--- ray/src/common/bsdf_t.c 2011/02/18 00:41:44 3.2 +++ ray/src/common/bsdf_t.c 2011/08/22 05:48:39 3.21 @@ -1,5 +1,5 @@ #ifndef lint -static const char RCSid[] = "$Id: bsdf_t.c,v 3.2 2011/02/18 00:41:44 greg Exp $"; +static const char RCSid[] = "$Id: bsdf_t.c,v 3.21 2011/08/22 05:48:39 greg Exp $"; #endif /* * bsdf_t.c @@ -10,12 +10,42 @@ static const char RCSid[] = "$Id: bsdf_t.c,v 3.2 2011/ * */ -#include +#define _USE_MATH_DEFINES +#include "rtio.h" #include +#include +#include #include "ezxml.h" #include "bsdf.h" #include "bsdf_t.h" +#include "hilbert.h" +/* Callback function type for SDtraverseTre() */ +typedef int SDtreCallback(float val, const double *cmin, + double csiz, void *cptr); + + /* reference width maximum (1.0) */ +static const unsigned iwbits = sizeof(unsigned)*4; +static const unsigned iwmax = (1<<(sizeof(unsigned)*4))-1; + /* maximum cumulative value */ +static const unsigned cumlmax = ~0; + /* constant z-vector */ +static const FVECT zvec = {.0, .0, 1.}; + +/* Struct used for our distribution-building callback */ +typedef struct { + int nic; /* number of input coordinates */ + unsigned alen; /* current array length */ + unsigned nall; /* number of allocated entries */ + unsigned wmin; /* minimum square size so far */ + unsigned wmax; /* maximum square size */ + struct outdir_s { + unsigned hent; /* entering Hilbert index */ + int wid; /* this square size */ + float bsdf; /* BSDF for this square */ + } *darr; /* output direction array */ +} SDdistScaffold; + /* Allocate a new scattering distribution node */ static SDNode * SDnewNode(int nd, int lg) @@ -33,21 +63,21 @@ SDnewNode(int nd, int lg) } if (lg < 0) { st = (SDNode *)malloc(sizeof(SDNode) + - ((1<u.t[0])); - if (st != NULL) - memset(st->u.t, 0, (1<u.t[0])); - } else + sizeof(st->u.t[0])*((1<u.t, 0, sizeof(st->u.t[0])<u.v[0])); - - if (st == NULL) { - if (lg < 0) + sizeof(st->u.v[0])*((1 << nd*lg) - 1)); + if (st == NULL) { sprintf(SDerrorDetail, - "Cannot allocate %d branch BSDF tree", nd); - else - sprintf(SDerrorDetail, "Cannot allocate %d BSDF leaves", 1 << nd*lg); - return NULL; + return NULL; + } } st->ndim = nd; st->log2GR = lg; @@ -56,43 +86,129 @@ SDnewNode(int nd, int lg) /* Free an SD tree */ static void -SDfreeTree(void *p) +SDfreeTre(SDNode *st) { - SDNode *st = (SDNode *)p; - int i; + int n; if (st == NULL) return; - for (i = (st->log2GR < 0) << st->ndim; i--; ) - SDfreeTree(st->u.t[i]); - free((void *)st); + for (n = (st->log2GR < 0) << st->ndim; n--; ) + SDfreeTre(st->u.t[n]); + free(st); } +/* Free a variable-resolution BSDF */ +static void +SDFreeBTre(void *p) +{ + SDTre *sdt = (SDTre *)p; + + if (sdt == NULL) + return; + SDfreeTre(sdt->st); + free(sdt); +} + +/* Fill branch's worth of grid values from subtree */ +static void +fill_grid_branch(float *dptr, const float *sptr, int nd, int shft) +{ + unsigned n = 1 << (shft-1); + + if (!--nd) { /* end on the line */ + memcpy(dptr, sptr, sizeof(*dptr)*n); + return; + } + while (n--) /* recurse on each slice */ + fill_grid_branch(dptr + (n << shft*nd), + sptr + (n << (shft-1)*nd), nd, shft); +} + +/* Get pointer at appropriate offset for the given branch */ +static float * +grid_branch_start(SDNode *st, int n) +{ + unsigned skipsiz = 1 << (st->log2GR - 1); + float *vptr = st->u.v; + int i; + + for (i = st->ndim; i--; skipsiz <<= st->log2GR) + if (1<log2GR >= 0) /* grid just returns unaltered */ + return st; + match = 1; /* check if grids below match */ + for (n = 0; n < 1<ndim; n++) { + if ((st->u.t[n] = SDsimplifyTre(st->u.t[n])) == NULL) + return NULL; /* propogate error up call stack */ + match &= (st->u.t[n]->log2GR == st->u.t[0]->log2GR); + } + if (match && (match = st->u.t[0]->log2GR) >= 0) { + SDNode *stn = SDnewNode(st->ndim, match + 1); + if (stn == NULL) /* out of memory? */ + return st; + /* transfer values to new grid */ + for (n = 1 << st->ndim; n--; ) + fill_grid_branch(grid_branch_start(stn, n), + st->u.t[n]->u.v, stn->ndim, stn->log2GR); + SDfreeTre(st); /* free old tree */ + st = stn; /* return new one */ + } + return st; +} + +/* Find smallest leaf in tree */ +static double +SDsmallestLeaf(const SDNode *st) +{ + if (st->log2GR < 0) { /* tree branches */ + double lmin = 1.; + int n; + for (n = 1<ndim; n--; ) { + double lsiz = SDsmallestLeaf(st->u.t[n]); + if (lsiz < lmin) + lmin = lsiz; + } + return .5*lmin; + } + /* leaf grid width */ + return 1. / (double)(1 << st->log2GR); +} + /* Add up N-dimensional hypercube array values over the given box */ static double -SDiterSum(const float *va, int nd, int siz, const int *imin, const int *imax) +SDiterSum(const float *va, int nd, int shft, const int *imin, const int *imax) { + const unsigned skipsiz = 1 << --nd*shft; double sum = .0; - unsigned skipsiz = 1; int i; - - for (i = nd; --i > 0; ) - skipsiz *= siz; + + va += *imin * skipsiz; + if (skipsiz == 1) for (i = *imin; i < *imax; i++) - sum += va[i]; + sum += *va++; else - for (i = *imin; i < *imax; i++) - sum += SDiterSum(va + i*skipsiz, - nd-1, siz, imin+1, imax+1); + for (i = *imin; i < *imax; i++, va += skipsiz) + sum += SDiterSum(va, nd, shft, imin+1, imax+1); return sum; } /* Average BSDF leaves over an orthotope defined by the unit hypercube */ static double -SDavgBox(const SDNode *st, const double *bmin, const double *bmax) +SDavgTreBox(const SDNode *st, const double *bmin, const double *bmax) { - int imin[SD_MAXDIM], imax[SD_MAXDIM]; unsigned n; int i; @@ -102,7 +218,7 @@ SDavgBox(const SDNode *st, const double *bmin, const d for (i = st->ndim; i--; ) { if (bmin[i] >= 1.) return .0; - if (bmax[i] <= .0) + if (bmax[i] <= 0) return .0; if (bmin[i] >= bmax[i]) return .0; @@ -110,7 +226,6 @@ SDavgBox(const SDNode *st, const double *bmin, const d if (st->log2GR < 0) { /* iterate on subtree */ double sum = .0, wsum = 1e-20; double sbmin[SD_MAXDIM], sbmax[SD_MAXDIM], w; - for (n = 1 << st->ndim; n--; ) { w = 1.; for (i = st->ndim; i--; ) { @@ -122,42 +237,869 @@ SDavgBox(const SDNode *st, const double *bmin, const d } if (sbmin[i] < .0) sbmin[i] = .0; if (sbmax[i] > 1.) sbmax[i] = 1.; + if (sbmin[i] >= sbmax[i]) { + w = .0; + break; + } w *= sbmax[i] - sbmin[i]; } if (w > 1e-10) { - sum += w * SDavgBox(st->u.t[n], sbmin, sbmax); + sum += w * SDavgTreBox(st->u.t[n], sbmin, sbmax); wsum += w; } } return sum / wsum; + } else { /* iterate over leaves */ + int imin[SD_MAXDIM], imax[SD_MAXDIM]; + + n = 1; + for (i = st->ndim; i--; ) { + imin[i] = (bmin[i] <= 0) ? 0 : + (int)((1 << st->log2GR)*bmin[i]); + imax[i] = (bmax[i] >= 1.) ? (1 << st->log2GR) : + (int)((1 << st->log2GR)*bmax[i] + .999999); + n *= imax[i] - imin[i]; + } + if (n) + return SDiterSum(st->u.v, st->ndim, + st->log2GR, imin, imax) / (double)n; } - n = 1; /* iterate over leaves */ + return .0; +} + +/* Recursive call for SDtraverseTre() */ +static int +SDdotravTre(const SDNode *st, const double *pos, int cmask, + SDtreCallback *cf, void *cptr, + const double *cmin, double csiz) +{ + int rv, rval = 0; + double bmin[SD_MAXDIM]; + int i, n; + /* in branches? */ + if (st->log2GR < 0) { + unsigned skipmask = 0; + csiz *= .5; + for (i = st->ndim; i--; ) + if (1<ndim; n--; ) { + if (n & 1<ndim; n--; ) { + if (!