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#ifndef lint |
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static const char RCSid[] = "$Id: viewbeams.c,v 3.3 2003/04/23 00:52:34 greg Exp $"; |
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#endif |
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/* |
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* Convert view to beam list. |
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*/ |
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|
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#include "rholo.h" |
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#include "view.h" |
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#include "random.h" |
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|
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#ifndef MINRES |
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#define MINRES 12 /* section sample resolution */ |
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#endif |
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#ifndef NVSAMPS |
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#define NVSAMPS 16384 /* target number of view samples */ |
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#endif |
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|
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#define OJITTER 0.25 /* amount to jitter sample origin */ |
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|
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#define BALLOCBLK 128 /* beam allocation block size */ |
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|
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|
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static BEAMLIST blist; |
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|
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|
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static |
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add2blist(hd, bi, nr) /* add to beam sample list */ |
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int hd, bi, nr; |
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{ |
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register int i; |
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|
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for (i = blist.nb; i--; ) |
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if (blist.bl[i].bi == bi && blist.bl[i].hd == hd) { |
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blist.bl[i].nr += nr; /* found it */ |
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return; |
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} |
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i = blist.nb++; /* else add beam to list */ |
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if (i % BALLOCBLK == 0) { |
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blist.bl = (PACKHEAD *)realloc((void *)blist.bl, |
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(i+BALLOCBLK)*sizeof(PACKHEAD)); |
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CHECK(blist.bl==NULL, SYSTEM, "out of memory in add2blist"); |
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} |
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blist.bl[i].hd = hd; blist.bl[i].bi = bi; |
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blist.bl[i].nr = nr; blist.bl[i].nc = 0; |
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} |
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|
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|
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int16 * |
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viewbeams(vp, hr, vr, blp) /* convert view into sections/beams */ |
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VIEW *vp; |
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int hr, vr; |
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BEAMLIST *blp; |
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{ |
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static int16 sectlist[HDMAX+1]; |
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int16 sectarr[MINRES+1][MINRES+1]; |
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double d0, d1, mindist; |
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GCOORD gc[2]; |
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FVECT rorg, rdir; |
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int shr, svr, sampquant; |
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int v; |
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register int h, hd; |
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/* clear section flags */ |
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bzero((char *)sectlist, sizeof(sectlist)); |
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/* identify view sections */ |
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for (v = 0; v <= MINRES; v++) |
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for (h = 0; h <= MINRES; h++) { |
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sectarr[v][h] = -1; |
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mindist = 0.99*FHUGE; |
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if (viewray(rorg, rdir, vp, (double)h/MINRES, |
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(double)v/MINRES) < -FTINY) |
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continue; |
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for (hd = 0; hdlist[hd] != NULL; hd++) { |
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d0 = hdinter(gc, NULL, &d1, |
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hdlist[hd], rorg, rdir); |
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if (d0 >= 0.99*FHUGE) |
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continue; /* missed */ |
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if (d0 <= 0. && d1 >= 0.) { |
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sectarr[v][h] = hd; |
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break; /* inside */ |
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} |
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if (d0 > 0. && d0 < mindist) { |
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sectarr[v][h] = hd; |
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mindist = d0; |
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} else if (d1 < 0. && -d1 < mindist) { |
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sectarr[v][h] = hd; |
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mindist = -d1; |
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} |
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} |
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if ((hd = sectarr[v][h]) >= 0) |
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sectlist[hd]++; /* flag section */ |
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} |
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/* convert flags to list */ |
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for (h = hd = 0; hdlist[hd] != NULL; h++, hd++) { |
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while (!sectlist[hd]) |
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if (hdlist[++hd] == NULL) |
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goto loopexit; |
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sectlist[h] = hd; |
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} |
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loopexit: |
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sectlist[h] = -1; /* list terminator */ |
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if (blp == NULL) /* if no beam list... */ |
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return(sectlist); /* return early */ |
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/* else set up sampling */ |
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if (hr|vr && hr*vr <= NVSAMPS) { |
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shr = hr; svr = vr; |
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sampquant = 1; |
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} else { |
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shr = sqrt(NVSAMPS/viewaspect(vp)) + .5; |
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svr = (NVSAMPS + shr/2)/shr; |
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sampquant = (hr*vr + shr*svr/2)/(shr*svr); |
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} |
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blist.bl = NULL; blist.nb = 0; /* sample view rays */ |
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for (v = svr; v--; ) |
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for (h = shr; h--; ) { |
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hd = random()>>6 & 03; /* get section */ |
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hd = sectarr[v*MINRES/svr + (hd&01)] |
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[h*MINRES/shr + (hd>>1)]; |
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if (hd < 0) |
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continue; |
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/* get sample ray */ |
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if (viewray(rorg, rdir, vp, (h+frandom())/shr, |
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(v+frandom())/svr) < -FTINY) |
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continue; |
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#ifdef OJITTER |
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/* jitter origin */ |
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d0 = OJITTER*(frandom() - .5) / hdlist[hd]->grid[0]; |
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VSUM(rorg, rorg, hdlist[hd]->xv[0], d0); |
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d0 = OJITTER*(frandom() - .5) / hdlist[hd]->grid[1]; |
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VSUM(rorg, rorg, hdlist[hd]->xv[1], d0); |
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d0 = OJITTER*(frandom() - .5) / hdlist[hd]->grid[2]; |
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VSUM(rorg, rorg, hdlist[hd]->xv[2], d0); |
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#endif |
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/* intersect section */ |
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if (hdinter(gc, NULL, NULL, hdlist[hd], rorg, rdir) |
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>= 0.99*FHUGE) |
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continue; |
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/* add samples */ |
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add2blist(hd, hdbindex(hdlist[hd],gc), sampquant); |
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} |
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copystruct(blp, &blist); /* transfer beam list */ |
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return(sectlist); /* all done! */ |
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} |
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|
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|
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int |
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nextview(vp, fp) /* get next view from fp */ |
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VIEW *vp; |
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FILE *fp; |
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{ |
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char linebuf[256]; |
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|
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while (fgets(linebuf, sizeof(linebuf), fp) != NULL) |
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if (isview(linebuf) && sscanview(vp, linebuf) > 0) |
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return(0); |
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return(EOF); |
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} |
