js实现水波

实现水波效果的JavaScript方法

使用Canvas绘制水波效果是一种常见的实现方式。以下是一个基本的水波动画实现示例：

const canvas = document.getElementById('waveCanvas');
const ctx = canvas.getContext('2d');

let time = 0;
const waveHeight = 20;
const waveLength = 0.01;
const speed = 0.05;

function animate() {
    ctx.fillStyle = 'rgba(0, 0, 0, 0.05)';
    ctx.fillRect(0, 0, canvas.width, canvas.height);

    ctx.beginPath();
    ctx.moveTo(0, canvas.height/2);

    for(let x = 0; x < canvas.width; x++) {
        const y = waveHeight * Math.sin(x * waveLength + time) + canvas.height/2;
        ctx.lineTo(x, y);
    }

    ctx.strokeStyle = 'hsl(' + Math.abs(200 * Math.sin(time)) + ', 100%, 50%)';
    ctx.stroke();

    time += speed;
    requestAnimationFrame(animate);
}

animate();

优化水波效果

为了创建更真实的水波效果，可以结合多个波形：

function animate() {
    ctx.fillStyle = 'rgba(0, 0, 0, 0.05)';
    ctx.fillRect(0, 0, canvas.width, canvas.height);

    ctx.beginPath();
    ctx.moveTo(0, canvas.height/2);

    for(let x = 0; x < canvas.width; x++) {
        const y1 = 10 * Math.sin(x * 0.02 + time);
        const y2 = 15 * Math.sin(x * 0.015 + time * 1.2);
        const y = y1 + y2 + canvas.height/2;
        ctx.lineTo(x, y);
    }

    ctx.strokeStyle = 'rgba(100, 200, 255, 0.8)';
    ctx.stroke();

    time += 0.05;
    requestAnimationFrame(animate);
}

交互式水波效果

添加鼠标交互可以让水波效果更加生动：

let mouseX = 0;
let mouseY = 0;

canvas.addEventListener('mousemove', (e) => {
    mouseX = e.clientX;
    mouseY = e.clientY;
});

function animate() {
    ctx.fillStyle = 'rgba(0, 0, 0, 0.05)';
    ctx.fillRect(0, 0, canvas.width, canvas.height);

    ctx.beginPath();
    ctx.moveTo(0, canvas.height/2);

    for(let x = 0; x < canvas.width; x++) {
        const distanceToMouse = Math.abs(x - mouseX);
        const waveEffect = 50 * Math.exp(-distanceToMouse * 0.01);

        const y = waveHeight * Math.sin(x * waveLength + time) 
                + waveEffect * Math.sin(time * 2) 
                + canvas.height/2;
        ctx.lineTo(x, y);
    }

    ctx.strokeStyle = 'rgba(100, 200, 255, 0.8)';
    ctx.stroke();

    time += speed;
    requestAnimationFrame(animate);
}

使用WebGL实现高性能水波

对于更复杂的水波效果，可以考虑使用WebGL：

// 简单的WebGL水波着色器示例
const vertexShader = `
    attribute vec2 position;
    void main() {
        gl_Position = vec4(position, 0.0, 1.0);
    }
`;

const fragmentShader = `
    precision highp float;
    uniform float time;

    void main() {
        vec2 uv = gl_FragCoord.xy / 500.0;
        float wave = sin(uv.x * 10.0 + time) * 0.1;
        gl_FragColor = vec4(0.0, wave + 0.5, 1.0, 1.0);
    }
`;

// WebGL初始化代码...

CSS实现简单水波效果

如果不需要复杂交互，纯CSS也能实现简单水波动画：

<div class="wave"></div>

<style>
.wave {
    width: 200px;
    height: 200px;
    background: radial-gradient(
        circle at 75% 50%,
        rgba(100, 200, 255, 0.8),
        transparent 70%
    );
    border-radius: 50%;
    animation: wave 2s infinite ease-in-out;
}

@keyframes wave {
    0% { transform: scale(1); opacity: 0.8; }
    50% { transform: scale(1.2); opacity: 0.5; }
    100% { transform: scale(1); opacity: 0.8; }
}
</style>

以上方法提供了从简单到复杂的水波效果实现方案，可以根据项目需求选择合适的实现方式。Canvas方案适合需要精细控制和交互的场景，而CSS方案则更适合简单的装饰性效果。