title: How Camera works in Libgdx and together with Viewport
body: <p>If you work with LibGdx it goes not long until you come to Camera and viewport. If you work the first time with camera and Viewport you get some questions about how it works and how to use it. So:</p>
  
  <ul>
  <li>How can I use a Camera in LibGdx? What's viewport width and height?</li>
  <li>What is a Viewport, how can I use it and how it works together with the Camera?</li>
  </ul>