// Background circle effects
var canvas = document.getElementsByClassName('canvas')[0];
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
var canvas = document.getElementsByClassName('canvasbg')[0];
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
// min and max radius, radius threshold and percentage of filled circles
var radMin = 5,
radMax = 100,
filledCircle = 60, //percentage of filled circles
concentricCircle = 30, //percentage of concentric circles
radThreshold = 20; //IFF special, over this radius concentric, otherwise filled
//min and max speed to move
var speedMin = 0,
speedMax = 0.3;
//max reachable opacity for every circle and blur effect
var maxOpacity = 0.6;
//default palette choice
var colors = ['255,255,255', '220,220,220', '190,190,190', '160,160,160', '130,130,130', '100,100,100'],
bgColors = ['67, 160, 206', '67, 160, 206', '67, 160, 206', '67, 160, 206', '67, 160, 206', '67, 160, 206'],
circleBorder = 10,
backgroundLine = bgColors[0];
var backgroundMlt = 0.85;
//min distance for links
var linkDist = Math.min(canvas.width, canvas.height) / 3,
lineBorder = 2.5;
//most importantly: number of overall circles and arrays containing them
var maxCircles = 10,
points = [],
pointsBack = [];
//populating the screen
for (var i = 0; i < maxCircles * 2; i++) points.push(new Circle());
for (var i = 0; i < maxCircles; i++) pointsBack.push(new Circle(true));
//experimental vars
var circleExp = 1,
circleExpMax = 1.003,
circleExpMin = 0.997,
circleExpSp = 0.00004,
circlePulse = false;
//circle class
function Circle(background) {
//if background, it has different rules
this.background = (background || false);
this.x = randRange(-canvas.width / 2, canvas.width / 2);
this.y = randRange(-canvas.height / 2, canvas.height / 2);
this.radius = background ? hyperRange(radMin, radMax) * backgroundMlt : hyperRange(radMin, radMax);
this.filled = this.radius < radThreshold ? (randint(0, 100) > filledCircle ? false : 'full') : (randint(0, 100) > concentricCircle ? false : 'concentric');
this.color = background ? bgColors[randint(0, bgColors.length - 1)] : colors[randint(0, colors.length - 1)];
this.borderColor = background ? bgColors[randint(0, bgColors.length - 1)] : colors[randint(0, colors.length - 1)];
this.opacity = 0.05;
this.speed = (background ? randRange(speedMin, speedMax) / backgroundMlt : randRange(speedMin, speedMax)); // * (radMin / this.radius);
this.speedAngle = Math.random() * 2 * Math.PI;
this.speedx = Math.cos(this.speedAngle) * this.speed;
this.speedy = Math.sin(this.speedAngle) * this.speed;
var spacex = Math.abs((this.x - (this.speedx < 0 ? -1 : 1) * (canvas.width / 2 + this.radius)) / this.speedx),
spacey = Math.abs((this.y - (this.speedy < 0 ? -1 : 1) * (canvas.height / 2 + this.radius)) / this.speedy);
this.ttl = Math.min(spacex, spacey);
};
Circle.prototype.init = function() {
Circle.call(this, this.background);
}
//support functions
//generate random int a<=x<=b
function randint(a, b) {
return Math.floor(Math.random() * (b - a + 1) + a);
}
//generate random float
function randRange(a, b) {
return Math.random() * (b - a) + a;
}
//generate random float more likely to be close to a
function hyperRange(a, b) {
return Math.random() * Math.random() * Math.random() * (b - a) + a;
}
//rendering function
function drawCircle(ctx, circle) {
//circle.radius *= circleExp;
var radius = circle.background ? circle.radius *= circleExp : circle.radius /= circleExp;
ctx.beginPath();
ctx.arc(circle.x, circle.y, radius * circleExp, 0, 2 * Math.PI, false);
ctx.lineWidth = Math.max(1, circleBorder * (radMin - circle.radius) / (radMin - radMax));
ctx.strokeStyle = ['rgba(', circle.borderColor, ',', circle.opacity, ')'].join('');
