extern int
o_cone( /* determine if cone intersects cube */
OBJREC *o,
register CUBE *cu
)
{
CONE *co;
FVECT ep0, ep1;
#ifdef STRICT
FVECT cumin, cumax;
CUBE cukid;
register int j;
#endif
double r;
FVECT p;
register int i;
/* get cone arguments */
co = getcone(o, 0);
/* get cube center */
r = cu->cusize * 0.5;
for (i = 0; i < 3; i++)
p[i] = cu->cuorg[i] + r;
r *= ROOT3; /* bounding radius for cube */
if (findcseg(ep0, ep1, co, p)) {
/* check min. distance to cone */
if (dist2lseg(p, ep0, ep1) > (r+FTINY)*(r+FTINY))
return(O_MISS);
#ifdef STRICT
/* get cube boundaries */
for (i = 0; i < 3; i++)
cumax[i] = (cumin[i] = cu->cuorg[i]) + cu->cusize;
/* closest segment intersects? */
if (clip(ep0, ep1, cumin, cumax))
return(O_HIT);
}
/* check sub-cubes */
cukid.cusize = cu->cusize * 0.5;
if (cukid.cusize < mincusize)
return(O_HIT); /* cube too small */
cukid.cutree = EMPTY;
for (j = 0; j < 8; j++) {
for (i = 0; i < 3; i++) {
cukid.cuorg[i] = cu->cuorg[i];
if (1<<i & j)
cukid.cuorg[i] += cukid.cusize;
}
if (o_cone(o, &cukid))
return(O_HIT); /* sub-cube intersects */
}
return(O_MISS); /* no intersection */
#else
}
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);
}
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;
}
}
extern int
load_os( /* load associated data for object */
register OBJREC *op
)
{
DATARRAY *dp;
switch (op->otype) {
case OBJ_FACE: /* polygon */
getface(op);
return(1);
case OBJ_CONE: /* cone */
case OBJ_RING: /* disk */
case OBJ_CYLINDER: /* cylinder */
case OBJ_CUP: /* inverted cone */
case OBJ_TUBE: /* inverted cylinder */
getcone(op, 1);
return(1);
case OBJ_INSTANCE: /* octree instance */
getinstance(op, IO_ALL);
return(1);
case OBJ_MESH: /* mesh instance */
getmeshinst(op, IO_ALL);
return(1);
case PAT_CPICT: /* color picture */
if (op->oargs.nsargs < 4)
goto sargerr;
getpict(op->oargs.sarg[3]);
getfunc(op, 4, 0x3<<5, 0);
return(1);
case PAT_CDATA: /* color data */
dp = getdata(op->oargs.sarg[3]);
getdata(op->oargs.sarg[4]);
getdata(op->oargs.sarg[5]);
getfunc(op, 6, ((1<<dp->nd)-1)<<7, 0);
return(1);
case PAT_BDATA: /* brightness data */
if (op->oargs.nsargs < 2)
goto sargerr;
dp = getdata(op->oargs.sarg[1]);
getfunc(op, 2, ((1<<dp->nd)-1)<<3, 0);
return(1);
case PAT_BFUNC: /* brightness function */
getfunc(op, 1, 0x1, 0);
return(1);
case PAT_CFUNC: /* color function */
getfunc(op, 3, 0x7, 0);
return(1);
case TEX_DATA: /* texture data */
if (op->oargs.nsargs < 6)
goto sargerr;
dp = getdata(op->oargs.sarg[3]);
getdata(op->oargs.sarg[4]);
getdata(op->oargs.sarg[5]);
getfunc(op, 6, ((1<<dp->nd)-1)<<7, 1);
return(1);
case TEX_FUNC: /* texture function */
getfunc(op, 3, 0x7, 1);
return(1);
case MIX_DATA: /* mixture data */
dp = getdata(op->oargs.sarg[3]);
getfunc(op, 4, ((1<<dp->nd)-1)<<5, 0);
return(1);
case MIX_PICT: /* mixture picture */
getpict(op->oargs.sarg[3]);
getfunc(op, 4, 0x3<<5, 0);
return(1);
case MIX_FUNC: /* mixture function */
getfunc(op, 3, 0x4, 0);
return(1);
case MAT_PLASTIC2: /* anisotropic plastic */
case MAT_METAL2: /* anisotropic metal */
getfunc(op, 3, 0x7, 1);
return(1);
case MAT_BRTDF: /* BRDTfunc material */
getfunc(op, 9, 0x3f, 0);
return(1);
case MAT_BSDF: /* BSDF material */
if (op->oargs.nsargs < 6)
goto sargerr;
getfunc(op, 5, 0x1d, 1);
loadBSDF(op->oargs.sarg[1]);
return(1);
case MAT_PDATA: /* plastic BRDF data */
case MAT_MDATA: /* metal BRDF data */
case MAT_TDATA: /* trans BRDF data */
if (op->oargs.nsargs < 2)
goto sargerr;
getdata(op->oargs.sarg[1]);
getfunc(op, 2, 0, 0);
return(1);
case MAT_PFUNC: /* plastic BRDF func */
case MAT_MFUNC: /* metal BRDF func */
case MAT_TFUNC: /* trans BRDF func */
getfunc(op, 1, 0, 0);
return(1);
case MAT_DIRECT1: /* prism1 material */
getfunc(op, 4, 0xf, 1);
return(1);
case MAT_DIRECT2: /* prism2 material */
getfunc(op, 8, 0xff, 1);
return(1);
}
/* nothing to load for the remaining types */
return(0);
sargerr:
objerror(op, USER, "too few string arguments");
return 0; /* pro forma return */
}
