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Pen ID
Unlock Campus Themeforest adv

 

Code
CSS
body, html {
  margin: 0;
  padding: 0;
}

canvas {
  -webkit-touch-callout: none;
  -webkit-user-select: none;
  user-select: none;
}
canvas div {
  background-color: transparent;
}

#scene {
  background-color: black;
  -webkit-touch-callout: none;
  -webkit-user-select: none;
  user-select: none;
}
JS
//******************************************************
// Yet Another Particle Engine
var cos = Math.cos,
    sin = Math.sin,
    sqrt = Math.sqrt,
    abs = Math.abs,
    atan2 = Math.atan2,
    log = Math.log,
    random = Math.random,
    PI = Math.PI,
    sqr = function(v){return v*v;},
    particles = [],
    drawScale = 1,
    emitters = [],
    forces  = [],
    collidedMass = 0,
    maxParticles = 100,
    emissionRate = 1;

//-------------------------------------------------------
// Vectors, and not the kind you put stuff in
function Vector(x, y, z) {
  this.x = x || 0;
  this.y = y || 0;
  this.z = z || 0;
}
Vector.prototype = {
  add : function(vector) {
    this.x += vector.x;
    this.y += vector.y;
    this.z += vector.z;
    return this;
  },
  subtract : function(vector) {
    this.x -= vector.x;
    this.y -= vector.y;
    this.z -= vector.z;
    return this;
  },
  multiply : function(another) {
    this.x /= another.x;
    this.y /= another.y;
    this.z /= another.z;
    return this;
  },
  divide : function(another) {
    this.x /= another.x;
    this.y /= another.y;
    this.z /= another.z;
    return this;
  },
  scale : function(factor) {
    this.x *= factor;
    this.y *= factor;  
    this.z *= factor;  
    return this;      
  },
  magnitude : function () {
    return sqrt(sqr(this.x + this.y));
  },
  distance : function (another) {
    return abs(sqrt(sqr(this.x - another.x) + sqr(this.y - another.y)));
  },
  angle : function (angle, magnitude) {
    if(angle && magnitude)
      return Vector.fromAngle(angle, magnitude);
    return atan2(this.y, this.x);
  },
  clone : function() {
    return new Vector(this.x, this.y, this.z);
  },
  equals : function(another) {
    return this.x === another.x 
        && this.y === another.y
        && this.z === another.z;
  },
  random : function(r) {
    this.x += (random() * r * 2) - r;
    this.y += (random() * r * 2) - r;
    return this;
  }
};
Vector.fromAngle = function (angle, magnitude) {
  return new Vector(
    magnitude * cos(angle), 
    magnitude * sin(angle),
    magnitude * sin(angle));
};

//******************************************************
// A thing with mass, position, and velocity - like your mom
function Particle(pt, vc, ac, mass) {
  this.pos = pt || new Vector(0, 0);
  this.vc = vc || new Vector(0, 0);
  this.ac = ac || new Vector(0, 0);
  this.mass = mass || 1;
  this.alive = true;
}
Particle.prototype.move = function () {
  this.vc.add(this.ac);
  this.pos.add(this.vc);
};
Particle.prototype.reactToForces = function (fields) {
  var totalAccelerationX = 0;
  var totalAccelerationY = 0;
  
  for (var i = 0; i < fields.length; i++) {
    var field = fields[i];
    var vectorX = field.pos.x - this.pos.x;
    var vectorY = field.pos.y - this.pos.y;
    var distance = this.pos.distance(field.pos);
    if(distance < 1) field.grow(this);
    if(distance < 100) this.doubleSize = true;
    var force = G(this.forceBetween(field, distance));
    totalAccelerationX += vectorX * force;
    totalAccelerationY += vectorY * force;
  }
  this.ac = new Vector(totalAccelerationX, totalAccelerationY);
  
