爱心代码，赶紧安排给你的crush吧

于 2022-12-18 17:32:48 发布
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文章标签： javascript html 前端
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本文链接：https://blog.youkuaiyun.com/qq_67445494/article/details/128364018
版权
这段代码展示了如何使用RequestAnimationFrame和Point、Particle、ParticlePool等类创建一个爱心形状的粒子动画，通过数学函数控制粒子轨迹。粒子在canvas上按设定速度和效果生成，形成动态视觉效果。

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爱心代码

在这里插入图片描述

my special

/*

  • 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 = ‘#ea80b0’;
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’));

my special

/*

  • 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 = ‘#ea80b0’;
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’));

`ML>
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