no engine anymore

public/iappsystem.h

@@ -0,0 +1,17 @@
+#ifndef APP_SYSTEM_H
+#define APP_SYSTEM_H
+
+#include "tier1/interface.h"
+
+//----------------------------------------------------------------------------
+// App system is a module which has different applications based on the user's system.
+// For example rendering could use either Vulkan or Metal based on the system.
+//----------------------------------------------------------------------------
+abstract_class IAppSystem
+{
+public:
+	virtual void Init() = 0;
+	virtual void Shutdown() = 0;
+};
+
+#endif