src/gen/mkillum2.c

#ifndef lint
static const char       RCSid[] = "$Id: mkillum2.c,v 2.33 2009/09/08 23:05:47 greg Exp $";
#endif
/*
 * Routines to do the actual calculation for mkillum
 */

#include <string.h>

#include  "mkillum.h"
#include  "face.h"
#include  "cone.h"
#include  "source.h"

#ifndef NBSDFSAMPS
#define NBSDFSAMPS      256             /* BSDF resampling count */
#endif

COLORV *        distarr = NULL;         /* distribution array */
int             distsiz = 0;
COLORV *        direct_discount = NULL; /* amount to take off direct */


void
newdist(                        /* allocate & clear distribution array */
        int siz
)
{
        if (siz <= 0) {
                if (distsiz > 0)
                        free((void *)distarr);
                distarr = NULL;
                distsiz = 0;
                return;
        }
        if (distsiz < siz) {
                if (distsiz > 0)
                        free((void *)distarr);
                distarr = (COLORV *)malloc(sizeof(COLOR)*siz);
                if (distarr == NULL)
                        error(SYSTEM, "out of memory in newdist");
                distsiz = siz;
        }
        memset(distarr, '\0', sizeof(COLOR)*siz);
}


static void
new_discount()                  /* allocate space for direct contrib. record */
{
        if (distsiz <= 0)
                return;
        direct_discount = (COLORV *)calloc(distsiz, sizeof(COLOR));
        if (direct_discount == NULL)
                error(SYSTEM, "out of memory in new_discount");
}


static void
done_discount()                 /* clear off direct contrib. record */
{
        if (direct_discount == NULL)
                return;
        free((void *)direct_discount);
        direct_discount = NULL;
}


int
process_ray(                    /* process a ray result or report error */
        RAY *r,
        int rv
)
{
        COLORV  *colp;

        if (rv == 0)                    /* no result ready */
                return(0);
        if (rv < 0)
                error(USER, "ray tracing process died");
        if (r->rno >= distsiz)
                error(INTERNAL, "bad returned index in process_ray");
        multcolor(r->rcol, r->rcoef);   /* in case it's a source ray */
        colp = &distarr[r->rno * 3];
        addcolor(colp, r->rcol);
        if (r->rsrc >= 0 &&             /* remember source contrib. */
                        direct_discount != NULL) {
                colp = &direct_discount[r->rno * 3];
                addcolor(colp, r->rcol);
        }
        return(1);
}


void
raysamp(                        /* queue a ray sample */
        int  ndx,
        FVECT  org,
        FVECT  dir
)
{
        RAY     myRay;
        int     rv;

        if ((ndx < 0) | (ndx >= distsiz))
                error(INTERNAL, "bad index in raysamp");
        VCOPY(myRay.rorg, org);
        VCOPY(myRay.rdir, dir);
        myRay.rmax = .0;
        rayorigin(&myRay, PRIMARY, NULL, NULL);
        myRay.rno = ndx;
                                        /* queue ray, check result */
        process_ray(&myRay, ray_pqueue(&myRay));
}


void
srcsamps(                       /* sample sources from this surface position */
        struct illum_args *il,
        FVECT org,
        FVECT nrm,
        MAT4 ixfm
)
{
        int  nalt, nazi;
        SRCINDEX  si;
        RAY  sr;
        FVECT   v;
        double  d;
        int  i, j;
                                                /* get sampling density */
        if (il->sampdens <= 0) {
                nalt = nazi = 1;
        } else {
                i = PI * il->sampdens;
                nalt = sqrt(i/PI) + .5;
                nazi = PI*nalt + .5;
        }
        initsrcindex(&si);                      /* loop over (sub)sources */
        for ( ; ; ) {
                VCOPY(sr.rorg, org);            /* pick side to shoot from */
                if (il->sd != NULL) {
                        int  sn = si.sn;
                        if (si.sp+1 >= si.np) ++sn;
                        if (sn >= nsources) break;
                        if (source[sn].sflags & SDISTANT)
                                d = DOT(source[sn].sloc, nrm);
                        else {
                                VSUB(v, source[sn].sloc, org);
                                d = DOT(v, nrm);
                        }
                } else
                        d = 1.0;                /* only transmission */
                if (d < 0.0)
                        d = -1.0001*il->thick - 5.*FTINY;
                else
                        d = 5.*FTINY;
                for (i = 3; i--; )
                        sr.rorg[i] += d*nrm[i];
                samplendx++;                    /* increment sample counter */
                if (!srcray(&sr, NULL, &si))
                        break;                  /* end of sources */
                                                /* index direction */
                if (ixfm != NULL)
                        multv3(v, sr.rdir, ixfm);
                else
                        VCOPY(v, sr.rdir);
                if (il->sd != NULL) {
                        i = getBSDF_incndx(il->sd, v);
                        if (i < 0)
                                continue;       /* must not be important */
                        sr.rno = i;
                        d = 1.0/getBSDF_incohm(il->sd, i);
                } else {
                        if (v[2] >= -FTINY)
                                continue;       /* only sample transmission */
                        v[0] = -v[0]; v[1] = -v[1]; v[2] = -v[2];
                        sr.rno = flatindex(v, nalt, nazi);
                        d = nalt*nazi*(1./PI) * v[2];
                }
                d *= si.dom;                    /* solid angle correction */
                scalecolor(sr.rcoef, d);
                process_ray(&sr, ray_pqueue(&sr));
        }
}


void
rayclean()                      /* finish all pending rays */
{
        RAY     myRay;

        while (process_ray(&myRay, ray_presult(&myRay, 0)))
                ;
}


static void
mkaxes(                 /* compute u and v to go with n */
        FVECT  u,
        FVECT  v,
        FVECT  n
)
{
        register int  i;

        v[0] = v[1] = v[2] = 0.0;
        for (i = 0; i < 3; i++)
                if (n[i] < 0.6 && n[i] > -0.6)
                        break;
        v[i] = 1.0;
        fcross(u, v, n);
        normalize(u);
        fcross(v, n, u);
}


static void
rounddir(               /* compute uniform spherical direction */
        register FVECT  dv,
        double  alt,
        double  azi
)
{
        double  d1, d2;

        dv[2] = 1. - 2.*alt;
        d1 = sqrt(1. - dv[2]*dv[2]);
        d2 = 2.*PI * azi;
        dv[0] = d1*cos(d2);
        dv[1] = d1*sin(d2);
}


void
flatdir(                /* compute uniform hemispherical direction */
        FVECT  dv,
        double  alt,
        double  azi
)
{
        double  d1, d2;

        d1 = sqrt(alt);
        d2 = 2.*PI * azi;
        dv[0] = d1*cos(d2);
        dv[1] = d1*sin(d2);
        dv[2] = sqrt(1. - alt);
}

int
flatindex(              /* compute index for hemispherical direction */
        FVECT   dv,
        int     nalt,
        int     nazi
)
{
        double  d;
        int     i, j;
        
        d = 1.0 - dv[2]*dv[2];
        i = d*nalt;
        d = atan2(dv[1], dv[0]) * (0.5/PI);
        if (d < 0.0) d += 1.0;
        j = d*nazi + 0.5;
        if (j >= nazi) j = 0;
        return(i*nazi + j);
}


