make onTick overridable. Make delta positive always.

.github/actions/setup/action.yaml

@@ -5,7 +5,7 @@ inputs:
   flutter-version:
     description: 'The version of Flutter to use'
     required: false
-    default: '3.24.5'
+    default: '3.35.3'
   pub-cache:
     description: 'The name of the pub cache variable'
     required: false

.github/workflows/checkout.yml

@@ -66,7 +66,7 @@ jobs:
       - name: 🚂 Setup Flutter and dependencies
         uses: ./.github/actions/setup
         with:
-          flutter-version: 3.27.1
+          flutter-version: 3.35.3
 
       - name: 👷 Install Dependencies
         timeout-minutes: 1

lib/src/collisions/quadtree.dart

@@ -49,13 +49,8 @@ extension type QuadTree$QueryResult._(Float32List _bytes) {
   /// The walk stops when it iterates over all objects or
   /// when the callback returns false.
   void forEach(
-    bool Function(
-      int id,
-      double left,
-      double top,
-      double width,
-      double height,
-    ) cb,
+    bool Function(int id, double left, double top, double width, double height)
+    cb,
   ) {
     if (isEmpty) return;
     final ids = Uint32List.sublistView(_bytes);
@@ -183,14 +178,13 @@ final class QuadTree {
     required Float32List objects,
     required Uint32List recycledIds,
     required Uint32List id2node,
-  })  :
-        // Nodes
-        _nodes = nodes,
-        _recycledNodes = recycledNodes,
-        // Objects
-        _objects = objects,
-        _recycledIds = recycledIds,
-        _id2node = id2node;
+  }) : // Nodes
+       _nodes = nodes,
+       _recycledNodes = recycledNodes,
+       // Objects
+       _objects = objects,
+       _recycledIds = recycledIds,
+       _id2node = id2node;
 
   // --------------------------------------------------------------------------
   // PROPERTIES
@@ -290,10 +284,7 @@ final class QuadTree {
 
     // Get the root node of the QuadTree
     // or create a new one if it does not exist.
-    final root = _root ??= _createNode(
-      parent: null,
-      boundary: boundary,
-    );
+    final root = _root ??= _createNode(parent: null, boundary: boundary);
 
     // Create a new object in the QuadTree.
     final objectId = _getNextObjectId();
@@ -434,10 +425,7 @@ final class QuadTree {
 
     // Resize recycled ids array if needed
     if (_recycledIdsCount == _recycledIds.length)
-      _recycledIds = _resizeUint32List(
-        _recycledIds,
-        _recycledIds.length << 1,
-      );
+      _recycledIds = _resizeUint32List(_recycledIds, _recycledIds.length << 1);
     _recycledIds[_recycledIdsCount++] = objectId;
 
     return true;
@@ -452,13 +440,8 @@ final class QuadTree {
   /// The walk stops when it iterates over all objects or
   /// when the callback returns false.
   void forEach(
-    bool Function(
-      int id,
-      double left,
-      double top,
-      double width,
-      double height,
-    ) cb,
+    bool Function(int id, double left, double top, double width, double height)
+    cb,
   ) {
     final root = _root;
     if (root == null) return;
@@ -1013,7 +996,8 @@ final class QuadTree {
   // --------------------------------------------------------------------------
 
   @override
-  String toString() => 'QuadTree{'
+  String toString() =>
+      'QuadTree{'
       'nodes: $nodes, '
       'objects: $length'
       '}';
@@ -1137,13 +1121,8 @@ final class QuadTree$Node {
   /// when the callback returns false.
   @pragma('vm:prefer-inline')
   void forEach(
-    bool Function(
-      int id,
-      double left,
-      double top,
-      double width,
-      double height,
-    ) cb,
+    bool Function(int id, double left, double top, double width, double height)
+    cb,
   ) {
     if (isEmpty) return;
     if (subdivided) {
@@ -1184,12 +1163,7 @@ final class QuadTree$Node {
     final top = boundary.top;
     final nw = _northWest = tree._createNode(
           parent: this,
-          boundary: ui.Rect.fromLTWH(
-            left,
-            top,
-            halfWidth,
-            halfHeight,
-          ),
+          boundary: ui.Rect.fromLTWH(left, top, halfWidth, halfHeight),
         ),
         ne = _northEast = tree._createNode(
           parent: this,
@@ -1327,7 +1301,8 @@ final class QuadTree$Node {
       identical(this, other) || other is QuadTree$Node && id == other.id;
 
