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greg |
2.1 |
#ifndef lint |
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static const char RCSid[] = "$Id: bsdf.c,v 2.1 2009/06/12 17:37:37 greg Exp $"; |
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#endif |
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/* |
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* Routines for handling BSDF data |
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*/ |
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#include "standard.h" |
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#include "bsdf.h" |
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#include "paths.h" |
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#include "ezxml.h" |
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#include <ctype.h> |
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#define MAXLATS 46 /* maximum number of latitudes */ |
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/* BSDF angle specification */ |
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typedef struct { |
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char name[64]; /* basis name */ |
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int nangles; /* total number of directions */ |
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struct { |
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float tmin; /* starting theta */ |
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short nphis; /* number of phis (0 term) */ |
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} lat[MAXLATS+1]; /* latitudes */ |
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} ANGLE_BASIS; |
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#define MAXABASES 3 /* limit on defined bases */ |
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static ANGLE_BASIS abase_list[MAXABASES] = { |
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{ |
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"LBNL/Klems Full", 145, |
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{ {-5., 1}, |
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{5., 8}, |
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{15., 16}, |
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{25., 20}, |
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{35., 24}, |
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{45., 24}, |
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{55., 24}, |
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{65., 16}, |
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{75., 12}, |
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{90., 0} } |
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}, { |
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"LBNL/Klems Half", 73, |
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{ {-6.5, 1}, |
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{6.5, 8}, |
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{19.5, 12}, |
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{32.5, 16}, |
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{46.5, 20}, |
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{61.5, 12}, |
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{76.5, 4}, |
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{90., 0} } |
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}, { |
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"LBNL/Klems Quarter", 41, |
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{ {-9., 1}, |
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{9., 8}, |
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{27., 12}, |
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{46., 12}, |
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{66., 8}, |
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{90., 0} } |
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} |
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}; |
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static int nabases = 3; /* current number of defined bases */ |
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static int |
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ab_getvec( /* get vector for this angle basis index */ |
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FVECT v, |
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int ndx, |
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void *p |
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) |
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{ |
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ANGLE_BASIS *ab = (ANGLE_BASIS *)p; |
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int li; |
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double alt, azi, d; |
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if ((ndx < 0) | (ndx >= ab->nangles)) |
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return(0); |
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for (li = 0; ndx >= ab->lat[li].nphis; li++) |
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ndx -= ab->lat[li].nphis; |
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alt = PI/180.*0.5*(ab->lat[li].tmin + ab->lat[li+1].tmin); |
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azi = 2.*PI*ndx/ab->lat[li].nphis; |
