canvas煙花錦集
阿新 • • 發佈:2018-01-23
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canvas可以實現不同動畫效果,本文主要記錄幾種不同節日煙花效果實現。
實現一
效果地址
html
<canvas id="canvas"></canvas>
css
body {
background: #000;
margin: 0;
}
canvas {
cursor: crosshair;
display: block;
}
js
// when animating on canvas, it is best to use requestAnimationFrame instead of setTimeout or setInterval // not supported in all browsers though and sometimes needs a prefix, so we need a shim window.requestAnimFrame = (function () { return window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || function (callback) { window.setTimeout(callback, 1000 / 60); }; })(); // now we will setup our basic variables for the demo var canvas = document.getElementById('canvas'), ctx = canvas.getContext('2d'), // full screen dimensions cw = window.innerWidth, ch = window.innerHeight, // firework collection fireworks = [], // particle collection particles = [], // starting hue hue = 120, // when launching fireworks with a click, too many get launched at once without a limiter, one launch per 5 loop ticks limiterTotal = 5, limiterTick = 0, // this will time the auto launches of fireworks, one launch per 80 loop ticks timerTotal = 80, timerTick = 0, mousedown = false, // mouse x coordinate, mx, // mouse y coordinate my; // set canvas dimensions canvas.width = cw; canvas.height = ch; // now we are going to setup our function placeholders for the entire demo // get a random number within a range function random(min, max) { return Math.random() * (max - min) + min; } // calculate the distance between two points function calculateDistance(p1x, p1y, p2x, p2y) { var xDistance = p1x - p2x, yDistance = p1y - p2y; return Math.sqrt(Math.pow(xDistance, 2) + Math.pow(yDistance, 2)); } // create firework function Firework(sx, sy, tx, ty) { // actual coordinates this.x = sx; this.y = sy; // starting coordinates this.sx = sx; this.sy = sy; // target coordinates this.tx = tx; this.ty = ty; // distance from starting point to target this.distanceToTarget = calculateDistance(sx, sy, tx, ty); this.distanceTraveled = 0; // track the past coordinates of each firework to create a trail effect, increase the coordinate count to create more prominent trails this.coordinates = []; this.coordinateCount = 3; // populate initial coordinate collection with the current coordinates while (this.coordinateCount--) { this.coordinates.push([this.x, this.y]); } this.angle = Math.atan2(ty - sy, tx - sx); this.speed = 2; this.acceleration = 1.05; this.brightness = random(50, 70); // circle target indicator radius this.targetRadius = 1; } // update firework Firework.prototype.update = function (index) { // remove last item in coordinates array this.coordinates.pop(); // add current coordinates to the start of the array this.coordinates.unshift([this.x, this.y]); // cycle the circle target indicator radius if (this.targetRadius < 8) { this.targetRadius += 0.3; } else { this.targetRadius = 1; } // speed up the firework this.speed *= this.acceleration; // get the current velocities based on angle and speed var vx = Math.cos(this.angle) * this.speed, vy = Math.sin(this.angle) * this.speed; // how far will the firework have traveled with velocities applied? this.distanceTraveled = calculateDistance(this.sx, this.sy, this.x + vx, this.y + vy); // if the distance traveled, including velocities, is greater than the initial distance to the target, then the target has been reached if (this.distanceTraveled >= this.distanceToTarget) { createParticles(this.tx, this.ty); // remove the firework, use the index passed into the update function to determine which to remove fireworks.splice(index, 1); } else { // target not reached, keep traveling this.x += vx; this.y += vy; } } // draw firework Firework.prototype.draw = function () { ctx.beginPath(); // move to the last tracked coordinate in the set, then draw a line to the current x and y ctx.moveTo(this.coordinates[this.coordinates.length - 1][0], this.coordinates[this.coordinates.length - 1][ 1 ]); ctx.lineTo(this.x, this.y); ctx.strokeStyle = 'hsl(' + hue + ', 100%, ' + this.brightness + '%)'; ctx.stroke(); ctx.beginPath(); // draw the target for