Tutorial: Playing Sounds in a Separate Thread

--D. Thiebaut (talk) 17:54, 10 January 2014 (EST)

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This tutorial present a simple Processing sketch (developed using Processing's own IDE, and not Eclipse) that uses a thread to play sounds. Two circles bounce inside a rectangular box and a "beep" is generated every time they touche the boundaries.

The Main Sketch

// NoisyBalls.pde
// D. Thiebaut
// A sketch that animates two balls bouncing off the walls.
// It uses the minim library to play sounds.
import ddf.minim.signals.*;
import ddf.minim.*;
import ddf.minim.analysis.*;
import ddf.minim.ugens.*;
import ddf.minim.effects.*;

// the coordinates and speeds of two circles
int x1, y1, deltax1, deltay1;
int x2, y2, deltax2, deltay2;

// the thread that plays the sounds...
MyThread sonar;

void setup() {
    // create the sound player
    Minim minim = new Minim(this);
    AudioPlayer player = minim.loadFile( "sonar.wav" );

    // define geometry and window
    textAlign(CENTER);
    size( 600, 400 );
    smooth();

    // position and activate the two circles
    x1 = width/2;
    y1 = height/2;
    deltax1 = 4;
    deltay1 = 3;

    x2 = width/2;
    y2 = height/2;
    deltax2 = 2;
    deltay2 = 5;

    // create the thread and start it.
    sonar = new MyThread( minim, player );
    sonar.start();
}
  

void draw() {
    // erase window
    background( 0 );

    // put message in middle
    text( "Press any key to quit...", width/2, height/2 );

    // show the two moving balls
    ellipse( x1, y1, 20, 20 );
    ellipse( x2, y2, 20, 20 );

    // update positions of Ball 1, and if necessary change direction of movement
    x1 += deltax1;
    if ( x1 < 0 || x1 > width ) { 
      deltax1 = -deltax1;
      // beep! 
      sonar.playNow();  
    }
    y1 += deltay1;
    if ( y1 < 0 || y1 > height ) { 
      deltay1 = -deltay1; 
      // beep!
      sonar.playNow();
    }

    // update positions of Ball 2, and if necessary change direction of movement
    x2 += deltax2;
    if ( x2 < 0 || x2 > width ) { 
      deltax2 = -deltax2; 
      sonar.playNow();
    }
    y2 += deltay2;
    if ( y2 < 0 || y2 > height ) { 
      deltay2 = -deltay2; 
      sonar.playNow();
    }
}

// keyPressed():  if a key is pressed, simply stop the sketch
void keyPressed() {
  // set sonar to stop running
  sonar.quit();

  // wait 500 ms (1/2 sec)
  try {
    Thread.sleep( 500 );
  }
    catch ( InterruptedException e ) {
  }

  // then exit completely
  exit( );
}