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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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|
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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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|
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#define MAXVOXEL 16 /* maximum number of active voxels */ |
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|
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typedef struct { |
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int hd; /* holodeck section number (-1 if inactive) */ |
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int i[3]; /* voxel index (may be outside section) */ |
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} VOXL; /* a voxel */ |
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|
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static VOXL voxel[MAXVOXEL] = {{-1}}; /* current voxel list */ |
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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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unsigned int2 wants; /* flags telling which voxels want us */ |
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unsigned int2 hd; /* holodeck section number */ |
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int4 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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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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struct cellact { |
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short vi; /* voxel index */ |
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short add; /* zero means delete */ |
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short rev; /* reverse ray direction? */ |
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VIEW *vp; /* view for image */ |
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short hr, vr; /* image resolution */ |
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}; /* action for cell */ |
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|
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struct beamact { |
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struct cellact ca; /* cell action */ |
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GCOORD gc; /* grid coordinate */ |
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}; /* beam origin and action */ |
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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->wants) /* put orphans at the end, unsorted */ |
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return(cb2->wants); |
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if (!cb2->wants) |
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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.wants = 0; 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].wants = 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].wants) |
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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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add_voxels(vp) /* add voxels corresponding to view point */ |
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FVECT vp; |
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{ |
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int first, n, rfl = 0; |
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FVECT gp; |
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double d; |
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int dist, bestd = 0x7fff; |
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VOXL vox; |
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register int i, j, k; |
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/* count voxels in list already */ |
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for (first = 0; first < MAXVOXEL && voxel[first].hd >= 0; first++) |
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; |
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/* find closest voxels */ |
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for (n = first, i = 0; n < MAXVOXEL && hdlist[i]; i++) { |
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hdgrid(gp, hdlist[i], vp); |
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for (j = 0; n < MAXVOXEL && j < 8; j++) { |
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dist = 0; |
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for (k = 0; k < 3; k++) { |
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d = gp[k] - .5 + (j>>k & 1); |
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if (d < 0.) |
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dist += -(vox.i[k] = (int)d - 1); |
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else if ((vox.i[k] = d) >= hdlist[i]->grid[k]) |
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dist += vox.i[k] - |
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hdlist[i]->grid[k] + 1; |
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} |
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if (dist > bestd) /* others were closer */ |
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continue; |
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if (dist < bestd) { /* start closer list */ |
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n = first; |
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bestd = dist; |
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rfl = 0; |
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} |
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/* check if already in list */ |
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for (k = first; k--; ) |
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if (voxel[k].hd == i && |
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voxel[k].i[0] == vox.i[0] && |
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voxel[k].i[1] == vox.i[1] && |
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voxel[k].i[2] == vox.i[2]) |
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break; |
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if (k >= 0) { |
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rfl |= 1<<k; |
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continue; |
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} |
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vox.hd = i; /* add this voxel */ |
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copystruct(&voxel[n], &vox); |
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rfl |= 1<<n++; |
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} |
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} |
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/* check for really stupid move */ |
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if (bestd > 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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if (n < MAXVOXEL) |
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voxel[n].hd = -1; |
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return(rfl); |
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} |
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|
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|
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int |
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dobeam(gcp, bp) /* express interest or disintrest in a beam */ |
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GCOORD *gcp; |
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register struct beamact *bp; |
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{ |
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GCOORD gc[2]; |
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int bi, i, n; |
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/* compute beam index */ |
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if (bp->ca.rev) { |
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copystruct(gc, &bp->gc); |
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copystruct(gc+1, gcp); |
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} else { |
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copystruct(gc, gcp); |
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copystruct(gc+1, &bp->gc); |
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} |
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if ((bi = hdbindex(hdlist[voxel[bp->ca.vi].hd], gc)) <= 0) |
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error(CONSISTENCY, "bad grid coordinate in dobeam"); |
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if (bp->ca.add) { /* add it in */ |
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i = getcbeam(voxel[bp->ca.vi].hd, bi); |
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cbeam[i].wants |= 1<<bp->ca.vi; /* say we want it */ |
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n = npixels(bp->ca.vp, bp->ca.hr, bp->ca.vr, |
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hdlist[cbeam[i].hd], cbeam[i].bi); |
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if (n > cbeam[i].nr) |
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cbeam[i].nr = n; |
