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#ifndef lint |
| 2 |
static const char RCSid[] = "$Id: srcsamp.c,v 2.21 2024/11/09 15:21:32 greg Exp $"; |
| 3 |
#endif |
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/* |
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* Source sampling routines |
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* |
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* External symbols declared in source.h |
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*/ |
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|
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#include "copyright.h" |
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|
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#include "ray.h" |
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|
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#include "source.h" |
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|
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#include "random.h" |
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|
| 18 |
#ifdef SSKIPOPT |
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/* The following table is used for skipping sources */ |
| 20 |
static uby8 *srcskipflags = NULL; /* source inclusion lookup */ |
| 21 |
static int ssf_count = 0; /* number of flag entries */ |
| 22 |
static int ssf_max = 0; /* current array size */ |
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static uby8 *ssf_noskip = NULL; /* set of zero flags */ |
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|
| 25 |
uby8 *ssf_select = NULL; /* sources we may skip */ |
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|
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/* Find/allocate source skip flag entry (free all if NULL) */ |
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int |
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sskip_rsi(uby8 *flags) |
| 30 |
{ |
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uby8 *flp; |
| 32 |
int i; |
| 33 |
|
| 34 |
if (flags == NULL) { /* means clear all */ |
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efree(srcskipflags); srcskipflags = NULL; |
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ssf_count = ssf_max = 0; |
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sskip_free(ssf_noskip); |
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sskip_free(ssf_select); |
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return(0); |
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} |
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if (ssf_noskip == NULL) /* first call? */ |
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ssf_noskip = sskip_new(); |
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|
| 44 |
if (sskip_eq(flags, ssf_noskip)) |
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return(-1); /* nothing to skip */ |
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/* search recent entries */ |
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flp = srcskipflags + ssf_count*SSKIPFLSIZ; |
| 48 |
for (i = ssf_count; i-- > 0; ) |
| 49 |
if (sskip_eq(flp -= SSKIPFLSIZ, flags)) |
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return(-2-i); /* found it! */ |
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/* else tack on new entry */ |
| 52 |
if (ssf_count >= ssf_max) { /* need more space? */ |
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fprintf(stderr, "DEBUG: skip flag array > %d entries (%.2f MBytes)\n", |
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ssf_count, SSKIPFLSIZ/1024./1024.*ssf_count); |
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ssf_max = ssf_count + (ssf_count>>2) + 64; |
| 56 |
if (ssf_max <= ssf_count && |
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(ssf_max = ssf_count+1024) <= ssf_count) |
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error(SYSTEM, "out of space in sskip_rsi()"); |
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|
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srcskipflags = (uby8 *)erealloc(srcskipflags, |
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ssf_max*SSKIPFLSIZ); |
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} |
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sskip_cpy(srcskipflags + ssf_count*SSKIPFLSIZ, flags); |
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|
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return(-2 - ssf_count++); /* return index (< -1) */ |
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} |
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|
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/* Get skip flags associated with RAY rsrc index (or NULL) */ |
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uby8 * |
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sskip_flags(int rsi) |
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{ |
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if (rsi >= -1) |
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return(ssf_noskip); |
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|