int
my_default(     /* default illum action */
        OBJREC  *ob,
        struct illum_args  *il,
        char  *nm
)
{
        sprintf(errmsg, "(%s): cannot make illum for %s \"%s\"",
                        nm, ofun[ob->otype].funame, ob->oname);
        error(WARNING, errmsg);
        printobj(il->altmat, ob);
        return(1);
}


int
my_face(                /* make an illum face */
        OBJREC  *ob,
        struct illum_args  *il,
        char  *nm
)
{
        int  dim[2];
        int  n, nalt, nazi, alti;
        double  sp[2], r1, r2;
        int  h;
        FVECT  dn, org, dir;
        FVECT  u, v;
        double  ur[2], vr[2];
        MAT4  xfm;
        int  nallow;
        FACE  *fa;
        int  i, j;
                                /* get/check arguments */
        fa = getface(ob);
        if (fa->area == 0.0) {
                freeface(ob);
                return(my_default(ob, il, nm));
        }
                                /* set up sampling */
        if (il->sd != NULL) {
                if (!getBSDF_xfm(xfm, fa->norm, il->udir)) {
                        objerror(ob, WARNING, "illegal up direction");
                        freeface(ob);
                        return(my_default(ob, il, nm));
                }
                n = il->sd->ninc;
        } else {
                if (il->sampdens <= 0) {
                        nalt = nazi = 1;        /* diffuse assumption */
                } else {
                        n = PI * il->sampdens;
                        nalt = sqrt(n/PI) + .5;
                        nazi = PI*nalt + .5;
                }
                n = nazi*nalt;
        }
        newdist(n);
                                /* take first edge >= sqrt(area) */
        for (j = fa->nv-1, i = 0; i < fa->nv; j = i++) {
                u[0] = VERTEX(fa,i)[0] - VERTEX(fa,j)[0];
                u[1] = VERTEX(fa,i)[1] - VERTEX(fa,j)[1];
                u[2] = VERTEX(fa,i)[2] - VERTEX(fa,j)[2];
                if ((r1 = DOT(u,u)) >= fa->area-FTINY)
                        break;
        }
        if (i < fa->nv) {       /* got one! -- let's align our axes */
                r2 = 1.0/sqrt(r1);
                u[0] *= r2; u[1] *= r2; u[2] *= r2;
                fcross(v, fa->norm, u);
        } else                  /* oh well, we'll just have to wing it */
                mkaxes(u, v, fa->norm);
                                /* now, find limits in (u,v) coordinates */
        ur[0] = vr[0] = FHUGE;
        ur[1] = vr[1] = -FHUGE;
        for (i = 0; i < fa->nv; i++) {
                r1 = DOT(VERTEX(fa,i),u);
                if (r1 < ur[0]) ur[0] = r1;
                if (r1 > ur[1]) ur[1] = r1;
                r2 = DOT(VERTEX(fa,i),v);
                if (r2 < vr[0]) vr[0] = r2;
                if (r2 > vr[1]) vr[1] = r2;
        }
        dim[0] = random();
                                /* sample polygon */
        nallow = 5*n*il->nsamps;
        for (dim[1] = 0; dim[1] < n; dim[1]++)
                for (i = 0; i < il->nsamps; i++) {
                                        /* randomize direction */
                    h = ilhash(dim, 2) + i;
                    if (il->sd != NULL) {
                        r_BSDF_incvec(dir, il->sd, dim[1], urand(h), xfm);
                    } else {
                        multisamp(sp, 2, urand(h));
                        alti = dim[1]/nazi;
                        r1 = (alti + sp[0])/nalt;
                        r2 = (dim[1] - alti*nazi + sp[1] - .5)/nazi;
                        flatdir(dn, r1, r2);
                        for (j = 0; j < 3; j++)
                            dir[j] = -dn[0]*u[j] - dn[1]*v[j] -
                                                dn[2]*fa->norm[j];
                    }
                                        /* randomize location */
                    do {
                        multisamp(sp, 2, urand(h+4862+nallow));
                        r1 = ur[0] + (ur[1]-ur[0]) * sp[0];
                        r2 = vr[0] + (vr[1]-vr[0]) * sp[1];
                        for (j = 0; j < 3; j++)
                            org[j] = r1*u[j] + r2*v[j]
                                        + fa->offset*fa->norm[j];
                    } while (!inface(org, fa) && nallow-- > 0);
                    if (nallow < 0) {
                        objerror(ob, WARNING, "bad aspect");
                        rayclean();
                        freeface(ob);
                        return(my_default(ob, il, nm));
                    }
                    if (il->sd != NULL && DOT(dir, fa->norm) < -FTINY)
                        r1 = -1.0001*il->thick - 5.*FTINY;
                    else
                        r1 = 5.*FTINY;
                    for (j = 0; j < 3; j++)
                        org[j] += r1*fa->norm[j];
                                        /* send sample */
                    raysamp(dim[1], org, dir);
                }
                                /* add in direct component? */
        if (!directvis && (il->flags & IL_LIGHT || il->sd != NULL)) {
                MAT4    ixfm;
                if (il->sd == NULL) {
                        for (i = 3; i--; ) {
                                ixfm[i][0] = u[i];
                                ixfm[i][1] = v[i];
                                ixfm[i][2] = fa->norm[i];
                                ixfm[i][3] = 0.;
                        }
                        ixfm[3][0] = ixfm[3][1] = ixfm[3][2] = 0.;
                        ixfm[3][3] = 1.;
                } else {
                        if (!invmat4(ixfm, xfm))
                                objerror(ob, INTERNAL,
                                        "cannot invert BSDF transform");
                        if (!(il->flags & IL_LIGHT))
                                new_discount();
                }
                dim[0] = random();
                nallow = 10*il->nsamps;
                for (i = 0; i < il->nsamps; i++) {
                                        /* randomize location */
                    h = dim[0] + samplendx++;
                    do {
                        multisamp(sp, 2, urand(h+nallow));
                        r1 = ur[0] + (ur[1]-ur[0]) * sp[0];
                        r2 = vr[0] + (vr[1]-vr[0]) * sp[1];
                        for (j = 0; j < 3; j++)
                            org[j] = r1*u[j] + r2*v[j]
                                        + fa->offset*fa->norm[j];
                    } while (!inface(org, fa) && nallow-- > 0);
                    if (nallow < 0) {
                        objerror(ob, WARNING, "bad aspect");
                        rayclean();
                        freeface(ob);
                        return(my_default(ob, il, nm));
                    }
                                        /* sample source rays */
                    srcsamps(il, org, fa->norm, ixfm);
                }
        }
                                /* wait for all rays to finish */
        rayclean();
        if (il->sd != NULL) {   /* run distribution through BSDF */
                nalt = sqrt(il->sd->nout/PI) + .5;
                nazi = PI*nalt + .5;
                redistribute(il->sd, nalt, nazi, u, v, fa->norm, xfm);
                done_discount();
                if (!il->sampdens)
                        il->sampdens = nalt*nazi/PI + .999;
        }
                                /* write out the face and its distribution */
        if (average(il, distarr, n)) {
                if (il->sampdens > 0)
                        flatout(il, distarr, nalt, nazi, u, v, fa->norm);
                illumout(il, ob);
        } else
                printobj(il->altmat, ob);
                                /* clean up */
        freeface(ob);
        return(0);
}


