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lightning.html
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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Lightning Visualization</title>
<script src="https://cdnjs.cloudflare.com/ajax/libs/simplex-noise/2.4.0/simplex-noise.min.js"></script>
<style>
body {
font-family: Helvetica, sans-serif;
margin: 0;
overflow: hidden;
background-color: #222;
-webkit-user-select: none;
user-select: none;
}
canvas {
display: block;
position: absolute;
top: 0;
left: 0;
}
</style>
</head>
<body>
<canvas id="c"></canvas>
<script>
/**
* requestAnimationFrame
*/
window.requestAnimationFrame = (function(){
return window.requestAnimationFrame ||
window.webkitRequestAnimationFrame ||
window.mozRequestAnimationFrame ||
window.oRequestAnimationFrame ||
window.msRequestAnimationFrame ||
function (callback) { window.setTimeout(callback, 1000 / 60); };
})();
/**
* Lightning
*/
var Lightning = (function(window) {
/**
* LightningAbstract
*/
var LightningAbstract = {
points: null,
children: null,
_simplexNoise: new SimplexNoise(),
render: function(ctx, controls) {
this._update(controls);
this._draw(ctx);
},
_update: function(controls) {
throw new Error('Not override');
},
_draw: function(ctx) {
var points = this.points,
isRoot = false, opts,
p, p1, dx, dy, dist,
lineWidth,
i, len;
isRoot = !this.parent;
opts = isRoot ? this : this.parent;
if (isRoot) { // is root
var radius, gradient,
children = this.children, c;
ctx.save();
for (i = 0, len = points.length; i < len; i += len - 1) {
p = points[i];
radius = Math.random() * (8 - 3) + 3;
gradient = ctx.createRadialGradient(p.x, p.y, radius / 3, p.x, p.y, radius);
gradient.addColorStop(0, this._colorToString(1));
gradient.addColorStop(1, this._colorToString(0));
ctx.fillStyle = gradient;
ctx.beginPath();
ctx.arc(p.x, p.y, radius, 0, Math.PI * 2, false);
ctx.fill();
}
ctx.restore();
for (i = 0, len = children.length; i < len; i += len - 1) {
children[i].render(ctx);
}
}
ctx.save();
ctx.globalCompositeOperation = 'lighter';
ctx.lineCap = 'round';
ctx.fillStyle = 'rgba(0, 0, 0, 1)';
ctx.shadowBlur = opts.blur;
ctx.shadowColor = this._colorToString(1);
ctx.beginPath();
for (i = 0, len = points.length; i < len; i++) {
p = points[i];
if (len > 1) {
p1 = points[i === len - 1 ? i - 1 : i + 1];
dx = p.x - p1.x;
dy = p.y - p1.y;
dist = Math.sqrt(dx * dx + dy * dy);
} else {
dist = 0;
}
if (dist > 30) dist = 30;
ctx.moveTo(p.x + dist, p.y);
ctx.arc(p.x, p.y, dist, 0, Math.PI * 2, false);
}
ctx.fill();
ctx.restore();
ctx.save();
ctx.beginPath();
ctx.strokeStyle = this._colorToString(Math.random() * (opts.maxAlpha - opts.minAlpha) + opts.minAlpha);
