H5炫酷特效系列2——canvas特效-炫酷的心_canvas动效

作者：笔触狂放9 | 2024-05-21 15:54:06
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canvas动效
之前已经有了一个满屏幕红心的案例，这次带来一个更加炫酷的心型炫酷动效，直接上图，有兴趣的就继续往下看，没兴趣直接过。
这里写图片描述
屏幕上眼花缭乱的心，不停的冲击着你的视线，让那些少女心砰砰直跳，绝对表白利器，同志们可以直接拿去给中意的姑娘看哦。
直接将下面的代码复制运行就可以看到效果：
<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8">
  <title>炫酷的心</title>
  <style type="text/css">
    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 src="https://code.jquery.com/jquery-3.2.1.min.js"></script>
  <script type="text/javascript">
    var settings = {
        particles: {
          length: 500, //最大粒子数
          duration: 2, //粒子持续时间
          velocity: 100, //粒子速度，像素/秒
          effect: -0.75,
          size: 30, //粒子大小
        }
      };
      (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)
          }
        }
      }());

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

      function ParticlePool(length) {
        // 创建和填充粒子库
        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);

        // 处理循环队列
        firstFree++;
        if (firstFree == particles.length) firstFree = 0;
        if (firstActive == firstFree) firstActive++;
        if (firstActive == particles.length) firstActive = 0;
      };
      ParticlePool.prototype.update = function(deltaTime) {
        var i;

        // 更新活动粒子
        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);
        }

        // 删除不活动的粒子
        while (particles[firstActive].age >= duration && firstActive != firstFree) {
          firstActive++;
          if (firstActive == particles.length) firstActive = 0;
        }


      };
      ParticlePool.prototype.draw = function(context, image) {
        // 画活动粒子
        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;
    })();
    (function(canvas) {
      var context = canvas.getContext('2d'),
        particles = new ParticlePool(settings.particles.length),
        particleRate = settings.particles.length / settings.particles.duration, // particles/sec
        time;

      // 获取heart点位 -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
        );
      }

      // 使用canvas创建粒子图像
      var image = (function() {
        var canvas = document.createElement('canvas'),
          context = canvas.getContext('2d');
        canvas.width = settings.particles.size;
        canvas.height = settings.particles.size;
        // 创建路径的辅助函数
        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;
        }
        // 创建路径
        context.beginPath();
        var t = -Math.PI;
        var point = to(t);
        context.moveTo(point.x, point.y);
        while (t < Math.PI) {
          t += 0.01;
          point = to(t);
          context.lineTo(point.x, point.y);
        }
        context.closePath();
        // 填充
        context.fillStyle = '#ea80b0';
        context.fill();
        // 创建图片
        var image = new Image();
        image.src = canvas.toDataURL();
        return image;
      })();

      // 渲染
      function render() {
        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);

        // 创建新的粒子
        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);
        }

        // 更新并绘制
        particles.update(deltaTime);
        particles.draw(context, image);
      }

      // 处理canvas大小
      function onResize() {
        canvas.width = canvas.clientWidth;
        canvas.height = canvas.clientHeight;
      }
      window.onresize = onResize;

      // 延迟渲染
      setTimeout(function() {
        onResize();
        render();
      }, 10);
    })(document.getElementById('pinkboard'));
  </script>
</body>

</html>
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