src/cv/bsdfinterp.c

#ifndef lint
static const char RCSid[] = "$Id: bsdfinterp.c,v 2.7 2012/11/26 07:02:20 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);

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

        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)
{
        MIGRATION       *ej1, *ej2;
        RBFNODE         *tv;
                                                /* 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);
        }
                                                /* do triangles either side */
        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]) {
                        int     do_ej1 = check_edge(emap, nedges, ej1, 0);
                        int     do_ej2 = check_edge(emap, nedges, ej2, 0);
                        if (do_ej1 && in_mesh(miga, emap, nedges, ivec, ej1))
                                return(1);
                        if (do_ej2 && in_mesh(miga, emap, nedges, ivec, ej2))
                                return(1);
                                                /* check just once */
                        if (do_ej1 & do_ej2 && in_tri(mig->rbfv[0],
                                                mig->rbfv[1], tv, ivec)) {
                                miga[0] = mig;
                                miga[1] = ej1;
                                miga[2] = ej2;
                                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])
                                break;
                        if (rbf->next != NULL &&
                                        input_orient*rbf->next->invec[2] <
                                                        input_orient*invec[2]) {
                                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) {
                                                        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))
                        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)
{
        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; 
        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) > FTINY);
#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)) > FTINY) {
                        const RBFVAL    *rbf1j = &mig->rbfv[1]->rbfa[j];
                        double          rad1 = R2ANG(rbf1j->crad);
                        FVECT           v;
                        int             pos[2];
                        rbf->rbfa[n].peak = peak0 * mv * rbf->vtotal;
                        rbf->rbfa[n].crad = ANG2R(sqrt(rad0*rad0*(1.-t) +
                                                        rad1*rad1*t));
                        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 */
}

/* Partially advect between recorded incident angles and allocate new RBF */
RBFNODE *
advect_rbf(const FVECT invec)
{
        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);
                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));
        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) > FTINY) *
                                        mtx_ncols(miga[2]); k--; )
                        n += (mtx_coef(miga[2],i,k) > FTINY ||
                                mtx_coef(miga[1],j,k) > FTINY);
