require 'matrix'

#
# Extensions to built-in Ruby classes
#

class Matrix

  def self.rotation(angle)
		cos_a, sin_a = Math.cos(angle), Math.sin(angle)
		Matrix[ [cos_a, -sin_a], [sin_a, cos_a] ]
  end

  def self.reflection; Matrix[ [1,0], [0, -1] ]; end

end

class Array
  def to_s
    return self.inspect if not self[0].is_a? Float
    inject("[") {|p,q| p += sprintf(" %.1f",q)} + "]"
  end
end

class Vector

  def rotateBy radians; Matrix.rotation(radians) * self; end

  def reflection; Vector[@elements[X], -@elements[Y]]; end

  def reflectBy radians; reflection.rotateBy(radians); end

  def angle; Math.atan2(@elements[Y], @elements[X]); end

  def ratio; @elements[Y] / @elements[X]; end

  def area; @elements.inject(4) {|x,y| x*y}; end

  def within?(size)
    each2(size) { |self_i, size_i| return false if self_i.abs > size_i }
    true
  end

  def to_s; to_a.to_s; end

end

BOUNDS = Vector[1500.0, 1250.0]
SCREEN_SIZE = Vector[700.0, 500.0]
SCREEN_ORIGIN = SCREEN_SIZE * 0.5
SHELL_SIZE = Vector[2.0,2.0]
TANK_SIZE = Vector[10.0,15.0]
MUZZLE_SIZE = Vector[25.0,0.0]


Shoes.app do
  b = Vector[-500.0, 250.0]
  para b.to_s
end