/// <summary>
/// Computes an intersection of the rays
/// </summary>
public static bool IntersectRayRay(Ray2D rayA, Ray2D rayB, out IntersectionRayRay2 intersection)
{
return(IntersectRayRay(rayA.origin, rayA.direction, rayB.origin, rayB.direction, out intersection));
}
/// <summary>
/// Computes an intersection of the rays
/// </summary>
public static bool IntersectRayRay(Vector2 originA, Vector2 directionA, Vector2 originB, Vector2 directionB,
out IntersectionRayRay2 intersection)
{
intersection = new IntersectionRayRay2();
Vector2 originBToA = originA - originB;
float denominator = VectorE.PerpDot(directionA, directionB);
float perpDotA = VectorE.PerpDot(directionA, originBToA);
float perpDotB = VectorE.PerpDot(directionB, originBToA);
if (Mathf.Abs(denominator) < Epsilon)
{
// Parallel
if (Mathf.Abs(perpDotA) > Epsilon || Mathf.Abs(perpDotB) > Epsilon)
{
// Not collinear
intersection.type = IntersectionType.None;
return(false);
}
// Collinear
bool codirected = Vector2.Dot(directionA, directionB) > 0;
float dotA = Vector2.Dot(directionA, originBToA);
if (codirected)
{
intersection.type = IntersectionType.Ray;
intersection.pointA = dotA > 0 ? originA : originB;
intersection.pointB = directionA;
return(true);
}
else
{
if (dotA > 0)
{
intersection.type = IntersectionType.None;
return(false);
}
else
{
intersection.type = IntersectionType.Segment;
intersection.pointA = originA;
intersection.pointB = originB;
return(true);
}
}
}
// The rays are skew and may intersect in a point
float distanceA = perpDotB / denominator;
if (distanceA < -Epsilon)
{
intersection.type = IntersectionType.None;
return(false);
}
float distanceB = perpDotA / denominator;
if (distanceB < -Epsilon)
{
intersection.type = IntersectionType.None;
return(false);
}
intersection.type = IntersectionType.Point;
intersection.pointA = originA + directionA * distanceA;
return(true);
}
/// <summary>
/// Computes an intersection of the rays
/// </summary>
public static bool RayRay(Vector2 originA, Vector2 directionA, Vector2 originB, Vector2 directionB,
out IntersectionRayRay2 intersection)
{
Vector2 originBToA = originA - originB;
float denominator = VectorE.PerpDot(directionA, directionB);
float perpDotA = VectorE.PerpDot(directionA, originBToA);
float perpDotB = VectorE.PerpDot(directionB, originBToA);
if (Mathf.Abs(denominator) < Geometry.Epsilon)
{
// Parallel
if (Mathf.Abs(perpDotA) > Geometry.Epsilon || Mathf.Abs(perpDotB) > Geometry.Epsilon)
{
// Not collinear
intersection = IntersectionRayRay2.None();
return(false);
}
// Collinear
bool codirected = Vector2.Dot(directionA, directionB) > 0;
float originBProjection = -Vector2.Dot(directionA, originBToA);
if (codirected)
{
intersection = IntersectionRayRay2.Ray(originBProjection > 0 ? originB : originA, directionA);
return(true);
}
else
{
if (originBProjection < -Geometry.Epsilon)
{
intersection = IntersectionRayRay2.None();
return(false);
}
if (originBProjection < Geometry.Epsilon)
{
intersection = IntersectionRayRay2.Point(originA);
return(true);
}
intersection = IntersectionRayRay2.Segment(originA, originB);
return(true);
}
}
// Not parallel
float distanceA = perpDotB / denominator;
if (distanceA < -Geometry.Epsilon)
{
intersection = IntersectionRayRay2.None();
return(false);
}
float distanceB = perpDotA / denominator;
if (distanceB < -Geometry.Epsilon)
{
intersection = IntersectionRayRay2.None();
return(false);
}
intersection = IntersectionRayRay2.Point(originA + directionA * distanceA);
return(true);
}