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);
}
void
xf_xfmpoint(FVECT v1, FVECT v2) /* transform a point by the current matrix */
{
if (xf_context == NULL) {
VCOPY(v1, v2);
return;
}
multp3(v1, v2, xf_context->xf.xfm);
}
static int
o_cube( /* determine if cubes intersect */
CUBE *cu1,
FULLXF *fxf,
CUBE *cu
)
{
static int vstart[4] = {0, 3, 5, 6};
FVECT cumin, cumax;
FVECT vert[8];
FVECT v1, v2;
int vloc, vout;
register int i, j;
/* check if cube vertex in octree */
for (j = 0; j < 3; j++)
cumax[j] = (cumin[j] = cu1->cuorg[j]) + cu1->cusize;
vloc = ABOVE | BELOW;
vout = 0;
for (i = 0; i < 8; i++) {
for (j = 0; j < 3; j++) {
v1[j] = cu->cuorg[j];
if (i & 1<<j)
v1[j] += cu->cusize;
}
multp3(v2, v1, fxf->b.xfm);
if ( (j = plocate(v2, cumin, cumax)) )
vout++;
vloc &= j;
}
if (vout == 0) /* all inside */
return(O_IN);
if (vout < 8) /* some inside */
return(O_HIT);
if (vloc) /* all to one side */
return(O_MISS);
/* octree vertices in cube? */
for (j = 0; j < 3; j++)
cumax[j] = (cumin[j] = cu->cuorg[j]) + cu->cusize;
vloc = ABOVE | BELOW;
for (i = 0; i < 8; i++) {
for (j = 0; j < 3; j++) {
v1[j] = cu1->cuorg[j];
if (i & 1<<j)
v1[j] += cu1->cusize;
}
multp3(vert[i], v1, fxf->f.xfm);
if ( (j = plocate(vert[i], cumin, cumax)) )
vloc &= j;
else
return(O_HIT); /* vertex inside */
}
if (vloc) /* all to one side */
return(O_MISS);
/* check edges */
for (i = 0; i < 4; i++)
for (j = 0; j < 3; j++) {
/* clip modifies vertices! */
VCOPY(v1, vert[vstart[i]]);
VCOPY(v2, vert[vstart[i] ^ 1<<j]);
if (clip(v1, v2, cumin, cumax))
return(O_HIT); /* edge inside */
}
return(O_MISS); /* no intersection */
}
void
add2bbox( /* expand bounding box to fit object */
register OBJREC *o,
FVECT bbmin,
FVECT bbmax
)
{
CONE *co;
FACE *fo;
INSTANCE *io;
MESHINST *mi;
FVECT v;
register int i, j;
switch (o->otype) {
case OBJ_SPHERE:
case OBJ_BUBBLE:
if (o->oargs.nfargs != 4)
objerror(o, USER, "bad arguments");
for (i = 0; i < 3; i++) {
VCOPY(v, o->oargs.farg);
v[i] -= o->oargs.farg[3];
point2bbox(v, bbmin, bbmax);
v[i] += 2.0 * o->oargs.farg[3];
point2bbox(v, bbmin, bbmax);
}
break;
case OBJ_FACE:
fo = getface(o);
j = fo->nv;
while (j--)
point2bbox(VERTEX(fo,j), bbmin, bbmax);
break;
case OBJ_CONE:
case OBJ_CUP:
case OBJ_CYLINDER:
case OBJ_TUBE:
case OBJ_RING:
co = getcone(o, 0);
if (o->otype != OBJ_RING)
circle2bbox(CO_P0(co), co->ad, CO_R0(co), bbmin, bbmax);
circle2bbox(CO_P1(co), co->ad, CO_R1(co), bbmin, bbmax);
break;
case OBJ_INSTANCE:
io = getinstance(o, IO_BOUNDS);
for (j = 0; j < 8; j++) {
for (i = 0; i < 3; i++) {
v[i] = io->obj->scube.cuorg[i];
if (j & 1<<i)
v[i] += io->obj->scube.cusize;
}
multp3(v, v, io->x.f.xfm);
point2bbox(v, bbmin, bbmax);
}
break;
case OBJ_MESH:
mi = getmeshinst(o, IO_BOUNDS);
for (j = 0; j < 8; j++) {
for (i = 0; i < 3; i++) {
v[i] = mi->msh->mcube.cuorg[i];
if (j & 1<<i)
v[i] += mi->msh->mcube.cusize;
}
multp3(v, v, mi->x.f.xfm);
point2bbox(v, bbmin, bbmax);
}
break;
}
}
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);
}
