int
t_func( /* compute texture for ray */
OBJREC *m,
RAY *r
)
{
FVECT disp;
double d;
MFUNC *mf;
int i;
if (m->oargs.nsargs < 4)
objerror(m, USER, "bad # arguments");
mf = getfunc(m, 3, 0x7, 1);
setfunc(m, r);
errno = 0;
for (i = 0; i < 3; i++) {
disp[i] = evalue(mf->ep[i]);
if (errno == EDOM || errno == ERANGE) {
objerror(m, WARNING, "compute error");
return(0);
}
}
if (mf->fxp != &unitxf)
multv3(disp, disp, mf->fxp->xfm);
if (r->rox != NULL) {
multv3(disp, disp, r->rox->f.xfm);
d = 1.0 / (mf->fxp->sca * r->rox->f.sca);
} else
d = 1.0 / mf->fxp->sca;
VSUM(r->pert, r->pert, disp, d);
return(0);
}
extern int
o_instance( /* compute ray intersection with octree */
OBJREC *o,
register RAY *r
)
{
RAY rcont;
double d;
register INSTANCE *ins;
register int i;
/* get the octree */
ins = getinstance(o, IO_ALL);
/* copy and transform ray */
rcont = *r;
multp3(rcont.rorg, r->rorg, ins->x.b.xfm);
multv3(rcont.rdir, r->rdir, ins->x.b.xfm);
for (i = 0; i < 3; i++)
rcont.rdir[i] /= ins->x.b.sca;
rcont.rmax *= ins->x.b.sca;
/* clear and trace it */
rayclear(&rcont);
if (!localhit(&rcont, &ins->obj->scube))
return(0); /* missed */
if (rcont.rot * ins->x.f.sca >= r->rot)
return(0); /* not close enough */
if (o->omod != OVOID) { /* if we have modifier, use it */
r->ro = o;
r->rox = NULL;
} else { /* else use theirs */
r->ro = rcont.ro;
if (rcont.rox != NULL) {
newrayxf(r); /* allocate transformation */
/* NOTE: r->rox may equal rcont.rox! */
multmat4(r->rox->f.xfm, rcont.rox->f.xfm, ins->x.f.xfm);
r->rox->f.sca = rcont.rox->f.sca * ins->x.f.sca;
multmat4(r->rox->b.xfm, ins->x.b.xfm, rcont.rox->b.xfm);
r->rox->b.sca = ins->x.b.sca * rcont.rox->b.sca;
} else
r->rox = &ins->x;
}
/* transform it back */
r->rot = rcont.rot * ins->x.f.sca;
multp3(r->rop, rcont.rop, ins->x.f.xfm);
multv3(r->ron, rcont.ron, ins->x.f.xfm);
multv3(r->pert, rcont.pert, ins->x.f.xfm);
d = 1./ins->x.f.sca;
for (i = 0; i < 3; i++) {
r->ron[i] *= d;
r->pert[i] *= d;
}
r->rod = rcont.rod;
r->uv[0] = rcont.uv[0];
r->uv[1] = rcont.uv[1];
/* return hit */
return(1);
}
static void
getacoords_as( /* set up coordinate system */
ASHIKDAT *np
)
{
MFUNC *mf;
int i;
mf = getfunc(np->mp, 3, 0x7, 1);
setfunc(np->mp, np->rp);
errno = 0;
for (i = 0; i < 3; i++)
np->u[i] = evalue(mf->ep[i]);
if ((errno == EDOM) | (errno == ERANGE)) {
objerror(np->mp, WARNING, "compute error");
np->specfl |= SPA_BADU;
return;
}
if (mf->fxp != &unitxf)
multv3(np->u, np->u, mf->fxp->xfm);
fcross(np->v, np->pnorm, np->u);
if (normalize(np->v) == 0.0) {
