title: Android Sceneform Plane Detection and their angles
body: <p>I am trying to develop an Android app which is trying to draw a perfect line directly in front of me. My reference point is my phone, which means that the line has to parallel to my phone's left side.</p>
  
  <p>I have following issues:</p>
  
  <ul>
  <li>I am using Sceneform, so there is no "onSurfaceCreated" callback.(?)</li>
  <li>I assume that the white-dots shows the surface. But, then I think if there is a detected surface then I can place a Shape on it. But is can not happen sometimes. And sometimes, I can place a Shape even if there are no visible white-dots.</li>
  <li>When I try to draw a line between the points (0,0,0) to (1,0,0), it is not always parallel to the left side of my phone. I assume that the reason of this is related with the following fact : 
  
  <ul>
  <li>angle between the left-bottom corner of the detected surface and the left-top corner is not zero. (If we consider the coordinate system as follows : phone's left side is y-axis, bottom is the x-axis.)And this angle changes each time I reopen the app.</li>
  </ul></li>
  </ul>
  
  <p>These are more <strong>theory</strong> questions than the implementation. So, I need someone to prove or disprove, or give me guideline.</p>