Animal!!!

I love this video from R.E.M:

And I was lucky enough to find the source code from this website:

http://processing.org/exhibition/works/starnursery/index_link.html

Here's the code:

// Star Nursery

// by Ryan Alexander at Motion Theory

// 

// Press tilde (~) to show the bounding circles

// Press the mouse to hide the video

// 

// Make sure to have your camera turned on before you run me!

// 

// Deep currents

// Like the sky

// Use no pentameter

// Mike Stipe is just this guy

int maxStars = 10000;

int nStars = 0;

Star stars[] = new Star[maxStars];

BImage basicStar, vidThumb;

boolean newFrame;

float brightest = 255;

float darkest = 0;

float brightX[][] = new float[8][6];

float brightY[][] = new float[8][6];

float brightVelX[][] = new float[8][6];

float brightVelY[][] = new float[8][6];

boolean firstFrame = true;

void setup()

{

  size(500, 375);

  background(0);

  basicStar = loadImage("pfx_star.gif");

  brightToAlpha(basicStar);

  beginVideo(width, height, 15);

  framerate(30);

  

  conceiveStars(300);

}

void loop()

{

  // Calibrate the video for next frame

  if(newFrame) {

    calibrateVideo();

    newFrame = false;

    firstFrame = false;

  }

  

  if(mousePressed) {

    background(0);

  } else {

    background(video);

  }

  noFill();

  stroke(255,0,0,40);

  for(int i=0; i < nStars; i++) {

    stars[i].update();

  }

  stroke(128,128,128,40);

  for(int i=0; i < nStars; i++) {

    stars[i].display();

  }

}

void mouseReleased()

{

  background(0);

}

void videoEvent()

{

  newFrame = true;

}

void conceiveStars(int n)

{

  n += nStars;

  for(int i=nStars; i < n; i++) {

    stars[i] = new Star(i, random(width), random(height), random(-5, 5), random(-5, 5));

  }

  nStars += n;

}

void calibrateVideo()

{

  vidThumb = video.copy(40, 30);

  float tempb = brightness(vidThumb.pixels[0]);

  brightest = tempb;

  darkest = tempb;

  for(int i=1; i < 1200; i++) {

    tempb = brightness(vidThumb.pixels[i]);

    if(tempb > brightest) {

      brightest = tempb;

    }

    if(tempb < darkest) {

      darkest = tempb;

    }

  }

  

  // Make sure that lightest is > darkest

  if(brightest <= darkest) brightest = darkest + 1;

  

  // Calculate the changes in general brightness

  float tempx, tempy, totalBright;

  int pxx, pxy;

  for(int j=0; j < 6; j++) {

    for(int i=0; i < 8; i++) {

      tempx = 0;

      tempy = 0;

      totalBright = 0;

      

      for(int jj=0; jj < 5; jj++) {

        for(int ii=0; ii < 5; ii++) {

          pxx = i*5 + ii;

          pxy = j*5 + jj;

          tempb = brightness(vidThumb.pixels[pxx + pxy * 40]);

          tempx += pxx * tempb;

          tempy += pxy * tempb;

          totalBright += tempb;

        }

      }

      

      // Adjust the general velocity of the brightness

      if(totalBright == 0) {  // Avoid divide by 0

        if(firstFrame) {

          brightX[i][j] = i * (width/8) + (width/16);

          brightY[i][j] = j * (height/6) + (height/12);

        }

      } else {

        tempx = (tempx / totalBright + .5) * (width / 40.0);

        tempy = (tempy / totalBright + .5) * (height / 30.0);

        if(firstFrame) {

          brightX[i][j] = tempx;

          brightY[i][j] = tempy;

        } else {

          brightX[i][j] += brightVelX[i][j];

          brightY[i][j] += brightVelY[i][j];

          brightVelX[i][j] = ((tempx - brightX[i][j]) - brightVelX[i][j]) * .2;

          brightVelY[i][j] = ((tempy - brightY[i][j]) - brightVelY[i][j]) * .2;

