@polygonjs/polygonjs/dist/src/core/wfc/WFCTileConfigSampler.js

node-based WebGL 3D engine https://polygonjs.com

"use strict";
import { arrayCopy } from "../ArrayUtils";
import { randFloat } from "../math/_Module";
export class WFCTileConfigSampler {
  constructor() {
    this._cumulativeWeights = [];
    this._totalWeight = 0;
    this._tileConfigs = [];
  }
  setItemsAndWeights(tileConfigs, weights) {
    if (tileConfigs.length !== weights.length) {
      throw new Error("there must be as many weights as tileConfigs");
    }
    this._cumulativeWeights.length = 0;
    this._totalWeight = 0;
    for (const weight of weights) {
      this._totalWeight += weight;
      this._cumulativeWeights.push(this._totalWeight);
    }
    arrayCopy(tileConfigs, this._tileConfigs);
  }
  sample(seed) {
    const randomWeight = randFloat(seed) * this._totalWeight;
    let index = 0;
    while (randomWeight >= this._cumulativeWeights[index]) {
      index++;
    }
    return this._tileConfigs[index];
  }
}