ref: use pauseEngine and resumeEngine

flame-engine · Aug 24, 2023 · a6652a5 · a6652a5
1 parent d12799f
commit a6652a5
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Showing 3 changed files with 36 additions and 120 deletions.
diff --git a/packages/flame/lib/src/game/game.dart b/packages/flame/lib/src/game/game.dart
@@ -35,14 +35,6 @@ abstract mixin class Game {
   late final GestureDetectorBuilder gestureDetectors =
       GestureDetectorBuilder(refreshWidget)..initializeGestures(this);
 
-  /// The game's lifecycle state.
-  ///
-  /// This is used to discard the first [update] call after the app was in the
-  /// background to avoid a massive `dt` value.
-  ///
-  /// See [GameLifecycleState] for more details.
-  GameLifecycleState gameLifecycleState = GameLifecycleState.foregrounded;
-
   /// This should update the state of the game.
   void update(double dt);
 
@@ -145,27 +137,9 @@ abstract mixin class Game {
   /// This is the lifecycle state change hook; every time the game is resumed,
   /// paused or suspended, this is called.
   ///
-  /// You may wish to use [gameLifecycleState] instead of [state]
-  /// to use more game-specific lifecycle states.
-  ///
-  /// Check [AppLifecycleState] and [GameLifecycleState]
-  /// for details about the events received.
-  @mustCallSuper
+  /// The default implementation does nothing; override to use the hook.
+  /// Check [AppLifecycleState] for details about the events received.
   void lifecycleStateChange(AppLifecycleState state) {
-    switch (state) {
-      case (AppLifecycleState.resumed || AppLifecycleState.inactive)
-          when gameLifecycleState == GameLifecycleState.backgrounded:
-        // We are coming back from background.
-        gameLifecycleState = GameLifecycleState.foregrounding;
-        break;
-      case (AppLifecycleState.paused || AppLifecycleState.detached)
-          when gameLifecycleState != GameLifecycleState.backgrounded:
-        // We are going to background.
-        gameLifecycleState = GameLifecycleState.backgrounded;
-        break;
-      default:
-        break;
-    }
   }
 
   /// Method to perform late initialization of the [Game] class.
@@ -390,19 +364,3 @@ abstract mixin class Game {
     gameStateListeners.forEach((callback) => callback());
   }
 }
-
-enum GameLifecycleState {
-  /// The game is backgrounded.
-  ///
-  /// This corresponds to [AppLifecycleState.paused] and [AppLifecycleState.detached].
-  backgrounded,
-
-  /// The game has been foregrounded but the first update should be
-  /// disregarded if `pauseWhenBackgrounded` is true.
-  foregrounding,
-
-  /// The game is foregrounded.
-  ///
-  /// This corresponds to [AppLifecycleState.resumed] and [AppLifecycleState.inactive].
-  foregrounded,
-}
diff --git a/packages/flame_forge2d/lib/forge2d_game.dart b/packages/flame_forge2d/lib/forge2d_game.dart
@@ -29,13 +29,10 @@ class Forge2DGame extends FlameGame {
   /// 
   /// Defaults to false.
   bool pauseWhenBackgrounded;
+  bool _pausedBecauseBackgrounded = false;
 
   @override
   void update(double dt) {
-    if (!shouldUpdate()) {
-      return;
-    }
-
     super.update(dt);
     world.stepDt(dt);
   }
@@ -52,19 +49,32 @@ class Forge2DGame extends FlameGame {
     return screenToWorld(position)..y *= -1;
   }
 
-  @protected
-  bool shouldUpdate() {
-    switch (gameLifecycleState) {
-      case GameLifecycleState.backgrounded:
-        // Don't update when backgrounded
-        return !pauseWhenBackgrounded;
-      case GameLifecycleState.foregrounding:
-        // Discard the first `update` call after the app was in the background
-        // to avoid a massive [dt] value.
-        gameLifecycleState = GameLifecycleState.foregrounded;
-        return !pauseWhenBackgrounded;
-      case GameLifecycleState.foregrounded:
-        return true;
+  @override
+  @mustCallSuper
+  void lifecycleStateChange(AppLifecycleState state) {
+    switch (state) {
+      case AppLifecycleState.resumed:
+      case AppLifecycleState.inactive:
+        if (_pausedBecauseBackgrounded) {
+          resumeEngine();
+        }
+      case AppLifecycleState.paused:
+      case AppLifecycleState.detached:
+      case AppLifecycleState.hidden:
+        if (pauseWhenBackgrounded) {
+          pauseEngine();
+          _pausedBecauseBackgrounded = true;
+        }
     }
   }
+  @override
+  void pauseEngine() {
+    _pausedBecauseBackgrounded = false;
+    super.pauseEngine();
+  }
+  @override
+  void resumeEngine() {
+    _pausedBecauseBackgrounded = false;
+    super.resumeEngine();
+  }
 }
diff --git a/packages/flame_forge2d/test/forge2d_game_test.dart b/packages/flame_forge2d/test/forge2d_game_test.dart
@@ -1,5 +1,5 @@
-import 'package:flame/components.dart';
-import 'package:flame/game.dart';
+import 'dart:ui' show AppLifecycleState;
+
 import 'package:flame_forge2d/flame_forge2d.dart';
 import 'package:test/test.dart';
 
@@ -10,17 +10,6 @@ class _TestForge2dGame extends Forge2DGame {
   }
 }
 
-class _TestComponent extends Component {
-  _TestComponent({
-    required this.onUpdate,
-  });
-
-  final void Function() onUpdate;
-
-  @override
-  void update(double dt) => onUpdate.call();
-}
-
 void main() {
   group(
     'Test corresponding position on screen and in the Forge2D world',
@@ -69,54 +58,13 @@ void main() {
 
   group('Game lifecycle state:', () {
     test('update should only be called if foregrounded', () async {
-      var updateCalled = false;
-      void onUpdate() => updateCalled = true;
-
       final game = _TestForge2dGame();
-      final component = _TestComponent(onUpdate: onUpdate);
-      await game.add(component);
-      const dt = 1 / 60;
-
-      await game.onLoad();
-
-      game.gameLifecycleState = GameLifecycleState.backgrounded;
-      game.update(dt);
-      expect(
-        updateCalled,
-        false,
-        reason: 'Update should not run when app is backgrounded',
-      );
-      expect(
-        game.gameLifecycleState,
-        GameLifecycleState.backgrounded,
-        reason: 'Game should still be backgrounded',
-      );
-
-      game.gameLifecycleState = GameLifecycleState.foregrounding;
-      game.update(dt);
-      expect(
-        updateCalled,
-        false,
-        reason: 'Update should not run on first foregrounded update',
-      );
-      expect(
-        game.gameLifecycleState,
-        GameLifecycleState.foregrounded,
-        reason: 'Game should be foregrounded',
-      );
 
-      game.gameLifecycleState = GameLifecycleState.foregrounded;
-      game.update(dt);
-      expect(
-        updateCalled,
-        true,
-        reason: 'Update should run when app is foregrounded',
-      );
-      expect(
-        game.gameLifecycleState,
-        GameLifecycleState.foregrounded,
-        reason: 'Game should be foregrounded',
-      );
+      game.lifecycleStateChange(AppLifecycleState.paused);
+      expect(game.paused, true);
+
+      game.lifecycleStateChange(AppLifecycleState.resumed);
+      expect(game.paused, false);
     });
   });
 }