   Some questions on cube maps?
  So I'm trying to change my skybox to use a cubemap instead of 6 textures (easier to render in an effect file).  I've never really dealt with cube maps before and am having a little bit of trouble wrapping my head around them.So...1) I'm just trying to render this texture onto a normal cube.  Do I need to add a w texture coordinate to use cube maps?  So... I'd have 3 then: u,v,w2) What am I using to index into my cube map (with texCUBE).  Is it my view vector to the vertex in question, or my interpolated 3D texture coordinates?3) If I do need 3D texture coordinates... Are they straightforward to set by hand (for a cube) like the 2D texture coordinates were? I can find information on the concept of cube maps all over the web, but I'm just having a hard time visualizing them.Any help would be greatly appreciated :)   