lineWidth = Math.random() * (opts.maxLineWidth - opts.minLineWidth) + opts.minLineWidth;
ctx.lineWidth = isRoot ? lineWidth : lineWidth * 0.5;
for (i = 0; i < len; i++) {
p = points[i];
ctx[i === 0 ? 'moveTo' : 'lineTo'](p.x, p.y);
}
ctx.stroke();
ctx.restore();
},
_noise2d: function(x, y) {
var octaves = 3,
fallout = 0.5,
amp = 1, f = 1, sum = 0,
i;
for (i = 0; i < octaves; ++i) {
amp *= fallout;
sum += amp * (this._simplexNoise.noise2D(x * f, y * f) + 1) * 0.5;
f *= 2;
}
return sum;
},
_filterApply: function(points, lineLength, segmentsNum, base, amp, offset) {
var pointsOld = this.points,
// spline
spline = [],
catmullRom = this._catmullRom,
p0, p1, p2, p3, t, per,
// noise
p, next, angle, sin, cos, nx, av, ax, ay, bv, bx, by, m, px, py,
// shortest
shortest, dx, dy, distSq, minDist,
i, len, j, k;
// Spline
// スプライン補完用に配列の前後にラインの始点, 終点の参照をそれぞれ複製する
points.unshift(points[0]);
points.push(points[points.length - 1]);
per = 1 / segmentsNum;
// スプライン曲線のポイントを取得
for (i = 0, len = points.length - 3; i < len; i++) {
p0 = points[i];
p1 = points[i + 1];
p2 = points[i + 2];
p3 = points[i + 3];
for (j = 0; j < segmentsNum; j++) {
t = (j + 1) * per;
spline.push({
x: catmullRom(p0.x, p1.x, p2.x, p3.x, t),
y: catmullRom(p0.y, p1.y, p2.y, p3.y, t)
});
}
}
// 補完用に追加した参照を削除
points.pop();
// 削除のついでに描画の始点として追加
spline.unshift(points.shift());
// Noise
points = [];
len = spline.length;
per = 1 / (len - 1);
base = 1 / base;
for (i = 0, len = spline.length; i < len; i++) {
p = spline[i];
next = i === len - 1 ? p : spline[i + 1];
angle = Math.atan2(next.y - p.y, next.x - p.x);
sin = Math.sin(angle);
cos = Math.cos(angle);
nx = i * base;
av = lineLength * this._noise2d(nx - offset, offset) * 0.5 * amp;
ax = av * sin;
ay = av * cos;
bv = lineLength * this._noise2d(nx + offset, offset) * 0.5 * amp;
bx = bv * sin;
by = bv * cos;
m = Math.sin(Math.PI * (i * per));
px = p.x + (ax - bx) * m;
py = p.y - (ay - by) * m;
if (pointsOld.length) {
p = pointsOld.shift();
p.x = px;
p.y = py;
} else {
p = { x: px, y: py };
}
points.push(p);
}
// Shortest
shortest = [points[0]];
for (i = 0, len = points.length; i < len; i++) {
p = points[i];
minDist = Infinity;
k = -1;
for (j = i; j < len; j++) {
p2 = points[j];
dx = p.x - p2.x;
dy = p.y - p2.y;
distSq = dx * dx + dy * dy;
if (p !== p2 && distSq < minDist * minDist) {
minDist = Math.sqrt(distSq);
k = j;
}
}
if (k < 0) break;
shortest.push(points[k]);
i = k - 1;
}
return shortest;
},
_catmullRom: function(p0, p1, p2, p3, t) {
var v0 = (p2 - p0) * 0.5,
v1 = (p3 - p1) * 0.5;
return (2 * p1 - 2 * p2 + v0 + v1) * t * t * t +
(-3 * p1 + 3 * p2 - 2 * v0 - v1) * t * t + v0 * t + p1;
},
_colorToString: function(alpha) {
var c = this.color;
return this.colorType === 'rgb' ?
