fading text in gamebox

gamebox_fade.rb

define_behavior :fades do
  requires :director
  setup do # |opts| 
    fade_out_time = 3_000
    actor.has_attributes total_fade_time: fade_out_time, fade_time: fade_out_time

    director.when :update do |time_ms, secs|
      actor.fade_time -= time_ms
      alpha = 255 * actor.fade_time / actor.total_fade_time
      actor.remove if actor.fade_time <= 0
      # must set color to a different array to trigger the change event.. 
      actor.color = actor.color[0..2] + [alpha]
    end

    reacts_with :remove
  end

  helpers do
    def remove
      director.unsubscribe_all self
    end
  end
end


define_stage :demo do
  # gamebox usually encourages the adding of behaviors from within another behavior, to do it from the stage we need:
  requires :behavior_factory

  curtain_up do
    @text = create_actor :label, x: 10, y:30, text: "In the beginning"

    timer_manager.add_timer :turn_the_page, 1_000, false do
      behavior_factory.add_behavior @text, :fades #, fade_time: 3_000      ## opts can be passed in here
    end

    @text.when :remove_me do
      fire :next_stage
    end
  end
end