rad=5e-3  # the radius of a point 
zoom_scale_step=math.pow(2.,1./20.) #scaling factor used for zooming in






    #######################
    #
    
    #Now... WHEN AN OBJECT IS PICKED,
    #TRANSLATE THE scene.center TO THE OBJECT'S POSITION, AND ZOOM

    if scene.mouse.events:
        MOUSE_EVENT=scene.mouse.getevent()
        print MOUSE_EVENT.press, MOUSE_EVENT.pos
        if (MOUSE_EVENT.press=='left' or
           MOUSE_EVENT.press=='right' or MOUSE_EVENT.press=='middle'):
            if MOUSE_EVENT.press=='left': #ZOOM IN
                scale_factor=2.
                scale_step=zoom_scale_step
            elif MOUSE_EVENT.press=='right': #ZOOM OUT
                scale_factor=1./2.
                scale_step=1./zoom_scale_step
            else: #NO ZOOM
                scale_factor=1.0
                scale_step=1.0

            target=MOUSE_EVENT.pos
            step=(target-scene.center)/20.
            for i in arange(0,20):
                    rate(50)
                    scene.center +=step
                    scene.scale *= scale_step  #(zoom_scale_step**20.=2.0)

            rad /= scale_factor
            for o in scene.objects:
                o.radius = rad
    #
    #######################