(n & 1<ndim; n--; ) { + if (1<ndim; i--; ) + if (1<u.t[n], pos, cmask, + cf, cptr, bmin, csiz); + if (rv < 0) + return rv; + } + } else { /* else traverse leaves */ + int clim[SD_MAXDIM][2]; + int cpos[SD_MAXDIM]; + + if (st->log2GR == 0) /* short cut */ + return (*cf)(st->u.v[0], cmin, csiz, cptr); + + csiz /= (double)(1 << st->log2GR); + /* assign coord. ranges */ + for (i = st->ndim; i--; ) + if (1<> st->log2GR; + clim[i][1] = clim[i][0] + 1; + } else { + clim[i][0] = 0; + clim[i][1] = 1 << st->log2GR; + } +#if (SD_MAXDIM == 4) + bmin[0] = cmin[0] + csiz*clim[0][0]; + for (cpos[0] = clim[0][0]; cpos[0] < clim[0][1]; cpos[0]++) { + bmin[1] = cmin[1] + csiz*clim[1][0]; + for (cpos[1] = clim[1][0]; cpos[1] < clim[1][1]; cpos[1]++) { + bmin[2] = cmin[2] + csiz*clim[2][0]; + if (st->ndim == 3) { + cpos[2] = clim[2][0]; + n = cpos[0]; + for (i = 1; i < 3; i++) + n = (n << st->log2GR) + cpos[i]; + for ( ; cpos[2] < clim[2][1]; cpos[2]++) { + rval += rv = (*cf)(st->u.v[n++], bmin, csiz, cptr); + if (rv < 0) + return rv; + bmin[2] += csiz; + } + } else { + for (cpos[2] = clim[2][0]; cpos[2] < clim[2][1]; cpos[2]++) { + bmin[3] = cmin[3] + csiz*(cpos[3] = clim[3][0]); + n = cpos[0]; + for (i = 1; i < 4; i++) + n = (n << st->log2GR) + cpos[i]; + for ( ; cpos[3] < clim[3][1]; cpos[3]++) { + rval += rv = (*cf)(st->u.v[n++], bmin, csiz, cptr); + if (rv < 0) + return rv; + bmin[3] += csiz; + } + bmin[2] += csiz; + } + } + bmin[1] += csiz; + } + bmin[0] += csiz; + } +#else + _!_ "broken code segment!" +#endif + } + return rval; +} + +/* Traverse a tree, visiting nodes in a slice that fits partial position */ +static int +SDtraverseTre(const SDNode *st, const double *pos, int cmask, + SDtreCallback *cf, void *cptr) +{ + static double czero[SD_MAXDIM]; + int i; + /* check arguments */ + if ((st == NULL) | (cf == NULL)) + return -1; + for (i = st->ndim; i--; ) + if (1<= 1.)) + return -1; + + return SDdotravTre(st, pos, cmask, cf, cptr, czero, 1.); +} + +/* Look up tree value at the given grid position */ +static float +SDlookupTre(const SDNode *st, const double *pos, double *hcube) +{ + double spos[SD_MAXDIM]; + int i, n, t; + /* initialize voxel return */ + if (hcube) { + hcube[i = st->ndim] = 1.; + while (i--) + hcube[i] = .0; + } + /* climb the tree */ + while (st->log2GR < 0) { + n = 0; /* move to appropriate branch */ + if (hcube) hcube[st->ndim] *= .5; + for (i = st->ndim; i--; ) { + spos[i] = 2.*pos[i]; + t = (spos[i] >= 1.); + n |= t<ndim]; + } + st = st->u.t[n]; /* avoids tail recursion */ + pos = spos; + } + if (st->log2GR == 0) /* short cut */ + return st->u.v[0]; + n = t = 0; /* find grid array index */ for (i = st->ndim; i--; ) { - imin[i] = (bmin[i] <= .0) ? 0 - : (int)((1 << st->log2GR)*bmin[i]); - imax[i] = (bmax[i] >= 1.) ? (1 << st->log2GR) - : (int)((1 << st->log2GR)*bmax[i] + .999999); - n *= imax[i] - imin[i]; + n += (int)((1<log2GR)*pos[i]) << t; + t += st->log2GR; } - if (!n) + if (hcube) { /* compute final hypercube */ + hcube[st->ndim] /= (double)(1<log2GR); + for (i = st->ndim; i--; ) + hcube[i] += floor((1<log2GR)*pos[i])*hcube[st->ndim]; + } + return st->u.v[n]; /* no interpolation */ +} + +/* Query BSDF value and sample hypercube for the given vectors */ +static float +SDqueryTre(const SDTre *sdt, const FVECT outVec, const FVECT inVec, double *hc) +{ + FVECT rOutVec; + double gridPos[4]; + + switch (sdt->sidef) { /* whose side are you on? */ + case SD_UFRONT: + if ((outVec[2] < 0) | (inVec[2] < 0)) + return -1.; + break; + case SD_UBACK: + if ((outVec[2] > 0) | (inVec[2] > 0)) + return -1.; + break; + case SD_XMIT: + if ((outVec[2] > 0) == (inVec[2] > 0)) + return -1.; + break; + default: + return -1.; + } + /* convert vector coordinates */ + if (sdt->st->ndim == 3) { + spinvector(rOutVec, outVec, zvec, -atan2(-inVec[1],-inVec[0])); + gridPos[0] = .5 - .5*sqrt(inVec[0]*inVec[0] + inVec[1]*inVec[1]); + SDdisk2square(gridPos+1, rOutVec[0], rOutVec[1]); + } else if (sdt->st->ndim == 4) { + SDdisk2square(gridPos, -inVec[0], -inVec[1]); + SDdisk2square(gridPos+2, outVec[0], outVec[1]); + } else + return -1.; /* should be internal error */ + + return SDlookupTre(sdt->st, gridPos, hc); +} + +/* Compute non-diffuse component for variable-resolution BSDF */ +static int +SDgetTreBSDF(float coef[SDmaxCh], const FVECT outVec, + const FVECT inVec, SDComponent *sdc) +{ + /* check arguments */ + if ((coef == NULL) | (outVec == NULL) | (inVec == NULL) | (sdc == NULL) + || sdc->dist == NULL) + return 0; + /* get nearest BSDF value */ + coef[0] = SDqueryTre((SDTre *)sdc->dist, outVec, inVec, NULL); + return (coef[0] >= 0); /* monochromatic for now */ +} + +/* Callback to build cumulative distribution using SDtraverseTre() */ +static int +build_scaffold(float val, const double *cmin, double csiz, void *cptr) +{ + SDdistScaffold *sp = (SDdistScaffold *)cptr; + int wid = csiz*(double)iwmax + .5; + bitmask_t bmin[2], bmax[2]; + + cmin += sp->nic; /* skip to output coords */ + if (wid < sp->wmin) /* new minimum width? */ + sp->wmin = wid; + if (wid > sp->wmax) /* new maximum? */ + sp->wmax = wid; + if (sp->alen >= sp->nall) { /* need more space? */ + struct outdir_s *ndarr; + sp->nall += 1024; + ndarr = (struct outdir_s *)realloc(sp->darr, + sizeof(struct outdir_s)*sp->nall); + if (ndarr == NULL) { + sprintf(SDerrorDetail, + "Cannot grow scaffold to %u entries", sp->nall); + return -1; /* abort build */ + } + sp->darr = ndarr; + } + /* find Hilbert entry index */ + bmin[0] = cmin[0]*(double)iwmax + .5; + bmin[1] = cmin[1]*(double)iwmax + .5; + bmax[0] = bmin[0] + wid-1; + bmax[1] = bmin[1] + wid-1; + hilbert_box_vtx(2, sizeof(bitmask_t), iwbits, 1, bmin, bmax); + sp->darr[sp->alen].hent = hilbert_c2i(2, iwbits, bmin); + sp->darr[sp->alen].wid = wid; + sp->darr[sp->alen].bsdf = val; + sp->alen++; /* on to the next entry */ + return 0; +} + +/* Scaffold comparison function for qsort -- ascending Hilbert index */ +static int +sscmp(const void *p1, const void *p2) +{ + unsigned h1 = (*(const struct outdir_s *)p1).hent; + unsigned h2 = (*(const struct outdir_s *)p2).hent; + + if (h1 > h2) + return 1; + if (h1 < h2) + return -1; + return 0; +} + +/* Create a new cumulative distribution for the given input direction */ +static SDTreCDst * +make_cdist(const SDTre *sdt, const double *pos) +{ + SDdistScaffold myScaffold; + SDTreCDst *cd; + struct outdir_s *sp; + double scale, cursum; + int i; + /* initialize scaffold */ + myScaffold.wmin = iwmax; + myScaffold.wmax = 0; + myScaffold.nic = sdt->st->ndim - 2; + myScaffold.alen = 0; + myScaffold.nall = 512; + myScaffold.darr = (struct outdir_s *)malloc(sizeof(struct outdir_s) * + myScaffold.nall); + if (myScaffold.darr == NULL) + return NULL; + /* grow the distribution */ + if (SDtraverseTre(sdt->st, pos, (1<carr[0])*myScaffold.alen); + if (cd == NULL) { + sprintf(SDerrorDetail, + "Cannot allocate %u entry cumulative distribution", + myScaffold.alen); + free(myScaffold.darr); + return NULL; + } + cd->isodist = (myScaffold.nic == 1); + /* sort the distribution */ + qsort(myScaffold.darr, cd->calen = myScaffold.alen, + sizeof(struct outdir_s), &sscmp); + + /* record input range */ + scale = myScaffold.wmin / (double)iwmax; + for (i = myScaffold.nic; i--; ) { + cd->clim[i][0] = floor(pos[i]/scale) * scale; + cd->clim[i][1] = cd->clim[i][0] + scale; + } + if (cd->isodist) { /* avoid issue in