src/cv/bsdfrep.c

#ifndef lint
static const char RCSid[] = "$Id: bsdfrep.c,v 2.14 2013/09/20 00:21:39 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;

                                /* 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)
{
        double          minval = bsdf_min*output_orient*outvec[2];
        double          res = 0;
        const RBFVAL    *rbfp;
        FVECT           odir;
        double          sig2;
        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);
                                /* sum radial basis function */
        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);
        }
        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);
        }
        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);
        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, "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);
        }
        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);
                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;
                memcpy(newrbf, &rbfh, sizeof(RBFNODE)-sizeof(RBFVAL));
                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:	2.15
Committed:	Sat Oct 19 00:11:50 2013 UTC (10 years, 6 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.14:	+2 -2 lines
Log Message:	Fixed overflow and tweaked culling operations
#	User	Rev	Content
1	greg	2.1	#ifndef lint
2	greg	2.15	static const char RCSid[] = "$Id: bsdfrep.c,v 2.14 2013/09/20 00:21:39 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	greg	2.12	/* BSDF histogram */
30	greg	2.15	unsigned long bsdf_hist[HISTLEN];
31	greg	2.12
32			/* BSDF value for boundary regions */
33			double bsdf_min = 0;
34
35	greg	2.1	/* processed incident DSF measurements */
36			RBFNODE *dsf_list = NULL;
37
38			/* RBF-linking matrices (edges) */
39			MIGRATION *mig_list = NULL;
40
41			/* current input direction */
42			double theta_in_deg, phi_in_deg;
43
44			/* Register new input direction */
45			int
46			new_input_direction(double new_theta, double new_phi)
47			{
48			if (!input_orient) /* check input orientation */
49			input_orient = 1 - 2*(new_theta > 90.);
50			else if (input_orient > 0 ^ new_theta < 90.) {
51			fprintf(stderr,
52			"%s: Cannot handle input angles on both sides of surface\n",
53			progname);
54			return(0);
55			}
56			/* normalize angle ranges */
57			while (new_theta < -180.)
58			new_theta += 360.;
59			while (new_theta > 180.)
60			new_theta -= 360.;
61			if (new_theta < 0) {
62			new_theta = -new_theta;
63			new_phi += 180.;
64			}
65	greg	2.6	if ((theta_in_deg = new_theta) < 1.0)
66			return(1); /* don't rely on phi near normal */
67	greg	2.1	while (new_phi < 0)
68			new_phi += 360.;
69			while (new_phi >= 360.)
70			new_phi -= 360.;
71			if (single_plane_incident > 0) /* check input coverage */
72			single_plane_incident = (round(new_phi) == round(phi_in_deg));
73			else if (single_plane_incident < 0)
74			single_plane_incident = 1;
75			phi_in_deg = new_phi;
76			if ((1. < new_phi) & (new_phi < 89.))
77			inp_coverage \|= INP_QUAD1;
78			else if ((91. < new_phi) & (new_phi < 179.))
79			inp_coverage \|= INP_QUAD2;
80			else if ((181. < new_phi) & (new_phi < 269.))
81			inp_coverage \|= INP_QUAD3;
82			else if ((271. < new_phi) & (new_phi < 359.))
