Интерактивное звездное небо

<script>
const LiquidButton = class LiquidButton {
constructor(svg) {
const options = svg.dataset;
this.id = this.constructor.id || (this.constructor.id = 1);
this.constructor.id++;
this.xmlns = 'http://www.w3.org/2000/svg';
this.tension = options.tension * 1 || 0.4;
this.width = options.width * 1 || 218;
this.height = options.height * 1 || 56;
this.margin = options.margin || 40;
this.hoverFactor = options.hoverFactor || -0.1;
this.gap = options.gap || 5;
this.debug = options.debug || false;
this.forceFactor = options.forceFactor || 0.2;
this.color1 = options.color1 || '#151617';
this.color2 = options.color2 || '#151617';
this.color3 = options.color3 || '#151617';
this.textColor = options.textColor || '#fff';
this.text = options.text || 'Button';
this.svg = svg;
this.layers = [{
points: [],
viscosity: 0.5,
mouseForce: 100,
forceLimit: 2,
},{
points: [],
viscosity: 0.8,
mouseForce: 150,
forceLimit: 3,
}];
for (let layerIndex = 0; layerIndex < this.layers.length; layerIndex++) {
const layer = this.layers[layerIndex];
layer.viscosity = options['layer-' + (layerIndex + 1) + 'Viscosity'] * 1 || layer.viscosity;
layer.mouseForce = options['layer-' + (layerIndex + 1) + 'MouseForce'] * 1 || layer.mouseForce;
layer.forceLimit = options['layer-' + (layerIndex + 1) + 'ForceLimit'] * 1 || layer.forceLimit;
layer.path = document.createElementNS(this.xmlns, 'path');
this.svg.appendChild(layer.path);
}
this.wrapperElement = options.wrapperElement || document.body;
if (!this.svg.parentElement) {
this.wrapperElement.append(this.svg);
}

this.svgText = document.createElementNS(this.xmlns, 'text');
this.svgText.setAttribute('x', '50%');
this.svgText.setAttribute('y', '50%');
this.svgText.setAttribute('dy', ~~(this.height / 8) + 'px');
this.svgText.setAttribute('font-size', ~~(this.height / 3));
this.svgText.style.fontFamily = 'sans-serif';
this.svgText.setAttribute('text-anchor', 'middle');
this.svgText.setAttribute('pointer-events', 'none');
this.svg.appendChild(this.svgText);

this.svgDefs = document.createElementNS(this.xmlns, 'defs')
this.svg.appendChild(this.svgDefs);

this.touches = [];
this.noise = options.noise || 0;
document.body.addEventListener('touchstart', this.touchHandler);
document.body.addEventListener('touchmove', this.touchHandler);
document.body.addEventListener('touchend', this.clearHandler);
document.body.addEventListener('touchcancel', this.clearHandler);
this.svg.addEventListener('mousemove', this.mouseHandler);
this.svg.addEventListener('mouseout', this.clearHandler);
this.initOrigins();
this.animate();
}

get mouseHandler() {
return (e) => {
this.touches = [{
x: e.offsetX,
y: e.offsetY,
force: 1,
}];
};
}

get touchHandler() {
return (e) => {
this.touches = [];
const rect = this.svg.getBoundingClientRect();
for (let touchIndex = 0; touchIndex < e.changedTouches.length; touchIndex++) {
const touch = e.changedTouches[touchIndex];
const x = touch.pageX - rect.left;
const y = touch.pageY - rect.top;
if (x > 0 && y > 0 && x < this.svgWidth && y < this.svgHeight) {
this.touches.push({x, y, force: touch.force || 1});
}
}
e.preventDefault();
};
}

get clearHandler() {
return (e) => {
this.touches = [];
};
}

get raf() {
return this.__raf || (this.__raf = (
window.requestAnimationFrame ||
window.webkitRequestAnimationFrame ||
window.mozRequestAnimationFrame ||
function(callback){ setTimeout(callback, 10)}
).bind(window));
}

distance(p1, p2) {
return Math.sqrt(Math.pow(p1.x - p2.x, 2) + Math.pow(p1.y - p2.y, 2));
}

update() {
for (let layerIndex = 0; layerIndex < this.layers.length; layerIndex++) {
const layer = this.layers[layerIndex];
const points = layer.points;
for (let pointIndex = 0; pointIndex < points.length; pointIndex++) {
const point = points[pointIndex];
const dx = point.ox - point.x + (Math.random() - 0.5) * this.noise;
const dy = point.oy - point.y + (Math.random() - 0.5) * this.noise;
const d = Math.sqrt(dx * dx + dy * dy);
const f = d * this.forceFactor;
point.vx += f * ((dx / d) || 0);
point.vy += f * ((dy / d) || 0);
for (let touchIndex = 0; touchIndex < this.touches.length; touchIndex++) {
const touch = this.touches[touchIndex];
let mouseForce = layer.mouseForce;
if (
touch.x > this.margin &&
touch.x < this.margin + this.width &&
touch.y > this.margin &&
touch.y < this.margin + this.height
) {
mouseForce *= -this.hoverFactor;
}
const mx = point.x - touch.x;
const my = point.y - touch.y;
const md = Math.sqrt(mx * mx + my * my);
const mf = Math.max(-layer.forceLimit, Math.min(layer.forceLimit, (mouseForce * touch.force) / md));
point.vx += mf * ((mx / md) || 0);
point.vy += mf * ((my / md) || 0);
}
point.vx *= layer.viscosity;
point.vy *= layer.viscosity;
point.x += point.vx;
point.y += point.vy;
}
for (let pointIndex = 0; pointIndex < points.length; pointIndex++) {
const prev = points[(pointIndex + points.length - 1) % points.length];
const point = points[pointIndex];
const next = points[(pointIndex + points.length + 1) % points.length];
const dPrev = this.distance(point, prev);
const dNext = this.distance(point, next);

