| 1 |
/* Copyright (c) 1986 Regents of the University of California */ |
| 2 |
|
| 3 |
#ifndef lint |
| 4 |
static char SCCSid[] = "$SunId$ LBL"; |
| 5 |
#endif |
| 6 |
|
| 7 |
/* |
| 8 |
* ambient.c - routines dealing with ambient (inter-reflected) component. |
| 9 |
* |
| 10 |
* The macro AMBFLUSH (if defined) is the number of ambient values |
| 11 |
* to wait before flushing to the ambient file. |
| 12 |
* |
| 13 |
* 5/9/86 |
| 14 |
*/ |
| 15 |
|
| 16 |
#include "ray.h" |
| 17 |
|
| 18 |
#include "octree.h" |
| 19 |
|
| 20 |
#include "random.h" |
| 21 |
|
| 22 |
#define OCTSCALE 0.5 /* ceil((valid rad.)/(cube size)) */ |
| 23 |
|
| 24 |
#define WDONE 4 /* stop if wsum/wmin is at or above */ |
| 25 |
|
| 26 |
extern CUBE thescene; /* contains space boundaries */ |
| 27 |
|
| 28 |
extern COLOR ambval; /* global ambient component */ |
| 29 |
extern double ambacc; /* ambient accuracy */ |
| 30 |
extern int ambres; /* ambient resolution */ |
| 31 |
extern int ambdiv; /* number of divisions for calculation */ |
| 32 |
extern int ambssamp; /* number of super-samples */ |
| 33 |
extern int ambounce; /* number of ambient bounces */ |
| 34 |
extern char *amblist[]; /* ambient include/exclude list */ |
| 35 |
extern int ambincl; /* include == 1, exclude == 0 */ |
| 36 |
|
| 37 |
OBJECT ambset[128]; /* ambient include/exclude set */ |
| 38 |
|
| 39 |
double maxarad; /* maximum ambient radius */ |
| 40 |
double minarad; /* minimum ambient radius */ |
| 41 |
|
| 42 |
typedef struct ambval { |
| 43 |
FVECT pos; /* position in space */ |
| 44 |
FVECT dir; /* normal direction */ |
| 45 |
int lvl; /* recursion level of parent ray */ |
| 46 |
float weight; /* weight of parent ray */ |
| 47 |
COLOR val; /* computed ambient value */ |
| 48 |
float rad; /* validity radius */ |
| 49 |
struct ambval *next; /* next in list */ |
| 50 |
} AMBVAL; /* ambient value */ |
| 51 |
|
| 52 |
typedef struct ambtree { |
| 53 |
AMBVAL *alist; /* ambient value list */ |
| 54 |
struct ambtree *kid; /* 8 child nodes */ |
| 55 |
} AMBTREE; /* ambient octree */ |
| 56 |
|
| 57 |
typedef struct { |
| 58 |
float k; /* error contribution per sample */ |
| 59 |
COLOR v; /* ray sum */ |
| 60 |
int n; /* number of samples */ |
| 61 |
short t, p; /* theta, phi indices */ |
| 62 |
} AMBSAMP; /* ambient sample */ |
| 63 |
|
| 64 |
static AMBTREE atrunk; /* our ambient trunk node */ |
| 65 |
|
| 66 |
static FILE *ambfp = NULL; /* ambient file pointer */ |
| 67 |
|
| 68 |
#define newambval() (AMBVAL *)bmalloc(sizeof(AMBVAL)) |
| 69 |
|
| 70 |
#define newambtree() (AMBTREE *)calloc(8, sizeof(AMBTREE)) |
| 71 |
|
| 72 |
double sumambient(), doambient(), makeambient(); |
| 73 |
|
| 74 |
|
| 75 |
setambient(afile) /* initialize calculation */ |
| 76 |
char *afile; |
| 77 |
{ |
| 78 |
long ftell(); |
| 79 |
char **amblp; |
| 80 |
OBJECT obj; |
| 81 |
AMBVAL amb; |
| 82 |
/* set up ambient set */ |
| 83 |
ambset[0] = 0; |
| 84 |
for (amblp = amblist; *amblp != NULL; amblp++) { |
| 85 |
if ((obj = modifier(*amblp)) == OVOID) { |
| 86 |
sprintf(errmsg, "unknown %s modifier \"%s\"", |
| 87 |
ambincl ? "include" : "exclude", *amblp); |
| 88 |
error(WARNING, errmsg); |
| 89 |
continue; |
| 90 |
} |
| 91 |
if (!inset(ambset, obj)) |
| 92 |
insertelem(ambset, obj); |
| 93 |
} |
| 94 |
maxarad = thescene.cusize / 2.0; /* maximum radius */ |
| 95 |
/* minimum radius */ |
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minarad = ambres > 0 ? thescene.cusize/ambres : 0.0; |
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|
| 98 |
/* open ambient file */ |
| 99 |
if (afile != NULL) |
| 100 |
if ((ambfp = fopen(afile, "r+")) != NULL) { |
| 101 |
while (fread(&amb, sizeof(AMBVAL), 1, ambfp) == 1) |
| 102 |
avinsert(&amb, &atrunk, thescene.cuorg, |
| 103 |
thescene.cusize); |
| 104 |
/* align */ |
| 105 |
fseek(ambfp, -(ftell(ambfp)%sizeof(AMBVAL)), 1); |
| 106 |
} else if ((ambfp = fopen(afile, "w")) == NULL) { |
| 107 |
sprintf(errmsg, "cannot open ambient file \"%s\"", |
| 108 |
afile); |
| 109 |
error(SYSTEM, errmsg); |