objerror(np->mp, WARNING, "illegal orientation vector");
np->specfl |= SPA_BADU;
return;
}
fcross(np->u, np->v, np->pnorm);
}
static void
getacoords( /* set up coordinate system */
ANISODAT *np
)
{
MFUNC *mf;
int i;
mf = getfunc(np->mp, 3, 0x7, 1);
setfunc(np->mp, np->rp);
errno = 0;
for (i = 0; i < 3; i++)
np->u[i] = evalue(mf->ep[i]);
if ((errno == EDOM) | (errno == ERANGE))
np->u[0] = np->u[1] = np->u[2] = 0.0;
if (mf->fxp != &unitxf)
multv3(np->u, np->u, mf->fxp->xfm);
fcross(np->v, np->pnorm, np->u);
if (normalize(np->v) == 0.0) {
if (fabs(np->u_alpha - np->v_alpha) > 0.001)
objerror(np->mp, WARNING, "illegal orientation vector");
getperpendicular(np->u, np->pnorm); /* punting */
fcross(np->v, np->pnorm, np->u);
np->u_alpha = np->v_alpha = sqrt( 0.5 *
(np->u_alpha*np->u_alpha + np->v_alpha*np->v_alpha) );
} else
fcross(np->u, np->v, np->pnorm);
}
void
xf_xfmvect(FVECT v1, FVECT v2) /* transform a vector using current matrix */
{
if (xf_context == NULL) {
VCOPY(v1, v2);
return;
}
multv3(v1, v2, xf_context->xf.xfm);
}
static int
setbrdfunc( /* set up brdf function and variables */
BRDFDAT *np
)
{
FVECT vec;
if (setfunc(np->mp, np->pr) == 0)
return(0); /* it's OK, setfunc says we're done */
/* else (re)assign special variables */
multv3(vec, np->pnorm, funcxf.xfm);
varset("NxP", '=', vec[0]/funcxf.sca);
varset("NyP", '=', vec[1]/funcxf.sca);
varset("NzP", '=', vec[2]/funcxf.sca);
varset("RdotP", '=', np->pdot <= -1.0 ? -1.0 :
np->pdot >= 1.0 ? 1.0 : np->pdot);
varset("CrP", '=', colval(np->mcolor,RED));
varset("CgP", '=', colval(np->mcolor,GRN));
varset("CbP", '=', colval(np->mcolor,BLU));
return(1);
}
static void
dirbrdf( /* compute source contribution */
COLOR cval, /* returned coefficient */
void *nnp, /* material data */
FVECT ldir, /* light source direction */
double omega /* light source size */
)
{
BRDFDAT *np = nnp;
double ldot;
double dtmp;
COLOR ctmp;
FVECT ldx;
static double vldx[5], pt[MAXDIM];
char **sa;
int i;
#define lddx (vldx+1)
setcolor(cval, 0.0, 0.0, 0.0);
ldot = DOT(np->pnorm, ldir);
if (ldot <= FTINY && ldot >= -FTINY)
return; /* too close to grazing */
if (ldot < 0.0 ? np->trans <= FTINY : np->trans >= 1.0-FTINY)
return; /* wrong side */
if (ldot > 0.0) {
/*
* Compute and add diffuse reflected component to returned
* color. The diffuse reflected component will always be
* modified by the color of the material.
*/
copycolor(ctmp, np->rdiff);
dtmp = ldot * omega / PI;
scalecolor(ctmp, dtmp);
addcolor(cval, ctmp);
} else {
/*
* Diffuse transmitted component.
