src/cv/bsdfrep.c

#ifndef lint
static const char RCSid[] = "$Id: bsdfrep.c,v 2.18 2013/11/08 05:37:20 greg Exp $";
#endif
/*
 * Support BSDF representation as radial basis functions.
 *
 *      G. Ward
 */

#define _USE_MATH_DEFINES
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "rtio.h"
#include "resolu.h"
#include "bsdfrep.h"
                                /* name and manufacturer if known */
char                    bsdf_name[256];
char                    bsdf_manuf[256];
                                /* active grid resolution */
int                     grid_res = GRIDRES;

                                /* coverage/symmetry using INP_QUAD? flags */
int                     inp_coverage = 0;
                                /* all incident angles in-plane so far? */
int                     single_plane_incident = -1;

                                /* input/output orientations */
int                     input_orient = 0;
int                     output_orient = 0;

                                /* BSDF histogram */
unsigned long           bsdf_hist[HISTLEN];

                                /* BSDF value for boundary regions */
double                  bsdf_min = 0;

                                /* processed incident DSF measurements */
RBFNODE                 *dsf_list = NULL;

                                /* RBF-linking matrices (edges) */
MIGRATION               *mig_list = NULL;

                                /* current input direction */
double                  theta_in_deg, phi_in_deg;

/* Register new input direction */
int
new_input_direction(double new_theta, double new_phi)
{
        if (!input_orient)              /* check input orientation */
                input_orient = 1 - 2*(new_theta > 90.);
        else if (input_orient > 0 ^ new_theta < 90.) {
                fprintf(stderr,
                "%s: Cannot handle input angles on both sides of surface\n",
                                progname);
                return(0);
        }
                                        /* normalize angle ranges */
        while (new_theta < -180.)
                new_theta += 360.;
        while (new_theta > 180.)
                new_theta -= 360.;
        if (new_theta < 0) {
                new_theta = -new_theta;
                new_phi += 180.;
        }
        if ((theta_in_deg = new_theta) < 1.0)
                return(1);              /* don't rely on phi near normal */
        while (new_phi < 0)
                new_phi += 360.;
        while (new_phi >= 360.)
                new_phi -= 360.;
        if (single_plane_incident > 0)  /* check input coverage */
                single_plane_incident = (round(new_phi) == round(phi_in_deg));
        else if (single_plane_incident < 0)
                single_plane_incident = 1;
        phi_in_deg = new_phi;
        if ((1. < new_phi) & (new_phi < 89.))
                inp_coverage |= INP_QUAD1;
        else if ((91. < new_phi) & (new_phi < 179.))
                inp_coverage |= INP_QUAD2;
        else if ((181. < new_phi) & (new_phi < 269.))
                inp_coverage |= INP_QUAD3;
        else if ((271. < new_phi) & (new_phi < 359.))
                inp_coverage |= INP_QUAD4;
        return(1);
}

/* Apply symmetry to the given vector based on distribution */
int
use_symmetry(FVECT vec)
{
        const double    phi = get_phi360(vec);

        switch (inp_coverage) {
        case INP_QUAD1|INP_QUAD2|INP_QUAD3|INP_QUAD4:
                break;
        case INP_QUAD1|INP_QUAD2:
                if ((-FTINY > phi) | (phi > 180.+FTINY))
                        goto mir_y;
                break;
        case INP_QUAD2|INP_QUAD3:
                if ((90.-FTINY > phi) | (phi > 270.+FTINY))
                        goto mir_x;
                break;
        case INP_QUAD3|INP_QUAD4:
                if ((180.-FTINY > phi) | (phi > 360.+FTINY))
                        goto mir_y;
                break;
        case INP_QUAD4|INP_QUAD1:
                if ((270.-FTINY > phi) & (phi > 90.+FTINY))
                        goto mir_x;
                break;
        case INP_QUAD1:
                if ((-FTINY > phi) | (phi > 90.+FTINY))
                        switch ((int)(phi*(1./90.))) {
                        case 1: goto mir_x;
                        case 2: goto mir_xy;
                        case 3: goto mir_y;
                        }
                break;
        case INP_QUAD2:
                if ((90.-FTINY > phi) | (phi > 180.+FTINY))
                        switch ((int)(phi*(1./90.))) {
                        case 0: goto mir_x;
                        case 2: goto mir_y;
                        case 3: goto mir_xy;
                        }
                break;
        case INP_QUAD3:
                if ((180.-FTINY > phi) | (phi > 270.+FTINY))
                        switch ((int)(phi*(1./90.))) {
                        case 0: goto mir_xy;
                        case 1: goto mir_y;
                        case 3: goto mir_x;
                        }
                break;
        case INP_QUAD4:
                if ((270.-FTINY > phi) | (phi > 360.+FTINY))
                        switch ((int)(phi*(1./90.))) {
                        case 0: goto mir_y;
                        case 1: goto mir_xy;
                        case 2: goto mir_x;
                        }
                break;
        default:
                fprintf(stderr, "%s: Illegal input coverage (%d)\n",
                                        progname, inp_coverage);
                exit(1);
        }
        return(0);              /* in range */
mir_x:
        vec[0] = -vec[0];
        return(MIRROR_X);
mir_y:
        vec[1] = -vec[1];
        return(MIRROR_Y);
mir_xy:
        vec[0] = -vec[0];
        vec[1] = -vec[1];
        return(MIRROR_X|MIRROR_Y);
}

/* Reverse symmetry based on what was done before */
void
rev_symmetry(FVECT vec, int sym)
{
        if (sym & MIRROR_X)
                vec[0] = -vec[0];
        if (sym & MIRROR_Y)
                vec[1] = -vec[1];
}

/* Reverse symmetry for an RBF distribution */
void
rev_rbf_symmetry(RBFNODE *rbf, int sym)
{
        int     n;

        rev_symmetry(rbf->invec, sym);
        if (sym & MIRROR_X)
                for (n = rbf->nrbf; n-- > 0; )
                        rbf->rbfa[n].gx = grid_res-1 - rbf->rbfa[n].gx;
        if (sym & MIRROR_Y)
                for (n = rbf->nrbf; n-- > 0; )
                        rbf->rbfa[n].gy = grid_res-1 - rbf->rbfa[n].gy;
}

