playcanvas/build/playcanvas.dbg/src/scene/gsplat-unified/gsplat-budget-balancer.js

Open-source WebGL/WebGPU 3D engine for the web

var __defProp = Object.defineProperty;
var __defNormalProp = (obj, key, value) => key in obj ? __defProp(obj, key, { enumerable: true, configurable: true, writable: true, value }) : obj[key] = value;
var __publicField = (obj, key, value) => __defNormalProp(obj, typeof key !== "symbol" ? key + "" : key, value);
import { NUM_BUCKETS } from "./constants.js";
class GSplatBudgetBalancer {
  constructor() {
    /**
     * Buckets storing NodeInfo references.
     * @type {Array<Array>|null}
     * @private
     */
    __publicField(this, "_buckets", null);
  }
  /**
   * Initialize bucket infrastructure on first use.
   * @private
   */
  _initBuckets() {
    if (!this._buckets) {
      this._buckets = new Array(NUM_BUCKETS);
      for (let i = 0; i < NUM_BUCKETS; i++) {
        this._buckets[i] = [];
      }
    }
  }
  /**
   * Balances splat budget across all octree instances by adjusting LOD levels.
   * Uses sqrt-based bucket distribution to give more precision to nearby geometry.
   * Makes multiple passes, adjusting by one LOD level per pass, until budget is reached
   * or all nodes hit their respective limits (per-instance rangeMin or rangeMax).
   *
   * @param {Map<GSplatPlacement, GSplatOctreeInstance>} octreeInstances - Map of
   * GSplatOctreeInstance objects.
   * @param {number} budget - Target splat budget for octrees.
   */
  balance(octreeInstances, budget) {
    this._initBuckets();
    for (let i = 0; i < NUM_BUCKETS; i++) {
      this._buckets[i].length = 0;
    }
    let totalOptimalSplats = 0;
    for (const [, inst] of octreeInstances) {
      const nodes = inst.octree.nodes;
      const nodeInfos = inst.nodeInfos;
      for (let nodeIndex = 0, len = nodes.length; nodeIndex < len; nodeIndex++) {
        const nodeInfo = nodeInfos[nodeIndex];
        const optimalLod = nodeInfo.optimalLod;
        if (optimalLod < 0) continue;
        const lods = nodes[nodeIndex].lods;
        nodeInfo.lods = lods;
        this._buckets[nodeInfo.budgetBucket].push(nodeInfo);
        totalOptimalSplats += lods[optimalLod].count;
      }
    }
    let currentSplats = totalOptimalSplats;
    if (currentSplats === budget) {
      return;
    }
    const isOverBudget = currentSplats > budget;
    let done = false;
    while (!done && (isOverBudget ? currentSplats > budget : currentSplats < budget)) {
      let modified = false;
      if (isOverBudget) {
        for (let b = NUM_BUCKETS - 1; b >= 0 && !done; b--) {
          const bucket = this._buckets[b];
          for (let i = 0, len = bucket.length; i < len; i++) {
            const nodeInfo = bucket[i];
            if (nodeInfo.optimalLod < nodeInfo.inst.rangeMax) {
              const lods = nodeInfo.lods;
              const optimalLod = nodeInfo.optimalLod;
              currentSplats -= lods[optimalLod].count - lods[optimalLod + 1].count;
              nodeInfo.optimalLod = optimalLod + 1;
              modified = true;
              if (currentSplats <= budget) {
                done = true;
                break;
              }
            }
          }
        }
      } else {
        for (let b = 0; b < NUM_BUCKETS && !done; b++) {
          const bucket = this._buckets[b];
          for (let i = 0, len = bucket.length; i < len; i++) {
            const nodeInfo = bucket[i];
            if (nodeInfo.optimalLod > nodeInfo.inst.rangeMin) {
              const lods = nodeInfo.lods;
              const optimalLod = nodeInfo.optimalLod;
              const splatsAdded = lods[optimalLod - 1].count - lods[optimalLod].count;
              if (currentSplats + splatsAdded <= budget) {
                nodeInfo.optimalLod = optimalLod - 1;
                currentSplats += splatsAdded;
                modified = true;
                if (currentSplats >= budget) {
                  done = true;
                  break;
                }
              } else {
                done = true;
                break;
              }
            }
          }
        }
      }
      if (!modified) {
        break;
      }
    }
  }
}
export {
  GSplatBudgetBalancer
};