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if ((rsi = -2 - rsi) >= ssf_count) |
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error(CONSISTENCY, "bad index to sskip_flags()"); |
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|
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return(srcskipflags + rsi*SSKIPFLSIZ); |
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} |
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|
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/* OR in a second set of flags into a first */ |
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void |
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sskip_addflags(uby8 *dfl, const uby8 *sfl) |
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{ |
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int nb = SSKIPFLSIZ; |
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|
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while (nb--) |
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*dfl++ |= *sfl++; |
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} |
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#endif |
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|
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int |
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srcskip( /* pre-emptive test for source to skip */ |
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int sn, |
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RAY *r |
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) |
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{ |
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SRCREC *sp = source + sn; |
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|
| 100 |
if (sp->sflags & SSKIP) |
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return(1); |
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#ifdef SSKIPOPT |
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if (r->rsrc < -1 && /* ray has custom skip flags? */ |
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sskip_chk(sskip_flags(r->rsrc), sn)) |
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return(1); |
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#endif |
| 107 |
if ((sp->sflags & (SPROX|SDISTANT)) != SPROX) |
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return(0); |
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|
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return(dist2(r->rorg, sp->sloc) > |
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(sp->sl.prox + sp->srad)*(sp->sl.prox + sp->srad)); |
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} |
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|
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double |
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nextssamp( /* compute sample for source, rtn. distance */ |
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RAY *r, /* origin is read, direction is set */ |
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SRCINDEX *si /* source index (modified to current) */ |
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) |
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{ |
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int cent[3], size[3], parr[2]; |
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SRCREC *srcp; |
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double vpos[3]; |
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double d; |
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int i; |
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nextsample: |
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while (++si->sp >= si->np) { /* get next sample */ |
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if (++si->sn >= nsources) |
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return(0.0); /* no more */ |
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if (srcskip(si->sn, r)) |
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si->np = 0; |
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else if (srcsizerat <= FTINY) |
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nopart(si, r); |
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else { |
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for (i = si->sn; source[i].sflags & SVIRTUAL; |
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i = source[i].sa.sv.sn) |
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; /* partition source */ |
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(*sfun[source[i].so->otype].of->partit)(si, r); |
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} |
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si->sp = -1; |
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} |
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/* get partition */ |
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cent[0] = cent[1] = cent[2] = 0; |
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size[0] = size[1] = size[2] = MAXSPART; |
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parr[0] = 0; parr[1] = si->sp; |
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if (!skipparts(cent, size, parr, si->spt)) |
