src/cv/bsdfrep.c

#ifndef lint
static const char RCSid[] = "$Id: bsdfrep.c,v 2.5 2012/11/07 03:04:23 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"
                                /* 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;

                                /* 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)
{
        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;
#ifdef DEBUG
        {
                double  tdiff = 180./M_PI*fabs(acos(invec[2])-acos(rbf->invec[2]));
                if (tdiff >= 1.5)
                        fprintf(stderr,
                        "%s: Warning - rotated theta differs by %.1f degrees\n",
                                        progname, tdiff);
        }
#endif
        for (n = 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 volume associated with Gaussian lobe */
double
rbf_volume(const RBFVAL *rbfp)
{
        double  rad = R2ANG(rbfp->crad);

        return((2.*M_PI) * rbfp->peak * rad*rad);
}

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

/* Evaluate RBF for DSF at the given normalized outgoing direction */
double
eval_rbfrep(const RBFNODE *rp, const FVECT outvec)
{
        double          res = .0;
        const RBFVAL    *rbfp;
        FVECT           odir;
        double          sig2;
        int             n;

        if (rp == NULL)
                return(.0);
        rbfp = rp->rbfa;
        for (n = rp->nrbf; n--; rbfp++) {
                ovec_from_pos(odir, rbfp->gx, rbfp->gy);
                sig2 = R2ANG(rbfp->crad);
                sig2 = (DOT(odir,outvec) - 1.) / (sig2*sig2);
                if (sig2 > -19.)
                        res += rbfp->peak * exp(sig2);
        }
        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);
        }
        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 */
        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);
        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, "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 (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);
        }
        rbfh.next = NULL;               /* read each DSF */
        rbfh.ejl = NULL;
        while ((rbfh.ord = getint(4, ifp)) >= 0) {
                RBFNODE         *newrbf;

                rbfh.invec[0] = getflt(ifp);
                rbfh.invec[1] = getflt(ifp);
                rbfh.invec[2] = getflt(ifp);
                rbfh.vtotal = getflt(ifp);
                rbfh.nrbf = getint(4, ifp);
                newrbf = (RBFNODE *)malloc(sizeof(RBFNODE) +
                                        sizeof(RBFVAL)*(rbfh.nrbf-1));
                if (newrbf == NULL)
                        goto memerr;
                memcpy(newrbf, &rbfh, sizeof(RBFNODE));
                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:	2.6
Committed:	Thu Nov 8 00:31:17 2012 UTC (11 years, 5 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.5:	+32 -2 lines
Log Message:	Isotropic BRDF interpolation seems to work now
#	User	Rev	Content
1	greg	2.1	#ifndef lint
2	greg	2.6	static const char RCSid[] = "$Id: bsdfrep.c,v 2.5 2012/11/07 03:04:23 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	2.5	/* active grid resolution */
18			int grid_res = GRIDRES;
19
20	greg	2.4	/* coverage/symmetry using INP_QUAD? flags */
21	greg	2.1	int inp_coverage = 0;
22			/* all incident angles in-plane so far? */
23			int single_plane_incident = -1;
24
25			/* input/output orientations */
26			int input_orient = 0;
27			int output_orient = 0;
28
29			/* processed incident DSF measurements */
30			RBFNODE *dsf_list = NULL;
31
32			/* RBF-linking matrices (edges) */
33			MIGRATION *mig_list = NULL;
34
35			/* current input direction */
36			double theta_in_deg, phi_in_deg;
37
38			/* Register new input direction */
39			int
40			new_input_direction(double new_theta, double new_phi)
41			{
42			if (!input_orient) /* check input orientation */
43			input_orient = 1 - 2*(new_theta > 90.);
44			else if (input_orient > 0 ^ new_theta < 90.) {
45			fprintf(stderr,
46			"%s: Cannot handle input angles on both sides of surface\n",
47			progname);
48			return(0);
49			}
50			/* normalize angle ranges */
51			while (new_theta < -180.)
52			new_theta += 360.;
53			while (new_theta > 180.)
