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/* Copyright (c) 1991 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" |
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|
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#include "otypes.h" |
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|
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#include "ambient.h" |
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|
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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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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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extern CUBE thescene; /* contains space boundaries */ |
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|
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#define MAXASET 511 /* maximum number of elements in ambient set */ |
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OBJECT ambset[MAXASET+1]={0}; /* 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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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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|
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setambres(ar) /* set ambient resolution */ |
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int ar; |
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{ |
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/* set min & max radii */ |
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if (ar <= 0) { |
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minarad = 0.0; |
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maxarad = thescene.cusize / 2.0; |
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} else { |
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minarad = thescene.cusize / ar; |
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maxarad = 16.0 * minarad; /* heuristic */ |
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if (maxarad > thescene.cusize / 2.0) |
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maxarad = thescene.cusize / 2.0; |
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} |
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} |
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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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AMBVAL amb; |
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/* init ambient limits */ |
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setambres(ambres); |
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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((char *)&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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ambnotify(obj) /* record new modifier */ |
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OBJECT obj; |
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{ |
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static int hitlimit = 0; |
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register OBJREC *o = objptr(obj); |
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register char **amblp; |
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|
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if (hitlimit || !ismodifier(o->otype)) |
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return; |
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for (amblp = amblist; *amblp != NULL; amblp++) |
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if (!strcmp(o->oname, *amblp)) { |
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if (ambset[0] >= MAXASET) { |
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error(WARNING, "too many modifiers in ambient list"); |
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hitlimit++; |
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return; /* should this be fatal? */ |
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} |
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insertelem(ambset, obj); |
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return; |
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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 d; |
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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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rdepth++; |
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d = doambient(acol, r, r->rweight, NULL, NULL); |
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rdepth--; |
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if (d == 0.0) |
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goto dumbamb; |
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return; |
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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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d = sumambient(acol, r, rdepth, |
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&atrunk, thescene.cuorg, thescene.cusize); |
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if (d > FTINY) |
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scalecolor(acol, 1.0/d); |
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else { |
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d = makeambient(acol, r, rdepth++); |
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rdepth--; |
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} |
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if (d > FTINY) |
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return; |
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dumbamb: /* return global value */ |
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copycolor(acol, ambval); |
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} |
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|
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|
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double |
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sumambient(acol, r, al, at, c0, s) /* get interpolated ambient value */ |
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COLOR acol; |
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register RAY *r; |
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int al; |
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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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/* do this node */ |
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wsum = 0.0; |
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for (av = at->alist; av != NULL; av = av->next) { |
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/* |
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* Ambient level test. |
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*/ |
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if (av->lvl > al || 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*0.5 < -minarad*ambacc-.001) |
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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 *= .9 + .2*urand(9015+samplendx); |
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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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extambient(ct, av, r->rop, r->ron); |
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scalecolor(ct, wt); |
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addcolor(acol, ct); |
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} |
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if (at->kid == NULL) |
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return(wsum); |
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/* do children */ |
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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, al, at->kid+i, ck0, s); |
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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, al) /* make a new ambient value */ |
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COLOR acol; |
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register RAY *r; |
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int al; |
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{ |
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AMBVAL amb; |
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FVECT gp, gd; |
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/* compute weight */ |
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amb.weight = pow(AVGREFL, (double)al); |
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if (r->rweight < 0.2*amb.weight) /* heuristic */ |
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amb.weight = r->rweight; |
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/* compute ambient */ |
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amb.rad = doambient(acol, r, amb.weight, gp, gd); |
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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 = al; |
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copycolor(amb.val, acol); |
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VCOPY(amb.gpos, gp); |
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VCOPY(amb.gdir, gd); |
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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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extambient(cr, ap, pv, nv) /* extrapolate value at pv, nv */ |
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COLOR cr; |
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register AMBVAL *ap; |
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FVECT pv, nv; |
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{ |
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FVECT v1, v2; |
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register int i; |
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double d; |
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|
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d = 1.0; /* zeroeth order */ |
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/* gradient due to translation */ |
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for (i = 0; i < 3; i++) |
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d += ap->gpos[i]*(pv[i]-ap->pos[i]); |
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/* gradient due to rotation */ |
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VCOPY(v1, ap->dir); |
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fcross(v2, v1, nv); |
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d += DOT(ap->gdir, v2); |
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if (d <= 0.0) { |
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setcolor(cr, 0.0, 0.0, 0.0); |
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return; |
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} |
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copycolor(cr, ap->val); |
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scalecolor(cr, d); |
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} |
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|
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|
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static |
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avsave(av) /* save an ambient value */ |
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AMBVAL *av; |
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{ |
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#ifdef AMBFLUSH |
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static int nunflshed = 0; |
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#endif |
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if (ambfp == NULL) |
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return; |
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if (fwrite((char *)av, sizeof(AMBVAL), 1, ambfp) != 1) |
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goto writerr; |
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#ifdef AMBFLUSH |
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if (++nunflshed >= AMBFLUSH) { |
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if (fflush(ambfp) == EOF) |
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goto writerr; |
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nunflshed = 0; |
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} |
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#endif |
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return; |
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writerr: |
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error(SYSTEM, "error writing ambient file"); |
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} |
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|
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|
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static |
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avinsert(aval, at, c0, s) /* insert ambient value in a tree */ |
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AMBVAL *aval; |
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register AMBTREE *at; |
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FVECT c0; |
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double s; |
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{ |
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FVECT ck0; |
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int branch; |
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register AMBVAL *av; |
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register int i; |
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|
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if ((av = newambval()) == NULL) |
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goto memerr; |
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copystruct(av, aval); |
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VCOPY(ck0, c0); |
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while (s*(OCTSCALE/2) > av->rad*ambacc) { |
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if (at->kid == NULL) |
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if ((at->kid = newambtree()) == NULL) |
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goto memerr; |
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s *= 0.5; |
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branch = 0; |
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for (i = 0; i < 3; i++) |
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if (av->pos[i] > ck0[i] + s) { |
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ck0[i] += s; |
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branch |= 1 << i; |
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} |
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at = at->kid + branch; |
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} |
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av->next = at->alist; |
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at->alist = av; |
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return; |
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memerr: |
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error(SYSTEM, "out of memory in avinsert"); |
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} |
