Ruby Vector2D

A 2D Vector for Ruby. This is for the Koch snowflake and future 2D examples. Feel free to let me know how I can improve it, or where I can find a good third-party implementation.

Writing geometry classes has been one of my biggest frustrations because of the different implementations, or lack thereof, in the various graphics packages. As a result of this, my first instinct when picking up a new framework is figuring out what geometry is supported and the operations that are available.

A good geometry class for points, vectors, lines, shapes, etc., can save you a lot of headache trying to remember how to do a certain geometrical operation, and focus instead on putting these operations together.

# Use this so glVertex works.
require 'opengl'

class Vector
 attr_accessor :x, :y;

 def initialize(x,y)
  self.x = x
  self.y = y
 end

 def gl_vertex
  GL::Vertex2f(x,y)
 end

 def normal
  Vector.new(-@y,@x)
 end

 def normalize
  before_length = length
  return if before_length == 0
  @x /= before_length
  @y /= before_length
 end

 def length
  return Math.sqrt(@x*@x + @y*@y)
 end

 def reverse
  @x = -@x
  @y = -@y
 end

 def add_vector(v)
  @x += v.x
  @y += v.y
 end

 def sub_vector(v)
  @x -= v.x
  @y -= v.y
 end

 def multiply(scalar)
  @x *= scalar
  @y *= scalar
 end

 def divide(scalar)
  @x = @x / (1.0 * scalar)
  @y = @y / (1.0 * scalar)
 end

 def Vector.copy(p)
  return Vector.new(p.x,p.y)
 end

 def Vector.between(p1,p2)
  between = Vector.new(p2.x,p2.y)
   between.sub_vector(p1)
  return between
 end

 def to_s
  "#{x}, #{y}"
 end

 def Vector.midpoint(p1, p2)
  midpoint = Vector.new(p1.x,p1.y)
  midpoint.add_vector(p2)
  midpoint.divide(2.0)
  return midpoint
 end
end