jay/Splashy-gba_emulator

public

Initial commit: SplashyGBA emulator core and Flutter app4da97ba12 days ago156 lines · 4.4 KB

1	import 'dart:async';
2	import 'dart:isolate';
3	import 'dart:ui' as ui;
4
5	import 'package:flutter/foundation.dart';
6	import 'package:gba_core/gba_core.dart';
7
8	import 'emulator_worker.dart';
9
10	/// A running game, seen from the UI: the emulator itself runs in its own
11	/// isolate so that the UI stays smooth.
12	///
13	/// Frames arrive as [ui.Image]s in [frame]
14	/// in between are dropped rather than queued.
15	final class EmulatorSession {
16	EmulatorSession._(this._isolate
17
18	final Isolate _isolate;
19	final ReceivePort _fromWorker;
20	SendPort? _commands;
21
22	/// The latest frame, 240×160.
23	final ValueNotifier<ui.Image
24
25	/// Frames per second the emulator is managing (about 59.7 at full speed).
26	final ValueNotifier<double
27
28	/// The game's title, once it has loaded.
29	String title = '';
30
31	/// The game's save type, once it has loaded.
32	SaveType saveType = SaveType.
33
34	/// Whether the built-in BIOS stand-in is in use.
35	bool usesHleBios = true;
36
37	/// An error the emulator reported, if any.
38	final ValueNotifier<String
39
40	final Completer<void
41	Uint8List? _pendingPixels;
42	bool _decoding = false;
43	bool _disposed = false;
44
45	/// Starts the game at [romPath]. Completes once it is running, or throws
46	/// a [StateError] with a message for the user if it cannot start.
47	static Future<EmulatorSession
48	required String romPath,
49	required String savePath,
50	String? biosPath,
51	}) async {
52	final fromWorker = ReceivePort()
53	final ready = Completer<
54	final isolate = await Isolate
55	emulatorWorkerMain,
56	WorkerConfig(
57	toUi: fromWorker.sendPort,
58	romPath: romPath,
59	savePath: savePath,
60	biosPath: biosPath,
61	),
62	debugName: 'emulator',
63	errorsAreFatal: true,
64	onExit: fromWorker.sendPort,
65	);
66	final session = EmulatorSession.
67	fromWorker.listen((message) => session._onMessage
68	await ready.future;
69	final startError = session.error.
70	if (session._commands == null) {
71	throw StateError(startError ?? 'The emulator stopped while starting.'
72	}
73	return session;
74	}
75
76	/// Sets the held buttons: a mask of [GbaKey] bits.
77	void setKeys(int
78
79	void pause() => _commands
80
81	void resume() => _commands
82
83	/// Stops the game, waiting until its save has been stored.
84	Future<void> stop
85	_commands?.send(WorkerCommand.
86	await _stopped.future.timeout(
87	const Duration(seconds:
88	onTimeout: _isolate.kill,
89	);
90	_dispose();
91	}
92
93	void _onMessage(Object
94	switch (message) {
95	case (
96	commands: final SendPort commands
97	title: final String title
98	saveType: final SaveType saveType
99	usesHleBios: final bool usesHleBios
100	):
101	_commands = commands;
102	this.title = title;
103	this.saveType = saveType;
104	this.usesHleBios = usesHleBios;
105	if (!ready.isCompleted) ready.complete
106	case (pixels: final TransferableTypedData
107	this.fps.value = fps
108	_showFrame(pixels.materialize().
109	case (error: final String
110	this.error.value = error
111	case stoppedMessage \|\| null:
112	// null: the isolate exited (onExit).
113	if (!ready.isCompleted) ready.complete
114	if (!_stopped.isCompleted) _stopped.complete
115	_fromWorker.close();
116	}
117	}
118
119	void _showFrame(Uint8List
120	if (_decoding) {
121	_pendingPixels = pixels; // Keep only the newest.
122	return;
123	}
124	_decoding = true;
125	ui.decodeImageFromPixels(
126	pixels,
127	Ppu.width,
128	Ppu.height,
129	ui.PixelFormat.rgba8888,
130	(image) {
131	_decoding = false;
132	if (_disposed) {
133	image.dispose();
134	return;
135	}
136	final previous = frame.value;
137	frame.value = image;
138	previous?.dispose();
139	final pending = _pendingPixels;
140	if (pending != null) {
141	_pendingPixels = null;
142	_showFrame(pending);
143	}
144	},
145	);
146	}
147
148	void _dispose() {
149	if (_disposed) return;
150	_disposed = true;
151	frame.value?.dispose();
152	frame.dispose();
153	fps.dispose();
154	error.dispose();
155	}
156	}