*/
copycolor(ctmp, np->tdiff);
dtmp = -ldot * omega / PI;
scalecolor(ctmp, dtmp);
addcolor(cval, ctmp);
}
if (ldot > 0.0 ? np->rspec <= FTINY : np->tspec <= FTINY)
return; /* diffuse only */
/* set up function */
setbrdfunc(np);
sa = np->mp->oargs.sarg;
errno = 0;
/* transform light vector */
multv3(ldx, ldir, funcxf.xfm);
for (i = 0; i < 3; i++)
lddx[i] = ldx[i]/funcxf.sca;
lddx[3] = omega;
/* compute BRTDF */
if (np->mp->otype == MAT_BRTDF) {
if (sa[6][0] == '0') /* special case */
colval(ctmp,RED) = 0.0;
else
colval(ctmp,RED) = funvalue(sa[6], 4, lddx);
if (sa[7][0] == '0')
colval(ctmp,GRN) = 0.0;
else if (!strcmp(sa[7],sa[6]))
colval(ctmp,GRN) = colval(ctmp,RED);
else
colval(ctmp,GRN) = funvalue(sa[7], 4, lddx);
if (!strcmp(sa[8],sa[6]))
colval(ctmp,BLU) = colval(ctmp,RED);
else if (!strcmp(sa[8],sa[7]))
colval(ctmp,BLU) = colval(ctmp,GRN);
else
colval(ctmp,BLU) = funvalue(sa[8], 4, lddx);
dtmp = bright(ctmp);
} else if (np->dp == NULL) {
dtmp = funvalue(sa[0], 4, lddx);
setcolor(ctmp, dtmp, dtmp, dtmp);
} else {
for (i = 0; i < np->dp->nd; i++)
pt[i] = funvalue(sa[3+i], 4, lddx);
vldx[0] = datavalue(np->dp, pt);
dtmp = funvalue(sa[0], 5, vldx);
setcolor(ctmp, dtmp, dtmp, dtmp);
}
if ((errno == EDOM) | (errno == ERANGE)) {
objerror(np->mp, WARNING, "compute error");
return;
}
if (dtmp <= FTINY)
return;
if (ldot > 0.0) {
/*
* Compute reflected non-diffuse component.
*/
if ((np->mp->otype == MAT_MFUNC) | (np->mp->otype == MAT_MDATA))
multcolor(ctmp, np->mcolor);
dtmp = ldot * omega * np->rspec;
scalecolor(ctmp, dtmp);
addcolor(cval, ctmp);
} else {
/*
* Compute transmitted non-diffuse component.
*/
if ((np->mp->otype == MAT_TFUNC) | (np->mp->otype == MAT_TDATA))
multcolor(ctmp, np->mcolor);
dtmp = -ldot * omega * np->tspec;
scalecolor(ctmp, dtmp);
addcolor(cval, ctmp);
}
#undef lddx
}
int
o_cone( /* intersect ray with cone */
OBJREC *o,
RAY *r
)
{
FVECT rox, rdx;
double a, b, c;
double root[2];
int nroots, rn;
CONE *co;
int i;
/* get cone structure */
co = getcone(o, 1);
/*
* To intersect a ray with a cone, we transform the
* ray into the cone's normalized space. This greatly
* simplifies the computation.
* For a cone or cup, normalization results in the
* equation:
*
* x*x + y*y - z*z == 0
*
* For a cylinder or tube, the normalized equation is:
*
* x*x + y*y - r*r == 0
*
* A normalized ring obeys the following set of equations:
*
* z == 0 &&
* x*x + y*y >= r0*r0 &&
* x*x + y*y <= r1*r1
*/
/* transform ray */
multp3(rox, r->rorg, co->tm);
multv3(rdx, r->rdir, co->tm);
/* compute intersection */
if (o->otype == OBJ_CONE || o->otype == OBJ_CUP) {
a = rdx[0]*rdx[0] + rdx[1]*rdx[1] - rdx[2]*rdx[2];
b = 2.0*(rdx[0]*rox[0] + rdx[1]*rox[1] - rdx[2]*rox[2]);
