fix: Clone input vector before projecting it (#1255)

* Clone input vector before flipping * Add test for projectVector
flame-engine · Dec 20, 2021 · d1d6ad4 · d1d6ad4
1 parent 4f0fb2d
commit d1d6ad4
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diff --git a/packages/flame_forge2d/lib/forge2d_camera.dart b/packages/flame_forge2d/lib/forge2d_camera.dart
@@ -10,7 +10,7 @@ class Forge2DCamera extends Camera {
 
  @override
  Vector2 projectVector(Vector2 worldCoordinates) {
- return ((worldCoordinates..y *= -1) - position)..scale(zoom);
+ return ((worldCoordinates.clone()..y *= -1) - position)..scale(zoom);
  }
 
  @override

diff --git a/packages/flame_forge2d/test/position_test.dart b/packages/flame_forge2d/test/position_test.dart
@@ -15,4 +15,14 @@ void main() {
  });
  },
  );
+ group(
+ 'Test input vector does not get modified while function call',
+ () {
+ test('Camera should not modify the input vector while projecting it', () {
+ final vec = Vector2(5, 6);
+ TestGame().camera.projectVector(vec);
+ expect(vec, Vector2(5, 6));
+ });
+ },
+ );
 }