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} |
| 111 |
} |
| 112 |
|
| 113 |
|
| 114 |
ambient(acol, r) /* compute ambient component for ray */ |
| 115 |
COLOR acol; |
| 116 |
register RAY *r; |
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{ |
| 118 |
static int rdepth = 0; /* ambient recursion */ |
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double wsum; |
| 120 |
|
| 121 |
rdepth++; /* increment level */ |
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|
| 123 |
if (ambdiv <= 0) /* no ambient calculation */ |
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goto dumbamb; |
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/* check number of bounces */ |
| 126 |
if (rdepth > ambounce) |
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goto dumbamb; |
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/* check ambient list */ |
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if (ambincl != -1 && r->ro != NULL && |
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ambincl != inset(ambset, r->ro->omod)) |
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goto dumbamb; |
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|
| 133 |
if (ambacc <= FTINY) { /* no ambient storage */ |
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if (doambient(acol, r) == 0.0) |
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goto dumbamb; |
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goto done; |
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} |
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/* get ambient value */ |
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setcolor(acol, 0.0, 0.0, 0.0); |
| 140 |
wsum = sumambient(acol, r, &atrunk, thescene.cuorg, thescene.cusize); |
| 141 |
if (wsum > FTINY) |
| 142 |
scalecolor(acol, 1.0/wsum); |
| 143 |
else if (makeambient(acol, r) == 0.0) |
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goto dumbamb; |
| 145 |
goto done; |
| 146 |
|
| 147 |
dumbamb: /* return global value */ |
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copycolor(acol, ambval); |
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done: /* must finish here! */ |
| 150 |
rdepth--; |
| 151 |
} |
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|
| 153 |
|
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double |
| 155 |
sumambient(acol, r, at, c0, s) /* get interpolated ambient value */ |
| 156 |
COLOR acol; |
| 157 |
register RAY *r; |
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AMBTREE *at; |
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FVECT c0; |
| 160 |
double s; |
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{ |
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extern double sqrt(); |
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double d, e1, e2, wt, wsum; |
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COLOR ct; |
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FVECT ck0; |
| 166 |
int i; |
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register int j; |
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register AMBVAL *av; |
| 169 |
|
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wsum = 0.0; |
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/* check children first */ |
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if (at->kid != NULL) { |
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s *= 0.5; |
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for (i = 0; i < 8; i++) { |
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for (j = 0; j < 3; j++) { |
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ck0[j] = c0[j]; |
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if (1<<j & i) |
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ck0[j] += s; |
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if (r->rop[j] < ck0[j] - OCTSCALE*s) |
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break; |
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if (r->rop[j] > ck0[j] + (1.0+OCTSCALE)*s) |
