src/cv/bsdfinterp.c

#ifndef lint
static const char RCSid[] = "$Id: bsdfinterp.c,v 2.15 2013/10/23 03:41:39 greg Exp $";
#endif
/*
 * Interpolate BSDF data from radial basis functions in advection mesh.
 *
 *      G. Ward
 */

#define _USE_MATH_DEFINES
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "bsdfrep.h"

/* Insert vertex in ordered list */
static void
insert_vert(RBFNODE **vlist, RBFNODE *v)
{
        int     i, j;

        for (i = 0; vlist[i] != NULL; i++) {
                if (v == vlist[i])
                        return;
                if (v->ord < vlist[i]->ord)
                        break;
        }
        for (j = i; vlist[j] != NULL; j++)
                ;
        while (j > i) {
                vlist[j] = vlist[j-1];
                --j;
        }
        vlist[i] = v;
}

/* Sort triangle edges in standard order */
static int
order_triangle(MIGRATION *miga[3])
{
        RBFNODE         *vert[7];
        MIGRATION       *ord[3];
        int             i;
                                                /* order vertices, first */
        memset(vert, 0, sizeof(vert));
        for (i = 3; i--; ) {
                if (miga[i] == NULL)
                        return(0);
                insert_vert(vert, miga[i]->rbfv[0]);
                insert_vert(vert, miga[i]->rbfv[1]);
        }
                                                /* should be just 3 vertices */
        if ((vert[2] == NULL) | (vert[3] != NULL))
                return(0);
                                                /* identify edge 0 */
        for (i = 3; i--; )
                if (miga[i]->rbfv[0] == vert[0] &&
                                miga[i]->rbfv[1] == vert[1]) {
                        ord[0] = miga[i];
                        break;
                }
        if (i < 0)
                return(0);
                                                /* identify edge 1 */
        for (i = 3; i--; )
                if (miga[i]->rbfv[0] == vert[1] &&
                                miga[i]->rbfv[1] == vert[2]) {
                        ord[1] = miga[i];
                        break;
                }
        if (i < 0)
                return(0);
                                                /* identify edge 2 */
        for (i = 3; i--; )
                if (miga[i]->rbfv[0] == vert[0] &&
                                miga[i]->rbfv[1] == vert[2]) {
                        ord[2] = miga[i];
                        break;
                }
        if (i < 0)
                return(0);
                                                /* reassign order */
        miga[0] = ord[0]; miga[1] = ord[1]; miga[2] = ord[2];
        return(1);
}

/* Determine if we are close enough to an edge */
static int
on_edge(const MIGRATION *ej, const FVECT ivec)
{
        double  cos_a, cos_b, cos_c, cos_aplusb;
                                        /* use triangle inequality */
        cos_a = DOT(ej->rbfv[0]->invec, ivec);
        if (cos_a <= 0)
                return(0);
        if (cos_a >= 1.)                /* handles rounding error */
                return(1);

        cos_b = DOT(ej->rbfv[1]->invec, ivec);
        if (cos_b <= 0)
                return(0);
        if (cos_b >= 1.)
                return(1);

        cos_aplusb = cos_a*cos_b - sqrt((1.-cos_a*cos_a)*(1.-cos_b*cos_b));
        if (cos_aplusb <= 0)
                return(0);

        cos_c = DOT(ej->rbfv[0]->invec, ej->rbfv[1]->invec);

        return(cos_c - cos_aplusb < .001);
}

/* Determine if we are inside the given triangle */
static int
in_tri(const RBFNODE *v1, const RBFNODE *v2, const RBFNODE *v3, const FVECT p)
{
        FVECT   vc;
        int     sgn1, sgn2, sgn3;
                                        /* signed volume test */
        VCROSS(vc, v1->invec, v2->invec);
        sgn1 = (DOT(p, vc) > 0);
        VCROSS(vc, v2->invec, v3->invec);
        sgn2 = (DOT(p, vc) > 0);
        if (sgn1 != sgn2)
                return(0);
        VCROSS(vc, v3->invec, v1->invec);
        sgn3 = (DOT(p, vc) > 0);
        return(sgn2 == sgn3);
}

/* Test (and set) bitmap for edge */
static int
check_edge(unsigned char *emap, int nedges, const MIGRATION *mig, int mark)
{
        int     ejndx, bit2check;

        if (mig->rbfv[0]->ord > mig->rbfv[1]->ord)
                ejndx = mig->rbfv[1]->ord + (nedges-1)*mig->rbfv[0]->ord;
        else
                ejndx = mig->rbfv[0]->ord + (nedges-1)*mig->rbfv[1]->ord;

        bit2check = 1<<(ejndx&07);

        if (emap[ejndx>>3] & bit2check)
                return(0);
        if (mark)
                emap[ejndx>>3] |= bit2check;
        return(1);
}