        }

      }

    }

  }

}

//      //

// Star //

//      //

class Star

{

  float x, y, xv, yv;

  float diameter, inside, minD, maxD;

  int id, age;

  boolean connected[] = new boolean[maxStars];

  float red, green, blue;

  Star(int iid, float ix, float iy, float ixv, float iyv)

  {

    x = ix; y = iy;

    xv = ixv; yv = iyv;

    id = iid;

    age = (int)random(500);

    minD = 20;

    maxD = 60;

  }

  void update()

  {

    // Decay the inside diameter

    if(inside > 0) inside -= 1;

    // React to video input

    if(x >= 0 && x < width && y >= 0 && y < height) {

      color tempPixel = video.pixels[(int)x + (int)y*width];

      // Diameter grows with brightness

      float multiplier = 255.0 / (brightest - darkest);

      float bright = constrain(((brightness(tempPixel) - darkest) * multiplier) / 255, 0, 1);

      float sizeMult = sin(age * .05) * .4 + .6;

      diameter += ( (((1 - bright) * (maxD - minD) + minD) * sizeMult) - diameter ) * .2;

      

      // Influence by movement of general brightness

      xv += brightVelX[(int)floor(x / (width/8.0))][(int)floor(y / (height/6.0))] * 1;

      yv += brightVelY[(int)floor(x / (width/8.0))][(int)floor(y / (height/6.0))] * 1;

    }

    // Check for new connections

    for(int i=0; i < nStars; i++) {

      if(i != id) {// && touching < 1 && stars[i].touching < 1) {  // If it's not me

         float xd = stars[i].x - x;

         float yd = stars[i].y - y;

         float diff = xd*xd + yd*yd;

         float radii = stars[i].diameter/2 + diameter/2;

         // If touching

         if(diff < radii*radii) {

           springAdd(stars[i].x, stars[i].y, radii);

           // Assimilate Velocity

           xv += (stars[i].xv - xv) * .01;

           yv += (stars[i].yv - yv) * .01;

           // Color changes with distance

           float dist = sqrt(diff);

           if(dist < 30) {

             stroke(255, ((30 - dist) * 6) * (min(inside, stars[i].inside) / 60));

             line(x, y, stars[i].x, stars[i].y);

           }

           if(!connected[i]) {

             inside += diameter / (maxD / 5);

             connected[i] = true;

           }

         } else {

           connected[i] = false;

         }

       }

     }

     inside = constrain(inside, 0, 60);

   }

   void display()

   {

     ellipseMode(CENTER_DIAMETER);

     if(keyPressed && key == '`') {

       ellipse(x, y, diameter, diameter);

     }

     if(inside > 1) {

       imageMode(CENTER_DIAMETER);

       tint(255, (inside-4)*64);

       push();

       translate(0,0,-1);

       image(basicStar, x, y, inside, inside);

       pop();

     }

     //line(x, y, x+xv, y+yv);

     x += xv;

     y += yv;

     // Constrain to screen

     float d2 = diameter/2;

     if(x < d2) { x = d2; }

     if(x > width - d2) { x = width - d2; }

     if(y < d2) { y = d2; }

     if(y > height - d2) { y = height - d2; }

     xv *= .8;

     yv *= .8;

     age++;

   }

   float dx, dy, mag, ext;

   void springAdd(float sx, float sy, float rest)

   {

     dx = sx - x;

     dy = sy - y;

     if(dx != 0 || dy != 0) {  // Prevent / by zero

       mag = sqrt(dx*dx + dy*dy);

       ext = mag - rest;

       xv += (dx / mag * ext) * .1;

       yv += (dy / mag * ext) * .1;

     }

   }

 }

 void brightToAlpha(BImage b)

 {

   b.format = RGBA;

   for(int i=0; i < b.pixels.length; i++) {

     b.pixels[i] = color(255,255,255,brightness(b.pixels[i]));

   }

 }

The only problem is that it was built for processing 1.0 and therefore there are a lot of changes that need to be made to the code to update it.

