int
o_face( /* determine if face intersects cube */
OBJREC *o,
CUBE *cu
)
{
FVECT cumin, cumax;
FVECT v1, v2;
double d1, d2;
int vloc;
register FACE *f;
register int i, j;
/* get face arguments */
f = getface(o);
if (f->area == 0.0) /* empty face */
return(O_MISS);
/* compute cube boundaries */
for (j = 0; j < 3; j++)
cumax[j] = (cumin[j] = cu->cuorg[j]-FTINY)
+ cu->cusize + 2.0*FTINY;
vloc = ABOVE | BELOW; /* check vertices */
for (i = 0; i < f->nv; i++)
if ( (j = plocate(VERTEX(f,i), cumin, cumax)) )
vloc &= j;
else
return(O_HIT); /* vertex inside */
if (vloc) /* all to one side */
return(O_MISS);
for (i = 0; i < f->nv; i++) { /* check edges */
if ((j = i + 1) >= f->nv)
j = 0; /* wrap around */
VCOPY(v1, VERTEX(f,i)); /* clip modifies */
VCOPY(v2, VERTEX(f,j)); /* the vertices! */
if (clip(v1, v2, cumin, cumax))
return(O_HIT); /* edge inside */
}
/* see if cube cuts plane */
for (j = 0; j < 3; j++)
if (f->norm[j] > 0.0) {
v1[j] = cumin[j];
v2[j] = cumax[j];
} else {
v1[j] = cumax[j];
v2[j] = cumin[j];
}
if ((d1 = DOT(v1, f->norm) - f->offset) > FTINY)
return(O_MISS);
if ((d2 = DOT(v2, f->norm) - f->offset) < -FTINY)
return(O_MISS);
/* intersect face */
for (j = 0; j < 3; j++)
v1[j] = (v1[j]*d2 - v2[j]*d1)/(d2 - d1);
if (inface(v1, f))
return(O_HIT);
return(O_MISS); /* no intersection */
}
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 */
}
