edu.illinois.cs.cs125.fall2019.mp

Class LineCrossDetector

java.lang.Object

edu.illinois.cs.cs125.fall2019.mp.LineCrossDetector

public class LineCrossDetector
extends java.lang.Object

Holds a method to determine whether two lines cross.

The implementation given here works. You do not need to change the logic, but there are some style problems that you do need to correct.

This file will be revisited in Checkpoint 3.

Constructor Summary

Constructors

Constructor and Description
LineCrossDetector()

Method Summary

Modifier and Type	Method and Description
static boolean	linesCross(double firstStartLat, double firstStartLng, double firstEndLat, double firstEndLng, double secondStartLat, double secondStartLng, double secondEndLat, double secondEndLng) Determines whether two lines cross.

Methods inherited from class java.lang.Object

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

Constructor Detail

LineCrossDetector

public LineCrossDetector()

Method Detail

linesCross

public static boolean linesCross(double firstStartLat,
                                 double firstStartLng,
                                 double firstEndLat,
                                 double firstEndLng,
                                 double secondStartLat,
                                 double secondStartLng,
                                 double secondEndLat,
                                 double secondEndLng)

Determines whether two lines cross.

Crossing is not always the same as intersecting. Lines that share a tip intersect but do not cross for purposes of this function. However, a line that has an endpoint on the middle of another line must be considered to cross that line (to prevent circumventing the snake rule).

For simplicity, longitude and latitude are treated as X and Y, respectively, on a 2D coordinate plane. This ignores the roundness of the earth, but it's undetectable at reasonable scales of the game.

All parameters are assumed to be valid: both lines have positive length.

Parameters:

firstStartLat - the latitude of the start of one line

firstStartLng - the longitude of the start of that line

firstEndLat - the latitude of the end of that line

firstEndLng - the longitude of the end of that line

secondStartLat - the latitude of the start of another line

secondStartLng - the longitude of the start of that other line

secondEndLat - the latitude of the end of that other line

secondEndLng - the longitude of the end of that other line

Returns:

whether the two lines cross