flutter3d_editor_play

Outside the 1.0 semver promise. It carries the engine's number to say which engine it goes with, and a release of a package its signatures name may break it in a minor, labelled in its CHANGELOG (SUPPORT.md says which).

Play from a level editor. The game a level belongs to is run with flutter run --machine, reloaded, restarted and stopped from the editor, and a level saved while it runs is sent to it and taken without the game starting over.

It is what the Play button of apps/flutter3d_editor runs, and what the play tools of flutter3d_mcp/editor.dart run, so an agent's Play and a person's are the same code.

final root = projectRootOnDisk('game/assets/levels/first.json');
final run = FlutterRun(projectRoot: root!, device: 'macos');
await run.start();
run.state.changes.listen((PlayState state) => print(state));

// Later, after the code changed:
print(await run.hotSwap()); // "Reloaded 3 of 812 libraries"

// After a save:
if (run.state.value case PlayRunning(:final vmService)) {
  print(describeLevelApplied(await pushLevel(vmService, savedDocument)));
}


`FlutterRun`	One `flutter run --machine`: its state, its console, the events the game posts, reload, restart, stop
`projectRootFor`, `projectRootOnDisk`	The project a level file belongs to: the nearest `pubspec.yaml` above it
`flutterDevices`, `parseFlutterDevices`	What `-d` can be given, from `flutter devices --machine`
`pushLevel`	A saved level, sent to the running game's `ext.flutter3d.level.apply` — or, given the `base` it was saved over, as a patch to `ext.flutter3d.level.patch`, whole only when the game says the patch is stale
`Watched`	A value and a stream of its changes, where Flutter's `ValueNotifier` cannot go
`AttachedRun`	A game somebody else started, by its VM service address: console, events, hot reload and restart, detach
`PostedEvent`, `eventsSince`	What the game posted with `flutter3d_game`'s `postToolEvent` — numbered, capped like the console — and the read by cursor that `play_events` answers with
`PlayedGame`	What `FlutterRun` and `AttachedRun` both are, for one panel over either
`connectVmService`	A VM service connection over a socket a browser has too

package:flutter3d_editor_play/testing.dart has FakeFlutterTool, a flutter run --machine a test controls, and fakeFlutterRun over it; FakeGame, a VM service a test controls (posts is the game posting an event), and fakeAttachedRun over it; fakeFlutterRun(game:) finds it at the address the tool reports.

In a browser

A web build has no process to start, so it imports package:flutter3d_editor_play/attach.dart, which has no dart:io under it, and attaches to a game that is already running:

final game = AttachedRun('http://127.0.0.1:8181/abc=/'); // what the game printed
await game.start();
print(await game.hotSwap()); // "Swapped in the new code"
print(describeLevelApplied(await pushLevel(game.vmService, savedDocument)));
await game.stop(); // lets go; the game keeps running

The hot reload is not the VM's: a Flutter game cannot compile its own new code. The flutter run or flutter attach connected to it registers reloadSources and hotRestart on its VM service, and AttachedRun calls those, as DevTools does. With no tool connected it says so and what to run. Checked against a real macOS game from the Dart VM and from Chrome, on a page served from localhost.

Why a package of its own

Play starts a process and talks to it. flutter3d_editor_core is written never to do either, so a validator or a web build can open a level with it, and the editor's MCP server could not reach code that lived inside the editor application. Here both depend on it, and neither on the other. It is plain Dart with dart:io: it runs under dart run and in a desktop app, and only attach.dart of it in a browser, where there is no process to start.

The game side of it, the extension a level is sent to, is LiveLevel in flutter3d_game.

flutter3d_editor_play

In a browser

Why a package of its own

Libraries

flutter3d_editor_play package