SDqueryTreProjSA() */ + cd->clim[1][0] = cd->clim[0][0]; + cd->clim[1][1] = cd->clim[0][1]; + } + cd->max_psa = myScaffold.wmax / (double)iwmax; + cd->max_psa *= cd->max_psa * M_PI; + cd->sidef = sdt->sidef; + cd->cTotal = 1e-20; /* compute directional total */ + sp = myScaffold.darr; + for (i = myScaffold.alen; i--; sp++) + cd->cTotal += sp->bsdf * (double)sp->wid * sp->wid; + cursum = .0; /* go back and get cumulative values */ + scale = (double)cumlmax / cd->cTotal; + sp = myScaffold.darr; + for (i = 0; i < cd->calen; i++, sp++) { + cd->carr[i].hndx = sp->hent; + cd->carr[i].cuml = scale*cursum + .5; + cursum += sp->bsdf * (double)sp->wid * sp->wid; + } + cd->carr[i].hndx = ~0; /* make final entry */ + cd->carr[i].cuml = cumlmax; + cd->cTotal *= M_PI/(double)iwmax/iwmax; + /* all done, clean up and return */ + free(myScaffold.darr); + return cd; +} + +/* Find or allocate a cumulative distribution for the given incoming vector */ +const SDCDst * +SDgetTreCDist(const FVECT inVec, SDComponent *sdc) +{ + const SDTre *sdt; + double inCoord[2], quantum; + int i; + SDTreCDst *cd, *cdlast; + /* check arguments */ + if ((inVec == NULL) | (sdc == NULL) || + (sdt = (SDTre *)sdc->dist) == NULL) + return NULL; + if (sdt->st->ndim == 3) { /* isotropic BSDF? */ + inCoord[0] = .5 - .5*sqrt(inVec[0]*inVec[0] + inVec[1]*inVec[1]); + } else if (sdt->st->ndim == 4) { + SDdisk2square(inCoord, -inVec[0], -inVec[1]); + } else + return NULL; /* should be internal error */ + /* quantize to avoid f.p. errors */ + quantum = SDsmallestLeaf(sdt->st); + for (i = sdt->st->ndim - 2; i--; ) + inCoord[i] = floor(inCoord[i]/quantum)*quantum + .5*quantum; + cdlast = NULL; /* check for direction in cache list */ + for (cd = (SDTreCDst *)sdc->cdList; cd != NULL; + cdlast = cd, cd = cd->next) { + for (i = sdt->st->ndim - 2; i--; ) + if ((cd->clim[i][0] > inCoord[i]) | + (inCoord[i] >= cd->clim[i][1])) + break; + if (i < 0) + break; /* means we have a match */ + } + if (cd == NULL) /* need to create new entry? */ + cdlast = cd = make_cdist(sdt, inCoord); + if (cdlast != NULL) { /* move entry to head of cache list */ + cdlast->next = cd->next; + cd->next = (SDTreCDst *)sdc->cdList; + sdc->cdList = (SDCDst *)cd; + } + return (SDCDst *)cd; /* ready to go */ +} + +/* Query solid angle for vector(s) */ +static SDError +SDqueryTreProjSA(double *psa, const FVECT v1, const RREAL *v2, + int qflags, SDComponent *sdc) +{ + double myPSA[2]; + /* check arguments */ + if ((psa == NULL) | (v1 == NULL) | (sdc == NULL) || + sdc->dist == NULL) + return SDEargument; + /* get projected solid angle(s) */ + if (v2 != NULL) { + const SDTre *sdt = (SDTre *)sdc->dist; + double hcube[SD_MAXDIM]; + if (SDqueryTre(sdt, v1, v2, hcube) < 0) { + strcpy(SDerrorDetail, "Bad call to SDqueryTreProjSA"); + return SDEinternal; + } + myPSA[0] = hcube[sdt->st->ndim]; + myPSA[1] = myPSA[0] *= myPSA[0] * M_PI; + } else { + const SDTreCDst *cd = (const SDTreCDst *)SDgetTreCDist(v1, sdc); + if (cd == NULL) + return SDEmemory; + myPSA[0] = M_PI * (cd->clim[0][1] - cd->clim[0][0]) * + (cd->clim[1][1] - cd->clim[1][0]); + myPSA[1] = cd->max_psa; + } + switch (qflags) { /* record based on flag settings */ + case SDqueryVal: + *psa = myPSA[0]; + break; + case SDqueryMax: + if (myPSA[1] > *psa) + *psa = myPSA[1]; + break; + case SDqueryMin+SDqueryMax: + if (myPSA[1] > psa[1]) + psa[1] = myPSA[1]; + /* fall through */ + case SDqueryMin: + if (myPSA[0] < psa[0]) + psa[0] = myPSA[0]; + break; + } + return SDEnone; +} + +/* Sample cumulative distribution */ +static SDError +SDsampTreCDist(FVECT ioVec, double randX, const SDCDst *cdp) +{ + const unsigned nBitsC = 4*sizeof(bitmask_t); + const unsigned nExtraBits = 8*(sizeof(bitmask_t)-sizeof(unsigned)); + const SDTreCDst *cd = (const SDTreCDst *)cdp; + const unsigned target = randX*cumlmax; + bitmask_t hndx, hcoord[2]; + double gpos[3], rotangle; + int i, iupper, ilower; + /* check arguments */ + if ((ioVec == NULL) | (cd == NULL)) + return SDEargument; + if (ioVec[2] > 0) { + if (!