import traer.physics.*;
import hypermedia.video.*;


OpenCV opencv;

// contrast/brightness values
int contrast_value    = 0;
int brightness_value  = 0;


Particle mouse, b, c;
ParticleSystem physics;

void setup()
{
  size( 400, 400 );
  frameRate( 24 );
  smooth();
  ellipseMode( CENTER );
  noStroke();
  noCursor();
  
  opencv = new OpenCV( this );
    opencv.capture( width, height );                   // open video stream
    opencv.cascade( OpenCV.CASCADE_FRONTALFACE_ALT );  // load detection description, here-> front face detection : "haarcascade_frontalface_alt.xml"


  
  physics = new ParticleSystem( 0, 0.1 );
  mouse = physics.makeParticle();
  mouse.makeFixed();
  b = physics.makeParticle( 1.0, random( 0, width ), random( 0, height ), 0 );
  c = physics.makeParticle( 1.0, random( 0, width ), random( 0, height ), 0 );
  
  physics.makeAttraction( mouse, b, 10000, 10 );
  physics.makeAttraction( mouse, c, 10000, 10 );
  physics.makeAttraction( b, c, -10000, 5 );
}

void draw()
{
   background( 255 );
   opencv.read();
   opencv.flip( OpenCV.FLIP_HORIZONTAL);
    opencv.convert( GRAY );
    opencv.contrast( contrast_value );
    opencv.brightness( brightness_value );

    // proceed detection
    Rectangle[] faces = opencv.detect( 1.2, 2, OpenCV.HAAR_DO_CANNY_PRUNING, 40, 40 );

    // display the image
    image( opencv.image(), 0, 0 );

    // draw face area(s)
    noFill();
    stroke(255,0,0);
    for(int i = 0; i < faces.length; i++) {
        rect(faces[i].x, faces[i].y, faces[i].width, faces[i].height); 
    }
  
  if (faces.length > 0) {
  mouse.moveTo( faces[0].x,  faces[0].y, 0 );
  } else { 
    mouse.moveTo( 200,  200, 0 );
  }
  handleBoundaryCollisions( b );
  handleBoundaryCollisions( c );
  physics.tick();

 
  
  fill( 255, 0, 0 );
  ellipse( mouse.position().x(), mouse.position().y(), 35, 35 );

  
  fill( 0, 255, 0 );
  ellipse( b.position().x(), b.position().y(), 35, 35 );
   
  fill( 0, 0, 255 );
  ellipse( c.position().x(), c.position().y(), 35, 35 );
}

// really basic collision strategy:
// sides of the window are walls
// if it hits a wall pull it outside the wall and flip the direction of the velocity
// the collisions aren't perfect so we take them down a notch too
void handleBoundaryCollisions( Particle p )
{
  if ( p.position().x() < 0 || p.position().x() > width )
    p.setVelocity( -0.9*p.velocity().x(), p.velocity().y(), 0 );
  if ( p.position().y() < 0 || p.position().y() > height )
    p.setVelocity( p.velocity().x(), -0.9*p.velocity().y(), 0 );
  p.moveTo( constrain( p.position().x(), 0, width ), constrain( p.position().y(), 0, height ), 0 ); 
}

public void stop() {
    opencv.stop();
    super.stop();
}