  totalAccelerationX = 0;
  totalAccelerationY = 0;
  for (var i = 0; i < particles.length; i++) {
    var field = particles[i];
    if(field === this || !field.alive) continue;
    var vectorX = field.pos.x - this.pos.x;
    var vectorY = field.pos.y - this.pos.y;
    var distance = this.pos.distance(field.pos);
    if(distance < 1) {
      if(this.mass >= field.mass) {
        var massRatio = this.mass / field.mass;
        if(particles.length <= maxParticles && this.mass>40) {
          this.alive = false;
          this.nova = true;
          collidedMass += this.mass;
        } else this.grow(field);
      } else this.alive = false;
    }
    if(this.alive) {
      var force = G(this.forceBetween(field, distance));
      totalAccelerationX += vectorX * G(force);
      totalAccelerationY += vectorY * G(force);
    }
  }

  var travelDist = this.pos.distance(this.lastPos ? this.lastPos : this.pos);
  this.velocity = travelDist - (this.lastDistance ? this.lastDistance : travelDist);
  this.lastDistance = travelDist;
  this.lastPos = this.pos.clone();

  this.ac.add(new Vector(totalAccelerationX, totalAccelerationY));
  this.lastPos = this.pos.clone();
  // if(this.mass > 20) {
  //   var chance = 1 / (this.mass - 20);
  //   if(Math.random()>chance) {
  //     this.supernova = true;
  //     this.supernovaDur = 10;
  //     this.alive = false;
  //     if(particles.length <= maxParticles) collidedMass += this.mass;
  //     delete this.size;
  //   }
  // }
};
Particle.prototype.grow = function (another) {
  this.mass += another.mass;
  this.nova = true;
  another.alive = false;
  delete this.size;
};
Particle.prototype.breakApart = function(minMass, maxParts) {
  if(!minMass) minMass = 1;
  if(!maxParts) maxParts = 2;
  var remainingMass = this.mass;
  var num = 0;
  while(remainingMass > 0) {
    var np = new Particle(this.pos.clone().random(this.mass), new Vector(0,0));
    np.mass = 1 + Math.random() * (remainingMass - 1);
    if(num>=maxParts-1) np.mass = remainingMass;
    np.mass = np.mass < minMass ? minMass : np.mass;
    remainingMass -= np.mass;
    num++;
  }
  this.nova = true;
  delete this.size;
  this.alive = false;
};
Particle.prototype.forceBetween = function(another, distance) {
  var distance = distance? distance : this.pos.distance(another.pos);
  return (this.mass * another.mass) / sqr(distance);
};

//******************************************************
//This certainly doesn't *sub*mit to particles, that's for sure
function ParticleEmitter(pos, vc, ang) {
  // to do config options for emitter - random, static, show emitter, emitter color, etc
  this.pos = pos; 
  this.vc = vc; 
  this.ang = ang || 0.09; 
  this.color = "#999"; 
}
ParticleEmitter.prototype.emit = function() {
  var angle = this.vc.angle() + 
      this.ang - (Math.random() * this.ang * 2);
  var magnitude = this.vc.magnitude();
  var position = this.pos.clone();
        position.add(
        new Vector(
          ~~((Math.random() * 100) - 50) * drawScale,       
          ~~((Math.random() * 100) - 50) * drawScale
        ));
  var velocity = Vector.fromAngle(angle, magnitude);
  return new Particle(position,velocity);
};

//******************************************************
// Use it, Luke
// to do collapse functionality into particle
function Force(pos, m) {
  this.pos = pos;
  this.mass = m || 100;
}
Force.prototype.grow = function (another) {
  this.mass += another.mass;
  this.burp = true;
  another.alive = false;
};



function G(data) {
  return 0.00674 * data;
}

//******************************************************
var canvas = document.querySelector('#scene');
var ctx = canvas.getContext('2d');
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
var canvasWidth = canvas.width;
var canvasHeight = canvas.height;

var renderToCanvas = function (width, height, renderFunction) {
    var buffer = document.createElement('canvas');
    buffer.width = width;
    buffer.height = height;
    renderFunction(buffer.getContext('2d'));
    return buffer;
};

