GMU:Actors, Traces, Collectives/SS17/Tracking

import processing.video.*;
Capture video;
int x, y;
Mover [] mover = new Mover [20];

void setup() {

  size(640, 480);
  video = new Capture(this, width, height);
  video.start();
  for (int i = 0; i < mover.length; i++) {
    mover [i]=new Mover ();
  }
}

void draw() {
  if (video.available()) {
    video.read();
    image(video, 0, 0, width, height);
    int brightestX = 0; // X-coordinate of the brightest video pixel
    int brightestY = 0; // Y-coordinate of the brightest video pixel
    float brightestValue = 0; // Brightness of the brightest video pixel
    video.loadPixels();
    int index = 0;
    for (int y = 0; y < video.height; y++) {
      for (int x = 0; x < video.width; x++) {
        int pixelValue = video.pixels[index];
        float pixelBrightness = brightness(pixelValue);
        if (pixelBrightness > brightestValue) {
          brightestValue = pixelBrightness;
          brightestY = y;
          brightestX = x;
        }
        index++;
      }
    }
    for (int j = 0; j < mover.length; j++) {
      // Update the position
      mover[j].update(brightestX, brightestY);
      // Display the Mover
      mover[j].display();
    }
  }
}

// The Nature of Code
// Daniel Shiffman
// http://natureofcode.com

class Mover {

  // The Mover tracks position, velocity, and acceleration 
  PVector position;
  PVector velocity;
  PVector dir;
  // The Mover's maximum speed
  float topspeed;
  

  Mover() {
    // Start in the center
    position = new PVector(width/2,height/2);
    velocity = new PVector(0,0);
    topspeed = 5;
  }

  void update(float x, float y) {
    
    // Compute a vector that points from position to mouse
    PVector mouse = new PVector(x,y);
    PVector dir = PVector.sub(mouse,position);
    
    // Set magnitude of acceleration
    dir.setMag(0.3);
    
    // Velocity changes according to acceleration
    velocity.add(dir);
    
    // Limit the velocity by topspeed
    velocity.limit(topspeed);
    // position changes by velocity
    position.add(velocity);
  }

  void display() {
    stroke(0);
    strokeWeight(2);
    //fill(127);
    //ellipse(position.x,position.y,48,48);
    line (position.x,position.y, position.x+velocity.x,position.y+velocity.y);
  }

}