Skip to content

Instantly share code, notes, and snippets.

@bholzer bholzer/spider.js
Created Dec 10, 2014

Embed
What would you like to do?
$( function() {
var width, height, canvas, ctx, points, target, animateHeader = true;
// Main
initHeader();
initAnimation();
addListeners();
function initHeader() {
width = window.innerWidth;
height = window.innerHeight;
target = {
x: width / 2,
y: height / 3
};
canvas = document.getElementById( 'spiders' );
canvas.width = width;
canvas.height = height;
ctx = canvas.getContext( '2d' );
// create points
points = [];
for ( var x = 0; x < width; x = x + width / 20 ) {
for ( var y = 0; y < height; y = y + height / 20 ) {
var px = x + Math.random() * width / 20;
var py = y + Math.random() * height / 20;
var p = {
x: px,
originX: px,
y: py,
originY: py
};
points.push( p );
}
}
// for each point find the 5 closest points
for ( var i = 0; i < points.length; i++ ) {
var closest = [];
var p1 = points[ i ];
for ( var j = 0; j < points.length; j++ ) {
var p2 = points[ j ]
if ( !( p1 == p2 ) ) {
var placed = false;
for ( var k = 0; k < 5; k++ ) {
if ( !placed ) {
if ( closest[ k ] == undefined ) {
closest[ k ] = p2;
placed = true;
}
}
}
for ( var k = 0; k < 5; k++ ) {
if ( !placed ) {
if ( getDistance( p1, p2 ) < getDistance( p1, closest[ k ] ) ) {
closest[ k ] = p2;
placed = true;
}
}
}
}
}
p1.closest = closest;
}
// assign a circle to each point
for ( var i in points ) {
var c = new Circle( points[ i ], 2 + Math.random() * 2, 'rgba(255,255,255,0.3)' );
points[ i ].circle = c;
}
}
// Event handling
function addListeners() {
if ( !( 'ontouchstart' in window ) ) {
window.addEventListener( 'mousemove', mouseMove );
}
window.addEventListener( 'scroll', scrollCheck );
window.addEventListener( 'resize', resize );
}
function mouseMove( e ) {
var posx = posy = 0;
if ( e.pageX || e.pageY ) {
posx = e.pageX;
posy = e.pageY;
} else if ( e.clientX || e.clientY ) {
posx = e.clientX + document.body.scrollLeft + document.documentElement.scrollLeft;
posy = e.clientY + document.body.scrollTop + document.documentElement.scrollTop;
}
target.x = posx;
target.y = posy;
}
function scrollCheck() {
if ( document.body.scrollTop > height ) animateHeader = false;
else animateHeader = true;
}
function resize() {
width = window.innerWidth;
height = window.innerHeight;
canvas.width = width;
canvas.height = height;
}
// animation
function initAnimation() {
animate();
for ( var i in points ) {
shiftPoint( points[ i ] );
}
}
function animate() {
if ( animateHeader ) {
ctx.clearRect( 0, 0, width, height );
for ( var i in points ) {
// detect points in range
if ( Math.abs( getDistance( target, points[ i ] ) ) < 4000 ) {
points[ i ].active = 0.3;
points[ i ].circle.active = 0.6;
} else if ( Math.abs( getDistance( target, points[ i ] ) ) < 20000 ) {
points[ i ].active = 0.1;
points[ i ].circle.active = 0.3;
} else if ( Math.abs( getDistance( target, points[ i ] ) ) < 40000 ) {
points[ i ].active = 0.02;
points[ i ].circle.active = 0.1;
} else {
points[ i ].active = 0;
points[ i ].circle.active = 0;
}
drawLines( points[ i ] );
points[ i ].circle.draw();
}
}
requestAnimationFrame( animate );
}
function shiftPoint( p ) {
TweenLite.to( p, 1 + 1 * Math.random(), {
x: p.originX - 50 + Math.random() * 100,
y: p.originY - 50 + Math.random() * 100,
onComplete: function() {
shiftPoint( p );
}
} );
}
// Canvas manipulation
function drawLines( p ) {
if ( !p.active ) return;
for ( var i in p.closest ) {
ctx.beginPath();
ctx.moveTo( p.x, p.y );
ctx.lineTo( p.closest[ i ].x, p.closest[ i ].y );
ctx.strokeStyle = 'rgba(255,255,255,' + p.active + ')';
ctx.stroke();
}
}
function Circle( pos, rad, color ) {
var _this = this;
// constructor
( function() {
_this.pos = pos || null;
_this.radius = rad || null;
_this.color = color || null;
} )();
this.draw = function() {
if ( !_this.active ) return;
ctx.beginPath();
ctx.arc( _this.pos.x, _this.pos.y, _this.radius, 0, 2 * Math.PI, false );
ctx.fillStyle = 'rgba(255,255,255,' + _this.active + ')';
ctx.fill();
};
}
// Util
function getDistance( p1, p2 ) {
return Math.pow( p1.x - p2.x, 2 ) + Math.pow( p1.y - p2.y, 2 );
}
} );
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.