int
my_sphere(      /* make an illum sphere */
        register OBJREC  *ob,
        struct illum_args  *il,
        char  *nm
)
{
        int  dim[3];
        int  n, nalt, nazi;
        double  sp[4], r1, r2, r3;
        FVECT  org, dir;
        FVECT  u, v;
        register int  i, j;
                                /* check arguments */
        if (ob->oargs.nfargs != 4)
                objerror(ob, USER, "bad # of arguments");
                                /* set up sampling */
        if (il->sampdens <= 0)
                nalt = nazi = 1;
        else {
                n = 4.*PI * il->sampdens;
                nalt = sqrt(2./PI*n) + .5;
                nazi = PI/2.*nalt + .5;
        }
        if (il->sd != NULL)
                objerror(ob, WARNING, "BSDF ignored");
        n = nalt*nazi;
        newdist(n);
        dim[0] = random();
                                /* sample sphere */
        for (dim[1] = 0; dim[1] < nalt; dim[1]++)
            for (dim[2] = 0; dim[2] < nazi; dim[2]++)
                for (i = 0; i < il->nsamps; i++) {
                                        /* next sample point */
                    multisamp(sp, 4, urand(ilhash(dim,3)+i));
                                        /* random direction */
                    r1 = (dim[1] + sp[0])/nalt;
                    r2 = (dim[2] + sp[1] - .5)/nazi;
                    rounddir(dir, r1, r2);
                                        /* random location */
                    mkaxes(u, v, dir);          /* yuck! */
                    r3 = sqrt(sp[2]);
                    r2 = 2.*PI*sp[3];
                    r1 = r3*ob->oargs.farg[3]*cos(r2);
                    r2 = r3*ob->oargs.farg[3]*sin(r2);
                    r3 = ob->oargs.farg[3]*sqrt(1.01-r3*r3);
                    for (j = 0; j < 3; j++) {
                        org[j] = ob->oargs.farg[j] + r1*u[j] + r2*v[j] +
                                        r3*dir[j];
                        dir[j] = -dir[j];
                    }
                                        /* send sample */
                    raysamp(dim[1]*nazi+dim[2], org, dir);
                }
                                /* wait for all rays to finish */
        rayclean();
                                /* write out the sphere and its distribution */
        if (average(il, distarr, n)) {
                if (il->sampdens > 0)
                        roundout(il, distarr, nalt, nazi);
                else
                        objerror(ob, WARNING, "diffuse distribution");
                illumout(il, ob);
        } else
                printobj(il->altmat, ob);
                                /* clean up */
        return(1);
}


int
my_ring(                /* make an illum ring */
        OBJREC  *ob,
        struct illum_args  *il,
        char  *nm
)
{
        int  dim[2];
        int  n, nalt, nazi, alti;
        double  sp[2], r1, r2, r3;
        int  h;
        FVECT  dn, org, dir;
        FVECT  u, v;
        MAT4  xfm;
        CONE  *co;
        int  i, j;
                                /* get/check arguments */
        co = getcone(ob, 0);
                                /* set up sampling */
        if (il->sd != NULL) {
                if (!getBSDF_xfm(xfm, co->ad, il->udir)) {
                        objerror(ob, WARNING, "illegal up direction");
                        freecone(ob);
                        return(my_default(ob, il, nm));
                }
                n = il->sd->ninc;
        } else {
                if (il->sampdens <= 0) {
                        nalt = nazi = 1;        /* diffuse assumption */
                } else {
                        n = PI * il->sampdens;
                        nalt = sqrt(n/PI) + .5;
                        nazi = PI*nalt + .5;
                }
                n = nazi*nalt;
        }
        newdist(n);
        mkaxes(u, v, co->ad);
        dim[0] = random();
                                /* sample disk */
        for (dim[1] = 0; dim[1] < n; dim[1]++)
                for (i = 0; i < il->nsamps; i++) {
                                        /* next sample point */
                    h = ilhash(dim,2) + i;
                                        /* randomize direction */
                    if (il->sd != NULL) {
                        r_BSDF_incvec(dir, il->sd, dim[1], urand(h), xfm);
                    } else {
                        multisamp(sp, 2, urand(h));
                        alti = dim[1]/nazi;
                        r1 = (alti + sp[0])/nalt;
                        r2 = (dim[1] - alti*nazi + sp[1] - .5)/nazi;
                        flatdir(dn, r1, r2);
                        for (j = 0; j < 3; j++)
                                dir[j] = -dn[0]*u[j] - dn[1]*v[j] - dn[2]*co->ad[j];
                    }
                                        /* randomize location */
                    multisamp(sp, 2, urand(h+8371));
                    r3 = sqrt(CO_R0(co)*CO_R0(co) +
                            sp[0]*(CO_R1(co)*CO_R1(co) - CO_R0(co)*CO_R0(co)));
                    r2 = 2.*PI*sp[1];
                    r1 = r3*cos(r2);
                    r2 = r3*sin(r2);
                    if (il->sd != NULL && DOT(dir, co->ad) < -FTINY)
                        r3 = -1.0001*il->thick - 5.*FTINY;
                    else
                        r3 = 5.*FTINY;
                    for (j = 0; j < 3; j++)
                        org[j] = CO_P0(co)[j] + r1*u[j] + r2*v[j] +
                                                r3*co->ad[j];
                                        /* send sample */
                    raysamp(dim[1], org, dir);
                }
                                /* add in direct component? */
        if (!directvis && (il->flags & IL_LIGHT || il->sd != NULL)) {
                MAT4    ixfm;
                if (il->sd == NULL) {
                        for (i = 3; i--; ) {
                                ixfm[i][0] = u[i];
                                ixfm[i][1] = v[i];
                                ixfm[i][2] = co->ad[i];
                                ixfm[i][3] = 0.;
                        }
                        ixfm[3][0] = ixfm[3][1] = ixfm[3][2] = 0.;
                        ixfm[3][3] = 1.;
                } else {
                        if (!invmat4(ixfm, xfm))
                                objerror(ob, INTERNAL,
                                        "cannot invert BSDF transform");
                        if (!(il->flags & IL_LIGHT))
                                new_discount();
                }
                dim[0] = random();
                for (i = 0; i < il->nsamps; i++) {
                                        /* randomize location */
                    h = dim[0] + samplendx++;
                    multisamp(sp, 2, urand(h));
                    r3 = sqrt(CO_R0(co)*CO_R0(co) +
                            sp[0]*(CO_R1(co)*CO_R1(co) - CO_R0(co)*CO_R0(co)));
                    r2 = 2.*PI*sp[1];
                    r1 = r3*cos(r2);
                    r2 = r3*sin(r2);
                    for (j = 0; j < 3; j++)
                        org[j] = CO_P0(co)[j] + r1*u[j] + r2*v[j];
                                        /* sample source rays */
                    srcsamps(il, org, co->ad, ixfm);
                }
        }
                                /* wait for all rays to finish */
        rayclean();
        if (il->sd != NULL) {   /* run distribution through BSDF */
                nalt = sqrt(il->sd->nout/PI) + .5;
                nazi = PI*nalt + .5;
                redistribute(il->sd, nalt, nazi, u, v, co->ad, xfm);
                done_discount();
                if (!il->sampdens)
                        il->sampdens = nalt*nazi/PI + .999;
        }
                                /* write out the ring and its distribution */
        if (average(il, distarr, n)) {
                if (il->sampdens > 0)
                        flatout(il, distarr, nalt, nazi, u, v, co->ad);
                illumout(il, ob);
        } else
                printobj(il->altmat, ob);
                                /* clean up */
        freecone(ob);
        return(1);
}


