require 'opengl'
require 'glut'
require 'mathn'

def transformPoint(screenX, screenY)
  x = (screenX - ($screenWidth / 2.0)) / ($screenWidth / 2.0)
  y = -1 * (screenY - ($screenHeight / 2.0)) / ($screenHeight / 2.0)
  return Point2d.new(x, y)
end

def init
   GL.Enable(GL::LINE_SMOOTH);
   GL.Enable(GL::BLEND);
   GL.BlendFunc(GL::SRC_ALPHA, GL::ONE_MINUS_SRC_ALPHA);
   GL.Hint(GL::LINE_SMOOTH_HINT, GL::DONT_CARE);
   GL.LineWidth(0.1);
   GL.ClearColor(0.0, 0.0, 0.0, 0.0);
end

reshape = Proc.new {|w, h|
   GL.Viewport(0, 0, w, h);
   GL.MatrixMode(GL::PROJECTION);
   GL.LoadIdentity();
   if (w <= h) 
      GLU.Ortho2D(-1.0, 1.0, -1.0*h/w, 1.0*h/w);
   else 
      GLU.Ortho2D(-1.0*w/h, 1.0*w/h, -1.0, 1.0);
   end
   GL.MatrixMode(GL::MODELVIEW);
   GL.LoadIdentity();
}


GLUT.Init
GLUT.InitDisplayMode(GLUT::SINGLE | GLUT::RGB)
GLUT.InitWindowSize($screenWidth, $screenHeight)
GLUT.CreateWindow($0)
init
GLUT.ReshapeFunc($reshape)