if (circle.filled == 'full') {
ctx.fillStyle = ['rgba(', circle.borderColor, ',', circle.background ? circle.opacity * 0.8 : circle.opacity, ')'].join('');
ctx.fill();
ctx.lineWidth=0;
ctx.strokeStyle = ['rgba(', circle.borderColor, ',', 0, ')'].join('');
}
ctx.stroke();
if (circle.filled == 'concentric') {
ctx.beginPath();
ctx.arc(circle.x, circle.y, radius / 2, 0, 2 * Math.PI, false);
ctx.lineWidth = Math.max(1, circleBorder * (radMin - circle.radius) / (radMin - radMax));
ctx.strokeStyle = ['rgba(', circle.color, ',', circle.opacity, ')'].join('');
ctx.stroke();
}
circle.x += circle.speedx;
circle.y += circle.speedy;
if (circle.opacity < (circle.background ? maxOpacity : 1)) circle.opacity += 0.01;
circle.ttl--;
}
//initializing function
function init() {
window.requestAnimationFrame(draw);
}
//rendering function
function draw() {
if (circlePulse) {
if (circleExp < circleExpMin || circleExp > circleExpMax) circleExpSp *= -1;
circleExp += circleExpSp;
}
var ctxfr = document.getElementById('canvas').getContext('2d');
var ctxbg = document.getElementById('canvasbg').getContext('2d');
ctxfr.globalCompositeOperation = 'destination-over';
ctxfr.clearRect(0, 0, canvas.width, canvas.height); // clear canvas
ctxbg.globalCompositeOperation = 'destination-over';
ctxbg.clearRect(0, 0, canvas.width, canvas.height); // clear canvas
ctxfr.save();
ctxfr.translate(canvas.width / 2, canvas.height / 2);
ctxbg.save();
ctxbg.translate(canvas.width / 2, canvas.height / 2);
//function to render each single circle, its connections and to manage its out of boundaries replacement
function renderPoints(ctx, arr) {
for (var i = 0; i < arr.length; i++) {
var circle = arr[i];
//checking if out of boundaries
if (circle.ttl<0) {}
var xEscape = canvas.width / 2 + circle.radius,
yEscape = canvas.height / 2 + circle.radius;
if (circle.ttl < -20) arr[i].init(arr[i].background);
//if (Math.abs(circle.y) > yEscape || Math.abs(circle.x) > xEscape) arr[i].init(arr[i].background);
drawCircle(ctx, circle);
}
for (var i = 0; i < arr.length - 1; i++) {
for (var j = i + 1; j < arr.length; j++) {
var deltax = arr[i].x - arr[j].x;
var deltay = arr[i].y - arr[j].y;
var dist = Math.pow(Math.pow(deltax, 2) + Math.pow(deltay, 2), 0.5);
//if the circles are overlapping, no laser connecting them
if (dist <= arr[i].radius + arr[j].radius) continue;
//otherwise we connect them only if the dist is < linkDist
if (dist < linkDist) {
var xi = (arr[i].x < arr[j].x ? 1 : -1) * Math.abs(arr[i].radius * deltax / dist);
var yi = (arr[i].y < arr[j].y ? 1 : -1) * Math.abs(arr[i].radius * deltay / dist);
var xj = (arr[i].x < arr[j].x ? -1 : 1) * Math.abs(arr[j].radius * deltax / dist);
var yj = (arr[i].y < arr[j].y ? -1 : 1) * Math.abs(arr[j].radius * deltay / dist);
ctx.beginPath();
ctx.moveTo(arr[i].x + xi, arr[i].y + yi);
ctx.lineTo(arr[j].x + xj, arr[j].y + yj);
var samecolor = arr[i].color == arr[j].color;
ctx.strokeStyle = ["rgba(", arr[i].borderColor, ",", Math.min(arr[i].opacity, arr[j].opacity) * ((linkDist - dist) / linkDist), ")"].join("");
ctx.lineWidth = (arr[i].background ? lineBorder * backgroundMlt : lineBorder) * ((linkDist - dist) / linkDist); //*((linkDist-dist)/linkDist);
ctx.stroke();
}
}
}
}
var startTime = Date.now();
renderPoints(ctxfr, points);
renderPoints(ctxbg, pointsBack);
deltaT = Date.now() - startTime;
ctxfr.restore();
ctxbg.restore();
window.requestAnimationFrame(draw);
}
init();
/*Credits and aknowledgements:
Original Idea and Design by Luca Luzzatti
Optimizing tips from Benjamin Kästner
General tips from Salvatore Previti*/
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