const line = {
x: next.x - prev.x,
y: next.y - prev.y,
};
const dLine = Math.sqrt(line.x * line.x + line.y * line.y);

point.cPrev = {
x: point.x - (line.x / dLine) * dPrev * this.tension,
y: point.y - (line.y / dLine) * dPrev * this.tension,
};
point.cNext = {
x: point.x + (line.x / dLine) * dNext * this.tension,
y: point.y + (line.y / dLine) * dNext * this.tension,
};
}
}
}

animate() {
this.raf(() => {
this.update();
this.draw();
this.animate();
});
}

get svgWidth() {
return this.width + this.margin * 2;
}

get svgHeight() {
return this.height + this.margin * 2;
}

draw() {
for (let layerIndex = 0; layerIndex < this.layers.length; layerIndex++) {
const layer = this.layers[layerIndex];
if (layerIndex === 1) {
if (this.touches.length > 0) {
while (this.svgDefs.firstChild) {
this.svgDefs.removeChild(this.svgDefs.firstChild);
}
for (let touchIndex = 0; touchIndex < this.touches.length; touchIndex++) {
const touch = this.touches[touchIndex];
const gradient = document.createElementNS(this.xmlns, 'radialGradient');
gradient.id = 'liquid-gradient-' + this.id + '-' + touchIndex;
const start = document.createElementNS(this.xmlns, 'stop');
start.setAttribute('stop-color', this.color3);
start.setAttribute('offset', '0%');
const stop = document.createElementNS(this.xmlns, 'stop');
stop.setAttribute('stop-color', this.color2);
stop.setAttribute('offset', '100%');
gradient.appendChild(start);
gradient.appendChild(stop);
this.svgDefs.appendChild(gradient);
gradient.setAttribute('cx', touch.x / this.svgWidth);
gradient.setAttribute('cy', touch.y / this.svgHeight);
gradient.setAttribute('r', touch.force);
layer.path.style.fill = 'url(#' + gradient.id + ')';
}
} else {
layer.path.style.fill = this.color2;
}
} else {
layer.path.style.fill = this.color1;
}
const points = layer.points;
const commands = [];
commands.push('M', points[0].x, points[0].y);
for (let pointIndex = 1; pointIndex < points.length; pointIndex += 1) {
commands.push('C',
points[(pointIndex + 0) % points.length].cNext.x,
points[(pointIndex + 0) % points.length].cNext.y,
points[(pointIndex + 1) % points.length].cPrev.x,
points[(pointIndex + 1) % points.length].cPrev.y,
points[(pointIndex + 1) % points.length].x,
points[(pointIndex + 1) % points.length].y
);
}
commands.push('Z');
layer.path.setAttribute('d', commands.join(' '));
}
this.svgText.textContent = this.text;
this.svgText.style.fill = this.textColor;
}

createPoint(x, y) {
return {
x: x,
y: y,
ox: x,
oy: y,
vx: 0,
vy: 0,
};
}

initOrigins() {
this.svg.setAttribute('width', this.svgWidth);
this.svg.setAttribute('height', this.svgHeight);
for (let layerIndex = 0; layerIndex < this.layers.length; layerIndex++) {
const layer = this.layers[layerIndex];
const points = [];
for (let x = ~~(this.height / 2); x < this.width - ~~(this.height / 2); x += this.gap) {
points.push(this.createPoint(
x + this.margin,
this.margin
));
}
for (let alpha = ~~(this.height * 1.25); alpha >= 0; alpha -= this.gap) {
const angle = (Math.PI / ~~(this.height * 1.25)) * alpha;
points.push(this.createPoint(
Math.sin(angle) * this.height / 2 + this.margin + this.width - this.height / 2,
Math.cos(angle) * this.height / 2 + this.margin + this.height / 2
));
}
for (let x = this.width - ~~(this.height / 2) - 1; x >= ~~(this.height / 2); x -= this.gap) {
points.push(this.createPoint(
x + this.margin,
this.margin + this.height
));
}
for (let alpha = 0; alpha <= ~~(this.height * 1.25); alpha += this.gap) {
const angle = (Math.PI / ~~(this.height * 1.25)) * alpha;
points.push(this.createPoint(
(this.height - Math.sin(angle) * this.height / 2) + this.margin - this.height / 2,
Math.cos(angle) * this.height / 2 + this.margin + this.height / 2
));
}
layer.points = points;
}
}
}


const redraw = () => {
button.initOrigins();
};

const buttons = document.getElementsByClassName('btn0009_liquid');
for (let buttonIndex = 0; buttonIndex < buttons.length; buttonIndex++) {
const button = buttons[buttonIndex];
button.liquidButton = new LiquidButton(button);
}
</script>