public Vector3d[] GetIntersections(Triangle triangle)
{
// 3本の線分と平面との交差判定に還元する
var intersections = new HashSet <string>();
var lineSegments =
new [] {
new LineSegment(triangle.Point0, triangle.Point1),
new LineSegment(triangle.Point1, triangle.Point2),
new LineSegment(triangle.Point2, triangle.Point0)
};
var result = new List <Vector3d>();
for (var i = 0; i < lineSegments.Length; ++i)
{
var tempIntersection = GetIntersection(lineSegments[i]);
if (tempIntersection.HasValue)
{
var key = Approximation.ToApproximatedString(tempIntersection.Value);
if (intersections.Add(key))
{
result.Add(tempIntersection.Value);
}
}
}
return(result.ToArray());
}
/// <summary>
/// 線分と多角形(の境界線分)の交点を取得します
/// [契約] 線分と多角形が1つの平面上に乗っている
/// [注意] 互いに平行な線分同士 (両者が重なる場合含む) では交点は考えません
/// </summary>
/// <param name="lineSegment"></param>
/// <returns></returns>
public List <Vector3d> GetPlanarIntersections(LineSegment lineSegment)
{
if (!IsValid)
{
return(null);
}
var intersections = new List <Vector3d>();
var dicPoints = new HashSet <string>();
for (var i = 0; i < Points.Length; ++i)
{
var polygonSegment =
new LineSegment(Points[i],
Points[(i + 1) % Points.Length]);
var intersection =
polygonSegment.GetIntersection(lineSegment);
if (!intersection.HasValue)
{
continue;
}
var codedIntersection = Approximation.ToApproximatedString(intersection.Value);
if (dicPoints.Add(codedIntersection))
{
intersections.Add(intersection.Value);
}
}
return(intersections);
}