OgreSystemInit

From CEGUIWiki

To start with you need to have an Ogre render window pointer in the mWindow variable. This is usually set earlier during Ogre initialisation as follows :

mWindow = mRoot->initialise(true);

Gui Initialisation (TaharezLook)

mGuiRenderer = new CEGUI::OgreCEGUIRenderer(mWindow, Ogre::RENDER_QUEUE_OVERLAY, 
         false, 3000,Ogre::ST_EXTERIOR_REAL_FAR);

mGuiSystem = new CEGUI::System(mGuiRenderer);
mWindowManager = &CEGUI::WindowManager::getSingleton();

CEGUI::Logger::getSingleton().setLoggingLevel(CEGUI::Informative);

CEGUI::SchemeManager::getSingleton().loadScheme("TaharezLook.scheme");

mGuiSystem->setDefaultMouseCursor("TaharezLook", "MouseArrow");

mGuiSystem->setDefaultFont("Tahoma-12");

mSheet = mWindowManager->createWindow("DefaultGUISheet", "root");

mGuiSystem->setGUISheet(mSheet);