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; |
58 |
|
RAY *r; |
59 |
|
{ |
60 |
|
RAY ar; |
61 |
< |
int hlist[4]; |
61 |
> |
int hlist[3]; |
62 |
> |
double spt[2]; |
63 |
|
double xd, yd, zd; |
64 |
|
double b2; |
65 |
|
double phi; |
66 |
|
register int i; |
67 |
|
|
68 |
< |
if (rayorigin(&ar, r, AMBIENT, 0.5) < 0) |
68 |
> |
if (rayorigin(&ar, r, AMBIENT, AVGREFL) < 0) |
69 |
|
return(-1); |
70 |
|
hlist[0] = r->rno; |
71 |
|
hlist[1] = dp->t; |
72 |
|
hlist[2] = dp->p; |
73 |
< |
hlist[3] = 0; |
74 |
< |
zd = sqrt((dp->t+urand(ilhash(hlist,4)+dp->n))/h->nt); |
75 |
< |
hlist[3] = 1; |
77 |
< |
phi = 2.0*PI * (dp->p+urand(ilhash(hlist,4)+dp->n))/h->np; |
73 |
> |
multisamp(spt, 2, urand(ilhash(hlist,3)+dp->n)); |
74 |
> |
zd = sqrt((dp->t + spt[0])/h->nt); |
75 |
> |
phi = 2.0*PI * (dp->p + spt[1])/h->np; |
76 |
|
xd = cos(phi) * zd; |
77 |
|
yd = sin(phi) * zd; |
78 |
|
zd = sqrt(1.0 - zd*zd); |
84 |
|
rayvalue(&ar); |
85 |
|
ndims--; |
86 |
|
addcolor(dp->v, ar.rcol); |
87 |
< |
if (ar.rt < FHUGE) |
87 |
> |
if (ar.rt > FTINY && ar.rt < FHUGE) |
88 |
|
dp->r += 1.0/ar.rt; |
89 |
|
/* (re)initialize error */ |
90 |
|
if (dp->n++) { |
98 |
|
|
99 |
|
|
100 |
|
double |
101 |
< |
doambient(acol, r, pg, dg) /* compute ambient component */ |
101 |
> |
doambient(acol, r, wt, pg, dg) /* compute ambient component */ |
102 |
|
COLOR acol; |
103 |
|
RAY *r; |
104 |
+ |
double wt; |
105 |
|
FVECT pg, dg; |
106 |
|
{ |
107 |
|
double b, d; |
115 |
|
/* initialize color */ |
116 |
|
setcolor(acol, 0.0, 0.0, 0.0); |
117 |
|
/* initialize hemisphere */ |
118 |
< |
inithemi(&hemi, r); |
118 |
> |
inithemi(&hemi, r, wt); |
119 |
|
ndivs = hemi.nt * hemi.np; |
120 |
|
if (ndivs == 0) |
121 |
|
return(0.0); |
122 |
|
/* set number of super-samples */ |
123 |
< |
ns = ambssamp * r->rweight + 0.5; |
123 |
> |
ns = ambssamp * wt + 0.5; |
124 |
|
if (ns > 0 || pg != NULL || dg != NULL) { |
125 |
|
div = (AMBSAMP *)malloc(ndivs*sizeof(AMBSAMP)); |
126 |
|
if (div == NULL) |
146 |
|
arad += dp->r; |
147 |
|
} |
148 |
|
} |
149 |
< |
if (ns > 0) { /* perform super-sampling */ |
149 |
> |
if (ns > 0 && arad > FTINY && ndivs/arad < minarad) |
150 |
> |
ns = 0; /* close enough */ |
151 |
> |
else if (ns > 0) { /* else perform super-sampling */ |
152 |
|
comperrs(div, &hemi); /* compute errors */ |
153 |
|
qsort(div, ndivs, sizeof(AMBSAMP), ambcmp); /* sort divs */ |
154 |
|
/* super-sample */ |
206 |
|
b = 1.0/ndivs; |
207 |
|
scalecolor(acol, b); |
208 |
|
if (arad <= FTINY) |
209 |
< |
arad = FHUGE; |
209 |
> |
arad = maxarad; |
210 |
|
else |
211 |
|
arad = (ndivs+ns)/arad; |
212 |
< |
if (arad > maxarad) |
213 |
< |
arad = maxarad; |
214 |
< |
else if (arad < minarad) |
212 |
> |
if (pg != NULL) { /* reduce radius if gradient large */ |
213 |
> |
d = DOT(pg,pg); |
214 |
> |
if (d*arad*arad > 1.0) |
215 |
> |
arad = 1.0/sqrt(d); |
216 |
> |
} |
217 |
> |
if (arad < minarad) { |
218 |
|
arad = minarad; |
219 |
< |
arad /= sqrt(r->rweight); |
220 |
< |
if (pg != NULL) { /* clip pos. gradient if too large */ |
217 |
< |
d = 4.0*DOT(pg,pg)*arad*arad; |
218 |
< |
if (d > 1.0) { |
219 |
< |
d = 1.0/sqrt(d); |
219 |
> |
if (pg != NULL && d*arad*arad > 1.0) { /* cap gradient */ |
220 |
> |
d = 1.0/arad/sqrt(d); |
221 |
|
for (i = 0; i < 3; i++) |
222 |
|
pg[i] *= d; |
223 |
|
} |
224 |
|
} |
225 |
+ |
if ((arad /= sqrt(wt)) > maxarad) |
226 |
+ |
arad = maxarad; |