54			new_theta -= 360.;
55			if (new_theta < 0) {
56			new_theta = -new_theta;
57			new_phi += 180.;
58			}
59	greg	2.6	if ((theta_in_deg = new_theta) < 1.0)
60			return(1); /* don't rely on phi near normal */
61	greg	2.1	while (new_phi < 0)
62			new_phi += 360.;
63			while (new_phi >= 360.)
64			new_phi -= 360.;
65			if (single_plane_incident > 0) /* check input coverage */
66			single_plane_incident = (round(new_phi) == round(phi_in_deg));
67			else if (single_plane_incident < 0)
68			single_plane_incident = 1;
69			phi_in_deg = new_phi;
70			if ((1. < new_phi) & (new_phi < 89.))
71			inp_coverage \|= INP_QUAD1;
72			else if ((91. < new_phi) & (new_phi < 179.))
73			inp_coverage \|= INP_QUAD2;
74			else if ((181. < new_phi) & (new_phi < 269.))
75			inp_coverage \|= INP_QUAD3;
76			else if ((271. < new_phi) & (new_phi < 359.))
77			inp_coverage \|= INP_QUAD4;
78			return(1);
79			}
80
81			/* Apply symmetry to the given vector based on distribution */
82			int
83			use_symmetry(FVECT vec)
84			{
85			double phi = get_phi360(vec);
86
87			switch (inp_coverage) {
88			case INP_QUAD1\|INP_QUAD2\|INP_QUAD3\|INP_QUAD4:
89			break;
90			case INP_QUAD1\|INP_QUAD2:
91			if ((-FTINY > phi) \| (phi > 180.+FTINY))
92			goto mir_y;
93			break;
94			case INP_QUAD2\|INP_QUAD3:
95			if ((90.-FTINY > phi) \| (phi > 270.+FTINY))
96			goto mir_x;
97			break;
98			case INP_QUAD3\|INP_QUAD4:
99			if ((180.-FTINY > phi) \| (phi > 360.+FTINY))
100			goto mir_y;
101			break;
102			case INP_QUAD4\|INP_QUAD1:
103			if ((270.-FTINY > phi) & (phi > 90.+FTINY))
104			goto mir_x;
105			break;
106			case INP_QUAD1:
107			if ((-FTINY > phi) \| (phi > 90.+FTINY))
108			switch ((int)(phi*(1./90.))) {
109			case 1: goto mir_x;
110			case 2: goto mir_xy;
111			case 3: goto mir_y;
112			}
113			break;
114			case INP_QUAD2:
115			if ((90.-FTINY > phi) \| (phi > 180.+FTINY))
116			switch ((int)(phi*(1./90.))) {
117			case 0: goto mir_x;
118			case 2: goto mir_y;
119			case 3: goto mir_xy;
120			}
121			break;
122			case INP_QUAD3:
123			if ((180.-FTINY > phi) \| (phi > 270.+FTINY))
124			switch ((int)(phi*(1./90.))) {
125			case 0: goto mir_xy;
126			case 1: goto mir_y;
127			case 3: goto mir_x;
128			}
129			break;
130			case INP_QUAD4:
131			if ((270.-FTINY > phi) \| (phi > 360.+FTINY))
132			switch ((int)(phi*(1./90.))) {
133			case 0: goto mir_y;
134			case 1: goto mir_xy;
135			case 2: goto mir_x;
136			}
137			break;
138			default:
139			fprintf(stderr, "%s: Illegal input coverage (%d)\n",
140			progname, inp_coverage);
141			exit(1);
142			}
143			return(0); /* in range */
144			mir_x:
145			vec[0] = -vec[0];
146			return(MIRROR_X);
147			mir_y:
148			vec[1] = -vec[1];
149			return(MIRROR_Y);
150			mir_xy:
151			vec[0] = -vec[0];
152			vec[1] = -vec[1];
153			return(MIRROR_X\|MIRROR_Y);
154			}
155
156			/* Reverse symmetry based on what was done before */
157			void
158			rev_symmetry(FVECT vec, int sym)
159			{
160			if (sym & MIRROR_X)
161			vec[0] = -vec[0];
