citerefentry"><span class="refentrytitle">EmitVertex</span></span></a>
            (or hasn't written it at all).
        </p>
        <p>
            In the tessellation control, tessellation evaluation and geometry languages,
            the <code class="varname">gl_PerVertex</code> named block is used to construct an array, <code class="varname">gl_in[]</code>
            of per-vertex or per-control point inputs whose content represents the corresponding
            outputs written by the previous stage