var fishies = [];

​

function setup() {

  createCanvas(400, 400);

   for (var i = 0; i < 700 ; i++){

     fishies.push(new fish(random(width),random(height)));

  }

}

​

  function mousePressed(){

     attractors.push(createVector(mouseX, mouseY));

  }

​

function draw() {

  background(51);

  stroke(255);

  strokeWeight(8);

  for (var i = 0; i < attractors.length; i++){

    stroke(255,0,0);

    point(attractors[i].x, attractors[i].y);

     var r = floor(random(4));

    switch (r) {

     case 0:

       attractors[i].x = attractors[i].x + random(1,4);

       break;

     case 1:

       attractors[i].x = attractors[i].x - random(1,4);

       break;

       case 2:

       attractors[i].y = attractors[i].y + random(1,4);

       break;

     case 3:

       attractors[i].y = attractors[i].y - random(1,4);

       break;

   }

  }

  for (var i = 0; i < fishies.length; i++){

    var fish = fishies[i]

    for (var j = 0; j < attractors.length; j++){

      fish.attracted(attractors[j]);

    }

    fish.show();

    fish.update();

  }

}

​

function fish(x,y){

  this.pos = createVector(x,y);

  this.vel = p5.Vector.random2D();

  this.acc = createVector();

  this.update = function(){

    this.vel.add(this.acc);

    this.vel.limit(2);

    this.pos.add(this.vel);

    this.acc.mult(0);

  }

  this.show = function(){

    stroke(255);

    strokeWeight(3);

    point(this.pos.x, this.pos.y);

  }

  this.attracted = function(target){

    var force = p5.Vector.sub(target, this.pos);

    var d = force.mag();

    d = constrain(d, 2, 25);

    var G = 10;

    var strength = G / (d * d);

    force.setMag(strength);

    if (d < 20){

      force.mult(-5);

    }

    this.acc.add(force);

  }

}