(cd->sidef & SD_UFRONT)) + return SDEargument; + } else if (!(cd->sidef & SD_UBACK)) + return SDEargument; + /* binary search to find position */ + ilower = 0; iupper = cd->calen; + while ((i = (iupper + ilower) >> 1) != ilower) + if (target >= cd->carr[i].cuml) + ilower = i; + else + iupper = i; + /* localize random position */ + randX = (randX*cumlmax - cd->carr[ilower].cuml) / + (double)(cd->carr[iupper].cuml - cd->carr[ilower].cuml); + /* index in longer Hilbert curve */ + hndx = (randX*cd->carr[iupper].hndx + (1.-randX)*cd->carr[ilower].hndx) + * (double)((bitmask_t)1 << nExtraBits); + /* convert Hilbert index to vector */ + hilbert_i2c(2, nBitsC, hndx, hcoord); + for (i = 2; i--; ) + gpos[i] = ((double)hcoord[i] + rand()*(1./(RAND_MAX+.5))) / + (double)((bitmask_t)1 << nBitsC); + SDsquare2disk(gpos, gpos[0], gpos[1]); + /* compute Z-coordinate */ + gpos[2] = 1. - gpos[0]*gpos[0] - gpos[1]*gpos[1]; + if (gpos[2] > 0) /* paranoia, I hope */ + gpos[2] = sqrt(gpos[2]); + /* emit from back? */ + if (ioVec[2] > 0 ^ cd->sidef != SD_XMIT) + gpos[2] = -gpos[2]; + if (cd->isodist) { /* rotate isotropic result */ + rotangle = atan2(-ioVec[1],-ioVec[0]); + VCOPY(ioVec, gpos); + spinvector(ioVec, ioVec, zvec, rotangle); + } else + VCOPY(ioVec, gpos); + return SDEnone; +} + +/* Advance pointer to the next non-white character in the string (or nul) */ +static int +next_token(char **spp) +{ + while (isspace(**spp)) + ++*spp; + return **spp; +} + +/* Advance pointer past matching token (or any token if c==0) */ +#define eat_token(spp,c) (next_token(spp)==(c) ^ !(c) ? *(*(spp))++ : 0) + +/* Count words from this point in string to '}' */ +static int +count_values(char *cp) +{ + int n = 0; + + while (next_token(&cp) != '}' && *cp) { + while (!isspace(*cp) & (*cp != ',') & (*cp != '}')) + if (!*++cp) + break; + ++n; + eat_token(&cp, ','); + } + return n; +} + +/* Load an array of real numbers, returning total */ +static int +load_values(char **spp, float *va, int n) +{ + float *v = va; + char *svnext; + + while (n-- > 0 && (svnext = fskip(*spp)) != NULL) { + *v++ = atof(*spp); + *spp = svnext; + eat_token(spp, ','); + } + return v - va; +} + +/* Load BSDF tree data */ +static SDNode * +load_tree_data(char **spp, int nd) +{ + SDNode *st; + int n; + + if (!eat_token(spp, '{')) { + strcpy(SDerrorDetail, "Missing '{' in tensor tree"); + return NULL; + } + if (next_token(spp) == '{') { /* tree branches */ + st = SDnewNode(nd, -1); + if (st == NULL) + return NULL; + for (n = 0; n < 1<u.t[n] = load_tree_data(spp, nd)) == NULL) { + SDfreeTre(st); + return NULL; + } + } else { /* else load value grid */ + int bsiz; + n = count_values(*spp); /* see how big the grid is */ + for (bsiz = 0; bsiz < 8*sizeof(size_t); bsiz += nd) + if (1<= 8*sizeof(size_t)) { + strcpy(SDerrorDetail, "Illegal value count in tensor tree"); + return NULL; + } + st = SDnewNode(nd, bsiz/nd); + if (st == NULL) + return NULL; + if (load_values(spp, st->u.v, n) != n) { + strcpy(SDerrorDetail, "Real format error in tensor tree"); + SDfreeTre(st); + return NULL; + } + } + if (!eat_token(spp, '}')) { + strcpy(SDerrorDetail, "Missing '}' in tensor tree"); + SDfreeTre(st); + return NULL; + } + eat_token(spp, ','); + return st; +} + +/* Compute