A visualisation of a four part round of Frere Jaques played by Sonic Pi 3 and a processing sketch, linked by OSC messages. They should both be run on the same computer. A video of the project is at https://youtu.be/w89G0dN2BM0

visualfrerejaques.pd

//Processing sketch to display Frere Jacques
//4 part round played in Sonic Pi 3
//control via OSC messages sent from Sonic Pi
//written by Robin Newman december 23rd 2017

import oscP5.*;
import netP5.*;

OscP5 oscP5;
NetAddress myRemotelocation;
//declare variables
int[] circle_colora = new int[3];
int[] circle_colorb = new int[3];
int[] circle_colorc = new int[3];
int[] circle_colord = new int[3];
float rada,radb,radc,radd;
int na,nb,nc,nd;
int chana,chanb,chanc,chand;


void setup() {
  size(400,400);
  frameRate(30);
  oscP5 = new OscP5(this,8000); //set up osc connection, localhost port 8000
}

void draw() {
  smooth();
  background(0);
  //set fill colour and draw ellipse for each part (channel)
  fill(circle_colora[0],circle_colora[1],circle_colora[2]);
  ellipse(200+chana*9,388-na,20*rada*2,20*rada*2);
    fill(circle_colorb[0],circle_colorb[1],circle_colorb[2]);
  ellipse(200+chanb*9,388-nb,20*radb*2,20*radb*2);
    fill(circle_colorc[0],circle_colorc[1],circle_colorc[2]);
  ellipse(200+chanc*9,388-nc,20*radc*2,20*radc*2);
    fill(circle_colord[0],circle_colord[1],circle_colord[2]);
  ellipse(200+chand*9,388-nd,20*radd*2,20*radd*2);
}

void  mousePressed(){
  
}

void oscEvent(OscMessage theOscMessage){
  
  if (theOscMessage.checkAddrPattern("/na")==true) //deal with osc "/na"
  {
    na = theOscMessage.get(0).intValue();
  }
  if (theOscMessage.checkAddrPattern("/colora")==true) //deal with osc "/colora"
  {
    
    circle_colora[0]= theOscMessage.get(0).intValue();
    circle_colora[1]= theOscMessage.get(1).intValue();
    circle_colora[2]= theOscMessage.get(2).intValue();
  }
  if (theOscMessage.checkAddrPattern("/rada")==true) //deal with osc "/rada"
  {
    rada= theOscMessage.get(0).floatValue();
  }
  if (theOscMessage.checkAddrPattern("/chana")==true) //deal with osc "/chana"
  {
    chana= theOscMessage.get(0).intValue();
  }
  //repeat osc parsing for channesl b,c and d
    if (theOscMessage.checkAddrPattern("/nb")==true)
  {
    nb = theOscMessage.get(0).intValue();
  }
  if (theOscMessage.checkAddrPattern("/colorb")==true)
  {
    circle_colorb[0]= theOscMessage.get(0).intValue();
    circle_colorb[1]= theOscMessage.get(1).intValue();
    circle_colorb[2]= theOscMessage.get(2).intValue();
  }
  if (theOscMessage.checkAddrPattern("/radb")==true)
  {
    radb= theOscMessage.get(0).floatValue();
  }
  if (theOscMessage.checkAddrPattern("/chanb")==true)
  {
    chanb= theOscMessage.get(0).intValue();
  }
  
    if (theOscMessage.checkAddrPattern("/nc")==true)
  {
    nc = theOscMessage.get(0).intValue();
  }
  if (theOscMessage.checkAddrPattern("/colorc")==true)
  {
    circle_colorc[0]= theOscMessage.get(0).intValue();
    circle_colorc[1]= theOscMessage.get(1).intValue();
    circle_colorc[2]= theOscMessage.get(2).intValue();
  }
  if (theOscMessage.checkAddrPattern("/radc")==true)
  {
    radc= theOscMessage.get(0).floatValue();
  }
  if (theOscMessage.checkAddrPattern("/chanc")==true)
  {
    chanc= theOscMessage.get(0).intValue();
  }
  