/* Compute intersection with the given position over remaining mesh */
static int
in_mesh(MIGRATION *miga[3], unsigned char *emap, int nedges,
                        const FVECT ivec, MIGRATION *mig)
{
        RBFNODE         *tv[2];
        MIGRATION       *sej[2], *dej[2];
        int             i;
                                                /* check visitation record */
        if (!check_edge(emap, nedges, mig, 1))
                return(0);
        if (on_edge(mig, ivec)) {
                miga[0] = mig;                  /* close enough to edge */
                return(1);
        }
        if (!get_triangles(tv, mig))            /* do triangles either side? */
                return(0);
        for (i = 2; i--; ) {                    /* identify edges to check */
                MIGRATION       *ej;
                sej[i] = dej[i] = NULL;
                if (tv[i] == NULL)
                        continue;
                for (ej = tv[i]->ejl; ej != NULL; ej = nextedge(tv[i],ej)) {
                        RBFNODE *rbfop = opp_rbf(tv[i],ej);
                        if (rbfop == mig->rbfv[0]) {
                                if (check_edge(emap, nedges, ej, 0))
                                        sej[i] = ej;
                        } else if (rbfop == mig->rbfv[1]) {
                                if (check_edge(emap, nedges, ej, 0))
                                        dej[i] = ej;
                        }
                }
        }
        for (i = 2; i--; ) {                    /* check triangles just once */
                if (sej[i] != NULL && in_mesh(miga, emap, nedges, ivec, sej[i]))
                        return(1);
                if (dej[i] != NULL && in_mesh(miga, emap, nedges, ivec, dej[i]))
                        return(1);
                if ((sej[i] == NULL) | (dej[i] == NULL))
                        continue;
                if (in_tri(mig->rbfv[0], mig->rbfv[1], tv[i], ivec)) {
                        miga[0] = mig;
                        miga[1] = sej[i];
                        miga[2] = dej[i];
                        return(1);
                }
        }
        return(0);                              /* not near this edge */
}

/* Find edge(s) for interpolating the given vector, applying symmetry */
int
get_interp(MIGRATION *miga[3], FVECT invec)
{
        miga[0] = miga[1] = miga[2] = NULL;
        if (single_plane_incident) {            /* isotropic BSDF? */
            RBFNODE     *rbf;                   /* find edge we're on */
            for (rbf = dsf_list; rbf != NULL; rbf = rbf->next) {
                if (input_orient*rbf->invec[2] < input_orient*invec[2]-FTINY)
                        break;
                if (rbf->next != NULL && input_orient*rbf->next->invec[2] <
                                                input_orient*invec[2]+FTINY) {
                    for (miga[0] = rbf->ejl; miga[0] != NULL;
                                        miga[0] = nextedge(rbf,miga[0]))
                        if (opp_rbf(rbf,miga[0]) == rbf->next) {
                                double  nf = 1. - rbf->invec[2]*rbf->invec[2];
                                if (nf > FTINY) {       /* rotate to match */
                                        nf = sqrt((1.-invec[2]*invec[2])/nf);
                                        invec[0] = nf*rbf->invec[0];
                                        invec[1] = nf*rbf->invec[1];
                                }
                                return(0);
                        }
                    break;
                }
            }
            return(-1);                         /* outside range! */
        }
        {                                       /* else use triangle mesh */
                int             sym = use_symmetry(invec);
                int             nedges = 0;
                MIGRATION       *mep;
                unsigned char   *emap;
                                                /* clear visitation map */
                for (mep = mig_list; mep != NULL; mep = mep->next)
                        ++nedges;
                emap = (unsigned char *)calloc((nedges*(nedges-1) + 7)>>3, 1);
                if (emap == NULL) {
                        fprintf(stderr, "%s: Out of memory in get_interp()\n",
                                        progname);
                        exit(1);
                }
                                                /* identify intersection  */
                if (!in_mesh(miga, emap, nedges, invec, mig_list)) {
#ifdef DEBUG
                        fprintf(stderr,
                        "Incident angle (%.1f,%.1f) deg. outside mesh\n",
                                        get_theta180(invec), get_phi360(invec));
#endif
                        sym = -1;               /* outside mesh */
                } else if (miga[1] != NULL &&
                                (miga[2] == NULL || !order_triangle(miga))) {
#ifdef DEBUG
                        fputs("Munged triangle in get_interp()\n", stderr);
#endif
                        sym = -1;
                }
                free(emap);
                return(sym);                    /* return in standard order */
        }
}

