Flow

ArrayList<Mover> movs;

ArrayList<PVector> forces;

int cols, rows, granularity;

float gridX, gridY, xoff, yoff, zoff;

PVector initforce;

​

void rotate2D(PVector v, float theta) {

  // What's the magnitude?

  float m = v.mag();

  // What's the angle?

  float a = v.heading2D();

  // Change the angle

  a += theta;

  // Polar to cartesian for the new xy components

  v.x = m * cos(a);

  v.y = m * sin(a);

}

​

void setup(){

  //size(400, 400);

  fullScreen();

  cols = 30;

  rows = 30;

  gridX = width/cols;

  gridY = height/rows;

  zoff = 0;

  yoff = 0;

  xoff = 0;

  granularity = 6;

  initforce= PVector.random2D();

  initforce.setMag(1);

  movs = new ArrayList<Mover>();

  forces = new ArrayList<PVector>();

  for(int i = 0; i < cols * rows; i++){

    xoff = map((i * gridX) % width, 0, width, 0, granularity);

    yoff = map(floor((i)/cols) * gridY, 0, width, 0, granularity);

    float angle = noise(xoff, yoff, zoff) * 2*PI;

    pushMatrix();

    translate((i * gridX) % width, floor((i)/cols) * gridY);

    PVector force = new PVector(initforce.x, initforce.y);

    rotate2D(force,angle);

    forces.add(force);

    popMatrix();

  }

}

​

void draw(){

  background(0);

  if(frameCount < 1000) {

    Mover m = new Mover(new PVector(random(20, width - 20), random(20, height - 20)));

    movs.add(m);

  }

  for(int i = 0; i < cols * rows; i++){

    PVector force =  forces.get(i);

    pushMatrix();

    translate((i * gridX) % width, floor((i)/cols) * gridY);

    stroke(255);

    line(0, 0, force.x * 20, force.y * 20);

    xoff = map((i * gridX) % width, 0, width, 0, granularity);

    yoff = map(floor((i)/cols) * gridY, 0, width, 0, granularity);

    float angle = noise(xoff, yoff, zoff) * 2*PI;

    PVector f = new PVector(initforce.x, initforce.y);

    rotate2D(f,angle);

    forces.set(i, f);

    popMatrix();

  }

  for(Mover m : movs){

    if (floor(m.pos.x/gridX) + floor(m.pos.y/gridY) * (cols)  < forces.size() ){   

        PVector f =  forces.get(floor(m.pos.x/gridX) + floor(m.pos.y/gridY) * (cols) );

        m.addForce(f);

    }

    m.update();

    m.show();

  }

  zoff += 0.01;

}