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#ifndef lint
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static const char RCSid[] = "$Id: mkillum4.c,v 2.18 2009/06/06 05:03:47 greg Exp $";
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#endif
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/*
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* Routines for handling BSDF data within mkillum
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*/
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#include "mkillum.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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#ifndef NBSDFSAMPS
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#define NBSDFSAMPS 32 /* BSDF resampling count */
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#endif
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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) {
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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)
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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++) {
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char *sdnext = fskip(sdata);
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if (sdnext == NULL) {
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error(WARNING, "bad/missing BSDF ScatteringData");
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free(dp->bsdf); dp->bsdf = NULL;
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return;
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}
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while (*sdnext && isspace(*sdnext))
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sdnext++;
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if (*sdnext == ',') sdnext++;
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dp->bsdf[i] = atof(sdata);
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sdata = sdnext;
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}
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while (isspace(*sdata))
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sdata++;
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if (*sdata) {
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sprintf(errmsg, "%d extra characters after BSDF ScatteringData",
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strlen(sdata));
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error(WARNING, errmsg);
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}
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}
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static int
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check_bsdf_data( /* check that BSDF data is sane */
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struct BSDF_data *dp
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)
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{
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double * omega_arr;
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double dom, hemi_total;
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int nneg;
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int i, o;
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if (dp == NULL || dp->bsdf == NULL)
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return(0);
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omega_arr = (double *)calloc(dp->nout, sizeof(double));
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if (omega_arr == NULL)
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error(SYSTEM, "out of memory in check_bsdf_data");
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hemi_total = .0;
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for (o = dp->nout; o--; ) {
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FVECT v;
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dom = getBSDF_outohm(dp,o);
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if (dom <= .0) {
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error(WARNING, "zero/negative solid angle");
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continue;
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}
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if (!getBSDF_outvec(v,dp,o) || v[2] < -FTINY) {
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error(WARNING, "illegal outgoing BSDF direction");
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free(omega_arr);
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return(0);
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}
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hemi_total += omega_arr[o] = dom*v[2];
