`ludic build` produces a program. Double-clicked it opens a Terminal window, it wears the generic executable icon, it calls itself whatever the file is called, and it carries none of its assets. `ludic bundle` produces an application. Everything it needs is in package.ludic, so the command takes no arguments: an Info.plist and PkgInfo from `app` lines, an .icns built by sips and iconutil at all ten sizes macOS asks for from a single source PNG, the asset pack in Contents/Resources, and an ad-hoc signature - which is not optional on Apple silicon, where an unsigned binary is killed rather than warned about. The bundle identifier falls back to the package path reversed, so a project that never thinks about it still gets a defensible one instead of two apps sharing a key Launch Services hangs the Dock, saved state and permissions off. A bundled game is moved to ~/Library/Application Support/<name> before main, because Finder starts a .app with its working directory at "/" where no save could ever be written. Reads come out of the pack, writes land somewhere real and per-user, and the game's save code needs no change and no platform knowledge. The splash is the other half of looking like an application. A game that loads 165 MB spends a visible moment doing it with nothing on screen, which from the outside is indistinguishable from a launch that failed. splash_show puts a borderless window up from the same constructor that mounts the pack - before main, so it appears while the process is still starting rather than after the slow part it exists to cover - and reads the artwork out of the pack like any other asset. It turns the run loop enough times to be mapped and composited there and then; once composited the backing store survives a busy main thread, so it stays up for the whole load. Nothing hides it automatically. Only the game knows when its first real frame is ready, and a splash that vanishes before that leaves the same black gap it was covering, so the game calls App.splash_hide(). Headless there is no splash and the call lowers to nothing. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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Shipping a Ludic game
ludic build gives you a program. ludic bundle gives you an application.
The difference matters more than it sounds. A built binary opens its assets by a path relative to the working directory, so it runs from the project root and nowhere else; double-clicked it opens a Terminal window; it wears the generic executable icon and calls itself whatever the file is called. None of that is something you can hand to a player.
ludic pack # every asset into one file
ludic bundle # ...and that, the binary, an icon and the metadata, as a .app
What goes in the manifest
Everything the bundler needs lives in package.ludic, so the command takes no
arguments:
package "git.workshopsoft.io/workshopsoft/maroon-lake"
version "0.1.0"
app name "Maroon Lake"
app id "io.workshopsoft.maroon-lake"
app icon "assets/app/icon.png"
app splash "assets/app/splash.png"
app splash_bg "#0d1b2a"
app category "public.app-category.adventure-games"
app copyright "(c) 2026 Workshopsoft"
app min_macos "11.0"
pack "assets"
| key | what it does | default |
|---|---|---|
app name |
the name under the icon, spaces and all | the package's name |
app id |
the bundle identifier | derived from the package path |
app version |
CFBundleVersion |
the manifest's version |
app icon |
a source PNG, ideally 1024x1024 | no icon |
app splash |
shown from process start until the game says otherwise | no splash |
app splash_bg |
#RRGGBB painted behind the splash |
black |
app category |
LSApplicationCategoryType |
omitted |
app copyright |
NSHumanReadableCopyright |
omitted |
app min_macos |
LSMinimumSystemVersion |
11.0 |
app sign |
a codesigning identity | ad-hoc (-) |
app out |
where to write the bundle | build/<name>.app |
pack |
an asset root, repeatable | assets/ if it exists |
Only app name is worth setting deliberately. The identifier is derived from the
package path when you omit it - git.workshopsoft.io/workshopsoft/maroon-lake
becomes io.workshopsoft.maroon-lake - but it is worth pinning, because Launch
Services keys the Dock, saved window state and permissions off it, and two apps
sharing one identifier is a class of bug that looks like haunting.
The asset pack
ludic pack writes a .lpak: a header, an entry table sorted by name, a name
heap and the blobs. Entries are stored, not compressed - PNG, JPEG and glTF
binary arrive compressed already, and a decompressor on the load path would
spend CPU to make the file no smaller.
Nothing about how the game is written changes. This line:
let model = gltf_load("assets/kit/hiker", "hiker.gltf", "hiker")
reads a file during development and a run of bytes inside
Maroon Lake.app/Contents/Resources/game.lpak once shipped, and cannot tell
which. That works because the pack is spliced in at file_open, the one place
every asset in a Ludic program comes through - gltf_load, tex_load,
Audio.load, Fs.read_text and the renderer's own shader loads all bottom out
there. Fs.exists and Fs.size consult the packs too, so a game that guards a
load with Fs.exists keeps finding its assets once they are packed.
The pack is mmap'd rather than read, so 165 MB of terrain costs one syscall at
startup and pages in only what the game touches.
ludic pack --list build/maroon-lake.lpak # what is in it
ludic pack --verify build/maroon-lake.lpak # re-hash every entry
More than one pack
Contents/Resources/packs.index is a plain list, and the order is load-bearing:
pack base.lpak
pack patch.lpak
Packs mount in the order listed and a later one shadows an earlier one, so a patch or an add-on replaces individual files without rewriting the base pack. An override is always a pack, never a loose file: the pack is searched before the filesystem, so a stray or corrupt file cannot shadow a shipped asset.
Where a bundled game saves
A .app launched from Finder starts with its working directory at /, where
nothing is writable, so packs.index also carries:
home Maroon Lake
and the runtime moves the process to ~/Library/Application Support/Maroon Lake
before main. Reads come out of the pack; writes land somewhere real and
per-user. A game's save code needs no change and no platform knowledge.
The splash
A game that loads 165 MB spends a noticeable moment doing it, and until it is done there is nothing on screen - the window is not open yet, because opening it is part of what the game does once it has something to draw. From the outside that is indistinguishable from a launch that failed.
The splash is raised from a constructor that runs before main, so it
appears while the process is still starting rather than after the expensive
part, which is the only ordering that helps. It is a borderless window holding
the game's own artwork, read out of the pack like any other asset.
Nothing hides it automatically. Only the game knows when its first real frame is ready, so the game says so:
App.splash_hide()
During development
None of this is in the way. Without a packs.index beside the executable -
which is every ludic run - nothing mounts, no directory change happens, no
splash appears, and every open goes to the filesystem exactly as before.
Packing is a shipping step, and it is invisible until you ship.
Signing and distribution
ludic bundle ad-hoc signs the result. On Apple silicon that is not optional
the way it was on Intel: an unsigned binary is killed outright rather than
merely warned about, so without a signature the app will not run even on the
machine that built it.
An ad-hoc signature is not enough to get the app past Gatekeeper on someone else's Mac. That needs a Developer ID certificate and notarisation, which are Apple's, not Ludic's:
app sign "Developer ID Application: Your Name (TEAMID)"
ludic bundle
xcrun notarytool submit "build/Maroon Lake.app" --keychain-profile NOTARY --wait
xcrun stapler staple "build/Maroon Lake.app"
The bundle it makes
Maroon Lake.app/
Contents/
Info.plist the metadata Finder, the Dock and Launch Services read
PkgInfo the eight bytes that predate Info.plist and are still read
MacOS/Maroon Lake the game
Resources/
AppIcon.icns every size macOS asks for, from one source PNG
game.lpak every asset the game opens
packs.index what to mount, where to save, what to show at boot