this firework with a pulsing circle ctx.arc(this.tx, this.ty, this.targetRadius, 0, Math.PI * 2); ctx.stroke(); } // create particle function Particle(x, y) { this.x = x; this.y = y; // track the past coordinates of each particle to create a trail effect, increase the coordinate count to create more prominent trails this.coordinates = []; this.coordinateCount = 5; while (this.coordinateCount--) { this.coordinates.push([this.x, this.y]); } // set a random angle in all possible directions, in radians this.angle = random(0, Math.PI * 2); this.speed = random(1, 10); // friction will slow the particle down this.friction = 0.95; // gravity will be applied and pull the particle down this.gravity = 1; // set the hue to a random number +-20 of the overall hue variable this.hue = random(hue - 20, hue + 20); this.brightness = random(50, 80); this.alpha = 1; // set how fast the particle fades out this.decay = random(0.015, 0.03); } // update particle Particle.prototype.update = function (index) { // remove last item in coordinates array this.coordinates.pop(); // add current coordinates to the start of the array this.coordinates.unshift([this.x, this.y]); // slow down the particle this.speed *= this.friction; // apply velocity this.x += Math.cos(this.angle) * this.speed; this.y += Math.sin(this.angle) * this.speed + this.gravity; // fade out the particle this.alpha -= this.decay; // remove the particle once the alpha is low enough, based on the passed in index if (this.alpha <= this.decay) { particles.splice(index, 1); } } // draw particle Particle.prototype.draw = function () { ctx.beginPath(); // move to the last tracked coordinates in the set, then draw a line to the current x and y ctx.moveTo(this.coordinates[this.coordinates.length - 1][0], this.coordinates[this.coordinates.length - 1][ 1 ]); ctx.lineTo(this.x, this.y); ctx.strokeStyle = 'hsla(' + this.hue + ', 100%, ' + this.brightness + '%, ' + this.alpha + ')'; ctx.stroke(); } // create particle group/explosion function createParticles(x, y) { // increase the particle count for a bigger explosion, beware of the canvas performance hit with the increased particles though var particleCount = 30; while (particleCount--) { particles.push(new Particle(x, y)); } } // main demo loop function loop() { // this function will run endlessly with requestAnimationFrame requestAnimFrame(loop); // increase the hue to get different colored fireworks over time hue += 0.5; // normally, clearRect() would be used to clear the canvas // we want to create a trailing effect though // setting the composite operation to destination-out will allow us to clear the canvas at a specific opacity, rather than wiping it entirely ctx.globalCompositeOperation = 'destination-out'; // decrease the alpha property to create more prominent trails ctx.fillStyle = 'rgba(0, 0, 0, 0.5)'; ctx.fillRect(0, 0, cw, ch); // change the composite operation back to our main mode // lighter creates bright highlight points as the fireworks and particles overlap each other ctx.globalCompositeOperation = 'lighter'; var text = "HAPPY NEW YEAR !"; ctx.font = "50px sans-serif"; var textData = ctx.measureText(text); ctx.fillStyle = "rgba(" + parseInt(random(0, 255)) + "," + parseInt(random(0, 255)) + "," + parseInt(random(0, 255)) + ",0.3)"; ctx.fillText(text, cw / 2 - textData.width / 2, ch / 2); // loop over each firework, draw it, update it var i = fireworks.length; while (i--) { fireworks[i].draw(); fireworks[i].update(i); } // loop over each particle, draw it, update it var i = particles.length; while (i--) { particles[i].draw(); particles[i].update(i); } // launch fireworks automatically to random coordinates, when the mouse isn't down if (timerTick >= timerTotal) { if (!mousedown) { // start the firework at the bottom middle of the screen, then set the random target coordinates, the random y coordinates will be set within the range of the top half of the screen for (var h = 0; h < 50; h++) { fireworks.push(new Firework(cw / 2, ch / 2, random(0, cw), random(0, ch))); } timerTick = 0; } } else { timerTick++; } // limit the rate at which fireworks get launched when mouse is down if (limiterTick >= limiterTotal) { if (mousedown) { // start the firework at the bottom middle of the screen, then set the current mouse coordinates as the target fireworks.push(new Firework(cw / 2, ch / 2, mx, my)); limiterTick = 0; } } else { limiterTick++; } } // mouse event bindings // update the mouse coordinates on mousemove canvas.addEventListener('mousemove', function (e) { mx = e.pageX - canvas.offsetLeft; my = e.pageY - canvas.offsetTop; }); // toggle mousedown state and prevent canvas from being selected canvas.addEventListener('mousedown', function (e) { e.preventDefault(); mousedown = true; }); canvas.addEventListener('mouseup', function (e) { e.preventDefault(); mousedown = false; }); // once the window loads, we are ready for some fireworks! window.onload = loop;
實現二
效果地址
html
<canvas></canvas>
<h1>201<span>8</span></h1>
css
html, body { padding: 0px; margin: 0px; background: #222; font-family: 'Karla', sans-serif; color: #FFF; height: 100%; overflow: hidden; } h1 { z-index: 1000; position: fixed; top: 50%; left: 50%; transform: translateX(-50%) translateY(-100%); font-size: 58px; overflow: hidden; } span { position: relative; display: inline-block; animation: drop 0.75s ease 0s; } canvas { width: 100%; height: 100%; } @keyframes drop { 0% { transform: translateY(-100px); opacity: 0; } 90% { opacity: 1; transform: translateY(10px); } 100% { transform: translateY(0px); } }
js
var ctx = document.querySelector('canvas').getContext('2d') ctx.canvas.width = window.innerWidth ctx.canvas.height = window.innerHeight var sparks = [] var fireworks = [] var i = 20; while (i--) { fireworks.push( new Firework(Math.random() * window.innerWidth, window.innerHeight * Math.random()) ) } render() function render() { setTimeout(render, 1000 / 60) ctx.fillStyle = 'rgba(0, 0, 0, 0.1)'; ctx.fillRect(0, 0, ctx.canvas.width, ctx.canvas.height) for (var firework of fireworks) { if (firework.dead) continue firework.move() firework.draw() } for (var spark of sparks) { if (spark.dead) continue spark.move() spark.draw() } if (Math.random() < 0.05) { fireworks.push(new Firework()) } } function Spark(x, y, color) { this.x = x this.y = y this.dir = Math.random() * (Math.PI * 2) this.dead = false this.color = color this.speed = Math.random() * 3 + 3; this.walker = new Walker({ radius: 20, speed: 0.25 }) this.gravity = 0.25 this.dur = this.speed / 0.1 this.move = function () { this.dur-- if (this.dur < 0) this.dead = true if (this.speed < 0) return if (this.speed > 0) this.speed -= 0.1 var walk = this.walker.step() this.x += Math.cos(this.dir + walk) * this.speed this.y += Math.sin(this.dir + walk) * this.speed this.y += this.gravity this.gravity += 0.05 } this.draw = function () { drawCircle(this.x, this.y, 3, this.color) } } function Firework(x, y) { this.xmove = new Walker({ radius: 10, speed: 0.5 }) this.x = x || Math.random() * ctx.canvas.width this.y = y || ctx.canvas.height this.height = Math.random() * ctx.canvas.height / 2 this.dead = false this.color = randomColor() this.move = function () { this.x += this.xmove.step() if (this.y > this.height) this.y -= 1; else this.burst() } this.draw = function () { drawCircle(this.x, this.y, 1, this.color) } this.burst = function () { this.dead = true var i = 100; while (i--) sparks.push(new Spark(this.x, this.y, this.color)) } } function drawCircle(x, y, radius, color) { color = color || '#FFF' ctx.fillStyle = color ctx.fillRect(x - radius / 2, y - radius / 2, radius, radius) } function randomColor() { return ['#6ae5ab', '#88e3b2', '#36b89b', '#7bd7ec', '#66cbe1'][Math.floor(Math.random() * 5)]; } function Walker(options) { this.step = function () { this.direction = Math.sign(this.target) * this.speed this.value += this.direction this.target ? this.target -= this.direction : (this.value) ? (this.wander) ? this.target = this.newTarget() : this.target = -this.value : this.target = this.newTarget() return this.direction } this.newTarget = function () { return Math.round(Math.random() * (this.radius * 2) - this.radius) } this.start = 0 this.value = 0 this.radius = options.radius this.target = this.newTarget() this.direction = Math.sign(this.target) this.wander = options.wander this.speed = options.speed || 1 }