/* Advect and allocate new RBF along edge */
static RBFNODE *
e_advect_rbf(const MIGRATION *mig, const FVECT invec, int lobe_lim)
{
        double          cthresh = FTINY;
        RBFNODE         *rbf;
        int             n, i, j;
        double          t, full_dist;
                                                /* get relative position */
        t = Acos(DOT(invec, mig->rbfv[0]->invec));
        if (t < M_PI/grid_res) {                /* near first DSF */
                n = sizeof(RBFNODE) + sizeof(RBFVAL)*(mig->rbfv[0]->nrbf-1);
                rbf = (RBFNODE *)malloc(n);
                if (rbf == NULL)
                        goto memerr;
                memcpy(rbf, mig->rbfv[0], n);   /* just duplicate */
                rbf->next = NULL; rbf->ejl = NULL;
                return(rbf);
        }
        full_dist = acos(DOT(mig->rbfv[0]->invec, mig->rbfv[1]->invec));
        if (t > full_dist-M_PI/grid_res) {      /* near second DSF */
                n = sizeof(RBFNODE) + sizeof(RBFVAL)*(mig->rbfv[1]->nrbf-1);
                rbf = (RBFNODE *)malloc(n);
                if (rbf == NULL)
                        goto memerr;
                memcpy(rbf, mig->rbfv[1], n);   /* just duplicate */
                rbf->next = NULL; rbf->ejl = NULL;
                return(rbf);
        }
        t /= full_dist;
tryagain:
        n = 0;                                  /* count migrating particles */
        for (i = 0; i < mtx_nrows(mig); i++)
            for (j = 0; j < mtx_ncols(mig); j++)
                n += (mtx_coef(mig,i,j) > cthresh);
                                                /* are we over our limit? */
        if ((lobe_lim > 0) & (n > lobe_lim)) {
                cthresh = cthresh*2. + 10.*FTINY;
                goto tryagain;
        }
#ifdef DEBUG
        fprintf(stderr, "Input RBFs have %d, %d nodes -> output has %d\n",
                        mig->rbfv[0]->nrbf, mig->rbfv[1]->nrbf, n);
#endif
        rbf = (RBFNODE *)malloc(sizeof(RBFNODE) + sizeof(RBFVAL)*(n-1));
        if (rbf == NULL)
                goto memerr;
        rbf->next = NULL; rbf->ejl = NULL;
        VCOPY(rbf->invec, invec);
        rbf->nrbf = n;
        rbf->vtotal = 1.-t + t*mig->rbfv[1]->vtotal/mig->rbfv[0]->vtotal;
        n = 0;                                  /* advect RBF lobes */
        for (i = 0; i < mtx_nrows(mig); i++) {
            const RBFVAL        *rbf0i = &mig->rbfv[0]->rbfa[i];
            const float         peak0 = rbf0i->peak;
            const double        rad0 = R2ANG(rbf0i->crad);
            FVECT               v0;
            float               mv;
            ovec_from_pos(v0, rbf0i->gx, rbf0i->gy);
            for (j = 0; j < mtx_ncols(mig); j++)
                if ((mv = mtx_coef(mig,i,j)) > cthresh) {
                        const RBFVAL    *rbf1j = &mig->rbfv[1]->rbfa[j];
                        double          rad2;
                        FVECT           v;
                        int             pos[2];
                        rad2 = R2ANG(rbf1j->crad);
                        rad2 = rad0*rad0*(1.-t) + rad2*rad2*t;
                        rbf->rbfa[n].peak = peak0 * mv * rbf->vtotal *
                                                rad0*rad0/rad2;
                        rbf->rbfa[n].crad = ANG2R(sqrt(rad2));
                        ovec_from_pos(v, rbf1j->gx, rbf1j->gy);
                        geodesic(v, v0, v, t, GEOD_REL);
                        pos_from_vec(pos, v);
                        rbf->rbfa[n].gx = pos[0];
                        rbf->rbfa[n].gy = pos[1];
                        ++n;
                }
        }
        rbf->vtotal *= mig->rbfv[0]->vtotal;    /* turn ratio into actual */
        return(rbf);
memerr:
        fprintf(stderr, "%s: Out of memory in e_advect_rbf()\n", progname);
        exit(1);
        return(NULL);   /* pro forma return */
}

/* Advect between recorded incident angles and allocate new RBF */
RBFNODE *
advect_rbf(const FVECT invec, int lobe_lim)
{
        double          cthresh = FTINY;
        FVECT           sivec;
        MIGRATION       *miga[3];
        RBFNODE         *rbf;
        int             sym;
        float           mbfact, mcfact;
        int             n, i, j, k;
        FVECT           v0, v1, v2;
        double          s, t;