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}
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if ((hemi_total > 1.02*PI) | (hemi_total < 0.98*PI)) {
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sprintf(errmsg, "outgoing BSDF hemisphere off by %.1f%%",
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100.*(hemi_total/PI - 1.));
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error(WARNING, errmsg);
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}
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dom = PI / hemi_total; /* normalize solid angles */
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for (o = dp->nout; o--; )
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omega_arr[o] *= dom;
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nneg = 0;
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for (i = dp->ninc; i--; ) {
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hemi_total = .0;
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for (o = dp->nout; o--; ) {
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double f = BSDF_value(dp,i,o);
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if (f > .0)
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hemi_total += f*omega_arr[o];
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else if (f < -FTINY)
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++nneg;
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}
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if (hemi_total > 1.02) {
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sprintf(errmsg, "BSDF direction passes %.1f%% of light",
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100.*hemi_total);
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error(WARNING, errmsg);
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}
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}
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free(omega_arr);
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if (nneg > 0) {
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sprintf(errmsg, "%d negative BSDF values", nneg);
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error(WARNING, errmsg);
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return(0);
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}
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return(1);
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}
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struct BSDF_data *
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load_BSDF( /* load BSDF data from file */
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char *fname
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| 320 |
)
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| 321 |
{
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| 322 |
char *path;
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| 323 |
ezxml_t fl, wtl, wld, wdb;
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| 324 |
struct BSDF_data *dp;
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| 325 |
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| 326 |
path = getpath(fname, getrlibpath(), R_OK);
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| 327 |
if (path == NULL) {
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| 328 |
sprintf(errmsg, "cannot find BSDF file \"%s\"", fname);
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error(WARNING, errmsg);
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| 330 |
return(NULL);
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| 331 |
}
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| 332 |
fl = ezxml_parse_file(path);
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| 333 |
if (fl == NULL) {
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| 334 |
sprintf(errmsg, "cannot open BSDF \"%s\"", path);
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| 335 |
error(WARNING, errmsg);
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| 336 |
return(NULL);
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| 337 |
}
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| 338 |
if (ezxml_error(fl)[0]) {
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| 339 |
sprintf(errmsg, "BSDF \"%s\" %s", path, ezxml_error(fl));
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| 340 |
error(WARNING, errmsg);
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| 341 |
ezxml_free(fl);
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| 342 |
return(NULL);
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| 343 |
}
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| 344 |
