mky-vent-base/src/views/vent/comment/threejs/SmokePartical.ts

// 定义Partical类
import * as THREE from 'three';
import gsap from 'gsap';

export default class SmokePartical {
  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 = 0; //粒子透明度
  scale = 0; // 粒子缩放量
  scaleFactor; //粒子放大系数
  position; // 粒子位置
  speed; //粒子扩散速度
  normal; // 粒子法向
  pathArr = []; // 运动路径对象，包含路径、是否扩散等信息
  pathLifeRatio: number[] = [];
  updateFactor = 5;
  pathIndex = 0;
  isDie = false;
  currentPathAlpha = 0; // 当前路段的插值因素

  // 动画更新系数;

  constructor(range = 10, center = { x: 0, y: 0, z: 0 }, opacityFactor, scaleFactor, life, pathArr?) {
    this.range = range;
    this.center = center;
    this.life = life;
    this.createTime = Date.now();
    this.updateTime = Date.now();
    this.size = 15;

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

    // 粒子放大量，及放大系数
    this.scaleFactor = scaleFactor;

    this.position = {
      x: 0,
      y: 0,
      z: 0,
    };

    this.initDistance(pathArr);
  }
  initDistance(pathArr) {
    let totalLen = 0;
    const pathLen: number[] = [];
    for (let i = 0; i < pathArr.length; i++) {
      const obj = {
        path0: pathArr[i].path0.clone(),
        path1: pathArr[i].path1.clone(),
        isSpread: pathArr[i].isSpread,
        spreadDirection: pathArr[i].spreadDirection, // 1是由小变大，-1是由大变小
        spreadRang: pathArr[i]['spreadRang'] || 0,
      };
      if (obj.isSpread) {
        if (obj.spreadDirection >= 1) {
          let vec;
          if (Math.abs(obj.path0.y - obj.path1.y) > 3) {
            const len = obj.spreadRang ? obj.spreadRang : 8;
            vec = new THREE.Vector3(
              (Math.random() * 2 - 1) * 3 + obj.path1.x,
              Math.random() * len + obj.path1.y,
              (Math.random() * 2 - 1) * 3 + obj.path1.z
            );
          } else {
            vec = new THREE.Vector3(
              (Math.random() * 2 - 1) * 3 + obj.path1.x,
              (Math.random() * 2 - 1) * 3 + obj.path1.y,
              (Math.random() * 2 - 1) * 3 + obj.path1.z
            );
          }
          obj.path1.copy(vec);
        } else if (obj.spreadDirection == -1) {
          let vec;
          if (Math.abs(obj.path0.y - obj.path1.y) > 3) {
            vec = new THREE.Vector3(
              (Math.random() * 2 - 1) * 3 + obj.path0.x,
              Math.random() * 8 + obj.path0.y,
              (Math.random() * 2 - 1) * 3 + obj.path0.z
            );
          } else {
            vec = new THREE.Vector3(
              (Math.random() * 2 - 1) * 3 + obj.path0.x,
              (Math.random() * 2 - 1) * 3 + obj.path0.y,
              (Math.random() * 2 - 1) * 3 + obj.path0.z
            );
          }
          obj.path0.copy(vec);
        }
      } else if (obj.spreadDirection != 0) {
        const len = 1;
        const vec = new THREE.Vector3(
          (Math.random() * 2 - 1) * 3 * len + obj.path0.x,
          (Math.random() * 2 - 1) * obj.spreadDirection * len + obj.path0.y,
          (Math.random() * 2 - 1) * 3 * len + obj.path0.z
        );
        const vec1 = new THREE.Vector3(
          (Math.random() * 2 - 1) * 3 * len + obj.path1.x,
          (Math.random() * 2 - 1) * obj.spreadDirection * len + obj.path1.y,
          (Math.random() * 2 - 1) * 3 * len + obj.path1.z
        );
        obj.path0.copy(vec);
        obj.path1.copy(vec1);
      }
      this.pathArr.push(obj);
      const len = obj.path0.distanceTo(obj.path1);
      pathLen.push(len);
      totalLen += len;
    }

    pathLen.forEach((len) => {
      this.pathLifeRatio.push(len / totalLen);
    });
  }

  // 更新粒子
  update() {
    if (!this.pathArr || this.pathArr.length - 1 < this.pathIndex) {
      this.isDie = true;
      return;
    }
    let isFirst = false;
    if (this.currentPathAlpha == 0) {
      isFirst = true;
    }

    const pathArr = this.pathArr[this.pathIndex];
    const position = new THREE.Vector3(this.position.x, this.position.y, this.position.z);
    const life = this.pathLifeRatio[this.pathIndex] * this.life;
    this.currentPathAlpha += 1 / life;
    const currentPathAlpha = this.currentPathAlpha > 1 ? 1 : this.currentPathAlpha;
    position.lerpVectors(pathArr.path0, pathArr.path1, currentPathAlpha);

    if (position != undefined) {
      // 更新位置
      this.position.x = position.x;
      this.position.y = position.y;
      this.position.z = position.z;

      if (!pathArr.isSpread) {
        if (isFirst) this.opacity = this.opacityFactor * 0.5;
        if (isFirst) this.scale = ((0.3 * Math.random() + 0.7) / 2) * this.scaleFactor;
      } else {
        if (pathArr.spreadDirection == 1) {
          // 计算粒子透明度
          this.opacity = 1 - currentPathAlpha;
          this.opacity *= this.opacityFactor * 0.5;
          if (this.opacity < 0) this.opacity = 0;

          // 计算放大量
          this.scale = this.scaleFactor * (currentPathAlpha + 1 / 2);
          // if (this.scale > 1 + this.scaleFactor) this.scale = 1.5 * this.scaleFactor;
        } else {
          // 计算粒子透明度
          this.opacity = currentPathAlpha * currentPathAlpha * currentPathAlpha;
          // this.opacity = this.currentPathAlpha;
          this.opacity *= this.opacityFactor * 0.5;
          if (this.opacity < 0) this.opacity = 0;

          // 计算放大量
          this.scale = this.scaleFactor * (1 - currentPathAlpha + 1 / 2);
        }
      }

      if (this.currentPathAlpha >= 1) {
        ++this.pathIndex;
        this.currentPathAlpha = 0;
      }
    }
  }

  controlUpdate() {
    // gsap.to(this.speed, {
    //   x: 250,
    //   duration: 1,
    //   ease: 'none',
    //   repeat: -1,
    // });
  }
}