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return(i == ncbeams+xcbeams-1); /* return 1 if totally new */ |
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} |
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/* else delete it */ |
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i = findcbeam(voxel[bp->ca.vi].hd, bi); |
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if (i >= 0 && cbeam[i].wants & 1<<bp->ca.vi) { |
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cbeam[i].wants &= ~(1<<bp->ca.vi); /* we don't want it */ |
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if (!cbeam[i].wants) |
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cbeam[i].nr = 0; |
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return(1); /* indicate change */ |
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} |
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return(0); |
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} |
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|
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|
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|
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int |
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docell(gcp, cap) /* find beams corresponding to cell and voxel */ |
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GCOORD *gcp; |
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register struct cellact *cap; |
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{ |
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register HOLO *hp = hdlist[voxel[cap->vi].hd]; |
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FVECT org, dir[4]; |
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FVECT vgp, cgp, vc; |
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FVECT v1, v2; |
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struct beamact bo; |
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int axmax, j; |
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double d, avmax; |
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register int i; |
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/* compute cell center */ |
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cgp[gcp->w>>1] = gcp->w&1 ? hp->grid[gcp->w>>1] : 0 ; |
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cgp[hdwg0[gcp->w]] = gcp->i[0] + .5; |
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cgp[hdwg1[gcp->w]] = gcp->i[1] + .5; |
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hdworld(org, hp, cgp); |
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/* compute direction to voxel center */ |
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for (i = 3; i--; ) |
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vgp[i] = voxel[cap->vi].i[i] + .5; |
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hdworld(vc, hp, vgp); |
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for (i = 3; i--; ) |
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vc[i] -= org[i]; |
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/* compute maximum area axis */ |
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axmax = -1; avmax = 0; |
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for (i = 3; i--; ) { |
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d = vgp[i] - cgp[i]; |
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if (d < 0.) d = -d; |
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if (d > avmax) { |
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avmax = d; |
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axmax = i; |
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} |
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} |
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#ifdef DEBUG |
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if (axmax < 0.) |
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error(CONSISTENCY, "botched axis computation in docell"); |
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#endif |
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/* compute offset vectors */ |
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d = 0.5/hp->grid[j=(axmax+1)%3]; |
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for (i = 3; i--; ) |
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v1[i] = hp->xv[j][i] * d; |
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d = 0.5/hp->grid[j=(axmax+2)%3]; |
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if (DOT(hp->wg[axmax], vc) < 0.) |
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d = -d; /* reverse vertex order */ |
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for (i = 3; i--; ) |
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v2[i] = hp->xv[j][i] * d; |
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/* compute voxel pyramid */ |
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for (i = 3; i--; ) { |
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dir[0][i] = vc[i] - v1[i] - v2[i]; |
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dir[1][i] = vc[i] + v1[i] - v2[i]; |
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dir[2][i] = vc[i] + v1[i] + v2[i]; |
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dir[3][i] = vc[i] - v1[i] + v2[i]; |
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} |
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/* visit beams for opposite cells */ |
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copystruct(&bo.ca, cap); |
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copystruct(&bo.gc, gcp); |
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return(visit_cells(org, dir, hp, dobeam, &bo)); |
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} |
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|
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|
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int |
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doview(cap) /* visit cells for a given view */ |
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struct cellact *cap; |
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{ |
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int orient; |
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FVECT org, dir[4]; |
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/* compute view pyramid */ |
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orient = viewpyramid(org, dir, hdlist[voxel[cap->vi].hd], cap->vp); |
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if (!orient) |
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error(INTERNAL, "unusable view in doview"); |
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cap->rev = orient < 0; |
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/* visit cells within pyramid */ |
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return(visit_cells(org, dir, hdlist[voxel[cap->vi].hd], docell, cap)); |
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} |
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|
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|
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beam_init() /* clear beam list for new view(s) */ |
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{ |
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register int i; |
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/* clear desire flags */ |
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for (i = ncbeams+xcbeams; i--; ) |
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cbeam[i].wants = cbeam[i].nr = 0; |
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voxel[0].hd = -1; /* clear voxel list */ |
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} |
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|
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|
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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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struct cellact ca; |
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int vfl; |
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/* sort our list */ |
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cbeamsort(1); |
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/* add new voxels */ |
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vfl = add_voxels(vn->vp); |
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if (!vfl) |
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return(0); |
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ca.vp = vn; ca.hr = hr; ca.vr = vr; |
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ca.add = 1; /* update our beam list */ |
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for (ca.vi = 0; vfl; vfl >>= 1, ca.vi++) |
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if (vfl & 1) |
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doview(&ca); |
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return(1); |
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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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/* sort list to put orphans at end */ |
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cbeamsort(0); |
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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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} |