162			if (sym & MIRROR_Y)
163			vec[1] = -vec[1];
164			}
165
166			/* Reverse symmetry for an RBF distribution */
167			void
168			rev_rbf_symmetry(RBFNODE *rbf, int sym)
169			{
170			int n;
171
172			rev_symmetry(rbf->invec, sym);
173			if (sym & MIRROR_X)
174			for (n = rbf->nrbf; n-- > 0; )
175	greg	2.5	rbf->rbfa[n].gx = grid_res-1 - rbf->rbfa[n].gx;
176	greg	2.1	if (sym & MIRROR_Y)
177			for (n = rbf->nrbf; n-- > 0; )
178	greg	2.5	rbf->rbfa[n].gy = grid_res-1 - rbf->rbfa[n].gy;
179	greg	2.1	}
180
181	greg	2.6	/* Rotate RBF to correspond to given incident vector */
182			void
183			rotate_rbf(RBFNODE *rbf, const FVECT invec)
184			{
185			static const FVECT vnorm = {.0, .0, 1.};
186			const double phi = atan2(invec[1],invec[0]) -
187			atan2(rbf->invec[1],rbf->invec[0]);
188			FVECT outvec;
189			int pos[2];
190			int n;
191			#ifdef DEBUG
192			{
193			double tdiff = 180./M_PI*fabs(acos(invec[2])-acos(rbf->invec[2]));
194			if (tdiff >= 1.5)
195			fprintf(stderr,
196			"%s: Warning - rotated theta differs by %.1f degrees\n",
197			progname, tdiff);
198			}
199			#endif
200			for (n = rbf->nrbf; n-- > 0; ) {
201			ovec_from_pos(outvec, rbf->rbfa[n].gx, rbf->rbfa[n].gy);
202			spinvector(outvec, outvec, vnorm, phi);
203			pos_from_vec(pos, outvec);
204			rbf->rbfa[n].gx = pos[0];
205			rbf->rbfa[n].gy = pos[1];
206			}
207			VCOPY(rbf->invec, invec);
208			}
209
210	greg	2.1	/* Compute volume associated with Gaussian lobe */
211			double
212			rbf_volume(const RBFVAL *rbfp)
213			{
214			double rad = R2ANG(rbfp->crad);
215
216			return((2.M_PI) rbfp->peak * rad*rad);
217			}
218
219			/* Compute outgoing vector from grid position */
220			void
221			ovec_from_pos(FVECT vec, int xpos, int ypos)
222			{
223			double uv[2];
224			double r2;
225
226	greg	2.5	SDsquare2disk(uv, (1./grid_res)(xpos+.5), (1./grid_res)(ypos+.5));
227	greg	2.1	/* uniform hemispherical projection */
228			r2 = uv[0]uv[0] + uv[1]uv[1];
229			vec[0] = vec[1] = sqrt(2. - r2);
230			vec[0] *= uv[0];
231			vec[1] *= uv[1];
232			vec[2] = output_orient*(1. - r2);
233			}
234
235			/* Compute grid position from normalized input/output vector */
236			void
237			pos_from_vec(int pos[2], const FVECT vec)
238			{
239			double sq[2]; /* uniform hemispherical projection */
240			double norm = 1./sqrt(1. + fabs(vec[2]));
241
242			SDdisk2square(sq, vec[0]norm, vec[1]norm);
243
244	greg	2.5	pos[0] = (int)(sq[0]*grid_res);
245			pos[1] = (int)(sq[1]*grid_res);
246	greg	2.1	}
247
248			/* Evaluate RBF for DSF at the given normalized outgoing direction */
249			double
250			eval_rbfrep(const RBFNODE *rp, const FVECT outvec)
251			{
252			double res = .0;
253			const RBFVAL *rbfp;
254			FVECT odir;
255			double sig2;
256			int n;
257
258			if (rp == NULL)
259			return(.0);
260			rbfp = rp->rbfa;
261			for (n = rp->nrbf; n--; rbfp++) {
262			ovec_from_pos(odir, rbfp->gx, rbfp->gy);
263			sig2 = R2ANG(rbfp->crad);
264			sig2 = (DOT(odir,outvec) - 1.) / (sig2*sig2);
265			if (sig2 > -19.)
