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Το πρωτόκολλο επικοινωνίας OSC είναι το πλέον καθιερωμένο για εφαρμογές πολυμέσων. Η βιβλιοθήκη που μας δίνει την δυνατότητα στην Processing, να στέλνουμε και να λαμβάνουμε OSC μηνύματα είναι η oscP5.

• Useful links
  • http://www.sojamo.de/libraries/oscP5/reference/index.html
• Βασικό sketch για OSC communication

/**
 * oscP5plug by andreas schlegel
 * example shows how to use the plug service with oscP5.
 * the concept of the plug service is, that you can
 * register methods in your sketch to which incoming 
 * osc messages will be forwareded automatically without 
 * having to parse them in the oscEvent method.
 * that a look at the example below to get an understanding
 * of how plug works.
 * oscP5 website at http://www.sojamo.de/oscP5
 */

import oscP5.*;
import netP5.*;

OscP5 oscP5;
NetAddress myRemoteLocation;

void setup() {
  size(400,400);
  frameRate(25);
  /* start oscP5, listening for incoming messages at port 12000 */
  oscP5 = new OscP5(this,12000);
  
  /* myRemoteLocation is a NetAddress. a NetAddress takes 2 parameters,
   * an ip address and a port number. myRemoteLocation is used as parameter in
   * oscP5.send() when sending osc packets to another computer, device, 
   * application. usage see below. for testing purposes the listening port
   * and the port of the remote location address are the same, hence you will
   * send messages back to this sketch.
   */
  myRemoteLocation = new NetAddress("127.0.0.1",57120);
  
  /* osc plug service
   * osc messages with a specific address pattern can be automatically
   * forwarded to a specific method of an object. in this example 
   * a message with address pattern /test will be forwarded to a method
   * test(). below the method test takes 2 arguments - 2 ints. therefore each
   * message with address pattern /test and typetag ii will be forwarded to
   * the method test(int theA, int theB)
   */
  oscP5.plug(this,"test","/test");
}


public void test(int theA, int theB) {
  println("### plug event method. received a message /test.");
  println(" 2 ints received: "+theA+", "+theB);  
}


void draw() {
  background(0);
}


void mousePressed() {
  /* createan osc message with address pattern /test */
  OscMessage myMessage = new OscMessage("/test");
  
  myMessage.add(123); /* add an int to the osc message */
  myMessage.add(456); /* add a second int to the osc message */

  /* send the message */
  oscP5.send(myMessage, myRemoteLocation); 
}

• Κώδικας στο SuperCollider για αποστολή και λήψη μηνυματων.

//:OSC Responder
OSCresponder(nil, "/test", { |t, r, msg| msg[1].postln;}).add; //Create a Responder

n = NetAddr("127.0.0.1", 12000);
n.sendMsg("/test", 1,2);

Για δημιουργία εφαρμογών στην Processing που χρησιμοποιούν Όραση Υπολογιστών, χρησιμοποιούμε την βιβλιοθήκη OpenCV.

• Βασικό sketch για OpenCV
  

  Ένα απλό sketch που κάνει blob detection είναι το ακόλουθο:

  import hypermedia.video.*;
  import java.awt.*; 
  
  OpenCV opencv;
  
  int w = 320;
  int h = 240;
  int threshold = 80;
  boolean find=true;
  PFont font;
  
  void setup() {
      size( w*2+30, h*2+30 );
      opencv = new OpenCV( this );
      opencv.capture(w,h);
      font = loadFont( "AndaleMono.vlw" );
      textFont( font );
      println( "Drag mouse inside sketch window to change threshold" );
      println( "Press space bar to record background image" );
  }
  
  void draw() {
      background(0);
      opencv.read();
      opencv.absDiff();
      opencv.threshold(threshold);
      image( opencv.image(OpenCV.GRAY), 20+w, 20+h ); // absolute difference image
      
      Blob[] blobs = opencv.blobs( 400, w*h/3, 1, false );
      noFill();
      for( int i=0; i<blobs.length; i++ ) {
          Point centroid = blobs[i].centroid;
          println(centroid.y);
      }
  }
  
  void keyPressed() {
      if ( key==' ' ) opencv.remember();
  }
  
  void mouseDragged() {
      threshold = int( map(mouseX,0,width,0,255) );
  }
  
  public void stop() {
      opencv.stop();
      super.stop();
  }
  

• Links
  
  • Processing Tutorials: Getting Started with Video Processing via OpenCV
    

Η ProcessingJS είναι η μικρή αδελφή της Processing (P5).