IT set in <em class="parameter"><code>barriers</code></em> between passes is
                necessary.</p>
            </li>
            <li class="listitem">
              <p>Data written by the shader in one rendering pass and read by another
                mechanism (e.g., vertex or index buffer pulling) in a later pass need
                not use coherent variables or memoryBarrier().  Calling
                <code class="function">glMemoryBarrier</code> with the appropriate bits set in <em class="pa