   @override
-  String toString() => r'QuadTree$Node{'
+  String toString() =>
+      r'QuadTree$Node{'
       'id: $id, '
       'objects: $length, '
       'subdivided: $_subdivided'

lib/src/repaint.dart

@@ -46,17 +46,16 @@ class RePaint extends LeafRenderObjectWidget {
     Listenable? repaint,
     bool repaintBoundary = false,
     Key? key,
-  }) =>
-      RePaintInline<T>(
-        render: render,
-        setUp: setUp,
-        update: update,
-        tearDown: tearDown,
-        frameRate: frameRate,
-        repaint: repaint,
-        repaintBoundary: repaintBoundary,
-        key: key,
-      );
+  }) => RePaintInline<T>(
+    render: render,
+    setUp: setUp,
+    update: update,
+    tearDown: tearDown,
+    frameRate: frameRate,
+    repaint: repaint,
+    repaintBoundary: repaintBoundary,
+    key: key,
+  );
 
   /// The painter controller, used to update and paint the scene.
   /// For example, a game controller or a custom painter.
@@ -76,10 +75,10 @@ class RePaint extends LeafRenderObjectWidget {
 
   @override
   RenderObject createRenderObject(BuildContext context) => RePaintBox(
-        painter: painter,
-        context: context,
-        isRepaintBoundary: repaintBoundary,
-      );
+    painter: painter,
+    context: context,
+    isRepaintBoundary: repaintBoundary,
+  );
 
   @override
   void updateRenderObject(BuildContext context, RePaintBox renderObject) {
@@ -92,7 +91,8 @@ class RePaint extends LeafRenderObjectWidget {
     renderObject._painter = painter
       ..mount(renderObject, renderObject.owner!)
       ..lifecycle(
-          WidgetsBinding.instance.lifecycleState ?? AppLifecycleState.resumed);
+        WidgetsBinding.instance.lifecycleState ?? AppLifecycleState.resumed,
+      );
   }
 }
 
@@ -136,9 +136,9 @@ class RePaintBox extends RenderBox with WidgetsBindingObserver {
     required RePainter painter,
     required BuildContext context,
     required bool isRepaintBoundary,
-  })  : _painter = painter,
-        _context = context,
-        _$isRepaintBoundary = isRepaintBoundary;
+  }) : _painter = painter,
+       _context = context,
+       _$isRepaintBoundary = isRepaintBoundary;
 
   /// Current controller.
   RePainter get painter => _painter;
@@ -185,19 +185,17 @@ class RePaintBox extends RenderBox with WidgetsBindingObserver {
     _painter
       ..mount(this, owner)
       ..lifecycle(
-          WidgetsBinding.instance.lifecycleState ?? AppLifecycleState.resumed);
+        WidgetsBinding.instance.lifecycleState ?? AppLifecycleState.resumed,
+      );
     WidgetsBinding.instance.addObserver(this);
-    _ticker = Ticker(_onTick, debugLabel: 'RePaintBox')..start();
+    _ticker = Ticker(onTick, debugLabel: 'RePaintBox')..start();
   }
 
   @override
   bool hitTestSelf(Offset position) => true;
 
   @override
-  bool hitTestChildren(
-    BoxHitTestResult result, {
-    required Offset position,
-  }) =>
+  bool hitTestChildren(BoxHitTestResult result, {required Offset position}) =>
       false;
 
   @override
@@ -250,10 +248,13 @@ class RePaintBox extends RenderBox with WidgetsBindingObserver {
   Duration _lastFrameTime = Duration.zero;
 
   /// This method is periodically invoked by the [_ticker].
-  void _onTick(Duration elapsed) {
+  void onTick(Duration elapsed) {
     if (!attached) return;
+    // Delta can be negative when widget is paused.
+    // Sometimes even like "-15" seconds.
     final delta = elapsed - _lastFrameTime;
-    final deltaMs = delta.inMicroseconds / Duration.microsecondsPerMillisecond;
+    final deltaMs =
+        delta.inMicroseconds.abs() / Duration.microsecondsPerMillisecond;
     _lastFrameTime = elapsed;
     // Update game scene and prepare for rendering.
     _painter.update(this, elapsed, deltaMs);

pubspec.yaml

@@ -36,8 +36,8 @@ platforms:
 #    path: example.png
 
 environment:
-  sdk: ^3.6.0
-  flutter: ">=3.27.0"
+  sdk: ^3.8.0
+  flutter: ">=3.35.3"
 
 dependencies:
   flutter:
@@ -52,5 +52,5 @@ dev_dependencies:
   fake_async: ^1.3.0
   flutter_lints: ">=4.0.0 <6.0.0"
   benchmark_harness: ^2.3.1
-  flame: ^1.23.0
-  vector_math: ^2.1.4
+  flame: ^1.34.0
+  vector_math: ^2.2.0