83			inp_coverage \|= INP_QUAD4;
84			return(1);
85			}
86
87			/* Apply symmetry to the given vector based on distribution */
88			int
89			use_symmetry(FVECT vec)
90			{
91	greg	2.11	const double phi = get_phi360(vec);
92	greg	2.1
93			switch (inp_coverage) {
94			case INP_QUAD1\|INP_QUAD2\|INP_QUAD3\|INP_QUAD4:
95			break;
96			case INP_QUAD1\|INP_QUAD2:
97			if ((-FTINY > phi) \| (phi > 180.+FTINY))
98			goto mir_y;
99			break;
100			case INP_QUAD2\|INP_QUAD3:
101			if ((90.-FTINY > phi) \| (phi > 270.+FTINY))
102			goto mir_x;
103			break;
104			case INP_QUAD3\|INP_QUAD4:
105			if ((180.-FTINY > phi) \| (phi > 360.+FTINY))
106			goto mir_y;
107			break;
108			case INP_QUAD4\|INP_QUAD1:
109			if ((270.-FTINY > phi) & (phi > 90.+FTINY))
110			goto mir_x;
111			break;
112			case INP_QUAD1:
113			if ((-FTINY > phi) \| (phi > 90.+FTINY))
114			switch ((int)(phi*(1./90.))) {
115			case 1: goto mir_x;
116			case 2: goto mir_xy;
117			case 3: goto mir_y;
118			}
119			break;
120			case INP_QUAD2:
121			if ((90.-FTINY > phi) \| (phi > 180.+FTINY))
122			switch ((int)(phi*(1./90.))) {
123			case 0: goto mir_x;
124			case 2: goto mir_y;
125			case 3: goto mir_xy;
126			}
127			break;
128			case INP_QUAD3:
129			if ((180.-FTINY > phi) \| (phi > 270.+FTINY))
130			switch ((int)(phi*(1./90.))) {
131			case 0: goto mir_xy;
132			case 1: goto mir_y;
133			case 3: goto mir_x;
134			}
135			break;
136			case INP_QUAD4:
137			if ((270.-FTINY > phi) \| (phi > 360.+FTINY))
138			switch ((int)(phi*(1./90.))) {
139			case 0: goto mir_y;
140			case 1: goto mir_xy;
141			case 2: goto mir_x;
142			}
143			break;
144			default:
145			fprintf(stderr, "%s: Illegal input coverage (%d)\n",
146			progname, inp_coverage);
147			exit(1);
148			}
149			return(0); /* in range */
150			mir_x:
151			vec[0] = -vec[0];
152			return(MIRROR_X);
153			mir_y:
154			vec[1] = -vec[1];
155			return(MIRROR_Y);
156			mir_xy:
157			vec[0] = -vec[0];
158			vec[1] = -vec[1];
159			return(MIRROR_X\|MIRROR_Y);
160			}
161
162			/* Reverse symmetry based on what was done before */
163			void
164			rev_symmetry(FVECT vec, int sym)
165			{
166			if (sym & MIRROR_X)
167			vec[0] = -vec[0];
168			if (sym & MIRROR_Y)
169			vec[1] = -vec[1];
170			}
171
172			/* Reverse symmetry for an RBF distribution */
173			void
174			rev_rbf_symmetry(RBFNODE *rbf, int sym)
175			{
176			int n;
177
178			rev_symmetry(rbf->invec, sym);
179			if (sym & MIRROR_X)
180			for (n = rbf->nrbf; n-- > 0; )
181	greg	2.5	rbf->rbfa[n].gx = grid_res-1 - rbf->rbfa[n].gx;
182	greg	2.1	if (sym & MIRROR_Y)
183			for (n = rbf->nrbf; n-- > 0; )
184	greg	2.5	rbf->rbfa[n].gy = grid_res-1 - rbf->rbfa[n].gy;
185	greg	2.1	}
186
187	greg	2.6	/* Rotate RBF to correspond to given incident vector */
188			void
189			rotate_rbf(RBFNODE *rbf, const FVECT invec)
190			{
191			static const FVECT vnorm = {.0, .0, 1.};
