net.stemkoski.bagel

Class Vector2

java.lang.Object

net.stemkoski.bagel.Vector2

All Implemented Interfaces:

java.lang.Comparable<Vector2>

public class Vector2
extends java.lang.Object
implements java.lang.Comparable<Vector2>

A two-dimensional vector (x,y), particularly useful for representing velocity and acceleration (see Physics), and minimum translation vectors for collision resolution (see Rectangle, TileMap).

Field Summary

Fields

Modifier and Type	Field and Description
double	x x-coordinate of the vector
double	y y-coordinate of the vector

Constructor Summary

Constructors

Constructor and Description
Vector2() Initializes vector coordinates to (0,0).
Vector2(double x, double y) Initializes vector coordinates to (x,y).

Method Summary

Modifier and Type	Method and Description
void	addValues(double dx, double dy) Add values to the coordinates of this vector.
void	addVector(Vector2 other) Add the values of the coordinates of other vector to the coordinates of this vector.
int	compareTo(Vector2 other) Required method from Comparable interface; used to sort collections of Vector2 objects by length, particularly for use in determining the minimum (shortest) translation vector for use in resolving collisions with solid objects.
double	getAngle() Calculate the angle (in degrees) between this vector and the x-axis (the vector (1,0)).
double	getLength() Calculate the length of this vector
void	multiply(double scalar) Multiple the coordinates of this vector by a given value.
void	setAngle(double angleDegrees) Changes the angle of this vector to angleDegrees while preserving the length of this vector.
void	setLength(double length) Changes the length of this vector to length while preserving the angle of this vector.
void	setValues(double x, double y) Set the values of the x- and y- coordinates.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

x

public double x

x-coordinate of the vector

y

public double y

y-coordinate of the vector

Constructor Detail

Vector2

public Vector2()

Initializes vector coordinates to (0,0).

Vector2

public Vector2(double x,
               double y)

Initializes vector coordinates to (x,y).

Parameters:

x - x-coordinate

y - y-coordinate

Method Detail

setValues

public void setValues(double x,
                      double y)

Set the values of the x- and y- coordinates.

Parameters:

x - x-coordinate

y - y-coordinate

addVector

public void addVector(Vector2 other)

Add the values of the coordinates of other vector to the coordinates of this vector.

Parameters:

other - vector to be added to this vector

addValues

public void addValues(double dx,
                      double dy)

Add values to the coordinates of this vector.

Parameters:

dx - value to add to the x-coordinate

dy - value to add to the y-coordinate

multiply

public void multiply(double scalar)

Multiple the coordinates of this vector by a given value.

Parameters:

scalar - the value to multiply the coordinates of this vector by

getLength

public double getLength()

Calculate the length of this vector

Returns:

the length of this vector

getAngle

public double getAngle()

Calculate the angle (in degrees) between this vector and the x-axis (the vector (1,0)). If this vector is the zero vector, returns 0. Return values are in the range from -180 to +180.

Returns:

the angle between this vector and the x-axis

setLength

public void setLength(double length)

Changes the length of this vector to length while preserving the angle of this vector.

Parameters:

length - the new length of this vector

setAngle

public void setAngle(double angleDegrees)

Changes the angle of this vector to angleDegrees while preserving the length of this vector.

Parameters:

angleDegrees - the new angle (in degrees) between this vector and the x-axis

compareTo

public int compareTo(Vector2 other)

Required method from Comparable interface; used to sort collections of Vector2 objects by length, particularly for use in determining the minimum (shortest) translation vector for use in resolving collisions with solid objects.

Specified by:

compareTo in interface java.lang.Comparable<Vector2>

Parameters:

other - the vector being compared against this vector

Returns:

+1 if this vector is larger than other vector, -1 if other vector is larger than this vector, 0 if vectors have same length

See Also:

Comparable.compareTo(java.lang.Object)

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object