#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          rad1j, srad2;
                if (ma <= FTINY)
                        continue;
                rbf1j = &miga[0]->rbfv[1]->rbfa[j];
                rad1j = R2ANG(rbf1j->crad);
                srad2 = (1.-s)*(1.-t)*rad0i*rad0i + s*(1.-t)*rad1j*rad1j;
                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              rad2k;
                    int                 pos[2];
                    if ((mb <= FTINY) & (mc <= FTINY))
                        continue;
                    rbf2k = &miga[2]->rbfv[1]->rbfa[k];
                    rbf->rbfa[n].peak = w0i * ma * (mb*mbfact + mc*mcfact);
                    rad2k = R2ANG(rbf2k->crad);
                    rbf->rbfa[n].crad = ANG2R(sqrt(srad2 + t*rad2k*rad2k));
                    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:	2.8
Committed:	Wed Dec 12 04:49:59 2012 UTC (12 years, 10 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.7:	+8 -8 lines
Log Message:	Fixed main bug, which was forgetting Klems axis reversal
#	User	Rev	Content
1	greg	2.1	#ifndef lint
2	greg	2.8	static const char RCSid[] = "$Id: bsdfinterp.c,v 2.7 2012/11/26 07:02:20 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
98			cos_b = DOT(ej->rbfv[1]->invec, ivec);
99			if (cos_b <= 0)
100			return(0);
101	greg	2.3
102	greg	2.4	cos_aplusb = cos_acos_b - sqrt((1.-cos_acos_a)(1.-cos_bcos_b));
103			if (cos_aplusb <= 0)
104			return(0);
105
106			cos_c = DOT(ej->rbfv[0]->invec, ej->rbfv[1]->invec);
107
108			return(cos_c - cos_aplusb < .001);
109	greg	2.3	}
110
111			/* Determine if we are inside the given triangle */
112			static int
113			in_tri(const RBFNODE v1, const RBFNODE v2, const RBFNODE *v3, const FVECT p)
114			{
115			FVECT vc;
116			int sgn1, sgn2, sgn3;
117			/* signed volume test */
118			VCROSS(vc, v1->invec, v2->invec);
119			sgn1 = (DOT(p, vc) > 0);
120			VCROSS(vc, v2->invec, v3->invec);
121			sgn2 = (DOT(p, vc) > 0);
122			if (sgn1 != sgn2)
123			return(0);
124			VCROSS(vc, v3->invec, v1->invec);
125			sgn3 = (DOT(p, vc) > 0);
126			return(sgn2 == sgn3);
127			}
128
129	greg	2.6	/* Test (and set) bitmap for edge */
130	greg	2.4	static int
131			check_edge(unsigned char emap, int nedges, const MIGRATION mig, int mark)
132			{
133			int ejndx, bit2check;
134
135			if (mig->rbfv[0]->ord > mig->rbfv[1]->ord)
136			ejndx = mig->rbfv[1]->ord + (nedges-1)*mig->rbfv[0]->ord;
137			else
138			ejndx = mig->rbfv[0]->ord + (nedges-1)*mig->rbfv[1]->ord;
139
140			bit2check = 1<<(ejndx&07);
141
142			if (emap[ejndx>>3] & bit2check)
143			return(0);
144			if (mark)
145			emap[ejndx>>3] \|= bit2check;
146			return(1);
147			}
148
149	greg	2.3	/* Compute intersection with the given position over remaining mesh */
150			static int
151			in_mesh(MIGRATION miga[3], unsigned char emap, int nedges,
152			const FVECT ivec, MIGRATION *mig)
153			{
154			MIGRATION ej1, ej2;
155			RBFNODE *tv;
156			/* check visitation record */
157	greg	2.4	if (!check_edge(emap, nedges, mig, 1))
158	greg	2.3	return(0);
159			if (on_edge(mig, ivec)) {
160			miga[0] = mig; /* close enough to edge */
161			return(1);
162			}
163			/* do triangles either side */
