+ (let* ((getVideoDriver (get-irrlicht-proc "getVideoDriver" device))
+ (driver (getVideoDriver device)))
+ (if (null-object? driver)
+ (error "In procedure get-video-driver: Driver unavailable")
+ driver)))
+
+(define-method (is-window-active? (device <irrlicht-device>))
+ (let ((isWindowActive (get-irrlicht-proc "isWindowActive" device)))
+ (isWindowActive device)))