/// <summary>
/// Computes an intersection of the ray and the segment
/// </summary>
public static bool RaySegment(Vector2 rayOrigin, Vector2 rayDirection, Vector2 segmentA, Vector2 segmentB,
out IntersectionRaySegment2 intersection)
{
Vector2 segmentAToOrigin = rayOrigin - segmentA;
Vector2 segmentDirection = segmentB - segmentA;
float denominator = VectorE.PerpDot(rayDirection, segmentDirection);
float perpDotA = VectorE.PerpDot(rayDirection, segmentAToOrigin);
// Normalized direction gives more stable results
float perpDotB = VectorE.PerpDot(segmentDirection.normalized, segmentAToOrigin);
if (Mathf.Abs(denominator) < Geometry.Epsilon)
{
// Parallel
if (Mathf.Abs(perpDotA) > Geometry.Epsilon || Mathf.Abs(perpDotB) > Geometry.Epsilon)
{
// Not collinear
intersection = IntersectionRaySegment2.None();
return(false);
}
// Collinear
bool segmentIsAPoint = segmentDirection.sqrMagnitude < Geometry.Epsilon;
float segmentAProjection = Vector2.Dot(rayDirection, segmentA - rayOrigin);
if (segmentIsAPoint)
{
if (segmentAProjection > -Geometry.Epsilon)
{
intersection = IntersectionRaySegment2.Point(segmentA);
return(true);
}
intersection = IntersectionRaySegment2.None();
return(false);
}
float segmentBProjection = Vector2.Dot(rayDirection, segmentB - rayOrigin);
if (segmentAProjection > -Geometry.Epsilon)
{
if (segmentBProjection > -Geometry.Epsilon)
{
if (segmentBProjection > segmentAProjection)
{
intersection = IntersectionRaySegment2.Segment(segmentA, segmentB);
}
else
{
intersection = IntersectionRaySegment2.Segment(segmentB, segmentA);
}
}
else
{
if (segmentAProjection > Geometry.Epsilon)
{
intersection = IntersectionRaySegment2.Segment(rayOrigin, segmentA);
}
else
{
intersection = IntersectionRaySegment2.Point(rayOrigin);
}
}
return(true);
}
if (segmentBProjection > -Geometry.Epsilon)
{
if (segmentBProjection > Geometry.Epsilon)
{
intersection = IntersectionRaySegment2.Segment(rayOrigin, segmentB);
}
else
{
intersection = IntersectionRaySegment2.Point(rayOrigin);
}
return(true);
}
intersection = IntersectionRaySegment2.None();
return(false);
}
// Not parallel
float rayDistance = perpDotB / denominator;
float segmentDistance = perpDotA / denominator;
if (rayDistance > -Geometry.Epsilon &&
segmentDistance > -Geometry.Epsilon && segmentDistance < 1 + Geometry.Epsilon)
{
intersection = IntersectionRaySegment2.Point(segmentA + segmentDirection * segmentDistance);
return(true);
}
intersection = IntersectionRaySegment2.None();
return(false);
}
/// <summary>
/// Computes an intersection of the ray and the segment
/// </summary>
public static bool RaySegment(Vector2 rayOrigin, Vector2 rayDirection, Vector2 segmentA, Vector2 segmentB,
out IntersectionRaySegment2 intersection)
{
float rayDistance;
float segmentDistance;
Vector2 segmentDirection = segmentB - segmentA;
var intersectionType = LineLine(rayOrigin, rayDirection, segmentA, segmentDirection, out rayDistance, out segmentDistance);
if (intersectionType == IntersectionType.Line)
{
bool segmentIsAPoint = segmentDirection.sqrMagnitude < Geometry.Epsilon;
float projectionFromOriginToA = Vector2.Dot(rayDirection, segmentA - rayOrigin);
if (segmentIsAPoint)
{
if (projectionFromOriginToA > -Geometry.Epsilon)
{
intersection = IntersectionRaySegment2.Point(segmentA);
return(true);
}
intersection = IntersectionRaySegment2.None();
return(false);
}
float projectionFromOriginToB = Vector2.Dot(rayDirection, segmentB - rayOrigin);
if (projectionFromOriginToA > -Geometry.Epsilon)
{
if (projectionFromOriginToB > -Geometry.Epsilon)
{
if (projectionFromOriginToB > projectionFromOriginToA)
{
intersection = IntersectionRaySegment2.Segment(segmentA, segmentB);
}
else
{
intersection = IntersectionRaySegment2.Segment(segmentB, segmentA);
}
}
else
{
if (projectionFromOriginToA > Geometry.Epsilon)
{
intersection = IntersectionRaySegment2.Segment(rayOrigin, segmentA);
}
else
{
intersection = IntersectionRaySegment2.Point(rayOrigin);
}
}
return(true);
}
if (projectionFromOriginToB > -Geometry.Epsilon)
{
if (projectionFromOriginToB > Geometry.Epsilon)
{
intersection = IntersectionRaySegment2.Segment(rayOrigin, segmentB);
}
else
{
intersection = IntersectionRaySegment2.Point(rayOrigin);
}
return(true);
}
intersection = IntersectionRaySegment2.None();
return(false);
}
if (intersectionType == IntersectionType.Point &&
rayDistance > -Geometry.Epsilon &&
segmentDistance > -Geometry.Epsilon && segmentDistance < 1 + Geometry.Epsilon)
{
intersection = IntersectionRaySegment2.Point(rayOrigin + rayDirection * rayDistance);
return(true);
}
intersection = IntersectionRaySegment2.None();
return(false);
}