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v[2] = d = cos(alt); |
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d = sqrt(1. - d*d); /* sin(alt) */ |
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v[0] = cos(azi)*d; |
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v[1] = sin(azi)*d; |
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return(1); |
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} |
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static int |
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ab_getndx( /* get index corresponding to the given vector */ |
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FVECT v, |
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void *p |
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) |
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{ |
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ANGLE_BASIS *ab = (ANGLE_BASIS *)p; |
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int li, ndx; |
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double alt, azi, d; |
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if ((v[2] < -1.0) | (v[2] > 1.0)) |
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return(-1); |
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alt = 180.0/PI*acos(v[2]); |
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azi = 180.0/PI*atan2(v[1], v[0]); |
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if (azi < 0.0) azi += 360.0; |
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for (li = 1; ab->lat[li].tmin <= alt; li++) |
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if (!ab->lat[li].nphis) |
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return(-1); |
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--li; |
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ndx = (int)((1./360.)*azi*ab->lat[li].nphis + 0.5); |
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if (ndx >= ab->lat[li].nphis) ndx = 0; |
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while (li--) |
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ndx += ab->lat[li].nphis; |
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return(ndx); |
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} |
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static double |
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ab_getohm( /* get solid angle for this angle basis index */ |
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int ndx, |
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void *p |
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) |
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{ |
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ANGLE_BASIS *ab = (ANGLE_BASIS *)p; |
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int li; |
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double theta, theta1; |
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if ((ndx < 0) | (ndx >= ab->nangles)) |
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return(0); |
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for (li = 0; ndx >= ab->lat[li].nphis; li++) |
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ndx -= ab->lat[li].nphis; |
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theta1 = PI/180. * ab->lat[li+1].tmin; |
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if (ab->lat[li].nphis == 1) { /* special case */ |
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if (ab->lat[li].tmin > FTINY) |
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error(USER, "unsupported BSDF coordinate system"); |
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return(2.*PI*(1. - cos(theta1))); |
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} |
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theta = PI/180. * ab->lat[li].tmin; |
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return(2.*PI*(cos(theta) - cos(theta1))/(double)ab->lat[li].nphis); |
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} |
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static int |
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ab_getvecR( /* get reverse vector for this angle basis index */ |
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FVECT v, |
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int ndx, |
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void *p |
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) |
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{ |
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if (!ab_getvec(v, ndx, p)) |
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return(0); |
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v[0] = -v[0]; |
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v[1] = -v[1]; |
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v[2] = -v[2]; |
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return(1); |
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} |
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static int |
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ab_getndxR( /* get index corresponding to the reverse vector */ |
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FVECT v, |
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void *p |
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) |
