Three.js流星划过效果[粒子系统]

// 引入Three.js库
import * as THREE from 'three';
 
// 定义场景、摄像机和渲染器
const scene = new THREE.Scene();
const camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 0.1, 1000);
const renderer = new THREE.WebGLRenderer();
renderer.setSize(window.innerWidth, window.innerHeight);
document.body.appendChild(renderer.domElement);
 
// 创建流星划过的粒子系统
const maxParticles = 200; // 最大粒子数量
const particleGeometry = new THREE.Geometry(); // 粒子几何体
const particleMaterial = new THREE.PointsMaterial({
    color: 0xFFFFFF,
    size: 1,
    transparent: true,
    blending: THREE.AdditiveBlending,
    depthWrite: false
});
 
// 初始化粒子位置和速度
for (let i = 0; i < maxParticles; i++) {
    const particle = new THREE.Vector3(
        Math.random() * 2 - 1,
        Math.random() * 2 - 1,
        Math.random() * 2 - 1
    );
    particle.speed = Math.random() * 0.01 + 0.005;
    particleGeometry.vertices.push(particle);
}
 
const particleSystem = new THREE.Points(particleGeometry, particleMaterial);
scene.add(particleSystem);
 
// 渲染循环
function animate() {
    requestAnimationFrame(animate);
 
    // 更新粒子位置
    for (let i = 0; i < maxParticles; i++) {
        const particle = particleGeometry.vertices[i];
        particle.multiplyScalar(1 - particle.speed);
        particle.z += particle.speed;
 
        if (particle.z > 1) {
            particle.z = -1;
            particle.x = Math.random() * 2 - 1;
            particle.y = Math.random() * 2 - 1;
        }
    }
 
    particleGeometry.verticesNeedUpdate = true;
    renderer.render(scene, camera);
}
 
animate();

这段代码创建了一个简单的粒子系统，用于模拟流星划过的效果。它定义了最大粒子数量、粒子材质和几何体，并在渲染循环中更新了粒子的位置和速度，实现了流星划过的视觉效果。