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#ifndef lint |
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static const char RCSid[] = "$Id: octree.c,v 2.7 2007/05/23 21:39:38 greg Exp $"; |
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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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|
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#include "copyright.h" |
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|
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#include "standard.h" |
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|
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#include "octree.h" |
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|
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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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|
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|
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OCTREE |
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octalloc() /* allocate an octree */ |
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{ |
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OCTREE freet; |
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|
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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 *)malloc( |
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(unsigned)OCTBLKSIZ*8*sizeof(OCTREE))) == NULL) |
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return(EMPTY); |
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} |
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treetop++; |
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return(freet); |
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} |
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|
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|
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void |
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octfree(ot) /* free an octree */ |
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OCTREE ot; |
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{ |
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int i; |
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|
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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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|
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|
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void |
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octdone() /* free EVERYTHING */ |
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{ |
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int i; |
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|
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for (i = 0; i < MAXOBLK; i++) { |
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if (octblock[i] == NULL) |
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break; |
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free((void *)octblock[i]); |
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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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|
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|
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OCTREE |
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combine(ot) /* recursively combine nodes */ |
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OCTREE ot; |
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{ |
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int i; |
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OCTREE ores; |
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|
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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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|
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|
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void |
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culocate(cu, pt) /* locate point within cube */ |
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CUBE *cu; |
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FVECT pt; |
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{ |
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int i; |
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int branch; |
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|
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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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|
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|
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int |
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incube(cu, pt) /* determine if a point is inside a cube */ |
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CUBE *cu; |
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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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} |