實現三
效果地址
html
<canvas id="cas" style="background-color:rgba(0,5,24,1)" width="1235" height="680">瀏覽器不支持canvas</canvas>
<div class="city">
<img src="city.png" alt="">
</div>
<img src="moon.png" alt="" id="moon" style="visibility: hidden;">
<div style="display:none">
<div class="shape">新年快樂</div>
<div class="shape">闔家歡樂</div>
<div class="shape">萬事如意</div>
<div class="shape">心想事成</div>
</div>
css
body {
margin: 0;
padding: 0;
overflow: hidden;
}
.city {
width: 100%;
position: fixed;
bottom: 0px;
z-index: 100;
}
.city img {
width: 100%;
}
js
var canvas = document.getElementById("cas");
var ocas = document.createElement("canvas");
var octx = ocas.getContext("2d");
var ctx = canvas.getContext("2d");
ocas.width = canvas.width = window.innerWidth;
ocas.height = canvas.height = window.innerHeight;
var bigbooms = [];
window.onload = function () {
initAnimate()
}
function initAnimate() {
drawBg();
lastTime = new Date();
animate();
}
var lastTime;
function animate() {
ctx.save();
ctx.fillStyle = "rgba(0,5,24,0.1)";
ctx.fillRect(0, 0, canvas.width, canvas.height);
ctx.restore();
var newTime = new Date();
if (newTime - lastTime > 500 + (window.innerHeight - 767) / 2) {
var random = Math.random() * 100 > 2 ? true : false;
var x = getRandom(canvas.width / 5, canvas.width * 4 / 5);
var y = getRandom(50, 200);
if (random) {
var bigboom = new Boom(getRandom(canvas.width / 3, canvas.width * 2 / 3), 2, "#FFF", {
x: x,
y: y
});
bigbooms.push(bigboom)
} else {
var bigboom = new Boom(getRandom(canvas.width / 3, canvas.width * 2 / 3), 2, "#FFF", {
x: canvas.width / 2,
y: 200
}, document.querySelectorAll(".shape")[parseInt(getRandom(0, document.querySelectorAll(
".shape").length))]);
bigbooms.push(bigboom)
}
lastTime = newTime;
}
stars.foreach(function () {
this.paint();
})
drawMoon();
bigbooms.foreach(function (index) {
var that = this;
if (!this.dead) {
this._move();
this._drawLight();
} else {
this.booms.foreach(function (index) {
if (!this.dead) {
this.moveTo(index);
} else if (index === that.booms.length - 1) {
bigbooms[bigbooms.indexOf(that)] = null;
}
})
}
});
raf(animate);
}
function drawMoon() {
var moon = document.getElementById("moon");
var centerX = canvas.width - 200,
centerY = 100,
width = 80;
if (moon.complete) {
ctx.drawImage(moon, centerX, centerY, width, width)
} else {
moon.onload = function () {
ctx.drawImage(moon, centerX, centerY, width, width)
}
}
var index = 0;
for (var i = 0; i < 10; i++) {
ctx.save();
ctx.beginPath();
ctx.arc(centerX + width / 2, centerY + width / 2, width / 2 + index, 0, 2 * Math.PI);
ctx.fillStyle = "rgba(240,219,120,0.005)";
index += 2;
ctx.fill();
ctx.restore();
}
}
Array.prototype.foreach = function (callback) {
for (var i = 0; i < this.length; i++) {
if (this[i] !== null) callback.apply(this[i], [i])
}
}
var raf = window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame ||
window.oRequestAnimationFrame || window.msRequestAnimationFrame || function (callback) {
window.setTimeout(callback, 1000 / 60);
};
canvas.onclick = function () {
var x = event.clientX;
var y = event.clientY;
var bigboom = new Boom(getRandom(canvas.width / 3, canvas.width * 2 / 3), 2, "#FFF", {
x: x,
y: y
});
bigbooms.push(bigboom)
}
var Boom = function (x, r, c, boomArea, shape) {
this.booms = [];
this.x = x;
this.y = (canvas.height + r);
this.r = r;
this.c = c;
this.shape = shape || false;
this.boomArea = boomArea;
this.theta = 0;
this.dead = false;
this.ba = parseInt(getRandom(80, 200));
}
Boom.prototype = {
_paint: function () {
ctx.save();
ctx.beginPath();
ctx.arc(this.x, this.y, this.r, 0, 2 * Math.PI);
ctx.fillStyle = this.c;
ctx.fill();
ctx.restore();
},
_move: function () {
var dx = this.boomArea.x - this.x,
dy = this.boomArea.y - this.y;
this.x = this.x + dx * 0.01;
this.y = this.y + dy * 0.01;
if (Math.abs(dx) <= this.ba && Math.abs(dy) <= this.ba) {
if (this.shape) {
this._shapBoom();
} else this._boom();
this.dead = true;
} else {
this._paint();
}
},
_drawLight: function () {
ctx.save();
ctx.fillStyle = "rgba(255,228,150,0.3)";
ctx.beginPath();
ctx.arc(this.x, this.y, this.r + 3 * Math.random() + 1, 0, 2 * Math.PI);
ctx.fill();
ctx.restore();
