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package net.phatcode.rel;
public class Vector2D
{
public static final float EPSILON = 0.0000000001f;
public float x;
public float y;
public Vector2D()
{
x = 0;
y = 0;
}
public Vector2D( float a, float b )
{
x = a;
y = b;
}
public Vector2D( Vector2D v )
{
x = v.x;
y = v.y;
}
public float magnitude()
{
return (float)Math.sqrt( (x * x) + (y * y) );
}
public float magnitudeSquared()
{
return ( (x * x) + (y * y) );
}
public float dot( Vector2D v )
{
return ( (x * v.x) + (y * v.y) );
}
public Vector2D normal( boolean side )
{
return ( side == false ) ? new Vector2D( -y, x ) : new Vector2D( y, -x );
}
public float normalize()
{
float length = magnitude();
float invMag = 1.0f/length;
if( length <= EPSILON ) return 0.0f;
x *= invMag;
y *= invMag;
return length;
}
public void scale( float s )
{
x *= s;
y *= s;
}
public float angleBetween( Vector2D v )
{
return (float)(Math.atan2(v.y - y, v.x - x));
}
public Vector2D reflect( Vector2D n )
{
float dot = (x * n.x) + (y * n.y);
Vector2D n2 = new Vector2D( n.x * -2.0f, n.y * -2.0f );
n2.scale(dot);
n2.x += x;
n2.y += y;
return n2;
}
public void displayComponents()
{
System.out.println( "v.x = " + x + " :: v.y = " + y );
}
public String toString()
{
return ( "v.x = " + x + " :: v.y = " + y );
}
public static float magnitude( Vector2D v )
{
return v.magnitude();
}
public static float magnitudeSquared( Vector2D v )
{
return v.magnitudeSquared();
}
public static float normalize( Vector2D v )
{
float length = v.magnitude();
float invMag = 1.0f/length;
if( length <= EPSILON ) return 0.0f;
v.x *= invMag;
v.y *= invMag;
return length;
}
public static float dot( Vector2D a, Vector2D b )
{
return ( (a.x * b.x) + (a.y * b.y) );
}
public static Vector2D Projection( Vector2D u, Vector2D v )
{
float dotUV = dot(u,v);
float dotUU = dot(u,u);
u.scale( dotUV/dotUU );
return u;
}
public static Vector2D Normal( Vector2D v, boolean side )
{
return ( side == false ) ? new Vector2D( -v.y, v.x ) : new Vector2D( v.y, -v.x );
}
public static Vector2D Normal( Vector2D v1, Vector2D v2, boolean side )
{
Vector2D v = new Vector2D( v2.x - v1.x, v2.y - v1.y );
return ( side == false ) ? new Vector2D( -v.y, v.x ) : new Vector2D( v.y, -v.x );
}
public static float Distance( Vector2D a, Vector2D b )
{
Vector2D d = new Vector2D( a.x - b.x, a.y - b.y );
return d.magnitude();
}
public static float angleBetween( Vector2D a, Vector2D b )
{
return (float)(Math.atan2(b.y - a.y, b.x - a.x));
}
public static Vector2D reflect( Vector2D v, Vector2D n )
{
float dot = (v.x * n.x) + (v.y * n.y);
Vector2D n2 = new Vector2D( n.x * -2.0f, n.y * -2.0f );
n2.scale(dot);
n2.x += v.x;
n2.y += v.y;
return n2;
}
public static Vector2D midPoint( Vector2D a, Vector2D b )
{
return new Vector2D( (b.x - a.x)/2.0f, (b.y - a.y)/2.0f );
}
public static Vector2D randomVector( float maxX, float maxY )
{
return new Vector2D( (float)(Math.random() * maxX), (float)(Math.random() * maxY) );
}
}
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