OVERTURE

A desktop build studio for the protection period of OpenDominion — plan your dominion's first 48 in-game hours (and the out-of-protection economy that follows) against a bit-exact simulation of the round-50 game.

OVERTURE pairs a deterministic Rust engine — a clean-room reimplementation of OpenDominion's per-tick rules, validated bit-for-bit against golden vectors emitted by the real game — with a Tauri desktop app. Edit your build hour by hour and watch land, resources, population, defense, and the leave-protection gate update instantly.

Unofficial. OVERTURE is a fan-made tool. It is not affiliated with or endorsed by the OpenDominion project. See NOTICE.

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What it is — and isn't

OVERTURE is the simulator and planner: you make the decisions, it tells you exactly what the game would do. It is not an auto-solver — there is no automated build optimizer in this release. It models the protection period + post-OOP economy, not the full multiplayer game.

Modeled — and golden-validated against the real game

• Per-tick production & decay, population / housing, hour-0 opening fill, employment
• Peasant & draftee growth, prestige, morale
• All building types and land types
• Explore, rezone, construct, train, daily bonuses
• Common and racial economic self-spells
• Improvements, platinum↔ore banking, draft rate
• Tech research, late-start bonuses, starvation casualties
• The leave-protection defense gate and defensive power (raw + modded, incl. temple reduction)
• Standalone combat / range calculators (engine/src/combat.rs), golden-tested

Not modeled (out of scope for this release)

• End-to-end invasion / attacker game loop
• Espionage / spy operations
• Heroes
• Wonders
• Realm / war / government and any multiplayer mechanics

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Install (prebuilt)

Download the latest build for your platform from the Releases page.

These binaries are unsigned (no paid Apple/Microsoft signing certificate), so the OS will warn you the first time you open them. This is expected — unblock once and the app opens normally thereafter:

• macOS — right-click (or Control-click) the app → Open → Open in the dialog. (Or: System Settings → Privacy & Security → "Open Anyway".)
• Windows — on the SmartScreen prompt, click More info → Run anyway.

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Build from source

Prerequisites

• Rust (stable)
• Tauri v2 system prerequisites for your OS — see https://v2.tauri.app/start/prerequisites/ (macOS: Xcode command-line tools; Windows: WebView2 + MSVC build tools; Linux: webkit2gtk etc.)
• Node.js — only to run the Tauri CLI via npx (there is no JS bundler; the frontend is hand-authored ES modules)

Run the engine's bit-exact test suite (fast, no system deps):

cargo test --manifest-path engine/Cargo.toml --tests

Run the app in development:

cd app
npx @tauri-apps/cli dev

Build a release bundle (.app / .exe / installer under app/src-tauri/target/release/bundle/):

cd app
npx @tauri-apps/cli build

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Architecture

engine/   bit-exact round-50 simulation (Rust library) — the single source of truth.
          Game data in data/ is embedded at compile time via include_dir, so the
          shipped binary needs no external files and can't be accidentally altered.
app/      Tauri v2 desktop app:
            src-tauri/src/main.rs  thin Rust adapter — calls the engine's public API only
            src/*.js               vanilla ES-module frontend (no bundler)
data/     round-50 game tables (races, techs, spells), mirrored from OpenDominion

The frontend never reaches around the engine: every number it shows comes from a simulate call into the Rust engine (or, in a browser preview without Tauri, from app/src/mock.js, which mirrors the same shapes for design work). The engine is treated as read-only — the adapter calls it, it never modifies engine logic.

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Fidelity & testing

The engine is validated bit-for-bit against golden vectors emitted by the real OpenDominion game (the oracle), checked in under engine/tests/golden/. Every mechanic has a golden vector before it's trusted. CI (.github/workflows/ci.yml) runs the engine's bit-exact suite on every change and type-checks the desktop app on macOS and Windows.

If a contribution changes engine behavior, it must keep these tests green — or add new golden vectors that justify the change.

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Updates

There is no in-app auto-updater. New versions are announced in the community Discord with a link to a GitHub release; download the new build and replace your copy.

Maintainers: cutting a release is git tag vX.Y.Z && git push origin vX.Y.Z — the release workflow builds the unsigned macOS (universal .dmg) and Windows (.exe/.msi) bundles and attaches them to a draft release for you to review and publish.

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Contributing

• The engine is the source of truth. UI and adapter code call it; they don't re-implement game math.
• Keep cargo test --manifest-path engine/Cargo.toml --tests green; add golden vectors for new mechanics.
• OVERTURE is AGPL-3.0 — contributions are accepted under the same license. If you run a modified version as a network service, the AGPL requires you to offer users its source.

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Maintainer

Built and maintained by lethal5808 — reach me on Discord (handle lethal5808); version announcements and support live in the community Discord.

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License & attribution

OVERTURE is licensed under the GNU Affero General Public License v3 — see LICENSE.

It derives from OpenDominion (also AGPL-3.0): the engine clean-room reimplements the game's round-50 rules, and data/ mirrors its round-50 tables. Full provenance and third-party-component notes are in NOTICE.