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<canvas id="canvas"></canvas>
body {
padding: 0;
margin: 0;
overflow: hidden;
}
//Code by: Kushagra Agarwal
//https://cssdeck.com/item/602/html5-canvas-particles-web-matrix
// RequestAnimFrame: a browser API for getting smooth animations
window.requestAnimFrame = (function(){
return window.requestAnimationFrame ||
window.webkitRequestAnimationFrame ||
window.mozRequestAnimationFrame ||
window.oRequestAnimationFrame ||
window.msRequestAnimationFrame ||
function( callback ){
window.setTimeout(callback, 1000 / 60);
};
})();
// Initializing the canvas
// I am using native JS here, but you can use jQuery,
// Mootools or anything you want
var canvas = document.getElementById("canvas");
// Initialize the context of the canvas
var ctx = canvas.getContext("2d");
// Set the canvas width and height to occupy full window
var W = window.innerWidth, H = window.innerHeight;
canvas.width = W;
canvas.height = H;
// Some variables for later use
var particleCount = 100,
particles = [],
minDist = 70,
dist;
// Function to paint the canvas black
function paintCanvas() {
// Set the fill color to black
ctx.fillStyle = "rgba(0,0,0,1)";
// This will create a rectangle of white color from the
// top left (0,0) to the bottom right corner (W,H)
ctx.fillRect(0,0,W,H);
}
// Now the idea is to create some particles that will attract
// each other when they come close. We will set a minimum
// distance for it and also draw a line when they come
// close to each other.
// The attraction can be done by increasing their velocity as
// they reach closer to each other
// Let's make a function that will act as a class for
// our particles.
function Particle() {
// Position them randomly on the canvas
// Math.random() generates a random value between 0
// and 1 so we will need to multiply that with the
// canvas width and height.
this.x = Math.random() * W;
this.y = Math.random() * H;
// We would also need some velocity for the particles
// so that they can move freely across the space
this.vx = -1 + Math.random() * 2;
this.vy = -1 + Math.random() * 2;
// Now the radius of the particles. I want all of
// them to be equal in size so no Math.random() here..
this.radius = 4;
// This is the method that will draw the Particle on the
// canvas. It is using the basic fillStyle, then we start
// the path and after we use the `arc` function to
// draw our circle. The `arc` function accepts four
// parameters in which first two depicts the position
// of the center point of our arc as x and y coordinates.
// The third value is for radius, then start angle,
// end angle and finally a boolean value which decides
// whether the arc is to be drawn in counter clockwise or
// in a clockwise direction. False for clockwise.
this.draw = function() {
ctx.fillStyle = "white";
ctx.beginPath();
ctx.arc(this.x, this.y, this.radius, 0, Math.PI * 2, false);
// Fill the color to the arc that we just created
ctx.fill();
}
}
// Time to push the particles into an array
for(var i = 0; i < particleCount; i++) {
particles.push(new Particle());
}
// Function to draw everything on the canvas that we'll use when
// animating the whole scene.
function draw() {
// Call the paintCanvas function here so that our canvas
// will get re-painted in each next frame
paintCanvas();
// Call the function that will draw the balls using a loop
for (var i = 0; i < particles.length; i++) {
p = particles[i];
p.draw();
}
//Finally call the update function
update();
}
// Give every particle some life
function update() {
// In this function, we are first going to update every
// particle's position according to their velocities
for (var i = 0; i < particles.length; i++) {
p = particles[i];
// Change the velocities
p.x += p.vx;
p.y += p.vy
// We don't want to make the particles leave the
// area, so just change their position when they
// touch the walls of the window
if(p.x + p.radius > W)
p.x = p.radius;
else if(p.x - p.radius < 0) {
p.x = W - p.radius;
}
if(p.y + p.radius > H)
p.y = p.radius;
else if(p.y - p.radius < 0) {
p.y = H - p.radius;
}
// Now we need to make them attract each other
// so first, we'll check the distance between
// them and compare it to the minDist we have
// already set
// We will need another loop so that each
// particle can be compared to every other particle
// except itself
for(var j = i + 1; j < particles.length; j++) {
p2 = particles[j];
distance(p, p2);
}
}
}
// Distance calculator between two particles
function distance(p1, p2) {
var dist, colorIndex;
dx = p1.x - p2.x;
dy = p1.y - p2.y;
dist = Math.sqrt(dx*dx + dy*dy);
// Draw the line when distance is smaller
// then the minimum distance
if(dist <= minDist) {
// Draw the line
ctx.beginPath();
colorIndex = parseInt((100.0 * dist/minDist))+25;
ctx.strokeStyle = "hsla(2," + colorIndex + "%,50%,"+ (1.2-dist/minDist) +")";
ctx.moveTo(p.x, p.y);
ctx.lineTo(p2.x, p2.y);
ctx.stroke();
// Some acceleration for the partcles
// depending upon their distance
var ax = dx/2000,
ay = dy/2000;
// Apply the acceleration on the particles
p1.vx -= ax;
p1.vy -= ay;
p2.vx += ax;
p2.vy += ay;
}
}
// Start the main animation loop using requestAnimFrame
function animloop() {
draw();
requestAnimFrame(animloop);
}
animloop();
Also see: Tab Triggers