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error(CONSISTENCY, "bad source partition in nextssamp"); |
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/* compute sample */ |
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srcp = source + si->sn; |
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if (dstrsrc > FTINY) { /* jitter sample */ |
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dimlist[ndims] = si->sn + 8831; |
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dimlist[ndims+1] = si->sp + 3109; |
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d = urand(ilhash(dimlist,ndims+2)+samplendx); |
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if (srcp->sflags & SFLAT) { |
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multisamp(vpos, 2, d); |
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vpos[SW] = 0.5; |
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} else |
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multisamp(vpos, 3, d); |
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for (i = 0; i < 3; i++) |
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vpos[i] = dstrsrc * (1. - 2.*vpos[i]) * |
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(double)size[i]*(1.0/MAXSPART); |
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} else |
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vpos[0] = vpos[1] = vpos[2] = 0.0; |
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|
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VSUM(vpos, vpos, cent, 1.0/MAXSPART); |
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/* avoid circular aiming failures */ |
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if ((srcp->sflags & SCIR) && (si->np > 1) | (dstrsrc > 0.7)) { |
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FVECT trim; |
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if (srcp->sflags & (SFLAT|SDISTANT)) { |
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d = 1.12837917; /* correct setflatss() */ |
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trim[SU] = d*sqrt(1.0 - 0.5*vpos[SV]*vpos[SV]); |
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trim[SV] = d*sqrt(1.0 - 0.5*vpos[SU]*vpos[SU]); |
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trim[SW] = 0.0; |
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} else { |
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trim[SW] = trim[SU] = vpos[SU]*vpos[SU]; |
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d = vpos[SV]*vpos[SV]; |
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if (d > trim[SW]) trim[SW] = d; |
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trim[SU] += d; |
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d = vpos[SW]*vpos[SW]; |
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if (d > trim[SW]) trim[SW] = d; |
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trim[SU] += d; |
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if (trim[SU] > FTINY*FTINY) { |
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d = 1.0/0.7236; /* correct sphsetsrc() */ |
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trim[SW] = trim[SV] = trim[SU] = |
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d*sqrt(trim[SW]/trim[SU]); |
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} else |
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trim[SW] = trim[SV] = trim[SU] = 0.0; |
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} |
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for (i = 0; i < 3; i++) |
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vpos[i] *= trim[i]; |
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} |
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/* compute direction */ |
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for (i = 0; i < 3; i++) |
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r->rdir[i] = srcp->sloc[i] + |
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vpos[SU]*srcp->ss[SU][i] + |
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vpos[SV]*srcp->ss[SV][i] + |
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vpos[SW]*srcp->ss[SW][i]; |
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|
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if (!(srcp->sflags & SDISTANT)) |
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VSUB(r->rdir, r->rdir, r->rorg); |
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/* compute distance */ |
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if ((d = normalize(r->rdir)) == 0.0) |
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goto nextsample; /* at source! */ |
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|
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/* compute sample size */ |
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if (srcp->sflags & SFLAT) { |
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si->dom = sflatform(si->sn, r->rdir); |
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si->dom *= size[SU]*size[SV]*(1.0/MAXSPART/MAXSPART); |
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} else if (srcp->sflags & SCYL) { |
