (j = 0; j < hp->np; j++) { |
| 324 |
|
dp = da + j; |
| 325 |
|
mag0 = mag1 = 0.0; |
| 326 |
+ |
lastsine = 0.0; |
| 327 |
|
for (i = 0; i < hp->nt; i++) { |
| 328 |
|
#ifdef DEBUG |
| 329 |
|
if (dp->t != i || dp->p != j) |
| 334 |
|
if (i > 0) { |
| 335 |
|
d = dp[-hp->np].r; |
| 336 |
|
if (dp[0].r > d) d = dp[0].r; |
| 337 |
< |
d *= 1.0 - (double)i/hp->nt; /* cos(t)^2 */ |
| 337 |
> |
/* sin(t)*cos(t)^2 */ |
| 338 |
> |
d *= lastsine * (1.0 - (double)i/hp->nt); |
| 339 |
|
mag0 += d*(b - bright(dp[-hp->np].v)); |
| 340 |
|
} |
| 341 |
+ |
nextsine = sqrt((double)(i+1)/hp->nt); |
| 342 |
|
if (j > 0) { |
| 343 |
|
d = dp[-1].r; |
| 344 |
|
if (dp[0].r > d) d = dp[0].r; |
| 345 |
< |
mag1 += d*(b - bright(dp[-1].v)); |
| 345 |
> |
mag1 += d * (nextsine - lastsine) * |
| 346 |
> |
(b - bright(dp[-1].v)); |
| 347 |
|
} else { |
| 348 |
|
d = dp[hp->np-1].r; |
| 349 |
|
if (dp[0].r > d) d = dp[0].r; |
| 350 |
< |
mag1 += d*(b - bright(dp[hp->np-1].v)); |
| 350 |
> |
mag1 += d * (nextsine - lastsine) * |
| 351 |
> |
(b - bright(dp[hp->np-1].v)); |
| 352 |
|
} |
| 353 |
|
dp += hp->np; |
| 354 |
+ |
lastsine = nextsine; |
| 355 |
|
} |
| 356 |
< |
if (hp->nt > 1) { |
| 347 |
< |
mag0 /= (double)hp->np; |
| 348 |
< |
mag1 /= (double)hp->nt; |
| 349 |
< |
} |
| 356 |
> |
mag0 *= 2.0*PI / hp->np; |
| 357 |
|
phi = 2.0*PI * (double)j/hp->np; |
| 358 |
|
cosp = cos(phi); sinp = sin(phi); |
| 359 |
|
xd += mag0*cosp - mag1*sinp; |
| 367 |
|
dirgradient(gv, da, hp) /* compute direction gradient */ |
| 368 |
|
FVECT gv; |
| 369 |
|
AMBSAMP *da; /* assumes standard ordering */ |
| 370 |
< |
AMBHEMI *hp; |
| 370 |
> |
register AMBHEMI *hp; |
| 371 |
|
{ |
| 372 |
|
register int i, j; |
| 373 |
|
double mag; |
| 384 |
|
error(CONSISTENCY, |
| 385 |
|
"division order in dirgradient"); |
| 386 |
|
#endif |
| 387 |
< |
mag += sqrt((i+.5)/hp->nt)*bright(dp->v); /* sin(t) */ |
| 387 |
> |
/* tan(t) */ |
| 388 |
> |
mag += bright(dp->v)/sqrt(hp->nt/(i+.5) - 1.0); |
| 389 |
|
dp += hp->np; |
| 390 |
|
} |
| 391 |
|
phi = 2.0*PI * (j+.5)/hp->np + PI/2.0; |
| 393 |
|
yd += mag * sin(phi); |
| 394 |
|
} |
| 395 |
|
for (i = 0; i < 3; i++) |
| 396 |
< |
gv[i] = (xd*hp->ux[i] + yd*hp->uy[i])*PI/(hp->nt*hp->np); |
| 396 |
> |
gv[i] = (xd*hp->ux[i] + yd*hp->uy[i])/(hp->nt*hp->np); |
| 397 |
|
} |
