使用 Three.js 创建随机粒子效果，使用 Simplex 4D 噪声实现粒子运动，结合 ShaderMaterial 实现自定义着色器。

float snoise(vec4 v){
    const vec2  C = vec2( 0.138196601125010504,  // (5 - sqrt(5))/20  G4
                          0.309016994374947451); // (sqrt(5) - 1)/4   F4
    // First corner
    vec4 i  = floor(v + dot(v, C.yyyy) );
    vec4 x0 = v -   i + dot(i, C.xxxx);
    
    // Other corners
    vec4 i0;
    vec3 isX = step( x0.yzw, x0.xxx );
    vec3 isYZ = step( x0.zww, x0.yyz );
    i0.x = isX.x + isX.y + isX.z;
    i0.yzw = 1.0 - isX;
    i0.y += isYZ.x + isYZ.y;
    i0.zw += 1.0 - isYZ.xy;
    i0.z += isYZ.z;
    i0.w += 1.0 - isYZ.z;
    
    // ... 更多噪声计算代码
}

class Particles extends THREE.Points {
    constructor(gu) {
        let particlePos = [];
        let particleAlpha = [];
        let g = new THREE.BufferGeometry()
            .setFromPoints(
                new Array(1000).fill().map((_) => {
                    particlePos.push(
                        Math.random() * 0.2 + 0.2,
                        Math.random() + 1,
                        Math.random(),
                        0
                    );
                    particleAlpha.push(
                        Math.random(),
                        Math.random() * 0.4 + 0.1,
                        0,
                        0
                    );

                    let r = 5;
                    return new THREE.Vector3().setFromCylindricalCoords(
                        Math.sqrt(r * r * Math.random()),
                        Math.random() * Math.PI * 2,
                        Math.random() * 10
                    );
                })
            )
            .setAttribute("particlePos", new THREE.Float32BufferAttribute(particlePos, 4))
            .setAttribute("particleAlpha", new THREE.Float32BufferAttribute(particleAlpha, 4));
        
        let m = new THREE.PointsMaterial({
            size: 0.5,
            transparent: true,
            opacity: 0.8,
            blending: THREE.AdditiveBlending,
            onBeforeCompile: (shader) => {
                shader.uniforms.time = gu.time;
                shader.vertexShader = noise + shader.vertexShader;
                // ... 更多着色器修改
            }
        });
        
        super(g, m);
    }
}