        VCOPY(sivec, invec);                    /* find triangle/edge */
        sym = get_interp(miga, sivec);
        if (sym < 0)                            /* can't interpolate? */
                return(NULL);
        if (miga[1] == NULL) {                  /* advect along edge? */
                rbf = e_advect_rbf(miga[0], sivec, lobe_lim);
                if (single_plane_incident)
                        rotate_rbf(rbf, invec);
                else
                        rev_rbf_symmetry(rbf, sym);
                return(rbf);
        }
#ifdef DEBUG
        if ((miga[0]->rbfv[0] != miga[2]->rbfv[0]) |
                        (miga[0]->rbfv[1] != miga[1]->rbfv[0]) |
                        (miga[1]->rbfv[1] != miga[2]->rbfv[1])) {
                fprintf(stderr, "%s: Triangle vertex screw-up!\n", progname);
                exit(1);
        }
#endif
                                                /* figure out position */
        fcross(v0, miga[2]->rbfv[0]->invec, miga[2]->rbfv[1]->invec);
        normalize(v0);
        fcross(v2, miga[1]->rbfv[0]->invec, miga[1]->rbfv[1]->invec);
        normalize(v2);
        fcross(v1, sivec, miga[1]->rbfv[1]->invec);
        normalize(v1);
        s = acos(DOT(v0,v1)) / acos(DOT(v0,v2));
        geodesic(v1, miga[0]->rbfv[0]->invec, miga[0]->rbfv[1]->invec,
                        s, GEOD_REL);
        t = acos(DOT(v1,sivec)) / acos(DOT(v1,miga[1]->rbfv[1]->invec));
tryagain:
        n = 0;                                  /* count migrating particles */
        for (i = 0; i < mtx_nrows(miga[0]); i++)
            for (j = 0; j < mtx_ncols(miga[0]); j++)
                for (k = (mtx_coef(miga[0],i,j) > cthresh) *
                                        mtx_ncols(miga[2]); k--; )
                        n += (mtx_coef(miga[2],i,k) > cthresh ||
                                mtx_coef(miga[1],j,k) > cthresh);
                                                /* are we over our limit? */
        if ((lobe_lim > 0) & (n > lobe_lim)) {
                cthresh = cthresh*2. + 10.*FTINY;
                goto tryagain;
        }
#ifdef DEBUG
        fprintf(stderr, "Input RBFs have %d, %d, %d nodes -> output has %d\n",
                        miga[0]->rbfv[0]->nrbf, miga[0]->rbfv[1]->nrbf,
                        miga[2]->rbfv[1]->nrbf, n);
#endif
        rbf = (RBFNODE *)malloc(sizeof(RBFNODE) + sizeof(RBFVAL)*(n-1));
        if (rbf == NULL) {
                fprintf(stderr, "%s: Out of memory in advect_rbf()\n", progname);
                exit(1);
        }
        rbf->next = NULL; rbf->ejl = NULL;
        VCOPY(rbf->invec, sivec);
        rbf->nrbf = n;
        n = 0;                                  /* compute RBF lobes */
        mbfact = s * miga[0]->rbfv[1]->vtotal/miga[0]->rbfv[0]->vtotal *
                (1.-t + t*miga[1]->rbfv[1]->vtotal/miga[1]->rbfv[0]->vtotal);
        mcfact = (1.-s) *
                (1.-t + t*miga[2]->rbfv[1]->vtotal/miga[2]->rbfv[0]->vtotal);
        for (i = 0; i < mtx_nrows(miga[0]); i++) {
            const RBFVAL        *rbf0i = &miga[0]->rbfv[0]->rbfa[i];
            const float         w0i = rbf0i->peak;
            const double        rad0i = R2ANG(rbf0i->crad);
            ovec_from_pos(v0, rbf0i->gx, rbf0i->gy);
            for (j = 0; j < mtx_ncols(miga[0]); j++) {
                const float     ma = mtx_coef(miga[0],i,j);
                const RBFVAL    *rbf1j;
                double          srad2;
                if (ma <= cthresh)
                        continue;
                rbf1j = &miga[0]->rbfv[1]->rbfa[j];
                srad2 = R2ANG(rbf1j->crad);
                srad2 = (1.-s)*(1.-t)*rad0i*rad0i + s*(1.-t)*srad2*srad2;
                ovec_from_pos(v1, rbf1j->gx, rbf1j->gy);
                geodesic(v1, v0, v1, s, GEOD_REL);
                for (k = 0; k < mtx_ncols(miga[2]); k++) {
                    float               mb = mtx_coef(miga[1],j,k);
                    float               mc = mtx_coef(miga[2],i,k);
                    const RBFVAL        *rbf2k;
                    double              rad2;
                    int                 pos[2];