void
redistribute(           /* pass distarr ray sums through BSDF */
        struct BSDF_data *b,
        int nalt,
        int nazi,
        FVECT u,
        FVECT v,
        FVECT w,
        MAT4 xm
)
{
        int     nout = 0;
        MAT4    mymat, inmat;
        COLORV  *idist;
        COLORV  *cp;
        FVECT   dv;
        double  wt;
        int     i, j, k, c, o;
        COLOR   col, cinc;
                                        /* copy incoming distribution */
        if (b->ninc > distsiz)
                error(INTERNAL, "error 1 in redistribute");
        idist = (COLORV *)malloc(sizeof(COLOR)*b->ninc);
        if (idist == NULL)
                error(SYSTEM, "out of memory in redistribute");
        memcpy(idist, distarr, sizeof(COLOR)*b->ninc);
                                        /* compose direction transform */
        for (i = 3; i--; ) {
                mymat[i][0] = u[i];
                mymat[i][1] = v[i];
                mymat[i][2] = w[i];
                mymat[i][3] = 0.;
        }
        mymat[3][0] = mymat[3][1] = mymat[3][2] = 0.;
        mymat[3][3] = 1.;
        if (xm != NULL)
                multmat4(mymat, xm, mymat);
        for (i = 3; i--; ) {            /* make sure it's normalized */
                wt = 1./sqrt(   mymat[0][i]*mymat[0][i] +
                                mymat[1][i]*mymat[1][i] +
                                mymat[2][i]*mymat[2][i] );
                for (j = 3; j--; )
                        mymat[j][i] *= wt;
        }
        if (!invmat4(inmat, mymat))     /* need inverse as well */
                error(INTERNAL, "cannot invert BSDF transform");
        newdist(nalt*nazi);             /* resample distribution */
        for (i = b->ninc; i--; ) {
                int     direct_out = -1;
                COLOR   cdir;
                getBSDF_incvec(dv, b, i);       /* compute incident irrad. */
                multv3(dv, dv, mymat);
                if (dv[2] < 0.0) {
                        dv[0] = -dv[0]; dv[1] = -dv[1]; dv[2] = -dv[2];
                        direct_out += (direct_discount != NULL);
                }
                wt = getBSDF_incohm(b, i);
                wt *= dv[2];                    /* solid_angle*cosine(theta) */
                cp = &idist[3*i];
                copycolor(cinc, cp);
                scalecolor(cinc, wt);
                if (!direct_out) {              /* discount direct contr. */
                        cp = &direct_discount[3*i];
                        copycolor(cdir, cp);
                        scalecolor(cdir, -wt);
                        if (b->nout != b->ninc)
                                direct_out = flatindex(dv, nalt, nazi);
                        else
                                direct_out = i; /* assumes dist. mirroring */
                }
                for (k = nalt; k--; )           /* loop over distribution */
                  for (j = nazi; j--; ) {
                    int rstart = random();
                    for (c = NBSDFSAMPS; c--; ) {
                        double  sp[2];
                        multisamp(sp, 2, urand(rstart+c));
                        flatdir(dv, (k + sp[0])/nalt,
                                        (j + .5 - sp[1])/nazi);
                        multv3(dv, dv, inmat);
                                                /* evaluate BSDF @ outgoing */
                        o = getBSDF_outndx(b, dv);
                        if (o < 0) {
                                nout++;
                                continue;
                        }
                        wt = BSDF_value(b, i, o) * (1./NBSDFSAMPS);
                        copycolor(col, cinc);
                        if (b->nout != b->ninc)
                                o = k*nazi + j;
                        if (o == direct_out)
                                addcolor(col, cdir);    /* minus direct */
                        scalecolor(col, wt);
                        cp = &distarr[3*(k*nazi + j)];
                        addcolor(cp, col);      /* sum into distribution */
                    }
                  }
        }
        free(idist);                    /* free temp space */
        if (nout) {
                sprintf(errmsg, "missing %.1f%% of BSDF directions",
                                100.*nout/(b->ninc*nalt*nazi*NBSDFSAMPS));
                error(WARNING, errmsg);
        }
}
Revision:	2.34
Committed:	Wed Sep 9 15:32:20 2009 UTC (14 years, 7 months ago) by greg
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rad4R0
Changes since 2.33:	+2 -2 lines
Log Message:	Fixed bug introduced in last bug-fix.
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.34	static const char RCSid[] = "$Id: mkillum2.c,v 2.33 2009/09/08 23:05:47 greg Exp $";
3	greg	1.1	#endif
4			/*
5	greg	1.4	* Routines to do the actual calculation for mkillum
6	greg	1.1	*/
7
8	schorsch	2.11	#include <string.h>
9
10	greg	1.1	#include "mkillum.h"
11			#include "face.h"
12			#include "cone.h"
13	greg	2.25	#include "source.h"
14	greg	1.1
15	greg	2.31	#ifndef NBSDFSAMPS
16	greg	2.32	#define NBSDFSAMPS 256 /* BSDF resampling count */
17	greg	2.31	#endif
18	greg	2.13
19	greg	2.21	COLORV * distarr = NULL; /* distribution array */
20			int distsiz = 0;
21	greg	2.29	COLORV * direct_discount = NULL; /* amount to take off direct */
22	greg	2.16
23	greg	2.31
24	greg	2.21	void
