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/* Copyright (c) 1986 Regents of the University of California */
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#ifndef lint
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static char SCCSid[] = "$SunId$ LBL";
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#endif
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/*
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* octree.c - routines dealing with octrees and cubes.
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*
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* 7/28/85
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*/
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#include "standard.h"
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#include "octree.h"
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OCTREE *octblock[MAXOBLK]; /* our octree */
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static OCTREE ofreelist = EMPTY; /* freed octree nodes */
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static OCTREE treetop = 0; /* next free node */
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OCTREE
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octalloc() /* allocate an octree */
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{
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register OCTREE freet;
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if ((freet = ofreelist) != EMPTY) {
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ofreelist = octkid(freet, 0);
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return(freet);
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}
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freet = treetop;
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if (octti(freet) == 0) {
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errno = 0;
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if (octbi(freet) >= MAXOBLK)
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return(EMPTY);
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if ((octblock[octbi(freet)] = (OCTREE *)bmalloc(
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(unsigned)256*8*sizeof(OCTREE))) == NULL)
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return(EMPTY);
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}
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treetop += 8;
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return(freet);
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}
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octfree(ot) /* free an octree */
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register OCTREE ot;
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{
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register int i;
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if (!istree(ot))
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return;
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for (i = 0; i < 8; i++)
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octfree(octkid(ot, i));
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octkid(ot, 0) = ofreelist;
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ofreelist = ot;
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}
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octdone() /* free EVERYTHING */
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{
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register int i;
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for (i = 0; i < MAXOBLK; i++) {
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bfree((char *)octblock[i], (unsigned)256*8*sizeof(OCTREE));
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octblock[i] = NULL;
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}
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ofreelist = EMPTY;
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treetop = 0;
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}
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OCTREE
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combine(ot) /* recursively combine nodes */
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register OCTREE ot;
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{
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register int i;
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register OCTREE ores;
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if (!istree(ot)) /* not a tree */
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return(ot);
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ores = octkid(ot, 0) = combine(octkid(ot, 0));
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for (i = 1; i < 8; i++)
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if ((octkid(ot, i) = combine(octkid(ot, i))) != ores)
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ores = ot;
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if (!istree(ores)) { /* all were identical leaves */
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octkid(ot, 0) = ofreelist;
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ofreelist = ot;
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}
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return(ores);
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}
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culocate(cu, pt) /* locate point within cube */
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register CUBE *cu;
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register FVECT pt;
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{
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register int i;
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int branch;
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while (istree(cu->cutree)) {
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cu->cusize *= 0.5;
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branch = 0;
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for (i = 0; i < 3; i++)
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if (cu->cuorg[i] + cu->cusize <= pt[i]) {
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cu->cuorg[i] += cu->cusize;
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branch |= 1 << i;
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}
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cu->cutree = octkid(cu->cutree, branch);
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}
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}
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cucopy(cu1, cu2) /* copy cu2 into cu1 */
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register CUBE *cu1, *cu2;
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{
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cu1->cutree = cu2->cutree;
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cu1->cusize = cu2->cusize;
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VCOPY(cu1->cuorg, cu2->cuorg);
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}
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incube(cu, pt) /* determine if a point is inside a cube */
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register CUBE *cu;
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register FVECT pt;
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{
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if (cu->cuorg[0] > pt[0] || pt[0] >= cu->cuorg[0] + cu->cusize)
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return(0);
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if (cu->cuorg[1] > pt[1] || pt[1] >= cu->cuorg[1] + cu->cusize)
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return(0);
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if (cu->cuorg[2] > pt[2] || pt[2] >= cu->cuorg[2] + cu->cusize)
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return(0);
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return(1);
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}
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