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break; |
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} |
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if (j == 3) |
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wsum += sumambient(acol, r, at->kid+i, ck0, s); |
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} |
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if (wsum*ambacc >= WDONE) |
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return(wsum); /* close enough */ |
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} |
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/* check this node */ |
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for (av = at->alist; av != NULL; av = av->next) { |
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/* |
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* Ray strength test. |
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*/ |
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if (av->lvl > r->rlvl || av->weight < r->rweight-FTINY) |
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continue; |
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/* |
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* Ambient radius test. |
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*/ |
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e1 = 0.0; |
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for (j = 0; j < 3; j++) { |
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d = av->pos[j] - r->rop[j]; |
| 203 |
e1 += d * d; |
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} |
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e1 /= av->rad * av->rad; |
| 206 |
if (e1 > ambacc*ambacc*1.21) |
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continue; |
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/* |
| 209 |
* Normal direction test. |
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*/ |
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e2 = (1.0 - DOT(av->dir, r->ron)) * r->rweight; |
| 212 |
if (e2 < 0.0) e2 = 0.0; |
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if (e1 + e2 > ambacc*ambacc*1.21) |
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continue; |
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/* |
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* Ray behind test. |
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*/ |
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d = 0.0; |
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for (j = 0; j < 3; j++) |
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d += (r->rop[j] - av->pos[j]) * |
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(av->dir[j] + r->ron[j]); |
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if (d < -minarad) |
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continue; |
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/* |
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* Jittering final test reduces image artifacts. |
| 226 |
*/ |
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wt = sqrt(e1) + sqrt(e2); |
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wt *= 0.9 + 0.2*frandom(); |
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if (wt > ambacc) |
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continue; |
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if (wt <= 1e-3) |
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wt = 1e3; |
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else |
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wt = 1.0 / wt; |
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wsum += wt; |
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copycolor(ct, av->val); |
| 237 |
scalecolor(ct, wt); |
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addcolor(acol, ct); |
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} |
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return(wsum); |
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} |