25	greg	2.18	newdist( /* allocate & clear distribution array */
26			int siz
27			)
28			{
29	greg	2.24	if (siz <= 0) {
30	greg	2.18	if (distsiz > 0)
31			free((void *)distarr);
32			distarr = NULL;
33			distsiz = 0;
34			return;
35			}
36			if (distsiz < siz) {
37	greg	2.21	if (distsiz > 0)
38			free((void *)distarr);
39			distarr = (COLORV )malloc(sizeof(COLOR)siz);
40	greg	2.18	if (distarr == NULL)
41	greg	2.20	error(SYSTEM, "out of memory in newdist");
42	greg	2.18	distsiz = siz;
43			}
44	greg	2.21	memset(distarr, '\0', sizeof(COLOR)*siz);
45	greg	2.18	}
46
47
48	greg	2.29	static void
49			new_discount() /* allocate space for direct contrib. record */
50			{
51			if (distsiz <= 0)
52			return;
53			direct_discount = (COLORV *)calloc(distsiz, sizeof(COLOR));
54			if (direct_discount == NULL)
55			error(SYSTEM, "out of memory in new_discount");
56			}
57
58
59			static void
60			done_discount() /* clear off direct contrib. record */
61			{
62			if (direct_discount == NULL)
63			return;
64			free((void *)direct_discount);
65			direct_discount = NULL;
66			}
67
68
69	greg	2.21	int
70	greg	2.25	process_ray( /* process a ray result or report error */
71			RAY *r,
72			int rv
73			)
74	greg	2.18	{
75			COLORV *colp;
76
77	greg	2.24	if (rv == 0) /* no result ready */
78	greg	2.18	return(0);
79			if (rv < 0)
80	greg	2.20	error(USER, "ray tracing process died");
81	greg	2.18	if (r->rno >= distsiz)
82	greg	2.20	error(INTERNAL, "bad returned index in process_ray");
83	greg	2.25	multcolor(r->rcol, r->rcoef); /* in case it's a source ray */
84	greg	2.18	colp = &distarr[r->rno * 3];
85			addcolor(colp, r->rcol);
86	greg	2.29	if (r->rsrc >= 0 && /* remember source contrib. */
87			direct_discount != NULL) {
88			colp = &direct_discount[r->rno * 3];
89			addcolor(colp, r->rcol);
90			}
91	greg	2.18	return(1);
92			}
93
94
95	greg	2.21	void
96	greg	2.25	raysamp( /* queue a ray sample */
97	greg	2.18	int ndx,
98			FVECT org,
99			FVECT dir
100	greg	2.16	)
101			{
102	greg	2.18	RAY myRay;
103			int rv;
104
105			if ((ndx < 0) \| (ndx >= distsiz))
106	greg	2.20	error(INTERNAL, "bad index in raysamp");
107	greg	2.18	VCOPY(myRay.rorg, org);
108			VCOPY(myRay.rdir, dir);
109			myRay.rmax = .0;
110			rayorigin(&myRay, PRIMARY, NULL, NULL);
111			myRay.rno = ndx;
112			/* queue ray, check result */
113			process_ray(&myRay, ray_pqueue(&myRay));
114			}
115
116
117	greg	2.21	void
118	greg	2.25	srcsamps( /* sample sources from this surface position */
119			struct illum_args *il,
120			FVECT org,
121			FVECT nrm,
122			MAT4 ixfm
123			)
124			{
125			int nalt, nazi;
126			SRCINDEX si;
127			RAY sr;
128			FVECT v;
129			double d;
130			int i, j;
131			/* get sampling density */
132			if (il->sampdens <= 0) {
133			nalt = nazi = 1;
134			} else {
135			i = PI * il->sampdens;
136			nalt = sqrt(i/PI) + .5;
137			nazi = PI*nalt + .5;
138			}
139			initsrcindex(&si); /* loop over (sub)sources */
140			for ( ; ; ) {
141			VCOPY(sr.rorg, org); /* pick side to shoot from */
142			if (il->sd != NULL) {
143			int sn = si.sn;
144			if (si.sp+1 >= si.np) ++sn;
145			if (sn >= nsources) break;
146			if (source[sn].sflags & SDISTANT)
147			d = DOT(source[sn].sloc, nrm);
148			else {
149			VSUB(v, source[sn].sloc, org);
150			d = DOT(v, nrm);
151			}
152			} else
153			d = 1.0; /* only transmission */
154			if (d < 0.0)
155			d = -1.0001il->thick - 5.FTINY;
156			else
157			d = 5.*FTINY;
158			for (i = 3; i--; )
159			sr.rorg[i] += d*nrm[i];
160	greg	2.30	samplendx++; /* increment sample counter */
161	greg	2.25	if (!srcray(&sr, NULL, &si))
162			break; /* end of sources */
163			/* index direction */
164			if (ixfm != NULL)
165			multv3(v, sr.rdir, ixfm);
166			else
167			VCOPY(v, sr.rdir);
168			if (il->sd != NULL) {
169			i = getBSDF_incndx(il->sd, v);
170			if (i < 0)
171			continue; /* must not be important */
172			sr.rno = i;
173	greg	2.26	d = 1.0/getBSDF_incohm(il->sd, i);
174	greg	2.25	} else {
175			if (v[2] >= -FTINY)
176			continue; /* only sample transmission */
177	greg	2.29	v[0] = -v[0]; v[1] = -v[1]; v[2] = -v[2];
178			sr.rno = flatindex(v, nalt, nazi);
179			d = naltnazi(1./PI) * v[2];
180	greg	2.25	}
181			d = si.dom; / solid angle correction */
182			scalecolor(sr.rcoef, d);
183			process_ray(&sr, ray_pqueue(&sr));
184			}
185			}
186
187
188			void
189	greg	2.18	rayclean() /* finish all pending rays */
190			{
191			RAY myRay;
192
193			while (process_ray(&myRay, ray_presult(&myRay, 0)))
194	greg	2.16	;
195			}
196	schorsch	2.12
197
198	greg	2.21	static void
199			mkaxes( /* compute u and v to go with n */
200			FVECT u,
201			FVECT v,
202			FVECT n
203			)
204			{
205			register int i;
206
207			v[0] = v[1] = v[2] = 0.0;
208			for (i = 0; i < 3; i++)
209			if (n[i] < 0.6 && n[i] > -0.6)
210			break;
211			v[i] = 1.0;
212			fcross(u, v, n);
213			normalize(u);
214			fcross(v, n, u);
215			}
216
217
218			static void
219			rounddir( /* compute uniform spherical direction */
220			register FVECT dv,
221			double alt,
222			double azi
223			)
224			{
225			double d1, d2;
226
227			dv[2] = 1. - 2.*alt;
228			d1 = sqrt(1. - dv[2]*dv[2]);
229			d2 = 2.PI azi;
230			dv[0] = d1*cos(d2);
231			dv[1] = d1*sin(d2);
232			}
233
234
235	greg	2.24	void
236	greg	2.21	flatdir( /* compute uniform hemispherical direction */
237	greg	2.24	FVECT dv,
238	greg	2.21	double alt,
239			double azi
240			)
241			{
242			double d1, d2;
243
244			d1 = sqrt(alt);
