   Turn Towards Mouse
  I wanted to make it so that it told me where the mouse was on the screen and then translate that to world coordinates then telling me towards what direction and how far from an object it was, the camera/screen is locked on this object and this object is able to move around freely. Hope the explanation wasn't too confusing. What I want to do with this is have a ship at the center of the screen that moves about in space. Depending on where your cursor is on the screen that's where the ship will turn.I use direct3d and c++. I've applied some scaling and projection matrices to the world view in case it's relevant.Thanks.   
  I would take the mouse cursor coordinates, re-center them so that (0,0) is the middle of your window, and then use the atan2 function to get a rotation angle. Then the ship object can be rotated around the vertical axis by the given angle, and voila [smile]   