Use ogre rtt in cegui 0.8

Ogre rtt in cegui  0.8

It's easy to display ogre rtt in cegui, but something should be taking care of.

1. set up ogre texture

mpOgreTexture = &static_cast<CEGUI::OgreTexture&>(getOgreRenderer()->createTexture("OgreTexture"));

mpOgreTexture->setOgreTexture(ogreRtt);   

2. set up cegui image, don't forget the image area.

mpImage = static_cast<CEGUI::BasicImage*>(&CEGUI::ImageManager::getSingleton().create("BasicImage",imageName));

mpImage ->setTexture(mpOgreTexture);

CEGUI::Rectf imageArea(0.0f, 0.0f, yourRttWidth, yourRttHeight);

mpImage->setArea(imageArea);

mpImage->setAutoScaled(CEGUI::ASM_Disabled);

3. set image property of your cegui window at last.

mpimgTex->setProperty("Image", imageName);

Be careful

      If your cegui window resides in FrameWindow, you must turn AutoRenderingSurface to false, 
      otherwise cegui will use imagery cash to display rtt.
      If you change rtt to another one at realtime, you need to call,
            mpimgTex->invalidate();
      this tell cegui to change texture, otherwise it will sill use display previous rtt.