245			d2 = 2.PI azi;
246			dv[0] = d1*cos(d2);
247			dv[1] = d1*sin(d2);
248			dv[2] = sqrt(1. - alt);
249			}
250
251	greg	2.29	int
252			flatindex( /* compute index for hemispherical direction */
253			FVECT dv,
254			int nalt,
255			int nazi
256			)
257			{
258			double d;
259			int i, j;
260
261			d = 1.0 - dv[2]*dv[2];
262			i = d*nalt;
263			d = atan2(dv[1], dv[0]) * (0.5/PI);
264			if (d < 0.0) d += 1.0;
265			j = d*nazi + 0.5;
266			if (j >= nazi) j = 0;
267			return(i*nazi + j);
268			}
269
270	greg	2.21
271	greg	2.19	int
272	greg	2.18	my_default( /* default illum action */
273	schorsch	2.12	OBJREC *ob,
274			struct illum_args *il,
275			char *nm
276			)
277	greg	1.1	{
278	greg	1.2	sprintf(errmsg, "(%s): cannot make illum for %s \"%s\"",
279			nm, ofun[ob->otype].funame, ob->oname);
280			error(WARNING, errmsg);
281	greg	2.2	printobj(il->altmat, ob);
282	greg	2.13	return(1);
283	greg	1.2	}
284
285
286	greg	2.13	int
287	greg	2.18	my_face( /* make an illum face */
288	schorsch	2.12	OBJREC *ob,
289			struct illum_args *il,
290			char *nm
291			)
292	greg	1.2	{
293	greg	2.21	int dim[2];
294	greg	2.25	int n, nalt, nazi, alti;
295	greg	1.10	double sp[2], r1, r2;
296	greg	2.25	int h;
297	greg	1.4	FVECT dn, org, dir;
298	greg	1.3	FVECT u, v;
299			double ur[2], vr[2];
300	greg	2.21	MAT4 xfm;
301	greg	2.25	int nallow;
302	greg	2.21	FACE *fa;
303	greg	2.25	int i, j;
304	greg	1.3	/* get/check arguments */
305			fa = getface(ob);
306			if (fa->area == 0.0) {
307			freeface(ob);
308	greg	2.19	return(my_default(ob, il, nm));
309	greg	1.3	}
310			/* set up sampling */
311	greg	2.21	if (il->sd != NULL) {
312			if (!getBSDF_xfm(xfm, fa->norm, il->udir)) {
313			objerror(ob, WARNING, "illegal up direction");
314			freeface(ob);
315			return(my_default(ob, il, nm));
316			}
317			n = il->sd->ninc;
318	greg	2.22	} else {
319			if (il->sampdens <= 0) {
320			nalt = nazi = 1; /* diffuse assumption */
321			} else {
322			n = PI * il->sampdens;
323			nalt = sqrt(n/PI) + .5;
324			nazi = PI*nalt + .5;
325			}
326	greg	2.21	n = nazi*nalt;
327	greg	2.22	}
328	greg	2.18	newdist(n);
329	greg	2.20	/* take first edge >= sqrt(area) */
330	greg	2.4	for (j = fa->nv-1, i = 0; i < fa->nv; j = i++) {
331			u[0] = VERTEX(fa,i)[0] - VERTEX(fa,j)[0];
332			u[1] = VERTEX(fa,i)[1] - VERTEX(fa,j)[1];
333			u[2] = VERTEX(fa,i)[2] - VERTEX(fa,j)[2];
334	greg	2.5	if ((r1 = DOT(u,u)) >= fa->area-FTINY)
335	greg	2.3	break;
336			}
337			if (i < fa->nv) { /* got one! -- let's align our axes */
338	greg	2.5	r2 = 1.0/sqrt(r1);
339			u[0] = r2; u[1] = r2; u[2] *= r2;
340	greg	2.3	fcross(v, fa->norm, u);
341			} else /* oh well, we'll just have to wing it */
342			mkaxes(u, v, fa->norm);
343			/* now, find limits in (u,v) coordinates */
344	greg	1.3	ur[0] = vr[0] = FHUGE;
345			ur[1] = vr[1] = -FHUGE;
346			for (i = 0; i < fa->nv; i++) {
347			r1 = DOT(VERTEX(fa,i),u);
348			if (r1 < ur[0]) ur[0] = r1;
349			if (r1 > ur[1]) ur[1] = r1;
350			r2 = DOT(VERTEX(fa,i),v);
351			if (r2 < vr[0]) vr[0] = r2;
352			if (r2 > vr[1]) vr[1] = r2;
353			}
354			dim[0] = random();
355			/* sample polygon */
356	greg	2.25	nallow = 5nil->nsamps;
357	greg	2.21	for (dim[1] = 0; dim[1] < n; dim[1]++)
358	greg	1.3	for (i = 0; i < il->nsamps; i++) {
359	greg	2.23	/* randomize direction */
360	greg	2.21	h = ilhash(dim, 2) + i;
361			if (il->sd != NULL) {
362			r_BSDF_incvec(dir, il->sd, dim[1], urand(h), xfm);
363			} else {
364			multisamp(sp, 2, urand(h));
365			alti = dim[1]/nazi;
366			r1 = (alti + sp[0])/nalt;
367			r2 = (dim[1] - alti*nazi + sp[1] - .5)/nazi;
368			flatdir(dn, r1, r2);
369			for (j = 0; j < 3; j++)
370			dir[j] = -dn[0]u[j] - dn[1]v[j] -
371			dn[2]*fa->norm[j];
372			}
373	greg	2.23	/* randomize location */
374	greg	1.3	do {
375	greg	2.25	multisamp(sp, 2, urand(h+4862+nallow));
376	greg	1.10	r1 = ur[0] + (ur[1]-ur[0]) * sp[0];
377			r2 = vr[0] + (vr[1]-vr[0]) * sp[1];
378	greg	1.3	for (j = 0; j < 3; j++)
379			org[j] = r1u[j] + r2v[j]
380			+ fa->offset*fa->norm[j];
381	greg	2.25	} while (!inface(org, fa) && nallow-- > 0);
382			if (nallow < 0) {
383	greg	1.3	objerror(ob, WARNING, "bad aspect");
384	greg	2.18	rayclean();
385	greg	1.3	freeface(ob);
386	greg	2.19	return(my_default(ob, il, nm));
387	greg	1.3	}
388	greg	2.21	if (il->sd != NULL && DOT(dir, fa->norm) < -FTINY)
389	greg	2.25	r1 = -1.0001il->thick - 5.FTINY;
390	greg	2.21	else
391	greg	2.25	r1 = 5.*FTINY;
392	greg	1.3	for (j = 0; j < 3; j++)
393	greg	2.21	org[j] += r1*fa->norm[j];
394	greg	1.3	/* send sample */
395	greg	2.21	raysamp(dim[1], org, dir);
396	greg	1.3	}
397	greg	2.25	/* add in direct component? */
398	greg	2.29	if (!directvis && (il->flags & IL_LIGHT \|\| il->sd != NULL)) {
399	greg	2.25	MAT4 ixfm;
400			if (il->sd == NULL) {
401			for (i = 3; i--; ) {
402			ixfm[i][0] = u[i];
403			ixfm[i][1] = v[i];
404			ixfm[i][2] = fa->norm[i];
405			ixfm[i][3] = 0.;
406			}
407			ixfm[3][0] = ixfm[3][1] = ixfm[3][2] = 0.;
408			ixfm[3][3] = 1.;
409	greg	2.29	} else {
410			if (!invmat4(ixfm, xfm))
411			objerror(ob, INTERNAL,
412			"cannot invert BSDF transform");
413			if (!(il->flags & IL_LIGHT))
414			new_discount();
415			}
416	greg	2.25	dim[0] = random();
417			nallow = 10*il->nsamps;
418			for (i = 0; i < il->nsamps; i++) {
419			/* randomize location */
420			h = dim[0] + samplendx++;
421			do {
422			multisamp(sp, 2, urand(h+nallow));
423			r1 = ur[0] + (ur[1]-ur[0]) * sp[0];
