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rhd_qtree.c

#ifndef lint
static const char RCSid[] = "$Id: rhd_qtree.c,v 3.26 2005/01/07 20:33:02 greg Exp $";
#endif
/*
 * Quadtree driver support routines.
 */

#include <string.h>

#include "standard.h"
#include "rhd_qtree.h"
                        /* quantity of leaves to free at a time */
#ifndef LFREEPCT
#define     LFREEPCT    25
#endif
                        /* maximum allowed angle difference (deg.) */
#ifndef MAXANG
#define MAXANG          20
#endif
#if MAXANG>0
#define MAXDIFF2  ( MAXANG*MAXANG * (PI*PI/180./180.))
#endif

#define abs(i)          ((i) < 0 ? -(i) : (i))

RTREE qtrunk;                 /* our quadtree trunk */
double      qtDepthEps = .05; /* epsilon to compare depths (z fraction) */
int   qtMinNodesiz = 2; /* minimum node dimension (pixels) */
struct rleaves    qtL;        /* our pile of leaves */

int   rayqleft = 0;           /* rays left to queue before flush */

static int32      falleaves;  /* our list of fallen leaves */

#define composted(li)   (qtL.bl <= qtL.tl ? \
                              ((li) < qtL.bl || (li) >= qtL.tl) : \
                              ((li) < qtL.bl && (li) >= qtL.tl))

#define     TBUNDLESIZ  409   /* number of twigs in a bundle */

static RTREE      **twigbundle;     /* free twig blocks (NULL term.) */
static int  nexttwig;   /* next free twig */

static RTREE *newtwig(void);
static void qtFreeTree(int really);
static void shaketree(RTREE *tp);
static int putleaf(int li, int drop);


static RTREE *
newtwig(void)                 /* allocate a twig */
{
      register int      bi;

      if (twigbundle == NULL) {     /* initialize */
            twigbundle = (RTREE **)malloc(sizeof(RTREE *));
            if (twigbundle == NULL)
                  goto memerr;
            twigbundle[0] = NULL;
      }
      bi = nexttwig / TBUNDLESIZ;
      if (twigbundle[bi] == NULL) { /* new block */
            twigbundle = (RTREE **)realloc((void *)twigbundle,
                              (bi+2)*sizeof(RTREE *));
            if (twigbundle == NULL)
                  goto memerr;
            twigbundle[bi] = (RTREE *)calloc(TBUNDLESIZ, sizeof(RTREE));
            if (twigbundle[bi] == NULL)
                  goto memerr;
            twigbundle[bi+1] = NULL;
      }
                        /* nexttwig++ % TBUNDLESIZ */
      return(twigbundle[bi] + (nexttwig++ - bi*TBUNDLESIZ));
memerr:
      error(SYSTEM, "out of memory in newtwig");
      return NULL; /* pro forma return */
}


static void
qtFreeTree(       /* free allocated twigs */
      int   really
)
{
      register int      i;

      qtrunk.flgs = CH_ANY;   /* chop down tree */
      if (twigbundle == NULL)
            return;
      i = (TBUNDLESIZ-1+nexttwig)/TBUNDLESIZ;
      nexttwig = 0;
      if (!really) {          /* just clear allocated blocks */
            while (i--)
                  memset((char *)twigbundle[i], '\0', TBUNDLESIZ*sizeof(RTREE));
            return;
      }
                        /* else "really" means free up memory */
      for (i = 0; twigbundle[i] != NULL; i++)
            free((void *)twigbundle[i]);
      free((void *)twigbundle);
      twigbundle = NULL;
}


