title: OpenCV for Android: how to copy a Mat object (image) to another Mat?
body: <p>Both Mat objects contain (different) images. I want to copy <code>mSnapshot</code> over <code>mRgba</code>.
  I tried these (separately), but none of them seem to change <code>mRgba</code>:</p>
  
  <pre><code>mSnapshot.assignTo(mRgba);
  mSnapshot.copyTo(mRgba);
  mRgba = mSnapshot;
  </code></pre>
  
  <p>This throws an exception:</p>
  
  <pre><code>mRgba.setTo(mSnapshot);
  </code></pre>
  
  <p>And this does work, and sets <code>mRgba</code> to be a completely black image:</p>
  
  <pre><code>mRgba.setTo(new Scalar(0,0,0,255));
  </code></pre>
  
  <p>What am I missing?</p>
  
  <p>[Edit]
  The source files and exception can be found <a href="https://docs.google.com/open?id=0B-0tS2dxEWQ-OGI3NWFkOGYtYTczMS00YWIyLThlNjgtM2RkMDI4NzFkNDQ2" rel="nofollow">here</a>.</p>