//    Instruction Example :      track.key.material.alpha.level.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)
        @material=material.create ()

        material.alpha.mode.set (@material,MATERIAL_ALPHABLEND)
        material.alpha.level.set (@material,50)
        mesh.material.set (@cube,@material,MATERIAL_BOTHSIDE)
        mesh.cull.mode.set (@cube,MESH_CULLNONE)
        mesh.display (@cube)

        @track=track.create (TRACK_LOOP|TRACK_PINGPONG)
          track.key.set (0)
          track.key.material.alpha.level.set (50)
          track.key.set (5)
          track.key.material.alpha.level.set (255)
        track.end ()

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

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

        keyboard.wait ()

        script.stop ()