CSS+Canvas绘制最美星空(一闪一闪亮晶晶效果+流星划过)

1.效果

在这里插入图片描述

2.代码

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <style>
    body,
    html {
      margin: 0;
      padding: 0;
      overflow: hidden;
    }

    body {
      background: #000;
    }

    canvas {
      width: 100%;
      height: 100vh;
      display: block;
    }
  </style>
  <title>星空</title>
</head>

<body>
  <canvas id="canvas"></canvas>

  <script>
    const canvas = document.getElementById('canvas');
    const ctx = canvas.getContext('2d');
    canvas.width = window.innerWidth;
    canvas.height = window.innerHeight;

    class Star {
      constructor(x, y, brightness, type) {
        this.x = x;
        this.y = y;
        this.brightness = brightness;
        this.alpha = 1;
        this.fade = Math.random() * 0.05 + 0.01;
        this.type = type;
        this.size = (type === 'cross') ? 2 : 1; // 根据类型设置大小
      }

      draw() {
        ctx.beginPath();
        if (this.type === 'cross') {
          ctx.strokeStyle = `rgba(255, 255, 255, ${this.alpha})`;
          ctx.lineWidth = 1; // 设置线条粗细
          ctx.moveTo(this.x, this.y - 1 * this.size);
          ctx.lineTo(this.x, this.y + 1 * this.size);
          ctx.moveTo(this.x - 1 * this.size, this.y);
          ctx.lineTo(this.x + 1 * this.size, this.y);
          ctx.stroke();
        } else {
          ctx.fillStyle = `rgba(255, 255, 255, ${this.alpha})`;
          ctx.arc(this.x, this.y, this.size, 0, Math.PI * 2);
          ctx.fill();
        }
      }

      update() {
        this.brightness += Math.random() * 0.1 - 0.05;
        this.brightness = Math.min(Math.max(this.brightness, 0), 1);

        this.alpha += this.fade;
        if (this.alpha > 1 || this.alpha < 0) {
          this.fade = -this.fade;
        }
      }
    }

    let stars = [];
    const numStars = 200;

    function createStars() {
      for (let i = 0; i < numStars; i++) {
        let type = Math.random() > 0.5 ? 'cross' : 'particle';
        stars.push(new Star(
          Math.random() * canvas.width,
          Math.random() * canvas.height,
          Math.random(),
          type
        ));
      }
    }

    function animateStars() {
      ctx.clearRect(0, 0, canvas.width, canvas.height);
      for (let i = 0; i < stars.length; i++) {
        stars[i].update();
        stars[i].draw();
      }
      requestAnimationFrame(animateStars);
    }

    let shootingStar = null;

    function createShootingStar() {
      const startX = Math.random() * canvas.width * 0.5; // 从左侧开始
      const startY = 0; // 从顶部开始
      const speed = 4 + Math.random() * 6;
      const angle = Math.PI / 6 + Math.random() * Math.PI / 3; // 修改划过的角度范围

      // 增加长度、宽度和颜色属性
      shootingStar = { x: startX, y: startY, speed, angle, length: 80 + Math.random() * 40, thickness: 1 + Math.random() * 2, color: 'rgba(255, 255, 255, 1)' };
    }

    function animateShootingStar() {
      if (!shootingStar) {
        if (Math.random() < 0.01) {
          createShootingStar();
        }
      } else {
        const { x, y, speed, angle, length, thickness, color } = shootingStar;
        ctx.save();
        ctx.translate(x, y);
        ctx.rotate(angle);

        const gradient = ctx.createLinearGradient(0, 0, length, 0);
        gradient.addColorStop(0, color);
        gradient.addColorStop(1, 'rgba(255, 255, 255, 0)');

        ctx.strokeStyle = gradient;
        ctx.lineWidth = thickness;
        ctx.beginPath();
        ctx.moveTo(0, 0);
        ctx.lineTo(length, 0);
        ctx.stroke();

        ctx.restore();

        shootingStar.x += speed * Math.cos(angle);
        shootingStar.y += speed * Math.sin(angle);

        if (shootingStar.x > canvas.width || shootingStar.y > canvas.height) {
          shootingStar = null;
        }
      }
      requestAnimationFrame(animateShootingStar);
    }

    createStars();
    animateStars();
    animateShootingStar();
  </script>
</body>

</html>