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/* Copyright (c) 1986 Regents of the University of California */ |
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|
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#ifndef lint |
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static char SCCSid[] = "$SunId$ LBL"; |
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#endif |
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|
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/* |
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* ambient.c - routines dealing with ambient (inter-reflected) component. |
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* |
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* The macro AMBFLUSH (if defined) is the number of ambient values |
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* to wait before flushing to the ambient file. |
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* |
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* 5/9/86 |
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*/ |
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|
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#include "ray.h" |
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|
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#include "octree.h" |
19 |
|
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#include "random.h" |
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|
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#define OCTSCALE 0.5 /* ceil((valid rad.)/(cube size)) */ |
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|
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#define WDONE 4 /* stop if wsum/wmin is at or above */ |
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|
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extern CUBE thescene; /* contains space boundaries */ |
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|
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extern COLOR ambval; /* global ambient component */ |
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extern double ambacc; /* ambient accuracy */ |
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extern int ambres; /* ambient resolution */ |
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extern int ambdiv; /* number of divisions for calculation */ |
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extern int ambssamp; /* number of super-samples */ |
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extern int ambounce; /* number of ambient bounces */ |
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extern char *amblist[]; /* ambient include/exclude list */ |
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extern int ambincl; /* include == 1, exclude == 0 */ |
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|
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OBJECT ambset[128]; /* ambient include/exclude set */ |
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|
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double maxarad; /* maximum ambient radius */ |
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double minarad; /* minimum ambient radius */ |
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|
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typedef struct ambval { |
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FVECT pos; /* position in space */ |
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FVECT dir; /* normal direction */ |
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int lvl; /* recursion level of parent ray */ |
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float weight; /* weight of parent ray */ |
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COLOR val; /* computed ambient value */ |
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float rad; /* validity radius */ |
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struct ambval *next; /* next in list */ |
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} AMBVAL; /* ambient value */ |
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|
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typedef struct ambtree { |
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AMBVAL *alist; /* ambient value list */ |
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struct ambtree *kid; /* 8 child nodes */ |
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} AMBTREE; /* ambient octree */ |
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|
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typedef struct { |
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float k; /* error contribution per sample */ |
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COLOR v; /* ray sum */ |
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int n; /* number of samples */ |
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short t, p; /* theta, phi indices */ |
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} AMBSAMP; /* ambient sample */ |
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|
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static AMBTREE atrunk; /* our ambient trunk node */ |
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|
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static FILE *ambfp = NULL; /* ambient file pointer */ |
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|
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#define newambval() (AMBVAL *)bmalloc(sizeof(AMBVAL)) |
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|
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#define newambtree() (AMBTREE *)calloc(8, sizeof(AMBTREE)) |
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|
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double sumambient(), doambient(), makeambient(); |
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|
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|
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setambient(afile) /* initialize calculation */ |
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char *afile; |
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{ |
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long ftell(); |
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char **amblp; |
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OBJECT obj; |
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AMBVAL amb; |
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/* set up ambient set */ |
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ambset[0] = 0; |
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for (amblp = amblist; *amblp != NULL; amblp++) { |
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if ((obj = modifier(*amblp)) == OVOID) { |
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sprintf(errmsg, "unknown %s modifier \"%s\"", |
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ambincl ? "include" : "exclude", *amblp); |
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error(WARNING, errmsg); |
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continue; |
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} |
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if (!inset(ambset, obj)) |
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insertelem(ambset, obj); |
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} |
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maxarad = thescene.cusize / 2.0; /* maximum radius */ |
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/* minimum radius */ |
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minarad = ambres > 0 ? thescene.cusize/ambres : 0.0; |
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|
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/* open ambient file */ |
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if (afile != NULL) |
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if ((ambfp = fopen(afile, "r+")) != NULL) { |
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while (fread(&amb, sizeof(AMBVAL), 1, ambfp) == 1) |
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avinsert(&amb, &atrunk, thescene.cuorg, |
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thescene.cusize); |
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/* align */ |
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fseek(ambfp, -(ftell(ambfp)%sizeof(AMBVAL)), 1); |
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} else if ((ambfp = fopen(afile, "w")) == NULL) { |
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sprintf(errmsg, "cannot open ambient file \"%s\"", |
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afile); |
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error(SYSTEM, errmsg); |
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} |
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} |
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|
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|
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ambient(acol, r) /* compute ambient component for ray */ |
