feat(perfoverlay): add frame time and a/b testing stats

features/Performance Overlay/Shaders/Features/PerformanceOverlay.ini

@@ -0,0 +1,2 @@
+[Info]
+Version = 1-0-0

src/Feature.cpp

@@ -14,6 +14,7 @@
 #include "Features/InverseSquareLighting.h"
 #include "Features/LODBlending.h"
 #include "Features/LightLimitFix.h"
+#include "Features/PerformanceOverlay.h"
 #include "Features/ScreenSpaceGI.h"
 #include "Features/ScreenSpaceShadows.h"
 #include "Features/SkySync.h"
@@ -206,6 +207,7 @@ const std::vector<Feature*>& Feature::GetFeatureList()
 		globals::features::cloudShadows,
 		globals::features::waterEffects,
 		globals::features::weatherPicker,
+		globals::features::performanceOverlay,
 		globals::features::subsurfaceScattering,
 		globals::features::terrainShadows,
 		globals::features::screenSpaceGI,

src/Features/OverlayFeature.h

@@ -0,0 +1,36 @@
+#pragma once
+
+#include "Feature.h"
+
+/**
+ * @brief Abstract base class for all features that provide an in-game overlay.
+ *
+ * Inherit from OverlayFeature if your feature draws an ImGui overlay that can be toggled
+ * globally and/or individually. This interface allows the menu system to manage overlays
+ * in a generic way.
+ */
+struct OverlayFeature : Feature
+{
+	/**
+     * @brief Draw the overlay for this feature.
+     *
+     * This method should render the overlay UI using ImGui. It will only be called if
+     * IsOverlayVisible() returns true and the global overlay toggle is enabled.
+     */
+	virtual void DrawOverlay() = 0;
+
+	/**
+     * @brief Whether this overlay should be visible when the global overlay is enabled.
+     *
+     * Typically, this should return the value of a per-feature setting (e.g., ShowInOverlay).
+     * If false, the overlay will not be drawn even if the global overlay is enabled.
+     */
+	virtual bool IsOverlayVisible() const = 0;
+
+	/**
+     * @brief Get the category for UI grouping. Overlays default to "Debug".
+     *
+     * Subclasses may override this to provide a different category.
+     */
+	virtual std::string_view GetCategory() const override { return "Debug"; }
+};