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{ |
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FVECT v2; |
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v2[0] = -v[0]; |
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v2[1] = -v[1]; |
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v2[2] = -v[2]; |
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return ab_getndx(v2, p); |
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} |
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static void |
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load_bsdf_data( /* load BSDF distribution for this wavelength */ |
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struct BSDF_data *dp, |
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ezxml_t wdb |
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) |
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{ |
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char *cbasis = ezxml_txt(ezxml_child(wdb,"ColumnAngleBasis")); |
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char *rbasis = ezxml_txt(ezxml_child(wdb,"RowAngleBasis")); |
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char *sdata; |
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int i; |
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if ((cbasis == NULL) | (rbasis == NULL)) { |
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error(WARNING, "missing column/row basis for BSDF"); |
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return; |
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} |
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/* XXX need to add routines for loading in foreign bases */ |
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for (i = nabases; i--; ) |
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if (!strcmp(cbasis, abase_list[i].name)) { |
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dp->ninc = abase_list[i].nangles; |
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dp->ib_priv = (void *)&abase_list[i]; |
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dp->ib_vec = ab_getvecR; |
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dp->ib_ndx = ab_getndxR; |
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dp->ib_ohm = ab_getohm; |
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break; |
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} |
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if (i < 0) { |
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sprintf(errmsg, "unsupported ColumnAngleBasis '%s'", cbasis); |
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error(WARNING, errmsg); |
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return; |
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} |
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for (i = nabases; i--; ) |
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if (!strcmp(rbasis, abase_list[i].name)) { |
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dp->nout = abase_list[i].nangles; |
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dp->ob_priv = (void *)&abase_list[i]; |
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dp->ob_vec = ab_getvec; |
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dp->ob_ndx = ab_getndx; |
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dp->ob_ohm = ab_getohm; |
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break; |
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} |
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if (i < 0) { |
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sprintf(errmsg, "unsupported RowAngleBasis '%s'", cbasis); |
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error(WARNING, errmsg); |
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return; |
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} |
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/* read BSDF data */ |
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sdata = ezxml_txt(ezxml_child(wdb,"ScatteringData")); |
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if (sdata == NULL) { |
| 223 |
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error(WARNING, "missing BSDF ScatteringData"); |
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return; |
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} |
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dp->bsdf = (float *)malloc(sizeof(float)*dp->ninc*dp->nout); |
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if (dp->bsdf == NULL) |
| 228 |
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error(SYSTEM, "out of memory in load_bsdf_data"); |
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for (i = 0; i < dp->ninc*dp->nout; i++) { |
| 230 |
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char *sdnext = fskip(sdata); |
| 231 |
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if (sdnext == NULL) { |
| 232 |
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error(WARNING, "bad/missing BSDF ScatteringData"); |
| 233 |
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free(dp->bsdf); dp->bsdf = NULL; |
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return; |
| 235 |
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} |
| 236 |
