From 1085518fe279e674bef9a7b938d59926472511f3 Mon Sep 17 00:00:00 2001
From: Lukas Klingsbo <me@lukas.fyi>
Date: Thu, 4 Jan 2024 22:56:07 +0100
Subject: [PATCH] fix: Consider displaced hitboxes in GestureHitboxes mixin
 (#2957)

Previously the point sent in to `containsLocalPoint` for
`GestureHitboxes` didn't take the parent transformation into
consideration, this is fixed in this PR.
---
 .../components/mixins/gesture_hitboxes.dart   |  8 +++-
 .../src/components/position_component.dart    |  6 ++-
 .../mixins/gesture_hitboxes_test.dart         | 43 +++++++++++++++++++
 3 files changed, 54 insertions(+), 3 deletions(-)

diff --git a/packages/flame/lib/src/components/mixins/gesture_hitboxes.dart b/packages/flame/lib/src/components/mixins/gesture_hitboxes.dart
index 19cebaf38d9..f7ebc60447d 100644
--- a/packages/flame/lib/src/components/mixins/gesture_hitboxes.dart
+++ b/packages/flame/lib/src/components/mixins/gesture_hitboxes.dart
@@ -19,8 +19,14 @@ mixin GestureHitboxes on Component {
     return hitboxes.any((hitbox) => hitbox.containsPoint(point));
   }
 
+  static final _temporaryPoint = Vector2.zero();
+
   @override
   bool containsLocalPoint(Vector2 point) {
-    return hitboxes.any((hitbox) => hitbox.containsLocalPoint(point));
+    return hitboxes.any(
+      (hitbox) => hitbox.containsLocalPoint(
+        hitbox.parentToLocal(point, output: _temporaryPoint),
+      ),
+    );
   }
 }
diff --git a/packages/flame/lib/src/components/position_component.dart b/packages/flame/lib/src/components/position_component.dart
index 2237d9ae224..8a8498b53dd 100644
--- a/packages/flame/lib/src/components/position_component.dart
+++ b/packages/flame/lib/src/components/position_component.dart
@@ -273,10 +273,12 @@ class PositionComponent extends Component
   }
 
   @override
-  Vector2 parentToLocal(Vector2 point) => transform.globalToLocal(point);
+  Vector2 parentToLocal(Vector2 point, {Vector2? output}) =>
+      transform.globalToLocal(point, output: output);
 
   @override
-  Vector2 localToParent(Vector2 point) => transform.localToGlobal(point);
+  Vector2 localToParent(Vector2 point, {Vector2? output}) =>
+      transform.localToGlobal(point, output: output);
 
   /// Convert local coordinates of a point [point] inside the component
   /// into the parent's coordinate space.
diff --git a/packages/flame/test/components/mixins/gesture_hitboxes_test.dart b/packages/flame/test/components/mixins/gesture_hitboxes_test.dart
index 680b1c137d7..f72fcee032d 100644
--- a/packages/flame/test/components/mixins/gesture_hitboxes_test.dart
+++ b/packages/flame/test/components/mixins/gesture_hitboxes_test.dart
@@ -47,6 +47,49 @@ void main() {
       expect(component.containsPoint(point), isTrue);
     });
 
+    testWithFlameGame('CircleHitbox is displaced within the parent component',
+        (game) async {
+      final component = _HitboxComponent();
+      component.position.setAll(10);
+      component.size.setValues(2.0, 2.0);
+
+      final hitbox = CircleHitbox(
+        position: Vector2(1.0, 1.5),
+        radius: 0.5,
+        anchor: Anchor.center,
+      );
+
+      component.add(hitbox);
+      await game.ensureAdd(component);
+
+      final point = component.position + hitbox.position;
+      expect(component.containsPoint(point), isTrue);
+      final outsidePoint = component.position + Vector2(1.0, 0.99);
+      expect(component.containsPoint(outsidePoint), isFalse);
+    });
+
+    testWithFlameGame(
+        'RectangleHitbox is displaced within the parent component',
+        (game) async {
+      final component = _HitboxComponent();
+      component.position.setAll(10);
+      component.size.setValues(2.0, 2.0);
+
+      final hitbox = RectangleHitbox(
+        position: Vector2(1.0, 1.5),
+        size: Vector2.all(1.0),
+        anchor: Anchor.center,
+      );
+
+      component.add(hitbox);
+      await game.ensureAdd(component);
+
+      final point = component.position + hitbox.position;
+      expect(component.containsPoint(point), isTrue);
+      final outsidePoint = component.position + Vector2(1.0, 0.99);
+      expect(component.containsPoint(outsidePoint), isFalse);
+    });
+
     testWithFlameGame('get component hitboxes', (game) async {
       final component = _HitboxComponent();
       component.position.setValues(1.0, 1.0);