feat: add play / editor mode

tests/core_tests.cpp

@@ -37,6 +37,20 @@ namespace {
         std::string GetTypeName() const override { return "TestComponent"; }
     };
 
+    class CountingComponent final : public Component {
+    public:
+        explicit CountingComponent(GameObject& owner) : Component(owner, "CountingComponent") {}
+
+        void Update(float) override { ++updates; }
+        void LateUpdate(float) override { ++lateUpdates; }
+        void FixedUpdate(float) override { ++fixedUpdates; }
+        std::string GetTypeName() const override { return "CountingComponent"; }
+
+        int updates{0};
+        int lateUpdates{0};
+        int fixedUpdates{0};
+    };
+
     class RemovingListener final : public EventListener {
     public:
         explicit RemovingListener(std::unique_ptr<RemovingListener>* victim)
@@ -268,6 +282,30 @@ namespace {
 
         SceneManager::GetInstance().Destroy();
     }
+
+    void testEditModeSkipsUpdates()
+    {
+        SceneManager& sceneManager = SceneManager::GetInstance();
+        Scene& scene = sceneManager.CreateScene("edit mode");
+        auto* counter = scene.CreateGameObject("counter")->AddComponent<CountingComponent>();
+
+        sceneManager.SetPlaying(false);
+        sceneManager.Update(0.1f);
+        sceneManager.FixedUpdate(0.1f);
+        sceneManager.LateUpdate(0.1f);
+        check(counter->updates == 0 && counter->fixedUpdates == 0 && counter->lateUpdates == 0,
+              "edit mode must not tick components");
+        check(scene.GetObjects().size() == 1, "edit mode must still add objects created in the editor");
+
+        sceneManager.SetPlaying(true);
+        sceneManager.Update(0.1f);
+        sceneManager.FixedUpdate(0.1f);
+        sceneManager.LateUpdate(0.1f);
+        check(counter->updates == 1 && counter->fixedUpdates == 1 && counter->lateUpdates == 1,
+              "play mode must tick components");
+
+        sceneManager.Destroy();
+    }
 }
 
 void RunCoreTests()
@@ -280,4 +318,5 @@ void RunCoreTests()
     testEngineComponentRegistration();
     testSceneCurrentCamera();
     testHierarchyMoves();
+    testEditModeSkipsUpdates();
 }

tests/serialization_tests.cpp

@@ -334,6 +334,40 @@ namespace {
 
         SceneManager::GetInstance().Destroy();
     }
+
+    void testPlayModeSnapshotRestore()
+    {
+        Scene& scene = SceneManager::GetInstance().CreateScene("snapshot");
+        GameObject* box = scene.CreateGameObject("box");
+        box->GetTransform().SetLocalPosition({1.f, 2.f, 3.f});
+        scene.CreateGameObject("other");
+        scene.CommitPendingAdditions();
+        scene.SetSelectedObject(box->GetId());
+
+        auto snapshot = SceneSerializer::Capture(scene);
+        check(snapshot.has_value(), "a scene must be capturable without a file");
+        (*snapshot)["selected"] = box->GetId();
+
+        // What play mode does to the scene before Stop restores it
+        box->GetTransform().SetLocalPosition({9.f, 9.f, 9.f});
+        scene.CreateGameObject("spawned during play");
+        scene.CommitPendingAdditions();
+
+        check(SceneSerializer::LoadFromJson(scene, *snapshot), "restoring a snapshot must succeed");
+        scene.CommitPendingAdditions();
+        check(scene.GetObjects().size() == 2 && findByName(scene, "spawned during play") == nullptr,
+              "restoring must drop objects created after the snapshot");
+        const GameObject* restored = findByName(scene, "box");
+        check(restored != nullptr && close(restored->GetTransform().GetLocalPosition().x, 1.f),
+              "restoring must bring back the captured transforms");
+        check(scene.GetSelectedObject() == restored, "the selection must follow the restored object");
+
+        check(!SceneSerializer::LoadFromJson(scene, nlohmann::json{{"objects", 5}}),
+              "an invalid snapshot must be rejected");
+        check(scene.GetObjects().size() == 2, "a rejected snapshot must leave the scene alone");
+
+        SceneManager::GetInstance().Destroy();
+    }
 }
 
 void RunSerializationTests()
@@ -350,4 +384,5 @@ void RunSerializationTests()
     testSceneFileIdsAreLocal();
     testMaterialJsonRoundTrip();
     testSceneValidatesEmbeddedMaterials();
+    testPlayModeSnapshotRestore();
 }