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while (*sdnext && isspace(*sdnext)) |
| 237 |
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sdnext++; |
| 238 |
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if (*sdnext == ',') sdnext++; |
| 239 |
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dp->bsdf[i] = atof(sdata); |
| 240 |
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sdata = sdnext; |
| 241 |
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} |
| 242 |
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while (isspace(*sdata)) |
| 243 |
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sdata++; |
| 244 |
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if (*sdata) { |
| 245 |
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sprintf(errmsg, "%d extra characters after BSDF ScatteringData", |
| 246 |
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strlen(sdata)); |
| 247 |
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error(WARNING, errmsg); |
| 248 |
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} |
| 249 |
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} |
| 250 |
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static int |
| 253 |
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check_bsdf_data( /* check that BSDF data is sane */ |
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struct BSDF_data *dp |
| 255 |
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) |
| 256 |
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{ |
| 257 |
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double * omega_arr; |
| 258 |
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double dom, hemi_total; |
| 259 |
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int nneg; |
| 260 |
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int i, o; |
| 261 |
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| 262 |
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if (dp == NULL || dp->bsdf == NULL) |
| 263 |
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return(0); |
| 264 |
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omega_arr = (double *)calloc(dp->nout, sizeof(double)); |
| 265 |
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if (omega_arr == NULL) |
| 266 |
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error(SYSTEM, "out of memory in check_bsdf_data"); |
| 267 |
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hemi_total = .0; |
| 268 |
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for (o = dp->nout; o--; ) { |
| 269 |
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FVECT v; |
| 270 |
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dom = getBSDF_outohm(dp,o); |
| 271 |
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if (dom <= .0) { |
| 272 |
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error(WARNING, "zero/negative solid angle"); |
| 273 |
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continue; |
| 274 |
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} |
| 275 |
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if (!getBSDF_outvec(v,dp,o) || v[2] < -FTINY) { |
| 276 |
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error(WARNING, "illegal outgoing BSDF direction"); |
| 277 |
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free(omega_arr); |
| 278 |
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return(0); |
| 279 |
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} |
| 280 |
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hemi_total += omega_arr[o] = dom*v[2]; |
| 281 |
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} |
| 282 |
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if ((hemi_total > 1.02*PI) | (hemi_total < 0.98*PI)) { |
| 283 |
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sprintf(errmsg, "outgoing BSDF hemisphere off by %.1f%%", |
| 284 |
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100.*(hemi_total/PI - 1.)); |
| 285 |
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error(WARNING, errmsg); |
| 286 |
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} |
| 287 |
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dom = PI / hemi_total; /* normalize solid angles */ |
| 288 |
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for (o = dp->nout; o--; ) |
| 289 |
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omega_arr[o] *= dom; |
| 290 |
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nneg = 0; |
| 291 |
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for (i = dp->ninc; i--; ) { |
| 292 |
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hemi_total = .0; |
| 293 |
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for (o = dp->nout; o--; ) { |
| 294 |
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double f = BSDF_value(dp,i,o); |
| 295 |
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if (f > .0) |
| 296 |
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hemi_total += f*omega_arr[o]; |
| 297 |
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else if (f < -FTINY) |
| 298 |
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++nneg; |
| 299 |
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} |
| 300 |
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if (hemi_total > 1.02) { |
| 301 |
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sprintf(errmsg, "BSDF direction passes %.1f%% of light", |
