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/* Copyright (c) 1998 Silicon Graphics, Inc. */ |
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|
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#ifndef lint |
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static char SCCSid[] = "$SunId$ SGI"; |
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#endif |
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|
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/* |
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* Holodeck beam tracking for display process |
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*/ |
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|
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#include "rholo.h" |
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#include "rhdisp.h" |
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#include "rhdriver.h" |
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#include "random.h" |
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|
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#ifndef MAXDIST |
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#define MAXDIST 42 /* maximum distance outside section */ |
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#endif |
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#ifndef NVSAMPS |
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#define NVSAMPS 16384 /* number of ray samples per view */ |
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#endif |
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#ifndef MEYERNG |
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#define MEYERNG 0.1 /* target mean eye range (rel. to grid) */ |
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#endif |
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#ifndef MAXTODO |
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#define MAXTODO 3 /* maximum sections to look at */ |
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#endif |
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#ifndef MAXDRAT |
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#define MAXDRAT 3.0 /* maximum distance ratio btwn. cand. sect. */ |
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#endif |
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|
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#define CBEAMBLK 1024 /* cbeam allocation block size */ |
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|
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static struct beamcomp { |
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int hd; /* holodeck section number */ |
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int bi; /* beam index */ |
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int4 nr; /* number of samples desired */ |
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} *cbeam = NULL; /* current beam list */ |
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|
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VIEWPOINT cureye; /* current eye position */ |
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|
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static int ncbeams = 0; /* number of sorted beams in cbeam */ |
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static int xcbeams = 0; /* extra (unregistered) beams past ncbeams */ |
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static int maxcbeam = 0; /* size of cbeam array */ |
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|
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|
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int |
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newcbeam() /* allocate new entry at end of cbeam array */ |
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{ |
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int i; |
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|
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if ((i = ncbeams + xcbeams++) >= maxcbeam) { /* grow array */ |
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maxcbeam += CBEAMBLK; |
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if (cbeam == NULL) |
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cbeam = (struct beamcomp *)malloc( |
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maxcbeam*sizeof(struct beamcomp) ); |
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else |
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cbeam = (struct beamcomp *)realloc( (char *)cbeam, |
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maxcbeam*sizeof(struct beamcomp) ); |
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if (cbeam == NULL) |
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error(SYSTEM, "out of memory in newcbeam"); |
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} |
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return(i); |
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} |
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|
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|
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int |
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cbeamcmp(cb1, cb2) /* compare two cbeam entries for sort: keep orphans */ |
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register struct beamcomp *cb1, *cb2; |
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{ |
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register int c; |
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|
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if ((c = cb1->bi - cb2->bi)) /* sort on beam index first */ |
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return(c); |
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return(cb1->hd - cb2->hd); /* use hd to resolve matches */ |
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} |
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|
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|
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int |
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cbeamcmp2(cb1, cb2) /* compare two cbeam entries for sort: no orphans */ |
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register struct beamcomp *cb1, *cb2; |
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{ |
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register int c; |
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|
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if (!cb1->nr) /* put orphans at the end, unsorted */ |
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return(cb2->nr); |
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if (!cb2->nr) |
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return(-1); |
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if ((c = cb1->bi - cb2->bi)) /* sort on beam index first */ |
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return(c); |
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return(cb1->hd - cb2->hd); /* use hd to resolve matches */ |
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} |
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|
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|
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int |
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findcbeam(hd, bi) /* find the specified beam in our sorted list */ |
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int hd, bi; |
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{ |
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struct beamcomp cb; |
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register struct beamcomp *p; |
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|
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if (ncbeams <= 0) |
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return(-1); |
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cb.hd = hd; cb.bi = bi; cb.nr = 0; |
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p = (struct beamcomp *)bsearch((char *)&cb, (char *)cbeam, ncbeams, |
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sizeof(struct beamcomp), cbeamcmp); |
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if (p == NULL) |
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return(-1); |
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return(p - cbeam); |
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} |
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|
