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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 class="ui">
  <p class="zoom"><span class="zoom zoomin">+</span><span class="zoom zoomout">-</span></p>
  <p class="zoomlevel"><span class="percent">100</span> % - (<span class="width"></span>px)(<span class="height"></span>px)</p>
  <p>Dead: <span class="dead">0</span></p>
  <p>Alive: <span class="alive">0</span></p>
  <p>Drawn: <span class="drawn">0</span></p>
  <p><span class="fps">0</span> FPS</p>
  <a class="save" href="" download="capture.png">Save</a>
</div>
            
          
!
            
              * {
  border: none;
  margin: 0;
}
html,
body {
  width: 100%;
  height: 100%;
  overflow: hidden;
}
body {
  //background: radial-gradient(#555, #111);
}
canvas {
  background: white;
  background: radial-gradient(#FFF, #DDD);
  //background: radial-gradient(hsl(40, 80%, 60%), hsl(0, 50%, 40%));
  //filter: blur(1px) contrast(5);
  //transform: scale(0.1);
  transform-origin: 0 0;
  //border: solid .8em green;
  width: 100%;
  height: 100%;
}
.ui {
  display: none;
  position: fixed;
  z-index: 5;
  bottom: 0;
  left: 0;
  width: 120px;
  padding: 10px;
  background: rgba(255,255,255,0.7);
  
  p {
    //color: white;
    font-size: 11px;
    font-weight: 700;
    
    &.zoom {
      margin-bottom: 5px;
      
      span {
        margin-right: 5px;
        border: solid 1px #777;
        cursor: pointer;
        border-radius: 2px;
        
        &.zoomin {
          padding: 2px 5px;
        }
        &.zoomout {
          padding: 2px 8px;
        }
        &:hover {
          background: black;
          color: white;
        }
      }
    }
  }
  
  span.zoom {
    
    
  }
}

            
          
!
            
              /**
 * @author Alex Andrix <alex@alexandrix.com>
 * @since 2018-12-02
 */

var App = {};
App.setup = function() {
  var canvas = document.createElement('canvas');
  this.filename = "spipa";
  canvas.width = window.innerWidth;
  canvas.height = window.innerHeight;
  this.canvas = canvas;
  document.getElementsByTagName('body')[0].appendChild(canvas);
  this.ctx = this.canvas.getContext('2d');
  this.width = this.canvas.width;
  this.height = this.canvas.height;
  this.dataToImageRatio = 1;
  this.ctx.imageSmoothingEnabled = false;
  this.ctx.webkitImageSmoothingEnabled = false;
  this.ctx.msImageSmoothingEnabled = false;
  this.xC = this.width / 2;
  this.yC = this.height / 2;
  
  this.stepCount = 0;
  this.particles = [];
  this.lifespan = 1000;
  this.popPerBirth = 1;
  this.maxPop = 300;
  this.birthFreq = 2;

  // Build grid
  this.gridSize = 8;// Motion coords
  this.gridSteps = Math.floor(1000 / this.gridSize);
  this.grid = [];
  var i = 0;
  for (var xx = -500; xx < 500; xx += this.gridSize) {
    for (var yy = -500; yy < 500; yy += this.gridSize) {
      // Radial field, triangular function of r with max around r0
      var r = Math.sqrt(xx*xx+yy*yy),
          r0 = 100,
          field;
      
      if (r < r0) field = 255 / r0 * r;
      else if (r > r0) field = 255 - Math.min(255, (r - r0)/2);
      
      this.grid.push({
        x: xx,
        y: yy,
        busyAge: 0,
        spotIndex: i,
        isEdge: (xx == -500 ? 'left' : 
                 (xx == (-500 + this.gridSize * (this.gridSteps-1)) ? 'right' : 
                  (yy == -500 ? 'top' : 
                   (yy == (-500 + this.gridSize *(this.gridSteps-1)) ? 'bottom' : 
                    false
                   )
                  )
                 )
                ),
        field: field
      });
      i++;
    }
  }
  this.gridMaxIndex = i;
  
  // Counters for UI
  this.drawnInLastFrame = 0;
  this.deathCount = 0;
  
  this.initDraw();
};
App.evolve = function() {
  var time1 = performance.now();
  
  this.stepCount++;
  
  // Increment all grid ages
  this.grid.forEach(function(e) {
    if (e.busyAge > 0) e.busyAge++;
  });
  
  if (this.stepCount % this.birthFreq == 0 && (this.particles.length + this.popPerBirth) < this.maxPop) {
    this.birth();
  }
  App.move();
  App.draw();
  
  var time2 = performance.now();
  
