Vector2d.java

public class Vector2d {
	public double x, y;
	
	Vector2d(double x, double y) {
		this.x = x;
		this.y = y;
	}
	
	Vector2d() {
		this.x = 0.0;
		this.y = 0.0;
	}
	
	public void set(double x, double y) {
		this.x = x;
		this.y = y;
	}
	
	public void set(Vector2d o) {
		this.x = o.x;
		this.y = o.y;
	}
	
	public double magSqr() {
		return x*x + y*y;
	}
	
	public double mag() {
		return Math.sqrt(x*x + y*y);
	}
	
	public void normalize() {
		double len = mag();
		x /= len;
		y /= len;
	}
	
	public void mult(double m) {
		x *= m;
		y *= m;
	}
	
	public void setMag(double m) {
		normalize();
		mult(m);
	}
	
	public void limit(double maxMag) {
		double m = magSqr();
		if (m > maxMag*maxMag) {
			setMag(maxMag);
		}
	}
	
	public double angTo(Vector2d o) {
		return Math.atan2(y - o.y , x - o.x);
	}
	
	public void add(Vector2d o) {
		x += o.x;
		y += o.y;
	}
	
	public void add(double x, double y) {
		this.x += x;
		this.y += y;
	}
	
	public void sub(Vector2d o) {
		x -= o.x;
		y -= o.y;
	}
	
	public void sub(double x, double y) {
		this.x -= x;
		this.y -= y;
	}
	
	@Override
	public String toString() {
		return "" + x + "," + y;
	}
}