227 |
|
return(arad); |
228 |
|
oopsy: |
229 |
|
if (div != NULL) |
232 |
|
} |
233 |
|
|
234 |
|
|
235 |
< |
inithemi(hp, r) /* initialize sampling hemisphere */ |
235 |
> |
inithemi(hp, r, wt) /* initialize sampling hemisphere */ |
236 |
|
register AMBHEMI *hp; |
237 |
|
RAY *r; |
238 |
+ |
double wt; |
239 |
|
{ |
240 |
|
register int i; |
241 |
|
/* set number of divisions */ |
242 |
< |
hp->nt = sqrt(ambdiv * r->rweight * 0.5) + 0.5; |
243 |
< |
hp->np = 2 * hp->nt; |
242 |
> |
if (wt < (.25*PI)/ambdiv+FTINY) { |
243 |
> |
hp->nt = hp->np = 0; |
244 |
> |
return; /* zero samples */ |
245 |
> |
} |
246 |
> |
hp->nt = sqrt(ambdiv * wt / PI) + 0.5; |
247 |
> |
hp->np = PI * hp->nt + 0.5; |
248 |
|
/* make axes */ |
249 |
|
VCOPY(hp->uz, r->ron); |
250 |
|
hp->uy[0] = hp->uy[1] = hp->uy[2] = 0.0; |
313 |
|
posgradient(gv, da, hp) /* compute position gradient */ |
314 |
|
FVECT gv; |
315 |
|
AMBSAMP *da; /* assumes standard ordering */ |
316 |
< |
AMBHEMI *hp; |
316 |
> |
register AMBHEMI *hp; |
317 |
|
{ |
318 |
|
register int i, j; |
319 |
< |
double b, d; |
319 |
> |
double nextsine, lastsine, b, d; |
320 |
|
double mag0, mag1; |
321 |
|
double phi, cosp, sinp, xd, yd; |
322 |
|
register AMBSAMP *dp; |
325 |
|
for (j = 0; j < hp->np; j++) { |
326 |
|
dp = da + j; |
327 |
|
mag0 = mag1 = 0.0; |
328 |
+ |
lastsine = 0.0; |
329 |
|
for (i = 0; i < hp->nt; i++) { |
330 |
|
#ifdef DEBUG |
331 |
|
if (dp->t != i || dp->p != j) |
336 |
|
if (i > 0) { |
337 |
|
d = dp[-hp->np].r; |
338 |
|
if (dp[0].r > d) d = dp[0].r; |
339 |
< |
d *= 1.0 - sqrt((double)i/hp->nt); |
339 |
> |
/* sin(t)*cos(t)^2 */ |
340 |
> |
d *= lastsine * (1.0 - (double)i/hp->nt); |
341 |
|
mag0 += d*(b - bright(dp[-hp->np].v)); |
342 |
|
} |
343 |
+ |
nextsine = sqrt((double)(i+1)/hp->nt); |
344 |
|
if (j > 0) { |
345 |
|
d = dp[-1].r; |
346 |
|
if (dp[0].r > d) d = dp[0].r; |
347 |
< |
mag1 += d*(b - bright(dp[-1].v)); |
347 |
> |
mag1 += d * (nextsine - lastsine) * |
348 |
> |
(b - bright(dp[-1].v)); |
349 |
|
} else { |
350 |
|
d = dp[hp->np-1].r; |
351 |
|
if (dp[0].r > d) d = dp[0].r; |
352 |
< |
mag1 += d*(b - bright(dp[hp->np-1].v)); |
352 |
> |
mag1 += d * (nextsine - lastsine) * |
353 |
> |
(b - bright(dp[hp->np-1].v)); |
354 |
|
} |
355 |
|
dp += hp->np; |
356 |
+ |
lastsine = nextsine; |
357 |
|
} |
358 |
< |
if (hp->nt > 1) { |
345 |
< |
mag0 /= (double)hp->np; |
346 |
< |
mag1 /= (double)hp->nt; |
347 |
< |
} |
358 |
> |
mag0 *= 2.0*PI / hp->np; |
359 |
|
phi = 2.0*PI * (double)j/hp->np; |
360 |
|
cosp = cos(phi); sinp = sin(phi); |
361 |
|
xd += mag0*cosp - mag1*sinp; |
369 |
|
dirgradient(gv, da, hp) /* compute direction gradient */ |
370 |
|
FVECT gv; |
371 |
|
AMBSAMP *da; /* assumes standard ordering */ |
372 |
< |
AMBHEMI *hp; |
372 |
> |
register AMBHEMI *hp; |
373 |
|
{ |
374 |
|
register int i, j; |
375 |
|
double mag; |
386 |
|
error(CONSISTENCY, |
387 |
|
"division order in dirgradient"); |
388 |
|
#endif |
389 |
< |
mag += sqrt((i+.5)/hp->nt)*bright(dp->v); |
389 |
> |
/* tan(t) */ |
390 |
> |
mag += bright(dp->v)/sqrt(hp->nt/(i+.5) - 1.0); |
391 |
|
dp += hp->np; |
392 |
|
} |
393 |
|
phi = 2.0*PI * (j+.5)/hp->np + PI/2.0; |
395 |
|
yd += mag * sin(phi); |
396 |
|
} |
397 |
|
for (i = 0; i < 3; i++) |
398 |
< |
gv[i] = (xd*hp->ux[i] + yd*hp->uy[i])*PI/(hp->nt*hp->np); |
398 |
> |
gv[i] = (xd*hp->ux[i] + yd*hp->uy[i])/(hp->nt*hp->np); |
399 |
|
} |