samer@0: /*
samer@0:  *	Copyright (c) 2000, Samer Abdallah, King's College London.
samer@0:  *	All rights reserved.
samer@0:  *
samer@0:  *	This software is provided AS iS and WITHOUT ANY WARRANTY; 
samer@0:  *	without even the implied warranty of MERCHANTABILITY or 
samer@0:  *	FITNESS FOR A PARTICULAR PURPOSE.
samer@0:  */
samer@0: 
samer@0: package samer.tools;
samer@0: 
samer@0: public class vec2 implements java.io.Serializable {
samer@0:    public double x, y;
samer@0: 
samer@0:    public double norm()        { return x*x+y*y; }
samer@0:    public vec2 neg()           { return new vec2(-x,-y); }
samer@0:    public void add( vec2 a)    { x+=a.x; y+=a.y; }
samer@0:    public void sub( vec2 a)    { x-=a.x; y-=a.y; }
samer@0:    public void mul( double k)  { x*=k; y*=k; }
samer@0:    public void div( double k)  { x/=k; y/=k; }
samer@0:    public void assign( vec2 a) { x=a.x; y=a.y; }
samer@0:    public void assign( double i, double j) { x=i; y=j; }
samer@0:    public void normalise()     { div( Math.sqrt(norm())); }
samer@0: 
samer@0:    public static vec2 add( vec2 a, vec2 b)   { return new vec2(a.x+b.x,a.y+b.y); }
samer@0:    public static vec2 sub( vec2 a, vec2 b)   { return new vec2(a.x-b.x,a.y-b.y); }
samer@0:    public static vec2 div( vec2 a, double k) { return new vec2(a.x/k,a.y/k); }
samer@0:    public static vec2 mul( vec2 a, double k) { return new vec2(a.x*k,a.y*k); }
samer@0:    public static vec2 mul( double k, vec2 a) { return new vec2(a.x*k,a.y*k); }
samer@0:    public static double dot( vec2 a, vec2 b) { return a.x*b.x + a.y*b.y; }
samer@0: 
samer@0:    public vec2()        {}
samer@0:    public vec2( vec2 a) { x=a.x; y=a.y; }
samer@0:    public vec2( double i, double j) { x=i; y=j; }
samer@0: }