Draw "OSM" as a view. ES 3.0: Tell tilers to discard depth/stencil of the backbuffer.

Also, don't even bind the UI texture unless there's UI to draw (probably negligible optimization).

UI/OnScreenDisplay.h

@@ -7,16 +7,25 @@
 #include "math/geom2d.h"
 #include "Common/StdMutex.h"
 
+#include "ui/view.h"
+
 class DrawBuffer;
 
 class OnScreenMessages {
 public:
 	void Show(const std::string &message, float duration_s = 1.0f, uint32_t color = 0xFFFFFF, int icon = -1, bool checkUnique = true);
 	void ShowOnOff(const std::string &message, bool b, float duration_s = 1.0f, uint32_t color = 0xFFFFFF, int icon = -1);
-	void Draw(DrawBuffer &draw, const Bounds &bounds);
 	bool IsEmpty() const { return messages_.empty(); }
 
-private:
+	void Lock() {
+		mutex_.lock();
+	}
+	void Unlock() {
+		mutex_.unlock();
+	}
+
+	void Clean();
+
 	struct Message {
 		int icon;
 		uint32_t color;
@@ -24,9 +33,18 @@ private:
 		double endTime;
 		double duration;
 	};
+	const std::list<Message> &Messages() { return messages_; }
+
+private:
 
 	std::list<Message> messages_;
 	std::recursive_mutex mutex_;
 };
 
+class OnScreenMessagesView : public UI::InertView {
+public:
+	OnScreenMessagesView(UI::LayoutParams *layoutParams = nullptr) : UI::InertView(layoutParams) {}
+	void Draw(UIContext &dc);
+};
+
 extern OnScreenMessages osm;