title: Unity Textures don't show after coming back from another activity
body: <p>I have made a Android plugin for Unity that allows my app to open up different Android activities depending on the button that gets pressed (Unity buttons). The problem is that when you are in one of those activities and you press the back button to get to the Unity activity, the screen appears completely black, as if the textures were not loaded. This also happens when you press the home button and then get back to the app. However, the touch events on those buttons get triggered, when you pressed where they are supposed to be.</p>
  
  <p>Apparently, what is happening is that the <code>EGLContext</code> is getting lost. This is the log that shows it:</p>
  
  <pre><code>03-15 15:10:00.340: W/GLThread(16135): [egl.swap] mRequestPaused = true ,surface.valid = true
  03-15 15:10:00.340: I/GLThread(16135): mPaused is now true tid=12
  03-15 15:10:00.340: I/GLThread(16135): releasing EGL surface because paused tid=12
  03-15 15:10:00.340: W/EglHelper(16135): destroySurface()  tid=12
  03-15 15:10:00.340: W/EglHelper(16135): finish() tid=12
  03-15 15:10:00.350: I/GLThread(16135): releasing EGL context because paused tid=12
  03-15 15:10:00.350: I/GLThread(16135): waiting tid=12 mHaveEglContext: false mHaveEglSurface: false mPaused: true mHasSurface: true mWaitingForSurface: false mWidth: 1280 mHeight: 752 mRequestRender: false mRenderMode: 1
  </code></pre>
  
  <p>The <code>GLSurfaceView</code> reference says:</p>
  
  <blockquote>
    <p>EGL Context Lost</p>
    
    <p>There are situations where the EGL rendering context will be lost. This typically happens when device wakes up after going to sleep. When the EGL context is lost, all OpenGL resources (such as textures) that are associated with that context will be automatically deleted. In order to keep rendering correctly, a renderer must recreate any lost resources that it still needs. The onSurfaceCreated(GL10, EGLConfig) method is a convenient place to do this.</p>
  </blockquote>
  
  <p>The thing is that I don't really know how to get the context back, since it is all done by Unity.</p>
  
  <p>Any clues?</p>
  
  <p>Thanks!</p>