164			for (ej1 = mig->rbfv[0]->ejl; ej1 != NULL;
165			ej1 = nextedge(mig->rbfv[0],ej1)) {
166	greg	2.4	if (ej1 == mig)
167			continue;
168			tv = opp_rbf(mig->rbfv[0],ej1);
169			for (ej2 = tv->ejl; ej2 != NULL; ej2 = nextedge(tv,ej2))
170			if (opp_rbf(tv,ej2) == mig->rbfv[1]) {
171			int do_ej1 = check_edge(emap, nedges, ej1, 0);
172			int do_ej2 = check_edge(emap, nedges, ej2, 0);
173			if (do_ej1 && in_mesh(miga, emap, nedges, ivec, ej1))
174			return(1);
175			if (do_ej2 && in_mesh(miga, emap, nedges, ivec, ej2))
176			return(1);
177			/* check just once */
178			if (do_ej1 & do_ej2 && in_tri(mig->rbfv[0],
179			mig->rbfv[1], tv, ivec)) {
180			miga[0] = mig;
181			miga[1] = ej1;
182			miga[2] = ej2;
183			return(1);
184	greg	2.3	}
185	greg	2.4	}
186	greg	2.3	}
187	greg	2.4	return(0); /* not near this edge */
188	greg	2.3	}
189
190	greg	2.1	/* Find edge(s) for interpolating the given vector, applying symmetry */
191			int
192			get_interp(MIGRATION *miga[3], FVECT invec)
193			{
194			miga[0] = miga[1] = miga[2] = NULL;
195			if (single_plane_incident) { /* isotropic BSDF? */
196			RBFNODE rbf; / find edge we're on */
197			for (rbf = dsf_list; rbf != NULL; rbf = rbf->next) {
198			if (input_orientrbf->invec[2] < input_orientinvec[2])
199			break;
200			if (rbf->next != NULL &&
201			input_orient*rbf->next->invec[2] <
202			input_orient*invec[2]) {
203			for (miga[0] = rbf->ejl; miga[0] != NULL;
204			miga[0] = nextedge(rbf,miga[0]))
205	greg	2.5	if (opp_rbf(rbf,miga[0]) == rbf->next) {
206			double nf = 1.-rbf->invec[2]*rbf->invec[2];
207			if (nf > FTINY) {
208			nf = sqrt((1.-invec[2]*invec[2])/nf);
209			invec[0] = nf*rbf->invec[0];
210			invec[1] = nf*rbf->invec[1];
211			}
212	greg	2.1	return(0);
213	greg	2.5	}
214	greg	2.1	break;
215			}
216			}
217			return(-1); /* outside range! */
218			}
219			{ /* else use triangle mesh */
220	greg	2.3	int sym = use_symmetry(invec);
221			int nedges = 0;
222			MIGRATION *mep;
223			unsigned char *emap;
224			/* clear visitation map */
225			for (mep = mig_list; mep != NULL; mep = mep->next)
226			++nedges;
227			emap = (unsigned char )calloc((nedges(nedges-1) + 7)>>3, 1);
228			if (emap == NULL) {
229			fprintf(stderr, "%s: Out of memory in get_interp()\n",
230			progname);
231			exit(1);
232			}
233			/* identify intersection */
234			if (!in_mesh(miga, emap, nedges, invec, mig_list))
235			sym = -1; /* outside mesh */
236			else if (miga[1] != NULL &&
237			(miga[2] == NULL \|\| !order_triangle(miga))) {
238	greg	2.1	#ifdef DEBUG
239			fputs("Munged triangle in get_interp()\n", stderr);
240			#endif
241	greg	2.3	sym = -1;
242	greg	2.1	}
243	greg	2.3	free(emap);
244	greg	2.1	return(sym); /* return in standard order */
245			}
246			}
247
248			/* Advect and allocate new RBF along edge */
249			static RBFNODE *
250			e_advect_rbf(const MIGRATION *mig, const FVECT invec)
251			{
252			RBFNODE *rbf;
253			int n, i, j;
254			double t, full_dist;
255			/* get relative position */
256			t = acos(DOT(invec, mig->rbfv[0]->invec));
257	greg	2.5	if (t < M_PI/grid_res) { /* near first DSF */
258	greg	2.1	n = sizeof(RBFNODE) + sizeof(RBFVAL)*(mig->rbfv[0]->nrbf-1);
259			rbf = (RBFNODE *)malloc(n);
260			if (rbf == NULL)
261			goto memerr;