/* Rotate RBF to correspond to given incident vector */
void
rotate_rbf(RBFNODE *rbf, const FVECT invec)
{
        static const FVECT      vnorm = {.0, .0, 1.};
        const double            phi = atan2(invec[1],invec[0]) -
                                        atan2(rbf->invec[1],rbf->invec[0]);
        FVECT                   outvec;
        int                     pos[2];
        int                     n;

        for (n = ((-.01 > phi) | (phi > .01))*rbf->nrbf; n-- > 0; ) {
                ovec_from_pos(outvec, rbf->rbfa[n].gx, rbf->rbfa[n].gy);
                spinvector(outvec, outvec, vnorm, phi);
                pos_from_vec(pos, outvec);
                rbf->rbfa[n].gx = pos[0];
                rbf->rbfa[n].gy = pos[1];
        }
        VCOPY(rbf->invec, invec);
}

/* Compute outgoing vector from grid position */
void
ovec_from_pos(FVECT vec, int xpos, int ypos)
{
        double  uv[2];
        double  r2;
        
        SDsquare2disk(uv, (xpos+.5)/grid_res, (ypos+.5)/grid_res);
                                /* uniform hemispherical projection */
        r2 = uv[0]*uv[0] + uv[1]*uv[1];
        vec[0] = vec[1] = sqrt(2. - r2);
        vec[0] *= uv[0];
        vec[1] *= uv[1];
        vec[2] = output_orient*(1. - r2);
}

/* Compute grid position from normalized input/output vector */
void
pos_from_vec(int pos[2], const FVECT vec)
{
        double  sq[2];          /* uniform hemispherical projection */
        double  norm = 1./sqrt(1. + fabs(vec[2]));

        SDdisk2square(sq, vec[0]*norm, vec[1]*norm);

        pos[0] = (int)(sq[0]*grid_res);
        pos[1] = (int)(sq[1]*grid_res);
}

/* Compute volume associated with Gaussian lobe */
double
rbf_volume(const RBFVAL *rbfp)
{
        double  rad = R2ANG(rbfp->crad);
        FVECT   odir;
        double  elev, integ;
                                /* infinite integral approximation */
        integ = (2.*M_PI) * rbfp->peak * rad*rad;
                                /* check if we're near horizon */
        ovec_from_pos(odir, rbfp->gx, rbfp->gy);
        elev = output_orient*odir[2];
                                /* apply cut-off correction if > 1% */
        if (elev < 2.8*rad) {
                /* elev = asin(elev);   /* this is so crude, anyway... */
                integ *= 1. - .5*exp(-.5*elev*elev/(rad*rad));
        }
        return(integ);
}

/* Evaluate RBF for DSF at the given normalized outgoing direction */
double
eval_rbfrep(const RBFNODE *rp, const FVECT outvec)
{
        const double    rfact2 = (38./M_PI/M_PI)*(grid_res*grid_res);
        double          minval = bsdf_min*output_orient*outvec[2];
        int             pos[2];
        double          res = 0;
        const RBFVAL    *rbfp;
        FVECT           odir;
        double          rad2;
        int             n;
                                /* check for wrong side */
        if (outvec[2] > 0 ^ output_orient > 0)
                return(.0);
                                /* use minimum if no information avail. */
        if (rp == NULL)
                return(minval);
                                /* optimization for fast lobe culling */
        pos_from_vec(pos, outvec);
                                /* sum radial basis function */
        rbfp = rp->rbfa;
        for (n = rp->nrbf; n--; rbfp++) {
                int     d2 = (pos[0]-rbfp->gx)*(pos[0]-rbfp->gx) +
                                (pos[1]-rbfp->gy)*(pos[1]-rbfp->gy);
                rad2 = R2ANG(rbfp->crad);
                rad2 *= rad2;
                if (d2 > rad2*rfact2)
                        continue;
                ovec_from_pos(odir, rbfp->gx, rbfp->gy);
                res += rbfp->peak * exp((DOT(odir,outvec) - 1.) / rad2);
        }
        if (res < minval)       /* never return less than minval */
                return(minval);
        return(res);
}

/* Insert a new directional scattering function in our global list */
int
insert_dsf(RBFNODE *newrbf)
{
        RBFNODE         *rbf, *rbf_last;
        int             pos;
                                        /* check for redundant meas. */
        for (rbf = dsf_list; rbf != NULL; rbf = rbf->next)
                if (DOT(rbf->invec, newrbf->invec) >= 1.-FTINY) {
                        fprintf(stderr,
                                "%s: Duplicate incident measurement (ignored)\n",
                                        progname);
                        free(newrbf);
                        return(-1);
                }
                                        /* keep in ascending theta order */
        for (rbf_last = NULL, rbf = dsf_list; rbf != NULL;
                                        rbf_last = rbf, rbf = rbf->next)
                if (single_plane_incident && input_orient*rbf->invec[2] <
                                                input_orient*newrbf->invec[2])
                        break;
        if (rbf_last == NULL) {         /* insert new node in list */
                newrbf->ord = 0;
                newrbf->next = dsf_list;
                dsf_list = newrbf;
        } else {
                newrbf->ord = rbf_last->ord + 1;
                newrbf->next = rbf;
                rbf_last->next = newrbf;
        }
        rbf_last = newrbf;
        while (rbf != NULL) {           /* update ordinal positions */
                rbf->ord = rbf_last->ord + 1;
                rbf_last = rbf;
                rbf = rbf->next;
        }
        return(newrbf->ord);
}

/* Get the DSF indicated by its ordinal position */
RBFNODE *
get_dsf(int ord)
{
        RBFNODE         *rbf;

        for (rbf = dsf_list; rbf != NULL; rbf = rbf->next)
                if (rbf->ord == ord)
                        return(rbf);
        return(NULL);
}