},
_boom: function () {
var fragNum = getRandom(30, 200);
var style = getRandom(0, 10) >= 5 ? 1 : 2;
var color;
if (style === 1) {
color = {
a: parseInt(getRandom(128, 255)),
b: parseInt(getRandom(128, 255)),
c: parseInt(getRandom(128, 255))
}
}
var fanwei = parseInt(getRandom(300, 400));
for (var i = 0; i < fragNum; i++) {
if (style === 2) {
color = {
a: parseInt(getRandom(128, 255)),
b: parseInt(getRandom(128, 255)),
c: parseInt(getRandom(128, 255))
}
}
var a = getRandom(-Math.PI, Math.PI);
var x = getRandom(0, fanwei) * Math.cos(a) + this.x;
var y = getRandom(0, fanwei) * Math.sin(a) + this.y;
var radius = getRandom(0, 2)
var frag = new Frag(this.x, this.y, radius, color, x, y);
this.booms.push(frag);
}
},
_shapBoom: function () {
var that = this;
putValue(ocas, octx, this.shape, 5, function (dots) {
var dx = canvas.width / 2 - that.x;
var dy = canvas.height / 2 - that.y;
for (var i = 0; i < dots.length; i++) {
color = {
a: dots[i].a,
b: dots[i].b,
c: dots[i].c
}
var x = dots[i].x;
var y = dots[i].y;
var radius = 1;
var frag = new Frag(that.x, that.y, radius, color, x - dx, y - dy);
that.booms.push(frag);
}
})
}
}
function putValue(canvas, context, ele, dr, callback) {
context.clearRect(0, 0, canvas.width, canvas.height);
var img = new Image();
if (ele.innerHTML.indexOf("img") >= 0) {
img.src = ele.getElementsByTagName("img")[0].src;
imgload(img, function () {
context.drawImage(img, canvas.width / 2 - img.width / 2, canvas.height / 2 - img.width / 2);
dots = getimgData(canvas, context, dr);
callback(dots);
})
} else {
var text = ele.innerHTML;
context.save();
var fontSize = 200;
context.font = fontSize + "px 宋體 bold";
context.textAlign = "center";
context.textBaseline = "middle";
context.fillStyle = "rgba(" + parseInt(getRandom(128, 255)) + "," + parseInt(getRandom(128, 255)) + "," +
parseInt(getRandom(128, 255)) + " , 1)";
context.fillText(text, canvas.width / 2, canvas.height / 2);
context.restore();
dots = getimgData(canvas, context, dr);
callback(dots);
}
}
function imgload(img, callback) {
if (img.complete) {
callback.call(img);
} else {
img.onload = function () {
callback.call(this);
}
}
}
function getimgData(canvas, context, dr) {
var imgData = context.getImageData(0, 0, canvas.width, canvas.height);
context.clearRect(0, 0, canvas.width, canvas.height);
var dots = [];
for (var x = 0; x < imgData.width; x += dr) {
for (var y = 0; y < imgData.height; y += dr) {
var i = (y * imgData.width + x) * 4;
if (imgData.data[i + 3] > 128) {
var dot = {
x: x,
y: y,
a: imgData.data[i],
b: imgData.data[i + 1],
c: imgData.data[i + 2]
};
dots.push(dot);
}
}
}
return dots;
}
function getRandom(a, b) {
return Math.random() * (b - a) + a;
}
var maxRadius = 1,
stars = [];
function drawBg() {
for (var i = 0; i < 100; i++) {
var r = Math.random() * maxRadius;
var x = Math.random() * canvas.width;
var y = Math.random() * 2 * canvas.height - canvas.height;
var star = new Star(x, y, r);
stars.push(star);
star.paint()
}
}
var Star = function (x, y, r) {
this.x = x;
this.y = y;
this.r = r;
}
Star.prototype = {
paint: function () {
ctx.save();
ctx.beginPath();
ctx.arc(this.x, this.y, this.r, 0, 2 * Math.PI);
ctx.fillStyle = "rgba(255,255,255," + this.r + ")";
ctx.fill();
ctx.restore();
}
}
var focallength = 250;
var Frag = function (centerX, centerY, radius, color, tx, ty) {
this.tx = tx;
this.ty = ty;
this.x = centerX;
this.y = centerY;
this.dead = false;
this.centerX = centerX;
this.centerY = centerY;
this.radius = radius;
this.color = color;
}
Frag.prototype = {
paint: function () {
ctx.save();
ctx.beginPath();
ctx.arc(this.x, this.y, this.radius, 0, 2 * Math.PI);
ctx.fillStyle = "rgba(" + this.color.a + "," + this.color.b + "," + this.color.c + ",1)";
ctx.fill()
ctx.restore();
},
moveTo: function (index) {
this.ty = this.ty + 0.3;
var dx = this.tx - this.x,
dy = this.ty - this.y;
this.x = Math.abs(dx) < 0.1 ? this.tx : (this.x + dx * 0.1);
this.y = Math.abs(dy) < 0.1 ? this.ty : (this.y + dy * 0.1);
if (dx === 0 && Math.abs(dy) <= 80) {
this.dead = true;
}
this.paint();
}
}
總結
幾種不同canvas實現煙花動畫,基本分為煙火類和碎屑類展現煙花的不同狀態。
同時,祝大家新年快樂!
原文地址:http://www.bestvist.com/2018/01/15/canvas-fireworks/
canvas煙花錦集