/// <summary>
/// returns null if ray does not hit the line. When hit, returns the distance from the hit point
/// </summary>
/// <param name="line">Line barrier</param>
/// <returns>distance of ray origins from the hit point along the ray direction</returns>
public double?DistanceToForIsovist(UVLine line, double tolerance)
{
//checking if the lines intersect at all
double vs = this.Direction.CrossProductValue(this.Origin - line.Start);
double ve = this.Direction.CrossProductValue(this.Origin - line.End);
if (vs * ve > -tolerance)
{
return(null);
}
//finding the intersection
if (vs == 0)
{
return(this.Origin.DistanceTo(line.Start));
}
else if (ve == 0)
{
return(this.Origin.DistanceTo(line.End));
}
else
{
double _length = line.GetLength();
vs = Math.Abs(vs);
ve = Math.Abs(ve);
double lengthFromStart = _length * vs / (vs + ve);
UV hitPoint = line.FindPoint(lengthFromStart);
return(this.Origin.DistanceTo(hitPoint));
}
}
/// <summary>
/// returns null if ray does not hit the line. When hit, returns the distance from the hit point
/// </summary>
/// <param name="hitPoint">Hit point on the barrier</param>
/// <param name="line">Line barrier</param>
/// <returns>distance of ray origins from the hit point along the ray direction</returns>
public double?DistanceTo(UVLine line, ref UV hitPoint, double tolerance = 0.0001)
{
hitPoint = null;
double?result = null;
double vs = this.Direction.CrossProductValue(this.Origin - line.Start);
double ve = this.Direction.CrossProductValue(this.Origin - line.End);
if (vs * ve > tolerance)
{
return(null);
}
if (vs == 0)
{
result = this.Origin.DistanceTo(line.Start);
hitPoint = line.Start;
}
else if (ve == 0)
{
result = this.Origin.DistanceTo(line.End);
hitPoint = line.End;
}
else
{
double _length = line.GetLength();
vs = Math.Abs(vs);
ve = Math.Abs(ve);
double lengthFromStart = _length * vs / (vs + ve);
hitPoint = line.FindPoint(lengthFromStart);
result = this.Origin.DistanceTo(hitPoint);
}
if (result != null)
{
var hitDirection = hitPoint - this.Origin;
if (hitDirection.DotProduct(this.Direction) < 0)
{
result = null;
hitPoint = null;
}
}
return(result);
}
