lighttroupe/luz

module EngineDMX
    def with_dmx(channel_offset = 1)
        init_dmx if @dmx.nil?
        if @dmx
            @dmx.with_starting_channel(channel_offset) {
                yield @dmx
            }
        end
    end

private

    DMX_CHANNEL_COUNT = 256        # for ~88 hz refresh rate
    def init_dmx
        require 'dmx'

        # TODO: find a better method of finding the device
        @dmx ||= DMX.new("/dev/ttyUSB0", DMX_CHANNEL_COUNT) rescue nil
        @dmx ||= DMX.new("/dev/ttyUSB1", DMX_CHANNEL_COUNT) rescue nil
        @dmx ||= DMX.new("/dev/ttyUSB2", DMX_CHANNEL_COUNT) rescue nil

        if @dmx
            puts "DMX Opened"

            # Send at end of frame and retry dmx_init
            self.on_frame_end { @dmx.send ; @dmx.clear } if @dmx

            # turn off lights when quiting
            ObjectSpace.define_finalizer(self, proc { @dmx.clear ; @dmx.send }) if @dmx
        else
            @dmx = false        # mark as init failed

            # retry dmx_init on reload
            self.on_reload { @dmx = nil if @dmx === false }
        end
    end
end