moure source/scenes a source/game/scenes

source/game/scenes/scene_registry.cpp

@@ -0,0 +1,20 @@
+#include "game/scenes/scene_registry.hpp"
+
+namespace scenes {
+
+    SceneRegistry& SceneRegistry::instance() {
+        static SceneRegistry inst;
+        return inst;
+    }
+
+    void SceneRegistry::registerScene(int state_key, Factory factory) {
+        factories_[state_key] = std::move(factory);
+    }
+
+    std::unique_ptr<Scene> SceneRegistry::tryCreate(int state_key) const {
+        const auto it = factories_.find(state_key);
+        if (it == factories_.end()) return nullptr;
+        return it->second();
+    }
+
+}  // namespace scenes