/* Get triangle surface orientation (unnormalized) */
void
tri_orient(FVECT vres, const FVECT v1, const FVECT v2, const FVECT v3)
{
        FVECT   v2minus1, v3minus2;

        VSUB(v2minus1, v2, v1);
        VSUB(v3minus2, v3, v2);
        VCROSS(vres, v2minus1, v3minus2);
}

/* Determine if vertex order is reversed (inward normal) */
int
is_rev_tri(const FVECT v1, const FVECT v2, const FVECT v3)
{
        FVECT   tor;

        tri_orient(tor, v1, v2, v3);

        return(DOT(tor, v2) < 0.);
}

/* Find vertices completing triangles on either side of the given edge */
int
get_triangles(RBFNODE *rbfv[2], const MIGRATION *mig)
{
        const MIGRATION *ej1, *ej2;
        RBFNODE         *tv;

        rbfv[0] = rbfv[1] = NULL;
        if (mig == NULL)
                return(0);
        for (ej1 = mig->rbfv[0]->ejl; ej1 != NULL;
                                ej1 = nextedge(mig->rbfv[0],ej1)) {
                if (ej1 == mig)
                        continue;
                tv = opp_rbf(mig->rbfv[0],ej1);
                for (ej2 = tv->ejl; ej2 != NULL; ej2 = nextedge(tv,ej2))
                        if (opp_rbf(tv,ej2) == mig->rbfv[1]) {
                                rbfv[is_rev_tri(mig->rbfv[0]->invec,
                                                mig->rbfv[1]->invec,
                                                tv->invec)] = tv;
                                break;
                        }
        }
        return((rbfv[0] != NULL) + (rbfv[1] != NULL));
}

/* Clear our BSDF representation and free memory */
void
clear_bsdf_rep(void)
{
        while (mig_list != NULL) {
                MIGRATION       *mig = mig_list;
                mig_list = mig->next;
                free(mig);
        }
        while (dsf_list != NULL) {
                RBFNODE         *rbf = dsf_list;
                dsf_list = rbf->next;
                free(rbf);
        }
        bsdf_name[0] = '\0';
        bsdf_manuf[0] = '\0';
        inp_coverage = 0;
        single_plane_incident = -1;
        input_orient = output_orient = 0;
        grid_res = GRIDRES;
}

/* Write our BSDF mesh interpolant out to the given binary stream */
void
save_bsdf_rep(FILE *ofp)
{
        RBFNODE         *rbf;
        MIGRATION       *mig;
        int             i, n;
                                        /* finish header */
        if (bsdf_name[0])
                fprintf(ofp, "NAME=%s\n", bsdf_name);
        if (bsdf_manuf[0])
                fprintf(ofp, "MANUFACT=%s\n", bsdf_manuf);
        fprintf(ofp, "SYMMETRY=%d\n", !single_plane_incident * inp_coverage);
        fprintf(ofp, "IO_SIDES= %d %d\n", input_orient, output_orient);
        fprintf(ofp, "GRIDRES=%d\n", grid_res);
        fprintf(ofp, "BSDFMIN=%g\n", bsdf_min);
        fputformat(BSDFREP_FMT, ofp);
        fputc('\n', ofp);
                                        /* write each DSF */
        for (rbf = dsf_list; rbf != NULL; rbf = rbf->next) {
                putint(rbf->ord, 4, ofp);
                putflt(rbf->invec[0], ofp);
                putflt(rbf->invec[1], ofp);
                putflt(rbf->invec[2], ofp);
                putflt(rbf->vtotal, ofp);
                putint(rbf->nrbf, 4, ofp);
                for (i = 0; i < rbf->nrbf; i++) {
                        putflt(rbf->rbfa[i].peak, ofp);
                        putint(rbf->rbfa[i].crad, 2, ofp);
                        putint(rbf->rbfa[i].gx, 1, ofp);
                        putint(rbf->rbfa[i].gy, 1, ofp);
                }
        }
        putint(-1, 4, ofp);             /* terminator */
                                        /* write each migration matrix */
        for (mig = mig_list; mig != NULL; mig = mig->next) {
                int     zerocnt = 0;
                putint(mig->rbfv[0]->ord, 4, ofp);
                putint(mig->rbfv[1]->ord, 4, ofp);
                                        /* write out as sparse data */
                n = mtx_nrows(mig) * mtx_ncols(mig);
                for (i = 0; i < n; i++) {
                        if (zerocnt == 0xff) {
                                putint(0xff, 1, ofp); zerocnt = 0;
                        }
                        if (mig->mtx[i] != 0) {
                                putint(zerocnt, 1, ofp); zerocnt = 0;
                                putflt(mig->mtx[i], ofp);
                        } else
                                ++zerocnt;
                }
                putint(zerocnt, 1, ofp);
        }
        putint(-1, 4, ofp);             /* terminator */
        putint(-1, 4, ofp);
        if (fflush(ofp) == EOF) {
                fprintf(stderr, "%s: error writing BSDF interpolant\n",
                                progname);
                exit(1);
        }
}

/* Check header line for critical information */
static int
headline(char *s, void *p)
{
        char    fmt[32];

        if (!strncmp(s, "NAME=", 5)) {
                strcpy(bsdf_name, s+5);
                bsdf_name[strlen(bsdf_name)-1] = '\0';
        }
        if (!strncmp(s, "MANUFACT=", 9)) {
                strcpy(bsdf_manuf, s+9);
                bsdf_manuf[strlen(bsdf_manuf)-1] = '\0';
        }
        if (!strncmp(s, "SYMMETRY=", 9)) {
                inp_coverage = atoi(s+9);
                single_plane_incident = !inp_coverage;
                return(0);
        }
        if (!strncmp(s, "IO_SIDES=", 9)) {
                sscanf(s+9, "%d %d", &input_orient, &output_orient);
                return(0);
        }
        if (!strncmp(s, "GRIDRES=", 8)) {
                sscanf(s+8, "%d", &grid_res);
                return(0);
        }
        if (!strncmp(s, "BSDFMIN=", 8)) {
                sscanf(s+8, "%lf", &bsdf_min);
                return(0);
        }
        if (formatval(fmt, s) && strcmp(fmt, BSDFREP_FMT))
                return(-1);
        return(0);
}