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si->dom = scylform(si->sn, r->rdir); |
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si->dom *= size[SU]*(1.0/MAXSPART); |
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} else { |
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si->dom = size[SU]*size[SV]*(double)size[SW] * |
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(1.0/MAXSPART/MAXSPART/MAXSPART) ; |
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} |
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if (srcp->sflags & SDISTANT) { |
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si->dom *= srcp->ss2; |
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return(FHUGE); |
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} |
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if (si->dom <= 1e-4) |
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goto nextsample; /* behind source? */ |
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si->dom *= srcp->ss2/(d*d); |
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return(d); /* sample OK, return distance */ |
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} |
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|
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|
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int |
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skipparts( /* skip to requested partition */ |
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int ct[3], |
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int sz[3], /* center and size of partition (returned) */ |
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int pp[2], /* current index, number to skip (modified) */ |
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unsigned char *pt /* partition array */ |
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) |
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{ |
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int p; |
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/* check this partition */ |
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p = spart(pt, pp[0]); |
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pp[0]++; |
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if (p == S0) { /* leaf partition */ |
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if (pp[1]) { |
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pp[1]--; |
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return(0); /* not there yet */ |
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} else |
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return(1); /* we've arrived */ |
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} |
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/* else check lower */ |
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sz[p] >>= 1; |
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ct[p] -= sz[p]; |
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if (skipparts(ct, sz, pp, pt)) |
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return(1); /* return hit */ |
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/* else check upper */ |
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ct[p] += sz[p] << 1; |
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if (skipparts(ct, sz, pp, pt)) |
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return(1); /* return hit */ |
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/* else return to starting position */ |
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ct[p] -= sz[p]; |
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sz[p] <<= 1; |
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return(0); /* return miss */ |
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} |
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|
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|
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void |
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nopart( /* single source partition */ |
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SRCINDEX *si, |
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RAY *r |
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) |
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{ |
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clrpart(si->spt); |
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setpart(si->spt, 0, S0); |
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si->np = 1; |
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} |
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|
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|
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static int |
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cyl_partit( /* slice a cylinder */ |
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FVECT ro, |
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unsigned char *pt, |
| 277 |
int *pi, |
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int mp, |
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FVECT cent, |
| 280 |
FVECT axis, |
