<p>make opengl behave like you are drawing in 2d.</p>
<code>
def glEnable2D():
    """ make opengl behave like you are drawing in 2d.
    """
    vPort = glGetIntegerv(GL_VIEWPORT)

    glMatrixMode(GL_PROJECTION)
    glPushMatrix()
    glLoadIdentity()

    glOrtho(0, vPort[2], 0, vPort[3], -1, 1)
    glMatrixMode(GL_MODELVIEW)
    glPushMatrix()
    glLoadIdentity()


def glDisable2D():
   """ Use when you've finished drawing in 2D.
   """
   glMatrixMode(GL_PROJECTION)
   glPopMatrix()
   glMatrixMode(GL_MODELVIEW)
   glPopMatrix()

</code>