min. proj. solid angle and max. direct hemispherical scattering */ +static SDError +get_extrema(SDSpectralDF *df) +{ + SDNode *st = (*(SDTre *)df->comp[0].dist).st; + double stepWidth, dhemi, bmin[4], bmax[4]; + + stepWidth = SDsmallestLeaf(st); + df->minProjSA = M_PI*stepWidth*stepWidth; + if (stepWidth < .03125) + stepWidth = .03125; /* 1/32 resolution good enough */ + df->maxHemi = .0; + if (st->ndim == 3) { /* isotropic BSDF */ + bmin[1] = bmin[2] = .0; + bmax[1] = bmax[2] = 1.; + for (bmin[0] = .0; bmin[0] < .5-FTINY; bmin[0] += stepWidth) { + bmax[0] = bmin[0] + stepWidth; + dhemi = SDavgTreBox(st, bmin, bmax); + if (dhemi > df->maxHemi) + df->maxHemi = dhemi; + } + } else if (st->ndim == 4) { /* anisotropic BSDF */ + bmin[2] = bmin[3] = .0; + bmax[2] = bmax[3] = 1.; + for (bmin[0] = .0; bmin[0] < 1.-FTINY; bmin[0] += stepWidth) { + bmax[0] = bmin[0] + stepWidth; + for (bmin[1] = .0; bmin[1] < 1.-FTINY; bmin[1] += stepWidth) { + bmax[1] = bmin[1] + stepWidth; + dhemi = SDavgTreBox(st, bmin, bmax); + if (dhemi > df->maxHemi) + df->maxHemi = dhemi; + } + } + } else + return SDEinternal; + /* correct hemispherical value */ + df->maxHemi *= M_PI; + return SDEnone; +} + +/* Load BSDF distribution for this wavelength */ +static SDError +load_bsdf_data(SDData *sd, ezxml_t wdb, int ndim) +{ + SDSpectralDF *df; + SDTre *sdt; + char *sdata; + /* allocate BSDF component */ + sdata = ezxml_txt(ezxml_child(wdb, "WavelengthDataDirection")); + if (!sdata) + return SDEnone; + /* + * Remember that front and back are reversed from WINDOW 6 orientations + */ + if (!strcasecmp(sdata, "Transmission")) { + if (sd->tf != NULL) + SDfreeSpectralDF(sd->tf); + if ((sd->tf = SDnewSpectralDF(1)) == NULL) + return SDEmemory; + df = sd->tf; + } else if (!strcasecmp(sdata, "Reflection Front")) { + if (sd->rb != NULL) /* note back-front reversal */ + SDfreeSpectralDF(sd->rb); + if ((sd->rb = SDnewSpectralDF(1)) == NULL) + return SDEmemory; + df = sd->rb; + } else if (!strcasecmp(sdata, "Reflection Back")) { + if (sd->rf != NULL) /* note front-back reversal */ + SDfreeSpectralDF(sd->rf); + if ((sd->rf = SDnewSpectralDF(1)) == NULL) + return SDEmemory; + df = sd->rf; + } else + return SDEnone; + /* XXX should also check "ScatteringDataType" for consistency? */ + /* get angle bases */ + sdata = ezxml_txt(ezxml_child(wdb,"AngleBasis")); + if (!sdata || strcasecmp(sdata, "LBNL/Shirley-Chiu")) { + sprintf(SDerrorDetail, "%s angle basis for BSDF '%s'", + !sdata ? "Missing" : "Unsupported", sd->name); + return !sdata ? SDEformat : SDEsupport; + } + /* allocate BSDF tree */ + sdt = (SDTre *)malloc(sizeof(SDTre)); + if (sdt == NULL) + return SDEmemory; + if (df == sd->rf) + sdt->sidef = SD_UFRONT; + else if (df == sd->rb) + sdt->sidef = SD_UBACK; + else + sdt->sidef = SD_XMIT; + sdt->st = NULL; + df->comp[0].cspec[0] = c_dfcolor; /* XXX monochrome for now */ + df->comp[0].dist = sdt; + df->comp[0].func = &SDhandleTre; + /* read BSDF data */ + sdata = ezxml_txt(ezxml_child(wdb, "ScatteringData")); + if (!sdata || !next_token(&sdata)) { + sprintf(SDerrorDetail, "Missing BSDF ScatteringData in '%s'", + sd->name); + return SDEformat; + } + sdt->st = load_tree_data(&sdata, ndim); + if (sdt->st == NULL) + return SDEformat; + if (next_token(&sdata)) { /* check for unconsumed characters */ + sprintf(SDerrorDetail, + "Extra characters at end of ScatteringData in '%s'", + sd->name); + return SDEformat; + } + /* flatten branches where possible */ + sdt->st = SDsimplifyTre(sdt->st); + if (sdt->st == NULL) + return SDEinternal; + return get_extrema(df); /* compute global quantities */ +} + +/* Find minimum value