title: What is interpolation in OpenGL?
body: <p>I have just started learning OpenGL ES 2.0, during the process I met some terms that do not make sense to me even if there are definitions. Like this one: <strong>Interpolation</strong></p>
  
  <p>From the book <em>OpenGL ES 2.0 Programming Guide</em>, I see this definition for <strong>interpolation</strong>:</p>
  
  <blockquote>
    <p>The mechanism used to generate a varying value for each fragment from the varying values assigned to each vertex of the primitive is called interpolation.</p>
  </blockquote>
  
  <p>Though I understand what <code>Linear Interpolation</code> is from <a href="https://stackoverflow.com/a/5249475/668963">this answer</a>, the definition above does not make sense to me.</p>
  
  <p>Would you put it another way and make an example to elaborate on what interpolation is?</p>