Untitled

mail@pastecode.io avatar
unknown
javascript
2 years ago
13 kB
1
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
    <head>
        <title>New Document</title>
        <meta name="Generator" content="EditPlus" />
        <meta name="Author" content="" />
        <meta name="Keywords" content="" />
        <meta name="Description" content="" />
        <style>
            html,
            body {
                height: 100%;
                padding: 0;
                margin: 0;
                background: #000;
            }
            canvas {
                position: absolute;
                width: 100%;
                height: 100%;
            }
        </style>
    </head>

    <body>
        <canvas id="pinkboard"></canvas>
        <script>
            /*
             * Settings
             */
            var settings = {
                particles: {
                    length: 500, // maximum amount of particles
                    duration: 2, // particle duration in sec
                    velocity: 100, // particle velocity in pixels/sec
                    effect: -0.75, // play with this for a nice effect
                    size: 30, // particle size in pixels
                },
            };

            /*
             * RequestAnimationFrame polyfill by Erik Möller
             */
            (function () {
                var b = 0;
                var c = ["ms", "moz", "webkit", "o"];
                for (
                    var a = 0;
                    a < c.length && !window.requestAnimationFrame;
                    ++a
                ) {
                    window.requestAnimationFrame =
                        window[c[a] + "RequestAnimationFrame"];
                    window.cancelAnimationFrame =
                        window[c[a] + "CancelAnimationFrame"] ||
                        window[c[a] + "CancelRequestAnimationFrame"];
                }
                if (!window.requestAnimationFrame) {
                    window.requestAnimationFrame = function (h, e) {
                        var d = new Date().getTime();
                        var f = Math.max(0, 16 - (d - b));
                        var g = window.setTimeout(function () {
                            h(d + f);
                        }, f);
                        b = d + f;
                        return g;
                    };
                }
                if (!window.cancelAnimationFrame) {
                    window.cancelAnimationFrame = function (d) {
                        clearTimeout(d);
                    };
                }
            })();

            /*
             * Point class
             */
            var Point = (function () {
                function Point(x, y) {
                    this.x = typeof x !== "undefined" ? x : 0;
                    this.y = typeof y !== "undefined" ? y : 0;
                }
                Point.prototype.clone = function () {
                    return new Point(this.x, this.y);
                };
                Point.prototype.length = function (length) {
                    if (typeof length == "undefined")
                        return Math.sqrt(this.x * this.x + this.y * this.y);
                    this.normalize();
                    this.x *= length;
                    this.y *= length;
                    return this;
                };
                Point.prototype.normalize = function () {
                    var length = this.length();
                    this.x /= length;
                    this.y /= length;
                    return this;
                };
                return Point;
            })();

            /*
             * Particle class
             */
            var Particle = (function () {
                function Particle() {
                    this.position = new Point();
                    this.velocity = new Point();
                    this.acceleration = new Point();
                    this.age = 0;
                }
                Particle.prototype.initialize = function (x, y, dx, dy) {
                    this.position.x = x;
                    this.position.y = y;
                    this.velocity.x = dx;
                    this.velocity.y = dy;
                    this.acceleration.x = dx * settings.particles.effect;
                    this.acceleration.y = dy * settings.particles.effect;
                    this.age = 0;
                };
                Particle.prototype.update = function (deltaTime) {
                    this.position.x += this.velocity.x * deltaTime;
                    this.position.y += this.velocity.y * deltaTime;
                    this.velocity.x += this.acceleration.x * deltaTime;
                    this.velocity.y += this.acceleration.y * deltaTime;
                    this.age += deltaTime;
                };
                Particle.prototype.draw = function (context, image) {
                    function ease(t) {
                        return --t * t * t + 1;
                    }
                    var size =
                        image.width *
                        ease(this.age / settings.particles.duration);
                    context.globalAlpha =
                        1 - this.age / settings.particles.duration;
                    context.drawImage(
                        image,
                        this.position.x - size / 2,
                        this.position.y - size / 2,
                        size,
                        size
                    );
                };
                return Particle;
            })();

            /*
             * ParticlePool class
             */
            var ParticlePool = (function () {
                var particles,
                    firstActive = 0,
                    firstFree = 0,
                    duration = settings.particles.duration;

                function ParticlePool(length) {
                    // create and populate particle pool
                    particles = new Array(length);
                    for (var i = 0; i < particles.length; i++)
                        particles[i] = new Particle();
                }
                ParticlePool.prototype.add = function (x, y, dx, dy) {
                    particles[firstFree].initialize(x, y, dx, dy);

