Playing in your game

Your story reaches a player through a Patterplay runtime. You build the project to one .patterc bundle, the runtime loads it, and it hands your game a flat stream of beats (a line, a narration, a choice) that you render and drive however you like.

There’s one runtime per engine, a set of four equals (JavaScript, Unity, Unreal, and Godot) rather than approximations of each other. Every one is checked against the same test suite, so the same story behaves identically everywhere, right down to the seeded random draws. All four are shipping and verified today, so your engine is a real, supported target rather than a roadmap item.

Pick your engine

Engine	Language	Get it	Guide
JavaScript / Web	TS/JS	@patterkit/runtime (npm) or a patterplay.min.js drop-in	JavaScript & web
Unity	C#	UPM package (git URL or Release tarball)	Unity
Unreal	C++ / Blueprint	UE plugin	Unreal
Godot	GDScript	Addon	Godot

All four expose the same shape. You build an engine from a bundle, open a flow, advance it one step at a time, present each step, and pass back the player’s choice. Learn that shape once on the play loop page and the per-engine guides are mostly install notes and the local idiom.

If you would rather feel it before you read, open the interactive tour (examples/projects/tour.patter) in Patterpad and Play from Start. It shows choices, selectors, properties, conditions, and closed captions live.

What every runtime gives you

The play loop is the same everywhere. You advance a flow, receive line, text, gameEvent, choice, and end steps, and pick options. The play loop walks through it once for all four engines, and The Engine API is the deep reference for the JavaScript one.

Properties are open to the host. You read and write the story’s @patter and @scene state, and you supply your game’s own @world values.

Host navigation sends a running flow to any address when the game decides where the story goes, or plays an address in one call for barks and one-liners.

Game Data and tags arrive on every step, your typed cues merged with their defaults and ready to drive audio, animation, and quests. Save/load & Game Data covers reading them, and covers save and load, which is one call each way. The whole run (position, state, visit counts, even the PRNG) serialises to a string and restores later.

Localisation works in both modes. Read resolved text in Embedded mode, or take ids in IDs-only mode and feed them to your own system, and switch language live either way.

Closed captions are a runtime toggle. Players can turn off the non-spoken cues inside dialogue, and the runtime strips them while the line still fires so the audio plays.

Audio stays yours. Patter doesn’t play audio. Every line carries a stable id you tie voice-over to, your way. An optional resolver maps a beat to its winning take if you use Audio Folders, and you still play it.

A live state inspector ships with every engine. Watch and edit a running engine’s @patter properties while you playtest, with type-aware editors and reset-to-default. It’s an editor window in Unity and Unreal, an in-game panel in Godot, and a drop-in DOM panel on the web. Like the debug link, it’s a dev tool that stays out of shipping builds.

Live refresh & debug is a localhost link to Patterpad. Saving in the editor pushes the new bundle into the running game without a restart (JavaScript today), and the game streams its cursor back for the editor to follow like a debugger. Every engine ships a client, and each is a dev-only tool that stays inert in a shipping build.

Structure introspection walks the authored tree (scenes, blocks, snippets, beats) without playing, for editor and dev tooling. getOutline() returns the nested tree, and getBeatSequence() the flat, document-ordered beats.

The guarantee

Every Patterplay runtime passes the same shared test suite, a fixed set of cases covering expressions, full playthroughs, save/load round-trips, Game Data resolution, and locale fallback. Each case is checked on every engine and on every release. That is what lets you write the story once and trust it everywhere.