c = rox[0]*rox[0] + rox[1]*rox[1] - rox[2]*rox[2];
} else if (o->otype == OBJ_CYLINDER || o->otype == OBJ_TUBE) {
a = rdx[0]*rdx[0] + rdx[1]*rdx[1];
b = 2.0*(rdx[0]*rox[0] + rdx[1]*rox[1]);
c = rox[0]*rox[0] + rox[1]*rox[1] - CO_R0(co)*CO_R0(co);
} else { /* OBJ_RING */
if (rdx[2] <= FTINY && rdx[2] >= -FTINY)
return(0); /* parallel */
root[0] = -rox[2]/rdx[2];
if (root[0] <= FTINY || root[0] >= r->rot)
return(0); /* distance check */
b = root[0]*rdx[0] + rox[0];
c = root[0]*rdx[1] + rox[1];
a = b*b + c*c;
if (a < CO_R0(co)*CO_R0(co) || a > CO_R1(co)*CO_R1(co))
return(0); /* outside radii */
r->ro = o;
r->rot = root[0];
VSUM(r->rop, r->rorg, r->rdir, r->rot);
VCOPY(r->ron, co->ad);
r->rod = -rdx[2];
r->rox = NULL;
return(1); /* good */
}
/* roots for cone, cup, cyl., tube */
nroots = quadratic(root, a, b, c);
for (rn = 0; rn < nroots; rn++) { /* check real roots */
if (root[rn] <= FTINY)
continue; /* too small */
if (root[rn] >= r->rot)
break; /* too big */
/* check endpoints */
VSUM(rox, r->rorg, r->rdir, root[rn]);
VSUB(rdx, rox, CO_P0(co));
b = DOT(rdx, co->ad);
if (b < 0.0)
continue; /* before p0 */
if (b > co->al)
continue; /* after p1 */
r->ro = o;
r->rot = root[rn];
VCOPY(r->rop, rox);
/* get normal */
if (o->otype == OBJ_CYLINDER)
a = CO_R0(co);
else if (o->otype == OBJ_TUBE)
a = -CO_R0(co);
else { /* OBJ_CONE || OBJ_CUP */
c = CO_R1(co) - CO_R0(co);
a = CO_R0(co) + b*c/co->al;
if (o->otype == OBJ_CUP) {
c = -c;
a = -a;
}
}
for (i = 0; i < 3; i++)
r->ron[i] = (rdx[i] - b*co->ad[i])/a;
if (o->otype == OBJ_CONE || o->otype == OBJ_CUP)
for (i = 0; i < 3; i++)
r->ron[i] = (co->al*r->ron[i] - c*co->ad[i])
/ co->sl;
a = DOT(r->ron, r->ron);
if (a > 1.+FTINY || a < 1.-FTINY) {
c = 1./(.5 + .5*a); /* avoid numerical error */
r->ron[0] *= c; r->ron[1] *= c; r->ron[2] *= c;
}
r->rod = -DOT(r->rdir, r->ron);
r->pert[0] = r->pert[1] = r->pert[2] = 0.0;
r->uv[0] = r->uv[1] = 0.0;
r->rox = NULL;
return(1); /* good */
}
return(0);
}
static int
redirect( /* compute n'th ray redirection */
OBJREC *m,
RAY *r,
int n
)
{
MFUNC *mf;
EPNODE **va;
FVECT nsdir;
RAY nr;
double coef;
int j;
/* set up function */
mf = getdfunc(m);
setfunc(m, r);
/* assign direction variable */
if (r->rsrc >= 0) {
SRCREC *sp = source + source[r->rsrc].sa.sv.sn;
if (sp->sflags & SDISTANT)
VCOPY(nsdir, sp->sloc);
else {
for (j = 0; j < 3; j++)
nsdir[j] = sp->sloc[j] - r->rop[j];
normalize(nsdir);
}
multv3(nsdir, nsdir, funcxf.xfm);
varset("DxA", '=', nsdir[0]/funcxf.sca);
varset("DyA", '=', nsdir[1]/funcxf.sca);
varset("DzA", '=', nsdir[2]/funcxf.sca);
} else {
varset("DxA", '=', 0.0);
varset("DyA", '=', 0.0);
varset("DzA", '=', 0.0);
}
/* compute coefficient */
