/// <summary>
/// Computes an intersection of the line and the segment
/// </summary>
public static bool LineSegment(Vector2 lineOrigin, Vector2 lineDirection, Vector2 segmentA, Vector2 segmentB,
out IntersectionLineSegment2 intersection)
{
Vector2 segmentAToOrigin = lineOrigin - segmentA;
Vector2 segmentDirection = segmentB - segmentA;
float denominator = VectorE.PerpDot(lineDirection, segmentDirection);
float perpDotA = VectorE.PerpDot(lineDirection, segmentAToOrigin);
if (Mathf.Abs(denominator) < Geometry.Epsilon)
{
// Parallel
// Normalized direction gives more stable results
float perpDotB = VectorE.PerpDot(segmentDirection.normalized, segmentAToOrigin);
if (Mathf.Abs(perpDotA) > Geometry.Epsilon || Mathf.Abs(perpDotB) > Geometry.Epsilon)
{
// Not collinear
intersection = IntersectionLineSegment2.None();
return(false);
}
// Collinear
bool segmentIsAPoint = segmentDirection.sqrMagnitude < Geometry.Epsilon;
if (segmentIsAPoint)
{
intersection = IntersectionLineSegment2.Point(segmentA);
return(true);
}
bool codirected = Vector2.Dot(lineDirection, segmentDirection) > 0;
if (codirected)
{
intersection = IntersectionLineSegment2.Segment(segmentA, segmentB);
}
else
{
intersection = IntersectionLineSegment2.Segment(segmentB, segmentA);
}
return(true);
}
// Not parallel
float segmentDistance = perpDotA / denominator;
if (segmentDistance > -Geometry.Epsilon && segmentDistance < 1 + Geometry.Epsilon)
{
intersection = IntersectionLineSegment2.Point(segmentA + segmentDirection * segmentDistance);
return(true);
}
intersection = IntersectionLineSegment2.None();
return(false);
}
/// <summary>
/// Computes an intersection of the line and the segment
/// </summary>
public static bool LineSegment(Vector2 lineOrigin, Vector2 lineDirection, Vector2 segmentA, Vector2 segmentB,
out IntersectionLineSegment2 intersection)
{
float lineDistance;
float segmentDistance;
Vector2 segmentDirection = segmentB - segmentA;
var intersectionType = LineLine(lineOrigin, lineDirection, segmentA, segmentDirection, out lineDistance, out segmentDistance);
if (intersectionType == IntersectionType.Line)
{
bool segmentIsAPoint = segmentDirection.sqrMagnitude < Geometry.Epsilon;
if (segmentIsAPoint)
{
intersection = IntersectionLineSegment2.Point(segmentA);
return(true);
}
bool codirected = Vector2.Dot(lineDirection, segmentB - segmentA) > 0;
if (codirected)
{
intersection = IntersectionLineSegment2.Segment(segmentA, segmentB);
}
else
{
intersection = IntersectionLineSegment2.Segment(segmentB, segmentA);
}
return(true);
}
if (intersectionType == IntersectionType.Point &&
segmentDistance > -Geometry.Epsilon && segmentDistance < 1 + Geometry.Epsilon)
{
intersection = IntersectionLineSegment2.Point(lineOrigin + lineDirection * lineDistance);
return(true);
}
intersection = IntersectionLineSegment2.None();
return(false);
}