This time, we are going to take a look at a special class of texture, the cube map, and a
  couple of the common applications for cube maps, skyboxes and environment-mapped
  reflections.  Skyboxes allow us to model far away details, like the sky or distant scenery,
  to create a sense that the world is more expansive than just our scene geometry, in an
  inexpensive way.  Environment-mapped reflections allow us to model reflections on surfaces
  that are irregular or curved, rather than on flat, planar surfaces as in our Mirror Demo.
  The code for this example is adapted from the first part of Chapter 17 of 
    Frank Luna’s Introduction to 3D Game
    Programming with Direct3D 11.0.
  You can download the full source for this example from
  my GitHub repository, https://github.com/ericrrichards/dx11.git, under
  the CubeMap project.
  
    
      
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        | Our skull & columns scene, with a skybox and
        environment-mapped reflections on the column tops |