title: OpenGL ES multi-texture alpha blending question
body: <p>This maybe a noob question, however, I haven't been able to find a suitable answers:</p>
  
  <p>I have an object in OpenGL ES (in fact, an UV mapped export from Blender) and I'd like to apply two textures to it. To be precise, I have a earth-like sphere and I would like to add two textures (a day-side and a night-side) to it.</p>
  
  <p>I had thought through alpha mapping, it should be possible to programmatically fade one texture and display the other during run-time so that my globe becomes a realistic simulation of the earth. I have the math behind it, i.e. creating the alpha-map for each face of the object is not the problem.  </p>
  
  <p>Any hints/pointers how this can be achieved?</p>
  
  <p>Thanks</p>