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

One category, one package, one directory. A file keeps the category in its own name anyway — [category].[name].go inside inc/[category]/ — because the prefix is what makes a file findable in a list of editor tabs, a grep, or a diff, where the directory has already fallen off.

• The category is always singular: item, scene, background, character, tape, dialog, script, world, widget, theme.
• [category].manager.go is the file that ties a package together — its entity type, its Manager, and whatever else the category shares.
• Every other file in a package holds exactly one entity: one scene, one background, one item. The file registers it itself, in an init().
• Two files have no category. inc/constants.go is the vocabulary every package imports, and inc/boot/boot.go builds the game.

main.go                                  flags + inkwell.Run
inc/constants.go                         entity names and world-state keys
inc/boot/boot.go                         New(Opts) builds the game
inc/theme/theme.manager.go               the Theme alias, its Manager, RGB/RGBA
inc/theme/theme.realworld.go             realworld-93
inc/theme/theme.nokia_punk.go            nokia-punk
inc/world/world.manager.go               unsaved runtime state
inc/world/world.action.go                custom actions
inc/tape/tape.manager.go                 the Tape entity and the lookups over it
inc/tape/tape.*.go                       one tape per file
inc/widget/widget.manager.go             the Widget alias, HUD layout, the conditions
inc/widget/widget.*.go                   one widget per file, registering itself
inc/background/background.*.go           one image asset per scene
inc/character/character.*.go             the cast, tapes included
inc/item/item.*.go                       inventory
inc/dialog/dialog.*.go                   dialogue trees
inc/script/script.*.go                   named action sequences
inc/scene/scene.manager.go               the Scene alias, its Manager, the floor
inc/scene/scene.selector.go              the map screen: pins derived from the graph
inc/scene/scene.*.go                     one file per scene

inc is constants and nothing else, so every package can import it and it can import none of them. That is also why New sits in inc/boot rather than in inc: a package cannot be imported by what it imports, and the assembly is the one thing that has to name every package at once.

Managers

Every category that owns a collection of entities has a manager, and they are all the engine's own inkwell.Manager[T] — the same registry type the *Game hangs its content off. The game defines no registry of its own.

Each one is declared in its own package's manager file, beside the alias it holds, and it needs no prefix because the package already is one:

// inc/character/character.manager.go
package character

type Character = inkwell.Character

var Manager = inkwell.NewManager[Character]()

Read from inc/boot the nine of them still line up as a list — background.Manager, character.Manager, dialog.Manager, item.Manager, scene.Manager, script.Manager, tape.Manager, theme.Manager, widget.Manager — only now the list is a consequence of the imports rather than a block someone has to keep in step.

Aliases of engine structs already carry GetName() and satisfy inkwell.Named, which is the whole of what a manager asks of them.

The methods the game uses are Register, Set, Get, All and Each. Register panics on a duplicate name — a second registration is a construction-time bug, not an update — so rewriting an entity that is already in the registry goes through Set, which keeps its position in the order. All and Each both hand back the entities in registration order.

Nearly 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.

Tape is the exception, and it is a real one: a tape is a cassette that speaks, a thing inkwell has no notion of. It names the character whose voice it is, the item that carries it and the dialogue it plays, and tape.manager.go holds the four lookups over the registry — tape.Is, tape.Of, tape.IsItem, tape.Dialogue. What a tape sounds like is not in it: the display name and the log-only voice are Character.Label and Character.Voice, because those are facts about a speaker, not about a cassette.

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 background

func init() {
	Manager.Register(Background{
		Name: inc.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, whatever file each sits in, so a package's Manager exists by the time its first entity 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.

An init() only runs if something imports the package. inc/boot names eight of the nine for their Manager, which is import enough; tape is the one nobody names, so it is there as a blank import. That list is per package, not per entity — a new scene file still touches nothing but itself.

Widgets name their layer instead of their order

A widget is a file like any other entity — widget.<name>.go, one widget, registering itself in an init() — and that includes the engine's own widgets, which the game registers as literals the same way it registers a background:

func init() {
	Manager.Register(&inkwell.Cursor{
		Name: "cursor",
	})
}

What a widget cannot take from alphabetical registration is its place in the stack: the frame has to be drawn under the slots that sit on it, the cursor over everything, and the use-with guard has to see a click after the HUD has had it. So a widget declares a layer rather than inheriting one from the order it was registered in — inkwell.LayerScene, LayerPanel, LayerHUD, LayerSpeech, LayerDialog, LayerMenu, LayerCurtain, LayerCursor. The engine draws from the bottom layer up and ticks from the top layer down, and registration order only decides ties inside one layer:

func (h *hudFrame) Layer() inkwell.Layer { return inkwell.LayerPanel }

A widget that says nothing sits on LayerHUD; ours all say it, because the layer is the one thing about a widget the file cannot show.

The other thing a widget declares is when it is there at all. The HUD is hidden for a cutscene, and that is a condition over game state, not a wrapper and not an if at the top of every Draw:

Manager.Register(&inkwell.StatusLine{
	Name: "status",
	When: whenPlaying,
	Y:    statusY,
})

whenPlaying, whenCutscene and whenUnpaused are in widget.manager.go, and they read inc.VarMode and inc.VarNote out of the engine's own State. A widget of ours says the same thing with a method — VisibleWhen() inkwell.Condition — because it has no literal to put a field in. A widget that is switched off neither ticks nor draws nor blocks a click, so nothing else has to ask.