| 302 |
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100.*hemi_total); |
| 303 |
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error(WARNING, errmsg); |
| 304 |
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} |
| 305 |
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} |
| 306 |
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free(omega_arr); |
| 307 |
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if (nneg > 0) { |
| 308 |
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sprintf(errmsg, "%d negative BSDF values", nneg); |
| 309 |
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error(WARNING, errmsg); |
| 310 |
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return(0); |
| 311 |
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} |
| 312 |
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return(1); |
| 313 |
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} |
| 314 |
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| 315 |
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struct BSDF_data * |
| 316 |
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load_BSDF( /* load BSDF data from file */ |
| 317 |
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char *fname |
| 318 |
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) |
| 319 |
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{ |
| 320 |
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char *path; |
| 321 |
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ezxml_t fl, wtl, wld, wdb; |
| 322 |
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struct BSDF_data *dp; |
| 323 |
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| 324 |
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path = getpath(fname, getrlibpath(), R_OK); |
| 325 |
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if (path == NULL) { |
| 326 |
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sprintf(errmsg, "cannot find BSDF file \"%s\"", fname); |
| 327 |
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error(WARNING, errmsg); |
| 328 |
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return(NULL); |
| 329 |
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} |
| 330 |
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fl = ezxml_parse_file(path); |
| 331 |
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if (fl == NULL) { |
| 332 |
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sprintf(errmsg, "cannot open BSDF \"%s\"", path); |
| 333 |
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error(WARNING, errmsg); |
| 334 |
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return(NULL); |
| 335 |
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} |
| 336 |
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if (ezxml_error(fl)[0]) { |
| 337 |
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sprintf(errmsg, "BSDF \"%s\" %s", path, ezxml_error(fl)); |
| 338 |
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error(WARNING, errmsg); |
| 339 |
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ezxml_free(fl); |
| 340 |
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return(NULL); |
| 341 |
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} |
| 342 |
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if (strcmp(ezxml_name(fl), "WindowElement")) { |
| 343 |
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sprintf(errmsg, |
| 344 |
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"BSDF \"%s\": top level node not 'WindowElement'", |
| 345 |
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path); |
| 346 |
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error(WARNING, errmsg); |
| 347 |
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ezxml_free(fl); |
| 348 |
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return(NULL); |
| 349 |
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} |
| 350 |
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wtl = ezxml_child(ezxml_child(fl, "Optical"), "Layer"); |
| 351 |
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dp = (struct BSDF_data *)calloc(1, sizeof(struct BSDF_data)); |
| 352 |
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for (wld = ezxml_child(wtl, "WavelengthData"); |
| 353 |
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wld != NULL; wld = wld->next) { |
| 354 |
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if (strcmp(ezxml_txt(ezxml_child(wld,"Wavelength")), "Visible")) |
| 355 |
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continue; |
| 356 |
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wdb = ezxml_child(wld, "WavelengthDataBlock"); |
| 357 |
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if (wdb == NULL) continue; |
| 358 |
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if (strcmp(ezxml_txt(ezxml_child(wdb,"WavelengthDataDirection")), |
| 359 |
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"Transmission Front")) |
| 360 |
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continue; |
| 361 |
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load_bsdf_data(dp, wdb); /* load front BTDF */ |
| 362 |
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break; /* ignore the rest */ |
| 363 |
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} |
| 364 |
