title: How to make an overlay
body: <p>I'm wondering how I can create an overlay with Direct3D11 (C++).
  (Like the xfire game chat that renders content over another program in fullscreen)</p>
  
  <p>I know the basics of Direct3D11, but I have no idea how to make programs communicate with each other.
  Or is that not necessary?</p>
  
  <p>Could anyone help me?</p>
  
  <p>Thanks.</p>