I was also lucky to find an updated version online from the following website:

http://processing.org/discourse/yabb2/YaBB.pl?num=1206398682


import processing.video.*;

// Star Nursery
// by Ryan Alexander at Motion Theory
//
// Press tilde (~) to show the bounding circles
// Press the mouse to hide the video
//
// Make sure to have your camera turned on before you run me!
//
// Deep currents
// Like the sky
// Use no pentameter
// Mike Stipe is just this guy

int maxStars = 10000;
int nStars = 0;
Star stars[] = new Star[maxStars];

PImage basicStar, vidThumb;

boolean newFrame;
float brightest = 255;
float darkest = 0;

float brightX[][] = new float[8][6];
float brightY[][] = new float[8][6];
float brightVelX[][] = new float[8][6];
float brightVelY[][] = new float[8][6];

boolean firstFrame = true;

Capture video;

void setup()
{
  size(800, 600);
  background(0);

  basicStar = loadImage("pfx_star.gif");
  brightToAlpha(basicStar);

  video = new Capture(this, width, height, 15);
  frameRate(30);
 
  conceiveStars(1000);
}

void captureEvent(Capture video) {
  video.read();
}

void draw()
{
  image(video, 0, 0);
  // Calibrate the video for next frame
  if(newFrame) {
    calibrateVideo();
    newFrame = false;
    firstFrame = false;
  }
 
 if(mousePressed) {
    background(0);
 } else {
   background(video);
 }

  noFill();
  stroke(255,0,0,40);
  for(int i=0; i < nStars; i++) {
    stars[i].update();
  }
  stroke(128,128,128,40);
  for(int i=0; i < nStars; i++) {
    stars[i].display();
  }
}

//void mouseReleased()
//{
 // background(0);
//}

void videoEvent()
{
  newFrame = true;
}

void conceiveStars(int n)
{
  n += nStars;
  for(int i=nStars; i < n; i++) {
    stars[i] = new Star(i, random(width), random(height), random(-5, 5), random(-5, 5));
  }
  nStars += n;
}

void calibrateVideo()
{
  vidThumb.copy(video, 0, 0 ,width, height, 0, 0, 40, 30);
  float tempb = brightness(vidThumb.pixels[0]);
  brightest = tempb;
  darkest = tempb;

  for(int i=1; i < 1200; i++) {
    tempb = brightness(vidThumb.pixels[i]);
    if(tempb > brightest) {
brightest = tempb;
    }
    if(tempb < darkest) {
darkest = tempb;
    }
  }
 
  // Make sure that lightest is > darkest
  if(brightest <= darkest) brightest = darkest + 1;
 
  // Calculate the changes in general brightness
  float tempx, tempy, totalBright;
  int pxx, pxy;
  for(int j=0; j < 6; j++) {
    for(int i=0; i < 8; i++) {
tempx = 0;
tempy = 0;
totalBright = 0;

for(int jj=0; jj < 5; jj++) {
 for(int ii=0; ii < 5; ii++) {
   pxx = i*5 + ii;
   pxy = j*5 + jj;
   tempb = brightness(vidThumb.pixels[pxx + pxy * 40]);
   tempx += pxx * tempb;
   tempy += pxy * tempb;
   totalBright += tempb;
 }
}
// Adjust the general velocity of the brightness
if(totalBright == 0) {  // Avoid divide by 0
 if(firstFrame) {
   brightX[i][j] = i * (width/8) + (width/16);
   brightY[i][j] = j * (height/6) + (height/12);
 }
} else {
 tempx = (tempx / totalBright + .5) * (width / 40.0);
 tempy = (tempy / totalBright + .5) * (height / 30.0);
 if(firstFrame) {
   brightX[i][j] = tempx;
   brightY[i][j] = tempy;
 } else {
   brightX[i][j] += brightVelX[i][j];
   brightY[i][j] += brightVelY[i][j];
   brightVelX[i][j] = ((tempx - brightX[i][j]) - brightVelX[i][j]) * .2;
   brightVelY[i][j] = ((tempy - brightY[i][j]) - brightVelY[i][j]) * .2;
 }
}
    }
  }
}


