Getting a ray from the mouse and camera

SDKTrays (OGRE default GUI)

1. Override createFrameListener to show the cursor.

   void MarbleGame::createFrameListener(void) {
   	BaseApplication::createFrameListener();
   	mTrayMgr->showCursor();
   }
   

2. When you need the ray from the camera through the cursor call:

   Ogre::Ray ray = mTrayMgr->getCursorRay(mCamera);
   

CEGUI

1. Look at the code in the mouseMoved method in OGRE's Intermediate Tutorial 3
2. You will call getCameraToViewportRay with the scene coordinates of the mouse (numbers between (0, 0) for the top left to (1, 1) for the bottom right.