192			const double phi = atan2(invec[1],invec[0]) -
193			atan2(rbf->invec[1],rbf->invec[0]);
194			FVECT outvec;
195			int pos[2];
196			int n;
197	greg	2.8
198	greg	2.10	for (n = ((-.01 > phi) \| (phi > .01))*rbf->nrbf; n-- > 0; ) {
199	greg	2.6	ovec_from_pos(outvec, rbf->rbfa[n].gx, rbf->rbfa[n].gy);
200			spinvector(outvec, outvec, vnorm, phi);
201			pos_from_vec(pos, outvec);
202			rbf->rbfa[n].gx = pos[0];
203			rbf->rbfa[n].gy = pos[1];
204			}
205			VCOPY(rbf->invec, invec);
206			}
207
208	greg	2.1	/* Compute outgoing vector from grid position */
209			void
210			ovec_from_pos(FVECT vec, int xpos, int ypos)
211			{
212			double uv[2];
213			double r2;
214
215	greg	2.8	SDsquare2disk(uv, (xpos+.5)/grid_res, (ypos+.5)/grid_res);
216	greg	2.1	/* uniform hemispherical projection */
217			r2 = uv[0]uv[0] + uv[1]uv[1];
218			vec[0] = vec[1] = sqrt(2. - r2);
219			vec[0] *= uv[0];
220			vec[1] *= uv[1];
221			vec[2] = output_orient*(1. - r2);
222			}
223
224			/* Compute grid position from normalized input/output vector */
225			void
226			pos_from_vec(int pos[2], const FVECT vec)
227			{
228			double sq[2]; /* uniform hemispherical projection */
229			double norm = 1./sqrt(1. + fabs(vec[2]));
230
231			SDdisk2square(sq, vec[0]norm, vec[1]norm);
232
233	greg	2.5	pos[0] = (int)(sq[0]*grid_res);
234			pos[1] = (int)(sq[1]*grid_res);
235	greg	2.1	}
236
237	greg	2.14	/* Compute volume associated with Gaussian lobe */
238			double
239			rbf_volume(const RBFVAL *rbfp)
240			{
241			double rad = R2ANG(rbfp->crad);
242			FVECT odir;
243			double elev, integ;
244			/* infinite integral approximation */
245			integ = (2.M_PI) rbfp->peak * rad*rad;
246			/* check if we're near horizon */
247			ovec_from_pos(odir, rbfp->gx, rbfp->gy);
248			elev = output_orient*odir[2];
249			/* apply cut-off correction if > 1% */
250			if (elev < 2.8*rad) {
251			/* elev = asin(elev); /* this is so crude, anyway... */
252			integ = 1. - .5exp(-.5elevelev/(rad*rad));
253			}
254			return(integ);
255			}
256
257	greg	2.1	/* Evaluate RBF for DSF at the given normalized outgoing direction */
258			double
259			eval_rbfrep(const RBFNODE *rp, const FVECT outvec)
260			{
261	greg	2.13	double minval = bsdf_minoutput_orientoutvec[2];
262	greg	2.8	double res = 0;
263	greg	2.1	const RBFVAL *rbfp;
264			FVECT odir;
265			double sig2;
266			int n;
267	greg	2.14	/* check for wrong side */
268			if (outvec[2] > 0 ^ output_orient > 0)
269			return(.0);
270	greg	2.12	/* use minimum if no information avail. */
271	greg	2.14	if (rp == NULL)
272	greg	2.13	return(minval);
273	greg	2.14	/* sum radial basis function */
274	greg	2.1	rbfp = rp->rbfa;
275			for (n = rp->nrbf; n--; rbfp++) {
276			ovec_from_pos(odir, rbfp->gx, rbfp->gy);
277			sig2 = R2ANG(rbfp->crad);
278			sig2 = (DOT(odir,outvec) - 1.) / (sig2*sig2);
279			if (sig2 > -19.)