/* Read a BSDF mesh interpolant from the given binary stream */
int
load_bsdf_rep(FILE *ifp)
{
        RBFNODE         rbfh;
        int             from_ord, to_ord;
        int             i;

        clear_bsdf_rep();
        if (ifp == NULL)
                return(0);
        if (getheader(ifp, headline, NULL) < 0 || single_plane_incident < 0 |
                        !input_orient | !output_orient) {
                fprintf(stderr, "%s: missing/bad format for BSDF interpolant\n",
                                progname);
                return(0);
        }
        memset(&rbfh, 0, sizeof(rbfh)); /* read each DSF */
        while ((rbfh.ord = getint(4, ifp)) >= 0) {
                RBFNODE         *newrbf;

                rbfh.invec[0] = getflt(ifp);
                rbfh.invec[1] = getflt(ifp);
                rbfh.invec[2] = getflt(ifp);
                if (normalize(rbfh.invec) == 0) {
                        fprintf(stderr, "%s: zero incident vector\n", progname);
                        return(0);
                }
                rbfh.vtotal = getflt(ifp);
                rbfh.nrbf = getint(4, ifp);
                newrbf = (RBFNODE *)malloc(sizeof(RBFNODE) +
                                        sizeof(RBFVAL)*(rbfh.nrbf-1));
                if (newrbf == NULL)
                        goto memerr;
                *newrbf = rbfh;
                for (i = 0; i < rbfh.nrbf; i++) {
                        newrbf->rbfa[i].peak = getflt(ifp);
                        newrbf->rbfa[i].crad = getint(2, ifp) & 0xffff;
                        newrbf->rbfa[i].gx = getint(1, ifp) & 0xff;
                        newrbf->rbfa[i].gy = getint(1, ifp) & 0xff;
                }
                if (feof(ifp))
                        goto badEOF;
                                        /* insert in global list */
                if (insert_dsf(newrbf) != rbfh.ord) {
                        fprintf(stderr, "%s: error adding DSF\n", progname);
                        return(0);
                }
        }
                                        /* read each migration matrix */
        while ((from_ord = getint(4, ifp)) >= 0 &&
                        (to_ord = getint(4, ifp)) >= 0) {
                RBFNODE         *from_rbf = get_dsf(from_ord);
                RBFNODE         *to_rbf = get_dsf(to_ord);
                MIGRATION       *newmig;
                int             n;