424			r2 = vr[0] + (vr[1]-vr[0]) * sp[1];
425			for (j = 0; j < 3; j++)
426			org[j] = r1u[j] + r2v[j]
427			+ fa->offset*fa->norm[j];
428			} while (!inface(org, fa) && nallow-- > 0);
429			if (nallow < 0) {
430			objerror(ob, WARNING, "bad aspect");
431			rayclean();
432			freeface(ob);
433			return(my_default(ob, il, nm));
434			}
435			/* sample source rays */
436			srcsamps(il, org, fa->norm, ixfm);
437			}
438			}
439			/* wait for all rays to finish */
440	greg	2.18	rayclean();
441	greg	2.22	if (il->sd != NULL) { /* run distribution through BSDF */
442			nalt = sqrt(il->sd->nout/PI) + .5;
443			nazi = PI*nalt + .5;
444	greg	2.21	redistribute(il->sd, nalt, nazi, u, v, fa->norm, xfm);
445	greg	2.29	done_discount();
446	greg	2.28	if (!il->sampdens)
447			il->sampdens = nalt*nazi/PI + .999;
448	greg	2.22	}
449	greg	1.11	/* write out the face and its distribution */
450	greg	2.21	if (average(il, distarr, n)) {
451	greg	1.12	if (il->sampdens > 0)
452			flatout(il, distarr, nalt, nazi, u, v, fa->norm);
453			illumout(il, ob);
454	greg	2.2	} else
455	greg	1.12	printobj(il->altmat, ob);
456	greg	1.3	/* clean up */
457			freeface(ob);
458	greg	2.15	return(0);
459	greg	1.2	}
460
461
462	greg	2.13	int
463	greg	2.18	my_sphere( /* make an illum sphere */
464	schorsch	2.12	register OBJREC *ob,
465			struct illum_args *il,
466			char *nm
467			)
468	greg	1.2	{
469	greg	1.10	int dim[3];
470	greg	1.2	int n, nalt, nazi;
471	greg	1.10	double sp[4], r1, r2, r3;
472	greg	1.4	FVECT org, dir;
473	greg	1.2	FVECT u, v;
474			register int i, j;
475			/* check arguments */
476			if (ob->oargs.nfargs != 4)
477			objerror(ob, USER, "bad # of arguments");
478			/* set up sampling */
479	greg	1.11	if (il->sampdens <= 0)
480			nalt = nazi = 1;
481			else {
482			n = 4.PI il->sampdens;
483	greg	2.7	nalt = sqrt(2./PI*n) + .5;
484			nazi = PI/2.*nalt + .5;
485	greg	1.11	}
486	greg	2.21	if (il->sd != NULL)
487			objerror(ob, WARNING, "BSDF ignored");
488	greg	1.2	n = nalt*nazi;
489	greg	2.18	newdist(n);
490	greg	1.2	dim[0] = random();
491			/* sample sphere */
492			for (dim[1] = 0; dim[1] < nalt; dim[1]++)
493	greg	1.8	for (dim[2] = 0; dim[2] < nazi; dim[2]++)
494	greg	1.2	for (i = 0; i < il->nsamps; i++) {
495	greg	1.10	/* next sample point */
496	greg	1.11	multisamp(sp, 4, urand(ilhash(dim,3)+i));
497	greg	1.2	/* random direction */
498	greg	1.10	r1 = (dim[1] + sp[0])/nalt;
499	greg	1.13	r2 = (dim[2] + sp[1] - .5)/nazi;
500	greg	1.2	rounddir(dir, r1, r2);
501			/* random location */
502	greg	1.8	mkaxes(u, v, dir); /* yuck! */
503	greg	1.10	r3 = sqrt(sp[2]);
504			r2 = 2.PIsp[3];
505	greg	1.5	r1 = r3ob->oargs.farg[3]cos(r2);
506			r2 = r3ob->oargs.farg[3]sin(r2);
507			r3 = ob->oargs.farg[3]sqrt(1.01-r3r3);
508			for (j = 0; j < 3; j++) {
509			org[j] = ob->oargs.farg[j] + r1u[j] + r2v[j] +
510			r3*dir[j];
511			dir[j] = -dir[j];
512			}
513	greg	1.2	/* send sample */
514	greg	2.18	raysamp(dim[1]*nazi+dim[2], org, dir);
515	greg	1.2	}
516	greg	2.25	/* wait for all rays to finish */
517	greg	2.18	rayclean();
518	greg	1.11	/* write out the sphere and its distribution */
519	greg	2.21	if (average(il, distarr, n)) {
520	greg	1.12	if (il->sampdens > 0)
521			roundout(il, distarr, nalt, nazi);
522			else
523			objerror(ob, WARNING, "diffuse distribution");
524			illumout(il, ob);
525	greg	2.2	} else
526	greg	1.12	printobj(il->altmat, ob);
527	greg	1.2	/* clean up */
528	greg	2.13	return(1);
529	greg	1.2	}
530
531
532	greg	2.13	int
533	greg	2.18	my_ring( /* make an illum ring */
534	schorsch	2.12	OBJREC *ob,
535			struct illum_args *il,
536			char *nm
537			)
538	greg	1.2	{
539	greg	2.21	int dim[2];
540			int n, nalt, nazi, alti;
541			double sp[2], r1, r2, r3;
542			int h;
543	greg	1.4	FVECT dn, org, dir;
544	greg	1.3	FVECT u, v;
545	greg	2.21	MAT4 xfm;
546			CONE *co;
547	greg	2.25	int i, j;
548	greg	1.3	/* get/check arguments */
549			co = getcone(ob, 0);
550			/* set up sampling */
551	greg	2.21	if (il->sd != NULL) {
552			if (!getBSDF_xfm(xfm, co->ad, il->udir)) {
553			objerror(ob, WARNING, "illegal up direction");
554			freecone(ob);
555			return(my_default(ob, il, nm));
556			}
557			n = il->sd->ninc;
558	greg	2.22	} else {
559			if (il->sampdens <= 0) {
560			nalt = nazi = 1; /* diffuse assumption */
561			} else {
562			n = PI * il->sampdens;
563			nalt = sqrt(n/PI) + .5;
564			nazi = PI*nalt + .5;
565			}
566	greg	2.21	n = nazi*nalt;
567	greg	2.22	}
568	greg	2.18	newdist(n);
569	greg	1.3	mkaxes(u, v, co->ad);
570			dim[0] = random();
571			/* sample disk */
572	greg	2.21	for (dim[1] = 0; dim[1] < n; dim[1]++)
573	greg	1.3	for (i = 0; i < il->nsamps; i++) {
574	greg	1.10	/* next sample point */
575	greg	2.21	h = ilhash(dim,2) + i;
576	greg	2.23	/* randomize direction */
577	greg	2.21	if (il->sd != NULL) {
578			r_BSDF_incvec(dir, il->sd, dim[1], urand(h), xfm);
579			} else {
580			multisamp(sp, 2, urand(h));
581			alti = dim[1]/nazi;
582			r1 = (alti + sp[0])/nalt;
583			r2 = (dim[1] - alti*nazi + sp[1] - .5)/nazi;
584			flatdir(dn, r1, r2);
585			for (j = 0; j < 3; j++)
586	greg	2.24	dir[j] = -dn[0]u[j] - dn[1]v[j] - dn[2]*co->ad[j];
587	greg	2.21	}
588	greg	2.23	/* randomize location */
589	greg	2.21	multisamp(sp, 2, urand(h+8371));
590	greg	1.5	r3 = sqrt(CO_R0(co)*CO_R0(co) +
591	greg	2.21	sp[0](CO_R1(co)CO_R1(co) - CO_R0(co)*CO_R0(co)));
592			r2 = 2.PIsp[1];
593	greg	1.5	r1 = r3*cos(r2);