if (strcmp(ezxml_name(fl), "WindowElement")) {
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| 345 |
sprintf(errmsg,
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| 346 |
"BSDF \"%s\": top level node not 'WindowElement'",
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| 347 |
path);
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| 348 |
error(WARNING, errmsg);
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| 349 |
ezxml_free(fl);
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| 350 |
return(NULL);
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| 351 |
}
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| 352 |
wtl = ezxml_child(ezxml_child(fl, "Optical"), "Layer");
|
| 353 |
dp = (struct BSDF_data *)calloc(1, sizeof(struct BSDF_data));
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| 354 |
for (wld = ezxml_child(wtl, "WavelengthData");
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| 355 |
wld != NULL; wld = wld->next) {
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| 356 |
if (strcmp(ezxml_txt(ezxml_child(wld,"Wavelength")), "Visible"))
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| 357 |
continue;
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| 358 |
wdb = ezxml_child(wld, "WavelengthDataBlock");
|
| 359 |
if (wdb == NULL) continue;
|
| 360 |
if (strcmp(ezxml_txt(ezxml_child(wdb,"WavelengthDataDirection")),
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| 361 |
"Transmission Front"))
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| 362 |
continue;
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| 363 |
load_bsdf_data(dp, wdb); /* load front BTDF */
|
| 364 |
break; /* ignore the rest */
|
| 365 |
}
|
| 366 |
ezxml_free(fl); /* done with XML file */
|
| 367 |
if (!check_bsdf_data(dp)) {
|
| 368 |
sprintf(errmsg, "bad/missing BTDF data in \"%s\"", path);
|
| 369 |
error(WARNING, errmsg);
|
| 370 |
free_BSDF(dp);
|
| 371 |
dp = NULL;
|
| 372 |
}
|
| 373 |
return(dp);
|
| 374 |
}
|
| 375 |
|
| 376 |
|
| 377 |
void
|
| 378 |
free_BSDF( /* free BSDF data structure */
|
| 379 |
struct BSDF_data *b
|
| 380 |
)
|
| 381 |
{
|
| 382 |
if (b == NULL)
|
| 383 |
return;
|
| 384 |
if (b->bsdf != NULL)
|
| 385 |
free(b->bsdf);
|
| 386 |
free(b);
|
| 387 |
}
|
| 388 |
|
| 389 |
|
| 390 |
int
|
| 391 |
r_BSDF_incvec( /* compute random input vector at given location */
|
| 392 |
FVECT v,
|
| 393 |
struct BSDF_data *b,
|
| 394 |
int i,
|
| 395 |
double rv,
|
| 396 |
MAT4 xm
|
| 397 |
)
|
| 398 |
{
|
| 399 |
FVECT pert;
|
| 400 |
double rad;
|
| 401 |
int j;
|
| 402 |
|
| 403 |
if (!getBSDF_incvec(v, b, i))
|
| 404 |
return(0);
|
| 405 |
rad = sqrt(getBSDF_incohm(b, i) / PI);
|
| 406 |
multisamp(pert, 3, rv);
|
| 407 |
for (j = 0; j < 3; j++)
|
| 408 |
v[j] += rad*(2.*pert[j] - 1.);
|
| 409 |
if (xm != NULL)
|
| 410 |
multv3(v, v, xm);
|
| 411 |
return(normalize(v) != 0.0);
|
| 412 |
}
|
| 413 |
|
| 414 |
|
| 415 |
int
|
| 416 |
r_BSDF_outvec( /* compute random output vector at given location */
|
| 417 |
FVECT v,
|
| 418 |
struct BSDF_data *b,
|
| 419 |
int o,
|
| 420 |
double rv,
|
| 421 |
MAT4 xm
|
| 422 |
)
|
| 423 |
{
|
| 424 |
FVECT pert;
|
| 425 |
double rad;
|
| 426 |
int j;
|
| 427 |
|
| 428 |
if (!getBSDF_outvec(v, b, o))
|
| 429 |
return(0);
|
| 430 |
rad = sqrt(getBSDF_outohm(b, o) / PI);
|
| 431 |
multisamp(pert, 3, rv);
|
| 432 |
for (j = 0; j < 3; j++)
|
| 433 |
v[j] += rad*(2.*pert[j] - 1.);
|
| 434 |
if (xm != NULL)
|
| 435 |
multv3(v, v, xm);
|
| 436 |
return(normalize(v) != 0.0);
|
| 437 |
}
|
| 438 |
|
| 439 |
|
| 440 |
#define FEQ(a,b) ((a)-(b) <= 1e-7 && (b)-(a) <= 1e-7)
|
| 441 |
|
| 442 |
static int
|
| 443 |
addrot( /* compute rotation (x,y,z) => (xp,yp,zp) */
|
| 444 |
char *xfarg[],
|
| 445 |
FVECT xp,
|
| 446 |
FVECT yp,
|
| 447 |
FVECT zp
|
| 448 |
)
|
| 449 |
{
|
| 450 |
static char bufs[3][16];
|
| 451 |
int bn = 0;
|
| 452 |
char **xfp = xfarg;
|
| 453 |
double theta;
|
| 454 |
|
| 455 |
if (yp[2]*yp[2] + zp[2]*zp[2] < 2.*FTINY*FTINY) {
|
| 456 |
/* Special case for X' along Z-axis */
|
| 457 |
theta = -atan2(yp[0], yp[1]);
|
| 458 |
*xfp++ = "-ry";
|
| 459 |
*xfp++ = xp[2] < 0.0 ? "90" : "-90";
|
| 460 |
*xfp++ = "-rz";
|
| 461 |
sprintf(bufs[bn], "%f", theta*(180./PI));
|
| 462 |
*xfp++ = bufs[bn++];
|
| 463 |
return(xfp - xfarg);
|
| 464 |
}
|
| 465 |
theta = atan2(yp[2], zp[2]);
|
| 466 |
if (!FEQ(theta,0.0)) {
|
| 467 |
*xfp++ = "-rx";
|
| 468 |
sprintf(bufs[bn], "%f", theta*(180./PI));
|
| 469 |
*xfp++ = bufs[bn++];
|
| 470 |
}
|
| 471 |
theta = asin(-xp[2]);
|
| 472 |
if (!FEQ(theta,0.0)) {
|
| 473 |
*xfp++ = "-ry";
|
| 474 |
sprintf(bufs[bn], " %f", theta*(180./PI));
|
| 475 |
*xfp++ = bufs[bn++];
|
| 476 |
}
|
| 477 |
