title: Why transform normals with the transpose of the inverse of the modelview matrix?
body: <p>I am working on some shaders, and I need to transform normals. </p>
  
  <p>I read in few tutorials the way you transform normals is you <em>multiply them with the transpose of the inverse of the modelview matrix</em>. But I can't find explanation of why is that so, and what is the logic behind that?</p>