'rgba(' + c.join(',') + ',' + alpha + ')' :
'hsla(' + c[0] + ',' + c[1] + '%,' + c[2] + '%,' + alpha + ')';
}
};
/**
* @constructor
*/
function Lightning(segmentsNum) {
this.points = [];
this.children = [];
this._params = [];
this._offsets = [];
}
Lightning.prototype = extend(LightningAbstract, {
color: [255, 255, 255],
colorType: 'rgb',
blur: 50,
maxAlpha: 1,
minAlpha: 0.75,
maxLineWidth: 5,
minLineWidth: 0.5,
_params: null,
_offsets: null,
addParam: function(segmentsNum, base, amplitude, speed) {
this._params.push({
segmentsNum: segmentsNum,
base: base,
amplitude: amplitude,
speed: speed
});
this._offsets[this._params.length - 1] = 0;
},
createChild: function(base, amplitude, speed) {
var child = new LChild(this, {
base: base || this._params.base,
amplitude: amplitude || this._params.amplitude,
speed: speed || this._params.speed
});
this.children.push(child);
return child;
},
_update: function(points) {
var params = this._params, param,
offsets = this._offsets,
lineLength,
p0, p1, dx, dy,
i, ilen, j, jlen;
for (i = 0, ilen = params.length; i < ilen; i++) {
param = params[i];
lineLength = 0;
for (j = 0, jlen = points.length; j < jlen; j++) {
if (j !== jlen - 1) {
p0 = points[j];
p1 = points[j + 1];
dx = p0.x - p1.x;
dy = p0.y - p1.y;
lineLength += dx * dx + dy * dy;
}
}
lineLength = Math.sqrt(lineLength);
offsets[i] += Math.random() * param.speed;
points = this._filterApply(points, lineLength, param.segmentsNum, param.base, param.amplitude, offsets[i]);
}
this.points = points;
}
});
/**
* LChild
*/
function LChild(parent, param) {
this.parent = parent;
this.points = [];
this._param = param;
}
LChild.prototype = extend(LightningAbstract, {
parent: null,
_startStep: 0,
_endStep: 0,
_separate: 2,
_param: null,
_offset: 0,
_lastChangeTime: 0,
_update: function() {
var parent = this.parent,
plen = this.parent.points.length,
param = this._param,
points = [],
currentTime,
range, rangeLen, sep, seg,
c0, c1, dx, dy, lineLength,
i, j;
// 一定時間ごと, あるいは親のポイントの数が子の終了ステップ位置を下回った場合に始点と終点の親からの取得位置を更新する
currentTime = new Date().getTime();
if (
currentTime - this._lastChangeTime > 10000 * Math.random() ||
plen < this._endStep
) {
var stepMin = plen * 0.1 | 0,
startStep = this._startStep = (Math.random() * (plen / 3 * 2 | 0) | 0);
this._endStep = startStep + stepMin + ((Math.random() * (plen - startStep - stepMin) + 1) | 0);
this._lastChangeTime = currentTime;
}
// 親のポイント配列から取得範囲を切り出す
range = parent.points.slice(this._startStep, this._endStep);
rangeLen = range.length;
// 範囲からスプライン曲線の制御点を取得する
seg = (rangeLen - 1) / this._separate;
for (i = 0; i <= this._separate; i++) {
j = seg * i | 0;
points.push(range[j]);
}
// ノイズの実際の振り幅
c0 = points[0];
c1 = points[points.length - 1];
dx = c0.x - c1.x;
dy = c0.y - c1.y;
lineLength = Math.sqrt(dx * dx + dy * dy);
this._offset += Math.random() * param.speed;
this.points = this._filterApply(points, lineLength, rangeLen * 0.5 | 0, param.base, param.amplitude, this._offset);
},
_colorToString: function(alpha) {
var c = this.parent.color;
return this.parent.colorType === 'rgb' ?
