//    Instruction Example :      track.camera.roll.interpolation.set (long)

        screen.resolution.set (512,384)

        screen.set (BACK)
          pattern.display ("avo\bubble.gif")
        screen.end ()

        @camera=camera.create (100,70,-200,0,0,0)
        @viewport=viewport.create ()
        viewport.camera.set (@viewport,@camera)
        viewport.display (@viewport)

        @cube=mesh.cube.create (100)
        mesh.display (@cube)

        @track=track.create (TRACK_LOOP)
          track.key.set (0)
          track.key.camera.roll.set (90)
          track.key.set (1)
          track.key.camera.roll.set (-90)
          track.key.set (2)
          track.key.camera.roll.set (90)
        track.end ()

        @sequence=sequence.play (@track,@camera)

        screen.set (FRONT)
          text.display ("Press a key to change interpolation.",CENTER,10)
        screen.end ()

        keyboard.wait ()

        sequence.free (@sequence)

        @track=track.create (TRACK_LOOP)
          track.camera.roll.interpolation.set (INTERP_TCBSPLINE)
          track.key.set (0)
          track.key.camera.roll.set (90)
          track.key.set (1)
          track.key.camera.roll.set (-90)
          track.key.set (2)
          track.key.camera.roll.set (90)
        track.end ()

        @sequence=sequence.play (@track,@camera)

        screen.set (FRONT)
          text.display ("Press a key to exit.",CENTER,350)
        screen.end ()

        keyboard.wait ()

        script.stop ()