public double GetSquared()
{
if (DistanceSquared >= 0)
{
return(DistanceSquared);
}
// Work in the box's coordinate system.
Vector2D diff = point - box.Center;
// Compute squared distance and closest point on box.
double sqrDistance = (double)0;
double delta;
Vector2D closest = Vector2D.Zero;
int i;
for (i = 0; i < 2; ++i)
{
closest[i] = diff.Dot(box.Axis(i));
if (closest[i] < -box.Extent[i])
{
delta = closest[i] + box.Extent[i];
sqrDistance += delta * delta;
closest[i] = -box.Extent[i];
}
else if (closest[i] > box.Extent[i])
{
delta = closest[i] - box.Extent[i];
sqrDistance += delta * delta;
closest[i] = box.Extent[i];
}
}
BoxClosest = box.Center;
for (i = 0; i < 2; ++i)
{
BoxClosest += closest[i] * box.Axis(i);
}
DistanceSquared = sqrDistance;
return(sqrDistance);
}