hsq-pro/src/views/vent/comment/threejs/SmokePartical1.ts

export default class SmokePartical1 {
  range; // 粒子的分布半径
  center; // 粒子的分布中心
  life; // 粒子的存活时间，毫秒
  createTime; // 粒子创建时间
  updateTime; // 上次更新时间
  size; // 粒子大小
  opacityFactor; // 粒子透系数
  opacity; //粒子透明度
  scale; // 粒子缩放量
  scaleFactor; //粒子放大系数
  position; // 粒子位置
  speed; //粒子扩散速度

  constructor(range = 10, center = { x: 0, y: 0, z: 0 }) {
    this.range = range; // 粒子的分布半径
    this.center = center; // 粒子的分布中心
    this.life = 400; // 粒子的存活时间，毫秒
    this.createTime = Date.now(); // 粒子创建时间
    this.updateTime = Date.now(); // 上次更新时间
    this.size = 3; // 粒子大小

    // 粒子透明度，及系数
    this.opacityFactor = 0.8;
    this.opacity = 1 * this.opacityFactor;

    // 粒子放大量，及放大系数
    this.scaleFactor = 10.5;
    this.scale = (this.scaleFactor * (this.updateTime - this.createTime)) / this.life; // 初始1，到达生命周期时为3

    // 粒子位置
    this.position = {
      x: Math.random() * 2 * this.range + this.center.x - this.range,
      y: this.center.y,
      z: Math.random() * 2 * this.range + this.center.z - this.range,
    };

    // 水平方向的扩散
    let speedAround = Math.random() * 10;
    if (speedAround < 5) speedAround -= 5;
    if (speedAround > 5) speedAround += 1;

    // 粒子的扩散速度
    this.speed = {
      x: speedAround,
      y: -this.life * 14,
      z: speedAround,
    };
  }
  // 更新粒子
  update() {
    const now = Date.now();
    const time = now - this.updateTime;

    // 更新位置
    this.position.x += (this.speed.x * time) / 2000;
    this.position.y += (this.speed.y * time) / 2000;
    this.position.z += (this.speed.z * time) / 2000;

    // 计算粒子透明度
    this.opacity = 1 - (now - this.createTime) / this.life;
    this.opacity *= this.opacityFactor;
    if (this.opacity < 0) this.opacity = 0;

    // 计算放大量
    this.scale = this.scaleFactor * ((now - this.createTime) / this.life) + 0.01;
    if (this.scale > 0.01 + this.scaleFactor) this.scale = 0.01 + this.scaleFactor;

    // 重置更新时间
    this.updateTime = now;
  }
}