source: branches/2817-BinPackingSpeedup/HeuristicLab.Problems.BinPacking/3.3/3D/Geometry/Edge3D.cs

#region License Information
/* HeuristicLab
 * Copyright (C) 2002-2018 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
 *
 * This file is part of HeuristicLab.
 *
 * HeuristicLab is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * HeuristicLab is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
 */
#endregion

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace HeuristicLab.Problems.BinPacking3D.Geometry {
  public class Edge3D {
    public Edge3D() { }

    public Edge3D(PackingPosition start, PackingPosition end) {
      Start = new Vector3D(start);
      End = new Vector3D(end);
    }

    public Edge3D(Vector3D start, Vector3D end) {
      Start = start;
      End = end;
    }

    public Vector3D Start { get; set; }
    public Vector3D End { get; set; }


    

    /// <summary>
    /// Returns true if a given point lies on the edge.
    /// </summary>
    /// <param name="point"></param>
    /// <returns>Returns true if a given point lies on the edge.</returns>
    public bool LiesOn(Vector3D point) {
      if (point == null) {
        return false;
      }
      var x = (Start.X <= point.X && point.X <= End.X) || (Start.X >= point.X && point.X >= End.X);
      var y = (Start.Y <= point.Y && point.Y <= End.Y) || (Start.Y >= point.Y && point.Y >= End.Y);
      var z = (Start.Z <= point.Z && point.Z <= End.Z) || (Start.Z >= point.Z && point.Z >= End.Z);
      return x && y && z;
    }


    /// <summary>
    /// Returns a point where the two edges intersects.
    /// It returns null if they don't intersect.
    /// </summary>
    /// <param name="edge"></param>
    /// <returns>Returns a point where the two edges intersects. Null = no intersection.</returns>
    public Vector3D Intersects(Edge3D edge) {
      return Intersects(this, edge);
    }

    /// <summary>
    /// Returns a point where two edges are intersecting.
    /// It returns null if they don't intersect.
    /// </summary>
    /// <param name="e1"></param>
    /// <param name="e2"></param>
    /// <returns>Returns a point where the two edges intersects. Null = no intersection.</returns>
    public static Vector3D Intersects(Edge3D e1, Edge3D e2) {
      Line3D l1 = new Line3D(e1.Start, new Vector3D() {
        X = e1.Start.X - e1.End.X,
        Y = e1.Start.Y - e1.End.Y,
        Z = e1.Start.Z - e1.End.Z
      });
      Line3D l2 = new Line3D(e2.Start, new Vector3D() {
        X = e2.Start.X - e2.End.X,
        Y = e2.Start.Y - e2.End.Y,
        Z = e2.Start.Z - e2.End.Z
      });
      Vector3D point = l1.Intersect(l2);
      if (point != null && e1.LiesOn(point) && e2.LiesOn(point)) {
        return point;
      }
      return null;
    }
  }
}