Package me.wobblyyyy.pathfinder.geometry

Class Line

java.lang.Object
me.wobblyyyy.pathfinder.geometry.Line
public class Line
extends java.lang.Object
A combination of two points, forming a line. Incredible, truly!

You should NOT use the Line class as a method of measuring the distance between two points. Rather, the Distance class has a lovely little static method named "getDistance" that'll do exactly that for you.

Lines are a core component of many shapes, namely rectangles and squares. Aside from using those shapes, it's fairly unlikely you're going to need to use this class. But it's here anyways!

Since:
0.1.0
Author:
Colin Robertson

  • Field Summary

    Fields
    Modifier and Type Field Description
    private Point a
    One of the two points of a line.
    private Point aPoint
    The midpoint between the midpoint and A.
    private Point b
    One of the two points of a line.
    private Point bPoint
    The midpoint between the midpoint and B.
    private Point midpoint
    The midpoint of the line.

  • Constructor Summary

    Constructors
    Constructor Description
    Line​(Point a, double angle, double length)
    Create a new line from a center point, extending outwards at a given angle for a given length.
    Line​(Point a, Point b)
    Create a new line.

  • Method Summary

    Modifier and Type Method Description
    static boolean doesIntersect​(Line a, Line b)
    Check whether or not two lines collide at any point.
    Point getA()
    Get the A point.
    Point getAPoint()
    Get the point between A and the midpoint.
    Point getB()
    Get the B point.
    Point getBPoint()
    Get the point between B and the midpoint.
    double getLength()
    Get the length of the line, in units.
    Point getMidpoint()
    Get the midpoint.
    boolean isPointOnLine​(Point point)
    Check whether or not a given ordered pair lies on the instanced line.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Field Details

    • a

      private final Point a
      One of the two points of a line.

    • b

      private final Point b
      One of the two points of a line.

    • midpoint

      private final Point midpoint
      The midpoint of the line.

    • aPoint

      private final Point aPoint
      The midpoint between the midpoint and A.

    • bPoint

      private final Point bPoint
      The midpoint between the midpoint and B.

  • Constructor Details

    • Line

      public Line​(Point a, Point b)
      Create a new line.

      Lines have five major points:

      • A (you provide this one)
      • B (you provide this one)
      • Midpoint (in between A and B)
      • A-Point (in between A and the midpoint)
      • B-Point (in between B and the midpoint)

      Parameters:
      a - one of the line's two points.
      b - one of the line's two points.

    • Line

      public Line​(Point a, double angle, double length)
      Create a new line from a center point, extending outwards at a given angle for a given length.

      Lines have five major points:

      • A (you provide this one)
      • B (you provide this one)
      • Midpoint (in between A and B)
      • A-Point (in between A and the midpoint)
      • B-Point (in between B and the midpoint)

      Parameters:
      a - the line's center-point.
      angle - the angle at which the line should be drawn.
      length - the length of the line to draw.

  • Method Details

    • getA

      public Point getA()
      Get the A point.
      Returns:
      the A point.

    • getB

      public Point getB()
      Get the B point.
      Returns:
      the B point.

    • getMidpoint

      public Point getMidpoint()
      Get the midpoint.
      Returns:
      the midpoint.

    • getAPoint

      public Point getAPoint()
      Get the point between A and the midpoint.
      Returns:
      the point between A and the midpoint.

    • getBPoint

      public Point getBPoint()
      Get the point between B and the midpoint.
      Returns:
      the point between B and the midpoint.

    • getLength

      public double getLength()
      Get the length of the line, in units.

      Mapping has nothing to do with units - whatever unit you put in, you'll get out.

      Returns:
      the length of the line in (?) units.

    • doesIntersect

      public static boolean doesIntersect​(Line a, Line b)
      Check whether or not two lines collide at any point.

      Prior to reaching this stage of virtual collision detection, check to make sure none of the following conditions are true...

      • Lines are parallel.
      • Line intersection is theoretically impossible due to distance.
      • Line intersection is, for another reason, theoretically impossible.

      A, B, and C are numbers which define each of the lines. Given two sets of points, (x1, y1) and (x2, y2) we can determine the point of intersection between the two lines. After finding this point of intersection, however, we still have to make sure that that point of intersection is actually on both of the lines, ensuring a virtual collision is indeed happening. 

       A = y2-y1;
 B = x1-x2;
 C = Ax1+By1;

      Parameters:
      a - the first line
      b - the second line
      Returns:
      whether or not the lines intersect

    • isPointOnLine

      public boolean isPointOnLine​(Point point)
      Check whether or not a given ordered pair lies on the instanced line.

      "If your line segment goes from (x1, y1) to (x2, y2), then to check if (x, y) is on that segment, you just need to check that min(x1, x2) <= x <= max(x1, x2), and do the same thing for Y."

      In order to check whether or not two lines collide at any point, we have to first ensure that there is indeed a point of collision. This may, in the near future, need to be adjusted using comparators to allow for certain degrees of tolerance to ensure that points are very nearly on the line rather than on the line - simply checking if a point is on a given line could sometimes be inaccurate.

      Parameters:
      point - a given pair
      Returns:
      whether or not that point is on this line