                    if ((mb <= cthresh) & (mc <= cthresh))
                        continue;
                    rbf2k = &miga[2]->rbfv[1]->rbfa[k];
                    rad2 = R2ANG(rbf2k->crad);
                    rad2 = srad2 + t*rad2*rad2;
                    rbf->rbfa[n].peak = w0i * ma * (mb*mbfact + mc*mcfact) *
                                        rad0i*rad0i/rad2;
                    rbf->rbfa[n].crad = ANG2R(sqrt(rad2));
                    ovec_from_pos(v2, rbf2k->gx, rbf2k->gy);
                    geodesic(v2, v1, v2, t, GEOD_REL);
                    pos_from_vec(pos, v2);
                    rbf->rbfa[n].gx = pos[0];
                    rbf->rbfa[n].gy = pos[1];
                    ++n;
                }
            }
        }
        rbf->vtotal = miga[0]->rbfv[0]->vtotal * (mbfact + mcfact);
        rev_rbf_symmetry(rbf, sym);
        return(rbf);
}
Revision:	2.16
Committed:	Tue Feb 18 16:06:51 2014 UTC (11 years, 8 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.15:	+7 -7 lines
Log Message:	Added normal incidence interpolation for quadrilateral and radial symmetry
#	User	Rev	Content
1	greg	2.1	#ifndef lint
2	greg	2.16	static const char RCSid[] = "$Id: bsdfinterp.c,v 2.15 2013/10/23 03:41:39 greg Exp $";
3	greg	2.1	#endif
4			/*
5			* Interpolate BSDF data from radial basis functions in advection mesh.
6			*
7			* G. Ward
8			*/
9
10			#define _USE_MATH_DEFINES
11			#include <stdio.h>
12			#include <stdlib.h>
13			#include <string.h>
14			#include <math.h>
15			#include "bsdfrep.h"
16
17			/* Insert vertex in ordered list */
18			static void
19			insert_vert(RBFNODE *vlist, RBFNODE v)
20			{
21			int i, j;
22
23			for (i = 0; vlist[i] != NULL; i++) {
24			if (v == vlist[i])
25			return;
26			if (v->ord < vlist[i]->ord)
27			break;
28			}
29			for (j = i; vlist[j] != NULL; j++)
30			;
31			while (j > i) {
32			vlist[j] = vlist[j-1];
33			--j;
34			}
35			vlist[i] = v;
36			}
37
38			/* Sort triangle edges in standard order */
39			static int
40			order_triangle(MIGRATION *miga[3])
41			{
42			RBFNODE *vert[7];
43			MIGRATION *ord[3];
44			int i;
45			/* order vertices, first */
46			memset(vert, 0, sizeof(vert));
47			for (i = 3; i--; ) {
48			if (miga[i] == NULL)
49			return(0);
50			insert_vert(vert, miga[i]->rbfv[0]);
51			insert_vert(vert, miga[i]->rbfv[1]);
52			}
53			/* should be just 3 vertices */
54	greg	2.4	if ((vert[2] == NULL) \| (vert[3] != NULL))
55	greg	2.1	return(0);
56			/* identify edge 0 */
57			for (i = 3; i--; )
58			if (miga[i]->rbfv[0] == vert[0] &&
59			miga[i]->rbfv[1] == vert[1]) {
60			ord[0] = miga[i];
61			break;
62			}
63			if (i < 0)
64			return(0);
65			/* identify edge 1 */
66			for (i = 3; i--; )
67			if (miga[i]->rbfv[0] == vert[1] &&
68			miga[i]->rbfv[1] == vert[2]) {
69			ord[1] = miga[i];
70			break;
71			}
72			if (i < 0)
73			return(0);
74			/* identify edge 2 */
75			for (i = 3; i--; )
76			if (miga[i]->rbfv[0] == vert[0] &&
77			miga[i]->rbfv[1] == vert[2]) {
78			ord[2] = miga[i];
79			break;
80			}
81			if (i < 0)
82			return(0);
83			/* reassign order */
84			miga[0] = ord[0]; miga[1] = ord[1]; miga[2] = ord[2];
85			return(1);
86			}
87
88	greg	2.4	/* Determine if we are close enough to an edge */
89	greg	2.3	static int
90			on_edge(const MIGRATION *ej, const FVECT ivec)
91			{
92	greg	2.4	double cos_a, cos_b, cos_c, cos_aplusb;
93			/* use triangle inequality */
94			cos_a = DOT(ej->rbfv[0]->invec, ivec);
95			if (cos_a <= 0)
96			return(0);
97	greg	2.15	if (cos_a >= 1.) /* handles rounding error */
98			return(1);
99	greg	2.4
100			cos_b = DOT(ej->rbfv[1]->invec, ivec);
101			if (cos_b <= 0)
102			return(0);
103	greg	2.15	if (cos_b >= 1.)
104			return(1);
105	greg	2.3
106	greg	2.4	cos_aplusb = cos_acos_b - sqrt((1.-cos_acos_a)(1.-cos_bcos_b));
107			if (cos_aplusb <= 0)
108			return(0);
109
110			cos_c = DOT(ej->rbfv[0]->invec, ej->rbfv[1]->invec);
111
112			return(cos_c - cos_aplusb < .001);
113	greg	2.3	}
114
115			/* Determine if we are inside the given triangle */
116			static int
117			in_tri(const RBFNODE v1, const RBFNODE v2, const RBFNODE *v3, const FVECT p)
118			{
119			FVECT vc;
