title: opengl overlay on camera view
body: <p>I still haven't found a proper way to show an opengl overlay oon top of camera preview,</p>
  
  <p>There's a hack, where you call</p>
  
  <pre><code>setContentView(GLSurfaceView)
  addContentView(MyCameraSurfaceView)
  </code></pre>
  
  <p>but it doesn't work properly - i.e. when you switch to anouther activity and go back, the opengl layer isnt displayed over camera preview.</p>
  
  <p>there are a lot of tutorials and samples which use the above method, but it simply doesn't work as expected</p>
  
  <p>does anyone know how they do it in layar</p>