int Intersect_BCyl(BCYL *BCyl, VECTOR P, VECTOR D)
{
int i, cnt;
DBL dist[8];
BCYL_INT Inter;
BCYL_INT *intervals;
BCYL_ENTRY *Entry;
cnt = 0;
Inter.d[1] = 0.0;
/* Intersect all cylinder and plane elements. */
intersect_bound_elements(BCyl, P, D);
/* Intersect all spline segments. */
intervals = BCyl->intervals;
for (i = 0; i < BCyl->number; i++)
{
Entry = &BCyl->entry[i];
switch (intersect_thick_cylinder(BCyl, Entry, dist))
{
case 0:
break;
case 2:
if (dist[0] > EPSILON)
{
Inter.d[0] = dist[0];
Inter.n = i;
insert_hit(&Inter, intervals, &cnt);
}
else
{
if (dist[1] > EPSILON)
{
Inter.d[0] = 0.0;
Inter.n = i;
insert_hit(&Inter, intervals, &cnt);
}
}
break;
case 4:
if (dist[0] > EPSILON)
{
Inter.d[0] = dist[0];
Inter.n = i;
insert_hit(&Inter, intervals, &cnt);
}
else
{
if (dist[1] > EPSILON)
{
Inter.d[0] = 0.0;
Inter.n = i;
insert_hit(&Inter, intervals, &cnt);
}
else
{
if (dist[2] > EPSILON)
{
Inter.d[0] = dist[2];
Inter.n = i;
insert_hit(&Inter, intervals, &cnt);
}
else
{
if (dist[3] > EPSILON)
{
Inter.d[0] = 0.0;
Inter.n = i;
insert_hit(&Inter, intervals, &cnt);
}
}
}
}
break;
default:
/*
* We weren't able to find an even number of intersections. Thus
* we can't tell where the ray enters and leaves the bounding
* cylinder. To avoid problems we assume that the ray is always
* inside the cylinder in that case.
*/
Inter.d[0] = dist[0];
Inter.n = i;
insert_hit(&Inter, intervals, &cnt);
break;
}
}
return(cnt);
}
bool Superellipsoid::Intersect(const BasicRay& ray, IStack& Depth_Stack, TraceThreadData *Thread)
{
int i, cnt, Found = false;
DBL dists[PLANECOUNT+2];
DBL t, t1, t2, v0, v1, len;
Vector3d P, D, P0, P1, P2, P3;
/* Transform the ray into the superellipsoid space. */
MInvTransPoint(P, ray.Origin, Trans);
MInvTransDirection(D, ray.Direction, Trans);
len = D.length();
D /= len;
/* Intersect superellipsoid's bounding box. */
if (!intersect_box(P, D, &t1, &t2))
{
return(false);
}
/* Test if superellipsoid lies 'behind' the ray origin. */
if (t2 < DEPTH_TOLERANCE)
{
return(false);
}
cnt = 0;
if (t1 < DEPTH_TOLERANCE)
{
t1 = DEPTH_TOLERANCE;
}
dists[cnt++] = t1;
dists[cnt++] = t2;
/* Intersect ray with planes cutting superellipsoids in pieces. */
cnt = find_ray_plane_points(P, D, cnt, dists, t1, t2);
if (cnt <= 1)
{
return(false);
}
P0 = P + dists[0] * D;
v0 = evaluate_superellipsoid(P0);
if (fabs(v0) < ZERO_TOLERANCE)
{
if (insert_hit(ray, dists[0] / len, Depth_Stack, Thread))
{
if (Type & IS_CHILD_OBJECT)
{
Found = true;
}
else
{
return(true);
}
}
}
for (i = 1; i < cnt; i++)
{
P1 = P + dists[i] * D;
v1 = evaluate_superellipsoid(P1);
if (fabs(v1) < ZERO_TOLERANCE)
{
if (insert_hit(ray, dists[i] / len, Depth_Stack, Thread))
{
if (Type & IS_CHILD_OBJECT)
{
Found = true;
}
else
{
return(true);
}
}
}
else
{
if (v0 * v1 < 0.0)
{
/* Opposite signs, there must be a root between */
solve_hit1(v0, P0, v1, P1, P2);
P3 = P2 - P;
t = P3.length();
if (insert_hit(ray, t / len, Depth_Stack, Thread))
{
if (Type & IS_CHILD_OBJECT)
{
Found = true;
}
else
{
return(true);
}
}
}
else
{
/*
* Although there was no sign change, we may actually be approaching
* the surface. In this case, we are being fooled by the shape of the
* surface into thinking there isn't a root between sample points.
*/
if (check_hit2(P, D, dists[i-1], P0, v0, dists[i], &t, P2))
{
if (insert_hit(ray, t / len, Depth_Stack, Thread))
{
if (Type & IS_CHILD_OBJECT)
{
Found = true;
}
else
{
return(true);
}
}
else
{
break;
}
}
}
}
v0 = v1;
P0 = P1;
}
return(Found);
}
