intersections method

List<Vector2> intersections(LineSegment otherSegment)

Returns an empty list if there are no intersections between the segments If the segments are concurrent, the intersecting point is returned as a list with a single point

Implementation

List<Vector2> intersections(LineSegment otherSegment) {
  final result = toLine().intersections(otherSegment.toLine());
  if (result.isNotEmpty) {
    // The lines are not parallel
    final intersection = result.first;
    if (containsPoint(intersection) &&
        otherSegment.containsPoint(intersection)) {
      // The intersection point is on both line segments
      return result;
    }
  } else {
    // In here we know that the lines are parallel
    final overlaps = ({
      from: otherSegment.containsPoint(from),
      to: otherSegment.containsPoint(to),
      otherSegment.from: containsPoint(otherSegment.from),
      otherSegment.to: containsPoint(otherSegment.to),
    }..removeWhere((_key, onSegment) => !onSegment))
        .keys
        .toSet();
    if (overlaps.isNotEmpty) {
      return [
        overlaps.fold<Vector2>(
              Vector2.zero(),
              (sum, point) => sum + point,
            ) /
            overlaps.length.toDouble(),
      ];
    }
  }
  return [];
}