JavaScript preprocessors can help make authoring JavaScript easier and more convenient. For instance, CoffeeScript can help prevent easy-to-make mistakes and offer a cleaner syntax and Babel can bring ECMAScript 6 features to browsers that only support ECMAScript 5.
Any URL's added here will be added as <script>
s in order, and run before the JavaScript in the editor. You can use the URL of any other Pen and it will include the JavaScript from that Pen.
You can apply a script from anywhere on the web to your Pen. Just put a URL to it here and we'll add it, in the order you have them, before the JavaScript in the Pen itself.
If the script you link to has the file extension of a preprocessor, we'll attempt to process it before applying.
You can also link to another Pen here, and we'll pull the JavaScript from that Pen and include it. If it's using a matching preprocessor, we'll combine the code before preprocessing, so you can use the linked Pen as a true dependency.
HTML Settings
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>
#stage, body{
background-color:#fff;
max-width:100%;
}
div{
text-align:center;
background:#fff;
}
#stage{
border:1px solid silver;
margin:0 auto;
}
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 );
}
Also see: Tab Triggers