280			res += rbfp->peak * exp(sig2);
281			}
282	greg	2.13	if (res < minval) /* never return less than minval */
283			return(minval);
284	greg	2.1	return(res);
285			}
286
287			/* Insert a new directional scattering function in our global list */
288			int
289			insert_dsf(RBFNODE *newrbf)
290			{
291			RBFNODE rbf, rbf_last;
292			int pos;
293			/* check for redundant meas. */
294			for (rbf = dsf_list; rbf != NULL; rbf = rbf->next)
295			if (DOT(rbf->invec, newrbf->invec) >= 1.-FTINY) {
296			fprintf(stderr,
297			"%s: Duplicate incident measurement (ignored)\n",
298			progname);
299			free(newrbf);
300			return(-1);
301			}
302			/* keep in ascending theta order */
303			for (rbf_last = NULL, rbf = dsf_list; rbf != NULL;
304			rbf_last = rbf, rbf = rbf->next)
305			if (single_plane_incident && input_orient*rbf->invec[2] <
306			input_orient*newrbf->invec[2])
307			break;
308			if (rbf_last == NULL) { /* insert new node in list */
309			newrbf->ord = 0;
310			newrbf->next = dsf_list;
311			dsf_list = newrbf;
312			} else {
313			newrbf->ord = rbf_last->ord + 1;
314			newrbf->next = rbf;
315			rbf_last->next = newrbf;
316			}
317			rbf_last = newrbf;
318			while (rbf != NULL) { /* update ordinal positions */
319			rbf->ord = rbf_last->ord + 1;
320			rbf_last = rbf;
321			rbf = rbf->next;
322			}
323			return(newrbf->ord);
324			}
325
326			/* Get the DSF indicated by its ordinal position */
327			RBFNODE *
328			get_dsf(int ord)
329			{
330			RBFNODE *rbf;
331
332			for (rbf = dsf_list; rbf != NULL; rbf = rbf->next)
333	greg	2.3	if (rbf->ord == ord)
334	greg	2.1	return(rbf);
335			return(NULL);
336			}
337
338			/* Get triangle surface orientation (unnormalized) */
339			void
340			tri_orient(FVECT vres, const FVECT v1, const FVECT v2, const FVECT v3)
341			{
342			FVECT v2minus1, v3minus2;
343
344			VSUB(v2minus1, v2, v1);
345			VSUB(v3minus2, v3, v2);
346			VCROSS(vres, v2minus1, v3minus2);
347			}
348
349			/* Determine if vertex order is reversed (inward normal) */
350			int
351			is_rev_tri(const FVECT v1, const FVECT v2, const FVECT v3)
352			{
353			FVECT tor;
354
355			tri_orient(tor, v1, v2, v3);
356
357			return(DOT(tor, v2) < 0.);
358			}
359
360			/* Find vertices completing triangles on either side of the given edge */
361			int
362			get_triangles(RBFNODE rbfv[2], const MIGRATION mig)
363			{
364	greg	2.4	const MIGRATION ej1, ej2;
365	greg	2.1	RBFNODE *tv;
366
367			rbfv[0] = rbfv[1] = NULL;
368			if (mig == NULL)
369			return(0);
370	greg	2.4	for (ej1 = mig->rbfv[0]->ejl; ej1 != NULL;
371			ej1 = nextedge(mig->rbfv[0],ej1)) {
372			if (ej1 == mig)
373	greg	2.1	continue;
374	greg	2.4	tv = opp_rbf(mig->rbfv[0],ej1);
375	greg	2.1	for (ej2 = tv->ejl; ej2 != NULL; ej2 = nextedge(tv,ej2))
376			if (opp_rbf(tv,ej2) == mig->rbfv[1]) {
377			rbfv[is_rev_tri(mig->rbfv[0]->invec,
378			mig->rbfv[1]->invec,
379			tv->invec)] = tv;
380			break;
381			}
382			}
383			return((rbfv[0] != NULL) + (rbfv[1] != NULL));
384			}
385
386	greg	2.4	/* Clear our BSDF representation and free memory */
387			void
388			clear_bsdf_rep(void)
389			{
