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html5 canvas圣诞节雪花飞舞场景动画特效

作者/代码整理:  (源码已亲测,不会安装的可以向QQ1915635791要安装视频教程) 发布日期:2023-01-06
html5 canvas圣诞节雪花飞舞场景动画特效
html5 canvas圣诞节雪花飞舞场景动画特效是一款很漂亮的雪花从天空中飘落动画效果。


js代码

<script>
var c = document.getElementById('canvas'), 
    $ = c.getContext("2d"),
	 w = c.width = window.innerWidth, 
    h = c.height = window.innerHeight;

function makeItSnow() {
  var snow,  
		arr = [],
		num = 1500,
		tsc = 1, 
		sp = 1;
		sc = 1.3, 
		t = 0, 
		mv = 20, 
		min = 1;
	for (var i = 0; i < num; ++i) {
      snow = new Flake();
      snow.y = Math.random() * (h + 50);
      snow.x = Math.random() * w;
      snow.t = Math.random() * (Math.PI * 2);
      snow.sz = (100 / (10 + (Math.random() * 100))) * sc;
      snow.sp = (Math.pow(snow.sz * .8, 2) * .15) * sp;
      snow.sp = snow.sp < min ? min : snow.sp;
      arr.push(snow);
    }
  	go();
  	function go(){
   	window.requestAnimationFrame(go);
      $.clearRect(0, 0, w, h);
      $.fillRect(0, 0, w, h);
      $.fill();
        for (var i = 0; i < arr.length; ++i) {
          f = arr[i];
          f.t += .05;
          f.t = f.t >= Math.PI * 2 ? 0 : f.t;
          f.y += f.sp;
          f.x += Math.sin(f.t * tsc) * (f.sz * .3);
          if (f.y > h + 50) f.y = -10 - Math.random() * mv;
          if (f.x > w + mv) f.x = - mv;
          if (f.x < - mv) f.x = w + mv;
          f.draw();
		  }
 	}
 	function Flake() {
 		this.draw = function() {
      	this.g = $.createRadialGradient(this.x, this.y, 0, this.x, this.y, this.sz);
			this.g.addColorStop(0, 'hsla(255,255%,255%,1)');
			this.g.addColorStop(1, 'hsla(255,255%,255%,0)');
			$.moveTo(this.x, this.y);
			$.fillStyle = this.g;
			$.beginPath();
			$.arc(this.x, this.y, this.sz, 0, Math.PI * 2, true);
			$.fill();
		}
	}
}


window.addEventListener('resize', function(){
  c.width = w = window.innerWidth;
  c.height = h = window.innerHeight;
}, false);

makeItSnow();</script>