A common mistake is to zero out `MinDepth` and `MaxDepth` of the `D3D11_VIEWPORT`, effectively clamping all depth to the near plane.

The default depth states are test enabled, write enabled, compare less.
See the [list at MSDN][1].


  [1]: https://msdn.microsoft.com/en-us/library/windows/desktop/ff476110%28v=vs.85%29.aspx