public Intersections FilterIntersections(Intersections xs)
{
var inl = false;
var inr = false;
var result = new Intersections();
foreach (var i in xs)
{
var lhit = this.Left.Contains(i.Shape);
if (this.Operation.IntersectionAllowed(lhit, inl, inr))
{
result.Add(i);
}
if (lhit)
{
inl = !inl;
}
else
{
inr = !inr;
}
}
return(result);
}
protected override Intersections IntersectsInt(Ray r)
{
var a = (r.Direction.x * r.Direction.x) -
(r.Direction.y * r.Direction.y) +
(r.Direction.z * r.Direction.z);
var b = 2 * r.Origin.x * r.Direction.x -
2 * r.Origin.y * r.Direction.y +
2 * r.Origin.z * r.Direction.z;
var c = (r.Origin.x * r.Origin.x) -
(r.Origin.y * r.Origin.y) +
(r.Origin.z * r.Origin.z);
var disc = (b * b) - 4 * a * c;
if (disc < 0)
{
return(Intersections.EMPTY);
}
double[] ts;
if (a == 0)
{
ts = new double[] { -c / (2 * b) };
}
else
{
var t0 = (-b - Math.Sqrt(disc)) / (2 * a);
var t1 = (-b + Math.Sqrt(disc)) / (2 * a);
if (t0 > t1)
{
Swap(ref t0, ref t1);
}
ts = new double[] { t0, t1 };
}
var xs = new Intersections();
foreach (var t in ts)
{
var y = r.Origin.y + t * r.Direction.y;
if (Minimum < y && y < Maximum)
{
xs.Add(new Intersection(t, this));
}
}
IntersectCaps(r, xs);
return(xs);
}
private void IntersectCaps(Ray r, Intersections xs)
{
if (!this.Closed || Math.Abs(r.Direction.y) < EPSILON)
{
return;
}
foreach (var v in new double[] { Minimum, Maximum })
{
var t = (v - r.Origin.y) / r.Direction.y;
if (CheckCap(r, t, Math.Abs(v)))
{
xs.Add(new Intersection(t, this));
}
}
}