                if ((from_rbf == NULL) | (to_rbf == NULL)) {
                        fprintf(stderr,
                                "%s: bad DSF reference in migration edge\n",
                                        progname);
                        return(0);
                }
                n = from_rbf->nrbf * to_rbf->nrbf;
                newmig = (MIGRATION *)malloc(sizeof(MIGRATION) +
                                                sizeof(float)*(n-1));
                if (newmig == NULL)
                        goto memerr;
                newmig->rbfv[0] = from_rbf;
                newmig->rbfv[1] = to_rbf;
                memset(newmig->mtx, 0, sizeof(float)*n);
                for (i = 0; ; ) {       /* read sparse data */
                        int     zc = getint(1, ifp) & 0xff;
                        if ((i += zc) >= n)
                                break;
                        if (zc == 0xff)
                                continue;
                        newmig->mtx[i++] = getflt(ifp);
                }
                if (feof(ifp))
                        goto badEOF;
                                        /* insert in edge lists */
                newmig->enxt[0] = from_rbf->ejl;
                from_rbf->ejl = newmig;
                newmig->enxt[1] = to_rbf->ejl;
                to_rbf->ejl = newmig;
                                        /* push onto global list */
                newmig->next = mig_list;
                mig_list = newmig;
        }
        return(1);                      /* success! */
memerr:
        fprintf(stderr, "%s: Out of memory in load_bsdf_rep()\n", progname);
        exit(1);
badEOF:
        fprintf(stderr, "%s: Unexpected EOF in load_bsdf_rep()\n", progname);
        return(0);
}
Revision:	2.19
Committed:	Sat Nov 9 05:47:49 2013 UTC (10 years, 5 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.18:	+18 -1 lines
Log Message:	Added tracking of BSDF sample name
#	User	Rev	Content
1	greg	2.1	#ifndef lint
2	greg	2.19	static const char RCSid[] = "$Id: bsdfrep.c,v 2.18 2013/11/08 05:37:20 greg Exp $";
3	greg	2.1	#endif
4			/*
5			* Support BSDF representation as radial basis functions.
6			*
7			* G. Ward
8			*/
9
10			#define _USE_MATH_DEFINES
11			#include <stdlib.h>
12	greg	2.2	#include <string.h>
13	greg	2.1	#include <math.h>
14			#include "rtio.h"
15			#include "resolu.h"
16			#include "bsdfrep.h"
17	greg	2.19	/* name and manufacturer if known */
18			char bsdf_name[256];
19			char bsdf_manuf[256];
20	greg	2.5	/* active grid resolution */
21			int grid_res = GRIDRES;
22
23	greg	2.4	/* coverage/symmetry using INP_QUAD? flags */
24	greg	2.1	int inp_coverage = 0;
25			/* all incident angles in-plane so far? */
26			int single_plane_incident = -1;
27
28			/* input/output orientations */
29			int input_orient = 0;
30			int output_orient = 0;
31
32	greg	2.12	/* BSDF histogram */
33	greg	2.15	unsigned long bsdf_hist[HISTLEN];
34	greg	2.12
35			/* BSDF value for boundary regions */
36			double bsdf_min = 0;
37
38	greg	2.1	/* processed incident DSF measurements */
39			RBFNODE *dsf_list = NULL;
40
41			/* RBF-linking matrices (edges) */
42			MIGRATION *mig_list = NULL;
43
44			/* current input direction */
45			double theta_in_deg, phi_in_deg;
46
47			/* Register new input direction */
48			int
49			new_input_direction(double new_theta, double new_phi)
50			{
51			if (!input_orient) /* check input orientation */
52			input_orient = 1 - 2*(new_theta > 90.);
53			else if (input_orient > 0 ^ new_theta < 90.) {
54			fprintf(stderr,
55			"%s: Cannot handle input angles on both sides of surface\n",
56			progname);
57			return(0);
58			}
59			/* normalize angle ranges */
60			while (new_theta < -180.)
61			new_theta += 360.;
62			while (new_theta > 180.)
63			new_theta -= 360.;
64			if (new_theta < 0) {
65			new_theta = -new_theta;
66			new_phi += 180.;
67			}
68	greg	2.6	if ((theta_in_deg = new_theta) < 1.0)
69			return(1); /* don't rely on phi near normal */
70	greg	2.1	while (new_phi < 0)
71			new_phi += 360.;
72			while (new_phi >= 360.)
73			new_phi -= 360.;
74			if (single_plane_incident > 0) /* check input coverage */
75			single_plane_incident = (round(new_phi) == round(phi_in_deg));
76			else if (single_plane_incident < 0)
77			single_plane_incident = 1;
78			phi_in_deg = new_phi;
79			if ((1. < new_phi) & (new_phi < 89.))
80			inp_coverage \|= INP_QUAD1;
81			else if ((91. < new_phi) & (new_phi < 179.))
82			inp_coverage \|= INP_QUAD2;
83			else if ((181. < new_phi) & (new_phi < 269.))
84			inp_coverage \|= INP_QUAD3;
85			else if ((271. < new_phi) & (new_phi < 359.))
86			inp_coverage \|= INP_QUAD4;
87			return(1);
88			}
89
90			/* Apply symmetry to the given vector based on distribution */
91			int
92			use_symmetry(FVECT vec)
93			{
94	greg	2.11	const double phi = get_phi360(vec);
95	greg	2.1
96			switch (inp_coverage) {
97			case INP_QUAD1\|INP_QUAD2\|INP_QUAD3\|INP_QUAD4:
98			break;
99			case INP_QUAD1\|INP_QUAD2:
100			if ((-FTINY > phi) \| (phi > 180.+FTINY))
101			goto mir_y;
102			break;
103			case INP_QUAD2\|INP_QUAD3:
104			if ((90.-FTINY > phi) \| (phi > 270.+FTINY))
105			goto mir_x;
106			break;
107			case INP_QUAD3\|INP_QUAD4:
108			if ((180.-FTINY > phi) \| (phi > 360.+FTINY))
109			goto mir_y;
110			break;
111			case INP_QUAD4\|INP_QUAD1:
112			if ((270.-FTINY > phi) & (phi > 90.+FTINY))
113			goto mir_x;
114			break;
115			case INP_QUAD1:
116			if ((-FTINY > phi) \| (phi > 90.+FTINY))
117			switch ((int)(phi*(1./90.))) {
118			case 1: goto mir_x;
119			case 2: goto mir_xy;
120			case 3: goto mir_y;
121			}
122			break;
123			case INP_QUAD2:
124			if ((90.-FTINY > phi) \| (phi > 180.+FTINY))
125			switch ((int)(phi*(1./90.))) {
126			case 0: goto mir_x;
127			case 2: goto mir_y;
128			case 3: goto mir_xy;
129			}
130			break;
131			case INP_QUAD3:
132			if ((180.-FTINY > phi) \| (phi > 270.+FTINY))
133			switch ((int)(phi*(1./90.))) {
134			case 0: goto mir_xy;
135			case 1: goto mir_y;
136			case 3: goto mir_x;
137			}
138			break;
139			case INP_QUAD4:
140			if ((270.-FTINY > phi) \| (phi > 360.+FTINY))
141			switch ((int)(phi*(1./90.))) {
142			case 0: goto mir_y;
143			case 1: goto mir_xy;
144			case 2: goto mir_x;
145			}
146			break;
147			default:
148			fprintf(stderr, "%s: Illegal input coverage (%d)\n",
149			progname, inp_coverage);
150			exit(1);
151			}
152			return(0); /* in range */
153			mir_x:
154			vec[0] = -vec[0];
155			return(MIRROR_X);
156			mir_y:
157			vec[1] = -vec[1];
158			return(MIRROR_Y);
159			mir_xy:
160			vec[0] = -vec[0];
161			vec[1] = -vec[1];
162			return(MIRROR_X\|MIRROR_Y);
163			}
164
165			/* Reverse symmetry based on what was done before */
166			void
167			rev_symmetry(FVECT vec, int sym)
168			{
169			if (sym & MIRROR_X)
170			vec[0] = -vec[0];
171			if (sym & MIRROR_Y)
172			vec[1] = -vec[1];
173			}
174
175			/* Reverse symmetry for an RBF distribution */
176			void
177			rev_rbf_symmetry(RBFNODE *rbf, int sym)
178			{
179			int n;
180
181			rev_symmetry(rbf->invec, sym);
182			if (sym & MIRROR_X)
183			for (n = rbf->nrbf; n-- > 0; )
184	greg	2.5	rbf->rbfa[n].gx = grid_res-1 - rbf->rbfa[n].gx;
185	greg	2.1	if (sym & MIRROR_Y)
186			for (n = rbf->nrbf; n-- > 0; )
187	greg	2.5	rbf->rbfa[n].gy = grid_res-1 - rbf->rbfa[n].gy;
188	greg	2.1	}
189
190	greg	2.6	/* Rotate RBF to correspond to given incident vector */
191			void
192			rotate_rbf(RBFNODE *rbf, const FVECT invec)
193			{
194			static const FVECT vnorm = {.0, .0, 1.};
195			const double phi = atan2(invec[1],invec[0]) -
196			atan2(rbf->invec[1],rbf->invec[0]);
197			FVECT outvec;
198			int pos[2];
199			int n;
200	greg	2.8
201	greg	2.10	for (n = ((-.01 > phi) \| (phi > .01))*rbf->nrbf; n-- > 0; ) {
202	greg	2.6	ovec_from_pos(outvec, rbf->rbfa[n].gx, rbf->rbfa[n].gy);
203			spinvector(outvec, outvec, vnorm, phi);
204			pos_from_vec(pos, outvec);
205			rbf->rbfa[n].gx = pos[0];
206			rbf->rbfa[n].gy = pos[1];
207			}
208			VCOPY(rbf->invec, invec);
209			}
210
211	greg	2.1	/* Compute outgoing vector from grid position */
212			void
213			ovec_from_pos(FVECT vec, int xpos, int ypos)
214			{
215			double uv[2];
216			double r2;
217
218	greg	2.8	SDsquare2disk(uv, (xpos+.5)/grid_res, (ypos+.5)/grid_res);
219	greg	2.1	/* uniform hemispherical projection */
220			r2 = uv[0]uv[0] + uv[1]uv[1];
221			vec[0] = vec[1] = sqrt(2. - r2);
222			vec[0] *= uv[0];
223			vec[1] *= uv[1];
224			vec[2] = output_orient*(1. - r2);
225			}
226
227			/* Compute grid position from normalized input/output vector */
228			void
229			pos_from_vec(int pos[2], const FVECT vec)
230			{
231			double sq[2]; /* uniform hemispherical projection */
232			double norm = 1./sqrt(1. + fabs(vec[2]));
233
234			SDdisk2square(sq, vec[0]norm, vec[1]norm);
235
236	greg	2.5	pos[0] = (int)(sq[0]*grid_res);
237			pos[1] = (int)(sq[1]*grid_res);
238	greg	2.1	}
239
240	greg	2.14	/* Compute volume associated with Gaussian lobe */
241			double
242			rbf_volume(const RBFVAL *rbfp)
243			{
244			double rad = R2ANG(rbfp->crad);
245			FVECT odir;
246			double elev, integ;
247			/* infinite integral approximation */
248			integ = (2.M_PI) rbfp->peak * rad*rad;
249			/* check if we're near horizon */
250			ovec_from_pos(odir, rbfp->gx, rbfp->gy);
251			elev = output_orient*odir[2];
252			/* apply cut-off correction if > 1% */
253			if (elev < 2.8*rad) {
254			/* elev = asin(elev); /* this is so crude, anyway... */
255			integ = 1. - .5exp(-.5elevelev/(rad*rad));
256			}
257			return(integ);
258			}
259
260	greg	2.1	/* Evaluate RBF for DSF at the given normalized outgoing direction */
261			double
262			eval_rbfrep(const RBFNODE *rp, const FVECT outvec)
263			{
264	greg	2.17	const double rfact2 = (38./M_PI/M_PI)(grid_resgrid_res);
265	greg	2.13	double minval = bsdf_minoutput_orientoutvec[2];
266	greg	2.16	int pos[2];
267	greg	2.8	double res = 0;
268	greg	2.1	const RBFVAL *rbfp;
269			FVECT odir;
270	greg	2.16	double rad2;
271	greg	2.1	int n;
272	greg	2.14	/* check for wrong side */
273			if (outvec[2] > 0 ^ output_orient > 0)
274			return(.0);
275	greg	2.12	/* use minimum if no information avail. */
276	greg	2.14	if (rp == NULL)
277	greg	2.13	return(minval);
278	greg	2.16	/* optimization for fast lobe culling */