Handing a category to the engine

Nothing is copied. inkwell.NewGame builds its own empty managers, and New hands ours over in their place — the types are identical, so the engine and the game end up sharing one registry per category rather than two in step:

g.AssetManager = background.Manager
g.CharacterManager = character.Manager
g.DialogueManager = dialog.Manager
g.ItemManager = item.Manager
g.SceneManager = scene.Manager
g.ScriptManager = script.Manager
g.WidgetManager = widget.Manager
theme.Manager.Each(g.ThemeManager.Register)

Themes are the odd one out and stay a copy: NewGame puts four preset themes into its ThemeManager, and replacing it would throw them away. Ours are added to that set instead.

One consequence of not copying: a manager swapped in this way must be in place before inkwell.Run, which is where the engine wires up the parts that hold a registry directly. fillSelectorPins runs before the hand-off for the same reason — it writes the derived pins back into SceneManager with Set.

The defaults a scene leaves out are no longer written into it at all. g.Player names the character a scene with no actors of its own gets, placed at his Start; g.Walkboxes is the floor a scene walks on when it declares none. Both are fields on the *Game, so a scene file that says nothing about either is saying "the usual", and the selector opts out by declaring both empty.

What runs at boot

New names two scripts and nothing else — the opening a player sees is content like every other script, in script/script.opening.go, not a slice built in the wiring:

g.StartAt(start)
g.OnStart(inc.ScriptOpening)
if o.Finale {
	g.OnFinale(inc.ScriptFinale)
}

OnFinale is the engine's hook for a closing script, queued straight after the opening. Here it is what -finale uses to drop into the ending, which is why it is set from Opts rather than always.

The rest of New is fields on the *Game, and every one of them replaces something this package used to carry itself:

g.WindowScale = 2
g.Player = inc.Paul
g.Walkboxes = scene.Floor
g.UseWithFail = script.UseWithFail

UseWithFail is the response to a use-with pair nobody authored — the engine asks for it the same way it asks for ExitLook and ExitTake, and the lines live with the rest of the writing, in script/script.usewith_fail.go.

The world

There is exactly one game, so there is exactly one world — and since there is exactly one, the package is the singleton. There is no World value to pass around and no back-reference for a widget to hold: world.Do(…), world.Slot2(), world.SetPending(…) are reachable from anywhere that imports world. New calls world.Attach(g), which binds the engine and resets the run state, so building the game twice is clean.

world holds as little as it can get away with. The mode and the top bar's note are State vars (inc.VarMode, inc.VarNote), because state the engine can see is state a Condition can read — that is what makes a widget's When possible and what puts "— paused" in the top bar without anyone pushing it there. world.Do hands its action to g.Do, the engine's queue, so the game runs one action at a time without a pump of its own. What is left in package variables is the two things the engine has no notion of: the tape waiting to speak, and the cassette on its way into slot 2. Only world.Attach resets them.

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

Naming

The package is the namespace now, so an identifier never repeats what the package already says. It is scene.Floor, not scene.SceneFloor; tape.Dialogue, not tape.TapeDialogue; widget.Manager, not widget.WidgetManager; world.Do, not world.WorldDo. Read the call site, not the declaration, when choosing a name:

scene.FillSelectorPins()   tape.Is(speaker)   world.Do(a)   widget.ScreenW

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: boot.New and boot.Opts, the constants in inc/constants.go, each package's Manager and entity type, the colour tokens, the tape lookups (tape.Is, tape.Of, tape.IsItem, tape.Dialogue), the world (world.Do, world.Slot2, …) and the action constructors (world.Paused, world.SetMode, world.UseTheme, world.TapeOffer, world.Fn). A tape's line is inkwell.Say like anyone else's — the tape voice is on the character, not on a second spelling of Say.

Everything else stays unexported, and now the compiler holds the line: the HUD widgets (tapeSlots, letterbox, hudFrame, …), the conditions (whenPlaying, whenCutscene, whenUnpaused), the runners, setMode, setNote, setVarIfEmpty.

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

The layering is the import graph, so the compiler keeps it:

inc ← theme ← world ← tape ← widget ← boot ← main
        ↑        ↑                      ↑
        └── content ───────────────────-┘

inc imports nothing and everything imports it. world knows nothing about the HUD or the content; both build on it, never the other way round — and an arrow pointing back is now an import cycle, not a review comment. The one edge worth knowing is widget → tape: the tape slots ask which cassette a tape is in, so the tape concept sits below the HUD rather than beside it.

Adding a scene

1. Constants in inc/constants.go: Scene<Name>, Bg<Name>
2. inc/scene/scene.<name>.go — an init() registering a Scene
3. inc/background/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.

The engine next door

inkwell is checked out beside this repository, and so is the wiki that documents it. Paths are relative to the game's root:

../../engines/inkwell                                           the engine source
../../services/wiki-pages/pages/engines/inkwell/default.en.md   the manual, English
../../services/wiki-pages/pages/engines/inkwell/default.hu.md   the manual, Hungarian

The engine's module path is git.teletypegames.org/engines/inkwell and go.mod pins a pseudo-version of it, so a local edit is invisible here until it is pushed:

git -C ../../engines/inkwell commit … && git -C ../../engines/inkwell push
go get git.teletypegames.org/engines/inkwell@master

A replace directive is fine while trying something out, but it never survives into a commit — drop it and bump the pin instead.

Three things move together when the engine changes: the code, README.md in the inkwell checkout, and both wiki pages. The two pages are a translation pair, section for section — an edit to one is an edit to the other. The no-comment rule stops at the module boundary: inkwell's own source is commented, and edits there follow its style, not this one's.

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.