event propagate

    @input_manager.when :event_received do |event|
      case event
      when KeyDownEvent
        case event.key
        when K_SPACE
          ship.warp vec2(300,300)
        when K_LEFT
          ship.moving_left = true
        when K_RIGHT
          ship.moving_right = true
        when K_UP
          ship.moving_forward = true
        when K_DOWN
          ship.moving_back = true
        end
      when KeyUpEvent
        case event.key
        when K_LEFT
          ship.moving_left = false
        when K_RIGHT
          ship.moving_right = false
        when K_UP
          ship.moving_forward = false
        when K_DOWN
          ship.moving_back = false
        end
      end  
    end