279			pos_from_vec(pos, outvec);
280	greg	2.14	/* sum radial basis function */
281	greg	2.1	rbfp = rp->rbfa;
282			for (n = rp->nrbf; n--; rbfp++) {
283	greg	2.16	int d2 = (pos[0]-rbfp->gx)*(pos[0]-rbfp->gx) +
284			(pos[1]-rbfp->gy)*(pos[1]-rbfp->gy);
285			rad2 = R2ANG(rbfp->crad);
286			rad2 *= rad2;
287	greg	2.17	if (d2 > rad2*rfact2)
288	greg	2.16	continue;
289	greg	2.1	ovec_from_pos(odir, rbfp->gx, rbfp->gy);
290	greg	2.16	res += rbfp->peak * exp((DOT(odir,outvec) - 1.) / rad2);
291	greg	2.1	}
292	greg	2.13	if (res < minval) /* never return less than minval */
293			return(minval);
294	greg	2.1	return(res);
295			}
296
297			/* Insert a new directional scattering function in our global list */
298			int
299			insert_dsf(RBFNODE *newrbf)
300			{
301			RBFNODE rbf, rbf_last;
302			int pos;
303			/* check for redundant meas. */
304			for (rbf = dsf_list; rbf != NULL; rbf = rbf->next)
305			if (DOT(rbf->invec, newrbf->invec) >= 1.-FTINY) {
306			fprintf(stderr,
307			"%s: Duplicate incident measurement (ignored)\n",
308			progname);
309			free(newrbf);
310			return(-1);
311			}
312			/* keep in ascending theta order */
313			for (rbf_last = NULL, rbf = dsf_list; rbf != NULL;
314			rbf_last = rbf, rbf = rbf->next)
315			if (single_plane_incident && input_orient*rbf->invec[2] <
316			input_orient*newrbf->invec[2])
317			break;
318			if (rbf_last == NULL) { /* insert new node in list */
319			newrbf->ord = 0;
320			newrbf->next = dsf_list;
321			dsf_list = newrbf;
322			} else {
323			newrbf->ord = rbf_last->ord + 1;
324			newrbf->next = rbf;
325			rbf_last->next = newrbf;
326			}
327			rbf_last = newrbf;
328			while (rbf != NULL) { /* update ordinal positions */
329			rbf->ord = rbf_last->ord + 1;
330			rbf_last = rbf;
331			rbf = rbf->next;
332			}
333			return(newrbf->ord);
334			}
335
336			/* Get the DSF indicated by its ordinal position */
337			RBFNODE *
338			get_dsf(int ord)
339			{
340			RBFNODE *rbf;
341
342			for (rbf = dsf_list; rbf != NULL; rbf = rbf->next)
343	greg	2.3	if (rbf->ord == ord)
344	greg	2.1	return(rbf);
345			return(NULL);
346			}
347
348			/* Get triangle surface orientation (unnormalized) */
349			void
350			tri_orient(FVECT vres, const FVECT v1, const FVECT v2, const FVECT v3)
351			{
352			FVECT v2minus1, v3minus2;
353
354			VSUB(v2minus1, v2, v1);
355			VSUB(v3minus2, v3, v2);
356			VCROSS(vres, v2minus1, v3minus2);
357			}
358
359			/* Determine if vertex order is reversed (inward normal) */
360			int
361			is_rev_tri(const FVECT v1, const FVECT v2, const FVECT v3)
362			{
363			FVECT tor;
364
365			tri_orient(tor, v1, v2, v3);
366
367			return(DOT(tor, v2) < 0.);
368			}
369
370			/* Find vertices completing triangles on either side of the given edge */
371			int
372			get_triangles(RBFNODE rbfv[2], const MIGRATION mig)
373			{
374	greg	2.4	const MIGRATION ej1, ej2;
375	greg	2.1	RBFNODE *tv;
376
377			rbfv[0] = rbfv[1] = NULL;
378			if (mig == NULL)
379			return(0);
380	greg	2.4	for (ej1 = mig->rbfv[0]->ejl; ej1 != NULL;
381			ej1 = nextedge(mig->rbfv[0],ej1)) {
382			if (ej1 == mig)
383	greg	2.1	continue;
384	greg	2.4	tv = opp_rbf(mig->rbfv[0],ej1);
385	greg	2.1	for (ej2 = tv->ejl; ej2 != NULL; ej2 = nextedge(tv,ej2))
386			if (opp_rbf(tv,ej2) == mig->rbfv[1]) {
387			rbfv[is_rev_tri(mig->rbfv[0]->invec,
388			mig->rbfv[1]->invec,
389			tv->invec)] = tv;
390			break;
391			}
392			}
393			return((rbfv[0] != NULL) + (rbfv[1] != NULL));
394			}
395
396	greg	2.4	/* Clear our BSDF representation and free memory */
397			void
398			clear_bsdf_rep(void)
399			{
400			while (mig_list != NULL) {
401			MIGRATION *mig = mig_list;
402			mig_list = mig->next;
403			free(mig);
404			}
405			while (dsf_list != NULL) {
406			RBFNODE *rbf = dsf_list;
407			dsf_list = rbf->next;
408			free(rbf);
409			}
410	greg	2.19	bsdf_name[0] = '\0';
411			bsdf_manuf[0] = '\0';
412	greg	2.4	inp_coverage = 0;
413			single_plane_incident = -1;
414			input_orient = output_orient = 0;
415	greg	2.5	grid_res = GRIDRES;
416	greg	2.4	}
417
418	greg	2.1	/* Write our BSDF mesh interpolant out to the given binary stream */
419			void
420			save_bsdf_rep(FILE *ofp)
421			{
422			RBFNODE *rbf;
423			MIGRATION *mig;
424			int i, n;
425			/* finish header */
426	greg	2.19	if (bsdf_name[0])
427			fprintf(ofp, "NAME=%s\n", bsdf_name);
428			if (bsdf_manuf[0])
429			fprintf(ofp, "MANUFACT=%s\n", bsdf_manuf);
430	greg	2.2	fprintf(ofp, "SYMMETRY=%d\n", !single_plane_incident * inp_coverage);
431			fprintf(ofp, "IO_SIDES= %d %d\n", input_orient, output_orient);
432	greg	2.5	fprintf(ofp, "GRIDRES=%d\n", grid_res);
433	greg	2.12	fprintf(ofp, "BSDFMIN=%g\n", bsdf_min);
434	greg	2.1	fputformat(BSDFREP_FMT, ofp);
435			fputc('\n', ofp);
436			/* write each DSF */
437			for (rbf = dsf_list; rbf != NULL; rbf = rbf->next) {
438			putint(rbf->ord, 4, ofp);
439			putflt(rbf->invec[0], ofp);
440			putflt(rbf->invec[1], ofp);
441			putflt(rbf->invec[2], ofp);
442			putflt(rbf->vtotal, ofp);
443			putint(rbf->nrbf, 4, ofp);
444			for (i = 0; i < rbf->nrbf; i++) {
445			putflt(rbf->rbfa[i].peak, ofp);
446			putint(rbf->rbfa[i].crad, 2, ofp);