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COLOR acol; |
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register RAY *r; |
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{ |
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static int rdepth = 0; /* ambient recursion */ |
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double wsum; |
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|
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rdepth++; /* increment level */ |
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|
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if (ambdiv <= 0) /* no ambient calculation */ |
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goto dumbamb; |
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/* check number of bounces */ |
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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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|
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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); |
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wsum = sumambient(acol, r, &atrunk, thescene.cuorg, thescene.cusize); |
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if (wsum > FTINY) |
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scalecolor(acol, 1.0/wsum); |
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else if (makeambient(acol, r) == 0.0) |
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goto dumbamb; |
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goto done; |
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|
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dumbamb: /* return global value */ |
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copycolor(acol, ambval); |
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done: /* must finish here! */ |
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rdepth--; |
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} |
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|
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|
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double |
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sumambient(acol, r, at, c0, s) /* get interpolated ambient value */ |
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COLOR acol; |
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register RAY *r; |
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AMBTREE *at; |
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FVECT c0; |
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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; |
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int i; |
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register int j; |
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register AMBVAL *av; |
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|
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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]; |
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e1 += d * d; |
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} |
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e1 /= av->rad * av->rad; |
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if (e1 > ambacc*ambacc*1.21) |
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continue; |
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/* |
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* Normal direction test. |
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*/ |
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e2 = (1.0 - DOT(av->dir, r->ron)) * r->rweight; |
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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. |
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*/ |
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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); |
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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 */ |
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COLOR acol; |
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register RAY *r; |
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{ |
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AMBVAL amb; |
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|
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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 */ |
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VCOPY(amb.pos, r->rop); |
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VCOPY(amb.dir, r->ron); |
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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 */ |
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avinsert(&amb, &atrunk, thescene.cuorg, thescene.cusize); |
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avsave(&amb); /* write to file */ |
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return(amb.rad); |
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} |
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|
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|
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double |
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doambient(acol, r) /* compute ambient component */ |
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COLOR acol; |
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register RAY *r; |
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{ |
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extern int ambcmp(); |
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extern double sin(), cos(), sqrt(); |
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double phi, xd, yd, zd; |
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double b, b2; |
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register AMBSAMP *div; |
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AMBSAMP dnew; |
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RAY ar; |
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FVECT ux, uy; |
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double arad; |
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int ndivs, nt, np, ns, ne, i, j; |
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register int k; |
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|
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setcolor(acol, 0.0, 0.0, 0.0); |
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/* set number of divisions */ |
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nt = sqrt(ambdiv * r->rweight * 0.5) + 0.5; |
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np = 2 * nt; |
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ndivs = nt * np; |
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/* check first */ |
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if (ndivs == 0 || rayorigin(&ar, r, AMBIENT, 0.5) < 0) |
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return(0.0); |
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/* set number of super-samples */ |
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ns = ambssamp * r->rweight + 0.5; |
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if (ns > 0) { |
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div = (AMBSAMP *)malloc(ndivs*sizeof(AMBSAMP)); |
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if (div == NULL) |
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error(SYSTEM, "out of memory in doambient"); |
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} |
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/* make axes */ |
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uy[0] = uy[1] = uy[2] = 0.0; |
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for (k = 0; k < 3; k++) |
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if (r->ron[k] < 0.6 && r->ron[k] > -0.6) |
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break; |
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uy[k] = 1.0; |
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fcross(ux, r->ron, uy); |
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normalize(ux); |
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fcross(uy, ux, r->ron); |
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/* sample divisions */ |
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arad = 0.0; |
310 |
ne = 0; |
311 |
for (i = 0; i < nt; i++) |
312 |
for (j = 0; j < np; j++) { |
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rayorigin(&ar, r, AMBIENT, 0.5); /* pretested */ |
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zd = sqrt((i+frandom())/nt); |
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phi = 2.0*PI * (j+frandom())/np; |
316 |
xd = cos(phi) * zd; |
317 |
yd = sin(phi) * zd; |
318 |
zd = sqrt(1.0 - zd*zd); |
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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 |
} |