c constants:
                    <code class="constant">GL_ALPHA</code>,
                    <code class="constant">GL_LUMINANCE</code>,
                    <code class="constant">GL_LUMINANCE_ALPHA</code>,
                    <code class="constant">GL_RGB</code>, or
                    <code class="constant">GL_RGBA</code>.</p></dd><dt><span class="term">
                <em class="parameter"><code>x</code></em>, <em class="parameter"><code>y</code></em>
                </span></dt><dd><p>Specify the windo