1 files changed, 57 insertions, 0 deletions
diff --git a/src/ui/View.h b/src/ui/View.h
new file mode 100644
index 0000000..4ca512a
--- /dev/null
+++ b/src/ui/View.h
@@ -0,0 +1,57 @@
+#pragma once
+
+#include <memory>
+
+#define IMGUI_DEFINE_MATH_OPERATORS
+#include "imgui.h"
+
+class ViewManager;
+
+// A single screen of the UI, swapped in through the ViewManager.
+class View {
+public:
+    virtual ~View() = default;
+
+    virtual void Init() {}
+    virtual void Update() {}
+    virtual void Render() = 0;
+
+    void InternalInit(const std::shared_ptr<ViewManager>& manager) {
+        // Weak to avoid a cycle: the ViewManager owns the View.
+        this->mManager = manager;
+        this->Init();
+    }
+
+protected:
+    std::shared_ptr<ViewManager> Manager() const {
+        return mManager.lock();
+    }
+
+private:
+    std::weak_ptr<ViewManager> mManager;
+};
+
+// Owns the active View and drives its per-frame Update/Render.
+class ViewManager : public std::enable_shared_from_this<ViewManager> {
+public:
+    void SetView(const std::shared_ptr<View>& view) {
+        mCurrent = view;
+        if (mCurrent != nullptr) {
+            mCurrent->InternalInit(shared_from_this());
+        }
+    }
+
+    const std::shared_ptr<View>& Current() const {
+        return mCurrent;
+    }
+
+    void Render() {
+        if (mCurrent != nullptr) {
+            mCurrent->Update();
+            mCurrent->Render();
+        }
+    }
+
+private:
+    std::shared_ptr<View> mCurrent = nullptr;
+};