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Here you can Sed posuere consectetur est at lobortis. Donec ullamcorper nulla non metus auctor fringilla. Maecenas sed diam eget risus varius blandit sit amet non magna. Donec id elit non mi porta gravida at eget metus. Praesent commodo cursus magna, vel scelerisque nisl consectetur et.

            
              <div><canvas id="stage" width="600" height="500" ></canvas></div>


            
          
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              #stage, body{
  background-color:#fff;
  max-width:100%;
}

div{
  text-align:center;
  background:#fff;

}
#stage{
    border:1px solid silver;
    margin:0 auto;
}

            
          
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              var c = document.getElementById("stage");
var ctx = c.getContext("2d");

var centerX = c.width / 2;
var centerY = c.height / 2;
var radius = 10;
var numCircles = 8;
var numParticles = 256;

var pct = 0.0;
var animLength = 7;
var lineLength = 16;

var stop = false;
var frameCount = 0;
//var $results=$("#results");
var fps, fpsInterval, startTime, now, then, elapsed;

// initialize the timer variables and start the animation
startAnimating(60);

function startAnimating(fps) {
    fpsInterval = 1000 / fps;
    then = Date.now();
    startTime = then;
    animate();
}

function Orb() {
  this.r = 0;  
  this.p = {};
    this.v = {};
    this.a = {
        x: 0,
        y: 0
    };
    this.tail = [];
    this.ageo = 0;
  this.id = -1;
}

Orb.prototype.init = function(_x, _y) {
    this.p.x = _x;
    this.p.y = _y;

    var f = Math.random() * 4;

    var angle = Math.random() * Math.PI * 2;

    //this.v.x = Math.cos(angle) * f;
    //this.v.y = Math.sin(angle) * f;
  this.v.x = this.v.y = 0;
    this.age = 0;
}
Orb.prototype.update = function() {

    this.age++;

    this.v.x += this.a.x;
    this.v.y += this.a.y;

    var maxSpeed = 3.0;
    var direction = Math.atan2(this.v.y, this.v.x);

    var fwdSpeed = Math.sqrt(this.v.x * this.v.x + this.v.y * this.v.y);
    if (fwdSpeed > maxSpeed || fwdSpeed < -1 * maxSpeed) {
        var modifier = fwdSpeed / maxSpeed;
        this.v.x /= modifier;
        this.v.y /= modifier;

    }

    this.p.x += this.v.x;
    this.p.y += this.v.y;
    // floor
    if (this.p.y > c.height) {
        this.p.y -= this.v.y;
        this.v.y *= -Math.random();
        this.v.x *= Math.random() / 2 + 0.5;
    }
   // ceiling
    if (this.p.y < 0) {
        this.p.y -= this.v.y;
        this.v.y *= -Math.random();
        this.v.x *= Math.random() / 2 + 0.5;
    }
      // right wall
    if (this.p.x > c.width) {
        this.p.x -= this.v.x;
        this.v.x *= -Math.random();
        this.v.y *= Math.random() / 2 + 0.5;
    }
   // left wall
    if (this.p.x < 0) {
        this.p.x -= this.v.x;
        this.v.x *= -Math.random();
        this.v.y *= Math.random() / 2 + 0.5;
    }

    this.v.x *= 0.99;
    this.v.y *= 0.99;
  
  this.r = Math.atan2(this.v.y,this.v.x);
  
}
Orb.prototype.draw = function() {
    ctx.beginPath();
    ctx.arc(this.p.x, this.p.y, 2, 0, 2 * Math.PI, false);
  var c = 0;
  var c2 = 0;  
  //var c = Math.min(255-this.age * 8, 255);
    //var c2 = Math.min(255-this.age * 16, 255);
  //  ctx.fillStyle = "rgba(" + c + "," + c + "," + c + ",0.5)";
  //ctx.fillStyle = "rgba(0,0,0,1.0)";  
  ctx.fill();
    ctx.beginPath();
    ctx.moveTo(this.p.x, this.p.y);
  ctx.lineTo(this.p.x+Math.cos(this.r)*5,this.p.y+Math.sin(this.r)*5);
    for (var j = 1; j < this.tail.length; j++) {

        ctx.lineTo(this.tail[j].x, this.tail[j].y);

    }
    ctx.lineWidth = 1;
    ctx.strokeStyle = "rgba(" + c2 + "," + c2 + "," + c2 + ",1.0)";
    ctx.stroke();
    this.tail.unshift({
        x: this.p.x,
        y: this.p.y
    });
    if (this.tail.length > lineLength) this.tail.pop();