262			memcpy(rbf, mig->rbfv[0], n); /* just duplicate */
263	greg	2.8	rbf->next = NULL; rbf->ejl = NULL;
264	greg	2.1	return(rbf);
265			}
266			full_dist = acos(DOT(mig->rbfv[0]->invec, mig->rbfv[1]->invec));
267	greg	2.5	if (t > full_dist-M_PI/grid_res) { /* near second DSF */
268	greg	2.1	n = sizeof(RBFNODE) + sizeof(RBFVAL)*(mig->rbfv[1]->nrbf-1);
269			rbf = (RBFNODE *)malloc(n);
270			if (rbf == NULL)
271			goto memerr;
272			memcpy(rbf, mig->rbfv[1], n); /* just duplicate */
273	greg	2.8	rbf->next = NULL; rbf->ejl = NULL;
274	greg	2.1	return(rbf);
275			}
276			t /= full_dist;
277			n = 0; /* count migrating particles */
278			for (i = 0; i < mtx_nrows(mig); i++)
279			for (j = 0; j < mtx_ncols(mig); j++)
280	greg	2.2	n += (mtx_coef(mig,i,j) > FTINY);
281	greg	2.1	#ifdef DEBUG
282			fprintf(stderr, "Input RBFs have %d, %d nodes -> output has %d\n",
283			mig->rbfv[0]->nrbf, mig->rbfv[1]->nrbf, n);
284			#endif
285			rbf = (RBFNODE )malloc(sizeof(RBFNODE) + sizeof(RBFVAL)(n-1));
286			if (rbf == NULL)
287			goto memerr;
288			rbf->next = NULL; rbf->ejl = NULL;
289			VCOPY(rbf->invec, invec);
290			rbf->nrbf = n;
291			rbf->vtotal = 1.-t + t*mig->rbfv[1]->vtotal/mig->rbfv[0]->vtotal;
292			n = 0; /* advect RBF lobes */
293			for (i = 0; i < mtx_nrows(mig); i++) {
294			const RBFVAL *rbf0i = &mig->rbfv[0]->rbfa[i];
295			const float peak0 = rbf0i->peak;
296			const double rad0 = R2ANG(rbf0i->crad);
297			FVECT v0;
298			float mv;
299			ovec_from_pos(v0, rbf0i->gx, rbf0i->gy);
300			for (j = 0; j < mtx_ncols(mig); j++)
301	greg	2.2	if ((mv = mtx_coef(mig,i,j)) > FTINY) {
302	greg	2.1	const RBFVAL *rbf1j = &mig->rbfv[1]->rbfa[j];
303			double rad1 = R2ANG(rbf1j->crad);
304			FVECT v;
305			int pos[2];
306			rbf->rbfa[n].peak = peak0 * mv * rbf->vtotal;
307			rbf->rbfa[n].crad = ANG2R(sqrt(rad0rad0(1.-t) +
308			rad1rad1t));
309			ovec_from_pos(v, rbf1j->gx, rbf1j->gy);
310	greg	2.8	geodesic(v, v0, v, t, GEOD_REL);
311	greg	2.1	pos_from_vec(pos, v);
312			rbf->rbfa[n].gx = pos[0];
313			rbf->rbfa[n].gy = pos[1];
314			++n;
315			}
316			}
317			rbf->vtotal = mig->rbfv[0]->vtotal; / turn ratio into actual */
318			return(rbf);
319			memerr:
320			fprintf(stderr, "%s: Out of memory in e_advect_rbf()\n", progname);
321			exit(1);
322			return(NULL); /* pro forma return */
323			}
324
325			/* Partially advect between recorded incident angles and allocate new RBF */
326			RBFNODE *
327			advect_rbf(const FVECT invec)
328			{
329			FVECT sivec;
330			MIGRATION *miga[3];
331			RBFNODE *rbf;
332			int sym;
333			float mbfact, mcfact;
334			int n, i, j, k;
335			FVECT v0, v1, v2;
336	greg	2.8	double s, t;
337	greg	2.1
338			VCOPY(sivec, invec); /* find triangle/edge */
339			sym = get_interp(miga, sivec);
340			if (sym < 0) /* can't interpolate? */
341			return(NULL);
342			if (miga[1] == NULL) { /* advect along edge? */
343			rbf = e_advect_rbf(miga[0], sivec);
344	greg	2.5	if (single_plane_incident)
345			rotate_rbf(rbf, invec);
346			else
347			rev_rbf_symmetry(rbf, sym);
348	greg	2.1	return(rbf);
349			}
350			#ifdef DEBUG
351			if (miga[0]->rbfv[0] != miga[2]->rbfv[0] \|
352			miga[0]->rbfv[1] != miga[1]->rbfv[0] \|
353			miga[1]->rbfv[1] != miga[2]->rbfv[1]) {
