potree-sdk/src/objects/fireParticle/explode/Tween.js

import * as THREE from "../../../../libs/three.js/build/three.module.js";
class Tween {

    constructor(times, values) {
      this.times = times || []
      this.values = values || []
    }
  
    lerp(t) {
      if(this.times.length == 0) return
      let i = 0, n = this.times.length
      while(i < n && t > this.times[i]) i++
      if(i == 0) return this.values[0]
      if(i == n) return this.values[n-1]
      const ratio = (t - this.times[i-1]) / (this.times[i] - this.times[i-1])
      if(this.values[0] instanceof THREE.Vector3) {
        return this.values[i-1].clone().lerp(this.values[i], ratio)
      } else {
        return this.values[i-1] + ratio * (this.values[i] - this.values[i-1])
      }
      
    }
  
  }
  
  export default Tween