266			res += rbfp->peak * exp(sig2);
267			}
268			return(res);
269			}
270
271			/* Insert a new directional scattering function in our global list */
272			int
273			insert_dsf(RBFNODE *newrbf)
274			{
275			RBFNODE rbf, rbf_last;
276			int pos;
277			/* check for redundant meas. */
278			for (rbf = dsf_list; rbf != NULL; rbf = rbf->next)
279			if (DOT(rbf->invec, newrbf->invec) >= 1.-FTINY) {
280			fprintf(stderr,
281			"%s: Duplicate incident measurement (ignored)\n",
282			progname);
283			free(newrbf);
284			return(-1);
285			}
286			/* keep in ascending theta order */
287			for (rbf_last = NULL, rbf = dsf_list; rbf != NULL;
288			rbf_last = rbf, rbf = rbf->next)
289			if (single_plane_incident && input_orient*rbf->invec[2] <
290			input_orient*newrbf->invec[2])
291			break;
292			if (rbf_last == NULL) { /* insert new node in list */
293			newrbf->ord = 0;
294			newrbf->next = dsf_list;
295			dsf_list = newrbf;
296			} else {
297			newrbf->ord = rbf_last->ord + 1;
298			newrbf->next = rbf;
299			rbf_last->next = newrbf;
300			}
301			rbf_last = newrbf;
302			while (rbf != NULL) { /* update ordinal positions */
303			rbf->ord = rbf_last->ord + 1;
304			rbf_last = rbf;
305			rbf = rbf->next;
306			}
307			return(newrbf->ord);
308			}
309
310			/* Get the DSF indicated by its ordinal position */
311			RBFNODE *
312			get_dsf(int ord)
313			{
314			RBFNODE *rbf;
315
316			for (rbf = dsf_list; rbf != NULL; rbf = rbf->next)
317	greg	2.3	if (rbf->ord == ord)
318	greg	2.1	return(rbf);
319			return(NULL);
320			}
321
322			/* Get triangle surface orientation (unnormalized) */
323			void
324			tri_orient(FVECT vres, const FVECT v1, const FVECT v2, const FVECT v3)
325			{
326			FVECT v2minus1, v3minus2;
327
328			VSUB(v2minus1, v2, v1);
329			VSUB(v3minus2, v3, v2);
330			VCROSS(vres, v2minus1, v3minus2);
331			}
332
333			/* Determine if vertex order is reversed (inward normal) */
334			int
335			is_rev_tri(const FVECT v1, const FVECT v2, const FVECT v3)
336			{
337			FVECT tor;
338
339			tri_orient(tor, v1, v2, v3);
340
341			return(DOT(tor, v2) < 0.);
342			}
343
344			/* Find vertices completing triangles on either side of the given edge */
345			int
346			get_triangles(RBFNODE rbfv[2], const MIGRATION mig)
347			{
348	greg	2.4	const MIGRATION ej1, ej2;
349	greg	2.1	RBFNODE *tv;
350
351			rbfv[0] = rbfv[1] = NULL;
352			if (mig == NULL)
353			return(0);
354	greg	2.4	for (ej1 = mig->rbfv[0]->ejl; ej1 != NULL;
355			ej1 = nextedge(mig->rbfv[0],ej1)) {
356			if (ej1 == mig)
357	greg	2.1	continue;
358	greg	2.4	tv = opp_rbf(mig->rbfv[0],ej1);
359	greg	2.1	for (ej2 = tv->ejl; ej2 != NULL; ej2 = nextedge(tv,ej2))
360			if (opp_rbf(tv,ej2) == mig->rbfv[1]) {
361			rbfv[is_rev_tri(mig->rbfv[0]->invec,
362			mig->rbfv[1]->invec,
363			tv->invec)] = tv;
364			break;
365			}
366			}
367			return((rbfv[0] != NULL) + (rbfv[1] != NULL));
368			}
369
370	greg	2.4	/* Clear our BSDF representation and free memory */