354			fprintf(stderr, "%s: Triangle vertex screw-up!\n", progname);
355			exit(1);
356			}
357			#endif
358			/* figure out position */
359			fcross(v0, miga[2]->rbfv[0]->invec, miga[2]->rbfv[1]->invec);
360			normalize(v0);
361			fcross(v2, miga[1]->rbfv[0]->invec, miga[1]->rbfv[1]->invec);
362			normalize(v2);
363			fcross(v1, sivec, miga[1]->rbfv[1]->invec);
364			normalize(v1);
365	greg	2.7	s = acos(DOT(v0,v1)) / acos(DOT(v0,v2));
366	greg	2.1	geodesic(v1, miga[0]->rbfv[0]->invec, miga[0]->rbfv[1]->invec,
367	greg	2.7	s, GEOD_REL);
368	greg	2.8	t = acos(DOT(v1,sivec)) / acos(DOT(v1,miga[1]->rbfv[1]->invec));
369	greg	2.1	n = 0; /* count migrating particles */
370			for (i = 0; i < mtx_nrows(miga[0]); i++)
371			for (j = 0; j < mtx_ncols(miga[0]); j++)
372	greg	2.2	for (k = (mtx_coef(miga[0],i,j) > FTINY) *
373	greg	2.1	mtx_ncols(miga[2]); k--; )
374	greg	2.4	n += (mtx_coef(miga[2],i,k) > FTINY \|\|
375	greg	2.2	mtx_coef(miga[1],j,k) > FTINY);
376	greg	2.1	#ifdef DEBUG
377			fprintf(stderr, "Input RBFs have %d, %d, %d nodes -> output has %d\n",
378			miga[0]->rbfv[0]->nrbf, miga[0]->rbfv[1]->nrbf,
379			miga[2]->rbfv[1]->nrbf, n);
380			#endif
381			rbf = (RBFNODE )malloc(sizeof(RBFNODE) + sizeof(RBFVAL)(n-1));
382			if (rbf == NULL) {
383			fprintf(stderr, "%s: Out of memory in advect_rbf()\n", progname);
384			exit(1);
385			}
386			rbf->next = NULL; rbf->ejl = NULL;
387			VCOPY(rbf->invec, sivec);
388			rbf->nrbf = n;
389			n = 0; /* compute RBF lobes */
390			mbfact = s * miga[0]->rbfv[1]->vtotal/miga[0]->rbfv[0]->vtotal *
391			(1.-t + t*miga[1]->rbfv[1]->vtotal/miga[1]->rbfv[0]->vtotal);
392			mcfact = (1.-s) *
393			(1.-t + t*miga[2]->rbfv[1]->vtotal/miga[2]->rbfv[0]->vtotal);
394			for (i = 0; i < mtx_nrows(miga[0]); i++) {
395			const RBFVAL *rbf0i = &miga[0]->rbfv[0]->rbfa[i];
396			const float w0i = rbf0i->peak;
397			const double rad0i = R2ANG(rbf0i->crad);
398			ovec_from_pos(v0, rbf0i->gx, rbf0i->gy);
399			for (j = 0; j < mtx_ncols(miga[0]); j++) {
400	greg	2.2	const float ma = mtx_coef(miga[0],i,j);
401	greg	2.1	const RBFVAL *rbf1j;
402			double rad1j, srad2;
403			if (ma <= FTINY)
404			continue;
405			rbf1j = &miga[0]->rbfv[1]->rbfa[j];
406			rad1j = R2ANG(rbf1j->crad);
407			srad2 = (1.-s)(1.-t)rad0irad0i + s(1.-t)rad1jrad1j;
408			ovec_from_pos(v1, rbf1j->gx, rbf1j->gy);
409	greg	2.7	geodesic(v1, v0, v1, s, GEOD_REL);
410	greg	2.1	for (k = 0; k < mtx_ncols(miga[2]); k++) {
411	greg	2.2	float mb = mtx_coef(miga[1],j,k);
412			float mc = mtx_coef(miga[2],i,k);
413	greg	2.1	const RBFVAL *rbf2k;
414			double rad2k;
415			int pos[2];
416	greg	2.4	if ((mb <= FTINY) & (mc <= FTINY))
417	greg	2.1	continue;
418			rbf2k = &miga[2]->rbfv[1]->rbfa[k];
419			rbf->rbfa[n].peak = w0i * ma * (mbmbfact + mcmcfact);
420			rad2k = R2ANG(rbf2k->crad);
421			rbf->rbfa[n].crad = ANG2R(sqrt(srad2 + trad2krad2k));
422			ovec_from_pos(v2, rbf2k->gx, rbf2k->gy);
423	greg	2.8	geodesic(v2, v1, v2, t, GEOD_REL);
424			pos_from_vec(pos, v2);
425	greg	2.1	rbf->rbfa[n].gx = pos[0];
426			rbf->rbfa[n].gy = pos[1];
427			++n;
428			}
429			}
430			}
431			rbf->vtotal = miga[0]->rbfv[0]->vtotal * (mbfact + mcfact);
432			rev_rbf_symmetry(rbf, sym);
433			return(rbf);
434			}