I was making a program that uses MDI (multiple document interface),
and each of the child windows in the main one have to be able to
display Direct3D graphics in them. How would you do this? I was
thinking of trying to create a new Direct3D device for each window but
then I heard this was bad (devices being "not so lightweight you can
create gobs and gobs of them" or something). If that's so, then what
is the "proper" way to do this, and how exactly do you do it, anyway?