title: Should glEnable(GL_TEXTURE_2D) be applied per texture unit
body: <p>In OpenGL I have always understood that <code>glEnable(GL_TEXTURE_1D)</code>, <code>glEnable(GL_TEXTURE_2D)</code> and/or <code>glEnable(GL_TEXTURE_3D)</code> (and corresponding <code>glDisable</code>) is a per texture unit parameter. </p>
  
  <p>Recently I tried to confirm this but have not found any clear documentation confirming either way regarding this question. </p>
  
  <p>Put simply and in code, should I be doing this </p>
  
  <pre><code>glActiveTexture(GL_TEXTURE0);
  glEnable(GL_TEXTURE_2D);
  ... bind etc ... 
  
  glActiveTexture(GL_TEXTURE1);
  glEnable(GL_TEXTURE_2D);
  ... bind etc ...
  </code></pre>
  
  <p>or this </p>
  
  <pre><code>glEnable(GL_TEXTURE_2D);
  
  glActiveTexture(GL_TEXTURE0);
  ... bind etc ...
  
  glActiveTexture(GL_TEXTURE1);
  .... bind etc ...
  </code></pre>
  
  <p>I was hoping to find some clarity. </p>