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|
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|
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double |
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makeambient(acol, r) /* make a new ambient value */ |
| 246 |
COLOR acol; |
| 247 |
register RAY *r; |
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{ |
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AMBVAL amb; |
| 250 |
|
| 251 |
amb.rad = doambient(acol, r); /* compute ambient */ |
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if (amb.rad == 0.0) |
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return(0.0); |
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/* store it */ |
| 255 |
VCOPY(amb.pos, r->rop); |
| 256 |
VCOPY(amb.dir, r->ron); |
| 257 |
amb.lvl = r->rlvl; |
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amb.weight = r->rweight; |
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copycolor(amb.val, acol); |
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/* insert into tree */ |
| 261 |
avinsert(&amb, &atrunk, thescene.cuorg, thescene.cusize); |
| 262 |
avsave(&amb); /* write to file */ |
| 263 |
return(amb.rad); |
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} |
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|
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|
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double |
| 268 |
doambient(acol, r) /* compute ambient component */ |
| 269 |
COLOR acol; |
| 270 |
register RAY *r; |
| 271 |
{ |
| 272 |
extern int ambcmp(); |
| 273 |
extern double sin(), cos(), sqrt(); |
| 274 |
double phi, xd, yd, zd; |
| 275 |
double b, b2; |
| 276 |
register AMBSAMP *div; |
| 277 |
AMBSAMP dnew; |
| 278 |
RAY ar; |
| 279 |
FVECT ux, uy; |
| 280 |
double arad; |
| 281 |
int ndivs, nt, np, ns, ne, i, j; |
| 282 |
register int k; |
| 283 |
|
| 284 |
setcolor(acol, 0.0, 0.0, 0.0); |
| 285 |
/* set number of divisions */ |
| 286 |
nt = sqrt(ambdiv * r->rweight * 0.5) + 0.5; |
| 287 |
np = 2 * nt; |
| 288 |
ndivs = nt * np; |
| 289 |
/* check first */ |
| 290 |
if (ndivs == 0 || rayorigin(&ar, r, AMBIENT, 0.5) < 0) |
| 291 |
return(0.0); |
| 292 |
/* set number of super-samples */ |
| 293 |
ns = ambssamp * r->rweight + 0.5; |
| 294 |
if (ns > 0) { |
| 295 |
div = (AMBSAMP *)malloc(ndivs*sizeof(AMBSAMP)); |
| 296 |
if (div == NULL) |
| 297 |
error(SYSTEM, "out of memory in doambient"); |
| 298 |
} |
| 299 |
/* make axes */ |
| 300 |
uy[0] = uy[1] = uy[2] = 0.0; |
| 301 |
for (k = 0; k < 3; k++) |
| 302 |
if (r->ron[k] < 0.6 && r->ron[k] > -0.6) |
| 303 |
break; |
| 304 |
uy[k] = 1.0; |
| 305 |
fcross(ux, r->ron, uy); |
| 306 |
normalize(ux); |
| 307 |
fcross(uy, ux, r->ron); |
| 308 |
/* sample divisions */ |
| 309 |
arad = 0.0; |
| 310 |
ne = 0; |
| 311 |
for (i = 0; i < nt; i++) |
| 312 |
for (j = 0; j < np; j++) { |
| 313 |
rayorigin(&ar, r, AMBIENT, 0.5); /* pretested */ |
| 314 |
zd = sqrt((i+frandom())/nt); |
| 315 |
phi = 2.0*PI * (j+frandom())/np; |
| 316 |
xd = cos(phi) * zd; |
| 317 |
yd = sin(phi) * zd; |
| 318 |
zd = sqrt(1.0 - zd*zd); |
| 319 |
for (k = 0; k < 3; k++) |
| 320 |
ar.rdir[k] = xd*ux[k]+yd*uy[k]+zd*r->ron[k]; |
| 321 |
rayvalue(&ar); |
| 322 |
if (ar.rot < FHUGE) |
| 323 |
arad += 1.0 / ar.rot; |
| 324 |
if (ns > 0) { /* save division */ |
| 325 |
div[ne].k = 0.0; |
| 326 |
copycolor(div[ne].v, ar.rcol); |
| 327 |
div[ne].n = 0; |
| 328 |
div[ne].t = i; div[ne].p = j; |
| 329 |
/* sum errors */ |
| 330 |
b = bright(ar.rcol); |
| 331 |
if (i > 0) { /* from above */ |
| 332 |
b2 = bright(div[ne-np].v) - b; |
| 333 |
b2 *= b2 * 0.25; |
| 334 |
div[ne].k += b2; |
| 335 |
div[ne].n++; |
| 336 |
div[ne-np].k += b2; |
| 337 |
div[ne-np].n++; |
| 338 |
} |
| 339 |
if (j > 0) { /* from behind */ |
| 340 |
b2 = bright(div[ne-1].v) - b; |
| 341 |
b2 *= b2 * 0.25; |
| 342 |
div[ne].k += b2; |
| 343 |
div[ne].n++; |
| 344 |
div[ne-1].k += b2; |
| 345 |
div[ne-1].n++; |
| 346 |
} |
| 347 |
if (j == np-1) { /* around */ |
| 348 |
b2 = bright(div[ne-(np-1)].v) - b; |
| 349 |
