lass="citerefentry"><span class="refentrytitle">gl_FragCoord</span></span></a>)
            otherwise, the value written to <code class="varname">gl_FragDepth</code> is used.
            If a shader statically assigns to <code class="varname">gl_FragDepth</code>, then the value of the fragment's depth
            may be undefined for executions of the shader that take that path. That is, if the set of linked fragment
            shaders statically contain a write to <code class="varname">gl_FragDepth</code>