@rpgm-tools/neo-angband-core

The headless game engine behind Neo Angband, a faithful but moddable port of Angband, meant to be playable almost anywhere.

No renderer, no input, no DOM, no filesystem: rules, world, entities, effects, generation and the save format, as plain modules. Runs in Node and in a browser.

npm install @rpgm-tools/neo-angband-core

Use cases

There are two main audiences:

• Writing a Neo Angband mod. A mod's plugin receives the running engine as ctx.core, so it never imports this package at runtime, but it wants the types, and its tests want a real engine to run against. That is what this package is for.
• Building something else on Angband's rules. A bot, a solver, a simulator, a different front end. The engine is headless on purpose and this is a supported use.

Quick start

import { Rng, ENGINE_VERSION, PARITY_BASELINE } from "@rpgm-tools/neo-angband-core";

// The RNG is upstream's WELL1024a, seeded exactly as Rand_state_init does,
// so a seed reproduces a sequence across runs, platforms and save/load.
const rng = new Rng(1234);
console.log(rng.damroll(3, 6), rng.damroll(3, 6), rng.damroll(3, 6)); // 9 13 8

console.log(ENGINE_VERSION, PARITY_BASELINE); // 1.22.0 4.2.6

Two entry points:

| Import | What it holds | | --- | --- | | @rpgm-tools/neo-angband-core | The engine: rules, world, entities, effects, generation, saves | | @rpgm-tools/neo-angband-core/host | The HostIo seam: the shape of z-file.c, for a front end that gives the engine real file and terminal I/O |

The API is upstream's, deliberately

Neo Angband is an exact-parity port: the engine reproduces Angband 4.2.6's behaviour, including its warts, and it is verified against the C rather than against taste. Two consequences for anyone importing this package:

• Names follow the C. damroll, mBonus, caveKnown, takeHit, objectDesc. If you know angband/src, you already know your way around; if you expect a designed-from-scratch API, this is not one.
• Bugs are reproduced, not fixed. Upstream's faults are in here on purpose, with tests pinning them. Fixes live in a separate mod (neo-angband-mod-bug-fixes), never in the engine.

Game data is a separate concern. This package is the rules; Angband's gamedata (monsters, objects, dungeon profiles) is compiled into a content pack that the host loads. So @rpgm-tools/neo-angband-core on its own can roll dice, run the effect interpreter and read a save, but it cannot generate a populated level without content handed to it.

Versioning

Standard Semantic Versioning as of 1.0.0, the game's public release: a breaking API change is a MAJOR bump, a backward-compatible feature is MINOR, and a fix is PATCH. 0.x was the pre-release line, where the API could change inside a MINOR bump. PARITY_BASELINE is the upstream release the port is verified against and moves independently of ENGINE_VERSION.

Licence

Neo Angband keeps Angband's dual licence, as the Angband project asks of its variants: GNU GPL v2, or the Angband licence, at your option. npm can only carry one SPDX identifier, so the manifest says GPL-2.0-only, the more restrictive of the two. The full text of both, and what it means for the bundled art, is in LICENSE.md.

Angband is the work of Ben Harrison, James E. Wilson, Robert A. Koeneke and the Angband contributors. The port is by neostryder / RPGM Tools.