#define     LEAFSIZ           (3*sizeof(float)+sizeof(int32)+\
                  sizeof(TMbright)+6*sizeof(BYTE))

extern int
qtAllocLeaves(          /* allocate space for n leaves */
      register int      n
)
{
      unsigned    nbytes;
      register unsigned i;

      qtFreeTree(0);          /* make sure tree is empty */
      if (n <= 0)
            return(0);
      if (qtL.nl >= n)
            return(qtL.nl);
      else if (qtL.nl > 0)
            free(qtL.base);
                        /* round space up to nearest power of 2 */
      nbytes = n*LEAFSIZ + 8;
      for (i = 1024; nbytes > i; i <<= 1)
            ;
      n = (i - 8) / LEAFSIZ;  /* should we make sure n is even? */
      qtL.base = (char *)malloc(n*LEAFSIZ);
      if (qtL.base == NULL)
            return(0);
                        /* assign larger alignment types earlier */
      qtL.wp = (float (*)[3])qtL.base;
      qtL.wd = (int32 *)(qtL.wp + n);
      qtL.brt = (TMbright *)(qtL.wd + n);
      qtL.chr = (BYTE (*)[3])(qtL.brt + n);
      qtL.rgb = (BYTE (*)[3])(qtL.chr + n);
      qtL.nl = n;
      qtL.tml = qtL.bl = qtL.tl = 0;
      falleaves = -1;
      return(n);
}

#undef      LEAFSIZ


extern void
qtFreeLeaves(void)                  /* free our allocated leaves and twigs */
{
      qtFreeTree(1);          /* free tree also */
      if (qtL.nl <= 0)
            return;
      free(qtL.base);
      qtL.base = NULL;
      qtL.nl = 0;
}


static void
shaketree(              /* shake dead leaves from tree */
      register RTREE    *tp
)
{
      register int      i, li;

      for (i = 0; i < 4; i++)
            if (tp->flgs & BRF(i)) {
                  shaketree(tp->k[i].b);
                  if (is_stump(tp->k[i].b))
                        tp->flgs &= ~BRF(i);
            } else if (tp->flgs & LFF(i)) {
                  li = tp->k[i].li;
                  if (composted(li))
                        tp->flgs &= ~LFF(i);
            }
}


extern int
qtCompost(              /* free up some leaves */
      int   pct
)
{
      register int32    *fl;
      int   nused, nclear, nmapped;
                        /* figure out how many leaves to clear */
      nclear = qtL.nl * pct / 100;
      nused = qtL.tl - qtL.bl;
      if (nused <= 0) nused += qtL.nl;
      nclear -= qtL.nl - nused;
      if (nclear <= 0)
            return(0);
      if (nclear >= nused) {  /* clear them all */
            qtFreeTree(0);
            qtL.tml = qtL.bl = qtL.tl = 0;
            falleaves = -1;
            return(nused);
      }
                        /* else clear leaves from bottom */
      nmapped = qtL.tml - qtL.bl;
      if (nmapped < 0) nmapped += qtL.nl;
      qtL.bl += nclear;
      if (qtL.bl >= qtL.nl) qtL.bl -= qtL.nl;
      if (nmapped <= nclear) qtL.tml = qtL.bl;
      shaketree(&qtrunk);     /* dereference composted leaves */
      for (fl = &falleaves; *fl >= 0; fl = qtL.wd + *fl)
            while (composted(*fl))
                  if ((*fl = qtL.wd[*fl]) < 0)
                        return(nclear);
      return(nclear);
}


extern int
qtFindLeaf(       /* find closest leaf to (x,y) */
      int   x,
      int   y
)
{
      register RTREE    *tp = &qtrunk;
      int   li = -1;
      int   x0=0, y0=0, x1=odev.hres, y1=odev.vres;
      int   mx, my;
      register int      q;
                              /* check limits */
      if (x < 0 || x >= odev.hres || y < 0 || y >= odev.vres)
            return(-1);
                              /* find nearby leaf in our tree */
      for ( ; ; ) {
            for (q = 0; q < 4; q++)       /* find any leaf this level */
                  if (tp->flgs & LFF(q)) {
                        li = tp->k[q].li;
                        break;
                  }
            q = 0;                        /* which quadrant are we? */
            mx = (x0 + x1) >> 1;
            my = (y0 + y1) >> 1;
            if (x < mx) x1 = mx;
            else {x0 = mx; q |= 01;}
            if (y < my) y1 = my;
            else {y0 = my; q |= 02;}
            if (tp->flgs & BRF(q)) {      /* branch down if not a leaf */
                  tp = tp->k[q].b;
                  continue;
            }
            if (tp->flgs & LFF(q))        /* good shot! */
                  return(tp->k[q].li);
            return(li);             /* else return what we have */
      }
}