'rgba(' + c.join(',') + ',' + alpha + ')' :
'hsla(' + c[0] + ',' + c[1] + '%,' + c[2] + '%,' + alpha + ')';
}
});
// Helpers
function extend() {
var t = {}, o, p, i, len;
for (i = 0, len = arguments.length; i < len; i++) {
o = arguments[i];
for (p in o) t[p] = o[p];
}
return t;
}
return Lightning;
})(window);
/**
* Point
*/
function Point(x, y, color, colorType) {
this.x = x;
this.y = y;
this.color = color;
this.colorType = colorType;
this.vx = Math.random() * (3 + 3) - 3;
this.vy = Math.random() * (3 + 3) - 3;
this._latest = { x: this.x, y: this.y };
}
Point._field = null;
Point.setField = function(x, y, width, height) {
Point._field = {
x: x,
y: y,
width: width,
height: height,
right: x + width,
bottom: y + height
};
};
Point.prototype = {
color: null,
colorType: 'rgb',
radius: 50,
alpha: 0.2,
dragging: false,
dying: false,
dead: false,
_mouse: null,
_latest: null,
_mouseDist: null,
_currentAlpha: 0,
_currentRadius: 0,
lengthSq: function() {
return this.x * this.x + this.y * this.y;
},
hitTest: function(mouse) {
var dx = mouse.x - this.x,
dy = mouse.y - this.y;
return dx * dx + dy * dy < this.radius * this.radius;
},
dragStart: function(mouse) {
if (this.hitTest(mouse)) {
this._mouse = mouse;
this._mouseDist = {
x: this.x - mouse.x,
y: this.y - mouse.y
};
this.dragging = true;
}
return this.dragging;
},
dragEnd: function() {
this.dragging = false;
this._mouse = this._mouseDist = null;
},
kill: function() {
this.dying = true;
this.radius = 0;
},
update: function(mouse) {
var field = Point._field,
radius = this.radius,
vlen, d;
if (this._mouse) {
this._latest.x = this.x;
this._latest.y = this.y;
this.x = this._mouse.x + this._mouseDist.x;
this.y = this._mouse.y + this._mouseDist.y;
this.vx = this.x - this._latest.x;
this.vy = this.y - this._latest.y;
} else {
this.x += this.vx;
this.y += this.vy;
this.vx *= 0.98;
this.vy *= 0.98;
}
vlen = Math.sqrt(this.vx * this.vx + this.vy * this.vy);
if (vlen && vlen > 20) {
this.vx /= vlen / 20;
this.vy /= vlen / 20;
}
if (this.x < field.x + radius) {
this.x = field.x + radius;
if (this.vx < 0) this.vx *= -1;
} else if (this.x > field.right - radius) {
this.x = field.right - radius;
if (this.vx > 0) this.vx *= -1;
}
if (this.y < field.y + radius) {
this.y = field.y + radius;
if (this.vy < 0) this.vy *= -1;
} else if (this.y > field.bottom - radius) {
this.y = field.bottom - radius;
if (this.vy > 0) this.vy *= -1;
}
// Alpha
d = this.alpha - this._currentAlpha;
if ((d < 0 ? -d : d) > 0.001) this._currentAlpha += d * 0.1;
// Radius
d = radius - this._currentRadius;
if ((d < 0 ? -d : d) > 0.01) {
this._currentRadius += d * 0.35;
} else if (this.dying) {
this.dead = true;
}
this._currentRadius *= Math.random() * (1 - 0.85) + 0.85;
},
draw: function(ctx) {
var radius = this._currentRadius;
var gradient = ctx.createRadialGradient(this.x, this.y, radius / 3, this.x, this.y, radius);
gradient.addColorStop(0, this._colorToString(this._currentAlpha));
gradient.addColorStop(1, this._colorToString(0));
ctx.fillStyle = gradient;
ctx.beginPath();
ctx.moveTo(this.x + radius, this.y);
ctx.arc(this.x, this.y, radius, 0, Math.PI * 2, false);
ctx.fill();
},
_colorToString: function(alpha) {
var c = this.color;
return this.colorType === 'rgb' ?
