additions

public/materialsystem/igamewindow.h

@@ -3,7 +3,7 @@
 
 #include "tier0/platform.h"
 #include "tier2/iappsystem.h"
-#include "materialsystem/humandevice_enums.h"
+#include "humandevice_enums.h"
 
 typedef void ( *KeyCallbackFn )( EInputDeviceType eDevice, EInputButton eButton, bool bIsPressed );
 typedef void ( *AxisCallbackFn )( EInputDeviceType eDevice, EInputAxis eAxis, float fd );
@@ -26,6 +26,8 @@ public:
 
 	virtual void *CreateVulkanSurface( void *pInstance ) = 0;
 	virtual void DestroyVulkanSurface( void *pInstance ) = 0;
+
+	virtual bool IsValid() = 0;
 };
 
 abstract_class IGameWindowManager: public IAppSystem