@woosh/meep-engine/src/core/process/task/util/randomCountTask.js

Pure JavaScript game engine. Fully featured and production ready.

import { array_shuffle } from "../../../collection/array/array_shuffle.js";
import { seededRandom } from "../../../math/random/seededRandom.js";
import Task from "../Task.js";
import { TaskSignal } from "../TaskSignal.js";

/**
 *
 * @param {number} seed RNG seed
 * @param {number|function(*):number} initial
 * @param {number|function(*):number} limit
 * @param {function(index:int)} callback
 * @returns {Task}
 */
export function randomCountTask(seed, initial, limit, callback) {

    const random = seededRandom(seed);

    const span = limit - initial;

    const sequence = new Uint16Array(span);

    let i = 0;

    function cycle() {
        if (i >= span) {
            return TaskSignal.EndSuccess;
        }

        const order = sequence[i];

        const index = order + initial;

        callback(index);

        i++;

        return TaskSignal.Continue;
    }

    return new Task({
        name: `Count ${initial} -> ${limit}`,
        initializer() {

            i = 0;

            //generate sequence
            for (let i = 0; i < span; i++) {
                sequence[i] = i;
            }

            //shuffle
            array_shuffle(random, sequence);
        },
        cycleFunction: cycle,
        computeProgress: function () {

            if (span === 0) {
                return 0;
            }

            return i / span;
        }
    });
}