realworld/CLAUDE.md

Real World

A point & click adventure built on the inkwell engine (Ebitengine).

Conventions

No comments

Go source files carry no comments. Not doc comments, not inline comments, not section headers. If a piece of code needs explaining, rename it or restructure it until it does not, and put the reasoning in README.md instead.

The single exception is compiler directives (//go:embed, //go:build), which are instructions to the toolchain rather than prose.

English only

Everything written in the repository is in English: identifiers, string literals, commit messages, README.md, this file. The design wiki is in Hungarian; when a concept crosses over, translate it and keep the mapping one-to-one.

No tests

Do not write tests and do not add test files. Correctness is checked by running the game.

Struct literals are always multi-line

Every field of a struct instance goes on its own line, with a trailing comma — never on the same line as the brace, never two fields on one line.

return inkwell.Asset{
	Name: BgStreet,
	Path: "assets/bg/street.png",
	Kind: inkwell.AssetImage,
}

Not inkwell.Asset{Name: BgStreet, Path: "...", Kind: inkwell.AssetImage}.

This holds for nested literals too, including small ones such as inkwell.Point. Slice and map literals are not covered by the rule.

Layout

All game code lives in one flat package, inc. There are no subdirectories: a file's name carries the structure, in the form [category].[name].go.

• The category is always singular: item, scene, background, character, dialog, script, world, ui, theme, names, boot, content.
• [category].manager.go is the file that ties a category together — its manager, its entity type, whatever the category shares.
• Every other file in a category holds exactly one entity: one scene, one background, one item. The file registers it itself, in an init().

main.go                    flags + inkwell.Run
inc/manager.manager.go     Manager[T]: the generic registry every category uses
inc/manager.interface.go   ManagerInterface and the compile-time assertions
inc/boot.manager.go        wiring; New(Opts) builds the game
inc/names.manager.go       entity names and world-state keys
inc/theme.manager.go       the theme manager and the colour helpers
inc/theme.realworld.go     realworld-93
inc/theme.nokia_punk.go    nokia-punk
inc/world.manager.go       unsaved runtime state
inc/world.action.go        custom actions and the action pump
inc/ui.manager.go          HUD layout and widget registration
inc/ui.*.go                custom widgets, coloured text
inc/content.manager.go     composition root; calls every register…
inc/background.*.go        one image asset per scene
inc/character.*.go         the cast, tapes included
inc/item.*.go              inventory
inc/dialog.*.go            dialogue trees
inc/script.*.go            named action sequences
inc/scene.manager.go       the Scene alias, the defaults every scene gets
inc/scene.selector.go      the map screen: its pins are derived from the graph
inc/scene.*.go             one file per scene

manager is the one category with no entities of its own: it holds the registry every other category is built from.

Managers

Every category that owns a collection of entities has a manager, and they are all the same generic type — Manager[T] in manager.manager.go. It keeps one slice in registration order and one map[string]int beside it, so GetByName is a map lookup, not a scan.

Since the entity types are aliases of engine structs, no method can be attached to them; the manager is told how to read a name instead, which is all it needs:

type Character = inkwell.Character

var CharacterManager = NewManager(func(entity Character) string { return entity.Name })

That is the whole of a category's manager file — an alias and one line. There are seven managers: BackgroundManager, CharacterManager, DialogManager, ItemManager, ScriptManager, SceneManager, ThemeManager.

manager.interface.go holds the contract they all keep, and asserts each one against it. A new manager goes on that list.

type ManagerInterface[T any] interface {
	Register(entity T)
	GetByName(name string) (T, bool)
	GetAll() []T
}

Register replaces by name and keeps the entity's position, so registering twice is an update, never a duplicate. GetAll returns the slice itself, in registration order.

Every entity type is an alias, Scene included. It was once a struct of our own, because inkwell's Scene could not carry exits; that gap was closed in the engine, so there is nothing left for a second type to hold.

Entities register themselves

An entity file is a literal and nothing else. No constructor function, no list somewhere else to keep in step — the file hands itself to its manager in an init():

package inc

func init() {
	BackgroundManager.Register(Background{
		Name: BgServerFarm,
		Path: "assets/bg/server_farm.png",
		Kind: inkwell.AssetImage,
	})
}

Adding an entity is adding a file. Deleting one is deleting a file. Package-level variables are initialised before any init() runs, so the managers exist by the time the first file registers into one.

init() order is file-name order, so registration order is alphabetical. Nothing may depend on it — including the order the arrow keys walk the scenes, which is simply the order the files sit in.

Handing a category to the engine

Once the game exists, registerAll walks a manager and gives every entity to the engine's own manager. registerContent is the whole of it:

func registerContent() {
	registerAll(BackgroundManager, World.G.AssetManager.Register)
	registerAll(CharacterManager, World.G.CharacterManager.Register)
	registerAll(ItemManager, World.G.ItemManager.Register)
	registerAll(DialogManager, World.G.DialogueManager.Register)
	registerAll(ScriptManager, World.G.ScriptManager.Register)
	registerScene()
}

registerScene is the one that needs its own function: it fills in the defaults a scene may leave out (Paul's starting position, the floor walkbox), and it derives the selector's pins by reading the exit graph backwards.

The world

There is exactly one game, so there is exactly one world: World, a package-level singleton in world.manager.go. Nothing takes a *world parameter and no widget holds a back-reference — World.Do(…), World.HUDVisible(), World.Slot2() are reachable from anywhere in the package. New calls World.attach(g), which binds the engine and resets the runtime state, so building the game twice is clean.

This is what lets an entity file be a literal: the tape-insert script closes over World, not over a parameter it would have had to be handed.

Naming

One package means one namespace, so an entity's constructor carries its category as a prefix:

sceneFloor  sceneDefaults  registerScene  fillSelectorPins

Entities themselves need no name at all — they are anonymous literals inside their file's init(), and the file name says which one it is.

Exported names are the authoring vocabulary — what a content file spells out: New and Opts, World, the managers and the entity types they hold, the constants in names.manager.go, the colour tokens, and the action constructors (TapeSay, Paused, SetMode, EnterScene, Back, Fn).

Everything else is machinery and stays unexported: the HUD widgets (tapeSlots, letterbox, hudFrame, …), the register… functions, the runners, sceneDefaults, fillSelectorPins.

The word is scene, the engine's own. The wiki and the concept-art deck count screens, and this code used to as well, but everything a screen had that a scene did not now lives in inkwell. "Screen" survives only where it means the display: ScreenW, ScreenH.

Layering

Nothing is enforced by the compiler any more, so the layering is a rule kept by hand:

names ← theme ← world ← ui
                  ↑      ↑
               content ──┴── boot ← main

world knows nothing about the HUD or the content. Both build on it, never the other way round.

Adding a scene

1. Constants in inc/names.manager.go: Scene<Name>, Bg<Name>
2. inc/scene.<name>.go — an init() registering a Scene
3. inc/background.<name>.go — an init() registering a Background
4. A 640×380 PNG in assets/bg/

Nothing else moves. There is no list to update.

Commands

make build     native binary into bin/
make wasm      js/wasm build into dist/
make watch     rebuild on change
go run . -scene <name>     start on a given scene
go run . -finale           start with the finale

Art is embedded into the binary (//go:embed assets in main.go), because js/wasm has no OS filesystem and make binaries ships the executable alone.

The screen is 640×380 because the engine stretches a background over the whole window: any other size squashes the paintings.