feat: add camera culling masks

tests/Components/test_game_object.cpp

@@ -4,6 +4,8 @@
 #include <XCEngine/Scene/Scene.h>
 #include <XCEngine/Core/Math/Vector3.h>
 
+#include <sstream>
+
 using namespace XCEngine::Components;
 using namespace XCEngine::Math;
 
@@ -64,6 +66,20 @@ TEST(GameObject_Test, NamedConstructor) {
     EXPECT_EQ(go.GetName(), "TestObject");
 }
 
+TEST(GameObject_Test, Layer_GetSetAndSerializeRoundTrip) {
+    GameObject source("LayeredObject");
+    source.SetLayer(7);
+
+    std::stringstream stream;
+    source.Serialize(stream);
+
+    GameObject target;
+    target.Deserialize(stream);
+
+    EXPECT_EQ(source.GetLayer(), 7u);
+    EXPECT_EQ(target.GetLayer(), 7u);
+}
+
 TEST(GameObject_Test, AddComponent_Single) {
     GameObject go;