// returns first intersection point with box boundary or null if there are none
public static Vector2?MeetingPoint(this Ray2 ray, Box2 box)
{
var meetingDistance = double.PositiveInfinity;
for (Vector2.Axis axis = 0; axis < Vector2.Axis.Count; axis++)
{
var otherAxis = 1 - axis;
for (Interval.EndType end = 0; end < Interval.EndType.Count; end++)
{
var intersectionDistance = (box.Corner(end)[axis] - ray.Origin[axis]) / ray.Direction[axis];
if (intersectionDistance > 0)
{
var intersectionCoord = ray.Origin[otherAxis] + ray.Direction[otherAxis] * intersectionDistance;
if (box.Range(otherAxis).Contains(intersectionCoord))
{
meetingDistance = Math.Min(meetingDistance, intersectionDistance);
}
}
}
}
if (double.IsPositiveInfinity(meetingDistance))
{
return(null);
}
return(ray.PointAt(meetingDistance));
}
public static Vector2 Corner(this Box2 @this, Interval.EndType end)
{
switch (end)
{
case Interval.EndType.Min:
return(@this.MinCorner);
case Interval.EndType.Max:
return(@this.MaxCorner);
default:
throw new ArgumentOutOfRangeException("end", end, "Illegal EndType " + end.ToString());
}
}