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|
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int |
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getcbeam(hd, bi) /* get the specified beam, allocating as necessary */ |
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register int hd; |
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int bi; |
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{ |
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register int n; |
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/* first, look in sorted list */ |
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if ((n = findcbeam(hd, bi)) >= 0) |
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return(n); |
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/* linear search through xcbeams to be sure */ |
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for (n = ncbeams+xcbeams; n-- > ncbeams; ) |
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if (cbeam[n].bi == bi && cbeam[n].hd == hd) |
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return(n); |
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/* check legality */ |
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if (hd < 0 | hd >= HDMAX || hdlist[hd] == NULL) |
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error(INTERNAL, "illegal holodeck number in getcbeam"); |
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if (bi < 1 | bi > nbeams(hdlist[hd])) |
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error(INTERNAL, "illegal beam index in getcbeam"); |
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n = newcbeam(); /* allocate and assign */ |
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cbeam[n].nr = 0; cbeam[n].hd = hd; cbeam[n].bi = bi; |
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return(n); |
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} |
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|
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|
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cbeamsort(adopt) /* sort our beam list, possibly turning out orphans */ |
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int adopt; |
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{ |
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register int i; |
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|
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if (!(ncbeams += xcbeams)) |
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return; |
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xcbeams = 0; |
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qsort((char *)cbeam, ncbeams, sizeof(struct beamcomp), |
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adopt ? cbeamcmp : cbeamcmp2); |
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if (adopt) |
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return; |
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for (i = ncbeams; i--; ) /* identify orphans */ |
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if (cbeam[i].nr) |
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break; |
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xcbeams = ncbeams - ++i; /* put orphans after ncbeams */ |
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ncbeams = i; |
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} |
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|
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|
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cbeamop(op, bl, n) /* update beams on server list */ |
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int op; |
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register struct beamcomp *bl; |
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int n; |
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{ |
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register PACKHEAD *pa; |
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register int i; |
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|
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if (n <= 0) |
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return; |
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pa = (PACKHEAD *)malloc(n*sizeof(PACKHEAD)); |
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if (pa == NULL) |
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error(SYSTEM, "out of memory in cbeamop"); |
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for (i = 0; i < n; i++) { |
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pa[i].hd = bl[i].hd; |
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pa[i].bi = bl[i].bi; |
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pa[i].nr = bl[i].nr; |
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pa[i].nc = 0; |
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} |
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serv_request(op, n*sizeof(PACKHEAD), (char *)pa); |
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free((char *)pa); |
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} |
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|
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|
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static int |
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comptodo(tdl, vw) /* compute holodeck sections in view */ |
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int tdl[MAXTODO+1]; |
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VIEW *vw; |
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{ |
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int n = 0; |
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FVECT gp, dv; |
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double dist2[MAXTODO+1], thisdist2; |
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register int i, j; |
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/* find closest MAXTODO sections */ |
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for (i = 0; hdlist[i]; i++) { |
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hdgrid(gp, hdlist[i], vw->vp); |
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for (j = 0; j < 3; j++) |
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if (gp[j] < 0.) |
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dv[j] = -gp[j]; |
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else if (gp[j] > hdlist[i]->grid[j]) |
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dv[j] = gp[j] - hdlist[i]->grid[j]; |
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else |
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dv[j] = 0.; |
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thisdist2 = DOT(dv,dv); |
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for (j = n; j > 0 && thisdist2 < dist2[j-1]; j--) { |
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tdl[j] = tdl[j-1]; |
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dist2[j] = dist2[j-1]; |
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} |
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tdl[j] = i; |
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dist2[j] = thisdist2; |
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if (n < MAXTODO) |
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n++; |
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} |
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/* watch for bad move */ |
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if (n && dist2[0] > MAXDIST*MAXDIST) { |
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error(COMMAND, "move past outer limits"); |
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return(0); |
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} |
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/* avoid big differences */ |
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for (j = 1; j < n; j++) |
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if (dist2[j] > MAXDRAT*MAXDRAT*dist2[j-1]) |
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n = j; |
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tdl[n] = -1; |
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return(n); |
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} |
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|
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|
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int |