// //
// Star //
// //
class Star
{
  float x, y, xv, yv;
  float diameter, inside, minD, maxD;
  int id, age;

  boolean connected[] = new boolean[maxStars];

  float red, green, blue;

  Star(int iid, float ix, float iy, float ixv, float iyv)
  {
    x = ix; y = iy;
    xv = ixv; yv = iyv;
    id = iid;
    age = (int)random(500);

    minD = 20;
    maxD = 60;
  }

  void update()
  {
    // Decay the inside diameter
    if(inside > 0) inside -= 1;

    // React to video input
    if(x >= 0 && x < width && y >= 0 && y < height) {
color tempPixel = video.pixels[(int)x + (int)y*width];

// Diameter grows with brightness
float multiplier = 255.0 / (brightest - darkest);
float bright = constrain(((brightness(tempPixel) - darkest) * multiplier) / 255, 0, 1);
float sizeMult = sin(age * .05) * .4 + .6;
diameter += ( (((1 - bright) * (maxD - minD) + minD) * sizeMult) - diameter ) * .2;

// Influence by movement of general brightness
xv += brightVelX[(int)floor(x / (width/8.0))][(int)floor(y / (height/6.0))] * 1;
yv += brightVelY[(int)floor(x / (width/8.0))][(int)floor(y / (height/6.0))] * 1;
    }

    // Check for new connections
    for(int i=0; i < nStars; i++) {
if(i != id) {// && touching < 1 && stars[i].touching < 1) {  // If it's not me
  float xd = stars[i].x - x;
  float yd = stars[i].y - y;
  float diff = xd*xd + yd*yd;
  float radii = stars[i].diameter/2 + diameter/2;

  // If touching
  if(diff < radii*radii) {
    springAdd(stars[i].x, stars[i].y, radii);

    // Assimilate Velocity
    xv += (stars[i].xv - xv) * .01;
    yv += (stars[i].yv - yv) * .01;

    // Color changes with distance
    float dist = sqrt(diff);

    if(dist < 30) {
stroke(255, ((30 - dist) * 6) * (min(inside, stars[i].inside) / 60));
line(x, y, stars[i].x, stars[i].y);
    }

    if(!connected[i]) {
inside += diameter / (maxD / 5);
connected[i] = true;
    }
  } else {
    connected[i] = false;
  }
}
     }

     inside = constrain(inside, 0, 60);
   }

   void display()
   {
     ellipseMode(CENTER_DIAMETER);
     if(keyPressed && key == '`') {
ellipse(x, y, diameter, diameter);
     }
     if(inside > 1) {
imageMode(CENTER_DIAMETER);
tint(255, (inside-4)*64);

pushMatrix();
translate(0,0,-1);
image(basicStar, x, y, inside, inside);
popMatrix();
     }
     //line(x, y, x+xv, y+yv);

     x += xv;
     y += yv;

     // Constrain to screen
     float d2 = diameter/2;
     if(x < d2) { x = d2; }
     if(x > width - d2) { x = width - d2; }
     if(y < d2) { y = d2; }
     if(y > height - d2) { y = height - d2; }

     xv *= .8;
     yv *= .8;

     age++;
   }

   float dx, dy, mag, ext;
   void springAdd(float sx, float sy, float rest)
   {
     dx = sx - x;
     dy = sy - y;
     if(dx != 0 || dy != 0) {  // Prevent / by zero
mag = sqrt(dx*dx + dy*dy);
ext = mag - rest;
xv += (dx / mag * ext) * .1;
yv += (dy / mag * ext) * .1;
     }
   }
 }

 void brightToAlpha(PImage b)
 {
   b.format = ARGB;
   for(int i=0; i < b.pixels.length; i++) {
     b.pixels[i] = color(255,255,255,brightness(b.pixels[i]));
   }
 }