}
function steer(){
  var steerCount = 0;
  var steerVec = {
    x:0,
                      y:0
  };
  for(var i=0;i<numParticles;i++){
    for(var j=0;j<i;j++){
      var theDist = lineDistance(orbs[i].p,orbs[j].p);
      if(theDist<15){

      steerCount++;
      steerVec.x += orbs[j].v.x;
      steerVec.y += orbs[j].v.y;
                                                              
                                                              
       
        


        
        
        
      }
          if(steerCount>0){
        orbs[i].v.x += steerVec.x/steerCount*0.0008;
        orbs[i].v.y += steerVec.y/steerCount*0.0008;
        }
    }
  }
}
function avoid(){
  
  for(var i=0;i<numParticles;i++){
    for(var j=0;j<i;j++){
      var theDist = lineDistance(orbs[i].p,orbs[j].p);
      if(theDist<10){
      var theAngle = Math.atan2(orbs[j].p.y-orbs[i].p.y,orbs[j].p.x-orbs[i].p.x);
        var xa = Math.cos(theAngle);
        var ya = Math.sin(theAngle);
        
        orbs[i].v.x -= xa*5/(theDist*theDist);
        orbs[i].v.y -= ya*5/(theDist*theDist);
        orbs[j].v.x += xa*5/(theDist*theDist);
        orbs[j].v.y += ya*5/(theDist*theDist);
        
        
        
      }
    }
  }
  
}

function cohesion(){
  for(var i=0;i<numParticles;i++){
    for(var j=0;j<i;j++){
      var theDist = lineDistance(orbs[i].p,orbs[j].p);
      if(theDist<50){
      var theAngle = Math.atan2(orbs[j].p.y-orbs[i].p.y,orbs[j].p.x-orbs[i].p.x);
        var xa = Math.cos(theAngle);
        var ya = Math.sin(theAngle);
        
        orbs[i].v.x += xa*40/(theDist*theDist);
        orbs[i].v.y += ya*40/(theDist*theDist);
        orbs[j].v.x -= xa*40/(theDist*theDist);
        orbs[j].v.y -= ya*40/(theDist*theDist);
        
        
        
      }
    }
  }
}

function getMousePos(canvas, evt) {
    var rect = canvas.getBoundingClientRect();
    return {
        x: evt.clientX - rect.left,
        y: evt.clientY - rect.top
    };
}

var orbs;

function init(_x, _y) {
    orbs = [];
    for (var i = 0; i < numParticles; i++) {
        var o = new Orb();
        o.init(_x+Math.random()*10, _y+Math.random()*10);
      o.id = i;
        orbs.push(o);
    }
}
init(c.width / 2, c.height / 2);

c.addEventListener('mousedown', function(evt) {
    var mousePos = getMousePos(c, evt);

    init(mousePos.x, mousePos.y);
});

function animate() {

    // stop
    if (stop) {
        return;
    }

    // request another frame

    requestAnimationFrame(animate);

    // calc elapsed time since last loop

    now = Date.now();
    elapsed = now - then;

    // if enough time has elapsed, draw the next frame

    if (elapsed > fpsInterval) {

        // Get ready for next frame by setting then=now, but...
        // Also, adjust for fpsInterval not being multiple of 16.67
        then = now - (elapsed % fpsInterval);
        frameCount++;
        // draw stuff here
        drawStuff();

    }
}

function drawStuff() {

    ctx.clearRect(0, 0, c.width, c.height);

  avoid();
  steer();
  
    for (var i = 0; i < numParticles; i++) {
        var o = orbs[i];



       // o.a.x += Math.cos(Math.atan2(a.p.y - o.p.y, a.p.x - o.p.x)) * accel;
        //o.a.y += Math.sin(Math.atan2(a.p.y - o.p.y, a.p.x - o.p.x)) * accel;

        o.update();
    }

    for (var i = 0; i < numParticles; i++) {
        var o = orbs[i];
        o.draw();

    }

}


function lineDistance( point1, point2 )
{
  var xs = 0;
  var ys = 0;
 
  xs = point2.x - point1.x;
  xs = xs * xs;
 
  ys = point2.y - point1.y;
  ys = ys * ys;
 
  return Math.sqrt( xs + ys );
}
            
          
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