371			void
372			clear_bsdf_rep(void)
373			{
374			while (mig_list != NULL) {
375			MIGRATION *mig = mig_list;
376			mig_list = mig->next;
377			free(mig);
378			}
379			while (dsf_list != NULL) {
380			RBFNODE *rbf = dsf_list;
381			dsf_list = rbf->next;
382			free(rbf);
383			}
384			inp_coverage = 0;
385			single_plane_incident = -1;
386			input_orient = output_orient = 0;
387	greg	2.5	grid_res = GRIDRES;
388	greg	2.4	}
389
390	greg	2.1	/* Write our BSDF mesh interpolant out to the given binary stream */
391			void
392			save_bsdf_rep(FILE *ofp)
393			{
394			RBFNODE *rbf;
395			MIGRATION *mig;
396			int i, n;
397			/* finish header */
398	greg	2.2	fprintf(ofp, "SYMMETRY=%d\n", !single_plane_incident * inp_coverage);
399			fprintf(ofp, "IO_SIDES= %d %d\n", input_orient, output_orient);
400	greg	2.5	fprintf(ofp, "GRIDRES=%d\n", grid_res);
401	greg	2.1	fputformat(BSDFREP_FMT, ofp);
402			fputc('\n', ofp);
403			/* write each DSF */
404			for (rbf = dsf_list; rbf != NULL; rbf = rbf->next) {
405			putint(rbf->ord, 4, ofp);
406			putflt(rbf->invec[0], ofp);
407			putflt(rbf->invec[1], ofp);
408			putflt(rbf->invec[2], ofp);
409			putflt(rbf->vtotal, ofp);
410			putint(rbf->nrbf, 4, ofp);
411			for (i = 0; i < rbf->nrbf; i++) {
412			putflt(rbf->rbfa[i].peak, ofp);
413			putint(rbf->rbfa[i].crad, 2, ofp);
414			putint(rbf->rbfa[i].gx, 1, ofp);
415			putint(rbf->rbfa[i].gy, 1, ofp);
416			}
417			}
418			putint(-1, 4, ofp); /* terminator */
419			/* write each migration matrix */
420	greg	2.2	for (mig = mig_list; mig != NULL; mig = mig->next) {
421			int zerocnt = 0;
422	greg	2.1	putint(mig->rbfv[0]->ord, 4, ofp);
423			putint(mig->rbfv[1]->ord, 4, ofp);
424	greg	2.2	/* write out as sparse data */
425	greg	2.1	n = mtx_nrows(mig) * mtx_ncols(mig);
426	greg	2.2	for (i = 0; i < n; i++) {
427	greg	2.3	if (zerocnt == 0xff) {
428			putint(0xff, 1, ofp); zerocnt = 0;
429	greg	2.2	}
430			if (mig->mtx[i] != 0) {
431			putint(zerocnt, 1, ofp); zerocnt = 0;
432			putflt(mig->mtx[i], ofp);
433			} else
434			++zerocnt;
435			}
436			putint(zerocnt, 1, ofp);
437	greg	2.1	}
438			putint(-1, 4, ofp); /* terminator */
439			putint(-1, 4, ofp);
440			if (fflush(ofp) == EOF) {
441			fprintf(stderr, "%s: error writing BSDF interpolant\n",
442			progname);
443			exit(1);
444			}
445			}
446
447	greg	2.2	/* Check header line for critical information */
448			static int
449			headline(char s, void p)
450			{
451			char fmt[32];
452
453			if (!strncmp(s, "SYMMETRY=", 9)) {
454			inp_coverage = atoi(s+9);
455			single_plane_incident = !inp_coverage;
456			return(0);
457			}
458			if (!strncmp(s, "IO_SIDES=", 9)) {
459			sscanf(s+9, "%d %d", &input_orient, &output_orient);
460			return(0);
461			}
462	greg	2.5	if (!strncmp(s, "GRIDRES=", 8)) {
463			sscanf(s+8, "%d", &grid_res);
464			return(0);
465			}
466	greg	2.2	if (formatval(fmt, s) && strcmp(fmt, BSDFREP_FMT))
467			return(-1);
468			return(0);
469			}
470