390			while (mig_list != NULL) {
391			MIGRATION *mig = mig_list;
392			mig_list = mig->next;
393			free(mig);
394			}
395			while (dsf_list != NULL) {
396			RBFNODE *rbf = dsf_list;
397			dsf_list = rbf->next;
398			free(rbf);
399			}
400			inp_coverage = 0;
401			single_plane_incident = -1;
402			input_orient = output_orient = 0;
403	greg	2.5	grid_res = GRIDRES;
404	greg	2.4	}
405
406	greg	2.1	/* Write our BSDF mesh interpolant out to the given binary stream */
407			void
408			save_bsdf_rep(FILE *ofp)
409			{
410			RBFNODE *rbf;
411			MIGRATION *mig;
412			int i, n;
413			/* finish header */
414	greg	2.2	fprintf(ofp, "SYMMETRY=%d\n", !single_plane_incident * inp_coverage);
415			fprintf(ofp, "IO_SIDES= %d %d\n", input_orient, output_orient);
416	greg	2.5	fprintf(ofp, "GRIDRES=%d\n", grid_res);
417	greg	2.12	fprintf(ofp, "BSDFMIN=%g\n", bsdf_min);
418	greg	2.1	fputformat(BSDFREP_FMT, ofp);
419			fputc('\n', ofp);
420			/* write each DSF */
421			for (rbf = dsf_list; rbf != NULL; rbf = rbf->next) {
422			putint(rbf->ord, 4, ofp);
423			putflt(rbf->invec[0], ofp);
424			putflt(rbf->invec[1], ofp);
425			putflt(rbf->invec[2], ofp);
426			putflt(rbf->vtotal, ofp);
427			putint(rbf->nrbf, 4, ofp);
428			for (i = 0; i < rbf->nrbf; i++) {
429			putflt(rbf->rbfa[i].peak, ofp);
430			putint(rbf->rbfa[i].crad, 2, ofp);
431			putint(rbf->rbfa[i].gx, 1, ofp);
432			putint(rbf->rbfa[i].gy, 1, ofp);
433			}
434			}
435			putint(-1, 4, ofp); /* terminator */
436			/* write each migration matrix */
437	greg	2.2	for (mig = mig_list; mig != NULL; mig = mig->next) {
438			int zerocnt = 0;
439	greg	2.1	putint(mig->rbfv[0]->ord, 4, ofp);
440			putint(mig->rbfv[1]->ord, 4, ofp);
441	greg	2.2	/* write out as sparse data */
442	greg	2.1	n = mtx_nrows(mig) * mtx_ncols(mig);
443	greg	2.2	for (i = 0; i < n; i++) {
444	greg	2.3	if (zerocnt == 0xff) {
445			putint(0xff, 1, ofp); zerocnt = 0;
446	greg	2.2	}
447			if (mig->mtx[i] != 0) {
448			putint(zerocnt, 1, ofp); zerocnt = 0;
449			putflt(mig->mtx[i], ofp);
450			} else
451			++zerocnt;
452			}
453			putint(zerocnt, 1, ofp);
454	greg	2.1	}
455			putint(-1, 4, ofp); /* terminator */
456			putint(-1, 4, ofp);
457			if (fflush(ofp) == EOF) {
458			fprintf(stderr, "%s: error writing BSDF interpolant\n",
459			progname);
460			exit(1);
461			}
462			}
463
464	greg	2.2	/* Check header line for critical information */
465			static int
466			headline(char s, void p)
467			{
468			char fmt[32];
469
470			if (!strncmp(s, "SYMMETRY=", 9)) {
471			inp_coverage = atoi(s+9);
472			single_plane_incident = !inp_coverage;
473			return(0);
474			}
475			if (!strncmp(s, "IO_SIDES=", 9)) {
476			sscanf(s+9, "%d %d", &input_orient, &output_orient);
477			return(0);
478			}
479	greg	2.5	if (!strncmp(s, "GRIDRES=", 8)) {
480			sscanf(s+8, "%d", &grid_res);
481			return(0);
482			}
483	greg	2.12	if (!strncmp(s, "BSDFMIN=", 8)) {
484			sscanf(s+8, "%lf", &bsdf_min);
485			return(0);
486			}
487	greg	2.2	if (formatval(fmt, s) && strcmp(fmt, BSDFREP_FMT))
488			return(-1);
489			return(0);
490			}
491
492	greg	2.1	/* Read a BSDF mesh interpolant from the given binary stream */