594			r2 = r3*sin(r2);
595	greg	2.21	if (il->sd != NULL && DOT(dir, co->ad) < -FTINY)
596	greg	2.25	r3 = -1.0001il->thick - 5.FTINY;
597	greg	2.21	else
598	greg	2.25	r3 = 5.*FTINY;
599	greg	1.3	for (j = 0; j < 3; j++)
600	greg	2.6	org[j] = CO_P0(co)[j] + r1u[j] + r2v[j] +
601	greg	2.21	r3*co->ad[j];
602	greg	1.3	/* send sample */
603	greg	2.21	raysamp(dim[1], org, dir);
604	greg	1.3	}
605	greg	2.25	/* add in direct component? */
606	greg	2.29	if (!directvis && (il->flags & IL_LIGHT \|\| il->sd != NULL)) {
607	greg	2.25	MAT4 ixfm;
608			if (il->sd == NULL) {
609			for (i = 3; i--; ) {
610			ixfm[i][0] = u[i];
611			ixfm[i][1] = v[i];
612			ixfm[i][2] = co->ad[i];
613			ixfm[i][3] = 0.;
614			}
615			ixfm[3][0] = ixfm[3][1] = ixfm[3][2] = 0.;
616			ixfm[3][3] = 1.;
617	greg	2.29	} else {
618			if (!invmat4(ixfm, xfm))
619			objerror(ob, INTERNAL,
620			"cannot invert BSDF transform");
621			if (!(il->flags & IL_LIGHT))
622			new_discount();
623			}
624	greg	2.25	dim[0] = random();
625			for (i = 0; i < il->nsamps; i++) {
626			/* randomize location */
627			h = dim[0] + samplendx++;
628			multisamp(sp, 2, urand(h));
629			r3 = sqrt(CO_R0(co)*CO_R0(co) +
630			sp[0](CO_R1(co)CO_R1(co) - CO_R0(co)*CO_R0(co)));
631			r2 = 2.PIsp[1];
632			r1 = r3*cos(r2);
633			r2 = r3*sin(r2);
634			for (j = 0; j < 3; j++)
635			org[j] = CO_P0(co)[j] + r1u[j] + r2v[j];
636			/* sample source rays */
637			srcsamps(il, org, co->ad, ixfm);
638			}
639			}
640			/* wait for all rays to finish */
641	greg	2.18	rayclean();
642	greg	2.22	if (il->sd != NULL) { /* run distribution through BSDF */
643			nalt = sqrt(il->sd->nout/PI) + .5;
644			nazi = PI*nalt + .5;
645	greg	2.21	redistribute(il->sd, nalt, nazi, u, v, co->ad, xfm);
646	greg	2.29	done_discount();
647	greg	2.28	if (!il->sampdens)
648			il->sampdens = nalt*nazi/PI + .999;
649	greg	2.22	}
650	greg	1.11	/* write out the ring and its distribution */
651	greg	2.21	if (average(il, distarr, n)) {
652	greg	1.12	if (il->sampdens > 0)
653			flatout(il, distarr, nalt, nazi, u, v, co->ad);
654			illumout(il, ob);
655	greg	2.2	} else
656	greg	1.12	printobj(il->altmat, ob);
657	greg	1.3	/* clean up */
658			freecone(ob);
659	greg	2.13	return(1);
660	greg	1.2	}
661	greg	2.31
662
663			void
664			redistribute( /* pass distarr ray sums through BSDF */
665			struct BSDF_data *b,
666			int nalt,
667			int nazi,
668			FVECT u,
669			FVECT v,
670			FVECT w,
671			MAT4 xm
672			)
673			{
674			int nout = 0;
675			MAT4 mymat, inmat;
676			COLORV *idist;
677			COLORV *cp;
678			FVECT dv;
679			double wt;
680			int i, j, k, c, o;
681			COLOR col, cinc;
682			/* copy incoming distribution */
683			if (b->ninc > distsiz)
684			error(INTERNAL, "error 1 in redistribute");
685			idist = (COLORV )malloc(sizeof(COLOR)b->ninc);
686			if (idist == NULL)
687			error(SYSTEM, "out of memory in redistribute");
688			memcpy(idist, distarr, sizeof(COLOR)*b->ninc);
689			/* compose direction transform */
690			for (i = 3; i--; ) {
691			mymat[i][0] = u[i];
692			mymat[i][1] = v[i];
693			mymat[i][2] = w[i];
694			mymat[i][3] = 0.;
695			}
696			mymat[3][0] = mymat[3][1] = mymat[3][2] = 0.;
697			mymat[3][3] = 1.;
698			if (xm != NULL)
699			multmat4(mymat, xm, mymat);
700			for (i = 3; i--; ) { /* make sure it's normalized */
701			wt = 1./sqrt( mymat[0][i]*mymat[0][i] +
702			mymat[1][i]*mymat[1][i] +
703			mymat[2][i]*mymat[2][i] );
704			for (j = 3; j--; )
705			mymat[j][i] *= wt;
706			}
707			if (!invmat4(inmat, mymat)) /* need inverse as well */
708			error(INTERNAL, "cannot invert BSDF transform");
709			newdist(naltnazi); / resample distribution */
710			for (i = b->ninc; i--; ) {
711			int direct_out = -1;
712			COLOR cdir;
713			getBSDF_incvec(dv, b, i); /* compute incident irrad. */
714			multv3(dv, dv, mymat);
715			if (dv[2] < 0.0) {
716			dv[0] = -dv[0]; dv[1] = -dv[1]; dv[2] = -dv[2];
717			direct_out += (direct_discount != NULL);
718			}
719			wt = getBSDF_incohm(b, i);
720			wt = dv[2]; / solid_anglecosine(theta) /
721			cp = &idist[3*i];
722			copycolor(cinc, cp);
723			scalecolor(cinc, wt);
724			if (!direct_out) { /* discount direct contr. */
725			cp = &direct_discount[3*i];
726			copycolor(cdir, cp);
727			scalecolor(cdir, -wt);
728	greg	2.33	if (b->nout != b->ninc)
729			direct_out = flatindex(dv, nalt, nazi);
730			else
731			direct_out = i; /* assumes dist. mirroring */
732	greg	2.31	}
733			for (k = nalt; k--; ) /* loop over distribution */
734			for (j = nazi; j--; ) {
735			int rstart = random();
736			for (c = NBSDFSAMPS; c--; ) {
737			double sp[2];
738			multisamp(sp, 2, urand(rstart+c));
739			flatdir(dv, (k + sp[0])/nalt,
740			(j + .5 - sp[1])/nazi);
741			multv3(dv, dv, inmat);
742			/* evaluate BSDF @ outgoing */
743			o = getBSDF_outndx(b, dv);
744			if (o < 0) {
745			nout++;
746			continue;
747			}
748			wt = BSDF_value(b, i, o) * (1./NBSDFSAMPS);
749			copycolor(col, cinc);
750	greg	2.33	if (b->nout != b->ninc)
751			o = k*nazi + j;
752	greg	2.31	if (o == direct_out)
753			addcolor(col, cdir); /* minus direct */
754			scalecolor(col, wt);
755	greg	2.34	cp = &distarr[3(knazi + j)];
756	greg	2.31	addcolor(cp, col); /* sum into distribution */
757			}
758			}
759			}
760			free(idist); /* free temp space */
761			if (nout) {
762			sprintf(errmsg, "missing %.1f%% of BSDF directions",
763			100.nout/(b->nincnaltnaziNBSDFSAMPS));
764			error(WARNING, errmsg);
765			}
766			}