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double d2 |
| 282 |
) |
| 283 |
{ |
| 284 |
FVECT newct, newax; |
| 285 |
int npl, npu; |
| 286 |
|
| 287 |
if (mp < 2 || dist2(ro, cent) >= d2) { /* hit limit? */ |
| 288 |
setpart(pt, *pi, S0); |
| 289 |
(*pi)++; |
| 290 |
return(1); |
| 291 |
} |
| 292 |
/* subdivide */ |
| 293 |
setpart(pt, *pi, SU); |
| 294 |
(*pi)++; |
| 295 |
newax[0] = .5*axis[0]; |
| 296 |
newax[1] = .5*axis[1]; |
| 297 |
newax[2] = .5*axis[2]; |
| 298 |
d2 *= 0.25; |
| 299 |
/* lower half */ |
| 300 |
newct[0] = cent[0] - newax[0]; |
| 301 |
newct[1] = cent[1] - newax[1]; |
| 302 |
newct[2] = cent[2] - newax[2]; |
| 303 |
npl = cyl_partit(ro, pt, pi, mp/2, newct, newax, d2); |
| 304 |
/* upper half */ |
| 305 |
newct[0] = cent[0] + newax[0]; |
| 306 |
newct[1] = cent[1] + newax[1]; |
| 307 |
newct[2] = cent[2] + newax[2]; |
| 308 |
npu = cyl_partit(ro, pt, pi, mp/2, newct, newax, d2); |
| 309 |
/* return total */ |
| 310 |
return(npl + npu); |
| 311 |
} |
| 312 |
|
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|
| 314 |
void |
| 315 |
cylpart( /* partition a cylinder */ |
| 316 |
SRCINDEX *si, |
| 317 |
RAY *r |
| 318 |
) |
| 319 |
{ |
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double dist2, safedist2, dist2cent, rad2; |
| 321 |
FVECT v; |
| 322 |
SRCREC *sp; |
| 323 |
int pi; |
| 324 |
/* first check point location */ |
| 325 |
clrpart(si->spt); |
| 326 |
sp = source + si->sn; |
| 327 |
rad2 = 1.365 * DOT(sp->ss[SV],sp->ss[SV]); |
| 328 |
v[0] = r->rorg[0] - sp->sloc[0]; |
| 329 |
v[1] = r->rorg[1] - sp->sloc[1]; |
| 330 |
v[2] = r->rorg[2] - sp->sloc[2]; |
| 331 |
dist2 = DOT(v,sp->ss[SU]); |
| 332 |
safedist2 = DOT(sp->ss[SU],sp->ss[SU]); |
| 333 |
dist2 *= dist2 / safedist2; |
| 334 |
dist2cent = DOT(v,v); |
| 335 |
dist2 = dist2cent - dist2; |
| 336 |
if (dist2 <= rad2) { /* point inside extended cylinder */ |
| 337 |
si->np = 0; |
| 338 |
return; |
| 339 |
} |
| 340 |
safedist2 *= 4.*r->rweight*r->rweight/(srcsizerat*srcsizerat); |
| 341 |
if (dist2 <= 4.*rad2 || /* point too close to subdivide */ |
| 342 |
dist2cent >= safedist2) { /* or too far */ |
| 343 |
setpart(si->spt, 0, S0); |
| 344 |
si->np = 1; |
| 345 |
return; |
| 346 |
} |
| 347 |
pi = 0; |
| 348 |
si->np = cyl_partit(r->rorg, si->spt, &pi, MAXSPART, |
| 349 |
sp->sloc, sp->ss[SU], safedist2); |
| 350 |
} |
| 351 |
|
| 352 |
|
| 353 |
static int |
| 354 |
flt_partit( /* partition flatty */ |
| 355 |
FVECT ro, |
| 356 |
unsigned char *pt, |
| 357 |
int *pi, |
| 358 |
int mp, |
| 359 |
FVECT cent, |
| 360 |
FVECT u, |
| 361 |
FVECT v, |
| 362 |
double du2, |
| 363 |
double dv2 |
| 364 |
) |
| 365 |
{ |
| 366 |
double d2; |
| 367 |
FVECT newct, newax; |
| 368 |
int npl, npu; |
| 369 |
|
| 370 |
if (mp < 2 || ((d2 = dist2(ro, cent)) >= du2 |
| 371 |
&& d2 >= dv2)) { /* hit limit? */ |
| 372 |
setpart(pt, *pi, S0); |
| 373 |
(*pi)++; |
| 374 |
return(1); |
| 375 |
} |
| 376 |
if (du2 > dv2) { /* subdivide in U */ |
| 377 |
setpart(pt, *pi, SU); |
| 378 |
(*pi)++; |
| 379 |
newax[0] = .5*u[0]; |
| 380 |
newax[1] = .5*u[1]; |
| 381 |
newax[2] = .5*u[2]; |
| 382 |
u = newax; |
| 383 |
du2 *= 0.25; |
| 384 |
} else { /* subdivide in V */ |
| 385 |
setpart(pt, *pi, SV); |
| 386 |
(*pi)++; |
| 387 |
newax[0] = .5*v[0]; |
| 388 |
newax[1] = .5*v[1]; |
| 389 |
newax[2] = .5*v[2]; |
| 390 |
v = newax; |
| 391 |
dv2 *= 0.25; |
| 392 |
} |
| 393 |
/* lower half */ |
| 394 |
newct[0] = cent[0] - newax[0]; |
| 395 |
newct[1] = cent[1] - newax[1]; |
| 396 |
newct[2] = cent[2] - newax[2]; |
| 397 |
npl = flt_partit(ro, pt, pi, mp/2, newct, u, v, du2, dv2); |
| 398 |
/* upper half */ |
| 399 |
newct[0] = cent[0] + newax[0]; |
| 400 |
newct[1] = cent[1] + newax[1]; |
| 401 |
newct[2] = cent[2] + newax[2]; |
| 402 |
npu = flt_partit(ro, pt, pi, mp/2, newct, u, v, du2, dv2); |
| 403 |
/* return total */ |
| 404 |
return(npl + npu); |
| 405 |
} |
| 406 |
|
| 407 |
|
| 408 |
void |
| 409 |
flatpart( /* partition a flat source */ |
| 410 |
SRCINDEX *si, |
| 411 |
RAY *r |
| 412 |
) |
| 413 |
{ |
| 414 |
RREAL *vp; |
| 415 |
FVECT v; |
| 416 |
double du2, dv2; |
| 417 |
int pi; |
| 418 |
|
| 419 |
clrpart(si->spt); |
| 420 |
vp = source[si->sn].sloc; |
| 421 |
v[0] = r->rorg[0] - vp[0]; |
| 422 |
v[1] = r->rorg[1] - vp[1]; |
| 423 |
v[2] = r->rorg[2] - vp[2]; |
| 424 |
vp = source[si->sn].snorm; |
| 425 |
if (DOT(v,vp) <= 0.) { /* behind source */ |
| 426 |
si->np = 0; |
| 427 |
return; |
| 428 |
} |
| 429 |
dv2 = 2.*r->rweight/srcsizerat; |
| 430 |
dv2 *= dv2; |
| 431 |
vp = source[si->sn].ss[SU]; |
| 432 |
du2 = dv2 * DOT(vp,vp); |
| 433 |
vp = source[si->sn].ss[SV]; |
| 434 |
dv2 *= DOT(vp,vp); |
| 435 |
pi = 0; |
| 436 |
si->np = flt_partit(r->rorg, si->spt, &pi, MAXSPART, |
| 437 |
source[si->sn].sloc, |
| 438 |
source[si->sn].ss[SU], source[si->sn].ss[SV], du2, dv2); |
| 439 |
} |
| 440 |
|
| 441 |
|
| 442 |
double |
| 443 |
scylform( /* compute cosine for cylinder's projection */ |
| 444 |
int sn, |
| 445 |
FVECT dir /* assume normalized */ |
| 446 |
) |
| 447 |
{ |
| 448 |
RREAL *dv; |
| 449 |
double d; |
| 450 |
|
| 451 |
dv = source[sn].ss[SU]; |
| 452 |
d = DOT(dir, dv); |
| 453 |
d *= d / DOT(dv,dv); |
| 454 |
return(sqrt(1. - d)); |
| 455 |
} |