493			int
494			load_bsdf_rep(FILE *ifp)
495			{
496			RBFNODE rbfh;
497			int from_ord, to_ord;
498			int i;
499	greg	2.4
500			clear_bsdf_rep();
501	greg	2.5	if (ifp == NULL)
502			return(0);
503	greg	2.2	if (getheader(ifp, headline, NULL) < 0 \|\| single_plane_incident < 0 \|
504			!input_orient \| !output_orient) {
505	greg	2.1	fprintf(stderr, "%s: missing/bad format for BSDF interpolant\n",
506			progname);
507			return(0);
508			}
509			rbfh.next = NULL; /* read each DSF */
510			rbfh.ejl = NULL;
511			while ((rbfh.ord = getint(4, ifp)) >= 0) {
512			RBFNODE *newrbf;
513
514			rbfh.invec[0] = getflt(ifp);
515			rbfh.invec[1] = getflt(ifp);
516			rbfh.invec[2] = getflt(ifp);
517	greg	2.9	if (normalize(rbfh.invec) == 0) {
518			fprintf(stderr, "%s: zero incident vector\n", progname);
519			return(0);
520			}
521	greg	2.3	rbfh.vtotal = getflt(ifp);
522	greg	2.1	rbfh.nrbf = getint(4, ifp);
523			newrbf = (RBFNODE *)malloc(sizeof(RBFNODE) +
524			sizeof(RBFVAL)*(rbfh.nrbf-1));
525			if (newrbf == NULL)
526			goto memerr;
527	greg	2.8	memcpy(newrbf, &rbfh, sizeof(RBFNODE)-sizeof(RBFVAL));
528	greg	2.1	for (i = 0; i < rbfh.nrbf; i++) {
529			newrbf->rbfa[i].peak = getflt(ifp);
530			newrbf->rbfa[i].crad = getint(2, ifp) & 0xffff;
531			newrbf->rbfa[i].gx = getint(1, ifp) & 0xff;
532			newrbf->rbfa[i].gy = getint(1, ifp) & 0xff;
533			}
534			if (feof(ifp))
535			goto badEOF;
536			/* insert in global list */
537			if (insert_dsf(newrbf) != rbfh.ord) {
538			fprintf(stderr, "%s: error adding DSF\n", progname);
539			return(0);
540			}
541			}
542			/* read each migration matrix */
543			while ((from_ord = getint(4, ifp)) >= 0 &&
544			(to_ord = getint(4, ifp)) >= 0) {
545			RBFNODE *from_rbf = get_dsf(from_ord);
546			RBFNODE *to_rbf = get_dsf(to_ord);
547			MIGRATION *newmig;
548			int n;
549
550			if ((from_rbf == NULL) \| (to_rbf == NULL)) {
551			fprintf(stderr,
552			"%s: bad DSF reference in migration edge\n",
553			progname);
554			return(0);
555			}
556			n = from_rbf->nrbf * to_rbf->nrbf;
557			newmig = (MIGRATION *)malloc(sizeof(MIGRATION) +
558			sizeof(float)*(n-1));
559			if (newmig == NULL)
560			goto memerr;
561			newmig->rbfv[0] = from_rbf;
562			newmig->rbfv[1] = to_rbf;
563	greg	2.2	memset(newmig->mtx, 0, sizeof(float)*n);
564			for (i = 0; ; ) { /* read sparse data */
565			int zc = getint(1, ifp) & 0xff;
566			if ((i += zc) >= n)
567			break;
568	greg	2.3	if (zc == 0xff)
569			continue;
570	greg	2.2	newmig->mtx[i++] = getflt(ifp);
571			}
572	greg	2.1	if (feof(ifp))
573			goto badEOF;
574			/* insert in edge lists */
575			newmig->enxt[0] = from_rbf->ejl;
576			from_rbf->ejl = newmig;
577			newmig->enxt[1] = to_rbf->ejl;
578			to_rbf->ejl = newmig;
579			/* push onto global list */
580			newmig->next = mig_list;
581			mig_list = newmig;
582			}
583			return(1); /* success! */
584			memerr:
585			fprintf(stderr, "%s: Out of memory in load_bsdf_rep()\n", progname);
586			exit(1);
587			badEOF:
588			fprintf(stderr, "%s: Unexpected EOF in load_bsdf_rep()\n", progname);
589			return(0);
590			}