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#ifndef lint |
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static const char RCSid[] = "$Id: bsdfpeaks.c,v 2.1 2025/05/21 17:23:07 greg Exp $"; |
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#endif |
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/* |
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* Compute minimum FWHM peak for each incident direction in SIR input. |
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* Report FWHM of corresponding peaks in XML representations if provided. |
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*/ |
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|
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#define _USE_MATH_DEFINES |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <math.h> |
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#include "bsdfrep.h" |
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|
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typedef struct { |
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float peakv; /* peak BSDF value */ |
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float width; /* smallest FWHM (deg) */ |
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RBFNODE *rbs; /* incident system */ |
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int ndx; /* peak index for RBFVAL */ |
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} FWHM; /* struct to hold peak value */ |
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|
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typedef double eval_f(const FVECT vin, const FVECT vout, const void *p); |
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|
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char *progname; /* needed by bsdfrep.c */ |
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|
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/* Comparison function to put larger peaks first */ |
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int |
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cmpFWHM(const void *p0, const void *p1) |
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{ |
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float diff = (*(const FWHM *)p0).peakv - |
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(*(const FWHM *)p1).peakv; |
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|
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if (diff > 0) return(-1); |
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if (diff < 0) return(1); |
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return(0); |
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} |
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|
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/* BSDF evaluation function for RBF system */ |
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double |
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rbf_eval(const FVECT vin, const FVECT vout, const void *p) |
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{ |
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/* XXX verify vin == p->invec ? */ |
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return(eval_rbfrep((const RBFNODE *)p, vout)); |
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} |
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|
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/* BSDF evaluation for XML input */ |
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double |
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bsdf_eval(const FVECT vin, const FVECT vout, const void *p) |
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{ |
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SDValue sv; |
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|
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if (SDreportError( |
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SDevalBSDF(&sv, vin, vout, (const SDData *)p), |
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stderr)) |
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exit(1); |
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|
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return(sv.cieY); |
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} |
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|
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/* Find full-width, half-maximum in radians around BSDF direction */ |
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double |
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getFWHM(const FVECT vin, const FVECT vc, double rad0, eval_f *ev, const void *p) |
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{ |
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const double peakv = (*ev)(vin, vc, p); |
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double rad1 = rad0; /* current radii */ |
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|
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while (rad0 < M_PI/2.) { /* look for FWHM */ |
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FVECT v0, vt; |
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double phi; |
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v0[0] = 1; v0[1] = v0[2] = 0; |
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geodesic(v0, vc, v0, rad0, GEOD_RAD); /* use vc as pivot */ |
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for (phi = 0; phi < 2.*M_PI; phi += M_PI/18.) { |
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spinvector(vt, v0, vc, phi); |
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if ((*ev)(vin, vt, p) <= .5*peakv) { /* found one side? */ |
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FVECT vt1; |
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while (rad1 < M_PI/2.) { /* bracket peak */ |
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geodesic(vt1, vt, vc, rad0+rad1, GEOD_RAD); |
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if ((*ev)(vin, vt1, p) <= .5*peakv) |
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return(rad0+rad1); /* got both! */ |
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rad1 *= 1.05; /* else bump rad1 */ |
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} |
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} |
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} |
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rad1 = rad0 *= 1.05; /* or expand search */ |
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} |
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return(M_PI); /* failure return */ |
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} |
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|
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/* Get outgoing direction for the given FWHM record */ |
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void |
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getOutDir(FVECT vo, FWHM *dp) |
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{ |
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RBFVAL *vp = dp->rbs->rbfa + dp->ndx; |
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|
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ovec_from_pos(vo, vp->gx, vp->gy); |
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} |
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|
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/* Assign FWHM record for specified RBF system */ |
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void |
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assignFWHM(FWHM *dp, RBFNODE *rbf) |
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{ |
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FVECT vo; |
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int j; |