120			int sgn1, sgn2, sgn3;
121			/* signed volume test */
122			VCROSS(vc, v1->invec, v2->invec);
123			sgn1 = (DOT(p, vc) > 0);
124			VCROSS(vc, v2->invec, v3->invec);
125			sgn2 = (DOT(p, vc) > 0);
126			if (sgn1 != sgn2)
127			return(0);
128			VCROSS(vc, v3->invec, v1->invec);
129			sgn3 = (DOT(p, vc) > 0);
130			return(sgn2 == sgn3);
131			}
132
133	greg	2.6	/* Test (and set) bitmap for edge */
134	greg	2.4	static int
135			check_edge(unsigned char emap, int nedges, const MIGRATION mig, int mark)
136			{
137			int ejndx, bit2check;
138
139			if (mig->rbfv[0]->ord > mig->rbfv[1]->ord)
140			ejndx = mig->rbfv[1]->ord + (nedges-1)*mig->rbfv[0]->ord;
141			else
142			ejndx = mig->rbfv[0]->ord + (nedges-1)*mig->rbfv[1]->ord;
143
144			bit2check = 1<<(ejndx&07);
145
146			if (emap[ejndx>>3] & bit2check)
147			return(0);
148			if (mark)
149			emap[ejndx>>3] \|= bit2check;
150			return(1);
151			}
152
153	greg	2.3	/* Compute intersection with the given position over remaining mesh */
154			static int
155			in_mesh(MIGRATION miga[3], unsigned char emap, int nedges,
156			const FVECT ivec, MIGRATION *mig)
157			{
158	greg	2.9	RBFNODE *tv[2];
159			MIGRATION sej[2], dej[2];
160			int i;
161	greg	2.3	/* check visitation record */
162	greg	2.4	if (!check_edge(emap, nedges, mig, 1))
163	greg	2.3	return(0);
164			if (on_edge(mig, ivec)) {
165			miga[0] = mig; /* close enough to edge */
166			return(1);
167			}
168	greg	2.9	if (!get_triangles(tv, mig)) /* do triangles either side? */
169			return(0);
170			for (i = 2; i--; ) { /* identify edges to check */
171			MIGRATION *ej;
172			sej[i] = dej[i] = NULL;
173			if (tv[i] == NULL)
174			continue;
175			for (ej = tv[i]->ejl; ej != NULL; ej = nextedge(tv[i],ej)) {
176			RBFNODE *rbfop = opp_rbf(tv[i],ej);
177			if (rbfop == mig->rbfv[0]) {
178			if (check_edge(emap, nedges, ej, 0))
179			sej[i] = ej;
180			} else if (rbfop == mig->rbfv[1]) {
181			if (check_edge(emap, nedges, ej, 0))
182			dej[i] = ej;
183	greg	2.3	}
184	greg	2.4	}
185	greg	2.3	}
186	greg	2.9	for (i = 2; i--; ) { /* check triangles just once */
187			if (sej[i] != NULL && in_mesh(miga, emap, nedges, ivec, sej[i]))
188			return(1);
189			if (dej[i] != NULL && in_mesh(miga, emap, nedges, ivec, dej[i]))
190			return(1);
191			if ((sej[i] == NULL) \| (dej[i] == NULL))
192			continue;
193			if (in_tri(mig->rbfv[0], mig->rbfv[1], tv[i], ivec)) {
194			miga[0] = mig;
195			miga[1] = sej[i];
196			miga[2] = dej[i];
197			return(1);
198			}
199			}
200	greg	2.4	return(0); /* not near this edge */
201	greg	2.3	}
202
203	greg	2.1	/* Find edge(s) for interpolating the given vector, applying symmetry */
204			int
205			get_interp(MIGRATION *miga[3], FVECT invec)
206			{
207			miga[0] = miga[1] = miga[2] = NULL;
208			if (single_plane_incident) { /* isotropic BSDF? */
209	greg	2.10	RBFNODE rbf; / find edge we're on */
210			for (rbf = dsf_list; rbf != NULL; rbf = rbf->next) {
211	greg	2.16	if (input_orientrbf->invec[2] < input_orientinvec[2]-FTINY)
212	greg	2.10	break;
213			if (rbf->next != NULL && input_orient*rbf->next->invec[2] <
214	greg	2.16	input_orient*invec[2]+FTINY) {
215	greg	2.10	for (miga[0] = rbf->ejl; miga[0] != NULL;
216			miga[0] = nextedge(rbf,miga[0]))
217			if (opp_rbf(rbf,miga[0]) == rbf->next) {
218			double nf = 1. - rbf->invec[2]*rbf->invec[2];
219			if (nf > FTINY) { /* rotate to match */
220			nf = sqrt((1.-invec[2]*invec[2])/nf);
221			invec[0] = nf*rbf->invec[0];
222			invec[1] = nf*rbf->invec[1];
223			}
224			return(0);
225	greg	2.1	}
226	greg	2.10	break;
227	greg	2.1	}
228	greg	2.10	}
229			return(-1); /* outside range! */
230	greg	2.1	}
231			{ /* else use triangle mesh */
232	greg	2.3	int sym = use_symmetry(invec);
233			int nedges = 0;
234			MIGRATION *mep;
235			unsigned char *emap;
236			/* clear visitation map */
237			for (mep = mig_list; mep != NULL; mep = mep->next)
238			++nedges;
239			emap = (unsigned char )calloc((nedges(nedges-1) + 7)>>3, 1);
240			if (emap == NULL) {
241			fprintf(stderr, "%s: Out of memory in get_interp()\n",
242			progname);
243			exit(1);
244			}
245			/* identify intersection */