errno = 0;
va = mf->ep + 4*n;
coef = evalue(va[0]);
if ((errno == EDOM) | (errno == ERANGE))
goto computerr;
setcolor(nr.rcoef, coef, coef, coef);
if (rayorigin(&nr, TRANS, r, nr.rcoef) < 0)
return(0);
va++; /* compute direction */
for (j = 0; j < 3; j++) {
nr.rdir[j] = evalue(va[j]);
if (errno == EDOM || errno == ERANGE)
goto computerr;
}
if (mf->fxp != &unitxf)
multv3(nr.rdir, nr.rdir, mf->fxp->xfm);
if (r->rox != NULL)
multv3(nr.rdir, nr.rdir, r->rox->f.xfm);
if (normalize(nr.rdir) == 0.0)
goto computerr;
/* compute value */
if (r->rsrc >= 0)
nr.rsrc = source[r->rsrc].sa.sv.sn;
rayvalue(&nr);
multcolor(nr.rcol, nr.rcoef);
addcolor(r->rcol, nr.rcol);
if (r->ro != NULL && isflat(r->ro->otype))
r->rt = r->rot + nr.rt;
return(1);
computerr:
objerror(m, WARNING, "compute error");
return(-1);
}
static int
dir_proj( /* compute a director's projection */
MAT4 pm,
OBJREC *o,
SRCREC *s,
int n
)
{
RAY tr;
OBJREC *m;
MFUNC *mf;
EPNODE **va;
FVECT cent, newdir, nv, h;
double coef, olddot, newdot, od;
int i, j;
/* initialize test ray */
getmaxdisk(cent, o);
if (s->sflags & SDISTANT)
for (i = 0; i < 3; i++) {
tr.rdir[i] = -s->sloc[i];
tr.rorg[i] = cent[i] - tr.rdir[i];
}
else {
for (i = 0; i < 3; i++) {
tr.rdir[i] = cent[i] - s->sloc[i];
tr.rorg[i] = s->sloc[i];
}
if (normalize(tr.rdir) == 0.0)
return(0); /* at source! */
}
od = getplaneq(nv, o);
olddot = DOT(tr.rdir, nv);
if (olddot <= FTINY && olddot >= -FTINY)
return(0); /* old dir parallels plane */
tr.rmax = 0.0;
rayorigin(&tr, PRIMARY, NULL, NULL);
if (!(*ofun[o->otype].funp)(o, &tr))
return(0); /* no intersection! */
/* compute redirection */
m = vsmaterial(o);
mf = getdfunc(m);
setfunc(m, &tr);
varset("DxA", '=', 0.0);
varset("DyA", '=', 0.0);
varset("DzA", '=', 0.0);
errno = 0;
va = mf->ep + 4*n;
coef = evalue(va[0]);
if (errno == EDOM || errno == ERANGE)
goto computerr;
if (coef <= FTINY)
return(0); /* insignificant */
va++;
for (i = 0; i < 3; i++) {
newdir[i] = evalue(va[i]);
if (errno == EDOM || errno == ERANGE)
goto computerr;
}
if (mf->fxp != &unitxf)
multv3(newdir, newdir, mf->fxp->xfm);
/* normalization unnecessary */
newdot = DOT(newdir, nv);
if (newdot <= FTINY && newdot >= -FTINY)
return(0); /* new dir parallels plane */
/* everything OK -- compute shear */
for (i = 0; i < 3; i++)
h[i] = newdir[i]/newdot - tr.rdir[i]/olddot;
setident4(pm);
for (j = 0; j < 3; j++) {
for (i = 0; i < 3; i++)
pm[i][j] += nv[i]*h[j];
pm[3][j] = -od*h[j];
}
if ((newdot > 0.0) ^ (olddot > 0.0)) /* add mirroring */
for (j = 0; j < 3; j++) {
for (i = 0; i < 3; i++)
pm[i][j] -= 2.*nv[i]*nv[j];
pm[3][j] += 2.*od*nv[j];
}
return(1);
computerr:
objerror(m, WARNING, "projection compute error");
return(0);
}