447			putint(rbf->rbfa[i].gx, 1, ofp);
448			putint(rbf->rbfa[i].gy, 1, ofp);
449			}
450			}
451			putint(-1, 4, ofp); /* terminator */
452			/* write each migration matrix */
453	greg	2.2	for (mig = mig_list; mig != NULL; mig = mig->next) {
454			int zerocnt = 0;
455	greg	2.1	putint(mig->rbfv[0]->ord, 4, ofp);
456			putint(mig->rbfv[1]->ord, 4, ofp);
457	greg	2.2	/* write out as sparse data */
458	greg	2.1	n = mtx_nrows(mig) * mtx_ncols(mig);
459	greg	2.2	for (i = 0; i < n; i++) {
460	greg	2.3	if (zerocnt == 0xff) {
461			putint(0xff, 1, ofp); zerocnt = 0;
462	greg	2.2	}
463			if (mig->mtx[i] != 0) {
464			putint(zerocnt, 1, ofp); zerocnt = 0;
465			putflt(mig->mtx[i], ofp);
466			} else
467			++zerocnt;
468			}
469			putint(zerocnt, 1, ofp);
470	greg	2.1	}
471			putint(-1, 4, ofp); /* terminator */
472			putint(-1, 4, ofp);
473			if (fflush(ofp) == EOF) {
474			fprintf(stderr, "%s: error writing BSDF interpolant\n",
475			progname);
476			exit(1);
477			}
478			}
479
480	greg	2.2	/* Check header line for critical information */
481			static int
482			headline(char s, void p)
483			{
484			char fmt[32];
485
486	greg	2.19	if (!strncmp(s, "NAME=", 5)) {
487			strcpy(bsdf_name, s+5);
488			bsdf_name[strlen(bsdf_name)-1] = '\0';
489			}
490			if (!strncmp(s, "MANUFACT=", 9)) {
491			strcpy(bsdf_manuf, s+9);
492			bsdf_manuf[strlen(bsdf_manuf)-1] = '\0';
493			}
494	greg	2.2	if (!strncmp(s, "SYMMETRY=", 9)) {
495			inp_coverage = atoi(s+9);
496			single_plane_incident = !inp_coverage;
497			return(0);
498			}
499			if (!strncmp(s, "IO_SIDES=", 9)) {
500			sscanf(s+9, "%d %d", &input_orient, &output_orient);
501			return(0);
502			}
503	greg	2.5	if (!strncmp(s, "GRIDRES=", 8)) {
504			sscanf(s+8, "%d", &grid_res);
505			return(0);
506			}
507	greg	2.12	if (!strncmp(s, "BSDFMIN=", 8)) {
508			sscanf(s+8, "%lf", &bsdf_min);
509			return(0);
510			}
511	greg	2.2	if (formatval(fmt, s) && strcmp(fmt, BSDFREP_FMT))
512			return(-1);
513			return(0);
514			}
515
516	greg	2.1	/* Read a BSDF mesh interpolant from the given binary stream */
517			int
518			load_bsdf_rep(FILE *ifp)
519			{
520			RBFNODE rbfh;
521			int from_ord, to_ord;
522			int i;
523	greg	2.4
524			clear_bsdf_rep();
525	greg	2.5	if (ifp == NULL)
526			return(0);
527	greg	2.2	if (getheader(ifp, headline, NULL) < 0 \|\| single_plane_incident < 0 \|
528			!input_orient \| !output_orient) {
529	greg	2.1	fprintf(stderr, "%s: missing/bad format for BSDF interpolant\n",
530			progname);
531			return(0);
532			}
533	greg	2.18	memset(&rbfh, 0, sizeof(rbfh)); /* read each DSF */
534	greg	2.1	while ((rbfh.ord = getint(4, ifp)) >= 0) {
535			RBFNODE *newrbf;
536
537			rbfh.invec[0] = getflt(ifp);
538			rbfh.invec[1] = getflt(ifp);
539			rbfh.invec[2] = getflt(ifp);
540	greg	2.9	if (normalize(rbfh.invec) == 0) {
541			fprintf(stderr, "%s: zero incident vector\n", progname);
542			return(0);
543			}
544	greg	2.3	rbfh.vtotal = getflt(ifp);
545	greg	2.1	rbfh.nrbf = getint(4, ifp);
546			newrbf = (RBFNODE *)malloc(sizeof(RBFNODE) +
547			sizeof(RBFVAL)*(rbfh.nrbf-1));
548			if (newrbf == NULL)
549			goto memerr;
550	greg	2.18	*newrbf = rbfh;
551	greg	2.1	for (i = 0; i < rbfh.nrbf; i++) {
552			newrbf->rbfa[i].peak = getflt(ifp);
553			newrbf->rbfa[i].crad = getint(2, ifp) & 0xffff;
554			newrbf->rbfa[i].gx = getint(1, ifp) & 0xff;
555			newrbf->rbfa[i].gy = getint(1, ifp) & 0xff;
556			}
557			if (feof(ifp))
558			goto badEOF;
559			/* insert in global list */
560			if (insert_dsf(newrbf) != rbfh.ord) {
561			fprintf(stderr, "%s: error adding DSF\n", progname);
562			return(0);
563			}
564			}
565			/* read each migration matrix */
566			while ((from_ord = getint(4, ifp)) >= 0 &&
567			(to_ord = getint(4, ifp)) >= 0) {
568			RBFNODE *from_rbf = get_dsf(from_ord);
569			RBFNODE *to_rbf = get_dsf(to_ord);
570			MIGRATION *newmig;
571			int n;
572
573			if ((from_rbf == NULL) \| (to_rbf == NULL)) {
574			fprintf(stderr,
575			"%s: bad DSF reference in migration edge\n",
576			progname);
577			return(0);
578			}
579			n = from_rbf->nrbf * to_rbf->nrbf;
580			newmig = (MIGRATION *)malloc(sizeof(MIGRATION) +
581			sizeof(float)*(n-1));
582			if (newmig == NULL)
583			goto memerr;
584			newmig->rbfv[0] = from_rbf;
585			newmig->rbfv[1] = to_rbf;
586	greg	2.2	memset(newmig->mtx, 0, sizeof(float)*n);
587			for (i = 0; ; ) { /* read sparse data */
588			int zc = getint(1, ifp) & 0xff;
589			if ((i += zc) >= n)
590			break;
591	greg	2.3	if (zc == 0xff)
592			continue;
593	greg	2.2	newmig->mtx[i++] = getflt(ifp);
594			}
595	greg	2.1	if (feof(ifp))
596			goto badEOF;
597			/* insert in edge lists */
598			newmig->enxt[0] = from_rbf->ejl;
599			from_rbf->ejl = newmig;
600			newmig->enxt[1] = to_rbf->ejl;
601			to_rbf->ejl = newmig;
602			/* push onto global list */
603			newmig->next = mig_list;
604			mig_list = newmig;
605			}
606			return(1); /* success! */
607			memerr:
608			fprintf(stderr, "%s: Out of memory in load_bsdf_rep()\n", progname);
609			exit(1);
610			badEOF:
611			fprintf(stderr, "%s: Unexpected EOF in load_bsdf_rep()\n", progname);
612			return(0);
613			}