    if (theOscMessage.checkAddrPattern("/nd")==true)
  {
    nd = theOscMessage.get(0).intValue();
  }
  if (theOscMessage.checkAddrPattern("/colord")==true)
  {
    circle_colord[0]= theOscMessage.get(0).intValue();
    circle_colord[1]= theOscMessage.get(1).intValue();
    circle_colord[2]= theOscMessage.get(2).intValue();
  }
  if (theOscMessage.checkAddrPattern("/radd")==true)
  {
    radd= theOscMessage.get(0).floatValue();
  }
  if (theOscMessage.checkAddrPattern("/chand")==true)
  {
    chand= theOscMessage.get(0).intValue();
  }
}
  

VisualFrereJaques.rb

#Frere jaques with visualization in Processing
#written by Robin Newman, December 23rd 2017
#info from Sonic Pi transmitted in OSC messages to drive the processing sketch
#A 4 part round is played, and each part is represented by a separate column
#the colour of each part varies with pitch as does the vertical postion of each note
#The radius of each "note" depends on its duration.
nmax=2 #number of iterations of Frère Jaques played
use_osc_logging true
#note and duration data for Frère Jaques
nf=[:c4,:d4,:e4,:c4]*2+[:e4,:f4,:g4]*2+[:g4,:a4,:g4,:f4,:e4,:c4]*2+[:c4,:g3,:c4]*2
df=[1,1,1,1,1,1,1,1,1,1,2,1,1,2,0.5,0.5,0.5,0.5,1,1,0.5,0.5,0.5,0.5,1,1,1,1,2,1,1,2]
use_bpm 180
with_fx :reverb,room: 0.8,mix: 0.6 do #add reverb for interest
  use_osc "localhost",8000 #link to processing sketch on same machine. Can be on external machine too
  live_loop :notes do #first part
    use_synth :pulse #differnt synth for each part
    use_bpm 180
    nv = nf.ring.tick #select each note in turn
    rel=df.ring.look #select corresponding duration
    play nv,release: rel,amp: 0.2 #play note with release set by duration
    osc "/chana",-18 #send channel position
    osc "/na",(note(nv)-48)*16 #send scaled note info to set vertical pos
    osc "/rada",rel.to_f #send rel value to set radius
    osc "/colora",128,(note(nv)-48)*16,0 #send colour info related to pitch
    sleep df.ring.look #sleep for durtation of note
    stop if look >= (df.length*nmax-1)
  end
  #subesequent parts identical apart from synth, channel, color setting
  live_loop :notes2,delay: 8 do #secnd part delayed 8 beats
    use_synth :tri
    use_bpm 180
    nv = nf.ring.tick
    rel=df.ring.look
    play nv,release: rel,amp: 0.2
    osc "/chanb",-6
    osc "/nb",(note(nv)-48)*16
    osc "/radb",rel.to_f
    osc "/colorb",0,128,(note(nv)-48)*16
    sleep df.ring.look
    stop if look >= (df.length*nmax-1)
  end
  
  live_loop :notes3,delay: 16 do #third part delayed 16 beats
    use_synth :prophet
    use_bpm 180
    nv = nf.ring.tick
    rel=df.ring.look
    play nv,release: rel,amp: 0.2
    osc "/chanc",6
    osc "/nc",(note(nv)-48)*16
    osc "/radc",rel.to_f
    osc "/colorc",(note(nv)-48)*16,0,128
    sleep df.ring.look
    stop if look >= (df.length*nmax-1)
  end
  
  live_loop :notes4,delay: 24 do #fourth part delayed 24 beats
    use_synth :saw
    use_bpm 180
    nv = nf.ring.tick
    rel=df.ring.look
    play nv,release: rel,amp: 0.2
    osc "/chand",18
    osc "/nd",(note(nv)-48)*16
    osc "/radd",rel.to_f
    osc "/colord",(note(nv)-48)*16,128,0
    sleep df.ring.look
    stop if look >= (df.length*nmax-1)
  end
end