  // Update UI
  document.getElementsByClassName('dead')[0].textContent = this.deathCount;
  document.getElementsByClassName('alive')[0].textContent = this.particles.length;
  document.getElementsByClassName('fps')[0].textContent = Math.floor(1000 / (time2 - time1));
  document.getElementsByClassName('drawn')[0].textContent = this.drawnInLastFrame;
  
};
App.birth = function() {
  var x, y;
  var gridSpotIndex = Math.floor(Math.random() * this.gridMaxIndex),
      gridSpot = this.grid[gridSpotIndex],
      x = gridSpot.x, y = gridSpot.y;
  
  var particle = {
    hue: 200,// + Math.floor(50*Math.random()),
    sat: 95,//30 + Math.floor(70*Math.random()),
    lum: 20 + Math.floor(40*Math.random()),
    x: x, y: y,
    xLast: x, yLast: y,
    xSpeed: 0, ySpeed: 0,
    age: 0,
    ageSinceStuck: 0,
    attractor: {
      oldIndex: gridSpotIndex,
      gridSpotIndex: gridSpotIndex,// Pop at random position on grid
    },
    name: 'seed-' + Math.ceil(10000000 * Math.random())
  };
  this.particles.push(particle);
};
App.kill = function(particleName) {
 var newArray = _.reject(this.particles, function(seed) {
    return (seed.name == particleName);
  });
  this.particles = _.cloneDeep(newArray);
};
App.move = function() {
  for (var i = 0; i < this.particles.length; i++) {
    // Get particle
    var p = this.particles[i];
    
    // Save last position
    p.xLast = p.x; p.yLast = p.y;
    
    // Attractor and corresponding grid spot
    var index = p.attractor.gridSpotIndex,
        gridSpot = this.grid[index];
    
    // Maybe move attractor and with certain constraints
    if (Math.random() < 0.5) {
      // Move attractor
      if (!gridSpot.isEdge) {
        // Change particle's attractor grid spot and local move function's grid spot
        var topIndex = index - 1,
            bottomIndex = index + 1,
            leftIndex = index - this.gridSteps,
            rightIndex = index + this.gridSteps,
            topSpot = this.grid[topIndex],
            bottomSpot = this.grid[bottomIndex],
            leftSpot = this.grid[leftIndex],
            rightSpot = this.grid[rightIndex];
        
        // Choose neighbour with highest field value (with some desobedience...)
        var chaos = 30;
        var maxFieldSpot = _.maxBy([topSpot, bottomSpot, leftSpot, rightSpot], function(e) {
          return e.field + chaos * Math.random()
        });
        
        var potentialNewGridSpot = maxFieldSpot;
        if (potentialNewGridSpot.busyAge == 0 || potentialNewGridSpot.busyAge > 15) {// Allow wall fading
        //if (potentialNewGridSpot.busyAge == 0) {// Spots busy forever
          // Ok it's free let's go there
          p.ageSinceStuck = 0;// Not stuck anymore yay
          p.attractor.oldIndex = index;
          p.attractor.gridSpotIndex = potentialNewGridSpot.spotIndex;
          gridSpot = potentialNewGridSpot;
          gridSpot.busyAge = 1;
        } else p.ageSinceStuck++;
        
      } else p.ageSinceStuck++;
      
      if (p.ageSinceStuck == 10) this.kill(p.name);
    }
    
    // Spring attractor to center with viscosity
    var k = 8, visc = 0.4;
    var dx = p.x - gridSpot.x,
        dy = p.y - gridSpot.y,
        dist = Math.sqrt(dx*dx + dy*dy);
    
    // Spring
    var xAcc = -k * dx,
        yAcc = -k * dy;
    
    p.xSpeed += xAcc; p.ySpeed += yAcc;
    
    // Calm the f*ck down
    p.xSpeed *= visc; p.ySpeed *= visc;
    
    // Store stuff in particle brain
    p.speed = Math.sqrt(p.xSpeed * p.xSpeed + p.ySpeed * p.ySpeed);
    p.dist = dist;
    
    // Update position
    p.x += 0.1 * p.xSpeed; p.y += 0.1 * p.ySpeed;
    
    // Get older
    p.age++;
    