                    // handle circular queue
                    firstFree++;
                    if (firstFree == particles.length) firstFree = 0;
                    if (firstActive == firstFree) firstActive++;
                    if (firstActive == particles.length) firstActive = 0;
                };
                ParticlePool.prototype.update = function (deltaTime) {
                    var i;

                    // update active particles
                    if (firstActive < firstFree) {
                        for (i = firstActive; i < firstFree; i++)
                            particles[i].update(deltaTime);
                    }
                    if (firstFree < firstActive) {
                        for (i = firstActive; i < particles.length; i++)
                            particles[i].update(deltaTime);
                        for (i = 0; i < firstFree; i++)
                            particles[i].update(deltaTime);
                    }

                    // remove inactive particles
                    while (
                        particles[firstActive].age >= duration &&
                        firstActive != firstFree
                    ) {
                        firstActive++;
                        if (firstActive == particles.length) firstActive = 0;
                    }
                };
                ParticlePool.prototype.draw = function (context, image) {
                    // draw active particles
                    if (firstActive < firstFree) {
                        for (i = firstActive; i < firstFree; i++)
                            particles[i].draw(context, image);
                    }
                    if (firstFree < firstActive) {
                        for (i = firstActive; i < particles.length; i++)
                            particles[i].draw(context, image);
                        for (i = 0; i < firstFree; i++)
                            particles[i].draw(context, image);
                    }
                };
                return ParticlePool;
            })();

            /*
             * Putting it all together
             */
            (function (canvas) {
                var context = canvas.getContext("2d"),
                    particles = new ParticlePool(settings.particles.length),
                    particleRate =
                        settings.particles.length / settings.particles.duration, // particles/sec
                    time;

                // get point on heart with -PI <= t <= PI
                function pointOnHeart(t) {
                    return new Point(
                        160 * Math.pow(Math.sin(t), 3),
                        130 * Math.cos(t) -
                            50 * Math.cos(2 * t) -
                            20 * Math.cos(3 * t) -
                            10 * Math.cos(4 * t) +
                            25
                    );
                }

                // creating the particle image using a dummy canvas
                var image = (function () {
                    var canvas = document.createElement("canvas"),
                        context = canvas.getContext("2d");
                    canvas.width = settings.particles.size;
                    canvas.height = settings.particles.size;
                    // helper function to create the path
                    function to(t) {
                        var point = pointOnHeart(t);
                        point.x =
                            settings.particles.size / 2 +
                            (point.x * settings.particles.size) / 350;
                        point.y =
                            settings.particles.size / 2 -
                            (point.y * settings.particles.size) / 350;
                        return point;
                    }
                    // create the path
                    context.beginPath();
                    var t = -Math.PI;
                    var point = to(t);
                    context.moveTo(point.x, point.y);
                    while (t < Math.PI) {
                        t += 0.01; // baby steps!
                        point = to(t);
                        context.lineTo(point.x, point.y);
                    }
                    context.closePath();
                    // create the fill
                    context.fillStyle = "#e4e4e4";
                    context.fill();
                    // create the image
                    var image = new Image();
                    image.src = canvas.toDataURL();
                    return image;
                })();

                // render that thing!
                function render() {
                    // next animation frame
                    requestAnimationFrame(render);

                    // update time
                    var newTime = new Date().getTime() / 1000,
                        deltaTime = newTime - (time || newTime);
                    time = newTime;

                    // clear canvas
                    context.clearRect(0, 0, canvas.width, canvas.height);

                    // create new particles
                    var amount = particleRate * deltaTime;
                    for (var i = 0; i < amount; i++) {
                        var pos = pointOnHeart(
                            Math.PI - 2 * Math.PI * Math.random()
                        );
                        var dir = pos
                            .clone()
                            .length(settings.particles.velocity);
                        particles.add(
                            canvas.width / 2 + pos.x,
                            canvas.height / 2 - pos.y,
                            dir.x,
                            -dir.y
                        );
                    }

                    // update and draw particles
                    particles.update(deltaTime);
                    particles.draw(context, image);
                }

                // handle (re-)sizing of the canvas
                function onResize() {
                    canvas.width = canvas.clientWidth;
                    canvas.height = canvas.clientHeight;
                }
                window.onresize = onResize;

                // delay rendering bootstrap
                setTimeout(function () {
                    onResize();
                    render();
                }, 10);
            })(document.getElementById("pinkboard"));
        </script>
    </body>
</html>