b2 *= b2 * 0.25; |
| 350 |
div[ne].k += b2; |
| 351 |
div[ne].n++; |
| 352 |
div[ne-(np-1)].k += b2; |
| 353 |
div[ne-(np-1)].n++; |
| 354 |
} |
| 355 |
ne++; |
| 356 |
} else |
| 357 |
addcolor(acol, ar.rcol); |
| 358 |
} |
| 359 |
for (k = 0; k < ne; k++) { /* compute errors */ |
| 360 |
if (div[k].n > 1) |
| 361 |
div[k].k /= div[k].n; |
| 362 |
div[k].n = 1; |
| 363 |
} |
| 364 |
/* sort the divisions */ |
| 365 |
qsort(div, ne, sizeof(AMBSAMP), ambcmp); |
| 366 |
/* skim excess */ |
| 367 |
while (ne > ns) { |
| 368 |
ne--; |
| 369 |
addcolor(acol, div[ne].v); |
| 370 |
} |
| 371 |
/* super-sample */ |
| 372 |
for (i = ns; i > 0; i--) { |
| 373 |
rayorigin(&ar, r, AMBIENT, 0.5); /* pretested */ |
| 374 |
zd = sqrt((div[0].t+frandom())/nt); |
| 375 |
phi = 2.0*PI * (div[0].p+frandom())/np; |
| 376 |
xd = cos(phi) * zd; |
| 377 |
yd = sin(phi) * zd; |
| 378 |
zd = sqrt(1.0 - zd*zd); |
| 379 |
for (k = 0; k < 3; k++) |
| 380 |
ar.rdir[k] = xd*ux[k]+yd*uy[k]+zd*r->ron[k]; |
| 381 |
rayvalue(&ar); |
| 382 |
if (ar.rot < FHUGE) |
| 383 |
arad += 1.0 / ar.rot; |
| 384 |
/* recompute error */ |
| 385 |
copycolor(dnew.v, div[0].v); |
| 386 |
addcolor(dnew.v, ar.rcol); |
| 387 |
dnew.n = div[0].n + 1; |
| 388 |
dnew.t = div[0].t; dnew.p = div[0].p; |
| 389 |
b2 = bright(dnew.v)/dnew.n - bright(ar.rcol); |
| 390 |
b2 = b2*b2 + div[0].k*(div[0].n*div[0].n); |
| 391 |
dnew.k = b2/(dnew.n*dnew.n); |
| 392 |
/* reinsert */ |
| 393 |
for (k = 0; k < ne-1 && dnew.k < div[k+1].k; k++) |
| 394 |
bcopy(&div[k+1], &div[k], sizeof(AMBSAMP)); |
| 395 |
bcopy(&dnew, &div[k], sizeof(AMBSAMP)); |
| 396 |
|
| 397 |
if (ne >= i) { /* extract darkest division */ |
| 398 |
ne--; |
| 399 |
if (div[ne].n > 1) |
| 400 |
scalecolor(div[ne].v, 1.0/div[ne].n); |
| 401 |
addcolor(acol, div[ne].v); |
| 402 |
} |
| 403 |
} |
| 404 |
scalecolor(acol, 1.0/ndivs); |
| 405 |
if (arad <= FTINY) |
| 406 |
arad = FHUGE; |
| 407 |
else |
| 408 |
arad = (ndivs+ns) / arad / sqrt(r->rweight); |
| 409 |
if (arad > maxarad) |
| 410 |
arad = maxarad; |
| 411 |
else if (arad < minarad) |
| 412 |
arad = minarad; |
| 413 |
if (ns > 0) |
| 414 |
free((char *)div); |
| 415 |
return(arad); |
| 416 |
} |
| 417 |
|
| 418 |
|
| 419 |
static int |
| 420 |
ambcmp(d1, d2) /* decreasing order */ |
| 421 |
AMBSAMP *d1, *d2; |
| 422 |
{ |
| 423 |
if (d1->k < d2->k) |
| 424 |
return(1); |
| 425 |
if (d1->k > d2->k) |
| 426 |
return(-1); |
| 427 |
return(0); |
| 428 |
} |
| 429 |
|
| 430 |
|
| 431 |
static |
| 432 |
avsave(av) /* save an ambient value */ |
| 433 |
AMBVAL *av; |
| 434 |
{ |
| 435 |
#ifdef AMBFLUSH |
| 436 |
static int nunflshed = 0; |
| 437 |
#endif |
| 438 |
if (ambfp == NULL) |
| 439 |
return; |
| 440 |
if (fwrite(av, sizeof(AMBVAL), 1, ambfp) != 1) |
| 441 |
goto writerr; |
| 442 |
#ifdef AMBFLUSH |
| 443 |
if (++nunflshed >= AMBFLUSH) { |
| 444 |
if (fflush(ambfp) == EOF) |
| 445 |
goto writerr; |
| 446 |
nunflshed = 0; |
| 447 |
} |
| 448 |
#endif |
| 449 |
return; |
| 450 |
writerr: |
| 451 |
error(SYSTEM, "error writing ambient file"); |
| 452 |
} |
| 453 |
|
| 454 |
|
| 455 |
static |
| 456 |
avinsert(aval, at, c0, s) /* insert ambient value in a tree */ |
| 457 |
AMBVAL *aval; |
| 458 |
register AMBTREE *at; |
| 459 |
FVECT c0; |
| 460 |
double s; |
| 461 |
{ |
| 462 |
FVECT ck0; |
| 463 |
int branch; |
| 464 |
register AMBVAL *av; |
| 465 |
register int i; |
| 466 |
|
| 467 |
if ((av = newambval()) == NULL) |
| 468 |
goto memerr; |
| 469 |
bcopy(aval, av, sizeof(AMBVAL)); |
| 470 |
VCOPY(ck0, c0); |
| 471 |
while (s*(OCTSCALE/2) > av->rad*ambacc) { |
| 472 |
if (at->kid == NULL) |
| 473 |
if ((at->kid = newambtree()) == NULL) |
| 474 |
goto memerr; |
| 475 |
s *= 0.5; |
| 476 |
branch = 0; |
| 477 |
for (i = 0; i < 3; i++) |
| 478 |
if (av->pos[i] > ck0[i] + s) { |
| 479 |
ck0[i] += s; |
| 480 |
branch |= 1 << i; |
| 481 |
} |
| 482 |
at = at->kid + branch; |
| 483 |
} |
| 484 |
av->next = at->alist; |
| 485 |
at->alist = av; |
| 486 |
return; |
| 487 |
memerr: |
| 488 |
error(SYSTEM, "out of memory in avinsert"); |
| 489 |
} |