static int
putleaf(          /* put a leaf in our tree */
      register int      li,
      int   drop
)
{
      register RTREE    *tp = &qtrunk;
      int   x0=0, y0=0, x1=odev.hres, y1=odev.vres;
      register int      lo = -1;
      double      d2;
      int   x, y, mx, my;
      double      z;
      FVECT ip, wp, vd;
      register int      q;
                              /* check for dead leaf */
      if (!qtL.chr[li][1] && !(qtL.chr[li][0] | qtL.chr[li][2]))
            return(0);
                              /* compute leaf location in view */
      VCOPY(wp, qtL.wp[li]);
      viewloc(ip, &odev.v, wp);
      if (ip[2] <= 0. || ip[0] < 0. || ip[0] >= 1.
                  || ip[1] < 0. || ip[1] >= 1.)
            goto dropit;                  /* behind or outside view */
#ifdef DEBUG
      if (odev.v.type == VT_PAR | odev.v.vfore > FTINY)
            error(INTERNAL, "bad view assumption in putleaf");
#endif
      for (q = 0; q < 3; q++)
            vd[q] = (wp[q] - odev.v.vp[q])/ip[2];
      d2 = fdir2diff(qtL.wd[li], vd);
#ifdef MAXDIFF2
      if (d2 > MAXDIFF2)
            goto dropit;                  /* leaf dir. too far off */
#endif
      x = ip[0] * odev.hres;
      y = ip[1] * odev.vres;
      z = ip[2];
                              /* find the place for it */
      for ( ; ; ) {
            q = 0;                        /* which quadrant? */
            mx = (x0 + x1) >> 1;
            my = (y0 + y1) >> 1;
            if (x < mx) x1 = mx;
            else {x0 = mx; q |= 01;}
            if (y < my) y1 = my;
            else {y0 = my; q |= 02;}
            if (tp->flgs & BRF(q)) {      /* move to next branch */
                  tp->flgs |= CHF(q);           /* not sure; guess */
                  tp = tp->k[q].b;
                  continue;
            }
            if (!(tp->flgs & LFF(q))) {   /* found stem for leaf */
                  tp->k[q].li = li;
                  tp->flgs |= CHLFF(q);
                  return(1);
            }     
            if (lo != tp->k[q].li) {      /* check old leaf */
                  lo = tp->k[q].li;
                  VCOPY(wp, qtL.wp[lo]);
                  viewloc(ip, &odev.v, wp);
            }
                                    /* is node minimum size? */
            if (y1-y0 <= qtMinNodesiz || x1-x0 <= qtMinNodesiz) {
                  if (z > (1.+qtDepthEps)*ip[2])
                        break;                  /* old one closer */
                  if (z >= (1.-qtDepthEps)*ip[2] &&
                              fdir2diff(qtL.wd[lo], vd) < d2)
                        break;                  /* old one better */
                  tp->k[q].li = li;       /* attach new */
                  tp->flgs |= CHF(q);
                  li = lo;                /* drop old... */
                  break;
            }
            tp->flgs &= ~LFF(q);          /* else grow tree */
            tp->flgs |= CHBRF(q);
            tp = tp->k[q].b = newtwig();
            q = 0;                        /* old leaf -> new branch */
            mx = ip[0] * odev.hres;
            my = ip[1] * odev.vres;
            if (mx >= (x0 + x1) >> 1) q |= 01;
            if (my >= (y0 + y1) >> 1) q |= 02;
            tp->flgs = CH_ANY|LFF(q);     /* all new */
            tp->k[q].li = lo;
      }
dropit:
      if (drop) {
            if (li+1 == (qtL.tl ? qtL.tl : qtL.nl))
                  qtL.tl = li;            /* special case */
            else {
                  qtL.chr[li][0] = qtL.chr[li][1] = qtL.chr[li][2] = 0;
                  qtL.wd[li] = falleaves;
                  falleaves = li;
            }
      }
      return(li == lo);
}


