@animech-public/playcanvas/build/playcanvas.dbg/src/core/object-pool.js

PlayCanvas WebGL game engine

/**
 * A pool of reusable objects of the same type. Designed to promote reuse of objects to reduce
 * garbage collection.
 *
 * @ignore
 */
class ObjectPool {
  /**
   * @param {new (...args: any[]) => any} constructorFunc - The constructor function for the
   * objects in the pool.
   * @param {number} size - The initial number of object instances to allocate.
   */
  constructor(constructorFunc, size) {
    /**
     * The constructor function for the objects in the pool.
     *
     * @type {new (...args: any[]) => any}
     * @private
     */
    this._constructor = void 0;
    /**
     * Array of object instances.
     *
     * @type {object[]}
     * @private
     */
    this._pool = [];
    /**
     * The number of object instances that are currently allocated.
     *
     * @type {number}
     * @private
     */
    this._count = 0;
    this._constructor = constructorFunc;
    this._resize(size);
  }

  /**
   * @param {number} size - The number of object instances to allocate.
   * @private
   */
  _resize(size) {
    if (size > this._pool.length) {
      for (let i = this._pool.length; i < size; i++) {
        this._pool[i] = new this._constructor();
      }
    }
  }

  /**
   * Returns an object instance from the pool. If no instances are available, the pool will be
   * doubled in size and a new instance will be returned.
   *
   * @returns {object} An object instance from the pool.
   */
  allocate() {
    if (this._count >= this._pool.length) {
      this._resize(this._pool.length * 2);
    }
    return this._pool[this._count++];
  }

  /**
   * All object instances in the pool will be available again. The pool itself will not be
   * resized.
   */
  freeAll() {
    this._count = 0;
  }
}

export { ObjectPool };