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HTML5 Canvas炫酷的火焰风暴动画
今天给大家分享一个用Canvas写的火焰风暴动画，实现效果如下：
怎么样，场面是不是很壮观，下面是代码实现，欢迎大家复制粘贴和吐槽。
<!DOCTYPE html>
<html lang="zh-cn">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>HTML5 Canvas炫酷的火焰风暴动画</title>
</head>
<body>
<script src="canvas.js"></script>
<canvas width="600" height="400"></canvas>
</body>
</html>下面是上面代码中引入的canvas.js的代码。
var c = document.createElement('canvas'),
ctx = c.getContext('2d'),
w = c.width = 600,
h = c.height = 400,
particles = [],
particleCount = 1000,
particlePath = 4,
pillars = [],
pillarCount = 110,
hue = 0,
hueRange = 60,
hueChange = 1,
gravity = 0.1,
lineWidth = 1,
lineCap = 'round',
PI = Math.PI,
TWO_PI = PI * 2;
function rand(min, max) {
return Math.random() * (max - min) + min;
}
function distance(a, b) {
var dx = a.x - b.x,
dy = a.y - b.y;
return Math.sqrt(dx * dx + dy * dy);
}
function Particle(opt) {
this.path = [];
this.reset();
}
Particle.prototype.reset = function () {
this.radius = 1;
this.x = rand(0, w);
this.y = 0;
this.vx = 0;
this.vy = 0;
this.hit = 0;
this.path.length = 0;
};
Particle.prototype.step = function () {
this.hit = 0;
this.path.unshift([this.x, this.y]);
if (this.path.length > particlePath) {
this.path.pop();
}
this.vy += gravity;
this.x += this.vx;
this.y += this.vy;
if (this.y > h + 10) {
this.reset();
}
var i = pillarCount;
while (i--) {
var pillar = pillars[i];
if (distance(this, pillar) < this.radius + pillar.renderRadius) {
this.vx = 0;
this.vy = 0;
this.vx += -(pillar.x - this.x) * rand(0.01, 0.03);
this.vy += -(pillar.y - this.y) * rand(0.01, 0.03);
pillar.radius -= 0.1;
this.hit = 1;
}
}
};
Particle.prototype.draw = function () {
ctx.beginPath();
ctx.moveTo(this.x, ~~this.y);
for (var i = 0, length = this.path.length; i < length; i++) {
var point = this.path[i];
ctx.lineTo(point[0], ~~point[1]);
}
ctx.strokeStyle = 'hsla(' + rand(hue + (this.x / 3), hue + (this.x / 3) + hueRange) + ', 50%, 30%, 0.3)';
ctx.stroke();
if (this.hit) {
ctx.beginPath();
ctx.arc(this.x, this.y, rand(1, 25), 0, TWO_PI);
ctx.fillStyle = 'hsla(' + rand(hue + (this.x / 3), hue + (this.x / 3) + hueRange) + ', 80%, 15%, 0.1)'
ctx.fill();
}
};
function Pillar() {
this.reset();
}
Pillar.prototype.reset = function () {
this.radius = rand(50, 100);
this.renderRadius = 0;
this.x = rand(0, w);
this.y = rand(h / 2 - h / 4, h);
this.active = 0;
};
Pillar.prototype.step = function () {
if (this.active) {
if (this.radius <= 1) {
this.reset();
} else {
this.renderRadius = this.radius;
}
} else {
if (this.renderRadius < this.radius) {
this.renderRadius += 0.5;
} else {
this.active = 1;
}
}
};
Pillar.prototype.draw = function () {
ctx.beginPath();
ctx.arc(this.x, this.y, this.renderRadius, 0, TWO_PI, false);
ctx.fill();
};
function init() {
ctx.lineWidth = lineWidth;
ctx.lineCap = lineCap;
var i = pillarCount;
while (i--) {
pillars.push(new Pillar());
}
document.body.appendChild(c);
loop();
}
function step() {
hue += hueChange;
if (particles.length < particleCount) {
particles.push(new Particle());
}
var i = particles.length;
while (i--) {
particles[i].step();
}
i = pillarCount;
while (i--) {
pillars[i].step();
}
}
function draw() {
ctx.fillStyle = 'hsla(0, 0%, 0%, 0.1)';
ctx.fillRect(0, 0, w, h);
ctx.globalCompositeOperation = 'lighter';
var i = particles.length;
while (i--) {
particles[i].draw();
}
ctx.globalCompositeOperation = 'source-over';
i = pillarCount;
ctx.fillStyle = 'rgba(20, 20, 20, 0.3)';
while (i--) {
pillars[i].draw();
}
}
function loop() {
requestAnimationFrame(loop);
step();
draw();
}
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