    // Kill if too old
    if (p.age > this.lifespan) {
      this.kill(p.name);
      this.deathCount++;
    }
  }
};
App.initDraw = function() {
  this.ctx.beginPath();
  this.ctx.rect(0, 0, this.width, this.height);
  this.ctx.fillStyle = 'black';
  this.ctx.fill();
  this.ctx.closePath();
};
App.draw = function() {
  this.drawnInLastFrame = 0;
  if (!this.particles.length) return false;
  
  this.ctx.beginPath();
  this.ctx.rect(0, 0, this.width, this.height);
  this.ctx.fillStyle = 'rgba(0, 0, 0, 0.1)';
  //this.ctx.fillStyle = 'rgba(255, 255, 255, 0.1)';
  this.ctx.fill();
  this.ctx.closePath();
  
  for (var i = 0; i < this.particles.length; i++) {
    // Draw particle
    var p = this.particles[i];
    
    var h, s, l, a;
    
    h = p.hue + this.stepCount/30;
    s = p.sat;
    l = p.lum;
    a = 1;
    
    var last = this.dataXYtoCanvasXY(p.xLast, p.yLast),
        now = this.dataXYtoCanvasXY(p.x, p.y);
    var attracSpot = this.grid[p.attractor.gridSpotIndex],
        attracXY = this.dataXYtoCanvasXY(attracSpot.x, attracSpot.y);
    var oldAttracSpot = this.grid[p.attractor.oldIndex],
        oldAttracXY = this.dataXYtoCanvasXY(oldAttracSpot.x, oldAttracSpot.y);
    
    this.ctx.beginPath();
    
    this.ctx.strokeStyle = 'hsla(' + h + ', ' + s + '%, ' + l + '%, ' + a + ')';
    this.ctx.fillStyle = 'hsla(' + h + ', ' + s + '%, ' + l + '%, ' + a + ')';
    
    // Particle trail
    this.ctx.moveTo(last.x, last.y);
    this.ctx.lineTo(now.x, now.y);
    
    this.ctx.lineWidth = 1.5 * this.dataToImageRatio;
    this.ctx.stroke();
    this.ctx.closePath();
    
    // Attractor positions
    this.ctx.beginPath();
    this.ctx.lineWidth = 1.5 * this.dataToImageRatio;
    this.ctx.moveTo(oldAttracXY.x, oldAttracXY.y);
    this.ctx.lineTo(attracXY.x, attracXY.y);
    this.ctx.arc(attracXY.x, attracXY.y, 1.5 * this.dataToImageRatio, 0, 2 * Math.PI, false);
    
    //a /= 20;
    this.ctx.strokeStyle = 'hsla(' + h + ', ' + s + '%, ' + l + '%, ' + a + ')';
    this.ctx.fillStyle = 'hsla(' + h + ', ' + s + '%, ' + l + '%, ' + a + ')';
    this.ctx.stroke();
    this.ctx.fill();
    
    this.ctx.closePath();
    
    // UI counter
    this.drawnInLastFrame++;
  }
  
};
App.dataXYtoCanvasXY = function(x, y) {
  var zoom = 1.6;
  var xx = this.xC + x * zoom * this.dataToImageRatio,
      yy = this.yC + y * zoom * this.dataToImageRatio;
  
  return {x: xx, y: yy};
};

document.addEventListener('DOMContentLoaded', function() {
  App.setup();
  App.draw();
  
  var frame = function() {
    App.evolve();
    requestAnimationFrame(frame);
  };
  frame();
});

 
/**
 * Some old util I use at times
 *
 * @param {Number} Xstart X value of the segment starting point
 * @param {Number} Ystart Y value of the segment starting point
 * @param {Number} Xtarget X value of the segment target point
 * @param {Number} Ytarget Y value of the segment target point
 * @param {Boolean} realOrWeb true if Real (Y towards top), false if Web (Y towards bottom)
 * @returns {Number} Angle between 0 and 2PI
 */
segmentAngleRad = function(Xstart, Ystart, Xtarget, Ytarget, realOrWeb) {
	var result;// Will range between 0 and 2PI
	if (Xstart == Xtarget) {
		if (Ystart == Ytarget) {
			result = 0; 
		} else if (Ystart < Ytarget) {
			result = Math.PI/2;
		} else if (Ystart > Ytarget) {
			result = 3*Math.PI/2;
		} else {}
	} else if (Xstart < Xtarget) {
		result = Math.atan((Ytarget - Ystart)/(Xtarget - Xstart));
	} else if (Xstart > Xtarget) {
		result = Math.PI + Math.atan((Ytarget - Ystart)/(Xtarget - Xstart));
	}
	
	result = (result + 2*Math.PI)%(2*Math.PI);
	
	if (!realOrWeb) {
		result = 2*Math.PI - result;
	}
	
	return result;
}

            
          
!
999px
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