246	greg	2.9	if (!in_mesh(miga, emap, nedges, invec, mig_list)) {
247			#ifdef DEBUG
248			fprintf(stderr,
249			"Incident angle (%.1f,%.1f) deg. outside mesh\n",
250			get_theta180(invec), get_phi360(invec));
251			#endif
252	greg	2.3	sym = -1; /* outside mesh */
253	greg	2.9	} else if (miga[1] != NULL &&
254	greg	2.3	(miga[2] == NULL \|\| !order_triangle(miga))) {
255	greg	2.1	#ifdef DEBUG
256			fputs("Munged triangle in get_interp()\n", stderr);
257			#endif
258	greg	2.3	sym = -1;
259	greg	2.1	}
260	greg	2.3	free(emap);
261	greg	2.1	return(sym); /* return in standard order */
262			}
263			}
264
265			/* Advect and allocate new RBF along edge */
266			static RBFNODE *
267	greg	2.13	e_advect_rbf(const MIGRATION *mig, const FVECT invec, int lobe_lim)
268	greg	2.1	{
269	greg	2.13	double cthresh = FTINY;
270	greg	2.1	RBFNODE *rbf;
271			int n, i, j;
272			double t, full_dist;
273			/* get relative position */
274	greg	2.11	t = Acos(DOT(invec, mig->rbfv[0]->invec));
275	greg	2.5	if (t < M_PI/grid_res) { /* near first DSF */
276	greg	2.1	n = sizeof(RBFNODE) + sizeof(RBFVAL)*(mig->rbfv[0]->nrbf-1);
277			rbf = (RBFNODE *)malloc(n);
278			if (rbf == NULL)
279			goto memerr;
280			memcpy(rbf, mig->rbfv[0], n); /* just duplicate */
281	greg	2.8	rbf->next = NULL; rbf->ejl = NULL;
282	greg	2.1	return(rbf);
283			}
284			full_dist = acos(DOT(mig->rbfv[0]->invec, mig->rbfv[1]->invec));
285	greg	2.5	if (t > full_dist-M_PI/grid_res) { /* near second DSF */
286	greg	2.1	n = sizeof(RBFNODE) + sizeof(RBFVAL)*(mig->rbfv[1]->nrbf-1);
287			rbf = (RBFNODE *)malloc(n);
288			if (rbf == NULL)
289			goto memerr;
290			memcpy(rbf, mig->rbfv[1], n); /* just duplicate */
291	greg	2.8	rbf->next = NULL; rbf->ejl = NULL;
292	greg	2.1	return(rbf);
293			}
294	greg	2.13	t /= full_dist;
295			tryagain:
296	greg	2.1	n = 0; /* count migrating particles */
297			for (i = 0; i < mtx_nrows(mig); i++)
298			for (j = 0; j < mtx_ncols(mig); j++)
299	greg	2.13	n += (mtx_coef(mig,i,j) > cthresh);
300			/* are we over our limit? */
301			if ((lobe_lim > 0) & (n > lobe_lim)) {
302			cthresh = cthresh2. + 10.FTINY;
303			goto tryagain;
304			}
305	greg	2.1	#ifdef DEBUG
306			fprintf(stderr, "Input RBFs have %d, %d nodes -> output has %d\n",
307			mig->rbfv[0]->nrbf, mig->rbfv[1]->nrbf, n);
308			#endif
309			rbf = (RBFNODE )malloc(sizeof(RBFNODE) + sizeof(RBFVAL)(n-1));
310			if (rbf == NULL)
311			goto memerr;
312			rbf->next = NULL; rbf->ejl = NULL;
313			VCOPY(rbf->invec, invec);
314			rbf->nrbf = n;
315			rbf->vtotal = 1.-t + t*mig->rbfv[1]->vtotal/mig->rbfv[0]->vtotal;
316			n = 0; /* advect RBF lobes */
317			for (i = 0; i < mtx_nrows(mig); i++) {
318			const RBFVAL *rbf0i = &mig->rbfv[0]->rbfa[i];
319			const float peak0 = rbf0i->peak;
320			const double rad0 = R2ANG(rbf0i->crad);
321			FVECT v0;
322			float mv;
323			ovec_from_pos(v0, rbf0i->gx, rbf0i->gy);
324			for (j = 0; j < mtx_ncols(mig); j++)
325	greg	2.13	if ((mv = mtx_coef(mig,i,j)) > cthresh) {
326	greg	2.1	const RBFVAL *rbf1j = &mig->rbfv[1]->rbfa[j];
327	greg	2.14	double rad2;
328	greg	2.1	FVECT v;
329			int pos[2];
330	greg	2.14	rad2 = R2ANG(rbf1j->crad);
331			rad2 = rad0rad0(1.-t) + rad2rad2t;
332			rbf->rbfa[n].peak = peak0 * mv * rbf->vtotal *
333			rad0*rad0/rad2;
334			rbf->rbfa[n].crad = ANG2R(sqrt(rad2));
335	greg	2.1	ovec_from_pos(v, rbf1j->gx, rbf1j->gy);
336	greg	2.8	geodesic(v, v0, v, t, GEOD_REL);
337	greg	2.1	pos_from_vec(pos, v);
338			rbf->rbfa[n].gx = pos[0];
339			rbf->rbfa[n].gy = pos[1];
340			++n;
341			}
342			}
343			rbf->vtotal = mig->rbfv[0]->vtotal; / turn ratio into actual */
344			return(rbf);
345			memerr:
346			fprintf(stderr, "%s: Out of memory in e_advect_rbf()\n", progname);
347			exit(1);
348			return(NULL); /* pro forma return */
349			}
350
351	greg	2.16	/* Advect between recorded incident angles and allocate new RBF */
352	greg	2.1	RBFNODE *
353	greg	2.12	advect_rbf(const FVECT invec, int lobe_lim)
354	greg	2.1	{
355	greg	2.12	double cthresh = FTINY;
356	greg	2.1	FVECT sivec;
357			MIGRATION *miga[3];
358			RBFNODE *rbf;
359			int sym;
360			float mbfact, mcfact;
361			int n, i, j, k;
362			FVECT v0, v1, v2;
363	greg	2.8	double s, t;
