title: OpenGL - Share existing textures with future contexts?
body: <p>I have an application where I draw frames to a texture using the FBO extensions.</p>
  
  <p>These frames are then be displayed to different windows that are opened <strong>while</strong> the application is running. This means that textures can be created and pooled before the OpenGL context for any new window is created and <code>wglShareLists</code> is called.</p>
  
  <p>Currently I have to do <code>glReadPixels</code>, <code>glMapBufferRange</code> and <code>glTexSubImage</code> to move the texture into the different window contexts, which is rather inefficient.</p>
  
  <p>Any ideas on how to improve on this? Should I create multiple (as much as the maximum number of windows at any time ~4) OpenGL contexts and hidden windows during program startup? What would be the overhead of that?</p>
  
  <p>Or even better, is there a way to make textures shared between existing and <strong>future</strong> OpenGL contexts?</p>