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; |
205 |
|
scalecolor(acol, b); |
206 |
|
if (arad <= FTINY) |
207 |
|
arad = maxarad; |
208 |
< |
else { |
208 |
> |
else |
209 |
|
arad = (ndivs+ns)/arad; |
212 |
– |
if (arad > maxarad) |
213 |
– |
arad = maxarad; |
214 |
– |
} |
210 |
|
if (pg != NULL) { /* reduce radius if gradient large */ |
211 |
|
d = DOT(pg,pg); |
212 |
|
if (d*arad*arad > 1.0) |
220 |
|
pg[i] *= d; |
221 |
|
} |
222 |
|
} |
223 |
< |
return(arad/sqrt(wt)); |
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) { |
354 |
< |
mag0 /= (double)hp->np; |
355 |
< |
mag1 /= (double)hp->nt; |
356 |
< |
} |
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 |
|
} |