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addview(hd, vw, hres, vres) /* add view for section */ |
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int hd; |
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VIEW *vw; |
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int hres, vres; |
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{ |
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int sampquant, samptot = 0; |
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int h, v, shr, svr; |
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GCOORD gc[2]; |
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FVECT rorg, rdir; |
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/* compute sampling grid */ |
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if (hres|vres && hres*vres <= NVSAMPS) { |
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shr = hres; svr = vres; |
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sampquant = 1; |
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} else { |
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shr = sqrt(NVSAMPS/viewaspect(vw)) + .5; |
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svr = (NVSAMPS + shr/2)/shr; |
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sampquant = (hres*vres + shr*svr/2)/(shr*svr); |
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} |
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/* intersect sample rays with section */ |
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for (v = svr; v--; ) |
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for (h = shr; h--; ) { |
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if (viewray(rorg, rdir, vw, (v+frandom())/svr, |
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(h+frandom())/shr) < -FTINY) |
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continue; |
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if (hdinter(gc, NULL, NULL, hdlist[hd], rorg, rdir) |
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>= FHUGE) |
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continue; |
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cbeam[getcbeam(hd,hdbindex(hdlist[hd],gc))].nr += |
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sampquant; |
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samptot += sampquant; |
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} |
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return(samptot); |
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} |
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|
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|
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beam_init(fresh) /* clear beam list for new view(s) */ |
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int fresh; |
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{ |
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register int i; |
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|
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if (fresh) /* discard old beams? */ |
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ncbeams = xcbeams = 0; |
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else /* else clear sample requests */ |
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for (i = ncbeams+xcbeams; i--; ) |
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cbeam[i].nr = 0; |
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cureye.rng = 0.; |
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} |
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|
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|
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int * |
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beam_view(vn, hr, vr) /* add beam view (if advisable) */ |
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VIEW *vn; |
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int hr, vr; |
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{ |
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static int todo[MAXTODO+1]; |
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int n; |
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double hdgsiz, d; |
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register HOLO *hp; |
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register int i; |
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/* find nearby sections */ |
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if (!(n = comptodo(todo, vn))) |
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return(NULL); |
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/* sort our list */ |
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cbeamsort(1); |
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/* add view to flagged sections */ |
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for (i = 0; i < n; i++) |
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if (!addview(todo[i], vn, hr, vr)) { /* whoops! */ |
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register int j; |
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n--; /* delete from list */ |
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for (j = i--; j <= n; j++) |
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todo[j] = todo[j+1]; |
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} |
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if (!n || MEYERNG <= FTINY || vn->type == VT_PAR) |
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return(todo); |
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hdgsiz = 0.; /* compute mean grid size */ |
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for (i = 0; i < n; i++) { |
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hp = hdlist[todo[i]]; |
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hdgsiz += 1./3. / VLEN(hp->wg[0]) + |
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1./3. / VLEN(hp->wg[1]) + |
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1./3. / VLEN(hp->wg[2]) ; |
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} |
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hdgsiz /= (double)n; |
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/* add to current eye position */ |
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if (cureye.rng <= FTINY) { |
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VCOPY(cureye.vpt, vn->vp); |
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cureye.rng = MEYERNG * hdgsiz; |
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} else if ((d = sqrt(dist2(vn->vp,cureye.vpt))) + MEYERNG*hdgsiz > |
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cureye.rng) { |
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for (i = 3; i--; ) |
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cureye.vpt[i] = 0.5*(cureye.vpt[i] + vn->vp[i]); |
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cureye.rng = 0.5*(cureye.rng + MEYERNG*hdgsiz + d); |
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} |
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return(todo); |
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} |
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|
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|
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int |
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beam_sync(all) /* update beam list on server */ |
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int all; |
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{ |
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/* set new eye position */ |
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serv_request(DR_VIEWPOINT, sizeof(VIEWPOINT), (char *)&cureye); |
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/* sort list (put orphans at end) */ |
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cbeamsort(all < 0); |
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/* send beam request */ |
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if (all) |
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cbeamop(DR_NEWSET, cbeam, ncbeams); |
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else |
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cbeamop(DR_ADJSET, cbeam, ncbeams+xcbeams); |
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xcbeams = 0; /* truncate our list */ |
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return(ncbeams); |
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} |