'rgba(' + c.join(',') + ',' + alpha + ')' :
'hsla(' + c[0] + ',' + c[1] + '%,' + c[2] + '%,' + alpha + ')';
}
};
(function() {
// Configs
var DRAG_POINT_NUM = 4,
DRAG_POINT_MAX_NUM = 8,
CHILD_NUM = 2,
LIHTNING_COLOR = [195, 100, 50]; // HSL
BACKGROUND_COLOR = 'rgba(0, 15, 20, 0.8)';
// Vars
var canvas, context,
canvasMinSize, centerX, centerY,
points = [],
mouse = { x: 0, y: 0 },
lightning,
grad,
i;
// Event Listeners
function resize(e) {
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
context = canvas.getContext('2d');
context.lineCap = 'round';
canvasMinSize = Math.min(canvas.width, canvas.height);
centerX = canvas.width * 0.5;
centerY = canvas.height * 0.5;
grad = context.createLinearGradient(0, 0, 0, canvas.height);
grad.addColorStop(0, 'hsla(195, 100%, 50%, 0.08)');
grad.addColorStop(0.5, 'hsla(195, 100%, 50%, 0)');
grad.addColorStop(1, 'hsla(195, 100%, 50%, 0.08)');
Point.setField(0, 0, canvas.width, canvas.height);
}
function mouseMove(e) {
mouse.x = e.clientX;
mouse.y = e.clientY;
var hit = false, i, len;
for (i = 0, len = points.length; i < len; i++) {
if (points[i].hitTest(mouse)) {
hit = true;
break;
}
}
document.body.style.cursor = hit ? 'pointer' : 'default';
}
function mouseDown(e) {
var i, len;
for (i = 0, len = points.length; i < len; i++) {
if (points[i].dragStart(mouse)) return;
}
for (i = 0; i < len; i++) {
if (points[i].hitTest(mouse)) {
if (len > 1) points.splice(i, 1);
return;
}
}
if (len < DRAG_POINT_MAX_NUM) {
points.push(createPoint(e.clientX, e.clientY));
} else {
for (i = 0; i < len - 2; i++) {
points[i].kill();
}
}
}
function mouseUp(e) {
for (var i = 0, len = points.length; i < len; i++) {
points[i].dragEnd(mouse);
}
}
function doubleClick(e) {
var i, len = points.length;
if (len < 3) return;
for (i = 0; i < len; i++) {
if (points[i].hitTest(mouse)) {
points[i].kill();
return;
}
}
}
// Functions
function createPoint(x, y) {
return new Point(x, y, LIHTNING_COLOR.slice(), 'hsl');
}
// Array sort callback
function sortPoints(p1, p2) {
return p1.lengthSq() - p2.lengthSq();
}
// Init
document.body.style.backgroundColor = BACKGROUND_COLOR;
canvas = document.getElementById('c');
window.addEventListener('resize', resize, false);
resize(null);
for (i = 0; i < DRAG_POINT_NUM; i++) {
points.push(createPoint(Math.random() * canvasMinSize + centerX - canvasMinSize * 0.5, Math.random() * canvasMinSize + centerY - canvasMinSize * 0.5));
}
lightning = new Lightning();
lightning.addParam(8, 10, 0.7, 0.01); // segumentsNum, noiseBase, amplitude, speed
lightning.addParam(16, 60, 0.5, 0.03);
lightning.colorType = 'hsl';
lightning.color = LIHTNING_COLOR.slice();
for (i = 0; i < CHILD_NUM; i++) {
lightning.createChild(80, 0.5, 0.06); // noiseBase, amplitude, speed
}
canvas.addEventListener('mousemove', mouseMove, false);
canvas.addEventListener('mousedown', mouseDown, false);
canvas.addEventListener('mouseup', mouseUp, false);
canvas.addEventListener('dblclick', doubleClick, false);
// Start update
var loop = function() {
var controls = [],
i, len, p;
context.save();
context.globalCompositeOperation = 'source-over';
context.fillStyle = BACKGROUND_COLOR;
context.fillRect(0, 0, canvas.width, canvas.height);
context.fillStyle = grad;
context.fillRect(0, 0, canvas.width, canvas.height);
context.restore();
context.globalCompositeOperation = 'lighter';
for (i = 0, len = points.length; i < len; i++) {
p = points[i];
p.update();
p.alpha = p.hitTest(mouse) ? 0.75 : 0.2;
p.draw(context);
if (p.dead) {
points.splice(i, 1);
i--;
len--;
continue;
}
if (!p.dying) controls.push(p);
}
// 原点からの距離でソート
controls.sort(sortPoints);
lightning.render(context, controls);
lightning.color[2] = Math.random() * (100 - 35) + 35;
requestAnimationFrame(loop);
};
loop();
})();
</script>
</body>
</html>