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double rad; |
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|
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dp->rbs = rbf; |
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dp->ndx = 0; /* find peak outgoing */ |
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for (j = rbf->nrbf; --j; ) |
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if (rbf->rbfa[j].peak > rbf->rbfa[dp->ndx].peak) |
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dp->ndx = j; |
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/* record peak */ |
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getOutDir(vo, dp); |
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dp->peakv = eval_rbfrep(rbf, vo); |
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/* get FWHM angle in degrees */ |
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dp->width = 180./M_PI * getFWHM(rbf->invec, vo, |
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R2ANG(rbf->rbfa[dp->ndx].crad), |
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rbf_eval, rbf); |
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} |
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|
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/* Evaluate FWHM for each incident direction recorded in SIR */ |
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int |
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main(int argc, char *argv[]) |
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{ |
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RBFNODE *rbf; |
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SDData *sdp; |
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FILE *fp; |
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int ndirs; |
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FWHM *peaka; |
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int i; |
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|
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progname = argv[0]; |
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if (argc < 2) |
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goto userr; |
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|
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fp = fopen(argv[1], "rb"); /* load SIR input */ |
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if (fp == NULL) { |
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fprintf(stderr, "%s: cannot open BSDF interpolant '%s'\n", |
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progname, argv[1]); |
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return(1); |
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} |
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if (!load_bsdf_rep(fp)) |
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return(1); |
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fclose(fp); |
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for (i = 2; i < argc; i++) /* check/load any XMLs */ |
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if (SDcacheFile(argv[i]) == NULL) |
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return(1); |
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ndirs = 0; /* count input directions */ |
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for (rbf = dsf_list; rbf != NULL; rbf = rbf->next) { |
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if (rbf->nrbf <= 0) { |
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ndirs = 0; |
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break; |
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} |
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++ndirs; |
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} |
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if (!ndirs) { |
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fprintf(stderr, "%s: missing/bad RBFs in '%s'\n", progname, argv[1]); |
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return(1); |
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} |
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/* print output header */ |
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printf("%d incident directions in '%s': %s -> %s\n", ndirs, argv[1], |
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input_orient>0 ? "Front" : "Back", |
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output_orient>0 ? "Front" : "Back"); |
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fputs("Incident (theta, phi)\tExiting (theta, phi)\tPeak\tFWHM", stdout); |
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for (i = 2; i < argc; i++) |
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printf("\t'%s'", argv[i]); |
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fputc('\n', stdout); |
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/* find SIR peaks */ |
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peaka = (FWHM *)malloc(sizeof(FWHM)*ndirs); |
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if (peaka == NULL) return(1); |
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for (i = 0, rbf = dsf_list; i < ndirs; i++, rbf = rbf->next) |
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assignFWHM(&peaka[i], rbf); |
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/* sort strong to weak */ |
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qsort(peaka, ndirs, sizeof(FWHM), cmpFWHM); |
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|
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for (i = 0; i < ndirs; i++) { /* report FWHM for each incidence */ |
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FVECT vout; |
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int j; |
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getOutDir(vout, &peaka[i]); |
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printf("%.0f %.0f\t%.0f %.0f", get_theta180(peaka[i].rbs->invec), |
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get_phi360(peaka[i].rbs->invec), |
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get_theta180(vout), get_phi360(vout)); |
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/* peak and FWHM from SIR */ |
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printf("\t%.2e\t%.1f", peaka[i].peakv, peaka[i].width); |
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/* FWHM for each XML */ |
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for (j = 2; j < argc; j++) { |
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const SDData *sd = SDcacheFile(argv[j]); |
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double psa; |
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if (SDreportError( |
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SDsizeBSDF(&psa, peaka[i].rbs->invec, |
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NULL, SDqueryMin, sd), |
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stderr)) |
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return(1); |
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|
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printf("\t%.1f", 180./M_PI * getFWHM(peaka[i].rbs->invec, |
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vout, sqrt(psa/M_PI), |
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bsdf_eval, sd)); |
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} |
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fputc('\n', stdout); |
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} |
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return(0); |
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userr: |
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fprintf(stderr, "Usage: %s bsdf.sir [bsdfrep1.xml ..]\n", progname); |
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return(1); |
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} |
