title: Capture visual output of a DirectX application - even in background?
body: <p>I need to capture the visual output (like a screenshot) of a DirectX window.
  Currently, I use <a href="http://spazzarama.com//2009/02/07/screencapture-with-direct3d/" rel="noreferrer">this approach</a>.<br>
  But, when the window is in background, it captures whatever is in front of it.</p>
  
  <p>I see that DirectX windows render even when minimized or in background, so this should be possible.<br>
  But, how? (It also needs to be fast, and it needs to work on Windows XP too, unfortunately...)</p>
  
  <p><strong>Edit</strong>: I am very busy these days... Don't worry, I'll put the bounty back if it expires.</p>