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ezxml_free(fl); /* done with XML file */ |
| 365 |
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if (!check_bsdf_data(dp)) { |
| 366 |
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sprintf(errmsg, "bad/missing BTDF data in \"%s\"", path); |
| 367 |
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error(WARNING, errmsg); |
| 368 |
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free_BSDF(dp); |
| 369 |
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dp = NULL; |
| 370 |
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} |
| 371 |
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return(dp); |
| 372 |
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} |
| 373 |
|
|
|
| 374 |
|
|
|
| 375 |
|
|
void |
| 376 |
|
|
free_BSDF( /* free BSDF data structure */ |
| 377 |
|
|
struct BSDF_data *b |
| 378 |
|
|
) |
| 379 |
|
|
{ |
| 380 |
|
|
if (b == NULL) |
| 381 |
|
|
return; |
| 382 |
|
|
if (b->bsdf != NULL) |
| 383 |
|
|
free(b->bsdf); |
| 384 |
|
|
free(b); |
| 385 |
|
|
} |
| 386 |
|
|
|
| 387 |
|
|
|
| 388 |
|
|
int |
| 389 |
|
|
r_BSDF_incvec( /* compute random input vector at given location */ |
| 390 |
|
|
FVECT v, |
| 391 |
|
|
struct BSDF_data *b, |
| 392 |
|
|
int i, |
| 393 |
|
|
double rv, |
| 394 |
|
|
MAT4 xm |
| 395 |
|
|
) |
| 396 |
|
|
{ |
| 397 |
|
|
FVECT pert; |
| 398 |
|
|
double rad; |
| 399 |
|
|
int j; |
| 400 |
|
|
|
| 401 |
|
|
if (!getBSDF_incvec(v, b, i)) |
| 402 |
|
|
return(0); |
| 403 |
|
|
rad = sqrt(getBSDF_incohm(b, i) / PI); |
| 404 |
|
|
multisamp(pert, 3, rv); |
| 405 |
|
|
for (j = 0; j < 3; j++) |
| 406 |
|
|
v[j] += rad*(2.*pert[j] - 1.); |
| 407 |
|
|
if (xm != NULL) |
| 408 |
|
|
multv3(v, v, xm); |
| 409 |
|
|
return(normalize(v) != 0.0); |
| 410 |
|
|
} |
| 411 |
|
|
|
| 412 |
|
|
|
| 413 |
|
|
int |
| 414 |
|
|
r_BSDF_outvec( /* compute random output vector at given location */ |
| 415 |
|
|
FVECT v, |
| 416 |
|
|
struct BSDF_data *b, |
| 417 |
|
|
int o, |
| 418 |
|
|
double rv, |
| 419 |
|
|
MAT4 xm |
| 420 |
|
|
) |
| 421 |
|
|
{ |
| 422 |
|
|
FVECT pert; |
| 423 |
|
|
double rad; |
| 424 |
|
|
int j; |
| 425 |
|
|
|
| 426 |
|
|
if (!getBSDF_outvec(v, b, o)) |
| 427 |
|
|
return(0); |
| 428 |
|
|
rad = sqrt(getBSDF_outohm(b, o) / PI); |
| 429 |
|
|
multisamp(pert, 3, rv); |
| 430 |
|
|
for (j = 0; j < 3; j++) |
| 431 |
|
|
v[j] += rad*(2.*pert[j] - 1.); |
| 432 |
|
|
if (xm != NULL) |
| 433 |
|
|
multv3(v, v, xm); |
| 434 |
|
|
return(normalize(v) != 0.0); |
| 435 |
|
|
} |
| 436 |
|
|
|
| 437 |
|
|
|
| 438 |
|
|
#define FEQ(a,b) ((a)-(b) <= 1e-7 && (b)-(a) <= 1e-7) |
| 439 |
|
|
|
| 440 |
|
|
static int |
| 441 |
|
|
addrot( /* compute rotation (x,y,z) => (xp,yp,zp) */ |
| 442 |
|
|
char *xfarg[], |
| 443 |
|
|
FVECT xp, |
| 444 |
|
|
FVECT yp, |
| 445 |
|
|
FVECT zp |
| 446 |
|
|
) |
| 447 |
|
|
{ |
| 448 |
|
|
static char bufs[3][16]; |
| 449 |
|
|
int bn = 0; |
| 450 |
|
|
char **xfp = xfarg; |
| 451 |
|
|
double theta; |
| 452 |
|
|
|
| 453 |
|
|
if (yp[2]*yp[2] + zp[2]*zp[2] < 2.*FTINY*FTINY) { |
| 454 |
|
|
/* Special case for X' along Z-axis */ |
| 455 |
|
|
theta = -atan2(yp[0], yp[1]); |
| 456 |
|
|
*xfp++ = "-ry"; |
| 457 |
|
|
*xfp++ = xp[2] < 0.0 ? "90" : "-90"; |
| 458 |
|
|
*xfp++ = "-rz"; |
| 459 |
|
|
sprintf(bufs[bn], "%f", theta*(180./PI)); |
| 460 |
|
|
*xfp++ = bufs[bn++]; |
| 461 |
|
|
return(xfp - xfarg); |
| 462 |
|
|
} |
| 463 |
|
|
theta = atan2(yp[2], zp[2]); |
| 464 |
|
|
if (!FEQ(theta,0.0)) { |
| 465 |
|
|
*xfp++ = "-rx"; |
| 466 |
|
|
sprintf(bufs[bn], "%f", theta*(180./PI)); |
| 467 |
|
|
*xfp++ = bufs[bn++]; |
| 468 |
|
|
} |
| 469 |
|
|
theta = asin(-xp[2]); |
| 470 |
|
|
if (!FEQ(theta,0.0)) { |
| 471 |
|
|
*xfp++ = "-ry"; |
| 472 |
|
|
sprintf(bufs[bn], " %f", theta*(180./PI)); |
| 473 |
|
|
*xfp++ = bufs[bn++]; |
| 474 |
|
|
} |
| 475 |
|
|
theta = atan2(xp[1], xp[0]); |
| 476 |
|
|
if (!FEQ(theta,0.0)) { |
| 477 |
|
|
*xfp++ = "-rz"; |
| 478 |
|
|
sprintf(bufs[bn], "%f", theta*(180./PI)); |
| 479 |
|
|
*xfp++ = bufs[bn++]; |
| 480 |
|
|
} |
| 481 |
|
|
*xfp = NULL; |
| 482 |
|
|
return(xfp - xfarg); |
| 483 |
|
|
} |
| 484 |
|
|
|
| 485 |
|
|
|
| 486 |
|
|
int |
| 487 |
|
|
getBSDF_xfm( /* compute BSDF orient. -> world orient. transform */ |
| 488 |
|
|
MAT4 xm, |
| 489 |
|
|
FVECT nrm, |
| 490 |
|
|
UpDir ud |
| 491 |
|
|
) |
| 492 |
|
|
{ |
| 493 |
|
|
char *xfargs[7]; |
| 494 |
|
|
XF myxf; |
| 495 |
|
|
FVECT updir, xdest, ydest; |
| 496 |
|
|
|
| 497 |
|
|
updir[0] = updir[1] = updir[2] = 0.; |
| 498 |
|
|
switch (ud) { |
| 499 |
|
|
case UDzneg: |
| 500 |
|
|
updir[2] = -1.; |
| 501 |
|
|
break; |
| 502 |
|
|
case UDyneg: |
| 503 |
|
|
updir[1] = -1.; |
| 504 |
|
|
break; |
| 505 |
|
|
case UDxneg: |
| 506 |
|
|
updir[0] = -1.; |
| 507 |
|
|
break; |
| 508 |
|
|
case UDxpos: |
| 509 |
|
|
updir[0] = 1.; |
| 510 |
|
|
break; |
| 511 |
|
|
case UDypos: |
| 512 |
|
|
updir[1] = 1.; |
| 513 |
|
|
break; |
| 514 |
|
|
case UDzpos: |
| 515 |
|
|
updir[2] = 1.; |
| 516 |
|
|
break; |
| 517 |
|
|
case UDunknown: |
| 518 |
|
|
return(0); |
| 519 |
|
|
} |
| 520 |
|
|
fcross(xdest, updir, nrm); |
| 521 |
|
|
if (normalize(xdest) == 0.0) |
| 522 |
|
|
return(0); |
| 523 |
|
|
fcross(ydest, nrm, xdest); |
| 524 |
|
|
xf(&myxf, addrot(xfargs, xdest, ydest, nrm), xfargs); |
| 525 |
|
|
copymat4(xm, myxf.xfm); |
| 526 |
|
|
return(1); |
| 527 |
|
|
} |