364	greg	2.1
365			VCOPY(sivec, invec); /* find triangle/edge */
366			sym = get_interp(miga, sivec);
367			if (sym < 0) /* can't interpolate? */
368			return(NULL);
369			if (miga[1] == NULL) { /* advect along edge? */
370	greg	2.13	rbf = e_advect_rbf(miga[0], sivec, lobe_lim);
371	greg	2.5	if (single_plane_incident)
372			rotate_rbf(rbf, invec);
373			else
374			rev_rbf_symmetry(rbf, sym);
375	greg	2.1	return(rbf);
376			}
377			#ifdef DEBUG
378	greg	2.16	if ((miga[0]->rbfv[0] != miga[2]->rbfv[0]) \|
379			(miga[0]->rbfv[1] != miga[1]->rbfv[0]) \|
380			(miga[1]->rbfv[1] != miga[2]->rbfv[1])) {
381	greg	2.1	fprintf(stderr, "%s: Triangle vertex screw-up!\n", progname);
382			exit(1);
383			}
384			#endif
385			/* figure out position */
386			fcross(v0, miga[2]->rbfv[0]->invec, miga[2]->rbfv[1]->invec);
387			normalize(v0);
388			fcross(v2, miga[1]->rbfv[0]->invec, miga[1]->rbfv[1]->invec);
389			normalize(v2);
390			fcross(v1, sivec, miga[1]->rbfv[1]->invec);
391			normalize(v1);
392	greg	2.7	s = acos(DOT(v0,v1)) / acos(DOT(v0,v2));
393	greg	2.1	geodesic(v1, miga[0]->rbfv[0]->invec, miga[0]->rbfv[1]->invec,
394	greg	2.7	s, GEOD_REL);
395	greg	2.8	t = acos(DOT(v1,sivec)) / acos(DOT(v1,miga[1]->rbfv[1]->invec));
396	greg	2.12	tryagain:
397	greg	2.1	n = 0; /* count migrating particles */
398			for (i = 0; i < mtx_nrows(miga[0]); i++)
399			for (j = 0; j < mtx_ncols(miga[0]); j++)
400	greg	2.12	for (k = (mtx_coef(miga[0],i,j) > cthresh) *
401	greg	2.1	mtx_ncols(miga[2]); k--; )
402	greg	2.12	n += (mtx_coef(miga[2],i,k) > cthresh \|\|
403			mtx_coef(miga[1],j,k) > cthresh);
404	greg	2.13	/* are we over our limit? */
405	greg	2.12	if ((lobe_lim > 0) & (n > lobe_lim)) {
406			cthresh = cthresh2. + 10.FTINY;
407			goto tryagain;
408			}
409	greg	2.1	#ifdef DEBUG
410			fprintf(stderr, "Input RBFs have %d, %d, %d nodes -> output has %d\n",
411			miga[0]->rbfv[0]->nrbf, miga[0]->rbfv[1]->nrbf,
412			miga[2]->rbfv[1]->nrbf, n);
413			#endif
414			rbf = (RBFNODE )malloc(sizeof(RBFNODE) + sizeof(RBFVAL)(n-1));
415			if (rbf == NULL) {
416			fprintf(stderr, "%s: Out of memory in advect_rbf()\n", progname);
417			exit(1);
418			}
419			rbf->next = NULL; rbf->ejl = NULL;
420			VCOPY(rbf->invec, sivec);
421			rbf->nrbf = n;
422			n = 0; /* compute RBF lobes */
423			mbfact = s * miga[0]->rbfv[1]->vtotal/miga[0]->rbfv[0]->vtotal *
424			(1.-t + t*miga[1]->rbfv[1]->vtotal/miga[1]->rbfv[0]->vtotal);
425			mcfact = (1.-s) *
426			(1.-t + t*miga[2]->rbfv[1]->vtotal/miga[2]->rbfv[0]->vtotal);
427			for (i = 0; i < mtx_nrows(miga[0]); i++) {
428			const RBFVAL *rbf0i = &miga[0]->rbfv[0]->rbfa[i];
429			const float w0i = rbf0i->peak;
430			const double rad0i = R2ANG(rbf0i->crad);
431			ovec_from_pos(v0, rbf0i->gx, rbf0i->gy);
432			for (j = 0; j < mtx_ncols(miga[0]); j++) {
433	greg	2.2	const float ma = mtx_coef(miga[0],i,j);
434	greg	2.1	const RBFVAL *rbf1j;
435	greg	2.14	double srad2;
436	greg	2.12	if (ma <= cthresh)
437	greg	2.1	continue;
438			rbf1j = &miga[0]->rbfv[1]->rbfa[j];
439	greg	2.14	srad2 = R2ANG(rbf1j->crad);
440			srad2 = (1.-s)(1.-t)rad0irad0i + s(1.-t)srad2srad2;
441	greg	2.1	ovec_from_pos(v1, rbf1j->gx, rbf1j->gy);
442	greg	2.7	geodesic(v1, v0, v1, s, GEOD_REL);
443	greg	2.1	for (k = 0; k < mtx_ncols(miga[2]); k++) {
444	greg	2.2	float mb = mtx_coef(miga[1],j,k);
445			float mc = mtx_coef(miga[2],i,k);
446	greg	2.1	const RBFVAL *rbf2k;
447	greg	2.14	double rad2;
448	greg	2.1	int pos[2];
449	greg	2.12	if ((mb <= cthresh) & (mc <= cthresh))
450	greg	2.1	continue;
451			rbf2k = &miga[2]->rbfv[1]->rbfa[k];
452	greg	2.14	rad2 = R2ANG(rbf2k->crad);
453			rad2 = srad2 + trad2rad2;
454			rbf->rbfa[n].peak = w0i * ma * (mbmbfact + mcmcfact) *
455			rad0i*rad0i/rad2;
456			rbf->rbfa[n].crad = ANG2R(sqrt(rad2));
457	greg	2.1	ovec_from_pos(v2, rbf2k->gx, rbf2k->gy);
458	greg	2.8	geodesic(v2, v1, v2, t, GEOD_REL);
459			pos_from_vec(pos, v2);
460	greg	2.1	rbf->rbfa[n].gx = pos[0];
461			rbf->rbfa[n].gy = pos[1];
462			++n;
463			}
464			}
465			}
466			rbf->vtotal = miga[0]->rbfv[0]->vtotal * (mbfact + mcfact);
467			rev_rbf_symmetry(rbf, sym);
468			return(rbf);
469			}