maxParticles = 500; 
emissionRate = 1; 
drawScale = 1.3;
minParticleSize = 2;
emitters = [
  //br
  new ParticleEmitter(
    new Vector(
      canvasWidth / 2 * drawScale + 400, 
      canvasHeight / 2 * drawScale
      ), 
    Vector.fromAngle(2, 5),
    1
  ),
  //   // bl
  //   new ParticleEmitter(
  //   new Vector(
  //     canvasWidth / 2 * drawScale - 400, 
  //     canvasHeight / 2 * drawScale + 400
  //     ), 
  //   Vector.fromAngle(1.5, 1),
  //   1
  // ),
    // tl
  new ParticleEmitter(
    new Vector(
      canvasWidth / 2 * drawScale - 400, 
      canvasHeight / 2 * drawScale
      ), 
    Vector.fromAngle(5, 5),
    1
  ),
  //   // tr
  //   new ParticleEmitter(
  //   new Vector(
  //     canvasWidth / 2 * drawScale + 400, 
  //     canvasHeight / 2 * drawScale - 400
  //     ), 
  //   Vector.fromAngle(4.5, 1),
  //   1
  // )
];
forces  = [
  new Force(
    new Vector((canvasWidth / 2 * drawScale) ,
               (canvasHeight / 2 * drawScale)), 1800)
];

function loop() {
  clear();
  update();
  draw();
  queue();
}
 
function clear() {
  ctx.clearRect(0, 0, canvas.width, canvas.height);
}
    
var ctr = 0;
var c = [
  'rgba(255,255,255,',
  'rgba(0,150,255,',
  'rgba(255,255,128,',
  'rgba(255,255,255,'
];
function rndc() {
  return c[~~(Math.random() * c.length-1)];
}
var c2 = 'rgba(255,64,32,';
function addNewParticles() {
  var _emit = function() {
    var ret = 0;
    for (var i = 0; i < emitters.length; i++) {
      for (var j = 0; j < emissionRate; j++) {
        var p = emitters[i].emit();
        p.color = ( ctr % 10 === 0 )
          ? ( Math.random() * 5 <= 1 ? c2 : rndc() ) 
          : rndc();
        p.mass = ~~(Math.random() * 5);
        particles.push(p);
        ret += p.mass;
        ctr++;
      }
    }
    return ret;
  };
  if(collidedMass !== 0) {
    while(collidedMass !== 0) {
      collidedMass -= _emit();
      collidedMass = collidedMass<0 ? 0 :collidedMass;
    }
  }
  if (particles.length > maxParticles) 
    return;
  _emit();
}

var CLIPOFFSCREEN = 1,
    BUFFEROFFSCREEN = 2,
    LOOPSCREEN = 3;

function isPositionAliveAndAdjust(particle,check) {
  return true;
  var pos = particle.pos;
  if(!check) check = BUFFEROFFSCREEN;
  if(check === CLIPOFFSCREEN) {
    return !(!particle.alive || 
             pos.x < 0 || 
             (pos.x / drawScale) > boundsX || 
             pos.y < 0 || 
             (pos.y / drawScale) > boundsY);
  } else if(check === BUFFEROFFSCREEN) {
    return !(!particle.alive || 
             pos.x < -boundsX * drawScale || 
             pos.x > 2 * boundsX * drawScale || 
             pos.y < -boundsY * drawScale || 
             pos.y > 2 * boundsY * drawScale);      
  } else if(check === LOOPSCREEN) {
    if (pos.x < 0) pos.x = boundsX * drawScale;
    if ((pos.x / drawScale) > boundsX) pos.x = 0;
    if (pos.y < 0) pos.y = boundsY * drawScale;
    if ((pos.y / drawScale) > boundsY) pos.y = 0;
    return true;
  }
}

function plotParticles(boundsX, boundsY) {
  var currentParticles = [];
  for (var i = 0; i < particles.length; i++) {
    var particle = particles[i];
    particle.reactToForces(forces);
    if(!isPositionAliveAndAdjust(particle))
      continue;
    particle.move();
    currentParticles.push(particle);
  }
}

