lighttroupe/luz

#
# Sliders (also knobs, and any other 0.0 -> 1.0 inputs)
#
module EngineSliders
    include Callbacks

    callback :new_slider

    attr_reader :seen_sliders_list

    def init_sliders
        @slider_values = Hash.new(0.0)
        @slider_delayed_updates = Hash.new
        @slider_values_last_update_frame = Hash.new
        @seen_sliders_list = []
    end

    def slider_tick
        @slider_delayed_updates.each_pair { |k, v| on_slider_change(k, v, delayed=true) }
        @slider_delayed_updates.clear
    end

    def slider_grab(&proc)
        @slider_grab_proc = proc
    end
    def cancel_slider_grab
        @slider_grab_proc = nil
    end

    def on_slider_change(name, value, delayed=false)
        return unless name
        on_new_slider(name)

        # special-case one type of change:
        # - 2+ slider changes in one frame
        # - second value goes to 0.0
        # this prevents a quick "a=1,a=0" from being lost
        frame_number = $env[:frame_number]
        if (delayed == false) && (@slider_values_last_update_frame[name] == frame_number) && (value == 0.0)
            @slider_delayed_updates[name] = value
        else
            @slider_values[name] = value
            @slider_values_last_update_frame[name] = frame_number
        end

        # Send signal if GUI is listening (for auto-mapping inputs via Record button)
        if @slider_grab_proc
            @slider_grab_proc = nil if @slider_grab_proc.call(name)        # true = eaten
        end
    end

    def slider_value(name)
        return 0.0 unless name
        on_new_slider(name)
        @slider_values[name]
    end

private

    def on_new_slider(name)
        return if @seen_sliders_list.include?(name)
        raise ArgumentError unless name
        @seen_sliders_list << name
        @seen_sliders_list.sort!
    end
end