src/gen/mkillum2.c

#ifndef lint
static const char       RCSid[] = "$Id: mkillum2.c,v 2.35 2010/09/03 23:53:50 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"
#include  "paths.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(distarr);
                distarr = NULL;
                distsiz = 0;
                return;
        }
        if (distsiz < siz) {
                if (distsiz > 0)
                        free(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(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|SPECULAR, 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
printgeom(              /* print out detailed geometry for BSDF */
        struct BSDF_data *sd,
        char *xfrot,
        FVECT ctr,
        double s1,
        double s2
)
{
        static char     mgftemp[] = TEMPLATE;
        char            cmdbuf[64];
        FILE            *fp;
        double          sca;

        if (sd == NULL || sd->mgf == NULL)
                return(0);
        if (sd->dim[0] <= FTINY || sd->dim[1] <= FTINY)
                return(0);
        if ((s1 > s2) ^ (sd->dim[0] > sd->dim[1])) {
                sca = s1; s1 = s2; s2 = sca;
        }
        s1 /= sd->dim[0];
        s2 /= sd->dim[1];
        sca = s1 > s2 ? s1 : s2;
        strcpy(mgftemp, TEMPLATE);
        if ((fp = fopen(mktemp(mgftemp), "w")) == NULL)
                error(SYSTEM, "cannot create temporary file for MGF");
                                        /* prepend our transform */
        fprintf(fp, "xf%s -s %.5f -t %.5g %.5g %.5g\n",
                        xfrot, sca, ctr[0], ctr[1], ctr[2]);
                                        /* output given MGF description */
        fputs(sd->mgf, fp);
        fputs("\nxf\n", fp);
        if (fclose(fp) == EOF)
                error(SYSTEM, "error writing MGF temporary file");
                                        /* execute mgf2rad to convert MGF */
        strcpy(cmdbuf, "mgf2rad ");
        strcpy(cmdbuf+8, mgftemp);
        fflush(stdout);
        system(cmdbuf);
        unlink(mgftemp);                /* clean up */
        return(1);
}


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;
        char  xfrot[64];
        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, xfrot)) {
                        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;
        }
                                /* output detailed geometry? */
        if (!(il->flags & IL_LIGHT) && il->sd != NULL && il->sd->mgf != NULL &&
                        il->thick <= FTINY) {
                for (j = 3; j--; )
                        org[j] = .5*(ur[0]+ur[1])*u[j] +
                                        .5*(vr[0]+vr[1])*v[j] +
                                        fa->offset*fa->norm[j];
                printgeom(il->sd, xfrot, org, ur[1]-ur[0], vr[1]-vr[0]);
        }
        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 (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, NULL)) {
                        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 (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:	2.36
Committed:	Mon Aug 15 19:48:06 2011 UTC (12 years, 8 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.35:	+7 -7 lines
Log Message:	Made direct visibility (-dv) flag irrelevant and fixed BSDF material sampling