theta = atan2(xp[1], xp[0]);
|
| 478 |
if (!FEQ(theta,0.0)) {
|
| 479 |
*xfp++ = "-rz";
|
| 480 |
sprintf(bufs[bn], "%f", theta*(180./PI));
|
| 481 |
*xfp++ = bufs[bn++];
|
| 482 |
}
|
| 483 |
*xfp = NULL;
|
| 484 |
return(xfp - xfarg);
|
| 485 |
}
|
| 486 |
|
| 487 |
|
| 488 |
int
|
| 489 |
getBSDF_xfm( /* compute BSDF orient. -> world orient. transform */
|
| 490 |
MAT4 xm,
|
| 491 |
FVECT nrm,
|
| 492 |
UpDir ud
|
| 493 |
)
|
| 494 |
{
|
| 495 |
char *xfargs[7];
|
| 496 |
XF myxf;
|
| 497 |
FVECT updir, xdest, ydest;
|
| 498 |
|
| 499 |
updir[0] = updir[1] = updir[2] = 0.;
|
| 500 |
switch (ud) {
|
| 501 |
case UDzneg:
|
| 502 |
updir[2] = -1.;
|
| 503 |
break;
|
| 504 |
case UDyneg:
|
| 505 |
updir[1] = -1.;
|
| 506 |
break;
|
| 507 |
case UDxneg:
|
| 508 |
updir[0] = -1.;
|
| 509 |
break;
|
| 510 |
case UDxpos:
|
| 511 |
updir[0] = 1.;
|
| 512 |
break;
|
| 513 |
case UDypos:
|
| 514 |
updir[1] = 1.;
|
| 515 |
break;
|
| 516 |
case UDzpos:
|
| 517 |
updir[2] = 1.;
|
| 518 |
break;
|
| 519 |
case UDunknown:
|
| 520 |
return(0);
|
| 521 |
}
|
| 522 |
fcross(xdest, updir, nrm);
|
| 523 |
if (normalize(xdest) == 0.0)
|
| 524 |
return(0);
|
| 525 |
fcross(ydest, nrm, xdest);
|
| 526 |
xf(&myxf, addrot(xfargs, xdest, ydest, nrm), xfargs);
|
| 527 |
copymat4(xm, myxf.xfm);
|
| 528 |
return(1);
|
| 529 |
}
|
| 530 |
|
| 531 |
|
| 532 |
void
|
| 533 |
redistribute( /* pass distarr ray sums through BSDF */
|
| 534 |
struct BSDF_data *b,
|
| 535 |
int nalt,
|
| 536 |
int nazi,
|
| 537 |
FVECT u,
|
| 538 |
FVECT v,
|
| 539 |
FVECT w,
|
| 540 |
MAT4 xm
|
| 541 |
)
|
| 542 |
{
|
| 543 |
int nout = 0;
|
| 544 |
MAT4 mymat, inmat;
|
| 545 |
COLORV *idist;
|
| 546 |
COLORV *cp;
|
| 547 |
FVECT dv;
|
| 548 |
double wt;
|
| 549 |
int i, j, k, c, o;
|
| 550 |
COLOR col, cinc;
|
| 551 |
/* copy incoming distribution */
|
| 552 |
if (b->ninc > distsiz)
|
| 553 |
error(INTERNAL, "error 1 in redistribute");
|
| 554 |
idist = (COLORV *)malloc(sizeof(COLOR)*b->ninc);
|
| 555 |
if (idist == NULL)
|
| 556 |
error(SYSTEM, "out of memory in redistribute");
|
| 557 |
memcpy(idist, distarr, sizeof(COLOR)*b->ninc);
|
| 558 |
/* compose direction transform */
|
| 559 |
for (i = 3; i--; ) {
|
| 560 |
mymat[i][0] = u[i];
|
| 561 |
mymat[i][1] = v[i];
|
| 562 |
mymat[i][2] = w[i];
|
| 563 |
mymat[i][3] = 0.;
|
| 564 |
}
|
| 565 |
mymat[3][0] = mymat[3][1] = mymat[3][2] = 0.;
|
| 566 |
mymat[3][3] = 1.;
|
| 567 |
if (xm != NULL)
|
| 568 |
multmat4(mymat, xm, mymat);
|
| 569 |
for (i = 3; i--; ) { /* make sure it's normalized */
|
| 570 |
wt = 1./sqrt( mymat[0][i]*mymat[0][i] +
|
| 571 |
mymat[1][i]*mymat[1][i] +
|
| 572 |
mymat[2][i]*mymat[2][i] );
|
| 573 |
for (j = 3; j--; )
|
| 574 |
mymat[j][i] *= wt;
|
| 575 |
}
|
| 576 |
if (!invmat4(inmat, mymat)) /* need inverse as well */
|
| 577 |
error(INTERNAL, "cannot invert BSDF transform");
|
| 578 |
newdist(nalt*nazi); /* resample distribution */
|
| 579 |
for (i = b->ninc; i--; ) {
|
| 580 |
int direct_out = -1;
|
| 581 |
COLOR cdir;
|
| 582 |
getBSDF_incvec(dv, b, i); /* compute incident irrad. */
|
| 583 |
multv3(dv, dv, mymat);
|
| 584 |
if (dv[2] < 0.0) {
|
| 585 |
dv[0] = -dv[0]; dv[1] = -dv[1]; dv[2] = -dv[2];
|
| 586 |
direct_out += (direct_discount != NULL);
|
| 587 |
}
|
| 588 |
wt = getBSDF_incohm(b, i);
|
| 589 |
wt *= dv[2]; /* solid_angle*cosine(theta) */
|
| 590 |
cp = &idist[3*i];
|
| 591 |
copycolor(cinc, cp);
|
| 592 |
scalecolor(cinc, wt);
|
| 593 |
if (!direct_out) { /* discount direct contr. */
|
| 594 |
cp = &direct_discount[3*i];
|
| 595 |
copycolor(cdir, cp);
|
| 596 |
scalecolor(cdir, -wt);
|
| 597 |
direct_out = flatindex(dv, nalt, nazi);
|
| 598 |
}
|
| 599 |
for (k = nalt; k--; ) /* loop over distribution */
|
| 600 |
for (j = nazi; j--; ) {
|
| 601 |
int rstart = random();
|
| 602 |
for (c = NBSDFSAMPS; c--; ) {
|
| 603 |
double sp[2];
|
| 604 |
multisamp(sp, 2, urand(rstart+c));
|
| 605 |
flatdir(dv, (k + sp[0])/nalt,
|
| 606 |
(j + .5 - sp[1])/nazi);
|
| 607 |
multv3(dv, dv, inmat);
|
| 608 |
/* evaluate BSDF @ outgoing */
|
| 609 |
o = getBSDF_outndx(b, dv);
|
| 610 |
if (o < 0) {
|
| 611 |
nout++;
|
| 612 |
continue;
|
| 613 |
}
|
| 614 |
wt = BSDF_value(b, i, o) * (1./NBSDFSAMPS);
|
| 615 |
copycolor(col, cinc);
|
| 616 |
o = k*nazi + j;
|
| 617 |
if (o == direct_out)
|
| 618 |
addcolor(col, cdir); /* minus direct */
|
| 619 |
scalecolor(col, wt);
|
| 620 |
cp = &distarr[3*o];
|
| 621 |
addcolor(cp, col); /* sum into distribution */
|
| 622 |
}
|
| 623 |
}
|
| 624 |
}
|
| 625 |
free(idist); /* free temp space */
|
| 626 |
if (nout) {
|
| 627 |
sprintf(errmsg, "missing %.1f%% of BSDF directions",
|
| 628 |
100.*nout/(b->ninc*nalt*nazi*NBSDFSAMPS));
|
| 629 |
error(WARNING, errmsg);
|
| 630 |
}
|
| 631 |
}
|
