# File lib/as_transform2d.rb, line 41
  def self.ortho(left, right, bottom, top)
                a = 2.0/Float(right - left)
                b = -Float(right + left)/Float(right - left)
                c = 2.0/Float(top - bottom)
                d = -Float(top + bottom)/Float(top - bottom)
                
                AS::Transform2D[
                        [a, 0, 0, b],
                        [0, c, 0, d],
                        [0, 0, 1, 0],
                        [0, 0, 0, 1],
                ]
  end