var offscreenCache = {};
function renderParticle(p) {
    var position = p.pos;
    if(!p.size) p.size = Math.floor(p.mass / 100);

    
    if(!p.opacity) p.opacity = 0.05;
    if(p.velocity > 0) {
      if(p.opacity<=0.18)
        p.opacity += 0.04;
    }
      if(p.opacity>0.08)
        p.opacity -= 0.02;

    var actualSize = p.size / drawScale;
    actualSize = actualSize < minParticleSize ? minParticleSize : actualSize;
    if(p.mass>8) actualSize *= 2;
    if(p.nova) {
      actualSize *= 4;
      p.nova = false;
    }
    if(p.doubleSize) {
      p.doubleSize = false;
      actualSize *= 2;
    }
    // if(p.supernova) {
    //   actualSize *= 6;
    //   opacity = 0.15;
    //   p.supernovaDur = p.supernovaDur - 1;
    //   if(p.supernovaDur === 0)
    //     p.supernova = false;
    // }
    var cacheKey = actualSize + '_' + p.opacity + '_' + p.color;
    var cacheValue = offscreenCache[cacheKey];
    if(!cacheValue) {
      cacheValue = renderToCanvas(actualSize * 32, actualSize * 32, function(ofsContext) {
        var opacity = p.opacity;
        var fills = [
          {size:actualSize/2,  opacity:1},
          {size:actualSize,  opacity:opacity},
          {size:actualSize * 2, opacity:opacity / 2},
          {size:actualSize * 4, opacity:opacity / 3},
          {size:actualSize * 8, opacity:opacity / 5},
          {size:actualSize * 16, opacity:opacity / 16}
        ];
        ofsContext.beginPath();
        for(var f in fills) {
          f = fills[f];
          ofsContext.fillStyle = p.color + f.opacity + ')';
          ofsContext.arc(
            actualSize * 16, 
            actualSize * 16, 
            f.size , 0, Math.PI*2, true); 
          ofsContext.fill();
        }
        ofsContext.closePath();
      });
      offscreenCache[cacheKey] = cacheValue;    
    } 
      var posX = p.pos.x / drawScale;
    var posY = p.pos.y / drawScale;
    ctx.drawImage(cacheValue, posX, posY);
}

var fills = [
  {size:15,opacity:1  },
  {size:25,opacity:0.3},
  {size:50,opacity:0.1} ];

function renderScene(ofsContext) {
  for (var i = 0; i < forces.length; i++) {
    var p = forces[i];
    var position = p.pos;
    var opacity = 1;
    
    ofsContext.beginPath();
    for(var f in fills) {
      f = fills[f];
      var o = p.burp === true ? 1 : f.opacity;
      p.burp = false;
      // ofsContext.fillStyle = 'rgba(255,255,255,' + o + ')';
      // ofsContext.arc(position.x / drawScale, 
      //   position.y / drawScale, 
      //   f.size / drawScale, 0, Math.PI*2, true); 
      // ofsContext.fill();
    }
    ofsContext.closePath();
  }
  
  for (var i = 0; i < particles.length; i++) {
    var p = particles[i];
    renderParticle(p);
  }
}

function draw() { 
  renderScene(ctx);
}

function update() {
  addNewParticles();
  plotParticles(canvas.width, canvas.height);
}
 
function queue() {
  window.requestAnimationFrame(loop);
}

$('canvas').mousedown(function(e){

});

$('canvas').mouseup(function(e){

});

loop();
Host Instantly Drag and Drop Website Builder

 

Description

An endless stream of particles pop in and out of existence as they are irresistibly drawn to the black hole in the middle - and to each other. This pen is part of my current exploration of particle systems and gravity. I plan to recreate this design in three dimensions using three.js next - I aim to create my own mini-universe sim one day.
Term
Mon, 11/27/2017 - 21:52

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