extern void
dev_value(        /* add a pixel value to our quadtree */
      COLR  c,
      FVECT d,
      FVECT p
)
{
      register int      li;
      int   mapit;
                        /* grab a leaf */
      if (!imm_mode && falleaves >= 0) {  /* check for fallen leaves */
            li = falleaves;
            falleaves = qtL.wd[li];
            mapit = qtL.tml <= qtL.tl ?
                        (li < qtL.tml || li >= qtL.tl) :
                        (li < qtL.tml && li >= qtL.tl) ;
      } else {                      /* else allocate new one */
            li = qtL.tl++;
            if (qtL.tl >= qtL.nl)         /* next leaf in ring */
                  qtL.tl = 0;
            if (qtL.tl == qtL.bl)         /* need to shake some free */
                  qtCompost(LFREEPCT);
            mapit = 0;              /* we'll map it later */
      }
      if (p == NULL)
            VSUM(qtL.wp[li], odev.v.vp, d, FHUGE);
      else
            VCOPY(qtL.wp[li], p);
      qtL.wd[li] = encodedir(d);
      tmCvColrs(tmGlobal, &qtL.brt[li], qtL.chr[li], (COLR *)c, 1);
      if (putleaf(li, 1)) {
            if (mapit)
                  tmMapPixels(tmGlobal, (BYTE *)(qtL.rgb+li), qtL.brt+li,
                              (BYTE *)(qtL.chr+li), 1);
            if (--rayqleft == 0)
                  dev_flush();            /* flush output */
      }
}


extern void
qtReplant(void)               /* replant our tree using new view */
{
      register int      i;
                              /* anything to replant? */
      if (qtL.bl == qtL.tl)
            return;
      qtFreeTree(0);                /* blow the old tree away */
                              /* regrow it in new place */
      for (i = qtL.bl; i != qtL.tl; ) {
            putleaf(i, 0);
            if (++i >= qtL.nl) i = 0;
      }
}


extern int
qtMapLeaves(            /* map our leaves to RGB */
      int   redo
)
{
      int   aorg, alen, borg, blen;
                              /* recompute mapping? */
      if (redo)
            qtL.tml = qtL.bl;
                              /* already done? */
      if (qtL.tml == qtL.tl)
            return(1);
                              /* compute segments */
      aorg = qtL.tml;
      if (qtL.tl >= aorg) {
            alen = qtL.tl - aorg;
            blen = 0;
      } else {
            alen = qtL.nl - aorg;
            borg = 0;
            blen = qtL.tl;
      }
                              /* (re)compute tone mapping? */
      if (qtL.tml == qtL.bl) {
            tmClearHisto(tmGlobal);
            tmAddHisto(tmGlobal, qtL.brt+aorg, alen, 1);
            if (blen > 0)
                  tmAddHisto(tmGlobal, qtL.brt+borg, blen, 1);
            if (tmComputeMapping(tmGlobal, 0., 0., 0.) != TM_E_OK)
                  return(0);
      }
      if (tmMapPixels(tmGlobal, (BYTE *)(qtL.rgb+aorg), qtL.brt+aorg,
                  (BYTE *)(qtL.chr+aorg), alen) != TM_E_OK)
            return(0);
      if (blen > 0)
            tmMapPixels(tmGlobal, (BYTE *)(qtL.rgb+borg), qtL.brt+borg,
                        (BYTE *)(qtL.chr+borg), blen);
      qtL.tml = qtL.tl;
      return(1);
}

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