theremin-pi/theremin/lib/fluidsynth.rb

# -*- ruby -*-
# vim: set noet sta sw=4 ts=4 :

require 'socket'
require 'configurability'
require 'loggability'


# Communicate with a running FluidSynth daemon via it's TCP socket API.
#
class FluidSynth
	extend Configurability,
		Loggability

	# The default host for the fluidsynth server.
	DEFAULT_HOST = 'localhost'

	# The default port for the fluidsynth server.
	DEFAULT_PORT = 9800


	# Loggability API
	log_as :fluidsynth

	# Configuration API
	#
	configurability( :fluidsynth ) do

		##
		# How many simultaneous notes can play.  Keep low for better CPU.
		setting :polyphony, default: 6

		##
		# Reverb amount.
		setting :reverb_size, default: 0.9

		##
		# Reverb gain level.
		setting :reverb_gain, default: 0.7

		##
		# Chorus depth.
		setting :chorus_depth, default: 64.0

		##
		# Chorus gain level.
		setting :chorus_gain, default: 1.5
	end


	### Instance a new fluidsynth interface.
	###
	def initialize( host=DEFAULT_HOST, port=DEFAULT_PORT )
		@host = host
		@port = port
		@lastnote = nil
		@velocity = 80
	end

	# The TCP socket to fluidsynth.
	attr_reader :socket

	# The previous note played, to enable glides.
	attr_reader :lastnote

	# The current velocity to play new notes at.
	attr_accessor :velocity


	### Open the TCP socket to the synth and perform initial setups.
	###
	def connect
		@socket = TCPSocket.new( @host, @port )

		self.setup_effects
		self.polyphony( self.class.polyphony )
	end


	### Setup polyphony amount.
	###
	def polyphony( val )
		self.send "synth.polyphony #{val}"
	end


	### Stop all notes and reset effects.
	###
	def panic
		self.send "reset"
	end


	### Alter the default volume.
	###
	def gain( level )
		self.send "gain #{level}"
	end


	### Select a loaded soundfont and instrument by index.
	### (Always using channel 0.)
	###
	def instrument( font_idx, instrument_idx )
		self.send "select 0 #{font_idx} 0 #{instrument_idx}"
	end


	### Turn glide (portamento) on or off.  Val is an integer that
	### represents 128ms.  4 == 512ms.
	###
	def glide( val )
		if val.zero?
			self.send "cc 0 68 0"
			self.send "cc 0 65 0"
			self.send "cc 0 5 0"
		else
			self.send "setlegatomode 0 1"
			self.send "cc 0 68 127" # legato
			self.send "cc 0 65 127" # portamento
			self.send "cc 0 5 #{val}"
		end
	end


	### Play a midi +note+ at +velocity+, then silence the previous note.
	### (This allows portamento to function if enabled.)
	###
	def playnote( note, velocity=self.velocity )
		return if @lastnote == note
		self.send "noteon 0 #{note} #{velocity}"
		self.stopnote
		@lastnote = note
	end


	### Silences the previous note played.
	###
	def stopnote
		return unless @lastnote
		self.send "noteoff 0 #{@lastnote}"
	end


	### Loads a resource (sf2, etc) from +path+.
	###
	def load( path )
		self.send "load #{path}"
	end


	### Enable/disable reverb.
	###
	def reverb( toggle=true )
		toggle = toggle ? 1 : 0
		self.send "set synth.reverb.active #{toggle}"
	end


	### Enable/disable chorus.
	###
	def chorus( toggle=true )
		toggle = toggle ? 1 : 0
		self.send "set synth.chorus.active #{toggle}"
	end


	#########
	protected
	#########

	### Initial effect setup.
	###
	def setup_effects
		self.send "set synth.reverb.room-size 0.9"
		self.send "set synth.reverb.level 0.7"
		self.send "set synth.chorus.level 1.5"
		self.send "set synth.chorus.depth 64.0"
	end


	### Issue a command to the synth, after possible logging.
	###
	def send( cmd )
		self.log.debug( cmd )
		self.socket.puts( cmd )
	end
end