The Aethelgard Engine — a browser RPG engine that ships as plain files.

// the module contract — every logic file looks like this

/* js/graphics.js — sprite packs and image rendering */
"use strict";
(function () {
  const G = window.Game;

  /* the whole game draws its art through this one call */
  G.sprite = function (key, fallback) {
    const s = G.SPRITES[key];
    return s && s.src ? img(s) : fallback;  // emoji if no pack
  };

  G.registerGraphicsPack = function (pack) {
    G.GRAPHICS_PACKS[pack.id] = pack;      // a mod calls this
  };
})();

A graphics pack is just a mod that registers sprites for the engine's sprite keys — enemy.<id>, class.<id>, item.<id>, loc.<id> and so on.

1. Clone and serve

   No install step. Any static host works — a tiny local server is enough to get the service worker and PWA install.

   # extract/clone the whole folder first
   git clone https://github.com/drsamonline/aethelgard-rpg-engine.git
   cd Aethelgard-Engine
   python3 -m http.server 8080
   # → http://localhost:8080

2. Run the checks

   Plain Node and Python — there is nothing to install. CI runs the syntax check, JSON validation and the three suites on every push.

   node --check js/core.js
   node test6.js && node test7.js && node test8.js
   node tools/verify.js        # end-to-end
   node tools/sims.js 1 12     # 12 simulations
   node js/validate.js         # content validator
   python3 tools/static-audit.py .

3. Extend it

   Add content to js/data/, or drop a mod into mods/ and change nothing in the core.

   window.AETHELGARD_MODS =
     window.AETHELGARD_MODS || [];
   
   window.AETHELGARD_MODS.push({
     id: "my-mod", name: "My Mod",
     version: "1.0.0", author: "You",
     impact: "additive"   // additive | story | overhaul
   });