471	greg	2.1	/* Read a BSDF mesh interpolant from the given binary stream */
472			int
473			load_bsdf_rep(FILE *ifp)
474			{
475			RBFNODE rbfh;
476			int from_ord, to_ord;
477			int i;
478	greg	2.4
479			clear_bsdf_rep();
480	greg	2.5	if (ifp == NULL)
481			return(0);
482	greg	2.2	if (getheader(ifp, headline, NULL) < 0 \|\| single_plane_incident < 0 \|
483			!input_orient \| !output_orient) {
484	greg	2.1	fprintf(stderr, "%s: missing/bad format for BSDF interpolant\n",
485			progname);
486			return(0);
487			}
488			rbfh.next = NULL; /* read each DSF */
489			rbfh.ejl = NULL;
490			while ((rbfh.ord = getint(4, ifp)) >= 0) {
491			RBFNODE *newrbf;
492
493			rbfh.invec[0] = getflt(ifp);
494			rbfh.invec[1] = getflt(ifp);
495			rbfh.invec[2] = getflt(ifp);
496	greg	2.3	rbfh.vtotal = getflt(ifp);
497	greg	2.1	rbfh.nrbf = getint(4, ifp);
498			newrbf = (RBFNODE *)malloc(sizeof(RBFNODE) +
499			sizeof(RBFVAL)*(rbfh.nrbf-1));
500			if (newrbf == NULL)
501			goto memerr;
502			memcpy(newrbf, &rbfh, sizeof(RBFNODE));
503			for (i = 0; i < rbfh.nrbf; i++) {
504			newrbf->rbfa[i].peak = getflt(ifp);
505			newrbf->rbfa[i].crad = getint(2, ifp) & 0xffff;
506			newrbf->rbfa[i].gx = getint(1, ifp) & 0xff;
507			newrbf->rbfa[i].gy = getint(1, ifp) & 0xff;
508			}
509			if (feof(ifp))
510			goto badEOF;
511			/* insert in global list */
512			if (insert_dsf(newrbf) != rbfh.ord) {
513			fprintf(stderr, "%s: error adding DSF\n", progname);
514			return(0);
515			}
516			}
517			/* read each migration matrix */
518			while ((from_ord = getint(4, ifp)) >= 0 &&
519			(to_ord = getint(4, ifp)) >= 0) {
520			RBFNODE *from_rbf = get_dsf(from_ord);
521			RBFNODE *to_rbf = get_dsf(to_ord);
522			MIGRATION *newmig;
523			int n;
524
525			if ((from_rbf == NULL) \| (to_rbf == NULL)) {
526			fprintf(stderr,
527			"%s: bad DSF reference in migration edge\n",
528			progname);
529			return(0);
530			}
531			n = from_rbf->nrbf * to_rbf->nrbf;
532			newmig = (MIGRATION *)malloc(sizeof(MIGRATION) +
533			sizeof(float)*(n-1));
534			if (newmig == NULL)
535			goto memerr;
536			newmig->rbfv[0] = from_rbf;
537			newmig->rbfv[1] = to_rbf;
538	greg	2.2	memset(newmig->mtx, 0, sizeof(float)*n);
539			for (i = 0; ; ) { /* read sparse data */
540			int zc = getint(1, ifp) & 0xff;
541			if ((i += zc) >= n)
542			break;
543	greg	2.3	if (zc == 0xff)
544			continue;
545	greg	2.2	newmig->mtx[i++] = getflt(ifp);
546			}
547	greg	2.1	if (feof(ifp))
548			goto badEOF;
549			/* insert in edge lists */
550			newmig->enxt[0] = from_rbf->ejl;
551			from_rbf->ejl = newmig;
552			newmig->enxt[1] = to_rbf->ejl;
553			to_rbf->ejl = newmig;
554			/* push onto global list */
555			newmig->next = mig_list;
556			mig_list = newmig;
557			}
558			return(1); /* success! */
559			memerr:
560			fprintf(stderr, "%s: Out of memory in load_bsdf_rep()\n", progname);
561			exit(1);
562			badEOF:
563			fprintf(stderr, "%s: Unexpected EOF in load_bsdf_rep()\n", progname);
564			return(0);
565			}