in tree */ +static float +SDgetTreMin(const SDNode *st) +{ + float vmin = FHUGE; + int n; + + if (st->log2GR < 0) { + for (n = 1<ndim; n--; ) { + float v = SDgetTreMin(st->u.t[n]); + if (v < vmin) + vmin = v; + } + } else { + for (n = 1<<(st->ndim*st->log2GR); n--; ) + if (st->u.v[n] < vmin) + vmin = st->u.v[n]; + } + return vmin; +} + +/* Subtract the given value from all tree nodes */ +static void +SDsubtractTreVal(SDNode *st, float val) +{ + int n; + + if (st->log2GR < 0) { + for (n = 1<ndim; n--; ) + SDsubtractTreVal(st->u.t[n], val); + } else { + for (n = 1<<(st->ndim*st->log2GR); n--; ) + if ((st->u.v[n] -= val) < 0) + st->u.v[n] = .0f; + } +} + +/* Subtract minimum value from BSDF */ +static double +subtract_min(SDNode *st) +{ + float vmin; + /* be sure to skip unused portion */ + if (st->ndim == 3) { + int n; + vmin = 1./M_PI; + if (st->log2GR < 0) { + for (n = 0; n < 8; n += 2) { + float v = SDgetTreMin(st->u.t[n]); + if (v < vmin) + vmin = v; + } + } else if (st->log2GR) { + for (n = 1 << (3*st->log2GR - 1); n--; ) + if (st->u.v[n] < vmin) + vmin = st->u.v[n]; + } else + vmin = st->u.v[0]; + } else /* anisotropic covers entire tree */ + vmin = SDgetTreMin(st); + + if (vmin <= FTINY) return .0; - - return SDiterSum(st->u.v, st->ndim, 1 << st->log2GR, imin, imax) / - (double)n; + + SDsubtractTreVal(st, vmin); + + return M_PI * vmin; /* return hemispherical value */ } +/* Extract and separate diffuse portion of BSDF */ +static void +extract_diffuse(SDValue *dv, SDSpectralDF *df) +{ + int n; + + if (df == NULL || df->ncomp <= 0) { + dv->spec = c_dfcolor; + dv->cieY = .0; + return; + } + dv->spec = df->comp[0].cspec[0]; + dv->cieY = subtract_min((*(SDTre *)df->comp[0].dist).st); + /* in case of multiple components */ + for (n = df->ncomp; --n; ) { + double ymin = subtract_min((*(SDTre *)df->comp[n].dist).st); + c_cmix(&dv->spec, dv->cieY, &dv->spec, ymin, &df->comp[n].cspec[0]); + dv->cieY += ymin; + } + df->maxHemi -= dv->cieY; /* adjust maximum hemispherical */ + /* make sure everything is set */ + c_ccvt(&dv->spec, C_CSXY+C_CSSPEC); +} + /* Load a variable-resolution BSDF tree from an open XML file */ SDError -SDloadTre(SDData *sd, ezxml_t fl) +SDloadTre(SDData *sd, ezxml_t wtl) { - return SDEsupport; + SDError ec; + ezxml_t wld, wdb; + int rank; + char *txt; + /* basic checks and tensor rank */ + txt = ezxml_txt(ezxml_child(ezxml_child(wtl, + "DataDefinition"), "IncidentDataStructure")); + if (txt == NULL || !*txt) { + sprintf(SDerrorDetail, + "BSDF \"%s\": missing IncidentDataStructure", + sd->name); + return SDEformat; + } + if (!strcasecmp(txt, "TensorTree3")) + rank = 3; + else if (!strcasecmp(txt, "TensorTree4")) + rank = 4; + else { + sprintf(SDerrorDetail, + "BSDF \"%s\": unsupported IncidentDataStructure", + sd->name); + return SDEsupport; + } + /* load BSDF components */ + for (wld = ezxml_child(wtl, "WavelengthData"); + wld != NULL; wld = wld->next) { + if (strcasecmp(ezxml_txt(ezxml_child(wld,"Wavelength")), + "Visible")) + continue; /* just visible for now */ + for (wdb = ezxml_child(wld, "WavelengthDataBlock"); + wdb != NULL; wdb = wdb->next) + if ((ec = load_bsdf_data(sd, wdb, rank)) != SDEnone) + return ec; + } + /* separate diffuse components */ + extract_diffuse(&sd->rLambFront, sd->rf); + extract_diffuse(&sd->rLambBack, sd->rb); + extract_diffuse(&sd->tLamb, sd->tf); + /* return success */ + return SDEnone; } /* Variable resolution BSDF methods */ -const SDFunc SDhandleTre = { - NULL, - NULL, - NULL, - NULL, - &SDfreeTree, +SDFunc SDhandleTre = { + &SDgetTreBSDF, + &SDqueryTreProjSA, + &SDgetTreCDist, + &SDsampTreCDist, + &SDFreeBTre, };